To test the feasibility and utility of instituting centralized echocardiographic quality control during a multicenter study of regression of left ventricular hypertrophy in hypertension.Design and methods
The LIVE (Left Ventricular Hypertrophy: Indapamide Versus Enalapril) study is an ongoing multicenter, double-blind, controlled study of regression of echocardiographic left ventricular mass index in hypertensive patients with left ventricular hypertrophy (left ventricular mass indexes >100 g/m2 for women and >120 g/m2 for men) treated for 1 year with 1.5 mg indapamide sustained-release coated tablets versus 20 mg enalapril. A centralized evaluation committee has validated a prestudy sample echocardiogram from each center, and is now reviewing all videotapes recorded during this study for quality control; final results will be based on a further randomized blinded analysis by this centralized evaluation committee.Results
Since December 1994, 878 patients have been preselected (videoechocardiographic recordings sent for assessment), 645 selected (videoechocardiographic recordings validated), and 576 randomly allocated to treatment. After preliminary quality control, 27% (233) of baseline echocardiograms were rejected by our centralized evaluation committee, and 22% (142) of postinclusion echocardiographic measurements had to be repeated, mainly because they were of poor echogenic quality. Analysis of approved baseline echocardiograms for the first 274 randomly allocated patients with digitized data showed that there was a significant correlation between centralized evaluation committee and investigator calculations of left ventricular mass index (r = 0.76, P < 0.001), with consistently higher values for investigator calculations, independently of level of left ventricular mass index (correlation between difference and mean of investigator and centralized evaluation committee measurements, r = 0.08, P = 0.28). The mean difference was 8 ± 20 g/m2 (P < 0.001).Conclusion
Early results of the LIVE study quality control showed that real-time 'live', centralized echocardiographic reading was not only feasible, but also useful for avoiding unquantifiable echocardiograms and overestimation of left ventricular mass index. Thus, real-time, centralized echocardiographic quality control should be recommended for multicenter studies of regression of left ventricular hypertrophy.