Predictors of postoperative myocardial ischemia in patients undergoing noncardiac surgery.The Study of Perioperative Ischemia Research Group.

OBJECTIVE--To identify predictors of postoperative myocardial ischemia in patients scheduled to undergo major noncardiac surgery. DESIGN--Historical, clinical, laboratory, and physiological data were obtained prospectively before and during surgery to identify potential univariate predictors of postoperative myocardial ischemia, which then were entered into multivariate logistic models. Continuous two-lead electrocardiograms before, during, and after surgery were used to identify episodes of myocardial ischemia. SETTING--Department of Veterans Affairs tertiary care hospital. PATIENTS--A consecutive sample of 474 men at high risk for or with coronary artery disease who were scheduled to undergo major noncardiac surgery (95% compliance rate). MAIN OUTCOME MEASURE--Significant variables identified by multivariate logistic models that are associated with postoperative myocardial ischemia. RESULTS--Five major preoperative predictors of postoperative myocardial ischemia were identified: (1) left ventricular hypertrophy by electrocardiogram; (2) history of hypertension; (3) diabetes mellitus; (4) definite coronary artery disease; and (5) use of digoxin. The risk of postoperative myocardial ischemia increased progressively with the number of predictors present: in 22% of patients with no predictors, in 31% with one predictor, in 46% with two predictors, in 70% with three predictors, and in 77% with four predictors. CONCLUSION--Patients subgroups who are at high risk for developing postoperative myocardial ischemia and who might benefit the most from intensive Holter monitoring in the postoperative period now can be identified preoperatively.     

Long-term cardiac prognosis following noncardiac surgery. The Study of Perioperative Ischemia Research Group.

OBJECTIVE--To determine the long-term (2-year) cardiac prognosis of high-risk patients undergoing noncardiac surgery and to determine the predictors of long-term adverse cardiac outcome. DESIGN--Prospective cohort study. Historical, clinical, and laboratory data were collected during the in-hospital period, and at 6 months, 1 year, and 2 years following surgery. Data were analyzed using proportional hazards models. SETTING--University-affiliated Veterans Affairs medical center. POPULATION--A consecutive sample of 444 patients with or at high risk for coronary artery disease who had undergone elective noncardiac surgery and were discharged from the hospital in stable condition. MAIN OUTCOME MEASURES--Cardiac death, myocardial infarction, unstable angina, progressive angina requiring coronary artery bypass graft surgery or coronary angioplasty, and new unstable angina requiring hospitalization. RESULTS--Forty-seven patients (11%) had major cardiovascular complications during a 728-day (median) follow-up period: 24 had cardiac death; 11, nonfatal myocardial infarction; six, progressive angina requiring coronary artery bypass graft surgery or coronary angioplasty; and six, new unstable angina requiring hospitalization. Thirty percent of outcomes occurred within 6 months of surgery and 64% within 1 year. Five independent predictors of long-term outcome were identified. Three predictors reflected the preexisting chronic disease state: (1) the presence of known vascular disease (hazard ratio, 6.1; 95% confidence interval [CI], 2.5 to 15.0; P less than .0001); (2) a history of congestive heart failure (hazard ratio, 5.0; 95% CI, 2.0 to 12.0; P less than .0005); and (3) known coronary artery disease (hazard ratio, 3.7; 95% CI, 1.7 to 8.0; P less than .0007). Two predictors reflected acute postoperative ischemic events: (1) myocardial infarction/unstable angina (hazard ratio, 20; 95% CI, 7.5 to 53.0; P less than .0001) and (2) myocardial ischemia (hazard ratio, 2.2; 95% CI, 1.1 to 4.3; P less than .03). Patients surviving a postoperative in-hospital myocardial infarction had a 28-fold increase in the rate of subsequent cardiac complications within 6 months following surgery, a 15-fold increase within 1 year, and a 14-fold increase within 2 years (95% CI, 5.8 to 32; P less than .00001). Seventy percent of all long-term adverse outcomes were preceded by in-hospital postoperative ischemia that occurred at least 30 days (median, 282 days) before the long-term event. The development of congestive heart failure or ventricular tachycardia (without ischemia) during hospitalization was not associated with adverse long-term outcome. CONCLUSIONS--The incidence of long-term adverse cardiac outcomes following noncardiac surgery is substantial. At increased risk are patients with chronic cardiovascular disease; at highest risk are patients with acute perioperative ischemic events. We conclude that survivors of in-hospital perioperative ischemic events, specifically myocardial infarction, unstable angina, and postoperative ischemia, warrant more aggressive long-term follow-up and treatment than is currently practiced.     

