Obstruction after alcohol septal ablation is associated with cardiovascular mortality events

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.

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.

A Narrative Review of Emerging Therapies for Hypertrophic Obstructive Cardiomyopathy

Hypertrophic obstructive cardiomyopathy is a hereditary condition that affects myocardial contraction. In case of failure of pharmacological treatment, alternative approaches might be used that include surgical myectomy, percutaneous transluminal septal myocardial ablation, and radiofrequency ablation. In respect of long-term advantages, surgical septal myectomy remains the therapy of choice for symptomatic hypertrophic obstructive cardiomyopathy. Alcohol septal ablation has been considered an alternative to surgical myectomy, which confers the benefits of a shorter hospital stay, less discomfort, and fewer complications. However, only expert operators should perform it on carefully chosen patients. Further, radiofrequency septal ablation reduces the left ventricular outflow tract gradient and improves the NYHA functional class of patients with hypertrophic obstructive cardiomyopathy, despite complications like cardiac tamponade and atrioventricular block. Further research with a larger sample size is required to compare the radiofrequency approach with established invasive treatment methods for hypertrophic obstructive cardiomyopathy. Septal myectomy has low morbidity and mortality rates, making it the preferred procedure; however, the efficacy and morbidity remain debatable. Advances in invasive techniques, including percutaneous septal radiofrequency ablation and transcatheter myotomy, have provided alternative approaches for reducing left ventricular outflow tract (LVOT) obstruction in patients who are not candidates for traditional surgical septal myectomy. Candidates for alcohol and radiofrequency septal ablation include patients with symptomatic hypertrophic obstructive cardiomyopathy, older adults, and those with multiple comorbidities.

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

This study aimed to derive a new score, the Alcohol Septal Ablation-Sudden Cardiac ARREst (ASA-SCARRE) risk score, that can be easily used to evaluate the risk of sudden cardiac arrest events (sudden cardiac death, resuscitation, or appropriate implantable cardioverter-defibrillator discharge) after alcohol septal ablation (ASA) in patients with hypertrophic obstructive cardiomyopathy. We analyzed 1,834 patients from the Euro-ASA registry (49% men, mean age 57 ± 14 years) who were followed up for 5.0 ± 4.3 years (9,202 patient-years) after ASA. A total of 65 patients (3.5%) experienced sudden cardiac arrest events, translating to 0.72 events per 100 patient-years. The independent predictors of sudden cardiac arrest events were septum thickness before ASA (hazard ratio 1.09 per 1 mm, 95% confidence interval 1.04 to 1.14, p <0.001) and left ventricular outflow tract (LVOT) gradient at the last clinical checkup (hazard ratio 1.01 per 1 mm Hg, 95% confidence interval 1.01 to 1.02, p = 0.002). The following ASA-SCARRE risk scores were derived and independently predicted long-term risk of sudden cardiac arrest events: "0" for both LVOT gradient <30 mmHg and baseline septum thickness <20 mm; "1" for LVOT gradient ≥30 mm Hg or baseline septum thickness ≥20 mm; and "2" for both LVOT gradient ≥30 mm Hg and baseline septum thickness ≥20 mm. The C statistic of the ASA-SCARRE risk score was 0.684 (SE 0.030). In conclusion, the ASA-SCARRE risk score may be a useful and easily available clinical tool to predict risk of sudden cardiac arrest events after ASA in patients with hypertrophic obstructive cardiomyopathy.

Preoperative myocardial fibrosis is associated with worse survival after alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy: A delayed enhanced cardiac magnetic resonance study

Background

Prior studies have shown that myocardial fibrosis can be detected by late gadolinium enhancement (LGE) of cardiac magnetic resonance (CMR) and might be associated with higher mortality risk in hypertrophic cardiomyopathy (HCM). The objective of this study was to examine the prognostic utility of CMR in patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing alcohol septal ablation (ASA).

Materials and methods

We conducted a retrospective study which consisted of 183 consecutive patients with symptomatic drug-refractory HOCM who underwent CMR for assessment of myocardial fibrosis before ASA. The cardiovascular disease related survival was evaluated according to LGE-CMR status.

