Transcatheter aortic valve implantation: the evolution of prostheses, delivery systems and approaches

Urgent versus Non-Urgent Transcatheter Aortic Valve Implantation Outcomes

INTRODUCTION

There are limited data about the outcomes of nonelective transcatheter aortic valve implantation (TAVI). Some studies suggest that these patients (pts) have worst results. Our purpose was to compare outcomes in pts submitted to urgent versus elective TAVI.

METHODS

Retrospective analysis of 298 consecutive pts submitted to TAVI between 2018 and 2021 in a single tertiary center. Baseline characteristics and outcomes were collected and compared between elective and nonelective TAVI.

RESULTS

Pts submitted to urgent TAVI (79 pts) had worse baseline characteristics, with higher EuroScore risk (9.26 vs. 5.17%, p < 0.0001), STS score (7.09 vs. 4.4%, p < 0.0001), and NT pro-natriuretic peptide B (10,168 vs. 3,241 pg/mL, p = 0.001), lower left ventricle ejection fraction (45 vs. 52%, p = 0.003), more diabetes (46.8 vs. 32.4%, p = 0.0.22), peripheral artery disease (21.5 vs. 6.8%, p < 0.0001), and poor vascular accesses (18.4 vs. 7.4%, p = 0.007). Urgent TAVI was associated with higher mortality (25.3 vs. 15.1%, p = 0.043), 30-day cardiovascular mortality (17.5 vs. 4%, p = 0.001), life-threatening bleeding (11.5 vs. 4.1%, p = 0.018), vascular complications (11.5 vs. 4.6%, p = 0.031), and longer hospital stay (28 vs. 12 days, p < 0.0001), but not with intensive care unit or post-TAVI hospital stay (5 vs. 4 days, p = 0.197 and 11 vs. 10 days, p = 0.572). When adjusted to differences in baseline characteristics, urgent TAVI was only associated with longer hospital stay (p < 0.0001).

CONCLUSION

Pts submitted to urgent TAVI have worse short-term outcomes, but this seems to be attributable to the worse baseline characteristics instead of the urgent nature of the procedure.

Outcomes and predictors of periprocedural stroke after transcatheter aortic valve implantation

BACKGROUND

Risk factors for stroke after transcatheter aortic valve implantation (TAVI) are currently incompletely understood.

PURPOSE

To identify possible predictors of early post-TAVI stroke and explore its short-term outcomes.

METHODS

Retrospective analysis of consecutive patients (pts) submitted to TAVI between 2009 and 2020 in a tertiary center. Baseline characteristics, procedural information and stroke in first 30 days after TAVI were collected. In-hospital and 12 months outcomes were analyzed.

RESULTS

A total of 512pts (56,1% female, mean age of 82 ± 6years.) were included. In the first 30 days after TAVI 19pts (3,7%) had a stroke. In univariate analysis stroke was associated with higher body mass index (29 vs 27kg/m², p=0.035), higher triglyceridemia (> 117,5mg/dL, p=0,002), lower high-density lipoprotein (< 38,5mg/dL, p=0,009) and porcelain aorta (36,8% vs 15,5%, p=0,014) and more frequent use of post-dilatation (58,8% vs 32%, p=0,021). In multivariate analysis, triglycerides > 117,5mg/dL (p=0,032, OR = 3,751) and post-dilatation (p=0,019, OR = 3,694) were the independent predictors. Stroke after TAVI was associated with longer intensive care unit stay (12 vs 4 days, p<0,001) and post-TAVI hospital stay (25 vs 10 days, p<0,0001), higher intra-hospital mortality (21,1% vs 4,3%, p=0,003), cardiovascular 30-day mortality (15,8% vs 4,1%, p=0,026) and 1-year stroke (13,2% vs 1,1%, p=0,003).

CONCLUSION

Periprocedural and 30-day stroke is a relatively uncommon but potentially devastating complication after TAVI. In this cohort, 30-day stroke rate after TAVI was 3.7%. Hypertriglyceridemia and post-dilatation were found to be the only independent risk predictors. Outcomes after stroke, including 30-day mortality, were significantly worse.

