Abstract 10904: Single-Wire Pressure and Flow Velocity Measurement to Quantify Microvascular Dysfunction in Patients With Coronary Vasospastic Angina
Background: We have shown that abnormal vascular functions of the epicardial coronary arteries, including endothelial dysfunction and vascular smooth muscle dysfunction, play pivotal roles in the pathogenesis of vasospastic angina (VSA). Contrary to epicardial artery, however, coronary microvascular (MV) function in pts with VSA has not been fully understood.
Methods: According to acetylcholine provocation tests, stable pts with suspected angina presenting nonobstructive coronary arteries (<50% diameter) in coronary angiography (42 pts [29 men,13 women, 61.4±11.2 years]) were divided into 2 groups; the VSA group of 21 pts and the non-VSA group of 21 pts. To evaluate directly coronary MV dysfunction, a velocity-based index of hyperemic MV resistance (h-MRv) was measured using a dual-sensor (doppler velocity and pressure)-equipped guidewire (Combowire, Volcano Therapeutics, Inc., Rancho Cordova, CA), and the guidewire-derived hemodynamic parameters, including fractional flow reserve (FFR) and coronary flow reserve (CFR), were compared between the 2 groups.
Results: There were no significant differences in clinical demographics including potential factors affecting MV function (e.g. diabetes) between the groups. Although FFR was comparable between the 2 groups reflecting the absence of significant epicardial coronary obstruction (0.87±0.08 in VSA group vs. 0.89±0.06 in non-VSA group, p=0.47), h-MRv was significantly elevated in the VSA group compared with non-VSA group (2.08±0.80 vs. 1.57±0.52, p=0.04). CFR was within the normal range without between-group difference (2.13±0.97 vs. 2.39±0.88, p=0.41). Coronary vasospasm and interventricular septal thickness were significantly associated with MV dysfunction (defined as ≥ median value of h-MRv [1.60]) in univariate analysis, and multivariate logistic regression analysis also showed that coronary vasospasm tended to predict MV dysfunction (odds ratio, 3.5; 95% confidence interval, 0.73-16.78; p=0.12).
Conclusion: Compared with non-VSA pts, MV function was impaired in pts with VSA, whereas CFR was maintained within normal range in both groups. In vivo assessment of h-MRv was a promising index of MV dysfunction in pts with VSA.
- © 2013 by American Heart Association, Inc.