Early results of the ongoing Polish Registry of Valve Thrombosis after Transcatheter Aortic Valve Implantation (ZAK‑POLTAVI)

Bioprosthetic leaflet thrombosis and reduced leaflet motion after transcatheter aortic valve replacement: A systematic review and meta-analysis

BACKGROUND

Leaflet thrombosis and reduced leaflet motion have become a concern with the expanding use of transcatheter aortic valve replacement in lower-risk patients.

AIMS

To assess the proportions, predictors and clinical impact of leaflet thrombosis and reduced leaflet motion after transcatheter aortic valve replacement.

METHODS

We performed a meta-analysis of studies assessing the proportions of and/or clinical outcomes according to the presence of leaflet thrombosis after transcatheter aortic valve replacement identified with computed tomography and/or echocardiography.

RESULTS

Fifty-three studies, representing 25,258 patients undergoing transcatheter aortic valve replacement, were considered. The proportion of leaflet thrombosis was 5.2% overall, and was higher in computed tomography versus echocardiography (16.4% vs. 1.1%, respectively); reduced leaflet motion was identified in 11% of patients with four-dimensional computed tomography. Intra-annular bioprostheses were associated with a higher proportion of leaflet thrombosis, whereas chronic oral anticoagulation was protective for leaflet thrombosis in both computed tomography and echocardiographic studies (9.7% vs. 17.5%; relative risk [RR]: 0.51, 95% confidence interval [95% CI]: 0.37-0.71 and 0.9% vs. 2.7%; RR: 0.22, 95% CI: 0.06-0.79, respectively) and for reduced leaflet motion (2.5% vs. 12.4%; RR: 0.32, 95% CI: 0.13-0.76). Leaflet thrombosis was not associated with an increased risk of death, but with a higher risk of stroke in computed tomography studies (2.8% vs. 2.4%; RR: 1.63, 95% CI: 1.05-2.55), a difference more pronounced when considering reduced leaflet motion (3.5% vs. 1.7%; RR: 2.39, 95% CI: 0.63-8.34).

CONCLUSIONS

The proportion of leaflet thrombosis is highly variable according to the screening approach, the type of valve and the use of oral anticoagulation. The occurrence of cerebral events is increased when leaflet thrombosis and/or reduced leaflet motion are diagnosed, but leaflet thrombosis has no impact on survival.

Subclinical Leaflet Thrombosis After Balloon versus Self-Expandable Transcatheter Aortic Valve Implantation

Hypoattenuated leaflet thickening (HALT) has been recognized as one of the complications after transcatheter aortic valve implantation and may promote structural valve degeneration and increase the risk of cerebrovascular events. The 2 main types of available transcatheter heart valves (THVs), the balloon-expandable (BE) and the self-expanding (SE), are interchangeably used in clinical practice despite substantial design differences. There is unclear evidence on whether these 2 different THV models are achieving similar or different rates of subclinical leaflet thrombosis/HALT. A systematic search of electronic databases was conducted to identify studies that reported the incidence of HALT between SE THVs and BE THVs. The Mantel-Haenszel method was used to calculate the 95% confidence interval and pooled risk ratio with a random-effects model. A total of 126 records were identified, of which 22 studies comprising 14,401 patients were included in our final analysis. Among 5,951 patients receiving SE THVs, 194 (3.2%) developed HALT, compared with 8,450 patients receiving BE THVs, of whom 484 (5.7%) developed HALT. There was a statistically significant decrease in the risk of developing HALT in patients receiving SE THVs compared with those receiving BE THVs (risk ratio 0.75, 95% confidence interval 0.59 to 0.95, I² 32%, p = 0.02). In conclusion, could potentially reduce the risk of HALT/subclinical leaflet thrombosis.

Subclinical Leaflet Thrombosis After Transcatheter Aortic Valve Replacement: A Meta-Analysis

This meta-analysis and systematic review was performed to evaluate the clinical relevance of subclinical leaflet thrombosis (SLT) following transcatheter aortic valve replacement. PubMed, Web of Science, and CENTRAL were searched for eligible randomized and nonrandomized studies until November 2020. Risk ratios (RRs) or odds ratios and 95% CIs were calculated, using a random-effects model. Overall, 25 studies were eligible for the analysis and comprised a total of 11,098 patients. The median incidence of SLT was 6% at a median follow-up of 30 days. Use of intra-annular valves was associated with 2-fold greater risk for the development of SLT compared with use of supra-annular valves. There was no difference in the risk for SLT (RR: 0.97; 95% CI: 0.72-1.29; P = 0.83) between single-antiplatelet therapy (SAPT) and dual-antiplatelet therapy (DAPT), whereas oral anticoagulation (OAC) was associated with a 58% relative risk reduction for SLT (RR: 0.42; 95% CI: 0.29-0.61; P < 0.00001) compared with SAPT and DAPT. In patients with diagnosed leaflet thrombosis at follow-up, the risk for stroke or transient ischemic attack was increased by 2.6-fold (RR: 2.56; 95% CI: 1.60-4.09; P < 0.00001) compared with patients without leaflet thrombosis. In patients diagnosed with SLT, the odds of SLT resolution increased by 99% after switch from antiplatelet agents to OAC (odds ratio: 0.01; 95% CI: 0.00-0.06; P < 0.00001). To summarize, indication-based use of OAC after transcatheter aortic valve replacement is associated with a lower risk for SLT compared with SAPT and DAPT. Switching to OAC seems to be effective for SLT resolution. As SLT increased the odds of stroke or transient ischemic attack in the included population, further studies are needed to investigate whether screening tests for SLT and appropriate antithrombotic therapy improve long-term valve functionality and clinical prognosis.