Vladimir Yakirevich

Tumor necrosis factor-alpha is released from the isolated heart undergoing ischemia and reperfusion

OBJECTIVES The purpose of this study was to examine whether tumor necrosis factor-alpha (TNF-alpha) is released directly from the ischemic myocardium undergoing reperfusion. BACKGROUND Tumor necrosis factor-alpha is a protein hormone produced by systemic leukocytes (primarily by activated macrophages). It has been implicated as a systemic mediator in the development of septic shock and other pathologic conditions. Serum TNF-alpha has also been detected in a variety of cardiac disease states and after myocardial ischemia-reperfusion injury. METHODS Nine isolated rat hearts undergoing 30 min of perfusion, followed by warm cardioplegic arrest, 1 h of global ischemia and 30 min of reperfusion, were investigated using the modified Langendorff model. RESULTS Significant amounts of TNF-alpha (752 +/- 212 pmol/ml) were detected in the effluent during the first minute of reperfusion. Tumor necrosis factor-alpha levels correlated with postischemic deterioration in peak systolic pressures (r = 0.7882, p = 0.012), dP/dt max (r = 0.6795, p = 0.044), time-pressure integral (r = 0.7661, p = 0.0016) and postischemic creatine kinase levels (r = 0.8367, p = 0.005). The deterioration in coronary flow, however, was inversely correlated with TNF-alpha levels (r = -0.7581, p = 0.018). CONCLUSIONS To our knowledge, this study is the first to suggest that the isolated rat myocardium synthesizes and releases TNF-alpha in response to ischemia and reperfusion, which directly correlates with the postischemic deterioration in myocardial mechanical performance and the amount of cellular necrosis.

High-Dose Isosorbide Dinitrate for Myocardial Revascularization With Composite Arterial Grafts

BACKGROUND Composite arterial grafting for myocardial revascularization is a surgical technique in which free arterial conduits are proximally attached to an in situ internal mammary artery. METHODS Composite arterial grafting was performed in 78 patients with internal mammary artery (n = 24), inferior epigastric artery (n = 21), or radial artery (n = 33) connected to the internal mammary artery. Overall, 254 distal anastomoses were performed (average number, 3.3 per patient), 225 of which were arterial. All patients were treated postoperatively with high-dose isosorbide dinitrate (4 to 20 mg/h for 24 hours). RESULTS The in-hospital mortality rate was 2.6% (2 patients). Early recatheterization studies performed 3 weeks (range, 1 to 20 weeks) after operation in 30 patients demonstrated patency rates of 100%, 93%, and 100% for the composite internal mammary artery, inferior epigastric artery, and radial artery groups, respectively. In addition, two inferior epigastric artery conduits had major intraluminal constriction. At a mean follow-up of 20 months (range, 1 to 42 months) all patients are alive, and all but 2 in the inferior epigastric group (97%) are angina free. CONCLUSIONS This surgical technique can be safely used. On the basis of our experience, the right internal mammary artery and the radial artery are the most suitable conduits for this procedure. High-dose nitrates given perioperatively prevent spasm and ensure early patency rates.

Captopril in Cardioplegia and Reperfusion: Protective Effects on the Ischemic Heart

BACKGROUND Previous studies have shown that long-term treatment with the angiotensin-converting enzyme inhibitor captopril attenuates left ventricular dilatation and improves survival after extensive myocardial infarction. However, there is only sparse evidence of the immediate effects of the drug on hearts undergoing global ischemia and reperfusion. The purpose of this study was to investigate the direct effect of captopril, given in cardioplegia or after ischemia, on the functional recovery of the reperfused myocardium. METHODS Isolated rat hearts undergoing warm cardioplegic arrest followed by 1 hour of global ischemia and 30 minutes of reperfusion were studied using the modified Langendorff model. RESULTS After ischemia, hearts receiving captopril (360 mumol/L) either in the cardioplegic solution (n = 9) or during reperfusion (n = 9) developed higher pressure (p < 0.001), greater first derivative of the rise in left ventricular pressure (p < 0.01 and p < 0.001, respectively), greater first derivative of the fall in left ventricular pressure (p < 0.001 and p < 0.002), higher pressure-time integral (p < 0.001), greater coronary flow (p < 0.001), and higher oxygen consumption values (p < 0.001 and p < 0.003) compared with the control group (n = 9). Hearts receiving captopril both in the cardioplegia and during reperfusion (n = 9) had the best recovery of all three groups and lower levels of creatine kinase (47.8 +/- 5.9 U/L versus 73.3 +/- 5.6 U/L; p < 0.01) compared with the control group. CONCLUSIONS Captopril given in cardioplegia and in reperfusion has a favorable, protective, and additive effect on the recovery of isolated rat hearts undergoing global ischemia and reperfusion; hemodynamic performance improves, coronary flow and oxygen consumption increase, and myocardial damage decreases.

