SURGICAL OUTCOMES IN PATIENTS UNDERGOING A DOUBLE SWITCH OPERATION FOR CORRECTED TRANSPOSITION.

BACKGROUND: Congenitally corrected transposition of the great arteries (CC-TGA) is a rare and complex form of congenital heart disease. Results of physiologic repair proved disappointing due to late right ventricular dysfunction and/or tricuspid regurgitation. The current study was performed to evaluate surgical outcomes in patients undergoing a double switch for CC-TGA. METHODS: This was a retrospective review of 121 patients who underwent a double switch over a two-decade time frame (2002-2023). The median age of patients was 32 months. Forty-nine of 121 patients (40%) had undergone left ventricular retraining prior to double switch. RESULTS: Sixty-seven patients underwent an arterial switch whereas 54 underwent a Rastelli procedure. There were four in-hospital deaths (3.3%) including three who had a Rastelli procedure (5.6%) and one who had an arterial switch (1.5%). At a median follow-up of 30 months, there have been four late deaths (two Rastelli and two arterial switch). Combined early and late mortality was 9.3% for the Rastelli and 4.5% for arterial switch. Combined mortality was 2.0% for patients who required left ventricular retraining versus 9.7% for those who did not. For the 117 patients discharged from the hospital, 93% have normal or low normal left ventricular function and 96% have mild or less neo-aortic insufficiency. CONCLUSIONS: Surgical outcomes in patients undergoing a double switch procedure have been excellent both in the short- and mid-term. However, the Rastelli procedure was associated with a more than two-fold increase in mortality risk compared with the arterial switch.

Results of the Double Switch Operation in Patients Who Previously Underwent Left Ventricular Retraining.

BACKGROUND: Congenitally corrected transposition of the great arteries (CC-TGA) is a complex form of congenital heart disease that has numerous subtypes. While most patients with CC-TGA have a large ventricular septal defect (VSD) and pulmonary stenosis, there are some patients who have either no VSD or a highly restrictive VSD. These patients will require left ventricular (LV) retraining prior to double switch. The purpose of this study was to review our experience with the double switch procedure in patients who had previously undergone LV retraining. METHODS: This was a retrospective review of a single institution experience with the double switch procedure in patients who had undergone LV retraining (2002-present). RESULTS: Forty-five patients underwent double switch following LV retraining. Of these, 39 had an arterial switch with hemi-Mustard/bidirectional Glenn and six had a Senning. The median cross-clamp time was 135 min (range 71-272) and median bypass time was 202 min (range 140-430 min). Median hospital length of stay was eight days (range 4-108). There were no in-hospital deaths. Median duration of follow-up was 30 months (range 0-175). One patient subsequently underwent heart transplantation and died 65 months following double switch. At follow-up, 41 of the 44 survivors (93%) have normal or low normal LV function and 40 of the 44 survivors (91%) have no or trace mitral regurgitation. CONCLUSIONS: The data demonstrate early and mid-term survival of 100% and 97%. Ninety-three percent had preserved LV function. These results suggest that patients with CC-TGA who undergo LV retraining and double switch can have excellent clinical outcomes.

Cardiac magnetic resonance predictors for successful primary biventricular repair of unbalanced complete common atrioventricular canal.

BACKGROUND: Patients with unbalanced common atrioventricular canal can be difficult to manage. Surgical planning often depends on pre-operative echocardiographic measurements. We aimed to determine the added utility of cardiac MRI in predicting successful biventricular repair in common atrioventricular canal. METHODS: We conducted a retrospective cohort study of children with common atrioventricular canal who underwent MRI prior to repair. Associations between MRI and echocardiographic measures and surgical outcome were tested using logistic regression, and models were compared using area under the receiver operator characteristic curve. RESULTS: We included 28 patients (median age at MRI: 5.2 months). The optimal MRI model included the novel end-diastolic volume index (using the ratio of left ventricular end-diastolic volume to total end-diastolic volume) and the left ventricle-right ventricle angle in diastole (area under the curve 0.83, p = 0.041). End-diastolic volume index ≤ 0.18 and left ventricle-right ventricle angle in diastole ≤ 72° yield a sensitivity of 83% and specificity of 81% for successful biventricular repair. The optimal multimodality model included the end-diastolic volume index and the echocardiographic atrioventricular valve index with an area under the curve of 0.87 (p = 0.026). CONCLUSIONS: Cardiac MRI can successfully predict successful biventricular repair in patients with unbalanced common atrioventricular canal utilising the end-diastolic volume index alone or in combination with the MRI left ventricle-right ventricle angle in diastole or the echocardiographic atrioventricular valve index. A prospective cardiac MRI study is warranted to better define the multimodality characteristic predictive of successful biventricular surgery.