Results

The cohort comprised 74 (40.4%) women with a mean age of 51 ± 8 years. Preoperative myocardial fibrosis was detected in 148 (80.9%) patients. After a median of 6 years (range 2–11 years) follow-up, adverse clinical events occurred in 14 (7.7%) patients. Multivariate-adjusted Cox regression analyses revealed that age [hazard ratio (HR) 1.142 (1.059–1.230), p = 0.001] and LGE [HR 1.170 (1.074–1.275), p &lt; 0.001] were independent predictors of cardiovascular mortality during follow-up.

Conclusion

Preoperative myocardial fibrosis measured by LGE-CMR was an independent predictor of increased adverse clinical outcomes in patients with HOCM undergoing ASA and could be used for the pre-operative evaluation of risk stratification and long-term prognosis after ASA in these patients.

Real-world clinical outcomes of percutaneous transluminal septal myocardial ablation for patients with drug-refractory hypertrophic obstructive cardiomyopathy: results from a retrospective multicenter registry of non-high-volume centers

Percutaneous transluminal septal myocardial ablation (PTSMA) is a well-established interventional therapy for drug-refractory hypertrophic obstructive cardiomyopathy (HOCM) as an alternative to surgical myectomy. Although guidelines recommend that PTSMA should be performed in institutions with extensive experience, it is not centralized to such high-volume centers in real-world clinical practice. Thus, this study aimed to assess the feasibility of PTSMA in non-high-volume centers. We retrospectively examined patients with HOCM who underwent PTSMA between August 2012 and May 2020 at four institutions that experienced fewer than 20 cases of PTSMA procedures. The primary clinical endpoint was a composite of safety (all-cause death, electrical defibrillation for ventricular tachycardia or fibrillation, cardiac tamponade, permanent pacemaker implantation, and repeated interventions) and efficacy endpoints (repeated interventions [PTSMA or surgical myectomy]). Fifty-eight consecutive patients were enrolled. During the 30-day follow-up, no major clinical adverse events were noted except three patients (5.2%) requiring permanent pacemaker implantation for complete atrioventricular block. The percentage of patients with New York Heart Association functional class 1 or 2 significantly increased from 8.6 to 100% (p < 0.001). In the Cox proportional hazard model, left ventricular outflow tract pressure gradient at rest ≥ 30 mmHg (hazard ratio [HR] 6.56; 95% confidence interval [CI] 1.44-29.90; p = 0.015) and mitral regurgitation grade ≥ 3 (HR 10.75; 95% CI 1.81-63.79; p = 0.009) at the 30-day follow-up were associated with a composite of major clinical adverse events. The current study demonstrated that 58 patients who underwent PTSMA in non-high-volume centers had favorable 30-day clinical outcomes, with a primary composite endpoint rate of 5.2%. A prospective study with a larger sample size and longer follow-up is warranted to verify the safety and efficacy of PTSMA in non-high-volume centers.

The first 200 septal myectomies: Ensuring gold standard outcomes

OBJECTIVES

Septal myectomy remains the gold standard treatment for symptomatic left ventricular outflow tract obstruction refractory to medical treatment. It is recommended that this operation be performed in dedicated hypertrophic obstructive cardiomyopathy centres by experienced surgeons. The septal myectomy option remains unavailable to many patients based solely on geography, including those who would clearly benefit more substantially from surgery than other therapeutic options. Here, we share our experience in starting new hypertrophic cardiomyopathy programmes.

METHODS

We retrospectively reviewed initial septal myectomy experiences at two hypertrophic cardiomyopathy programmes starting in 2014.

RESULTS

Two-hundred septal myectomies were performed. Mean age was 58.8 years and 51% were females. Advanced heart failure symptoms were present in 95.5% of patients and 23.5% had experienced syncope. Mean maximal intraventricular gradient was 89 mmHg and 48.5% underwent concomitant procedures at the time of septal myectomy. There was no perioperative (in-hospital or 30 days) mortality. Ninety-two per cent had provoked left ventricular gradients of ≤ 15 mmHg and 97% had none/mild mitral regurgitation at post-operative assessment. In our contemporary cohort, there were 2 (1%) intraoperative ventricular septal defects and 5% required a permanent pacemaker.

