Non-Q wave perioperative myocardial infarction: assessment of the incidence and severity of regional dysfunction with quantitative two-dimensional echocardiography

Effect of Aortic Cross-Clamp Time on Myocardial Infarction after Coronary Bypass Surgery

Univariate and multivariate statistical analyses were applied to 1200 consecutive patients undergoing first-time myocardial revascularization. Forty-three patients (3.6%) developed evidence of myocardial infarction as judged by serial electrocardiograms and release of enzymes. Out of 23 preoperative and intraoperative potential risk factors for perioperative myocardial infarction, multivariate regression analysis revealed that duration of aortic cross-clamping was a powerful continuous variable risk factor. The relative risk increased twofold at 44 minutes compared to 17 minutes, approached three times the risk at 53 minutes, and reached more than six times the risk after 84 minutes of aortic cross-clamping. Two other independent predictors for perioperative myocardial infarction were identified: the presence of preoperative arterial hypertension and significant (> 75%) left main coronary artery stenosis. Left ventricular impairment, gender, age, severity of angina, and the number of distal anastomoses were not identified as risk factors for perioperative myocardial infarction. Our data indicate that the incidence of perioperative myocardial infarction may be reduced by consistent efforts to minimize aortic cross-clamp time without compromising the adequacy of myocardial revascularization.

Cardiac Troponin I Concentrations during On-Pump Coronary Artery Surgery

Perioperative myocardial infarction remains a frequent complication after coronary artery bypass grafting, and is associated with a poor prognosis. This retrospective study compared cardiac troponin I concentrations after on-pump bypass grafting in 2 groups of patients: 100 operated on using a single-clamp technique to perform anastomoses, and 80 operated on using a double-clamp technique. Postoperative cardiac troponin I levels were not significantly different between groups. It was concluded that the double-clamp technique did not reduce the incidence of myocardial infarction after elective on-pump coronary artery bypass grafting, and use of a single clamp is safe with no adverse effect on postoperative outcome.

Detection of perioperative myocardial infarction with ischemia-modified albumin

We assessed the perioperative pattern of serum ischemia-modified albumin and its role as a myocardial ischemia indicator for early detection of perioperative myocardial infarction in patients undergoing off-pump coronary artery bypass grafting. Venous blood samples were collected from 63 consecutive patients before the operation, immediately after the operation, and at 3, 6, 12, and 24 h postoperatively. Serum ischemia-modified albumin levels were analyzed using an albumin cobalt binding test. The patients were divided into 2 groups retrospectively, according to the occurrence of perioperative myocardial infarction. The serum ischemia-modified albumin levels were compared between groups. The levels peaked immediately after the operation, followed by a gradual regression, but remained elevated during the first 24 h in all patients. The occurrence of perioperative myocardial infarction was identified in 10 patients who had significantly higher ischemia-modified albumin levels at 3 h postoperatively and slower regression rates. Perioperative serum ischemia-modified albumin levels might be helpful in predicting perioperative myocardial infarction.

Troponin I as a diagnostic marker of a perioperative myocardial infarction in the orthopedic population

STUDY OBJECTIVE

To assess the utility of troponin I, the only molecular marker of myocardial injury not expressed in regenerating muscle, in diagnosing perioperative myocardial infarction (MI) in the setting of orthopedic surgery where false elevations in creatine kinase MB isoenzymes (CKMB) are known to occur.

DESIGN

Prospective study.

SETTING

University-affiliated hospital.

PATIENTS

85 patients with risk factors for coronary artery disease (CAD) who were scheduled for orthopedic surgery, including total knee arthroplasty, 34; total hip arthroplasty, 36; posterior spine fusion, 7; and other orthopedic operations, 8.

INTERVENTIONS

Patients were observed in the postanesthesia care unit for at least 24 hours where they had an electrocardiogram (ECG) performed, and blood drawn to rule out MI.

MEASUREMENTS

Blood samples for measurement of creatine kinase MB isoenzymes (CKMB) and troponin I were drawn at 8-hour intervals for up to 24 hours.

