Should my outpatient center have a beta-blocker protocol?

PURPOSE OF REVIEW: Perioperative beta-blockade has been advocated by multiple authors and recent guidelines as a strategy to reduce cardiac risk in noncardiac surgery. Knowledge about application of this treatment modality to the ambulatory surgery population is poor. RECENT FINDINGS: Although the initial trial in patients with a positive stress test undergoing major vascular surgery demonstrated significantly fewer perioperative cardiac events among those randomized to perioperative beta-blocker therapy, more recent studies in patients without documented coronary artery disease undergoing major noncardiac surgical procedures were unable to demonstrate efficacy. Guidelines from the American Heart Association/American College of Cardiology have been reported and advocated class I recommendations for perioperative beta-blockade only for patients previously taking beta-blockers and those patients with a positive stress test undergoing vascular surgery. There was insufficient evidence to make a recommendation in low-risk surgery. SUMMARY: Based upon the available evidence and guidelines, patients currently taking beta-blockers and undergoing ambulatory surgery should continue these agents and protocols employing this strategy should be beneficial. In patients who are not currently taking beta-blockers and in whom long-term therapy is not warranted, current evidence does not support instituting prophylactic therapy in the ambulatory surgery population.     

Preoperative cardiac risk assessment: an updated approach.

HYPOTHESIS: We provide an updated algorithm for approaching preoperative cardiac risk assessment in patients undergoing noncardiac surgery. DESIGN: A National Library of Medicine PubMed literature search was performed dating back to 1985 using the keywords "preoperative cardiac risk for noncardiac surgery." This search was restricted to English language articles involving human subjects. RESULTS: Patient-specific and operation-specific cardiac risk can be determined clinically. Patients with major cardiac risk factors have a high incidence of perioperative cardiac complications, whereas the risk is less than 3% for low-risk patients. For intermediate-risk patients, no prospective randomized studies demonstrate the efficacy of noninvasive stress testing (dipyridamole thallium or dobutamine echocardiography) or of subsequent coronary revascularization for preventing perioperative cardiac complications. Recent studies demonstrate that perioperative beta-blockade significantly reduces the adverse cardiac event rate in intermediate-risk patients. CONCLUSIONS: Most patients with high cardiac risk should proceed with coronary angiography. Patients with low cardiac risk can proceed to surgery without noninvasive testing. For intermediate-risk patients, consideration may be given to further stress testing prior to surgery; however, in most patients, proceeding to surgery with perioperative beta-blockade is an acceptable alternative.     

The role of a defined protocol for cardiac risk assessment in decreasing perioperative myocardial infarction in vascular surgery.

Major elective peripheral vascular surgery has historically carried a significant risk of perioperative myocardial infarction; this risk has been quantified further by its association with proved reduction in cardiac reserve/presence of coronary artery disease by stress testing or invasive monitoring. Recognition of this risk logically should lead to protocols that delineate coronary artery disease/cardiac reserve before surgery and correct for observed abnormalities during surgery. This study sought to show that a coherent algorithm of preoperative cardiac assessment combined with aggressive perioperative management could indeed reduce perioperative myocardial infarction rates. Six hundred thirty consecutive elective vascular operations were performed by the author during 6 years. All patients were entered into a prospective protocol for preoperative cardiac risk assessment, which then determined the choice of operation, type of anesthesia, and level of hemodynamic monitoring. Sixty-eight percent of the patients demonstrated clinical coronary artery disease, 15% had previously undergone coronary catheterization or surgery, and 9% had ejection fractions less than 35%. All patients underwent baseline detailed cardiac histories, radionuclide cardioangiography, and electrocardiograms. Patients with significant historic coronary artery disease or ejection fraction less than 50% underwent stress thallium testing; patients with positive fixed or redistribution defects then underwent catheterization, constituting 7% of the series. Risk stratification by age and cardiac assessment then dictated the perioperative care. The overall perioperative myocardial infarction rate was 0.7% (5/628), ranging from 0% for 156 aortic operations and 114 carotid endarterectomies to 0.6% for 159 femoropopliteal and 3.3% for 90 femorotibial revascularizations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Successful implementation of perioperative betablockade utilizing a multidisciplinary approach