CONCLUSIONS

Our early septal myectomy experience targeted a complex population, frequently in need of concomitant procedures. Abolition of left ventricular obstruction and resolution of systolic anterior motion mediated mitral regurgitation can be expected. The safety and efficacy of septal myectomy carried at hypertrophic cardiomyopathy centres by properly trained surgeons achieved the desired outcomes established by recent hypertrophic cardiomyopathy guidelines.

Outcomes of Septal Myectomy beyond 65 Years, with and without Concomitant Procedures

Introduction and objectives: Septal myectomy remains the first septal reduction therapy for hypertrophic obstructive cardiomyopathy in young patients and those requiring concomitant procedures. Its role in advanced ages is questioned due to perceived increased risk. We assess the outcomes of surgical relief of obstruction in patients beyond 65 years old. Methods: A single-center retrospective review of patients ≥ 65 years old undergoing septal myectomy through median sternotomy between April 2015 and February 2020. Results: We identified 52 patients. Mean age was 71.8 ± 4.9 years; 36 (69.2%) were females. All were symptomatic. Mean highest LVOT gradient was 90 ± 39 mmHg. All patients had systolic anterior motion (SAM) of the mitral valve and 36 (69.2%) ≥ moderate mitral regurgitation. Additional LVOT interventions beyond myectomy were performed in 34 (65.4%). At least one other cardiac concomitant procedure was performed 44 (84.6%). No perioperative mortality in elective surgery occurred. One patient (1.9%) developed atrio-ventricular block. Postoperative mean gradient was 4.3 ± 1.9 mmHg, with 46 (88.4%) achieving complete resolution of obstruction. Mitral regurgitation was reduced to grade ≤ I in 46 (88.5%). Mean follow-up time was 2.3 ± 1.2 years and 82% of patients were in NYHA I. Survival at 2 years was 98%. Conclusion: Septal myectomy in the elderly is a safe and effective operation despite the need for concomitant procedures. LVOT interventions beyond septal myectomy to relieve obstruction are common in this advanced cohort of hypertrophic cardiomyopathy patients. This operation carried at experienced centers seems an unmatched therapeutic option.

Outcome of alcohol septal ablation in mildly symptomatic patients with hypertrophic obstructive cardiomyopathy: A comparison with medical therapy

Objective

The aim of this study was primarily to determine efficacy after alcohol septal ablation (ASA) in mildly symptomatic patients (NYHA class II) with hypertrophic obstructive cardiomyopathy (HOCM), as compared to medical therapy.

Methods

This retrospective study included 163 mildly symptomatic patients with HOCM evaluated in Beijing Anzhen Hospital between March 2001 and August 2019, consisting of the medical group (n = 105) and the ASA group (n = 58). All‐cause mortality and HCM‐related death were mainly observed.

Results

Follow‐up was completed in 161 patients and the median follow‐up was 6.0 years. Compared to medically treated patients, patients post‐ASA had comparable survival free of all‐cause mortality (98.3% and 95.1% vs. 93.0% and 83.1% at 5 and 10 years, respectively; p = 0.374). Survival free of HCM‐related death was also similar between ASA and medical groups (98.3% and 95.1% vs. 94.3% and 86.2% at 5 and 10 years, respectively; p = 0.608). However, compared to medical therapy, ASA had advantages on the improvement of NYHA class (1.4 ± 0.6 vs. 2.1 ± 0.5, p = .000) and lower occurrence of new‐onset atrial fibrillation (AF) (7.8% vs. 20.4%, p = .048). Multivariate analysis demonstrated that resting LVOT gradient at the last clinical check‐up was an independent predictor of all‐cause mortality (HR = 1.021, 95%CI 1.002–1.040, p = .027).

Conclusion

This registry suggests that mildly symptomatic patients with HOCM treated with ASA have comparable survival to that of medically treated patients, with the improvement of NYHA class and lower occurrence of new‐onset AF. All‐cause mortality is independently associated with resting LVOT gradient at the last clinical check‐up.

