Guidelines for perioperative cardiovascular evaluation for noncardiac surgery. Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Perioperative Cardiovascular Evaluation for Noncardiac Surgery)

Attenuation correction for single photon emission computed tomography myocardial perfusion imaging

The specificity of cardiac single photon emission computed tomography (SPECT) perfusion imaging is significantly affected by internal photon absorption. Commonly referred to as anterior wall breast and inferior wall diaphragm attenuation artifacts, even when following characteristic patterns in women and men, the reduced activity produced can be difficult to differentiate from real perfusion defects. Unfortunately, wide variations in body habitus result in unpredictable variations in tissue attenuation and the specificity of uncorrected SPECT is unacceptably low in many laboratories. This manuscript reviews recent developments in attenuation correction methods for cardiac SPECT. Several commercial methods are now available, and although the initial success using these methods varied widely, as these methods have been improved successful clinical reports are appearing with increasing frequency. Recent developments have yielded more robust validated methods and significant clinical advantages have been achieved in the diagnostic evaluation of coronary heart disease (sensitivity as well as specificity) and myocardial viability. As these methods continue to mature, further advances should be anticipated.

[Anaesthesia and amiodarone-associated hyperthyroidism]

Amiodarone can induce severe hyperthyroidism that justifies its withdrawal and initiation of antithyroid drugs. Impossibility to stop amiodarone, failure to control hyperthyroidism and unfavourable evolution can lead to thyroidectomy. Cardiac manifestations, persistence of hyperthyroidism and interactions between amiodarone and anaesthetic or haemodynamic drugs may contraindicate anaesthesia. We report nine consecutive cases of amiodarone-associated hyperthyroidism that prompted us to perform thyroidectomy under general anaesthesia. The features and anaesthetic data of patients were noted. The antithyroid medical treatment failed in all patients. After thyroidectomy, evolution was favourable in all nine cases, without any intra or postoperative complication, in spite of the extent of hyperthyroidism and the severity of the associated cardiac problems. Despite potential high risks, thyroidectomy for amiodarone-induced hyperthyroidism does not seem to increase morbidity or mortality and allows a quick return to euthyroidism and reintroduction of amiodarone.

Preoperative assessment and management to prevent complications during high-risk vascular surgery

OBJECTIVE

Most patients requiring vascular surgical reconstruction are at high risk for major morbidity and mortality, with certain vascular procedures at particularly high risk for complications. Although numerous comorbid conditions are precisely the risk factors that determine outcome, we review particular factors for each surgery that may be optimized to alter outcome and minimize postoperative complications.

DESIGN

Literature review.

RESULTS

Certain aspects of care are common to all vascular surgery procedures, including thoracoabdominal aortic aneurysm repair, pararenal and ruptured abdominal aortic aneurysm repair, mesenteric and renal revascularization, and carotid endarterectomy. Some factors that are important include careful preoperative assessment and optimization of cardiac, pulmonary, and renal function and volume status. In addition, the use of experienced teams during and after the procedure, as well as clear and continuous communication between all surgical team members, may improve outcome. Particular attention to procedural details is also crucial to achieving excellent results.

CONCLUSIONS

Patients needing vascular surgery often possess management challenges that increase the risk of perioperative complications. Meticulous attention to details during all phases of care, including preoperative optimization as well as intraoperative procedural conduct and communication, helps achieve optimal results and thus minimize the risk of complications.

Assessment and management of patients with ischemic heart disease

OBJECTIVE

Review the perioperative management of patients who are scheduled for noncardiac surgery.

DATA SOURCE

Review of literature (PubMed, MEDLINE).

CONCLUSIONS

Patients with ischemic heart disease who undergo noncardiac surgery are at significant risk of perioperative cardiac morbidity and mortality. Recent joint guidelines from the American College of Cardiology and American Heart Association have significantly streamlined the preoperative evaluation processes. Augmented hemodynamic control with intensive perioperative pharmacologic therapy with beta-blockers and possibly alpha-2 agonist has been shown to improve perioperative cardiovascular outcomes. However, translating this information to clinical practice continues to be a challenge and requires a multi- disciplinary approach. A particular intraoperative anesthetic technique is unlikely to influence perioperative cardiac morbidity and mortality. Postoperative management with goals of decreasing hemodynamic stress is important in patients with ischemic heart disease. Diagnosis and management of perioperative myocardial infarction continues to be a challenge. However, use of cardiac specific biomarkers should improve the diagnostic process.

