Association between early postoperative coagulation activation and peri-operative myocardial ischaemia in patients undergoing vascular surgery.

We investigated the association of peri-operative myocardial ischaemia with activation of coagulation and endogenous fibrinolysis in patients undergoing vascular surgery. In 50 patients, continuous Holter monitoring was performed to assess peri-operative myocardial ischaemia and 12-lead electrocardiography was recorded preoperatively and 72 h postoperatively to assess myocardial infarction. Serial blood samples were drawn peri-operatively to determine the concentrations of fibrin monomers (for activation of coagulation), D-dimer (for endogenous fibrinolysis) and cardiac troponin T and I. Patients with myocardial ischaemia showed higher concentrations of fibrin monomers at 48 h, and higher concentrations of d-dimer preoperatively and at 24 and 48 h postoperatively. In patients with peri-operative myocardial ischaemia, strong positive correlations were observed between fibrin monomer and D-dimer concentrations at 15 min and 4 h postoperatively, and cardiac troponins at 15 min and at 4, 24, 48 and 72 h postoperatively. Early postoperative activation of coagulation and fibrinolysis is associated with peri-operative myocardial cell damage among patients who are at risk for, or have a history of, coronary artery disease plus peri-operative myocardial ischaemia.

Postoperative 12-lead ECG predicts peri-operative myocardial ischaemia associated with myocardial cell damage.

Peri-operative myocardial ischaemia is the single most important risk factor for an adverse cardiac outcome after non-cardiac surgery. The present study examines whether intermittent 12-lead ECG recordings can be used as an early warning tool to identify patients suffering from peri-operative myocardial ischaemia and subsequent myocardial cell damage. Fifty-five vascular surgery patients at risk for or with a history of coronary artery disease were monitored for peri-operative myocardial ischaemia using intermittent 12-lead ECG recordings taken pre-operatively and at 15 min, 20 h, 48 h, 72 h and 84 h postoperatively. The effectiveness of the 12-lead ECG was gauged by examining concordance with continuous 3-channel Holter monitoring and capturing peri-operative myocardial ischaemia by serial analyses of creatine kinase myocardial band isoenzyme and cardiac troponin T and I. The incidence of peri-operative myocardial ischaemia detected by 12-lead ECG was 44% and was identifiable in most patients (88%) 15 min after surgery. The incidence of peri-operative myocardial ischaemia detected by continuous monitoring was 53%, with the most severe episodes occurring intra-operatively and during emergence from anaesthesia. The concordance of the 12-lead method with continuous monitoring was 72%. The concordance of creatine kinase myocardial band isoenzyme activity with the 12-lead method was 71% and with Holter monitoring 57%. The concordance of mass concentration of creatine kinase myocardial band with 12-lead ECG recordings was 75%, and the corresponding value for Holter monitoring was 68%. The concordance of cardiac troponin T and I levels with the 12-lead method was 85% and 87%, respectively, and concordance with Holter monitoring was 72% and 66%, respectively. The postoperative 12-lead ECG identified peri-operative myocardial ischaemia associated with subsequent myocardial cell damage in most patients undergoing vascular surgery.

Effect of atenolol on mortality and cardiovascular morbidity after noncardiac surgery. Multicenter Study of Perioperative Ischemia Research Group.

BACKGROUND: Perioperative myocardial ischemia is the single most important potentially reversible risk factor for mortality and cardiovascular complications after noncardiac surgery. Although more than 1 million patients have such complications annually, there is no effective preventive therapy. METHODS: We performed a randomized, double-blind, placebo-controlled trial to compare the effect of atenolol with that of a placebo on overall survival and cardiovascular morbidity in patients with or at risk for coronary artery disease who were undergoing noncardiac surgery. Atenolol was given intravenously before and immediately after surgery and orally thereafter for the duration of hospitalization. Patients were followed over the subsequent two years. RESULTS: A total of 200 patients were enrolled. Ninety-nine were assigned to the atenolol group, and 101 to the placebo group. One hundred ninety-four patients survived to be discharged from the hospital, and 192 of these were followed for two years. Overall mortality after discharge from the hospital was significantly lower among the atenolol-treated patients than among those who were given placebo over the six months following hospital discharge (0 vs. 8 percent, P<0.001), over the first year (3 percent vs. 14 percent, P=0.005), and over two years (10 percent vs. 21 percent, P=0.019). The principal effect was a reduction in deaths from cardiac causes during the first six to eight months. Combined cardiovascular outcomes were similarly reduced among the atenolol-treated patients; event-free survival throughout the two-year study period was 68 percent in the placebo group and 83 percent in the atenolol group (P=0.008). CONCLUSIONS: In patients who have or are at risk for coronary artery disease who must undergo noncardiac surgery, treatment with atenolol during hospitalization can reduce mortality and the incidence of cardiovascular complications for as long as two years after surgery.

Comparison of cardiac morbidity rates between aortic and infrainguinal operations: two-year follow-up. Study of Perioperative Ischemia Research Group.

