Fernando De-Torres-Alba (Division of Adult Congenital and Valvular Heart Disease, Department of Cardiovascular Medicine, University Hospital Muenster, Muenster, Germany) and others report in JACC: Cardiovascular Interventions that Sapien 3 (Edwards Lifesciences) is associated with a significantly higher rate of pacemaker implantation than is the earlier generation device, Sapien XT. They add that this higher rate of pacemaker implantation is associated with the implantation height of the device.
De-Torres-Alba et al comment that the transcatheter aortic valve implantation (TAVI) device Sapien 3 has significantly reduced the rate of paravalvular regurgitation compared with the earlier generation Sapien XT device, noting that Sapien 3 “incorporates a new adaptive external tissue seal aimed to reduce paravalvular regurgitation and its newly designed stent allowing for a lower delivery profile is 3mm to 4mm longer than the XT model”. However, they add Sapien 3 is associated with a pacemaker implantation rate of 13.3% whereas Sapien XT is associated with a pacemaker implantation rate of 6%. “The longer stent of the Sapien 3 valve that may extend deeper into the left ventricle outflow tract may also result in a higher rate of atrioventricular conduction abnormalities [and consequently, pacemaker implantation] compared to the previous valve generation,” De-Torres-Alba et al suggest.
As this difference in pacemaker rate between Sapien 3 and Sapien XT has not been directly assessed, the authors compared pacemaker rates between patients undergoing TAVI with Sapien 3 with those of patients undergoing TAVI with Sapien XT. They also sought to identify risk factors for development of atrioventricular conduction abnormalities and requirement of pacemaker implantation after Sapien 3 implantation “considering in particular, the role of the implantation height of the valve”.
Of 449 patients in the study, 162 received the Sapien 3 valve and 287 received the Sapien XT valve. There were no significant differences in age, gender, baseline risk profile, or pre-existing conduction abnormalities between groups. The rate of paravalvular regurgitation was significantly reduced in the Sapien 3 group. For example, while 2.8% of patients in the Sapien XT group had moderate or severe paravalvular leak, no patients in the Sapien 3 group had this complication.
However, the rate of new atrioventricular conduction abnormalities was significantly higher in the Sapien 3 group (39% vs. 28.9% for Sapien XT; p=0.022) as was the rate of pacemaker implantation (19.1% vs. 12.2% respectively; p=0.049).
De-Torres-Alba et al report: “The results of the propensity score analysis were consistent with the results of the unmatched analysis, confirming a significant difference in pacemaker implantation rates (12.6% in the Sapien XT group and 22.1% in the Sapien 3 group; p=0.017).” They add that this finding suggests that Sapien 3, which was designed to overcome the limitations of earlier generations, “may indeed successfully reduce one complication but at the expense of increasing another one.”
Exploring the potential reasons for the increased rate of pacemaker implantation with Sapien 3, the authors found that the mean implantation height of the valve was significantly lower in patients the Sapien 3 group who required a pacemaker: 67/33% aortic/ventricular stent expansion vs. 72/28% aortic/ventricular stent expansion (p=0.032). After observing a trend towards an increased implantation height of Sapien 3 over time in the study, De-Torres-Alba et al compared pacemaker rates between the first half of patients in the study to receive the valve with those of the second half. They state: “The significant increase in implantation height from 68%/32% to 75%/25% aortic/ventricular extension (p<0.0001) was associated with a significant decrease in the pacemaker implantation rate from 25.9% to 12.3% (p=0.028).”
Study author Helmut Baumgartner (Division of Adult Congenital and Valvular Heart Disease, Department of Cardiovascular Medicine, University Hospital Muenster, Muenster, Germany) told Cardiovascular News: “With correct placement of the Sapien 3 valve, the pacemaker rate is not higher than for Sapien XT. The clinical implication of our study is that the Sapien 3 valve should implanted with at least 70% of the stent length above the annulus to avoid atrioventricular block and the requirement of pacemaker implantation.”