Cost efficiency of nuclear cardiology services in the modern health care environment

More than a decade of dramatic changes in US and global health care has affected the practice of and payment for nuclear cardiology services. The clear diagnostic and prognostic power of nuclear cardiology procedures to detect coronary artery disease and predict patient outcomes has resulted in the rapid growth of these procedures in clinical practice. This has focused the attention of public and private payers on the high use of medical resources required to carry out nuclear cardiology testing. Two recent, major multicenter trials, one in the United States and another in Europe, have demonstrated the cost effectiveness of stress myocardial perfusion imaging strategies compared with coronary angiography in patients with known or suspected coronary artery disease, across the spectrum of pretest risks and both sexes. These studies, and more extensive data from more than 10 years of decision analysis, have reinforced the value of nuclear cardiology in modern cardiovascular health care. Future challenges will include assurance of provider and laboratory quality in the burgeoning outpatient imaging centers across the country, and wider acceptance by payers and expert panels of the evidence supporting the cost effectiveness of nuclear cardiology in most clinical settings.

Preoperative assessment

Although anaesthetic and surgical procedures should be individualised for every patient, in practice many preoperative protocols and routines are used generally. In this article, we aim to emphasise: why preoperative assessment is important; how it should be done, and by whom; what can be expected; and the importance of test selection based on patients' needs and on scientific evidence of effectiveness. We outline the roles of preoperative medical assessment in otherwise healthy patients. Clinical history, preoperative questionnaires, physical examination, routine tests, individual risk-assessment, and fasting policies are investigated by review of published work. Cost of routine preoperative assessment, the anaesthetist's legal responsibility, and patients'views in the preoperative process are also considered. A thorough clinical preoperative assessment of the patient is more important than routine preoperative tests, which should be requested only when justified by clinical indications. Moreover, this practice eliminates unnecessary cost without compromising the safety and quality of care. Education and training of medical doctors should be more scientifically guided, emphasising the relevance of effectiveness, and cost-effectiveness in clinical decision-making and complemented by audit.

Guideline chaos: conflicting recommendations for preoperative cardiac assessment

The American College of Cardiology/American Heart Association (ACC/AHA) and the American College of Physicians (ACP) have disseminated guidelines to assess preoperative cardiac risks before noncardiac surgery. The objectives of this study were to determine if these guidelines differ in preoperative recommendations for a group of patients, and whether these recommendations differ from actual provider recommendations. In this retrospective cohort study, patient characteristics and physician recommendations were abstracted from electronic medical records of consecutive patients attending a Veteran Affairs medical preoperative evaluation clinic from January 1 to April 1, 1998. Patient characteristics were used to determine what preoperative cardiac testing should have been ordered if each guideline was followed. Possible recommendations included operation without testing (OWT), noninvasive stress testing (NST), cardiac catheterization (CC), or cancel or delay surgery (OTHER). Recommendations were compared using statistical tests for agreement. Of the 138 patients identified, most underwent moderate-risk surgeries. Recommendations for preoperative testing were discordant between guidelines for 17% of patients (kappa = 0.38). Guidelines never agreed on the need for NST. Extreme differences in recommendations (i.e., one recommends OWT, the other CC) occurred in 9 patients (7%). Physicians ordered NST more often (n = 27) than either guideline. In this subgroup of patients where providers ordered a NST, the 2 guidelines significantly differed (kappa = 0.26). When applied to real patients being evaluated for surgery, ACC/AHA and ACP guidelines significantly differed in recommendations for preoperative cardiac testing. Results have implications for implementation, management, and practitioner adherence to published guidelines.

Magnetic resonance imaging assessment of cardiac function

Measurements of left ventricular function at rest and during stress are useful for identifying myocardial ischemia, injury, and the risk of subsequent myocardial infarction. Without ionizing radiation or intravascular contrast administration, magnetic resonance imaging techniques can be used to acquire precise measurements of left ventricular function. This relatively new development may enhance a physician's ability to provide care to patients with cardiovascular disease.

Preoperative risk evaluation and perioperative management of patients with coronary artery disease

We have reviewed the methods of evaluating a patient's cardiac risk preoperatively using a careful history, physical examination, and EKG. Based on this information, various risk indices, guidelines, and algorithms can further assist the physician in deciding which patients can undergo surgery without further testing and which patients might benefit from further cardiac evaluation or medical therapy prior to surgery. The physician must keep in mind that a test should not be ordered if it is unlikely to alter the patient's management, and it is rarely necessary to perform a revascularization procedure with the sole purpose of getting a patient through surgery. Ongoing research is likely to lead to improvement in perioperative medical therapy.