Ventricular arrhythmias in patients undergoing noncardiac surgery. The Study of Perioperative Ischemia Research Group.

OBJECTIVE--To determine the incidence, clinical predictors and prognostic importance of perioperative ventricular arrhythmias. DESIGN--Prospective cohort study (Study of Perioperative Ischemia). SETTING--University-affiliated Department of Veterans Affairs Medical Center, San Francisco, Calif. SUBJECTS--A consecutive sample of 230 male patients, with known coronary artery disease (46%) or at high risk of coronary artery disease (54%), undergoing major noncardiac surgical procedures. MEASUREMENTS--We recorded cardiac rhythm throughout the preoperative (mean = 21 hours), intraoperative (mean = 6 hours), and postoperative (mean = 38 hours) periods using continuous ambulatory electrocardiographic monitoring. Adverse cardiac outcomes were noted by physicians blinded to information about arrhythmias. MAIN RESULTS--Frequent or major ventricular arrhythmias (greater than 30 ventricular ectopic beats per hour, ventricular tachycardia) occurred in 44% of our patients: 21% preoperatively, 16% intraoperatively, and 36% postoperatively. Compared with the preoperative baseline, the severity of arrhythmia increased in only 2% of patients intraoperatively but in 10% postoperatively. Preoperative ventricular arrhythmias were more common in smokers (odds ratio [OR], 4.1; 95% confidence interval [CI], 1.2 to 15.0), those with a history of congestive heart failure (OR, 4.1; 95% CI, 1.9 to 9.0), and those with electrocardiographic evidence of myocardial ischemia (OR, 2.2; 95% CI, 1.1 to 4.7). Preoperative arrhythmias were associated with the occurrence of intraoperative and postoperative arrhythmias (OR, 7.3; 95% CI, 3.3 to 16.0, and OR, 6.4; 95% CI, 2.7 to 15.0, respectively). Nonfatal myocardial infarction or cardiac death occurred in nine men; these outcomes were not significantly more frequent in those with prior perioperative arrhythmias, albeit with wide CIs (OR, 1.6; 95% CI, 0.4 to 6.2). CONCLUSION--Almost half of all high-risk patients undergoing noncardiac surgery have frequent ventricular ectopic beats or nonsustained ventricular tachycardia. Our results suggest that these arrhythmias, when they occur without other signs or symptoms of myocardial infarction, may not require aggressive monitoring or treatment during the perioperative period.     

In-hospital and long-term mortality in male veterans following noncardiac surgery. The Study of Perioperative Ischemia Research Group.

