In this retrospective study, we analyzed 63 patients with PA/IVS and CPS. All patients survived the intervention. Compared with CPS, the procedural time and anesthesia time of PA/IVS were significantly prolonged, as were the numbers of patients using PGE1 and vasoactive substances in the perioperative period, and postoperative MV time > 24 h was also significantly increased. During catheter intervention procedures, PA/IVS patients exhibit more unstable perioperative hemodynamics and SpO2. In addition, the incidence of cardiovascular adverse events during the perioperative period was higher in the PA/IVS group than in the CPS group.
Among the procedural risks of congenital cardiac catheterization, neonatal atretic valve perforation with or without valvuloplasty is at level 5, which is the most dangerous level [7]. In addition to the potential risks associated with the intervention itself, PA/IVS and CPS newborns are characterized by low age, low weight, cyanosis, pulmonary hypertension, and low cardiac output. which may increase their risks. For interventional treatment of PA/IVS and CPS neonates, the incidence of adverse events reported by different research centers ranges from 14–35% [2, 8, 9]. In the latest multicenter cohort from the United States, the incidence of adverse events was 25.7% for PA-IVS newborns who received catheter intervention during their first hospitalization. Coronary artery stenosis and low weight during the first intervention were important factors associated with adverse events [10]. In our PA/IVS cohort, the incidence of perioperative adverse events was 26.1%. Compared to PA/IVS newborns, the results of CPS PBPV were very good, with an overall success rate of 100% and an incidence of adverse events of only 2.5%, similar to the research results of Alakhfash et al. [5].
Newborns with PA/IVS and CPS depend on PDA to obtain sufficient PBF, requiring PGE1 to maintain PDA patency. Identifying RVDCC through TTE and CT before surgery is very important and affects the next treatment plan and surgical decision [11]. Patients with wider PDA and unrestricted atrial shunting can be placed in regular wards with continuous or discontinuous low-dose PGE1 treatment depending on the condition. However, regular wards must be able to perform echocardiography examinations and quickly transfer to the CICU in case of changes in condition. In addition, parents should be informed to pay attention to the occurrence of apnea events and other complications of PGE1. Newborns with hypoxia and unstable PDA blood flow should be closely monitored in the CICU to identify evolving physiological changes and monitor the dosage effect or side effects of PGE1. Neonates receiving PGE1 experience apnea events, which may require selective intubation and mechanical ventilation. If cyanosis is severe, it may be necessary to supplement low-concentration oxygen. Neonates with PA/IVS and CPS suffer from persistent worsening hypoxemia or acidosis without obvious pulmonary problems, which may indicate PDA closure and require emergency echocardiography. After confirming the patency of the PDA, sustained hypoperfusion or acidosis indicates a limited and insufficient atrial level shunt, which may require emergency intervention [12].
For patients with ductal-dependent PBF, hemodynamic management during anesthesia induction and maintenance should focus on maintaining appropriate pulmonary circulation and systemic circulation blood flow ratio, maintaining sufficient SVR to ensure adequate PBF. Anesthesia usually uses composite anesthesia induction and maintenance techniques, including opioid drugs, inhalation anesthetics, and muscle relaxants, as well as inhalation of low concentration oxygen. Usually, there is no need to use preanesthesia medication. Anesthesia induction can be achieved by inhalation or intravenous injection. Sevoflurane and propofol cause greater myocardial inhibition than fentanyl, etomidate, or ketamine, although all drugs can cause significant hypotension. When patients use nondepolarized muscle relaxants for intubation, the maintenance of anesthesia may be the combination of opioids and inhalation anesthesia [13]. In the absence of intravenous injection, sevoflurane inhalation induction without airway stimulation can be used. Immature myocardium is very sensitive to the inhibitory effect of volatile anesthetics, and sudden inhalation of high concentrations should be avoided. Cardiac catheterization usually causes minimal pain stimulation when placing vascular access sheaths. The infiltration of local anesthetics at the puncture site can be used to alleviate the pain caused by these interventions, but surgeons may not like it and may affect the pulsation of touching the puncture vessel [14]. The prepared liquid tube for liquid therapy should be carefully handled. The use of an infusion pump can accurately input the amount of liquid, and it is important to prevent hyperglycemia and hypoglycemia. When a neonate experienced tachycardia and hypotension, anesthesiologists should pay attention to whether it is caused by low blood volume. Because the operation time of CPS newborns is short, it is generally unnecessary to insert a urinary catheter. PA/IVS newborns should always rule out insufficient capacity, as intravascular volume consumption can increase cyanosis, but smaller urine volumes (0.5-2 mL/kg/h) may be difficult to measure. Therefore, diuretics are rarely used. According to the severity of cyanosis, a dose of 10–30 mL/kg should be used as the challenge dose [15]. Additionally, attention should be given to anticoagulation monitoring. Activated coagulation time (ACT) can be used to guide heparin targeting for > 200 s [16].
