Five-year echocardiographic follow-up after TAVI: structural and functional changes of a balloon-expandable prosthetic aortic valve

CT imaging post-TAVI: Murphy's first law in action-preparing to recognize the unexpected

Transfemoral aortic valve implantation (TAVI) has been long considered the standard of therapy for high-risk patients with severe aortic-stenosis and is now effectively employed in place of surgical aortic valve replacement also in intermediate-risk patients. The potential lasting consequences of minor complications, which might have limited impact on elderly patients, could be more noteworthy in the longer term when occurring in younger individuals. That's why a greater focus on early diagnosis, correct management, and prevention of post-procedural complications is key to achieve satisfactory results. ECG-triggered multidetector computed tomography angiography (CTA) is the mainstay imaging modality for pre-procedural planning of TAVI and is also used for post-interventional early detection of both acute and long-term complications. CTA allows detailed morphological analysis of the valve and its movement throughout the entire cardiac cycle. Moreover, stent position, coronary artery branches, and integrity of the aortic root can be precisely evaluated. Imaging reliability implies the correct technical setting of the computed tomography scan, knowledge of valve type, normal post-interventional findings, and awareness of classic and life-threatening complications after a TAVI procedure. This educational review discusses the main post-procedural complications of TAVI with a specific imaging focus, trying to clearly describe the technical aspects of CTA Imaging in post-TAVI and its clinical applications and challenges, with a final focus on future perspectives and emerging technologies. CRITICAL RELEVANCE STATEMENT: This review undertakes an analysis of the role computed tomography angiography (CTA) plays in the assessment of post-TAVI complications. Highlighting the educational issues related to the topic, empowers radiologists to refine their clinical approach, contributing to enhanced patient care. KEY POINTS: Prompt recognition of TAVI complications, ranging from value issues to death, is crucial. Adherence to recommended scanning protocols, and the optimization of tailored protocols, is essential. CTA is central in the diagnosis of TAVI complications and functions as a gatekeeper to treatment.

Fluid-structure interaction analysis of transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is a minimally invasive intervention for the treatment of severe aortic valve stenosis. The main cause of failure is the structural deterioration of the implanted prosthetic leaflets, possibly inducing a valvular re-stenosis 5-10 years after the implantation. Based solely on pre-implantation data, the aim of this work is to identify fluid-dynamics and structural indices that may predict the possible valvular deterioration, in order to assist the clinicians in the decision-making phase and in the intervention design. Patient-specific, pre-implantation geometries of the aortic root, the ascending aorta, and the native valvular calcifications were reconstructed from computed tomography images. The stent of the prosthesis was modeled as a hollow cylinder and virtually implanted in the reconstructed domain. The fluid-structure interaction between the blood flow, the stent, and the residual native tissue surrounding the prosthesis was simulated by a computational solver with suitable boundary conditions. Hemodynamical and structural indicators were analyzed for five different patients that underwent TAVI - three with prosthetic valve degeneration and two without degeneration - and the comparison of the results showed a correlation between the leaflets' structural degeneration and the wall shear stress distribution on the proximal aortic wall. This investigation represents a first step towards computational predictive analysis of TAVI degeneration, based on pre-implantation data and without requiring additional peri-operative or follow-up information. Indeed, being able to identify patients more likely to experience degeneration after TAVI may help to schedule a patient-specific timing of follow-up.

Midterm Durability and Structural Valve Degeneration of Transcatheter Aortic Valve Replacement in a Federal Facility

OBJECTIVE

Transcatheter aortic valve replacement (TAVR), previously reserved for patients of intermediate to prohibitive surgical risk, has now been expanded to patients of any surgical risk with severe aortic stenosis. Bioprostheses are prone to structural valve degeneration (SVD), a progressive and multifactorial process that limits valve durability. As the population undergoing TAVR shifts toward a lower-risk and younger profile, long-term durability is a crucial determinant for patient outcomes. Our objective was to determine the incidence and risk factors of SVD at midterm follow-up in a veteran TAVR population.

METHODS

Patients undergoing TAVR at our federal facility were retrospectively evaluated for SVD and other endpoints with standardized consensus criteria. Multivariable Cox proportional hazards analysis was performed to evaluate risk factors for mortality and SVD.

