Pulmonary Valve Replacement in Patients With Congenital Heart Disease: Is There Any Place for Mechanical Valves?

Background: We would report the results of 112 mechanical valve replacements in the position of pulmonary valve during 6 years in the Rajaie Heart Center. Material Methods: Between March 2004 and September 2010, 246 patients under- went pulmonary valve replacement for a congenital heart defect. In 112 cases (45.5%) a mechanical valve was implanted in the pulmonary position. These 112 patients were the subject of our retrospective descriptive study. All cases were followed on a pre- determined regular interval in our center (2 weeks, 3 6 months post-operatively and then every six months). Special attention was paid to RV function and prosthetic valvular performance by trans-thoracic and/or trans-esophageal echocardiography. Statistical analyses were performed using SPSS software (version 19). All data are presented as mean values ±standard deviation (SD) or percentages. The x2 test or the Fisher s exact test was used for the comparison of categorical variables. Student s T- test or Wilcoxon s signed rank tests were used for the comparison of parametric and non-parametric variables, respectively. Any P value of less than 0.05 was considered statistically significant. Results: Mean age: 21.8±9.06 yrs (Range: 3.5-58 yr). They consisted of 82 (73.2%) male and 30 (26.8%) female. TF was the most common basic lesion in 89 patients (86.4%). Mean time of follow-up was 27.27±16.16 months, (Range: 6-72 months). Mean duration of ICU and hospital stay was 3.17±3.14 days 10.12±6.13 days, re- spectively. A positive past history of Gore-Tex shunt was present in 21 (18.8%) and in 9 patients (8%) PVR was their first operation without prior history of any interven- tion. Dyspnea on exertion was the most common presenting symptom (82, 73.2%). Severe PI associated with RV-dysfunction was the most common indication for PVR. Ironically in 6 patients (5.4%), PVR was performed due to degeneration of previous biologic valve in the pulmonary position. Most patients had moderate RV dysfunction before operation (44, 39.3%). Post op hemorrhage requiring re-exploration was noted in 8 (7.2%). Prosthetic valve malfunction was present in 12 cases (10.8%); of whom, 8 (66.6%) improved with SK infusion and did not require re-operation. Redo surgery for valve replacement was required in 4(3.6%). Freedom from re-operation at 1 yr was 100% and at the mean follow-up period (27.27 months) was 96.4%. Mean interval between PVR and mal- function was 19.84±12.11 months. Other complications were as follows: Subdural hematoma in one (0.9%), GI complications in 2 (1.8%), Pulmonary complications in 7 (6.3%), Anticoagulation related hemorrhage in 3 (2.7%), post op arrhythmia in 5 (4.5%), superficial or deep wound infection in 2 (1.8%), HIT in one (0.9%), Warfarin toxicity in 2 (1.8%) patients. There was no evidence of thrombo-embolic complications. No post-op renal complication was noted. Post op mortality was observed in 4 (3.6%) which included one intra-operative (0.9%) and 3 in hospital mortality (2.7%).There was no statistically significant relationship between sex and post op complications. Again there was no significant relationship between sex and age with mortality. Post op LVEF as well as post op RV function improved following PVR (P=0.033 and, P=0.004 respectively). Conclusions: We do not confirm the bad reputation of mechanical valvular prosthesis in the pulmonary position in our center; on the contrary they perform well and potentially results in lower re-operation rate than can be expected after bio- prosthesis usage. No thrombo-embolic complications were noted. Crucial is anti-thrombotic therapy with Coumadin’s, maintaining an INR of 2.5-4. Therefore mechanical valvular replacement of the pulmonary valve may be considered as an alternative to biologic valves in patients with multiple previous operations and in patients requiring anticoagulation for other reasons, especially in this young age group.