Risk factors for late pulmonary homograft stenosis after the Ross procedure

We reviewed our experience with the Ross procedure to identify the prevalence and predictors of late pulmonary homograft stenosis.

Between June 1992 and December 1997, 109 consecutive patients (age 34.5 +/- 8.6 years) underwent the Ross procedure, with reconstruction of the right ventricular outflow tract with a cryopreserved pulmonary homograft (22 to 30 mm diameter). There was one early and one late death. Echocardiographic follow-up was available in 105 of 108 patients (97%), with a follow-up of 39 +/- 20 months. Homograft donor and preservation measurements and patient variables were subjected to multivariable analyses to identify independent predictors of late homograft performance.

The major physiopathologic finding was homograft stenosis. Peak systolic gradients across the homograft were 20 mm Hg or more in 30 of 105 patients (28.5%) and 40 mm Hg or more in 4 of 105 patients (3.8%). One patient required two re-replacements of her homograft for severe stenosis. Moderate or severe homograft insufficiency was noted in 10 of 105 patients (9.5%). The independent predictors of late pulmonary homograft stenosis were younger donor age (p = 0.03), shorter duration of cryopreservation (p = 0.01), and smaller homograft size (p = 0.06). Beating heart donor status, short homograft ischemic time, and other factors that have been shown to be associated with increased graft viability were associated with graft stenosis but did not reach statistical significance. However, mean gradients across the homograft were significantly related (p = 0.002) to the number of these risk factors in each patient.

Stenosis of the pulmonary homograft can be a significant problem following the Ross procedure, and was predicted by younger donor age and shorter duration of cryopreservation. These factors may be related to increased cellular viability, which might actually predispose to late homograft stenosis in a subgroup of patients.