Structural valve deterioration after transcatheter aortic valve implantation

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.

Managing the challenge of a small aortic annulus in patients with severe aortic stenosis

INTRODUCTION

Small aortic annulus (SAA) poses a challenge in the management of patients with severe aortic stenosis requiring aortic valve replacement - both surgical and transcatheter - since it has been associated with worse clinical outcomes.

AREAS COVERED

This review aims to comprehensively summarize the available evidence regarding the management of aortic stenosis in patients with SAA and discuss the current controversies as well as future perspectives in this field.

EXPERT OPINION

It is paramount to agree in a common definition for diagnosing and properly treating SAA patients, and for that purpose, multidetector computer tomography is essential. The results of recent trials led to the expansion of transcatheter aortic valve replacement among patients of all the surgical-risk spectrum, and the choice of treatment (transcatheter, surgical) should be based on patient comorbidities, anatomical characteristics, and patient preferences.

Long-term survival after surgical or transcatheter aortic valve replacement for low or intermediate surgical risk aortic stenosis: Comparison with general population

BACKGROUND

Long-term survival after surgery for severe aortic stenosis (AS) provides important information regarding the choice between surgical (SAVR) and transcatheter (TAVR) aortic valve replacement. This study investigated the long-term survival of AS patients with low or intermediate surgical risk who underwent SAVR or TAVR in our institution versus that of the Japanese general population.

METHODS

From 2009 to 2019, 1276 consecutive patients underwent SAVR or TAVR for severe AS. Among them, we retrospectively investigated those with low (n = 383) or intermediate (n = 137) surgical risk treated with SAVR and those with low (n = 86) or intermediate (n = 333) surgical risk treated with TAVR. Their post-intervention survival was compared with that of an age- and gender-matched Japanese general population.

RESULTS

The overall 5-year survival rate of SAVR for patients with low surgical risk (mean age, 72 ± 9 years) was not significantly different from that of the general population (90 % vs. 89 %, respectively; p = 0.58), whereas that of patients with intermediate surgical risk (77 ± 6 years) was significantly lower than that of the general population (77 % vs. 84 %, respectively; p = 0.03). After TAVR, the 5-year survival of patients with low (78 ± 8 years) or intermediate (83 ± 5 years) surgical risk was significantly lower than that of the general population (low risk, 64 % vs. 81 %, p < 0.01; intermediate risk, 66 % vs. 71 %, respectively, p = 0.01).

CONCLUSIONS

Our study demonstrated that long-term survival after SAVR for AS patients with low surgical risk was as good as that of the age- and gender-matched general population, while the long-term survival after SAVR for intermediate-risk or TAVR for low- or intermediate-risk patients was lower than that of the general population. These findings suggest that SAVR is an appropriate option for AS patients with low surgical risk and good life expectancy, especially in Japan, where the life expectancy is the longest worldwide.

Multimodality Imaging in Valvular Structural Interventions

Structural valvular interventions have skyrocketed in the past decade with new devices becoming available and indications for patients who would previously have been deemed inoperable. Furthermore, while echocardiography is the main imaging tool and the first line for patient screening, cardiac magnetic resonance and CT are now essential tools in pre-planning and post-procedural follow-up. This review aims to address imaging modalities and their scope in aortic, mitral and tricuspid structural valvular interventions, including multimodality imaging. Pulmonary valve procedures, which are mostly carried out in patients with congenital problems, are discussed. This article presents a guide on individualised imaging approcahes on each of the available interventional procedures.

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.

Dialdehyde pectin-crosslinked and hirudin-loaded decellularized porcine pericardium with improved matrix stability, enhanced anti-calcification and anticoagulant for bioprosthetic heart valves

