By Jeffrey Zimmet, MD, PhD
Associate Professor of Medicine, University of California, San Francisco; Director, Cardiac Catheterization Laboratory, San Francisco VA Medical Center
In this randomized controlled trial of patients with atrial fibrillation undergoing transcatheter aortic valve replacement (TAVR), concomitant left atrial appendage occlusion at the time of TAVR was noninferior to TAVR plus medical therapy for a combined endpoint of death, stroke, and major bleeding at two years.
Kapadia SR, Krishnaswamy A, Whisenant B, et al. Concomitant left atrial appendage occlusion and transcatheter aortic valve replacement among patients with atrial fibrillation. Circulation 2024;149:734-743.
Atrial fibrillation is common among patients undergoing transcatheter aortic valve replacement (TAVR) and is associated with increased morbidity and bleeding in this population. Left atrial appendage occlusion (LAAO) via a transcatheter device is approved as an alternative to anticoagulation in selected patients with atrial fibrillation. Patients with aortic stenosis undergoing TAVR are an understudied population regarding the safety and efficacy of LAAO. The concept of performing TAVR and LAAO as a combined procedure has not been studied previously.
The WATCH-TAVR trial enrolled 349 patients with severe AS and atrial fibrillation (average age 81 years; 38.7% women) from 34 North American sites. Subjects were randomized 1:1 to undergo either standard TAVR or to have a combined procedure with TAVR and LAAO performed with the Watchman 2.5 device. Patients assigned to the TAVR + LAAO arm were treated with anticoagulation plus aspirin for the first six weeks, followed by dual antiplatelet therapy (DAPT) out to six months, as per the standard Watchman protocol at that time. Patients in the TAVR-only group were medically treated at the discretion of the treating physician. The study was investigator-initiated and -designed, and was funded by Boston Scientific (the manufacturer of Watchman).
Because most LAAO procedures are performed with transesophageal echocardiogram (TEE), general anesthesia was more common in the combined procedure group. The combined procedures took an average of 43 minutes longer and used a greater volume of contrast. A majority of patients were treated as assigned. However, a total of 15 patients in the TAVR + LAAO group did not receive a Watchman device, either because of thrombus on the day of the procedure (six patients), structural incompatibility of the appendage (seven patients), technical challenges (one patient), or the amount of contrast used in a patient with kidney disease (one patient). Four patients in the LAAO group developed moderate or large pericardial effusions — a known complication of that procedure — for which three patients required pericardiocentesis.
The primary endpoint was a composite of all-cause death, stroke, or major bleeding within two years of the procedure and was not significantly different between the two groups. The primary endpoint occurred in 60 patients (33.9%) randomized to TAVR + LAAO compared with 64 patients (37.2%) randomized to TAVR alone. The individual components also were not significantly different. Although there appeared to be an early hazard to LAAO regarding bleeding, the difference narrowed over time and was not significant at two years.
Arterial or venous thrombosis or embolism was more frequent in the combined procedure group compared with the TAVR-only group (9% vs. 1.7%; hazard ratio, 5.03; 95% confidence interval, 1.47-17.26). The authors concluded that a combined procedure with TAVR + LAAO is noninferior to TAVR plus medical therapy in patients with severe AS and atrial fibrillation. They cautioned that the increased risks and complexities of the combined procedure should be taken into account when considering this approach.
COMMENTARY
WATCH-TAVR is an interesting trial that addresses several open questions in cardiology. Older patients with severe AS undergoing TAVR have not been studied previously in significant numbers regarding the option of LAAO. In this regard, it already has supplied some valuable insight. The question of whether two indicated procedures can be done safely as a combined procedure is one that comes up frequently in interventional cardiology. In the TAVR realm, the question of combined percutaneous coronary intervention and TAVR has come up many times, with some studies suggesting higher morbidity with combined procedures. Most centers continue to separate TAVR and coronary intervention.
The combination of TAVR with LAAO is, in many ways, a less obvious marriage. Although there is a movement afoot to perform LAAO with intracardiac echocardiography, a majority of these cases still are done with general anesthesia and TEE, as was done in this trial. TAVR, on the other hand, has progressed to a minimalist procedure with moderate sedation and transthoracic echocardiogram in most patients. The fact that the investigators here were able to demonstrate the relative safety of a combined procedure with a very modest increase in procedure time and contrast use is remarkable and is a testament to the skill of the operators.
Some observers were expecting a “win” for TAVR + LAAO as compared to TAVR with oral anticoagulation, based on the higher bleeding risk of this population of patients. Superiority of outcome is not what was seen here, however. In fact, the increased complexity and small but significant increased hazards of pericardial tamponade and venous thromboembolism should give us pause when considering this approach. For patients with AF and AS who already are being considered for both procedures, this trial shows that combining the two is not unreasonable and may save the patient from an additional procedure, and also save on procedure resources. However, this should not be seen as a marketing opportunity or as license to newly consider LAAO in all patients with AF referred for TAVR — which is approximately one-third of all TAVR patients.
More recent advances in LAAO device design and anticoagulation regimens are discussed in the paper as potentially changing the balance of risks in the future; however, this is hypothesis-generating only and should not change our take on this result. For a majority of patients with AS and AF, the potential risks and benefits of LAAO should be considered separately from those of TAVR for the time being.