MAIN RESULTS

Five (5/85) patients had elevated levels of both CKMB and troponin I postoperatively. New ECG abnormalities were present in all but one patient who had an old anterolateral MI. Troponin I peaked within 16 hours except in one patient where it continued to increase. That female patient developed cardiogenic pulmonary edema. All the others did well clinically. Six patients (6/85) had a positive CKMB index, and a negative troponin I level. None had ECG changes, except for one in whom subsequent cardiac catheterization showed insignificant CAD. They all did well clinically. All patients with an elevated troponin I level had a positive CKMB index.

CONCLUSIONS

Troponin I is as sensitive a marker of MI as CKMB in the orthopedic population, but it has a higher specificity in the perioperative setting. Troponin I can be helpful in properly identifying the source of CKMB elevation postoperatively when this elevation is questionable.

Increased mortality after coronary artery bypass graft surgery is associated with increased levels of postoperative creatine kinase-myocardial band isoenzyme release: results from the GUARDIAN trial

OBJECTIVES

We sought to determine if elevated cardiac serum biomarkers after coronary artery bypass graft surgery (CABG) are associated with increased medium-term mortality and to identify patients that may benefit from better postoperative myocardial protection.

BACKGROUND

The relationship between the magnitude of cardiac serum protein elevation and subsequent mortality after CABG is not well defined, partly because of the lack of large, prospectively studied patient cohorts in whom postoperative elevations of cardiac serum markers have been correlated to medium- and long-term mortality.

METHODS

The GUARD during Ischemia Against Necrosis (GUARDIAN) study enrolled 2,918 patients assigned to the entry category of CABG and considered as high risk for myocardial necrosis. Creatine kinase-myocardial band (CK-MB) isoenzyme measurements were obtained at baseline and at 8, 12, 16 and 24 h after CABG.

RESULTS

The unadjusted six-month mortality rates were 3.4%, 5.8%, 7.8% and 20.2% for patients with a postoperative peak CK-MB ratio (peak CK-MB value/upper limits of normal [ULN] for laboratory test) of < 5, > or = 5 to <10, > or =10 to < 20 and > or =20 ULN, respectively (p < 0.0001). The relationship remained statistically significant after adjustment for ejection fraction, congestive heart failure, cerebrovascular disease, peripheral vascular disease, cardiac arrhythmias and the method of cardioplegia delivery. Receiver operating characteristic curve analysis revealed an area under the curve of 0.648 (p < 0.001); the optimal cut-point to predict six-month mortality ranged from 5 to 10 ULN.

CONCLUSIONS

Progressive elevation of the CK-MB ratio in clinically high-risk patients is associated with significant elevations of medium-term mortality after CABG. Strategies to afford myocardial protection both during CABG and in the postoperative phase may serve to improve the clinical outcome.

Using postoperative cardiac Troponin-I (cTi) levels to detect myocardial ischaemia in patients undergoing vascular surgery

BACKGROUND

Cardiac complications occur commonly in vascular surgery patients. Diagnosis of cardiac complications is difficult because of the inaccuracies associated with traditional cardiac enzyme measurements. CTi, a highly sensitive and specific marker of myocardial injury, may be able to detect cardiac complications with greater ease and accuracy.

METHODS

The study prospectively examined 100 consecutive patients who underwent major vascular surgery between 6/7/98 and 31/12/98 at the Royal Brisbane Hospital. Daily measurements of cTi, creatine kinase (CK), creatine kinase MB (CKMB), CKMB index, renal function and haemoglobin were taken for three postoperative days. One postoperative electrocardiograph (ECG) was taken. An extensive cardiac history was taken. Intraoperative and postoperative events were recorded.

