The impact of preoperative evaluation on perioperative events in patients undergoing cataract surgery: a cohort study.

PurposeAmbulatory surgery is a major area of surgical and anesthetic practice, and preoperative clinics are being increasingly used for low-risk surgical procedures. This study investigated the impact of preoperative evaluation on perioperative events in patients undergoing cataract surgery.MethodsThis was a retrospective cohort study of 968 consecutive patients undergoing cataract surgery. Details of medical conditions, surgical, anesthetic, and postoperative information were collected from medical records. A logistic regression model was developed using propensity score adjustment for baseline characteristics.ResultsOut 968 patients included, 240 (24.7%) underwent outpatient preoperative evaluation. There were no perioperative major cardiovascular events. Hypertension occurred in 319 (33%) patients, accounting for 79.7% of all adverse events. Preoperative evaluation resulted in a lower hypertension rate after adjustment for propensity score (OR=0.6; 95% CI 0.41-0.93); no effects were observed on posterior capsule rupture and emergency visits/hospitalization within 7 days of surgery. Eighty-nine patients (9.3%) had an initial systolic pressure ≥180 mm Hg, which was not associated with higher risk of posterior capsule rupture (P=0.158) or postoperative adverse events (P=0.902). Median waiting time to surgery was 6 and 2 months for evaluated and non-evaluated patients, respectively (P<0.001).ConclusionsIn the context of low-risk surgery and no major perioperative and postoperative outcomes, it appears that outpatient preoperative evaluation has no role in reducing adverse events in cataract surgery candidates. Despite fewer hypertensive episodes observed in evaluated patients, these episodes were not associated with any medical or surgical outcomes.

Accuracy of nutritional assessment tools for predicting adverse hospital outcomes.

BACKGROUND AND AIMS: The ability of nutritional status assessment methods to predict clinical outcomes in hospitalized patients has not been completely evaluated. This study compared the accuracy of traditionally used nutritional tools and parameters in predicting death, infection, and length of hospital stay (LOS) in hospitalized adults. RESEARCH METHODS & PROCEDURES: Patients admitted at clinical and surgical wards were evaluated by body mass index, percentage of weight loss, Subjective Global Assessment, albumin, lymphocyte count, and followed until discharge. Clinical outcomes considered were in-hospital death, infection, and LOS. Overall accuracy of each method to predict these outcomes was assessed from ROC curves and C-statistic. RESULTS: Among 434 patients evaluated, 51% had a prolonged LOS, 23% developed infection, and 7.8% died during hospitalization. In univariate analysis, serum albumin was the strongest predictive parameter for death (Cstatistic: 0.77; CI95%: 0.69-0.86) and hospital infection (C-statistic: 0.67; CI95%: 0.61-0.74). For longer stay, lymphocyte count (C-statistic: 0.60; CI95%: 0.55-0.65) emerged as the most predictive variable. After adjustment for non-surgical hospitalization and cancer diagnosis, weight loss > 5% (OR: 1.58; CI95%: 1.06-3.35), and serum albumin < 3.5 g/dL (OR: 2.40; CI95%: 1.46-3.94) were associated to LOS. Albumin was the only independent variable related to infection (OR: 5.01; CI95%: 3.06-8.18) and, for hospital death, albumin (OR: 7.20; CI95%: 3.39-15.32) adjusted for age (OR: 1.03; CI95%: 1.01-1.06). CONCLUSIONS: Nutritional assessment methods evaluated were weakly predictors of hospital outcomes. Except for low serum albumin, isolated use of these methods adds little information in identifying the effect of nutritional status on clinically relevant outcomes.

Coronary artery disease in Brazil: contemporary management and future perspectives.

Cardiovascular diseases are responsible for 32% of total mortality in Brazil, mostly due to cerebrovascular and coronary artery disease. Epidemiological and socio-economical factors play a pivotal role on the distribution, severity and management of coronary artery disease, and the burden is greater in the southeast and south regions of the country, with a higher mortality in low-income populations. The Brazilian healthcare structure is divided into two complementary systems-public and private-but 75% of the population is covered exclusively by the public system. Some Brazilian institutions offer state-of-the-art care to patients with acute and chronic coronary artery disease, but regional inequalities in medical care are still significant. National policies will have to be implemented to fight risk factors, to ensure primary prevention strategies, including assistance on drugs with known protective effects, areas to be tackled by both the private and the public health sectors. Finally, large investments will have to be made to improve tertiary care, to reorganise systems of care for acute patients and mainly to ensure prompt access and continuity of cardiac care and secondary prevention strategies for the whole population.

