Role of dobutamine stress echocardiography for preoperative cardiac risk assessment before major vascular surgery: a diagnostic tool comes of age

BACKGROUND

Cardiac complications are a major cause for perioperative mortality and morbidity. Also, the presence and severity of underlying coronary artery disease (CAD) determine long-term prognosis after successful surgery.

AIM

This overview evaluates the additional value of dobutamine stress echocardiography (DSE) to common clinical cardiac risk factors and other noninvasive cardiac imaging modalities for perioperative and late cardiac prognosis.

RESULTS

DSE provides theattending physician with preoperative prognostic information for perioperative and long-term prognosis for cardiac events. It also enables the selection of high risk patients for evaluation of cardiac risk reduction therapies.

CONCLUSIONS

DSE is a useful tool for preoperative cardiac risk evaluation in addition to common clinical cardiac risk factors.

Improved cardiac risk stratification in major vascular surgery with dobutamine-atropine stress echocardiography

OBJECTIVES

This study sought to optimize preoperative cardiac risk stratification in a large group of consecutive candidates for vascular surgery by combining clinical risk assessment and semiquantitative dobutamine-atropine stress echocardiography.

BACKGROUND

Dobutamine-atropine stress echocardiography has been used for the prediction of perioperative cardiac risk in a small group of patients scheduled for elective major vascular surgery on the basis of the presence or absence of stress-induced regional left ventricular wall motion abnormalities.

METHODS

Clinical risk assessment and dobutamine-atropine stress echocardiography were performed in 302 consecutive patients presenting for major vascular surgery. The extent and severity of stress wall motion abnormalities and the heart rate at which they occurred, in addition to the presence of wall motion abnormalities at rest, were assessed.

RESULTS

The absence of clinical risk factors (angina, diabetes, Q waves on the electrocardiogram, symptomatic ventricular tachyarrhythmias, age > 70 years) identified a low risk group of 100 patients with a 1% cardiac event rate (unstable angina). Dobutamine-atropine stress echocardiographic findings were positive in 72 patients. Twenty-seven patients had a perioperative cardiac event (cardiac death in 5, nonfatal infarction in 12, unstable angina pectoris in 10); all 27 patients had positive stress test results (positive predictive value 38%, negative predictive value 100%). The semiquantitative assessment of the extent and severity of ischemia did not provide additional prognostic information in patients with positive test results. In contrast, the heart rate at which ischemia occurred defined a high risk group with a low ischemic threshold (38 patients with 20 events [53%]) and an intermediate risk group with a high ischemic threshold (34 patients with 7 events [21%]). All 5 patients with a fatal outcome and 8 of 12 with a nonfatal myocardial infarction were in the high risk group with a low ischemic threshold.

CONCLUSIONS

Clinical variables identify 33% of patients at very low risk for perioperative complications of vascular surgery in whom further testing is redundant. In all other candidates, dobutamine-atropine stress echocardiography is a powerful tool that identifies those patients at intermediate risk and a small group at very high risk. Risk stratification with a combination of clinical assessment and pharmacologic stress echocardiography has the potential to facilitate clinical decision making and conserve resources.

Comparison of effects of high-dose and low-dose aspirin on restenosis after femoropopliteal percutaneous transluminal angioplasty

BACKGROUND

Long-term treatment with aspirin is recommended in patients with large-vessel peripheral arterial disease since these patients have a high risk of death from cardiovascular causes. Recent studies have demonstrated the prophylactic effect of low-dose aspirin in reducing the risk of cardiovascular events. Since aspirin is also recommended for prevention of late recurrence after peripheral angioplasty, the present study was undertaken to compare the effects of high-dose (1000 mg/d) and low-dose (100 mg/d) aspirin on long-term patency after femoropopliteal angioplasty.

METHODS AND RESULTS

Two hundred sixteen patients treated successfully by percutaneous transluminal angioplasty for femoropopliteal lesions were randomly allocated to therapy with either 1000 or 100 mg aspirin daily. The follow-up was 24 months. The long-term results were analyzed using the Kaplan-Meier method, and differences between curves of cumulative patency were determined with the Wilcoxon and log-rank statistics. Complete follow-up information (patency after 24 months, restenosis, and death) was obtained in 207 patients. During the 2-year follow-up period, 72 patients--36 in the high-dose and 36 in the low-dose aspirin group, respectively--developed angiographically verified reobstruction within the recanalized segment. By intention-to-treat analysis, the cumulative patency rates at 24 months were 62.5% in the high-dose and 62.6% in the low-dose aspirin group (Wilcoxon, P = .97; log-rank, P = .97). The cumulative survival at 24 months of follow-up was 86.6% in the high-dose and 87.7% in the low-dose aspirin group. The number of patients discontinuing therapy was 30 in the high-dose and 11 in the low-dose aspirin group (P < .01). Fewer patients receiving 100 mg of aspirin discontinued therapy because of gastrointestinal symptoms (4 versus 20).

