The primary long term risk of the Ross Procedure is the need for further surgery. Fortunately, this has been required in less than 10% of patients up to 10 years. Data are not sufficient to calculate the risk out to 20 years, but it is anticipated that 80% of patients will be free from re-operation up to that point in time. The following data are from Dr. Stelzer’s series of 421 patients. (It should be noted that the comprehensive collection of follow up data is currently in process and these numbers reflect only those patients of whom he has personal knowledge.)
Twenty-one patients have required re-operation for regurgitation of the (new) aortic valve. Four of these have been due to technical problems at the time of original surgery and two have been endocarditis. Two patients developed a degenerative disease of the leaflets and the whole pulmonary root. Nine patients developed dilatation of the new aortic root which caused the valve to leak. Four others had primary mitral regurgitation which required surgery and there was moderate aortic regurgitation that was not wise to leave alone. Of note, the two with endocarditis had both had active endocarditis at the time of first operation.
Only three patients have required surgery for the pulmonary homograft placed into the right ventricular outflow tract. One other had a balloon dilatation of the homograft. Four patients had further surgery for mitral regurgitation and two others needed coronary bypass grafting. All the repeat operations have been successful.
The fate of the homograft in the right ventricular outflow tract has been the subject of much interest since the very beginning. A small percentage of pulmonary homografts has developed an early narrowing problem just beyond the valve itself to the extent that replacing it becomes necessary. This may be due to a type of rejection phenomenon. This has led to re-operation in 1-2% of patients in other series. Because so few patients develop this problem, it is not reasonable to prescribe anti-rejection medication to everyone.
There is consistently some shrinkage of the inflow end of the homograft due to the natural scarring process where it is sewn to the right ventricular muscle. Some others develop enough narrowing to produce a pressure gradient and murmur. This pressure gradient is well tolerated up to about 50 mm Hg and can be assessed by echocardiogram, which can be used to follow the status of this situation fairly accurately.
Regurgitation from late deterioration of the homograft valve is well tolerated in the pulmonary position. Children with pulmonary stenosis were treated in the past with surgical removal of that valve and are now treated with balloon dilatation of the valve leaving it widely incompetent (i.e. the pulmonary valve is non-functional). These children have gone up to 20 years with no pulmonary valve at all. Ultimately, the right ventricle dilates but with the low pressures on this side of the heart, it takes a long time. If the homograft gives good service for 20 years and poor service for 20 more, the Ross procedure has the potential for 40 years of long-term durability without re-operation. Actuarial techniques applied to Mr. Ross’ series indicate that only 15% of patients will require a new pulmonary homograft within 20-25 years. New experimental technology has allowed percutaneous replacement of the pulmonary valve since 2005 and holds promise of further development to allow this technique to extend the life of the Ross even further if the homograft becomes a problem without further open surgery.
Technical failures are fewer than Mr. Ross’ experience with his original (freehand subcoronary failed in 30 of 131 or 23%) technique. Experience has shown that patients with primary aortic regurgitation and stretching (dilatation) of the annulus (the insertion point of the aortic valve) are at greatest risk for early and late failure. This is now addressed with steps to downsize the dilated annulus and fix it with unstretchable material to support the autograft properly. Late dilatation of the other (distal) end has taught us that this may also need support and/or downsizing (or even replacement) of the ascending aorta. This support should be kept as close as possible to the top of the valve itself without leaving excess pulmonary artery wall to stretch in a longitudinal direction. On rare occasions, the entire autograft is enclosed in a “jacket” of dacron graft material to prevent stretching of the Sinuses of Valsalva (side walls) if they appear particularly thin. In many patients it is possible to preserve native aortic wall tissue to incorporate around the outside of the autograft. This “native jacket” technique has been used extensively since 2001.