PURPOSE: To describe how we implemented a protocol for perioperative beta-blockade in patients with or at risk of coronary artery disease (CAD) undergoing major non-cardiac surgery and to present our results. METHODS: After institutional approval, from May 1999 to April 2001, patients with surgical and medical indications (CAD as indicated by previous myocardial infarction, typical angina or atypical angina with a positive stress test or at least two risk factors for CAD: age 65 yr, hypertension, smoking, high cholesterol, diabetes mellitus) for perioperative beta-blockade were identified preoperatively by anesthesiology and referred to the General Internal Medicine Service (MED). MED initiated patients on outpatient beta-blockers. The intraoperative anesthetic management was left to the discretion of the anesthesiologist. In the postanesthesia care unit (PACU), patients received iv metoprolol according to hemodynamic criteria. Postoperatively, patients were followed by MED for adverse cardiac events. RESULTS: Sixty-nine patients received perioperative beta-blockade. Preoperatively, 60% were started on metoprolol, 39% on atenolol and 1% on propranolol. In PACU, 42%, 9% and 38% of patients were given iv metoprolol 0, 5 and 10 mg respectively. One patient was given glycopyrrolate in the PACU for bradycardia and none received vasoactive or inotropic agents. Three patients (4.3%) had postoperative cardiac events. CONCLUSIONS: With close collaboration between anesthesiologists, internists, PACU nurses and family physicians, a strategy for perioperative beta-blockade was implemented successfully in patients with cardiac risks. Beta-blockade was associated with few side effects and morbidities.     

An Appraisal of Different Cardiac Risk Reduction Strategies in Vascular Surgery Patients

OBJECTIVES: to summarize existing evidence regarding the benefits and the risks of all available interventional and medical means aimed at cardiac risk reduction in patients undergoing vascular surgery. DESIGN: review of the literature. MATERIALS AND METHODS: a critical review of all studies examining the impact of various prophylactic cardiac maneuvers on perioperative outcome following vascular surgery was performed. Overall mortality, cardiac mortality and myocardial infarction rate were used as the outcome measures. RESULTS: coronary artery bypass grafting is associated with a 60% decrease in perioperative mortality in patients undergoing vascular surgery, but in most of the cases this decrease does not outweigh the combined risk of the cardiac and the subsequent noncardiac vascular procedure. Data supporting the cardioprotective effect of percutaneous transluminal angioplasty in the perioperative setting are insufficient. beta-blockade has been shown to decrease perioperative mortality and cardiac morbidity in both high-risk (strong evidence) and low-risk (weak evidence) patients. CONCLUSIONS: coronary revascularization is rarely indicated to simply get the patient through vascular surgery and should be reserved for patients who would need it irrespective of the scheduled vascular procedure. Among all available pharmacological agents, including beta-blockers, alpha-agonists, calcium channel blockers and nitrates, only beta-blockers have been proven to reduce the cardiac risk of vascular surgery.     

Implementing ACC/AHA guidelines for the preoperative management of patients with coronary artery disease scheduled for noncardiac surgery: effect on perioperative outcome

STUDY OBJECTIVE: To review the new consensus guidelines for cardiac testing for the patient with cardiac disease scheduled for elective, noncardiac surgery, and their impact on cardiac functional testing. DESIGN: Retrospective chart review study. SETTING: Tertiary care medical center. PATIENTS: 181 patients scheduled for elective, major surgery who met American College of Cardiology/American Heart Association (ACC/AHA) criteria for a preoperative stress test. INTERVENTIONS: A variety of tests were ordered, including treadmill stress testing, persantine-thallium imaging, dobutamine echocardiography, and exercise stress echocardiography. MEASUREMENTS: The numbers of and outcome of the stress tests and the cardiac outcome of the patients who underwent cardiac testing and surgery were recorded. MAIN RESULTS: Abnormal tests occurred in 27 patients. Two patients declined treatment, eight patients had primary medical management, and the remainder (17) had cardiac catheterization. Results included no lesion (2 patients), angioplasty (4 patients), angioplasty plus stenting (1 patient), coronary artery bypass grafting (CABG) (4 patients), and delineated lesions treated with medical optimization (6 patients). One patient had CABG and declined further surgery. One patient had myocardial infarction 6 months after surgery that was treated by medical management after cardiac catheterization. The other 23 patients had surgery without cardiac complication within 1 year of surgery. Only 15% (27/180) of the patients with indications for a stress test had a positive result. Even fewer patients had any alteration of the perioperative period. Despite this finding, cardiac morbidity was very low. CONCLUSIONS: The guidelines for stress test may be over-sensitive, and further prospective clinical studies are indicated.     

