Atrial fibrillation may contribute to worse outcomes among patients undergoing TAVR

Patients undergoing transcatheter aortic valve replacement (TAVR) who had pre-existing or new-onset atrial fibrillation had higher rates of all-cause mortality, cardiac mortality and bleeding events compared with those who did not have atrial fibrillation, according to a registry analysis.

Lead researcher Giuseppe Tarantini, MD, PHD, of the University Hospital of Padova in Italy, and colleagues published their results online in the Journal of the American College of Cardiology: Cardiovascular Interventions on April 13.

The researchers evaluated 2,688 high surgical risk patients with severe, symptomatic aortic stenosis who enrolled in the prospective, observational SOURCE XT registry. The patients underwent TAVR with the Sapien XT valve (Edwards Lifesicences) at 99 sites in 17 countries. Edwards Lifesciences supported the registry.

The FDA has approved the Sapien XT valve for inoperable and high-risk patients with severe aortic stenosis, aortic valve-in-valve procedures and pulmonic valve replacement procedures.

Of the patients, 62.7 percent underwent TAVR via transfemoral access, 33.3 percent underwent TAVR via the transapical access, 3.8 percent underwent TAVR via direct transaortic access and 0.3 percent underwent TAVR via trans-subclavian access.

At baseline, 35.6 percent of patients had atrial fibrillation, including 41.8 percent who were treated using the transapical approach and 32.7 percent who were treated using the transfemoral approach.

Within 30 days of undergoing TAVR, 7.2 percent of patients had new-onset atrial fibrillation. Patients with new-onset atrial fibrillation had higher rates of transapical access, use of the largest prosthetic valve size, general anesthesia, balloon pre- or post-dilation, technical success and device success compared with patients who had pre-existing or no atrial fibrillation.

Of the patients with atrial fibrillation, those with new-onset disease trended toward an association with increased all- cause mortality and combined all-cause mortality and stroke compared with those with pre-existing disease. Patients with new-onset atrial fibrillation also had a higher incidence of bleeding and renal impairment compared with the pre-existing group.

The researchers added that patients treated using nontransfemoral approaches had a three-fold greater risk for new-onset atrial fibrillation compared with patients treated using the transfemoral approach.

A multivariable analysis found that new-onset and pre-existing atrial fibrillation were independent predictors on increased mortality at one year. However, atrial fibrillation was not an independent predictor of stroke or of death and stroke at one year. Only the patients with new-onset atrial fibrillation had a higher rate of stroke at two-year follow-up.

The independent predictors of new-onset atrial fibrillation were age. New York Heart Association class III or IV, nontransfemoral access route and balloon post-dilation of the prosthetic valve. The independent predictors of pre-existing atrial fibrillation were the presence of moderate to severe mitral regurgitation, moderate to severe tricuspid regurgitation and pulmonary hypertension.

The researchers cited a few limitations of the study, including that they may have underestimated the rate of atrial fibrillation or may have had overlap between new-onset and pre-existing atrial fibrillation because of the limited sensitivity used to assess atrial fibrillation. They also did not typically employ systematic, 72-hour continuous post-TAVR electrocardiographic monitoring and did not have information to differentiate paroxysmal from permanent atrial fibrillation at baseline.

Further, they mentioned that these results only applied to patients treated with a balloon-expandable prosthetic valve and may not be generalizable to other TAVR valves.

“We cannot exclude that our results were influenced by the higher baseline risk of [atrial fibrillation] sub-groups compared with those in sinus rhythm,” they wrote. “Notwithstanding, these results appear consistent with those of the multicenter FRANCE-2 and PARTNER studies, showing that [atrial fibrillation] had an independent detrimental effect on outcomes including cardiac death, bleeding, renal failure, and hospitalization. More data are needed to define the role of [atrial fibrillation] prevention and treatment on outcomes in these patients. Finally, the implementation of more comprehensive TAVR risk scores, taking into account [atrial fibrillation], remains a relevant clinical need.”