Postoperative myocardial infarction and cardiac death. Predictive value of dipyridamole-thallium imaging and five clinical scoring systems based on multifactorial analysis

Development and evolution of nuclear cardiology and cardiac PET in Canada

Gated radionuclide angiography and myocardial perfusion imaging were developed in the United States and Europe in the 1970's and soon adopted in Canadian centers. Much of the early development of nuclear cardiology in Canada was in Toronto, Ontario and was quickly followed by new programs across the country. Clinical research in Canada contributed to the further development of nuclear cardiology and cardiac PET. The Canadian Nuclear Cardiology Society (CNCS) was formed in 1995 and became the Canadian Society of Cardiovascular Nuclear and CT Imaging (CNCT) in 2014. The CNCS had a major role in education and advocacy for cardiovascular nuclear medicine testing. The CNCS established the Dr Robert Burns Lecture and CNCT named the Canadian Society of Cardiovascular Nuclear and CT Imaging Annual Achievement Award for Dr Michael Freeman in memoriam of these two outstanding Canadian leaders in nuclear cardiology. The future of nuclear cardiology in Canada is exciting with the expanding use of SPECT imaging to include Tc-99m-pyrophosphate for diagnosis of transthyretin cardiac amyloidosis and the ongoing introduction of cardiac PET imaging.

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

Background

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

Methods

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

Results

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

Conclusions

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

Is Preoperative Cardiac Testing Indicated Prior to Elective Carotid Endarterectomy?

The high incidence of coronary artery disease in patients with peripheral and cerebrovascular occlusive disease has been well established. While preoperative cardiac evaluation has been shown to be beneficial in patients undergoing elective aortic reconstruction, the role of preoperative cardiac testing in patients undergoing elective carotid endarterectomy has not been defined. In this study, the charts of 289 consecutive patients undergoing elective carotid endarterectomy between January 1, 1995, and December 31, 1995, were evaluated to determine the need for cardiac “clearance” prior to surgery. Ages ranged from 48 to 98, with a mean of 70.4 years. The male-to-female ratio was 165:124. Risk factors for coronary artery disease were also assessed: 203 patients (70%) were hypertensive, and 162 patients (56%) gave a history of smoking. An abnormalappearing preoperative EKG was identified in 139 patients (48%). Sixty-seven patients (23%) presented with a history of angina pectoris, and 80 patients (28%) had sustained a myocardial infarction in the past. No patient presented with unstable angina or angina at rest. No patient underwent coronary artery bypass grafting or coronary artery angioplasty immediately prior to carotid endarterectomy. Of the 289 endarterectomies 154 (53%) were performed under regional anesthesia. All patients were monitored with intraoperative arterial pressure catheters. There were no postoperative deaths. No patient sustained a documented postoperative myocardial infarction. One patient experienced chest pain for 24 hours postoperatively. This patient had a history of angina pectoris and a previous myocardial infarction. One patient had an episode of shortness of breath postoperatively. There were two postoperative strokes. These data suggest that patients with known or suspected coronary artery disease can safely undergo elective carotid endarterectomy without extensive cardiac testing prior to surgery.

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.

Hypertension, hypertensive heart disease and perioperative cardiac risk †

The evidence for an association between hypertensive disease, elevated admission arterial pressure, and perioperative cardiac outcome is reviewed. A systematic review and meta-analysis of 30 observational studies demonstrated an odds ratio for the association between hypertensive disease and perioperative cardiac outcomes of 1.35 (1.17-1.56). This association is statistically but not clinically significant. There is little evidence for an association between admission arterial pressures of less than 180 mm Hg systolic or 110 mm Hg diastolic and perioperative complications. The position is less clear in patients with admission arterial pressures above this level. Such patients are more prone to perioperative ischaemia, arrhythmias, and cardiovascular lability, but there is no clear evidence that deferring anaesthesia and surgery in such patients reduces perioperative risk. We recommend that anaesthesia and surgery should not be cancelled on the grounds of elevated preoperative arterial pressure. The intraoperative arterial pressure should be maintained within 20% of the best estimate of preoperative arterial pressure, especially in patients with markedly elevated preoperative pressures. As a result, attention should be paid to the presence of target organ damage, such as coronary artery disease, and this should be taken into account in preoperative risk evaluation. The anaesthetist should be aware of the potential errors in arterial pressure measurements and the impact of white coat hypertension on them. A number of measurements of arterial pressure, obtained by competent staff (ideally nursing staff), may be required to obtain an estimate of the "true" preoperative arterial pressure.

Cardiac nuclear medicine in monitoring patients with coronary heart disease

Patient monitoring is a major indication for cardiac nuclear medicine procedures. Stress myocardial perfusion scintigraphy was initially used for diagnosis, but monitoring patients with coronary artery disease has become more common. Stress myocardial perfusion scintigraphy has been shown to provide a considerable amount of incremental prognostic information, which may be useful in selecting patients for therapy. In patients being considered for revascularization, fluorodeoxyglucose can be used to identify regions of dysfunctional but viable myocardium, even within regions that show fixed defects on stress perfusion imaging. It can be used to select a group of patients who will improve function with revascularization and who may have an improved outcome. Thus, cardiac nuclear medicine plays a pivotal role in monitoring patients with coronary artery disease.

