A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: which is the best tissue valve for use in the pulmonary position, late after previous repair of tetralogy of Fallot? Altogether 141 papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. In addition to this, 1 paper was found by searching the reference lists of the relevant papers. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude from the best evidence available that homograft valves function well in the pulmonary position late after Tetralogy of Fallot (TOF) repair. This is particularly evident in the larger studies where the patients were only treated with homografts. It has been suggested that Homografts are better than xenografts and this has not been statistically shown. Two articles have suggested that xenografts outperform homografts however, in both studies these results were not statistically significant. Furthermore, early indications suggest that porcine valves may be better than bovine pericardial valves but a better longer term follow-up is certainly required to demonstrate this. It is important to realize also that when comparing the effectiveness of these valves in the pulmonary position, one cannot ignore confounding factors. The most important of these include timing of operation, age of patient, valve size, immunological factors, operative complexity and also postoperative valvular gradients. The timing of these operations has always been an area of great controversy illustrated by varied guidelines. There is no general consensus regarding whether there is even a role of pulmonary valve replacement late after TOF repair. Further weakening any conclusions that may be drawn based on current best evidence is the lack of strong follow-up data (transvalvular gradients and right ventricular (RV) volumetric data). New research is required with comparisons using objective clinical parameters in order to more effectively answer our clinical question.
Keywords: Bovine pericardial; Complication; Durability; Homograft; Mortality; Outcome; Porcine; Pulmonary valve replacement; Survival; Tetralogy of Fallot; Xenograft.