Perioperative Acute Myocardial Infarction Research Articles

Evaluation of Serum Creatine Kinase and Lactate Dehydrogenase in Experimental Myocardial Infarction, Atriotomies, and Thoracotomies

Myocardial infarction causes elevation of the serum myocardial-associated isoenzyme of creatine kinase (CK-MB) and a serum isoenzyme of lactate dehydrogenase (LDH 1). Since atrial myocardium has as much CK-MB as ventricular myocardium, surgical manipulation of the atrium could cause elevation of serum CK-MB in the postoperative period. The distribution of LDH isoenzymes is different between atrial and ventricular myocardium. Hence, surgical procedures on the atrium could, theoretically, cause different changes in serum LDH isoenzymes than those seen after acute myocardial infarction. This study was conducted to ascertain whether surgical manipulation of the atrium could cause changes in these two serum enzyme systems that might be confused with those seen after acute myocardial infarction. Right thoracotomies were performed on 20 dogs. Each dog then was assigned randomly to one of four groups: thoracotomy (control), placement of atrial pursestring sutures, atriotomy, or acute perioperative myocardial infarction. Serum total and isoenzyme distributions of CK and LDH were measured for 48 hours in all animals. The results suggest that significant elevations of serum CK-MB occurred even after small atriotomies. Confirmation of a ventricular myocardial origin of postoperative serum CK-MB bands was obtained by analysis of serum LDH isoenzymes in that the ratio of LDH 1 to LDH 2 and the absolute value of serum LDH 1 became elevated only after acute perioperative myocardial infarction and not after atriotomy.

Perioperative Acute Myocardial Infarction (PMI) in Coronary Bypass Surgery: Is it Related to Pre-Operative Ischaemia?

Perioperative Acute Myocardial Infarction (PMI) in Coronary Bypass Surgery: Is it Related to Pre-Operative Ischaemia?

The value of radionuclide angiography as a predictor of perioperative myocardial infarction in patients undergoing abdominal aortic aneurysm resection.

To define the group of patients at high risk for myocardial infarction (MI) and death associated with abdominal aortic aneurysm repair, resting gated blood pool studies were obtained on 50 such aneurysm patients preoperatively. The results indicated that three groups could be distinguished among these patients by cardiac ejection fraction. Group I (n = 25) had preoperative ejection fractions ranging from 56% to 85%. None of the patients in group I suffered an acute perioperative MI. Group II (n = 20) comprised patients with ejection fractions ranging from 36% to 55%. There was a 20% incidence of MI in group II but no cardiac deaths. Group III included five patients with ejection fractions ranging from 27% to 35%. There was an 80% incidence of perioperative MI in these patients, with one cardiac death and one cardiac arrest. All perioperative MIs occurred within the first 48 hours after surgery. In addition there was a 50% incidence of perioperative MI among all those patients who were 80 years of age or older. These results indicate guidelines for the management of patients undergoing abdominal aortic aneurysm repair based on their preoperative ejection fraction. The data further suggest that the noninvasive gated blood pool method of determining ejection fraction may serve a more broadly useful function in helping to determine which of those patients about to undergo major surgical procedures are at high risk for perioperative MI.

The value of radionuclide angiography as a predictor of perioperative myocardial infarction in patients undergoing abdominal aortic aneurysm resection

To define the group of patients at high risk for myocardial infarction (MI) and death associated with abdominal aortic aneurysm repair, resting gated blood pool studies were obtained on 50 such aneurysm patients preoperatively. The results indicated that three groups could be distinguished among these patients by cardiac ejection fraction. Group I (n = 25) had preoperative ejection fractions ranging from 56% to 85%. None of the patients in group I suffered an acute perioperative MI. Group II (n = 20) comprised patients with ejection fractions ranging from 36% to 55%. There was a 20% incidence of MI in group II but no cardiac deaths. Group III included five patients with ejection fractions ranging from 27% to 35%. There was an 80% incidence of perioperative MI in these patients, with one cardiac death and one cardiac arrest. All perioperative MIs occurred within the first 48 hours after surgery. In addition there was a 50% incidence of perioperative MI among all those patients who were 80 years of age or older. These results indicate guidelines for the management of patients undergoing abdominal aortic aneurysm repair based on their preoperative ejection fraction. The data further suggest that the noninvasive gated blood pool method of determining ejection fraction may serve a more broadly useful function in helping to determine which of those patients about to undergo major surgical procedures are at high risk for perioperative MI.

