Perioperative and Long-Term Morbidity

To appreciate the importance of preoperative evaluation, the incidence of MI and death in patients undergoing peripheral vascular surgery must be considered ( Table 52-1 ) (see Chapter 24 ). Nonfatal and fatal MIs are the most important and specific outcomes that determine perioperative cardiac morbidity. When multiple studies are pooled, the overall prevalence of perioperative MI and death is 4.9% and 2.3%, respectively. When outcomes are assessed over the long-term postoperative period (3 to 4 years), the prevalence of MI and death is 8.9% and 9.1%, respectively.

The challenge for clinicians is to accurately assess risk for cardiac morbidity while maintaining a cost-effective and clinically relevant strategy. After risk assessment, there is the additional challenge of modifying perioperative management to reduce risk by adjusting or adding cardiac medication (e.g., β-blocker), direct coronary intervention (e.g., percutaneous transluminal coronary angioplasty [PTCA] or coronary artery bypass grafting [CABG]), modifying or intensifying perioperative management (e.g., invasive hemodynamic monitoring), or changing preoperative plans (e.g., performing endovascular aortic repair rather than open aortic repair). Coordination is essential among surgeons, anesthesiologists, and cardiologists, each of whom may have different criteria for risk modification. Although some investigations have enthusiastically promoted the use of preoperative cardiac testing, perioperative clinicians do not always agree on which patients should be tested and how. The cost of these tests is a limiting feature; Mangano^[26] estimated that annual health care costs would rise by $100 million if preoperative dipyridamole thallium imaging (DTI) were used for only one half of all vascular surgery patients. Even when selective criteria are used to determine which vascular patients need preoperative testing, one estimate is that $2936 per patient would be the average cost of testing, with subsequent coronary intervention by PTCA or CABG for patients with correctable CAD.^[28] Extensive cardiac evaluation before vascular operations can result in morbidity, delays, and patient refusal to undergo vascular surgery.^[29]

Because PTCA and CABG have inherent risks, additional controversies arise. Although retrospective studies abound, there are no level I data to guide preoperative decision-making leading to coronary intervention. In interpreting the few published outcome studies, the physician must recognize that overall mortality must include the mortality related to the coronary intervention and the mortality related to the vascular surgery procedure itself.

2054

An excellent review of the literature and guidelines for perioperative cardiovascular evaluation for noncardiac surgery^[31] have been updated by the American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Practice Guidelines.^[32] These guidelines were produced by a task force that included cardiologists, internists, anesthesiologists, and surgeons. Preoperative testing to assess coronary risk, management of specific preoperative conditions, supplemental preoperative evaluation, perioperative therapy for CAD, anesthetic considerations and intraoperative management, perioperative surveillance, and postoperative management are all discussed. An explicit algorithm for preoperative cardiac assessment is outlined in these guidelines ( Fig. 52-3A and Fig. 52-3B ). One of the guiding principles of this document is that "preoperative intervention is rarely necessary simply to lower the risk of surgery unless such intervention is indicated irrespective of the preoperative context." Another excellent review addresses this topic, with specific emphasis on the vascular surgical patient.^[33]