Alcohol septal ablation in drug-refractory hypertrophic obstructive cardiomyopathy patient with multiple comorbidities

Abstract

Septal reduction therapy is an effective treatment for hypertrophic obstructive cardiomyopathy (HOCM). Alcohol septal ablation (ASA) is indicated for HOCM patients who are ineligible for surgical myectomy, but several tips exist for the management of high-risk patients with ASA. Here, we present a case of successful ASA in a HOCM patient with multiple comorbidities, including severe obesity, drug-refractory bronchial asthma, poorly controlled diabetes, and steroid-induced immunosuppression. Pre-procedural strict glycemic control, pre-treatment with corticosteroids for bronchospasm prevention, minimal puncture sites for device insertion, and myocardial contrast echocardiography-guided procedure contributed to the achievement of successful ASA. With careful periprocedural management, ASA is a safe and effective treatment option for drug-refractory HOCM, even in high-risk patients with multiple comorbidities.

Learning objective

Alcohol septal ablation can be a beneficial and safe treatment option for hypertrophic obstructive cardiomyopathy patients with multiple comorbidities, including severe obesity, drug-refractory bronchial asthma, poorly controlled diabetes, and steroid-induced immunosuppression. Detailed periprocedural management, including myocardial contrast echocardiography-guided procedure, is the key for achievement.

Introduction

Septal reduction therapy (SRT) is an effective nonpharmacological treatment for hypertrophic obstructive cardiomyopathy (HOCM). Surgical myectomy is the first-choice treatment for SRT. However, some patients are ineligible due to presence of comorbid conditions. Alcohol septal ablation (ASA) is an alternative method. Several tips exist for the management of high-risk patients with ASA. We present the successful ASA case of a 46-year-old female with HOCM who had multiple comorbidities including, severe obesity (body mass index 50.3 kg/m²), drug-refractory bronchial asthma, diabetes, and steroid-induced immunosuppression.

Case report

A 46-year-old female presented to our cardiology department with exertional dyspnea and chest pain. Transthoracic echocardiography (TTE) revealed left ventricular (LV) hypertrophy. However, a detailed evaluation was not performed because of the poor acoustic window caused by severe obesity. Cardiac magnetic resonance imaging (cMRI) revealed diffuse left ventricular wall thickening with systolic blood flow acceleration in the LV outflow tract (LVOT), which is consistent with HOCM (Fig. 1A, Video 1). The initiation of beta-blockers and calcium-channel-antagonists improved her symptoms. However, within the following four years, her symptoms gradually worsened [New York Heart Association (NYHA) class III]. The patient's body weight and mass index were 119 kg and 50.3 kg/m², while the blood pressure and heart rate were 141/75 mmHg and 53 bpm, respectively. Laboratory tests revealed elevated levels of N-terminal pro-brain natriuretic peptide (NT-pro BNP) (1607 pg/mL), fasting blood glucose (262 mg/mL), and hemoglobin (Hb) A1c (12.6 %). A 12‑lead electrocardiogram revealed sinus rhythm with LV strain pattern in the lateral leads (Online Fig. 1). The catheter-based peak pressure gradient of the LVOT was 75 mmHg at rest and 120 mmHg during provocation (Fig. 1B, C). Furthermore, transesophageal echocardiography revealed a LVOT peak pressure gradient of 90 mmHg at rest with moderate mitral regurgitation due to systolic anterior motion of mitral valve (Fig. 1D, Video 2). An endomyocardial biopsy of the right ventricular septum revealed myocyte hypertrophy, mild bundle disarray, and interstitial fibrosis. Administration of class IA antiarrhythmic drugs failed to improve the LVOT obstruction and symptoms. Therefore, non-pharmacological treatment approaches were considered.

Fig. 1.

Diagnosis of HOCM by multimodality imaging. (A) Four-chamber view of cine cMRI. An accelerated flow jet (red arrowheads) is observed at the LVOT. The catheter-based peak pressure gradient across the LVOT (double-headed arrows) is 75 mmHg at rest (B) and 120 mmHg after premature ventricular contraction (C). (D) Transesophageal echocardiography revealed peak pressure gradient across the LVOT as 90 mmHg at rest. (E) Chest X-ray after implantation of dual chamber pacemaker.

Ao, aorta; cMRI, cardiac magnetic resonance imaging; HOCM, hypertrophic obstructive cardiomyopathy; LA, left atrium; LV, left ventricle; LVOT, left ventricular outflow tract.

