Transcatheter aortic valve implantation (TAVI) is a well-established alternative to surgery for the treatment of patients with severe symptomatic aortic stenosis at high and intermediate surgical risk. Unfortunately, the occurrence of electrical conduction disturbances remains one of the most frequent complications of the procedure. The rate of permanent pacemaker implantation (PPI) after TAVI with new-generation devices is highly variable and appears to be influenced by several factors. While the impact of electrocardiographic and procedural predictors on PPI is well examined, there is still a lack of knowledge regarding anatomical predictors screened by multislice computed tomography (MSCT).

 

Hypothesis: 

Beside the well-known impact of ECG- and procedure-related factors on conduction disturbances, there are MSCT derived preprocedural values suggesting a higher risk for PPI after TAVI.

 

We performed a meta-analysis to summarize available studies that reported the incidence of PPI after TAVI with new-generation devices and provided raw data for preprocedural MSCT.

 

The authors conducted a literature search in PubMed database until March 31, 2020 to identify studies that investigated preprocedural MSCT data and rate of PPI following TAVI with new-generation devices. Ten observational studies (n=2707) met inclusion criteria for final analysis (46.1% self-expanding, 53.9% balloon-expanding devices). Effect size was estimated using random effects model with 95% confidence interval (CI). 

 

PPI was performed in 387 patients (14.3%) after TAVI, mostly due to high degree atrioventricular (AV) block (80.4%). The rate of PPI varied widely from 10% to 29% in individual studies. Regarding secondary endpoints’ analysis of relative risk (RR) and mean difference (MD) electrocardiographic PPI-predictors after TAVI appeared to be pre-existing right bundle branch block (RBBB) (RR 4.17; 95% CI 3.07-5.66; p<0.0001), AV block grade I (RR 1.71; 95% CI 1.13-2.59; p=0.01) and atrial fibrillation (AF) (RR 1.24; 95% CI 1.02-1.51; p=0.03). Patients requiring PPI had larger annulus perimeter (MD 1.66 mm; 95% CI 0.67-2.66 mm; p=0.001) and shorter membranous septum length (MD -1.1 mm; 95% CI -2.17-0.03 mm; p=0.04) assessed by preprocedural MSCT. Concerning calcium load of device landing zone, pacemaker dependent patients showed increased calcification of the non-coronary cusp (MD 39.76 mm3; 95% CI 18.60-60.93 mm3; p=0.0002), the left-coronary cusp (LCC) (MD 47.60 mm3; 95% CI 19.40-75.81 mm3; p=0.0009) and the total left ventricular outflow tract (LVOT) (MD 19.17 mm3; 95% CI 6.68-31.66 mm3; p=0.003). Lower implantation depth (MD 0.95 mm from NCC; 95% CI 0.09-1.80 mm; p=0.03) and oversizing by annulus diameter/area (MD 1.52%; 95% CI 0.11-2.93%; p=0.04) were procedural predictors of PPI following TAVI, while no differences could be observed regarding pre- and post-dilatation.

 

This structured meta-analysis proved PPI rate in 14.3% of patients following TAVI. Beside well-known electrocardiographic (AF, RBBB, AV block grade I) and procedural predictors (implantation depth, oversizing) this meta-analysis showed for the first time that MSCT derived anatomical values (annulus perimeter, membranous septum length) and distribution of device landing zone’s calcification (NCC, LCC, LVOT) are associated with increased risk of PPI following TAVI.