Left ventricular remodeling following septal myectomy in hypertrophic obstructive cardiomyopathy.

Objectives: The purpose of this study is to determine whether or not left ventricular remodeling can be induced after septal myectomy in patients with obstructive hypertrophic cardiomyopathy, and if so, how it occurs, using gated cardiac computed tomography. Methods: Fifty patients with hypertrophic obstructive cardiomyopathy who underwent septal myectomy along the septal band between March 2016 and July 2020 were retrospectively reviewed. Recent consecutive 19 patients underwent postoperative cardiac computed tomography. In these patients, volumes of the septal band and thickness of 17 left ventricular myocardial segments were measured to determine the changes after surgery. Results: The resection volume predicted by preoperative computed tomography and the actual resection volume were 6.7 ± 3.3 mL and 6.4 ± 2.7 mL. In-hospital mortality was 0%. Moderate or greater mitral valve regurgitation and systolic anterior motion decreased from 56% to 6% and 86% to 6%, respectively. Median preoperative ventricular septal thickness and left ventricular outflow tract pressure gradient at rest decreased from 20.0 mm (interquartile range, 17.0-24.0 mm) and 74.0 mm Hg (interquartile range, 42.5-92.5 mm Hg) to 14.0 mm (interquartile range, 11.5-16.0 mm) and 15.5 mm Hg (interquartile range, 12.1-21.5 mm Hg), respectively. Postoperative computed tomography confirmed a reduction in septal band volume of 5.7 ± 2.8 mL. Total left ventricular myocardial volume was reduced by 12.9 ± 8.8 mL, which exceeded the volume reduction of the resected septal band. All segments except the basal inferior and basal inferolateral regions showed a significant decrease in wall thickness by a median of 6.4%. Conclusions: Properly performed septal myectomy may induce remodeling of the entire left ventricle, not just the resected area.

Cardiac MRI predictors of adverse outcomes in adults with a systemic right ventricle.

AIMS: Predicting risk in individuals with a systemic right ventricle (SRV) remains difficult. We assessed the value of cardiac MRI (CMR) for predicting death, heart transplantation (HT), or need for a ventricular assist device (VAD) in adults with D-transposition of the great arteries (DTGA) post Mustard/Senning and in adults with congenitally corrected transposition of the great arteries (ccTGA) at two large academic centres. METHODS AND RESULTS: Between December 1999 and November 2020, 158 adult patients with an SRV underwent CMR. Indexed right ventricular end-diastolic volume (RVEDVI), indexed right ventricular end-systolic volume (RVESVI), right ventricular ejection fraction (RVEF), and right ventricular mass (RV mass) were determined by a core laboratory. Receiver operating curves, area under the curve (AUC), and cut-points maximizing sensitivity and specificity for the endpoint for each CMR parameter were calculated. Over a median of 8.5 years, 21 patients (13%) met a combined endpoint of HT referral, VAD, or death. Each CMR parameter was significantly associated with the endpoint in both cohorts. The AUCs for RVEDVI, RVESVI, RVEF, and RV mass to predict the endpoint were 0.93, 0.90, 0.73, and 0.84 for DTGA and 0.76, 0.74, 0.71, and 0.74 for ccTGA, respectively. Optimized cut-points for RVEDVI were calculated for DTGA and ccTGA and were 132 and 126 mL/m2 , respectively. RVEDVI cut-points were simplified to 130 mL/m2 for survival analysis, which was significantly associated with survival in both cohorts. CONCLUSIONS: Cardiac MRI parameters are associated with an increased risk of death, HT, or VAD in patients with an SRV and should be considered to facilitate risk stratification.

Predicting the development of adverse cardiac events in patients with hypertrophic cardiomyopathy using machine learning.

