Michael C. Mongé

Surgical reconstruction of peripheral pulmonary artery stenosis in Williams and Alagille syndromes

OBJECTIVES Peripheral pulmonary artery stenosis is a rare congenital heart defect frequently found in association with Williams and Alagille syndromes. Controversy exists regarding the optimal treatment of peripheral pulmonary artery stenosis, with most centers favoring catheter-based interventions. In contrast, we have preferentially used surgical reconstruction of peripheral pulmonary artery stenosis. The purpose of the present study was to review our experience with surgical reconstruction of peripheral pulmonary artery stenosis. METHODS We performed a retrospective review of patients who underwent surgical reconstruction of peripheral pulmonary artery stenosis. A total of 16 patients were identified: 7 had Williams syndrome, 6 had Alagille syndrome, and 3 had no identifiable syndrome. Detailed pulmonary angiography was performed in all patients to define stenoses at the main, branch, lobar, and segmental arterial levels. The mean preoperative right ventricular/left ventricular pressure ratio was 0.88 ± 0.07. The surgical approach was a median sternotomy with cardiopulmonary bypass. All peripheral stenoses were augmented with pulmonary artery homograft tissue. The median age at surgery was 14 months, and concomitant procedures were performed in 9 of the 16 patients. RESULTS There was 1 operative mortality (6%). The mean right ventricular/left ventricular pressure ratio decreased to 0.40 ± 0.04 postoperatively (P < .005), representing a 55% reduction compared with the preoperative values. The patients were followed up for a median of 5 years. No late mortality occurred and reoperation was not required. CONCLUSIONS The data have demonstrate that this comprehensive surgical approach to the treatment of peripheral pulmonary artery stenosis was associated with low early and no late mortality. Surgical reconstruction of the peripheral pulmonary artery stenosis resulted in a significant decrease in right ventricular pressure. We hypothesize that this reduction in right ventricular pressures will confer a long-term survival advantage for this cohort of patients.

Modified TandemHeart Ventricular Assist Device for Infant and Pediatric Circulatory Support

PURPOSE The development of pediatric ventricular assist device (VAD) circuits with lower flow ranges for infants and small children is ongoing. We present our results with modifying a readily available adult VAD to support the pediatric population. DESCRIPTION The TandemHeart VAD (CardiacAssist, Pittsburgh, PA) circuit was modified to include a variable restrictive recirculation shunt to permit lower flow ranges in small pediatric patients. EVALUATION Initial benchtop flow rates and pressures were studied. Hemolysis trials were performed using whole bovine blood to compare plasma-free hemoglobin levels between modified and unmodified VAD circuits. The modified VAD was surgically implanted in 7 piglets (6 to 14 kg) and which supported them for 4 hours. Levels of hemolysis did not increase and full hemodynamic support was achieved. The modified TandemHeart VAD with a recirculation shunt was subsequently implanted in 2 pediatric patients who were bridged to transplant successfully. CONCLUSIONS Because of its simplicity, availability, low prime volume, greater patient flow range, and lower cost, the modified TandemHeart VAD with a recirculation shunt should be considered as an alternative to extracorporeal membrane oxygenation and other pulsatile VADs in children.

Reoperation after Vascular Ring Repair

The majority of patients having surgical intervention for a vascular ring have resolution of their symptoms. However, 5% to 10% of these patients develop recurrent symptoms related either to airway or esophageal compression and may require reoperation. In our series of 300 patients with vascular rings, we performed a reoperation on 26 patients, not all of whom were originally operated on at our institution. The four primary indications for reoperation were Kommerell diverticulum (n = 18), circumflex aorta (n = 2), residual scarring (n = 2), and tracheobronchomalacia requiring aortopexy (n = 4). All patients undergoing reoperation have had preoperative evaluation with bronchoscopy and computed tomographic scanning (CT) with 3-dimensional reconstruction. Patients with dysphagia have had a barium esophagram and esophagoscopy. Patients with a Kommerell diverticulum have undergone resection of the diverticulum and transfer of the left subclavian artery to the left carotid artery. The aortic uncrossing procedure has been used in patients with a circumflex aorta. Aortopexy has been used to treat anterior compression of the trachea by the aorta. Results of these reinterventions have been successful in nearly all cases. Lessons learned from these reoperations can be applied to prevent the need for reoperation by properly selecting the correct initial operation. A dedicated team caring for these children consisting of medical imaging, otolaryngology, cardiovascular-thoracic surgery, and critical care is imperative.

