Covered Stent Septal Ablation for Hypertrophic Obstructive Cardiomyopathy
Initial Success but Ultimate Failure Resulting From Collateral Formation
A 76-year-old woman had syncope and exertional dyspnea. A systolic murmur was noted. An echocardiogram showed hypertrophic obstructive cardiomyopathy, with septal thickness 18 mm and peak left ventricular outflow tract (LVOT) gradient 78 mm Hg (Figure 1A). Coronary arteriography demonstrated mild coronary atherosclerosis, with mild stenosis of the proximal left anterior descending (LAD) coronary artery involving the first septal branch creating an unfavorable angle of entry into this branch (Figure 2A). Attempts to catheterize the first septal branch with an angioplasty balloon catheter for intracoronary administration of ethanol were unsuccessful. As an alternative to ethanol ablation, the septal branch was occluded with a covered stent placed in the proximal LAD (Figure 2B). The patient had nausea without chest discomfort. Peak creatinine kinase was 363, with MB index 14%. Peak gradient was immediately reduced to 15 mm Hg (Figure 1B).
The patient subsequently had “6 glorious months,” feeling as though she were “25 years old.” Three months after covered stent placement, peak LVOT gradient was 21 mm Hg (Figure 1C). Her initial symptoms, however, subsequently returned. Ten months after covered stent placement, peak LVOT gradient was 97 mm Hg (Figure 1D). Coronary arteriography showed collateralization of the occluded septal branch from the right coronary artery (Figure 3). She underwent surgical septal myectomy.
We postulate that the initial success of the covered stent ablation, despite only a small amount of myocardial necrosis, was due to myocardial ischemia progressing to hibernation. Collateral development ultimately caused relief of ischemia and return of the gradient and related symptoms. This case supports the need to directly cause necrosis with ethanol in patients undergoing septal ablation.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
Circulation encourages readers to submit cardiovascular images to the Circulation Editorial Office, St Luke’s Episcopal Hospital/Texas Heart Institute, 6720 Bertner Ave, MC1-267, Houston, TX 77030.