To conveniently and effectively cure heart valve diseases or defects, combined with transcatheter valve technology, bioprosthetic heart valves (BHVs) originated from the decellularized porcine pericardium (D-PP) have been broadly used in clinics. Unfortunately, most clinically available BHVs crosslinked with glutaraldehyde (GA) were challenged in their long-term tolerance, degenerative structural changes, and even failure, owing to the synergistic impact of multitudinous elements (cytotoxicity, calcification, immune responses, etc.). In this work, dialdehyde pectin (AP) was prepared by oxidizing the o-dihydroxy of pectin with sodium periodate. Hereafter, the AP-fixed PP model was obtained by crosslinking D-PP with AP with high aldehyde content (6.85 mmol g^-1), for acquiring excellent mechanical properties and outstanding biocompatibility. To further improve the hemocompatibility of the AP-fixed PP, a natural and specific inhibitor of thrombin (hirudin) was introduced to achieve surface modification of the AP-fixed PP. The feasibility of crosslinking and functionalizing AP-fixed PP, which was a potential leaflet material of BHVs, was exhaustively and systematically evaluated. In vitro studies found that hirudin-loaded and AP-fixed PP (AP + Hirudin-PP) had synchronously achieved effective fixation of collagen, highly effective anticoagulation, and good HUVECs-cytocompatibility. In vivo results revealed that the AP + Hirudin-PP specimens recruited the minimum immune cells in the implantation experiment, and also presented an excellent anti-calcification effect. Overall, AP + Hirudin-PP was endowed with competitive collagen stability (compared with GA-fixed PP), excellent hemocompatibility, good HUVECs-cytocompatibility, low immunogenicity and outstanding anti-calcification, suggesting that AP + Hirudin-PP might be a promising alternative to GA-fixed PP and exhibited a bright prospect in the clinical applications of BHVs.

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.

Transcatheter valve-in-valve implantation for degenerated bioprosthetic aortic and mitral valves - an update on indications, techniques, and clinical results

Introduction: Aortic and mitral bioprosthesis are the gold standard treatment to replace a pathological native valve. However, bioprostheses are prone to structural valve degeneration, resulting in limited long-term durability. During the past decade, the implantation of transcatheter stent-valves within degenerated aortic and mitral bioprostheses, (the so-called 'valve-in-valve' procedure), represents a valid alternative to redo surgery in patients with high-risk surgical profiles.Areas covered: We reviewed the clinical outcomes and the procedural details of transcatheter aortic and mitral valve-in-valve series according to current published literature and include a practical guide for valve sizing and stent-valve positioning and strategies to prevent complications.Expert opinion: In both aortic and mitral positions meticulous planning is fundamental in these procedures to avoid serious complications including patient prosthesis mismatch, coronary obstruction and left ventricular outflow tract obstruction.

Transcatheter aortic valve implantation in low-risk patients: A case of rational over exuberance. The time is not now

BACKGROUND

Review of evidence and concerns, relating to extension of transcatheter aortic valve implantation usage to low-risk patients.

METHODS

Comprehensive literature review was conducted identifying articles relating to transcatheter aortic valve implantation.

RESULTS

Transcatheter aortic valve implantation is effective in patients with aortic stenosis. Currently, long-term durability and cost-effectiveness are unproven, anticoagulation requirement undefined, permanent pacemaker implantation and paravalvular leak rates higher than following surgical aortic valve replacement.

CONCLUSIONS

Current evidence supporting transcatheter aortic valve implantation usage in low-risk patients is insufficient. Extending use now, to this large young patient population is premature, and should be delayed.

Early and mid-term results of transcatheter aortic valve implantation and valve durability assessment

This study aimed to evaluate the early and mid-term outcomes of transcatheter aortic valve implantation (TAVI) and to assess valve durability. A total of 146 consecutive patients who underwent TAVI for severe aortic stenosis between October 2013 and August 2018 were retrospectively reviewed. All patients (mean age, 84 ± 6 years; age range 53-98 years; 42 males [28.7%]) had multiple comorbidities, with a mean logistic EuroSCORE of 30.9 ± 17.4%. Eighteen patients (12.3%) were aged 90 years or over. Five in-hospital deaths (3.4%) occurred, and 36 patients (24.7%) experienced major TAVI-related complications. With the transfemoral approach, 10 patients had major vascular complications, which mostly occurred with first-generation devices (n = 9) but less commonly with new-generation low-profile devices (P = 0.0078). During a follow-up period of 580 ± 450 (11-1738) days, 29 late deaths occurred. The survival rate was 86.0%, 78.0%, and 61.7% at 1, 2, and 3 years, respectively. Multivariate Cox hazard regression analysis revealed that more-than-moderate tricuspid regurgitation was the only independent risk factor for late deaths due to any cause (hazard ratio, 3.145; 95% confidence interval, 1.129-8.762; P = 0.0283). No statistically significant differences between post-TAVI before discharge from the hospital and at 4 years after TAVI were observed with respect to aortic valve area (1.76 ± 0.49 cm² vs. 1.64 ± 0.38 cm²; P = 0.1871) and mean pressure gradient (10.0 ± 4.6 mmHg vs. 7.9 ± 3.3 mmHg; P = 0.5032). TAVI was a feasible method with acceptable early and mid-term outcomes and valve durability for at least 4 years in poor-risk patients. Further close follow-up is essential to evaluate late outcomes and valve durability.