Compliance with a critical pathway for the management of febrile neutropenia and impact on clinical outcomes.

Febrile neutropenia is associated with significant morbidity and mortality. Managing infectious in neutropenic patients remains a dynamic process, making necessary timely and efficient empirical antibiotic therapy. The implementation of critical pathways has been suggested as a strategy to improve clinical effectiveness. This study evaluated the compliance with an institutional critical pathway for the management of febrile neutropenia and the impact on clinical outcomes at Hospital de Clínicas de Porto Alegre, Brazil (HCPA). We performed a cohort study that prospectively included patients hospitalized from January 2004 to December 2005 and presented febrile neutropenia (190 episodes). Historical controls were selected from March 2001 to April 2003 (193 episodes) before the critical pathway was introduced. This study showed a low rate of full compliance (21.6%; 95% CI 15.7-27.5) with the critical pathway. In most cases, there was partial compliance (67.9%; 95% CI 61.3-74.5). Despite the moderate adherence observed, we recorded a decrease in in-hospital all-cause mortality in the sample studied after protocol implementation (from 24.4 to 14.4%; P = 0.017) and reduction in the length of use of cephalosporin and quinolones. In conclusion, implementation of a critical pathway seems to be an effective strategy to improve clinical outcomes in patients hospitalized with febrile neutropenia.

Association between early detection of soluble TNF-receptors and mortality in burn patients.

OBJECTIVES: To describe early sequential profiling of circulating levels of tumor necrosis factor alpha (TNF-alpha), TNF-1 and TNF-2 soluble receptors (sTNFR1 and sTNFR2), and of endothelin (ET-1) in patients with severe burn injury, and its association with mortality. DESIGN: Prospective study. SETTING: Intensive Care Burn Unit at a community hospital. PATIENTS: Twenty patients with total burn surface area (TBSA)> or = 30%. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Patients were enrolled within 6 h from the injury. Blood samples were drawn at zero, 6, 12, and 24 h for sequential ELISA measurement of plasma marker levels. Data are expressed as mean+/-SD. Age, TBSA, and inhalation injury were not significantly different between survivors ( n=9; 30+/-13 years, TBSA 40+/-12%) and nonsurvivors ( n=11, 38+/-15 years, TBSA 56+/-20%). sTNFR1 levels were increased in nonsurvivors (2937+/-1676 pg/ml; 4548+/-1436 pg/ml) as compared to survivors (1313+/-561 pg/ml; 2561+/-804 pg/ml) at 6 h and 24 h, respectively ( P=0.01 and 0.002). sTNFR2 levels were significantly increased in nonsurvivors (4617+/-1,876 pg/ml vs 2611+/-1,326 pg/ml) only at 6 h ( P=0.015). TNF-alpha and ET-1 levels were not different between nonsurvivors and survivors. After adjustment for TBSA, sTNFR1 and sTNFR2 remained significantly higher in nonsurvivors. CONCLUSION: Early and progressive increase in sTNFR1 and sTNFR2 levels is associated with higher risk for poor outcome in severely burned patients.

Right heart catheterization and cardiac complications in patients undergoing noncardiac surgery: an observational study.

