The Ross Procedure

The Ross Procedure is a type of specialized aortic valve surgery where the patient's diseased aortic valve is replaced with his or her own pulmonary valve. The othera referenca this procedure is called switch procedure The pulmonary valve is then replaced with cryopreserved cadaveric pulmonary valve. In children and young adults, or older particularly active patients, this procedure offers several advantages over traditional aortic valve replacement with manufactured prostheses.

History

The Ross procedure is named after Dr. Donald Ross - a pioneer in cardiac surgery in the UK - who proposed the procedure in 1962 and first performed it in 1967.

Indications

1. Hypoplasia of the aortic valve annulus in the neonate
2. Progressive stenosis of the aortic valve in infants and children
3. Multilevel left ventricular outflow tract obstruction in association with aortic valve stenosis not amenable to aortic valve repair that requires enlargement of the outflow tract
4. Aortic insufficiency as a complication of percutaneous balloon aortic valvuloplasty
5. Rheumatic aortic valve disease
6. Aortic valve endocarditis

Contraindications

1. Pulmonary valve pathology
2. Known genetic defects in fibrillin, elastin, or collagen in connective tissue disorders (eg, Marfan syndrome, Ehlers-Danlos syndrome)
3. Significant immune complex disease as a coexisting disease, especially if it is the etiology of the aortic valve disease. (eg, systemic lupus erythematosus, ankylosing spondylitis, Reiter disease)
4. Advanced 3-vessel coronary artery disease
5. Significant irreparable mitral valve pathology that requires mechanical valve replacement (considered a relative contraindication by many surgeons)
6. Significant dilatation of the aortic root in comparison to the pulmonary valve annulus associated with aortic regurgitation (considered a relative contraindication by many surgeons, whereas others may continue to offer the Ross procedure along with aortic annular reduction)

Advantages / Disadvantages
Advantages

1. Freedom from thromboembolism without the need for anticoagulation.
2. The valve grows as the patient grows (i.e. children).
3. Favourable hemodynamics.
4. No foreign material present in the valve.

Disadvantages

1. Single valve disease (aortic) treated with a two valve procedure (aortic and pulmonary).
2. Pulmonary valve replacement

Preoperative

Echocardiography is used preoperatively to assess the aortic valve pathology, levels of left ventricular outflow tract obstruction and associated cardiac abnormalities. The pulmonary valve is assessed for clinically significant regurgitation or any other pathology. Echocardiography is also useful for assessing the sizes of the aorta and pulmonary annulus. A disparity in size of more than 2-3 mm is likely to require augmentation or reduction in the diameter of the aortic annulus.

Procedures

All procedures are performed though midline sternotomy. Cardiopulmonary bypass is established via standard aortic and bicaval venous cannulation. The left ventricle is decompressed by venting through the right superior pulmonary vein. Mild hypothermia (32-34 º) is used with a combination of antegrade and retrograde cold blood cardioplegia. Antegrade cardioplegia is initially administered through the root and then by direct coronary artery cannulation at 20-minute intervals.
The aorta is transected 1.5 cm above the right coronary artery. The aortic valve is inspected and repaired, if possible. If the valve is not repairable, the leaflets are then completely excised and calcium is debrided if present. The main pulmonary artery is partially opened just proximal to the bifurcation, and the valve is inspected to ensure normal anatomy and function.
Once the decision is made to proceed with the Ross procedure, the coronary buttons are prepared. A generous rim of aorta is left around each ostium to allow for suturing to the pulmonary autograft later. The pulmonary artery is separated from the aorta up to the bifurcation and is completely divided. The autograft is harvested by placing a right-angled clamp through the valve and by bringing the tip through the infundibulum approximately 1 cm below the base of the cusps. The right ventricular outflow tract is then opened circumferentially using scissors. Once the dissection proceeds laterally, the left anterior descending artery and its first septal branch are at risk if meticulous dissection is not performed. Following harvesting of the autograft, retrograde cardioplegia is administered and small venous branches are cauterized or ligated in the bed of the harvested autograft.

Step 1: Measurement of the aortic and pulmonic valves

Step 2: The aorta and pulmonary artery are opened and the aortic and pulmonary valves are carefully inspected to determine if the Ross is an appropriate procedure.

Step 3: The diseased aortic valve is removed. Then, the pulmonary valve (autograft) is removed and placed in the aortic position.

Step 4: The autograft in sutured in place and the coronary arteries are re-attached.

Step 5: A pulmonary homograft is attached to the right ventricle outflow tract.

Step 6: The aorta is attached to the autograft and the pulmonary artery is attached to the homograft - the procedure is complete.

One of the main objections to the Ross procedure is the genesis of pulmonary valve disease in addition to aortic valve disease. Proponents have argued that biological valves implanted in the pulmonary position would be slow to develop dysfunction, and any dysfunction would be well tolerated due to the lower pressures in the right side of the heart. Survival of homografts in the pulmonary position is good (20-year freedom from reoperation of 80%), and homograft dysfunction is infrequently implicated in the observed morbidity and mortality.

Homografts (aortic or pulmonary) should be the replacement of choice; no other valve performed as well in the pulmonary position. Many homograft valves are sterilized with ethylene oxide or irradiation -- methods recognized to have deleterious effects on valve performance. The results of the pulmonary autograft procedure are likely to be superior with the use of fresh homograft valves.Today, cryopreservation is the method of choice for homograft preservation.

References :

1. Bahaaldin Alsoufi et al.2009.The Ross Procedure for treatment of Pediatric Aortic Valve Disease 
2. Cleveland Clinic. Ross Procedure. October 2011.
3. University of Southern California.The Ross Procedure. October 2011.
4. Wikipedia. Ross Procedure. October 2011. 

Other reference The Ross Procedur can look in Medscape