Pharmacologic radionuclide myocardial perfusion imaging

Pharmacologic stress testing with myocardial perfusion imaging has enabled patients who cannot complete adequate exercise to undergo diagnostic and prognostic evaluation for coronary artery disease. Pharmacologic stress agents belong to two groups: vasodilators (such as adenosine and dipyridamole), and inotropes (such as dobutamine). All have similar sensitivity (89%-91%) and specificity (78%-86%) for the diagnosis of coronary disease. For risk stratification, the risk of future cardiac events is related to the extent and severity of perfusion abnormalities. Pharmacologic stress testing permits risk stratification as early as 1 to 4 days following an acute myocardial infarction, and is superior to exercise stress testing in this regard. Similarly, it identifies patients at high risk for perioperative cardiac events prior to noncardiac surgery. This review summarizes the current evidence available regarding the diagnostic and prognostic use of pharmacologic stress testing.

The physiologic evaluation of patients with lung cancer being considered for resectional surgery

The preoperative physiologic assessment of a patient being considered for surgical resection of lung cancer must consider the immediate perioperative risks from comorbid cardiopulmonary disease, the long-term risks of pulmonary disability, and the threat to survival due to inadequately treated lung cancer. As with any planned major operation, especially in a population predisposed to atherosclerotic cardiovascular disease by cigarette smoking, a cardiovascular evaluation is an important component in assessing perioperative risks. Measuring the FEV(1) and the diffusing capacity of the lung for carbon monoxide (DLCO) measurements should be viewed as complementary physiologic tests for assessing risk related to pulmonary function. If there is evidence of interstitial lung disease on radiographic studies or undue dyspnea on exertion, even though the FEV(1) may be adequate, a DLCO should be obtained. In patients with abnormalities in FEV(1) or DLCO identified preoperatively, it is essential to estimate the likely postresection pulmonary reserve. The amount of lung function lost in lung cancer resection can be estimated by using either a perfusion scan or the number of segments removed. A predicted postoperative FEV(1) or DLCO < 40% indicates an increased risk for perioperative complications, including death, from lung cancer resection. Exercise testing should be performed in these patients to further define the perioperative risks prior to surgery. Formal cardiopulmonary exercise testing is a sophisticated physiologic testing technique that includes recording the exercise ECG, heart rate response to exercise, minute ventilation, and oxygen uptake per minute, and allows calculation of maximal oxygen consumption (.VO(2)max). Risk for perioperative complications can generally be stratified by .VO(2)max. Patients with preoperative .VO(2)max > 20 mL/kg/min are not at increased risk of complications or death; .VO(2)max< 15 mL/kg/min indicates an increased risk of perioperative complications; and patients with .VO(2)max < 10 mL/kg/min have a very high risk for postoperative complications. Alternative types of exercise testing include stair climbing, the shuttle walk, and the 6-min walk. Although often not performed in a standardized manner, stair climbing can predict .VO(2)max. In general terms, patients who can climb five flights of stairs have O(2)max > 20 mL/kg/min. Conversely, patients who cannot climb one flight of stairs have .VO(2)max < 10 mL/kg/min. Data on the shuttle walk and 6-min walk are limited, but patients who cannot complete 25 shuttles on two occasions will have .VO(2)max < 10 mL/kg/min. Desaturation during an exercise test has been associated with an increased risk for perioperative complications. Lung volume reduction surgery (LVRS) for patients with severe emphysema is a controversial procedure. Some reports document substantial improvements in lung function, exercise capability, and quality of life in highly selected patients with emphysema following LVRS. Case series of patients referred for LVRS indicate that perhaps 3 to 6% of these patients may have coexisting lung cancer. Anecdotal experience from these case series suggest that patients with extremely poor lung function can tolerate combined LVRS and resection of the lung cancer with an acceptable mortality rate and good postoperative outcomes. Combining LVRS and lung cancer resection should probably be limited to those patients with heterogeneous emphysema, particularly emphysema limited to the lobe containing the tumor.

Assessment and reporting of perioperative cardiac risk by Canadian general internists: art or science?

OBJECTIVE

Physicians may use several validated risk indices to estimate perioperative cardiac risk, but there is little evidence for interventions to reduce this risk. We were interested in evaluating how general internists assess, define, communicate, and attempt to modify perioperative cardiac risk.

