Guidelines for perioperative cardiac evaluation from the American College of Cardiology/American Heart Association task force are effective for stratifying cardiac risk before aortic surgery

Critical Appraisal of Cardiac Risk Stratification Before Elective Vascular Surgery

This study was undertaken to evaluate the efficacy of the cardiac risk stratification protocol proposed by the American College of Cardiology/American Heart Association (ACC/AHA) in predicting cardiac morbidity and mortality associated with elective, major arterial surgery. Cardiac risk stratification using ACC/AHA guidelines was done on 425 consecutive patients before 481 elective cerebrovascular (n=146), aortic/inflow (n=166), or infrainguinal (n=169) procedures at an academic Veterans Affairs Medical Center. Cardiac risk was stratified as low, intermediate, or high based on clinical risk factors, such as, Eagle criteria, history of cardiac intervention, patient functional status, results of noninvasive cardiac stress testing, and coronary angiography with coronary revascularization performed when appropriate. Outcomes (myocardial infarction, unstable angina, congestive heart failure, ventricular arrhythmia, cardiac death, and mortality) within 30 days of surgery were compared between the various risk stratification groups. Univariate and multivariate analyses were used to identify clinically useful prognostic variables from the preoperative cardiac evaluation algorithm. Overall mortality (1.7%), cardiac death (0.4%), and adverse cardiac event (4.8%) rates were low, but cardiac death and morbidity were increased (p<0.05) in high-risk stratified patients (3.4%, 11.9%) compared to intermediate (0%, 2.8%) and low (0%, 4.0%) cardiac risk groups. The presence of 3-vessel angiographic coronary artery occlusive disease was an independent predictor of cardiac morbidity, while inducible ischemia by cardiac stress imaging was not. Previous coronary revascularization was associated with increased mortality as was the development of a non-cardiac complication. Cardiac risk assessment identified 78 (18%) patients with indications for coronary angiography. Angiographic findings resulted in coronary artery intervention (9-angioplasty; 4-bypass grafting) in 13 (3%) patients who experienced no adverse cardiac events after the planned vascular surgery (15 procedures). Cardiac risk stratification using ACC/AHA guidelines can predict adverse cardiac events associated with elective vascular surgery; however, protocol modification by increased reliance on Eagle criteria and less use of cardiac stress testing can improve identification of the “highest risk” patients who may benefit from prophylactic coronary intervention.

American College of Cardiology/American Heart Association perioperative assessment guidelines for noncardiac surgery reduces cardiologic resource utilization preserving a favourable clinical outcome

OBJECTIVES

The American College of Cardiology (ACC) and the American Heart Association (AHA) provided perioperative evaluation and management guidelines for assessing cardiac risk in noncardiac surgery. Even if previously validated as safe and effective in risk stratification, there is often a gap between clinical practice and the recommendations of the ACC/AHA guidelines. We evaluated the impact of strict application of ACC/AHA guidelines for cardiac risk assessment of patients undergoing elective noncardiac vascular surgery in a consultant anaesthesiologist-led preoperative clinic.

METHODS

One hundred and sixty-four consecutive patients who underwent elective vascular surgery after ACC/AHA guidelines implementation (from September 2004 to May 2005) were enrolled in the study and compared with a historical group of 166 patients operated from April 2002 to September 2002. Preoperative resources utilization (cardiologic consultations, non-invasive diagnostic tests, coronary angiograms, coronary revascularizations) and clinical events [all-cause death, acute myocardial infarction (AMI) and acute myocardial ischaemia] occurring within 30 days after surgical procedure were compared.

RESULTS

Guidelines implementation reduced preoperative cardiologic consultations by 21% (P < 0.001) and preoperative non-invasive diagnostic testing by 11% (P = 0.01), and increased utilization of preoperative beta-blockers by 13% (P = 0.01). Preoperative coronary angiograms (2% versus 4%) and coronary revascularizations (3% versus 2%) and all-cause death (1% versus 2%), AMI (2% versus 1%) and acute myocardial ischaemia (4% versus 2%) during follow-up were similar in both groups.