FINDINGS

There were 100 patients. 18 patients (18%) had a cTi elevation. On the basis of classical diagnostic criteria, 15 patients (15%) suffered one or more cardiac complication (either myocardial infarction, congestive cardiac failure, unstable angina or atrial fibrillation). One patient (1%) who had a cTi elevation died. CTi elevation occurred in five patients (5%) who were not diagnosed with cardiac complications based on traditional criteria. Despite not meeting specific diagnostic criteria for cardiac complications, all patients showed signs and symptoms that could be attributed to myocardial ischaemia. Every patient who developed congestive cardiac failure or atrial fibrillation had a cTi elevation. A Chi-square analysis revealed a significant association between cTi elevation and postoperative cardiac complications. Four variables contributed small but significant amounts of unique variance to the prediction of peak cTi on linear regression analysis. These were peak CKMB index, postoperative congestive cardiac failure, postoperative chest pain and postoperative cardiac complications.

CONCLUSIONS

Routine cTi monitoring of postoperative vascular patients would be an effective and inexpensive way to detect patients with cardiac complications. The relationship between postoperative cTi elevation and significant coronary artery disease remains to be shown.

Pericardial cardiac troponin I release after coronary artery bypass grafting

Pericardial fluid can reflect the composition of cardiac interstitium in myocardial ischemia. This study investigated the hypothesis that pericardial cardiac troponin I (CTnI) measurements could be a more accurate marker of perioperative myocardial infarction (MI) than serum CTnI after coronary artery bypass grafting (CABG). Postoperative arterial and pericardial blood samples were taken in 102 subjects undergoing elective CABG allocated to one of three groups according to the 12-lead electrocardiogram (ECG) abnormalities observed during the first postoperative 24 h: Group 1 = normal ECG; Group 2 = nonspecific ECG abnormalities; and Group 3 = perioperative Q-wave MI. Peak pericardial CTnI concentrations were much higher than peak serum concentrations in all subjects and significantly greater in Group 3 than in Groups 1 and 2 (1,318 +/- 1,810 ng/mL vs 367 +/- 339 ng/mL and 558 +/- 608 ng/mL, respectively; P < 0.01). However, no significant difference between groups occurred at any time for pericardial/serum CTnI ratios, indicating that time courses of CTnI were not different in pericardial fluid and serum. A significant correlation was found between serum and pericardial CTnI concentrations (R = 0.70, P < 0.001). Pericardial CTnI was not more accurate than serum CTnI in predicting Q-wave MI as shown by the low value of the area under the receiver-operator characteristic curve (= 0.71). Peak and early pericardial CTnI were also not accurate in predicting an increase of serum CTnI greater than a cutoff value of 19 ng/mL. Thus, pericardial CTnI measurements were less useful than serum CTnI measurements in the diagnosis of perioperative MI after CABG.

IMPLICATIONS

Although cardiac troponin I concentrations were much higher in pericardial fluid than in serum and significantly increased in subjects who experienced perioperative Q-wave myocardial infarction, pericardial cardiac troponin I measurements were of less value than serum cardiac troponin I measurements for the diagnosis of perioperative myocardial infarction after coronary artery bypass grafting and cannot be recommended in routine clinical practice.

Cardiac troponin I and Q-wave perioperative myocardial infarction after coronary artery bypass surgery

OBJECTIVE

To monitor cardiac troponin I (cTnI), a newly developed biochemical index for cardiac damage, in patients during and after coronary artery bypass surgery (CABS) to determine whether the measurement of the serum levels of this marker could be of value in formulating an early diagnosis of Q-wave perioperative myocardial infarction (PMI).

DESIGN

Prospective study with sequential measurements of biological markers in a selected surgical patient group.

SETTING

University research laboratory and general university hospital (Cardiac Surgery Unit and Anesthesiology and Reanimation Unit).

PATIENTS

Forty-two patients undergoing elective CABS without concomitant valvular replacement.

INTERVENTIONS

There were no interventions required for this study. However, patients entered into the study had CABS, sequential arterial blood samples, ECG recordings, and echocardiograms performed.

MEASUREMENTS AND MAIN RESULTS

Pre-, intra-, and postoperative (up to 48 hrs) measurements of cardiac troponin I, MB-CK, and total creatine kinase, as well as serial electrocardiograms and echocardiograms. Perioperative infarction was assessed as the development of new persistent regional wall motion abnormalities in echocardiography together with electrocardiographic alterations and MB-CK increases. Eight patients had Q-wave PMI. All PMI patients had elevated peak cTnI values (all >9.2 ng/mL), whereas the 34 nonPMI patients had peak values <9.0 ng/mL; therefore, sensitivity and specificity (with a 9.0 ng/mL cut-off value) are 100%. MB-CK measurement peak values did not demonstrate such a high specificity and sensitivity.