Targeting Alcohol Septal Ablation in Patients with Obstructive Hypertrophic Cardiomyopathy Candidates for Surgical Myectomy: Added Value of Three-Dimensional Intracoronary Myocardial Contrast Echocardiography

Background: Myocardial contrast two-dimensional echocardiography (MC-2DE) is widely used to address alcohol septal ablation (ASA) in obstructive hypertrophic cardiomyopathy (HCM). Owing to its limited cut-planes, MC-2DE may inaccurately identify the contrast misplacement associated with an unsuccessful or complicated ASA outcome. Objective: The aim of this study was to assess the added value of myocardial contrast three-dimensional echocardiography (MC-3DE) compared with MC-2DE to identify the appropriate matching between the target septal zone (TSZ) and coronary artery branch for safe and long-term effective ASA in HCM patients. Methods: A consecutive series of 52 symptomatic obstructive HCM patients referred for isolated surgical myectomy (SM) was analyzed with MC-2DE and MC-3DE following injection of echocontrast into one or more septal branches. MC-2DE and MC-3DE patterns were categorized according to complete (Type 1) or incomplete (Type 2) TSZ covering, high-risk (Type 3) exceeding TSZ, or life-threatening outside TSZ distribution (Type 4). Results: MC-2DE per patient analysis showed a Type 1 pattern in 32 patients and Types 2–4 in the remaining 20 patients; subsequent MC-3DE analysis provided a re-phenotyping of MC-2DE findings in 22 of the 52 patients (42%), showing a high-risk Type 2 pattern in 17 of the 32 patients with Type 1, and a new life-threatening Type 4 in three patients with Type 2, respectively. All patients with MC-3DE Type 1 pattern underwent safe and effective ASA with a long-term uneventful follow-up, while the remaining patients underwent SM. Conclusions: Refining high risk or life-threatening contrast misplacement, MC-3DE is more accurate than conventional MC-2DE to target safe and long-term effective septal reduction with ASA in obstructive HCM patients referred for isolated SM.

Relationship Between Procedural Right Bundle Branch Block and 1-Year Outcome After Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy - A Retrospective Study

BACKGROUND

Alcohol septal ablation (ASA) is a treatment option in patients with drug-refractory symptomatic hypertrophic obstructive cardiomyopathy (HOCM). In many patients, right bundle branch block (RBBB) develops during ASA because septal branches supply the right bundle branch. However, the clinical significance of procedural RBBB is uncertain.Methods and Results:We retrospectively reviewed 184 consecutive patients with HOCM who underwent ASA. We excluded 40 patients with pre-existing RBBB (n=10), prior pacemaker implantation (n=15), mid-ventricular obstruction type (n=10), and those lost to follow-up (n=5), leaving 144 patients for analysis. Patients were divided into 2 groups according to the development (n=95) or not (n=49) of procedural RBBB. ASA conferred significant decreases in the left ventricular pressure gradient (LVPG) in both the RBBB and no-RBBB group (from 74±48 to 27±27 mmHg [P<0.001] and from 75±45 to 31±33 mmHg [P<0.001], respectively). None of the RBBB patients developed further conduction system disturbances. The percentage reduction in LVPG at 1 year after the procedure was significantly greater in the RBBB than no-RBBB group (66±24% vs. 49±45%; P=0.035). Procedural RBBB was not associated with pacemaker implantation after ASA, but was associated with reduction in repeat ASA (odds ratio 0.34; 95% confidence interval 0.13-0.92; P=0.045).

CONCLUSIONS

Although RBBB frequently occurs during the ASA procedure, it does not adversely affect clinical outcomes.

Alcohol dose in septal ablation for hypertrophic obstructive cardiomyopathy

BACKGROUND

The aim of this study was to evaluate short- and long-term outcomes related to dose of alcohol administered during alcohol septal ablation (ASA) in patients with hypertrophic obstructive cardiomyopathy (HOCM). Current guidelines recommend using 1-3 mL of alcohol administered in the target septal perforator artery, but this recommendation is based more on practical experience of interventionalists rather than on systematic evidence.

METHODS

We included 1448 patients and used propensity score to match patients who received a low-dose (1.0-1.9 mL) versus a high-dose (2.0-3.8 mL) of alcohol during ASA.

