Abstract 2977: Coronary Small Vessel Disease is the Main Mechanism of Myocardial Ischemia in Fabry Cardiomyopathy
Introduction:Myocardial ischemia may occur in Fabry cardiomyopathy (FC). Its mechanism is still unknown.
Hypothesis:Coronary small vessel disease significantly contributes to myocardial ischemia and FC progression.
Methods: Coronary anatomy, flow and reserve were evaluated in 40 FC patients (MWT ≥ 13 mm, 25M/15F, mean age 43 ± 14 ys) symptomatic for angina (10), palpitations (8) or dyspnoea on effort (22). Cardiac studies included exercise stress test, SPECT imaging with 99Tc-sestamibi, coronary angiography with assessment of coronary flow and left ventricular (LV) endomyocardial biopsy. Biopsy samples were used for morphometric evaluation of intima and media thickness and % luminal area of transversely cut intramyocardial vessels and compared with 10 control biopsies.
Results: Coronaries were structurally normal in all showing slow-flow in the 10 patients with angina, but not in the other FC. In the 10 cases exercise stress test showed signs and/or symptoms of myocardial ischemia and SPECT was positive for stress-induced perfusion defects. Histology showed a remarkable lumen narrowing (≥ 75%) of most (> 50%/pt ) arterioles, due mainly to hypertrophy and proliferation of smooth muscle cells and partly to swelling and hyperplasia of endothelial cells, both engulfed by glycosphingolipids (Figure⇓). Perivascular fibrosis of severely affected vessels was a common feature. There was no correlation with patients age, sex and severity of LV hypertrophy .
Conclusions: Structural narrowing of intramural vessels is the main cause of slow flow and angina and a likely mechanism of disease progression in FC. It seems independent from patients age, sex and severity of LV hypertrophy.