Transthoracic Doppler echocardiography is a valuable tool to measure coronary flow reserve (CFR) and detect in-stent restenosis (ISR) after percutaneous coronary angioplasty in selected series of patients.Objectives
To assess the usefulness of coronary flow reserve measured by echocardiography in detecting significant (≥70%) ISR of the left anterior descending coronary artery in a large unselected population.Methods
Two hundred and twenty-three patients (age 61 ± 10 years; 168 men) treated with left anterior descending stenting underwent CFR measurement by transthoracic Doppler echocardiography and venous adenosine infusion 24–72 h before control coronary angiography. Coronary-active drugs were continued, and patients with multiple risk factors and old anterior–apical myocardial infarction were included.Results
Significant ISR occurred in 56 patients (25%). Patients with ISR had higher basal coronary flow velocity (27 ± 10 cm/s vs. 24 ± 7 cm/s; P < 0.002) and lower CFR (1.5 ± 0.5 vs. 2.7 ± 0.6; P < 0.0001) than those without ISR. A linear relation was found between ISR and CFR (r = −0.73; P < 0.0001) and remained significant after adjustment for blood pressure and heart rate (r = −0.74; P < 0.0001). A CFR less than two identified significant ISR (sensitivity 88%, specificity 88%, area under the curve = 0.943; P < 0.001). In a multivariate model of CFR prediction, myocardial infarction and heart rate were slightly contributory (ß = −0.19, P < 0.01; ß = −0.16, P < 0.03, respectively), whereas ISR had a large influence (ß = −0.66; P < 0.0001). The inverse correlation between ISR and CFR persisted in patients with myocardial infarction (r = −0.64; P < 0.0001) and in those treated with β-blockers (r = −0. 71; P < 0.0001).Conclusion
Echocardiographic measurement of CFR detects significant left anterior descending ISR in unselected patients with multiple risk factors, old anterior–apical myocardial infarction, and taking β-blockers.