RESULTS

The matched cohort analysis comprised 770 patients (n = 385 in both groups). There was a similar occurrence of 30-day post-procedural adverse events (13% vs. 12%; p = 0.59), and similar all-cause mortality rates (0.8% vs. 0.5%; p = 1) in the low-dose group and the high-dose group, respectively. In the long-term follow-up (5.4 ± 4.5 years), a total of 110 (14%) patients died representing 2.58 deaths and 2.64 deaths per 100 patient-years in the low dose and the high dose group (logrank, p = 0.92), respectively. There were no significant differences in the long-term dyspnea and left ventricular outflow gradient between the two groups. Patients treated with a low-dose of alcohol underwent more subsequent septal reduction procedures (logrank, p = 0.04).

CONCLUSIONS

Matched HOCM patients undergoing ASA with a low-dose (1.0-1.9 mL) or a high-dose (2.0-3.8 mL) of alcohol had similar short- and long-term outcomes. A higher rate of repeated septal reduction procedures was observed in the group treated with a low-dose of alcohol.

Short- and long-term outcomes of alcohol septal ablation for hypertrophic obstructive cardiomyopathy in patients with mild left ventricular hypertrophy: a propensity score matching analysis

AIMS

Based on European guidelines, alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM) is indicated only in patients with interventricular septum (IVS) thickness >16 mm. The aim of this study was to evaluate the short- and long-term outcomes in ASA patients with mild hypertrophy (IVS ≤ 16 mm).

METHODS AND RESULTS

We retrospectively evaluated 1505 consecutive ASA patients and used propensity score to match 172 pairs (344 patients) in groups IVS ≤ 16 mm or IVS > 16 mm. There was no occurrence of post-ASA ventriculoseptal defect in the whole cohort (n = 1505). Matched patients had 30-day mortality rate 0% in IVS ≤ 16 mm group and 0.6% in IVS > 16 mm group (P = 1). Patients in IVS ≤ 16 mm group had more ASA-attributable early complications (16% vs. 9%; P = 0.049), which was driven by higher need for pacemaker implantation (13% vs. 8%; P = 0.22). The mean follow-up was 5.4 ± 4.3 years and the annual all-cause mortality rate was 1.8 and 3.2 deaths per 100-patient-years in IVS ≤ 16 group and IVS > 16 group, respectively (log-rank test P = 0.04). There were no differences in symptom relief and left ventricular (LV) gradient reduction. Patients with IVS ≤ 16 mm had less repeated septal reduction procedures (log-rank test P = 0.03).

CONCLUSION

Selected patients with HOCM and mild hypertrophy (IVS ≤ 16 mm) had more early post-ASA complications driven by need for pacemaker implantation, but their long-term survival is better than in patients with IVS >16 mm. While relief of symptoms and LV obstruction reduction is similar in both groups, a need for repeat septal reduction is higher in patients with IVS > 16 mm.

Ten Tips and Tricks for Performing Alcohol Septal Ablation in Patients with Hypertrophic Obstructive Cardiomyopathy

Alcohol septal ablation (ASA) is an effective interventional therapeutic strategy to reduce or eliminate left ventricular outflow tract obstruction in patients with hypertrophic obstructive cardiomyopathy (HOCM). Although ASA was introduced 25 years ago, there are still no available guidelines to follow. Therefore, most interventional cardiologists rely on their own experience, which is often limited by a relatively low number of performed procedures. This paper presents ten tips and tricks to safe and effective ASA for HOCM.

Patients with hypertrophic obstructive cardiomyopathy after alcohol septal ablation have favorable long-term outcome irrespective of their genetic background

Background

The genetic background of patients with hypertrophic cardiomyopathy (HCM) treated with alcohol septal ablation (ASA) and its relationship to the outcomes are not known. We aimed to investigate whether the outcome of genotype positive (G+) patients differs from genotype negative (G-) patients treated with ASA.

Methods

We included 129 HCM patients (mean age 54±13 years) treated with ASA in a tertiary cardiovascular center and performed next generation sequencing (NGS) based genomic testing. All patients were followed-up three months after the procedure and yearly thereafter.

