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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A total of 105 patients underwent combined coronary artery and valvular operations. Sixty-six had combined coronary artery bypass grafting (CABG) and aortic valve replacement (AV), 28 had CABG and mitral valve operations (MV), and 11 patients had CABG and double or triple valve operations (DTV). An average of 3.0 bypasses was done, range one to seven. These patients were compared to a similar group of patients who underwent valve replacement(s) only, without CABG. Bypass time was increased for the combined groups, as was ischemic cross-clamp time. Early mortality was 3.0% AV, 3.5% MV, and 9.1% DTV in the combined groups and 1% in the valve only groups. The higher mortality for the combined groups was almost entirely due to the 23% mortality in women over 70 years of age. Perioperative myocardial infarction (MI) was higher in the combined groups (5% MI, 9% probable MI versus 2.9% MI, 4.1% probable MI). All survivors were in improved clinical condition and free of angina. Mortality and improvement were unrelated to perioperative infarction. The small increase in risk compared to the significant improvement from the combined approach has led to the following principles: coronary arteriography on all adult patients requiring valvular operations; bypass of all significant coronary lesions; restoration of valvular function and hemodynamics; and myocardial preservation with cold cardioplegia during a single period of cross clamping, topical cold, and systemic hypothermia.
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PMID:Results of combined valvular and myocardial revascularization operations. 660 Aug 1

This study was aimed to evaluate the hypothesis that the left ventricular myocardium has different resistance to ischemic stress, thus, perioperative myocardial infarction occurs in the myocardium with poor resistance to ischemia. Patients who died of acute low output syndrome after coronary artery bypass graft under potassium induced cardioplegia associated with topical and systemic hypothermia were studied by histopathology of the left ventricular muscle taken at the time of autopsy. Distal regions of the myocardium to various degree of stenosis of the coronary artery were selected for examination. Ischemic myocardial damage that appears most likely the events in the perioperative period was observed sporadically in the normal myocardial architecture independent of the degree of stenosis of the coronary arteries. Thus, this result suggests that the regional myocardium has different resistance to global ischemia, and it may be responsible to perioperative myocardial infarction.
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PMID:[Problem in myocardial protection in coronary artery bypass surgery; regional difference of myocardial tolerance to global ischemia]. 660 4

Hypothermic potassium cardioplegia has become the most popular technique for myocardial preservation during coronary revascularization. However, an older technique continues to yield comparable results with some potential advantages. Myocardial preservation was achieved with systemic hypothermia to 28 degrees C, pericardial cooling, elective ventricular fibrillation, maintenance of systemic perfusion pressure between 80 and 100 mm Hg, routine left ventricular venting, and local vessel isolation during distal anastomoses without aortic occlusion. Proximal anastomoses were performed prior to atrial cannulation and cardiopulmonary bypass. Nonemergency isolated bypass grafting was performed in 500 consecutive patients, of whom 51% had had a prior myocardial infarction, 24% had unstable angina, and 21% had left main coronary stenosis. Primary grafting was performed in 483 patients and reoperations in 17. The mean number of grafts per patient was 3.8. Perioperative myocardial infarction occurred in 1.8%. Hospital mortality was 0.4%. Late follow-up was obtained for all survivors at a mean postoperative interval of 17.8 months. All survivors were asymptomatic or improved over their preoperative status. The 3 year actuarial survival rate was 95.8%, equivalent to that for the matched general population. Of 287 male patients under age 65, 68.4% were working preoperatively and 69.5% postoperatively. This technique provides results comparable to bypass grafting with cardioplegia and may be useful when aortic occlusion or administration of cardioplegic solutions is not desirable.
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PMID:Noncardioplegic myocardial preservation for coronary revascularization. 661 56

The effect of moderate whole-body hypothermia on blood flow to acutely ischemic and nonischemic myocardium and on the relationship between blood flow and necrosis after 5 hours of left anterior descending (LAD) coronary artery occlusion was investigated in 20 dogs. Blood flow to ischemic myocardium was not significantly increased or decreased by hypothermia. However, much less myocardial necrosis (shown by nitro blue tetrazolium staining) was observed in the hypothermia-treated animals. Therefore, this protective effect of hypothermia is not a result of improved blood flow to the ischemic region, but is more likely due to decreased metabolic requirements. Nearby noninfarcted myocardium had slightly higher blood flow than homologous tissue in the corresponding controls under both normothermic and hypothermic conditions. This tissue, which must compensate for the loss of contractility in the ischemic region, appears to maintain its ability to respond to increased demand for blood flow even during moderate hypothermia. Blood pressure and cardiac output data indicate that hypothermia did not interact with myocardial infarction to produce or exacerbate cardiogenic shock. Consequently, whole-body hypothermia may prove to be a safe and effective emergency pretreatment which may significantly decrease the amount of necrotic myocardium when initiated prior to emergency coronary artery bypass surgery.
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PMID:Effect of whole-body hypothermia on myocardial blood flow and infarct salvage during coronary artery occlusion in dogs. 672 May 26