Preoperative evaluation of cardiac risk using dobutamine-thallium imaging in vascular surgery

Coronary artery disease is frequently present in patients undergoing evaluation for reconstructive peripheral vascular surgery. Dobutamine-thallium imaging has been shown to be a reliable and sensitive noninvasive method for the detection of significant coronary artery disease. Eighty-seven candidates for vascular reconstruction underwent dobutamine-thallium imaging. Forty-eight patients had an abnormal dobutamine-thallium scan. Twenty-two patients had infarct only, while 26 had reversible ischemia demonstrated on dobutamine-thallium imaging. Fourteen of 26 patients with reversible ischemia underwent cardiac catheterization and 11 showed significant coronary artery disease. Seven patients underwent preoperative coronary artery bypass grafting or angioplasty. There were no postoperative myocardial events in this group. Three patients were denied surgery on the basis of unreconstructible coronary artery disease, and one patient refused further intervention. Ten patients with reversible myocardial ischemia on dobutamine-thallium imaging underwent vascular surgical reconstruction without coronary revascularization and suffered a 40% incidence of postoperative myocardial ischemic events. Five patients were denied surgery because of presumed significant coronary artery disease on the basis of the dobutamine-thallium imaging and clinical evaluation alone. Thirty-nine patients with normal dobutamine-thallium scans underwent vascular reconstructive surgery with a 5% incidence of postoperative myocardial ischemia. Dobutamine-thallium imaging is a sensitive and reliable screening method which identifies those patients with coronary artery disease who are at high risk for perioperative myocardial ischemia following peripheral vascular surgery. Presented at the Annual Meeting of the Peripheral Vascular Surgery Society, New York, New York, June 17, 1989.     

Resting gated pool ejection fraction: a poor predictor of perioperative myocardial infarction in patients undergoing vascular surgery for infrainguinal bypass grafting

Ventricular ejection fraction is widely regarded as a prognostic indicator of perioperative myocardial infarction. To evaluate this premise the prevalence of perioperative myocardial infarction or cardiac death was analyzed in relation to preoperative resting gated pool ejection fraction in 85 patients undergoing vascular surgery for infrainguinal bypass grafting. Patients were divided into three groups on the basis of ejection fraction. Group I consisted of 50 patients with ejection fractions of 56% to 92%. Nine (18%) perioperative myocardial infarctions occurred in group I, and there were no cardiac deaths. Group II consisted of 20 patients with ejection fractions of 37% to 55%. Three (15%) myocardial infarctions occurred in this group, and there were no cardiac deaths. Group III included 15 patients with ejection fractions of 20% to 35%. Three (20%) cardiac events occurred in group III including one nonfatal myocardial infarction and two (13%) cardiac deaths. Statistical analysis showed no significant difference in prevalence of cardiac events between any group. These results suggest that resting ejection fraction is a poor predictor of perioperative myocardial infarction in patients undergoing vascular surgery. Patients with normal ejection fractions, but underlying coronary artery disease, are still at significant risk for a perioperative cardiac event.     

Dipyridamole thallium scanning in the evaluation of coronary artery disease in elective abdominal aortic surgery.

