Prognostic Value of Coronary Flow Reserve Obtained on Dobutamine Stress Echocardiography and its Correlation with Target Heart Rate

Background:: Normal coronary flow velocity reserve (CFVR) (≥ 2) obtained in the left anterior descending coronary artery (LAD) from transthoracic echocardiography is associated with a good prognosis, but there is no study correlating CFVR with submaximal target heart rate (HR). Objective:: To evaluate the prognostic value of CFVR obtained in the LAD of patients with preserved (>50%) left ventricular ejection fraction (LVEF) who completed a dobutamine stress echocardiography (DSE), considering target HR. Methods:: Prospective study of patients with preserved LVEF and CFVR obtained in the LAD who completed DSE. In Group I (GI = 31), normal CFVR was obtained before achieving target HR, and, in Group II (GII = 28), after that. Group III (G III=24) reached target HR, but CFVR was abnormal. Death, acute coronary insufficiency, coronary intervention, coronary angiography without further intervention, and hospitalization were considered events. Results:: In 28 ± 4 months, there were 18 (21.6%) events: 6% (2/31) in GI, 18% (5/28) in GII, and 46% (11/24) in GIII. There were 4 (4.8%) deaths, 6 (7.2%) coronary interventions and 8 (9.6%) coronary angiographies without further intervention. In event-free survival by regression analysis, GIII had more events than GI (p 50%) e ecocardiograma sob estresse com dobutamina (EED) concluido, considerando a FC alvo submaxima. Metodos:: studo prospectivo de pacientes com FEVE preservada e RVFC obtida na ADA durante EED concluido. No Grupo I (GI=31), a RVFC adequada foi obtida antes de se atingir a FC alvo, e no Grupo II (G II=28), apos. O Grupo III (G III=24) atingiu a FC alvo, mas a RVFC foi inadequada. Foram considerados eventos: obito, insuficiencia coronariana aguda, intervencao coronariana, coronariografia sem intervencao subsequente e internamento hospitalar. Resultados:: Em 28 ± 4 meses, ocorreram 18 (21,6%) eventos, sendo 6% (2/31) no GI, 18% (5/28) no GII e 46% (11/24) no GIII. Foram 4 (4,8%) obitos, 6 (7,2%) intervencoes coronarianas e 8 (9,6%) coronariografias sem intervencao subsequente. Na sobrevida livre de eventos pela analise de regressao, GIII apresentou mais eventos do que GI (p < 0,001) ou GII (p < 0,045), nao havendo diferenca entre GI e GII (p = 0,160). Apos o ajustamento, foi mantida a diferenca apenas entre GIII e GI (p = 0,012). Conclusao:: Em pacientes com FEVE preservada e EED concluido, a RVFC adequada obtida antes da FC alvo associou-se ao melhor prognostico.