Abstract
Background and aim
The need for permanent pacemaker implantation (PPMI) is a burdensome complication of transcatheter aortic valve replacement (TAVR). Calcium distribution in the aortic-valvular complex (AVC) and, more recently, membranous septum (MS) length seem to be surrogate markers for conduction abnormalities after specific last generation balloon and self-expandable expandable valves. We sough to evaluate whether such pre-procedural association remains across the entire device spectrum.
Methods
Single-centre prospective study of 239 consecutive patients (140 women, median age of 84) with severe symptomatic aortic stenosis patients who underwent ECG-gated contrast-enhanced multi-detector computed tomography (MSCT) before TAVR since Jun/2017. Exclusion criteria were those with previous PPMI, previous bioprothesis, congenital bicuspid valve, and poor imaging quality. The J-score with an 850-Hounsfield unit threshold was used to detect areas of calcium in the region of interest. AVC was characterized by leaflet sector and region, using 3mensio Valves software 7.0 TM. An independent team retrospectively measured MS length blindly by determining the thinnest part of the interventricular septum in the coronal view in the better-defined systolic phase (usually at 40% of the R-R interval, Figure). Device selection (75.8% self-expandable devices, 20.1% balloon expandable, 3.1% other) and positioning were performed according to the operator criteria. Final implant depth was assessed based on the pre-release angiogram or final aortography.
Results
Mortality at 30-days was 1.3% and PPMI occurred in 43 patients (18%). Median MS length was 9.59mm (IQR: 3.11mm). After multivariable logistic regression analysis, MS length emerged as the single significant protective predictor for PPMI (OR: 0.14; 95% 95% CI: 0.05–0.42; p<0.001), independently of the device used (p<0.001). MS length showed strong discriminatory ability for PPMI (c-statistic 0.93; 95% CI 0.88–0.99). Sensitivity/specificity decision plots yielded an MS length of 6.9 mm as the optimal cut-off point for predicting the need for PPMI with a positive and negative predictive value of 91% and 93%, respectively (Figure). There wasn't any calcium accumulation within a specific region of AVC that independently predicted the outcome.
Conclusion
In our experience, a short membranous septum was strongly and independently associated with new permanent pacemaker implantation, regardless of the device type.
Our findings suggest that this simple measure should be routinely made to help device selection and implantation technique.
Funding Acknowledgement
Type of funding source: None
TCT-501 Impact of TAVR Implantation Technique on Need for Permanent Pacemaker Implantation