Dipyridamole thallium scanning was routinely performed on 68 consecutive patients who presented for elective aortic surgery. All 68 patients were judged by clinical assessment to be at low risk for perioperative cardiac complications. In addition, 42 of 68 patients had a history of myocardial infarction, stable angina, or abnormal echocardiographic findings (group 1). Twenty-six of 68 patients did not have a history of myocardial infarction, angina, or abnormal echocardiographic findings (group 2). In group 1, 34 of 4 patients had positive results on dipyridamole thallium scanning, and 15 of these patients were found to have critical coronary artery disease on subsequent cardiac catheterization; nine underwent immediate coronary artery bypass grafting, and six had their coronary artery disease treated medically and their vascular operations cancelled. The remaining 27 patients in group 1 underwent elective operations, with six (22%) of 27 sustaining postoperative cardiac complications. None of the group 2 patients was found to have critical coronary artery disease. All patients in group 2 underwent aortic operation without cardiac complication. Routine dipyridamole thallium scanning detected a 22% (15 of 68) incidence of critical coronary artery disease overall. There was a 36% (15 of 42) incidence of critical coronary artery disease in group 1 patients vs 0% in group 2 patients (95% confidence interval, 21% to 50%). We conclude that the use of dipyridamole thallium scanning in low-risk patients for cardiac screening prior to elective aortic operations is beneficial in selected patients who have a history of myocardial infarction, angina, or abnormal echocardiographic findings, but is not necessary in patients with no history of coronary artery disease.     

Postoperative outcomes for patients undergoing elective revascularization for critical limb ischemia and intermittent claudication: a subanalysis of the Coronary Artery Revascularization Prophylaxis (CARP) trial

OBJECTIVE: To determine the perioperative mortality, myocardial infarction rate, and long-term survival of patients with critical limb ischemia (CLI) compared with those with intermittent claudication (IC) within a cohort selected for significant coronary artery disease, a secondary analysis was conducted of a prospective, randomized, multicenter trial of Coronary Artery Revascularization Prophylaxis (CARP) before peripheral vascular surgery. This multicenter trial was sponsored by the Cooperative Studies Program of the Department of Veterans Affairs. METHODS: Of the 510 patients enrolled in the CARP trial and randomized to coronary revascularization or no revascularization before elective vascular surgery, 143 had CLI and 164 had IC as an indication for lower limb revascularization; >95% of each group were men. The presence of coronary artery disease was determined by cardiac catheterization. Eligible patients had at least one treatable coronary lesion of > or =70%. Those with significant left main disease, ejection fraction of <20%, and aortic stenosis were excluded. Patients were randomized to coronary artery disease revascularization or no revascularization before vascular surgery and followed for mortality and morbidity perioperatively and for a median of 2.7 years postoperatively. Medical treatment of coronary artery disease was pursued aggressively. RESULTS: Patients with IC had a longer time from randomization to vascular surgery (p = .001) and more abdominal operations (p < .001). Patients with CLI had more urgent operations (p = .006), reoperations (p < .001), and limb loss (p = .008) as well as longer hospital stays (p < .001). The IC group had more perioperative myocardial infarctions (CLI, 8.4%; IC, 17.1%; p = .024), although perioperative mortality was similar (CLI, 3.5%; IC, 1.8%; p = .360). In follow-up, the IC group also had numerically more myocardial infarctions (CLI, 16.8%; IC, 25%; p = .079), but mortality was not different (CLI, 21%; IC, 22%; p = .825). Coronary artery revascularization did not lower perioperative or long-term mortality in either group. CONCLUSIONS: Our data indicate that patients with significant coronary artery disease and either CLI or IC can undergo vascular surgery with low mortality and morbidity, and these results are not improved by coronary artery revascularization before vascular surgery. Furthermore, when selected for the presence of symptomatically stable, severe coronary artery disease, there is no difference in long-term survival between patients with CLI and IC. Finally, the better-than-predicted outcomes for these patients with advanced systemic atherosclerosis may be due to aggressive medical management with beta-blockers, statins, and acetylsalicylic acid.     

Predictors of Cardiac Morbidity And Mortality in Patients Undergoing Endovascular Repair of the Thoracic Aorta