DESIGN

Cross-sectional survey of all 312 general internists in the Canadian Society of Internal Medicine with Canadian mailing addresses; 117 (38%) responded.

RESULTS

Respondents' mean age was 46 years, 79% were male, and on average they did 17 preoperative consults per month. Of the 104 respondents who routinely performed preoperative assessments, 96% (100/104) informed patients of their perioperative cardiac risk, but 77% did so only subjectively (i.e., stating risk as low, moderate, or high). Respondents provided 8, 27, and 12 different definitions for low, moderate, and high risk, respectively, with marked variability in the range of definitions they provided: from <1% to < 20% for "low risk," from 1% to 2% to 20% to 50% for "moderate risk," and from >2% to >50% for "high risk." The 67% of respondents who reported using a perioperative cardiac risk index used a variety of indices and exhibited just as much variability in their risk estimates and definitions as those who didn't use risk indices. While virtually all advised perioperative beta blockade in patients with known coronary artery disease, they varied substantially in the recommended agent or dose; further, these internists were evenly split on whether antiplatelet agents should be held or continued perioperatively.

CONCLUSIONS

These physicians differed widely in their assessment of perioperative cardiac risk and their definitions of low, moderate, or high risk. This raises concerns about whether patients (and surgeons) are provided with adequate information to make fully informed decisions about the potential risks of elective surgical operations.

Preoperative risk stratification using electron beam computed tomography in elective vascular surgery: relationship to clinical risk prediction and postoperative complications

We studied the utility of electron beam computed tomography as a screening test for the cardiovascular risk of elective vascular surgery. In 45 patients undergoing principally carotid and aortic surgical procedures, coronary artery calcification was prevalent and severe, and related to the clinically predicted cardiovascular risk of the procedure. However, only the clinically predicted surgical risk, and not coronary artery calcification, was related to the incidence of perioperative cardiovascular complications.

Usefulness of clinical risk markers and ischemic threshold to stratify risk in patients undergoing major noncardiac surgery

The risk of cardiac events in patients undergoing major noncardiac surgery is dependent on their clinical characteristics and the results of stress testing. The purpose of this study was to develop a composite approach to defining levels of risk and to examine whether different approaches to prophylaxis influenced this prediction of outcome. One hundred forty-five consecutive patients (aged 68 +/- 9 years, 79 men) with >1 clinical risk variable were studied with standard dobutamine-atropine stress echo before major noncardiac surgery. Risk levels were stratified according to the presence of ischemia (new or worsening wall motion abnormality), ischemic threshold (heart rate at development of ischemia), and number of clinical risk variables. Patients were followed for perioperative events (during hospital admission) and death or infarction over the subsequent 16 +/- 10 months. Ten perioperative events occurred in 105 patients who proceeded to surgery (10%, 95% confidence interval [CI] 5% to 17%), 40 being cancelled because of cardiac or other risk. No ischemia was identified in 56 patients, 1 of whom (1.8%) had a perioperative infarction. Of the 49 patients with ischemia, 22 (45%) had 1 or 2 clinical risk factors; 2 (9%, 95% CI 1% to 29%) had events. Another 15 patients had a high ischemic threshold and 3 or 4 risk factors; 3 (20%, 95% CI 4% to 48%) had events. Twelve patients had a low ischemic threshold and 3 or 4 risk factors; 4 (33%, 95% CI 10% to 65%) had events. Preoperative myocardial revascularization was performed in only 3 patients, none of whom had events. Perioperative and long-term events occurred despite the use of beta blockers; 7 of 41 beta blocker-treated patients had a perioperative event (17%, 95% CI 7% to 32%); these treated patients were at higher anticipated risk than untreated patients (20 +/- 24% vs 10 +/- 19%, p = 0.02). The total event rate over late follow-up was 13%, and was predicted by dobutamine-atropine stress echo results and heart rate response.

Perioperative myocardial infarction in noncardiac surgery: the diagnostic and prognostic role of cardiac troponins

Despite the number of technologies used, the diagnosis of perioperative myocardial infarction is still a challenge. Studies conducted in surgical series have demonstrated that cardiac troponins (cTns) have both a superior diagnostic sensitivity and specificity, compared with other traditional techniques, and an independent power to predict short- and long-term prognosis. Nevertheless, some points need to be clarified. They include the usefulness of cTns in patients with end-stage renal failure; the standardization of the cTns cut-off for the diagnosis of myocardial injury; the timing of postoperative blood samplings; the cost-effectiveness of a screening in asymptomatic patients; and the possible therapeutic strategies.

