Subclinical Leaflet Thrombosis Research Articles

E-44 | Clinical Perspectives on Valvular and Subclinical Leaflet Thrombosis after Transcatheter Aortic Valve Replacement: Insights from the US FDA MAUDE Database

E-44 | Clinical Perspectives on Valvular and Subclinical Leaflet Thrombosis after Transcatheter Aortic Valve Replacement: Insights from the US FDA MAUDE Database

Three-dimensional analysis of subclinical leaflet thrombosis following transcatheter aortic valve replacement.

Three-dimensional analysis of subclinical leaflet thrombosis following transcatheter aortic valve replacement.

Effect of Sinotubular Junction Size on TAVR Leaflet Thrombosis: A Fluid-Structure Interaction Analysis.

TAVR has emerged as a standard approach for treating severe aortic stenosis patients. However, it is associated with several clinical complications, including subclinical leaflet thrombosis characterized by Hypoattenuated Leaflet Thickening (HALT). A rigorous analysis of TAVR device thrombogenicity considering anatomical variations is essential for estimating this risk. Clinicians use the Sinotubular Junction (STJ) diameter for TAVR sizing, but there is a paucity of research on its influence on TAVR devices thrombogenicity. A Medtronic Evolut® TAVR device was deployed in three patient models with varying STJ diameters (26, 30, and 34mm) to evaluate its impact on post-deployment hemodynamics and thrombogenicity, employing a novel computational framework combining prosthesis deployment and fluid-structure interaction analysis. The 30mm STJ patient case exhibited the best hemodynamic performance: 5.94mmHg mean transvalvular pressure gradient (TPG), 2.64 cm2 mean geometric orifice area (GOA), and the lowest mean residence time (TR)-indicating a reduced thrombogenic risk; 26mm STJ exhibited a 10 % reduction in GOA and a 35% increase in mean TPG compared to the 30mm STJ; 34mm STJ depicted hemodynamics comparable to the 30mm STJ, but with a 6% increase in TR and elevated platelet stress accumulation. A smaller STJ size impairs adequate expansion of the TAVR stent, which may lead to suboptimal hemodynamic performance. Conversely, a larger STJ size marginally enhances the hemodynamic performance but increases the risk of TAVR leaflet thrombosis. Such analysis can aid pre-procedural planning and minimize the risk of TAVR leaflet thrombosis.

Periprocedural Thrombogenicity Change Is Associated With Subclinical Leaflet Thrombosis Progression in Patients Undergoing Transcatheter Aortic Valve Implantation

Periprocedural Thrombogenicity Change Is Associated With Subclinical Leaflet Thrombosis Progression in Patients Undergoing Transcatheter Aortic Valve Implantation

Abstract 12293: Subclinical Leaflet Thrombus on Transcatheter Heart Valve in Patients With Severe Aortic Stenosis and Atrial Fibrillation

Background: Subclinical leaflet thrombosis is one of transcatheter heart valve (THV) failure that should be avoided after transcatheter aortic valve implantation (TAVI). Although the effectiveness of direct oral anticoagulants (DOACs) on subclinical leaflet thrombosis has been demonstrated, there is insufficiently established evidence for post-TAVI antithrombotic therapy. The aim of this study was to clarify the formation process of subclinical leaflet thrombosis on THV and thrombogenicity during the perioperative period of TAVI. Methods: This multicenter, prospective, single-arm interventional study enrolled 26 patients with atrial fibrillation treated with edoxaban and severe aortic valve stenosis who underwent TAVI between September 2018 and September 2022. After exclusion, 24 patients were finally analyzed. We investigated changes in maximal leaflet thickness detected by contrast-enhanced computed tomography between 1 week and 3 months after TAVI and measured the thrombogenicity by Total Thrombus-formation Analysis System (T-TAS) and flow stagnation volume by computational fluid dynamics (CFD). Results: Of all, subclinical leaflet thrombosis was observed in 16.7% at 1 week, but decreased to 5.9% at 3 months after TAVI. There was no significant difference in maximum leaflet thickness between 1 week and 3 months, however, patients with subclinical leaflet thrombosis at 1 week had a significantly greater difference in that thickness compared to those without thrombosis. Thrombogenicity assessed by T-TAS and platelet count decreased markedly at 1 week and tended to improve at 3 months. Simple liner regression analysis showed that stagnation volume was positively associated with an increase in maximum leaflet thickness, and low-dose edoxaban was associated with a high risk of increased leaflet thickness at chronic phase. Conclusions: This study showed that course of leaflet thrombus formation in neo-sinus of THV and dynamic fluctuation of thrombogenicity in the acute phase after TAVI. These findings were merely hypotheses generation and thus necessitate future hypothesis testing with large sample sizes.

