Relative effectiveness of four preoperative tests for predicting adverse cardiac outcomes after vascular surgery: a meta-analysis

Pre-operative stress testing in the evaluation of patients undergoing non-cardiac surgery: A systematic review and meta-analysis

Background

Pre-operative stress testing is widely used to evaluate patients for non-cardiac surgeries. However, its value in predicting peri-operative mortality is uncertain. The objective of this study is to assess the type and quality of available evidence in a comprehensive and statistically rigorous evaluation regarding the effectiveness of pre-operative stress testing in reducing 30-day post -operative mortality following non -cardiac surgery.

Methods

The databases of MEDLINE, EMBASE, and CENTRAL databases (from inception to January 27, 2016) were searched for all studies in English. We included studies with pre-operative stress testing prior to 10 different non-cardiac surgery among adults and excluded studies with sample size<15. The data on study characteristics, methodology and outcomes were extracted independently by two observers and checked by two other observers. The primary outcome was 30-day mortality. We performed random effects meta-analysis to estimate relative risk (RR) and 95% confidence intervals (95% CI) in two-group comparison and pooled the rates for stress test alone. Heterogeneity was assessed using I² and methodological quality of studies using Newcastle-Ottawa Quality Assessment Scale. The predefined protocol was registered in PROSPERO #CRD42016049212.

Results

From 1807 abstracts, 79 studies were eligible (297,534 patients): 40 had information on 30-day mortality, of which 6 studies compared stress test versus no stress test. The risk of 30-day mortality was not significant in the comparison of stress testing versus none (RR: 0.79, 95% CI = 0.35–1.80) along with weak evidence for heterogeneity. For the studies that evaluated stress testing without a comparison group, the pooled rates are 1.98% (95% CI = 1.25–2.85) with a high heterogeneity. There was evidence of potential publication bias and small study effects.

Conclusions

Despite substantial interest and research over the past 40 years to predict 30-day mortality risk among patients undergoing non-cardiac surgery, the current body of evidence is insufficient to derive a definitive conclusion as to whether stress testing leads to reduced peri-operative mortality.

Preoperative Assessment of the Patient with Cardiac Disease Undergoing Noncardiac Surgery

The American College of Cardiology/American Heart Association has published Guidelines on Perioperative Evaluation. Preoperative evaluation should focus on identifying patients with symptomatic and asymptomatic coronary artery disease. The guidelines advocate using the American College of Surgeons National Surgical Quality Improvement Project Risk Index to determine perioperative risk. Diagnostic testing should be reserved for those at increased risk with poor exercise capacity. Indications for coronary interventions are the same in the perioperative period as in the nonoperative setting. In patients with a prior coronary stent, optimal antiplatelet therapy and timing of elective noncardiac surgery is evolving.

Prognostic value of cardiac tests in potential kidney transplant recipients: a systematic review

BACKGROUND

Whether abnormal myocardial perfusion scintigraphy (MPS), dobutamine stress echocardiography (DSE) or coronary angiography, performed during preoperative evaluation for potential kidney transplant recipients, predicts future cardiovascular morbidity is unclear. We assessed test performance for predicting all-cause mortality, cardiovascular mortality and major adverse cardiac events (MACE).

METHODS

We searched MEDLINE and EMBASE (to February 2014), appraised studies, and calculated risk differences and relative risk ratios (RRR) with 95% confidence intervals (95% CI) using random effects meta-analysis.

RESULTS

Fifty-two studies (7401 participants) contributed data to the meta-analysis. Among the different tests, similar numbers of patients experienced MACE after an abnormal test result compared with a normal result (risk difference: MPS 20 per 100 patients tested [95% CI, 0.11-0.29], DSE 24 [95% CI, 0.10-0.38], and coronary angiography 20 [95% CI, 0.08-0.32; P = 0.91]). Although there was some evidence that coronary angiography was better at predicting all-cause mortality than MPS (RRR, 0.69; 95% CI, 0.49-0.96; P = 0.03) and DSE (RRR, 0.72; 95% CI, 0.50-1.02; P = 0.06), noninvasive tests were as good as coronary angiography at predicting cardiovascular mortality (RRR, MPS, 0.89; 95% CI, 0.38-2.10; P = 0.78; DSE, 1.09; 95% CI, 0.12-10.05; P = 0.93), and MACE (RRR: MPS, 1.09; 95% CI, 0.64-1.86; P = 0.74; DSE, 1.56; 95% CI, 0.71-3.45; P = 0.25).

