114 PREOPERATIVE EVALUATION OF CARDIOVASCULAR DISEASE
Harrison’s Manual of Medicine
PREOPERATIVE EVALUATION OF CARDIOVASCULAR DISEASE
Specific Cardiac Conditions
Goal is to determine if cardiovascular disease is present, assess its severity and stability, and intervene if necessary to minimize surgical risk. Greatest cardiovascular risk occurs with aortic (or other major vascular), intrathoracic, or intraperitoneal procedures or emergent operations in patients of advanced age (Table 114-1).
Table 114-1 Cardiac Risk of Noncardiac Procedures
HISTORY Assess for history of MI, angina, CHF, valvular disease, hypertension, symptomatic arrhythmia. Note pertinent concomitant illnesses (e.g., cerebrovascular disease, diabetes mellitus, pulmonary or renal disease, anemia). Review pt’s functional capacity in daily life (e.g., ability to perform housework, climb stairs, exercise).
PHYSICAL EXAMINATION Evaluate for uncontrolled hypertension, signs of CHF (jugular venous distention, rales, S3), previously unknown heart murmurs, carotid bruits. Inspect for pallor, cyanosis, poor nutritional state.
LABORATORY Examine ECG for evidence of previous MI (Q waves) or arrhythmias. Inspect CXR for signs of CHF (e.g., cardiomegaly, vascular redistribution, Kerley B lines). Additional testing is dictated by specific underlying cardiovascular disease and nature of the planned operation. See Fig. 114-1 for clinical predictors of increased perioperative risk of MI, CHF, or death and approaches to preoperative evaluation.
FIGURE 114-1. Approach to preoperative cardiac evaluation. *Significant arrhythmias include: (1) High-grade AV block, (2) symptomatic ventricular arrhythmias, and (3) supraventricular arrhythmias with uncontrolled ventricular rate. †Exercise testing is preferred (treadmill, bicycle, arm ergometry). Perform with echo or nuclear scintigraphy if baseline ST-T waves preclude ECG interpretation. If unable to exercise, consider pharmacologic (e.g., dobutamine or adenosine) test with echo or nuclear imaging, or ambulatory ECG monitoring, if baseline ST-T waves normal. (Modified from KA Eagle et al: Circulation 93:1278, 1996, with permission.)
SPECIFIC CARDIAC CONDITIONS
CORONARY ARTERY DISEASE Consider postponing purely elective operations for 6 months following an MI. Pts with stable CAD can be evaluated per algorithm in Fig. 114-1. Surgical risk is generally acceptable in pts with class I–II symptoms (e.g., able to climb one flight carrying grocery bags) and in those with low-risk results from noninvasive testing (see Table 122-1 for recommended forms of stress testing). For those with high-risk results (Chap. 122) or very limited functional capacity, consider coronary angiography. Perioperative beta-blocker therapy reduces incidence of coronary events and should be included in medical regimen if no contraindications (Chap. 122).
HEART FAILURE This is a major predictor of perioperative risk. Regimen of ACE inhibitor and diuretics should be optimized preoperatively to minimize risk of either pulmonary congestion or intravascular volume depletion postoperatively.
ARRHYTHMIAS These are often markers for underlying CHF, CAD, drug toxicities (e.g., digitalis), or metabolic abnormalities (e.g., hypokalemia, hypomagnesemia), which should be identified and corrected. Indications for antiarrhythmic therapy or pacemakers are same as in nonsurgical situations (Chap. 115). Notably, asymptomatic ventricular premature beats generally do not require suppressive therapy preoperatively.
VALVULAR DISEASES Those portending greatest surgical risk are advanced aortic or mitral stenosis (Chap. 118), which should be repaired, if severe or symptomatic, prior to elective surgery. Ensure adequate ventricular rate control in mitral stenosis with atrial fibrillation (using beta blocker, digoxin, verapamil, or diltiazem). Endocarditis prophylaxis is indicated for operations associated with transient bacteremias (Chap. 80).
HYPERTENSION This carries a risk of labile bp or hypertensive episodes perioperatively. Control elevated pressure preoperatively (Chap. 124), especially using beta blocker if possible, which should be continued perioperatively. If pheochromocytoma is a possibility, surgery should be delayed for evaluation because of high anesthetic risk.