Congenitally Corrected Transposition of the Great Arteries: Fetal Diagnosis, Associations, and Postnatal Outcome: A Fetal Heart Society Research Collaborative Study.

Background Fetal diagnosis of congenitally corrected transposition of the great arteries (ccTGA) has been increasingly reported; however, predictors of clinical outcomes remain underexplored. We undertook a multicenter, retrospective study to investigate natural history, associated anomalies, and outcomes of fetal ccTGA. Methods and Results Fetuses with ccTGA diagnosed from January 2004 to July 2020 within 20 North American programs were included. Fetuses with severe ventricular hypoplasia thought to definitively preclude biventricular repair were excluded. We included 205 fetuses diagnosed with ccTGA at a median gestational age of 23 (interquartile range, 21-27) weeks. Genetic abnormalities were found in 5.9% tested, with extracardiac anomalies in 6.3%. Associated cardiac defects were diagnosed in 161 (78.5%), with atrioventricular block in 23 (11.3%). On serial fetal echocardiogram, 39% demonstrated a functional or anatomic change, most commonly increased tricuspid regurgitation (6.7%) or pulmonary outflow obstruction (11.1%). Of 194 fetuses with follow-up, 26 were terminated, 3 experienced fetal death (2 with atrioventricular block), and 165 were live-born. Of 158 with postnatal data (median follow-up 3.7 years), 10 (6.6%) had death/transplant before 1 year. On univariable analysis, fetal factors associated with fetal death or death/transplant by 1 year included ≥ mild tricuspid regurgitation, pulmonary atresia, aortic obstruction, fetal arrhythmia, and worsening hemodynamics on serial fetal echocardiogram (defined as worse right ventricular function, tricuspid regurgitation, or effusion). Conclusions Associated cardiac lesions and arrhythmias are common in fetal ccTGA, and functional changes commonly occur through gestation. Worse outcomes are associated with fetal tricuspid regurgitation (≥mild), any arrhythmia, pulmonary atresia, aortic obstruction, and worsening hemodynamics on serial echocardiograms. These findings can inform prenatal counseling and perinatal management planning.

Mid-gestational fetal placental blood flow is diminished in the fetus with congenital heart disease.

OBJECTIVE: Data suggest fetuses with congenital heart disease (CHD) have placental abnormalities. Their abnormal placental vasculature may affect fetal placental blood flow, which has not previously been explored. METHOD: We performed a retrospective cross-sectional study comparing umbilical venous volume flow (UVVF) of single ventricle, D-transposition of the great arteries, and tetralogy of Fallot fetuses with fetuses without CHD. UVVF and combined cardiac output (CCO) were calculated from fetal echocardiography and compared using t tests, χ2 and Fisher's exact tests. RESULTS: Mean gestational age and fetal weight were greater in CHD fetuses (26.5 weeks, 1119.4 g; n = 81, P < .001) compared to controls (23.1 weeks, 675 g; n = 170, P < .001). UVVF/fetal weight was nevertheless decreased among cases (99.8 vs 115.3 mL/min/kg, P < .001). Subgroup analysis of 20- to 25-week fetuses demonstrated no significant differences in case and control baseline characteristics. In CHD fetuses (n = 31) compared to controls (n = 144), absolute UVVF (50.8 vs 62.1 mL/min, P = .006), and UVVF/fetal weight (98.8 vs 118.5 mL/min/kg, P < .001) were decreased. Findings were similar in single ventricle (n = 24) and hypoplastic left heart syndrome (n = 14). CONCLUSION: Mid-gestational placental blood flow in CHD fetuses is decreased compared to controls. Further study is needed to explore the relationship between UVVF and placental pathology, and impact on outcomes.

Left Valvar Morphology Is Associated With Late Regurgitation in Atrioventricular Canal Defect.

BACKGROUND: Left atrioventricular valve regurgitation (LAVVR) after atrioventricular canal (AVC) repair remains a significant cause of morbidity. Papillary muscle arrangement may be important. To investigate the implications of left mural leaflet morphology, we examined anatomic characteristics of the LAVV to determine possible associations with postoperative LAVVR. METHODS: All patients with biventricular AVC repair at our institution between January 1, 2011, and December 31, 2016, with necessary imaging were retrospectively reviewed. We assessed papillary muscle structure and novel measures of the left mural leaflet from preoperative echocardiograms and the degree of LAVVR from the first and last available follow-up echocardiograms. Associations with degree of early and late postoperative LAVVR were assessed with t tests, analysis of variance, or χ2 or Fisher exact tests, and multivariable logistic regression. RESULTS: There were 58 of 156 patients (37%) with significant (moderate or severe) early postoperative LAVVR, and 30 of 93 (32%) had significant LAVVR after 6 or more months. Fewer patients with closely spaced or asymmetric papillary muscles had moderate or severe late LAVVR vs those with widely spaced papillary muscles (17% vs 40%, P = .019). Controlling for weight at operation, genetic syndromes, and bypass time, widely spaced papillary muscles increased the odds ratio for late LAVVR to 3.6 (P = .026). Larger mural leaflet area was also associated with late LAVVR on univariable (P = .019) and multivariable (P = .023) analyses. One-third of patients with significant late LAVVR had no significant early postoperative regurgitation. CONCLUSIONS: Mural leaflet and papillary muscle anatomy are associated with late LAVVR after AVC repair. Late regurgitation can develop in the absence of early LAVVR, suggesting different mechanisms.