CONCLUSIONS

Because of its high specificity and sensitivity, serial measurements of cTnI provide a rapid and accurate method for confirming or excluding the diagnosis of perioperative myocardial injury. cTnI evaluation can therefore be used both as an independent prognostic marker for patients undergoing cardiac surgery and as a powerful tool for detecting smaller PMIs often missed with standard PMI diagnostic criteria.

Minimally invasive coronary surgery: surgical considerations and assessment of cardiac troponin I

OBJECTIVE

Minimally invasive coronary artery bypass grafting (MICABG) using internal thoracic artery (ITA) without median sternotomy and cardiopulmonary bypass (CPB) become a viable option for the management of proximal left anterior descending artery (LAD) disease. Recent studies have demonstrated that cardiac troponine I (cTnI), a new highly specific diagnostic marker of cardiomyocyte damage, is a reliable marker of cardiac ischemia during heart operations under CPB.

METHODS

Between February 1996 and April 1997, 14 patients (10 males, 4 females aged 41-68) underwent MICABG with single-vessel bypass grafting for LAD stenosis (n = 9) or occlusion (n = 5). Video-assisted surgery with left anterior mini-thoracotomy was performed in ten patients and vertical parasternal thoracotomy in the other four. cTnI was measured before LAD occlusion (T0), during anastomosis (T1) and 10 min (T2), 6 h (T3), 24 h (T4), 48 h (T5), 72 h (T6) after coronary reperfusion. Assay methods used a specific enzyme-linked immunosorbent autoanalyzer (Stratus) in peripheral venous blood. Control coronary angiography was performed in all patients.

RESULTS

There were no operative complications, no reoperations for bleeding. cTnI concentrations were expressed in ng/ml +/- SD. Mean cTnI level was <3.85+/-1 ng/ml (range 0-32.8). Values were: T0 = 0, T1 = 0.5+/-0.1, T2 = 1.15+/-0.2, T3 = 2.16+/-0.6, T4 = 1.5+/-0.3, T5 = 0.6+/-0.02, T6 = 0.4+/-0.01. Angiography showed patent grafts in 12 patients. A 'no flow situation' was demonstrated in a cardiac symptom-free patient, with reestablishment of flow on repeat angiogram at 6 months. In the other case, early ITA graft occlusion in a patient with two-vessel disease was correlated with a higher cTnI concentration (17.8 ng/ml). Percutaneous angioplasty was performed on the right coronary artery, complicated with dissection and cardiac failure. This patient died 3 months after the MICABG despite ventricular assist device.

CONCLUSION

cTnI did not increase during and after coronary artery occlusion and local immobilization of the heart. It can be used to evaluate postoperative myocardial damage on the beating heart using MICABG.

Differentiation between transmural perioperative myocardial infarction and subendocardial injury after coronary artery bypass grafting using biochemical tests, elaborated by cluster and discriminant analysis

The aim of this study is to differentiate between transmural perioperative myocardial infarction (T-PMI) and subendocardial perioperative myocardial injury (S-PMI) as a complication of coronary artery bypass grafting (CABG). Seventy-three patients undergoing CABG were followed post operatively by measuring troponin T, CK-MB isoenzyme mass concentration (CK-MB mass), creatine kinase MB isoenzyme activity (CK-MB activity), creatine kinase (CK), alpha hydroxybutyrate dehydrogenase (HBD), and aspartate aminotransferase (AST) at five sampling times. Lacking a proper definition of the gold standard for the diagnosis of perioperative myocardial infarction, a statistical procedure was used. Supported by the cluster analysis method of Ward, patients were assigned to a patient group with a perioperative myocardial infarction (PMI) or a patient group without a PMI (non-PMI) as a confirmation of interpretation of the biochemical results. Using the results of electrocardiogram (ECG) and echocardiography, the PMI patient group was split into a T-PMI patient group and a S-PMI patient group. With discriminant analysis, two canonic discriminant functions were drawn up to differentiate between patients suffering from a T-PMI or S-PMI and non-PMI patients.

