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

Abstract

BackgroundNormal 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).ObjectiveTo 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.MethodsProspective 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.ResultsIn 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 < 0.001) and GII (p < 0.045), with no difference between GI and GII (p = 0.160). After adjustment, the only difference was between GIII and GI (p = 0.012).ConclusionIn patients with preserved LVEF and who completed their DSE, normal CFVR obtained before achieving target HR was associated with better prognosis.

Análise da Segurança e Exequibilidade do Ecocardiograma sob Estresse com Dobutamina em Dez Mil e Seis Exames de uma População Geral

“…Em publicações prévias, essas características foram verificadas no sexo feminino. 17,19 A PA sistólica, nas condições de repouso e estresse, foi maior nos exames positivos para isquemia, compatível com a condição de maior incidência de hipertensos nesse grupo. Quanto ao sexo, verificou-se maior PA sistólica no sexo masculino, tanto no repouso como no estresse.…”

“…16,17 Com a evolução dos protocolos, a atropina passou a ser administrada durante o quarto estágio ou após a metade do terceiro, a depender da FC alcançada ou por decisão do examinador. 18,19 A atropina foi administrada em bólus de 0,25 a 0,50 mg por minuto, podendo alcançar a dose cumulativa máxima de até 2 mg. Uma situação infrequente e importante, na qual se administraria a atropina em momento mais precoce, decorreria da necessidade de interromper a tendência à desaceleração sinusal em algum caso específico.…”

“…Ao final do exame, poderiam ser administrados 5 a 10 mg de metoprolol endovenoso para controle de isquemia e/ ou redução da FC. 1,3,5,9,16,[18][19][20][21][22][23] Como rotina do serviço, após o EED, o paciente aguardava em sala anexa por, pelo menos, 20 minutos, independente do resultado do exame.…”

Strain Magnitude Assessed at Rest and During Stress Echocardiography in Patients with Normal Coronary Flow Reserve

“…Based on the literature, CFR was calculated by dividing peak diastolic flow velocity obtained during the DSE by that recorded at baseline. 14,16,18,21,22,24 The aortic flow was recorded by conventional pulsed wave Doppler, with systole delimited by the period between the R wave on electrocardiogram and valve closure on Doppler. Subsequently, the center of the color tissue Doppler cone beam was placed as parallel as possible to the anterior wall of the LV, in the apical 2-chamber position.…”

“…Upon completion of Normal CFR can be attained upon completion of a dobutamine stress echocardiogram (DSE), or even at a lower heart rate (HR) than predicted for completion of the test (early CFR). 15,[18][19][20][21][22] Additionally, we have observed in practice that vigorous contractile responses during the DSE can be detected in patients with lower resting HR (HRrest) and in those in which normal CFR is attained at lower HRs. The actions of dobutamine, potentiated by the Gregg effect, are relevant to justify the intensity of left ventricular (LV) contractile response at low HRs, although other factors may modulate this response and contribute to its intensity.…”