Clinical, hemodynamic, and functional variables affecting success rate of coronary flow velocity reserve detection during vasodilator stress echocardiography

AIM: Stress echocardiography (SE) with state-of-the-art imaging protocol allows a comprehensive assessment of regional wall-motion abnormalities and Doppler-based coronary flow velocity reserve (CFVR) in left anterior descending artery (LAD). We sought to assess the variables potentially impacting on success rate of SE with CFVR. METHODS AND RESULTS: In a single-center, prospective, observational study design, from 2007 to 2019, we enrolled 2989 consecutive patients (age 67 ± 12 years; 1723 men) referred for SE, without contrast, for chronic known (n = 1130) or suspected (n = 1859) coronary syndromes. Coronary flow velocity reserve was measured as stress/rest peak diastolic flow velocity. The same operator (LC) performed all examinations with the same machine (GE Vivid 7). Interpretable CFVR was obtained in 2808 patients (feasibility = 93.9%). Overall success rate was lowest (91.4%) in 2007-2008 and steadily rose to 97.8% in 2017-2019 (P for trend <.0001). Feasibility was excellent for men (93.7%) and women (94.3%) (P = .47) across all values of body mass index (BMI): <25 (P = .09), 25-29 (P = .84), and ≥30 (P = .23). At multivariable logistic regression analysis, women with BMI ≥ 30 (OR 1.94, 95% CI 1.14-3.29, P = .02), resting heart rate ≥77 beats/min (OR 2.25, 95% CI 1.64-3.11; P < .0001), and stress-induced ischemia in the LAD territory (OR 3.14, 95% CI 1.67-5.90; P < .0001) predicted unfeasible CFVR. CONCLUSION: Vasodilator SE with CFVR combined with wall-motion analysis is highly feasible also without contrast although with a slight decline in presence of high resting heart rate (reducing diastolic time essential for flow imaging), women with BMI ≥ 30 (increasing tissue thickness interposed between transducer and artery), and anterior ischemia (for underlying low-absent anterograde flow for severely stenotic or occluded LAD).