CONTEXT: Right heart catheterization (RHC) is commonly performed before high-risk noncardiac surgery, but the benefit of this strategy remains unproven. OBJECTIVE: To evaluate the relationship between use of perioperative RHC and postoperative cardiac complication rates in patients undergoing major noncardiac surgery. DESIGN: Prospective, observational cohort study. SETTING: Tertiary care teaching hospital in the United States. PATIENTS: Patients (n = 4059 aged >/=50 years) who underwent major elective noncardiac procedures with an expected length of stay of 2 or more days between July 18, 1989, and February 28, 1994. Two hundred twenty one patients had RHC and 3838 did not. MAIN OUTCOME MEASURE: Combined end point of major postoperative cardiac events, including myocardial infarction, unstable angina, cardiogenic pulmonary edema, ventricular fibrillation, documented ventricular tachycardia or primary cardiac arrest, and sustained complete heart block, classified by a reviewer blinded to preoperative data. RESULTS: Major cardiac events occurred in 171 patients (4.2%). Patients who underwent perioperative RHC had a 3-fold increase in incidence of major postoperative cardiac events (34 [15.4%] vs 137 [3.6%]; P<.001). In multivariate analyses, the adjusted odds ratios (ORs) for postoperative major cardiac and noncardiac events in patients undergoing RHC were 2.0 (95% confidence interval [CI], 1.3-3.2) and 2.1 (95% CI, 1.2-3.5), respectively. In a case-control analysis of a subset of 215 matched pairs of patients who did and did not undergo RHC, adjusted for propensity of RHC and type of procedure, patients who underwent perioperative RHC also had increased risk of postoperative congestive heart failure (OR, 2.9; 95% CI, 1.4-6.2) and major noncardiac events (OR, 2.2; 95% CI, 1.4-4.9). CONCLUSIONS: No evidence was found of reduction in complication rates associated with use of perioperative RHC in this population. Because of the morbidity and the high costs associated with RHC, the impact of this intervention in perioperative care should be evaluated in randomized trials.

Impact of age on perioperative complications and length of stay in patients undergoing noncardiac surgery.

BACKGROUND: Major surgical procedures are performed with increasing frequency in elderly persons, but the impact of age on resource use and outcomes is uncertain. OBJECTIVE: To evaluate the influence of age on perioperative cardiac and noncardiac complications and length of stay in patients undergoing noncardiac surgery. DESIGN: Prospective cohort study. SETTING: Urban academic medical center. PATIENTS: Consecutive sample of 4315 patients 50 years of age or older who underwent nonemergent major noncardiac procedures. MEASUREMENTS: Major perioperative complications (cardiac and noncardiac), in-hospital mortality, and length of stay. RESULTS: Major perioperative complications occurred in 4.3% (44 of 1015) of patients 59 years of age or younger, 5.7% (93 of 1646) of patients 60 to 69 years of age, 9.6% (129 of 1341) of patients 70 to 79 years of age, and 12.5% (39 of 313) of patients 80 years of age or older (P < 0.001). In-hospital mortality was significantly higher in patients 80 years of age or older than in those younger than 80 years of age (0.7% vs. 2.6%, respectively). Multivariate analyses indicated an increased odds ratio for perioperative complications or in-hospital mortality in patients 70 to 79 years of age (1.8 [95% CI, 1.2 to 2.7]) and those 80 years of age or older (OR, 2.1 [CI, 1.2 to 3.6]) compared with patients 50 to 59 years of age. Patients 80 years of age or older stayed an average of 1 day more in the hospital, after adjustment for other clinical data (P = 0.001). CONCLUSIONS: Elderly patients had a higher rate of major perioperative complications and mortality after noncardiac surgery and a longer length of stay, but even in patients 80 years of age or older, mortality was low.

Usefulness of transthoracic echocardiography as a tool for risk stratification of patients undergoing major noncardiac surgery.

Transthoracic echocardiography (TTE) is frequently ordered before noncardiac surgery, although its ability to predict perioperative cardiac complications is uncertain. To evaluate the incremental information provided by TTE after consideration of clinical data for prediction of cardiac complications after noncardiac surgery, 570 patients who underwent TTE before major noncardiac surgery at a university hospital were studied. Preoperative clinical data and clinical outcomes were collected prospectively according to a structured protocol. TTE data included left ventricular (LV) function, hypertrophy indexes, and Doppler-derived measurements. In univariate analyses, preoperative systolic dysfunction was associated with postoperative myocardial infarction (odds ratio [OR] 2.8, 95% confidence interval [CI] 1.1 to 7.0), cardiogenic pulmonary edema (OR 3.2, 95% CI 1.4 to 7.0), and major cardiac complications (OR 2.4, 95% Cl 1.3 to 4.5). Moderate to severe LV hypertrophy, moderate to severe mitral regurgitation, and increased aortic valve gradient were also associated with major cardiac events (OR 2.3, 95% CI 1.2 to 4.6; OR 2.2, 95% CI 1.1 to 4.3; OR 2.1, 95% CI 1.0 to 4.5, respectively). In logistic regression analysis, models with echocardiographic variables predicted major cardiac complications significantly better than those that included only clinical variables (c statistic 0.73 vs 0.68; p <0.05). Echocardiographic data added significant information for patients at increased risk for cardiac complications by clinical criteria, but not in otherwise low-risk patients. In conclusion, preoperative TTE before noncardiac surgery can provide independent information about the risk of postoperative cardiac complications in selected patients.