A standardized imaging protocol improves quality and reduces practice variability in echocardiographic assessment of ventricular function by first-year pediatric cardiology fellows.

BACKGROUND: Echocardiography education for pediatric cardiology fellows has been a recent focus leading to the implementation of "boot camps." Less is described about continuing education through fellowship and improving image quality. We noticed practice variation in echocardiograms assessing ventricular function performed on nights and weekends. Thus, we implemented a standardized protocol and assessed its impact on imaging and reporting completeness. METHODS: We created an imaging protocol for the assessment of ventricular function in the acute setting. The protocol included demographic information, a list of images to be obtained, and the methods to quantify ventricular function. The protocol was explained to first-year fellows and distributed on an electronic quick reference card. Echocardiograms independently performed by first-year fellows during their first 4 months of on-call time were assessed pre- and postintervention using a standard rubric. RESULTS: Compliance with demographic reporting was high pre- and postintervention, but significantly improved after the standardized protocol (P < 0.001). Use of the protocol increased the median number of unique images obtained per echocardiogram from 13 to 17 (out of 23 required views, P < 0.001). Particularly improved was the performance of quantitative evaluations of function, including Simpson's method for left ventricular ejection fraction (four chamber: 40% vs 67%, P < 0.001; two chamber: 33% vs 67%, P < 0.001) and tricuspid annular plane systolic excursion (45% vs 80%, P < 0.001). CONCLUSIONS: The introduction of a standardized imaging protocol and its distribution to first-year fellows resulted in improvements in echocardiographic reporting completeness and increased the quality of information obtained by providing more quantitative assessments of ventricular function.

Repair of Total Anomalous Pulmonary Venous Connection: Risk Factors for Postoperative Obstruction.

BACKGROUND: Pulmonary venous obstruction after repair of total anomalous pulmonary venous connection (TAPVC) results in substantial morbidity and mortality. Risk factors for postoperative obstruction remain ambiguous. In addition, the existing literature has no standard definition for preoperative obstruction, making patient counseling difficult. METHODS: All patients undergoing repair of TAPVC at our institution from January 1, 2006, to October 23, 2017, were identified. The primary outcome was the development of postoperative obstruction, analyzed as a time-to-event outcome. Clinical information was extracted to assess risk factors. Degrees of preoperative obstruction were defined based on echocardiographic, catheterization, and clinical findings. Univariable and multivariable Cox proportional hazard regression methods were used to identify factors associated with the primary outcome. RESULTS: During the study interval, 119 patients underwent repair of TAPVC (40% single ventricle), and postoperative obstruction developed in 25 patients (21%). Risk factors associated with obstruction were heterotaxy syndrome, single-ventricle heart disease, additional procedures at the time of vein repair, mixed-type TAPVC, and preoperative obstruction. Having even mild preoperative obstruction (≥1.2 m/s by Doppler echocardiography) was predictive of postoperative obstruction. A multivariable model showed mixed-type TAPVC and the presence of preoperative obstruction were associated with a more than twofold greater hazard of obstruction. CONCLUSIONS: TAPVC in the setting of heterotaxy and a single ventricle remains challenging, with high rates of postoperative obstruction. Mixed-type TAPVC is an independent risk factor for postoperative obstruction, particularly in patients with isolated TAPVC. Even mild preoperative obstruction is a risk factor for postoperative obstruction. These results may help risk-stratify TAPVC patients.

Postoperative Obstruction of the Pulmonary Veins in Mixed Total Anomalous Pulmonary Venous Connection.

