Abstract 3085: Pre-stenting with a Bare Metal Stent before Percutaneous Pulmonary Valve Implantation Reduces the Risk of Stent Fractures
Background: Stent fractures are the most common complication after percutaneous pulmonary valve implantation (PPVI), with an incidence of 20%. In a third of these cases, stent fractures lead to recurrent right ventricular outflow tract (RVOT) obstruction and required re-intervention. A previous risk factor analysis indicated that a more rigid implantation site prevented this complication. We sought to analyze, whether pre-stenting with a bare metal stent (BMS) could reduce the incidence of stent fractures after PPVI.
Methods: Between September 2005 and June 2008, we studied 108 consecutive PPVI patients (PPVI only: n=54; BMS + PPVI: n=54). All patients underwent biplane chest X-ray, echocardiography and clinical evaluation during protocolized follow-up (1, 3, 6 and 12 months post procedure and yearly thereafter). The primary endpoint was PPVI stent fracture of any type. Data on the previously identified risk factors for stent fractures were collected in all patients. Hazard ratios (HR) were calculated from a multivariate Cox regression analysis. Subsequently, probabilities for the primary endpoint were obtained from a logistic regression model.
Results: In this series, the overall incidence of stent fractures was 14/108 (13%). Two factors were associated with a lower incidence of stent fractures: pre-stenting with BMS (HR 0.22, P=0.03) and calcifications along the implantation site (HR 0.19, P<0.01); one factor was associated with a higher incidence of stent fractures: recoil of PPV during balloon deflation (HR 16.3, P<0.01). According to these factors, performing pre-stenting with BMS could reduce the probability of developing stent fractures after PPVI in all patients, with the effect size depending on the individual risk profile. In the group with the lowest risk (i.e. presence of RVOT calcifications and no PPV recoil), the risk could be reduced by 6% (from 7% to 1%), in the low-risk group by 24% (from 31% to 7%), in the medium-risk group by 40% (from 65% to 25%) and in the group with the highest risk (i.e. no RVOT calcifications and PPVI recoil) by 26% (from 91% to 65%).
Conclusions: Pre-stenting with BMS is associated with a lower incidence of stent fractures after PPVI and may represent a clinically applicable strategy to improve patient outcome.