An abnormal dipyridamole thallium/sestamibi fails to predict long-term cardiac events in vascular surgery patients

Recent data demonstrate that dipyridamole-thallium (DTHAL) and sestamibi (DMIBI) are not predictive of adverse perioperative cardiac events in moderate-risk patients (one or more Eagle risk factors) undergoing major elective vascular surgery. Less data are available regarding the ability of DTHAL/DMIBI to predict adverse cardiac events on long term follow-up. We sought to determine whether an abnormal DTHAL/DMIBI is predictive of adverse cardiac events on long-term follow-up in moderate-risk patients undergoing major elective vascular surgery. Patients were enrolled prospectively between June 1997 and June 1999 at West Los Angeles VA and Harbor-UCLA Medical Centers. Adverse cardiac events were defined as congestive heart failure (CHF), myocardial infarction (MI), unstable angina (USA), and ventricular arrhythmias. Follow-up was obtained via clinic visits, telephone calls, and chart review. We studied 75 patients (76% male, 24% female) with a mean age of 65 years. Operative procedures were primarily femorodistal (83%) and aortic (16%). DTHAL/DMIBI results were normal in 35 patients (47%), demonstrated reversible ischemia in 26 (35%), and showed a fixed defect alone in 14 (18%). From the follow-up results of this study we conclude that there is no association between a reversible ischemia or an abnormal (fixed or reversible) DTHAL/DMIBI and adverse cardiac events or mortality on long-term follow-up in moderate-risk patients who have undergone major vascular surgery.

Principal uses of myocardial perfusion scintigraphy in the management of patients with known or suspected coronary artery disease

The use of myocardial perfusion single photon emission computed tomography (SPECT) has undergone considerable expansion and evolution over the past 2 decades. Although myocardial perfusion imaging was first conceived as a noninvasive diagnostic tool for determining the presence or absence of coronary artery disease, its prognostic value is now well established. Thus, identification of patients at risk for future cardiac events has become a primary objective in the noninvasive evaluation of patients with chest pain syndromes and among patients with known coronary artery disease. In particular, the ability of myocardial perfusion SPECT to identify patients at low (< 1%), intermediate (1% to 5%) or high (> 5%) risk for future cardiac events is essential to patient management decisions. Moreover, previous studies have conclusively shown the incremental prognostic value of myocardial perfusion SPECT over clinical and treadmill exercise data in predicting future cardiac events. This report addresses the current role and new developments, with respect to the use of myocardial perfusion imaging, in determining patient risk for cardiac events and the cost-effective integration of such information into patient management decisions.

Dipyridamole-thallium/sestamibi before vascular surgery: a prospective blinded study in moderate-risk patients

PURPOSE

This study assessed in a prospective, blinded fashion whether a reversible defect on dipyridamole-thallium (DTHAL)/sestamibi (DMIBI) can predict adverse cardiac events after elective vascular surgery in patients with one or more clinical risk factors.

METHODS

Consecutive patients with one or more clinical risk factors underwent a preoperative blinded DTHAL/DMIBI. Patients with recent congestive heart failure (CHF) or myocardial infarction (MI) or severe or unstable angina were excluded.

RESULTS

Eighty patients (78% men; mean age, 65 years) completed the study. Diabetes mellitus was the most frequent clinical risk factor (73%), followed by age older than 70 years (41%), angina (29%), Q wave on electrocardiogram (26%), history of CHF (7%), and ventricular ectopy (3%). The results of DTHAL/DMIBI were normal in 36 patients (45%); a reversible plus or minus fixed defect was demonstrated in 28 patients (36%), and a fixed defect alone was demonstrated in 15 patients (19%). Nine adverse cardiac events (11%) occurred, including three cases of CHF, and one case each of unstable angina, Q wave MI, non-Q wave MI, and cardiac arrest (successfully resuscitated). Two cardiac deaths occurred (2% overall mortality), one after a Q wave MI and one after CHF and a non-Q wave MI. The cardiac event rate was 14% for reversible defect and 9.8% without reversible defect (P =.71). The cardiac event rate was 12.5% (one of eight cases) for two or more reversible defects, versus 11.1% (eight of 72 cases) for fewer than two reversible defects (P = 1.0). The sensitivity rate of two or more areas of redistribution was 11% (95% CI, 0.3%-48%), the specificity rate was 90%, and the positive and negative predictive values were 12.5% and 89%, respectively.

CONCLUSION

Our study demonstrated no association between reversible defects on DTHAL/DMIBI and adverse cardiac events in moderate-risk patients undergoing elective vascular surgery.

Preoperative assessment of cardiac risk in noncardiac major vascular surgery

We evaluated whether a preoperative clinical algorithm allows an adequate stratification in cardiac risk and the predictive value of dipyridamole thallium-201 scintigraphy and rest echocardiography for postoperative adverse cardiac outcomes. Three hundred twenty patients undergoing 338 vascular surgery procedures were prospectively stratified into low, intermediate, and high risk. The low- and intermediate-risk patients underwent surgery without further diagnostic evaluation. In 7 high-risk patients the vascular procedure was canceled (1 died of myocardial infarction at 6-month follow-up), 9 underwent presurgical myocardial revascularization (1 died of myocardial infarction), and 49 underwent vascular surgery with perioperative intensive care treatment. Hospital mortality was 3.8%. Cardiac mortality and morbidity were 1.5% and 10.4%, respectively. We observed a significant difference in "hard" (death, myocardial infarction, pulmonary edema, major arrhythmias) and "soft" (myocardial ischemia, minor arrhythmias) events between groups, p <0.001. Previous pulmonary edema was a predictive variable of cardiac outcomes (multiple logistic regression analysis). Ninety-nine of 220 intermediate-risk patients randomly underwent dipyridamole thallium-201 scintigraphy: 37 had redistribution, 10 persistent, and 52 no defects; 7 of 13 soft and hard cardiac events occurred in patients without redistribution defects. Sensitivity, specificity, and positive and negative predictive values of redistribution defects for postoperative adverse outcomes were 38%, 63%, 14%, 87%, respectively. This algorithm may provide a safe and cost-effective approach (average cost saving per patient $1,500) to cardiac risk stratification. These results suggest that routine use of dipyridamole thallium-201 scintigraphy for screening of intermediate-risk patients may not be warranted.