The current diagnosis and treatment of patients with aortic valve stenosis

Aortic valve stenosis (AS) is the third most frequent cardiovascular abnormality after coronary artery disease and hypertension. A bicuspid aortic valve is the most common cause for AS until seventh decade and calcific valve degeneration is responsible thereafter. In symptomatic patients, The risk of death increases from ≤1%/year to 2%/month. An echo valve area ≤1 cm², peak transaortic velocity ≥4 m/s, mean valve gradient ≥40 mmHg and/or computerized tomography valve calcium score >2000 Agatston units (AU) for males or more than 1200 AU for females indicate severe AS. AS stages and management are discussed. Valve replacement is based on surgical risk, valve durability/hemodynamics, need for anticoagulation and patient preferences. EuroSCORE ≥20%, Society of Thoracic Surgeons Predicted Risk of Mortality ≥8% and co-morbidities indicate high surgical risk. Surgery is recommended for low-intermediate risk patients. Transcatheter aortic valve implantation is an alternative in older patients at low, intermediate, high or prohibitive risk. Transaortic valve implantation/replacement trials are summarized.

Incidence and Predictors of Structural Valve Deterioration after Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Background

Transcatheter aortic valve replacement (TAVR), widely used as an alternative therapy in patients with severe aortic stenosis, is expected to be offered to low-risk patents with a longer life expectancy. The durability of transcatheter aortic valve is becoming of increasing importance.

Method

PubMed, Embase, and Cochrane CENTRAL from the inception to March 2020 were systematically screened for studies reporting on structural valve deterioration (SVD) in TAVR patients. Incidence of SVD was diagnosed according to the latest European consensus as the primary end point. Predictors of SVD evaluated at multivariable analysis and cumulative incidence function (CIF) of SVD were the secondary end point.

Result

Twelve studies encompassing 10031 patients evaluating the incidence of SVD were included, with a follow-up between 1 and 8 years. The pooled incidence of SVD was 4.93% (95% CI, 2.75%–7.70%, I² = 96%) at 1 year and 8.97% (95% CI, 6.89%–11.29%, I² = 86%) in the long term (≥5 years). Subgroup analysis was performed to identify the valve type that may result in partial heterogeneity. SVD was more frequent in patents with a valve diameter of <26 mm (HR: 3.57, 1.47–8.69), oral anticoagulants (OAC), exposure at discharge (OR: 0.48, 0.38–0.61), or by a disease of renal dysfunction (OR 1.42, 1.03–1.96).

Conclusion

SVD represents infrequent events after TAVR in the long term (>5 years), occurring more commonly in renal dysfunction patients, with small valve diameter and without OAC exposure. There may be an underestimation of the incidence if we assume death as a competing risk.

Severe aortic stenosis in the young, with or without bicuspid valve: is transcatheter aortic valve implantation the first choice?

During the last decade, transcatheter aortic valve implantation (TAVI) has represented a valid alternative to surgical aortic valve replacement in patients with aortic stenosis and elevated surgical risk. Recent randomized clinical trials reported excellent results also for patients at low surgical risk, but in clinical practice, the mean age of the patients treated remain over 75 years, and the presence of a bicuspid aortic valve still represents an important exclusion criteria. Today, aortic valve replacement with a mechanical prosthesis remains the treatment of choice for young adults with aortic stenosis, although the desire to avoid oral anticoagulants drives more patients younger than 65 years of age towards biological prostheses. Furthermore, despite the follow-up of patients after TAVI is still limited to a few years, the opportunity of a second percutaneous treatment (TAVI-in-TAVI), extends the scope of percutaneous strategy. In the next few years, TAVI has to face many challenges to become a valid alternative to surgery in the younger patients as well.

Degeneration of Bioprosthetic Heart Valves: Update 2020

The implantation of bioprosthetic heart valves (BHVs) is increasingly becoming the treatment of choice in patients requiring heart valve replacement surgery. Unlike mechanical heart valves, BHVs are less thrombogenic and exhibit superior hemodynamic properties. However, BHVs are prone to structural valve degeneration (SVD), an unavoidable condition limiting graft durability. Mechanisms underlying SVD are incompletely understood, and early concepts suggesting the purely degenerative nature of this process are now considered oversimplified. Recent studies implicate the host immune response as a major modality of SVD pathogenesis, manifested by a combination of processes phenocopying the long‐term transplant rejection, atherosclerosis, and calcification of native aortic valves. In this review, we summarize and critically analyze relevant studies on (1) SVD triggers and pathogenesis, (2) current approaches to protect BHVs from calcification, (3) obtaining low immunogenic BHV tissue from genetically modified animals, and (4) potential strategies for SVD prevention in the clinical setting.

