KEY POINTS

1. Advances in our understanding of the biology of acquired cardiovascular disease and advances in interventional cardiology and radiology have resulted in patients presenting for surgery who are older and who suffer from more comorbid conditions.
2. Age, per se, is now recognized as an independent risk factor for cardiovascular disease.
3. Atherosclerosis, including atherosclerotic coronary artery disease, results from a vascular response to injury and ultimately leads to plaque formation.
4. Myocardial ischemia can be manifested as angina and acute coronary syndromes and as stunning, hibernation, and preconditioning.
5. Plaque instability and acute thrombus formation are seminal mechanisms underlying the development of acute coronary syndromes. Management of these patients is contingent on an understanding of the mechanisms underlying thrombus formation and the successful interrogation thereof.
6. Hemodynamic manipulation of the determinants of myocardial oxygen supply and demand is a critical aspect of managing patients with myocardial ischemia and is increasingly important with increasing severity of coronary stenosis.

---

1996

7. Stunning describes the phenomena whereby transient myocardial ischemia followed by restoration of normal coronary flow induces postischemic myocardial dysfunction in the absence of myocardial necrosis.
8. Hibernation describes myocardial dysfunction in the setting of impaired blood flow and a parallel decrease in myocardial metabolism.
9. Preconditioning is characterized by the ability of brief ischemia to attenuate the consequences of a subsequent greater ischemic insult.
10. α-Blockers exert a salutatory effect on the determinants of myocardial oxygen supply and demand. These beneficial effects extend beyond that of a reduction in heart rate and an increase in diastolic interval.
11. Nitrates are used to treat acute myocardial ischemia. However, recent studies investigating the mechanisms underlying the effects of nitrates and long-term outcome data indicate that the acute effects of nitrates do not necessarily translate into long-term beneficial effects.
12. Successful management of any cardiovascular condition is contingent on an understanding of the underlying pathophysiology in that specific condition.
13. Aortic stenosis is a common indication for cardiac surgery. Hemodynamic stability is critically dependent on maintenance of sinus rhythm and adequate afterload and thus coronary perfusion pressure.
14. Hypertrophic cardiomyopathy is associated with outflow obstruction in only a minority of patients. In contrast, all such patients have diastolic dysfunction. The hemodynamic goals are determined by the need to decrease potential ventricular outflow obstruction by decreasing inotropy and the heart rate and maintaining euvolemia and afterload.
15. The hemodynamic goals in aortic regurgitation are to maintain adequate forward flow by decreasing afterload, avoiding bradycardia, and if necessary, increasing inotropy.
16. Successful management of patients with mitral stenosis is contingent on an understanding of the relationship between mitral flow, mitral valve area, and the transvalvular pressure gradient (see Fig. 50-23 ).
17. Patients with mitral regurgitation can be difficult to manage perioperatively in that myocardial function is difficult to determine accurately preoperatively. Mitral valve repair or replacement may unmask myocardial dysfunction.
18. Patients with cardiac tamponade physiology invoke endogenous compensatory mechanisms to maintain cardiac output. Successful management of these patients recognizes this principle, as well as the need for volume resuscitation and adequate preload to maintain cardiac output.
19. Many anesthetic regimens are used for patients undergoing cardiac surgery. However, the most frequently used regimen is that of a balanced anesthetic technique incorporating major narcotics, tranquilizers, and volatile anesthetics.
20. Anesthetic regimens can be modified with a view to expediting extubation after surgery (fast-track anesthesia).
21. Although many revascularization procedures are now conducted off cardiopulmonary bypass, all valve procedures and many revascularization procedures still require cardiopulmonary bypass.
22. Cardiopulmonary bypass activates several inflammatory cascades, including the complement pathway, the cytokine system, the coagulation and antifibrinolytic systems, cellular immune mechanisms, inducible nitric oxide synthase, and oxidant stress pathways.
23. Myocardial protection is an essential feature of cardiopulmonary bypass with aortic cross-clamping. The principles underlying the mechanisms used to ensure myocardial protection are dependent on minimizing cellular oxygen requirements during the period of anoxic arrest by stopping the heart and maintaining myocardial hypothermia.
24. Pressure, flow, and flow patterns during cardiopulmonary bypass are unphysiologic. Monitoring during cardiopulmonary bypass is ultimately determined by the need to assess the adequacy of tissue oxygenation.
25. Bleeding after cardiopulmonary bypass is common. It has a multifactorial etiology, including activation of hemostatic factors, hemodilution, and activation of platelets.
26. Post-revascularization myocardial ischemia is not uncommon, and its significance should be assessed in the context of its magnitude and distribution, the surgical circumstances, and whether concurrent myocardial dysfunction and dysrhythmias are present.
27. Although myocardial dysfunction after anoxic arrest may involve the right or left ventricles and may involve either diastolic or systolic dysfunction, severe dysfunction should be relatively uncommon in the setting of adequate myocardial protection.
28. If myocardial dysfunction develops, it is initially treated pharmacologically (inotropes, lusitropic agents, afterload reduction). If necessary, mechanical support is used.
29. Mechanical circulatory support systems can be used acutely in the setting of myocardial dysfunction, chronically as a bridge to transplantation, or in the future as destination therapy.
30. Atrial fibrillation is the most common postoperative cardiac dysrhythmia and usually develops 1 to 3 days postoperatively.
31. Neurologic injury is common after cardiac surgery and can be manifested by focal deficits, the development of neurocognitive deficits, or both.
32. Many of the techniques developed in cardiac surgery are motivated by the desire to decrease neurologic complications. Such techniques include the development of off-pump procedures. Thus far, the goal of decreasing neurologic complications has not necessarily been realized.