Implementation and evaluation of guidelines for preoperative testing in a tertiary hospital

The aim of this study was to determine the extent of unnecessary investigation performed as part of the preoperative preparation of elective surgical patients in a teaching hospital and to audit the effect of guidelines and education designed to reduce unnecessary investigation. Guidelines were developed for preoperative anaesthetic investigation for elective surgical procedures in patients over one year of age according to internationally accepted criteria, with some adjustment for local differences in patient morbidity. Forrms outlining these criteria were placed in all operating theatres and anaesthetists were asked to determine whether tests performed were indicated or not, according to these criteria, over a two-week period, in each patient undergoing elective surgery. Tests indicated for surgical reasons were excluded. These same guidelines were then issued to all surgical departments along with explanatory lectures. The audit was repeated six months later and results compared. The incidence of over-investigation decreased from 13.8% to 11.6% (P = 0.03) without a significant increase in under-investigation (0.7 v 1.0%; P = 0.2). This study highlights the incidence of unwarranted screening tests in patients presenting for elective surgery and the role of protocols and ongoing education in reducing this incidence.

Perioperative cardiovascular risk stratification of patients with diabetes who undergo elective major vascular surgery

BACKGROUND

The importance of diabetes mellitus (DM) as an independent risk factor for perioperative cardiac morbidity after vascular surgery is controversial. This study examined the impact of DM on perioperative outcomes and length of stay in patients who underwent major vascular surgery.

METHODS

Patients who underwent elective aortic reconstruction (n = 2792), lower extremity bypass (n = 3838), carotid endarterectomy (n = 5522), and major amputation (n = 3883) from 1997 to 1999 were identified in the National Surgical Quality Improvement Program database of the Department of Veterans Affairs. Outcomes assessed were death, cardiovascular complications (myocardial infarction, stroke, need for cardiopulmonary resuscitation), and length of stay. Multivariable logistic and linear regression models were used to control for patient demographics, procedure type, comorbidities, and diabetic complications.

RESULTS

Before adjustment for potential confounders, patients with diabetes had a higher incidence rate of perioperative death (3.9% versus 2.6%; P =.001) and cardiovascular complications (3.3% versus 2.6%; P =.01) when compared with patients without diabetes. After controlling for comorbid conditions, procedure type, and diabetic complications, only patients with DM who underwent treatment with insulin were at statistically increased risk for cardiovascular complications (odds ratio [OR], 1.48; 95% CI, 1.15 to 1.91). Neither DM treated with insulin (OR, 1.10; 95% CI, 0.85 to 1.41) nor DM treated with oral medications (OR, 0.96; 95% CI, 0.73-1.28) was an independent risk factor for death. Important independent risk factors for death included several conditions that are commonly associated with diabetes, including proteinuria, elevated creatinine level, history of congestive heart failure, and history of cerebrovascular accident. DM was also found to increase length of stay by as much as 38% even after adjustment for comorbidities.

CONCLUSION

Patients with diabetes have a higher incidence rate of death and cardiovascular complications. However, after controlling for specific comorbid conditions, the only independent association was between patients with insulin treatment and the risk of cardiovascular complications. DM does not appear to be an independent risk factor for postoperative mortality. All patients with diabetes, regardless of insulin use, have a prolonged length of stay after major 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.

Perioperative cardiac complications

Although infrequent, perioperative cardiac complications are a source of major morbidity and mortality. As the population ages, the prevalence of cardiovascular disease is increasing. For physicians who refer patients for surgery as well as for clinicians directly involved in perioperative medical care, an understanding of perioperative cardiac complications, reduction of such complications, and treatment of complications is essential. This article summarizes the approach to perioperative hypertension, hypotension, myocardial ischemia, myocardial infarction, and congestive heart failure.

Adverse cardiac events after surgery: assessing risk in a veteran population

OBJECTIVE

To establish rates of and risk factors for cardiac complications after noncardiac surgery in veterans.

DESIGN

Prospective cohort study.

SETTING

A large urban veterans affairs hospital.

PARTICIPANTS

One thousand patients with known or suspected cardiac problems undergoing 1,121 noncardiac procedures.