Transcatheter aortic valve implantation in low-risk patients: is it too early?

The median age of patients treated by transcatheter aortic valve implantation (TAVI) is falling across Europe, and low-risk patients with severe aortic stenosis (AS) represent 80% of patients with severe AS undergoing surgical aortic valve replacement (SAVR). There are few data for TAVI in low-risk patients, but there are four ongoing randomised trials of SAVR versus TAVI. The key issues relate to pacemaker implantation rates and the associated potential longer term deleterious effects, and the need to minimise vascular complications and paravalvular leak. Valve leaflet thrombosis and paucity of data on valve durability remain a concern. Given the higher incidence of bicuspid aortic valves in younger patients, outcomes of TAVI in this setting need clarification and are discussed.

Assessment of Long-Term Structural Deterioration of Transcatheter Aortic Bioprosthetic Valves Using the New European Definition

BACKGROUND

The durability of transcatheter aortic bioprosthetic valves is a crucial issue, but data are scarce, especially beyond 5 years of follow-up. We aimed to assess long-term (7 years) structural valve deterioration (SVD) and bioprosthetic valve failure of transcatheter aortic bioprosthetic valves.

METHODS AND RESULTS

Consecutive patients with at least 5-year follow-up available undergoing transcatheter aortic valve implantation from April 2002 to December 2011 in 5 French centers were included. Incidence of SVD and bioprosthetic valve failure were defined according to newly standardized criteria of the European Association of Percutaneous Cardiovascular Interventions/European Society of Cardiology/European Association for Cardio-Thoracic Surgery and reported as cumulative incidence function to account for the competing risk of death. One thousand four hundred three consecutive patients were included with a mean age of 82.6±7.5 years and with a mean logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) of 21.3±7.5%. A balloon-expandable valve was used in 83.7% of cases. Survival rates were 83.5% (95% CI, 81.4%-85.5%) and 18.6% (95% CI, 15.3%-21.8%) at 1 and 7 years, respectively. Median duration of follow-up was 3.9 years. Bioprosthetic valve failure occurred in 19 patients with a 7-year cumulative incidence of 1.9% (95% CI, 1.4%-2.4%). SVD occurred in 49 patients (moderate, n=32; severe, n=17) with a 7-year cumulative incidence of moderate and severe SVD of 7.0% (95% CI, 5.6%-8.4%) and 4.2% (95% CI, 2.9%-5.5%), respectively. Five patients had aortic valve reintervention (1.0%; 95% CI, 0.4%-1.6%) including 1 case of surgical aortic valve replacement and 4 redo-transcatheter aortic valve implantation. The incidences of SVD and bioprosthetic valve failure were not significantly different between balloon and self-expandable prostheses.

CONCLUSIONS

The long-term assessment of transcatheter aortic bioprosthetic valves durability is limited by the poor survival of our population beyond 5 years. Further studies are warranted, particularly in younger and lower-risk patients.

Epoxy Chitosan-Crosslinked Acellular Bovine Pericardium with Improved Anti-calcification and Biological Properties

Glutaraldehyde (GA) was conventionally used to crosslink bovine pericardium to prepare bioprosthetic heart valves (BHVs), which usually fail within 10 years because of valve deterioration and calcification. To overcome the high cytotoxicity and severe calcification of GA-crosslinked BHVs, a quaternary ammonium salt of epoxy chitosan (epoxy group-modified 3-chlorine-2-hydroxypropyl trimethyl chitosan, abbreviated as "eHTCC") was developed to modify the acellular bovine pericardium to substitute GA and improve its anti-calcification and biocompatible properties. Mechanical test, enzymatic stability test, blood compatibility assay, and cytocompatibility assay were used to investigate its mechanical property and biocompatibility. The anti-calcification effect of the eHTCC-modified bovine pericardium (eHTCC-BP) was assessed by in vitro assay and rat subcutaneous implantation assay. The results showed that eHTCC-BP could improve the mechanical properties and anti-enzymolysis ability of BP, as well as retain the original three-dimensional structure, compared with the uncrosslinked-BP group. Moreover, the in vivo calcification level of the eHTCC-BP group was much lower than that of the GA-BP group, which was 5.1% (2 weeks), 2.3% (4 weeks), and 0.8% (8 weeks) of the GA-BP group. In summary, this study demonstrated that eHTCC could be a potential crosslinking agent for the extracellular matrix for its favorable crosslinking effects, anti-enzymolysis, anti-calcification, and biocompatibility.