BACKGROUND: Only a subset of patients with hypertrophic cardiomyopathy (HCM) develop adverse cardiac events - e.g., end-stage heart failure, cardiovascular death. Current risk stratification methods are imperfect, limiting identification of high-risk patients with HCM. Our aim was to improve the prediction of adverse cardiac events in patients with HCM using machine learning methods. METHODS: We applied modern machine learning methods to a prospective cohort of adults with HCM. The outcome was a composite of death due to heart failure, heart transplant, and sudden death. As the reference model, we constructed logistic regression model using known predictors. We determined 20 predictive characteristics based on random forest classification and a priori knowledge, and developed 4 machine learning models. Results Of 183 patients in the cohort, the mean age was 53 (SD = 17) years and 45% were female. During the median follow-up of 2.2 years (interquartile range, 0.6-3.8), 33 subjects (18%) developed an outcome event, the majority of which (85%) was heart transplant. The predictive accuracy of the reference model was 73% (sensitivity 76%, specificity 72%) while that of the machine learning model was 85% (e.g., sensitivity 88%, specificity 84% with elastic net regression). All 4 machine learning models significantly outperformed the reference model - e.g., area under the receiver-operating-characteristic curve 0.79 with the reference model vs. 0.93 with elastic net regression (p < 0.001). CONCLUSIONS: Compared with conventional risk stratification, the machine learning models demonstrated a superior ability to predict adverse cardiac events. These modern machine learning methods may enhance identification of high-risk HCM subpopulations.

Importance of surgical expertise in septal myectomy for obstructive hypertrophic cardiomyopathy.

OBJECTIVE: In 2011, a multidisciplinary hypertrophic cardiomyopathy (HCM) program with a dedicated myectomy surgeon was implemented at our institution. We hypothesized that a dedicated approach allows better identification and management of mitral regurgitation (MR) during septal myectomy (SM) for obstructive HCM with significant mitral regurgitation. METHODS: Between 2006 and 2018, 181 patients had SM at our institution. This study consists of 53 patients with preoperative moderate or greater MR associated with systolic anterior motion who underwent isolated SM with or without mitral intervention. Patients were divided into those who underwent SM by a dedicated myectomy surgeon (group D, n = 31) or by a non-dedicated surgeon (group ND, n = 22). Primary outcome of interest was rate of mitral valve replacement (MVR) at SM. Secondary outcomes include in-hospital mortality, need for permanent pacemaker, mitral valve reoperation, and residual MR and left ventricular outflow tract gradient on postoperative echocardiography. RESULTS: 12 patients (55%) had a concomitant MVR during septal myectomy in group ND compared to 2 patients (6%) in group D (p < 0.01). Among patients who did not undergo MVR, patients in group D less commonly had residual MR than patients in ND after SM (p < 0.01). Group D had 100% survival with NYHA class I in 94% patients at follow-up visit (p = 0.01). Reoperation for MVR was required in four patients in group ND vs. none in group D (p < 0.01). CONCLUSIONS: A dedicated surgeon is able to spare the mitral valve in patients undergoing SM. This study emphasizes the importance of surgical expertise in this cohort.

Heart failure in adult congenital heart disease: tetralogy of Fallot.

The number of rTOF patients who survive into adulthood is steadily rising, with currently more than 90% reaching the third decade of life. However, rTOF patients are not cured, but rather have a lifelong increased risk for cardiac and non-cardiac complications. Heart failure is recognized as a significant complication. Its occurrence is strongly associated with adverse outcome. Unfortunately, conventional concepts of heart failure may not be directly applicable in this patient group. This article presents a review of the current knowledge on HF in rTOF patients, including incidence and prevalence, the most common mechanisms of heart failure, i.e., valvular pathologies, shunt lesions, left atrial hypertension, primary left heart and right heart failure, arrhythmias, and coronary artery disease. In addition, we will review information regarding extracardiac complications, risk factors for the development of heart failure, clinical impact and prognosis, and assessment possibilities, particularly of the right ventricle, as well as management strategies. We explore potential future concepts that may stimulate further research into this field.

Predictors of Late Mortality in D-Transposition of the Great Arteries After Atrial Switch Repair: Systematic Review and Meta-Analysis.

