Aortic stenosis surgery procedure


 * Associate Editor-In-Chief: Mohammed A. Sbeih, M.D. [mailto:msbeih@perfuse.org], Claudia P. Hochberg, M.D. [mailto:chochber@bidmc.harvard.edu], Abdul-Rahman Arabi, M.D. [mailto:abdarabi@yahoo.com], Keri Shafer, M.D. [mailto:kshafer@bidmc.harvard.edu], Priyamvada Singh, MBBS [mailto:psingh@perfuse.org]; Assistant Editor-In-Chief: Kristin Feeney, B.S. [mailto:kfeeney@perfuse.org]

Overview
The Procedure can be done either by the traditional open heart surgery or by the Minimally invasive surgery. Before the surgery, the patient will receive general anesthesia. This will make the patient asleep and pain-free during the entire procedure. Other than the aortic valve replacement surgery; aortic stenosis could be treated by:
 * Percutaneous Aortic Balloon Valvotomy.
 * Transcatheter Aortic Valve Implantation.

Aortic Valve Replacement Procedure
If the procedure is indicated; it could be done by one of the following approaches:

The Traditional Open Heart Surgery:


 * The surgeon will make a 10-inch-long cut in the middle of the chest (sternum).
 * Next, the surgeon will separate the breastbone (sternum) to be able to see the heart.
 * Most people are connected to a heart-lung bypass machine or bypass pump. The heart is stopped while the patient is connected to this machine. This machine does the work of the heart while the heart is stopped.
 * A small cut is made in the left side of the heart so the surgeon can repair or replace the aortic valve.

In Minimally Invasive Aortic Valve Surgery; there are several different ways to perform the procedure:


 * The heart surgeon may make a 2-inch to 3-inch-long cut in the right part of the patient's chest near the sternum. Muscles in the area will be divided so the surgeon can reach the heart. A small cut is made in the left side of the heart so the surgeon can replace the aortic valve.
 * In Endoscopic surgery; the surgeon makes one to four small holes in the chest, then he or she uses special instruments and a camera to do the surgery.
 * For Robotically-Assisted Valve Surgery, the surgeon makes two to four tiny cuts (about a ½ to a ¾ inch) in the chest. The surgeon uses a special computer to control robotic arms during the surgery. The surgeon sees a three-dimensional view of the heart and mitral valve on the computer. This method is very precise.

The patient may or may not need to be on a heart-lung machine for these types of surgery, but if not; the heart rate will be slowed by medicine or a mechanical device.

There are two types of valves that can be used :

1. Mechanical which is made of man-made (synthetic) materials, such as a metal like titanium. These valves last the longest, but the patient will need to take blood-thinning medicine, such as warfarin (Coumadin) or aspirin, for the rest of his or her life.

2. Biological which made of human or animal tissue. These valves last 10 to 12 years, but the patient may not need to take blood thinners for life.

The 2006 American College of Cardiology/American Heart Association (ACC/AHA) recommendations for the choice of aortic valve :


 * If the patient is under 65 years of age and do not have a contraindication to anticoagulation then mechanical valve is preferred.
 * If the patient is ≥65 years of age who do not have risk factors for thromboembolism; Bioprosthetic valve will be reasonable.
 * If the patient has already a mechanical valve in the mitral or tricuspid position (need anticoagulation).
 * If the patient has active prosthetic valve endocarditis; the valve should be replaced.
 * If the patient has contraindications to anticoagulation therapy regardless his or her age; then a bioprosthetic valve is indicated.
 * In case of small oartic root; mechanical valve is indicated as there is a risk of annular enlargement in such patient if bioprosthetic valve is used.

Once the new or repaired valve is working, the surgeon will:
 * Close the heart and take you off the heart-lung machine.
 * Place catheters (tubes) around the heart to drain fluids that build up.
 * Close the sternum with stainless steel wires. It will take about 6 weeks for the bone to heal. The wires will stay inside the body.

The patient may have a temporary pacemaker connected to the heart until his or her natural heart rhythm returns.

The surgeon may also perform coronary artery bypass surgery at the same time, if needed.

Technique
The retrograde technique is the most commonly used technique.
 * 8 French femoral sheath can usually accommodate a 20 mm balloon and minimizes vascular complications
 * Alternatively two 6 Fr sheath from bilateral femoral approach and two smaller balloons can be used
 * The letter may be necessary in female elderly patients with concomitant peripheral vascular disease
 * 0.035” straight wire is commonly used to cross the valve and advance via pig-tail or Amplatz catheter; Right heart catheterization is done and transaortic gradient is typically measured pre-procedure
 * The 0.035” wire is then exchanged for a stiffer 0.038”Amplatz exchange length wire with the tip shaped into a pig-tail shape so as not to injure the LV
 * The 20-23 mmX 6 cm balloon is advance over the wire and positioned to straddle the aortic valve
 * The balloon is manually inflated with a 60 cc syringe containing diluted contrast (slowly)
 * Meticulous control of balloon position must be maintained at all times by backward traction on the balloon to prevent jumping forward and injuring/perforating the LV apex

The most preferable surgical closure method for this tenuous patient population is a perclose or angioseal closure. This particular closure method calls for a mandatory attention to the meticulous access technique. An antegrade approach may be a viable method in some patient populations. An example of such would be the venuous access with transseptal approach. This particular procedure can be done in a select population of patients. Many patients experience an adverse response to the hemodynamic effect of mitral valve incompetence. In this situation, the rigidity of the wire traveling across the mitral valve can directly result in mitral valve injury. It is, therefore, not an advisable treatment method for most populations.