The definition of myocardial infarction during aortocoronary bypass surgery

In a study of 392 aortocoronary bypass (CABG) patients, we found 16 patients with a postoperative new Q wave, 29 patients with new intraventricular conduction disturbance, 17 patients with cardiogenic shock, and 14 patients with excessive CK-MB activity. Those criteria were considered as diagnostic of perioperative acute myocardial infarction (AMI). Listing the 392 patients in a Venn diagram: five patients had three positive criteria, eight had two, 43 had one, and 336 had none. Ventricular arrhythmia, supraventricular arrhythmia, or ST-T changes occurred in decreasing frequency in patients with a decreasing number of positive criteria. Five patients died postoperatively and in four a postmortem examination was available. Diagnostic criteria partly predicted autopsy findings. We conclude that the diagnostic criteria of perioperative myocardial infarction have a low diagnostic performance.

Perioperative Myocardial Infarction Associated with Coronary Artery Bypass Graft Surgery: Improved Sensitivity in the Diagnosis Within 6 Hours after Operation with 99mTc-Glucoheptonate Myocardial Imaging and Myocardial-Specific Isoenzymes

The present study was performed to evaluate scintigraphic imaging with technetium 99m-labeled glucoheptonate and serum enzyme levels of creatine phosphokinase isoenzyme (MB-CPK) in the early diagnosis of perioperative acute myocardial infarction associated with saphenous vein bypass graft operations. Myocardial imaging was done in 27 patients (50% of whom were considered high-risk) before operation and again 5 hours after operation. Four of these patients (15%) had both electrocardiographic and serum MB-CPK evidence of acute myocardial infarction, and all 4 had developed positive postoperative scintigrams. Four other patients had only elevated serum MB-CPK, and scintigrams became positive after operation in 3 of them. In addition, serum MB-CPK 6 hours after operation was 83 ± 21 mIU/ml (mean ± standard error of the mean) in patients with positive post-operative scans compared with 24 ± 5 mIU/ml in those patients with negative postoperative scintigrams ( p < 0.001). Myocardial imaging with 99mTc-glucoheptonate in the perioperative period is rapid, safe, and atraumatic. Furthermore, our results suggest that it is a sensitive method for the early diagnosis of perioperative acute myocardial infarction, and, when imaging is combined with serum MB-CPK isoenzyme analysis, the reliability of the diagnosis of acute myocardial infarction is enhanced even further. Only 1 of the patients who showed perioperative myocardial damage had acute hemodynamic compromise or obvious impairment of recovery in the immediate postoperative period, and the 30-day mortality of the total group was 4% (1 of 27).

Coronary artery bypass surgery for left main coronary artery disease

The course of 146 consecutive patients with significant occlusive disease of the left main coronary artery who underwent coronary artery bypass surgery during a 4 year period is reviewed. Preoperatively, 11 patients were in New York Heart Association functional class II, 57 in class III and 78 in class IV. Seventy patients had progressive angina and 12 unstable angina. There were two operative deaths (surgical mortality rate 1.4 percent). Seven patients (4.8 percent) had a perioperative acute myocardial infarction. Complete follow-up has been achieved in the surgical survivors over an average period of 18.1 months; 77 percent of the surviving patients are completely asymptomatic and 19 percent are in functional class II. Four patients (2.8 percent) had a nonfatal late postoperative myocardial infarction and five (3.5 percent) died during the late postoperative period (3.3 percent annual mortality rate during a 2 to 47 month follow-up period). Postoperative cardiac catheterization studies performed in 35 patients an average of 12.1 months postoperatively revealed 78 percent of 80 grafts and patency of at least 1 graft in 93 percent of patients. Results of 42 (89 percent) of 47 near maximal treadmill stress tests were abnormal preoperatively compared with results of 14 (26 percent) of 54 postoperatively; in 74 percent of patients having both a preoperative and postoperative stress test, abnormal preoperative test results converted to normal after surgery. This study suggests that direct myocardial revascularization may offer an effective means of improving both the quality and duration of life in a patient with significant occlusive disease of the left main coronary artery.