David Procedure - Indications, Procedure, Benefits, and Risks

Introduction:

The heart is the primary circulatory organ. Four valves control blood flow in the heart. The aortic valve separates the heart’s lower ventricle (chamber) and the body’s principal artery, i.e., the aorta. The aortic root contains the aortic valve. Various surgical procedures are done to correct aortic valve conditions. However, conventional surgeries are associated with an increased risk of complications. Hence, a minimally invasive surgical technique was devised called the David procedure.

What Is David Procedure?

David procedure is also called valve-sparing aortic root replacement. Conventional procedures remove the aortic valve. In David procedure, the aortic valve is spared. Only the aortic root is removed and the valve can be repaired or reimplanted. It reduces many risks linked with aortic valve replacement. However, this procedure is complex. Although done by an experienced cardiologist, it is not frequently performed. Two major techniques to replace the aortic root are;

1. Aortic valve reimplantation.

2. Aortic root remodeling.

Reimplantation is done in patients under 75 years, with a connective tissue disorder connected to an inherited condition.

What Are the Indications and Contraindications of David Procedure?

The indications of this procedure include:

1. Aortic Aneurysm: It is an abnormal widening of the aorta. It happens at the aortic root. Increased widening can result in aortic dissection or rupture. Aortic dissection occurs when the force of blood splits the artery layers causing blood to leak (aortic regurgitation). Aortic rupture results from the bursting of the aneurysm. It causes bleeding inside the body. David procedure is increasingly becoming the preferred modality for aortic aneurysm repair.

2. Dilated Aortic Sinuses with Ascending Aorta Aneurysm: Aortic sinuses are anatomic spaces at the aortic root. Ascending aorta is the initial part of the aorta. Therefore, aortic sinus dilation is a risk factor for an aneurysm. Hence, before the aneurysm forms, surgery can be done.

3. Aortic Insufficiency: It is a condition in which there is aortic valve dysfunction that causes blood leakage and wrong blood flow direction.

The most common cause of an aortic aneurysm is Marfan’s syndrome (a connective tissue disorder). David procedure also suits patients under 65 years with healthy aortic valves. It has an excellent outcome if the aortic valve has minimal damage and can be repaired. Some of the contraindications of the reimplantation procedure include:

1. Re-Do Surgery: Re-do surgery is recurrent heart surgery. It is indicated in those patients who have undergone previous heart surgery. In these patients, another surgery is required to maintain heart health and function.

2. Concomitant Cardiac Surgeries: Some patients need two or more cardiac procedures together. Some examples are coronary bypass and valve surgery. David procedure is contraindicated in such patients.

How Is David Procedure Performed?

• Before the surgery, the surgical preparation of the patient is important which includes blood tests, echocardiogram (echo), heart angiogram (heart blood vessels X-ray), computed tomography (CT; an imaging technique involving X-rays), and magnetic resonance imaging (MRI; an imaging technique involving magnetic field and radio waves) are done. The entire procedure takes about six hours.

• After general anesthesia administration, a small midline incision through the sternum (chest bone) is given.

• The heart and lungs are connected to a machine called the cardiopulmonary bypass. After the heart is accessed, the aortic valve and root are separated from the surrounding tissues.

• After aortic valve repair (if necessary), the damage in the aortic root is removed.

• A graft is used to replace the damaged part and the valve is reimplanted and sutured.

• The coronary arteries (heart arteries) and ascending aorta are connected to the graft.

• The patient is removed from the bypass machine, the chest incision is closed and an echo is performed to check heart function.

• The patient is advised to stay in the intensive care unit (ICU) for some days. Then, a repeat echo and CT are done to recheck the heart functioning. Full recovery can take six weeks.

Some modifications of the David procedure include:

1. Hegar’s Dilator: Hegar’s dilator is used to create new aortic sinuses. The surgeon creates new sinuses in the graft. Blood flow is increased as a result of the new sinuses. Valve leakage is also reduced.

2. Aortic Annulus Diameter Reduction: Aortic annulus is the fibrous tissue near the aortic valve. Abnormal dilation of the aortic annulus is also risky. Therefore, the aortic annulus diameter is reduced according to the patient’s body surface area. Hegar’s dilator is used to reduce the diameter.

What Are the Benefits and Risks of David Procedure?

Bentall procedure is the standard for valve replacement. It is done for combined conditions of ascending aorta and the aortic valve. A graft is used to replace the aortic valve. However, the David procedure has several advantages over the Bentall procedure:

1. Surgeons do not remove the aortic valve during the procedure. It is because preserving the aortic valve is better for many patients. In addition, after valve replacement, patients need a mechanical valve with medicines to prevent blood clotting (anticoagulant therapy). However, there is no need for anticoagulants after David procedure.

2. There is a very low risk of future valve surgery.

3. As the patient’s natural valve is spared, there is a lower risk of infection, blood clotting, bleeding, and stroke. Further, the risk of a leaky valve is also reduced.

4. A shorter hospital stay, less pain, and a lower need for blood transfusion are added benefits.

However, David procedure is a complicated surgery done by only skilled surgeons. Respiratory problems, bleeding, blood clots, graft infection, lung infection, kidney failure, and a need for a pacemaker are some uncommon risks. However, the risks depend upon the patient's health and the underlying medical condition.

What Is the Prognosis of David Procedure?

David procedure is successful in about 95 percent of the cases. More than 90 percent of patients do not need a second aortic valve surgery for at least ten years. Shrestha et al., in 2022, reported the outcome of the David procedure in 732 patients between 1993 to 2019 at their center. The authors noted that the David procedure is comparable to conventional surgery. However, they emphasized the role of meticulous bleeding cessation during David procedure. Further, minimal invasion ensures a better aesthetic outcome. For elderly patients, a quicker recovery is the main advantage.

Conclusion:

David procedure is a minimally invasive heart surgery in which the aortic root is removed and the valve can be repaired or reimplanted. Surgeons execute the valve-sparing aortic root replacement only after garnering immense experience. Combining minimal access with valve-sparing surgery facilitates patients toward a quicker recovery. However, careful patient selection is crucial for the long-term success of the procedure.