Decoding Cardiovascular Links to ICU Admission and Mortality in COVID-19

doi:10.21203/rs.3.rs-4980876/v1

Objective

In this study, we aimed to investigate cardiovascular complications in COVID-19 patients hospitalized at Shahid Faghihi Hospital and assess the correlation of these complications with the need for intensive care unit (ICU) admission and mortality.

Methods

A retrospective analysis was conducted on 216 COVID-19 patients admitted to Shahid Faghihi Hospital, randomly selected. Patient records were evaluated for laboratory findings, electrocardiography, echocardiography, and cardiovascular complications. The data were analyzed using SPSS software.

Results

Among the 216 patients studied, 89 (41.2%) were male, and 127 (58.8%) were female. The average age of the patients was 61.56 years. Patients requiring ICU admission had higher age, elevated lactate dehydrogenase (LDH), and higher D-dimer levels. Deceased patients also had higher LDH and D-dimer levels compared to recovered patients. Furthermore, deceased patients were more likely to have positive troponin and higher D-dimer levels. They exhibited more non-specific ST-T segment changes, Atrial fibrillation, right bundle branch block, rightward deviation of the heart's electrical axis, elevated ST segment, pericardial effusion, pleural effusion, and segmental pulmonary thromboembolism. Also, normal electrocardiography (ECG) had a protective effect on admission to the intensive care unit.

Conclusion

COVID-19 patients may experience not only respiratory syndromes but also cardiovascular complications, including myocarditis, stroke, and pulmonary thromboembolism, which can contribute to increased morbidity and mortality. Therefore, appropriate cardiovascular monitoring for COVID-19 patients is of paramount importance.ug.

COVID-19

cardiovascular system

mortality

stroke

pulmonary thromboembolism

The significance of cardiovascular complications and symptoms in COVID-19 patients cannot be overstated. However, before delving into the cardiac effects of this disease, it is worth noting that patients with pre-existing cardiovascular diseases, including coronary artery disease, heart failure, hypertension, and diabetes, had worse outcomes when afflicted with COVID-19 [1]. This was to the extent that the coexistence of two cardiac comorbidities was associated with a 2.59-fold increased risk of the need for intensive care unit (ICU) admission, mechanical ventilation, or mortality [2]. In terms of cardiovascular complications in COVID-19 patients, they suffered myocardial injury due to direct infection effects, hypoxemia, anemia, shock, decreased blood pressure, and acute kidney injury [3]. The crude prevalence of acute myocardial injury among hospitalized COVID-19 patients was approximately 20% [4]. The presence of acute myocardial injury was accompanied by a significantly increased risk of morbidity and mortality, and these patients also experienced more complications during hospitalization. For instance, they developed acute respiratory distress syndrome, malignant arrhythmias, acute coagulopathy, and acute kidney injury.

Patients also experienced acute coronary syndromes during hospitalization, likely due to increased activity of the coagulation and inflammatory systems, leading to the reduction of atherosclerotic plaque stability [5]. Regarding the bidirectional relationship between acute coronary syndrome and COVID-19, patients with acute myocardial infarction and ST-segment elevation who were also diagnosed with COVID-19 had a 1.21-fold higher likelihood of death compared to those without COVID-19 [6].

Thrombotic complications have also been observed to increase in COVID-19, attributed to the virus's interaction with platelets, microvascular injury, secretion of pro-inflammatory cytokines, and impaired endothelial function [7]. Among the thrombotic complications observed in COVID-19 patients, venous thromboembolism (VTE), including deep vein thrombosis (DVT), was more prevalent in hospitalized patients compared to non-hospitalized individuals, with an incidence of approximately 17.0% [8]. The prevalence of DVT was around 12.1%, and pulmonary thromboembolism (PTE) was approximately 7.1% in these patients [9]. Other thrombotic events observed in COVID-19 patients included catheter-related thrombosis, filter thrombosis in renal replacement therapy, and thrombosis of the portal and mesenteric veins [10].

In a study conducted by Kimal et al. in 2020 on 108 hospitalized COVID-19 patients, hypertension and diabetes were found to be the most common cardiovascular comorbidities, with prevalences of approximately 38% and 32.4%, respectively [11]. In the study by Pumtmann et al. conducted in 2020 on 100 recovered COVID-19 patients in Frankfurt, Germany, cardiac involvement was observed in 78 patients. Myocardial inflammation was confirmed based on endomyocardial biopsy findings and cardiac magnetic resonance imaging (CMR) in 60 individuals [12]. Another study by Neves et al. in 2022, involving 567 severe COVID-19 patients hospitalized in Brazil's intensive care units, found that myocardial injury, defined as an increase in troponin levels above 99 thermal units, was observed in 48.1% of the patients [13]. A study conducted by Villalba et al. in 2021 on 859 COVID-19 patients hospitalized in Spain revealed that the most predictive cardiovascular comorbidity for mortality in COVID-19 patients was diabetes [14]. In a study by Alshaikh et al. in Saudi Arabia in 2021, 206 hospitalized COVID-19 patients were examined. The authors found that the most common cardiovascular comorbidities in these patients were hypertension (48.1%), diabetes (45.1%), and ischemic heart disease (11.2%). Variables such as older age, male gender, hypertension, and diabetes were associated with a higher risk of cardiovascular events in Framingham scoring [15]. Furthermore, in a study conducted by Mazaherpour et al. in 2021 in Arak, Iran, involving 137 hospitalized COVID-19 patients, diabetes and hyperlipidemia were identified as independent predictors of cardiovascular events in these patients [16].

Having an accurate epidemiological view of various diseases, particularly during epidemics, can aid in resource allocation and planning. Additionally, having information on the complications of COVID-19 can assist in therapeutic and follow-up planning for patients. Given the absence of a proper understanding of the cardiac complications of COVID-19 in patients in Shiraz, we aimed to evaluate these complications in order to utilize the findings for future diagnostic and therapeutic planning.