Biomarkers of aortic bioprosthetic valve structural degeneration

PURPOSE OF REVIEW

Bioprosthetic valves are now used for the majority of surgical aortic valve replacements and for all transcatheter aortic valve replacements. However, bioprostheses are subject to structural valve deterioration (SVD) and have, therefore limited durability.

RECENT FINDINGS

Clinical, imaging, and circulating biomarkers may help to predict or indicate the presence of bioprosthetic valve SVD. The most important biomarkers of SVD includes: patient-related clinical biomarkers, such as diabetes and renal failure; valve-related biomarkers, such as absence of antimineralization process and severe prosthesis-patient mismatch; imaging biomarkers: the presence of valve leaflet mineralization on multidetector computed tomography or sodium fluoride uptake on positron emission tomography; and circulating biomarkers including: increased levels of HOMA index, ApoB/ApoA-I ratio, PCSK9, Lp-PLA2, phosphocalcic product. The assessment of these biomarkers may help to enhance risk stratification for SVD following AVR and may contribute to open novel pharmacotherapeutic avenues for the prevention of SVD.

SUMMARY

SVD may affect all bioprostheses after aortic valve replacement, and is the main cause of bioprosthetic valve failure and reintervention during the follow-up. Comprehensive assessment of clinical, imaging, and circulating biomarkers associated with earlier SVD could help strengthen the follow-up in high-risk patients and provide novel pharmacologic therapeutic strategies.

Effect of stent crimping on calcification of transcatheter aortic valves

OBJECTIVES

Although many challenges related to the acute implantation of transcatheter aortic valves have been resolved, durability and early degeneration are currently the main concerns. Recent reports indicate the potential for early valve degeneration and calcification. However, only little is known about the underlying mechanisms behind the early degeneration of these valves. The goal of this study was to test whether stent crimping increases the risk for early calcification.

METHODS

Stented valves that were crimped at 18-Fr and 14-Fr catheter and uncrimped controls were exposed to a standard calcifying solution for 50 million cycles in an accelerated wear test system. Subsequently, the leaflets of the valves were imaged by microcomputed tomography (micro-CT) followed by histochemical staining and microscopic analyses to quantify calcification and other changes in the leaflets' characteristics.

RESULTS

Heavily calcified regions were found over the stent-crimped leaflets compared to uncrimped controls, particularly around the stent's struts. Micro-CT studies measured the total volume of calcification in the uncrimped valves as 77.31 ± 1.63 mm3 vs 95.32 ± 5.20 mm3 in 18-Fr and 110.01 ± 8.33 mm3 in 14-Fr stent-crimped valves, respectively. These results were congruent with the increase in leaflet thickness measured by CT scans (0.44 ± 0.07 mm in uncrimped valves vs 0.69 ± 0.15 mm and 0.75 ± 0.09 mm in 18-Fr and 14-Fr stent-crimped valves, respectively). Histological studies confirmed the micro-CT results, denoting that the percentage of calcification in uncrimped leaflets at the valve's posts was 5.34 ± 3.97 compared to 19.97 ± 6.18 and 27.64 ± 13.17 in the 18-Fr and 14-Fr stent-crimped leaflets, respectively.

CONCLUSIONS

This study concludes that stent-crimping damage is associated with a higher level of passive leaflet calcification, which may contribute to early valve degeneration.

Aortic Stenosis: Guidelines and Evidence Gaps

Current guidelines for management of adults with aortic stenosis recommend aortic valve replacement for patients with clinical consequences due to hemodynamically severe valve obstruction. However, advances in surgical and transcatheter techniques, and improved valve design have led to decreased procedural risk and improved long-term outcomes. Transcatheter aortic valve replacement (TAVR) is recommended for patients with prohibitive surgical risk and is reasonable in intermediate and high-risk patients. Recent trials demonstrated favorable short-term outcomes in patients with low surgical risk undergoing TAVR compared with surgical AVR. We review the current Guidelines recommendations and highlight key controversies in management due to evidence gaps.

