Management of Pulmonary Vascular Disease Associated with Congenital Left to Right Shunts: A Single Center Experience.

OBJECTIVE: To describe the course and outcomes of children under 18 with left-to-right (LR) shunts and pulmonary arterial hypertension (PAH) undergoing one of two management approaches: PAH treatment prior to LR shunt repair (Treat First) and LR shunt repair first, with or without subsequent PAH treatment (Repair First). METHODS: Retrospective single center study, conducted from September 2015 to September 2021, of children LR shunts and PAH (defined as indexed pulmonary vascular resistance (PVRi) ≥ 4WU*m2) but without Eisenmenger physiology. Patient characteristics, longitudinal hemodynamics data, PAH management, LR shunt repair, and outcomes were reviewed. RESULTS: Of 768 patients evaluated for LR shunt closure, 51 (6.8%) had LR shunt associated PAH [median age 1.1 (0.37,5) years, median PVRi 6 (5.2,8.7) WU*m2]. Of the "Treat First" group (n=33, 65%), 27 (82%) underwent LR shunt closure and 6 (18%) did not respond to PAH therapy and did not undergo LR shunt closure. In the "Repair First" group (n=18, 35%), 12 (67%) received PAH therapy and 6 (33%) did not. Mortality rates were 6% in "Treat First" and 11% in "Repair First", follow-up of 3.4 and 2.5 years, respectively. After LR shunt closure, there was no significant change in PVRi over a median follow-up of 2 years after surgery (p=0.77). CONCLUSIONS: In children with LR shunts and associated PAH, treatment with PAH-targeted therapy before defect repair does not appear to endanger the subjects and may have some benefit. The response to PAH-targeted therapy before shunt closure persists 2-3 years post-closure, providing valuable insights into the long-term management of these patients.

Atrioventricular block after congenital heart surgery: Analysis from the Pediatric Cardiac Critical Care Consortium.

OBJECTIVES: Our primary aims were to describe the contemporary epidemiology of postoperative high-grade atrioventricular block (AVB), the timing of recovery and permanent pacemaker (PPM) placement, and to determine predictors for development of and recovery from AVB. METHODS: Patients who underwent congenital heart surgery from August 2014 to June 2017 were analyzed for AVB using the Pediatric Cardiac Critical Care Consortium registry. Predictors of AVB with or without PPM were identified using multinomial logistic regression. We used these predictors to model the probability of PPM for the subgroup of patients with intraoperative complete AVB. RESULTS: We analyzed 15,901 surgical hospitalizations; 422 (2.7%) were complicated by AVB and 162 (1.0%) patients underwent PPM placement. In patients with transient AVB, 50% resolved by 2 days, and 94% resolved by 10 days. In patients who received a PPM, 50% were placed by 8 days and 62% were placed by 10 days. Independent risk factors associated with PPM compared with resolution of AVB were longer duration of cardiopulmonary bypass (relative risk ratio, 1.04; P = .023) and a high-risk operation (relative risk ratio, 2.59; P < .001). Among patients with complete AVB originating in the operating room, those with the highest predicted probability of PPM had a PPM placed only 77% of the time. CONCLUSIONS: In this cohort, postoperative AVB complicated almost 3% of congenital heart surgery cases and 1% of patients underwent PPM placement. Because almost all patients (94%) with transient AVB had resolution by 10 days, our results suggest there is limited benefit to delaying PPM placement beyond that time frame.

Exploring the Role of Polycythemia in Patients With Cyanosis After Palliative Congenital Heart Surgery.

OBJECTIVES: To understand the relationship between polycythemia and clinical outcome in patients with hypoplastic left heart syndrome following the Norwood operation. DESIGN: A retrospective, single-center cohort study. SETTING: Pediatric cardiovascular ICU, university-affiliated children's hospital. PATIENTS: Infants with hypoplastic left heart syndrome admitted to our medical center from September 2009 to December 2012 undergoing stage 1/Norwood operation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Baseline demographic and clinical information including first recorded postoperative hematocrit and subsequent mean, median, and nadir hematocrits during the first 72 hours postoperatively were recorded. The primary outcomes were in-hospital mortality and length of hospitalization. Thirty-two patients were included in the analysis. Patients did not differ by operative factors (cardiopulmonary bypass time and cross-clamp time) or traditional markers of severity of illness (vasoactive inotrope score, lactate, saturation, and PaO2/FIO2 ratio). Early polycythemia (hematocrit value > 49%) was associated with longer cardiovascular ICU stay (51.0 [± 38.6] vs 21.4 [± 16.2] d; p < 0.01) and total hospital length of stay (65.0 [± 46.5] vs 36.1 [± 20.0] d; p = 0.03). In a multivariable analysis, polycythemia remained independently associated with the length of hospitalization after controlling for the amount of RBC transfusion (weight, 4.36 [95% CI, 1.35-7.37]; p < 0.01). No difference in in-hospital mortality rates was detected between the two groups (17.6% vs 20%). CONCLUSIONS: Early polycythemia following the Norwood operation is associated with longer length of hospitalization even after controlling for blood cell transfusion practices. We hypothesize that polycythemia may be caused by hemoconcentration and used as an early marker of capillary leak syndrome.