The patient had several episodes in her past medical history. She was diagnosed with primary obesity in her 20s. Drug-refractory bronchial asthma developed in her 30s that required multiple emergent hospitalizations. Long-term oral steroid therapy (dexamethasone 2 mg daily) was necessary to control her respiratory condition. Accordingly, multiple hospitalizations were required due to poor glycemic control caused by steroid-induced diabetes, as well as frequent bacterial infections, including venous catheter-associated infections, cellulitis, and subcutaneous abscess formation at the groin area, which required incision and/or drainage.

The current clinical guidelines for the management of HOCM recommend SRT (i.e. surgical myectomy or ASA) for drug-refractory HOCM [1]. In a case of HOCM ineligible for SRT, dual chamber pacing therapy can be an alternative option [1]. Due to her multiple comorbidities, including severe obesity and drug-refractory bronchial asthma, dual-chamber pacemaker (PM) implantation was selected first (Fig. 1E). Consequently, pacing therapy improved her chest pain and dyspnea (from NYHA class III to II). However, one month after implantation, the PM needed to be extracted due to device infection. After PM extraction, her symptoms worsened to NYHA class III, with syncope occurring along with hypotension due to LVOT obstruction under dehydrated conditions. Therefore, SRT was selected as the next treatment option. Due to severe obesity, bronchial asthma, and poor glycemic control, ASA was selected instead of surgical myectomy to avoid further complications. After strict management with intensive insulin therapy for four weeks of planned hospitalization, her fasting blood glucose and HbA1c levels were controlled at approximately 100 mg/dL and 8.3 %, respectively, and ASA was performed subsequently.

Pretreatment with corticosteroids was administered to prevent contrast media-induced bronchospasms. Owing to the narrow size of the vessels or a history of subcutaneous abscess formation in the groin area, the radial and femoral arteries were inappropriate for catheter insertion. Subsequently, a right brachial artery approach was selected. Additionally, a temporal pacing lead was placed in the right ventricle via the jugular vein in case of periprocedural atrioventricular block (AVB). The first and second septal branches of the left anterior descending (LAD) artery were selected for ethanol injection (Fig. 2A). The 2nd septal branch had three daughter vessels in the distal portion, therefore, a total four vessels were target for ablation. Contrast media injection through an over-the-wire (OTW) balloon catheter was performed to visualize the target ablation area of the septal myocardium, as assessed by TTE [i.e. myocardial contrast echocardiography (MCE)-guided procedure] (Fig. 2B, C). Note, the intracardiac echocardiography system was ready to use in case of poor visualization of septum by TTE. Then, ethanol was gently injected through the OTW balloon catheter. As transient AVB was observed during ethanol injection, the volume and speed of the ethanol injection were properly adjusted to avoid AVB progression (0.25 mL/min, total 6.8 ml/four target branches). Finally, coronary angiography revealed complete occlusion of the target branches without any injury to the other myocardial areas of the LAD (Fig. 2D). Subsequently, the LVOT pressure gradient at rest decreased from 72 mmHg to 21 mmHg. The peak serum creatine kinase level was 1042 IU/L. Postprocedural cMRI (13 days after ASA) revealed late gadolinium enhancement at the basal septum (Fig. 2E, F) and disappearance of the accelerated flow jet in the LVOT (Video 3), suggesting effective myocardial ablation. Electrocardiogram of post-ASA procedure showed transient complete atrioventricular block (CAVB) by 48 h after ASA, but CAVB was not observed thereafter. The temporal pacing lead was removed at the point of 96 h after ASA (Online Fig. 1). The patient's heart failure symptoms improved from NYHA class III to II, and the patient was discharged 13 days post-procedure without any complications. Six months after ASA, heart failure symptoms in this case were categorized as NYHA class II, the same level at the time of discharge. The NT-pro BNP level was maintained at approximately 700 pg/mL.

Fig. 2.

Improvement in left ventricular outflow tract obstruction by ASA. (A) Left CAG image before ASA (RAO-cranial). The target septal branches (S1 and S2) are indicated by white arrowheads. (B, C) Three-chamber view of transthoracic echocardiography during contrast medium injection into the septal branch [original image (B) and scheme (C)]. The vascular territory of the septal branch is clearly visualized in a high-echoic region (yellow arrowheads). (D) Left CAG image obtained after ASA (RAO-cranial). The S1 and S2 branches were completely occluded. (E, F) Late gadolinium enhancement images of cMRI after ASA [four-chamber (E) and short-axis (F)] (13 days after the procedure). Transmural late gadolinium enhancement is observed in the basal septum region (red arrowheads).