Elective surgery for gastrointestinal tumours in the elderly

The geriatric population is expanding and clinical decision-making is often complicated by the effects of ageing. Age should not be the only parameter considered when addressing medical problems. Elderly subjects have been denied surgery because of their presumed higher mortality and morbidity. The present review summarises the physiology of the aged and discusses operative risks, mortality and morbidity rates as well as therapeutic results for the different gastrointestinal sites when affected by cancer. Reports on surgical treatments are revisited and compared to the same procedures delivered to younger patients in the context of the ethical issue of offering the best care to every patient. Elective operations by surgical oncologists are found to be safe with the exception of major liver resections. Complication rates and mean hospital stay do not differ between the two age groups provided the procedure is conducted with the best-known technique in expert hands. A drop in operative morbidity has occurred in the past three decades. Several investigators have emphasised the marked increase in morbidity and mortality experienced by elderly patients when undergoing emergency procedures. Associated diseases have to be properly assessed, as the elderly have a frail physiological balance with a reduced capacity for recovery from traumatic events including major surgical procedures. Careful preoperative evaluation, intraoperative conduct and postoperative care are presently achieved in almost every major hospital. Good clinical practice is based on the balance between probability of cure and toxic effects. Treatment of the elderly should no longer be based on untested beliefs and personal opinions. The elderly should be accrued for prospective clinical evaluation and should not be denied optimal surgical treatment.

Prognostic value of myocardial perfusion imaging: state of the art and new developments

Although the prognostic value of myocardial perfusion imaging is now well established, new data have continued to expand its role in the management of patients. This review addresses the current state-of-the-art and new developments in the use of myocardial perfusion imaging for determining cardiac risk and integrating such information into patient care.

Myocardial perfusion scintigraphy in patients undergoing major non-vascular abdominal surgery

The prognostic value of myocardial perfusion scintigraphy is beginning to be recognised in patients undergoing cardiovascular surgery. The aim of this prospective study was to assess the predictive value of scintigraphy in elderly patients undergoing major non-vascular abdominal surgery. Adenosine stress thallium-201 (201Tl) single-photon emission tomography (SPET) was employed for imaging using a standard protocol. Patients over the age of 60 years (n = 55) with an intermediate to high likelihood of coronary artery disease were evaluated prospectively. The clinical outcome variables analysed were cardiac mortality and major cardiac morbidity occurring within 30 days of surgery. Cardiac events were cardiac death (n = 5), angina pectoris (n = 5), nonfatal mycardial infarction (n = 1), acute left ventricular failure (n = 2) and arrhythmias requiring treatment (n = 4). All cardiac events occurred in the first 10 postoperative days except one cardiac death which happened on the 29th postoperative day. Patients with an abnormal 201Tl SPET scan had a higher risk of postoperative death (4 vs 1) or any postoperative cardiac event (13 patients vs 4 patients; P < 0.0001) when compared with those with a normal scan. The sensitivity, specificity and positive predictive value of 201Tl imaging for perioperative ischaemia and adverse outcomes were 76%, 82% and 65%, respectively. The occurrence of an intraoperative event (P < 0.02) and the length of surgery (P < 0.01) were also predictors of a postoperative cardiac event. Clinical risk variables and an abnormal electrocardiogram in isolation were poor predictors. In conclusion, preoperative myocardial perfusion scintigraphy is a valuable technique for identifying elderly patients with a high risk for cardiac events when undergoing major non-vascular abdominal surgery.

Cardiac evaluation of the diabetic patient prior to peripheral vascular surgery

The benefit of preoperative cardiac evaluation in the diabetic patient undergoing peripheral vascular surgery is uncertain. To investigate this issue we performed a retrospective review of 192 procedures performed in diabetic patients for chronic lower extremity arterial occlusive disease. The incidence of adverse postoperative cardiac events was determined, as well as its association with several preoperative factors including symptoms of coronary artery disease (CAD), extent and results of preoperative noninvasive cardiac evaluation, and operative site (aorta vs. lower extremity). The overall death and cardiac complication rates were 10.2% for lower extremity and 25.7% for aortic procedures (p = 0.02). For myocardial infarction and cardiac death alone, the rates were 5.1% and 5.7%, respectively (p > 0.10). Although a history of symptomatic CAD predicted the occurrence of any cardiac complication (28.3% vs. 8.2% [p < 0.01] for the aortic and lower extremity revascularization groups combined), no factor was found to be associated with the occurrence of myocardial infarction and cardiac death alone. In patients with a history of symptomatic CAD, there was no significant difference in the incidence of complications whether or not preoperative noninvasive cardiac testing was performed (28.1% vs. 28.6%, p > 0.10) or, if testing was performed, if the results were abnormal or normal (35.3% vs. 20.0%, p > 0.10). Similar results were obtained in patients with no history of symptomatic CAD. In summary, this retrospective review of our experience with noninvasive evaluation to detect CAD in diabetic patients undergoing peripheral vascular surgery failed to show any benefit in terms of reducing the incidence of postoperative cardiac events.