Ventricular lead redundancy to prevent cardiovascular events and sudden death from lead fracture in pacemaker-dependent children.

BACKGROUND: Children requiring a permanent epicardial pacemaker (PM) traditionally have a single lead placed on the right ventricle. Lead failure in pacemaker-dependent (PMD) children, however, can result in cardiovascular events (CVEs) and death. OBJECTIVE: The purpose of this study was to determine if redundant ventricular lead systems (RVLS) can safeguard against CVE and death in PMD children. METHODS: This was a single-center study of PMD patients undergoing placement of RVLS from 2002-2013. Patients ≤21 years of age who were PMD were included. Patients with a biventricular (BiV) system placed for standard resynchronization indications were excluded. RVLS patients were compared to PMD patients with only a single pacing lead on the ventricle (SiV). RESULTS: Seven hundred sixty-nine patients underwent PM/implantable cardioverter-defibrillator placement with 76 BiV implants; 49 patients (6%) were PMD. Thirteen patients underwent implantation of an RVLS. There was no difference between the RVLS group (n = 13) and SiV PMD control group (n = 24) with regard to age (RVLS 9.5 ± 5.8 years vs SiV 9.4 ± 6.7 years, P = .52), weight (RVLS 38.2 ± 32.6 kg vs SiV 35.2 ± 29.3 kg, P = .62), indication for pacing, procedural complications, or time to follow-up. There were 2 lead fractures (17%) in the RVLS group (mean follow-up 3.8 ± 2.9 years), with no deaths or presentations with CVE. The SiV control group had 3 lead fractures (13%) (mean follow-up 2.8 ± 2.9 years), with no deaths, but all 3 patients presented with CVE and required emergent PM placement. CONCLUSION: RVLS systems should be considered in children who are PMD and require permanent epicardial pacing. BiV pacing and RVLS may decrease the risk of CVE in the event of lead failure in PMD patients.

Tetralogy of Fallot: aorto-pulmonary collaterals and pulmonary arteries have distinctly different transcriptomes.

BACKGROUND: Tetralogy of Fallot patients with pulmonary atresia (TOF/PA) present a pulmonary blood supply directly from aortic collateral arteries. Major aorto-pulmonary collateral arteries (MAPCAs) present substantial clinical and surgical management challenges. Surgical operations to reestablish and promote further development of a pulmonary arterial connection preferentially utilize MAPCAs for reconstruction of central pulmonary arteries. However, the propensity of some MAPCAs to develop stenosis rather than growth may impair the response to reconstructions. METHODS: Probe sets prepared from MAPCAs, PA, and aorta mRNA were used to interrogate human genome microarrays. We compared expression differences between pairs of the three vessels to determine whether MAPCAs display distinct expression patterns. RESULTS: Functional clustering analysis identified differences in gene expression, which were further analyzed by gene ontology classification. A subset of highly regulated genes was validated using quantitative PCR. Expression differences among vessel types were observed for multiple gene classes. Of note, we observed that MAPCAs differentially express several genes at much higher levels than either PA or aorta. CONCLUSION: MAPCAs differ from PA or aorta by significantly altered levels in gene expression, suggesting a transcriptional basis for their physiology that will guide a further understanding of the pathobiology of MAPCAs and TOF.

Surgical outcomes for patients with pulmonary atresia/major aortopulmonary collaterals and Alagille syndrome.

OBJECTIVES: Pulmonary atresia with major aortopulmonary collateral arteries (PA/MAPCAs) is a complex congenital heart defect that has undergone significant advances in treatment over the past 15 years. A small subset of patients with PA/MAPCAs have associated Alagille syndrome, which can have an adverse impact on many other organ systems. The purpose of this study was to review our institutional outcomes for the surgical patients with PA/MAPCAs and Alagille syndrome. METHODS: This was a retrospective review of patients with PA/MAPCA's and Alagille who underwent surgical reconstruction from November 2001 to August 2011. Fifteen patients were identified in our data base. Thirteen had pulmonary atresia with ventricular septal defect (PA/VSD) and two had pulmonary atresia with intact ventricular septum (PA-IVS). RESULTS: There has been no early or late mortality in this cohort of 15 patients with PA/MAPCA' and Alagille syndrome. The patients have undergone a total of 38 cardiac surgical procedures. Ten of the 13 patients with PA/VSD have achieved complete repair, including unifocalization, a right ventricle to pulmonary artery conduit and closure of all intra-cardiac shunts. The three unrepaired patients with PA/VSD remain potential candidates for eventual complete repair, while the two patients with PA-IVS remain viable candidates for a single ventricle pathway. The patients in this series have also undergone 12 major non-cardiac procedures. CONCLUSIONS: The data demonstrate that surgical reconstruction of PA/MAPCAs can be successfully achieved in patients with Alagille syndrome. The longer-term prognosis remains guarded on the basis of the multi-organ system involvement of Alagille syndrome.

