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

Commissural Alignment in SAPIEN 3 Valves: Impact on Gradient and Mortality at Follow-Up

BACKGROUND

Commissural misalignment (CMA) has demonstrated to difficult future coronary access in self-expandable prosthesis and has been related with subclinical leaflet thrombosis and a potential increase in valve gradients and aortic regurgitation at follow-up.

AIMS

The aim of our study was to assess the commissural alignment of the balloon expandable SAPIEN 3 valve (Edwards Lifesciences) and to evaluate its impact on transvalvular gradient and mortality at 5 years of follow-up.

METHODS

Consecutive patients treated with SAPIEN 3 prosthesis guided with intraprocedural transesophageal echocardiogram (TEE) with a minimal follow-up of 5 years were included. Commissural alignment between the prosthesis and the native valve was measured by TEE by two independent cardiologists using a standardized 3-cusp view pre and post-valve deployment. CMA was defined as a neocommissure deviation > 30° compared with native commissures. Echocardiographic gradients and clinical events were recorded during follow-up and compared between groups.

RESULTS

One hundred and five patients (54% male, mean age 80.4 years) were included; 63 (40%) were classified as "aligned" (CMA < 30°) and 42 (60%) as "misaligned" (CMA > 30°). Patients with CMA > 30° presented smaller aortic annulus (23.8 vs. 20.7, p < 0.01) and received smaller valves. There was a slight increase of mean transvalvular gradient during follow-up (9.2-10.3 mmHg, p < 0.05), without significant differences between groups. Mortality rate was 16.2% at 1 year and 49.5% at 5 years; and not related to commissural alignment.

CONCLUSIONS

Significant CMA is present in 40% of patients treated with SAPIEN 3 valves, however, we didn't find a significant association between CMA and gradient increase or mortality during long-term follow-up.

Valvular and perivalvular thrombosis following self-expandable aortic valve replacement: analysis of 100 multi-detector computed tomography scans

Aims

Subclinical thrombosis may represent an early stage of prosthesis structural disease. Most of the available evidence on the incidence, location, predictors, and consequences of thrombosis comes from studies that have employed balloon-expandable valves. We aimed to describe the different localisations of valvular and perivalvular thrombosis and analyse prosthesis-host multi-detector computed tomography predictors in the context of self-expandable prosthesis. Additionally, we aimed to assess the impact of valvular and perivalvular thrombosis on prosthesis performance and subsequent clinical outcomes.

Methods and results

This analysis includes 100 consecutive patients with normal renal function who underwent transcatheter aortic valve replacement using Evolut R and received multi-detector computed tomography and transthoracic bi-dimensional echocardiography at the 6 month follow-up. Leaflet thrombosis was detected in 18 (18%) patients; 6 (6%) had at least one leaflet with severe thrombosis. Thrombosis of the anatomic sinus was detected in 24 patients (24%) and was more prevalent in the non-coronary sinus. Subvalvular thrombosis with partial or complete circumferential involvement of the prosthesis inner skirt was diagnosed in 23 patients (23%). Bicuspid valve was the predictor with highest association with hypoattenuated lesions [least absolute shrinkage and selection operator coefficient 0.35, 95%, confidence interval (CI) 0.21-0.68]. There was no difference in terms of haemodynamic structural valve dysfunction, neurological events, and re-hospitalisation between the groups with and without thrombosis (hazard ratio: 0.86, 95% CI: 0.24-3.06, P = 0.82).

Conclusion

This study showed that in a relatively low-risk population, valvular and perivalvular thrombosis were not rare phenomena following transcatheter aortic valve replacement at early follow-up. Bicuspid valve showed the strongest association with post-implant thrombosis.

Cardiac computed tomography post-transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) is performed to treat aortic stenosis and is increasingly being utilised in the low-to-intermediate-risk population. Currently, attention has shifted towards long-term outcomes, complications and lifelong maintenance of the bioprosthesis. Some patients with TAVR in-situ may develop significant coronary artery disease over time requiring invasive coronary angiography, which may be problematic with the TAVR bioprosthesis in close proximity to the coronary ostia. In addition, younger patients may require a second transcatheter heart valve (THV) to 'replace' their in-situ THV because of gradual structural valve degeneration. Implantation of a second THV carries a risk of coronary obstruction, thereby requiring comprehensive pre-procedural planning. Unlike in the pre-TAVR period, cardiac CT angiography in the post-TAVR period is not well established. However, post-TAVR cardiac CT is being increasingly utilised to evaluate mechanisms for structural valve degeneration and complications, including leaflet thrombosis. Post-TAVR CT is also expected to have a significant role in risk-stratifying and planning future invasive procedures including coronary angiography and valve-in-valve interventions. Overall, there is emerging evidence for post-TAVR CT to be eventually incorporated into long-term TAVR monitoring and lifelong planning.

Subclinical leaflet thrombosis and anticoagulation strategy following trans-catheter aortic valve replacement: A systematic review

Objective

Subclinical leaflet thrombosis (SLT) develops in 15% of patients undergoing trans-catheter aortic valve replacement (TAVR). TAVR is a procedure in which a faulty aortic valve is replaced with a mechanical one. An aortic valve replacement can be done with open-heart surgery; this is called surgical aortic valve replacement (SAVR). A significant problem is defining the best course of treatment for asymptomatic individuals with SLT post-TAVR, including the use of oral anticoagulation (OAC) in it.