Meta-analysis of intravenous dipyridamole-thallium-201 imaging (1985 to 1994) and dobutamine echocardiography (1991 to 1994) for risk stratification before vascular surgery

OBJECTIVES

This study evaluated the prognostic value of abnormal test results with pharmacologic stress with regard to perioperative and long-term outcomes in a large population of candidates for vascular surgery.

BACKGROUND

Although numerous studies have demonstrated the prognostic value of dipyridamole-thallium-201 myocardial perfusion and dobutamine echocardiography in vascular surgery candidates, a synopsis of predictive estimates is difficult because of individual study variability in pretest clinical risk, sample size and study design.

METHODS

A systematic review of published reports on preoperative pharmacologic stress risk stratification from the MEDLINE data base (1985 to 1994) identified 10 reports on dipyridamole-thallium-201 myocardial perfusion (1,994 patients) and 5 on dobutamine stress echocardiography (446 patients). Random effects models were used to calculate summary odds ratios and 95% confidence intervals.

RESULTS

Summary odds ratios for death or myocardial infarction and secondary cardiac end points were greater for dobutamine echocardiographic dyssynergy (14- to 27-fold) than for dipyridamole-thallium-201 redistribution (4-fold); wider confidence intervals were noted with dobutamine echocardiography. Pretest coronary disease probability was correlated with the positive predictive value of a reversible thallium-201 defect (r=0.70), increasing sixfold from low to high risk patient subsets. Cardiac event rates were low in patients without a history of coronary artery disease (1% in 176 patients) compared with patients with coronary disease and a normal or fixed-defect pattern (4.8% in 83 patients) and one or more thallium-201 redistribution abnormality (18.6% in 97 patients, p=0.0001).

CONCLUSIONS

Meta-analysis of 15 studies demonstrated that the prognostic value of noninvasive stress imaging abnormalities for perioperative ischemic events is comparable between available techniques but that the accuracy varies with coronary artery disease prevalence.

Minimising cardiac anaesthetic risk: the tortoise or the hare?

There is no doubt that a group of patients at increased risk of peri-operative cardiac morbidity exists and must be managed with the emphasis on the prevention of myocardial ischaemia. It is also clear that a potentially far larger group are at risk of failing to meet the increased cardiovascular and metabolic demands of surgery and therefore suffering the consequences of a relative hypoperfusion injury. Pre-operative assessment must address both groups and management regimens sought to provide optimal outcome for both. At present there is no consistent strategy for their identification, assessment or management of the high risk surgical population despite the fact that they probably consume a disproportionate share of hospital resources. The first and most important step is the recognition that this high risk group exists. Only then can this population be given similar consideration to those currently thought to be at risk of ischaemia.

[Preoperative evaluation of coronary circulation]

To define a strategy for coronary circulation assessment is a difficult task as most of the studies have been carried out in vascular surgery, as some of them are controversial, and as no test has a 100% sensitivity and specificity. However patients with high perioperative risk of cardiac events have to be identified, in order to intensify medical treatment or to consider myocardial revascularisation. A first evaluation is based on history, physical examination and simple tests, such as rest electrocardiogram and thorax X-Ray. Additional tests are not required when surgery does not elicit a major activity of the cardiocirculatory system. Postoperative cardiac risk is low when none of the nine risk factors defined by Goldman and/or coronary insufficiency (residual angina elicited by minor physical activity, unstable angina, myocardial infarction) are present. The problem remains in patients with Goldman risk factors and/or at risk of coronary artery disease because of diabetes mellitus, heavy smoking, hypercholesterolaemia, arterial hypertension, undergoing major abdominal, thoracic or vascular surgery. Preoperative electrocardiographic Holter monitoring is still of value, especially in patients with known or supposed ischaemic heart disease and unable to make a physical effort. A poor exercise capacity and changes in electrocardiographic stress testing are factors of poor prognosis. The dobutamine stress echocardiography has a good sensitivity and specificity when an effort test cannot be performed. The value of dipyridamole-thallium 201 scintigraphy could be improved by a quantitative analysis of the number of affected segments and territories. Patients with angina or ischaemic episodes on continuous electrocardiogram, or with dobutamine echocardiography kinetic disturbances and with stress myocardic scintigraphy or stress exercise testing abnormalities could undergo a coronarography, in order to consider myocardic revascularization prior to surgery.

Routine coronary arteriography before abdominal aortic aneurysm repair

BACKGROUND

As cardiac complications constitute the principal cause of early and late morbidity and mortality after the surgical treatment of abdominal aortic aneurysm (AAA), a prospective study was planned to evaluate the effects of revascularization of coronary arteries on survival after AAA repair during early and long-term follow-up periods.

PATIENTS AND METHODS

A total of 125 patients underwent elective repair of AAA between 1986 and 1994. Coronary arteriography was performed in all cases. All cases with critical left anterior descending artery (LAD) lesions underwent a coronary artery bypass operation either simultaneously or shortly before AAA repair. In addition, percutaneous transluminal coronary angioplasty (PTCA) was performed for symptomatic and critical stenosis of arteries other than the LADs, or if noncritical but symptomatic stenosis of the LADs existed. Early and late follow-up data were obtained for all cases, and late-term cumulative survival rates were calculated.

