Cardiac risk for vascular surgery

The Preoperative Evaluation of the Patient With Cardiac Risk Factors for Noncardiac Surgery: Which Patients Need Further Cardiac Risk Stratification Tests?

Cardiac risk stratification tests should be pursued only in the subgroup of patients who have a moderate to high incidence of significant coronary artery disease and only in those who will gain long-term benefit from coronary revascularization if they are found to have significant coronary artery disease. Furthermore, car diac risk stratification tests should be pursued only if the perioperative mortality and morbidity from com bined coronary revascularization followed by noncar diac surgery is not significantly higher than proceeding straight to noncardiac surgery alone. Indentification of the subgroup of patients who will need cardiac strati fication tests should be based on integration of the patient's cardiac risk factors and functional capacity with the risk and stress of the particular surgery.

Role of tumor necrosis factor-α in myocardial dysfunction and apoptosis during hindlimb ischemia and reperfusion

OBJECTIVE

Peripheral vascular surgery involving limb ischemia/reperfusion is associated with tumor necrosis factor-alpha production and an increased risk of cardiac complications. The objective of this study was to investigate the role of tumor necrosis factor-alpha in myocardial apoptosis and dysfunction following hindlimb ischemia/reperfusion.

DESIGN

Randomized perspective animal study.

SETTING

Research laboratory.

SUBJECTS

Adults male tumor necrosis factor-alpha(-/-) and littermate wild-type mice.

INTERVENTIONS

Bilateral hindlimb ischemia/reperfusion was induced in wild-type and tumor necrosis factor-alpha(-/-) mice using tourniquet occlusion. After 2 hrs of hindlimb ischemia, the tourniquets were released, allowing reperfusion for 0.5-24 hrs.

MEASUREMENTS AND MAIN RESULTS

In wild-type mice, hindlimb ischemia/reperfusion resulted in myocardial depression early during the reperfusion period (p < .05). These effects were temporally correlated with enhanced levels of myocardial and plasma tumor necrosis factor-alpha. All variables were restored to baseline levels by 24 hrs of reperfusion. Myocardial apoptosis, assessed by cell death enzyme-linked immunosorbent assay, terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick-end labeling staining, and caspase-3 activity, was also significantly higher at 6 hrs of reperfusion (p < .05) but returned to baseline levels by 24 hrs. Interestingly, cardiac dysfunction and myocardial apoptosis were abolished in tumor necrosis factor-alpha mice subjected to the same degree of hindlimb ischemia/reperfusion as the wild-type mice. Treatment of etanercept restored cardiac function in wild-type mice.

CONCLUSIONS

Tumor necrosis factor-alpha contributes significantly to myocardial dysfunction and apoptosis in hindlimb ischemia/reperfusion. Although a causal link between myocardial apoptosis and cardiac dysfunction is not established, our study does suggest that tumor necrosis factor-alpha may be a potential therapeutic target for cardiac injury in clinical situations involving prolonged remote ischemia/reperfusion.

Preoperative screening

In screening the preoperative patient, several sources of risk, each with potentially modifiable components, must be considered. These include risks related to the proposed procedure, anesthetic, and medical illnesses present in the patient. To screen effectively, one must look for potential factors in each area that may affect perioperative morbidity and mortality. Once risk areas are identified, it is helpful to quantify them further through a focused testing approach, especially when the anticipated surgical or anesthetic risks are high. Data obtained through this process should guide the optimization of the patient's medical status to modify risks when possible. Sharing information obtained during the preoperative assessment with both anesthesiologists and surgeons helps to refine plans for management and may better ensure patient safety in the perioperative period.

Increased incidence of periprocedural complications among patients with peripheral vascular disease undergoing myocardial revascularization in the bypass angioplasty revascularization investigation

BACKGROUND

Risks of coronary artery bypass graft surgery (CABG) or percutaneous transluminal coronary angioplasty (PTCA) may be different in the presence of peripheral vascular disease (PVD).

METHODS AND RESULTS

We analyzed outcomes of 550 patients with PVD enrolled in the Bypass Angioplasty Revascularization Investigation randomized trial and registry. Compared with 1770 patients without PVD, those with PVD were older and had a greater prevalence of medical comorbid conditions. No significant differences in coronary anatomy or PTCA success rates were found. The risk of any major complication (death, myocardial infarction, stroke, coma, or emergency revascularization) after PTCA was significantly higher among patients with PVD (11.7% versus 7.8%, P=0.027). In multivariate analysis, this represented a 50% increase in the odds of having any major complication (multivariate odds ratio, 1.5; P=0. 032). Among patients undergoing CABG, the risk of major complications was found to be markedly higher for patients with PVD (12%) than those without (6.1%, P=0.003) even after controlling for baseline differences (multivariate odds ratio, 1.8; P=0.018). Major differences between the PTCA and CABG groups were related primarily to a higher risk of neurological complications in PVD patients who had CABG (multivariate odds ratio, 2.8; P<0.001).

CONCLUSIONS

We conclude that patients with PVD are at high risk for periprocedural complications after myocardial revascularization, in particular neurological events.

The role of myocardial revascularization preceding noncardiac surgery

Of about 6.7 million Americans who have coronary artery disease, approximately 700,000 undergo various noncardiac operations annually in the United States. Perioperative cardiac complications remain the leading cause of morbidity and mortality not related to the primary operative procedure; the mechanisms of perioperative ischemia and infarction are unclear. Currently, clinicians, using a combination of clinical and laboratory findings, can estimate the risk of noncardiac surgical procedures with a high degree of precision, but much less is known about the preferred approach to patient management after noninvasive risk stratification. Coronary angiography and revascularization are frequently recommended for those determined by functional tests to be at moderate and high risk, but the risks of revascularization are often substantially higher among these patients. No randomized, controlled trials exist to guide patient management. Quantitative decision analysis based on published nonrandomized data suggests that coronary angiography with selective myocardial revascularization should be performed to reduce the risk of noncardiac surgery only if the risk of noncardiac surgery is greater than 5% and the risk of coronary angiography with selective revascularization is less than 3%. On the other hand, if independent indications exist for myocardial revascularization, it should generally be performed before the noncardiac operation.

[Role of noninvasive examinations in the management of ischemic cardiopathy. V. Noninvasive examinations in the management of patients with chronic ischemic cardiopathy]

In the last few years the has been an enormous development in noninvasive testing in the field of clinical cardiology. In fact, excellent monographs on each one of these techniques have been published elsewhere, but fewer publications exist that treat the topic of their indications and use in an integrated way, except for in the most common clinical situations. In this paper, the treatment of patients who present chest pain, stable and unstable angina is discussed, including the study of postinfarction patients. Furthermore, the role of noninvasive tests in the detection of coronary heart disease in women and in patients with left bundle branch block is thoroughly analyzed; as well as their usefulness after surgical or percutaneous coronary revascularization and in patients with peripheral vascular disease.