Functional assessment of coronary arteries by poststenotic intravascular Doppler ultrasound

This study sought to delineate the impact of the rate pressure product on i ntraluminal Doppler velocity measurements and to determine the relation bet ween poststenotic vasodilator reserve and percent luminal obstruction in co ronary vessels. Twenty patients with single-vessel coronary disease were st udied prior to coronary angioplasty and at follow-up 6 months later. Intrac oronary velocity reserve after administration of adenosine was measured dis tal to the stenosis with a Doppler-tipped guide wire and was compared to qu antitative coronary angiography and adenosine myocardial perfusion scintigr aphy. The rate pressure product was confirmed as significant covariate (ANC OVA, p < 0.005) of intracoronary Doppler reserve. When normalized to rate p ressure product, poststenotic Doppler velocity reserve in stenosed arteries was significantly lower than in patent arteries as classified by quantitat ive coronary angiography (1.7 +/- 0.6 vs. 2.9 +/- 0.5, p < 0.001) and perfu sion scintigraphy (1.5 +/- 0.4 vs. 2.8 +/- 0.5, p < 0.001). Normalized Dopp ler velocity reserve showed a nonlinear but highly significant relation to percent area stenosis [y = 3.0.(1 - exp[0.081 (x - 100)]), p < 0.001]. When normalized Doppler velocity reserve was less than 2.0, coronary disease wa s identified with 95% specificity and 94% sensitivity in comparison to perf usion scintigraphy. Thus, in coronary arteries poststenotic Doppler reserve and percent area stenosis show a significant nonlinear relation. Doppler v elocity reserve when normalized to rate pressure product can be used to cha racterize the hemodynamic impact of coronary obstructions. Copyright (C) 20 00 S. Karger AG, Basel.