Total anomalous pulmonary venous connection (TAPVC) is a rare form of congenital heart disease in which the pulmonary veins drain by various pathways to the right atrium instead of the left atrium. Postoperative obstruction of the pulmonary veins is a known complication. Identifying risk factors for morbidity and mortality is important for counseling and monitoring. We describe a pattern of postoperative obstruction in a specific arrangement of mixed TAPVC. Five patients with a type of mixed TAPVC, namely, three pulmonary veins connecting to the coronary sinus and the left upper pulmonary vein (LUPV) connecting to the innominate vein, were identified over an 11-year period at our institution. Two additional patients with this TAPVC arrangement were cared for at our institution after having surgery at other institutions. Of these, one patient received only comfort care at birth due to other clinical issues. The six other patients underwent surgical unroofing of the coronary sinus. The anomalous LUPV was not addressed during the initial surgery in any of these cases. Following repair, one patient died from non-cardiac reasons. The remaining five patients all developed obstruction of the repaired pulmonary veins with decompression through the unrepaired LUPV, requiring surgical revision. Three patients underwent a second reoperation as well. Three of the six repaired patients also developed refractory atrial arrhythmias. This cohort suggests that this mixed TAPVC pattern predisposes patients to obstruction after surgical repair. Further investigation may aid pediatric cardiologists in risk-stratifying and counseling these patients. Alternative surgical approaches may need to be considered.

High-molecular-weight and total adiponectin levels and incident symptomatic peripheral artery disease in women: a prospective investigation.

BACKGROUND: Adiponectin is linked to reduced diabetes risk and may be antiatherogenic, yet clinical data show no consistent relationship with incident cardiovascular events, especially among women. To our knowledge, no prior prospective studies have evaluated adiponectin, including high-molecular-weight (HMW) adiponectin, and incident peripheral artery disease (PAD). METHODS AND RESULTS: We evaluated the relationship of total adiponectin, HMW adiponectin, and the HMW-to-total adiponectin ratio with incident symptomatic PAD in a prospective, nested case-control study conducted within the Women's Health Study (n=110 cases, n=230 controls, frequency matched in strata defined by 5-year age categories, smoking, fasting status, and follow-up time; median cohort follow-up=13.2 years). Baseline median levels of HMW and total adiponectin were significantly lower in women developing PAD than in those remaining event free (HMW: 3.3 versus 3.8 µg/mL, P=0.0005; total: 5.6 versus 7.4 µg/mL, P<0.0001). The ratio did not differ significantly between groups. Age-adjusted PAD odds ratios (95% confidence intervals) across tertiles were 1.0, 0.66 (0.39-1.13), and 0.40 (0.22-0.74) for HMW and 1.0, 0.74 (0.43-1.25), and 0.35 (0.18-0.65) for total adiponectin (P(trend)=0.004 and 0.001, respectively). Results were similar after adjustment for traditional cardiovascular risk factors, use of postmenopausal hormone therapy, high-sensitivity C-reactive protein, soluble intercellular adhesion molecule-1, leptin, hemoglobin A(1c), and fasting insulin (adjusted odds ratio and 95% confidence interval for HMW: 1.0, 0.62 [0.29-1.34], 0.30 [0.12-0.74]; total: 1.0, 0.46 [0.22-1.00], 0.30 [0.12-0.76]; P(trend)=0.01 for both). CONCLUSIONS: Total and HMW adiponectin are inversely associated with incident PAD among initially healthy women. These prospective data support a protective role for this adipokine in peripheral atherosclerosis development.

Determining and addressing obstacles to the effective use of long-lasting insecticide-impregnated nets in rural Tanzania.

BACKGROUND: The objective of this project was to achieve high, sustainable levels of net coverage in a village in rural Tanzania by combining free distribution of long-lasting insecticide-impregnated nets (LLINs) with community-tailored education. In Tanzania, malaria is the leading cause of morbidity and mortality. Although malaria bed nets have a well-established role in reducing disease burden, few rural households have access to nets, and effective use depends on personal practices and attitudes. METHODS: Five practices and attitudes inconsistent with effective LLIN use were identified from household interviews (n = 10). A randomized survey of villagers (n = 132) verified local prevalence of these practices and attitudes. Community leaders held an educational session for two members of every household addressing these practice and attitudes, demonstrating proper LLIN use, and emphasizing behaviour modification. Attendees received one or two LLINs per household. Surveys distributed three weeks (n = 104) and 15 months (n = 104) post-intervention assessed corrected practices and attitudes. Project efficacy was defined by correction of baseline practices and attitudes as well as high rates of reported daily net use, with statistical significance determined by chi-square test. RESULTS: Baseline interviews and surveys revealed incorrect practices and attitudes regarding 1) use of nets in dry season, 2) need to retreat LLINs, 3) children napping under nets, 4) need to repair nets, and 5) net procurement as a priority, with 53- 88.6% incorrect responses (11.4-47% correct responses). A three-week follow-up demonstrated 83-95% correct responses. Fifteen-month follow-up showed statistically significant (p < 0.01) corrections from baseline in all five practice and attitudes (39.4-93.3% correct answers). 89.4% of respondents reported using their nets every night, and 93.3% affirmed purchase of nets as a financial priority. CONCLUSIONS: Results suggest that addressing community-specific practices and attitudes prior to LLIN distribution promotes consistent and correct use, and helps change attitudes towards bed nets as a preventative health measure. Future LLIN distributions can learn from the paradigm established in this project.