[Transcoronary ablation of septal hypertrophy (TASH): a 5-year experience]

From 1991 to 1993, our group carried out extensive studies in the development of a new catheter-interventional concept of treatment for HOCM and suggested in 1994 the injection of absolute ethanol into the first major septal branch using the common PTCA technique. This approach was first used therapeutically by Sigwart in London and by our group in Bielefeld. Based on rhythmologic studies of other authors we suggested the designation Transcoronary Ablation of Septal Hypertrophy (TASH). Since 1995, an estimated 1000 patients (about 600 from Germany) in some 20 countries have been treated by this method. In 1997 a national multicenter TASH-registry was created by the German Cardiac Society. During the last five years extensive studies have been performed by different groups. Significant clinical and hemodynamic improvements were consistently found. This was true for both young and old patients, for patients with resting gradient and with provocable gradient. Clinical improvement (rate of improved patients about 90%) was seen under conditions of rest and stress, as well as during long-term follow-up. Specifically, there was a significant decrease of functional class, a reduced rate of syncope, and a reduced degree of mitral insufficiency. Exercise capacity, oxygen uptake and the cardiac index increased, intraventricular gradient, the end diastolic pressure of the left ventricle and the left atrial size decreased. Also there was a decrease in the septal thickness with increase in the cross sectional area of the outflow tract and with local contraction disorder. PET examination showed an ablation induced local myocardial defect. There was also evidence for improved diastolic function. Electrophysiological and Holter monitor studies indicated no increased arrhythmogenicity. The prognosis seems to be improved. Histologically, an atypical infarct pattern was found, i.e., the common round cell infiltration and the fibrotic process were surrounding but not penetrating the alcohol induced myocardial center of necrosis. The in-hospital mortality rate amounts to about 1.8%. The rate of permanent total av-block after TASH is less than 10%. In 15% a second TASH is necessary. In summary, during the last five years TASH has become a promising new catheter interventional therapy for HOCM, which compares favorably with surgical treatment. In experienced centers it has become a routinely performed procedure. The indication should be limited to severely symptomatic patients with typical (subaortic) HOCM. Further careful clinical examinations after TASH are required. All patients should be enrolled into a registry. TASH also constitutes a new area for comprehensive clinical research.