Assessment of colour flow imaging in the grading of valvular regurgitation

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Abstract
To assess the accuracy of colour flow imaging in the grading of valvular regurgitation, we studied 100 consecutive patients with angiographic mitral regurgitation (55), aortic regurgitation (35) or both (10). The etiology of valve regurgitation was rheumatic in 42 and non-rheumatic in 58 patients. For comparison, 28 subjects with no structural cardiac disease were studied. Mitral valve regurgitation was assessed with colour flow imaging by measuring the maximal regurgitant jet area and the maximal jet area normalized to left atrial area; aortic valve regurgitation was assessed from jet area and jet width normalized to ventricular outflow tract width. The best correlation between colour flow imaging and angiography was obtained with normalized measurements for both mitral (r = 0.82, P<0.0001) and aortic regurgitation (r = 0.94, P<0.0001). A proportion of patients and controls without angiographic regurgitation showed evidence of mild mitral (31% and 32%) and aortic (14% and 11%) regurgitation on colour flow imaging. There was a large overlap in the normalized colour flow measurements between angiographically mild and moderate mitral regurgitation: (43%); the overlap was greater when regurgitation was rheumatic in origin (45% ) rather than non-rheumatic (10%) (P<0.001). There was also overlap in the normalized colour flow findings in patients with angiographic aortic regurgitation, which was greater in rheumatic vs non-rheumatic disease. Knowledge of the etiology significantly improved the separation of all angiographic grades of aortic regurgitation using colour flow measurements (P = 0.006). These findings confirm the high sensitivity of colour flow imaging in the detection of valvular regurgitation and indicate that its accuracy is higher in patients with non-rheumatic than rheumatic heart disease.