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)

Risk assessment using single-photon emission computed tomographic technetium-99m sestamibi imaging

OBJECTIVES

This review summarizes the results of single-photon emission computed tomographic (SPECT) technetium-99m (Tc-99m) tracer imaging in patients with stable symptoms, patients with acute coronary syndromes, patients undergoing major non-cardiac surgery and patients with chest pain in the emergency department.

BACKGROUND

Previous studies have examined the prognostic value of stress thallium imaging in several subsets of patients with ischemic heart disease. At present, >50% of myocardial perfusion studies are performed with technetium-labeled tracers in the United States. Furthermore, there is a shift from diagnostic to the prognostic utility of stress testing. There are important differences between technetium-labeled tracers and thallium-201. It is therefore important to review the prognostic value of technetium-labeled tracers.

METHODS

We analyzed published reports in English on risk assessment using Tc-99m perfusion tracers. Results. The largest experience is in patients with stable symptoms, comprising >12,000 patients in 14 studies. In these patients, normal stress SPECT sestamibi images were associated with an average annual hard event rate of 0.6% (death or nonfatal myocardial infarction [MI]). In contrast, patients with abnormal images had a 12-fold higher event rate (7.4% annually). Both fixed and reversible defects are prognostically important, and quantitative analysis shows increased risk in relation to the severity of the abnormality. These results are similar to those obtained with thallium-201.

CONCLUSIONS

Patients with stable chest pain syndromes and normal stress SPECT sestamibi images have a very low risk of death or nonfatal MI. It is highly unlikely that coronary revascularization can improve survival in such patients. Patients with abnormal images have an intermediate to high risk for future cardiac events, depending on the degree of the abnormality. Further prospective studies comparing aggressive medical therapy with coronary revascularization in these patients are warranted.

Operations on patients deemed "unfit for operation and anaesthesia": what are the consequences?

BACKGROUND

The decision "patient unfit for anaesthesia and operation" is likely to cause a delay of the scheduled operation. This retrospective evaluation was done: 1) to determine the correctness of preoperative tentative diagnoses of coexisting diseases making anaesthesia and operation excessively risky in relation to the physician's training status; 2) to examine the question of whether preoperative medical management modified according to the anaesthesiologist's suggestions had a positive impact on the perioperative course.

METHODS

The medical records of patients scheduled for elective non-cardiac surgery who were rated "unfit for operation and anaesthesia" were evaluated. The accuracy of the tentative diagnoses was examined for relation to the training status of the anaesthesiologists. The preoperative management was tested for its impact on postoperative outcome.

RESULTS

During the observation period 16,122 patients underwent preoperative anaesthesiological assessment; 1021 (6.3%) were initially considered to be unfit for operation and anaesthesia. The records of 807 patients were available for review. The accuracy of the tentative diagnoses was 70%, and was not significantly affected by the training status of the physicians (P = 0.022). Four hundred and seventeen patients were excluded from the second part of the investigation (discharged without operation, underwent operation using local anaesthesia or tentative diagnosis not confirmed). Three hundred and ninety patients were operated under general anaesthesia. Group I (n = 216) was managed according to the anaesthesiologist's suggestions and was found to have a significantly lower complication rate (18.1%) than group II (n = 174) in which the suggestions from the preoperative assessment were ignored (32.2%; P < 0.05). The perioperative mortality rate in group I was 2.3% compared with 5.2% in group II (n.s.; P > 0.05).

CONCLUSIONS

We conclude that the anaesthesiology decision "patient unfit for operation and anaesthesia" has a high accuracy, independent of the anaesthesiologist's training status, and that preoperative medical management significantly reduces complications.

Risk of patients with severe aortic stenosis undergoing noncardiac surgery

Aortic stenosis (AS) is a major risk factor for perioperative cardiac events in patients undergoing noncardiac surgery. We previously showed that selected patients with AS who were not candidates for, or refused, aortic valve replacement could undergo noncardiac surgery with acceptable risk. We extended our previous experience over a subsequent 5-year period by retrospectively analyzing the perioperative course of all patients with severe AS (aortic valve area index < 0.5 cm2/m2 or mean gradient > 50 mm Hg), determined with Doppler echocardiography or cardiac catheterization, who underwent noncardiac surgery. Nineteen patients underwent 28 surgical procedures: 22 elective and 6 emergency. The types of these procedures were 12 orthopedic, 6 intraabdominal, 4 vascular, 4 urologic, 1 otolaryngologic, and 1 thoracic. Mean age was 75 +/- 8 years. Of the 19 patients, 16 (84%) had > or = 1 symptom: dyspnea, angina, syncope, or presyncope. Mean left ventricular ejection fraction was 61 +/- 11%. The type of anesthesia was general in 26 procedures and continuous spinal in 2. Intraarterial monitoring of blood pressure was used in 20 of the 28 surgical procedures. Intraoperative hypotensive events were treated promptly, primarily with phenylephrine. In all cases the anesthesia team was aware of the severity of the AS and integrated this into the anesthetic plan. Two patients (elective operation in 1 and emergency in 1) had complicated postoperative courses and died. There were no other intraoperative or postoperative events in any of the other patients. Although aortic valve replacement remains the primary treatment for patients with severe AS, selected patients with severe AS, who are otherwise not candidates for aortic valve replacement, can undergo noncardiac surgery with acceptable risk when appropriate intraoperative and postoperative management is used.