MEASUREMENTS

Patients were assessed preoperatively for important clinical variables. Postoperative evaluation was done by an assessor blinded to preoperative status with a daily physical examination, electrocardiogram, and creatine kinase with MB fraction until postoperative day 6, day of discharge, death, or reoperation (whichever occurred earliest). Serial electrocardiograms, enzymes, and chest radiographs were obtained as indicated. Severe cardiac complications included cardiac death, cardiac arrest, myocardial infarction, ventricular tachycardia, and fibrillation and pulmonary edema. Serious cardiac complications included the above, heart failure, and unstable angina.

MAIN RESULTS

Severe and serious complications were seen in 24% and 32% of aortic, 8.3% and 10% of carotid, 11.8% and 14.7% of peripheral vascular, 9.0% and 13.1% of intraabdominal/intrathoracic, 2.9% and 3.3% of intermediate-risk (head and neck and major orthopedic procedures), and 0.27% and 1.1% of low-risk procedures respectively. The five associated patient-specific risk factors identified by logistic regression are: myocardial infarction < 6 months (odds ratio [OR], 4.5; 95% confidence interval [CI], 1.9 to 12.9), emergency surgery (OR, 2.6; 95% CI, 1.2 to 5.6), myocardial infarction > 6 months (OR, 2.2; 95% CI, 1.4 to 3.5), heart failure ever (OR, 1.9; 95% CI, 1.2 to 3.0), and rhythm other than sinus (OR, 1.7; 95% CI, 0.9 to 3.2). Inclusion of the planned operative procedure significantly improves the predictive ability of our risk model.

CONCLUSIONS

Five patient-specific risk factors are associated with high risk for cardiac complications in the perioperative period of noncardiac surgery in veterans. Inclusion of the operative procedure significantly improves the predictive ability of the risk model. Overall cardiac complication rates (pretest probabilities) are established for these patients. A simple nomogram is presented for calculation of post-test probabilities by incorporating the operative procedure.

Utility of prognostic stratification in adults with community-acquired bacterial meningitis

Prognostic stratification uses baseline clinical features to subdivide patients into subgroups with different risks for a particular outcome. We review the importance of prognostic stratification in internal medicine, in infectious diseases, and in adults with community-acquired bacterial meningitis.

Cardiac risk assessment for noncardiac surgery: current concepts

Strategies for perioperative risk assessment in patients undergoing noncardiac surgery vary among physicians and are aimed to estimate the risk and minimize complications. We propose simplistic guidelines for assessing and modifying risk for patients undergoing a wide variety of procedures.

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.

Cardiac Investigation and Intervention Prior to Thoraco-abdominal Aneurysm Repair: Coronary Angiography in 35 Patients

OBJECTIVE

retrospective studies indicate a high risk of cardiac events in patients undergoing thoraco-abdominal aneurysm repair. We aimed to determine the prevalence of coronary disease in these patients, define the role of non-invasive cardiac testing and assess the short-term outcome of coronary re-vascularisation.

DESIGN

a prospective cohort study of consecutive patients referred to a single surgeon.

MATERIALS AND METHODS

forty patients recruited over 16 months (Type I, 6; II, 11; III, 8; IV, 15). Dobutamine stress echocardiography, coronary angiography and coronary re-vascularisation (PTCA or CABG) were performed according to a pragmatic protocol. Main outcome measures were the prevalence of coronary artery disease, sensitivity and specificity of clinical assessment and non-invasive cardiac testing, and adverse events associated with coronary investigation and intervention.

RESULTS

seven patients (17.5%) were stratified as having high perioperative cardiac risk. The majority of patients (23, 57.5%) had no cardiac risk factor other than the operation type. Five patients (12.5%) had inducible ischaemia on non-invasive testing. Fourteen patients (40%) had haemodynamically significant coronary artery stenoses, of whom 12 (34%) underwent coronary revascularisation. Dobutamine stress echocardiography demonstrated 100% specificity and 71% sensitivity for the detection of significant coronary artery lesions. Coronary re-vascularisation by three-vessel bypass grafting was complicated by non-fatal stroke in one patient. Thirty-five patients (87.5%) proceeded to aneurysm repair. No patient who had been adequately investigated suffered a cardiac complication.

CONCLUSIONS

the 40% prevalence of coronary artery disease in these patients is comparable to that of other patients undergoing arterial surgery. Non-invasive testing proved beneficial, both in screening low-risk patients and planning intervention in patients at higher risk. An aggressive approach to intervention was associated with an acceptable complication rate and favourable short-term outcome.