Results

A total of 30 (23%) HCM patients were G+ patients. At the 3-months follow-up, both groups of patients had similar left ventricular outflow tract PG (16.9±15.7 mmHg in G+ vs. 16.3±18.8 mmHg in G-, P=0.73) and symptoms (follow-up NYHA class 1.40±0.62 vs. 1.37±0.53, P=0.99, follow-up CCS class 0.23±0.52 vs. 0.36±0.65, P=0.36). The independent predictors of all-cause mortality were baseline interventricular septum (IVS) thickness (HR 1.12, 95% CI: 1.00-1.26, P=0.049) and age at the time of ASA (HR 1.11, 95% CI: 1.06-1.17, P<0.01). The adjusted all-cause mortality rate did not differ significantly between G+ and G- patients (P=0.52). The adjusted combined mortality event rate did not differ between both groups (P=0.78).

Conclusions

Despite more severe phenotype in G+ HCM patients, ASA is an equally effective treatment for LVOTO in G+ patients as it is for treating LVOTO in G- patients. The long-term outcome after ASA is similar in G+ and G- patients.

Current state of the roles of alcohol septal ablation and surgical myectomy in the treatment of hypertrophic obstructive cardiomyopathy

Hypertrophic cardiomyopathy is a genetically determined disorder resulting in left ventricular hypertrophy. In a majority of the estimated 20 million people affected worldwide, left ventricular outflow obstruction is present at rest or with provocation. The presence and degree of obstruction influence the symptomatic presentation, treatment strategies and prognosis of affected individuals. Pharmacologic therapy with beta-adrenergic blocking drugs and calcium channel blockers is the principal treatment strategy in symptomatic patients with left ventricular outflow obstruction but is ineffective in many patients. When symptoms of exertional shortness of breath, chest pain and/or syncope prove refractory to medical therapy and there is persisting left ventricular outflow obstruction, or when there is drug intolerance, septal reduction strategies (surgical myectomy and alcohol septal ablation) are quite effective. Selection of the optimal septal reduction strategy for a given patient has become controversial and is determined largely by the medical system providing treatment strategies for the patient. Regretably, there are no randomized trials comparing myectomy and ablation and none are anticipated. The comprehensive Hypertrophic Cardiomyopathy Guideline Statements published in 2011 and 2014 differ significantly with the earlier statement favoring surgical myectomy and the more recent statement giving equal class I status to the two septal reduction strategies in adult patients with drug-refractory symptoms. Recently published studies of long-term follow-up of patients after alcohol septal ablation in Europe, where surgical myectomy is rarely performed, confirm long-term safety and effectiveness with survival free of cardiac events exceeding 96% at 15 years. The lesser degree of discomfort and more rapid recovery associated with the minimally invasive catheter-based alcohol ablation procedure coupled with the recently published long-term safety data favor an increased use of this strategy in symptomatic adult patients with hypertrophic obstructive cardiomyopathy (HOCM).

Transcatheter septal ablation in hypertrophic obstructive cardiomyopathy: a technical guide and review of published results

Transcatheter alcohol septal ablation (ASA) treatment of symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM) is based on the existence and degree of intraventricular obstruction. Patients with significant gradient and symptoms who do not respond to optimal medical therapy are eligible to gradient reduction through a surgical (septal myectomy) or a transcatheter (alcohol septal ablation) septal reduction. The latter encompasses occlusion of a septal branch perfusing the hypertrophied septum, which is involved in the generation of obstruction, by injecting ethanol into the supplying septal branch(es). ASA has been established as a highly effective and safe method and has outnumbered the surgical gold standard. Although the technique is straightforward, patient selection and some technical details may influence the efficacy and safety of the procedure. The technique is based on echocardiographic contrast guidance, which allows accurate target septal branch selection and optimisation of the result. Published long-term results from high-volume centres have confirmed the effectiveness of ASA and have shown excellent survival, which is comparable to that in the general population. Choice and performance of the surgical or interventional treatment should be implemented in highly specialised centres in terms of a heart-team approach, taking notice of anatomic characteristics as well as comorbidities. Involvement of all cases in international registries may reveal the individual merits and indications for the surgical and interventional treatment in HOCM.