Transcatheter Aortic Valve Replacement: Procedure and Outcomes

Initially, transcatheter aortic valve replacement (TAVR) was only used in patients with severe symptomatic aortic stenosis and prohibitive risk for surgical aortic valve replacement. Subsequently, TAVR was extended to patients with high and intermediate surgical risk. Recently, the results of randomized trials in low-surgical-risk patients showed superiority or noninferiority of TAVR versus surgical aortic valve replacement in this population. Procedural outcomes have been improved. Long-term durability of transcatheter heart valves remains to be confirmed. This article presents the evolution and current status of TAVR, with respect to the different types of devices and procedures as well as its outcomes.

[Prostheses used in tavi]

Since the first human implantation of a percutaneous aortic valve in 2002, tavi prosthesis didn't stop to improve their results. These improvements allowed to decrease dramatically tavi's complications and to extend the technic to patients with mid indeed low surgery risk. So tavi became the first treatment of aortic stenosis in France since a few years.

Minimalistic Approach for Transcatheter Aortic Valve Implantation (TAVI): Open Vascular Vs. Fully Percutaneous Approach

BACKGROUND

Aortic stenosis (AS) is the most common valvular heart disease in elderly people. Transcatheter aortic valve implantation (TAVI) has emerged as a revolutionary treatment for elderly patients with symptomatic severe aortic stenosis. The authors present the first experiences with transcatheter aortic valve implantation treatment in Macedonia and compare their findings in regard to differences between open vascular vs. minimalistic transfemoral TAVI approach.

METHODS

The procedure was performed in 54 patients with severe and symptomatic AS in the period from December 2014 until February 2018. All patients were deemed having high surgical risk or were denied surgery. Pre-procedural screening included detailed clinical and echocardiographic evaluation, coronary, peripheral and carotid angiography and computed tomography scan of the aortic root. A self-expandable aortic valve (Core Valve/Evolut R, Medtronic, USA) was implanted in all patients.

RESULTS

Mean patient age was 75 ± 7.2 years, 28 (52%) were female, 26 patients (48%) male. All interventions were successfully performed through right transfemoral approach with 100% implantation success. Ancillary right radial and ulnar approach was used for correct valve positioning and control. 22(40%) cases were performed under general anesthesia and open vascular access to the femoral artery. All other 32(60%) cases were performed with minimalistic approach (local anaesthesia and analgosedation of the patients, access site was closed with closure devices). Patients in the minimalistic approach group were older, with more chronic conditions as anaemia, chronic kidney disease, poor mobility and peripheral vascular disease (p<0.0001). Also 4(12.5%) patients in the minimalistic group had bicuspid valve TAVI implantation (p<0.0001). Procedural time and contrast amount spent were shorter in this group with 97± 38 vs. 121± 38.3(p<0.0001) and 287± 122 vs. 330± 115 ml, while fluoroscopy time was similar in both groups. Immediate hemodynamic improvement was obtained in all patients. Echocardiographic peak gradient decreased from 85 ± 25 to 17 ± 8 mmHg (p < 0.001) and mean pressure gradient from 49 ± 26 to 8.3 ± 4.2 mmHg, (p < 0.001). Effective valve orifice area was 1.8±0.4 cm2 after intervention. None of the patients had significant aortic regurgitation after implantation. After intervention 7(12%) patients developed a permanent heart block and required implantation of a permanent pacemaker. There was a larger Hgb drop after intervention with open vs. minimalistic approach 1,9±0.9 vs. 0.7±0,2 g/dL (p<0.0001). 3 (13% vs.0%) patients from the open vascular access group had a major bleeding complication with 2 requiring transfusion after intervention (p<0.0001). Mortality was 5.5%, 2 with open-vascular and 1 with minimalistic approach. MACCE rate that included MI, Stroke, Major bleeding and Death rate, was recorded in 5(18%) patients with open vascular approach vs. 1(3.1%) in minimalistic approach (p<0.0001). Hospital discharge was 8.7±3.1 vs. 4±3.1 days respectively (p<0.0001). All TAVI patients with minimalistic approach were discharged the following day after intervention. All discharged patients had a good neurological condition, which was assessed based on the CPC-1 (Cerebra Performance Categories Scale). After median follow up of 26 months, the survival rate was 95% with clinical improvement in all patients.

