P264 Alcohol septal ablation in hypertrophic obstructive cardiomyopathy with mitral insufficiency of mixed mechanism

Abstract

Alcohol septal ablation is a percutaneous intervention for hypertrophic obstructive cardiomyopathy, aiming to relieve symptoms, as an alternative to surgical myomectomy, in optimally treated but still symptomatic patients, with high surgical risk. We present the case of 65-year-old female, with persistently elevated blood pressure, presenting with severe dyspnea and angina on exertion and frequent episodes of paroxysmal nocturnal dyspnea. Clinical examination revealed an intense left parasternal systolic murmur. Electrocardiographic findings were sinus rhythm and negative T waves in V2-V6. Transthoracic echocardiography showed a small LV cavity with severe asymmetric left ventricular hypertrophy (maximum basal interventricular septum thickness of 26 mm), with important obstruction in the left ventricular outflow tract - resting gradient 77mmHg, provoked gradient 100mmHg. TOE evaluation of the mitral valve revealed significant mitral regurgitation, with intermitent telesystolic anterior motion of the anterior mitral leaflet and also P2 scallop prolapse. Further evaluation revealed a 60% stenosis of left anterior descending (LAD) artery of second segment, 60% stenosis of the left internal carotid artery, chronic renal disease (creatinine clearance 80ml/min), and moderate pulmonary hypertension. Although surgery was initially proposed to the patient, given the high operative risk (EUROSCORE II 8.45%) for a complete surgical procedure (myomectomy, mitral valve repair and coronary bypass), we attempted a stepwise approach to alleviate her symptoms. Intensive medical treatment improved blood pressure control while angioplasty of the LAD alleviated her angina. Echo-guided alcohol ablation of the interventricular septal wall was performed. Catheter-based contrast injection of a secondary septal branch of the LAD produced a subendocardial contrast in the contact area of anterior mitral valve leaflet; subsequently, embolizing the artery, producing an isolated necrosis at this level, with equalizing the pressure curves between LV and aorta. Postintervention, initial gradients were 50mmHg at rest, 100mmHg on postextrasystolic measurement. Systolic movement of the anterior leaflet maintained a mezotelesystolic pattern. At 3-months follow-up, LVOT gradients were 27/100mmHg, without any increase in pulmonary artery pressure, but with significant improvement of dyspnea. Further risk assessment by Holter ECG monitoring identified non-sustained ventricular tachycardia, so an ICD was implanted. The modest reduction in gradient was associated with significant clinical improvement in the patient’s symptomatology. This procedure has been refined in the last years, especially with the introduction of myocardial contrast echocardiography for better localizing the area at risk of infarction and to reduce the amount of alcohol used. Alcohol septal ablation may be part of a stepwise plan to improve symptoms, with lower procedural risks as compared to classic surgery.