Preoperative Hemodynamics Impact the Benefit of Fenestration on Fontan Postoperative Length of Stay.

BACKGROUND: Utilization of Fontan fenestration varies considerably by center. OBJECTIVES: Using a multicenter Pediatric Heart Network dataset linking surgical and preoperative hemodynamic variables, the authors evaluated factors associated with use of Fontan fenestration and the impact of fenestration on post-Fontan length of stay (LOS). METHODS: Patients 2 to 6 years old at Fontan surgery from 2010 to 2020 with catheterization<1 year prior were included. Factors associated with fenestration were evaluated using multivariable logistic regression adjusting for key covariates. Restrictive cubic spline analysis was used to evaluate potential cut-points for hemodynamic variables associated with longer postoperative LOS stratified by fenestration with multivariable linear regression to evaluate the magnitude of effect. RESULTS: Fenestration was used in 465 of 702 patients (66.2%). Placement of a fenestration was associated with center (range 27%-93% use, P < 0.0001) and Fontan type (OR: 14.1 for lateral tunnel vs extracardiac conduit, P < 0.0001). No hemodynamic variable was independently associated with fenestration. In a multivariable linear model adjusting for center, a center-fenestration interaction, prematurity, preoperative mean pulmonary artery pressure (mPAP), and cardiac index, fenestration was associated with shorter hospital LOS after Fontan (P = 0.0024). The benefit was most pronounced at mPAP ≥13 mm Hg (median LOS: 9 vs 12 days, P = 0.001). CONCLUSIONS: There is wide center variability in use of Fontan fenestration that is not explained by preoperative hemodynamics. Fenestration is independently associated with shorter LOS, and those with mPAP ≥13 mm Hg at pre-Fontan catheterization benefit the most. We propose this threshold as minimal criteria for fenestration.

Contemporary transesophageal echocardiography practice patterns among paediatric cardiology centres in the United States and Canada.

OBJECTIVE: To characterise transesophageal echocardiography practice patterns among paediatric cardiac surgical centres in the United States and Canada. METHODS: A 42-question survey was sent to 80 echocardiography laboratory directors at paediatric cardiology centres with surgical programmes in the United States and Canada. Question domains included transesophageal echocardiography centre characteristics, performance and reporting, equipment use, trainee participation, and quality assurance. RESULTS: Fifty of the 80 centres (62.5%) responded to the survey. Most settings were academic (86.0%) with 42.0% of centres performing > 350 surgical cases/year. The median number of transesophageal echocardiograms performed/cardiologist/year was 50 (26, 73). Pre-operative transesophageal echocardiography was performed in most surgical cases by 91.7% of centres. Transesophageal echocardiography was always performed by most centres following Norwood, Glenn, and Fontan procedures and by < 10% of centres following coarctation repair. Many centres with a written guideline allowed transesophageal echocardiography transducer use at weights below manufacturer recommendations (50.0 and 61.1% for neonatal and paediatric transducers, respectively). Most centres (36/37, 97.3%) with categorical fellowships had rotations which included transesophageal echocardiography participation. Large surgical centres (>350 cases/year) had higher median number of transesophageal echocardiograms/cardiologist/year (75.5 [53, 86] versus 35 [20, 52], p < 0.001) and more frequently used anaesthesia for diagnostic transesophageal echocardiography ≥ 67% of time (100.0 versus 62.1%, p = 0.001). CONCLUSIONS: There is significant variability in transesophageal echocardiography practice patterns and training requirements among paediatric cardiology centres in the United States and Canada. Findings may help inform programmatic decisions regarding transesophageal echocardiography expectations, performance and reporting, equipment use, trainee involvement, and quality assurance.

Counseling Practices for Fetal Hypoplastic Left Heart Syndrome.

While counseling parents of a fetus diagnosed with hypoplastic left heart syndrome (HLHS), pediatric cardiologists play a critical role in shaping a family's expectations for the months and years to come. However, techniques for the most effective counseling practices have not been studied, and significant variation among physicians is likely present. Web-based survey of pediatric cardiologists that perform fetal echocardiography using snowball sampling. 201 physicians responded (61% male, 81% from academic centers, and 95% from the U.S.), with an average experience of 12 years. The majority of respondents (73%) typically received initial referrals for HLHS between 20 and 24 weeks of gestation. Most physicians counsel families alone (54%), while others counsel with a nurse (35%), social worker (12%), and/or maternal-fetal medicine colleague (15%). Termination of pregnancy was discussed by 79% of respondents, although 15% did not know their state's legal limit for termination. While initial counseling sessions routinely described the typical earlier ramifications of HLHS, many long-term sequelae of the disease were not commonly discussed. Content of counseling was affected by region of the country, but not by practice setting, experience, or fetal volume. Respondents identified multiple barriers that limited their counseling practices. Our data suggest that current counseling practices often fail to cover important information. Perceived barriers to a full discourse on long-term sequelae of HLHS are common and may lead to a disconnect between reality and a family's understanding of the natural history of palliated HLHS. Opportunities to improve counseling practices exist, and there may be benefits to gain from more formal training.

Maladaptive aortic properties after the Norwood procedure: An angiographic analysis of the Pediatric Heart Network Single Ventricle Reconstruction Trial.

