PARIS – Aortomitral continuity calcification, a common finding on CT in patients undergoing transcatheter aortic valve replacement, predicts new-onset atrial fibrillation and the need for permanent pacemaker insertion, Marco Spaziano, MD, reported at the annual congress of the European Association of Percutaneous Cardiovascular Interventions.
“Increased surveillance for arrhythmias in the 30 days post TAVR is warranted in patients with aortomitral continuity calcification,” declared Dr. Spaziano of the Paris South Cardiovascular Institute in Massy, France.
Bruce Jancin/Frontline Medical News
Dr. Marco Spaziano
He presented a single-center retrospective study of 524 patients undergoing TAVR with a self-expandable or balloon-expandable device. Aortomitral continuity calcification (AMCC) was found on CT in 15.8% of them. Dr. Spaziano defined AMCC as the presence of calcium in the curtain linking the aortic and mitral valve annuli. The clinical implications of this common finding were unknown prior to this study.
The 83 patients with AMCC did not differ significantly from the 441 without that CT finding in terms of baseline demographics, Society of Thoracic Surgeons risk score, prevalence of peripheral vascular disease, QRS duration, left ventricular ejection fraction, complete left or right bundle branch block, or aortic valve calcification volume. The prevalence of atrial fibrillation at baseline was 25.6% in the AMCC group and closely similar at 26.3% in the group without AMCC. Sixteen percent of subjects in each group had a previous pacemaker.
Similarly, the two groups didn’t differ in terms of procedural characteristics, including device type, size, or depth of implantation, or need for a second valve, or annular rupture.
However, excluding from consideration the patients with prior AF, the incidence of new AF in the 30 days post-TAVR was 22.7% in patients with AMCC compared with just 7.6% in the no-AMCC group. In addition, 33% of patients with AMCC received a new permanent pacemaker, as did 21% of those with no AMCC.
Other key 30-day outcomes didn’t differ between the two populations, including rates of death, stroke, vascular complications, and moderate or severe paravalvular regurgitation.
In a multivariate regression analysis adjusted for age, sex, device type and implantation depth, preexisting right bundle branch block, and surgical risk score, AMCC was associated with a statistically significant 1.8-fold increased likelihood of new pacemaker insertion and a 3.4-fold greater risk of new AF.
Dr. Spaziano said that in brainstorming with electrophysiology and echocardiography colleagues, the group came up with two hypotheses to explain the study findings. One is that AMCC might be a biologic marker for concomitant mitral stenosis, a known strong predictor of AF.
“Oftentimes it’s very difficult to diagnose mitral stenosis when there is aortic stenosis, because of left ventricular compliance issues, so potentially the patients with this calcium ridge may also have mitral stenosis,” he observed.
The other proposed hypothesis is that AMCC reflects increased calcification and fibrosis in the electrical system of both the AV node and atrium, with a resultant increased risk of developing new AF after the TAVR procedure.
Session chair Mohammad Abdelghani, MD, wasn’t buying either hypothesis. If either were correct, the group with AMCC would be expected to have a higher baseline rate of AF preprocedurally, observed Dr. Abdelghani of the Academic Medical Center at Amsterdam.
He suggested an alternative explanation on the basis of a German study that showed patients with significant calcification of the left coronary cusp were at sixfold greater risk for pacemaker implantation post TAVR. He proposed that calcification in the left sector of the valve landing zone causes the device to end up being positioned a bit off-line.
“I think the device protrudes away from the calcium and towards the right coronary artery commisure, compressing the conduction system that we know lies there,” Dr. Abdelghani said.
Dr. Spaziano reported having no financial conflicts of interest regarding his study.