This study is considered applied in terms of its objective and retrospective approach. The study population was selected from among COVID-19-diagnosed patients admitted to Faghihi Hospital. Based on a similar study by Suh et al. with an assumed type I error of 0.005 and a study power of 80% or considering the hospitalization of over 20,000 COVID-19 patients in the last two years, or considering a response distribution of approximately 50%, the minimum required sample size was determined to be 211 individuals. The inclusion criteria involved a positive PCR test for COVID-19, age between 18 and 75 years, and access to patient information and hospitalization records at Faghihi Hospital. The research protocol was developed using insights from previous studies, and a consensus among experts, including epidemiologists, cardiologists, infectious disease specialists, and statisticians, was reached regarding the critical indicators for extracting information from patient records.

Data obtained was entered into IBM SPSS version 26 for analysis. Qualitative variables were reported as counts and percentages, while quantitative variables were reported as means and standard deviations. Patients were categorized based on hospitalization in general wards or the ICU, the need for mechanical ventilation, and clinical outcomes (recovery or death). Qualitative variables in these groups were compared using the chi-square test. In contrast, standard quantitative variables were compared using the independent two-sample T-test, and non-standard quantitative variables were compared using the Mann-Whitney U test. Binary logistic regression was employed to predict each outcome based on cardiovascular events, and P-values less than 0.05 were considered statistically significant.

In this study, a total of 216 patients were investigated. Among the study participants, 89 (41.2%) were male, and 127 (58.8%) were female. Regarding the final hospitalization outcomes, 32 patients (14.8%) died, and 50 patients (23.1%) were admitted to the intensive care unit. A one-sample binomial test was employed to calculate these proportions' 95% confidence interval margins. The mean age of the patients in this study was 68.68 ± 61.56 years. The average pulmonary involvement of the patients in this study was 42.18 ± 18.524%.

Among the 166 patients hospitalized in regular wards, 66 were male, and 100 were female. Additionally, among the 50 patients requiring admission to the intensive care unit, 23 were male, and 27 were female. The chi-squared test was utilized to examine the relationship between gender and access to the intensive care unit, yielding a P-value of 0.432, indicating no significant difference in gender distribution between patients requiring admission to the intensive care unit and those hospitalized in regular wards. Furthermore, the average age of patients admitted to the intensive care unit was 64.43 ± 65.94, while patients in regular wards had an average age of 68.98 ± 60.25.Table 1 provides a summary of this analysis.

Table 1 : Comparison of the need for hospitalization in the intensive care unit according to demographic characteristics

Variable		Results		P-value
Variable		Regular Ward	ICU admission	P-value
Gender	Man	66 (39.8%)	23 (46.0%)	0.432
Gender	Woman	100 (60.2%)	27 (54.0%)	0.432
Age		60.25±13.985	65.94±12.643	0.011

In this study, among 184 recovered patients, 75 were male, and 109 were female. Additionally, among 32 deceased patients, 14 were male, and 18 were female. The chi-squared test was employed to examine the association between gender and mortality, yielding a P-value of 0.751. There was no significant difference in the gender distribution between deceased and recovered patients. Furthermore, the mean age of recovered patients was 13.817 + 60.08 years, while the mean age of deceased patients was 10.868 - 70.13 years. Due to the non-normal distribution of the age variable, the Mann-Whitney U test was used to compare this variable between the two groups. With a P-value less than 0.001, it was determined that patients who died had a higher age. Table 2 provides a summary of this analysis.

Table 2 : Comparison of the final outcomes according to demographic characteristics

Variable		Outcomes		P-value
		Recovery	Death
Gender	Man	75 (40.8%)	14 (43.8%)	0.751
	Woman	109 (59.2%)	18 (56.3%)
Age		60.08±13.817	70.13±10.868	0.001>

In this study, among 109 patients hospitalized in regular wards : 73 patients (61.3%) had negative troponin, 37 patients (31.1%) had borderline troponin, and nine patients (7.6%) had positive troponin. Also, among the 47 patients requiring hospitalization in intensive care units : six (12.8%) had negative troponin, while 26 patients (55.3%) had borderline troponin, and 15 patients (31.9%) had positive troponin. The chi-squared test was used to investigate the relationship between troponin and hospitalization in the intensive care unit, and according to the P-value less than 0.001, the group requiring hospitalization in the intensive care unit was more likely to have positive troponin. Also, the chi-squared test was used to investigate the relationship between troponin and the number of days hospitalization in hospital, and according to the P-value equal to 0.027, patients with positive troponin were hospitalized for a longer time. Also, the D-dimer of patients admitted to the intensive care unit was equal to 4119.32 ± 3512.632, and the average D-dimer of patients admitted to the regular wards was 1379.26 ± 1838.006. Considering that the distribution of D-dimer variable in Kolmogrov-Smirnov test was not normal, Mann-Whitney U test was used to compare this variable in two groups. According to P-value less than 0.001, it was found that patients who were hospitalized in intensive care units had higher D-dimer. Also, the chi-squared test was used to check the relationship between D-dimer and the duration of hospitalization. According to the P-value less than 0.001, it was found that patients with higher D-dimer levels were hospitalized for a longer time. Also, the average level of CRP was 72.94 in patients hospitalized in intensive care and 60.74 in patients hospitalized in regular wards. Although CRP values were higher in patients hospitalized in the intensive care unit, statistically significant relationship between CRP level and hospitalization in the regular ward or intensive care unit was not observed (P-value= 0.193). The average LDH level in patients hospitalized in the intensive care unit was 1062.75 and in patients hospitalized in the regular wards was 667.02, although there was a direct relationship between the LDH level and hospitalization in the intensive care unit, but this relationship was not statistically significant ( P-value=0.788 , r=0.265 ). The duration of hospitalization had a direct relationship with CRP and LDH ( r=0.151 and r=0.293 Respectively), but this relationship was statistically significant only between LDH and the number of days hospitalized ( P value= 0.193 and 0.014, respectively ). Table 3 and 4 provides a summary of this analysis.