Background Existing data on predictors of late mortality and prevention of sudden cardiac death after atrial switch repair surgery for D-transposition of the great arteries (D-TGA) are heterogeneous and limited by statistical power. Methods and Results We conducted a systematic review and meta-analysis of 29 observational studies, comprising 5035 patients, that reported mortality after atrial switch repair with a minimum follow-up of 10 years. We also examined 4 additional studies comprising 105 patients who reported rates of implantable cardioverter-defibrillator therapy in this population. Average survival dropped to 65% at 40 years after atrial switch repair, with sudden cardiac death accounting for 45% of all reported deaths. Mortality was significantly lower in cohorts that were more recent and operated on younger patients. Patient-level risk factors for late mortality were history of supraventricular tachycardia (odds ratio [OR] 3.8, 95% CI 1.4-10.7), Mustard procedure compared with Senning (OR 2.9, 95% CI 1.9-4.5) and complex D-TGA compared with simple D-TGA (OR 4.4, 95% CI 2.2-8.8). Significant risk factors for sudden cardiac death were history of supraventricular tachycardia (OR 4.7, 95% CI 2.2-9.8), Mustard procedure (OR 2.2, 95% CI 1.1-4.1), and complex D-TGA (OR 5.7, 95% CI 1.8-18.0). Out of a total 124 implantable cardioverter-defibrillator discharges over 330 patient-years in patients with implantable cardioverter-defibrillators for primary prevention, only 8% were appropriate. Conclusions Patient-level risk of both mortality and sudden cardiac death after atrial switch repair are significantly increased by history of supraventricular tachycardia, Mustard procedure, and complex D-TGA. This knowledge may help refine current selection practices for primary prevention implantable cardioverter-defibrillator implantation, given disproportionately high rates of inappropriate discharges.

Myocardial Contraction Fraction Predicts Cardiovascular Events in Patients With Hypertrophic Cardiomyopathy and Normal Ejection Fraction.

BACKGROUND: Myocardial contraction fraction (MCF), the ratio of left ventricular stroke volume to myocardial volume, is a novel parameter that can distinguish between pathologic and physiologic hypertrophy. However, its prognostic value in hypertrophic cardiomyopathy (HCM) has never been examined. The objective was to determine if MCF is associated with functional capacity and predicts adverse cardiovascular outcomes in patients with HCM and normal left ventricular ejection fraction (LVEF). METHODS AND RESULTS: We conducted a prospective cohort study of 137 patients with HCM and LVEF ≥55%. Patients were followed for 2.7 ± 2.5 years. We examined association of MCF with New York Heart Association (NYHA) functional class and a composite outcome of embolic stroke, heart transplantation, and cardiac death. We performed time-to-event analysis with the use of Cox proportional hazards modeling and stepwise elimination. The average age was 52 ± 18 years. The average MCF was 26 ± 11%. MCF was inversely correlated with NYHA functional class (P = .001). A total of 20 subjects experienced an outcome event with an event rate of 5.6% per patient-year. MCF independently predicted the outcome (adjusted hazard ratio 0.50 per 10% increase, 95% confidence interval 0.28-0.90, adjusted P = .02). CONCLUSIONS: In patients with HCM and normal LVEF, MCF is associated with functional capacity and independently predicts adverse cardiovascular outcomes.

Virtual septal myectomy for preoperative planning in hypertrophic cardiomyopathy.

OBJECTIVE: Although septal myectomy (SM) is the preferred treatment for medication-refractory obstructive hypertrophic cardiomyopathy, the procedure remains subjective. We have developed a virtual myectomy (VM) technique using 3-dimensional reconstruction of gated cardiac computed tomography (CT) to assist intraoperative objective assessment of the adequacy of the resection. METHODS: We retrospectively reviewed patients 15 patients who underwent a SM guided by preoperative VM at our program between March 2016 and July 2017. Gated cardiac CT was performed to allow delineation of the left ventricular (LV) myocardium at end-diastole to replicate the cardioplegic myocardial arrest (90%-95% RR interval). SM was performed to attain resection volume predicted by VM. Retrospective, blinded VM also was performed with fixed parameters to determine relationship between ideal (VM1) and conservative (VM2) VM and actual resection. RESULTS: Mean patient age was 52.1 ± 10.6 years, 27% were male, and 80% had New York Heart Association class 3 or 4. Preoperative mean peak LV outflow tract gradient was 79 mm Hg (range 47-82). In-hospital mortality was 0%. Mean postoperative LV outflow tract gradient was 13 mm Hg (11-19). Gated cardiac CT was performed with mean phase 94% (86%-98%). Mean total LV myocardial volume was 226 cm3 (146-365) and volume of the asymmetric portion of the LV was 19 cm3 (5.2-48.8). Actual surgical resection volume was 6.2 ± 1.7 cm3. Retrospective VM1 and VM2 performed postoperatively blinded to surgical results were 12.8 cm3 (4.8-29.23) and 6.7 cm3 (3.5-13.2), showing a modest correlation (R1 = 0.44, R2 = 0.56) with actual myectomy. CONCLUSIONS: Three-dimensional CT and VM can be a viable addition to preoperative assessment of patients with obstructive hypertrophic cardiomyopathy.