How Transcatheter Aortic Valve Implantation (TAVI) Was Born: The Struggle for a New Invention

This story is about the invention of transcatheter aortic valve implantation (TAVI), and the people who transformed it from a concept and primitive device to a breakthrough lifesaving treatment for hundreds of thousands of patients with aortic valve stenosis. It is an inspirational example of a new disruptive technology that began with an idea most dismissed. The story describes the ups and downs from idea, design, construction, animal testing, proof-of-concept, scientific publication hurdles, a patent, license agreement, cooperation with several companies, fighting in patent courts in Europe and USA and finally how multinational companies financially bypassed the inventor. It is also a story about the struggles and battles the inventor experienced when injected into a world of lawyers and patent fights. I hope my personal story and journey can provide an inspiration and word of caution for new inventors.

New Model for the Assessment of Transcatheter Aortic Valve Replacement Devices in Sheep

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is an effective therapy in treating high-risk patients suffering from aortic stenosis. Animal models used to evaluate safety and efficacy of TAVR devices prior to clinical use lack a stenotic aortic annulus, a critical impediment to long-term TAVR device evaluation. We sought to create a reproducible model of aortic stenosis using a modified aortic annuloplasty (MAA) procedure in sheep, followed by deployment and long-term evaluation of TAVR devices using this model.

METHODS

Twelve sheep underwent the MAA procedure and were recovered. Transthoracic echocardiography (TTE) was used to monitor changes in the aortic annulus in the postoperative period. At 60 days post-MAA, Test group animals were anesthetized for TAVR insertion and Control animals underwent a necropsy. Test animals were recovered following TAVR insertion and observed for a postoperative period of 140 days.

RESULTS

Twelve sheep survived the annuloplasty procedure and the 60-day recovery period. Gross examination of seven Control group animals revealed the implanted annuloplasty ring segments formed hard protrusions into the aortic annulus. Five sheep in the Test group underwent successful deployment of Abbott's experimental TAVR device without evidence of migration. Examination at 140 days post-TAVR insertion showed all devices tightly anchored within the modified aortic annulus.

CONCLUSIONS

The MAA procedure creates stenotic segments in the aortic annulus with adequate rigidity for anchorage and long-term evaluation of TAVR devices. This represents the first model that successfully mimics human aortic stenosis and provides a clinically relevant TAVR deployment platform for long-term evaluation in sheep.

Fabrication and characterization of a large medical balloon with ultra-high strength

BACKGROUND

Transcatheter aortic valve implantation (TAVI) has emerged as a promising treatment strategy for patients with severe symptomatic aortic stenosis (AS). Moreover, characteristics of Chinese patients that are different from those of patients in Western countries, such as a high prevalence of bicuspid aortic valve (BAV), severe calcification, and a small peripheral artery diameter, have been observed.

OBJECTIVE

A novel large medical balloon with ultra-high strength was fabricated through the blending modification of PA12/TR55.

METHODS

The mechanical properties, particularly puncture resistance, of large balloons were thoroughly studied, and TR55, a modified nylon pellet with good mechanical properties and excellent compatibility with PA12, was applied to modify PA12.

RESULTS

Compared with pure PA12, the fabricated PA12/TR55 balloon exhibited a higher bursting pressure, lower compliance, and higher punctures resistance while retaining good processability and excellent biocompatibility. The improved mechanical properties can be attributed to an increase in crystallinity and densification.

CONCLUSIONS

The PA12/TR55 balloon is suitable for Chinese patients with bicuspid aortic valve and severe calcification and therefore has potential for clinical application in transcatheter aortic valve implantation. Moreover, this blending modification provides a simple but efficient method of solving other problems in cardiac angioplasty or cryoablation in which mechanical reinforcement of balloons may be necessary.

Heart valve disease in elderly

The incidence of heart valve disease increases significantly with age. Degenerative abnormalities associated with severe aortic stenosis and mitral and tricuspid regurgitation are found in not less than 10% of the population aged ≥ 75 years. Surgical treatment has been considered for years to be the treatment of choice. However, it was not uncommonly associated with high perioperative morbidity and mortality due to frequent comorbidities and overall frailty conditions of these patients. Conventional risk scores such as Society of Thoracic Surgeons and European System for Cardiac Operative Risk Evaluation may underestimate the risk of surgery in elderly patients, leading to inappropriate surgical indication. On the other hand, at least 30% of patients with severe conditions are left untreated due to prohibitive surgical risk. Interventional procedures, which are in continuous development, may be actually considered for high risk patients and, as recent results suggest, also for intermediate risk patients.