RESULTS

Coronary artery lesions were found in 66 (53%) cases. In 24 cases, AAA repairs were performed 2.3 (mean) months after coronary artery bypass grafting (CABG), whereas in 4 cases both procedures were performed simultaneously. PTCA was performed in 4 cases 3 to 4 days prior to the abdominal surgery. Even though the coronary artery lesions were found inoperable in 7 cases, these patients underwent repair of AAA because of rapidly expanding and painful aneurysms. Early mortality rate was 4% (5 cases), in which 3 of these were from the group inoperable for CABG. A mean follow-up of 3.17 years (3 to 87 months) was achieved for all discharged patients. Cumulative survival rates for 6 months and 1, 2, 3, and 6 years were 99%, 99%, 95%, 93%, and 89%, respectively.

CONCLUSIONS

The results of this study emphasize the importance of coronary artery revascularization for early, and especially for late, survival after AAA repair.

Long-term risk stratification with dipyridamole imaging

This study was undertaken to assess the reliability of clinical parameters and dipyridamole-thallium 201 images for predicting the occurrence of future cardiac events (nonfatal myocardial infarction or cardiac death). Dipyridamole myocardial perfusion imaging is routinely performed in patients who have possible or known coronary disease and a low exercise tolerance. A total of 753 patients underwent clinical assessment and semiquantitative dipyridamole-201TI imaging and were followed up as outpatients. Patients who underwent coronary revascularization during the follow-up period were excluded from the study because the decision to intervene would have been based at least in part on the test itself. There were 82 cardiac events and 54 noncardiac deaths, and 11 patients were lost to follow-up after a mean follow-up of 15 months. With use of a quantitative index reflecting the amount of jeopardized myocardium, patients could be stratified by dipyridamole imaging into subsets with coronary morbidity and mortality rates ranging from 1% to 89%, (p = 0.0001). When clinical and scintigraphic variables were subjected to backward stepwise logistic regression analysis, the significant predictors of cardiac events were the jeopardized myocardium index by scintigraphy (p < 0.0001), left ventricular hypertrophy on the electrocardiogram (p = 0.0009), and transient dipyridamole-induced left ventricular cavitary dilatation (p = 0.0073). Quantitative dipyridamole-201TI imaging appears to be a powerful predictor of future cardiac events in patients with coronary disease and a low exercise tolerance and is a potentially useful contributor to risk-profile assessment and to the treatment of these patients.

The value of perioperative clinical indexes and dipyridamole thallium scintigraphy for the prediction of myocardial infarction and cardiac death in patients undergoing vascular surgery

BACKGROUND

Dipyridamole thallium scintigraphy has previously been shown to have predictive value for both perioperative and late cardiac events in patients undergoing vascular surgery. However, despite the prognostic utility of this technique, the relative importance of clinical factors and scintigraphic information is not well known. The purpose of this study was to evaluate the value of commonly used clinical risk indexes, composed of historic variables, and dipyridamole thallium scintigraphy for predicting perioperative cardiac event-free survival rates.

METHODS AND RESULTS

Clinical and scintigraphic variables in 360 patients undergoing vascular surgery were analyzed for their predictive utility for perioperative and late (up to 5 years) cardiac events (nonfatal myocardial infarction or cardiac death) by means of chart review and telephone contact. Patients were correctly categorized as being at low, moderate, or high risk for perioperative cardiac events based on two clinical indexes. Thallium redistribution, however, was a more powerful predictor of cardiac events than these indexes. Even in a clinically low-risk patient cohort, the odds ratio for an event increased by 6- to 8-fold (p < 0.05) if thallium redistribution was noted. These indexes also demonstrated prognostic utility for late cardiac event-free survival rates by life-table analysis (p < 0.001). The presence of a fixed thallium defect was associated with an increased risk of late cardiac events (p < 0.01). When stratified by risk index, in those patients at moderate to high risk who had a fixed defect the odds ratio increased by 3.9- to 5.4-fold (p < 0.001). Likewise, the low-risk subgroup had a 3.9- to 8.2-fold increase in the risk of a late cardiac event when a fixed perfusion defect was present.

CONCLUSIONS

Preoperative clinical indexes are predictive of both perioperative and late cardiac events in patients undergoing vascular surgery. However, dipyridamole thallium scintigraphy is more powerful prognostically than these clinical indexes and provides supplemental value to clinical risk stratification.

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.

Perioperative care of the oncology patient

Cancer patients are often at high risk for perioperative complications because of preexisting conditions, the magnitude of surgery, and the use of aggressive multimodality treatment. It is essential to identify risk factors preoperatively, correct any deficits, and monitor organ dysfunction. During the perioperative period prophylaxis and surveillance for cardiopulmonary, hematologic, and septic complications should minimize morbidity and mortality. Finally, nutritional support should be given to malnourished patients undergoing extensive operative procedures.

Extent of jeopardized viable myocardium determined by myocardial perfusion imaging best predicts perioperative cardiac events in patients undergoing noncardiac surgery

OBJECTIVES

This study was undertaken to test the hypothesis that the risk of perioperative cardiac events is not simply determined by the presence of myocardium at risk, but is directly related to the extent of myocardium at risk as reflected in thallium-201 myocardial imaging.

BACKGROUND

The risk of perioperative cardiac events in patients undergoing noncardiac surgery has been related to the presence of transient defects on dipyridamole thallium-201 myocardial imaging, reflecting jeopardized viable myocardium.

METHODS

The study cohort consisted of 231 consecutive patients who underwent noncardiac surgery and had a preoperative dipyridamole thallium-201 imaging study. Patients with vascular reconstruction or bypass constituted the largest surgical subgroup (n = 140). For thallium-201 imaging data, each of three planar projections was divided into three segments (total nine segments) and each segment was interpreted as normal or showing a transient or fixed defect. The ability of clinical and thallium-201 imaging data to predict perioperative cardiac events was compared with stepwise multivariate logistic regression analysis.