CONCLUSIONS

Implementation of the ACC/AHA guidelines for cardiac risk assessment prior to noncardiac surgery in a consultant anaesthesiologist-led preoperative clinic reduced preoperative resources utilization, improved medical treatment and preserved a low rate of perioperative cardiac complications.

Economic aspects of an anesthesia preoperative evaluation clinic

Studies continue to demonstrate that preoperative evaluation clinics help to prepare patients for surgery in a manner that minimizes cost and optimizes outcomes. These clinics are becoming common in both teaching and community hospitals. Many full service preoperative assessment clinics utilize specially trained nurses who are under the direction of an anesthesiologist. These clinics are associated with favorable outcomes, dramatic decreases in preoperative testing, infrequent subspecialty consultation and shorter lengths of stay. The current literature is reviewed and organizational and clinical changes that improve efficiency and patient care are highlighted.

Myocardial infarction in major noncardiac surgery: Epidemiology, pathophysiology and prevention

The number of subjects undergoing major noncardiac surgery who are at risk for perioperative myocardial infarction (MI) is growing worldwide.

It has been estimated that 500,000 to 900,000 patients suffer major perioperative cardiovascular complications every year, with consequent heavy, long-term prognostic implications and costs.

It is well known that perioperative MIs don’t share the same pathophysiology as nonsurgical MIs but the relative role of the different, potential triggers has not been completely clarified.

Many aspects of the perioperative management, including risk-stratification and prophylactic or postoperative interventions have also not been completely defined.

Throughout recent years many resources have been invested to clarify these aspects and experts have developed indices and algorithm-based strategies to better assess the cardiac risk and to guide the perioperative management.

The scope of the present review is to discuss the main aspects of perioperative MI in noncardiac surgery, with particular regard to epidemiology, pathophysiology, preoperative risk stratification, prophylaxis and therapy.

ACC/AHA guidelines for preoperative cardiovascular evaluation for noncardiac surgery: a critical point of view

This review examines the issue of preoperative cardiac evaluation from a critical point of view, based on recent medical literature. We reviewed the history of that field and focused on the American College of Cardiology and American Heart Association guidelines, which are a cornerstone in the field of cardiac patients undergoing noncardiac surgery. These guidelines synthesized the data into a comprehensive format and established the concept of integrating the patient's risk with the surgical risk. Nevertheless, there are some weaknesses in the guidelines. We believe that a better understanding of the guideline limitations will allow an improved and more educated practice of its recommendations.

Clinician agreement with perioperative cardiovascular evaluation guidelines and clinical outcomes

The American College of Cardiology/American Heart Association (ACC/AHA) published guidelines for preoperative cardiac risk stratification in 1996. Although clinician practice may differ from the guidelines, it remains unclear whether deviation from these guidelines affects clinical outcomes. This study sought to determine if discordance between clinician practice and the ACC/AHA guidelines affects perioperative cardiac outcomes. Eight hundred twenty-three patients who underwent 864 consecutive preoperative evaluations performed from 1995 to 1997 at a tertiary care academic medical center were prospectively followed. Clinician recommendations for preoperative cardiac testing were compared with ACC/AHA guideline recommendations. Frequencies of perioperative cardiac complications were compared between concordant and discordant testing recommendations. There were 33 perioperative cardiac complications (3.8%). Overall, there was no difference in the frequency of complications when there was discordance with the ACC/AHA guidelines compared with concordance (4.1% vs 3.7%, p = 0.81). The ACC/AHA guidelines recommended cardiac testing for 236 patients (27.3%). Clinicians ordered testing in half of those cases (n = 112). There was a lower frequency of cardiac complications when clinicians did not perform testing as recommended by the ACC/AHA guidelines (3.2% vs 10.7%, p = 0.02). Conversely, clinicians ordered cardiac testing in 45 patients (7%) when not recommended by the guidelines. Patients in this group had a trend toward more cardiac complications (6.7% vs 2.4%, p = 0.09). In conclusion, the failure of clinicians to follow the ACC/AHA guidelines when perioperative testing was recommended did not result in a higher frequency of cardiac complications.

A personal experience with factors influencing survival after elective open repair of infrarenal aortic aneurysms

OBJECTIVE

To investigate risk factors that influence survival after open abdominal aortic aneurysm (AAA) repair in all elective patients treated by a single surgeon at a tertiary referral center.

