Transient ischemia does not limit subsequent ischemic regional dysfunction in humans: a transesophageal echocardiographic study during minimally invasive coronary artery bypass surgery.

OBJECTIVES: This study sought to assess the effects of sequential coronary artery occlusion during minimally invasive coronary artery bypass graft surgery (CABG) on hemodynamic variables and left ventricular systolic function by means of transesophageal echocardiography (TEE). BACKGROUND: Clinical and experimental studies suggest a protective effect of ischemic preconditioning in patients with acute coronary syndromes. However, the effect of repetitive myocardial ischemia on myocardial mechanical function in humans is not completely understood. METHODS: Seventeen patients with left anterior descending coronary artery (LAD) stenosis > or =70% and normal rest left ventricular systolic function referred for minimally invasive CABG underwent intraoperative TEE for assessment of regional left ventricular wall motion and measurement of hemodynamic variables at baseline (baseline 1), during a 5-min coronary occlusion (occlusion 1), after a 5-min reperfusion period (baseline 2) and a during a second coronary occlusion during bypass anastomosis (occlusion 2). RESULTS: Left ventricular wall motion score (LVWMS) increased significantly from baseline (16.0) to occlusion 1 (21.4+/-3.1 [mean +/- SD], p < 0.05) and occlusion 2 (21.8+/-3.1, p < 0.05). No difference in LVWMS was noted between occlusions 1 and 2. Pulmonary artery systolic pressure increased significantly from baseline (25+/-6 mm Hg) to occlusion 1 (32+/-7 mm Hg, p < 0.05) and occlusion 2 (33+/-6 mm Hg, p < 0.05). Pulmonary artery diastolic pressure also increased significantly from baseline (12+/-4 mm Hg) to occlusion 1 (16+/-4 mm Hg, p < 0.05) and occlusion 2 (16+/-4 mm Hg, p < 0.05). No significant differences in pulmonary artery pressures were noted between occlusions 1 and 2. CONCLUSIONS: Ischemic dysfunction was precipitated by the 5-min LAD occlusion, as shown by the increase in LVWMS and pulmonary artery pressure. However, a 5-min coronary occlusion and the resulting ischemia do not alter regional left ventricular systolic function during subsequent ischemia in humans.

Amniotic fluid interleukin-1 in spontaneous labor at term.

The regulatory signals responsible for the increased biosynthesis of prostaglandins during parturition have not been established. Interleukin-1 (IL-1) is capable of stimulating prostaglandin production by intrauterine tissues and is an inflammation mediator. It has been postulated as a signal for the onset of labor in the setting of intrauterine infection. A study was designed to determine if spontaneous labor at term was associated with changes in IL-1 activity in amniotic fluid. Such fluid was retrieved from 41 women in labor and from 39 women who were not in labor at term. Immunodetectable IL-1 beta was present in 22 of the 41 women in labor but in only 8 of the 39 women without labor. IL-1-like bioactivity was not different between the two groups at a dilution of 1:4, but at dilutions of 1:12, 1:36 and 1:108, amniotic fluid from women in labor had significantly higher bioactivity than that from women not in labor. A significant correlation was found between the bioassay and immunoassay results. Our data show that inhibitors of IL-1 bioactivity are present in amniotic fluid and suggest that in a subset of laboring women at term, an inflammatory reaction may play a role in triggering the onset of parturition.