Right ventricular outflow tract reconstruction with Medtronic Freestyle valve in the Ross procedure: A systematic review with meta-analysis

Cryopreserved pulmonary homografts (PH) are the current gold standard for right ventricular outflow tract (RVOT) reconstruction in the Ross procedure. Unfortunately, their use is limited by a relatively scarce availability and high cost. Porcine stentless xenografts (SX) such as the Medtronic Freestyle SX are increasingly being used, although it is unclear whether the hemodynamic performance and the long-term durability are satisfactory. The present systematic review followed the Preferred Reporting Items for Systematic reviews and Meta-Analysis statement. The pooled treatment effects were calculated using a weighted DerSimonian-Laird random-effects model. We also evaluated the effect of time after RVOT reconstruction on valve gradients using meta-regression. Six studies with a total of 156 patients met the inclusion criteria. The pooled estimates for the pooled follow-up of 37 months were: 1.3% operative mortality, 94.8% overall survival, 7.5% structural valve deterioration, 5.2% reintervention, 73.3% asymptomatic, and 1.5% moderate or severe pulmonary insufficiency. Peak valve gradients were significantly correlated with time after RVOT, increasing during follow-up. Three studies compared PH with SX, one concluded that the SX is an acceptable alternative for RVOT reconstruction, whereas two concluded that this valvular substitute had inferior performance. The Freestyle SX can be considered as an alternative to PH, although it might be associated with more reinterventions, higher peak valve pressure gradients, and pulmonary valve dysfunction.