Hypoattenuated Leaflet Thickening: A Comprehensive Review of Contemporary Data.

Nearly one-third of patients who undergo surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR) develop hypoattenuated leaflet thickening (HALT) within a year. HALT typically represents subclinical leaflet thrombosis in asymptomatic patients, and as a result it often is detected incidentally. However, HALT also may worsen in severity, resulting in leaflet immobility and/or valve deterioration. The clinical significance of HALT is a topic of ongoing debate, and currently there is no consensus on the screening and management of HALT in patients following TAVR or SAVR. This review provides a comprehensive evaluation of the available evidence on risk factors, preventative measures, treatment, and prognosis for this growing patient cohort.

Prosthesis Geometrical Predictors of Leaflet Thrombosis Following Transcatheter Aortic Valve Replacement With Intra-Annular Prostheses.

OBJECTIVE: To determine the association between prosthesis geometry with leaflet thrombosis (LT). BACKGROUND: Leaflet thrombosis following transcatheter aortic valve replacement (TAVR) is a recognised entity. The association between prosthesis geometry with LT is unclear but maybe a potential modifiable factor in its prevention. METHODS: Patients who received an intra-annular TAVR prosthesis and were prospectively planned to undergo post-procedural computed tomography (CT) imaging were included. Leaflet thrombosis was defined as at least 50% restricted leaflet motion on CT. Prosthesis expansion and eccentricity was measured at prosthesis inflow, annulus and outflow levels. Prosthesis misalignment was defined as the average angle deviation between native and prosthesis leaflet commissure, greater than 30°. RESULTS: Prevalence of LT was 13.7% in 117 patients. None of the patients with LT were on anticoagulation therapy. Patients with LT had reduced prosthesis annular expansion (89.4±5.2% vs 97.0±4.4%, p<0.01), greater prosthesis misalignment (81.3% vs 48.5%, p=0.02) and deeper implants (6.3±1.7 mm vs 4.3±1.5 mm, p<0.01). Threshold for the presence of LT on ROC analysis was an implant depth of 5.7 mm (AUC [area under curve]=0.81). Independent predictors of LT were annular under-expansion (Odds ratio [OR] 1.4, 95% confidence interval [CI] 1.2-1.7, p=0.03) prosthesis misalignment (OR 6.8, 95%CI 1.1-45.5, p=0.04) and implant depth (OR 1.9, 95%CI 1.1-3.2, p=0.03). Anticoagulation therapy was a protective factor (OR 0.2; 95%CI 0.1-0.4, p<0.01). CONCLUSION: Geometrical predictors of LT post intra-annular TAVR were reduced prosthesis expansion at the annular level, lower implant depth and greater prosthesis misalignment. These factors may be important considerations during procedural planning for TAVR.

Clinical predictors and sequelae of computed tomography defined leaflet thrombosis following transcatheter aortic valve replacement at medium-term follow-up.

BACKGROUND: The clinical predictors and sequelae of leaflet thrombosis (LT) following transcatheter aortic valve replacement (TAVR) is still unclear. Therefore, our aim was to determine the clinical predictors and sequelae at mid-term follow-up of computed tomography (CT)-defined LT following TAVR. METHODS AND RESULTS: We performed a prospective evaluation with a 320-multislice CT following TAVR for the presence of LT, defined as hypo-attenuated leaflet thickening (HALT). Four-dimensional CT image-rendering was performed to determine the presence of reduced leaflet motion (RELM). 172 patients [89 (51.7%) male, mean age 82.8 ± 5.7 years] treated with commercially available TAVR device (Lotus 54%, CoreValve 32% and Sapien 3 14%) were included, with median CT-scan at 6.0 weeks post-TAVR. Prevalence of HALT was 14.0% (24 cases) and RELM was 9.8% (17 cases). On multivariate analysis, patients with HALT were less prescribed oral anticoagulation (OAC) (OR 9.9), received larger TAVR prostheses (OR 5.7) and higher rates of moderate-severe para-valvular regurgitation (PVR) (OR 16.3). There was no difference in clinical outcomes at a median follow-up of 2.3 years. Patients with RELM had significantly higher transvalvular gradients after discharge when compared to those without RELM. CONCLUSIONS: Absence of OAC, large TAVR prostheses and moderate-severe PVR were predictors for LT. Transvalvular gradients were higher in patients that developed RELM but not HALT. Further studies are warranted to determine the long-term impact of LT on TAVR durability. Prevalence of different sub-types of CT-defined LT (HALT and RELM) and the clinical predictors of developing LT following TAVR. CT computed tomography, HALT hypo-attenuated leaflet thickening, LT leaflet thrombosis, RELM reduced leaflet motion, TAVR transcatheter aortic valve replacement.