Perioperative beta-blocker withdrawal and mortality in vascular surgical patients

OBJECTIVE

Our purpose was to determine the effect of postoperative beta-blocker withdrawal on mortality and cardiovascular events after vascular surgery.

METHODS

Detailed data were collected on perioperative cardiovascular medication use and discontinuation and cardiovascular risk factors among consecutive major vascular surgical procedures at two university hospitals.

RESULTS

A total of 140 patients received beta-blockers preoperatively. Mortality in the 8 patients who had beta-blockers discontinued postoperatively (50%) was significantly greater than in 132 patients who had beta-blockers continued (1.5%, odds ratio 65.0, P<.001). The effect of beta-blocker discontinuation was unaffected by adjustment by stratification for risk factors (all P< or =.01), for contraindications to restarting beta-blockers (P = .006), and by multivariable analyses adjusting for potential confounders (adjusted odds ratio 17.0, P =.01). beta-Blocker discontinuation also was associated with increased cardiovascular mortality (0% vs 29%, P =.005) and postoperative myocardial infarction (odds ratio 17.7, P =.003).

CONCLUSION

Discontinuing beta-blockers immediately after vascular surgery may increase the risk of postoperative cardiovascular morbidity and mortality.

Perioperative cardiovascular evaluation. Step-by-step approach to risk assessment and follow-up care

One of the integral responsibilities in primary care medicine is medical consultation, especially when a surgical procedure is contemplated. A good grasp of the elements of multiple specialties and an understanding of the complexity of a proposed operation are essential for an appropriate preoperative evaluation. This article covers the steps in assessing cardiovascular risk in candidates for noncardiac surgery, including consideration of patient-specific and surgery-specific factors. The authors also recommend close postoperative follow-up to reduce morbidity and mortality.

Cost Containment in Vascular Surgery

In the last decade, the delivery of health care and the role of the physician have undergone radical change. With the ad vent of managed care and the tightening of restrictions by Medicare and insurance companies, physicians have been required to review, re-engineer, and revitalize their role. Increasing financial pressures at the hospital level have caused administrators to cut costs at all levels. It is imper ative that physicians take an active role in cost containment so that the quality of care is not sacrificed. Cost containment in vascular surgery is an urgent priority in health care. Copyright © 2000 by W.B. Saunders Company.

Stress nuclear myocardial perfusion imaging versus stress echocardiography: prognostic comparisons

The use of noninvasive stress cardiac imaging for stratifying risk in patients with known or suspected coronary artery disease is growing as a tool for identification of the subgroup most likely to benefit from the expense and risk of more invasive procedures, including cardiac catheterization and coronary revascularization. In this setting, it is especially important that a test be able to identify patients with sufficiently low risk that clinicians are comfortable in deferring such interventions, especially in those with other markers of increased risk. Previous data have shown that cardiac risk is most closely related to the presence and extent of jeopardized viable myocardium on noninvasive stress cardiac imaging. Although stress echocardiography may have comparable ability to detect coronary artery disease, current data suggest that stress echocardiography detects significantly less jeopardized viable myocardium than stress nuclear myocardial perfusion imaging and consequently fewer patients at risk for cardiac events. Stress nuclear myocardial perfusion imaging may therefore have important advantages for risk stratification and the direction of future care of patients with known or suspected coronary artery disease.

Impact of radionuclide ventriculography prior to elective abdominal aortic reconstruction

We evaluated how preoperative radionuclide ventriculography (RNV) influences the clinical management of 96 patients referred for elective infrarenal abdominal aortic surgery. Of these, 11 had aortoiliac occlusive disease and 85 an abdominal aortic aneurysm. In 89 patients (93%), there was a known history or clinical evidence of coronary artery disease prior to RNV. The scan was abnormal in half the patients. There were 56 patients with left ventricular ejection fraction (LVEF) > 50% and 40 with LVEF < or = 50%. The LVEF ranged between 10% and 88% with a mean of 52.8+/-14.1%. There was normal wall motion in 56 patients and wall abnormalities were present in 40, including four LV aneurysms. After initial assessment, 19 patients did not proceed to surgery for a variety of reasons. Cardiology consultation was requested in 11 patients, six of which were delayed or turned down for surgery mainly on cardiac grounds. Only one of these underwent cardiac catheterization. Of the remaining 77 patients who underwent surgery, 15 were seen by a cardiologist and one was delayed in order to optimize his cardiac status. No patient underwent prophylactic coronary angioplasty/stenting or revascularization preoperatively. In addition, based on the RNV results and in conjunction with the clinical findings, six patients had pulmonary artery catheters inserted either the night prior to operation (n = 3) or after induction to anaesthesia (n = 3). This is the largest reported British series of cardiac testing using RNV prior to abdominal aortic surgery. Coronaryartery disease is very common amongst such patients. RNV influences our decision-making and patientselection. An abnormal result may alter the clinical management, lead to a cardiology referral (26/96, 27% in this series) and have anaesthetic implications.