CONCLUSIONS

Noninvasive tests are as good as coronary angiography at predicting future adverse cardiovascular events in advanced chronic kidney disease. However, a substantial number of people with negative test results go on to experience adverse cardiac events.

Anesthesiologists' preferences for preoperative cardiac evaluation before vascular surgery: results of a mail survey

STUDY OBJECTIVE

To investigate whether anesthesiologists' decisions to request preoperative cardiac evaluation (cardiologist consultation, echocardiography, and cardiac stress testing) before vascular surgery were influenced by patient comorbidity and magnitude of surgery; and to explore whether factors unrelated to the American College of Cardiology/American Heart Association (ACC/AHA) guidelines influence these decisions.

DESIGN

Survey instrument.

SETTING

University medical center.

SUBJECTS

2,000 U.S. anesthesiologists who were mailed a survey.

MEASUREMENTS

Six factors in a hypothetical patient presenting for vascular surgery [gender, race (white vs. black), age (65 yrs vs. 85 yrs), comorbidities (sick vs. healthy), functional status, and magnitude of surgical stress] were evaluated. Respondents were asked about their demographics, practice patterns, and how they would manage the hypothetical patient.

MAIN RESULTS

Of 2,000 mailed surveys, 439 U.S. anesthesiologists responded (22%). Multivariate ordinal logistic regression analysis showed that anesthesiologists were more likely to recommend preoperative cardiology consultation for patients with more comorbidities [odds ratio = 5.53; 95% confidence interval (CI) = 3.76, 8.15], for those with poorer functional status (odds ratio = 1.45; 95% CI = 1.02, 2.07), for those undergoing a more significant surgery (odds ratio = 1.61; 95% CI = 1.13, 2.30), as the clinicians' estimated risk of perioperative myocardial infarction increased (P < 0.001), or if they only infrequently anesthetized patients such as the one described in the scenario (P = 0.05). They also would request a preoperative echocardiogram for patients with more comorbidities (odds ratio = 2.58; 95% CI = 1.80, 3.68) and for those undergoing a more significant surgery (odds ratio = 1.59; 95% CI = 1.12, 2.25). A preoperative stress test was recommended for patients with more comorbidities (odds ratio = 3.01; 95% CI = 2.06, 4.38) and for those with a more significant surgery (odds ratio = 1.74; 95% CI = 1.15, 2.63). Other factors associated with request for a preoperative stress test were female gender of the anesthesiologist (odds ratio = 1.79; 95% CI = 1.11, 2.87), those with less experience with such patients (P = 0.05), and those from New England (odds ratio = 2.16; 95% CI = 1.01, 4.62).

CONCLUSIONS

Anesthesiologists' preferences for preoperative cardiac evaluation are generally consistent with evidence-based and expert-based AHA/ACC guidelines. However, other physician factors (ie, gender, years in practice, and familiarity with the surgical procedure) also influenced these decisions.

Screening value of N-terminal pro-B-type natriuretic peptide as a predictor of perioperative cardiac events after noncardiac surgery

Preoperative cardiac risk assessment is the cornerstone of rationale perioperative management that guides invasive surgical interventions. In addition to clinical risk factors, a simple screening biomarker would be useful for identifying those surgical patients who might benefit from additional cardiac testing or therapeutic interventions. Preoperative plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) are predictors of cardiac events after noncardiac surgery. NT–proBNP is synthesized in the ventricular myocardium in response to ventricular wall stress. To further increase the diagnostic accuracy of NT-proBNP for preoperative screening, it is important to identify confounding factors that influence NT-proBNP levels and their interaction with identifying risks for adverse cardiac events. Moreover, until now the available data from previous studies has been unable to consistently recognize the optimal discriminatory threshold for NT-proBNP. Currently, the ongoing DECREASE-VI study is conducted to evaluate whether current preoperative risk stratification can be improved by incorporating NT-proBNP measurements.