Multi-Modality Imaging in the Evaluation and Treatment of Tricuspid Regurgitation.

PURPOSE OF REVIEW: The goal of this review is to cover the epidemiology of tricuspid regurgitation (TR), anatomy of the tricuspid valve (TV), and the mechanisms and modern treatment of TR. The focus will be on the role of echocardiography, cardiac CT, and MRI to determine the mechanism, severity, and management strategies of TR. RECENT FINDINGS: The evaluation and management of TR is a rapidly growing field with significant advances in both imaging and interventions. Important advances have been made to understand TV anatomy and physiology in 3D echo, CT, and MRI. Additional understanding of the abnormal outcomes in both primary TR and secondary TR have been appreciated. Multiple transcatheter devices have reached the stage of early trials in high surgical risk cohorts with favorable initial findings. TR is a significant cardiovascular problem and vastly undertreated in the present era. There has been tremendous growth in knowledge of mechanisms of TR, its prognostic implications, timing of intervention, and development of novel treatment strategies. Multimodality imaging plays a key role in evaluation and treatment of this condition.

Long-term Management of the Arterial Switch Patient.

PURPOSE OF REVIEW: This review paper describes the management of patients with dextro-transposition of the great arteries (D-TGA) with a focus on the complications seen and the appropriate care required to identify and prevent adverse events. RECENT FINDINGS: D-TGA is a form of cyanotic congenital heart disease (CHD) representing ~ 3% of all CHD and almost 20% of all cyanotic CHD. Since the late 1980s, standard of care is to repair these patients with an arterial switch operation (ASO) as opposed to a Mustard/Senning operation. The long-term survival and complication rates are superior in the ASO. Long-term follow-up is recommended for all D-TGA patients and includes management with adult congenital heart disease specialists and the use of echocardiography and advanced imaging with CT or MRI. The most common complications seen are pulmonary stenosis, coronary artery stenosis, and neo-aortic regurgitation. Careful evaluation of new symptoms or declining function is essential in preventing and treating these long-term sequelae.

Role of computed tomography angiography for HeartMate II left ventricular assist device thrombosis.

INTRODUCTION: Device thrombosis is one of the most devastating complications of HeartMate II left ventricular assist devices. The purpose of this study is to assess the anatomical properties that the inflow and outflow computed tomography angiography provides in assessing for left ventricular assist device thrombosis, as well as their impact on clinical management and postoperative outcomes. METHODS: Between April 2010 and December 2016, 22 patients who received a HeartMate II left ventricular assist device implantation were readmitted for suspected device thrombosis and underwent a computed tomography angiography for workup. Left ventricular assist device-associated anatomy was assessed, including outflow abnormality on computed tomography angiography (contrast filling defect), inflow abnormalities on computed tomography angiography (space at inflow, M-I angle), and inflow abnormalities on chest X-ray (inflow angulation, pump pocket depth). RESULTS: Computed tomography angiography revealed an outflow filling defect in three patients (14%) resulting in change in surgical approach from subcostal pump exchange to resternotomy pump and outflow graft exchange. Inflow graft malpositioning was identified in four patients, with the inflow abutting the left ventricular wall and obstructing the cannula opening. On computed tomography angiography assessment, mean space at inflow was 5.3 ± 1.6 mL and M-I angle was 35.6° ± 6.6°. Chest X-ray evaluation revealed mean inflow angle and pump pocket depth of 75.7° ± 13.4° and 110.2 ± 26.6 mm, respectively. CONCLUSION: Computed tomography angiography provides a noninvasive assessment of the outflow graft and inflow cannulas in left ventricular assist device patients. Findings on computed tomography angiography reveal possible mechanical etiologies of thrombosis and may be useful for determining the surgical management of device thrombosis patients.