RESULTS

Perioperative cardiac events occurred in 19 patients, including 5 with cardiac death, 7 with nonfatal myocardial infarction and 7 with unstable angina. For cardiac death or nonfatal myocardial infarction, the only significant multivariate predictors were the number of myocardial segments with transient thallium-201 defects (p < 0.0005) and a history of diabetes mellitus (p < 0.05). For all cardiac events, the only significant multivariate predictors were the number of myocardial segments with transient defects (p < 0.0001), diabetes mellitus (p < 0.05) and calcium channel blocker use (p < 0.05).

CONCLUSIONS

The probability of important cardiac events in patients undergoing noncardiac surgery is best predicted by the extent of myocardium at risk as reflected on thallium-201 myocardial perfusion imaging. A history of diabetes mellitus also has a significant influence on perioperative risk.

[Value of thallium-dipyridamole myocardial scintigraphy in coronary patients in non cardiac surgery]

Cardiac assessment is of particular importance in patients with documented or suspected coronary artery disease (CAD) as well as in all those patients undergoing vascular surgery. Use of dipyridamole thallium scintigraphy (DTS) in this population could help to detect significant coronary artery narrowing, together with the location and quantification of the areas of myocardium in jeopardy. Such information might lead to changing the surgical procedure, or to starting other treatment, such as coronary angioplasty or bypass graft surgery, thereby diminishing the morbidity and mortality associated with surgery in these high-risk patients. The ability of DTS to predict acute postoperative ischaemic events has been suggested by several studies. Various shortcomings of DTS used as a preoperative screening test have been pointed out in some recent papers. Therefore it is concluded that: 1) DTS should not be used as a routine preoperative test in vascular surgical patients. DTS is not accurate enough when used in patients without any clinical findings suggestive of CAD, 2) DTS may prove more useful in stratifying patients with an intermediate probability of developing cardiac complications. In such patients, the test will not provide a linear "all or nothing" result, but, when taken together with the clinical findings and the nature of the surgical procedure, a complex stratification, 3) Because of progress in the perioperative management of high-risk patients, positive findings on preoperative DTS may not correlate perfectly with perioperative cardiac events, 4) As several factors influence thallium uptake after dipyridamole, DTS does not have a perfect specificity, thus leading to order an excessive number of coronary angiographies. Some patients will be seen as having a false-positive DTS, 5) Preoperative screening DTS leads to cardiac catheterization and hence to revascularisation, independently of symtomatology. Further studies must be undertaken to determine whether this approach will improve short and long term patient survival.

Preoperative and long-term cardiac risk assessment. Predictive value of 23 clinical descriptors, 7 multivariate scoring systems, and quantitative dipyridamole imaging in 360 patients

A total of 360 patients underwent preoperative cardiac risk assessment using 23 clinical parameters, seven multivariate clinical scoring systems, and quantitative dipyridamole-thallium imaging to predict postoperative and long-term myocardial infarction and cardiac death after noncardiac surgery. There were 30 postoperative and an additional 13 cumulative long-term cardiac events after an average follow-up of 15 months. Clinical descriptors were not useful in predicting the outcome of individual patients. The postoperative and long-term cardiac event rates were 1% and 3.5%, respectively, in patients with normal scans or fixed perfusion defects, and 17.5% and 22% in patients with reversible defects. Using quantitative indices reflecting the amount of jeopardized myocardium, patients could be stratified by dipyridamole imaging into multiple scintigraphic subsets, with corresponding postoperative and 1-year coronary morbidity and mortality rates ranging from 0.5% to 100% (p = 0.0001). Thus, postoperative and long-term cardiac events cannot be predicted clinically, whereas quantitative dipyridamole imaging accurately identifies high-risk patients who require preoperative coronary angiography.

A comparison of tablets with oral suspension formulation of dipyridamole in thallium myocardial imaging

Dipyridamole stress thallium imaging has been widely employed to diagnose and assess the extent of coronary heart disease in patients who cannot exercise. When oral dipyridamole administration was used, a wide range of results for sensitivity, specificity, hemodynamic response and side effect profile has been reported. The authors hypothesized that the formulation used for oral administration of dipyridamole plays a major factor in this variability, and that the pulverized form of dipyridamole will achieve faster and more consistent response than the standard tablet form. The authors studied 13 consecutive patients who underwent thallium scintigraphy. Eight patients received dipyridamole pulverized and dissolved in a glycol/aqueous base diluent (group A), and five patients received the standard form of dipyridamole (group B). In group A, mean peak systolic blood pressure decreased from 142 +/- 31 (mean +/- standard deviation) to 109 +/- 30 (P = .05), and mean diastolic blood pressure decreased from 76 +/- 14 to 51 +/- 5. The mean heart rate changed from 78 +/- 26 to 80 +/- 10. In group B, baseline systolic blood pressure was 165 +/- 12 and decreased to 156 +/- 7 at 45 minutes and to 155 +/- 14 at 90 minutes. Heart rate increased from baseline of 69 +/- 9 to 75 +/- 8 at 45 minutes and to 76 +/- 11 at 90 minutes. At 45 minutes, the systolic blood pressure of the 8 group A patients dropped by 33 +/- 19 mm Hg, whereas group B's changed by 9 +/- 6 mm Hg (P less than .005).(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic implications of a negative dipyridamole-thallium scan: results in 360 patients

PATIENTS AND METHODS

A total of 360 patients with either normal perfusion (314) or fixed defects (46) on dipyridamole-thallium scans were followed over an average period of 16 months. Of the 360 patients, 194 subsequently underwent major noncardiac surgery.

