Sex differences in perioperative and long-term cardiac event-free survival in vascular surgery patients. An analysis of clinical and scintigraphic variables

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.

The role of myocardial perfusion imaging in special populations: women, diabetics, and heart failure

Cardiovascular disease and its manifestations remain a major worldwide public health problem. Despite significant advances in diagnosis and treatment, coronary artery disease remains the leading cause of death of men and women in the developed world. Early and accurate diagnosis of coronary artery disease is crucial if men and women are to have improved outcomes. The continuous and dramatic growth in the field of nuclear cardiology during the past 2 decades has accounted for its central role in the clinical evaluation of patients with known or suspected coronary heart disease. The development of electrocardiogram-gated single photon emission tomography has facilitated the expansion of nuclear cardiology studies from the evaluation of myocardial perfusion alone to the evaluation of both perfusion and ventricular function data in a single study. Myocardial perfusion imaging with electrocardiogram-gated single photon emission tomography, with its ability to provide information about the physiologic significance of coronary stenosis, left ventricular function, and risk assessment of patients with coronary artery disease, is ideally suited for the diagnostic and prognostic evaluation of the patient who is at high to intermediate risk for ischemic heart disease.

The clinical role of stress myocardial perfusion imaging in women with suspected coronary artery disease

Cardiovascular disease remains the number one cause of mortality for women in the United States, with coronary artery disease (CAD) accounting for 54% of all cardiovascular deaths. CAD claims the lives of more than 250,000 women each year and is therefore the single largest killer of American women. For several decades, the under-representation of women in clinical trials led to both a lack of available sex-specific evidence and a generalized misconception that CAD was a "man's disease." In actuality, not only are women vulnerable to CAD, they typically develop it 10 to 15 years later than men. Furthermore, sex differences exist in the mortality rates of women and men with CAD, such that once CAD is present in women, they have worse outcomes than their male counterparts. Consequently, early and accurate diagnosis of CAD is crucial for reducing mortality rates in women. Stress myocardial perfusion imaging (MPI) using contemporary techniques has been shown to have significant value in the diagnosis and prognosis of CAD in women. In the risk assessment of women with an intermediate clinical pretest likelihood of CAD, using MPI with exercise or pharmacologic stress has been shown to add incremental value to clinical variables or exercise electrocardiogram stress testing alone. This review discusses the clinical role of stress MPI in the management of women with suspected CAD.

Stress Myocardial Perfusion Imaging in the Diagnosis and Prognosis of Women with Suspected Coronary Artery Disease

Coronary artery disease is the single largest killer of women in the United States and claims the lives of more than 250,000 women each year. For several decades, there was the misperception that coronary artery disease was a "man's disease." The fact is that women are indeed vulnerable to coronary artery disease; however, they typically develop the disease 10 to 15 years later than men. Once coronary artery disease is evident, women have worse outcomes as compared with men.Therefore, early and accurate diagnosis of coronary artery disease is crucial for reducing heart disease mortality in women. Stress myocardial perfusion imaging using contemporary techniques has been shown to have significant value in the diagnosis and prognosis of coronary artery disease in women. Myocardial perfusion imaging with exercise or pharmacologic stress has been shown to add incremental value to the use of clinical variables or exercise electrocardiogram stress testing alone in the risk stratification of women with an intermediate clinical pretest likelihood of coronary artery disease. This review provides an overview of the role of stress myocardial perfusion imaging in the clinical evaluation of women with suspected coronary artery disease.

Infrainguinal arterial reconstruction: female gender as risk factor for outcome

OBJECTIVES

the effect of gender on the long-term results of infrainguinal arterial reconstruction are poorly investigated.

METHODS

all patients undergoing infrainguinal arterial reconstruction with an autogenous vein are as 11 years period was prospectively evaluated.

RESULTS

four hundred and fifty reconstructions (292 man, 160 women) were performed as on 416 patients. Thirty-day mortality was 1.1% (n=5). Women were on average older (74 vs 68; p<0.001) and disease was more advanced (81 vs 68%,p =0.013 with stage of critical ischaemia). Primary (58 vs 61%) and primary assisted patency rates (82 vs 84%) were comparable. Limb salvage and survival after 60 months were not different. On multivariate analysis age and stage of the disease were independent variables for patency and survival. Diabetes and gender reached statistical significance as predictors of limb salvage only.

CONCLUSION

age and stage of the disease were independent predictors for patency and survival, diabetes and gender for limb salvage.

