Targeted septal branch microcirculatory embolization with tris-acryl gelatin microspheres in hypertrophic obstructive cardiomyopathy

Abstract

Abstract Background Alcohol septal ablation (ASA) has been shown to be an effective treatment in patients with hypertrophic obstructive cardiomyopathy (HOCM) who are refractory to medical treatment. ASA may cause some life-threatening complications including conduction disturbances, hemodynamic compromise, ventricular arrhythmias, distant and massive myocardial necrosis. Tris-acryl gelatin microspheres provide consistent and predictable results for effective targeted microcirculatory embolization. Purpose We aimed to report our initial experience in tris-acryl gelatin microspheres for septal ablation in HOCM. Methods Microspheres are biocompatible, hydrophilic, non-resorbable microspheres which are available in a range of calibrated sphere sizes. In our method, after the cannulation of the left anterior descending by a 6F-7F guiding catheter, a 0.014-inch guidewire is introduced through the catheter and advanced into the septal branch. This septal artery is selectively cannulated with a 4F catheter over the guidewire. Selective angiography of the septal artery is performed to show the anatomy and collateral branches to other coronary arteries. Contrast echocardiography is performed to make sure that the pertinent septal artery is the target vessel supplying the hypertrophied septum. A microcatheter is then advanced deep enough into the septal artery through the 4F catheter. Microspheres/contrast solution infused slowly under fluoroscopic guidance into the targeted septal branches initially using coronary arteriolar sized small particles (diameter 100–300 μm); then the particle size was stepped up to larger particles (diameter 300–500 μm) until a complete block of the arteriolar flow is achieved. Results Septal ablation with tris-acryl gelatin microspheres was performed in 6 patients (mean age = 47.8±11.5; 5 males). Immediately after the procedure peak left ventricular outflow (LVOT) gradient reduced significantly both for direct catheter (69.0±13.8 vs. 8.2±3.7 mmHg, P<0.001) and Doppler echocardiographic measurements (78.8±19.9 vs. 12.0±5.1 mmHg, P<0.001). Post-procedure peak serum CK- MB fraction concentration was 82±22 ng/ml (reference range is 0 - 4.9 ng/mL) and peak serum troponin T concentration was 1.2 ng/ml [(interquartile range, 0.4–1.4), (reference range is 0 - 0.017 ng/mL)]. LVOT tract gradient reduction persisted after 6 months follow-up. There was no significant complication during the procedure and within a 6 months follow-up period. Conclusions The novel strategy by targeted septal branch microcirculatory embolization with tris-acryl gelatin microspheres seems to be an efficient and safe approach to HOCM. Further experience is needed in order to assess the long-term efficacy and safety of this technique. Funding Acknowledgement Type of funding source: None