Anticoagulation Therapy After Transcatheter Aortic Valve Replacement.

PURPOSE OF REVIEW: We review the prevalence; natural history; impact of subclinical clinical thrombosis on valve hemodynamics, clinical outcomes, and valve durability; and the role of anticoagulation after transcatheter aortic valve replacement (TAVR). RECENT FINDINGS: Subclinical leaflet thrombosis is a dynamic finding present in both transcatheter and surgical bioprosthetic aortic valves. This finding is less prevalent in patients on anticoagulation and resolves following initiation of anticoagulation. Routine anticoagulation after TAVR in high-surgical-risk patients was associated with increased mortality and thromboembolic complications. In the absence of a clinical indication for anticoagulation, there is no reason to initiate anticoagulation after TAVR for the prevention of subclinical leaflet thrombosis. In patients with an established indication for anticoagulation, for instance, atrial fibrillation, clinical or symptomatic valve thrombosis, or a clinical event related to valve thrombosis, anticoagulation should be initiated or continued after TAVR to treat the clinical indication.

The prevalence of computed tomography-defined leaflet thrombosis in intra- versus supra-annular transcatheter aortic valve prostheses.

INTRODUCTION: Leaflet thrombosis (LT) defined by computed tomography (CT) following transcatheter aortic valve replacement (TAVR) has been shown to increase cerebrovascular events. The neo-sinus plays an important role in the development of LT. Intra-annular valves (IAV) have a larger neo-sinus when compared to supra-annular valves (SAV), and has been associated with larger thrombus burden. The prevalence of LT with IAV and SAV in a larger, diverse cohort is unknown. METHODS: We performed a systematic review to assess the prevalence of LT in IAV versus SAV TAVR prostheses. Inclusion criteria were (1) reported CT-defined LT following TAVR, (2) comparison between LT and non-LT cohort, (3) separate registry/database, and (4) fully published status. A total of 2,013 citations were reviewed and 7 studies were included. RESULTS: Overall, 1,644 patients were included from 7 observational studies and the prevalence of LT following TAVR was 12.8%. The Portico valve system (IAV) had the highest prevalence of LT with 35.2%, followed by Symetis Acurate Neo (SAV) at 15.4% and the Lotus valve system (IAV) at 14.5%. LT occurred more frequently in IAV than SAV (13.5% vs. 7%, P = 0.02). Subanalysis of IAV versus SAV with the exclusion of the Portico valve was performed to ensure results were not influenced by this valve system and revealed IAV still had higher rates of LT (12.1% vs. 7%, P = 0.05). CONCLUSION: In summary, IAV prostheses appear to be associated with higher rates of LT when compared with SAV.

Subclinical leaflet thrombosis following transcatheter aortic valve replacement.

Since the inception of transcatheter aortic valve replacement (TAVR), there have been significant reductions in complications due to improvements of transcatheter heart valve (THV) designs and technologies. Given expanding TAVR applications, reducing complications further and better understanding THV durability has become a focus within the structural heart space. Recently, dedicated cardiac computed tomographic angiography (CTA) performed at 1 month post-TAVR has identified subclinical leaflet thrombosis (SLT), with rates as high as 40%. From the SLT imaging hallmarks of hypoattenuated leaflet thickening (HALT) to hypoattenuation affecting motion (HAM), a postulated timeline of THV thrombosis advancing to clinical symptoms can be recognized. This review article focuses on leaflet thrombosis particularly following TAVR explaining the spectrum of this disease process, its diagnosis, current treatment options, and future directions in the field.

