Diastolic dysfunction as a predictor of weaning failure: A systematic review and meta-analysis.

PURPOSE: Weaning failure and prolonged mechanical ventilation are associated with increased morbidity, cost of care, and high mortality rates. In the last few years, cardiac performance has been recognized as a common etiology of weaning failure, and growing evidence suggests that left ventricular diastolic dysfunction is a key factor that determines weaning outcomes. Therefore, we performed a systematic review and a meta-analysis to evaluate whether diastolic dysfunction in the critically ill patient subjected to mechanical ventilation is an independent predictor of weaning failure. MATERIALS AND METHODS: We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, LILACS, Google Scholar, and ClinicalTrials.gov from inception to September 2014, along with conferences proceeding from January 2005 through September 2014, and included Observational Studies and Randomized Clinical Trials evaluating predictors of weaning failure. RESULTS: Ten studies were included in the systematic review; and 7, in the meta-analysis (6 observational studies and 1 randomized controlled trial). Patients who developed weaning failure had a higher E/e' ratio when compared with those who did not (mean difference, 2.65; 95% confidence interval, 0.52-4.79; P= .01); however, there was no difference in the E/A ratio (mean difference, 0.07; 95% confidence interval, -0.04 to 0.18; P= .22). Both the E/e' and E/A ratios were associated with weaning-induced pulmonary edema at the end of a spontaneous breathing trial. CONCLUSION: A higher E/e' ratio is significantly associated with weaning failure, although a high heterogeneity of diastolic dysfunction criteria and different clinical scenarios limit additional conclusions linking diastolic dysfunction with weaning failure.

Head-to-head comparison of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia in an animal model of coronary artery stenosis.

To compare the sensitivity of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia we produced a physiologically significant stenosis in the left circumflex artery of 14 open-chest dogs (range: 50 to 89% reduction in luminal diameter). In each study, dobutamine (5 to 40 microg kg(-1) min(-1) in 3-min stages) and pacing (20 bpm increments, each 2 min, up to 260 bpm) were performed randomly, and then followed by dipyridamole (up to 0.84 mg/kg over 10 min). The positivity of stress echocardiography tests was quantitatively determined by a significant (P<0.05) reduction of or failure to increase absolute and percent systolic wall thickening in the stenotic artery supplied wall, as compared to the opposite wall (areas related to the left anterior descending artery). Systolic and diastolic frozen images were analyzed off-line by two blinded observers in the control and stress conditions. The results showed that 1) the sensitivity of dobutamine, dipyridamole and pacing stress tests was 57, 57 and 36%, respectively; 2) in animals with positive tests, the mean percent change of wall thickening in left ventricular ischemic segments was larger in the pacing (-19 +/- 11%) and dipyridamole (-18 +/- 16%) tests as compared to dobutamine (-9 +/- 6%) (P = 0.05), but a similar mean reduction of wall thickening was observed when this variable was normalized to a control left ventricular segment (area related to the left anterior descending artery) (pacing: -16 +/- 7%; dipyridamole: -25 +/- 16%; dobutamine: -26 +/- 10%; not significant), and 3) a significant correlation was observed between magnitude of coronary stenosis and left ventricular segmental dysfunction induced by ischemia in dogs submitted to positive stress tests. We conclude that the dobutamine and dipyridamole stress tests showed identical sensitivities for the detection of myocardial ischemia in this one-vessel disease animal model with a wide range of left circumflex artery stenosis. The pacing stress test was less sensitive, but the difference was not statistically significant. The magnitude of segmental left ventricular dysfunction induced by ischemia was similar in all stress tests evaluated.

Ventricular function in Chagas' heart disease.

Invasive and noninvasive methods used to evaluate ventricular function in Chagas's disease are reviewed. The traditional indices of overall ventricular performance reflect the interaction of preload, contractility, afterload and heart rate. Therefore, they are unable to distinguish changes in contractility from modifications of loading conditions. The role of ventricular function as a predictor of mortality in chronic Chagas' heart disease is discussed. Ventricular function abnormalities in patients with indeterminate and digestive forms of Chagas' disease are especially emphasized. Finally, the evidence of early impairment of diastolic performance in digestive forms of Chagas' disease are especially emphasized. Finally, the evidence of early impairment of diastolic performance in patients with Chagas' disease is presented.

[Hemodynamic study of peripartum cardiopathy following compensation of heart failure]. / Estudo hemodinâmico na cardiopatia periparto após compensação da insuficiência cardíaca.

PURPOSE: To assess hemodynamic characteristics of patients with peripartum cardiomyopathy under standardized conditions of clinical compensation of heart failure, and more than 3 months after the end of the gravidic period. PATIENTS AND METHODS: Fourteen patients with peripartum cardiomyopathy underwent left and right cardiac catheterization, under rest condition. Cardiac output was measured by the Fick method, left ventricular ejection fraction determined by contrast ventriculography, and the coronary circulation was studied angiographically. RESULTS: The hemodynamic pattern observed was variable, with 28% of the cases showing low right and left ventricular filling pressures, normal LV ejection fraction, and normal or even elevated cardiac output, with low pulmonary and systemic vascular resistance. CONCLUSION: Although the mechanisms responsible for such peculiar hemodynamic characteristics, have not been elucidated, it is likely that they are associated with more benign prognosis, as compared to other patients with peripartum cardiomyopathy, who show the low-output failure commonly seen in cases of dilated cardiomyopathy.

Head-to-head comparison of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia in an animal model of coronary artery stenosis

To compare the sensitivity of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia we produced a physiologically significant stenosis in the left circumflex artery of 14 open-chest dogs (range: 50 to 89 percent reduction in luminal diameter). In each study, dobutamine (5 to 40 æg kg-1 min-1 in 3-min stages) and pacing (20 bpm increments, each 2 min, up to 260 bpm) were performed randomly, and then followed by dipyridamole (up to 0.84 mg/kg over 10 min). The positivity of stress echocardiography tests was quantitatively determined by a significant (P<0.05) reduction of or failure to increase absolute and percent systolic wall thickening in the stenotic artery supplied wall, as compared to the opposite wall (areas related to the left anterior descending artery). Systolic and diastolic frozen images were analyzed off-line by two blinded observers in the control and stress conditions. The results showed that 1) the sensitivity of dobutamine, dipyridamole and pacing stress tests was 57, 57 and 36 percent, respectively; 2) in animals with positive tests, the mean percent change of wall thickening in left ventricular ischemic segments was larger in the pacing (-19 Ý 11 percent) and dipyridamole (-18 Ý 16 percent) tests as compared to dobutamine (-9 Ý 6 percent) (P = 0.05), but a similar mean reduction of wall thickening was observed when this variable was normalized to a control left ventricular segment (area related to the left anterior descending artery) (pacing: -16 Ý 7 percent; dipyridamole: -25 Ý 16 percent; dobutamine: -26 Ý 10 percent; not significant), and 3) a significant correlation was observed between magnitude of coronary stenosis and left ventricular segmental dysfunction induced by ischemia in dogs submitted to positive stress tests. We conclude that the dobutamine and dipyridamole stress tests showed identical sensitivities for the detection of myocardial ischemia in this one-vessel disease animal model with a wide range of left circumflex artery stenosis. The pacing stress test was less sensitive, but the difference was not statistically significant. The magnitude of segmental left ventricular dysfunction induced by ischemia was similar in all stress tests evaluated