Aortic Implantation of Anomalous Origin of the Left Coronary Artery From the Pulmonary Artery: Long-Term Outcomes

BACKGROUND Since 1989 all patients with anomalous origin of the left coronary artery from the pulmonary artery at our institution have been treated with aortic implantation. The purpose of this review was to assess the late outcomes of these patients, especially regarding left ventricular (LV) function and mitral valve insufficiency. METHODS Between 1989 and 2014, 36 patients had aortic implantation of anomalous origin of the left coronary artery from the pulmonary artery. Mean age at surgery was 2.5 ± 5.1 years (median, 0.5 years). Operative strategy included antegrade cold-blood cardioplegia, main pulmonary artery transection, aortic implantation with a large button of pulmonary artery, pulmonary reconstruction with fresh autologous pericardium, and prolonged postoperative inotropic and ventilator support. Mitral regurgitation and LV dysfunction were graded as 0 to 4 (0 = none, 1 = trivial, 1.5 = trivial-mild, 2 = mild, 2.5 = mild-moderate, 3 = moderate, 3.5 = moderate-severe, and 4 = severe). RESULTS Mean mitral regurgitation grade preoperatively was 2.95 ± 0.95. Mean LV dysfunction grade was 3.14 ± 1.27. Mean cross-clamp and cardiopulmonary bypass times were 49.1 ± 18 minutes (median, 48.5 minutes) and 147.5 ± 45 minutes (median, 139 minutes), respectively. There was no operative or late mortality. Four patients had delayed sternal closure. Mean duration of ventilator support was 11 ± 6.6 days (median, 9 days). Two patients required 3 and 6 days of postoperative extracorporeal mechanical circulatory support. Mean length of stay was 25 ± 18 days (median, 19 days). No patient has required reoperation for supravalvar pulmonary stenosis, coronary stenosis, or mitral valve repair or replacement. Late echocardiographic follow-up shows a mean mitral regurgitation grade of 1.67 ± 1.05 and a mean LV dysfunction grade of 0.23 ± 0.68. CONCLUSIONS Aortic implantation is our procedure of choice for patients with anomalous origin of the left coronary artery from the pulmonary artery. No patient required mitral valve repair or transplant. There was marked improvement of mitral regurgitation grade, return to essentially normal LV function, and no mortality during a 25-year period.

Successful Bridge‐to‐Transplant of Functionally Univentricular Patients With a Modified Continuous‐Flow Ventricular Assist Device

A continuous flow extracorporeal ventricular assist device (VAD) was modified to support functionally univentricular infants and children awaiting heart transplantation. A centrifugal VAD, designed to flow from 1.5 to 8 L/min, was used as a bridge-to-transplant in four patients with functionally univentricular circulation. A variable restrictive recirculation shunt permitted lower flow ranges in small patients. In hypoxic patients, an oxygenator was incorporated into the circuit. From 2012 to 2015, the modified VAD was placed in four patients with Glenn physiology. Age ranged from 0.97 to 6.98 years (median = 2.2 yrs). Body surface area ranged from 0.41 to 0.84 m2 (median = 0.54 m2 ). One patient was on extracorporeal membrane oxygenation prior to VAD. A recirculation shunt was used in three patients. Three patients required temporary use of an oxygenator for 4, 10, and 27 days. Median time on the VAD was 32.3 days (range = 23-43 days). A decrease in the cavopulmonary pressure was noted in all patients, as was a fall in the B-type natriuretic peptide. Three patients survived transplant and were discharged at 28-82 days post-transplantation. One patient died after 35 days of support. Two patients experienced major bleeding events. Two patients experienced cerebrovascular accidents, one major and one minor. The centrifugal VAD successfully supported palliated functionally univentricular patients awaiting heart transplantation. The modified recirculation shunt facilitated the successful support of patients in whom optimal flows were substantially lower than that recommended by the manufacturer. The continuous-flow VAD effectively decompressed the cavopulmonary system. The design allowed placement of an in-line oxygenator in hypoxic patients. Further investigation is required to decrease the thromboembolic events, and associated morbidity, in patients supported with this device.

Strategies for Ruptured Abdominal Aortic Aneurysms

Ruptured abdominal aortic aneurysms (AAAs) represent a lethal condition. The morbidity and mortality rates associated with open surgical repair remain alarmingly high and endoluminal exclusion may be a preferred alternative. Outlined in this review are suggested methods for expedient endovascular repair of ruptured AAAs that involve a multidisciplinary approach. Institutional comparative outcomes of open versus stent-graft repair are also reviewed in lieu of randomized trial data.

Modified Single Patch: Are We Still Worried About Subaortic Stenosis?

