DOI DOI https://doi.org/10.1007/s00392-021-01843-w
Severe mitral regurgitation is the second most common valvular heart disease. In recent years Transcatheter Mitral Valve Repair (TMVR) has become a frequently applied treatment option. Clinical reality demonstrates that not every patient experiences the same extent of improvement in cardiopulmonary resilience.
In this prospective, monocentric cohort-study our aim was to identify objective parameters that can predict clinical benefit after MitraClip®-procedure. Therefore, FT CMR and CPET were performed before and three months after TMVR and the findings correlated to clinical outcomes.
Results and Methods:
During a time period of 18 months (11/2016 – 05/2018) we included 33 patients with symptomatic mitral regurgitation that were planned to undergo minimal invasive mitral valve repair at the University of Ulm. FT CMR and CPET were performed before and after TMVR as well as clinical assessment. The follow-Up extended over a time period of 3-6 months. Clinical improvement was defined as a reduction of at least 2 pts on the NYHA-classification scale. The FT-CMR examination depicted a significant reduction of left ventricular diameter as noted in a decrease in end-diastolic volume (Pre (LVEDV): 133, 3 ± 62,2ml VS Post (LVEDV) 100, 4±51,2ml (p-value: 0, 0041) and Pre (LVEDi): 74, 5 ± 31,4ml VS. and Post (LVEDVi): 55, 8 ± 24,4ml (p-value: 0, 0032)). Regarding RV-Function we noted that pts. experiencing clinical improvement had no change in right RV-function (EF: (Pre) 0, 42 ± 0,1ml VS (Post): 0, 41±0,1ml (p-Wert: 0, 6) and RV_GLS: (Pre): -17, 4 ± 4, 8 VS. (Post):-17, 8 ± 5,8ml (p-value: 0, 7)) whereas pts. Lacking improvement had numerical worsening of RV-function (EF: (Pre) 0, 37± 0,17ml VS. (Post) 0, 35 ± 0,13ml (p-value: 0, 7) and RV_GLS :( Pre): -17, 09 ± 6, 7 VS. (Post):-14, 6 ±5, 9 (p-value: 0, 42). CPET revealed improvement in cardiopulmonary resilience within the group of patients that had experienced a clinical improvement whereas patients that were lacking clinical improvement did not show improved CPET parameters. Moreover In these patients we observed signs of a fixed pulmonary hypertension as by increased Arterio-alveolar gradients (Aa-gradient) and dead space ventilation (VE_VCO2-Slope) with TMVR having no effect on both parameters. Furthermore when performing a ROC-curve for the VE-VCO2-slope we were able to identify a cut-off of 37 ±4, 2 as a predictive that correlated with beneficial functional status
Conclusion:
In patients undergoing TMVR CPET proves to be robust and reliable when examining patients for possible clinical benefit of TMVR. Furthermore we were able to identify in this study a VE_VCO2_Slope of below 37, 5 being predictive of improvement of clinical functional status. No changes in dead space ventilation or Alveolar-arterial gradient were observed, both being indicative of fixed pulmonary hypertension. A decline of RV-function predicted worsening of clinical functional status
Figure 1: ROC (Receiver Operating Characteristics) curve of the VE/VCO2 Slope before MitraClip procedure at the Department of cardiology at the University of Ulm during the time period of 11/2016 until 05/2018 (AUC=Area under the curve; P=level of
significance;
Figure 2 right ventricular global longitudinal strain (RV_-GLS) with no clinical improvement (left) vs. with clinical improvement (right)
Figure 3 global longitudinal strain of the left ventricle before and after MitraClip®-procedure
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