METHODS

The series includes 855 asymptomatic infrarenal AAAs in 732 men (86%) and 123 women with median ages of 69 and 71 years, respectively. Noninvasive myocardial imaging (n = 325), coronary arteriography (n = 418), or both were performed before surgery in 687 patients (80%), and 100 patients (15%) underwent preliminary coronary artery bypass grafting (n = 78) or percutaneous transluminal coronary angioplasty (n = 22) before their AAA procedures. Survival was assessed by using logistic regression analysis, proportional hazards models, and Kaplan-Meier estimations.

RESULTS

The operative mortality rate was 2.5%, ranging only from 1.8% to 2.8% since 1980. Late survival rates (70% at 5 years, 36% at 10 years, and 16% at 15 years) also remained remarkably similar during five arbitrary intervals comprising the entire study period. On multivariable analysis, overall mortality rates were adversely affected by older age (P < .001), increased creatinine levels (P < .001), straight aortic replacement grafting (P < .001), larger aneurysm diameter (P = .036), and chronic obstructive pulmonary disease (P = .012). The risk for any early or late death was favorably influenced by preliminary coronary artery bypass grafting or percutaneous transluminal coronary angioplasty (hazard ratio, 0.76; 95% confidence interval, 0.59-0.98; P = .035) even when a separate multivariable model was fit to accommodate nine other patients who also had preliminary coronary intervention but developed symptomatic AAAs before elective repair could be performed (hazard ratio, 0.78; 95% confidence interval, 0.61-0.99; P = .044).

CONCLUSIONS

Patient age and medical risk factors determine survival after open AAA repair to a very similar degree irrespective of the era when the operation is performed. In this particular series, preliminary coronary intervention seemed to benefit patients with severe coronary artery disease.

Perioperative cardiac events in patients undergoing noncardiac surgery: a review of the magnitude of the problem, the pathophysiology of the events and methods to estimate and communicate risk

This is the first of 2 articles evaluating cardiac events in patients undergoing noncardiac surgery. In this article, we review the magnitude of the problem, the pathophysiology of these events, approaches to risk assessment and communication of risk. The number of patients undergoing noncardiac surgery worldwide is growing, and annually 500,000 to 900,000 of these patients experience perioperative cardiac death, nonfatal myocardial infarction (MI) or nonfatal cardiac arrest. Although the evidence is limited, a substantial proportion of fatal perioperative MIs may not share the same pathophysiology as nonoperative MIs. A clearer understanding of the pathophysiology is needed to direct future research evaluating prophylactic, acute and long-term interventions. Researchers have developed tools to facilitate the estimation of perioperative cardiac risk. Studies suggest that the Lee index is the most accurate generic perioperative cardiac risk index. The limitations of the studies evaluating the ability of noninvasive cardiac tests to predict perioperative cardiac risk reveals considerable uncertainty as to the role of these popular tests. Similarly, there is uncertainty as to the predictive accuracy of the American College of Cardiology/American Heart Association algorithm for cardiac risk assessment. Patients are likely to benefit from improved estimation and communication of cardiac risk because the majority of noncardiac surgeries are elective and accurate risk estimation is important to allow informed patient and physician decision-making.

Vascular surgery patients: perioperative and long-term risk according to the ACC/AHA guidelines, the additive role of post-operative troponin elevation

AIMS

The objectives of this study are to evaluate the prognostic role of pre-operative stratification in patients undergoing elective major vascular surgery, the timing of adverse outcomes, and the predictive role of troponin (cTn).

METHODS AND RESULTS

Consecutive vascular surgery candidates (n=391) were prospectively stratified and treated according to the ACC/AHA guidelines. The patients were categorized into three groups: (1) with coronary revascularization in the past 5 years, (2) with intermediate clinical risk predictors, and (3) with minor or no clinical risk predictors. cTnI was measured post-operatively. By 18 months, 18.7% of subjects had experienced death or acute myocardial infarction (MI) (by the ACC/ESC criteria). The hazard ratio (HR) was 5.21 (95% CI=2.60-10.43; P<0.0001) in group 1 and 2.58 (95% CI=1.27-4.38; P=0.004) in group 2 when compared with group 3. Most events occurred within 30 days. Elevations of cTnI were associated with adverse outcomes even after multivariable adjustment at long-term (adjusted overall HR=4.73, 95% CI=2.92-7.65; P<0.0001) and at 30 days (adjusted HR=5.52, 95% CI=3.23-9.42; P<0.0001).