Successful Apixaban Treatment of TAVR Thrombosis after Warfarin Failure.

In this study, we present a case of progressive transcatheter aortic valve replacement thrombosis in a patient receiving warfarin that resolved with treatment with heparin and apixaban.

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

AIMS: 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. METHODS AND RESULTS: 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. CONCLUSION: Subclinical leaflet thrombosis after TAVI is associated with commissural misalignment. Potential clinical advantages of obtaining commissural alignment remain to be systematically assessed.

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.

Early thrombus formation including hypo-attenuated leaflet thrombosis after surgical bioprosthetic aortic valve replacement.

OBJECTIVE: To assess the occurrence, predictors, and outcomes of hypo-attenuated leaflet thickening (HALT) and thrombus outside the prosthetic valve following surgical aortic valve replacement. METHODS: A total of 118 patients underwent surgical aortic valve replacement with bioprosthetic valves between July 2020 and June 2022. Sixty-two (52.5%) patients, which is a fairly high number of patients, underwent cardiac computed tomography and transthoracic echocardiography one week after surgery. Patients were divided into two groups, those with HALT (n = 14) and those without HALT (n = 48). RESULTS: Of the 62 patients who underwent cardiac computed tomography, HALT was observed in 14 (22.5%) patients during the very early postoperative phase. Reduced leaflet motion was observed in two of the 14 patients. The low-attenuation areas were located outside the prosthetic valve in 10 cases (71.4%) in the HALT group and in 14 cases (29.2%) in the non-HALT group. More than 50% of patients (57.1%) with HALT and 79.2% without HALT were administered warfarin. Neither in-hospital deaths nor postoperative thromboembolic events were observed during hospitalization. No patient had a mean pressure gradient > 20 mmHg in either group. CONCLUSION: HALT was observed in one-fifth of the cases after surgical aortic valve replacement during the very early postoperative phase in an institution wherein administration of continuous heparin infusion after surgery is a standard practice. HALT did not affect the early prognosis or incidence of cerebral infarction.

Subclinical leaflet thrombus in patients with severe aortic stenosis and atrial fibrillation -ENRICH-AF TAVI study.

Subclinical leaflet thrombosis (SLT) can be one of the causes of transcatheter heart valve (THV) failure after transcatheter aortic valve implantation (TAVI). We sought to clarify the formation process of SLT and thrombogenicity during the perioperative period of TAVI. This multicenter, prospective, single-arm interventional study enrolled 26 patients treated with edoxaban for atrial fibrillation and who underwent TAVI for severe aortic stenosis between September 2018 and September 2022. We investigated changes in maximal leaflet thickness detected by contrast-enhanced computed tomography between 1 week and 3 months after TAVI in 18 patients and measured the thrombogenicity by Total Thrombus-formation Analysis System (T-TAS) and flow stagnation volume by computational fluid dynamics (CFD) (n = 11). SLT was observed in 16.7% (3/18) at 1 week, but decreased to 5.9% (1/17) at 3 months after TAVI. Patients with SLT at 1 week had a significantly decreased maximal leaflet thickness compared to those without SLT. Thrombogenicity assessed by T-TAS decreased markedly at 1 week and tended to increase at 3 months. The stagnation volume assessed by CFD was positively associated with a higher maximum leaflet thickness. This study showed the course of leaflet thrombus formation and visualization of stagnation in neo-sinus of THV in the acute phase after TAVI.

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.

Prediction model for leaflet thrombosis in patients undergoing transcatheter aortic valve implantation: the EFFORT study.