Table 3 : Comparison of the need for hospitalization in the intensive care units according to laboratory characteristics

Variable		Results		P-value
Variable		Regular Ward	ICU admission	P-value
Troponin	Negative	73 (61.3%)	6 (12.8%)	0.001>
	Borderline	37 (31.1%)	26 (55.3%)
	Positive	9 (7.6%)	15 (31.9%)
D-dimer		1379.26±1838.006	4119.32±3512.632	0.001>
CRP		60.74	72.94	0.193
LDH		667.02	1062.75	0.788

Table 4 : Comparison of duration of hospitalization according to laboratory characteristics

Variable	P-value	Pearson Correlations(r)
Troponin	0.281	0.127
D-dimer	0.001>	0.415
CRP	0.193	0.151
LDH	0.014	0.293

In this study, the troponin levels of patients were recorded at three threshold levels: negative, borderline, and positive. Troponin levels were assessed in 166 patients, among whom 79 patients (47.5%) had negative troponin, 63 patients (38.0%) had borderline troponin, and 24 patients (14.5%) had positive troponin. A one-sample binomial test was used to calculate these findings' 95% confidence interval. Furthermore, D-dimer was evaluated in 209 patients, with a laboratory mean of 2580.431 ± 1995.44. LDH and CRP were checked in all patients. The duration of hospitalization varied from 2 to 12 days. Additionally, the D-dimer in recovered patients was in the range of 1559.85–1886.134, while in deceased patients, the mean D-dimer was 4171.806 ± 4404.84. Due to the non-normal distribution of the D-dimer variable, the Mann-Whitney U test was employed to compare the two groups, revealing a P-value less than 0.001, indicating that deceased patients had higher D-dimer levels. Moreover, the Mann-Whitney U test compared LDH and CRP between the recovery and dead groups. The results showed a P-value less than 0.001 for LDH and less than 0.035 for CRP, indicating that deceased patients had higher levels of LDH and CRP. Table 5 provides a summary of this analysis.

Table 5: Comparison of Final Outcomes Based on Laboratory Characteristics

Variable		Recovery	Death	P-value
Troponin	Negative	76 (56.7%)	3 (9.4%)	<0.001
	Borderline	46 (34.3%)	7 (53.1%)
	Positive	12 (9.0%)	12(37.5%)
D-dimer		1559.85±1886.134	4404.84±4171.806	<0.001
LDH				<0.001
CRP				0.035

This study compared ECG findings in patients admitted to regular wards and intensive care units. Among the 50 patients admitted to the intensive care unit, only 6.0% had a normal ECG. Still, among the 166 patients admitted to the regular wards, 54.8% had a normal ECG, which was statistically significant. (P-value < 0.001) The most common disorders in patients admitted to ICU were: Sinus tachycardia (P-value < 0.001), left bundle block ( P-value = 0.006 ), atrial fibrillation ( P-value = 0.001), The right bundle block ( P-value = 0.012 ) and the rightward deviation of the cardiac electrical axis ( P-value=0.012 ). Table 6 provides a summary of this analysis.

Table 6: Effect of ECG Type on ICU Admission

ECG findings		Regular Ward	ICU admission	P-value
Normal	No	75 (45.2%)	47 (94.0%)	<0.001
Normal	Yes	91 (54.8%)	3 (6.0%)	<0.001
Sinus tachycardia	No	143 (86.1%)	32 (64.0%)	<0.001
Sinus tachycardia	Yes	23 (13.9%)	18 (36.0%)	<0.001
Nonspecific ST-T changes	No	140 (84.3%)	38 (76.0%)	0.175
Nonspecific ST-T changes	Yes	26 (15.7%)	12 (24.0%)	0.175
Sinus bradycardia	No	154 (92.8%)	50 (100%)	0.073
Sinus bradycardia	Yes	12 (7.2%)	0 (0.0%)	0.073
Left bundle branch block	No	163 (98.2%)	44 (88.0%)	0.006
Left bundle branch block	Yes	3 (1.8%)	6 (12.0%)	0.006
Ischemic pattern	No	161 (97.0%)	47 (94.0%)	0.391
Ischemic pattern	Yes	5 (3.0%)	3 (6.0%)	0.391
Atrial fibrillation	No	166 (100%)	45 (90.0%)	0.001
Atrial fibrillation	Yes	0 (0.0%)	5 (10.0%)	0.001
Right bundle branch block	No	166 (100%)	47 (94.0%)	0.012
Right bundle branch block	Yes	0 (0.0%)	3 (6.0%)	0.012
Right axis deviation	No	166 (100%)	47 (94.0%)	0.012
Right axis deviation	Yes	0 (0.0%)	3 (6.0%)	0.012
Diffuse ST elevation	No	166 (100%)	48 (96.0%)	0.053
Diffuse ST elevation	Yes	0 (0.0%)	2 (4.0%)	0.053

This study compared the electrocardiographic findings of patients who either died or recovered. Among the 32 deceased patients, none had a normal electrocardiogram (ECG), whereas among the 184 recovered patients, 51.1% had a normal ECG. This difference was statistically significant ( P < 0.001). The observed disorders more frequently present in deceased patients included : non-specific ST-T changes ( P < 0.001 ), atrial fibrillation ( P < 0.001 ), right bundle branch block ( P = 0.003), rightward deviation of the cardiac electrical axis ( P = 0.003 ), and diffuse ST segment elevation (P = 0.001). Table 7 provides a summary of this electrocardiographic analysis.