RESULTS

There were a total of eight cardiac events including two postoperative complications (one fatal and one nonfatal myocardial infarction) and six cardiac events during long-term follow-up (one sudden death and five nonfatal infarctions). During the follow-up period, three patients underwent coronary artery bypass surgery. The low cardiac event rate could not be explained by a low pretest likelihood of coronary artery disease: 77% of the 360 patients had either typical angina pectoris, a previous myocardial infarction, or peripheral vascular disease, which is associated with a high prevalence of coronary artery disease.

CONCLUSIONS

In patients with a high pretest likelihood of coronary artery disease, the absence of thallium redistribution on a dipyridamole-thallium scan denotes a very low (1%) cardiac risk for major noncardiac surgery as well as low long-term cardiac mortality (0.3%) and morbidity (1.4%) rates. The coronary death rate is comparable to that of patients with minimal (less than 50%) coronary stenoses.

The role of a defined protocol for cardiac risk assessment in decreasing perioperative myocardial infarction in vascular surgery

Major elective peripheral vascular surgery has historically carried a significant risk of perioperative myocardial infarction; this risk has been quantified further by its association with proved reduction in cardiac reserve/presence of coronary artery disease by stress testing or invasive monitoring. Recognition of this risk logically should lead to protocols that delineate coronary artery disease/cardiac reserve before surgery and correct for observed abnormalities during surgery. This study sought to show that a coherent algorithm of preoperative cardiac assessment combined with aggressive perioperative management could indeed reduce perioperative myocardial infarction rates. Six hundred thirty consecutive elective vascular operations were performed by the author during 6 years. All patients were entered into a prospective protocol for preoperative cardiac risk assessment, which then determined the choice of operation, type of anesthesia, and level of hemodynamic monitoring. Sixty-eight percent of the patients demonstrated clinical coronary artery disease, 15% had previously undergone coronary catheterization or surgery, and 9% had ejection fractions less than 35%. All patients underwent baseline detailed cardiac histories, radionuclide cardioangiography, and electrocardiograms. Patients with significant historic coronary artery disease or ejection fraction less than 50% underwent stress thallium testing; patients with positive fixed or redistribution defects then underwent catheterization, constituting 7% of the series. Risk stratification by age and cardiac assessment then dictated the perioperative care. The overall perioperative myocardial infarction rate was 0.7% (5/628), ranging from 0% for 156 aortic operations and 114 carotid endarterectomies to 0.6% for 159 femoropopliteal and 3.3% for 90 femorotibial revascularizations.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic value of dipyridamole thallium-201 scintigraphy in patients with stable chest pain

The usefulness of dipyridamole testing with planar thallium-201 scintigraphy for assessing risk of subsequent cardiac events was evaluated in 373 patients with stable chest pain. Follow-up information was complete in 362 patients (mean age 64 +/- 9 years). During an average follow-up period of 18 months, cardiac events occurred in 59 patients--unstable angina in 27, nonfatal acute myocardial infarction in 11, and death from cardiac causes in 21. A history of previous myocardial infarction, congestive heart failure, or coronary bypass surgery before the study, or the presence of an abnormal scan or one with a fixed perfusion defect was associated with a significantly increased frequency of subsequent cardiac events (p less than 0.05). However, the presence of a reversible perfusion defect was not associated with increased risk (p = 0.1872). Stepwise logistic regression showed that a history of coronary artery bypass surgery before the study and the presence of a fixed perfusion defect were the only variables with independent predictive value for occurrence of a subsequent cardiac event (p less than 0.05). Survival analysis revealed a significantly increased cardiac event rate in patients with abnormal scans compared with those with normal scans over a 30-month follow-up period (p less than 0.01). We conclude that dipyridamole testing with thallium-201 scintigraphy can provide prognostic information concerning risk of future cardiac events in patients with stable chest pain. The presence of a fixed perfusion defect in particular identifies patients at increased risk.

Use of stress thallium imaging to stratify cardiac risk in patients undergoing vascular surgery

Reduction of the cardiac morbidity associated with major vascular procedures requires identification of high risk patients prior to operation. This retrospective study reviews the records of 126 consecutive patients who underwent 141 major vascular procedures to determine the accuracy of preoperative clinical, laboratory (ECG), and cardiac function testing (stress thallium-201 scintigraphy, left ventricular ejection fraction scan) in predicting perioperative cardiac complications. An abnormality on oral dipyridamole or treadmill thallium imaging was demonstrated prior to 71 (61%) of 116 procedures and included 20 fixed and 51 reperfusion (reversible) defects. No patient died within 30 days of operation, but 11 minor (ventricular arrhythmia) and 15 major (myocardial infarction, ischemic congestive heart failure) cardiac complications occurred. A reperfusion defect on stress thallium imaging accurately (94% sensitivity, 56% specificity, 98% negative predictive value) identified high-risk patients while accepted clinical rating systems (Goldman, Cooperman, Eagle) and preoperative level of left ventricular ejection fraction were less predictive of adverse cardiac events. Patients without myocardium at risk by coronary angiography, but a reperfusion defect on stress thallium imaging were found to be at high risk for a cardiac complication. The study data support the use of stress thallium imaging to stratify cardiac risk prior to major arterial surgery.