Morphological studies of pulmonary arteriovenous shunting in a lamb model of superior cavopulmonary anastomosis.

We sought to identify and characterize the abnormal vascular structures responsible for pulmonary arteriovenous shunting following the Glenn cavopulmonary shunt. Superior cavopulmonary shunt is commonly performed as part of the staged pathway to total cavopulmonary shunt to treat univentricular forms of congenital heart disease, however, clinically significant pulmonary arteriovenous malformations develop in some patients after the procedure. The causes of pulmonary arteriovenous malformations and other pulmonary vascular changes that occur after cavopulmonary shunt are not known. Using a juvenile lamb model of superior cavopulmonary anastomosis that reliably produces pulmonary arteriovenous malformations, we performed echocardiography and morphological analyses to determine the anatomic site of shunting and to identify the vascular structures involved. Pulmonary arteriovenous shunting was identified by contrast echocardiography in all surviving animals (n = 40) following superior cavopulmonary anastomosis. Pulmonary vascular corrosion casts revealed abnormal tortuous vessels joining pulmonary arteries and veins in cavopulmonary shunt animals but not control animals. In conclusion, unusual channels that bridged pulmonary arteries and veins were identified. These may represent the vascular structures responsible for arteriovenous shunting following the classic Glenn cavopulmonary shunt. Detailed analysis of these structures may elucidate factors responsible for their development.

Surgical management of coronary artery arising from the wrong coronary sinus, using standard and novel approaches.

OBJECTIVES: Patients with a coronary artery arising from the wrong sinus are susceptible to ischemia and sudden death. Risk is higher when the artery courses interarterially--between the pulmonary artery and aorta--has an intramural course, or has an abnormal orifice. In single coronary ostium without intramural course, unroofing and coronary reimplantation are inappropriate, and coronary artery bypass grafting is suboptimal. For this variant, we have devised pulmonary artery translocation. METHODS: A retrospective review of 18 patients undergoing repair between January 1999 and March 2005 was performed. Mean age was 8.1 years (range 6 weeks-16 years). All anomalous arteries coursed interarterially. Ten patients had a right coronary artery from the left coronary sinus; 8 had a left coronary artery from the right sinus. Eleven had an intramural course, and 4 had a single coronary ostium without an intramural course. Ten (56%) patients had symptoms: chest pain (9/10), syncope (3/10), or dyspnea (2/10). Repair was implemented by unroofing (n = 11), reimplantation (n = 3), or pulmonary artery translocation (1 lateral, 3 anterior). All patients were followed up clinically and echocardiographically. RESULTS: At a mean of 2.2 years (2 weeks-5 years), there was no mortality. Symptoms improved and function remained normal in all but 1 patient. He had sustained multiple infarcts in the anomalous artery's distribution and required transplantation despite repair. CONCLUSIONS: Repair is indicated in all patients with coronary insufficiency and in asymptomatic patients with high-risk morphologic abnormalities. We recommend unroofing when an intramural component (or slit-like orifice) is present, reimplantation for separate ostia without an intramural course, and pulmonary artery translocation for single ostium without an intramural course. Coronary artery bypass grafting is thus avoided.

Intermediate term follow-up of the end-to-side aortic anastomosis for coarctation of the aorta.

BACKGROUND: Classic techniques for repairing coarctation of the aorta, especially in neonates, have a significant incidence of recurrent obstruction. By connecting the descending aorta to the proximal aortic arch, the end-to-side aortic anastomosis isolates hypoplastic distal arch and encroaching ductal tissue from the anastomotic site. METHODS: Follow-up data were available for 88 patients (54 male) who underwent an end-to-side aortic anastomosis from November 1992 until November 1999. The median postoperative follow-up was 1.9 years (range, 0.1 to 6.3 years). Fifty-four patients were corrected as neonates. Thirty-four patients were operated on out of the neonatal period (> 1 month of age). A systolic blood pressure gradient > or = 20 mm Hg and a Doppler flow velocity > or = 2.5 ms across the area of repair were considered a recurrent obstruction. RESULTS: No patients in the pediatric group had a recurrent obstruction. In the neonatal group, 3 patients (5.5%) had recurrent obstruction. Of those, 2 patients had a reintervention performed; one reintervention was a balloon angioplasty and the other one was a reoperation. Kaplan-Meier analysis of the neonatal group revealed a 95.8% freedom from reintervention at 1 and 2 years. CONCLUSIONS: The end-to-side aortic anastomosis is an effective repair for coarctation of the aorta. Even when performed in the neonatal period, recurrence of coarctation is rare.