RESULTS

From 2013 to 2020, 344 patients (median age, 78 years) underwent TAVR. Survival from all-cause mortality was 91.3% at 1 year, 75.1% at 3 years, and 61.7% at 5 years. Cumulative freedom from SVD was 98.2% at 1 year, 96.5% at 3 years, and 93.7% at 5 years. All 13 patients with SVD met hemodynamic criteria, and 1 required intervention. Median time to hemodynamic SVD was 1.04 years. Independent risk factors for SVD included age (hazard ratio [HR] = 0.92, 95% confidence interval [CI]: 0.86 to 0.99) and valve size (HR = 0.19, 95% CI: 0.04 to 0.89).

CONCLUSIONS

SVD was evident at a low but detectable rate at 5-year follow-up. Further understanding of TAVR biomechanics as well as continued longer-term follow-up will be essential for informing patient-specific risk of SVD.

Computed tomography predictors of structural valve degeneration in patients undergoing transcatheter aortic valve implantation with balloon-expandable prostheses

OBJECTIVES

Computed tomography (CT) provides excellent anatomy assessment of the aortic annulus (AoA) and is utilized for pre-procedural planning of transcatheter aortic valve implantation (TAVI). We sought to investigate if geometrical characteristics of the AoA determined by CT may represent predictors of structural valve degeneration (SVD) in patients undergoing TAVI with balloon-expandable valves.

METHODS

This is a retrospective study on 124 consecutive patients (mean age: 79 ± 7 years; female: 61%) undergoing balloon-expandable TAVI prospectively enrolled in a registry. AoA maximum diameter (D_max), minimum diameter (D_min), and area were assessed using pre-procedural CT. SVD was identified during follow-up with transthoracic echocardiography documenting structural prosthetic valve abnormalities with or without hemodynamic changes.

RESULTS

The mean follow-up was 5.9 ± 1.7 years. SVD was found in 48 out of 124 patients (38%). AoA D_max, D_min, and area were significantly smaller in patients with SVD compared to patients without SVD (25.6 ± 2.2 mm vs. 27.1 ± 2.8 mm, p = 0.012; 20.5 ± 2.1 mm vs. 21.8 ± 2.1 mm, p = 0.001 and 419 ± 77 mm² vs. 467 ± 88 mm², p = 0.002, respectively). At univariable analysis, female sex, BSA, 23-mm prosthetic valve size, D_max < 27.1 mm, and a D_min < 19.9 mm were associated with SVD, whereas at multivariable analysis, only D_min < 19.9 mm (OR = 2.873, 95% CI: 1.191-6.929, p = 0.019) and female sex (OR = 2.659, 95% CI: 1.095-6.458, p = 0.031) were independent predictors of SVD.

CONCLUSIONS

Female sex and AoA D_min < 19.9 mm are associated with SVD in patients undergoing TAVI with balloon-expandable valves. When implanting large prostheses in order to avoid paraprosthetic regurgitation, caution should be observed due to the risk of excessive stretching of the AoA D_min, which may play a role in SVD.

KEY POINTS

• Long-term durability is a concern for transcatheter aortic valve bioprosthesis. • CT provides an excellent assessment of the aortic annulus's geometrical characteristics for prosthesis sizing before transcatheter aortic valve implantation (TAVI). • Female sex and a small minimum aortic annulus diameter measured with CT are independent predictors of structural valve degeneration in patients undergoing TAVI with balloon-expandable valves.

Long-Term Echocardiographic Follow-Up After Transcatheter Aortic Valve Implantation to Assess Structural Valve Deterioration and Bioprosthetic Valve Failure

BACKGROUND

Indications for transcatheter aortic valve implantation (TAVI) in aortic stenosis are expanding and the life expectancy of patients following TAVI is increasing. Determining the long-term durability of TAVI valves is therefore important. Rates of long-term (≥5 years) structural valve deterioration (SVD) vary widely and there are currently no comparable data from Australia. The aim herein was to determine the incidence of haemodynamic SVD and bioprosthetic valve failure (BVF) using recently standardised definitions in a Western Australian cohort after at least 5 years.