The aim of this study was to determine predictors of cardiac morbidity and mortality in patients undergoing endovascular repair of the thoracic aorta. This was a retrospective cohort study that took place in a University-affiliated county hospital. Preoperative and intraoperative variables were collected from a consecutive series of patients who underwent repair of the thoracic aorta at our institution between 1998 and 2003. Perioperative complications and mortality were identified for each patient. Fifty-nine patients underwent endovascular repair of the thoracic aorta. The endografts were successfully deployed in 58 (98%) patients. Nine (15%) died perioperatively, 4 (7%) from cardiac causes. There were 12 (20%) perioperative cardiac events. A history of myocardial infarction (MI) was the only preoperative risk factor that was predictive of a cardiac event (p = 0.001). The cardiac event rate was 29% for patients who did not receive perioperative beta-blockade vs. 8% in patients who did (p = 0.04). Intraoperative predictors of MI were estimated blood loss (2480 cc vs. 680 cc, p = 0.01), intravenous (IV) fluids (2955 cc vs. 2010 cc, p =0.02), and length of operation (269 min vs. 178 min, p = 0.02). From these results we concluded that mortality associated with endovascular repair of thoracic aorta remains significant. Patients with a history of MI had a higher perioperative cardiac event rate. Intraoperative predictors of perioperative cardiac events included blood loss, IV fluid requirement, and length of operation. Perioperative beta-blockade is important in endovascular thoracic surgery as a protection against postoperative cardiac events. Presented at the Annual Meeting of the Southern California Vascular Surgical Society, Carlsbad, CA, April 11-13, 2003.     

Dobutamine stress echocardiography as a predictor of cardiac events associated with aortic surgery.

Two-dimensional echocardiography can detect regional wall motion abnormalities resulting from myocardial ischemia produced by dobutamine infusion. In 60 patients undergoing elective aortic surgery (27 with aneurysms, 33 with occlusive disease), we evaluated the ability of dobutamine stress echocardiography to predict perioperative cardiac events. Echo images were obtained at rest and during incremental dobutamine infusion to a peak dose of 50 micrograms/kg/min, unless another test end point was reached (angina, heart rate greater than or equal to 85% of age-predicted maximum, significant ST segment depression, or new stress-induced wall motion abnormalities). Dobutamine stress echocardiography results were stratified as follows: group I, no wall motion abnormalities; group II, resting wall motion abnormalities unchanged with stress; group III, stress-induced worsening of resting wall motion abnormalities; group IV, new-onset wall motion abnormalities with stress. Twelve cardiac events occurred within the first 30 postoperative days: three cardiac deaths (5%), six nonfatal myocardial infarctions (10%), two patients with unstable angina (3.3%), and one patient with asymptomatic elevation of creatine phosphokinase MB isoenzymes without electrocardiographic changes (1.7%). Eleven events occurred in the 38 patients with an abnormal dobutamine stress echocardiograph (groups II to IV); in contrast, only one of 22 patients with a normal dobutamine stress echocardiograph (group I) had a cardiac event. These event rates (29% vs 4.6%) differed significantly (p less than 0.025). Dobutamine stress echocardiography is a new, safe, rapid, relatively low cost, noninvasive, nonexercise cardiac stress test for risk stratification before major vascular surgery.     

Is coronary angiography necessary for vascular surgery patients who have positive results of dipyridamole thallium scans?

Purpose: Because dipyridamole thallium (DT) scanning is a useful predictor of perioperative cardiac events, a positive result of a DT scan is frequently the basis for performing more invasive cardiac evaluation and for consideration for performing coronary revascularization procedures before performing peripheral vascular surgery. The rationale for this approach has been that the treatment of anatomically significant coronary artery disease would lower the risk of performing a subsequent vascular operation. However, the benefit of performing aggressive diagnostic and therapeutic cardiac procedures in such patients remains unproved. To examine this issue, data from patients who underwent coronary angiography because of thallium redistribution were compared with data from matched control subjects who underwent peripheral vascular operations without further cardiac evaluation.Methods: The medical records of 70 consecutive patients who underwent coronary angiography because of the presence of two or more segments of redistribution on DT scan were reviewed and compared with 70 other patients matched with respect to age, gender, peripheral vascular operation, and number of segments of redistribution on DT scan who did not undergo additional cardiac evaluation.Results: DT scans were performed on 934 preoperative peripheral vascular surgery patients to help in the assessment of operative risk. Ischemic responses, defined as two or more segments of redistribution, were observed in 297. Of these, 70 underwent cardiac catheterization and 25 underwent coronary revascularization procedures. Adverse outcomes affected 46% of the coronary angiography group and 44% of the control group (p = NS). Patients who underwent coronary angiography and were considered for myocardial revascularization had fewer cardiac events with a subsequent vascular operation than did the control subjects. However, any possible benefit from invasive cardiac evaluation was offset by the three deaths and two myocardial infarctions (MIs) that complicated the cardiac evaluation. There was no significant difference between the angiography group and the matched control subjects with respect to perioperative nonfatal MI (13% vs 9%), fatal MI (4% vs 3%), late nonfatal MI (16% vs 19%), or late cardiac death (10% vs 13%). In long-term follow-up, MIs occurred later in patients who underwent coronary angiography than the control subjects (p = 0.049), but this difference was not associated with an improvement in the overall survival rate.Conclusions: The risks of extended cardiac evaluation and treatment did not produce any improvement in either the perioperative or the long-term survival rate. For most vascular surgery patients who have a positive result of a DT scan, coronary angiography does not provide any additional useful information. (J Vasc Surg 1997;25:975-83.)     