Cardiac imaging in women: use of radionuclide myocardial perfusion imaging and echocardiography for acute chest pain

Evidence for the value of noninvasive cardiac imaging in patients for the detection of ischemic heart disease has traditionally come from trials using male patients. The application of such technology for women is often presumptive. Because there is an overall lower prevalence of ischemic heart disease in women, difference in body habitus, and smaller heart size, cardiac imaging in women presents unique challenges for imaging specialists and cardiologists. With the introduction of technetium-99 meters perfusion agents, gated single-photon emission computed tomography, and attenuation correction, myocardial perfusion imaging (MPI) in women has achieved a high sensitivity and specificity for the detection of coronary artery disease similar to that observed in men. With harmonic imaging and myocardial contrast agents, two-dimensional echocardiography offers comparable diagnostic accuracy in women. More importantly, MPI and stress echocardiography have prognostic value in predicting future cardiovascular events. The severity and extent of the single-photon emission computed tomography myocardial perfusion defects independently predict future cardiovascular events. Myocardial perfusion rest imaging during acute chest pain has a 99% negative predictive value of subsequent cardiovascular events, and a positive study MPI is the most important predictor for future cardiac events. Both MPI and stress echocardiography can direct high-risk patients to more invasive management or selectively identify lower-risk patients, allowing safe discharge from the emergency department and unnecessary hospitalization. Using a triage approach incorporating MPI or rest echocardiography in patients with acute chest pain results in significant cost savings. However, data on rest imaging in women during acute chest pain are still lacking.

Long-term prognostic value of dipyridamole echocardiography in vascular surgery: a large-scale multicenter study

BACKGROUND

Late cardiac events after non-cardiac major vascular surgery are an important cause of morbidity and mortality. The aim of the present study was to assess the value of a preoperative dipyridamole echocardiography test (up to 0.84 mg/kg over 10 min) in predicting late cardiac events in survivors of major non-cardiac vascular surgery.

DESIGN

Large-scale, multicenter, prospective, observational study design.

METHODS

Two hundred and seventy-six patients (mean age 66 +/- 9 years) were studied prior to vascular surgery by dipyridamole stress echocardiography in four different centres. All patients underwent preoperative clinical risk assessment according to the American Heart Association guidelines. All underwent dipyridamole stress echocardiography according to standard high-dose protocol.

RESULTS

No major complications occurred during dipyridamole stress echocardiography. Sixty-three patients (23%) had a positive test. Patients were followed up for a median of 20 months. Cardiac events occurred in 43 patients (16%): five deaths, 18 myocardial infarctions and 20 cases of unstable angina. The difference between wall-motion score index (WMSI) at rest and peak stress (delta WMSI), using multivariate analysis, was an independent predictor of late cardiac death.

CONCLUSION

Dipyridamole stress echocardiography performed before major vascular surgery identifies patients at high risk for late cardiac events. Stress echocardiographic parameters outperformed clinical variables in the long-term risk stratification in this set of patients.

Gender does not impact infrainguinal vein bypass graft outcome

BACKGROUND

The percentage of women requiring infrainguinal bypass graft operations continues to increase, whereas the effect of gender on postoperative outcome remains unclear. The purpose of this study was to assess the influence of gender on patient selection and outcome in patients requiring infrainguinal vein bypass grafting procedures.

METHODS

This retrospective study reviewed 217 infrainguinal vein bypass grafts performed over an 8-year period. Medical records and patient interviews were used to determine study measures and outcomes. Gender and multiple covariables affecting patient survival were analyzed; postoperative complications and graft patencies were examined. Bivariate and life-table analyses were conducted, followed by multivariate analysis with the Cox proportional hazards model.

RESULTS

No statistical differences existed between men and women for age, diabetes, cardiac disease, tobacco use, hypertension, stroke, renal disease, or prior contralateral bypass or major amputation. Women were more likely to be black (P =.014) and have a spliced vein graft (P =.035). No differences were noted between the 2 groups for 30-day morbidity rates-except women had more incisional complications (P =.01)-or for survival (P =.45), primary-patency (P =.57), secondary-patency (P =. 79), or limb-salvage rates (P =.40). Multivariate analysis showed that gender had no role in affecting survival rates.

CONCLUSIONS

Gender does not affect graft patency, limb salvage, or survival rates. There should be no introduction of a gender bias into management of infrainguinal occlusive disease.

