Closure of Iatrogenic Atrial Septal Defects Following Transcatheter Mitral Valve Repair - MITHRAS

Oct 15, 2020
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Author/Summarized by Author:
Dharam J. Kumbhani, MD, SM, FACC
Summary Reviewer:
Deepak L. Bhatt, MD, MPH, MBA, FACC
Trial Sponsor:
Leipzig Heart Institute and Occlutech
Date Presented:
10/15/2020
Date Published:
10/15/2020
Date Updated:
10/15/2020
Original Posted Date:
10/15/2020
References

Contribution To Literature:

In the MITHRAS trial, routine closure of iatrogenic ASDs post-TMVr does not result in improved 6-minute walk distance or an improvement in mortality/HF hospitalization compared with conservative management, despite a normalization in Qp:Qs (baseline Qp:Qs ≥1.3; mean 1.5).

Description:

The goal of the trial was to assess the efficacy of routine closure of persistent iatrogenic atrial septal defect (ASD) with relevant left-to-right shunting and a Qp:Qs of ≥1.3 among patients who had undergone trans-septal transcatheter mitral valve repair (TMVr).

Study Design

Patients with persistent iatrogenic ASD and relevant left-to-right shunting (Qp:QS ≥1.3) 1 month post-TMVr were randomized in an open-label 1:1 fashion to either percutaneous ASD closure (n = 40) or control (n = 40). Closure was performed with Figulla Flex II, Occlutech, Jena, Germany.

  • Total number of enrollees: 80
  • Duration of follow-up: 1 year
  • Mean patient age: 77 years
  • Percentage female: 39%

Inclusion criteria:

  • Left-to-right shunting with Qp:QS ≥1.3

Exclusion criteria:

  • Presence of interatrial shunt prior to TMVr
  • No TMVr success
  • Additional valvular heart disease planned for surgery or intervention
  • Malignancy with expected survival <12 months
  • Anatomic considerations precluding transcatheter ASD closure

Other salient features/characteristics:

  • EuroSCORE II: 5.2%
  • Residual mitral regurgitation grade 0/1: 78%, 2+: 20%
  • Residual tricuspid regurgitation grade: 0/1: 52%, 2: 34%
  • Left ventricular ejection fraction: 38%

Principal Findings:

The primary endpoint, change in 6-minute walk distance at 5 months, for ASD closure vs. conservative management, was 5 vs. -1 m (p = 0.76).

Secondary endpoints for ASD closure vs. conservative management:

  • Change in N-terminal pro-B-type natriuretic peptide from baseline: -846 vs. -279 pg/ml (p = 0.44)
  • Change in Qp:Qs from baseline: -0.5 vs. -0.2 (p = 0.02)
  • Mortality or heart failure (HF) hospitalization at 1 year: 21% vs. 23% (p = 0.22)

Interpretation:

The results of this trial indicate that routine closure of iatrogenic ASDs post-TMVr does not result in improved 6-minute walk distance or an improvement in mortality/HF hospitalization compared with conservative management, despite a normalization in Qp:Qs (baseline Qp:Qs ≥1.3).

This is a helpful trial despite its small sample size since it addresses a commonly encountered clinical scenario. ASD closure may still be warranted for large defects/tears caused by trans-septal access during TMVr. It is also possible that a persistent shunt may have some beneficial effects in patients with significant residual mitral regurgitation by allowing for left atrial decompression into the right side.

References:

Lurz P, Unterhuber M, Rommel KP, et al., Closure of Iatrogenic Atrial Septal Defect Following Transcatheter Mitral Valve Repair: The Randomized MITHRAS Trial. Circulation 2020;Oct 15:[Epub ahead of print].

Presented by Dr. Philipp Lurz at the Transcatheter Cardiovascular Therapeutics Virtual Meeting (TCT Connect), October 15, 2020.

Clinical Topics: Cardiac Surgery, Congenital Heart Disease and Pediatric Cardiology, Diabetes and Cardiometabolic Disease, Geriatric Cardiology, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Prevention, Valvular Heart Disease, Cardiac Surgery and CHD and Pediatrics, Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Congenital Heart Disease, CHD and Pediatrics and Interventions, CHD and Pediatrics and Prevention, Acute Heart Failure, Heart Failure and Cardiac Biomarkers, Interventions and Structural Heart Disease, Exercise, Mitral Regurgitation

Keywords: Cardiac Surgical Procedures, Geriatrics, Heart Failure, Heart Septal Defects, Atrial, Heart Valve Diseases, Mitral Valve Insufficiency, Hospital Mortality, Iatrogenic Disease, Natriuretic Peptide, Brain, TCT20, Transcatheter Cardiovascular Therapeutics, Tricuspid Valve Insufficiency, Walking


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