CONCLUSION

Percutaneous aortic valve implantation can be successfully conducted with high success rate and low rate of complications in patients with severe aortic stenosis. Using a less invasive approach with local anaesthesia and analgosedation is associated with shorter length of stay and a decrease in post-procedural complication rates and MACCE.

Significance of echocardiographic evaluation for transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is widely accepted as an alternative to surgical aortic valve replacement (SAVR) for the treatment of severe aortic stenosis (AS). Existing scientific evidence demonstrates that TAVI is superior to SAVR, and it is expected that indications for the clinical applications of TAVI will be expanded in the future. Echocardiography plays a key role in perioperative assessment of patients undergoing TAVI. Preprocedural echocardiographic evaluation is important to determine the severity of AS in addition to patients' anatomical suitability for TAVI. Furthermore, echocardiography is essential for intraoperative guidance, assessment of complications, postoperative evaluation, and prognostic prediction. Inaccurate echocardiographic measurements and evaluation can lead to less-than-optimal/inappropriate treatment strategies in patients with AS. Therefore, a thorough understanding of the limitations of echocardiographic evaluation is important. This review summarizes the role of echocardiographic evaluation in patients undergoing TAVI.

Long-Term Outcomes of High-Risk or Inoperable Patients Who Underwent Transcatheter Aortic Valve Implantation

Few studies have evaluated transcatheter aortic valve implantation (TAVI) beyond 5 years. We investigated long-term outcomes (≥5 years) and transcatheter heart valve (THV) performance in patients who had undergone TAVI at least 5 years previously, based on annual follow-up. We reviewed 114 consecutive patients who were of high surgical risk or inoperable and underwent TAVI for severe aortic stenosis from October 2009 to November 2013. There was no lost to follow-up, and median time to death or latest follow-up was 5.0 years (range: 0.1 to 8.5). Structural valve degeneration (SVD) was defined on transthoracic echocardiography (TTE) as follows: (1) mean pressure gradient ≥20 mm Hg with a >10 mm Hg increase from the post-TAVI baseline, and/or (2) moderate or severe transvalvular regurgitation. The mean patient age was 82.7 ± 6.4 years, and 37.7% of patients were men. Median Society of Thoracic Surgeons score was 7.6% (interquartile range 5.8 to 10.9). TTE ≥5 years was 76.1% complete (51 of 67 patients who survived ≥5 years postoperatively). The estimated cumulative survival rates at 1, 3, 5, and 7 years were 88.6%, 72.8%, 58.8%, and 45.3%, respectively. Albumin <3.5 g/dl was strongly associated with increased long-term mortality on multivariate analysis. Longitudinal TTE confirmed durable performance of THV up to 7 years in the majority of patients; however, 6 patients (5.3% of the total cohort) experienced SVD during the follow-up. In conclusion, this study demonstrated favorable long-term survival and stable THV performance after TAVI, although SVD was not rare.

Transcatheter aortic valve implantation: a new standard of care

Aortic stenosis is the most common valvular lesion requiring intervention and with an ageing population, its burden is likely to increase. Increasing comorbidity and a desire for less invasive treatment strategies has facilitated the expansion of percutaneous aortic valve therapies. Robust clinical trial data are now available to support the role of transcatheter aortic valve implantation (TAVI) in patients of prohibitive, high and now intermediate surgical risk. The introduction of a Medicare Benefits Schedule reimbursement is likely to see TAVI use grow exponentially in Australia over the next 5 years. Clinical trials evaluating low risk patients may be the final frontier to see TAVI become the standard of care for most patients with severe aortic stenosis.

Transcatheter Mitral Valve Implantation with the Medtronic Intrepid™ Transcatheter Mitral Valve Replacement System

Mitral regurgitation is the most prevalent yet undertreated valvulopathy despite its adverse prognosis. With the emergence of transcatheter mitral interventions, the potential for this huge unmet disease burden to be addressed may finally be realized. Medtronic Intrepid™ Transcatheter Mitral Valve Replacement System represents one of several novel solutions. Based on early data from the pilot study, its efficacy and clinical utility is currently being tested against the mainstay treatment of surgical mitral valve replacement in a randomized trial. While there remain significant challenges before transcatheter mitral intervention can become part of the routine treatment algorithm, the authors are optimistic that transcatheter mitral valve repair and intervention have the potential in revolutionizing the management of severe symptomatic mitral regurgitation.