Stress echocardiography: recommendations for performance and interpretation of stress echocardiography. Stress Echocardiography Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography

Cardiovascular stress testing remains the mainstay of provocative evaluation for patients with known or suspected coronary artery disease. Stress echocardiography has become a valuable means of cardiovascular stress testing. It plays a crucial role in the initial detection of coronary disease, in determining prognosis, and in therapeutic decision making. The purpose of this document is to outline the recommended methodology for stress echocardiography with respect to personnel and equipment as well as the clinical use of this recently developed technique. Specific limitations will also be discussed.

A Therapeutic Commentary

ABSTRACT: Thirty-one million patients in the United States undergo surgical procedures every year. Approximately 10%-the majority of these with hypertension-are at an increased risk for perioperative and postoperative cardiovascular morbidity and mortality. Thus, hypertensive patients requiring surgery, especially the 2.1 million undergoing noncardiac procedures, should be evaluated carefully for the magnitude, and if severe, the cause of the hypertension. Additionally, their associated metabolic and cardiovascular status should be characterized and corrected with aggressive therapy. Hypertensive patients with known ischemic heart disease, those with multiple risk factors for ischemic heart disease (IHD), some with valvular heart disease, and those with congestive heart failure should be evaluated for their ability to perform the physical and social activities of everyday life, and, when necessary, have formal stress testing. Most studies suggest that blood pressures of 180/110 mm Hg or greater are associated with a greater risk for perioperative ischemic events. Therefore, the goals of blood pressure control should be to reduce the blood pressure without jeopardizing organ function. Antihypertensive medication should be administered until the time of surgery. beta-Receptor blockers should be instituted or continued in patients with angina and in some patients with congestive heart failure. Those without prior antihypertensive therapy might be best treated with beta-blocker therapy perioperatively as evidenced by the Multicenter Study of Perioperative Research Group with atenolol and those earlier studies with metoprolol. The risks of the surgery should be discussed with the patient so the risks can be weighed against the expected benefit. Studies suggest that perioperative risk for any patient, and especially patients with hypertension, are in part related to the adrenergic arousal before, during, and after the procedure as evidenced by the rise in heart rate and blood pressure, along with the liberation of clotting facators and increased risk for plaque rupture, coronary vasoplasm, and consequent myocardial infarction and fibrosis.

Coronary artery disease in patients undergoing lung volume reduction surgery for emphysema

OBJECTIVES

Most patients with severe pulmonary emphysema referred for lung volume reduction surgery (LVRS) have a long-standing history of cigarette smoking. Coronary artery disease (CAD) predisposes to perioperative cardiac complications. Since symptoms and signs of myocardial ischemia are often absent in patients with severe ventilatory impairment even during exercise, we investigated the prevalence of CAD in candidates for LVRS by angiography.

DESIGN

We prospectively studied the prevalence of CAD by angiography and assessed the CAD risk factor profile in 41 candidates for LVRS (26 men, 15 women; mean age, 66+/-6.8 years; range, 52 to 76 years), who had no current symptoms or a history of myocardial ischemia.

RESULTS

In six patients (15%), asymptomatic but significant coronary lesions (> 70% stenosis) were detected. In five patients, these findings altered the clinical management. Patients with CAD had significant higher cholesterol levels, tended to have smoked more, and had more often additional vascular risk factors.

CONCLUSIONS

We found a high prevalence of angiographically significant but clinically silent CAD in this particular population of heavy smokers with advanced emphysema.

Outcomes and cost implications of a clinical-based algorithm to guide the discriminate use of stress imaging before noncardiac surgery

Approximately 8 million patients at risk for coronary artery disease undergo noncardiac surgery annually in the United States. This study defined the appropriateness and cost of evaluating these patients with stress imaging tests. Before noncardiac surgery, 178 consecutive patients were prospectively studied by stress imaging. Pretest cardiac risk (low, intermediate, high) was established by interviewing the referring physician and separately by a cardiologist on the basis of the nature of noncardiac surgery and Eagle's clinical criteria. Patients were followed-up for alterations in management and perioperative events until hospital discharge. Referring physicians and cardiologists identified low risk in 24% and 54% of patients, respectively (p < 0.0001). Of 96 patients identified as low risk by cardiologists, 75 had minor surgery and 21 had major surgery, but no clinical risk factors. In the remaining 82 patients with major surgery, ischemia and other severe abnormalities were detected in 19 (23%) patients. At follow-up, no perioperative complications occurred in minor surgery; one patient with major surgery but no clinical risk factors died from complications related to hypertrophic cardiomyopathy. Patients with at least one clinical risk factor undergoing major surgery but who did not have ischemia on stress testing (n = 63) had two complications (infarction and unstable angina). Intervention (revascularization and surgical cancellation) was probably the explanation for the absence of events in 19 patients with ischemia. With a weighted mean Medicare reimbursement ($386), the use of a simple selection algorithm based on noncardiac surgery and clinical risk to avoid testing low-risk patients would have an average cost of $214 per patient, representing a 45% savings.

Usefulness of preoperative noninvasive radionuclide testing for detecting coronary artery disease in candidates for liver transplantation

This study, conducted in 87 candidates for liver transplantation, shows that neither stress perfusion imaging nor rest radionuclide ventriculography appear useful for preoperative cardiac risk assessment because most patients have normal studies and a favorable outcome. Routine myocardial function testing "to rule out cardiomyopathy" in asymptomatic (from a cardiac standpoint) patients with end-stage alcoholic liver disease should be abandoned.