Role of coronary angiography and coronary artery bypass surgery prior to abdominal aortic aneurysmectomy

It is well recognized that patients with abdominal aortic aneurysms have a high incidence of coronary artery disease, and that the major cause of death in patients undergoing aneurysmectomy has been acute myocardial infarction. In order to assess the incidence of significant coronary artery disease, cardiac catheterization was performed on 42 consecutive patients with abdominal aortic aneurysms. Thirty-six patients (85.7%) had significant anatomic coronary artery disease. Interestingly, all 8 patients with ejection fractions of less than 50% had triple vessel disease or left main disease, and 12 of 34 patients with ejection fractions greater than or equal to 50% had triple vessel disease or left main disease. Of the 30 patients who were NYHA Class I or Class II, 14 (46.7%) had triple vessel disease or left main disease. All 20 patients with triple vessel disease or left main disease underwent myocardial revascularization 7 to 10 days prior to abdominal aneurysmectomy. No patients had a perioperative myocardial infarction either following coronary artery bypass surgery or abdominal aortic aneurysm resection, and there were no operative mortalities. Although this was not a randomized study, it would seem from these results that in selected patients, myocardial revascularization prior to abdominal aneurysmectomy can decrease the incidence of acute myocardial infarction and also decrease operative mortality. It is presently recommended that all symptomatic patients, patients with ejection fractions of less than 50%, and asymptomatic patients with ejection fractions of greater than or equal to 50% with positive exercise radionuclide angiography undergo cardiac catheterization prior to aneurysmectomy, and those patients with left main disease or severe coronary artery disease undergo myocardial revascularization prior to aneurysm resection.     

Cardiac risk assessment of asymptomatic patients by stress echocardiography before infrarenal aortic aneurysm surgery

AIM: Aggressive cardiac assessment before aortic abdominal aneurysm (AAA) surgery is indicated for patients with symptomatic coronary artery disease (CAD). Assessment of intermediate and moderate risk patients is still under debate. The purpose of the study was to prospectively evaluate the effectiveness of stress echocardiography (SE) in the detection of CAD in patients undergoing AAA surgery who have no symptoms and/or signs of CAD, but who have risk factors for it. METHODS: Patients with 1 or more risk factors for CAD underwent SE. All patients with positive SE underwent coronary arteriography, and, when indicated, treatment. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for SE by comparing results to coronary arteriography. Moreover, major perioperative cardiac events were recorded. RESULTS: Ninety-one patients with AAA and risk factors for CAD were studied. SE was positive in 9 cases, including 7 presenting critical CAD on the basis of coronary arteriography. One major cardiac event (1.1%), a nonfatal myocardial infarction, occurred in 1 patient with positive SE and non-critical, single-vessel CAD. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SE proved to be 100%, 98%, 78%, 100%, and 92%, respectively. CONCLUSIONS: Positive SE should be considered a valid method for testing high-risk patients for CAD. The low rate of major cardiac events in this series suggests that cardiac assessment by SE and selective coronary arteriography prior to AAA surgery is effective in asymptomatic patients with one or more risk factors.     

Cardiac risk in vascular surgery. The oral dipyridamole-thallium stress test

The value of the oral dipyridamole-thallium stress test in identifying patients at high risk of myocardial infarction after vascular procedures has not been documented. We studied prospectively 46 patients who underwent an oral dipyridamole-thallium stress test before undergoing vascular operations. Twenty patients (43%) had a positive test result, defined by a thallium defect with reperfusion, while 26 patients had a negative test result. Myocardial infarctions were documented postoperatively in 5 (25%) of 20 of the group with positive results and 1 (4%) of 26 of the group with negative results. Three of the six myocardial infarctions were clinical; all three were in the group with positive results. No correlation was identified between dipyridamole-thallium stress test results and clinical cardiac history. A positive dipyridamole-thallium stress test result is a more sensitive predictor of postoperative myocardial infarction than ejection fraction or history of coronary artery disease. The oral dipyridamole-thallium stress test is as useful as the intravenous test in this setting.     

