Acute myocardial dysfunction and recovery: A common occurrence after coronary bypass surgery

Abstract

To evaluate whether acute myocardial dysfunction was common in the early postoperative period, serial hemodynamic measurements and radionuclide evaluation of ventricular function were performed before and after operation in 24 patients undergoing elective coronary bypass surgery. All patients had uncomplicated surgery, and no patient sustained an intraoperative infarction. In 96% of patients, significant depression in right and left ventricular ejection fraction was seen postoperatively, reaching a nadir at 262 +/- 116 min after coronary bypass. Left ventricular ejection fraction was 58 +/- 12% preoperatively and 37 +/- 10% at trough. Right ventricular function displayed a similar pattern. These findings were also associated with depressed cardiac and left ventricular stroke work index despite maintenance of adequate ventricular filling pressures and mean arterial pressure. The depression in ventricular function was partially reversible within 8 to 10 h after surgery. Left ventricular ejection fraction had increased to 55 +/- 13% at 426 +/- 77 min after coronary bypass and showed complete recovery within 48 h. Left ventricular end-systolic and end-diastolic volume index increased significantly postoperatively, but recovery in left ventricular ejection fraction was mostly due to decreases in end-systolic volume index (50 +/- 22 ml at trough and 32 +/- 16 ml at recovery). Depressed myocardial function was independent of bypass time, number of grafts placed, preoperative medications or core temperatures postoperatively. Postoperative therapy with pressors or inotropic agents delayed but did not prevent the occurrence of postoperative ventricular dysfunction. Despite improvements in operative techniques and methods of myocardial protection, postoperative left ventricular dysfunction continues to be common in patients undergoing cardiopulmonary bypass surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Medical and Cellular Implications of Stunning, Hibernation, and Preconditioning

“…Despite the most modern cardioplegic techniques, some postsurgical stunning is common. [86][87][88][89] Many patients require inotropic support and pressors for hours to days after surgery, which eventually can be weaned as the stunning abates.…”

Corrected right ventricular end-diastolic volume and initial distribution volume of glucose correlate with cardiac output after cardiac surgery

“…Appropriate adjustment of cardiac preload is essential to maintain cardiac output (CO) 2 especially in patients following cardiac surgery, but the evaluation is not easily 3 performed, since either impairment of cardiac function [1][2][3] or internal bleeding may 4 occur following cardiac surgery. Cardiac preload is traditionally assessed by its filling 5 pressures, but edema or focal ischemia of myocardium after cardiac surgery may affect 6 ventricular compliance, leading to poor correlations between these pressures and the 7 end-diastolic volume, which makes these preload variables unreliable [4] .…”

“…The presence of arrhythmias also makes RVEDV difficult to assess cardiac preload, 1 since RVEDV is calculated from stroke volume (SV) divided by RVEF and SV is not 2 constant under arrhythmia condition. However, it has not been studied adequately 3 whether RVEDV or cRVEDV indicated cardiac preload in the presence of arrhythmias 4 following cardiac surgery.…”

“…However, the mean ΔCI in this group was only 0.02 ± 0.51 L/min/m 2 . 3 Biancofiore et al reported that a small change in CO (ΔCO) should be excluded to 4 assess the accuracy of CO measurement [25] . According to a report of Critcheley et al a 5 minimal ΔCO is required 0.5 -1.0 L/min for this purpose [26] .…”

High dose propofol enhances red cell antioxidant capacity during CPB in humans

“…The origins of this problem are multifactorial and include ischemia-reperfusion injury (IRI). [1][2][3][4][5][6][7] Interest has focused on the potential of anesthetics to protect the heart and lung against IRI, due to their ability to modify oxidant mediated cell injury, s,9 Recently, the intravenous anesthetic, 2,6-diisopropylphenol, propofol, has been shown to have antioxidant properties, l~ Experimental evidence suggests propofol may protect the myocardium and lung against peroxide and peroxynitrite) 2,1s However, a recent study did not provide clinical evidence of protection with propofol anesthesia used for cardiac procedures. I4 The dose of propofol administered (50 to 100 lag.kg-l.min -1) was limited by the concern that propofol may produce hypotension secondary to cardiac depression and vasodilatation.…”