In-hospital complications after MitraClip in patients with heart failure and preserved versus reduced ejection fraction in the United States

Background: The clinical benefits of transcatheter edge to edge mitral valve repair have been well established in patients with heart failure and severe mitral regurgitation (MR) who have prohibitive surgical risk. In March of 2019, the FDA approved the MitraClip for treatment of selected patients with HF and severe secondary MR. However, the relative outcomes of patients with HFrEF and HFpEF treated with MitraClip are largely unknown. We therefore sought to investigate the incidence and characteristics of in-hospital mortality in patients with HFpEF and HFrEF following MitraClip. Methods: The study sample analyzed was originated from the National Inpatient Sample (NIS) registry which includes data from hospitalized patients in the United States (US) between January 1, 2012 and December 31, 2020. Data were extracted from the entire NIS registry using ICD-9 codes. Patients with the primary or secondary diagnosis of MitraClip were identified. Hospitalizations for HFpEF and HFrEF were identified based on ICD-9-CM and ICD-10-CM codes. Demographics, conventional risk factors, and in-hospital outcomes were evaluated. Results: 23,260 hospitalizations for MitraClip implantation between 2016 and 2020 were analyzed. The HFrEF group had higher absolute rates of complications as well as a higher observed in-hospital mortality (2.4 % vs 1.7 %; OR 0.75 95 % CI 0.44–1.26; p 0.28) which did not meet statistical significance. Absolute rates of acute myocardial infarction (AMI), acute kidney injury (AKI) and respiratory failure necessitating invasive mechanical ventilation were observed to be higher among HFrEF patients. Post-procedural shock was significantly more common in patients with HFrEF (9.0 % vs 2.8 %: OR 0.34 95 % CI 0.25–0.48 p < 0.001). Significantly longer hospitalizations were observed in the HFrEF cohort (5.3 ± 11.2 days vs 4.2 ± 7.3 days; p < 0.001) as well as a higher total hospitalization cost (61,723 ± 56,728 USD vs 57,278 ± 46,143). Conclusions: In the present study of US patients, those with HFrEF were observed to have statistically higher risk of in-hospital post-procedural shock and longer hospitalization length of stay when compared with patients with HFpEF who underwent MitraClip implantation. Additionally, patients with HFrEF undergoing MitraClip procedure were observed to have higher absolute rates of certain post-procedural complications, however these observations did not reach statistical significance. Understanding of the aforementioned differences after MitraClip implantation may be useful in-patient selection, prognostic guidance, and hypothesis generation to propel future large clinical studies.