Intense cardiac troponin surveillance for long-term benefits is cost-effective in patients undergoing open abdominal aortic surgery: a decision analysis model

BACKGROUND

Strategies to limit adverse cardiac events after vascular surgery continue to evolve. Early recognition and treatment of myocardial ischemia may be a key to improving postoperative survival rates. Cardiac troponin I (cTnI) screening is an effective means of surveillance for postoperative myocardial ischemic injury and has long-term prognostic value.

METHODS

We designed a Markov-based decision analysis model to determine the cost-effectiveness of routine surveillance with cTnI on postoperative Days 0, 1, 2, and 3, with an aim to institute tight heart rate control (60-65 bpm) with close monitoring and coronary care in the intensive care unit for 5 days in patients with cTnI >1.5 ng/mL. The key input variables obtained from published literature were as follows: probability of myocardial infarction, 0.049; cost of cTnI surveillance, $357; cost and efficacy of interventions, $13,145 and 0.55, respectively. The time horizon was lifetime and the target population being individuals aged 65 yr (median) undergoing elective open abdominal aortic surgery. The perspective for analysis was third-party payer.

RESULTS

The incremental cost-effectiveness ratio for cTnI surveillance was $12,641 per quality-adjusted life year compared with standard care without cTnI surveillance. During one-way sensitivity analysis, probability of myocardial infarction and efficacy of interventions were found to influence the cost-effectiveness. Multivariate sensitivity analysis with second-order Monte Carlo simulation revealed that cTnI surveillance was favored in 90.75% of simulations at a commonly used threshold of $50,000 per quality-adjusted life year.

CONCLUSIONS

In patients presenting for elective open abdominal aortic surgery, intensive surveillance with cTnI and early institution of aggressive beta-blockade is cost-effective.

Perioperative medical management of ischemic heart disease in patients undergoing noncardiac surgery

PURPOSE OF REVIEW

Cardiovascular disease is the leading cause of death after anesthesia and surgery. The preoperative identification of patients with underlying coronary artery disease is important to initiate appropriate treatment strategies in order to reduce the risk of perioperative complications. The current review will discuss new insights in the field of perioperative medicine that can be applied to clinical practice or stimulate further investigation.

RECENT FINDINGS

Recent findings in the past year have developed preoperative risk stratification in terms of simplicity, safety, accuracy and cost-effectiveness. Natriuretic peptides have been demonstrated to be promising new preoperative risk markers. Although recommended in high-risk patients, noninvasive cardiac stress testing may be safely omitted in patients at intermediate risk. The antiischemic properties of beta-blockers have been well described. In clinical practice, however, adequate beta-blocker dosage, tight perioperative heart rate control and continuation of beta-blockers after surgery may also be important factors. Statins have emerged as promising drugs with perioperative cardioprotective properties. Before recommending routine administration of statin therapy, however, more clinical trials are needed.

SUMMARY

New perceptions in perioperative medical management and novel developments in surgical and anesthesiology techniques continue to improve the cardiovascular outcome of patents undergoing major noncardiac surgery.

Vascular surgery critical care: perioperative cardiac optimization to improve survival

OBJECTIVE

To review the literature on perioperative cardiac management of patients who are scheduled to undergo vascular surgery.

DATA SOURCE

MEDLINE- and PubMed-based review of literature published from 1965 to 2005.

CONCLUSIONS

Perioperative cardiac events (myocardial infarction, heart failure) remain the leading cause of morbidity and mortality in vascular surgery patients. Existing guidelines allow physicians to cost-effectively streamline preoperative cardiac risk assessment and stratification. Perioperative optimization of volume status and cardiac function and the routine use of perioperative beta-blockers can significantly improve outcomes after major vascular surgery. Perioperative addition of statins to beta-blockers in high-risk patients undergoing vascular surgery merits further evaluation. Preoperative coronary revascularization should be restricted to patients with unstable cardiac symptoms.

