Key result
HCM is linked to ~40% lower CFR despite preserved endothelium-dependent vasodilation.
Why the study?
Coronary flow reserve is decreased in patients with hypertrophic cardiomyopathy, but it is unclear whether coronary endothelial function is impaired.
Is coronary endothelial function impaired in patients with hypertrophic cardiomyopathy compared to controls?
Case-Control (n=25)
No
Is coronary endothelial function impaired in patients with hypertrophic cardiomyopathy compared to controls?
Absolute Event Rate: 267% vs 447%
p-value: p=<0.01
Endothelium-dependent vasodilation of the epicardial and resistance coronary arteries is preserved in patients with hypertrophic cardiomyopathy despite decreased coronary flow reserve.
It is well known that coronary flow reserve (CFR) is decreased in patients with hypertrophic cardiomyopathy (HCM), but it is unclear whether coronary endothelial function is impaired. Coronary endothelial function and CFR in the coronary macro- and microcirculation was evaluated in 14 patients with HCM and 11 control subjects. Acetylcholine (ACh), bradykinin (BK) and papaverine were infused into the left coronary artery. Coronary cross-sectional area was determined by quantitative coronary angiography and coronary blood flow (CBF) was determined by the product of the coronary cross-sectional area and CBF velocity measured by an intracoronary Doppler guidewire. Acetylcholine at 100 microg induced diffuse coronary spasms of the left anterior descending coronary arteries in 3 of the patients with HCM. The changes in the diameter of the left anterior descending coronary artery and the increases in CBF induced by BK (0.2, 0.6, and 2.0 microg/min) did not differ between the 2 groups. CFR was lower in the HCM group than in the control group (p<0.01). Moreover, the ratio of BK-induced CBF increase to papaverine-induced CBF increase was comparable between the 2 groups. Endothelium-dependent vasodilation of the epicardial and resistance coronary arteries induced by BK was preserved despite the decreased CFR in patients with HCM.
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Yokohama et al. (2002) conducted a case-control in Hypertrophic Cardiomyopathy (n=25). Hypertrophic cardiomyopathy vs. Control subjects with atypical chest pain and normal coronary arteries was evaluated on Coronary flow reserve (CFR), calculated as papaverine-induced coronary blood flow divided by basal coronary blood flow (p=<0.01). Patients with hypertrophic cardiomyopathy had significantly lower coronary flow reserve compared to controls (267% vs 447%, p<0.01), but demonstrated preserved endothelium-dependent vasodilation in response to bradykinin.
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