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Impact of Atrial Fibrillation on Clinical Outcomes, Resource Utilization and Cost of Transcatheter Aortic Valve Replacement

Atrial fibrillation (AF) is present in >35% of patients with aortic stenosis who are referred for transcatheter aortic valve replacement (TAVR). Data on the differential impact of AF on the outcomes of TAVR are conflicting. A number of studies have shown no impact of AF on adjusted short-term morbidity and mortality after TAVR, but several others demonstrated higher rates of post-TAVR death, bleeding complications, stroke, and permanent pacemaker implantation in AF patients compared with those without AF. We sought to utilize a national real-world database to assess whether the presence of AF is associated with worse shortterm outcomes, resource utilization, and cost in patients undergoing TAVR. Data were obtained from the Agency for Healthcare Research and Quality Healthcare Cost and Utilization Project–Nationwide Inpatient Sample (NIS) files between January 1, 2012 and December 31, 2015. The data were queried to identify patients who underwent transfemoral (TAVR) using the International Classification of Diseases, 9th and 10th Revision, Clinical Modification codes. Patients with AF were then identified and compared with those without AF. We excluded transapical TAVRs because they are rarely performed in contemporary practice and carry a much higher risk of new-onset AF. The primary end point was in-hospital mortality and secondary end points included complications, discharge utilization of intermediate care, and length and cost of hospitalization. To account for potential confounding factors and reduce the effect of selection bias, a propensity score-matching model was developed using logistic regression to derive two matched groups for the comparative analysis. Patients who underwent transfemoral TAVR with or without AF were entered into a nearest neighbor 1:1 variable ratio, parallel, balanced propensity-matching model using a caliber of 0.01 to ensure perfect matching. To estimate the cost of hospitalization, the NIS data were merged with cost-to-charge ratios available from the Healthcare Cost and Utilization Project. We estimated the cost of each inpatient stay by multiplying the total hospital charge with cost-to-charge ratios. Outcomes were compared using the chi-square test for categorical variables and independent samples t-test for continuous variables. A type I error rate of <0.05 was considered statistically significant. All statistical analyses were performed using SPSS version 24 (IBM Corporation, Armonk, New York) and R, version 3.3.1. A total of 13,781 patients who underwent TAVR between 2012 and 2015 (weighted national estimate = 68,905) were identified in the NIS. After excluding transapical TAVRs (n = 1,953), 11,808 patients were included in our analysis, of whom 5,213 (44.1%) had AF. Compared with patients without AF, those with AF were older (82 ± 7 vs. 80 ± 9 years), were more likely to be of white race (85.4% vs. 90.3%), and had higher incidence of key morbidities including hypertension (81.1% vs. 79.8%), chronic renal disease (30% vs. 33.7%), conduction abnormalities (19% vs. 16.8%), anemia (22.2% vs. 23.5%), and vascular disease (24% vs. 25.3%) (p < 0.001 for all) (Table 1). The overall unadjusted in-hospital mortality was higher in patients with AF compared to patients without AF (3.6% vs. 2.9%, p < 0.001). Moreover, with the exception of the rate of new pacemaker implantation, patients with AF experienced higher incidences of key complications and had longer and costlier hospitalizations compared with patients without AF (Table 1). After propensity-score matching, patients with AF had more inhospital deaths (4.3% vs. 3.0%, p = 0.004), strokes (2.7% vs. 2.3%, p < 0.001), pacemaker implantations (12.9% vs. 11.3%, p = 0.04), and acute kidney injuries (20% vs. 15%, p < 0.001). Resource utilization parameters were all higher in the AF group who had a higher rate of non-home discharges (32% vs. 25.7%), longer mean length of stay (8 ± 6 vs. 6.3 ± 5 days), and higher mean cost of the hospitalization ($59,296 ± $32,741 vs. $54,434 ± $26,938) (p < 0.001 for all) (Table 1). The major findings of this focused analysis are the following: AF is prevalent among patients referred for TAVR. AF in patients referred for TAVR is associated with higher risk-adjusted rates of in-hospital death, stroke, permanent pacemaker implantation, and acute kidney injury. Patients with AF also experienced longer and costlier hospitalizations and were more likely to be discharged to intermediate care facilities.