Valve Surgery The function of the four heart valves is to maintain the forward flow of blood in the body. Each valve needs to open wide enough to allow blood to quickly flow through and close tight enough to prevent blood from flowing backward. When one or more valves fail to perform one of these functions, it has serious implications to the patient (see Chapter 1). Many patients undergo surgery to repair or replace heart valves. This surgery may be the only treatment performed (isolated valve surgery) or be done in combination with coronary artery bypass grafting (see Chapter 5) or other therapies (see Chapter 7). Many times, these patients have more comorbidities than patients who have surgery to treat coronary artery disease alone. Objectives In this chapter, you will learn: 1. Factors that influence the choice of tissue or mechanical valve 2. Why some valves are repaired and some are replaced 3. Postoperative implications of valve surgery VALVE SURGERY Valve surgery is truly an open heart surgery. Not only must the chest be opened and the heart accessed (see Chapter 5), but the surgeon must cut into the heart tissue itself to work on the valves. These surgeries are longer and more complicated that an isolated coronary artery bypass graft surgery, putting the patient at higher risk of complications. Because the atrial tissue is opened to access the valves, patients who undergo valve surgery are at much higher risk of developing atrial fibrillation post-op. They may also have myocardial edema post-op, which will prolong recovery time. TISSUE VERSUS MECHANICAL VALVE The choice of a tissue or mechanical valve is one made prior to surgery, when possible. This is a decision made between the surgeon and the patient and depends on a number of factors. The patient’s preference, age, lifestyle, occupation, and recreational activities should be taken into account when making the decision. Tissue Valve Tissue valves may be made from porcine (pork), bovine (cow), or human (homograft) tissue. Most of the tissue valves implanted are porcine or bovine, often with some manufactured component in addition to the tissue. Tissue valves are desirable for many patients because they do not require anticoagulation and are ideal for patients for whom anticoagulation is contraindicated. Traditionally, tissue valves have not been as durable as mechanical valves, so they have not been the best option for younger patients. However, advances in technology have produced tissue valves that can last up to 20 years. Mechanical Valves Mechanical valves are composed entirely of manufactured materials, such as metal alloys, carbon-based materials, and Dacron. There are several different types of mechanical valves. Because mechanical valves are long-lasting, they may be a good option for younger patients requiring valve replacement. However, mechanical valves are prone to clot formation, so patients will require anticoagulation as long as the valve is in place. This makes them a poor choice for the elderly, patients who cannot tolerate anticoagulation, and recipients who engage in activities (sports, occupations) that place them at high risk for trauma.
FAST FACTS in a NUTSHELL
Nurse Key
Fastest Nurse Insight Engine
