Centre procedural volume and adverse in-hospital outcomes in patients undergoing percutaneous transvenous edge-to-edge mitral valve repair using MitraClip® in Germany

Aims: The number of transcatheter mitral valve repair (TMVr) procedures has increased substantially during the last years. A better understanding of the relationship between hospital volume of transcatheter transvenous mitral valve repairs using MitraClip® and patient outcomes may provide information for future policy decisions to improve patient management.

Methods and results: We analysed patient characteristics and in-hospital outcomes for all TMVr procedures using MitraClip® performed in Germany from 2011 to 2017. Hospitals were stratified according to centre volumes and patients were compared for baseline characteristics and adverse in-hospital events. Overall, 24 709 inpatients were treated during the observational period. Patients treated in centres with a volume of ≤10 procedures annually developed more often pulmonary embolism (odds ratio 2.22, 95% confidence interval 1.19-4.13; P = 0.012) compared to those treated in centres with a volume of >10 procedures annually, whereas no association of centre volume (≤10 or >10) was found with in-hospital mortality (P = 0.728). Although patients treated in centres with an annual volume >25 TMVr procedures had higher numbers of comorbidities compared to those treated in centres with an annual volume of ≤25 TMVr procedures, in-hospital mortality did not differ (3.6% vs. 3.5%, P = 0.485). Similarly, when centre volumes were stratified for ≤50 vs. >50 procedural volumes, no association with in-hospital mortality was recorded (P = 0.792). A lower rate of mitral valve surgery after MitraClip® was observed over time, particularly in high-volume centres.

Conclusion: Annual numbers of MitraClip® implantations increased from 2011 to 2017 in Germany, whereas in-hospital mortality remained stable. Although patients treated in high-volume centres had a more unfavourable risk profile, in-hospital mortality was comparable to that of low-volume centres.