A-fib Common After Aortic Valve Replacement

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Atrial fibrillation (A-fib) is a relatively common complication of both surgical and transcatheter-based aortic valve replacement (AVR), according to a single-center, retrospective cohort study appearing online January 29, 2014, ahead of print in the Journal of the American College of Cardiology. The patients most likely to experience the condition are those whose procedures involve a pericardiotomy.

Researchers led by Robert J. Myerburg, MD, of the University of Miami Miller School of Medicine (Miami, FL), reported results on 123 patients undergoing AVR for severe, symptomatic degenerative aortic stenosis at their institution between March 2010 and September 2012. Procedures were split between surgical valve replacement (SAVR; n = 82) and TAVR (n = 149) with a balloon-expandable Sapien or Sapien XT valve (Edwards Lifesciences, Irvine, CA).

At 30-day follow-up (available in 92% of patients), A-fib occurred in 52 patients (42.3%), more often with SAVR (60%) than TAVR (35%).

Lowest A-fib Risk: Transfemoral TAVR

The highest likelihood of A-fib was with SAVR, while transfemoral TAVR showed markedly lower rates of A-fib, and procedures without pericardiotomy were associated with the lowest incidence (table 1).

Table 1. A-fib Incidence According to Procedural Characteristics

New-onset A-fib occurred at a median time of 53 hours—56 hours in the SAVR group and 52 hours in the TAVR group. More than half of A-fib episodes lasted less than 24 hours and spontaneously resolved. Twenty-five patients received amiodarone, including 2 patients who eventually underwent successful electrical cardioversion. Conversion after administration of amiodarone occurred in the majority of patients who received the drug, but 11 patients remained in A-fib at the time of discharge and 7 remained in A-fib at 30-day follow-up.

All patients who developed new-onset A-fib had CHA2DS2-VASc scores of at least 2 with a median score of 5.5. On multivariable analysis, transfemoral TAVR was associated with an 82% decrease in risk of A-fib compared with SAVR (OR 0.18; 95% CI 0.04-0.81), as were procedures without pericardiotomy (OR 0.18; 95% CI 0.05-0.59) compared with procedures using the technique.

There were no episodes of systemic embolism or hemorrhagic stroke.

The authors note that while the characteristics of new-onset A-fib were similar among each of the subgroups according to access route, transfemoral TAVR is the only procedure involving solely percutaneous access, while transapical and transaortic TAVR involve minimally invasive surgery through left lateral and upper midline thoracotomy, respectively.

Advanced Age, Comorbidities of SAVR Group Notable

Still, the SAVR group was marked by the highest rate of new-onset A-fib. “This is possibly due to the advanced age [82.11 years], multiple comorbidities, lack of preoperative pharmacologic interventions, and increased surveillance with continuous telemetry monitoring in our cohort,” the authors note.

In an accompanying editorial, Philip S. Cuculich, MD, and Daniel H. Cooper, MD, both of Barnes-Jewish Hospital (Saint Louis, MO), note that the main drawback to the study is the inherent biases of nonrandomized treatment arms, specifically patient selection for SAVR and TAVR. “The criteria for choosing patients for TAVR. . . clearly chooses a less healthy and older group of patients,” Drs. Cuculich and Cooper write. “Nevertheless, the highest [postoperative A-fib] incidence occurred in the group that was self-selected to be younger and healthier, which seems to strengthen the validity of the authors’ observations.” Decisions about the relative merits of SAVR vs TAVR and between types of TAVR “should include data from this study,” the editorial concludes.

In an email communication with TCTMD, Josep Rodés-Cabau, MD, of the Quebec Heart and Lung Institute (Quebec, Canada), indicated he was not surprised at the findings, and that the results are what he would expect for the incidence of new-onset A-fib following TAVR. “However,” he amended, “the incidence of new-onset A-fib in [transaortic-] TAVR patients was higher than in previous studies.  [This fact] is probably the most original aspect of the study.”

In terms of advice for clinicians, “ECG monitoring within the days following TAVR remains important,” Dr. Rodés-Cabau advised. “Previous data suggested that anticoagulation should be started upon the diagnosis of the arrhythmia in order to prevent cerebrovascular events, and this study goes in the same direction.”

Overall, “studies on the prevention of new-onset A-fib in cohorts at risk (transapical TAVR, SAVR) are warranted,” he concluded.

Study Details

The mean age of the cohort was almost 85 years (84.91). Patients did not receive routine pre- or perioperative anti-arrhythmic agents to prevent or decrease the occurrence of new-onset A-fib. However, all surgical patients received prophylactic atrial pacing for at least 24 hours postoperatively.

 

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Sources:
1. Tanawuttiwat T, O’Neill BP, Cohen MG, et al. New-onset atrial fibrillation after aortic valve replacement: Comparison of transfemoral, transapical, transaortic and surgical approaches. J Am Coll Cardiol. 2014;Epub ahead of print.

2. Cuculich PS, Cooper DH. Pericardial invasion: Lessons learned from SAVR and TAVR. J Am Coll Cardiol. 2014;Epub ahead of print.

Disclosures:

• Drs. Rodés-Cabau, Myerburg, Cuculich, and Cooper report no relevant conflicts of interest.