Impact of early exercise radionuclide cineangiography on long-term prognosis after CABG

BACKGROUND The immediate benefits of coronary artery bypass grafting might be only transient. This prospective study examined the capability of exercise radionuclide cineangiography done shortly after coronary artery bypass grafting to predict outcome and long-term prognosis. METHODS Results of exercise radionuclide cineangiography at 5.5 +/- 0.7 months (range, 4 to 8 months) postoperatively were correlated with mortality, major surgical and nonsurgical cardiac events, and cardiac event-free survival in 100 consecutive patients who underwent coronary artery bypass grafting. Stepwise logistic regression analysis was used to evaluate the incremental value of radionuclide cineangiography beyond the commonly used variables. RESULTS Left ventricular ejection fraction at rest was normal (> or = 0.45) in 72 patients and increased on exercise in 58. The exercise radionuclide variables that correlated with future cardiac events were change and fractional change in heart rate, ST segment changes, anginal pain and congestive heart symptoms during exercise, rest ejection fraction, and change and fractional changes in ejection fraction. Predictors of event-free survival were exercise heart rate, rest ejection fraction, and change and fractional change in ejection fraction during exercise. Logistic regression analysis revealed that change in ejection fraction was an independent predictor of cardiac death and surgical interventions, whereas resting ejection fraction was a predictor of nonsurgical cardiac events. CONCLUSIONS Postoperative exercise radionuclide cineangiography carried out soon after coronary artery bypass grafting had definite independent prognostic value and should be performed routinely to help decide treatment protocol.

Intermittent poppet dislodgment in a Braunwald-Cutter prosthesis: noninvasive diagnosis and successful surgical treatment.

A 65 year old patient had his mitral and aortic valves replaced with two Braunwald-Cutter prostheses in 1973. Seven years later, he presented with intermittent aortic insufficiency demonstrated by echocardiography, fluoroscopy and angiography. At emergency surgery, the occluders (poppets) of both prostheses were found within the left ventricular cavity. The valves were excised and replaced with Björk-Shiley prostheses and the patient recovered. Aortic occluder escape is rare and usually fatal. Mitral occluder escape of the Braunwald-Cutter prosthesis has not been described previously.

Expanded use of Internal Mammary Artery Graft for Myocardial Revascularization

To improve the early and late benefits of coronary artery bypass grafting, use of internal mammary artery grafts was expanded. The first 60 patients to receive two mammary artery-coronary artery anastomoses and supplemental saphenous vein grafts are reviewed. Altogether 210 grafts (3.5/patient) were performed, including 54 mammary artery grafts in situ, six of them as free grafts. In 12 patients the right internal mammary artery was placed through the transverse sinus to revascularize the circumflex artery, and the left mammary artery was placed to the left anterior descending artery. In the remaining 48 patients both internal mammary arteries were used to revascularize the left anterior descending and the right coronary artery. There were no perioperative deaths and no sternal infections. Postoperative complications included re-exploration for bleeding and diaphragmatic dysfunction. Late follow-up was complete. Of 60 patients observed for 1/2 to 4 years, 57 were asymptomatic. Exercise stress tests were performed in 58 cases and were normal in 56.

Surgical revascularization following failed percutaneous transluminal coronary angioplasty.

Percutaneous transluminal coronary angioplasty (PTCA) was performed on 200 patients and failed in 36, 12 of whom underwent myocardial revascularization within 3 hours after the angioplasty attempt. Elective operations were performed without complications in the other 24 cases. The 12 emergency operations were necessitated by major complications during or after PTCA, viz, coronary occlusion (6 patients) coronary dissection (2) and failed catheter passage or dilation with severe myocardial ischemia (4). Three of these 12 patients had signs of acute myocardial infarction preoperatively, and new infarction appeared postoperatively in two cases. All eight patients with ST-segment elevation preoperatively had raised levels of myocardial enzymes postoperatively, and two of them had new Q-waves. Three of the 12 patients required inotropic drugs following revascularization. There was one postoperative death. When complications arise in PTCA, emergency operation should be undertaken. When PTCA fails, but without complications, surgery can be electively performed.