Bacterial infiltration in structural heart valve disease

OBJECTIVES

The pathology of structural valvular heart disease (sVHD) ranges from basic diseases of rheumatologic origin to chronic degenerative remodeling processes after acute bacterial infections. Molecular genetic methods allow detection of the complete microbial spectrum in heart valve tissues independent of microbiological cultivation. In particular, whole-metagenome analysis is a sensitive and highly specific analytical method that allows a deeper insight into the pathogenicity of the diseases. In the present study we assessed the pathogen spectrum in heart valve tissue from 25 sVHD patients using molecular and microbiological methods.

METHODS

Twenty-five sVHD patients were selected randomly from an observational cohort study (March 2016 to January 2017). The explanted native heart valves were examined using microbiological methods and immunohistological structural analysis. In addition, the bacterial metagenome of the heart valve tissue was determined using next-generation sequencing.

RESULTS

The use of sonication as a pretreatment of valve tissue from 4 sVHD patients permitted successful detection of Clostridium difficile, Enterococcus faecalis, Staphylococcus saccharolyticus, and Staphylococcus haemolyticus using microbial cultivation. Histological staining revealed intramural localization. Metagenome analysis identified a higher rate of bacterial infiltration in 52% of cases. The pathogen spectrum included both gram-positive and gram-negative bacteria.

CONCLUSIONS

Microbiological and molecular biological studies are necessary to detect the spectrum of bacteria in a calcified heart valve. Metagenome analysis is a valid method to gain new insight into the polymicrobial pathophysiology of sVHD. Our results suggest that an undetected proportion of sVHD might be triggered by chronic inflammation or influenced by secondary bacterial infiltration.

Procedural Results and Clinical Outcomes of Transcatheter Aortic Valve Implantation in Switzerland: An Observational Cohort Study of Sapien 3 Versus Sapien XT Transcatheter Heart Valves

BACKGROUND

New generation transcatheter heart valves (THV) may improve clinical outcomes of transcatheter aortic valve implantation.

METHODS AND RESULTS

In a nationwide, prospective, multicenter cohort study (Swiss Transcatheter Aortic Valve Implantation Registry, NCT01368250), outcomes of consecutive transfemoral transcatheter aortic valve implantation patients treated with the Sapien 3 THV (S3) versus the Sapien XT THV (XT) were investigated. An overall of 153 consecutive S3 patients were compared with 445 consecutive XT patients. Postprocedural mean transprosthetic gradient (6.5±3.0 versus 7.8±6.3 mm Hg, P=0.17) did not differ between S3 and XT patients, respectively. The rate of more than mild paravalvular regurgitation (1.3% versus 5.3%, P=0.04) and of vascular (5.3% versus 16.9%, P<0.01) complications were significantly lower in S3 patients. A higher rate of new permanent pacemaker implantations was observed in patients receiving the S3 valve (17.0% versus 11.0%, P=0.01). There were no significant differences for disabling stroke (S3 1.3% versus XT 3.1%, P=0.29) and all-cause mortality (S3 3.3% versus XT 4.5%, P=0.27).

CONCLUSIONS

The use of the new generation S3 balloon-expandable THV reduced the risk of more than mild paravalvular regurgitation and vascular complications but was associated with an increased permanent pacemaker rate compared with the XT. Transcatheter aortic valve implantation using the newest generation balloon-expandable THV is associated with a low risk of stroke and favorable clinical outcomes.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01368250.

Percutaneous heart valves; past, present and future

Percutaneous heart valves provide a promising future for patients refused surgery on the grounds of significant technical challenges or high risk for complications. Since the first human intervention more than 10 years ago, over 50 different types of valves have been developed. The CoreValve and Edwards SAPIEN valves have both experienced clinical trials and the latter has gained FDA approval for implantation in patients considered inoperable. Current complications, such as major vascular bleeding and stroke, prevent these valves from being commonly deployed in patients considered operable in conventional surgery. This review focuses on the past and present achievements of these valves and highlights the design considerations required to progress development further. It is envisaged that, with continued improvement in valve design and with increased clinical and engineering experience, percutaneous heart valve replacement may one day be a viable option for lower-risk operable patients.

