Ryo Yanagisawa (Department of Cardiology, Keio University School of Medicine, Tokyo, Japan) and colleagues report in JACC: Cardiovascular Imaging that hypoattenuated leaflet thickening after transcatheter aortic valve implantation (TAVI) is “not rare but usually subclinical”. According to study author Kentaro Hayashida (Department of Cardiology, Keio University School of Medicine, Tokyo, Japan), because of a lack of data, the optimum solution for managing leaflet thickening is still unknown.
In your study, 14.3% of patients developed hypoattenuated leaflet thickening by one year. Do you think this is representative of the incidence in clinical practice?
This result is from an Asian patient cohort who underwent TAVI with the Sapien XT valve (Edwards Lifesciences), so I am not sure if it is representative of what occurs overall in clinical practice. However, our study does provide—at least in part—some insights into leaflet thickening at long-term follow-up.
Which factors were associated hypoattenuated leaflet thickening?
We found that it was associated with male sex, large sinus of Valsalva and large bioprostheses.
Your study is one of the few to demonstrate systematic and prospective one-year follow-up of multidetector computed tomography MDCT) scanning to detect hypoattenuated leaflet thickening. Do you think MDCT should be used in routine clinical practice to detect leaflet thickening?
No. Most patients in this cohort (ie. undergoing TAVI) will have reduced renal function, so would be at risk of renal injury if they underwent routine MDCT scanning. Additionally, MDCT is costly. Therefore, in our study, we propose that D-dimer could be used as a marker to detect leaflet thickening in combination with transthoracic echocardiogram or transoesophageal echocardiography findings. However, MDCT could be performed in selected patients.
You did not find, unlike previous studies, that leaflet thickening was associated with stroke or other thrombotic events. Why do you think that this was?
Our study was a prospective and systematic MDCT study and was not driven by symptoms. Furthermore, the small patient cohort is a limitation (70 patients from a single-centre registry). These factors could explain the discrepancy between our findings and those of the preceding reports.
How would you manage a patient with leaflet thickening?
The optimal management remains controversial. Most previous publications have demonstrated that administration of warfarin resolves leaflet thickening. But in our study, none of the patients with leaflet thickening were treated with additional anticoagulation because of the associated inherent risk of bleeding in older patients (the mean age of the patient cohort was 85 years). The solution for managing leaflet thickening should be evaluated in a larger study.
When would you consider using anticoagulation in the presence of leaflet thickening?
If a patient developed symptoms related to the leaflet thickening (ie. an increase of pressure gradient), then I would consider prescribing additional anticoagulation. However in terms of enhancing the long-term durability of leaflets, the best strategy for achieving that is still unresolved—ie., we do not yet know if using anticoagulation will increase valve durability.
Do you think leaflet thickening, and its possible effect on valve durability, could be a barrier to using TAVI in lower risk patients?
We can also detect hypoattenuated leaflet thickening in surgical bioprostheses; therefore, I am not sure if it will be a barrier. But, we should be careful to proceed to low-risk patients, especially young patients, before this problem is resolved.
What further studies are needed in this area?
The optimal antithrombotic regimen after TAVI should be established. For example, should we use single antiplatelet therapy, dual antiplatelet therapy, warfarin, or direct oral anticoagulation? We also need to understand the impact of hypoattenuated leaflet thickening on valve durability and systemic embolism during longer-term follow-up. Furthermore, if a patient does have evidence of leaflet thickening, how should we manage it? Should we use anticoagulation or just carefully watch the patient? There is a lot to be solved!