Current practice and recommendation for presurgical cardiac evaluation in patients undergoing noncardiac surgeries

Abstract

The increasing number of patients with coronary artery disease (CAD) undergoing major noncardiac surgery justifies guidelines concerning preoperative cardiac evaluation. This is compounded by increasing chances for a volatile perioperative period if the underlying cardiac problems are left uncorrected prior to major noncardiac surgeries. Preoperative cardiac evaluation requires the clinician to assess the patient's probability to have CAD, severity and stability of CAD, placing these in perspective regarding the likelihood of a perioperative cardiac complication based on the planned surgical procedure. Coronary events like new onset ischemia, infarction, or revascularization, induce a high-risk period of 6 weeks, and an intermediate-risk period of 3 months before performing noncardiac surgery. This delay is unwarranted in cases where surgery is the mainstay of treatment. The objective of this review is to offer a comprehensive algorithm in the preoperative assessment of patients undergoing noncardiac surgery and highlight the importance of myocardial perfusion imaging in risk stratifying these patients.

Keywords: Cardiac risk stratification; coronary artery disease; heart; noncardiac surgeries; stress myocardial perfusion imaging; surgery.

Figure 1

Depicts the myocardial ischemic cascade and stepwise changes, which occur at molecular and tissue level. Acute coronary syndrome is typically initiated with acute plaque rupture and subsequent intracoronary thrombus development. These changes happen when epicardial coronary flow is interrupted and leads to an imbalance between myocardial oxygen supply and demand, reduced myocardial perfusion, regional ventricular dysfunction, and ST-segment changes and finally angina pectoris, which when severe, results in myocardial ischemia. If this condition is prolonged, myocardial necrosis occurs. Therefore diagnostic techniques that can identify earlier components of this pathway, such as myocardial perfusion imaging have the potential for allowing earlier identification. The characteristic electrocardiogram changes in repolarization are noted 20-30 s after a coronary occlusion. Reduction in myocardial blood flow is the first detectable event in the ischemic cascade, while clinical anginal symptoms are the last in the temporal sequence of the ischemic cascade. Myocardial troponin usually rises by 8-24 h after surgery

Figure 2

Normal stress myocardial perfusion scan in a 48-year-old lady planned for total hip replacement surgery – low risk for cardiac events

Figure 3

Pharmacological stress myocardial perfusion imaging in a 56-year-old male with peripheral vascular disease showing a small infarct involving apex with peri-infarct reversible ischemia. There is associated reversible ischemia in parts of anterior and inferior segments of left ventricular (left anterior descending and right coronary artery territory) -intermediate to high-risk for peri-and post-operative cardiac events if untreated prior to surgery

Figure 4

Stress and rest myocardial perfusion imaging images of a 32-year-old lady displayed in 2 different color scales (a and b). Patient presented with acute coronary syndrome. Images show reversible ischemia in anterior and septal segments of left ventricular myocardium (left anterior descending territory ischemia) -intermediate to high-risk for peri-and post-operative cardiac events if left untreated prior to surgery