Contribution of bradykinin receptor dysfunction to abnormal coronary vasomotion in humans
Abhiram Prasad, MBBS, MRCPa,
Syed Husain, MDa,
William Schenke, BSa,
Rita Mincemoyer, RNa,
Neal Epstein, MDa and
Arshed A. Quyyumi, MD, FRCP, FACCa
a Cardiology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
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Figure 1 Comparison of BK and ACH-induced microvascular dilation. Bars represent patients from the three tertiles of ACH responses: low (<70%, n = 23), medium (70–130%, n = 23) and high (>130%, n = 22) increase in blood flow compared with baseline.
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Figure 2 Effect of risk factors on ACH (30 µg/min) and SNP (40 g/min) induced coronary microvascular dilation measured as % change in coronary vascular resistance compared with baseline. *p < 0.05, **p  0.01 compared with 0 risk factors. By analysis of variance, p = 0.025 for ACH and p > 0.1 for SNP responses between groups.
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Figure 3 Effect of risk factors on bradykinin-induced coronary epicardial dilation (measured as % change in diameter) and microvascular dilation (measured as % change in resistance). No difference in responses between risk groups by analysis of variance.
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Figure 4 Bradykinin- (left) and acetylcholine- (right) mediated microvascular (top) and epicardial (bottom) vasomotion before (control solid circles with solid lines) and after L-NMMA (open circles with dashed lines, n = 20). *p = 0.03, **p = 0.003, ***p < 0.001 comparing control with L-NMMA. L-NMMA = L-NG monomethyl arginine.
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Figure 5 Bradykinin-induced coronary epicardial dilation in segments that constricted (n = 20) and those that dilated (n = 30) with pacing. The difference between responses was compared using analysis of variance.
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Figure 6 (Top panel) Bradykinin-mediated epicardial vasomotion in patients with serum ACE levels > median value of 9.9 U/ml (high ACE, n = 30) compared with those with levels below median (low ACE, n = 32). (Lower panel) Bradykinin-mediated epicardial vasomotion in patients with DD (n = 13) genotype compared with patients with the ID or II genotypes (n = 49). The comparison between groups by analysis of variance. ACE = angiotensin-converting enzyme.
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