Perioperative glucose control in the diabetic or nondiabetic patient

Patients with diabetes are more likely to undergo surgery than nondiabetics, and maintaining glycemic control in subjects with diabetes can be challenging during the perioperative period. Surgery in diabetic patients is associated with longer hospital stay, higher health care resource utilization, and greater perioperative mortality. In addition, several observational and interventional studies have indicated that hyperglycemia is associated with adverse clinical outcomes in surgical and critically ill patients. This paper reviews the pathophysiology of hyperglycemia during trauma and surgical stress and will provide practical recommendations for the preoperative, intraoperative, and postoperative care of diabetic patients.

Risk Scoring in Perioperative and Surgical Intensive Care Patients: A Review

PURPOSE

Assessing the risk and predicting the outcome of surgery, trauma, and surgical intensive care is an important aspect of perioperative practice. There have been attempts to devise and validate many scoring systems to predict the prognosis of patients having a similar severity of illness. This article reviews some of the commonly used systems with respect to their development, strengths, and limitations.

SOURCES

Published literature describing risk assessment scores and physiologic scoring systems for preoperative assessment, trauma, and surgical intensive care patients.

PRINCIPAL FINDINGS

Risk scores used in preoperative evaluation assist the clinician in optimizing the patient before, during, and after surgery. Scoring systems applied in intensive care units are useful as guidelines rather than accurate predictors of prognosis for individual patient. Many models are used for audit purposes, and some are used as performance measures and quality indicators of a unit; however, both utilities are controversial because of poor adjustment of these systems to case-mixtures.

CONCLUSIONS

Risk assessment scores may assist in the perioperative risk evaluation with respect to organ systems. Prognostication of critically ill patients belonging to a category of illness may be done using physiological scoring systems taking into account the difference in the case-mix of the particular unit.

Anesthésie et réanimation pour chirurgie réglée de l'anévrisme de l'aorte abdominale

OBJECTIVES

Patient scheduled for infrarenal abdominal aortic aneurysm surgery carries a high risk of cardiac or respiratory comorbidity. To outline the perioperative management for these patients.

METHODS

Review of the literature using MesH Terms "abdominal aortic aneurysm", "anesthesia", "analgesia" "critical care" and/or "surgery" in Medline database.

RESULTS

Cardiac preoperative evaluation and management have recently been reviewed. Intermediate and high-risk patients should undergo non-invasive cardiac testing to decide between a preoperative medical strategy (using betablocker+/-statin and aspirin) and an interventional strategy (coronary angioplasty or cardiac surgery). Perioperative myocardial ischaemia should also be investigated by clinical, electrocardiographic and biologic monitoring such as plasmatic troponin Ic dosage. Specific score could also assess the respiratory failure risk preoperatively. Epidural analgesia decreases this risk. There is no evidence that a pharmacological treatment decreases the incidence of acute renal failure after aortic surgery. Endovascular repair is actually recommended for older, higher-risk patients or patients with a hostile abdomen or other technical factors that may complicate standard open repair.

A Meta-Analytic Comparison of Preoperative Stress Echocardiography and Nuclear Scintigraphy Imaging

In this meta-analysis we compared thallium imaging (TI) and stress echocardiography (SE) in patients at risk for myocardial infarction (MI) scheduled for elective noncardiac surgery. Two searches of published articles were used to identify relevant articles. We included all studies that stated the criteria for a positive test and detailed the frequency of postoperative MI and in-hospital death. Data were abstracted by two authors and captured preoperative patient characteristics, study design, blinding, and outcome adjudication. We defined a positive test as a test with a reversible defect and, where possible, quantified the size of the defects in each study. MI and/or death were the only postoperative outcomes of interest. We calculated the sensitivity, specificity, and likelihood ratio (LR) and, where possible, the Receiver Operating Characteristic (ROC) curve of a cardiac event in each study. The LR and ROC were combined by meta-analyses using the random effects model. Heterogeneity was assessed using the I2 test. The search revealed 68 studies of 10,049 patients. There were 25 SE studies and 50 TI studies. There were 7 studies with a direct comparison of the two methodologies. The quality of studies differed; routine screening for MI was used more frequently in SE studies (47.8% versus 21.2%; P = 0.008) and screening dictated treatment more often after TI (72.1%) than after SE (46.3%) (P = 0.027). The LR for SE was more indicative of a postoperative cardiac event than TI (LR, 4.09; 95% CI, 3.21-6.56 versus 1.83; 1.59-2.10; P = 0.001). This difference was attributable to fewer false-negative SEs. There was no difference in the cumulative ROC curves from qualitative studies (SE, 0.80; 95% CI, 0.76-.84 versus TI, 0.75; 95% CI, 0.70-081). Again, the LR for a negative SE was less (0.23; 95% CI, 0.17-0.32 versus 0.44; 95% CI, 0.36-0.54). A moderate-to-large defect, seen in 14% of patients, by either method predicts a postoperative cardiac event (LR, 8.35; 95% CI, 5.6-12.45). This meta-analysis possesses the statistical power to demonstrate that SE has better negative predicative characteristics than TI. A moderate-to-large perfusion defect by either SE or TI predicts postoperative MI and death. We conclude the SE is superior to TI in predicting postoperative cardiac events.