Multivariate clinical models and quantitative dipyridamole-thallium imaging to predict cardiac morbidity and death after vascular reconstruction

Patients with peripheral vascular disease have a high prevalence of coronary artery disease and are at increased risk for cardiac morbidity and death after vascular reconstruction. The present study was undertaken to assess the value of 18 clinical parameters, of 7 clinical scoring systems, and of quantitative dipyridamole-thallium imaging for predicting the occurrence of postoperative myocardial infarction or cardiac death. Vascular surgery was performed in 125 patients. Thirteen postoperative cardiac events occurred, including 10 cardiac deaths and 3 nonfatal infarctions. Clinical parameters were not useful in predicting postoperative outcome. All 63 patients with normal scan results or fixed perfusion defects underwent surgery uneventfully, whereas 21% (13/62) of patients with reversible defects had a postoperative cardiac complication. By use of quantitative scintigraphic indexes we found that patients with reversible defects could be stratified into intermediate and high-risk subgroups with postoperative event rates of 5% (2/47) and 85% (11/13), respectively, despite intensive postoperative monitoring and antianginal medication. Thus in patients unable to complete a standard exercise stress test, postoperative outcome cannot be predicted clinically, whereas dipyridamole-thallium imaging successfully identified all patients who had a postoperative cardiac event. By use of quantification we found that patients with reversible defects can be stratified into an intermediate risk subgroup that can undergo surgery with minimal complication rate and a high-risk subgroup that requires coronary angiography.

Impact of aging on preoperative evaluation

Approximately 40% of physician office time and 33% of hospital time are devoted to patients 65 years of age or older. Over half of the older population requires some surgical intervention. Because of decreased physiologic reserve and increased number of underlying medical disorders, the older patient is at increased risk for intraoperative and postsurgical complications. Since cardiovascular, pulmonary, and renal complications are frequent in the elderly patient, the preoperative evaluation should emphasize these organ systems. Risk factors should be assessed initially by a focused history and physical examination and by simple tests. Additional diagnostic testing should be reserved for the patient who is not clearly at low or high risk. For optimal preoperative evaluation of the elderly patient, the physician should identify systemic disease, determine if the patient is receiving appropriate therapy, delineate the operative risks, and make recommendations that can potentially reduce the operative risks and postoperative complications.

Upper abdominal cancer surgery in the very elderly

From January 1981 to December 1987, 59 major upper abdominal operations were performed on 57 patients aged 80 to 90 years at Memorial Sloan-Kettering Cancer Center. Procedures for primary adenocarcinoma of the stomach, distal esophagus, pancreas, or hepatobiliary system were performed with curative intent or for palliation in 34 of 59 patients (58%) and bypass with limited or no resection in 13 of 59 patients (22%) patients. Emergency operations were performed in six (10%) patients for gastric bleeding, perforation, or outlet obstruction. Six (10%) patients underwent laparotomy for benign biliary obstruction (1), splenectomy for secondary thrombocytopenia (2), or gastrectomy for sarcoma (2) or lymphoma (1). Hospital mortality was 15% overall and 9% for major resections, 15% for bypass, and 67% for emergency procedures. Major complications occurred in 10 (20%) elective procedures. Mortality was associated with respiratory or cardiac failure while complications most commonly included arrhythmias and wound infection. Mean postoperative hospitalization was 18 days overall and 45 patients (76%) were discharged home. Median survival following major resection was 17.5 months but less than 2 months after bypass procedures. A protocol of pre-operative evaluation, intra-operative hemodynamic monitoring and postoperative intensive care has been formalized for use in elderly or poor-risk patients.

Selective evaluation and management of coronary artery disease in patients undergoing repair of abdominal aortic aneurysms. A 16-year experience

Reduction of cardiac mortality associated with abdominal aortic aneurysm (AAA) repair remains an important goal. Five hundred consecutive urgent or elective operations for infrarenal nonruptured AAA were reviewed. Patients were divided into three groups based on preoperative cardiac status: group I (n = 260, 52%), no clinical or electrocardiographic (ECG) evidence of coronary artery disease (CAD); group II (n = 212, 42.2%), clinical or ECG evidence of CAD considered stable after further evaluation with studies such as dipyridamole-thallium scanning, echocardiography, or coronary arteriography; group III (n = 28, 5.6%), clinical or ECG evidence of CAD considered unstable after further evaluation. Group I had no further cardiac evaluation and groups I and II underwent AAA repair without invasive treatment of CAD. Group III underwent repair of cardiac disease before (n = 21) or coincident with (n = 7) AAA repair. In all instances, perioperative fluid volume management was based on left ventricular performance curves constructed before operation. The 30-day operative mortality rate for AAA repair in all 500 patients was 1.6% (n = 8). There was one (0.4%) cardiac-related operative death in group I, which was significantly less than the five (2.4%) in group II (p less than 0.02). Total mortality for the two groups were also significantly different, with one group I death (0.4%) and seven group II deaths (3.3%), (p less than 0.02). These data support the conclusions that (1) the leading cause of perioperative mortality in AAA repair is myocardial infarction, (2) correction of severe or unstable CAD before or coincident with AAA repair is effective in preventing operative mortality, (3) patients with known CAD should be investigated more thoroughly to identify those likely to develop perioperative myocardial ischemia so that their CAD can be corrected before AAA repair, and (4) patients with no clinical or ECG evidence of CAD rarely die of perioperative myocardial infarction, and thus selective evaluation of CAD based on clinical grounds in AAA patients is justified.