More Evidence of Worse Outcomes With New-Onset AFib After TAVR

Megan Brooks

October 18, 2019

Patients with no history of atrial fibrillation (AF) who develop it within a month of transcatheter aortic valve replacement (TAVR) have worse long-term outcomes than their peers with preexisting AF or no AF, a new study has found.

Mary Vaughan Sarrazin, PhD, University of Iowa Institute for Clinical and Translational Sciences, Iowa City, and colleagues identified 72,660 patients, age 65 and older, who underwent nonapical TAVR between 2014 and 2016 using Medicare inpatient claims.

History of AF was defined by diagnoses on claims during the 3 years before TAVR. New-onset AF was defined as occurrence of AF during the TAVR admission or within 30 days after TAVR in a patient with no prior history of AF.

About 41% of patients had preexisting AF and about 7% developed AF after TAVR, although the incidence declined to 5% in the last year of the study. The average age of all patients was around 82. Patients with preexisting AF had the highest burden of comorbidities.

The primary outcome of death due to any cause occurred in 32% of patients with new-onset AF, compared with 23% of those with preexisting AF and 13% of those without AF, after a median follow-up of 305 days.

After adjusting for patient characteristics and hospital TAVR volume, new-onset AF remained associated with higher all-cause mortality compared with no AF (hazard ratio [HR], 2.06; 95% confidence interval [CI], 1.92 - 2.20; P < .0001) and preexisting AF (HR, 1.35; 95% CI, 1.26 - 1.45; P < .001).

In an adjusted competing-risk analysis, new-onset AF as compared with preexisting AF was associated with a higher risk for bleeding (subdistribution HR [sHR], 1.66; 95% CI, 1.48 - 1.86), stroke (sHR, 1.92; 95% CI, 1.63 - 2.26), and heart failure admissions (sHR, 1.98; 95% CI, 1.81 - 2.16, P < .01 for all). 

"While TAVR patients with preexisting AF are at higher risk of mortality compared to patients with no AF, new-onset AF carries a significantly worse prognosis and is associated with much higher mortality. This was despite that new-onset AF patients had a lower burden of most comorbidities at baseline," Sarrazin and colleagues write.

A study published this summer found that one in every two patients undergoing TAVR or surgical aortic valve replacement will develop new-onset AF and as a result face higher odds of in-hospital mortality, as reported by | Medscape Cardiology.

Sarrazin and colleagues say it's not entirely clear why new-onset AF is associated with worse outcomes. However, there is some evidence to suggest that in most patients with new-onset AF the new arrhythmia is related to the procedure injury itself.

Postulated mechanisms include acute perioperative injury and oxidative atrial stress, systemic inflammatory response after the procedure, acute left atrial volume overload, and stretch or lack of negative atrial remodeling after the procedure.

Limitations of their study include the lack of information about medications, which is especially relevant for anticoagulation, as it is known to affect outcomes of AF patients. The analysis also didn't differentiate between paroxysmal and permanent AF, and outcomes could be different between both types, the authors note.

Other limitations are the potential for misclassification of AF and the possibility of residual confounding from unmeasured factors, despite multivariate adjustment for relevant factors.

The authors say that further research is needed to determine the best prevention and management strategies for new-onset AF after TAVR to improve short- and long-term outcomes.

The study was published online October 16 in JACC Cardiovascular Interventions.

Concerning Results, Not an Isolated Event

In a related editorial, Troels Højsgaard Jørgensen, MD, and Lars Søndergaard, MD, DMSc, Rigshospitalet, Copenhagen University Hospital, Denmark, note that the risk for complications associated with TAVR has decreased during the past 10 years as the procedure as matured.

Yet TAVR remains "relatively new and is continuously changing as to further improve outcomes, which is imperative as TAVR will likely expand to even larger patient populations in the future," they write.

The results of this new study are "concerning" in that new-onset AF "does not seem to be an isolated event in relation to the peri-procedural period but indeed seems to warrant close follow-up," they conclude.

Jørgensen and Søndergaard find it interesting that the incidence of all measured complications during the TAVR hospitalization — including acute kidney injury, respiratory complications, need for transfusion, vascular complications, and stroke — was highest in patients with new-onset AF.

They point to a 2015 study that looked at baseline characteristics and prognostic implications of preexisting and new-onset AF after TAVR.

In that study, independent predictors for new-onset AF after TAVR were cardiovascular (myocardial infarction, arrhythmias, heart failure, or tamponade) or hemorrhagic procedure-related events. "Therefore, rather than being the result of new-onset AF induced by TAVR, it is possible that some complications may have resulted in the development of new-onset AF," Jørgensen and Søndergaard contend.

They also see the potential problem of not having data on oral anticoagulant (OAC) therapy in the study population, which makes it tough to infer whether the worse outcomes were due to not being on an oral anticoagulant.

It's possible that OAC therapy was omitted in some patients with new-onset AF after considering the risk for bleeding in these elderly TAVR patients.

Notably, a study published last year found that more than 70% of TAVR patients with new-onset AF where discharged without OAC therapy.

Funding for the current study was provided by the National Institute on Aging and the Department of Veterans Affairs. One author received grant support from Edwards Lifesciences and Boston Scientific. The remaining authors and the editorial writers  have disclosed no relevant financial relationships.

JACC Cardiovasc Interv. 2019;DOI:10.1016/j.jcin.2019.06.019 and DOI:10.1016/j.jcin.2019.07.008. Abstract, Editorial

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