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.

Intraoperative management of aortic aneurysm surgery

Managing the anesthesia of patients undergoing open aortic surgical repair is a great challenge. The anesthesiologist's role in myocardial,renal, and neurologic protection is crucial to the patient's overall outcome.Each case presents different challenges, and there is no one right way to manage the patient intraoperatively.

Preoperative cardiac evaluation

Guidelines on perioperative cardiovascular evaluation for noncardiac surgery have been published. The integration of clinical risk factors, surgery-specific risk,and functional capacity should be used to determine the need for further diagnostic evaluation. The use of beta-adrenergic blockade in high-risk patients,particularly those with documented myocardium at risk undergoing vascular surgery, has been shown to reduce perioperative risk and may obviate the need for more invasive procedures. Coronary intervention should be reserved for those patients who warrant intervention independent of the noncardiac surgery.

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.

Cardiac scoring systems--what is their value?

Estimating the peri-operative risk of major adverse cardiac events is one of the functions of cardiac risk scoring systems. Fortunately, peri-operative cardiac complications are relatively infrequent in most patients. Clinical algorithms use sequential screening tests to detect patients most at risk of cardiac complications. However, because the sensitivity and specificity of the tests used are low, the predictive performance of the commonly-used cardiac screening tests may not be completely satisfactory. The purpose of this review is to describe measures of performance of cardiac screening tests and illustrate their potential benefits and weaknesses.

Cardiac complications after elective major vascular surgery

Cardiac complications are the major cause of perioperative and late mortality and morbidity in patients undergoing elective major vascular surgery. This review focuses on the pathophysiology of perioperative complications, risk assessment and risk reduction strategies, all related to cardiovascular disease. Patients without cardiac risk factors are considered to be at low risk and no additional evaluation for coronary artery disease is recommended; beta-adrenergic blockers may reduce perioperative cardiac events; patients with one or more risk factors represent an intermediate to high-risk population. beta-Adrenergic blockers should be prescribed to all patients and coronary revascularization should be reserved for patients who have a clearly defined need for revascularization independent of the need for vascular surgery.

The role of myocardial perfusion scanning, heart rate variability and D-dimers in predicting the risk of perioperative cardiac complications after peripheral vascular surgery

OBJECTIVES

To study the value of a number of proposed prognostic factors in prediction of the risk of perioperative cardiac events after vascular surgery.

DESIGN AND METHODS

Two hundred and ninety-seven patients undergoing peripheral vascular surgery were prospectively studied. Patients underwent preoperative 24 h ambulatory electrocardiography, measurement of haemostatic variables, myocardial assessment of perfusion by dipyridamole-thallium scintigraphy and radionuclide ventriculography. The primary endpoint was cardiac death or nonfatal myocardial infarction within 30 days of surgery. A combined endpoint included the primary endpoint plus occurrence of cardiac failure, unstable angina or serious arrhythmias.

RESULTS

The primary endpoint occurred in 21 (7%), and the combined endpoint in 41 (14%) of patients. On multivariate analysis, increased age, previous myocardial infarction, aortic surgery, impaired heart rate variability and a positive thallium scan were independent predictors of primary end-points. Preoperative atrial fibrillation and increased fibrin D-dimer were additional predictors of the combined endpoint. Construction of receiver-operator characteristic curves to examine the incremental value of predictive models showed that sensitivity and specificity of clinical data alone for primary endpoints was 71% and 72% respectively, while for the full model (incorporating heart rate variability and thallium data) this rose to 84% and 80% (p=0.0001).