CONCLUSION

After pre-operative stratification, patients undergoing elective major vascular surgery remain at high risk of MI and death. Events occur mainly early after surgery. cTnI elevations are frequent and independently associated with increased risk. These findings suggest the need for a major re-evaluation of our approach to these patients.

Elective Open Operation for Abdominal Aortic Aneurysm in Octogenarians—Survival Analysis of 105 Patients

OBJECTIVES

To study early mortality and long-term survival of patients more than 80 years of age having elective open repair for abdominal aortic aneurysm (AAA).

DESIGN

Retrospective multicenter cohort study.

MATERIAL

One hundred and five patients, 23 women and 82 men, with a median age of 82 years, operated at three Norwegian hospitals during the period 1983-2002.

METHOD

Survival analyses were based on data from medical records and the Norwegian Registrar's Office of Births and Deaths. Expected survival was based on mortality rates of the general population, matched by age, sex, and calendar period. Relative survival was calculated as the ratio between the observed and the expected survival.

RESULTS

During the study period there has been a 10 fold increase in octogenarians treated with open operation for AAA. Early mortality (30-day) for the whole group of patients was 10.5% (95% confidence interval (95% CI) 5.3-18.0), and similar for both genders. The 5-year survival rate was 47% (95% CI 35.9-57.4), and not significantly different from that of a matched group in the general population. Patients aged 84 years or more had a median survival time of 35 months (95% CI 18.5-51.6).

CONCLUSION

The number of AAA operations in octogenarians has increased considerably during 20 years. Octogenarians operated electively for AAA has higher 30-day mortality as compared to younger patients. Their long-term survival appears similar to a matched control group. The benefit of surgery must be carefully considered against the perioperative risk, especially for the oldest octogenarians.

Coronary artery angioplasty for treatment of peri-operative myocardial ischaemia

Increasing numbers of elderly patients with severe co-existing medical diseases undergo major surgery. With these patients there is also an accompanying risk of age-related cardiovascular complications such as life-threatening myocardial ischaemia. We present a patient who suffered a myocardial infarction after a hemicolectomy and suffered a cardiac arrest in the recovery room. The therapeutic options available (e.g. coronary artery bypass grafting, acute percutaneous coronary angioplasty and peri-operative thrombolysis) are discussed and the successful management of the case by coronary angioplasty and stent implantation is described.

Strategies in the high-risk cardiac patient undergoing non-cardiac surgery

The risk of perioperative myocardial infarction or cardiac death in patients undergoing non-cardiac surgery may be estimated by clinical risk factor analysis and by myocardial stress testing. While stress testing modalities accurately delineate reversible myocardial ischaemia, their positive predictive value is low, and it is not clear whether their implementation improves outcome when compared to risk stratification alone. Similarly, it remains to be shown that preoperative coronary revascularization is an effective strategy in reducing perioperative risk. Recent reports indicate that surgery undertaken in the first weeks after percutaneous coronary interventions may be associated with a significantly increased rate of major complications. Administration of beta-blockers and alpha2-adrenergic agonists to high-risk patients reduces surgical morbidity and mortality, and the benefits observed with beta-blockers may extend long after the operative period. In high-risk patients undergoing major surgery, pulmonary artery catheter-guided haemodynamic optimization has not been associated with better outcomes, whereas use of regional anesthetic techniques decreases the incidence of postoperative pulmonary, but not cardiac, complications.

Long-term survival after vascular surgery: Specific influence of cardiac factors and implications for preoperative evaluation

OBJECTIVE

We sought to identify specific determinants of long-term cardiac events and survival in patients undergoing major arterial operations after preoperative cardiac risk stratification by American College of Cardiology/American Heart Association guidelines. A secondary goal was to define the potential long-term protective effect of previous coronary revascularization (coronary artery bypass grafting [CABG] or percutaneous coronary intervention [PCI]) in patients with vascular disease.