Exercise equilibrium radionuclide angiography predicts long-term cardiac prognosis in patients with abdominal aortic aneurysm being considered for surgery

BACKGROUND

Patients with an abdominal aortic aneurysm (AAA) have a high prevalence of coronary disease and are at risk for cardiac events. This may offset the prognostic benefit of surgical repair. We investigated whether preoperative exercise equilibrium radionuclide angiography (ERNA) could be used to identify patients at high risk for cardiac events after successful AAA repair.

METHODS

Between 1990 and 1995, 173 patients with an AAA were referred for supine bicycle exercise ERNA preoperatively. Follow-up information was obtained from a questionnaire sent to each patient's family physician. Cardiac events were defined as cardiac death or nonfatal myocardial infarction.

RESULTS

A total of 139 patients were able to exercise and did not die or suffer myocardial infarction perioperatively. The median follow-up period was 3.8 years. Diabetes mellitus, an exercise ejection fraction (EF) below 0.50, and a fall in EF with exercise were univariable predictors of cardiac risk during the follow-up period (P < .05). On multivariable analysis, diabetes mellitus (risk ratio [RR], 6.9; 95% CI 1.5 to 32.0) and an EF fall (RR, 4.1; 95% CI 1.5 to 11.4) emerged as the most important predictors.

CONCLUSIONS

Exercise ERNA predicts long-term cardiac events in patients being considered for elective AAA repair. Such predictive information may influence the decision to operate, for example, on small unthreatening aneurysms, or lead to invasive cardiological management to minimize risk.

Estrogen replacement therapy and the surgeon

BACKGROUND

The number of patients over the age of 65 years has increased to 33.2 million, with a life expectancy of 76.5 years. With an aging population, the number of surgical procedures is expected to increase as much as 50%. The majority of individuals over 65 years are women. Estrogen replacement therapy is commonly recommended to postmenopausal women for relief of vasomotor symptoms, protection against heart disease, and prevention of osteoporosis.

PURPOSE

The purpose of this review is to address estrogen replacement therapy with regard to wound healing, fracture repair, perioperative cardiac morbidity, and thrombosis.

DATA SOURCE

Medline Literature review.

CONCLUSIONS

There is insufficient evidence to withdraw estrogen replacement therapy at the time of admission for surgery. Patients not receiving estrogen replacement therapy should be offered therapy upon return to ambulatory status.

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.

Cost analysis of diagnostic testing for coronary artery disease in women with stable chest pain. Economics of Noninvasive Diagnosis (END) Study Group

BACKGROUND

Seven clinical sites compiled data from 4638 women who were referred directly to coronary angiography (catheterization-first strategy; n = 3375) or who underwent stress myocardial perfusion imaging (MPI) first (n = 1263) followed by coronary angiography if at least one reversible myocardial perfusion abnormality was detected. The study examines the cost minimization potential of these available invasive and noninvasive diagnostic strategies in women with chest pain.

METHODS AND RESULTS

Women in both groups were subclassified by the core laboratory as being at low (<0.15), intermediate (0.15 to 0.60), or high (>0.60) pretest likelihood for coronary artery disease (CAD). Among the catheterization-first patients, at least one coronary stenosis >70% was present in 13% of low likelihood patients, 29% of intermediate likelihood patients, and 52% of patients with high CAD likelihood. Perfusion abnormality rates in the MPI-first group were 23% in low likelihood patients, 27% in intermediate likelihood patients, and 34% in high CAD likelihood patients. Of the MPI-first subset, 50%, 55%, and 76%, respectively, underwent catheterization in at least one coronary stenosis >70%. Cardiac death rates ranged from 0.5% to 2.2% in patients with CAD and did not differ from the 2 testing strategies (P = not significant). The composite cost per patient of diagnostic testing plus follow-up medical care over a period of 2.5 +/- 1.5 years (calculated for both strategies from inflation-corrected Medicare charges, adjusted for institutional cost-charge ratios) ranged from $2490 for patients with low likelihood to $3687 for patients with high likelihood with the catheterization-first strategy and from $1587 to $2585 for patients undergoing MPI first (P < .01 between risk subsets and strategies).

CONCLUSIONS

In women referred for diagnostic evaluation of stable chest pain, MPI followed by selective coronary angiography in patients with at least 1 perfusion abnormality minimizes the near-term composite cost per patient compared with a direct catheterization-first strategy, regardless of pretest CAD likelihood.

Women have increased risk of perioperative myocardial infarction and higher long-term mortality rates after lower extremity arterial bypass grafting

PURPOSE

The purpose of this study was to determine the effect of gender on the immediate and long-term postoperative morbidity, mortality, and patency rates for infrainguinal autogenous vein bypass grafts.