CONCLUSIONS

Preliminary screening using clinical data has limited value in risk assessment prior to vascular surgery but preoperative heart rate variability, D-dimers and thallium scanning provide modest incremental predictive value.

Examining the evidence in anesthesia literature: a critical appraisal of systematic reviews

Systematic reviews are structured reviews that use scientific strategies to reduce bias in the collection, appraisal, and interpretation of relevant studies. We undertook a systematic review of published systematic reviews in perioperative medicine to summarize the areas currently covered by this type of literature, to evaluate the quality of systematic reviews in this field, and to assess some of the methodologic and reporting issues that are unique to systematic reviews. Computerized bibliographic databases, citation review, and hand searches were performed to identify eligible articles. Quality was assessed using the Overview Quality Assessment Questionnaire. Eight-two systematic reviews were found. Reviews in perioperative medicine tended to evaluate prophylactic or therapeutic interventions. No differences were seen in quality between reviews published in anesthesia and nonanesthesia journals. Nearly half of all systematic reviews had only minor or minimal flaws; however, methods can be improved with expanded search strategies, use of least two reviewers to assess each study, use of validated methods to evaluate quality, and assessment of potential sources of bias.

IMPLICATIONS

The quality of systematic reviews relating to perioperative medicine was examined systematically and found to be similar in quality to those in other specialties. Adoption of recently published criteria on writing and methods could further improve this type of literature.

Preoperative Evaluation of the Patient for Vascular Surgery in the "Real World"

Patients presenting for vascular surgery frequently have multiple coexisting diseases. To meet the goal of providing a safe anesthetic with optimum resource use, we must ex amine the impact of each of these conditions on the patient and how the data from a particular evaluation or test will impact our anesthetic plan. Existing guidelines may be valu able if adapted to institution-specific circumstances. Con sultants represent a relatively high-cost resource, which can be optimized when used with clear goals in sight. Finally, we may be able to modify our evaluation based on the antici pated procedure, as these patients are exposed to a range of potential hemodynamic stresses.

Preoperative cardiac risk assessment

Preoperative cardiac evaluation is aimed at evaluating the patient's current medical status, making recommendations concerning the risk of cardiac problems in the perioperative period, and providing a clinical risk profile that the patient, primary physician, consultants, anesthesiologist, and surgeon can use in making treatment decisions. Patients can be stratified on clinical grounds into low-, medium-, and high-risk categories. Use of these categories, along with consideration of the type and urgency of noncardiac surgery, allows for a reasonable approach to preoperative testing. In general, indications for cardiac testing and treatment are similar to the nonoperative setting, but their choice and timing is dependent on factors specific to the patient, the type of surgery, and the clinical situation. Use of invasive and noninvasive testing should be limited to situations in which the results of the tests will clearly affect patient management. Further research is necessary to define the most appropriate role of such testing, both in terms of efficacy and of cost-effectiveness. Cardiac intervention is rarely necessary to lower the risk of surgery, but noncardiac surgery often represents the first opportunity for a patient to receive an appropriate assessment of short- and long-term cardiac risk, and this should be taken into consideration in planning perioperative evaluation.

[Dobutamine echocardiography for the preoperative evaluation of patients for surgery of the abdominal aorta]

OBJECTIVE

The aim of the study was to assess the value of dobutamine echocardiography (DE) for detecting coronary artery disease (CAD) in patients scheduled for abdominal aortic surgery.

STUDY DESIGN

Preliminary prospective open study.

PATIENTS

Thirty-three consecutive patients due to undergo effective abdominal aortic surgery, assessed by preoperative DE.

METHODS

Previous myocardial infarction and atherosclerotic risk factors (RF) were noted. Incremental doses of dobutamine were administered in order to reach 85% of age-predicted maximal heart rate. The occurrence of regional wall motion abnormalities was considered as a positive test. In this case a coronary angiography was performed.

