Prediction of Sudden Cardiac Arrest After Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy: ASA-SCARRE Risk Score

Trans-Atlantic Differences in Approach to Sudden Death Prevention in Patients With Hypertrophic Cardiomyopathy

The American approach to predicting sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy diverges from the European method in that it relies on major risk factors independently justifying the implantation of an implantable cardioverter-defibrillator for primary prevention, whereas the European approach uses a mathematical equation to estimate a 5-year risk percentage. The aim of this review is to outline the differences between the American and European guidelines and to show how they have arisen. Furthermore, it will provide insight into the future of SCD risk prediction in patients with hypertrophic cardiomyopathy. The American SCD risk prediction method has high sensitivity but limited specificity, whereas the European method has the opposite. These differences in sensitivity and specificity likely contribute to the fact that primary prevention implantable cardioverter-defibrillator utilization is twofold higher in the United States. It is highly likely that new insights and new imaging modalities will enhance prediction models in the near future. Genotyping could potentially assume a significant role. Left ventricular global longitudinal strain was recently shown to be an independent predictor of SCD. Furthermore, after late gadolinium enhancement, additional cardiac magnetic resonance techniques such as T1 mapping and diffusion tensor imaging are showing encouraging outcomes in predicting SCD. Ultimately, it is conceivable that integrating diverse morphological and genetic characteristics through deep learning will yield novel insights and enhance SCD prediction methods.

Looking Back at 30 Years of Alcohol Septal Ablation and Looking Forward to the Future

In the 30 years since Dr Sigwart's first pioneering procedures, alcohol septal ablation (ASA) has become the standard catheterisation procedure to reduce or eliminate obstruction in the left ventricular outflow tract. This procedure reduces the pressure gradient by 70%-80%, and only 10%-20% of patients have a residual gradient > 30 mm Hg after ASA. The mortality rate of the procedure is < 1%, and ∼ 10% of patients require permanent pacemaker implantation for higher degrees of atrioventricular block. Given the potential risks, ASA should be performed only in centres with extensive experience in the treatment of hypertrophic cardiomyopathy and with comprehensive therapeutic options, including myectomy. In the future, ASA is likely to be increasingly complemented by catheter-based mitral valve repair, which will increase its efficacy.

Interventions in Hypertrophic Obstructive Cardiomyopathy

Obstructive hypertrophic cardiomyopathy is the most common genetically transmitted cardiomyopathy that is associated with significant morbidity and mortality. Despite contemporary treatments and interventions, the management of patients with obstructive hypertrophic cardiomyopathy remains poorly defined compared with other branches of cardiology. In this review, we discuss established and novel therapeutic interventions in patients with obstructive hypertrophic cardiomyopathy with a focus on percutaneous and surgical strategies including surgical myectomy, mitral valve repair or replacement, percutaneous alcohol septal ablation, pacemaker and cardioverter-defibrillator implantation, septal embolization, radiofrequency endocardial catheter ablation, and percutaneous intramyocardial septal radiofrequency ablation.

Trends of hypertrophic cardiomyopathy-related mortality in United States young adults: a nationwide 20-year analysis

AIMS

Data regarding hypertrophic cardiomyopathy (HCM)-related mortality in United States young adults, defined as those aged between 25 and 44 years, are lacking. We sought to assess the trends in HCM-related mortality among US young adults between 1999 and 2019 and determine differences by sex, race, ethnicity, urbanization and census region.

METHODS

Mortality data were retrieved by the Centers for Disease Control and Prevention (CDC) Wide-Ranging Online Data for Epidemiologic Research (WONDER) dataset from January 1999 to December 2019. Age-adjusted mortality rates (AAMRs) were assessed using the Joinpoint regression modeling and expressed as estimated average annual percentage change (AAPC) with relative 95% confidence intervals (95% CIs).

RESULTS

Over 20-year period, the AAMR from HCM in US young adults linearly decreased, with no differences between sexes [AAPC: -5.3% (95% CI -6.1 to -4.6), P  < 0.001]. The AAMR decrease was more pronounced in Black patients [AAPC: -6.4% (95% CI -7.6 to -5.1), P  < 0.001], Latinx/Hispanic patients [AAPC: -4.8% (95% CI -7.2 to -2.36), P  < 0.001] and residents of urban areas [AAPC: -5.4% (95% CI -6.2 to -4.6), P  < 0.001]. The higher percentages of HCM-related deaths occurred in the South of the country and at the patient's home.