Outcome following isolated tricuspid valve replacement.

OBJECTIVES: The clinical outcome of isolated tricuspid valve replacement is not well defined because this procedure is usually performed concomitantly with other valve surgery. METHODS: We retrospectively studied the short and long-term outcome of 15 consecutive patients (six men and nine women, aged 61+/-3 years) undergoing isolated tricuspid valve replacement from 1984 to 1996. The cause of valve dysfunction was rheumatic heart disease in 12 patients, healed endocarditis in two patients, and sarcoidosis in one patient. The tricuspid valve was stenotic in one patient, regurgitant in eight patients, and both stenotic and regurgitant in six patients. A St. Jude Medical prosthesis was placed in eight patients, Carpentier-Edwards in five patients, and Björk-Shiley and Starr-Edwards in one patient each. RESULTS: The median survival was only 1.2 years. Three patients (20%) died < or =30 days after the surgery or before discharge, and six other patients (40%) died within 3 years of surgery. Anasarca was the only predictor of short-term mortality (P=0.03), while the predictors of long-term mortality were anemia (P=0.01), rheumatic heart disease (P=0.04), previous stroke (P=0.04), and previous mitral valve surgery (P=0.04). CONCLUSIONS: Isolated tricuspid valve replacement is characterized by a poor short and long-term outcome.

Quality of care and hospital readmission in congestive heart failure: an explicit review process.

BACKGROUND: The effect of hospital quality of care on hospital readmission for patients with congestive heart failure (CHF) has not been widely studied. METHODS AND RESULTS: We examined the effects of clinical factors, hospital quality of care, and cardiologist involvement on 3-month readmission rates in patients with CHF by using a 125-item explicit review instrument comprising 3 major domains: admission work-up, evaluation and treatment, and readiness for discharge. During the 3 months after discharge, 59 (30%) of 205 patients were readmitted for CHF. The average evaluation and treatment score was lower for readmitted patients (63% v 58%; P = .04). The specific quality criteria differing between patients readmitted or not readmitted included the performance of any diagnostic evaluation, performance of echocardiography in patients with unknown ejection fraction or suspected valvular disease, and therapy with an angiotensin-converting enzyme inhibitor on discharge. Patients with

Three-dimensional return map: a new tool for quantification of heart rate variability.

BACKGROUND: Several methods are used to study heart rate variability, but they have limitations, which might be overcome by the use of a three-dimensional return map. OBJECTIVES: To evaluate the performance of three-dimensional return map-derived indices to detect (1) sympathetic and parasympathetic modulation to the sinus node and (2) autonomic dysfunction in diabetic patients. METHODS: Six healthy subjects underwent partial and total pharmacological autonomic blockade in a protocol that incorporated vagal and sympathetic predominance. Twenty-two patients with type 2 diabetes mellitus and 12 normal controls participated in the subsequent validation experiment. Three-dimensional return maps were constructed by plotting RRn intervals versus the difference between adjacent RR intervals [(RRn+1)-(RRn)] versus the number of counts, and four derived indices (P1, P2, P3, MN) were created for quantification. RESULTS: Both indices P1 and MN were significantly increased after sympathetic blockade with propranolol, while all indices except P1 were modified after parasympathetic blockade (P < 0.05). During the validation experiments, P1 and MN detected differences between normal controls, and diabetic patients with and without autonomic neuropathy. The overall accuracy of most three-dimensional indices to detect autonomic dysfunction, estimated by the area under the ROC curve, was significantly better than traditional time domain indices. Three-dimensional return map-derived indices also showed adequate reproducibility on two different recording days (intra-class correlation coefficients of 0.69 to 0.82; P < 0.001). CONCLUSIONS: Three-dimensional return map-derived indices are reproducible, quantify parasympathetic as well as sympathetic modulation to the sinus node, and are capable of detecting autonomic dysfunction in diabetic patients.

Increased plasma levels of endothelin 1 and von Willebrand factor in patients with type 2 diabetes and dyslipidemia.

