Prognostic implications of atrial fibrillation in patients undergoing transcatheter mitral valve repair: A National Inpatient Sample Database Study

Background
Atrial fibrillation is frequently found in association with mitral regurgitation, often posing a potential risk for patients undergoing surgical mitral valve repair. Recently, transcatheter mitral valve repair (TMVR) has emerged as a minimally invasive option for selected high-surgical risk patients, demonstrating promising results. Nonetheless, due to the early stages of the procedure, little is known about the prognostic implications between AF and TMVR. Our study aims to review in-hospital mortality, length of stay and total hospital cost for AF patients undergoing TMVR.

Methods
We queried the National Inpatient Sample (NIS) to identify adult patients who underwent TMVR from 2010 – 2014 using ICD9-CM procedure coding. Patients were subsequently divided based on the presence of AF. Demographic characteristics, in-hospital mortality and healthcare resource use were extracted and compared between the two groups. Continuous variables were expressed using mean and standard deviation and categorical variables as frequencies in percentages. A comparison was made using Student's t-test for continuous variables and chi-square test for categorical variables. A univariate logistic regression was conducted to identify variables that were associated with in-hospital mortality. Variables with a univariate p-value less than 0.15 were included in the final multivariable logistic regression model. We used SPSS version 25.0 (Armonk, NY: IBM Corp.) for statistical analysis.

Results
A total of 2,581 adult patients who underwent TMVR, were identified and included in the study. Multivariate analysis indicated that AF was an independent predictor of in-hospital mortality (OR 2.159, 95% CI 1.165- 4.001, p=0.014). AF was associated with higher length of stay (6.72 vs 5.61 days, p=<0.0001) but there was no association with total hospital cost ($16, 2321.22 vs $15, 7620.09, p=0.229).

Conclusions
AF was associated with significantly increased in-hospital mortality and length of stay in patients undergoing TMVR, but total cost was not different between those with and without AF.