Evaluation of the anatomic sinus after transcatheter aortic valve replacement

BackgroundFollowing 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. Methods2D 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. ResultsThere 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. Conclusions2D 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-expanding and balloon-expandable valves in low risk TAVR patients

BackgroundRecent randomized studies have broadened the indication of transcatheter aortic valve replacement (TAVR) to also include low-surgical-risk patients. However, the data on self-expanding (SE) and balloon-expandable (BE) valves in low-risk patients remain sparse. MethodsThe current study is a post hoc analysis of combined data from both LRT 1.0 and 2.0 trials comparing BE and SE transcatheter heart valves. ResultsA total of 294 patients received a BE valve, and 102 patients received an SE valve. The 30-day clinical outcomes were similar across both groups except for stroke (4.9% vs. 0.7%, p = 0.014) and permanent pacemaker implantation (17.8% vs. 5.8%, p < 0.001), which were higher in the SE cohort than the BE cohort. No difference was observed in terms of paravalvular leak (≥moderate) between the groups (0% vs. 1.5%, p = 0.577). SE patients had higher aortic valve area (1.92 ± 0.43 mm2 vs. 1.69 ± 0.45 mm2, p < 0.001) and lower mean gradient (8.93 ± 3.53 mmHg vs. 13.41 ± 4.73 mmHg, p < 0.001) than BE patients. In addition, the rate of subclinical leaflet thrombosis was significantly lower in SE patients (5.6% vs. 13.8%, p = 0.038). ConclusionIn this non-randomized study assessing SE and BE valves in low-risk TAVR patients, SE valves are associated with better hemodynamics and lesser leaflet thrombosis, with increased rates of stroke and permanent pacemaker implantation at 30 days; however, this could be due to certain patient-dependent factors not fully evaluated in this study. The long-term implications of these outcomes on structural valve durability remain to be further investigated. Clinical Trial RegistryLRT 1.0: NCT02628899LRT 2.0: NCT03557242

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.

Aspirin Versus Warfarin after Transcatheter Aortic Valve Replacement in Low-Risk Patients: 2-Year Follow-Up

Subclinical leaflet thrombosis occurs with transcatheter heart valves (THVs) and could be associated with structural valve deterioration. The current guidelines recommend the use of antiplatelet agents after transcatheter aortic valve replacement (TAVR) but not the routine use of oral anticoagulation. Our study examines the effects of short-term warfarin therapy on THV hemodynamics at 24months after TAVR in low-risk patients. Low-risk patients who underwent TAVR were randomly allocated 1:1 to receive low-dose aspirin (n=50) or low-dose aspirin plus warfarin (n=44). After 30days of treatment, ongoing medication regimens, including anticoagulation, were at the physicians' discretion. Follow-up after a period of 24months was available for clinical and echocardiographic outcomes. At the 24-month mark, follow-up echocardiography of the randomly allocated patients revealed just 1 additional case of new structural valve deterioration in the aspirin group (compared with the occurrence within 30days), based on the Valve Academic Research Consortium 3 definitions. There were also no differences in mean pressure gradients (11.5 ± 0.5mm Hg vs 11.05 ± 4.0mm Hg, p=0.6) or peak velocity (2.2 ± 0.5m/s vs 2.1 ± 0.4m/s, p=0.7) between the groups. A composite end point (mortality, stroke, and myocardial infarction) did not show any difference between the groups at long-term follow-up (p=0.07). In conclusion, in low-risk patients who underwent TAVR, short-term anticoagulation with warfarin did not impact clinical outcomes or THV hemodynamics by echocardiography at 24months.