OBJECTIVE: Endothelial markers endothelin 1 (ET-1) and von Willebrand factor (vWF) were assessed in patients with type 2 diabetes and dyslipidemia and in patients with hypercholesterolemia. RESEARCH DESIGN AND METHODS: In this case-control study, plasma ET-and vWF levels were measured by enzyme-linked immunosorbent assay in 35 normoalbuminuric type 2 diabetic patients with dyslipidemia (56+/-5 years), in 21 nondiabetic patients with hypercholesterolemia (52+/-7 years), and in 19 healthy control subjects (45+/-4 years). All of the individuals were normotensive and nonsmokers. Urinary albumin was measured by immunoturbidimetry. RESULTS: ET-1 levels were higher (P<0.0001) in type 2 diabetic dyslipidemic patients (1.62+/-0.73 pg/ml) than in both nondiabetic hypercholesterolemic patients (0.91+/-0.73 pg/ml) and control subjects (0.69+/-0.25 pg/ml). vWF levels were significantly increased (P = 0.02) in type 2 diabetic (185.49+/-72.1%) and hypercholesterolemic (163.29+/-50.7%) patients compared with control subjects (129.70+/-35.2%). In the multiple linear regression analysis. ET-1 was significantly associated (adjusted r2 = 0.42) with serum triglyceride levels (P<0.001), age (P<0.01), insulin sensitivity index (P<0.02), and albuminuria levels (P<0.04). vWF levels were associated (adjusted r2 = 0.22) with albuminuria (P<0.001), fibrinogen levels (P<0.02), and BMI (P<0.03). CONCLUSIONS: Compared with hypercholesterolemic patients, type 2 diabetic patients with dyslipidemia have increased levels of ET-1 and vWF which may indicate more pronounced endothelial injury. These findings appear to be related to components of the insulin resistance syndrome.

Ten-year trends in hospital care for congestive heart failure: improved outcomes and increased use of resources.

BACKGROUND: Scarce data are available on long-term trends in hospital mortality, length of stay (LOS), and costs in congestive heart failure (CHF). OBJECTIVE: To assess 10-year trends in the outcomes of patients hospitalized with CHF. METHODS: We studied all 6676 patients with a primary discharge diagnosis of CHF hospitalized from January 1, 1986, through July 31, 1996, at an academic tertiary care center. Hospital mortality, LOS, and costs were adjusted for sociodemographic characteristics, comorbidities, invasive procedures, hospital disposition, and LOS where appropriate. RESULTS: The mean (+/- SD) age of patients was 70+/-13 years; 54.1% were male; 87.0% were white. There was a significant increasing trend in heart failure severity as assessed by a CHF-specific risk-adjustment index. The proportion of patients who underwent invasive procedures (e.g., cardiac catheterization, coronary angioplasty, coronary artery bypass surgery, defibrillator and pacemaker implantation) was significantly higher in the 1994-1996 period. The standardized mortality ratio (observed mortality/predicted mortality) progressively fell during the study period. Compared with patients admitted before 1991, those admitted after 1991 had a 24% lower observed than predicted mortality. Adjusted LOS exhibited a downward trend, ie, 7.7 days in 1986-1987 to 5.6 days in 1994-1996 (P<.001). Unadjusted cost peaked during 1992-1993 and declined thereafter. Adjusted costs in 1994-1996 were not significantly different from those in 1990-1991. CONCLUSIONS: After risk adjustment for sociodemographic characteristics, comorbidities, and disease severity, a significant decrease in in-hospital mortality was observed during the study decade. This decline in hospital mortality occurred in parallel with decreasing LOS and increasing use of cardiac procedures and costs.

Emergency department triage strategies for acute chest pain using creatine kinase-MB and troponin I assays: a cost-effectiveness analysis.