Table 7: Comparison of Final Results Based on Electrocardiographic Features Found in the ECG

ECG Findings		Recovery	Death	P-value
Normal	No	90 (48.9%)	32 (100%)	0.001>
Normal	Yes	94 (51.1%)	0 (0.0%)	0.001>
Sinus tachycardia	No	149 (81.0%)	26 (81.3%)	0.971
Sinus tachycardia	Yes	35 (19.0%)	6 (18.8%)	0.971
Nonspecific ST-T changes	No	158 (85.9%)	20 (62.5%)	0.001
Nonspecific ST-T changes	Yes	26 (14.1%)	12 (37.5%)	0.001
Sinus bradycardia	No	172 (93.5%)	32 (100%)	0.221
Sinus bradycardia	Yes	12 (6.5%)	0 (0.0%)	0.221
Left bundle branch block	No	178 (96.7%)	29 (90.6%)	0.133
Left bundle branch block	Yes	6 (3.3%)	3 (9.4%)	0.133
Ischemic pattern	No	179 (97.3%)	29 (90.6%)	0.098
Ischemic pattern	Yes	5 (2.7%)	3 (9.4%)	0.098
Atrial fibrillation	No	184 (100%)	27 (84.4%)	0.001>
Atrial fibrillation	Yes	0 (0.0%)	5 (15.6%)	0.001>
Right bundle branch block	No	184 (100%)	29 (90.6%)	0.003
Right bundle branch block	Yes	0 (0.0%)	3 (9.4%)	0.003
Right axis deviation	No	184 (100%)	29 (90.6%)	0.003
Right axis deviation	Yes	0 (0.0%)	3 (9.4%)	0.003
Diffuse ST elevation	No	184 (100%)	30 (93.8%)	0.021
Diffuse ST elevation	Yes	0 (0.0%)	2 (6.3%)	0.021

This study evaluated the association between echocardiographic findings and final outcomes. Among the 34 recovered patients who underwent echocardiography, 17 individuals (50.0%) had a normal echocardiogram. Additionally, among the 12 deceased patients who underwent echocardiography, three individuals (25.0%) had a normal echocardiogram. Despite a higher prevalence of normal echocardiograms in recovered patients, this difference was not statistically significant, as indicated by a P-value of 0.183 in the chi-squared test. Furthermore, among the 34 recovered patients who underwent echocardiography, 14 individuals (41.2%) had a reduced left ventricular function. Among the 12 deceased patients who underwent echocardiography, nine individuals (75.0%) had a reduced left ventricular function. Although deceased patients showed a higher incidence of reduced left ventricular function, this difference did not reach statistical significance, with a P-value of 0.091 in the chi-squared test. Among the 34 recovered patients who underwent echocardiography, three individuals (8.8%) had a reduced right ventricular function. Among the 12 deceased patients who underwent echocardiography, six individuals (50.0%) had a reduced right ventricular function. The chi-squared test revealed a P-value of 0.005, indicating that deceased patients were more likely to have reduced right ventricular function. Table 8 provides a summary of this analysis.

Table 8: Comparison of Final Outcomes Based on Echocardiographic Characteristics

Echocardiographic Findings		Recovery	Death	P-value
Normal	No	17 (50.0%)	9 (75.0%)	0.183
Normal	Yes	17 (50.0%)	3 (25.0%)	0.183
Left ventricular dysfunction	No	20 (58.8%)	3 (25.0%)	0.091
Left ventricular dysfunction	Yes	14 (41.2%)	9 (75.0%)	0.091
Right ventricular dysfunction	No	31 (91.2%)	6 (50.0%)	0.005
Right ventricular dysfunction	Yes	3 (8.8%)	6 (50.0%)	0.005

This study evaluated the association between fluid accumulation in the third space and the need for hospitalization in the intensive care unit versus the regular ward. Among 166 patients hospitalized in the regular ward, five (3.0%) had pericardial effusion, while among 50 patients hospitalized in the ICU, nine (18.0%) had pericardial effusion. Patients were also examined for pleural effusion. Among 166 patients hospitalized in normal departments, 16 (9.6%) had pleural effusion, while among 50 patients hospitalized in ICU, 15 (30.0%) had pleural effusion. According to the P-value less than 0.001, patients hospitalized in the intensive care unit had more pleural effusion. Patients with plural effusion were further categorized into unilateral and bilateral effusions, and this relationship was investigated for each. Among 166 patients hospitalized in regular wards, eight (4.8%) had unilateral pleural effusion, while among 50 patients hospitalized in ICU, three (6.0%) had unilateral pleural effusion. According to the P-value equal to 0.719, there was no significant difference between the patients hospitalized in the special care units and those hospitalized in the regular wards regarding unilateral pleural effusion. Among 166 patients hospitalized in regular wards, eight people (4.8%) had bilateral pleural effusion, while among 50 patients hospitalized in ICU, 12 (24.0%) had bilateral pleural effusion. According to the P-value less than 0.001, the patients hospitalized in the intensive care unit were more likely to have bilateral pleural effusion. Table 9 provides a summary of this analysis.

Table 9: Comparison of the need for hospitalization in the intensive care unit according to the accumulation of fluid in the third space

Fluid accumulation		Regular Ward	ICU admission	P-value
Pericardial effusion	No	161 (97.0%)	41 (82.0%)	0.001
Pericardial effusion	Yes	5 (3.0%)	9 (18.0%)	0.001
Pleural effusion overall	No	150 (90.4%)	35 (70.0%)	0.001>
Pleural effusion overall	Yes	16 (9.6%)	15 (30.0%)	0.001>
Unilateral pleural effusion	No	158 (95.2%)	47 (94.0%)	0.719
Unilateral pleural effusion	Yes	8 (4.8%)	3 (6.0%)	0.719
Bilateral pleural effusion	No	158 (95.2%)	38 (76.0%)	0.001>
Bilateral pleural effusion	Yes	8 (4.8%)	12 (24.0%)	0.001>