The effects of the addition of 20 mg sodium allopurinate to a litre of ionic cardioplegic solution were studied. The experimental model was the working isolated perfused rat heart in oxygenated Krebs-Henseleit solution. The cardiac outputs were compared after 1 hour of ischaemia with three different methods of myocardial protection; group I: protection by hypothermia at 4 degrees C, group II: protection by ionic cardioplegic solution A, group III: by ionic cardioplegic solution B (with 20 mg Allopurinol). The results were expressed in percentage of the preischemic cardiac output. The best results were obtained in group III, especially after 15 minutes recovery (80.7 +/- 4.5 p. 100 at 15 minutes, 90.6 +/- 3.1 p. 100 at 30 minutes., 88.3 +/- 4.6 p. 100 at 1 hour). The results in group II were significantly better than in group I after 10 minutes recovery. Myocardial protection bu ionic cardioplegia associated with hypothermia at 4 degrees C gives a better post ischaemic recovery than hypothermia alone. When allopurinol is added to the cardioplegic solution, the protection is increased. These effects are similar to the haemodynamic effects of allopurinol on ischaemic myocardium together with the possible limitation of experimental myocardial infarction with regression of the oedema that has been observed with this drug.
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PMID:[Myocardial protection during ischemic cardiac arrest. Hemodynamic study of the effects of allopurinol in a cardioplegic solution]. 677 65

Four hundred eighty adult patients undergoing cardiac operations had systemic and topical hypothermic anoxic arrest supplemented with potassium chloride pharmacological cardioplegia in a prospective randomiz ed study. Group 1 (217 patients) had continuous aortic cross-clamping and one single anoxic arrest period during the cardiac portion of the operation, which resulted in a transmural myocardial infarction rate of 8.3%, myocardial "injury" incidence of 12.4%, 4.6% cardiac-related deaths, 11.5% and 24.8% severe and malignant ventricular arrhythmias, 21.7% rate of severe vasopressor usage, a mean group serum glutamic oxaloacetic transaminase (SGOT) of 140 +/- 39 IU, and a mean group lactic dehydrogenase (LDH) of 636 +/- 78.2 IU. Group 2 (263 patients) had intermittent aortic cross-clamping with multiple reperfusion intervals, which resulted in a significantly lower incidence of transmural myocardial infarction at 1.9% (p < 0.01), rate of myocardial injury at 5.66% (p < 0.02), number of cardiac deaths at 0.76% (p < 0.02), 8.7% and 16.0% severe and malignant ventricular arrhythmias (p < 0.01), severe vasopressor utilization rate of 14.3% (p < 0.05), mean group SGOT at 72.0 +/- 3.1 IU (p < 0.01), and mean group LDH at 471.0 +/- 12.3 IU (p < 0.05) than Group 1. These results do not support the contention that intermittent aortic cross-clamping in conjunction with hypothermia and pharmacological cardioplegia leads to increased clinical cardiac damage compared with continuous aortic cross-clamping. The converse is implied, in that the anoxic heart may benefit from the physiological effects of briefly reperfused oxygenated blood.
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PMID:Is reperfusion injury from multiple aortic cross-clamping a current myth of cardiac surgery? 696 84