In silico model to assess thrombosis risk of TAVR with hemodynamic predictors using fluid structure interaction

Abstract The promising results of transcatheter aortic valve replacement (TAVR) over the past two decades indicate an expansion of the patient cohort toward patients with intermediate or low surgical risk. Since some complications of TAVR have already been minimized, subclinical leaflet thrombosis (SLT) has gained importance in recent years. SLT is manifested by a thrombotic layer on the prosthetic leaflets that gradually reduces leaflet motion. The resulting decrease in functionality of the TAVR causes a need for re-intervention. The origin of SLT and approaches to prevent SLT are still unexplored. For this reason, we have developed an in silicomodel that can be used during the design development process of TAVR devices to estimate the thrombosis risk of the implant. Based on passive scalar transport, hemodynamic metrics are used to quantify platelet activation and aggregation which are associated with the formation of thrombosis. In conjunction with a numerical simulation model considering the fluid-structure interaction between the blood mimicking fluid and the TAVR implanted in an aortic root, the thrombosis risk can be modeled. The simulation model can be used to calculate the three-dimensional flow structures within the native sinus and neo-sinus and also provides the ability to derive metrics to assess the risk of thrombosis. We demonstrated that this in silicomodel is a time-effective tool to assess thrombosis risk in TAVR product development.

Impact of leaflet thrombosis on valve haemodynamic status after transcatheter aortic valve replacement

ObjectivesThe effect of subclinical leaflet thrombosis, characterised by hypoattenuated leaflet thickening (HALT), on the valve haemodynamic function and durability of the bioprosthetic valve, is not yet determined. We determined the...

Correction to: Transcatheter Aortic Valve Replacement and Impact of Subclinical Leaflet Thrombosis in Low-Risk Patients: LRT Trial 4-Year Outcomes.

HomeCirculation: Cardiovascular InterventionsAhead of PrintCorrection to: Transcatheter Aortic Valve Replacement and Impact of Subclinical Leaflet Thrombosis in Low-Risk Patients: LRT Trial 4-Year Outcomes Free AccessCorrectionPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessCorrectionPDF/EPUBCorrection to: Transcatheter Aortic Valve Replacement and Impact of Subclinical Leaflet Thrombosis in Low-Risk Patients: LRT Trial 4-Year Outcomes Originally published16 Jun 2023https://doi.org/10.1161/HCV.0000000000000091Circulation: Cardiovascular Interventions. 2023;0:e000091This article corrects the followingTranscatheter Aortic Valve Replacement and Impact of Subclinical Leaflet Thrombosis in Low-Risk Patients: LRT Trial 4-Year OutcomesIn the article by Waksman et al, “Transcatheter Aortic Valve Replacement and Impact of Subclinical Leaflet Thrombosis in Low-Risk Patients: LRT Trial 4-Year Outcomes,” which appeared in the May 2023 issue of the journal (Circ Cardiovasc Interv.2023;16:e012655. doi: 10.1161/CIRCINTERVENTIONS.122.012655), a correction is needed.In Figure 1, there was an error. Instead of 202 patients, it should say 200. A corrected Figure has been posted.The authors regret this error.These corrections have been made to the current version of the article, which is available at https://www.ahajournals.org/doi/full/10.1161/CIRCINTERVENTIONS.122.012655. Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesTranscatheter Aortic Valve Replacement and Impact of Subclinical Leaflet Thrombosis in Low-Risk Patients: LRT Trial 4-Year OutcomesRon Waksman, et al. Circulation: Cardiovascular Interventions. 2023;16 Advertisement Article InformationMetrics © 2023 American Heart Association, Inc.https://doi.org/10.1161/HCV.0000000000000091PMID: 37327197 Originally publishedJune 16, 2023 PDF download Advertisement

Hypoattenuated Leaflet Thickening After Implantation of the ACURATE neo or the ACURATE neo2 Transcatheter Heart Valve