BACKGROUND When the modified single-patch technique for atrioventricular septal defect (AVSD) repair was introduced by Dr Benson Wilcox, there was concern that these patients might be at risk for late subaortic stenosis and left ventricular outflow tract obstruction (LVOTO). This review evaluated our modified single-patch population for LVOTO in the postoperative period. METHODS Between January 2000 and 2013, 77 infants underwent AVSD repair with a modified single-patch technique. Median age was 4.2 months, and median weight was 5 kg. Eight patients had a prior repair of coarctation of the aorta via left thoracotomy in the newborn period. RESULTS The median hospital stay was 10 days. No patient required a pacemaker. The mean and median follow-up times were 4.6 and 3.7 years, respectively. Only 2 patients (2.5%) required reoperation for LVOTO; both had prior repair of coarctation of the aorta (2 of 8 vs 0 of 69, p = 0.01). A discrete fibrous subaortic membrane developed in the first patient that required resection at 3 and 7 years after repair. The other patient had LVOTO from accessory chordae of the left atrioventricular valve and required mitral valve replacement 5 months after repair. One early death occurred at 4 months postoperatively due to liver failure related to hyperalimentation. CONCLUSIONS At intermediate term follow-up, LVOTO does not appear to be a significant postoperative issue after modified single-patch repair of AVSD. Coarctation of the aorta was the most significant predictor of late LVOTO after repair of AVSD with the modified single-patch technique.

Right pulmonary artery to left atrial fistula in a neonate: case report and review of the literature

A communication between the right pulmonary artery (RPA) and the left atrium is a rare congenital anomaly that presents with cyanosis and heart failure. We describe the surgical repair of an RPA to left atrial fistula using cardiopulmonary bypass in a neonate. Advanced imaging (computed tomography scan) guided the surgical approach. Although previous reports have associated a patent ductus arteriosus with high neonatal mortality, in our case, the ductus arteriosus was actually important for maintaining enough total pulmonary blood flow.

Brom Aortoplasty for Supravalvular Aortic Stenosis

Background: Controversy remains regarding the optimal surgical approach for children with supravalvular aortic stenosis (SVAS). Methods: Since 1997 we have used Brom three-patch aortoplasty for patients with SVAS. We prefer computed tomography (CT) imaging for preoperative evaluation rather than cardiac catheterization as it avoids the well-known morbidity of general anesthesia. The purpose of this study was to present our intermediate-term results of this strategy. Results: Twenty consecutive patients with SVAS were treated with Brom aortoplasty. Mean age was 3.7 ± 5.9 years (median, 1.5 years). Twelve patients had Williams syndrome. Ten patients had preoperative advanced medical imaging (seven CT, three magnetic resonance imaging) and did not have cardiac catheterization. Mean times for cardiopulmonary bypass and cross-clamp were 172 ± 29 minutes and 110 ± 21 minutes, respectively. Ten patients had simultaneous pulmonary artery stenosis patching. Median length of stay was seven days. There was no operative or late mortality. Mean follow-up was 6 ± 5 years. There were no reoperations on the aortic root. Fifteen patients had mild or less aortic insufficiency (AI) and two had moderate AI. One patient who had infant balloon dilation of the aortic valve and postoperative subacute bacterial endocarditis had moderate-to-severe AI and aortic stenosis (AS). One patient had moderate residual SVAS; all others had no AS. No patients had late coronary insufficiency. Conclusion: Brom aortoplasty promotes restoration of normal aortic root geometry and relief of coronary ostial stenosis, which is important in preventing myocardial ischemia. Computed tomography imaging is our preferred diagnostic modality. Intermediate-term outcomes are excellent with no recurrent SVAS, coronary events, or reoperations on the aortic valve.

Associations Between Unplanned Cardiac Reinterventions and Outcomes After Pediatric Cardiac Operations

BACKGROUND After pediatric heart operations, we sought to determine the incidence of unplanned cardiac reinterventions during the same hospitalization, assess risk factors for these reinterventions, and explore associations between reinterventions and outcomes. We hypothesized that younger patients undergoing more complex operations would be at greater risk for unplanned cardiac reinterventions and that operative mortality and postoperative length of stay (PLOS) would be greater in patients who undergo reintervention than in those who do not. METHODS Patients aged 18 years or younger in The Society of Thoracic Surgeons Congenital Heart Surgery Database (January 2010 to June 2015) were included. We used multivariable regression to evaluate risk factors for unplanned cardiac reintervention (operation or therapeutic catheterization) and associations of reintervention with operative mortality and PLOS. RESULTS Of 84,404 patients (117 centers), 21% were neonates and 36% infants. An unplanned cardiac reintervention was performed in 5.4% of patients, including 11.8% of neonates, 5.2% of infants, and 2.8% of children. Independent risk factors for unplanned reintervention included presence of noncardiac anomalies/genetic syndromes, nonwhite race, younger age, lower weight among neonates and infants, prior cardiothoracic operations, preoperative mechanical ventilation, other Society of Thoracic Surgeons preoperative risk factors, and higher Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery Mortality Category (adjusted p < 0.001 for all). Unplanned reintervention was a risk factor for operative mortality (adjusted odds ratio, 5.3; 95% confidence interval, 4.8 to 5.8; p < 0.001) and longer PLOS (adjusted relative risk, 2.3; 95% confidence interval, 2.2 to 2.4; p < 0.001). CONCLUSIONS Unplanned cardiac reinterventions are not rare, particularly in neonates, and are independently associated with operative mortality and increased PLOS. Patients at greater risk may be identified preoperatively, presenting opportunities for quality improvement.