The role of central haemodynamic monitoring in abdominal aortic surgery. A prospective randomised study

To test the hypothesis that central haemodynamic monitoring is not necessary in all patients undergoing abdominal aortic surgery, a prospective randomised study in 40 consecutive patients undergoing elective abdominal aortic surgery was carried out. Patients with unstable angina, recent myocardial infarction (less than or equal to 6 months), and left ventricular ejection fraction (LVEF) less than 0.50 were excluded. Twenty-one patients had perioperative central haemodynamic monitoring while 19 patients had central venous pressure monitoring alone. Parameters studied included, perioperative haemodynamics and fluid balance, perioperative cardiac drug administration, operation time and clamp time, postoperative renal function, incidence of postoperative ventilation and line complications, duration of hospital and ICU stay, and 30 day postoperative outcome. Results obtained were compared with a high risk group of patients (LVEF less than 0.50) undergoing similar surgery. Statistical analysis failed to show any difference in outcome for any variable measured in either low risk group. All serious postoperative cardiac complications occurred in patients with LVEF less than 0.50 (P less than 0.0001). These data suggest that patients with LVEF greater than or equal to 0.50 are at low risk of developing postoperative cardiac complications and can be successfully managed perioperatively without the added potential risks and costs of central haemodynamic monitoring.     

Predictors of perioperative beta-blockade use in vascular surgery: a mail survey of United States anesthesiologists

OBJECTIVES: It was hypothesized that anesthesiologists' decisions to provide perioperative beta-blockade during vascular surgery would be influenced more by physician factors than by those of their patients. DESIGN: Mail survey. SETTING: Case presentation. PARTICIPANTS: Four hundred thirty-nine anesthesiologists in the United States who responded to a survey. INTERVENTIONS: By using Microsoft Word Mail Merge (Microsoft, Redmond, WA), 6 factors in a hypothetical patient presenting for vascular surgery (sex, race, age, comorbidities, functional status, and magnitude of surgical stress) were randomly varied. MEASUREMENTS AND MAIN RESULTS: The response rate was 22%. Self-reported propensity to use beta-blockade was significantly increased among anesthesiologists who worked in New England, among those who worked in larger hospitals, or who had received fellowship training. Among healthy patients, beta-blockers were more likely to be used for older than younger patients. Among sicker patients, however, the reverse was true. Heart rate triggers for beta-blockade use were higher than heart rates associated with improved outcomes in pivotal beta-blocker trials. CONCLUSIONS: Preferences for perioperative beta-blockade use in vascular surgery patients are influenced by anesthesiologists' demographics as well as patient comorbidities or degree of surgical stress. This finding suggests that efforts to increase perioperative beta-blockade in high-risk vascular patients face significant barriers from some groups of clinicians.     

Preoperative cardiac risk management

Approximately 100 million people undergo noncardiac surgery annually worldwide. It is estimated that around 3% of patients undergoing noncardiac surgery experience a major adverse cardiac event. Although cardiac events, like myocardial infarction, are major cause of perioperative morbidity or mortality, its true incidence is difficult to assess. The risk of perioperative cardiac complications depends mainly on two conditions: (1) identified risk factors, and (2) the type of the surgical procedure. On that basis, different scoring systems have been developed in order to accurately assess the perioperative cardiac risk and to improve the patient management. Importantly, patients with estimated high risk should be tested preoperatively by non-invasive cardiac imaging modalities. According to test results, they can proceed directly to planed surgery with the use of cardioprotective drugs (beta-blockers, statins, aspirin), or to myocardial revascularization prior to non-cardiac surgery. In this review, we discuss the role of clinical cardiac risk factors, laboratory measurements, additional non-invasive cardiac testing, and consequent strategies in perioperative management of patients undergoing noncardiac surgery.