CONCLUSIONS

The data indicate that 100 mg aspirin is no less effective in the prevention of restenosis after femoropopliteal PTA than a 1000-mg dose and has fewer side effects.

Dobutamine-atropine stress echocardiography for assessment of perioperative and late cardiac risk in patients undergoing major vascular surgery

OBJECTIVE

To determine the value of dobutamine-atropine stress echocardiography and clinical variables to predict perioperative and late cardiac events in patients scheduled for elective major non-cardiac vascular surgery.

DESIGN

Blinded prospective study.

PATIENTS

Patients (n = 187 mean age 69 yrs).

MEASUREMENTS

Dobutamine-atropine stress test was performed preoperatively. Results were not used for clinical management. The clinical risk profile was evaluated by Detsky's score.

RESULTS

Technically adequate images were obtained in 185/187 patients, one major complication occurred (ventricular fibrillation) and four tests were prematurely stopped due to side effects. Data from 181 patients were analysed. The stress test was positive (new or worsened wall motion abnormality) in 56/181 patients. Perioperative cardiac events were: five fatal myocardial infarctions, three non-fatal myocardial infarctions, nine unstable angina pectoris and one pulmonary edema. All patients with a cardiac event had a positive stress test (18/56). No event occurred in patients with a negative stress test. By multivariate analysis only a new wall motion abnormality during the stress test (odds ratio 45.0, 6-369) was a significant predictor of cardiac events. Patients (n = 154) were followed after operation for 16 +/- 9 months. Twenty-four cardiac events occurred in 21 patients: six fatal myocardial infarctions, three non-fatal myocardial infarctions, six unstable angina pectoris, three ventricular arrhythmias and six congestive heart failures. The stress echo was positive in 19/21 patients with late cardiac events. The cardiac events correlated by multivariate analysis with a history of myocardial infarction (odds ratio 9.6, 1.9-47.7) and new wall motion abnormalities (odds ratio 6.2, 1.5-25.1).

CONCLUSION

Dobutamine-atropine stress echocardiography is a relatively safe and useful test to identify patients at risk of perioperative and late postoperative cardiac events.

Relative mortality of patients operated for femoropopliteal occlusive disease

The postoperative survival of 410 patients operated for femoropopliteal occlusive disease was evaluated retrospectively. Claudicants and patients operated for critical ischaemia were separated by age and their relative mortality compared. The relative mortality risk based on standard mortality rate calculations was estimated by relating observed survival to age and sex adjusted expected survival rates. The statistical differences in observed mortality from the expected was assessed using the Mantel-Haenszel test, and a proportional-hazard test, based on a multiplicative model, was employed to compare differences in relative mortality risk. The five-year observed and expected survival for all patients was 59 and 78% respectively, indicating a doubled risk of mortality. No conspicuous differences were found between males and females. Patients operated on for intermittent claudication were significantly younger and lived significantly longer than those with critical ischaemia. There was, however, no difference in relative mortality risk for the two groups. Claudicants younger than 70 years lived longer than the older patients, but there was no difference in relative death risk for the two groups. Patients operated on for critical ischaemia showed similar mortality for younger and older patients but the younger patients had a three to four times higher relative risk of mortality compared to the older.

Dobutamine stress echocardiography for assessment of perioperative cardiac risk in patients undergoing major vascular surgery

BACKGROUND

The purpose of this study was to determine the predictive value of dobutamine stress echocardiography for perioperative cardiac events in patients scheduled for elective major noncardiac vascular surgery.

METHODS AND RESULTS

Patients (n = 136; mean age, 68 years) unable to exercise underwent a dobutamine stress test before surgery (incremental dobutamine infusion [10-40 micrograms.kg-1.min-1] continued with atropine [0.25-1 mg i.v.] if necessary to achieve 85% of the age-predicted maximal heart rate without symptoms or signs of ischemia). The clinical risk profile was evaluated by Detsky's modification of Goldman's risk factor analysis. Echocardiographic images were evaluated by two observers blinded to the clinical data of the patients, and results of the test were not used for clinical decision making. Technically adequate images were obtained in 134 of 136 patients, one major complication occurred (ventricular fibrillation), and three tests were discontinued prematurely because of side effects. Finally, data from 131 patients were analyzed with univariate and multivariate methods. The dobutamine stress test was positive (new or worsened wall motion abnormality) in 35 of 131 patients. In the postoperative period, five patients died of myocardial infarction, nine patients had unstable angina, and one patient developed pulmonary edema. All patients with cardiac complications (15 patients) had a positive dobutamine stress test. No cardiac events occurred in patients with negative tests. Five patients with a technically inadequate or prematurely stopped test were operated on without complications. By multivariate analysis (logistic regression), only age > 70 years and new wall motion abnormalities during the dobutamine test were significant predictors of perioperative cardiac events.

CONCLUSIONS

Dobutamine stress echocardiography is a feasible, safe, and useful method for identifying patients at high or low risk of perioperative cardiac events. The test yields additional information, beyond that provided by clinical variables, in patients who are scheduled for major noncardiac vascular surgery.