Postoperative graft patency and thirteen perioperative variables were evaluated as potential risk factors for perioperative myocardial infarction (MI) in 102 consecutive patients undergoing coronary artery bypass grafting. Also, the incidence of perioperative MI and the amount of CK-MB released in the postoperative period were compared in three groups of patients selected according to the myocardial preservation technique employed: (1) topical hypothermia with and (2) without aortic cross-clamping and (3) cardioplegia. A perioperative MI as detected by electrocardiogram, enzymes, and myocardial scintigraphy with technetium 99 developed in 15 patients. Most important predictors of perioperative MI were found to be (1) left main and triple-vessel coronary artery disease, (2) a left ventricular end-diastolic pressure greater than or equal to 15 mm Hg, (3) a decreased ejection fraction (p < 0.05), and (4) cardiopulmonary bypass time > 120 minutes (p < 0.01). The incidence of perioperative MI was 50% in patients with three or more risk factors and 7% in those with less than three risk factors (p < 0.001). Graft patency was similar in patients with or without perioperative MI. Differing myocardial preservation techniques did not influence CK-MB release or the incidence of perioperative MI. Thus, the severity of ischemic heart disease and the length of the cardiopulmonary bypass time were important predictors of perioperative MI while graft patency and myocardial preservation technique did not appear to be related to its incidence in this study.
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PMID:Predictors of perioperative myocardial infarction in coronary artery operation. 697 16

The incidence of coronary artery reoperations averaged 2.7% from 1967 through 1979. In a mean interval of 51 months between operations, three-vessel disease increased from 24% to 63%, and 31% of these 500 consecutive patients lost previously normal left ventricular function. Three angiographic indication groups were identified: (1) progressive coronary atherosclerosis, 247 (51%); (2) graft failure, 147 (29%); and (3) a combination of progressive coronary atherosclerosis and graft failure, 96 (19%). Angina recurred earlier in patient with graft failure, mean 17 months compared with a mean of 37 months for the other groups. Twenty (4%) operative deaths occurred. The series is divided into 387 patients operated upon under normothermic anoxic arrest and 113 with systemic hypothermia and cold cardioplegia. In the cardioplegia group, perioperative myocardial infarction was 2.7% in comparison with 7.8% for patients with anoxic arrest (p = 0.055). The number of grafts per patient increased from 1.0 to 1.9 and blood usage decreased from 11 units to 2.7 units. After a mean follow-up of 42 months, angina was relieved or improved in 86%. Recatheterization of 104 patients after a mean interval of 19 months showed a 79% vein graft patency rate and a 97% mammary artery graft patency rate. Grafting performed for graft failure (47) yielded an 85% patency rate. Actuarial 5 year survival was 87.4% for those with progressive atherosclerosis, 89.4% for patients with graft failure, and 91.5% for the combined indication group. Clinical improvement, graft patency, and long-term survival are nearly equal among the indication groups. Palliation derived from these reoperations approaches that achieved after primary revascularization.
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PMID:Late clinical and arteriographic results in 500 coronary artery reoperations. 697 75

The influence of three methods of myocardial preservation used during coronary artery bypass grafting on operative mortality and perioperative myocardial infarction was evaluated in seven institutions participating in the Coronary Artery Surgery Study (CASS). Both operative mortality and perioperative infarctions were comparable with either normothermic and topical hypothermic myocardial preservation. The addition of potassium cardioplegia to hypothermia lowered both operative mortality and perioperative myocardial infarction (p less than 0.01 and p less than 0.001, respectively). Stepwise multivariate discriminant analysis revealed that the high-risk clinical and angiographic variables were the most important determinants of operative mortality, followed by surgical priority and the use of potassium cardioplegia. However, none of the clinical, angiographic and surgical variables other than the use of potassium cardioplegia influenced the incidence of perioperative myocardial infarction.
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PMID:Preservation of the myocardium during coronary artery bypass grafting. 697 28

Hypothermic cardioplegia (HCP) is a method commonly used for myocardial preservation at the time of aortic cross-clamping during coronary artery bypass grafting (CABG). This study assessed the frequency and significance of transient bundle branch block (BBB) in 50 patients undergoing CABG using HCP compared to 61 controls. All patients had normal QRS complexes on preoperative ECG. CLinical, hemodynamic, and operative data were similar in both groups. Seventeen (34%) of the HCP group and four (6%) of the controls developed postoperative BBB (p less than 0.001). These changes were transient in all but three patients in the HCP group. None of the HCP patients with transient BBB had evidence of perioperative myocardial infarction. Clinical and operative parameters did not provide prediction of development of transient BBB. This study demonstrates that transient BBB in the immediate post-CABG period occurs commonly with the use of HCP and does not indicate myocardial necrosis.
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PMID:Transient bundle branch block following use of hypothermic cardioplegia in coronary artery bypass surgery: high incidence without perioperative myocardial infarction. 697 51


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