Cost-effectiveness of stress echocardiography and nuclear perfusion imaging

Cost-effectiveness analysis is a method of comparing societal economic value of 2 different strategies. Ideally, it defines accurate test-related (direct and downstream) costs and appropriately converts differential patient outcomes into a dollar value. The likelihood that cost-effectiveness analysis translated into a policy-making tool will enhance health care and/or control costs is dependent on the validity of numerous assumptions about relative costs, patient outcomes, and generalizability of the literature to regional capabilities. The purpose of this report is to review the concept of cost-effectiveness analysis as it applies to stress echocardiography and stress myocardial perfusion imaging for selected patient subsets.

The future of anesthesiology is perioperative medicine

Anesthesiology faces many challenges in the years ahead. To meet these challenges, the author hypothesizes that perioperative medicine, which includes the spectrum of care from preoperative assessment to postoperative care, offers the best chance for the specialty to survive and prosper. The history of perioperative medicine is reviewed and a discussion of how such change will benefit anesthesiology is included. Implementation may be difficult and the author explores how a transition from traditional procedure-focused anesthesiology to a broader based specialty may be accomplished. The special needs of perioperative medicine and how they differ from anesthesiology are also presented.

Myocardial ischemia detected by transesophageal echocardiography in a patient undergoing peripheral vascular surgery

Prevention and early treatment of myocardial ischemia remain among the primary goals of the anesthesiologist taking care of high-risk patients, such as those undergoing vascular surgery. Guidelines have been published to assist in directing preoperative evaluation and optimization of cardiovascular status. Although perioperative monitoring allows early detection of ischemic events, all monitors have limitations that must be understood before they can be used effectively. We present a case of severe intraoperative myocardial dysfunction detected only by transesophageal echocardiography in a patient undergoing a peripheral vascular procedure. Preoperative and intraoperative management is also discussed.

Hypertension

The current JNC-VI criteria for diagnosis and classification of hypertension are discussed. The laboratory evaluation of both essential and secondary hypertension is examined, and recommendations are made in this regard. Finally, the complications and treatment of essential hypertension and the causes and management of resistant hypertension are discussed.

Mild renal failure is associated with adverse outcome after cardiac valve surgery

The present study was performed to ascertain whether the presence of mild renal failure (defined as a serum creatinine concentration of 1. 5 to 3.0 mg/dL) is an independent risk factor for adverse outcome after cardiac valve surgery. An extensive set of preoperative and postoperative data was collected in 834 prospectively evaluated patients undergoing cardiac valve surgery at 14 Veterans Affairs Medical Centers. Univariate and multivariable analyses were performed to determine whether an independent association of mild renal dysfunction with adverse outcomes was present. Patients with mild renal failure had significantly greater 30-day mortality rates (P = 0.001; 16% versus 6%) and frequency of postoperative bleeding (P = 0.023; 16% versus 8%), respiratory complications (P = 0.02, 29% versus 16%), and cardiac complications (P = 0.002; 18% versus 7%) than patients with normal renal function (serum creatinine <1.5 mg/dL) when controlling for multiple other variables. The presence of a serum creatinine concentration of 1.5 to 3.0 mg/dL is significantly and independently associated with adverse outcomes after cardiac valve surgery.

Update on electroconvulsive therapy (ECT) in older adults

Electroconvulsive therapy (ECT) is used increasingly in the older adult population for major depression, particularly when depression is not responsive to medications, when antidepressants are not tolerated due to side effects, or when depression is accompanied by life-threatening complications such as severe weight loss or catatonia where a rapid definitive response is required. ECT is considered a low-risk procedure that can be successfully done in medically ill older adults, but it is associated with a brief period of increased blood pressure and pulse leading to increased myocardial oxygen demand. ECT may cause delirium, particularly in the cognitively impaired older. As successful management of older patients undergoing a course of ECT often involves geriatricians and other medical practitioners, this review provides an update on the indications for ECT, how it is done, the common complications seen after the procedure, and its efficacy. Finally, specific recommendations for management are made.