Percutaneous Mitral Valve Repair for Secondary Mitral Regurgitation: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to investigate whether percutaneous mitral valve repair (PMVr) using MitraClip was more effective than surgery or medical therapy for long-term morbidity and mortality. We searched MEDLINE, EMBASE, and CENTRAL (Cochrane Library) databases to identify relevant studies that recruited adult patients with functional or secondary mitral valve regurgitation who underwent PMVr with MitraClip implantation using appropriate search terms and Boolean operators. The odds ratios (ORs) were pooled using the random-effects model. A total of 14 studies recruiting 2,593 patients were included. Within 12 months of follow-up, patients who underwent PMVr did not maintain mitral valve regurgitation grade 2+ (OR 0.22, 95% confidence interval [CI] 0.12 to 0.41, p <0.0001, I2 = 0.0%, p = 0.52) or symptom-free heart failure (OR 0.47, 95% CI 0.29 to 0.77, p = 0.0028, I2 = 0.0%, p = 0.66) compared with their surgical counterparts. Patients were more likely to be rehospitalized for heart failure (OR 2.79, 95% CI 1.54 to 5.05, p = 0.0007, I2 = 0.0%, p = 0.51). However, there was no difference between the groups in terms of all-cause or cardiovascular mortality. Whereas, in comparison with medical therapy, PMVr significantly reduced all-cause mortality at 12 and ≥24 months of follow-up (OR 0.41, 95% CI 0.24, 0.69, p = 0.0009, I2 = 32%, p = 0.23 and OR 0.55, 95% CI 0.40, 0.75, p = 0.0002, I2 = 0.0%, p = 0.45, respectively). In conclusion, there was no difference in all-cause death at 12 or 24 months of follow-up between PMVr and the surgical approach, but the durability of valvular repair was inferior with PMVr. In comparison with medical therapy, there was a significant reduction in mortality with PMVr.

Computational Modeling of the Subject-Specific Effects of Annuloplasty Ring Sizing on the Mitral Valve to Repair Functional Mitral Regurgitation

Surgical repair of functional mitral regurgitation (FMR) that occurs in nearly 60% of heart failure (HF) patients is currently performed with undersizing mitral annuloplasty (UMA), which lacks short- and long-term durability. Heterogeneity in valve geometry makes tailoring this repair to each patient challenging, and predictive models that can help with planning this surgery are lacking. In this study, we present a 3D echo-derived computational model, to enable subject-specific, pre-surgical planning of the repair. Three computational models of the mitral valve were created from 3D echo data obtained in three pigs with HF and FMR. An annuloplasty ring model in seven sizes was created, each ring was deployed, and post-repair valve closure was simulated. The results indicate that large annuloplasty rings (> 32 mm) were not effective in eliminating regurgitant gaps nor in restoring leaflet coaptation or reducing leaflet stresses and chordal tension. Smaller rings (≤ 32 mm) restored better systolic valve closure in all investigated cases,but excessive valve tethering and restricted motion of the leaflets were still present. This computational study demonstrates that for effective correction of FMR, the extent of annular reduction differs between subjects, and overly reducing the annulus has deleterious effects on the valve.

Prognostic impact of functional mitral regurgitation prior to left ventricular assist device implantation

BACKGROUND

Functional mitral regurgitation (FMR) is a common finding of advanced heart failure with detrimental effects. The prognostic impact of uncorrected FMR prior to left ventricular assist device (LVAD) implantation remains controversial.

METHODS

Between 2016 and 2019 77 patients underwent continuous-flow LVAD implantation at our institution. 34 patients showed FMR ≥ 2 (MR-group), whereas 43 patients showed FMR < 2 (Control-group). Data was retrospectively analyzed. Primary composite endpoint comprised freedom from death, stroke, pump-thrombosis, major bleeding and right heart failure (RHF) after 1 year.

RESULTS

Baseline characteristics, including the severity of left and right ventricular dysfunction, and periprocedural results were comparable. The overall survival during a mean follow up of 24.9 months was 55.9% in the MR-group versus 58.1% in the Control-group (p = 0.963), whereas 1-year event-free survival was 35.3% in the MR-group compared to 44.2% in the Control-group (p = 0.404). RHF within the first postoperative year occurred more frequently in the MR-group (35.3% vs. 11.6%; p = 0.017). Furthermore, RV function was significantly reduced in comparison to baseline values in the MR-group. 12 months after surgery, 74% of patients in the MR-group were classified as NYHA III in comparison to 24% of patients in the Control-group (p < 0.001).

CONCLUSIONS

Preoperative uncorrected FMR prior to LVAD implantation did not affect overall survival, nevertheless it was associated with an impaired RV function and increased incidence of right heart failure during follow-up. Furthermore, preoperative FMR ≥ 2 was associated with persistent symptoms of heart failure.

Reduction of tethering distance by papillary muscle tugging approximation with mitral valve replacement for non-ischemic functional mitral regurgitation induces left ventricular reverse remodeling

BACKGROUND

Functional mitral regurgitation (FMR) is caused by left ventricular (LV) remodeling and subsequent tethering of the mitral valve (MV). If LV remodeling is irreversibly advanced, it could not be attenuated by the MV procedure alone, although the additional subvalvular procedure could induce LV reverse remodeling by forcibly reducing MV tethering. This study aimed to assess the anti-tethering effect of papillary muscle tugging approximation (PMTA) on LV reverse remodeling after mitral valve replacement (MVR) for non-ischemic FMR.

METHODS

The study subjects were 19 patients who underwent MVR with and without PMTA [MVR + PMTA (n = 11) and MVR alone (n = 8), respectively] for non-ischemic FMR. The tethering distance (TD) and LV end-systolic volume (ESV) at the preoperative, postoperative, and follow-up periods were assessed in terms of their correlation and time-dependent changes. The intra-LV energy efficiency was also evaluated through vector flow mapping analysis.

RESULTS

TD and ESV were comparable between both procedures preoperatively and did not change after MVR alone. In MVR + PMTA, however, a significant decrease was identified in TD and ESV at the early postoperative and follow-up periods, respectively [TD = 48, 30, and 31 mm (p < 0.001) and ESV = 159, 133, and 82 mL (p < 0.001) at the preoperative, postoperative, and follow-up periods, respectively]. Finally, at follow-up, the extent of change from the preoperative value in ESV significantly correlated with that in TD (ρ = 0.81, p < 0.001 for overall; ρ = 0.93, p < 0.001 for MVR + PMTA; ρ = 0.86, p = 0.011 for MVR alone). The ratio of TD to ESV was also significantly correlated with systolic energy loss to LV stroke work after MVR + PMTA (ρ = 0.81, p = 0.015).

CONCLUSIONS

PMTA for non-ischemic FMR could induce LV reverse remodeling depending on the extent of postoperative TD reduction. A smaller TD to ESV was associated with a higher intra-LV energy efficiency after PMTA + MVR.

Surgery for heart failure: Treatment options and implications

Heart failure is considered one of the leading causes of death worldwide. Over the years, etiological risk factors, diagnostic criteria, and classifications have been revised to create guide management needed to alleviate the global health burden caused by heart failure. Pharmacological treatments have progressed over time but are insufficient in reducing mortality. This leads to many patients developing advanced heart failure who will require surgical intervention often in the form of the gold standard, a heart transplant. However, the number of patients requiring a transplant far exceeds the number of donors. Other surgical inventions have been utilized, yet the rate of patients being diagnosed with heart failure is still increasing. Future developments in the surgical field of heart failure include the 77SyncCardia and atrial shunting but long-term clinical trials involving larger cohorts of patients have not yet taken place to view how effective these approaches can be.