Subclinical leaflet thrombosis, identified as hypoattenuated leaflet thickening (HALT) on cardiac computed tomography scan, has been observed after transcatheter aortic valve replacement (TAVR). However, data on HALT after the implant of the supra-annular ACURATE neo/neo2 prosthesis are limited. This study aimed to determine the prevalence and risk factors for the development of HALT after TAVR with the ACURATE neo/neo2. A total of 50 patients who received the ACURATE neo/neo2 prosthesis were prospectively enrolled. Patients underwent a contrast-enhanced multidetector row cardiac computed tomography scan at before, after, and 6months after TAVR. At the 6-month follow-up, HALT was detected in 16% (8 of 50 patients). These patients had a lower implant depth of the transcatheter heart valve (8 ± 2mm vs 5 ± 2mm, p=0.001), less calcified native valve leaflets, a better expansion of the frame at the level of the left ventricular outflow tract, and were less often hypertensive. Thrombosis of the sinus of Valsalva occurred in 18% (9/50). There was no difference in the anticoagulation regimen between patients with and without thrombotic findings. In conclusion, HALT was present in 16% of patients at 6months follow-up, patients presenting with HALT had a lower implant depth of the transcatheter heart valve, and HALT was detected in patients on oral anticoagulation therapy.

Early Detection of Risk of Neo-Sinus Blood Stasis Post-Transcatheter Aortic Valve Replacement Using Personalized Hemodynamic Analysis

BackgroundDespite the demonstrated benefits of transcatheter aortic valve replacement (TAVR), subclinical leaflet thrombosis and hypoattenuated leaflet thickening are commonly seen as initial indications of decreased valve durability and augmented risk of transient ischemic attack. MethodsWe developed a multiscale patient-specific computational framework to quantify metrics of global circulatory function, metrics of global cardiac function, and local cardiac fluid dynamics of the aortic root and coronary arteries. ResultsBased on our findings, TAVR might be associated with a high risk of blood stagnation in the neo-sinus region due to the lack of sufficient blood flow washout during the diastole phase (e.g., maximum blood stasis volume increased by 13, 8, and 2.7 fold in the left coronary cusp, right coronary cusp, and noncoronary cusp, respectively [N = 26]). Moreover, in some patients, TAVR might not be associated with left ventricle load relief (e.g., left ventricle load reduced only by 1.2 % [N = 26]) and diastolic coronary flow improvement (e.g., maximum coronary flow reduced by 4.94%, 15.05%, and 23.59% in the left anterior descending, left circumflex coronary artery, and right coronary artery, respectively, [N = 26]). ConclusionsThe transvalvular pressure gradient amelioration after TAVR might not translate into adequate sinus blood washout, optimal coronary flow, and reduced cardiac stress. Noninvasive personalized computational modeling can facilitate the determination of the most effective revascularization strategy pre-TAVR and monitor leaflet thrombosis and coronary plaque progression post-TAVR.

Commissural misalignment independently predicts leaflet thrombosis after transcatheter aortic valve implantation.

Transcatheter aortic valve implantation (TAVI) has become a minimally invasive alternative to surgical aortic valve replacement. Hypo-attenuated leaflet thickening (HALT)-a marker of subclinical leaflet thrombosis commonly detected by cardiac computed tomography (CT) after TAVI-may influence valve durability and function. The purpose of this study was to compare commissural alignment of the native and prosthetic aortic valves in cardiac CT in subjects with and without HALT and thereby identify commissural misalignment as potential predictor for leaflet thrombosis after TAVI. In 170 subjects, 85 with and 85 without HALT in post-TAVI CT, commissural orientation of the prosthesis was determined comparing native and prosthetic aortic valve orientation in cardiac CT by measuring the commissural angle relative to the right coronary ostium in the aortic valve plane. For the prosthetic valve, any deviation ≤ 15° compared to the native valve was classified as "aligned"; 16-30° as "mild", 31-45° as "moderate" and ≥ 45° as "severe" misalignment. Among subjects with HALT, median angular deviation was higher (36°, IQR 31°) than in the control group (29°, IQR 29°, p = 0.042). "Severe" misalignment was more frequent in subjects who developed HALT (n = 31, 37%) compared to the control group (n = 17, 20%, p = 0.013). In logistic regression analysis, more severe deviation (p = 0.015, OR = 1.02 per 1° deviation) and "severe" misalignment (p = 0.018, OR = 2.2) represented independent predictors for the occurrence of HALT after TAVI. Subclinical leaflet thrombosis after TAVI is associated with commissural misalignment. Potential clinical advantages of obtaining commissural alignment remain to be systematically assessed.

