Surgical Aortic Valve Replacement (SAVR) is the traditional, open-heart procedure used to treat severe disease of the heart’s aortic valve. This valve acts as the exit door from the heart’s main pumping chamber, the left ventricle, into the aorta, the body’s largest artery. When the valve becomes dysfunctional, SAVR is performed to remove the damaged structure and replace it with a new prosthesis. This intervention restores proper blood flow and alleviates the strain placed on the heart muscle.
The Conditions Requiring Valve Replacement
The need for a Surgical Aortic Valve Replacement arises when the native valve fails to open or close correctly. Aortic stenosis occurs when the valve leaflets become stiff, thickened, or fused, often due to calcification, which severely narrows the valve opening. This narrowing forces the left ventricle to generate high pressure to push blood through the restricted opening, causing the heart muscle to thicken and weaken over time.
Aortic regurgitation occurs when the valve leaflets fail to close completely, allowing blood to leak backward into the left ventricle after each contraction. This backflow causes the ventricle to manage a larger volume of blood, which increases the heart’s workload and leads to chamber enlargement. Both stenosis and regurgitation can lead to symptoms like chest pain, fainting, and shortness of breath. The goal of SAVR is to relieve this stress on the heart muscle before irreversible damage occurs.
Performing the Surgical Aortic Valve Replacement
The SAVR procedure begins with the patient under general anesthesia. The cardiac surgeon then performs a sternotomy, which involves making a vertical incision down the center of the chest and dividing the breastbone to gain direct access to the heart.
The patient is then connected to a heart-lung bypass machine, also known as cardiopulmonary bypass. This device temporarily takes over the function of the heart and the lungs, circulating and oxygenating the blood while the surgical team operates. The heart is cooled and stopped using a specialized solution, creating a still, bloodless field for the valve replacement.
Once the heart is stopped, the surgeon opens the aorta to expose the diseased aortic valve. The calcified or damaged native valve is excised, and the replacement valve is then sewn into the aortic annulus, the fibrous ring where the valve sits. The new valve must be securely fixed to prevent leaks and ensure optimal function.
After the new valve is secured, the aorta is closed, and the patient is gradually weaned off the heart-lung machine. The heart is warmed and allowed to restart its normal rhythm, and the bypass machine is disconnected. The surgeon then uses surgical wires to bring the two halves of the breastbone back together before closing the chest incision with sutures. The entire process typically takes between two and four hours.
Options for the Replacement Valve
The selection of the prosthetic valve is a key step in preparing for SAVR, with the choice between a mechanical valve or a bioprosthetic valve. Mechanical valves are engineered from durable, synthetic materials, such as carbon and metal, and are known for their longevity, often lasting the patient’s lifetime. Their primary drawback is the risk of blood clots forming, which necessitates the patient taking lifelong anticoagulant medication, such as warfarin, to thin the blood.
Bioprosthetic, or tissue, valves are constructed from animal tissue, typically sourced from pigs or cows, and mounted onto a supportive frame. These valves generally do not require long-term blood thinner medication. However, tissue valves are subject to structural deterioration over time; while they usually last at least ten to fifteen years, they may require a future replacement operation.
The choice between these two valve types depends on the patient’s age, lifestyle, and willingness to commit to lifelong anticoagulant therapy. Mechanical valves are often preferred for younger patients due to their durability, while bioprosthetic valves are commonly recommended for older individuals or those for whom blood thinners pose a significant risk.
Immediate Recovery and Long-Term Outlook
Following the surgical procedure, the patient is transferred to the intensive care unit (ICU). Most patients spend one to two days in the ICU before moving to a regular hospital room. The hospital stay after SAVR is approximately five to seven days.
During the hospital stay, early mobility is encouraged, with patients being assisted to walk short distances. Pain management is a focus during this period, with medications administered to control discomfort from the chest incision. The recovery process continues at home, often involving a period of cardiac rehabilitation.
The long-term prognosis after a successful SAVR is excellent, resulting in improvement in the patient’s quality of life and symptom relief. For low-risk patients, long-term survival rates are high, with studies showing five-year survival rates around 93%. Patients require ongoing monitoring, including regular echocardiograms to assess the function of the new valve and manage necessary medications specific to the type of prosthesis implanted.