Respective role of surface electrocardiogram and His bundle recordings to assess the risk of atrioventricular block after transcatheter aortic valve replacement.

BACKGROUND: Atrioventricular block (AVB) is common after transcatheter aortic valve replacement (TAVR) and permanent pacemaker (PPM) implantation is needed in up to 30% of patients. Main predictors of long term AVB are electrocardiographic. The purpose of this study is to assess the prognostic value of serial HV intervals measured before and after TAVR to shorten the timing of PPM implantation. METHODS: His bundle recordings were performed before (HV1), immediately after TAVR (HV2) and at day 2 for Edwards Sapien (ES) and 5 for Medtronic CoreValve (CV) (HV3). PPM indications were high degree AVB before day 5 or prolonged HV interval ≥80ms at the last recording. High degree AVB after discharge was evaluated from the pacemaker memories and ECG at 1 and 6months. RESULTS: Data were obtained in 84 patients (33% CV and 67% ES). HV values were not associated with early or late AVB. PPM were implanted in 27 patients (34%) for documented AVB (n=17, 24%), prolonged HV interval (n=9) or sick sinus syndrome (n=1). Persistent complete AVB during the procedure and postoperative high degree AVB were the only perioperative factors associated with further long term occurrence of high degree AVB (p=0.001 and p<0.001). On multivariate analysis, only postoperative high degree AVB was significant (p=0.001). CONCLUSION: Pre- and post-operative HV measurements were not correlated with late AVB after TAVR. Perioperative persistent complete AVB and postoperative high degree AVB are the only factors to predict late AVB and should be considered for the decision of PPM implantation.

SERCA2a gene transfer prevents intimal proliferation in an organ culture of human internal mammary artery.

Coronary restenosis, a major complication of percutaneous balloon angioplasty, results from neointimal proliferation of vascular smooth muscle cells (VSMCs). The sarco/endoplasmic reticulum calcium ATPase 2a isoform (SERCA2a), specific to contractile VSMCs, has been reported previously to be involved in the control of the Ca(2+)-signaling pathways governing proliferation and migration. Moreover, SERCA2a gene transfer was reported to inhibit in vitro VSMC proliferation and to prevent neointimal thickening in a rat carotid injury model. The aim of this study was to evaluate the potential therapeutic interest of SERCA2a gene transfer for prevention of in-stent restenosis using a ex vivo model of human left internal mammary artery (hIMA) intimal thickening. Left hIMAs, obtained at the time of aorto-coronary bypass surgeries, were subjected to balloon dilatation followed by infection for 30 min with adenoviruses encoding either human SERCA2 and green fluorescence protein (GFP) or control gene (ß-galactosidase, ß-gal) and GFP. Proliferation of subendothelial VSMCs and neointimal thickening were observed in balloon-injured hIMA maintained 14 days in organ culture under constant pressure and perfusion. SERCA2a gene transfer prevented vascular remodeling and significantly (P<0.01, n=5) reduced neointimal thickening in injured arteries (intima/media ratio was 0.07±0.01 vs 0.40±0.03 in ß-gal-infected arteries). These findings could have potential implications for treatment of pathological in-stent restenosis.