METHODS

This is a retrospective cohort study of consecutive patients undergoing TAVI at Royal Perth Hospital between January 2009 and January 2015. Of 211 patients, 55 survived ≥5 years and had echocardiographic data available for review. Median time to the echocardiogram was 5.9 years (max 7.8 years); 49% male, mean age 83 years.

RESULTS

Of the 55 survivors who had echocardiograms available ≥5 years after TAVI, four (9%) had moderate haemodynamic SVD and one (2%) had severe SVD and BVF.

CONCLUSIONS

Our results suggest excellent long-term durability of contemporary TAVI valves in an Australian cohort with very low incidence of SVD and BVF. These findings add confidence to the expanding applications of TAVI valves.

Early Leaflet Thickening, Durability and Bioprosthetic Valve Failure in TAVR

All bioprosthetic valves, both surgical and transcatheter, have a finite lifespan before their leaflets inevitably degenerate, leading to stenosis or regurgitation. As younger, low-risk patients receive a transcatheter aortic valve, it is expected that they will most likely outlive their bioprosthetic valve. The heterogeneity of studies regarding surgical valve durability makes the interpretation of the data challenging. Leaflet thickening is seen in transcatheter heart valves but currently there is no evidence that it leads to premature valve deterioration or clinical events. Standardized definitions of structural valve deterioration should allow for comparisons between future clinical trials to assess the durability of different transcatheter heart valves.

Evaluation of structural valve deterioration and bioprosthetic valve failure utilizing the new European consensus definition in patients undergoing TAVI with first-generation devices: Outcomes beyond 5 years from a single center in Turkey

OBJECTIVE

The long-term durability of transcatheter aortic bioprosthetic valves continues to be a major concern. Standardized criteria of the structural valve deterioration (SVD) and bioprosthetic valve failure (BVF) have recently been defined. Limited studies have evaluated the long-term durability of transcatheter aortic valve implantation (TAVI) according to these new definitions. We aim to analyze the durability of TAVI beyond 5 years and to report the frequency of SVD and BVF.

METHODS

A total of 89 patients who had undergone TAVI and had theoretically completed at least 5 years after the procedure were included. Either a Medtronic CoreValve or an Edwards SAPIEN XT valve were implanted in the patients. New standardized definitions were used to evaluate SVD and BVF.

RESULTS

The mean age of the patients was 78.70±6.95 years. SVD occured in 4 (4.5%) patients during 6 years of follow-up. Severe SVD was observed in 2 patients (2.2%), and these patients had the New York Heart Association class II symptoms. Both patients with severe SVD also met the criteria of BVF. Moderate SVD was observed in 2 patients (2.2%), and these patients had no valve-related symptoms. Of the 4 SVD cases, 2 were associated with increased mean transaortic gradients, whereas the remaining 2 cases were associated with intraprosthetic aortic regurgitation. All patients with SVD are still alive, and none of them have required aortic valve reintervention.

CONCLUSION

Although first-generation TAVI devices were used, we determined the low rate of SVD and BVF at the 6-year follow-up. It may be suggested that there is no major concern associated with TAVI even with first-generation devices regarding long-term durability.

Predicting Long-Term Mortality in TAVI Patients Using Machine Learning Techniques

Background: Whereas transcatheter aortic valve implantation (TAVI) has become the gold standard for aortic valve stenosis treatment in high-risk patients, it has recently been extended to include intermediate risk patients. However, the mortality rate at 5 years is still elevated. The aim of the present study was to develop a novel machine learning (ML) approach able to identify the best predictors of 5-year mortality after TAVI among several clinical and echocardiographic variables, which may improve the long-term prognosis. Methods: We retrospectively enrolled 471 patients undergoing TAVI. More than 80 pre-TAVI variables were collected and analyzed through different feature selection processes, which allowed for the identification of several variables with the highest predictive value of mortality. Different ML models were compared. Results: Multilayer perceptron resulted in the best performance in predicting mortality at 5 years after TAVI, with an area under the curve, positive predictive value, and sensitivity of 0.79, 0.73, and 0.71, respectively. Conclusions: We presented an ML approach for the assessment of risk factors for long-term mortality after TAVI to improve clinical prognosis. Fourteen potential predictors were identified with the organic mitral regurgitation (myxomatous or calcific degeneration of the leaflets and/or annulus) which showed the highest impact on 5 years mortality.