A model of fluid-structure and biochemical interactions for applications to subclinical leaflet thrombosis.

Subclinical leaflet thrombosis (SLT) is a potentially serious complication of aortic valve replacement with a bioprosthetic valve in which blood clots form on the replacement valve. SLT is associated with increased risk of transient ischemic attacks and strokes and can progress to clinical leaflet thrombosis. SLT following aortic valve replacement also may be related to subsequent structural valve deterioration, which can impair the durability of the valve replacement. Because of the difficulty in clinical imaging of SLT, models are needed to determine the mechanisms of SLT and could eventually predict which patients will develop SLT. To this end, we develop methods to simulate leaflet thrombosis that combine fluid-structure interaction and a simplified thrombosis model that allows for deposition along the moving leaflets. Additionally, this model can be adapted to model deposition or absorption along other moving boundaries. We present convergence results and quantify the model's ability to realize changes in valve opening and pressures. These new approaches are an important advancement in our tools for modeling thrombosis because they incorporate both adhesion to the surface of the moving leaflets and feedback to the fluid-structure interaction.

Risk factors and clinical effects of subclinical leaflet thrombosis after transcatheter aortic valve replacement.

The number of trans-catheter aortic valve replacement (TAVR) procedure is increasing; However, the incidence of leaflet thrombosis is higher in TAVR than in surgical aortic valve replacement (SAVR). In this study, the risk factors for leaflet thrombosis after TAVR and its effects on hemodynamics and clinical course were investigated. Multidetector computed tomography (MDCT) was performed at 1year after TAVR in 94 patients from January 2015 to October 2020 at Samsung Medical Center in South Korea. Among the 94 patients, subclinical leaflet thrombosis occurred in 20 patients, and risk factors were analyzed. In addition, the difference in aortic valve (AV) hemodynamics between the two groups was examined and clinical outcomes compared. Indexed mean sinus of Valsalva (SOV) diameter, AV calcium volume, and post-procedure effective orifice area (EOA) were predictive of subclinical leaflet thrombosis with the area under the curve (AUC) value of 0.670 (P-value = 0.020), 0.695 (P-value = 0.013), and 0.665 (P-value = 0.031), respectively. In echocardiography performed at the time of follow-up CT, the value of AV max velocity and AV mean pressure gradient were higher in the thrombosis group and the EOA and Doppler velocity index values were lower in the thrombosis group than in the no thrombosis group. Clinical outcome was not significantly different between the two groups (log-rank P-value = 0.26). Larger indexed SOV diameter, higher AV calcium volume, and smaller post-procedure AV EOA were risk factors for subclinical leaflet thrombosis after TAVR. Subclinical leaflet thrombosis has a benign course when properly managed.

Abstract 14851: Risk Factors and Clinical Effects of Leaflet Thrombosis After Transcathether Aortic Valve Replacement

Introduction: The incidence of leaflet thrombosis is higher in TAVR than in SAVR; however, knowledge regarding the risk factors of leaflet thrombosis in TAVR is limited. Hypothesis: In this study, the incidence and risk factors for leaflet thrombosis after TAVR and its effects on clinical course were investigated. Methods: 176 patients who underwent TAVR from January 2015 to October 2020 were enrolled. Follow-up MDCT was performed between 3 months and 2 years after TAVR in 94 patients. Among the 94 patients, leaflet thrombosis occurred in 20 patients, and risk factors were analyzed by comparing clinical factors, echocardiographic parameters, 4D-MDCT information, and angiographic data between thrombosis group and no thrombosis group. Clinical outcome was defined as the composite of all-cause death, stroke, HF admission, redo AVR, and major bleeding after detection of leaflet thrombosis. Results: Indexed mean SOV diameter, AV calcium volume, and post-procedure EOAi were predictive of leaflet thrombosis with AUC value of 0.670 (95% CI 0.546 - 0.795, P -value = 0.020), 0.695 (95% CI 0.541 - 0.850, P -value = 0.012), and 0.665 (95% CI 0.548 - 0.782, P -value = 0.031), respectively. In echocardiography performed at the time of follow-up CT, the value of AV max velocity and AV mean pressure gradient were higher in the thrombosis group and the EOAi and Doppler velocity index values were lower in the thrombosis group than in the no thrombosis group. All the median echocardiographic values in both groups were within normal range. All patients with leaflet thrombosis were in subclinical status and half changed medication after detection. Clinical outcome was not significantly different between the two groups (log-rank P -value = 0.26). Conclusions: Larger indexed SOV diameter, higher AV calcium volume, and smaller post-procedure AV EOAi were risk factors for leaflet thrombosis after TAVR. Subclinical leaflet thrombosis has a benign course when properly managed.