Patient-prosthesis mismatch following aortic valve replacement

Patient-prosthesis mismatch (PPM) occurs when an implanted prosthetic valve is too small for the patient; severe PPM is defined as an indexed effective orifice area (iEOA) <0.65 cm2/m2 following aortic valve replacement (AVR). This review examines articles from the past 10 years addressing the prevalence, outcomes and options for prevention and treatment of PPM after AVR. Prevalence of PPM ranges from 8% to almost 80% in individual studies. PPM is thought to have an impact on mortality, mainly in patients with severe PPM, although severe PPM accounts for only 10–15% of cases. Outcomes of patients with moderate PPM are not significantly different to those without PPM. PPM is associated with higher rates of perioperative stroke and renal failure and lack of left ventricular mass regression. Predictors include female sex, older age, hypertension, diabetes, renal failure and higher surgical risk score. PPM may be a marker of comorbidity rather than a risk factor for adverse outcomes. PPM should be suspected in patients with persistent cardiac symptoms after AVR when there is high prosthetic valve velocity or gradient and a small calculated effective orifice area. After exclusion of other causes of increased transvalvular gradient, re-intervention may be considered if symptoms persist and are unresponsive to medical therapy. However, this decision needs to consider the available options to relieve PPM and whether expected benefits justify the risk of intervention. The only effective intervention is redo surgery with implantation of a larger valve and/or annular enlargement. Therefore, focus needs to be on prevention.

The Evolut R and Evolut PRO transcatheter aortic valve systems

INTRODUCTION

Transcatheter aortic valves have evolved over the last 15 years. Second- and third- generation devices have considerably improved, and a range of newer devices have also been introduced with the aim of decreasing the incidence of paravalvular leak, reducing the need for permanent pacemaker implantation and minimizing procedure- and device-related complications. Areas covered: In this review, we highlight the special features of the latest generation of self-expanding Evolut PRO (Medtronic, Minneapolis, Minnesota) transcatheter aortic valve system. A detailed literature search on the Medtronic Evolut R and Evolut PRO transcatheter aortic valves was undertaken using Ovid, PubMed and Web of Science. Expert commentary: In a single, small study, the Evolut PRO has shown significant improvement over the Evolut R in terms of reduced paravalvular leak and pacemaker implantation. Larger scaled studies are needed to ascertain the performance of the Evolut PRO.

Pre-implantation balloon-aortic valvuloplasty before transcatheter aortic valve implantation: is this still needed?

Balloon aortic valvuloplasty (BAV) has historically been recommended prior to transcatheter aortic valve implantation (TAVI). Pre-implantation BAV (pBAV) creates fractures at the level of calcified leaflets, thereby facilitating delivery of the transcatheter valve system across the diseased aortic valve and, enhances prosthesis implantation and expansion within the calcified aortic valve annulus. New device designs, lower profile delivery systems and increasing operator experience have enabled direct-TAVI (without pBAV), and its appeal amongst TAVI operators enhanced the dissemination of a direct TAVI approach across many centres. In this review, we discuss contemporary evidence that inform the debate on the need for routine pBAV for TAVI candidates and present a framework that may assist operators in selecting patients for pBAV.

Position paper of French Interventional Group (GACI) for TAVI in France in 2018

Aortic stenosis is a frequent disease in the elderly. Its prevalence is 0.4% with a sharp increase after the age of 65, and its outcome is very poor when the patient becomes symptomatic. The interventional procedure known as TAVI (trans-catheter aortic valve implantation), which was developed in France and carried out for the first time in Rouen by Prof. Alain Cribier and his team in 2002, has proven to be a valid alternative to surgical aortic valve replacement. At first, this technique was shown to be efficient in patients with contra-indications to surgical treatment or deemed to be at high surgical risk. Given the very promising outcomes achieved as a result of close heart team collaboration, appropriate patient selection, simplified procedures and reduced complication rates, transfemoral (TF) TAVI is now preferred in symptomatic intermediate risk patients>75 years old according to the latest ESC guidelines. In 2017, in France, TAVI is currently performed in 50 centers with on-site cardiac surgery. The 2016 TAVI outcomes recorded in the French national TAVI registry (France TAVI) are very encouraging and show that for 7133 patients treated (age 83.4±7 years, logistic Euroscore 14%), 87% of whom via the TF approach, cross-over to surgery was very low (0.5%) with a 3.0% in-hospital mortality rate. The substantial increase in TAVI indications and the improvement of its outcomes may in the near future call for a reconsideration of the number of high volume centers authorized to carry out this technique.