RESUMEN
We assessed coronary flow reserve using transesophageal Doppler echocardiography in patients with coronary artery disease. The study included 33 coronary artery disease patients who were undergoing coronary arteriography. The blood flow velocities of the left anterior descending artery before and after intravenous infusion (0.56 mg/min for 4 min) of dipyridamole were recorded using transesophageal Doppler echocardiography. Fourteen normal healthy individuals, matched for age, served as a control group. The index of coronary flow reserve, i.e. the ratio of dipyridamole to baseline maximum diastolic velocity, was calculated. Maximal coronary flow reserve in coronary artery disease patients was significantly lower than in the control group (1.4+/-0.2 vs. 2.8+/-0.3, P<0.001). The coronary artery disease patients were classified into three groups: Group A included 10 patients with <50% left anterior descending artery stenosis; Group B included seven patients with 50-69% left anterior descending artery stenosis; 16 patients with >70% left anterior descending artery stenosis constituted Group C. The maximum coronary flow reserve was significantly different for A vs. B and A vs. C. (A, 1.77+/-0.18; B, 1.51+/-0.1; C, 1.28+/-0.24). A strong and significant correlation was found between the maximum coronary flow reserve and the degree of proximal left anterior descending artery stenosis (r=0.78, P<0.001). Coronary artery disease patients without left anterior descending artery stenosis on the arteriogram exhibited lower maximum coronary flow reserve compared to the control subjects (1.78+/-0.19 vs. 2.8+/-0.3, P=0.000).
Asunto(s)
Circulación Coronaria/fisiología , Enfermedad Coronaria/diagnóstico por imagen , Enfermedad Coronaria/fisiopatología , Ecocardiografía Transesofágica , Análisis de Varianza , Velocidad del Flujo Sanguíneo/efectos de los fármacos , Estudios de Casos y Controles , Circulación Coronaria/efectos de los fármacos , Dipiridamol , Femenino , Humanos , Masculino , Persona de Mediana Edad , VasodilatadoresRESUMEN
Evaluation of coronary microvascular function can be obtained through coronary flow reserve measurements. The aim of this study was to evaluate the coronary microvascular function by using transesophageal-Doppler echocardiographic assessment of coronary flow reserve. The study included 32 normotensive patients with type II diabetes mellitus (group A) of short duration (6.1+/-3.8 years) aged 55.4+/-9.4 years and 14 healthy volunteers matched for age, gender and BMI (group B). No patients had clinical evidence of coronary artery disease and all of them produced a negative recent stress ECG test. Excluded from the study were patients with anemia, left ventricular hypertrophy, arrhythmia, congenital, or acquired structural heart disease. All subjects underwent transesophageal-Doppler echocardiography. Satisfactory coronary blood flow velocity recordings could be obtained from the initial segment of the left anterior descending coronary artery in healthy volunteers and in 27 patients at baseline and 2 min after dipyridamole infusion (0.56 mg/kg, for 4 min). In the remaining 5 patients no satisfactory recordings were available. The indexes of coronary flow reserve, i.e. the ratios of dipyridamole over basal maximum and mean diastolic velocities were calculated. Dipyridamole/rest maximal coronary reserve (Table 3) was 1.946+/-0.743, while this ratio for the mean diastolic velocity was 1.969+/-0.805 in group A. The respective values for group B, were 2.811+/-0.345 (P=0.000 vs. group A) and 2.914+/-0.303 (P=0.000 vs. group A). Thus, the increase in coronary flow reserve although present in both groups, it was more impressive in the normal group. Multiple regression logistic analysis of: age, sex, smoking, glucosylated hemoglobin, duration of diabetes and type of therapy, did not show any correlation of these parameters with the above ratios. This study shows that coronary flow reserve, as measured with transesophageal echocardiography-Doppler, is severely impaired in normotensive patients with type II diabetes, with relatively short duration of the disease.
Asunto(s)
Circulación Coronaria , Diabetes Mellitus Tipo 2/diagnóstico por imagen , Ecocardiografía Doppler , Ecocardiografía Transesofágica , Factores de Edad , Velocidad del Flujo Sanguíneo/efectos de los fármacos , Índice de Masa Corporal , Estudios de Casos y Controles , Circulación Coronaria/efectos de los fármacos , Vasos Coronarios/diagnóstico por imagen , Vasos Coronarios/efectos de los fármacos , Vasos Coronarios/fisiopatología , Diabetes Mellitus Tipo 2/dietoterapia , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/fisiopatología , Diástole , Dipiridamol , Electrocardiografía , Prueba de Esfuerzo , Femenino , Hemoglobina Glucada/análisis , Humanos , Modelos Logísticos , Masculino , Microcirculación/efectos de los fármacos , Persona de Mediana Edad , Factores Sexuales , Fumar/fisiopatología , Factores de Tiempo , VasodilatadoresRESUMEN
The aim of this study was to assess the value of adenosine (A) and the combination of nitroglycerin (N) with dobutamine (D) stress echocardiography (SE) in the identification of viable myocardium. The clinical and electrocardiographic (ECG) effects of both tests were also evaluated. Fifty-two coronary artery disease patients, aged 56.4 +/- 8 years, with left ventricular dysfunction due to a previous myocardial infarction (mean ejection fraction: 49 +/- 8%) were included in the study. Cardiac catheterization was performed in all patients before A (140 micrograms/kg/minute for five minutes) and the combination of N with D (5-10 micrograms/kg/minute) stress echocardiography. On the echocardiogram, the left ventricle was divided into 16 segments and wall motion was graded semiquantitatively from 1 (normal) to 4 (dyskinesia). The echocardiographic index was also estimated. A segment was considered viable during A infusion when resting asynergy showed deterioration of one grade or more. In contrast, segmental viability was considered to be present during the combination of N with D infusion when resting asynergy showed improvement of one grade or more. A thallium 201 single photon emission computed tomography (SPECT) with reinjection was performed as reference standard for the identification of viable myocardium. Stress echocardiography during infusion of A was associated with short-duration angina attacks in 3 (5.8%) patients and transient complete atrioventricular (AV) block in 1 (1.9%), whereas during the combination of N with D infusion, 6 (11.5%) patients experienced ventricular bigeminy lasting for a short period. ST segment elevation greater than 1 mm was recorded in those leads having a Q wave, in 19 (36.5%) patients. In 10 of these 19 (52.6%), viable myocardium was present in SPECT, as it was in 33 patients (63.5%) having no ST segment elevation (P = NS). Of a total of 832 segments that were graded during A-SE, 276 exhibited resting asynergy and the remaining 556 had normal motion and thickening at rest. The echocardiographic index during A infusion increased from 1.52 +/- 0.22 to 1.71 +/- 0.24 (P < 0.001), whereas during D and N infusion it decreased from 1.53 +/- 0.31 to 1.30 +/- 0.42 (P < 0.001). With SPECT considered as the gold standard for the identification of viable myocardium, sensitivity, specificity, and positive and negative predictive values of A-SE in detecting viable myocardium were 54%, 86%, 65% and 80%, respectively. The respective values for the combination of nitroglycerin with D-SE were 91%, 89%, 78%, and 96%, respectively. Stress echocardiography during A, and the combination of N with D, constitute safe methods in the identification of viable myocardium. The detection of ST segment elevation in the ECG leads with a Q wave during the combined infusion of nitroglycerin and dobutamine is not related to the presence of viable myocardial tissue. The A-SE provide moderate diagnostic accuracy, while the combination of N with D during SE is much superior in detecting viable myocardium.