The association between pericardial effusion and outcomes was evaluated. Among the 184 recovered patients, eight individuals (4.3%) had pericardial effusion, while among the 32 deceased patients, six individuals (18.8%) had pericardial effusion. The chi-squared test with a P-value of 0.008 indicated that deceased patients were more likely to have pericardial effusion. Additionally, plural effusion was examined in the patient population. Among the 184 recovered patients, 19 individuals (10.3%) had plural effusion, while among the 32 deceased patients, 12 individuals (37.5%) had plural effusion. The chi-squared test with a P-value less than 0.001 suggested that deceased patients were more likely to have plural effusion. Patients with plural effusion were further categorized into unilateral and bilateral effusions, and this relationship was analyzed. Among the recovered patients, 11 individuals (16.0%) had unilateral plural effusion, while none of the deceased patients had unilateral plural effusion. The chi-squared test with a P-value of 0.375 indicated no significant difference between dead and recovered patients regarding unilateral plural effusion. Moreover, eight individuals (4.3%) among the recovered patients had bilateral plural effusion, while 12 individuals (37.5%) among the deceased patients had bilateral plural effusion. The chi-squared test with a P-value less than 0.001 indicated that deceased patients were more likely to have bilateral plural effusion. Table 10 provides a summary of this analysis.

Table 10: Comparison of Final Results Based on Third Space Accumulation

Fluid accumulation		Recovery	Death	P-value
Pericardial effusion	No	176 (95.7%)	26 (81.3%)	0.002
Pericardial effusion	Yes	8 (4.3%)	6 (18.8%)	0.002
Pleural effusion overall	No	165 (89.7%)	20 (62.5%)	0.001>
Pleural effusion overall	Yes	19 (10.3%)	12 (37.5%)	0.001>
Unilateral pleural effusion	No	173 (94.0%)	32 (100%)	0.375
Unilateral pleural effusion	Yes	11 (6.0%)	0 (0.0%)	0.375
Bilateral pleural effusion	No	176 (95.7%)	20 (62.5%)	0.001>
Bilateral pleural effusion	Yes	8 (4.3%)	12 (37.5%)	0.001>

In this study, the association between the need for hospitalization in intensive care units and vascular complications of COVID-19, including stroke, deep vein thrombosis, and pulmonary thromboembolism, was investigated. Among the 166 patients hospitalized in regular wards, five patients (3.0%) suffered from stroke, and none of the 50 patients hospitalized in intensive care units suffered from this complication. According to the P-value equal to 0.592, there was no significant difference in stroke between these two groups. Among 166 patients hospitalized in regular wards, none had deep vein thrombosis, but among 50 patients hospitalized in intensive care units, three (6.0%) suffered from this complication. According to the P-value equal to 0.012, deep vein thrombosis was significantly higher in patients hospitalized in the intensive care unit. Among 166 patients hospitalized in regular wards, 17 patients (10.2%) suffered from pulmonary thromboembolism, and among 50 patients hospitalized in intensive care units, nine patients (18.0%) suffered from this complication. According to the P-value equal to 0.139, pulmonary thromboembolism was not significantly different between these two groups. Patients with pulmonary thromboembolism were then divided into different groups according to the clot size. There was no significant difference between patients requiring hospitalization in the intensive care unit and patients hospitalized in regular wards in terms of subsegmental and segmental pulmonary thromboembolism, but patients hospitalized in the intensive care units had significantly more massive pulmonary thromboembolism (6.0% vs. 0.0%) with P-value equal to 0.012. Table 11 provides a summary of this analysis.

Table 11: Comparison of Final Results Based on Vascular Complication

Vascular Complication		Regular Wards	ICU Admission	P-value
Stroke	No	161 (97.0%)	50 (100%)	0.592
Stroke	Yes	5 (3.0%)	0 (0.0%)	0.592
Deep vein thrombosis	No	166 (100%)	47 (94.0%)	0.012
Deep vein thrombosis	Yes	0 (0.0%)	3 (6.0%)	0.012
Pulmonary thromboembolism	No	149 (89.8%)	41 (82.0%)	0.139
Pulmonary thromboembolism	Yes	17 (10.2%)	9 (18.0%)	0.139
Pulmonary subsegmental thromboembolism	No	155 (93.4%)	44 (88.0%)	0.216
Pulmonary subsegmental thromboembolism	Yes	11 (6.6%)	6 (12.0%)	0.216
Pulmonary segmental thromboembolism	No	160 (96.4%)	50 (100%)	0.34
Pulmonary segmental thromboembolism	Yes	6 (3.6%)	0 (0.0%)	0.34
Massive pulmonary thromboembolism	No	166 (100%)	47 (94.0%)	0.012
Massive pulmonary thromboembolism	Yes	0 (0.0%)	3 (6.0%)	0.012

In this study, the association between outcomes and vascular complications of COVID-19, including stroke, deep vein thrombosis (DVT), and pulmonary thromboembolism (PTE), was investigated. Among the 184 recovered patients, five individuals (2.7%) experienced a stroke, while none of the 32 deceased patients had this complication. With a P-value greater than 0.99 in the chi-squared test, there was no significant difference in the occurrence of stroke between these two groups. Furthermore, among the 184 recovered patients, three individuals (1.8%) had deep vein thrombosis, while none of the 32 deceased patients experienced this complication. With a P-value greater than 0.99 in the chi-squared test, there was no significant difference in the occurrence of deep vein thrombosis between recovered and deceased patients. Among the 184 recovered patients, 20 individuals (10.9%) had pulmonary thromboembolism, while six individuals (18.8%) among the 32 deceased patients had this complication. The chi-squared test with a P-value of 0.206 indicated no significant difference in the occurrence of pulmonary thromboembolism between the two groups. Subsequently, patients with pulmonary thromboembolism were categorized into different groups based on clot size. Deceased and recovered patients did not significantly differ in terms of massive and segmental pulmonary thromboembolism. However, deceased patients were significantly more likely to have subsegmental pulmonary thromboembolism (18.8%) compared to recovered patients (60%) with a P-value of 0.013. Table 12 provides a summary of this analysis.