Due to the high position of the glottis in newborns, it may be difficult to intubate. If necessary, inhalation of sevoflurane can be attempted to check the exposure of the glottis before administering muscle relaxants. A stable venous pathway is necessary, usually with central venous catheterization. Ultrasound-guided arteriovenous puncture and catheterization can reduce puncture time and vascular damage. Invasive pressure measurement should be performed as much as possible. IBP can reflect early changes in PBF earlier than SpO2 [17]. Radial artery puncture should be carried out after anesthesia induction to reduce the discomfort of children and avoid ductal spasm. Generally, the left upper limb radial artery is selected to avoid the ipsilateral systemic pulmonary shunt side. The establishment of a central venous catheter is necessary for PA/IVS, as it can ensure a stable venous channel and the infusion of vasoactive drugs, including PGE1, norepinephrine, dobutamine, and fluid infusion. Of course, ultrasound guidance can be used to reduce the time and local trauma of arterial and central venous catheterization [18]. Ultrasound can improve the success rate of arterial puncture and catheterization, which is related to the ultrasound equipment and operating doctors in local hospitals. If radial artery cannulation is unsuccessful, IBP monitoring can be intermittently monitored by connecting the arterial pressure monitoring device after surgical femoral artery cannulation.
The infusion of PGE1 during the perioperative period should be based on the specific situation of the patient and the planned intervention plan. Connect the calculated dose of PGE1 to the venous pathway. For PA/IVS patients with finer PDA, continuous infusion is needed, while other patients are prepared for emergency use. In addition, when stent implantation is needed, the infusion of PGE1 needs to be suspended to obtain the best catheter contraction, reduce the occurrence of catheter stent-related complications, and may also help to minimize the problems related to pulmonary circulation excess [19]. The combination of norepinephrine and high-dose PGE1 can increase systemic afterload, reduce PVR, and improve lung perfusion. It should be considered that the use of catecholamines is accompanied by an increase in oxygen consumption (heart rate) and can offset the benefits of improved SpO2, even leading to metabolic acidosis [20].
The crisis events in hemodynamics mainly arise from the impact of the intervention procedure on PBF. Anesthesiologists should closely monitor changes in vital signs during the procedural process. This monitoring becomes even more crucial during the stage where the use of wires and catheters could reduce PBF. For patients with ductal-dependent PBF, risks and injury to the femoral artery could be significantly reduced if the procedure only requires access through the femoral vein and does not involve catheterization through the PDA. According to our observations, hemodynamic crisis events during the process of cardiac catheterization mainly concentrate on three stages: (I) In newborns, the space in the ventricle is small, and mechanical stimulation from guide wires or catheters during procedures can cause arrhythmia, leading to reduced cardiac output and decreased pulmonary blood flow. (II) When guide wires or catheters pass through the arterial duct and enter the main pulmonary artery, they can obstruct part of the PDA and even cause temporary spasms, resulting in decreased pulmonary blood flow. (III) When a balloon is used to dilate the pulmonary valve, the inflated balloon can obstruct the right ventricular outflow tract, particularly in CPS patients without PDA, leading to a significant reduction in PBF.
The general risks associated with neonatal cardiac catheterization include arrhythmia, difficulty in establishing vascular access, vascular injury, myocardial perforation, and bleeding. For patients who require ductal stenting support, complications also include stent thrombosis and displacement.
The most common cardiovascular adverse event during the perioperative period is transient arrhythmia, with an incidence rate of 10%-29.2%, mostly caused by the manipulation of guide wires or catheters [21, 22]. This may be due to the mechanical stimulation of cardiac nerves or direct irritation of the myocardium by the devices used during the procedure. In most cases, cardiac arrhythmias will spontaneously subside and do not require treatment. If arrhythmia has clinical significance, the first treatment to be used is to stop the catheter procedure. In cases where arrhythmia cannot be resolved through catheterization, treatment should be carried out according to neonatal arrhythmia guidelines, including medication, electrical cardioversion, and even cardiopulmonary resuscitation [23]. If not handled in a timely manner, arrhythmia may lead to cardiac arrest. In a study of 7289 procedures, the researchers found that there were 70 cases of cardiac arrest, of which 38 were caused by arrhythmia, indicating that arrhythmia should not be taken for granted [24]. In our case, transient arrhythmias were relatively common, with most cases recovering sinus rhythm by pausing surgical procedures, withdrawing the catheter, and only one case developing supraventricular tachycardia that required medication maintenance treatment.