Alcohol septal ablation in patients with severe septal hypertrophy

OBJECTIVE

The current guidelines suggest alcohol septal ablation (ASA) is less effective in hypertrophic obstructive cardiomyopathy (HOCM) patients with severe left ventricular hypertrophy, despite acknowledging that systematic data are lacking. Therefore, we analysed patients in the Euro-ASA registry to test this statement.

METHODS

We compared the short-term and long-term outcomes of patients with basal interventricular septum (IVS) thickness <30 mm Hg to those with ≥30 mm Hg treated using ASA in nine European centres.

RESULTS

A total of 1519 patients (57±14 years, 49% women) with symptomatic HOCM were treated, including 67 (4.4%) patients with IVS thickness ≥30 mm. The occurrence of short-term major adverse events were similar in both groups. The mean follow-up was 5.4±4.3 years and 5.1±4.1 years, and the all-cause mortality rate was 2.57 and 2.94 deaths per 100 person-years of follow-up in the IVS <30 mm group and the IVS ≥30 mm group (p=0.047), respectively. There were no differences in dyspnoea (New York Heart Association class III/IV 12% vs 16%), residual left ventricular outflow tract gradient (16±20 vs 16±16 mm Hg) and repeated septal reduction procedures (12% vs 18%) in the IVS <30 mm group and IVS ≥30 mm group, respectively (p=NS for all).

CONCLUSIONS

The short-term results and the long-term relief of dyspnoea, residual left ventricular outflow obstruction and occurrence of repeated septal reduction procedures in patients with basal IVS ≥30 mm is similar to those with IVS <30mm. However, long-term all-cause and cardiac mortality rates are worse in the ≥30 mm group.

Effect of Institutional Experience on Outcomes of Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

The current American College of Cardiology Foundation/American Heart Association guidelines on hypertrophic cardiomyopathy state that institutional experience is a key determinant of successful outcomes and lower complication rates of alcohol septal ablation (ASA). The aim of this study was to evaluate the safety and efficacy of ASA according to institutional experience with the procedure.

METHODS

We retrospectively evaluated 1310 patients with symptomatic obstructive hypertrophic cardiomyopathy who underwent ASA and were divided into 2 groups. The first-50 group consisted of the first consecutive 50 patients treated at each centre, and the over-50 group consisted of patients treated thereafter (patients 51 and above).

RESULTS

In the 30-day follow-up, there was a significant difference in the occurrence of major cardiovascular adverse events (21% in the first-50 group vs 12% in the over-50 group; P < 0.01), which was driven by the occurrence of cardiovascular deaths (2.1% vs 0.4%; P = 0.01) and implanted pacemakers (15% vs 9%; P < 0.01). In the long-term follow-up (5.5 ± 4.1 years), the first-50 group was associated with a significantly higher occurrence of major adverse events (P < 0.01) and higher cardiovascular mortality (P < 0.01). Also, patients in the first-50 group were more likely to self-report dyspnea of New York Heart Association class III/IV (16% vs 10%), to have a left ventricular outflow gradient > 30 mm Hg (16% vs 10%) at the last clinical check-up (P < 0.01 for both), and a probability of repeated septal reduction therapy (P = 0.03).

CONCLUSIONS

An institutional experience of > 50 ASA procedures was associated with a lower occurrence of ASA complications, better cardiovascular survival, better hemodynamic and clinical effect, and less need for repeated septal reduction therapy.

Contemporary Septal Reduction Therapy in Drug-Refractory Hypertrophic Obstructive Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a complex and relatively common genetic cardiac disease that has been the subject of intense investigation for over 50 years. Most patients with HCM are asymptomatic, but some develop symptoms, often many years after the appearance of electrocardiographic or echocardiographic evidence of left ventricular hypertrophy. Symptoms due to the left ventricular outflow tract obstruction frequently worsen over time, requiring septal reduction therapy (SRT) despite optimal medical therapy. Percutaneous transluminal septal myocardial ablation (PTSMA) and surgical myectomy are collectively known as SRT. In this review, we will focus on the emerging concept and practical implication of SRT and the available evidence on either PTSMA or surgical myectomy in the literature.

Hypertrophic obstructive cardiomyopathy: what, when, why, for whom?