Safety of beating heart anastomosis during video-assisted coronary surgery attested by cardiac troponin I

Our objective was to evaluate the safety of coronary anastomosis on the beating heart by measuring the release of cardiac troponin I during minimally invasive coronary artery bypass grafting (MICABG). Cardiac troponin I (cTnI) is a reliable marker of cardiac ischemia during heart operations under cardiopulmonary bypass (CPB). Ten patients (8 males and 2 females, aged 41-63) underwent MICABG with single vessel bypass grafting for left anterior descending coronary artery (LAD) stenosis (n = 7) or occlusion (n = 3). Video-assisted surgery with left anterior minithoracotomy was performed in all patients. Serial venous blood samples were collected for measurement of cTnI before LAD occlusion (T0), during anastomosis (T1) and 10 min (T2), 6 h (T3), 24 h (T4), 48 h (T5), and 72 h (T6) after coronary reperfusion. The assay method used a specific enzyme-linked immunosorbent Stratus autoanalyzer. Control coronary angiography was performed in all patients. There were no operative complications or reoperations for bleeding. The cTnI concentrations were expressed in ng/ml +/- SD. The mean cTnI level was less than 3.05 +/- 0.2 ng/ml (range 0-32.8). Values were T0 = 0, T1 = 0.4 +/- 0.03, T2 = 1.15 +/- 0.2, T3 = 2.16 +/- 0.6, T4 = 1.5 +/- 0.3, T5 = 0.6 +/- 0.02, and T6 = 0.4 +/- 0.01. Angiography showed patent grafts in 9 patients. In one case, early internal thoracic artery (ITA) graft occlusion in a patient with 2 vessel disease was correlated with a higher cTnI concentration (17.8 ng/ml). Percutaneous angioplasty was performed on the right coronary artery, complicated with dissection and cardiac failure. This patient died 3 months after the MICABG despite support from a ventricular assist device. In conclusion, collateral circulation developed in the setting of chronic coronary occlusion may be efficient for myocardial preservation during short periods such as coronary anastomosis. cTnI immunoassay confirmed the safety of coronary anastomosis on the beating heart during minimally invasive coronary operations.

Relationship of regional wall motion abnormalities detected by biplane transesophageal echocardiography and electrocardiographic changes in patients undergoing coronary artery bypass graft surgery

BACKGROUND

It has been demonstrated that new regional wall motion abnormalities (RWMAs) are infrequently associated with electrocardiographic (ECG) ischemic changes during coronary artery bypass graft (CABG) surgery. The evaluation of apical or basal areas by biplane transesophageal echocardiography (TEE) may clarify the relationship between RWMA and ECG changes.

METHODS

Biplane TEE and ECG (leads II and V5) were continuously monitored in a total of 98 patients undergoing CABG surgery to determine the incidence and characteristics of RWMAs and to relate these findings to ECG changes.

RESULTS

Twenty-four new RWMAs were detected in 21 (21%) patients. Incidences of new RWMAs in each view were found to be as follows: 12 (50%) in short-axis view (SAV); 5 (21%) in long-axis view (LAV); and 7 (29%) in both views. Ten of the 24 new RWMA episodes (42%) corresponded to ECG ischemic changes. These new ECG changes were significantly more common when the new RWMAs appeared on both views (86%) as compared with the LAV alone (0%) (p < 0.01) or with SAV alone (33%). Moreover, in patients with a greater number of abnormal segments (> 3), new RWMAs were significantly (p < 0.05) associated with ECG changes.

CONCLUSION

Biplane TEE provides additional information about spatial distribution of new RWMAs. This study was the first to demonstrate that a clear relationship between TEE and ECG ischemia exists. When these new RWMAs exhibited a large spatial distribution, the frequency of ECG ischemic changes increased.