Aortic valve replacement in patients over 60: Real-world surgical outcomes

OBJECTIVE

With the advent of transcatheter aortic valve implantation (TAVI) has come an expectation that there will be a decline in surgical aortic valve replacement (SAVR). This has been fueled by trials comparing outcomes between TAVI and SAVR in lower-risk patients. The aim of this study was to examine outcomes following SAVR in patients over the age of 60.

MATERIALS AND METHODS

This retrospective cohort study observed 1005 patients ≥60 who underwent isolated primary SAVR from January 2015 to December 2018. The cohort was stratified by surgical risk, defined as European System for Cardiac Operative Risk Evaluation (EuroSCORE) II < 4 versus ≥4. The cohort was also divided by age (60-69, 70-79, ≥80) for additional comparisons. Outcomes included in-hospital complications and patient survival.

RESULTS

The median age and EuroSCORE II were 75 years and 1.6, respectively. The overall 30-day mortality was 1.7% and increased significantly with surgical risk (p = .007). The 30-day mortality of elective patients was 1.1%. Overall, 1- and 2-year survival rates were 94.3% and 91.7%, respectively, which significantly decreased with surgical risk (p < .001) and age (p = .002, p = .003). The rates of postoperative stroke and pacemaker implantations were 1.2% and 3.6%, respectively.

CONCLUSIONS

SAVR can be performed in patients ≥60 years old with excellent outcomes, which compare favorably with outcomes from TAVI trials, with their highly selected patient cohorts. SAVR remains a reliable, tried and tested, treatment option in these patients.

Short and long-term clinical impact of transcatheter aortic valve implantation in Portugal according to different access routes: Data from the Portuguese National Registry of TAVI

INTRODUCTION

The Portuguese National Registry of Transcatheter Aortic Valve Implantation records prospectively the characteristics and outcomes of transcatheter aortic valve implantation (TAVI) procedures in Portugal.

OBJECTIVES

To assess the 30-day and one-year outcomes of TAVI procedures in Portugal.

METHODS

We compared TAVI results according to the principal access used (transfemoral (TF) vs. non-transfemoral (non-TF)). Cumulative survival curves according to access route, other procedural and clinical variables were obtained. The Valve Academic Research Consortium-2 (VARC-2) composite endpoint of early (30-days) safety was assessed. VARC-2 predictors of 30-days and 1-year all-cause mortality were identified.

RESULTS

Between January 2007 and December 2018, 2346 consecutive patients underwent TAVI (2242 native, 104 valve-in-valve; mean age 81±7 years, 53.2% female, EuroSCORE-II - EuroS-II, 4.3%). Device success was 90.1% and numerically lower for non-TF (87.0%). Thirty-day all-cause mortality was 4.8%, with the TF route rendering a lower mortality rate (4.3% vs. 10.1%, p=0.001) and higher safety endpoint (86.4% vs. 72.6%, p<0.001). The one-year all-cause mortality rate was 11.4%, and was significantly lower for TF patients (10.5% vs. 19.4%, p<0.002). After multivariate analysis, peripheral artery disease, previous percutaneous coronary intervention, left ventricular dysfunction and NYHA class III-IV were independent predictors of 30-day all-cause mortality. At one-year follow-up, NYHA class III-IV, non-TF route and occurrence of life-threatening bleeding predicted mortality. Kaplan-Meier survival analysis of the first year of follow-up shows decreased survival for patients with an EuroS-II>5% (p<0.001) and who underwent non-TF TAVI (p<0.001).

CONCLUSION

Data from our national real-world registry showed that TAVI was safe and effective. The use of a non-transfemoral approach demonstrated safety in the short term. Long-term prognosis was, however, adversely associated with this route, with comorbidities and the baseline clinical status.

