Abstract Background Coronary flow and myocardial contractile performance assessed by strain magnitude increase during a dobutamine stress echocardiogram (DSE). Normal coronary flow reserve (CFR) can be attained upon completion of a DSE at age-predicted maximum heart rate (HR) (HRmax = 220 - age)] or submaximal HR [(0.85) HRmax] or before completion (early CFR). Objective To ascertain the association between delta strain and HR in patients with early normal CFR. Methods This prospective study included patients whose normal CFR was obtained before the DSE was completed. Percentage of resting HR (%HRrest) = [(HRrest ÷ HRmax) 100]% and %HR CFR = [(HR at the time of CFR attainment) ÷ (HRmax) 100]% were recorded. Strain was assessed in the left ventricular region of interest, and delta strain was calculated as the difference between the measures obtained at HRrest and after the DSE was completed. Strain agreement analysis for HRrest, %HRrest, and %HR CFR was performed using the kappa coefficient. The Shapiro-Wilk test was used to assess data normality, and the Mann-Whitney test was used to compare the groups. A p-value < 0.05 was considered statistically significant. Results Strain measured -23.3% ± 4.3% at baseline and -31.1% ± 4.9% during the DSE. In delta strain > 8 absolute points, the ROC curves showed an area under the curve of 0.874 ± 0.07 for %HRrest (p = 0.001) and an area under the curve of 0.862 ± 0.07 for %HR CFR (p = 0.001). In delta strain > 8 points, %HRrest ≤ 42.6% of HRmax and %HR CFR ≤ 62.5% of HRmax showed an accuracy of 82.9% and 79.8%, respectively. Conclusion In this study, lower HRrest and HR at the time of CFR attainment had a good association with better myocardial contractile performance, according to the change in strain magnitude.

Resumo Fundamento: A reserva de velocidade de fluxo coronariano (RVFC) adequada (≥ 2) obtida na artéria descendente anterior (ADA) através do ecocardiograma transtorácico associa-se a bom prognóstico, mas não há estudo correlacionando-a com a frequência cardíaca (FC) alvo (submáxima). Objetivo: Avaliar o valor prognóstico da RVFC obtida na ADA de pacientes com fração de ejeção do ventrículo esquerdo (FEVE) preservada (>50%) e ecocardiograma sob estresse com dobutamina (EED) concluído, considerando a FC alvo submáxima. Métodos: studo prospectivo de pacientes com FEVE preservada e RVFC obtida na ADA durante EED concluído. No Grupo I (GI=31), a RVFC adequada foi obtida antes de se atingir a FC alvo, e no Grupo II (G II=28), após. O Grupo III (G III=24) atingiu a FC alvo, mas a RVFC foi inadequada. Foram considerados eventos: óbito, insuficiência coronariana aguda, intervenção coronariana, coronariografia sem intervenção 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%) óbitos, 6 (7,2%) intervenções coronarianas e 8 (9,6%) coronariografias sem intervenção subsequente. Na sobrevida livre de eventos pela análise de regressão, GIII apresentou mais eventos do que GI (p < 0,001) ou GII (p < 0,045), não havendo diferença entre GI e GII (p = 0,160). Após o ajustamento, foi mantida a diferença apenas entre GIII e GI (p = 0,012). Conclusão: Em pacientes com FEVE preservada e EED concluído, a RVFC adequada obtida antes da FC alvo associou-se ao melhor prognóstico.

Abstract 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 < 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). Conclusion: In patients with preserved LVEF and who completed their DSE, normal CFVR obtained before achieving target HR was associated with better prognosis.

FUNDAMENTO: A artéria torácica interna enxertada (ATIE) patente usualmente tem fração diastólica (FD)> 50% do fluxo. O estado funcional pode ser avaliado pelo índice de reserva coronariano (IRC). OBJETIVO: Avaliar, pela ecocardiografia e pelo Doppler em nível supraclavicular, a patência e o estado funcional da ATIE. MÉTODOS: Foram coletados prospectivamente e analisados os dados de 66 pacientes submetidos a ecocardiograma sob estresse com dobutamina (EED). O grupo I (GI) ocorreu com 49 ATIE sem estenose. No grupo II (GII) (10 ATIE) havia estenose significativa (> 50% e <100%). E no grupo III (GIII) (7 ATIE) a oclusão era de 100%. Foram avaliados diâmetros e espectros do Doppler das ATIE no repouso e EED. RESULTADOS: Considerando patência uma FD>50%, ocorreu em 49 ATIE (GI=40, GII=8 e GIII=1) no repouso e em 61 ATIE (GI=49, GII=10 e GIII=2) durante EED. Sensibilidade, especificidade, valor preditivo positivo (VPP), valor preditivo negativo (VPN) e acurácia foram, respectivamente, em repouso, 81%, 86% ,98%, 35 % e 82%; e no EED, 100%, 71%, 97%, 100% e 97%. As ATIE com FD>50% em repouso estavam patentes e as com FD<50% no EED tinham oclusão total. Considerando para bom estado funcional um IRC>1,8, isso ocorreu em 42 ATIE (39 do GI, 2 do GII e 1 GIII), verificando-se sensibilidade = 79%; especificidade = 85,7%; VPP = 94%; VPN = 59%; e acurácia = 80,9%. O IRC no GI foi maior (p=0,02) que em GII e GIII. CONCLUSÃO: Em nosso estudo, a avaliação não-invasiva da ATIE foi efetiva para verificar patência e estado funcional.

BACKGROUND: The patent internal thoracic artery graft (ITAG) usually has a diastolic fraction (DF) > 50% of the flow. The functional assessment can be evaluated by the coronary reserve index (CRI). OBJECTIVE: The objective was to evaluate the patency and functional status of the ITAG through echocardiography and Doppler. METHODS: Data from sixty-six patients who underwent dobutamine-stress echocardiography (DSE) were prospectively collected and analyzed. Group I (GI) had 49 ITAG without stenosis, Group II (GII), 10 ITAG with significant stenosis (> 50% and <100%) and Group III (GIII) had 7 ITAG with total occlusion. Diameters and Doppler spectrums from the ITAG at rest and during DSE were evaluated. RESULTS: Considering patency a DF >50%, it was observed in 49 ITAG (GI= 40, GII= 8 and GIII= 1) at rest and in 61 ITAG (GI=49, GII=10 and GIII=2) during DSE. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were respectively, 81%, 86%, 98%, 35% and 82%, and 100%, at rest and 71%, 97%, 100% and 97% in the DSE. The ITAG with DF>50% at rest were patent and the ones with DF<50% in the DSE presented total occlusion. Considering a CRI>1.8 for a good functional status, it was observed in 42 ITAG (39 from GI, 2 from GII and 1 from GIII), determining sensitivity=79%, specificity=85.7%, PPV=94%, NPV=59% and accuracy= 80.9%. The CRI in GI was higher (p= 0.02) than in GII or GIII. CONCLUSION: In our study, the non-invasive assessment of the ITAG was effective to verify the patency and the functional status.