Study design

Systematic review.

Method

The most pertinent published research (original papers and reviews) in the scientific literature were searched for and critically assessed using the online, internationally indexed databases PubMed, Medline, and Cochrane Reviews. Keywords like "Transcatheter valve replacement" and "Subclinical leaflet thrombosis" were used to search the papers. Selected studies were critically assessed for inclusion based on predefined criteria.

Results

The review examined the prevalence and characteristics of SLT after TAVR. To note, the incidence of SLT is seen to be higher in TAVR compared SAVR. Dual antiplatelet therapy, which is utilized in antithrombotic regimens post-TAVR, can possibly hasten SLT progression which could result in the impaired mobility of leaflets and the worsening of pressure gradients.

Conclusion

The use of dual antiplatelet drugs in routine antithrombotic therapy tends to accelerate initial subclinical leaflet thrombosis after TAVI, which results in a developing restriction of leaflet mobility and an increase in pressure differences.

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.

The Incidence, Impact, and Techniques of Commissural Alignment in Transcatheter Aortic Valve Implantation: A Review

In current clinical practice, commissural alignment of the transcatheter heart valve (THV) during transcatheter aortic valve implantation (TAVI) is seldom achieved. Orientation of the THV within the aortic root and the subsequent influence upon leaflet haemodynamic function, coronary blood flow, and ease of access to the coronary ostia are gaining significant interest. Herein, we review the incidence and clinical implications of commissural misalignment in TAVI and offer thorough descriptions of how optimal alignment can be achieved with several different contemporary THV devices.

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.

Automatic Assessment of Transcatheter Aortic Valve Implantation Results on Four-Dimensional Computed Tomography Images Using Artificial Intelligence

Transcatheter aortic valve implantation (TAVI) is a procedure to treat severe aortic stenosis. There are several clinical concerns related to potential complications after the procedure, which demand the analysis of computerized tomography (CT) scans after TAVI to assess the implant's result. This work introduces a novel, fully automatic method for the analysis of post-TAVI 4D-CT scans to characterize the prosthesis and its relationship with the patient's anatomy. The method enables measurement extraction, including prosthesis volume, center of mass, cross-sectional area (CSA) along the prosthesis axis, and CSA difference between the aortic root and prosthesis, all the variables studied throughout the cardiac cycle. The method has been implemented and evaluated with a cohort of 13 patients with five different prosthesis models, successfully extracting all the measurements from each patient in an automatic way. For Allegra patients, the mean of the obtained inner volume values ranged from 10,798.20 mm3 to 18,172.35 mm3, and CSA in the maximum diameter plane varied from 396.35 mm2 to 485.34 mm2. The implantation of this new method could provide information of the important clinical value that would contribute to the improvement of TAVI, significantly reducing the time and effort invested by clinicians in the image interpretation process.

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 6 months 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 ± 2 mm vs 5 ± 2 mm, 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 6 months 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.

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.

The impact of hypo-attenuated leaflet thickening on haemodynamic valve deterioration following transcatheter aortic valve replacement

BACKGROUND

Hypo-attenuated leaflet thickening (HALT) may occur following transcatheter aortic valve replacement (TAVR), however, it remains unclear if HALT is a predictor of haemodynamic valve deterioration (HVD).

AIM

To determine the impact of HALT on the occurrence of HVD.

METHODS

We prospectively evaluated 186 patients for the presence of HALT at a median of 6 weeks following TAVR (Interquartile-range [IQR] 4-12 weeks). HALT depth and area were measured. HVD encompassed any of the following: mean gradient ≥20 ​mmHg with an increase in gradient ≥10 ​mmHg from baseline, Doppler velocity index reduction ≥0.1 or new moderate-to-severe valvular regurgitation. Routine echocardiograms at discharge, one month and annually, were assessed by echo-cardiologists that were blinded to the HALT status.

RESULTS

LT prevalence was 17.7% (33/186). HVD was present in 8.6% (16/186) at a median follow-up of 2 years (IQR 1-3); two required valve re-intervention and five required anticoagulation. HALT was the only independent predictor of HVD on multivariate analysis (OR 33.3, 95%CI 7.4-125). Patients with HALT were more likely to develop HVD, require repeat valve intervention and have higher trans-valvular gradients at up to 3-year follow-up. Patients with HALT had a median cumulative thickness of 2.9 ​mm (IQR 1.9-4.7) and area of 64.2 ​mm² (IQR 40.9-91.6). Thresholds for HALT in predicting HVD were a cumulative depth of 2.4 ​mm (Specificity 94.1%, Sensitivity 75.0%, AUC ​= ​0.87) and cumulative area of 28 ​mm² (Specificity 92.2%, Sensitivity 81.3%, AUC ​= ​0.86).

CONCLUSION

HALT is an independent predictor of HVD, which exhibits specific depth and area thresholds to predict HVD. CT following TAVR may determine patients at risk of HVD.