BACKGROUND: Evaluation of acute chest pain is highly variable. OBJECTIVE: To evaluate the cost-effectiveness of strategies using cardiac markers and noninvasive tests for myocardial ischemia. DESIGN: Cost-effectiveness analysis. DATA SOURCES: Prospective data from 1066 patients with chest pain and from the published literature. TARGET POPULATION: Patients admitted with acute chest pain. TIME HORIZON: Lifetime. PERSPECTIVE: Societal. INTERVENTIONS: Creatine kinase (CK)-MB mass assay alone; CK-MB mass assay followed by cardiac troponin I assay if the CK-MB value is normal; CK-MB mass assay followed by troponin I assay if the CK-MB value is normal and electrocardiography shows ischemic changes; both CK-MB mass and troponin I assays; and troponin I assay alone. These strategies were evaluated alone or in combination with early exercise testing. OUTCOME MEASURES: Lifetime cost, life expectancy (in years), and incremental cost-effectiveness. RESULTS OF BASE-CASE ANALYSIS: For patients 55 to 64 years of age, measurement of CK-MB mass followed by exercise testing in appropriate patients was the most competitive strategy ($43000 per year of life saved). Measurement of CK-MB mass followed by troponin I measurement had an incremental cost-effectiveness ratio of $47400 per year of life saved for patients 65 to 74 years of age; it was also the most cost-effective strategy when early exercise testing could not be performed, CK-MB values were normal, and ischemic changes were seen on electrocardiography. RESULTS OF SENSITIVITY ANALYSIS: Results were influenced by age, probability of myocardial infarction, and medical costs. CONCLUSIONS: Measurement of CK-MB mass plus early exercise testing is a cost-effective initial strategy for younger patients and those with a low to moderate probability of myocardial infarction. Troponin I measurement can be a cost-effective second test in higher-risk subsets of patients if the CK-MB level is normal and early exercise testing is not an option.

Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery.

BACKGROUND: Cardiac complications are important causes of morbidity after noncardiac surgery. The purpose of this prospective cohort study was to develop and validate an index for risk of cardiac complications. METHODS AND RESULTS: We studied 4315 patients aged > or = 50 years undergoing elective major noncardiac procedures in a tertiary-care teaching hospital. The main outcome measures were major cardiac complications. Major cardiac complications occurred in 56 (2%) of 2893 patients assigned to the derivation cohort. Six independent predictors of complications were identified and included in a Revised Cardiac Risk Index: high-risk type of surgery, history of ischemic heart disease, history of congestive heart failure, history of cerebrovascular disease, preoperative treatment with insulin, and preoperative serum creatinine >2.0 mg/dL. Rates of major cardiac complication with 0, 1, 2, or > or = 3 of these factors were 0.5%, 1.3%, 4%, and 9%, respectively, in the derivation cohort and 0.4%, 0.9%, 7%, and 11%, respectively, among 1422 patients in the validation cohort. Receiver operating characteristic curve analysis in the validation cohort indicated that the diagnostic performance of the Revised Cardiac Risk Index was superior to other published risk-prediction indexes. CONCLUSIONS: In stable patients undergoing nonurgent major noncardiac surgery, this index can identify patients at higher risk for complications. This index may be useful for identification of candidates for further risk stratification with noninvasive technologies or other management strategies, as well as low-risk patients in whom additional evaluation is unlikely to be helpful.

A proposed strategy for utilization of creatine kinase-MB and troponin I in the evaluation of acute chest pain.

In recent years, cardiac troponins have attracted great interest as a marker for myocardial injury. However, there are limited data on strategies for use of creatine kinase (CK)-MB and troponin I (cTnI) in clinical practice. We sought to develop a testing strategy using prospectively collected clinical data including serial CK-MB and cTnI levels from 1,051 patients aged > or = 30 years admitted to a teaching hospital for acute chest pain. Diagnostic performance was evaluated for peak values of CK-MB and cTnI obtained during the first 24 hours for the combined end point of acute myocardial infarction and/or major cardiac events within 72 hours. The overall diagnostic accuracy was similar for both cardiac markers alone, and for the combination of cTnI and CK-MB (receiver-operating characteristic curve 0.84, 0.86, and 0.87, respectively). In the multivariate analysis, models including cardiac markers showed that both CK-MB and cTnI added information to clinical data to predict the combined end point, but cTnI added significantly less. Using recursive partitioning analysis, we developed a strategy that would restrict routine cTnI use to patients with normal CK-MB results and findings on the electrocardiogram consistent with ischemia. This strategy would divide patients with suspected myocardial ischemia into 4 groups with risks for the combined end point of 4%, 13%, 26%, and 85%. Thus, cTnI adds information to CK-MB mass and clinical data for predicting major cardiac events, but this contribution is mainly in patients with evidence of myocardial ischemia on their electrocardiograms.