Residual mitral regurgitation impact on outcomes after mitraclip therapy: five-year follow-up from the GRASP registry

Funding Acknowledgements

Type of funding sources: None.

Background – Although percutaneous mitral valve repair is an attractive alternative treatment option for patients with severe mitral regurgitation (MR) at high surgical risk, residual MR is commonly observed after the procedure and little is known about its impact on outcomes after MitraClip therapy, expecially in patients with severe left ventricular (LV) impairment.

Purpose – The aim of this prospective, observational study was to evaluate the impact of residual MR (MR ≤1+ vs. MR >1+) on long-term outcomes of mitral valve repair with the MitraClip System in high surgical risk patients presenting with moderate-to-severe or severe MR and with severe reduction of LV ejection fraction (EF).

Methods – Patients enrolled in the prospective Getting Reduction of Mitral Insufficiency by Percutaneous Clip Implantation (GRASP) with functional MR and EF ≤30% who were eligible at almost five-year follow-up were included in the present analysis.  The primary endpoint was death at 5-year follow-up.  Also echocardiographic parameters at baseline and 5-year follow-up and rehospitalization rates were assessed.

Results – A total of 139 patients were included: 92 (66.2%) with post-procedural residual MR ≤1+ and 47 (33.8%) with residual MR > 1+ (41 patients with residual MR 2+, 5 with residual MR 3+, 1 with residual MR 4+).  Comparable clinical and echocardiographic baseline characteristics were observed between the two groups except for NYHA functional class IV and implanted pace-maker (more frequent in patients with residual MR >1+) and previous myocardial infarction (more frequent  in patients with residual MR ≤1+). At 5-year follow-up, no significant differences were reported in the primary endpoint (49.6% in patients with residual MR ≤ 1+ vs. 65.3% in patients with residual MR > 1+, p 0.203) and in cardiac death (37.8% in patients with residual MR ≤ 1+ vs. 42.6% in patients with residual MR > 1+, p 0.921). Cox regression analysis identified residual MR > 1+ as an independent predictor of re-hospitalization (HR 0.51, 95% CI 0.28-0.92, p =0.026). At 5-year follow-up,  a significant reduction in left ventricular end-systolic volume was  observed in patients with residual MR ≤ 1+.

Conclusions – At 5-year follow no significant differences in survival emerged in patients with severe  LV dysfunction undergoing MitraClip therapy regardless residual MR. Nevertheless residual MR > 1+ emerged as an indipendent predictor of re-hospitalization.

[Echocardiography in the early diagnosis of acute rejection in patients with heart transplant]

The aim of our study was to assess the sensibility and specificity of Doppler echocardiographic evaluation of left ventricular diastolic function during acute cardiac rejection. We studied 34 patients who had undergone a recent heart transplant and compared the echocardiographic results with the histologic findings. We considered the following parameters of left ventricular filling: early peak of mitral flow velocity; pressure half-time (PHT); isovolumic relaxation time (IVRT). We divided the patients into two groups according to the histologic findings: Group I (25 patients who had at least 1 episode of mild-moderate rejection), Group II (6 patients without documented rejection after at least three consecutive biopsies). Three patients with clinically evident rejection were excluded from the analysis. In Group I cardiac rejection was associated with a statistically significant decrease in IVRT (p < 0.0005), without significant changes in heart rate and in the early peak of mitral flow velocity. In Group II Doppler parameters remained unchanged. These variations were not associated with changes in echocardiographic morphologic parameters and in parameters of ventricular systolic function. IVRT and PHT returned to normal values after adequate immunosuppressive treatment. Considering variations of IVRT and PHT of at least 20%, we obtained a sensibility of 88% for isolated variations of PHT and a specificity of 93% for consensual variations of PHT and IVRT. Therefore, the assessment of the left ventricular diastolic function by Doppler echocardiography represents a safe and non-invasive method for an early detection of acute cardiac rejection.

[Percutaneous valvuloplasty in mitral stenosis]

Since May 1991 to July 1992, 83 patients (mean age 49 +/- 13 years, 17 males and 66 females) underwent percutaneous mitral valvuloplasty according to Inoue's technique. Following Wilkins' criteria echo-score was < or = 8 in 46 patients and mono-commissural calcifications were present in 8 cases. Sixteen (19%) patients had previous surgical mitral commissurotomy and 15 (18%) had previous embolic events. The indications for the procedure were given on the basis of the echo-score (ideal cases with score < or = 8). All patients but 2 were successfully treated. Two patients who developed mitral regurgitation grade 3+/4+ were referred to elective surgery. Mitral valve area increased from 1.1 +/- 0.2 to 2 +/- 0.3 cm2 (p < 0.001) and transvalvular pressure gradient fell from 16 +/- 5 to 6 +/- 3 mmHg (p < 0.001). Patients with previous surgical commissurotomy had a lower increase in mitral valve area than patients without previous surgery (p < 0.02). Patients with echo-score > 8 presented a more evident increase in mitral regurgitation than patients with good valvular anatomy, even if this difference was not significant. At 6 and 12 month follow-up respectively 2 and 1 restenosis occurred, but in 1 of these cases the residual valvular area was > 1.5 cm2. The authors conclude that in selected patients with mitral stenosis percutaneous mitral valvuloplasty seems to be an effective and safe treatment. Furthermore, immediate and middle-term results show that this technique can be performed without adjunctive risks and with satisfactory results also in cases of no ideal clinical and/or valvular conditions (echo-score > 8, previous surgical commissurotomy, history of embolism, mono-commissural calcifications).