About different localization of hypoattenuated lesions following transcatheter aortic valve replacement

BACKGROUND

Subclinical leaflet thrombosis is diagnosed using multidetector computed tomography (MDCT) and is characterised by a meniscal-shaped hypoattenuated lesion of one or more leaflets. Transcatheter aortic self-expandable valves are commonly manufactured with pliable pericardium over a nitinol frame that forms leaflet and extra-leaflet components such as the valve skirt. Little is known about extra-leaflet hypoattenuated lesion localisation, including that at the anatomical sinus level. Thus, the main aim of this study was to describe leaflet and extra-leaflet (anatomic sinus and subvalvular level) hypoattenuated lesions following transcatheter aortic valve replacement with a self-expandable prosthesis. As a secondary aim, we sought to investigate predictors of hypoattenuated lesions.

METHODS

Fifty patients underwent MDCT at the follow-up.

RESULTS

At a follow-up of 12 months, hypoattenuated leaflet lesions with mild to severe restricted movement were detected in eight individuals (16%), anatomic sinus lesions were identified in nine patients (18%), with higher prevalence in the non-coronary sinus (16%), and subvalvular lesions with variable extension toward the valve inflow were diagnosed in eight patients (16%). In 4 patients (8%) the anatomic sinus thrombus was 'in overlap' with leaflet thrombus; in 3 patients (6%) was in continuity with subvalvular frame thrombus. Bicuspid valve was the only independent predictor associated with hypoattenuated lesions (adj OR 8.25 (95% CI: 1.38, 49.21), p = 0.02)).

CONCLUSIONS

This study demonstrated that hypoattenuated lesions could be identified not only at the leaflet but also at the subvalvular and anatomic sinus levels. The clinical relevance of such lesions remains unclear.

Evaluation of the anatomic sinus after transcatheter aortic valve replacement

BACKGROUND

Following transcatheter aortic valve replacement (TAVI), the newly formed 'anatomic sinus'. may contribute to the formation of subclinical leaflet thrombosis (SLT).The evaluation of root geometry after TAVI is generally performed using multi-detector computed tomography (MDCT), and the role of transthoracic echocardiography (2D TTE) requires further validation. Thus, we aimed to test the reproducibility of 2D TTE assessment of the anatomic sinus with MDCT as a reference and its association with SLT.

METHODS

2D TTE was performed in 90 patients, and the echocardiograms were analyzed offline. Both sinus of Valsalva (SOV) and prosthesis diameters were assessed in the long- and short-axis parasternal views (PLAX/PSAX), and the anatomic sinus area was calculated. Inter- and intra-observer reproducibility were assessed using the interclass correlation coefficient (ICC). MDCT was performed in 50 individuals to evaluate concordance with 2D TTE and to detect SLT.

RESULTS

There was excellent correlation regarding the diameter of the SOV and the prosthesis in PLAX (ICC: 0.93 (95% CI: 0.76,0.97); ICC: 0.80 (95% CI: 0.63,0.96)) and PSAX view (ICC: 0.90 (95% CI: 0.68,0.97); ICC: 0.88 (95% CI: 0.63,0.96)). Bland-Altman analysis of 2D TTE and MDCT anatomic sinus areas indicated a high level of agreement. SLT was detected in 8 individuals (16%); 3 patients had severe SLT at the level of 1 cusp.

CONCLUSIONS

2D TTE might play a role in the evaluation of the anatomic sinus after TAVI. The importance of this space and its effects on the SLT remain uncertain.

Self-Expandable Prosthesis Valve Adaptation: Non-Uniform Expansion and Stent Frame Decoupling

The incidence of non-uniform expansion in the context of the self-expandable transcatheter heart valve (THV) is little investigated, along with stent-frame decoupling, which is a form of stent adaptation, in which the lower part of the THV stent conforms to both the ellipticity of the left ventricle outflow tract and the native annulus while maintaining the higher part of the valve more circular. We analyzed post-implant multi-detector computed tomography scans in 50 patients. Prosthesis non-uniform expansion was assessed by computing the prosthesis eccentricity on 6 prespecified levels: (1) frame inflow, (2) native annulus, (3) leaflet inflow, (4) prosthesis waist, (5) leaflet outflow, and (6) frame outflow. Stent-frame decoupling was assessed by comparing the mean eccentricity on 6 different prosthesis levels. Implantation depth, leaflet expansion and alignment, and residual anatomic sinus area ratios were also calculated. Subclinical leaflet thrombosis was defined as hypoattenuated lesion of a meniscal shape. At a 12-month follow-up, non-uniform expansion was consistently detected at each valvular level. Highest eccentricity was measured at the native annulus level (eccentricity: 0.54 ±  0.12), while the lowest index at the frame outflow level (0.23 ± 0.11). Similar results were observed in the subgroup analyses of sizes 23, 26, 29, and 34. Eccentricity significantly decreased from the annulus level to the prosthesis frame outflow (p <0.001). Notably, the incidence of mild-to-severe subclinical leaflet thrombosis was relevant (16%). In conclusion, prosthesis non-uniform expansion and stent frame decoupling frequently occur after self-expandable THV replacement. The clinical and hemodynamic implications remain uncertain.

Subclinical Leaflet Thrombosis Following Surgical and Transcatheter Aortic Valve Replacement: A Meta-Analysis

Subclinical leaflets valve thrombosis (SLT) is a recently identified phenomenon with multidetector computer tomography after tissue aortic valve replacement. Whether SLT is more frequent after transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR) is currently not known. Thus, the aim of this pairwise meta-analysis was to investigate the incidence of SLT after both TAVR and SAVR, the association with anticoagulation therapy, and the risk for neurological events. We searched PubMed, Google Scholar, and Ovid MEDLINE/Embase (January 02, 2023, last update) (PROSPERO registration: CRD42022383295). Statistical analysis was performed according to a prespecified statistical analysis plan. Time-to-event outcomes were summarized as incidence rate ratios (IRR). Pooled estimates were calculated using inverse variance method and random effect model. Overall, 2 registries, 2 randomized trials, and 1 observational study (1,593 patients) were included in this meta-analysis. There was a statistically significant difference in the incidence rate at follow-up of SLT between patients who underwent TAVR and SAVR (IRR 2.07, 95% confidence interval [CI]: [1.06; 4.03], I2 79%, 95% CI: [44; 92], p = 0.03). Oral anticoagulation therapy was associated with a reduced incidence of SLT (IRR 7.51, 95% CI: [3.24; 17.37], I2 62%, 95% CI: [0; 87], p <0.001). However, the incidence of later neurological events did not differ between patients with or without SLT (IRR 1.05, 95% CI: [0.32; 3.47], p = 0.93). In conclusion, SLT was more frequently detected after TAVR than SAVR. However, it was not associated with an increased risk for neurological events. Oral anticoagulation therapy seemed to reduce the incidence of SLT.