CONCLUSION

HCM-related mortality in US young adults has decreased over the last two decades in the United States. Subgroup analyses by race, ethnicity, urbanization and census region showed ethnoracial and regional disparities that will require further investigation.

Long-Term Clinical Outcome After Alcohol Septal Ablation and Its Periprocedural Predictive Factors in Japan - A Retrospective Observational Study

BACKGROUND

Evidence is limited regarding long-term clinical outcomes after alcohol septal ablation (ASA) for patients with hypertrophic obstructive cardiomyopathy and its periprocedural predictive factors in Japan.

METHODS AND RESULTS

This retrospective observational study included 44 patients who underwent ASA between 1998 and 2022 in a single center. We evaluated the periprocedural change in variables and long-term clinical outcomes after the procedure. The primary outcome was a composite of cardiovascular death or hospitalization for heart failure. The secondary outcome was all-cause death. Using multivariable Poisson regression with robust error variance, we predicted underlying periprocedural factors related to primary outcome development. ASA decreased the median pressure gradient at the left ventricular outflow tract from 88 to 33 mmHg and reduced moderate or severe mitral regurgitation (MR), present in 53% of patients before ASA, to 16%. Over a median 6-year follow-up, the cumulative incidence of the primary outcome at 5 and 10 years was 16.5% and 25.6%, respectively. After multivariable analysis, moderate or severe MR after ASA was significantly associated with the primary outcome (relative risk 8.78; 95% confidence interval 1.34-57.3; P=0.024). All-cause mortality after ASA was 15.1% and 28.9% at 5 and 10 years, respectively.

CONCLUSIONS

This study presents long-term clinical outcomes after ASA in Japan. Moderate or severe MR after ASA was significantly associated with the composite of cardiovascular death or hospitalization for heart failure.

Outcomes of Alcohol Septal Ablation in Patients With Severe Left Ventricular Outflow Tract Obstruction: A Propensity Score Matching Analysis

BACKGROUND

The current ACC/AHA guidelines on hypertrophic cardiomyopathy (HCM) caution that alcohol septal ablation (ASA) might be less effective in patients with left ventricular outflow tract obstruction (LVOTO) ≥ 100 mm Hg.

METHODS

We used a multinational registry to evaluate the outcome of ASA patients according to baseline LVOTO.

RESULTS

A total of 1346 ASA patients were enrolled and followed for 5.8 ± 4.7 years (7764 patient-years). The patients with baseline LVOTO ≥ 100 mm Hg were significantly older (61 ± 14 years vs 57 ± 13 years; P < 0.01), more often women (60% vs 45%; P < 0.01), and had a more pronounced HCM phenotype than those with baseline LVOTO < 100 mm Hg. There were no significant differences in the occurrences of 30-day major cardiovascular adverse events in the 2 groups. After propensity score matching (2 groups, 257 pairs of patients), the long-term survival was similar in both groups (P = 0.10), the relative reduction of LVOTO was higher in the group with baseline LVOTO ≥ 100 mm Hg (82 ± 21% vs 73 ± 26%; P < 0.01), but the residual resting LVOTO remained higher in this group (23 ± 29 mm Hg vs 13 ± 13 mm Hg; P < 0.01). Dyspnoea (NYHA functional class) at the most recent clinical check-up was similar in the 2 groups (1.7 ± 0.7 vs 1.7 ± 0.7; P = 0.85), and patients with baseline LVOTO ≥ 100 mm Hg underwent more reinterventions (P = 0.02).

CONCLUSIONS

After propensity matching, ASA patients with baseline LVOTO ≥ 100 mm Hg had similar survival and dyspnoea as patients with baseline LVOTO < 100 mm Hg, but their residual LVOTO and risk of repeated procedures were higher.

Invasive therapies for symptomatic obstructive hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic condition with multiple different genetic and clinical phenotypes. As awareness for HCM increases, it is important to also be familiar with potential treatment options for the disease. Treatment of HCM can be divided into two different categories, medical and interventional. Typically for obstructive forms of the disease, in which increased septal hypertrophy, abnormally placed papillary muscles, abnormalities in mitral valve or subvalvular apparatus, lead to dynamic left ventricular outflow tract (LVOT) obstruction, treatment is targeted at decreasing obstructive gradients and therefore symptoms. Medications like beta blockers, calcium channel blockers, disopyramide can often accomplish this. However, in patients with severe obstruction or symptoms refractory to medical therapy, either surgical correction of the LVOT obstruction or percutaneous via alcohol septal ablation, are treatment options. In this review, we will focus on the invasive treatment of hypertrophic obstructive cardiomyopathy.