MedicalResearch: What is the background for this study? What are the main findings?
Prof. Bosmans : Transcatheter aortic valve replacement (TAVR) has become standard of care for patients who cannot undergo surgery. With this, it is important to ensure that the risks associated with TAVR be fully understood, and if possible prevented. Even at this stage of the adoption of TAVR, large trials continue to provide information to the clinician about how to select the right patients to ensure the best possible outcomes. The ADVANCE Study is a prospective, multicenter study that evaluated the use of TAVR in 1015 patients at 44 experienced TAVR centers, which was designed to reflect routine clinical practice.
We know that the risk of serious adverse events, such as stroke or transient ischemic attack (TIA), in post-TAVR patients can vary based on the timing before and after the procedure. A patient’s baseline demographics and medical history can affect their risk of procedure-related events as well as long-term outcomes. The manipulations required crossing the aortic valve and appropriately positioning any type of TAV has been thought to be related to procedural stroke events. Therefore, we performed a multivariable analysis looking for predictors of stroke – or stroke and TIA at 3 unique time periods (periprocedural, early and late) following TAVR.
The most striking result from our analyses was that we were not able to identify any predictors of periprocedural (either during the procedure or on the day after) stroke, illustrating this very multifactorial etiology. We were able to show that being female, experiencing acute kidney injury or a major vascular complication positively predicted stroke during the early (2-30 days post procedure) time period. When we combined the outcome of stroke or TIA, we found that a history of prior atrial fibrillation (AF) was also a predictor. The only late predictor (day 31-730 post-procedure) of stroke was a history of coronary artery bypass grafting, which could reflect the patients’ risk of vascular disease.
MedicalResearch: What should clinicians and patients take away from your report?
Prof. Bosmans : We identified predictors of stroke, or stroke or TIA that can aid the clinician in their screening and assessment of patients with symptomatic aortic stenosis that may benefit from TAVR. Early predictors included both medical history and procedural outcomes as predictors. It is common knowledge that the presence of Atrial Fibrillation is associated with increased stroke risk; therefore this outcome only supports common clinical practice. The procedural predictors can be managed by optimizing renal status and ensuring that vascular access is well managed, or by using newer, lower profile TAV systems. Since approximately 40% of patients treated with TAVR had a history of CABG, additional testing could be performed to ensure the patients cerebrovascular status is optimal for the procedure.
MedicalResearch: What recommendations do you have for future research as a result of this study?
Prof. Bosmans : Our results are based on TAVR procedures performed at experienced sites, as each center was required to have performed at least 40 procedures before being allowed to participate in the study. What could be interesting would be to apply a similar predictor model, with the different inputs for the different time periods, to other studies of similar patients based on risk profiles, and without the limitation of the experience requirement.
Our study suggests that a history of Atrial Fibrillation may be an important risk factor for neurological events (stroke/TIA) early after TAVR. These results strongly suggest that, in order to reduce neurological complications after TAVR, anticoagulation therapy should be started immediately after diagnosis of the AF episode and continued for several months. No clear guidelines actually exist on anticoagulation therapy following short episodes of postoperative AF. However, patients undergoing TAVR are at high risk for thromboembolism in case of atrial arrhythmia and a more aggressive antithrombotic treatment should probably be implemented in these cases. Although dual antiplatelet therapy with aspirin and clopidogrel has been empirically recommended following TAVR, future randomized studies will have to evaluate the more appropriate antithrombotic treatment following these procedures and the potential role for systematic anticoagulant therapy either with warfarin or direct thrombin inhibitors in this setting.
Bosmans J, Bleiziffer S, Gerckens U, et al. The Incidence and Predictors of Early- and Mid-Term Clinically Relevant Neurological Events After Transcatheter Aortic Valve Replacement in Real-World Patients. J Am Coll Cardiol. 2015;66(3):209-217. doi:10.1016/j.jacc.2015.05.025.
Prof. Johan Bosmans (2015). Atrial Fibrillation Increases Risk of Stroke After TAVR