METHODS

Data were abstracted for consecutive patients who were followed in a prospective surveillance protocol after undergoing infrainguinal autogenous vein bypass grafting during the years 1988 to 1994. There were 165 grafts constructed in 148 patients (101 in 87 men, and 64 in 61 women). Gender differences were analyzed with Student t test or chi2 test for risk factors, indications for reconstruction, and complications. The patency rates and the long-term survival rates were compared by means of life-table analysis. Eagle criteria and long-term survival rates were compared with multivariate analysis.

RESULTS

The mean follow-up period was 36 months (39 months for men, and 32 months for women), with a range of 6 to 123 months for the total follow-up period. The two groups did not differ in age at the time of operation (66.6 +/- 1.2 years for men, and 66.7 +/- 1.5 years for women) or in history of diabetes (48% for men, and 56% for women). The risks were similar for hypertension (48% for men vs 45% women), preoperative myocardial infarction (23% for men vs 26% for women), and previous coronary artery bypass grafting (9% for men vs 8% for women). The thallium stress scintigraphy results showed a diagnosis of proportionately more preoperative defects in men (reversible, 34% vs 18%, P <.05; overall, 75% vs 43%, P <.05). The 30-day limb loss rates (0.9% for men, and 0% for women) and mortality rates (2.2% for men, and 5% for women) were similar. Women had statistically more perioperative myocardial infarctions than did men (6 of 61, 9.8% vs 2 of 101, 2%; P <.05), as was documented with electrocardiography and cardiac isoenzymes. Two of these women died within a 30-day postoperative period. The 3-year primary patency rate was 85% for the men and 88% for the women, and the primary assisted patency rate was 97% for the men and 97% for the women. The secondary patency rate was 98% for the men and 97% for the women. The limb salvage rate was slightly higher for the men than for the women (93% vs 87%), although this was not statistically significant. The 5-year survival rate for women was statistically less than for men, with life-table analysis (58% for men vs 42% for women; P <.05).

CONCLUSION

After distal bypass grafting, men and women have similar rates of patency and limb salvage, but women have a higher incidence rate of perioperative myocardial infarction and a decreased 5-year survival rate. These data suggest that women have unrecognized cardiac disease that affects them adversely in the perioperative period and the long term when compared with men who undergo the same operation.

Dipyridamole thallium-201 single-photon emission computed tomography for prediction of perioperative cardiac events in patients with arteriosclerosis obliterans undergoing vascular surgery

The aim of the study was to determine whether or not dipyridamole thallium-201 single-photon emission computed tomography (201Tl-SPECT) has significant additive value for predicting perioperative cardiac events in patients with arteriosclerosis obliterans (ASO) undergoing vascular surgery. Routine preoperative 201Tl-SPECT was performed in 106 consecutive patients with ASO (age 68+/-8.9 years; 91 men and 15 women). The frequency of reversible defects in a clinical high-risk group (n=44) was significantly higher than in a low-risk group (n=62; 55% vs 24%, p<0.01). Perioperative cardiac events occurred in 9 patients, including 4 cardiac deaths, 1 non-fatal myocardial infarction, and 4 cases of unstable angina. Although clinical risk stratification was useful in predicting cardiac events (19% in the high-risk group vs 2% in the low-risk group, p<0.01), the positive predictive value was low. When considering a combination of 2 or more than 2 risk factors and a large reversible defect as a predictor, the positive predictive value and specificity increased from 19% to 47% and from 64% to 91%, respectively, whereas the sensitivity remained unchanged (89%). These results suggest that the addition of 201Tl-SPECT data to clinical risk-stratified patients with ASO allows better prediction of perioperative cardiac events.

Perioperative cardiac evaluation for noncardiac surgery noninvasive cardiac testing