METHODS

Four hundred fifty-nine patients underwent risk stratification (high, intermediate, low) before 534 consecutive elective or urgent (<24 hours after presentation) open cerebrovascular, aortic, or lower limb reconstruction procedures between August 1996 and January 2000. Long-term follow-up (mean, 56 +/- 14 months) was possible in 97% of patients. The Kaplan-Meier method was used for survival data. Long-term prognostic variables were identified with the multivariate Cox proportional hazards model and contingency table analysis censoring early (<30 days) perioperative deaths.

RESULTS

While 5-year survival was 72% for the overall cohort, cardiac causes accounted for only 24% of all deaths, and new cardiac events (myocardial infarction, congestive heart failure, arrhythmia, unstable angina, new coronary angiography, new CABG or PCI, cardiac death) affected only 4.6% of patients per year during follow-up. High cardiac risk stratification level (hazards ratio [HR], 2.2, 95% confidence interval [CI], 1.4-3.4), adverse perioperative cardiac events (myocardial infarction, congestive heart failure, ventricular arrhythmia; HR, 2.2; 95% CI, 1.2-4.1), and age (HR, 0.33; 95% CI, 0.2-0.6) were independently prognostic for latemortality. Preoperative cardiac risk levels also correlated with new cardiac event rates ( P < .01) and late cardiac mortality ( P = .02). Modestly improved survival in patients who had undergone CABG or PCI less than 5 years before vascular operations compared with those who had undergone revascularization 5 or more years previously and those at high risk without previous coronary intervention (73% vs 58% vs 62% 5-year survival; P = .02) could be demonstrated with univariate testing, but not with multivariate analysis. Type of operation, urgency, noncardiac complications, and presence of diabetes did not affect long-term survival.

CONCLUSION

Despite cardiac events being a less common cause of late mortality after vascular surgery, perioperative cardiac factors (age, preoperative risk level, early cardiac complications) are the primary determinants of patient longevity. Patients undergoing more recent (<5 years) CABG or PCI before vascular surgery do not have an obvious survival advantage compared with patients at high cardiac risk without previous coronary interventions.

Routine Measurement of Radioisotope Left Ventricular Ejection Fraction Prior to Vascular Surgery: Is it Worthwhile?

OBJECTIVE

To determine whether estimation of left ventricular (LV) ejection fraction (EF) by means of multiple gated acquisition (MUGA) scanning could reliably stratify cardiac risk prior to elective major vascular surgery.

METHODS

A review of the English-language literature.

RESULTS AND CONCLUSIONS

Twenty-two studies enrolling a total of 3096 patients were identified from 1984 to date. Selection bias, blinding of the results, different cut-off limits, and several retrospective studies were some of the problems preventing a comprehensive analysis. The resting LVEF was not found to be a consistent predictor of perioperative ischaemic cardiac events. In the perioperative phase, poor LV function was, mainly, predictive of congestive heart failure, and, in the long-term, of cardiac outcome. The presence of myocardial wall motion abnormalities was also associated with both a higher chance of postoperative cardiac complications and a worse long-term cardiac outcome. Although measurements of LV function seem to play a key role in defining a patient's long-term prognosis, the value of routinely measuring LVEF preoperatively is limited and, therefore, MUGA scanning cannot be recommended as a general screening test. Despite this, it has been widely used for cardiac risk assessment in vascular surgery, and only recently its popularity has started declining. Other tests, such as stress-echocardiography and myocardial perfusion imaging, used selectively in moderate-risk patients can refine prediction of cardiac risk. In the future, gated stress myocardial perfusion scintigraphy, perhaps combined with ANP/BNP plasma level determination, may become a first choice test in preoperative cardiac risk assessment.