Current incidence and determinants of perioperative myocardial infarction in coronary artery surgery

Increasingly, patients undergoing coronary artery bypass grafting (CABG) are elders, have had previous CABG, and have poor left ventricular function. To evaluate determinants of perioperative myocardial infarction (PMI) after isolated CABG, 499 consecutive patients were reviewed. Definite PMI (total peak creatine kinase [CK] > 700 U/L, creatine kinase MB [CK-MB] > 30 ng/ml, and new pathologic electrocardiographic Q waves) occurred in 25 patients (5.0%) and probable PMI (total peak CK > 700 U/L, CK-MB > 30 ng/ml, and a new wall-motion abnormality) occurred in 10 (2.0%) patients. According to multivariate logistic regression analysis, independent risk factors for definite or probable PMI (adds ratios; 95% confidence intervals) were emergency surgery (3.1; 1.1 to 8.4; p = 0.003), aortic cross-clamp time > 100 minutes (4.2; 1.6 to 11.2; p = 0.004), myocardial infarction in the preceding week (2.6; 1.0 to 6.4; p = 0.04), and previous revascularization (2.4; 1.1 to 5.2; p = 0.02). In conclusion, both preoperative and intraoperative factors influence the risk of PMI after CABG. Despite changes in the profile of patients undergoing CABG, the incidence of PMI in this tertiary center is comparable with that found in earlier series, probably because of improvements in surgical techniques and postoperative care.

Diagnosis of perioperative myocardial infarction with measurement of cardiac troponin I

BACKGROUND

Perioperative myocardial infarction is the most common cause of morbidity and mortality in patients who have had noncardiac surgery, but its diagnosis can be difficult. The present study was designed to determine whether the measurement of serum levels of cardiac troponin I, a highly sensitive and specific marker for cardiac injury, would help establish the diagnosis of myocardial infarction.

METHODS

We obtained preoperative measurements of MB creatine kinase, total creatine kinase, and cardiac troponin I, in addition to base-line electrocardiograms and two-dimensional echocardiograms, in 96 patients undergoing vascular surgery and 12 undergoing spinal surgery. Blood samples were obtained every 6 hours for at least the first 36 hours after surgery, and electrocardiograms were obtained daily; a second echocardiogram was obtained approximately three days after surgery. The appearance of a new abnormality in segmental-wall motion on the postoperative echocardiogram (that is, an abnormality that had not been seen on the preoperative echocardiogram) was considered to be indicative of perioperative infarction.

RESULTS

Eight patients who underwent vascular surgery had new abnormalities in segmental-wall motion and received a diagnosis of perioperative infarction. All eight had elevations of cardiac troponin I, and six had elevations of MB creatine kinase. Of the 100 patients without perioperative infarction detected by echocardiography, 19 had elevations of MB creatine kinase, and 1 had a slight elevation of cardiac troponin I.

CONCLUSIONS

The measurement of cardiac troponin I is a sensitive and specific method for the diagnosis of perioperative myocardial infarction. It avoids the high incidence of false diagnoses associated with the use of MB creatine kinase as a diagnostic marker.

Echocardiography in coronary artery disease

Echocardiography has a major role in the evaluation of patients with CAD. To obtain the maximal amount of information using this technique, certain basic principles relating to regional myocardial mechanics during ischemia and flow-function relations are required. In addition, a detailed knowledge of cardiac anatomy and the three-dimensional orientation of the heart within the chest cavity is required to access meaningful information from two-dimensional planes. Furthermore, skill is also required in acquiring data in proper imaging planes and in separating true (actual pathology) from the false (artifacts, etc.). Echocardiography is not a "mature" technology. It is still developing and it is sometimes difficult to keep up with the advances. However, keeping abreast of these developments is essential to fully exploit the advantages of this technique. In addition, knowledge of the ever-changing aspects of CAD is required in order to correctly interpret visual information in context of a particular patient. Finally, more clinical studies are needed to further define the role of echocardiographic techniques in patients with CAD.

