Coronary Flow Velocity Reserve during Dobutamine Stress Echocardiography

Background: A coronary flow velocity reserve (CFVR) >= 2 is adequate to infer a favorable prognosis or the absence of significant coronary artery disease. Objective: To identify parameters which are relevant to obtain CFVR (adequate or inadequate) in the left anterior descending coronary artery (LAD) during dobutamine stress echocardiography (DSE). Methods: 100 patients referred for detection of myocardial ischemia by DSE were evaluated; they were instructed to discontinue the use of beta- blockers 72 hours prior to the test. CFVR was calculated as a ratio of the diastolic peak velocity (cm/s) (DPV) on DSE (DPV- DSE) to baseline DPV at rest (DPV- Rest). In group I, CFVR was < 2 and, in group II, CFVR was >= 2. The Fisher's exact test and Student's t test were used for the statistical analyses. P values < 0.05 were considered statistically significant. Results: At rest, the time (in seconds) to obtain Doppler in LAD in groups I and II was not different (53 +/- 31 vs. 45 +/- 32; p=0.23). During DSE, LAD was recorded in 92 patients. Group I patients were older ( 65.9 +/- 9.3 vs. 61.2 +/- 10.8 years; p=0.04), had lower ejection fraction (61 +/- 10 vs. 66 +/- 6%; p=0.005), higher DPV-Rest (36.81 +/- 08 vs. 25.63 +/- 06cm/s; p<0.0001) and lower CFVR (1.67 +/- 0.24 vs. 2.53 +/- 0.57; p<0.0001), but no difference was observed regarding DPVDSE (61.40 +/- 16 vs. 64.23 +/- 16cm/s; p=0.42). beta-blocker discontinuation was associated with a 4-fold higher chance of a CFVR < 2 (OR=4; 95% CI [1.171- 13.63], p= 0.027). Conclusion: DPV-Rest was the main parameter to determine an adequate CFVR. beta-blocker discontinuation was significantly associated with inadequate CFVR. The high feasibility and the time to record the LAD corroborate the use of this methodology.(Arq Bras Cardiol. 2014; 102(2): 134- 142)