BACKGROUND: Leaflet thrombosis (LT) is a multifaceted and underexplored condition that can manifest following transcatheter aortic valve implantation (TAVI). The objective of this study was to formulate a prediction model based on laboratory assessments and clinical parameters, providing additional guidance and insight into this relatively unexplored aspect of post-TAVI complications. METHODS: The present study was an observational prospective hypothesis-generating study, including 101 patients who underwent TAVI and a screening for LT (the primary endpoint) by multidetector computed tomography (MDCT). All images were acquired on a third-generation dual-source CT system. Levels of von Willebrand factor (vWF) activity, hemoglobin (Hb), and lactate dehydrogenase (LDH) were measured among other parameters. A predictive score utilizing binary logistic regression, Kaplan-Meier time-to-event analysis, and receiver operating characteristics (ROC) analysis was established. RESULTS: LT (11 subclinical and 2 clinical) was detected in 13 of 101 patients (13%) after a median time to screening by MDCT of 105 days (IQR, 98-129 days). Elevated levels of vWF activity (> 188%) pre-TAVI, decreased Hb values (< 11.9 g/dL), as well as increased levels of LDH (> 312 U/L) post-TAVI and absence of oral anticoagulation (OAC) were found in patients with subsequent LT formation as compared to patients without LT. The established EFFORT score ranged from - 1 to 3 points, with an increased probability for LT development in patients with ≥ 2 points (85.7% of LT cases) vs < 2 points (14.3% of LT cases; p < 0.001). Achieving an EFFORT score of ≥ 2 points was found to be significantly associated with a 10.8 times higher likelihood of developing an LT (p = 0.001). The EFFORT score has an excellent c-statistic (area under the curve (AUC) = 0.89; 95% CI 0.74-1.00; p = 0.001) and a high negative predictive value (98%). CONCLUSION: An EFFORT score might be a helpful tool to predict LT development and could be used in risk assessment, if validated in confirmatory studies. Therefore, the score has the potential to guide the stratification of individuals for the planning of subsequent MDCT screenings.

Treatment of Transcatheter Aortic Valve Thrombosis: JACC Review Topic of the Week.

Transcatheter aortic valve (TAV) thrombosis may manifest as subclinical leaflet thrombosis (SLT) and clinical valve thrombosis. SLT is relatively common (10%-20%) after transcatheter aortic valve replacement, but clinical implications are uncertain. Clinical valve thrombosis is rare (1.2%) and associated with bioprosthetic valve failure, neurologic or thromboembolic events, heart failure, and death. Treatment for TAV thrombosis has been understudied. In principle, anticoagulation may prevent TAV thrombosis. Non-vitamin K oral anticoagulants, as compared to antiplatelet therapy, are associated with reduced incidence of SLT, although at the cost of higher bleeding and all-cause mortality risk. We present an overview of existing literature for management of TAV thrombosis and propose a rational treatment algorithm. Vitamin K antagonists or non-vitamin K oral anticoagulants are the cornerstone of antithrombotic treatment. In therapy-resistant or clinically unstable patients, ultraslow, low-dose infusion of thrombolytics seems effective and safe and may be preferred over redo-transcatheter aortic valve replacement or explant surgery.

Self-expanding and balloon-expandable valves in low risk TAVR patients.

BACKGROUND: Recent 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. METHODS: The 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. RESULTS: A 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). CONCLUSION: In 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 REGISTRY: LRT 1.0: NCT02628899 LRT 2.0: NCT03557242.

Leaflet thrombosis in transcatheter aortic valve intervention: mechanisms, prevention, and treatment options.

