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.

Assessment of consistency in aortic valve sizing between surgical and transcatheter aortic valve replacement.

Introduction: One of the crucial aspects of transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR) is the valve prosthesis selection. Aim: To assess the consistency of the aortic valve sizing in SAVR and TAVR by comparing the sizes of aortic prostheses selected based on the intraprocedural annulus measurements and simulation of the TAVR planning. Material and methods: The study comprised of 167 patients with aortic stenosis treated with SAVR. Simulation of the prosthesis sizing blinded to the SAVR results was performed based on the assessment of cardiac computed tomography (CCT) images. Results: Based on the CCT images, the average value of the aortic annulus diameter was 25.4 ±3.0 mm. Aortic valve calcifications were mild in 29 cases, moderate in 78 cases, and severe in 53 cases. The sizes of the valves recommended by the simulations were larger than valves surgically implanted in 98.6% of patients for self-expanding and in 91.7% of patients for balloon-expandable prostheses. The average difference for self-expanding prostheses was 6.4 mm and 4.5 mm for balloon expandable valves. Additionally, a negative correlation was observed for the difference in prosthesis size and size of the valve used by surgeons. Conclusions: There is a systematic difference between sizes of aortic prostheses used in SAVR and TAVR. Further studies are needed to evaluate if the difference in prosthesis size selection contributes to the frequency of prosthesis-patient mismatch phenomenon and burden of high postoperative mean transaortic gradient.