The effects of a flexible ventricular restraint device on left ventricular (LV) dilatation and hypertrophy after transmural infarction are examined in an ovine model. Left ventricular remodeling and dilatation occurs after extensive myocardial infarction. A flexible ventricular restraint made from a nitinol mesh was evaluated in adult female sheep (n=14). Cardiac magnetic resonance imaging scans and hemodynamic measurements were completed before and 6 weeks after anterior myocardial infarction. Treatment animals (n=7) received passive ventricular restraint concurrently with LV infarction; the others (n=7) served as controls. Increases in LV end-diastolic volume index were significantly less in the restraint group than in controls (0.20+/-0.41 vs 0.83+/-0.50 ml/kg, p<0.03). End-systolic volumes increased less in treatment animals (0.43+/-0.28 vs 0.90+/-0.38 ml/kg, p<0.03). Control hearts showed an increase in LV mass after infraction, whereas LV mass decreased in restrained hearts (0.14+/-0.19 vs -0.25+/-0.36 g/kg, p<0.03). Hemodynamic studies showed similar changes after infarction for the control and the device group. Gross and microscopic examination showed no device-induced epicardial injury. A flexible ventricular restraint device attenuated remodeling after acute myocardial infarction in sheep.
Postoperative inflammatory response is common in heart surgery patients, but less is known about variation in the baseline inflammatory state. This study characterizes the preoperative inflammatory profile in a group of high- and low-risk patients (n = 32; male 16, female 16; mean age, 70.3 +/- 1.8) and relates this to postoperative events. Interleukin-6 (IL-6), tumor necrosis factor (TNF)-alpha, TNF receptors (R1 and R2), and high-sensitivity C-reactive protein were measured before surgery and 4 hours after arrival in the intensive care unit. Considerable variability existed in all preoperative inflammatory mediators before surgery. Patients with an elevated baseline IL-6 level, (IL-6 >10 pg/mL) were older (73.5 +/- 2.2 vs. 67.9 +/- 2.6 years), had a lower ejection fraction (34 +/- 3.8% vs. 44 +/- 2.9%), a higher predicted risk score (10.3 +/- 1.2 vs. 5.9 +/- 1.1), and a higher baseline high-sensitivity C-reactive protein (65 +/- 10 vs. 24 +/- 6 mg/L), p < 0.05 for all. These patients had high morbidity and mortality rates after surgery. In addition, patients judged to be at high risk on clinical criteria were found to have consistent elevations in the baseline inflammatory state. All patients had a surge in inflammatory mediators after surgery, but those who started at a higher baseline reached a higher postoperative level than the others (IL-6 2023 +/- 561 vs. 361 +/- 47 pg/mL, p < 0.05). Many heart surgery patients, especially higher-risk patients, have a significant inflammatory state before surgery. These patients are at risk for high morbidity and mortality rates after surgery.
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