Introduction: Transcatheter aortic valve intervention (TAVR) has emerged as a promising alternative to surgical aortic valve replacement for patients with severe aortic stenosis. However, leaflet thrombosis has raised concerns about the long-term durability and outcomes of TAVR. This study aims to provide an overview of the mechanisms, prevention strategies, and treatment options for leaflet thrombosis in TAVR. Clinical evidence: Leaflet thrombosis refers to the formation of blood clots on bioprosthetic valve leaflets, leading to impaired leaflet mobility, early valve degeneration and dysfunction, and potential clinical implications. While the mechanisms underlying thrombus formation on valve leaflets are not fully understood, several factors, such as altered blood flow patterns within valve neosinuses, prothrombotic surfaces, and patient-related causes, have been implicated. Two distinct entities have been identified, namely, hypoattenuated leaflet thickening and restricted leaflet motion. Their occurrence appears dynamic over time and is related to the valve type. Imaging, including transesophageal echocardiography and multidetector computed tomography, plays a crucial role in the diagnosis and follow-up of leaflet thrombosis. Prevention and treatment options: Preventing leaflet thrombosis requires a comprehensive and tailored approach involving identifying high-risk patients, close monitoring, and antithrombotic therapy. Antithrombotic therapy with dual antiplatelet agents or anticoagulation is commonly employed in TAVR patients, although the optimal regimen is yet to be defined. Novel antithrombotic agents, such as direct oral anticoagulants, are being investigated for their efficacy and safety in preventing leaflet thrombosis. When leaflet thrombosis is detected, treatment options include intensified antithrombotic therapy, valve-in-valve intervention, or balloon valvuloplasty. The long-term outcomes and impact of leaflet thrombosis on valve durability and patient prognosis are areas of ongoing research. Summary: Leaflet thrombosis in TAVR is a considerable complication affecting valve function and patient outcomes. Understanding the mechanisms underlying thrombus formation and implementing appropriate prevention strategies are essential for mitigating this risk. Treatment options aim to restore leaflet mobility and optimize valve performance. Further research is needed to establish standardized protocols for antithrombotic therapy, identify high-risk patient populations, and determine the long-term consequences of leaflet thrombosis on TAVR outcomes.

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

Background: Subclinical leaflet thrombosis occasionally occurs after transcatheter aortic valve implantation (TAVI), but its exact etiology and relationship with thrombogenicity remain unknown. Methods and Results: This study enrolled 35 patients who underwent TAVI. Thrombogenicity was evaluated using a total thrombus-formation analysis system (T-TAS) to compute the thrombus-formation area under the curve (PL18-AUC10 and AR10-AUC30). Periprocedural thrombogenic parameters including T-TAS were investigated at pre-TAVI, 2 days, 7 days, and 3 months post-TAVI. Hypoattenuated leaflet thickening (HALT) and maximum leaflet thickness (MLT) were evaluated using contrast-enhanced computed tomography 7 days and 3 months post-TAVI. The associations between thrombogenicity and HALT or MLT were assessed. T-TAS parameters consistently decreased at 2 and 7 days post-TAVI, followed by improvement at 3 months. HALT was detected in 20% and 17% of patients at 7 days and 3 months, respectively, post-TAVI. The median MLT value was 1.60 mm at 7 days and 3 months post-TAVI. A significant positive correlation was observed between the decrease in the AR10-AUC30 and MLT at 7 days post-TAVI. Univariate linear regression analysis revealed a decrease in the AR10-AUC30 and an increase in the D-dimer level as a significant predictor of MLT deterioration. Conclusions: The findings suggested that a transient decrease in thrombogenicity following TAVI predicts leaflet thrombosis, implying that monitoring thrombogenicity may be useful for predicting progression of leaflet thrombosis.

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.

Computed tomography imaging for subclinical leaflet thrombosis following surgical and transcatheter aortic valve replacement.

Subclinical leaflet thrombosis (LT) may occur following surgical and transcatheter aortic valve replacement. Computed tomography (CT) has become an established imaging modality to diagnose subclinical LT following bioprosthetic aortic valve replacement. Even so, there is a limited (but growing) experience in utilizing CT imaging for this indication. This review emphasizes a systematic approach to acquiring and analysing CT imaging for subclinical LT, highlighting evidence surrounding clinical sequelae of subclinical LT and anti-thrombotic implications following diagnosis.