Table 12: Comparison of Final Results Based on Vascular Complications

Vascular Complication		Recovery	Death	P-value
Stroke	No	179 (97.3%)	32 (100%)	0.99<
Stroke	Yes	5 (2.7%)	0 (0.0%)	0.99<
Deep vein thrombosis	No	181 (98.4%)	32 (100%)	0.99<
Deep vein thrombosis	Yes	3 (1.6%)	0 (0.0%)	0.99<
Pulmonary thromboembolism	No	164 (89.1%)	26 (81.3%)	0.206
Pulmonary thromboembolism	Yes	20 (10.9%)	6 (18.8%)	0.206
Pulmonary subsegmental thromboembolism	No	173 (94.0%)	26 (81.3%)	0.013
Pulmonary subsegmental thromboembolism	Yes	11 (6.0%)	6 (18.8%)	0.013
Pulmonary segmental thromboembolism	No	178 (96.7%)	32 (100%)	0.595
Pulmonary segmental thromboembolism	Yes	6 (3.3%)	0 (0.0%)	0.595
Massive pulmonary thromboembolism	No	181 (98.4%)	32 (100%)	0.467
Massive pulmonary thromboembolism	Yes	3 (1.6%)	0 (0.0%)	0.467

In this study, all variables that had p-values less than 0.100 in the comparison between hospitalized patients in the ICU and regular wards entered a binary regression analysis. It was found that older age was associated with a higher likelihood of ICU admission, such that every 1-year increase in age made this chance 10.32 times higher. Also, positive troponin made the chance of ICU admission 4,655 times higher, and this ratio was 3.497, 7.409, 7.068, 2.435, and 6.337 for sinus tachycardia, left bundle branch block, pericardial effusion, overall pleural effusion, and bilateral pleural effusion, respectively. Table 13 summarizes this analysis.

Table 13: Examining the predictability of the need for ICU admission based on

Variable	Odds Ratio (OR)	P-value
Age	1.032	0.012
Troponin	4.655	0.001>
D-dimer	1.000	0.001>
Normal ECG	0.053	0.001>
Sinus tachycardia	3.497	0.001
Sinus Bradycardia	<0.001	0.99<
Left bundle branch block	7.409	0.006
Atrial fibrillation	N/A	0.99<
Right bundle branch block	N/A	0.99<
Right axis deviation	N/A	0.99<
Diffuse ST elevation	N/A	0.99<
Normal echocardiography	0.314	0.066
Right ventricular dysfunction	N/A	0.99<
Pericardial effusion	7.068	0.001
Overall pleural effusion	2.435	0.001>
Bilateral pleural effusion	6.237	0.001>
Deep vein thrombosis	N/A	0.99<
Massive pulmonary embolism	N/A	0.99<

In this study, 216 patients with COVID-19 were examined, and the cardiovascular complications of COVID-19 in these patients were investigated. Additionally, patients were compared based on the outcome and hospitalization in intensive care units regarding initial demographic characteristics, cardiovascular examinations, electrocardiography findings, echocardiography, and vascular complications. The findings of this study revealed that patients hospitalized in intensive care units and those who died had a higher age compared to patients hospitalized in regular wards and those who recovered. Furthermore, each year, an increase in age led to a 1.032-fold increase in the likelihood of hospitalization in intensive care units and a 1.062-fold increase in the likelihood of mortality. This study’s results align with other studies, such as the meta-analysis conducted by Bonanand et al., which also reported a higher mortality rate in COVID-19 patients in older age groups [17].

From a gender impact perspective on COVID-19 mortality, previous studies have shown that the mortality rate was higher in males compared to females. However, the difference between males and females was not statistically significant [18]. The current study’s mortality rate was 15.7% in males and 14.2% in females. In a study conducted by Cohen et al., the hospitalization rate in specialized care units for individuals aged 30-69 was higher than in other age groups, and the ICU admission rate for patients over 70 was lower than this traditional age group [19]. This difference in hospitalization rates may result from an age-based approach to admission to specialized care units, especially in situations where there are limitations in ICU beds, as was prevalent during the COVID-19 period in many regions [20].

In the study population, 14.5% of hospitalized COVID-19 patients tested positive for troponin. The positivity rate for troponin in patients hospitalized in intensive care units and deceased patients was significantly higher than in patients hospitalized in regular wards and those who recovered. In a study conducted by Abbasi et al. in Florida, USA, 27.6% of hospitalized patients had positive troponin, and these patients were more likely to experience mortality [21]. Similarly, in a de Guadiana-Rommualdo et al. study, more than 12% of patients had positive troponin [22]. Given the lower threshold for troponin in the current study, it could be due to the presence of a "borderline" troponin parameter in laboratory tests. Nevertheless, troponin positivity in COVID-19 patients is likely associated with myocardial injury, which could result from respiratory involvement and myocarditis-induced hypoxia [23].

In the studied population, normal ECG was observed in only 56.5% of patients, and the most common finding was sinus tachycardia, seen in 19% of patients. This increase in heart rate could result from physiological compensation against infection and fever reactions. In a study by Kaliyaperumal et al. involving over 300 COVID-19 patients in India, 2.9% of patients had rhythm disorders, including atrial fibrillation, and ST-segment abnormalities were observed in 16.9% of the patients. Cardiac rate disorders in that study were seen in 36.5% of patients, making it the most common electrocardiographic abnormality in that population [24]. The significant rhythm disorders found in the current study are broadly consistent with the Indian research. In the present study, sinus tachycardia, bundle branch blocks, right bundle branch block, atrial fibrillation, and right axis deviation were commonly observed during hospitalization in intensive care units.