Vascular-related injuries are also common, mostly involving the femoral artery. When establishing catheter access, the blood vessels of newborns are thinner. If the puncture and catheterization are not smooth, arterial vasospasm will occur. If the outer diameter of the indwelling arterial sheath is large and blood anticoagulation is insufficient, thrombosis may form, and even thrombotic occlusion may occur. In a study on PDA stent placement reported by Agha, femoral artery thrombosis occurred in 7 newborns (7.2%) [25]. A study by Tadphale et al. suggested that a diameter of less than 3 millimeters in the femoral artery and a ratio of sheath outer diameter to vascular lumen diameter greater than 50% are associated with an increased risk of experiencing palpable disappearance of femoral artery pulsation at the end of surgery [26]. Multiple studies have shown that low body weight, larger arterial sheath diameter, and longer surgical time are independent risk factors for femoral artery injury [27]. Alexander et al. indicated that the use of ultrasound guidance in pediatric cardiac catheterization can reduce the incidence of loss of arterial pulse (LOP) requiring treatment [28]. In summary, newborns with femoral artery catheterization may experience differences in pulse intensity between the lower limbs on both sides and even develop LOP. Before surgery, the diameter of the femoral artery should be measured using conventional ultrasound, and a smaller guiding sheath should be used to actively avoid entering the femoral artery when the FA diameter is less than 3 millimeters. When LOP is noted at the end of the surgery, ultrasound evaluation and Doppler pulse assessment of the dorsal foot artery should be performed, and anticoagulant therapy should be administered if necessary. In our study, neonatal vascular injury in CPS was relatively rare, as only 3 patients underwent femoral artery catheterization, with 2 patients experiencing differences in the pulsation of both femoral arteries. Confusingly, a CPS patient was found to have femoral vein occlusion and collateral formation during the second procedure. Most PA/IVS patients had differences in bilateral femoral artery pulsation, but no LOP occurred. One patient with PA/IVS developed a femoral arteriovenous fistula after surgery.
According to anatomical variations, newborns with PA/IVS who undergo PPVP have a relatively high risk of surgical complications, especially right ventricular or main pulmonary artery perforation. A multicenter study by the Congenital Catheterization Research Collaboration showed that the risk of cardiac perforation was 10.5%, with a higher risk of using radiofrequency catheterization compared to wire catheterization [9]. In a study by Lawley et al., out of 12 initial treatment cases of PA/IVS pulmonary valve perforation, 2 patients developed pericardial tamponade requiring emergency ECMO support due to pulmonary artery perforation [29]. A study on interventional cardiac catheterization of newborns: results from the Italian multicenter experience. In 1423 neonatal cardiac catheterization procedures, a total of 47 cases of pericardial effusion occurred, of which 12 cases required drainage tube placement [30]. A higher Catheterization RISk Score for Pediatrics (CRISP), lower age, and surgical category (PPVP) are independent predictors of cardiac perforation [31]. In this study, two patients had cardiac or main pulmonary artery perforation, one patient had mild pericardial effusion that was not treated, and another patient underwent open chest hybrid surgery.
Ductal stenting is highly correlated with severe adverse complications. Dutal spasm and dissections can occur in rare cases [32]. When using a guide wire to pass through PDA, extreme caution should be exercised. In the case of dutal spasm, the wire and catheter should be withdrawn, and PGE1 should be continuously infused. If not relieved, a stent or BT needs to be urgently inserted. In a few cases, stent migration or displacement may occur, and reducing the chance of this complication can be accomplished by fully constraining the DA by ceasing PGE1 administration [33]. In rare cases, it may be necessary to urgently remove the stent in the operating room and switch to a BT shunt. Ductal stenting can also artificially cause severe low diastolic blood pressure or compress the left main bronchus [34, 35]. In our case, one child experienced spasms and partial occlusion when the guide wire passed through the PDA, resulting in the urgent implantation of a ductal stent.
Although the risks in neonatal cardiac catheterization can be reduced, they cannot be avoided. Some researchers have reported improved surgical techniques or intervention tools, most of which use coronary guide wires, coronary artery balloons, and various types of catheters. In addition to intervention methods and techniques, future research should aim to develop and produce intervention tools suitable for newborns. Smaller catheters, lower contour balloons and stents, and creative vascular access techniques make percutaneous intervention possible for the smallest newborns [36]. For example, both current radiofrequency drilling and wire tip drilling pose a risk of myocardial perforation. Developing a device similar to the three-dimensional mapping for the treatment of arrhythmia [37] and applying it to the anchoring target of the central position of the pulmonary valve is also a research direction.
This study has several limitations. First, this study reviewed the immediate complications during the perioperative period. Due to follow-up issues, the long-term prognosis and complications were not statistically analyzed. Second, a multicenter, large-sample observational study is needed to further classify the surgery in detail, determine the risk factors for cardiovascular adverse events, and develop an individualized perioperative management plan. Finally, due to sample size limitations, it is difficult to include more factors for multivariate analysis.