On the Three-dimensionality of Flow in the Neo-sinus and its Implications for Subclinical Leaflet Thrombosis.

Subclinical leaflet thrombosis is a silent phenomenon commonly observed following transcatheter aortic valve implantation (TAVI). Leaflet thrombosis is associated with ischaemic complications and structural valve deterioration. Prior studies have shown that blood stasis in neo-sinus contributes to the initiation and growth of subclinical leaflet thrombosis. This study aimed to quantify temporal and spatial characteristics of the flow field from a fundamental perspective. in vitro experimental analysis and fluid-solid interaction simulations were employed to characterize the flow field of a transcatheter aortic valve (TAV) with an intra-annular design in a pulse duplicator. Blood residence time (BRT) and flow-induced viscous shear stress were measured in the neo-sinus and on the surface of TAV leaflets. Temporal and spatial velocity variations were observed in neo-sinus, indicating that the flow is time-dependent and fully three-dimensional. The degree of blood stasis in the neo-sinus (bulk fluid) and on the surface of the TAV leaflets highly depends on the local flow characteristics. Regional flow variation in the neo-sinus resulted in substantial variations in BRT magnitude in the neo-sinus and on the surface of the TAV leaflet. Areas with a high degree of blood stasis were observed near the fixed boundary edge of the leaflets. The study indicated that leaflet motion is a primary driver of flow in neo-sinus. Considering the substantial variations in BRT magnitude in the neo-sinus (bulk fluid), blood stasis should be quantified locally on the surface of foreign (valve) materials to avoid errors in forecasting the risk of subclinical leaflet thrombosis in patients undergoing TAVI.

Subclinical leaflet thrombosis and antithrombotic therapy post-TAVI: An LRT substudy

BackgroundSubclinical leaflet thrombosis (SLT) is characterized on computed tomography (CT) imaging as hypoattenuated leaflet thickening (HALT), reduced leaflet motion (RELM), and hypoattenuation affecting motion (HAM). How antithrombotic regimen type impacts SLT remains poorly understood. We evaluated how antithrombotic regimen type impacts SLT in low-risk subjects following transcatheter aortic valve implantation (TAVI). MethodsThis substudy is a post hoc analysis of the LRT 1.0 and 2.0 trials to assess SLT in subjects who underwent CT or transoesophageal echocardiogram (TOE) imaging at 30 days, stratified by antithrombotic regimen received (single antiplatelet therapy [SAPT], dual antiplatelet therapy [DAPT], or oral anticoagulation). We also utilized univariable logistic regression modelling to identify echocardiographic predictors of HALT. ResultsRates of HALT, RELM, and HAM were all significantly lower with oral anticoagulation compared to SAPT or DAPT at 30 days (HALT: 2.6% vs 14.3% vs 17.2%, respectively, with p < 0.001; RELM: 1.8% vs 9.6% vs 13.1%, respectively, with p = 0.004; and HAM: 0.9% vs 8.5% vs 9.8%, respectively, with p = 0.011). Additionally, short-term oral anticoagulation was not associated with higher bleeding rates compared to SAPT or DAPT (0.8% vs. 1.8% vs. 3.6%, p = 0.291). The presence of HALT did not significantly impact echocardiographic haemodynamic parameters at 30 days. ConclusionThis is the largest study to date that evaluated the impact of different antithrombotic regimens on SLT in low-risk TAVI patients. Oral anticoagulation was associated with significantly lower rates of SLT at 30 days compared to DAPT or SAPT, and there was no apparent benefit of DAPT over SAPT.