In this study, patients were evaluated for the function of the left and right ventricles by echocardiography, conducted only in patients with clinical suspicion of heart failure. The prevalence of reduced left ventricular function in these patients was 50%, and the prevalence of reduced right ventricular function was 4.2%. Patients hospitalized in intensive care units and deceased patients had a higher prevalence of reduced right ventricular function. In a study by Bhatia et al. on 96 hospitalized COVID-19 patients, echocardiography was performed pointwise, indicating that subclinical reduction in left ventricular function was present in 90% of patients, demonstrating the profound effect of COVID-19 on the cardiac system [25].

Regarding fluid accumulation in the third space, pericardial effusion was observed in 6.5% of patients and pleural effusion in 14.4% of patients; both were associated with more hospitalizations in the intensive care unit and mortality. However, the impact of pleural effusion was only observed in cases of bilateral involvement, indicating more severe disease. In a study by Ghantous et al., all COVID-19 patients underwent echocardiography, and pericardial effusion was observed in 14% of patients, with some being asymptomatic [26]. The difference in the prevalence of pericardial effusion between the present study and Ghantous' study may be due to the fact that all patients in their research, including those without clinical suspicion, underwent echocardiography.

Furthermore, vascular complications of COVID-19 were investigated in the study population. Cerebral infarction was observed in 2.3% of patients, deep vein thrombosis in 1.4% of patients, and pulmonary thromboembolism in 14% of patients. Patients with subsegmental pulmonary thromboembolism experienced higher rates of mortality, which may be attributed to the critical complications that were not initially severe enough to be diagnosed. In a meta-analysis conducted by Namoni et al. in 2021, the prevalence of ischemic stroke was estimated to be approximately 1.22%, similar to the present study. In the same study, the authors found that more than 30% of COVID-19 patients with stroke died, which is significantly higher than the mortality rate solely attributed to COVID-19 [27]. However, in the present study, the rate of stroke in critically ill patients was not significantly higher; it was probably because some patients were in a bad condition that we could not transfer them to the CT scan department. Additionally, in a meta-analysis by Jig Ng in 2021, the occurrence of pulmonary thromboembolism among COVID-19 patients receiving prophylactic anticoagulation was calculated to be around 11.1% [28], which is roughly consistent with the 14% observed in the present study. In our study, all patients received prophylactic anticoagulation since admission.

This comprehensive study delves into the intricate landscape of cardiovascular complications associated with COVID-19, shedding light on critical aspects of morbidity and mortality in affected individuals. Analyzing a cohort of 216 patients, we discerned distinct patterns and correlations, thereby contributing pivotal insights to the scientific understanding of COVID-19's impact on the cardiovascular system.

Our findings corroborate existing literature, reaffirming the association between advanced age and adverse outcomes in COVID-19 patients. The study underscores the importance of age as a significant predictor of both intensive care unit (ICU) hospitalization and mortality, aligning with meta-analyses such as the impactful work by Bonanand et al.

Troponin positivity emerges as a noteworthy indicator of myocardial injury, revealing a potential link to respiratory involvement and myocarditis-induced hypoxia. Despite potential variations in troponin thresholds, our study consistently demonstrates a higher prevalence in ICU and deceased patients, suggesting its utility as a prognostic marker.

Electrocardiographic abnormalities, notably sinus tachycardia and rhythm disorders, were prevalent, accentuating the physiological compensatory mechanisms triggered by infection and fever. Echocardiographic assessments unveiled significant reductions in left and right ventricular functions, particularly pronounced in ICU and deceased patients, reinforcing the profound impact of COVID-19 on the cardiac system.

Fluid accumulation, manifesting as pericardial and pleural effusions, emerged as additional predictors of adverse outcomes. Bilateral pleural effusion, in particular, served as an indicator of disease severity.

Vascular complications, including cerebral infarction and pulmonary thromboembolism, added a crucial dimension to our understanding of COVID-19-related cardiovascular pathology. Mortality rates were notably higher in patients with subsegmental pulmonary thromboembolism, emphasizing the critical implications of such complications.

In conclusion, our study underscores the imperative for tailored cardiovascular monitoring in COVID-19 patients. The insights provided have implications for risk stratification, prognostication, and intervention strategies, necessitating a paradigm shift in the management of COVID-19 patients with cardiovascular involvement.

Suggestions for Future Research:

Exploration of Mechanisms: Further investigations into the underlying mechanisms of myocardial injury and troponin elevation in COVID-19 patients can enhance our understanding of the disease pathophysiology.
Longitudinal Studies: Longitudinal studies tracking the evolution of cardiovascular complications over time can offer insights into the dynamic nature of COVID-19-related cardiac manifestations.
Therapeutic Interventions: Research on targeted therapeutic interventions to mitigate cardiovascular complications is crucial, potentially influencing treatment strategies and improving patient outcomes.
Impact of Vaccination: As vaccination efforts progress, assessing the impact of vaccination on cardiovascular outcomes in COVID-19 patients is essential for informing public health strategies.
Diversity in Patient Populations: Including diverse patient populations in future studies can enhance the generalizability of findings and uncover potential disparities in cardiovascular manifestations.

By addressing these avenues, the scientific community can build on our findings, advancing knowledge and contributing to the refinement of clinical guidelines for managing COVID-19 patients with cardiovascular implications.

Ethical Approval

This research was conducted following the approval of the Research Ethics Committees of the School of Medicine at Shiraz University of Medical Sciences. The study was assigned the Approval ID IR.SUMS.MED.REC.1402.077 and received formal approval on May 6, 2023. The project, titled "Investigating Cardiovascular Complications Status of Patients Who Have Been Hospitalized Due to Previous COVID-19 Infection in Faghi Hospital, Shiraz, Iran 1399", was thoroughly reviewed and found to be in accordance with the ethical principles and the national norms and standards for conducting medical research in Iran. The committee's evaluation determined that the research adhered to ethical guidelines, including respect for patient confidentiality and the appropriate use of archived medical records.