Ao, aorta; ASA, alcohol septal ablation; CAG, coronary angiography; cMRI, cardiac magnetic resonance imaging; LA, left atrium; LV, left ventricle; RAO, right anterior oblique; RV, right ventricle.

Discussion

Because of advancements in medicine and population aging, patients who have multiple comorbidities are increasing over time. To deal with such cases by invasive treatment procedures, deeper understanding of each comorbid condition and appropriate management strategies are required. The importance of such “tailored management” is being recognized. However, regarding ASA in HOCM patients with multiple comorbid conditions, there are few case reports mentioning the point. This is the reason why we present this case report.

In the present case of drug-refractory HOCM with multiple comorbidities, several risks for surgical myectomy were anticipated, including 1) perioperative respiratory adverse events (PRAE) due to drug-refractory bronchial asthma and severe obesity, and 2) surgical wound infection caused by severe obesity, steroid-induced immunosuppression, and poorly controlled diabetes. Patients with bronchial asthma are known to have an elevated risk of perioperative morbidity and mortality due to PRAE caused by bronchospasm and hypoxemia [2]. Severe obesity (i.e. class III obesity; body mass index >40 kg/m²) is also a risk factor for PRAE due to obesity hypoventilation syndrome [3]. Therefore, procedures with general anesthesia might be avoided as much as possible for cases like this. Poor perioperative glycemic control, long-term steroid use, and severe obesity synergistically increase the risk of surgical wound infection [4]. Indeed, this patient had several histories of bacterial infection involving venous catheter-associated infection, subcutaneous abscess formation following cellulitis, and device infection after PM implantation. Therefore, we believe that avoiding surgical myectomy was the appropriate choice for this case. Furthermore, a prior study revealed severe obesity is an independent risk factor for the progression of heart failure in patients with HOCM [5]. Therefore, the recent clinical guideline strongly recommends body weight control in patients with HOCM [5]. However, obesity treatment options including exercise and/or bariatric surgery were difficult to apply for this case. Therefore, the ASA procedure was selected as the most appropriate choice of management [1].

The most frequent complication of the ASA is CAVB. Previous cohort data reported that implantation of a permanent PM was necessary in 10 % of patients who underwent ASA [6]. Since the patient had a history of device infection, risk reduction for postprocedural infection was achieved by 1) strict glycemic control with intensive insulin therapy before ASA, 2) minimization of vessel puncture sites during the procedure, and 3) reduction of potential CAVB risk using the MCE-guided procedure (Fig. 2B, C). MCE-guided ASA has been reported to reduce the incidence of CAVB by visualizing the essential area of septal myocardium [7]. By applying several tips to the procedure, the ASA successfully reduced LVOT obstruction and symptoms without any complications in the present patient who has multiple comorbidities.

Because of medical advances and an aging population as mentioned, clinicians are now faced with the situation for evaluating the applicability of invasive treatment strategies in patients with multiple comorbid conditions. Thus, more detailed risk stratification criteria have been developed in several fields. For instance, the Society of Thoracic Surgeons risk score and EuroSCORE II are widely used for the risk stratification of open heart surgery. However, such risk stratification has not been established in patients who are eligible for ASA. By accumulating cases, establishing a comprehensive risk stratification strategy for ASA is warranted.

Conclusion

With careful periprocedural management, ASA is a safe and effective treatment option for drug-refractory HOCM, even in high-risk patients with multiple comorbidities.

The following are the supplementary data related to this article.

Video 1

cMRI finding in the patient with hypertrophic obstructive cardiomyopathy before alcohol septal ablation procedure. Four-chamber view of cine cMRI. An accelerated flow jet at left ventricular outflow tract was observed.

cMRI, cardiac magnetic resonance imaging.

Video 2

TTE finding in the patient with hypertrophic obstructive cardiomyopathy before alcohol septal ablation procedure. Three-chamber view of TTE showed mitral regurgitation flow and systolic anterior motion of mitral anterior leaflet.

TTE, transesophageal echocardiography.

Video 3

cMRI finding in the patient with hypertrophic obstructive cardiomyopathy after ASA procedure. Four-chamber view of cine cMRI. An accelerated flow jet at left ventricular outflow tract disappeared after ASA.

ASA, alcohol septal ablation; cMRI, cardiac magnetic resonance imaging.

Online Fig. 1

Serial change in 12‑lead electrocardiogram before and after ASA.

ASA, alcohol septal ablation.

Consent

The authors confirm that written consent for submission and publication of this case report has been obtained from the patient in line with COPE guidance.

Funding

None

Declaration of competing interest

The authors state that they have no conflict of interest (COI).