OBJECTIVES: Aortic arch reconstruction in children with single ventricle lesions may predispose to circulatory inefficiency and maladaptive physiology leading to increased myocardial workload. We sought to describe neoaortic anatomy and physiology, risk factors for abnormalities, and impact on right ventricular function in patients with single right ventricle lesions after arch reconstruction. METHODS: Prestage II aortic angiograms from the Pediatric Heart Network Single Ventricle Reconstruction trial were analyzed to define arch geometry (Romanesque [normal], crenel [elongated], or gothic [angular]), indexed neoaortic dimensions, and distensibility. Comparisons were made with 50 single-ventricle controls without prior arch reconstruction. Factors associated with ascending neoaortic dilation, reduced distensibility, and decreased ventricular function on the 14-month echocardiogram were evaluated using univariate and multivariable logistic regression. RESULTS: Interpretable angiograms were available for 326 of 389 subjects (84%). Compared with controls, study subjects more often demonstrated abnormal arch geometry (67% vs 22%, P < .01) and had increased ascending neoaortic dilation (Z score 3.8 ± 2.2 vs 2.6 ± 2.0, P < .01) and reduced distensibility index (2.2 ± 1.9 vs 8.0 ± 3.8, P < .01). Adjusted odds of neoaortic dilation were increased in subjects with gothic arch geometry (odds ratio [OR], 3.2 vs crenel geometry, P < .01) and a right ventricle-pulmonary artery shunt (OR, 3.4 vs Blalock-Taussig shunt, P < .01) but were decreased in subjects with aortic atresia (OR, 0.7 vs stenosis, P < .01) and those with recoarctation (OR, 0.3 vs no recoarctation, P = .04). No demographic, anatomic, or surgical factors predicted reduced distensibility. Neither dilation nor distensibility predicted reduced right ventricular function. CONCLUSIONS: After Norwood surgery, the reconstructed neoaorta demonstrates abnormal anatomy and physiology. Further study is needed to evaluate the longer-term impact of these features.

Malignant bileaflet mitral valve prolapse syndrome in patients with otherwise idiopathic out-of-hospital cardiac arrest.

OBJECTIVES: The aim of this study was to investigate the prevalence of mitral valve prolapse (MVP) and its association with ventricular arrhythmias in a cohort with "unexplained" out-of-hospital cardiac arrest. BACKGROUND: Ventricular arrhythmias are an important cause of sudden unexpected death in the young. The role of MVP in sudden unexpected death remains controversial. METHODS: Of 1,200 patients evaluated between July 2000 and December 2009 in the Mayo Clinic's Long QT Syndrome/Genetic Heart Rhythm Clinic, all 24 (16 women, median age 33.5 years) with idiopathic out-of-hospital cardiac arrest (i.e., negative for ischemia, cardiomyopathy, and channelopathy) were reviewed. RESULTS: All 24 patients had implantable cardioverter-defibrillators (ICDs). Out-of-hospital cardiac arrest was the sentinel event in 22 (92%). Bileaflet MVP was found in 10 (42%). Compared with patients with normal mitral valves, patients with bileaflet MVP: 1) were over-represented by women (9 of 10 [90%] vs. 7 of 14 [50%], p = 0.04); 2) had a higher prevalence of biphasic or inverted T waves (7 of 9 [77.8%] vs. 4 of 14 [29%], p = 0.04); and 3) on Holter interrogation had higher prevalence of ventricular bigeminy (9 of 9 [100%] vs. 1 of 10 [10%], p < 0.0001), ventricular tachycardia (7 of 9 [78%] vs. 1 of 10 [10%], p = 0.006), and premature ventricular contractions originating from the outflow tract alternating with the papillary muscle or fascicular region (7 of 9 [78%] vs. 2 of 10 [20%], p = 0.02). Over a median 1.8 years (range: 0.1 to 11.9 years) from ICD placement, 13 of 24 patients (54%) received appropriate ventricular fibrillation-terminating ICD shocks. Only bileaflet MVP was associated with ventricular fibrillation recurrences requiring ICD therapy on follow-up (logistic regression odds ratio: 7.2; 95% confidence interval: 1.1 to 48; p = 0.028). CONCLUSIONS: The authors describe a "malignant" subset of patients with MVP who experienced life-threatening ventricular arrhythmias. This phenotype is characterized by bileaflet MVP, female sex, and frequent complex ventricular ectopic activity, including premature ventricular contractions of the outflow tract alternating with papillary muscle or fascicular origin.

Interactions between opioids and cocaine on locomotor activity in rats: influence of an opioid's relative efficacy at the mu receptor.

RATIONALE: Cocaine and mu opioid agonists increase central dopamine concentrations and produce robust interactions at both neurochemical and behavioral levels. Although the interactions between cocaine and high-efficacy mu opioids have been well characterized, the interactions between cocaine and lower efficacy opioids have not been as extensively examined. OBJECTIVE: The purpose of this study was to examine the interactions between cocaine and opioids possessing a range of relative efficacy at the mu receptor. METHODS: Male, Long-Evans rats were habituated to an open-field, locomotor activity chamber, and the effects of cocaine and various opioids were tested under a cumulative dosing procedure. In this procedure, a selected dose of an opioid was administered during the first component of a session, with increasing doses of cocaine administered during subsequent components. RESULTS: When administered alone, cocaine produced dose-dependent increases in locomotor activity that was stable across 5 weeks of behavioral testing. The high-efficacy mu opioid levorphanol, and the low-efficacy opioids buprenorphine, butorphanol, nalbuphine and (-)-pentazocine, dose-dependently enhanced the effects of cocaine at doses that did not alter locomotor activity when administered alone. In contrast, the opioid antagonist naloxone, and to a lesser extent, the kappa opioid spiradoline attenuated the effects of cocaine at doses that did not alter locomotor activity when administered alone. Across an extensive dose range, the low-efficacy opioid nalorphine failed to alter cocaine's locomotor-activating effects. CONCLUSIONS: These data suggest that low-efficacy opioids possessing significant mu-agonist activity (e.g. buprenorphine, butorphanol, nalbuphine, (-)-pentazocine) may potentiate the effects of cocaine in a manner similar to that typically observed with high-efficacy mu opioids.