Myocardial infarction determined by technetium-99m pyrophosphate single-photon tomography complicating elective coronary artery bypass grafting for angina pectoris

The incidence of acute myocardial infarction (AMI) complicating coronary artery bypass grafting (CABG) has previously been based on concordance of electrocardiographic, enzymatic and scintigraphic criteria. Technetium-99m pyrophosphate (Tc-PPi) single-photon emission computed tomography now enables detection of AMI with high sensitivity and specificity. Using this technique, perioperative AMI was detected in 12 of 58 patients (21%) undergoing successful elective CABG for stable angina pectoris. Stepwise multivariate logistic regression analysis was performed to compare the predictive value of preoperative (New York Heart Association class, left ventricular ejection fraction and use of beta blockers) and intraoperative (number of grafts constructed, use of internal mammary anastomoses, use of sequential saphenous vein grafts, smallest grafted distal vessel lumen caliber and aortic cross-clamp time) variables. Preoperative New York Association class (p = 0.04) and smallest grafted distal vessel lumen caliber (p = 0.03) were significant multivariate predictors of perioperative AMI. Only 1 perioperative patient with AMI (and 1 pyrophosphate-negative patient) developed new Q waves. Serum creatine kinase-MB was higher in patients with AMI by repeated measures analysis of variance (p = 0.0003). Five AMIs occurred in myocardial segments revascularized using sequential saphenous vein grafts, and 7 in segments perfused by significantly stenosed epicardial vessels with distal lumen diameter and perfusion territory considered too small to warrant CABG. At 6-month follow-up, the mean left ventricular ejection fraction increased from 0.61 to 0.65 in Tc-PPI-negative patients (p = 0.01), but not in perioperative patients with AMI.(ABSTRACT TRUNCATED AT 250 WORDS)

Time to first new myocardial infarction in patients with mild angina and three-vessel disease comparing medicine and early surgery: a CASS registry study of survival. Coronary Artery Surgery Study

Two categories--patients alive and free from new myocardial infarction (MI) and time to first new MI (nonfatal and fatal)--were compared in medical and early surgical groups in the Coronary Artery Surgery Study (CASS) registry with Class I or II angina and three-vessel disease in a six-year follow-up. There were 413 in the medical group and 443 in the early surgical group. A broad definition of MI using ECG and clinical criteria on hospital discharge and follow-up was used to include as many new MIs as possible, including perioperative MIs. Stratification was by left ventricular wall motion score and number of proximal segment stenoses and by quintile of propensity score to reduce selection bias in therapy groups. Adjusted by propensity analysis, 79% of medical and 88% of surgical patients (p = .005) were free from new MI; death without diagnosis of new MI was censored. Similarly adjusted, 57% of medical and 76% of surgical patients (p less than .0001) were alive and free from new MI at six years. For patients with previous MI, surgery offered the probability of protection from new MI: with multiple prior MIs, 66% of medical and 88% of surgical patients were free from new MI at six years (p = .0019). This is a nonrandomized, observational study with the limitations of such studies: the need to adjust for differences in baseline traits in medical and surgical groups and the unknown effects of unobserved variables. Fifty-one variables, including therapy, were tested by Cox model with time to new MI as the end point. Early surgery was the strongest independent predictor of freedom from new MI (p = .002) with a relative risk of 51% compared with medical therapy (95% confidence limits of 33 to 78%). In patients with multiple prior MIs, the new MI risk with early surgery was 24% of that for medicine, with an upper 95% confidence point of 64%.

Non-Q-wave myocardial infarction

The rationale for introducing the term "non-Q-wave myocardial infarction" is identified. The incidence, pathology, pathogenesis, and diagnostic criteria for this condition, previously identified as nontransmural or subendocardial infarction, are reviewed. In reviewing the diagnostic criteria, the various noninvasive techniques that may be applied are discussed. The clinical course, prognosis, and management are discussed under the headings of early postinfarction period, late clinical course, predischarge evaluation, and long-term care. The issues of the management of infarct extension and acute interventional therapy are raised and reviewed. Suggestions regarding specific aspects of therapy in non-Q-wave myocardial infarction are included in the summary.