[Postacute care after transcatheter aortic valve implantation (TAVI)]

With increasing age valvular heart disease is among the most frequent diseases of the heart. Relevant valvular disease impairs not only the long-term prognosis but also physical resilience, activities of daily living and the quality of life. In cases of middle to high-grade symptomatic cardiac defects, valve replacement or valve reconstruction is still the surgical procedure of choice; however, in recent years the transcatheter percutaneous aortic valve replacement (TAVI) procedure has become more prominent for the most frequent defect, aortic valve stenosis. This article provides an overview of the aftercare and rehabilitation of patients following a TAVI intervention.

Long-term Transcatheter Aortic Valve Durability

Transcatheter aortic valve implantation (TAVI) has become the standard of care for high-risk and inoperable surgical patients and a valid alternative to surgery for low- and intermediate-risk patients with severe, symptomatic aortic stenosis. It is increasingly being used for younger, lower-risk patients, so it is important to ensure the durability for long-term transcatheter aortic valves. The lack of standard definitions of structural valve degeneration (SVD) had made comparison among studies on prosthetic valve durability problematic. The 2017 standardised definitions of SVD by the European Association of Percutaneous Cardiovascular Intervention), the European Society of Cardiology and the European Association for Cardio-Thoracic Surgery, and the 2018 definitions by the Valve In Valve International Data group, has generated an increased uniformity in evaluations. This article examines the potential mechanisms and rates of SVD of transcatheter bioprostheses and the role of redo TAVI as a treatment option.

The year 2017 in the European Heart Journal-Cardiovascular Imaging: Part II

European Heart Journal - Cardiovascular Imaging was launched in 2012 as a multimodality cardiovascular imaging journal. It has gained an impressive impact factor of 8.366 during its first 5 years and is now established as one of the top 10 cardiovascular journals and has become the most important cardiovascular imaging journal in Europe. The most important studies from 2017 will be highlighted in two reports. Part I of the review will focus on studies about myocardial function and risk prediction, myocardial ischaemia, and emerging techniques in cardiovascular imaging, while Part II will focus on valvular heart disease, heart failure, cardiomyopathies, and congenital heart disease.

Valve durability after transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is a minimally invasive procedure to treat severe symptomatic aortic stenosis. While the TAVI procedure can be performed safely and provide excellent 5-year results, little is known about long-term durability. TAVI valves are composed of bioprosthetic leaflets are prone to deterioration, which are categorized as structural valve deterioration (SVD) and non-SVD. SVD refers to an intrinsic pathology of the leaflets or stent structure with mechanisms that include leaflet calcification, leaflet tear, stent fracture, or stent creep. Non-SVD processes include valve thrombosis, infective endocarditis and patient prosthesis mismatch. TAVI valves degenerate by similar mechanisms as bioprosthetic surgical aortic valves. Unique mechanisms that contribute to TAVI degeneration include valve crimpling, balloon expansion, stent under-expansion and valve thrombosis. The absence of a universally accepted definition of SVD poses a challenge in estimating valve durability. Traditional surgical bioprosthetic aortic valves have demonstrated excellent durability with clinically relevant SVD of 6.6% at 10-year follow up. Long-term durability of TAVI valves, however, remain poorly defined. From meta-analysis TAVI trials, SVD was estimated at 7% at 5 years. With iterative improvements in TAVI valve construction and deployment techniques, long-term durability may improve. Until long-term outcomes are better understood, TAVI should be used with caution in younger patients.

Incidence of Long-Term Structural Valve Dysfunction and Bioprosthetic Valve Failure After Transcatheter Aortic Valve Replacement

