Incidence, clinical correlates, timing, and consequences of acute thrombus formation in patients undergoing the MitraClip procedure

Strategy to optimize PeriproCeduraL AnticOagulation in structural transseptal interventions: Design and rationale of the STOP CLOT trial

BACKGROUND

Both transcatheter edge-to-edge repair (TEER) of mitral regurgitation or left atrial appendage closure (LAAC) require periprocedural anticoagulation with unfractionated heparin (UFH) that is administered either before or immediately after transseptal puncture (TSP). The optimal timing of UFH administration (before or after TSP) is unknown. The Strategy To Optimize PeriproCeduraL AnticOagulation in Structural Transseptal Interventions trial (STOP CLOT Trial) was designed to determine if early anticoagulation is effective in reducing ischemic complications without increasing the risk of periprocedural bleeding.

METHODS

The STOP CLOT trial is a multicenter, prospective, double-blind, placebo-controlled, randomized trial. A total of 410 patients scheduled for TEER or LAAC will be randomized 1:1 either early UFH administration (iv. bolus of 100 units/kg UFH or placebo, given after obtaining femoral vein access and at least 5 minutes prior to the start of the TSP) or late UFH administration (iv. bolus of 100 units/kg UFH or placebo given immediately after TSP). Prespecified preliminary statistical analysis will be performed after complete follow-up of the first 196 randomized subjects. To ensure blinding, a study nurse responsible for randomization and UFH/placebo preparation is not involved in the care of the patients enrolled into the study. The primary study endpoint is a composite of (1) major adverse cardiac and cerebrovascular events (death, stroke, TIA, myocardial infarction, or peripheral embolization) within 30 days post-procedure, (2) intraprocedural fresh thrombus formation in the right or left atrium as assessed with periprocedural transesophageal echocardiography, or (3) occurrence of new ischemic lesions (diameter ≥4 mm) on brain magnetic resonance imaging performed 2 to 5 days after the procedure. The safety endpoint is the occurrence of moderate or severe bleeding complications during the index hospitalization.

CONCLUSIONS

Protocols of periprocedural anticoagulation administration during structural interventions have never been tested in a randomized clinical trial. The Stop Clot trial may help reach consensus on the optimal timing of initiation of periprocedural anticoagulation.

CLINICAL TRIALS REGISTRATION NUMBER

The study protocol is registered at ClinicalTrials.gov, identifier NCT05305612.

Acute Device-Related Thrombus Elimination During Transcatheter Edge-to-Edge Repair Via Vacuum Catheter Aspiration

We describe a rare complication of intraprocedural spontaneous thrombus formation on a transcatheter edge-to-edge repair (MitraClip; Abbott Laboratories) device in a hypercoagulable yet adequately anticoagulated patient. We also outline the novel use of a vacuum (Penumbra) aspiration system, which resulted in rapid and effective thrombus elimination.

Management of Right Atrial Thrombus During MitraClip Implantation: A Case Report and Review of Literature

Transcatheter mitral valve repair (TMVR) is a relatively novel approach for treatment of symptomatic severe mitral regurgitation. Intra procedural thrombus formation is a rare but potential complication. Herein, we describe a case of large right atrial thrombus formation after transseptal puncture, that was successfully managed using aspiration thrombectomy.

Complications Following MitraClip Implantation

Purpose of Review

To provide a detailed overview of complications associated with MitraClip therapy and its development over time with the aim to alert physicians for early recognition of complications and to offer treatment strategies for each complication, if possible.

Recent Findings

The MitraClip system (MC) is the leading transcatheter technique to treat mitral regurgitation (MR) and has been established as a safe procedure with very low adverse event rates compared to mitral surgery at intermediate to high risk or in secondary MR. Lately, the fourth MC generation has been launched with novel technical features to facilitate device handling, decrease complication rates, and allow the treatment of even complex lesions.

Summary

Although the complication rate is low, adverse events are associated with increased morbidity and mortality. The most common complications are bleeding, acute kidney failure, procedure-induced mitral stenosis, and an iatrogenic atrial septal defect with unknown clinical impact.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11886-021-01553-9.