Brief Report Myocardial Protection During Neonatal Cardiac by Madan Mohan Maddali, John Valliattu, Jutta Fahr, Taha al Delamie, and Sunny Zacharias Royal Hospital, Muscat, Oman

Summary Myocardial protection is of major concern in neonatal where coronary ostial transfer Downloaded from https://academic.oup.com/tropej/article/52/1/59/1643726 by guest on 01 October 2021 is required as part of the surgical procedure. Retrograde coronary sinus perfusion (RCSP) of cold cardioplegic solution was evaluated in infants undergoing arterial switch operations. Hemodynamic measurements and postoperative cardiac troponin I (cTnI) levels were estimated in addition to transthoracic to assess the extent of myocardial injury. The results were compared with a similar cohort of patients where ante grade selective coronary artery perfusion (ASCP) was used during coronary ostial transfer. Our experience suggests that RCSP is a useful option in this subset of patients.

Introduction coronary sinus perfusion (RCSP group) and the The present study was undertaken to assess the other eight consecutive neonates received cardiople- clinical viability of retrograde coronary sinus perfu- gia by antegrade selective coronary artery perfusion sion (RCSP) as a myocardial protection strategy in (ASCP group). Topical cooling was employed in neonatal cardiac surgery. both groups In the RCSP group, 10 ml/kg of retrograde was infused using a size 6 Foley’s Materials and Methods (Fig. 1), which was repeated every 20 min This report includes 16 newborns that had and was delivered at a pressure of less than d-transposition of the great vessels (DTGV) with 20 mmHg. In the ASCP group, the coronary ostia variable sizes of ventricular septal defect (VSD) as were cannulated directly and 10 ml/kg cardioplegia diagnosed by echocardiography. All neonates were was infused at a pressure of less than 25–30 mmHg deemed to be good candidates for surgery based every 20 min. on good left ventricular mass and left ventricular Thirty minutes after termination of CPB the end diastolic volumes. After an approval from the hemodynamic parameters were compared between Institutions’ Ethical Committee and informed con- the two groups. Cardiac troponin I (cTnI) levels were sent from the parents it was decided to proceed with measured regularly in both groups postoperatively. arterial switch procedures in all 16 neonates. The postoperative clinical course was evaluated All patients received narcotic-based general anaes- based on the dose of vasoactive drugs required, thesia with standard invasive and non-invasive hemodynamic indexes, incidence of , hemodynamic monitoring. The surgical team was transthoracic echocardiographic assessment, and the same for all the cases. duration of ventilatory support. After institution of (CPB) and application of aortic cross clamp (ACC), all neonates received 15 ml/kg of St. Thomas Results cardioplegia solution at a temperature of 6C, The demographic data, preoperative hemodynamic which was administered into the aortic root at a status, and laboratory investigations as well as pressure less than 40 mmHg. Cardioplegia delivery the CPB data were comparable in both groups pressure was always monitored (Gish Biomedical (Table 1). Inc., CA, CCS-500, USA). All neonates in the RCSP group were on dopa- For further myocardial protection, eight consecu- mine and nitroglycerine 30 min from termination tive neonates received cardioplegia by retrograde of CPB. These drugs were infused for the duration of artificial ventilation. In the ASCP group, all patients received dopamine 30 min post-CPB, which was con- Correspondence: Dr Madan Mohan Maddali, Royal tinued for the duration of artificial ventilation. The Hospital, P.B.No: 1331, P.C: 111, Seeb, Muscat, Sultanate ASCP group needed additional adrenaline infusion of Oman. E-mail [email protected]. for a mean duration of 7.5 1.8 days (Table 2).

