Demographic and clinical characteristics
A total of 3,025 patients were treated in the local STEMI network from March 2010 to September 2020. We excluded from the analyses 201 (6.7%) patients with non-STEMI and 114 (3.8%) transferred for p-PCI, therefore analyzing 2,710 consecutive STEMI patients treated according to pharmacoinvasive strategy (Figure 1). There was no significant difference between the analyzed and excluded groups in terms of in-hospital mortality (5.6% vs. 6.4% respectively, p=0.73).
Median age was 59 [51-66] years-old and 815 (30.1%) were women. Initial presentation was typical angina in 2506 (92.5%), anginal equivalent in 168 (6.2%) and cardiorespiratory arrest in 36 (1.3%) cases. Hypertension was present in 1,632 (60.2%), dyslipidemia in 1,335 (49.3%), diabetes mellitus in 837 (30.9%), previous myocardial infarction in 261 (9.6%) and chronic kidney failure in 183 (6.8%) (Table 1).
According to the Killip-Kimball classification, most patients had no signs of congestive heart failure prior fibrinolysis, with 2,539 (94.0%) patients in class I, 145 (5.4%) in class II or III and only 16 (0.6%) in class IV cardiogenic shock. Initial ECG exhibit anterior wall involvement in 1,268 (46.8%) and fibrinolytic therapy was performed with tenecteplase in 2629 (97.0%), alteplase in 57 (2.1%) and streptokinase in 23 (0.9%) patients.
Admission prognostic assessment revealed a mean TIMI score of 3.7 (± 2.3), GRACE score of 116.6 (± 38.4) and CRUSADE score of 26.9 (± 14.7), which predicted a 5.5% (± 2.9%) major bleeding risk.
Laboratory tests collected on admission to the tertiary center showed median values of troponin 3,900 [1,534 - 9,200] pg/mL, glucose 123 [103 - 164] mg/dL, total cholesterol 196 [166 - 228] mg/dL, HDL-cholesterol 40 [33 - 48] mg/dL, LDL-cholesterol 124 [100 - 152] mg/dL and triglycerides 131 [ 92 - 190] mg/dL.
Metrics of care
The time interval between symptom onset to the first-medical-contact was 120 [60 - 210] minutes and the door-to-needle time was 70 [43 - 115] minutes. Rescue-PCI was required in 929 (34.3%) patients, in whom the median fibrinolytic-catheterization time was 7.2 [4.9 - 11.8] hours compared to 15.7 [6.8 - 22.7] hours in those who had successful reperfusion criteria (Table 2).
Over the decade-registry, there was no significant change in the door-to-needle time when comparing the 42-month long tertiles, respectively 65 [42-100] min, 71 [45-110] min and 73 [45-120] min; p-value = 0,15. Time for rescue-PCI also showed no significant difference between tertiles, respectively 6.9 [4.6-11.2] hours, 7.1 [4.8-11.8] hours and 7.2 [4.9-12.0] hours; p-value = 0,28.
The infarct-related artery (IRA) was the left anterior descending in 1204 (44.4%) patients, right coronary in 1065 (39.3%), circumflex-marginal in 256 (9.5%), left main disease in 9 (0.3%) and could not be determined in 130 (4.8%). The remaining 46 (1.7%) patients did not undergo cardiac catheterization, either due to early death or to a contraindication to the procedure.
Coronary TIMI flow graded 3 through the IRA was observed in 1,614 (59.5%) patients in the initial angiography and in 2,106 (77.7%) at the end of the procedure, after PCI, if needed. Bare-metal stents were implanted in 1,843 (91.0%) patients and drug-eluting stents in 182 (9.0%).
Following fibrinolysis, 2025 (74.7%) patients were treated with percutaneous coronary intervention, 594 (21.9%) received optimal medical therapy without need for PCI and 91 (3.4%) underwent coronary artery bypass graft (CABG) surgery (Table 3).
Cardiovascular outcomes
All cause in-hospital mortality occurred in 151 (5.6%) patients, reinfarction in 47 (1.7%) and ischemic stroke in 33 (1.2%). Major bleeding occurred in 73 (2.7%) patients, including 19 (0.7%) cases of intracranial bleeding. Minor bleeding, mostly related to hematoma at the puncture site of cardiac catheterization, occurred in 97 (3.6%) patients.
The most frequent complication related to STEMI was acute heart failure, found in 1,162 (42.9%) patients. Cardiogenic shock occurred in 241 (8.9%) cases and isolated right ventricle heart failure in 124 (4.6%). Complex ventricular arrhythmias followed by sudden cardiac death, aborted or not, occurred in 228 (8.4%) cases, complete atrioventricular block in 139 (5.1%) and de novo atrial fibrillation in 94 (3.5%) (Table 4).
Patients admitted to the STEMI network could be considered at moderate baseline risk for major ischemic events during hospitalization according to prognostic scores of TIMI (3.7 ± 2.3) and GRACE (116.6 ± 38.4). C-statistic confirmed that both scores had high predictive values for in-hospital mortality, demonstrated by TIMI AUC-ROC of 0.80 (95% confidence interval 0,77 - 0.84 p-value < 0.01) and GRACE AUC-ROC of 0.86 (95% confidence interval 0.83 - 0.89 p-value < 0.01) (Figure 2).
The time elapsed until in-hospital mortality warns to the precocity of STEMI complications, as more than half of the deaths occurred in the first two days of hospitalization and 75% of them in the first five days (Figure 3).
Mechanical complications, diagnosed by echocardiography or necropsy, were identified in 13 cases (0.5%) of severe mitral regurgitation, 4 cases (0.14%) of ventricular septal defect and 2 cases (0.07%) of left ventricular free wall rupture. Necropsy was performed in only 14 cases of death.