PURPOSE: We have previously prospectively compared the differences in perioperative cardiac ischemic events in 140 patients undergoing major abdominal (n = 53) versus infrainguinal (n = 87) vascular operations. This study was designed to extend these observations by determining the 2-year cardiac prognosis of patients at high risk undergoing abdominal aortic versus infrainguinal vascular operations. METHODS: Data included historical, clinical, and laboratory data collected during the in-hospital period, and at 6 months, 1 year, and 2 years after surgery. This information was collected independently of the usual clinical care visits. Data were analyzed with Cox's proportional hazards model. RESULTS: There were 11 in-hospital deaths overall (five [9%] aortic; six [7%]) infrainguinal). 628 days (median 726 days). Fifteen patients (12%) had fatal myocardial infarctions, two (4%) of which occurred in patients who underwent aortic procedures and 13 (16%) of which occurred in patients who underwent infrainguinal operations. Nonfatal myocardial infarctions befell one (2%) patient undergoing aortic surgery and four (5%) patients undergoing infrainguinal surgery. One (2%) patient undergoing aortic surgery and three (4%) patients undergoing infrainguinal surgery were admitted to the hospital with unstable angina during the follow-up period. In all, adverse cardiac outcomes occurred in 20 of 81 (25%) patients who had infrainguinal procedures compared with four of 48 (8%) patients who had aortic operations (p = 0.04). Multivariate analysis showed that a history of diabetes (p = 0.001) and definite coronary artery disease (p = 0.01) are independently associated with adverse outcomes after both types of peripheral vascular operations. CONCLUSIONS: The incidence of long-term adverse cardiac outcomes in patients at high risk undergoing infrainguinal operations is substantially greater than in those undergoing aortic operations, mostly because of a greater prevalence of diabetes, and definite coronary artery disease in the former group.

Comparison of cardiac morbidity between aortic and infrainguinal operations. Study of Perioperative Ischemia (SPI) Research Group.

We prospectively compared the differences in perioperative cardiac ischemic events in 140 patients undergoing major abdominal (n = 53) versus infrainguinal (n = 87) vascular operations. Preoperative dipyridamole thallium cardiac scintigraphy was performed in a subset of 38 of these patients, with treating physicians blinded to the test results. Myocardial ischemia was measured during operation with use of continuous 12-lead electrocardiography (ECG) and transesophageal echocardiography. Continuous two-lead ambulatory ECG (Holter monitoring) was performed before, during, and after operation for 4 days. Outcome events were cardiac death, nonfatal myocardial infarction, unstable angina, ventricular tachycardia, and congestive heart failure. Results of the study indicated that most demographic variables, such as age, hypertension, cigarette smoking, serum cholesterol, were comparable between patients having aortic or infrainguinal arterial operations. However, in the infrainguinal group more patients had diabetes, second vascular operations, angina pectoris, heart failure, dysrhythmias, and used digitalis. Abnormalities in preoperative Holter monitoring, ECGs, and thallium scan abnormalities were equivalent between groups. During operation, whereas Holter and ECG abnormalities were comparable, more patients undergoing aortic procedures suffered ischemia as determined by transesophageal echocardiography (26% vs 10%, p = 0.019). After operation there were 21 (24%) outcome events in patients having infrainguinal bypasses compared with 15 (28%) patients having aortic procedures (p = NS). Ischemia by Holter monitoring (n = 133) occurred after operation in 46 (57%) patients having infrainguinal operations compared with 16 (31%) patients having aortic reconstructions (p = 0.005). Because preoperative cardiac disease and adverse cardiac outcomes occurred with similar or even greater frequency in both groups of patients, we conclude that the risk for postoperative cardiac ischemic events in lower extremity vascular operations is at least as great as for aortic operations.

Dipyridamole thallium-201 scintigraphy as a preoperative screening test. A reexamination of its predictive potential. Study of Perioperative Ischemia Research Group.

BACKGROUND: We examined the value of dipyridamole thallium-201 (201Tl) scintigraphy as a preoperative screening test for perioperative myocardial ischemia and infarction. METHODS AND RESULTS: We prospectively studied 60 patients undergoing elective vascular surgery. We performed 201Tl scintigraphy preoperatively and blinded all treating physicians to the results. Historical, clinical, laboratory, and physiological data were gathered throughout hospitalization. Myocardial ischemia was assessed during the intraoperative period using continuous 12-lead electrocardiography (ECG) and transesophageal echocardiography (TEE) and during the postoperative period using continuous two-lead ambulatory ECG. Adverse cardiac outcomes (cardiac death, myocardial infarction, unstable angina, severe ischemia, or congestive heart failure) were assessed daily throughout hospitalization. Twenty-two patients (37%) had defects that improved or reversed on delayed scintigrams (redistribution defects), 18 (30%) had persistent defects, and 20 (33%) had no defects on 201Tl scintigraphy. There was no association between redistribution defects and adverse cardiac outcomes: 54% (seven of 13) of adverse outcomes occurred in patients without redistribution defects, and the risk of an adverse outcome was not significantly increased in patients with redistribution defects (relative risk 1.5, 95% confidence interval 0.6-3.9, p = 0.43). Consistent with these findings, there was also no association between redistribution defects and perioperative ischemia: 54% (19 of all 35) of perioperative ECG and TEE ischemic episodes and 58% (14 of 24) of severe ischemic episodes occurred in patients without redistribution defects. The sensitivity of 201Tl scintigraphy for perioperative ischemia and adverse outcomes ranged from 40% to 54%, specificity from 65% to 71%, positive predictive value from 27% to 47% and negative predictive value from 61% to 82%. CONCLUSIONS: These results differ from those of previous studies and suggest that the routine use of 201Tl scintigraphy for preoperative screening of patients undergoing vascular surgery may not be warranted.