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Hemodynamic indexes were similar with no detect- able ischemic changes in either group (Table 2). No arrhythmias were detected in the RCSP group postoperatively. In the ASCP group, two neonates needed AV sequential pacing for 24 h and two neonates exhibited self-sustaining supraventricular tachycardias. The duration of artificial ventilation was much shorter in the RCSP group than in the ASCP group ( p50.01); one neonate in the ASCP group required reintubation (Table 2). Both groups had elevated levels of cardiac troponin I (cTnI) which normalized after about a week in both groups. None of the Downloaded from https://academic.oup.com/tropej/article/52/1/59/1643726 by guest on 01 October 2021 patients needed peritoneal dialysis, and the renal and hepatic parameters were near normal in all cases. There was one case of delayed sternal closure in the ASCP group. Transthoracic echocardiography was performed on the second postoperative day, which revealed good biventricular contractility in all cases, with normal E to A ratios (RCSP group, 1.1 0.1; ASCP group, 1.1 0.2). All newborns survived the operative procedure and were well at the end Fig. 1. Schematic representation of the retrograde of 30 days. cardioplegia catheter insertion. Tricuspid valve leaflets include the anterior (A), posterior (P), Discussion and the septal (S) leaflets. The bundle of His (b) Myocardial protection is of prime importance in courses along a line from the coronary sinus (CS), neonates, where the surgical procedure requires to the anterospetal commissure. The atrioven- prolonged CPB times.1 Deep hypothermic circula- tricular node (AVN) lies between this area and tory arrest techniques, although an option, are the CS. The purse string was snugged around the associated with higher risks of neurological abnor- tip of the Foley’s catheter taking care to avoid malities.2 ASCP technique involves direct coronary the AVN. cannulation with the possibility of traumatic damage

Table 1 Demographic, preoperative and CPB data

RCSP (n ¼ 8) ASCP (n ¼ 8)

Age (days) 5.33 2 (range 3–7) 5.7 2.7 (range 3–9) Weight (kg) 3.6 0.4 3.8 0.5 Cardiological interventions: Atrial septostomy with prostaglandin infusion 3 neonates 3 neonates (0.05 mg/kg/min), preoperative ventilatory and inotropic support (dopamine 10 mg/kg/min each) Preoperative Lab. investigations: Hemoglobin 13.3 1.3 12.7 0.7 Platelets 377.6 207 352 153 Urea (normal 2.5–6.5 mmol/l) 3 1.9 2.8 0.2 Creatinine (normal 40–70 mmol/l) 65 46.8 71.5 33 ACC (min) 97.5 13 91 5.8a CPB time (min) 210 10.9 216.5 4a Lowest nasophrayngeal temperature reached (C) 24 20 while weaning from CPB None needed None needed Total cardioplegia (ml/kg) 56.5 19.8 51.2 2.5a Intraoperative urine output (ml) 56 2.9 60 4.4

All data are expressed as mean SD. ap ¼ NS [T-test (two-tailed)].

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Table 2 Postoperative events

Event RCSP (n ¼ 8) ASCP (n ¼ 8)

ECG ischemic changes Nil Nil No. of cases that needed pacing during post-CPB period 1 2 (Atrial pacing) (AV sequential pacing) Hemodynamic data:a Arterial systolic pressure (mmHg) 68 869 6 rate (beats/min) 149 13 150 14 Mean LAP (mmHg) 7 3.9 7.5 2.6 Mean CVP (mmHg) 8 28 1.9 Inotropes/vasodilators 30 min post-CPB (mg/kg/min) Dopamine: 7.5 2.9 Dopamine 7.5 2.8 Downloaded from https://academic.oup.com/tropej/article/52/1/59/1643726 by guest on 01 October 2021 Nitroglycerine: 0.5 0.2 Adrenaline: 0.09 0.03 Arrhythmias in the postoperative unit (no. of cases) 0 2- SVT Duration of ventilation (days) 4.8 1.7 13.5 1.7 ( p50.01)b Reintubation 0 1 Cardiac enzymes Cardiac troponin I (cTnI) 6 h post-ACC 39 0.3 40 0.2 12 h post-ACC 40 0.3 42 0.3 24 h post-ACC (420 ng/ml, significant) 45 0.8 46 0.2 Normalization (in days) 6.8 0.9 7.2 0.5 Renal parameters (2nd postop. day): Urea (4.2–7.2 mmol/l) 3.8 0.9 4.3 1 Creatinine (60–120 mmol/l) 55.25 18.3 80.5 45.9 Delayed sternal closure 0 1