Background Long-term data on durability of currently available transcatheter heart valves are sparse. We sought to assess the incidence of long-term (8-year) structural valve dysfunction and bioprosthetic valve failure in a cohort of patients with transcatheter aortic valve replacement ( TAVR ) who reached at least 5-year follow-up. Methods and Results Consecutive patients with at least 5-year follow-up available undergoing TAVR from June 4, 2007 to March 30, 2012 were included. Structural valve dysfunction and bioprosthetic valve failure were defined according to newly standardized European Association of Percutaneous Cardiovascular Interventions/ European Society of Cardiology/European Association for Cardio-Thoracic Surgery criteria and reported as cumulative incidence function to account for the competing risk of death. A total of 288 consecutive patients with a mean age of 80.7±5.3 years and with a mean Society of Thoracic Surgery mortality score of 8.1±5.1% were analyzed. Survival rate at 8 years was 29.8%. Mean pressure gradients decreased from 53.3±15.9 mm Hg (pre- TAVR ) to 10.5±4.5 mm Hg (in-hospital post- TAVR ) ( P<0.001). There was a small, not significant, increase in the transaortic gradient throughout follow-up. Bioprosthetic valve failure was observed in a total of 11 patients (8-year cumulative incidence function: 4.51%; 95% confidence interval , 1.95%-8.76%). Severe and moderate structural valve dysfunctions were reported in 7 patients (8-year cumulative incidence function: 2.39%; 95% confidence interval, 0.77%-5.71%) and 13 patients (8-year cumulative incidence function: 5.87%; 95% confidence interval , 3.06%-9.96%), respectively. Aortic valve reintervention (redo TAVR ) was successfully performed in 2 patients (0.7%) presenting with symptomatic severe restenosis and intraprosthetic regurgitation subsequent to endocarditis. Conclusions In an aged population of patients with symptomatic severe aortic stenosis treated with first-generation bioprostheses, TAVR was associated with a survival rate of 30% but low rates of bioprosthetic valve failure and structural valve dysfunction at 8 years.

A novel echocardiographic hemodynamic index for predicting outcome of aortic stenosis patients following transcatheter aortic valve replacement

Objective

Transcatheter aortic valve replacement (TAVR) reduces left ventricular (LV) afterload and improves prognosis in aortic stenosis (AS) patients. However, LV afterload consists of both valvular and arterial loads, and the benefits of TAVR may be attenuated if the arterial load dominates. We proposed a new hemodynamic index, the Relative Valve Load (RVL), a ratio of mean gradient (MG) and valvuloarterial impedance (Zva), to describe the relative contribution of the valvular load to the global LV load, and examined whether RVL predicted patient outcome following TAVR.

Methods

A total of 258 patients with symptomatic severe AS (indexed aortic valve area (AVA)<0.6cm²/m², AR≤2+) underwent successful TAVR at the University of Ottawa Heart Institute and had clinical follow-up to 1-year post-TAVR. Pre-TAVR MG, AVA, percent stroke work loss (%SWL), Zva and RVL were measured by echocardiography. The primary endpoint was all cause mortality at 1-year post TAVR.

Results

There were 53 deaths (20.5%) at 1-year. RVL≤7.95ml/m² had a sensitivity of 60.4% and specificity of 75.1% for identifying all cause mortality at 1-year post-TAVR and provided better specificity than MG<40 mmHg, AVA>0.75cm², %SWL≤25% and Zva>5mmHg/ml/m² despite equivalent or better sensitivity. In multivariable Cox analysis, RVL≤7.95ml/m² was an independent predictor of all cause mortality (HR 3.2, CI 1.8–5.9; p<0.0001). RVL≤7.95ml/m² was predictive of all cause mortality in both low flow and normal flow severe AS.

Conclusions

RVL is a strong predictor of all-cause mortality in severe AS patients undergoing TAVR. A pre-procedural RVL≤7.95ml/m² identifies AS patients at increased risk of death despite TAVR and may assist with decision making on the benefits of TAVR.

Multimodality Imaging of the Right Ventricle

OPINION STATEMENT

Right ventricular (RV) structure and function is clinically important in a wide range of conditions. While conventional echocardiography (echo) methods are widely used, its limitations in RV assessment due its complex geometry are well recognized. New applications of traditional echo methods as well as emerging echo techniques including 3-dimensional (3D) echo and speckle tracking strain have the potential to overcome limitations of conventional echo, though widespread clinical use remains to be seen. Volumetric methods using cardiac magnetic resonance (CMR) and computed tomography (CT) provide accurate assessment of RV function without geometric assumptions. In addition, tissue characterization imaging for myocardial scar and fat using CMR and CT provides important information regarding the RV beyond structure and function alone and has clinical applications for diagnosis and prognosis in a broad range of pathologies. Limitations also exist for these two advanced modalities including availability and patient suitability for CMR and need for contrast and radiation exposure for CT. The complementary role of each modality for the RV as well as emerging evidence for the use of each imaging method in diagnosis and management of RV pathologies is outlined in this study.