Abstract 3678: Efficacy of Percutaneous Transluminal Septal Myocardial Ablation on the Von Willebrand Factor Structure’s Abnormalities in Patients with Hypertrophic Obstructive Cardiomyopathy
Background: Fluid high shear stress caused by severe aortic-valve stenosis was reported to alter von Willebrand factor’s (vWF) structure leading to hemostasis abnormalities and these abnormalities restored by aortic valve replacement. Hypertrophic obstructive cardiomyopathy (HOCM) causes high shear stress at intra left ventricular obstruction which may also lead hemostasis abnormalities. The purpose of this study is to examine whether large vWF multimer is reduced in HOCM and elimination of intra left ventricular obstruction by percutaneous transluminal septal myocardial ablation (PTSMA) can restores these hemostasis abnormalities.
Method and Result: We enrolled 9 consecutive HOCM patients (9 women, age 63.8±12.3 y/o) who underwent PTSMA. Western blot analysis was performed to quantify the vWF multimer. Large vWF multimer was estimated as percent changes of the densitograms of vWF multimer electropholasis compared to the normal control subjects. We also measured changes in serum hemoglobin, blood viscosity, vWF antigen level, ADP induced platelet aggregation threshold index, and the percentage of large vWF mulimer between the day before PTSMA and 2 weeks after PTSMA. In these patients, large vWF multimer was reduced before PTSMA compared with normal control subjects. Successful PTSMA significantly reduced mean pressure gradient at the obstruction from 73.8±35.1 mmHg to 19.4±21.5 mmHg (p<0.01), and improved NYHA class from 2.6±0.9 to 1.2±0.6 (p<0.01). PTSMA increased large vWF multimer and returned to normal range (78.9±12.8% vs. 98.0±11.5%. p<0.01). There were no significant differences in serum hemoglobin, blood viscosity, vWF antigen level and ADP induced platelet aggregation threshold index between pre and post-procedural values (12.0±1.9g/dl vs. 11.7±1.4g/dl [p=0.49], 3.7±0.49 vs. 3.82±0.47 [p=0.41], 167.8±19.4 vs. 164.0±29.4 [p=0.62] and 2.40±1.0 vs. 2.11±1.05 [p=0.80], respectively).
Conclusion: Significant deficit in large vWF multimer was confirmed in patients with symptomatic HOCM patients. PTSMA improves this abnormality as well as heart failure symptom by attenuating intra left ventricular obstruction causing high share stress.