The importance of left ventricular outflow tract obstruction in a large subset of patients with HCM with drug-refractory symptoms, as well as the value of septal reduction therapy (surgical myectomy or alcohol septal ablation), has been demonstrated. However, determining the precise cause of symptoms in the HCM patient, and specifically implicating outflow tract obstructive physiology as the predominant culprit, can be quite challenging. Accordingly, a detailed and comprehensive morphologic and physiologic evaluation of the HCM patient is of paramount importance to determine which patients may benefit most from septal reduction therapy. Patients should be considered for septal reduction therapy when (a) symptoms are clearly and primarily attributed to obstructive HCM despite optimal medical therapy; (b) symptoms encompass severe heart failure or angina (NYHA or CCS class III/IV), recurrent obstruction-related syncope, or recurrent clinical decompensation due to refractory paroxysmal atrial fibrillation; (c) a gradient ≥50 mmHg can be demonstrated on optimal medical therapy; and (d) obstruction is clearly dynamic and subvalvular, resulting mainly from septum-to-anterior mitral leaflet contact. More distal obstruction may also be present (i.e., mid-ventricular and/or apical), and can further inform the choice of SRT. Surgical myectomy has been the traditional gold standard invasive therapy that can address a multitude of pathologies in capable hands. Alcohol septal ablation (ASA) is a minimally invasive catheter-based alternative with less patient discomfort and more rapid recovery; however, because the procedure is limited by septal perforator location and trajectory, only patients with certain anatomic criteria are candidates. Importantly, both procedures have now evolved with a wealth of observational evidence to assure high efficacy and safety when performed in experienced centers. Evidence from nonrandomized studies suggests that ASA and surgical myectomy result in similar short- and long-term outcomes with respect to hemodynamic and functional improvements, with greater propensity for pacemaker placement with septal ablation that balances a higher early morbidity with surgical myectomy. Based on a comprehensive assessment of clinical symptoms, associated comorbidities, and echocardiographic, electrocardiographic, and angiographic features, some patients are better suited for myectomy, while others are better suited for ASA. This chapter reviews indications for septal reduction therapy and how to individualize the selection of the appropriate septal reduction procedure in clinical practice.

Indications for and Individualization of Septal Reduction Therapy

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发表日期：

2025年

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Srihari S. Naidu,
John S. Douglas,
Steve R. Ommen

摘要

The importance of left ventricular outflow tract obstruction in a large subset of patients with HCM with drug-refractory symptoms, as well as the value of septal reduction therapy (surgical myectomy or alcohol septal ablation), has been demonstrated. However, determining the precise cause of symptoms in the HCM patient, and specifically implicating outflow tract obstructive physiology as the predominant culprit, can be quite challenging. Accordingly, a detailed and comprehensive morphologic and physiologic evaluation of the HCM patient is of paramount importance to determine which patients may benefit most from septal reduction therapy. Patients should be considered for septal reduction therapy when (a) symptoms are clearly and primarily attributed to obstructive HCM despite optimal medical therapy; (b) symptoms encompass severe heart failure or angina (NYHA or CCS class III/IV), recurrent obstruction-related syncope, or recurrent clinical decompensation due to refractory paroxysmal atrial fibrillation; (c) a gradient ≥50 mmHg can be demonstrated on optimal medical therapy; and (d) obstruction is clearly dynamic and subvalvular, resulting mainly from septum-to-anterior mitral leaflet contact. More distal obstruction may also be present (i.e., mid-ventricular and/or apical), and can further inform the choice of SRT. Surgical myectomy has been the traditional gold standard invasive therapy that can address a multitude of pathologies in capable hands. Alcohol septal ablation (ASA) is a minimally invasive catheter-based alternative with less patient discomfort and more rapid recovery; however, because the procedure is limited by septal perforator location and trajectory, only patients with certain anatomic criteria are candidates. Importantly, both procedures have now evolved with a wealth of observational evidence to assure high efficacy and safety when performed in experienced centers. Evidence from nonrandomized studies suggests that ASA and surgical myectomy result in similar short- and long-term outcomes with respect to hemodynamic and functional improvements, with greater propensity for pacemaker placement with septal ablation that balances a higher early morbidity with surgical myectomy. Based on a comprehensive assessment of clinical symptoms, associated comorbidities, and echocardiographic, electrocardiographic, and angiographic features, some patients are better suited for myectomy, while others are better suited for ASA. This chapter reviews indications for septal reduction therapy and how to individualize the selection of the appropriate septal reduction procedure in clinical practice.