Chapter 45: Valvular and Ischemic Heart Disease

INTRODUCTION

Recently, there have been exciting developments involving new technologies for the surgical treatment of valvular heart disease associated with coronary artery disease (CAD). Interventional therapies for coronary artery obstruction have been extended to multivessel disease with hybrid procedures (targeted percutaneous interventions staged with limited access surgical coronary bypass surgery) and continues to change the number and nature of patients referred for surgery.¹ Similarly, the surgical treatment of structural valvular heart disease has continued to expand with advances in techniques for repair, as well as total valve replacement and valve-sparing repair options for both aortic and mitral valve abnormalities.² Most recently, bioprosthetic valve manufacturing advances in regard to calcium mitigation, tissue processing, and hemodynamically superior prosthetic valve stent designs have improved prosthetic valve durability, thereby broadening the valve replacement options for young and old alike.³ The advent of transcatheter valve replacement (TAVR procedures) has also quickly become a commercial reality and has proven to be safe and efficacious in numerous studies. The stunning early success of the TAVR approach has allowed this remarkable new option to become commonplace in many institutions in hospitals around the world.⁴ Most importantly, perhaps, is that transcatheter valvular interventions have provided very high-risk patients, such as the elderly or those with a myriad of threatening comorbidities, a viable new option to consider.

There are numerous issues the surgeon must consider when planning treatment strategies in the patient with combined valvular and CAD. It is uncommon for today’s surgeon to see a patient with simple aortic or mitral valvular disease who also has straightforward proximal CAD. Indeed, it is more often a patient presents with complex, acute valvular/ventricular pathology, with superimposed diffuse, CAD. The prevalence of presurgical interventional options means that patients now undergo more aggressive medical therapy and multiple intracoronary dilation attempts before being referred for surgical evaluation. As a result, they are often referred at an older age and with more complex comorbidities, with more diffuse disease, persistent dysrhythmias, and worsening ventricular function. This older, sicker cohort of patients now referred for surgery are understandably at much higher risk for postoperative morbidity and mortality than in previous eras. Consequently, contemporary surgeons often face difficult therapeutic dilemmas that usually requires a more flexible, systematic, and thoughtful approach. In fact, current decision-making is more often a result of multidisciplinary heart teams, utilizing broad, evidence-based data as a foundation for complex medical decisions.⁵

The pathophysiologic combination and interaction between valvular heart disease and associated CAD is complex. Progressive valvular heart disease clearly impacts ventricular function. The additional impact of CAD has synergistic potential to further affect ventricular morphology and physiology. In particular, the deterioration in contractile strength caused by myocardial infarction and subsequent regional wall motion injury causes progressive distortion of ventricular shape as the infarcted muscle compensates through tissue remodeling. Loss of contractile strength and remodeling after ischemic injury eventually leads to cavitary dilation, with resulting effects ...