Methods: We performed 2-D echocardiography, Doppler echocardiography and 2-D LV strain analysis in 25 patients with severe functional MR before and after (mean 3.6±2.3 days) MC and at follow up (FU, mean 172±70 days). Patients were grouped as having strong MR reduction (MR-, MR =1, n=14) on FU or as having less MR reduction (MR+, MR>1, n=11). Repeated measures ANOVA was used to reveal changes between pre- and postinterventional parameters and parameters on FU.
Results: Baseline characteristics were well balanced between both groups (mean age 74±8 years, 40% female, 52% ischemic cardiomyopathy, 72% atrial fibrillation) as well as echocardiographic parameters (mean LV-EF 38±3%, LV end diastolic volume (EDV) 116±39 ml/m², global longitudinal strain (GLS) -9.1±4.9%, left atrial end-systolic volume index (LAESVI) 65±21 ml/m²). Two clips were implanted in 43% of MR- patients and 18% of MR+ patients (p=0.23).
No changes in LVEDV were observed in MR+ patients (pre 106 ± 33, post 107 ± 28, FU 111 ± 24ml/m², p=0.77) while MR- patients showed a lower LVEDV on FU (pre 123 ± 43, post 119 ± 46, FU 111 ± 46ml/m², p=0.01 pre vs FU). LVEF and GLS dropped postinterventional in MR-, but recovered to previous level on FU (LVEF pre 40±15, post 31±12, FU 38±13%, p=0.001 pre vs post and post vs FU; GLS pre -9.1±5.6, post -7.3±5.1, FU -10.0±5.4, p=0.001 pre vs post and post vs FU). In MR+ patients LVEF remained unchanged postinterventional but showed a significant drop on FU as compared to preinterventional (pre 37±11, post 36±10, FU 32±7%, p=0.02 pre vs FU) and GLS dropped immediately postinterventional with further deterioration on FU (pre -9.1±4.1, post -8.1±3.7, FU -7.9±2.7, p=0.04 pre vs FU). No correlation between the number of implanted clips and changes in GLS or LVEF could be found (p=n.s.).
Conclusion: In patients with functional MR and moderately to severely depressed LV function treated with percutaneous mitral valve repair, MR reduction to grade =1 leads to acute dropping in LV function -most likely due to preload reduction- with recuperation on follow up while patients without significant MR reduction experience further decline in LV function on follow up.