Septal myectomy for hypertrophic cardiomyopathy: important surgical knowledge and technical tips in the era of increasing alcohol septal ablation.

Hypertrophic cardiomyopathy (HCM) is the most commonly inherited cardiac disease-recent studies suggest a prevalence as high as 1 in 200. For symptomatic patients with obstructive HCM who are refractory to medical therapy, septal reduction is indicated. Septal myectomy (SM) is considered the gold standard septal reduction technique. However, due to a shortage of surgeons who are experienced in this technique, alcohol septal ablation (ASA) has overtaken SM as the most commonly performed procedure for obstructive HCM. In this review, we summarize the existing literature comparing SM with ASA and describe recent innovations in operative technique, including a detailed description of the approach used at our institution.

Scimitar Syndrome in Children and Adults: Natural History, Outcomes, and Risk Analysis.

BACKGROUND: Scimitar syndrome involves congenital anomalous pulmonary venous return to the inferior vena cava. Optimal management remains controversial. We describe the natural history of disease, nonsurgical and surgical outcomes, and risk factors for poor outcomes at our institution. METHODS: Patients with anomalous pulmonary venous return to the inferior vena cava documented on echocardiography at our institution between January 1994 and January 2015 were reviewed retrospectively. The study protocol IRB-AAAO1805 was approved. RESULTS: Forty-seven patients were identified, including 20 infants with significant associated congenital heart defects (42.6%, including 7 with single ventricle physiology), and 10 infants (21.3%) and 16 noninfants (34.0%) with isolated scimitar syndrome. Median follow-up was 3.55 years. Noninfants exhibited lower incidences of right pulmonary artery hypoplasia (p < 0.001), aortopulmonary collaterals (p = 0.004), and scimitar vein obstruction at the caval confluence (p = 0.032). Eighteen patients (38.3%) underwent surgical repair for scimitar syndrome. Overall mortality after baffle repair or scimitar vein reimplantation was 37.5% (3 of 8) for infants and 0% (0 of 6) for noninfants (p = 0.209). Overall mortality for medically managed infants was 46.7% (7 of 15) compared with 0% (0 of 8) for noninfants (p = 0.052). Multivariable analyses identified infantile onset as an independent risk factor for stenosis or obstruction after repair (hazard ratio 9.34, p = 0.048), and single ventricle physiology as an independent risk factor for mortality among unrepaired patients (hazard ratio 29.8, p = 0.004). CONCLUSIONS: The severity of scimitar syndrome depends on presenting age and associated congenital heart disease. Nonsurgical and surgical outcomes are suboptimal for infantile disease, which is a risk factor for stenosis after repair. Single ventricle physiology is associated with poor prognosis.

Diagnosis and Management of Noncardiac Complications in Adults With Congenital Heart Disease: A Scientific Statement From the American Heart Association.

Life expectancy and quality of life for those born with congenital heart disease (CHD) have greatly improved over the past 3 decades. While representing a great advance for these patients, who have been able to move from childhood to successful adult lives in increasing numbers, this development has resulted in an epidemiological shift and a generation of patients who are at risk of developing chronic multisystem disease in adulthood. Noncardiac complications significantly contribute to the morbidity and mortality of adults with CHD. Reduced survival has been documented in patients with CHD with renal dysfunction, restrictive lung disease, anemia, and cirrhosis. Furthermore, as this population ages, atherosclerotic cardiovascular disease and its risk factors are becoming increasingly prevalent. Disorders of psychosocial and cognitive development are key factors affecting the quality of life of these individuals. It is incumbent on physicians who care for patients with CHD to be mindful of the effects that disease of organs other than the heart may have on the well-being of adults with CHD. Further research is needed to understand how these noncardiac complications may affect the long-term outcome in these patients and what modifiable factors can be targeted for preventive intervention.