All data are expressed as mean SD. LAP, left atrial pressure; CVP, central venous pressure. aHemodynamic stability as assessed 30 mins post cardiopulmonary bypass. bT-test (two-tailed). to the coronary ostia and postoperative coronary it is difficult to draw any definitive conclusions. occlusion.3,4 However the ASCP group demonstrated a trend Some experimental studies have shown that towards a need for additional inotropic support, RCSP might underperfuse the right ventricular free cardiac pacing, prolonged ventilatory support wall,5 which was not substantiated by most clinical resulting in prolonged ICU stay and incidence of studies.3 This discrepancy might be due to better arrhythmias. right ventricular protection due to the use of Our use of a Foley’s catheter for RCSP has to intraoperative topical hypothermia. be highlighted. The balloon of the Foley’s was not We encountered no problems related to either inflated in order to avoid occlusion of the right right or left ventricular preservation, as all our coronary . A 5 ‘O’ prolene purse string suture patients could achieve stable hemodynamics at a was applied around the mouth of the coronary low preload (low LAP and CVP). Yet, these indices sinus avoiding the AV node to prevent the spillage may lack sufficient sensitivity to establish mild of cardioplegia. Even cardioplegic distribution was ventricular damage. confirmed by efflux of the cardioplegia solution Good results have been reported when blood from both coronary ostia. cardioplegia6 or albumin-enriched asanguineous Our results suggest that RSCP is a safe myocardial cardioplegia solution was used for intermittent protection technique in neonates. RSCP avoids ostial RCSP.3 In spite of using plain asanguineous cardio- cannulation and the possibility of trauma, allows plegia, myocardial compliance seemed to have been uninterrupted surgical procedures and wash out of normal in our study, which was probably due to air/debris from the coronary arteries. Surgery could the low perfusion pressure at which the retrograde be performed at moderate hypothermia. A com- cardioplegia was delivered. Although the RCSP bination of antegrade aortic root cardioplegia technique is supposed to shorten ACC time3 we did infusion and RCSP might result in better myocardial not find any such difference between the two groups protection. (Table 1). According to this pilot study, RCSP using a simple We acknowledge that this is a non-randomized device appears to be an attractive alternative to study with a small patient population and hence ASCP in infants undergoing major cardiac surgery.

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References 4. DeLeon SY, Idriss FS, Ilbawi MN, Duffy CE, 1. Hartz RS, Deleon SY, Dorotan JG, Urbina EM. Benson DW Jr, Backer CL. Comparison of single Multidose cardioplegia in a complex arterial switch versus multidose blood cardioplegia in arterial procedure. Ann Thorac Surg 2002; 73: 280–82. switch procedures. Ann Thorac Surg 1988; 45: 548–53. 2. Bellinger DC, Jonas RA, Rappaport LA, et al. 5. Allen BS, Winkelmann JW, Hanafy H, et al. A comparison of the developmental and neurologic Retrograde cardioplegia does not perfuse the status at one year of children who underwent right . J Thorac Cardiovasc Surg 1995; 109: heart surgery using hypothermic circulatory arrest 1116–24. or low-flow cardiopulmonary bypass. N Engl J Med 6. Drinkwater DC Jr, Cushen CK, Laks H, 1995; 332: 549–55. Buckberg GD. The use of combined antegrade- 3. Yonenaga K, Yasui H, Kado H, et al. Myocardial retrograde infusion of blood cardioplegic solution protection by retrograde cardioplegia in arterial in pediatric patients undergoing heart operations. switch operation. Ann Thorac Surg 1990; 50: 238–42. J Thorac Cardiovasc Surg 1992; 104: 1349–55. Downloaded from https://academic.oup.com/tropej/article/52/1/59/1643726 by guest on 01 October 2021

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