RESULTS

Four patients had a history of angina pectoris. DE was not interpretable in five patients. Among the patients without symptoms, 12 had three RF or more, 12 had less than three RF. In eight patients with a positive test, coronary angiography showed one or more significant main coronary artery stenoses. All patients with angina pectoris had a positive test. None of patients without symptoms and less than three RF had a positive test, one third of patients with no symptomatology but with three RF or more had a positive test (P < 0.05).

CONCLUSION

DE has the ability to identify patients with asymptomatic CAD. DE is recommended in patients with high probability of CAD, i.e. with three RF or more.

Preoperative cardiac evaluation of women for noncardiac surgery

Cardiac risk assessment is a crucial aspect of perioperative evaluation because it is estimated that 1 million people, regardless of gender, will have perioperative cardiac complications at a cost of 20 billion dollars. Unfortunately, establishment of optimal guidelines for selected patient subgroups, particularly women, are lacking. More prospective studies are needed to help evaluate the most cost-effective, yet accurate way to noninvasively assess the presence of coronary artery disease in women.

The utility of dobutamine echocardiography in preoperative evaluation for elective aortic surgery

BACKGROUND

Preoperative cardiac evaluations have been advocated prior to major vascular procedures to reduce the incidence of postoperative cardiac complications. This study was undertaken to evaluate the efficacy and predictive value of routine dobutamine echocardiography (DE) in the screening of patients undergoing elective aortic surgery.

METHODS

Dobutamine echocardiography was performed preoperatively on all patients having elective aortic procedures by our university surgical group from June 1995 to August 1996. The cardiac morbidity and mortality from this group were compared with that of a similar group undergoing elective aortic procedures from June 1993 to May 1995 with no dobutamine echocardiography (NDE).

RESULTS

Although there was no statistically significant difference in either overall mortality (4.4% in NDE vs. 2.3% in DE) or cardiac mortality (2.9% in NDE vs. 0% in DE) between the two groups, cardiac events occurred only in those patients with previous coronary artery disease. In addition, dobutamine echocardiography had a negative predictive value of 97%

CONCLUSIONS

Although routine screening is not necessary, selective screening of patients using dobutamine stress echocardiography is justified because of its high negative predictive value.

Outpatient echocardiography as a predictor of perioperative cardiac morbidity after peripheral vascular surgical procedures

PURPOSE

A variety of preoperative provocative tests have been used to define the risk of cardiac morbidity and mortality after peripheral vascular procedures, including dipyridamole myocardial scintigraphy and dobutamine stress echocardiography. Although highly sensitive, these tests are time-consuming and associated with significant expense. We investigated outpatient echocardiography as a less resource-intensive means of assessing cardiac risk with operation.

METHODS

Over a 2-year period 250 consecutive patients underwent outpatient transthoracic echocardiography before elective peripheral vascular operation was performed. The accuracy of the Goldman, Detsky, and the American Society of Anesthesiologists' Physical Status Classification clinical indexes of cardiac risk were assessed with regard to the development of cardiac complications such as unstable angina, myocardial infarction, life-threatening ventricular arrhythmias, severe congestive heart failure, and cardiogenic shock. The accuracy of echocardiographically determined left ventricular ejection fraction was determined at threshold values between 20% and 60%.

RESULTS

Perioperative cardiac events developed in 23 (9.2%) of the patients, and nine (3.6%) of the patients died as a result of these complications. Clinical indexes lacked sensitivity in the preoperative prediction of cardiac complications. Receiver operating curve analysis defined a left ventricular ejection fraction of less than 50% as an appropriate threshold for defining patients at high risk, with a sensitivity of 78% and a specificity of 81% in the identification of patients who had cardiac morbidity. The positive predictive value was 27%, and the negative predictive value was 97%. The economic impact of outpatient echocardiography was well below that of dipyridamole myocardial scintigraphy or dobutamine stress echocardiography.

CONCLUSIONS

Outpatient echocardiography appears to offer a cost-efficient compromise between clinical criteria alone and provocative cardiac testing such as dipyridamole myocardial scintigraphy and dobutamine stress echocardiography in the preoperative screening of patients undergoing peripheral vascular surgical procedures.