Approval ID:	IR.SUMS.MED.REC.1402.077
Approval Date:	2023-05-06
Status:	Approved
Committee Evaluation:	The Biomedical Research Ethics Committee has confirmed that this project meets the necessary ethical requirements for research. However, it should be noted that the responsibility to meet all professional and legal requirements lies with the Principal Investigator (PI) and other collaborators involved in the project. Notice: The certificate issued by the committee is based on the documents submitted on May 6, 2023. Any modifications to the research proposal or documents must be reported to the committee promptly. This approval is specific to the research activities described in the original proposal and does not extend to any future changes without prior review by the committee.
Thesis Title	Investigating Cardiovascular Complications Status of Patients Who Have Been Hospitalized Due to Previous COVID-19 Infection in Faghi Hospital, Shiraz, Iran 1399
Committee Members:	Director: Dr. Ramin Shiraly Secretary: Dr. Laleh Dehghanpisheh

Consent to Participate

Given that this study involved the use of archived patient records without direct interaction with patients or the collection of new data, obtaining individual informed consent was not necessary. The data utilized was anonymized and handled with strict confidentiality in accordance with ethical standards and the guidelines provided by the Research Ethics Committee.

For any questions or additional information regarding ethical considerations, please contact the supervisor:

Supervisor:

Alireza Moaref, Email: [email protected]

Owrang Eilami, Email: [email protected]

Student:

Name: Sasan Hosseini Email: [email protected]

Consent to Publication

All authors involved in the preparation of this manuscript have read and approved the final version of the paper and have consented to its submission for publication. The authors confirm that the content is original, has not been published previously, and is not under consideration for publication elsewhere. By submitting this manuscript, the authors agree to transfer all publication rights to the journal, should the manuscript be accepted. The authors also agree to comply with the journal's policies regarding the submission and publication process.

Availability of Data and Materials

The datasets generated and/or analyzed during the current study are not publicly available due to privacy and confidentiality concerns related to the use of patient records. However, the data that support the findings of this study are available from the corresponding author upon reasonable request.

For access to the data, please contact:

Owrang Eilami (Corresponding Author)

Email: [email protected]

Seyed Sasan Hosseini (Other Corresponding Author)

Email: [email protected]

Requests for data will be evaluated based on the reason for use and in compliance with ethical guidelines and institutional policies. The data will be provided in a de-identified form to ensure patient confidentiality and adherence to data protection regulations.

Conflict of Interest Declaration

The authors of this paper declare that there are no conflicts of interest regarding the publication of this paper. The research was conducted independently and without any external influence that could affect the results or interpretation of the data. Specifically:

Financial Interests: The authors have no financial interests or relationships that could inappropriately influence or bias the content of this paper. No funding from pharmaceutical companies, medical device manufacturers, or any other commercial entities was received for this study.
Personal Relationships: The authors have no personal relationships with individuals or organizations that could be perceived as influencing the research outcomes.
Institutional Affiliations: The authors are affiliated with Shiraz University of Medical Sciences. The institution had no direct role in the design, data collection, analysis, or publication decisions of this research.
Intellectual Conflicts: There are no intellectual conflicts of interest among the authors. All research findings and interpretations presented in this paper are solely based on the data collected and the analysis conducted during the study.

The authors confirm that the manuscript has been read and approved by all of them, and that there are no other persons who satisfied the criteria for authorship but are not listed. Each author certifies that they have participated sufficiently in the work to take public responsibility for appropriate portions of the content.

Funding Information

This research was conducted as part of a student thesis at the School of Medicine, Shiraz University of Medical Sciences. The study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. All expenses related to the research, including data collection, analysis, and publication costs, were covered by the resources provided by the Shiraz University of Medical Sciences as part of the academic support for student research.

The authors declare that no external funding was obtained for this study. The research was carried out with institutional resources, and the authors had full independence in the design, execution, analysis, and interpretation of the research results.

Acknowledgments

The authors would like to thank the Shiraz University of Medical Sciences for providing access to the archived patient records and the necessary facilities to conduct this research. Additionally, we extend our gratitude to the staff at Faghi Hospital for their cooperation in providing the required data for this study.

Author Contributions

Sasan Hosseini: Conceptualized the research study, conducted the literature review, collected and organized the data from archived patient records, and drafted the manuscript. Sasan Hosseini was also responsible for coordinating the research activities and liaising with the research ethics committee for the necessary approvals.

Alireza Moaref: Supervised the overall research project, provided critical guidance in the study design, and contributed to the interpretation of the results. Alireza Moaref also reviewed and provided significant revisions to the manuscript.

Owrang Eilami: Co-supervised the research project, offered expert insights into cardiovascular complications, and assisted in shaping the research methodology. Owrang Eilami also contributed to the manuscript revisions and approved the final version for submission.

Mohsen Khabir: Performed the data analysis, including statistical analysis and interpretation of the data. Mohsen Khabir’s expertise was crucial in deriving meaningful conclusions from the data collected.

The first draft of the manuscript was written by Seyed Sasan Hosseini, and all authors commented on previous versions of the manuscript. All authors have read and approved the final version of the manuscript and agree to be accountable for all aspects of the work, ensuring the accuracy and integrity of the research.

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No competing interests reported.

Decoding Cardiovascular Links to ICU Admission and Mortality in COVID-19

Status:

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Abstract

Objective

Methods

Results

Conclusion

Introduction

Research Methodology

Findings

Discussion

Conclusion

Declarations

Ethical Approval

Consent to Participate

Consent to Publication

Availability of Data and Materials

Conflict of Interest Declaration

Funding Information

Acknowledgments

Author Contributions

References

Additional Declarations

Supplementary Files

Status:

Version 1