OBJECTIVES--To determine the causes of and risk factors for mortality following noncardiac surgery. DESIGN--Prospective cohort study. SETTING--A university-affiliated Veterans Affairs medical center. PATIENTS--Consecutive series of 474 men between the ages of 38 and 89 years (mean age, 68 years) who were undergoing major noncardiac surgery involving general anesthesia. All subjects had known coronary artery disease or were at high risk for coronary artery disease. MEASUREMENTS AND RESULTS--During the initial hospitalization, 26 patients (5%) died, most commonly from sepsis (n = 6) or cardiac diseases (n = 6). Deaths occurred from postoperative days 2 to 69; half occurred more than 3 weeks after surgery. Multivariable analysis disclosed that a history of hypertension (odds ratio [OR] = 3.8; 95% confidence interval [CI], 1.1 to 13), a severely limited activity level (OR = 9.7; 95% CI, 2.5 to 37), and a creatinine clearance of less than 0.83 mL/s (OR = 6.8; 95% CI, 2.8 to 16) were all independently associated with an increased risk of postoperative mortality. The mortality rate in patients with two or more of these risk factors was 20%, nearly eight times higher (95% CI, 3.6 to 16) than those with one or no risk factors. An additional 82 patients died within the next 2 years; cancer, renal dysfunction, congestive heart failure, and obstructive pulmonary disease were independently associated with long-term mortality. CONCLUSIONS--Even in patients at high risk of cardiac complications following surgery, noncardiac causes of death are more common. Patients with a history of hypertension, severely limited activity, and reduced renal function appear to be at especially high risk of in-hospital mortality after noncardiac surgery.     

EASI导联与常规12导联心电图诊断心肌缺血价值对比研究

目的:比较EASI导联心电图在诊断心肌缺血中的临床价值.方法:选择心肌缺血患者200例,均记录其12导联及EASI导联心电图,统计EASI导联组与常规12导联心电图组诊断心律失常效果,及动态心电图检查中的价值与心电图ST-T改变幅度.结果:EASI导联组检出房性早搏、室性早搏、房室传导阻滞及心肌缺血比例高于常规12导联心电图组(P＜0.05),EASI导联组发生电极滑脱、基线漂移及肌电干扰比例低于常规12导联心电图组(P＜0.05),EASI导联组检出ST-T上抬幅度大于常规12导联心电图组(P＜0.05),ST-T下移幅度大于常规12导联心电图组(P＜0.05).结论:EA-SI导联诊断心肌缺血所受外界干扰小,尤其适用于长时间检查诊断.     

体表标准12导联心电图对冠状动脉疾病诊断的价值和意义

慢性冠状动脉供血不足的体表标准12导联心电图(ST-T改变)对冠状动脉疾病诊断是无价值的,属于一种推测性、主观的判断。心电图存在持续性ST-T改变时,多数由其他因素引起的。对于前壁AM I患者,用avR导联ST段抬高大于等于V1导联ST段抬高的指标,可以鉴别是LM还是LAD的闭塞。对下壁AM I患者,用ST V3\Ⅲ值既可以对RCA闭塞定位,又可区别出IRA是RCA还是LCX。另外,Ⅰ、avL导联ST段变化也可以作为鉴别RCA和LCX闭塞的指标。高侧壁AM I患者IRA的定位,主要根据它合并哪个壁的梗死。后间壁AM I心电图诊断标准为:①下壁AM I时伴V1导联ST段明显抬高≥2mm;②ST段抬高的幅度呈V1>V2>V3和V1>V3R>V4R。     

Appendicular bone density and age predict hip fracture in women. The Study of Osteoporotic Fractures Research Group

To determine whether measurement of bone density predicts hip fracture in women, we prospectively studied 9703 nonblack women aged 65 years and older who had measurements of bone mineral density using single-photon absorptiometry in the calcaneus, distal radius, and proximal radius. During an average of 1.6 years of follow-up, 53 hip fractures occurred. The risk of hip fracture was inversely related to bone density at all three measurement sites. After adjusting for age, the relative risk of hip fracture was 1.66 for a decrease of 1 SD in the bone density at the calcaneus (95% confidence interval, 1.22 to 2.26), 1.55 (95% confidence interval, 1.13 to 2.11) at the distal radius, and 1.41 (95% confidence interval, 1.06 to 1.88) at the proximal radius. None of the three measurements was a significantly better predictor of hip fracture than the others. After adjusting for bone mineral density, the risk of hip fracture doubled for each 10-year increase in age (relative risk, 2.09; 95% confidence interval, 1.31 to 3.33). We conclude that decreased bone density in the appendicular skeleton is associated with an increased risk of hip fracture, but this accounts for only part of the age-related increase in risk of hip fracture among older women.     