Hypertrophic cardiomyopathy is the most common genetic cardiovascular disorder and is associated with symptoms of heart failure and increased risk of sudden cardiac death. The most common condition is obstruction of the left ventricular outflow tract. Surgical septal myectomy and alcohol septal ablation are the 2 accepted modes of septal reduction therapy and are indicated when there are advanced symptoms and a peak left ventricular outflow gradient ≥50 mmHg. Advantages of alcohol septal ablation are limited groin approach, reduction of obstruction of the left ventricular outflow tract and functional improvement, but there are higher chances for intracardiac device implantation and residual obstruction. Septal myectomy offers very low mortality, absolute and immediate resolution of obstruction of the left ventricular outflow tract and survival comparative to a matched general population with almost negligible residual obstruction. It is recommended that patients with obstructive hypertrophic cardiomyopathy should be treated at experienced centres.

Alcohol Septal Ablation for Obstructive Hypertrophic Cardiomyopathy: A Word of Balance

The management of drug-refractory symptoms of obstructive hypertrophic cardiomyopathy has long been debated and is primarily centered on the choice between surgical myectomy and alcohol septal ablation. Decision making in these patients requires consideration of procedural risk, expertise and efficacy, and the long-term impact on patients' survival. Although there have been numerous reports on these procedures that may help guide decision making, these data continue to be self-reported and voluntary. Greater insight into the real-world experience for these therapies and how they should be applied in practice would be gained from mandatory reporting, akin to other multidisciplinary, transcatheter-based therapies.

Septal myectomy after failed septal alcohol ablation

Despite septal myectomy remaining the gold standard septal reduction therapy for hypertrophic obstructive cardiomyopathy (HOCM), there has been a disproportionate use of alcohol septal ablation (ASA) worldwide. Absolute resolution of left ventricular outflow tract (LVOT) obstruction with ASA is not achieved in a substantial proportion of patients. The mechanisms of failure from ASA are partially understood and described. Residual obstruction in hypertrophic cardiomyopathy is associated with worse clinical outcomes and mortality. There is a growing number of patients who present with significant residual gradients after ASA and require a rescue septal myectomy operation, which then carries an increased risk of perioperative complications and life-long sequelae. This contrasts with the excellent outcomes achieved by septal myectomy without previous percutaneous intervention. Despite complete resolution of obstruction in rescue myectomy, the outcomes remain compromised by the prior ASA.

Outcome of Alcohol Septal Ablation in Mildly Symptomatic Patients With Hypertrophic Obstructive Cardiomyopathy: A Long-Term Follow-Up Study Based on the Euro-Alcohol Septal Ablation Registry

Background

The long‐term efficacy and safety of alcohol septal ablation (ASA) in patients with highly symptomatic hypertrophic obstructive cardiomyopathy has been demonstrated. The aim of this study was to evaluate the long‐term outcomes of mildly symptomatic patients with hypertrophic obstructive cardiomyopathy treated with ASA.

Methods and Results

We retrospectively evaluated consecutive patients enrolled in the Euro‐ASA registry (1427 patients) and identified 161 patients (53±13 years; 27% women) who were mildly symptomatic (New York Heart Association [NYHA] class II) pre‐ASA. The median (interquartile range) follow‐up was 4.8 (1.7–8.5) years. The clinical outcome was assessed and compared with the age‐ and sex‐matched general population. The 30‐day mortality after ASA was 0.6% and the annual all‐cause mortality rate was 1.7%, which was similar to the age‐ and sex‐matched general population (P=0.62). A total of 141 (88%) patients had resting left ventricular outflow tract gradient at the last clinical checkup ≤30 mm Hg. Obstruction was reduced from 63±32 to 15±19 mm Hg (P<0.01), and the mean NYHA class decreased from 2.0±0 to 1.3±0.1 (P<0.01); 69%, 29%, and 2% of patients were in NYHA class I, II, and III at the last clinical checkup, respectively.

Conclusions

Mildly symptomatic hypertrophic obstructive cardiomyopathy patients treated with ASA had sustained symptomatic and hemodynamic relief with a low risk of developing severe heart failure. Their survival is comparable to the general population.