Outcomes and Prognostic Factors for Adult Patients With Congenital Heart Disease Undergoing Primary or Reoperative Systemic Atrioventricular Valve Surgery.

BACKGROUND: Adults with congenital heart disease (ACHD) undergoing systemic atrioventricular valve (SAVV) surgery are a complex, understudied population. We assessed midterm outcomes and prognostic factors in ACHD undergoing SAVV surgery. METHODS: We performed retrospective evaluation of ACHD undergoing SAVV surgery from January 2005 to February 2016: 14 (33%) patients with congenital mitral valve stenosis/regurgitation, 15 (35%) with atrioventricular septal defect (AVSD), and 14 (33%) with congenitally corrected transposition of the great arteries (ccTGA) with systemic tricuspid valve regurgitation. Adverse events were defined as mortality, reoperation on SAVV, and late more-than-moderate (> moderate) SAVV regurgitation. Statistical analysis was performed using Fisher's exact test and one-way analysis of variance as well as univariate and multivariate risk factor analysis. RESULTS: Fifteen (35%) patients had preoperative systemic ventricular dysfunction, including 13 patients with ccTGA (93%, P < .001). Twenty-three (54%) patients underwent valve repair, 20 (47%) patients underwent replacement, and 20 (47%) patients underwent an associated procedure. Replacement was higher in patients with ccTGA (86%) than the other groups ( P < 0.01). Thirty-seven patients (91% of survivors) were free of significant SAVV regurgitation at last follow-up, with patients with AVSD having greater regurgitation grades compared to the other groups ( P < 0.01). In-hospital mortality, late mortality, late > moderate SAVV regurgitation, and SAVV reoperation rates were 5% (n = 2), 2% (n = 1), 9% (n = 3), and 7% (n = 3), respectively. On multivariate analysis, predischarge SAVV regurgitation grade was the only significant predictor of adverse events (odds ratio = 8.2, 95% confidence interval: 1.1-63.8, P = .045). CONCLUSION: Overall outcomes in this challenging population are good. The single factor associated with adverse events was predischarge SAVV regurgitation grade.

Serial cardiac MRIs in adult Fontan patients detect progressive hepatic enlargement and congestion.

BACKGROUND: The progression of hepatic disease in adult Fontan patients is not well understood. They reviewed the experience with serial cardiac MRIs (CMR) in adult Fontan patients to determine if hepatic anatomic markers of prolonged Fontan exposure were present and if clinical predictors of progressive hepatic congestion could be identified. METHODS AND RESULTS: A retrospective cohort study of all adult Fontan patients who had undergone at least two CMRs was performed. Hepatic dimensions, inferior vena cava (IVC) size, right hepatic vein (RHV) size and spleen diameter were determined from images acquired at the time of clinically guided CMR. Two radiologists with expertise in hepatic imaging graded congestion and liver size independently using post-gadolinium contrast sequences. Twenty-seven patients met inclusion criteria. Over a mean time of 5.1 years between CMRs, there was a significant increase in mean lateral-medial hepatic dimension (P = .005), mean RHV diameter (P = .004), and mean splenic diameter (P = .001). Serial post-gadolinium imaging was available in 25/27 (93%) patients of which 15/27 (55%) showed evidence of progressive hepatic congestion across serial studies. Progressive hepatic congestion was associated with single ventricle ejection fraction (SVEF) less than 50% (P = .008), and larger indexed end-diastolic (EDVI) and end-systolic volume (ESVI). RHV diameter was the only anatomic variable significantly correlated with time from Fontan completion (P = .004). CONCLUSIONS: Serial CMRs detected progressive liver and hepatic vein enlargement in our cohort of adult Fontan patients over a mean time of 5.2 years. Progressive hepatic congestion occurs in a significant number of adult Fontan patients and may be associated with ventricular enlargement and decreased ventricular function by CMR.