A comparison of methods for the estimation of plasma low- and very low-density lipoprotein cholesterol. The Lipid Research Clinics Prevalence Study

Using data from over 10 000 men, women, and children who participated in the Lipid Research Clinics prevalence studies, we have examined the formula adopted by Friedewald et al for estimating plasma or serum concentrations of low-density lipoprotein cholesterol (LDL-C) when (for economy, or in the absence of an ultracentrifuge) only fasting total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG) concentrations are measured in milligrams per liter, ie, LDL-C = TC-(HDL-C + 0.20 X TG). Values for LDL-C obtained by use of the Friedewald formula were compared with values derived from the Lipid Research Clinics ultracentrifugal procedure for LDL-C, which was used as a reference. Participants who were pregnant, who had not fasted, or whose plasma contained chylomicrons or floating beta-lipoproteins were excluded. We concluded that a better estimator for LDL-C was provided by the equation LDL-C = TC-(HDL-C + 0.16 X TG), since it produced an error (relative to the reference method) of lesser magnitude than the previous formula. The expression 0.16 X TG (0.37 X TG when measurements are reported in millimoles per liter) also produced a more accurate estimate of very low-density lipoprotein cholesterol relative to values obtained by the standard Lipid Research Clinics procedure for this component. The proposed formula is more precise for plasmas or sera with a TG concentration within the normal range.     

Rifampin and pyrazinamide vs isoniazid for prevention of tuberculosis in HIV-infected persons: an international randomized trial. Terry Beirn Community Programs for Clinical Research on AIDS, the Adult AIDS Clinical Trials Group, the Pan American Health Organization, and the Centers for Disease Control and Prevention Study Group

Context  Because of problems with adherence, toxicity, and increasing resistance associated with 6- to 12-month isoniazid regimens, an alternative short-course tuberculosis preventive regimen is needed. Objective  To compare a 2-month regimen of daily rifampin and pyrazinamide with a 12-month regimen of daily isoniazid in preventing tuberculosis in persons with human immunodeficiency virus (HIV) infection. Design  Randomized, open-label controlled trial conducted from September 1991 to May 1996, with follow-up through October 1997. Setting  Outpatient clinics in the United States, Mexico, Haiti, and Brazil. Participants  A total of 1583 HIV-positive persons aged 13 years or older with a positive tuberculin skin test result. Interventions  Patients were randomized to isoniazid, 300 mg/d, with pyridoxine hydrochloride for 12 months (n = 792) or rifampin, 600 mg/d, and pyrazinamide, 20 mg/kg per day, for 2 months (n = 791). Main Outcome Measures  The primary end point was culture-confirmed tuberculosis; secondary end points were proven or probable tuberculosis, adverse events, and death, compared by treatment group. Results  Of patients assigned to rifampin and pyrazinamide, 80% completed the regimen compared with 69% assigned to isoniazid (P<.001). After a mean follow-up of 37 months, 19 patients (2.4%) assigned to rifampin and pyrazinamide and 26 (3.3%) assigned to isoniazid developed confirmed tuberculosis at rates of 0.8 and 1.1 per 100 person-years, respectively (risk ratio, 0.72 [95% confidence interval, 0.40-1.31]; P = .28). In multivariate analysis, there were no significant differences in rates for confirmed or probable tuberculosis (P = .83), HIV progression and/or death (P = .09), or overall adverse events (P = .27), although drug discontinuation was slightly higher in the rifampin and pyrazinamide group (P = .01). Neither regimen appeared to lead to the development of drug-resistant tuberculosis. Conclusions  Our data suggest that for preventing tuberculosis in HIV-infected patients, a daily 2-month regimen of rifampin and pyrazinamide is similar in safety and efficacy to a daily 12-month regimen of isoniazid. This shorter regimen offers practical advantages to both patients and tuberculosis control programs.