- The elective patient for cardiac anesthesia and surgery free of other disease processes is increasingly a rara avis. Prior to advances in percutaneous interventions, the routine cardiac surgery patient was an otherwise healthy middle-aged man in need of a one to two vessel coronary artery bypass—How times have changed. Today's cardiac surgery patient is likely to be quite elderly with multiple medical problems presenting for combined revascularization and valvular replacement surgery. Moreover, many patients will have had over the course of their lives other cardiac procedures including previous operations and/or percutaneous interventions. Further complicating matters, many of these patients suffer from systolic and diastolic dysfunction, some with remarkably low ejection fractions to less than 20%. Consequently, the "healthy" patient for heart surgery is an oxymoron.
In past decades, patients presented for cardiac surgery in need of one to two vessel bypass grafts. Usually, their chief complaint was angina and they had no or minimal myocardial damage. Patients with ejection fractions (EFs) of greater than 60% were the rule and not the exception.
Such patients tended to tolerate the peri-induction period well and were readily separated from cardiopulmonary bypass (CPB) with little need for pharmacological or mechanical support. Ventricular function tended to be preserved periopertively assuming acceptable myocardial preservation and surgical techniques.
Today's cardiac surgical patient is far more challenging. Patients are older with varying degrees of systolic and diastolic dysfunction frequently presenting in congestive heart failure.
Congestive heart failure affects more than 5 million Americans with coronary artery disease as a primary etiology.1 Cardiac surgical outcomes are worse in patients with previous episodes of congestive heart failure, chronic obstructive pulmonary disease, increased age, and peripheral vascular disease (Figure 5–1).
In a retrospective analysis of 525 patients with ejection fractions less than 25% long-term outcomes were identified in these Kaplan-Meier survival curves. Increasing age (A), presence of peripheral vascular disease (B), emergent nature of surgery (C), presence of chronic obstructive pulmonary disease (D), and previous episodes of pulmonary congestion (E) all predict a poorer long-term outcome following coronary artery bypass surgery. (With permission from: DeRose J, Tompoulis I, Balaram S, et al. Preoperative prediction of long-term survival after coronary artery bypass grafting in patients with low left ventricular ejection fraction. J Thorac Cardiovasc Surg. 2005;129:314-321.)
However, preserved right ventricular function in the setting of a severely compromised left ventricle (EF < 25%) may improve perioperative outcomes2 (Figure 5–2). Impaired LV diastolic function produces an increase in left ventricular end-diastolic pressure (LVEDP) that is transmitted to the pulmonary circulation. A patient whose right ventricle functions well, tolerates any perioperative worsening in LV diastolic dysfunction and has a potentially better surgical outcome. Consequently, if the right heart is working the patient with severe LV dysfunction will tolerate better surgical revascularization ...