Low utility of dobutamine stress echocardiograms in the preoperative evaluation of patients scheduled for noncardiac surgery

In this study, we examined the utility of preoperative dobutamine stress echocardiograms (DSE) obtained for 85 patients in accordance with guidelines published by the American College of Cardiology (ACC) and the American Heart Association (AHA). The medical record of each patient was reviewed to identify the clinical criteria that indicated the need for a DSE, the DSE results, therapeutic interventions rendered as a result of the DSE, and any perioperative cardiac morbidity. The DSE was positive for inducible ischemia in 4 patients (4.7%), negative in 74 (87.1%), and nondiagnostic in 7 (8.2%). DSEs that were obtained for 48 patients because of a history of diabetes mellitus, mild angina, or "minor clinical predictors" produced only negative results. Of the four patients with positive DSE results, three underwent coronary angiography, and one of those three underwent bypass grafting before surgery. An additional 29 patients received a preoperative DSE but were excluded from the study because the criteria for ordering the DSE did not meet the ACC/AHA guidelines. No patient had any perioperative morbidity related to myocardial ischemia. The total patient charge for the 85 DSEs obtained at our institution was US$104,635. Use of the ACC/AHA guidelines for preoperative DSEs does not appear to be cost-effective. However, the current algorithm could be significantly improved by altering the criteria for obtaining preoperative DSEs.

IMPLICATIONS

This study was a retrospective review of 85 patient charts that found a low cost-effectiveness of using American College of Cardiology/American Heart Association guidelines for obtaining preoperative dobutamine stress echocardiograms. Suggested modifications of these guidelines should improve their specificity with no loss in sensitivity.

Prediction of cardiac risk before abdominal aortic reconstruction: comparison of a revised Goldman Cardiac Risk Index and radioisotope ejection fraction

BACKGROUND

A revised Goldman Cardiac Risk Index has been suggested to identify patients at higher risk for cardiac complications in patients who undergo major noncardiac surgery. The aim of this study was to test the usefulness of this model in an independent series of patients who underwent abdominal aortic surgery and to compare the index with the multiple gated acquisition (MUGA) scan in the prediction of cardiac complications.

METHODS

We studied 77 patients who underwent MUGA scan before elective abdominal aortic reconstruction. The revised index was calculated for each patient after recording the following five risk factors: history of ischemic heart disease, congestive heart failure, cerebrovascular disease, insulin-dependent diabetes, and creatinine level more than 2 mg/dL. Technetium-99m MUGA scan provided information about the resting left ventricular ejection fraction (LVEF) and the presence of regional wall motion abnormalities.

RESULTS

Fourteen patients (18%) had cardiac complications develop. The index proved to be a satisfactory predictor of postoperative cardiac events (P =.008), and an abnormal LVEF failed to do so (P =.1). The presence of wall abnormalities, with or without an abnormal LVEF, predicted cardiac complications (P =.004 and P =.006). Patients with a higher index score showed a tendency to have a lower LVEF (Spearman rank correlation, r = -0.43; P <.001). Wall abnormalities, with or without an abnormal LVEF, were more frequent in patients with higher scores (P =.03 and P =.009). Combining the index with the LVEF or the wall abnormalities or both could further stratify the cardiac risk (P =.004, P =.0003 and P =.0006, with chi(2) test for trend).

CONCLUSION

For those patients who undergo elective abdominal aortic surgery, the revised Goldman Cardiac Risk Index is a simple method of evaluating cardiac risk with minimum resource implications. MUGA scan can offer additional stratification in patients judged with the index to be at high risk.

Protocols and guidelines in critical care: development and implementation

Variation in clinical management has been associated with suboptimal outcomes and increased costs. Guidelines, protocols, and clinical pathways have evolved as a strategy to standardize care, principally by limiting variation, thereby reducing complications, decreasing length of stay and improving outcomes. However, the nature of critical care makes it difficult to conduct blinded, randomized, and controlled clinical trials, the specific type of science required for evidenced-based medicine and guideline development. Areas in which ICU-based guidelines have been successful include, among others, sedation and neuromuscular blockade use, ventilator management, antibiotic selection, and vascular surgical interventions.

Cardiac risk stratification for postmyocardial infarction dental patients

Traditional dental management guidelines of myocardial infarction survivors mandate a 6-month waiting period before elective treatment can be considered. Technological advances in cardiac disease diagnosis, management, and revascularization treatment may make this older mandatory 6-month waiting period obsolete. The purposes of this literature review are to provide an overview of the historical development of cardiac risk stratification and discuss current developments and guidelines in cardiac risk assessment. We hope that this review and update will stimulate the development of updated dental guidelines for treating the cardiac patient.