Impact of ESRD on In-ospital Mortality After Transcatheter Mitral Valve Repair: A National Inpatient Sample Database Study

Background
Prevalence of mitral regurgitation (MR) is substantially high in patients with renal disease, especially those requiring hemodialysis. Complex challenges are faced once valvular replacement is required due to the comorbidity burden and elevated risk of post-operative complications. Transcatheter mitral valve repair (TMVR) is changing the treatment paradigm among patients with MR and is intended for those in whom surgery is considered not feasible due to the presence of risk factors that may preclude favorable outcomes. Nonetheless, due to the early stages of the procedure, little is known about its use in patients with specific conditions such as end-stage renal disease (ESRD). Our study aims to review in-hospital mortality and length of hospital stays for ESRD 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 ESRD. Demographic characteristics, in-hospital mortality, and length of hospital stays 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. Multivariate logistic regression analysis was performed to identify independent risk factors for in-hospital mortality. We used SPSS version 25.0 (Armonk, NY: IBM Corp.) for statistical analysis.

Results
We identified 2,581 adult patients who underwent TMVR, of whom 75 (2.9%) were ESRD, and 2506 (97.1%) were non-ESRD. Individuals with ESRD had higher in-hospital mortality (6.7% vs. 2%, p=0.006) and higher length of stay (14 days vs. 6 days, p=<0.001) in comparison to non-ESRD patients. After adjustment for age, sex and co-morbidities with multivariate logistic regression analysis, ESRD remained an independent risk factor for in-hospital mortality (OR=3.33, p=0.018, CI: 1.23 – 9.02).

Conclusions
Presence of ESRD is associated with higher in-hospital mortality and increased the length of hospitalizations compared to non-ESRD patients.