[Aortic stenosis in the elderly: surgery or TAVI. New European guidelines]

Ten years after the first-in-man case, TAVI is now considered as a valid treatment of aortic stenosis in European guidelines. The first step in patient evaluation is to confirm the severity of aortic stenosis and the presence of symptoms. It is of utmost importance to check the consistency between echocardiographic criteria and clinical findings. TAVI should be considered only when surgical aortic valve replacement is contraindicated or at high risk. The assessment of the operative risk relies on a multidisciplinary heart team, taking into account risk score but keeping in mind their limitations in high-risk patients. TAVI should not be considered in low- or intermediate-risk patients, except for inclusion in controlled clinical trials. The population of high-risk patients with aortic stenosis is already important and will increase in the future due to population ageing.

Transcatheter Valve Replacement: New concepts for Microsurgery inside the Heart

Objective

Transcatheter aortic valve implantation gained clinical relevance with an impressive and peerless power; however, the procedure induces unsolved complications such as paravalvular leakage, occlusion of coronary ostia, and vascular complications. The safe removal of bulky calcified valves will improve the outcome, well known through the open surgical procedure. In this article, a new stapler-based resection and implantation device as well as a new approach for valve isolation during normal heart cycle without extracorporeal circulation will be analyzed.

Methods

First, a novel stapler-based instrument for transapical aortic valve replacement [removal and implantation; stapler-based aortic valve replacement (StapAVR)] was constructed and analyzed in an aortic debris model. Artificial aortic valves (N = 20), containing fluorescent granules to simulate the calcification, were placed into an aortic model in anatomical supine position (DP) and right-sided lateral position (RP). With the StapAVR, resection before implantation was performed in a water-filled basin. Black light was used for debris visualization. The procedures have been digitally recorded and analyzed due to procedural times, and the debris amount in thoracic side branches. Second, an enhanced prototype of the pulmonary valve isolation chamber (PVIC) was analyzed in porcine in vitro (n = 10) and in vivo models (n = 1). This PVIC contains a microaxial pump (Impella; Abiomed, Aachen, Germany) in the central bypass channel. It was deployed through the right ventricular wall. Once the PVIC was in place, the pump was started before isolating the valve. The complete hemodynamic monitoring was digitally recorded.

Results

The deployment of the StapAVR in the correct position and the valve resection time took a mean (SD) of 95.8 (19) seconds in DP and 90.1 (18) seconds in RP. Fluorescent debris was found: in the left coronary artery, 22% in DP and 7% in RP; in the ascending aorta, 0% in DP and 11% in RP; in the aortic bulbous, 5% in DP and 10% in RP; in the left ventricle, 8% in DP and 14% in RP; in the brachiocephalic trunk, 4% in DP and 9% in RP; and in the descending aorta, 46% in DP and 1% in RP. Consecutive valved stent implantation was performed without complications. The PVIC deployment time in vivo was 5 minutes, replacements included. The total valve isolation time was 21 minutes, with a mean (SD) bypass flow of 2.1 (0.4) L/min. The oxygen saturation showed a median of 91% (range, 83%–97%), and the median arterial blood pressure was 69 mm Hg (systolic; range, 47–120 mm Hg) and 40mm Hg (diastolic; range, 32–56 mm Hg) without the use of inotropes or vasopressors. Electrocardiogram confirmed sinus rhythm during isolation.

Conclusions

The resection of the artificial valves followed by valved stent implantation was possible with the StapAVR. In vivo, the procedure will be carried out under rapid pacing and sudden vacuum; however, the results of this in vitro debris model underline the need for isolation or filter devices during transcatheter aortic valve implantation to avoid embolization. Secondly, the use of the pump-advanced PVIC showed stable heart function for 21 minutes under isolated pulmonary valve conditions. This time will be adequate to remove bulky calcifications and to implant a valved stent. Improvements of both prototypes are ongoing. Nevertheless, the presented concepts showed promising application possibilities in the future.

TAVR and SAVR: Current Treatment of Aortic Stenosis

Transcatheter aortic valve replacement (TAVR) was approved in the United States in late 2011, providing a critically needed alternative therapy for patients with severe aortic stenosis previously refused surgical aortic valve replacement (SAVR). Over 20,000 TAVR have been performed in patients worldwide since 2002 when Alain Cribier performed the first-in-man TAVR. This paper reviews the data from balloon expandable and self-expanding aortic stent valves as well as data comparing them with traditional surgical aortic valve replacement (SAVR). Complications using criteria established by the Valve Academic Research Consortium (VARC) are reviewed. Future challenges and possibilities are discussed and will make optimizing TAVR an important goal in the years to come.