Prognostic risk stratification to identify perioperative and long-term cardiac risk in selected patients undergoing noncardiac surgery is part of good clinical practice. Exercise variables associated with significant increased risk include poor functional capacity (eg, <4 metabolic equivalents), marked exercise-induced ST segment shift or angina at low workloads, and inability to increase or actually decrease systolic blood pressure with progressive exercise. Approximately 40% of patients tested before peripheral vascular surgery will have an abnormal exercise electrocardiogram (ECG). The predictive value for a perioperative event, ie, death or myocardial infarction, ranges from 5% to 25% for a positive test and 90% to 95% for a negative test. Whereas exercise cardiac imaging is the modality of choice in patients with a noninterpretable exercise ECG, pharmacological stress imaging should be used in the 30% to 50% of patients who require perioperative noninvasive risk stratification and are unable to perform an adequate level of exercise to test cardiac reserve. Myocardial perfusion variables predictive of increased cardiac events include severity of the perfusion defect, number of reversible defects, extent of fixed and reversible defects, increased lung uptake of thallium-201, and marked ST segment changes associated with angina during the test. The reported sensitivity and specificity of dobutamine-induced echocardiographic wall motion abnormalities in patients with peripheral vascular disease is similar to myocardial perfusion scintigraphy, but the confidence limits are wider due to the smaller sample size in these more recent studies. In conclusion, noninvasive cardiac testing should be used selectively in patients undergoing noncardiac surgery; the results provide useful estimates of short- and long-term risk of cardiac events, and the magnitude of abnormal response on noninvasive testing should be used to formulate decisions regarding the need for coronary angiography and subsequent revascularization.

Comparison of defect size between thallium-201 and technetium-99m tetrofosmin myocardial single-photon emission computed tomography in patients with single-vessel coronary artery disease

Defect size on exercise-rest technetium (Tc)-99m tetrofosmin myocardial perfusion imaging was compared with that on exercise-reinjection thallium-201 imaging with 20 patients with 1-vessel coronary artery disease. In each patient, exercise-reinjection thallium-201 single-photon emission computed tomography (SPECT) and exercise-rest Tc-99m tetrofosmin SPECT imaging were performed. For visual analysis of the obtained SPECT images, the left ventricular myocardium was divided into 20 segments based on 3 short-axis slices from the apical, middle, and basal ventricular levels. For quantitative analysis, a square region of interest was placed on the center of each segment which was used for visual analysis, and relative regional activity to the normal reference region was calculated for each segment. By visual interpretation of the images, exercise Tc-99m tetrofosmin imaging showed a smaller defect size than exercise thallium-201 imaging (6.9 +/- 3.9 vs 8.8 +/- 3.0 segments, p <0.01). In contrast, rest Tc-99m tetrofosmin imaging showed a defect size similar to that on reinjection thallium-201 imaging (5.9 +/- 3.6 vs 5.6 +/- 3.9 segments, p = NS). Similarly, the mean defect sizes during exercise determined by quantitative analysis were smaller on Tc-99m tetrofosmin SPECT than those on thallium-201 SPECT at all tested threshold cutoff points ranging from 50% to 70%, whereas there were no significant differences in defect sizes between rest Tc-99m tetrofosmin and reinjection thallium-201 imaging. These data indicate that exercise Tc-99m tetrofosmin SPECT defect size determined either by visual analysis or by quantitative analysis may be smaller than on exercise thallium-201 SPECT.

Additive value of thallium single-photon emission computed tomography myocardial imaging for prediction of perioperative events in clinically selected high cardiac risk patients having abdominal aortic surgery

The present study was designed to prospectively evaluate whether reinjection thallium-201 single-photon emission computed tomography (SPECT) has a significant additive predictive value for occurrence of perioperative cardiac events in clinically selected patients at high cardiac risk undergoing abdominal aortic surgery. Of a group of 517 consecutive patients referred, 134 had > or = 2 of the following clinical or electrocardiographic cardiac risk variables: age > 70 years; history of myocardial infarction, angina, or congestive heart failure; diabetes mellitus; hypertension with severe left ventricular hypertrophy; and Q waves or ischemic ST-segment abnormalities on electrocardiogram at rest. Operation was performed after thallium SPECT study. Twelve patients (9%) had major perioperative events (cardiac death or nonfatal myocardial infarction) and 18 patients had other cardiac events (unstable angina, congestive heart failure, or severe ventricular tachyarrhythmia). Variables correlated with the occurrence of major events were history of myocardial infarction (p < 0.05) and the presence (p < 0.001) and number of segments with thallium reversible defects (p < 0.001). In multivariate analysis, history of myocardial infarction (p < 0.05) and the number of segments with reversible thallium defects (p < 0.001) were independent predictors. When all the cardiac events were taken into consideration, all the previous variables, as well as Q waves and ischemic ST abnormalities on the electrocardiogram, showed significant predictive value in both univariate and multivariate analyses. Furthermore, thallium SPECT imaging has an additive predictive value for major cardiac events over clinical and electrocardiographic risk factors. When performed on clinically selected patients at high cardiac risk undergoing abdominal aortic surgery, thallium SPECT demonstrates significant prognostic value for cardiac events over that provided by clinical variables alone.