Transcatheter aortic valve implantation: where are we now?

Rupture of the ascending aorta 6 months after TAVI procedure caused by TAVI prosthesis

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is indicated for elderly patients who often have severe comorbidities and high operative risk. Despite many advantages, it carries the potential for both early and late complications. The literature reports mainly periprocedural problems. This case report describes a rare instance of ascending aortic rupture as a late complication following TAVI.

CASE PRESENTATION

An 81-year-old male with severe aortic stenosis (AS) was a non-surgical patient due to a high operative risk (EuroSCORE II 14.08%) and comorbidities, including cardiovascular problems, chronic obstructive pulmonary disease, myelodysplastic syndrome. During the TAVI procedure Medtronic CoreValve™ Evolut™ R-26 was implanted via the right femoral artery. Postoperative period elapsed without complications and the patient was discharged home. Six months later, the patient was re-admitted to the hospital on an emergency basis and transferred directly to the operating room due to ascending aortic rupture (EuroSCORE II 53.20%, GERAADA score 64.9%). Computed tomography angiography (CTA) showed aortic rupture with a multiple fresh blood reservoirs and thrombus around the ascending aorta originating from the spot where the nitinol frame of the TAVI valve was attached to the native aorta. Supracoronary excision of the ascending aorta with implantation of a vascular graft (Intergard Woven Graft 34 mm) was performed, preserving the earlier implanted TAVI valve. On the 9th day after surgery the patient's general condition deteriorated, he suffered from circulatory and respiratory insufficiency. Furthermore, a gastrointestinal bleeding with the need for gastro-, and colonoscopy and multiple blood transfusions occurred. Patient developed urosepsis and acute renal failure with the need for hemodiafiltration. Despite intensive treatment, further deterioration of the medical condition of the patient. and finally the multiple organ failure was observed. Patient died on the 50th postoperative day.

CONCLUSIONS

TAVI is a safe method of treating severe AS, especially recommended for non-surgical candidates. Rupture of the ascending aorta is a rare but serious complication of TAVI that usually occur during or shortly after the procedure. This case report highlights the importance of post-procedural monitoring for such TAVI complications, even in the late period following TAVI, and if such complications occur, taking the risk to perform a life-saving operation.

Latest Developments in Adapting Deep Learning for Assessing TAVR Procedures and Outcomes

Aortic valve defects are among the most prevalent clinical conditions. A severely damaged or non-functioning aortic valve is commonly replaced with a bioprosthetic heart valve (BHV) via the transcatheter aortic valve replacement (TAVR) procedure. Accurate pre-operative planning is crucial for a successful TAVR outcome. Assessment of computational fluid dynamics (CFD), finite element analysis (FEA), and fluid-solid interaction (FSI) analysis offer a solution that has been increasingly utilized to evaluate BHV mechanics and dynamics. However, the high computational costs and the complex operation of computational modeling hinder its application. Recent advancements in the deep learning (DL) domain can offer a real-time surrogate that can render hemodynamic parameters in a few seconds, thus guiding clinicians to select the optimal treatment option. Herein, we provide a comprehensive review of classical computational modeling approaches, medical imaging, and DL approaches for planning and outcome assessment of TAVR. Particularly, we focus on DL approaches in previous studies, highlighting the utilized datasets, deployed DL models, and achieved results. We emphasize the critical challenges and recommend several future directions for innovative researchers to tackle. Finally, an end-to-end smart DL framework is outlined for real-time assessment and recommendation of the best BHV design for TAVR. Ultimately, deploying such a framework in future studies will support clinicians in minimizing risks during TAVR therapy planning and will help in improving patient care.

Leaflet Stresses During Full Device Simulation of Crimping to 6 mm in Transcatheter Aortic Valve Implantation, TAVI

BACKGROUND

With continuing growth in transcatheter aortic valve implantation for the treatment of a failing aortic valve, there is increasing interest in prosthetic valve durability and the potential damage caused to leaflets by stress. Whilst most available research into the computational prediction of leaflet stresses using finite element analysis, FEA, has focussed on variations during dynamic loading, very little appears to have been reported for the impact of crimping, even though awareness of this effect is widespread. Potentially, this has been due to the difficulty of performing full model simulations of crimping to clinically meaningful diameters.

METHOD

A full model comprising a self-expanding frame, skirt and leaflets has been developed and crimped to a final diameter of 6 mm. A detailed description is provided of the FEA setup, emphasising the importance of the skirt definition needed to successfully crimp to this small diameter. Then, an analysis of leaflet folding and stresses is presented, particularly with respect to the differences produced between leaflet thicknesses of 0.20, 0.25 and 0.30 mm and for bioprosthetic and polymeric leaflet material models.

RESULTS

In all cases, peak stresses occurred close to the modelled suture lines joining the leaflets and the skirt and high stresses were also present along axially aligned folds in the leaflets. Stresses were lower for the polymeric leaflets.

CONCLUSION

Successful simulation of crimping requires a finely resolved skirt mesh. Leaflet stresses during crimping are dependent on leaflet thickness, material properties and the ratio of leaflet volume to the available volume inside the crimped valve.

National Trends of Outcomes in Transcatheter Aortic Valve Replacement (TAVR) Through Transapical Versus Endovascular Approach: From the National Inpatient Sample (NIS)

BACKGROUND

To evaluate the trends in complication rates following transcatheter aortic valve replacement (TAVR) procedures according to the type of vascular approach (endovascular vs. transapical) in a large US population sample.

METHODS

The National Inpatient Sample (NIS) was queried for all patients diagnosed with aortic stenosis who underwent a TAVR procedure in the United States during the years 2012-2016. Outcomes assessed were peri-procedural mortality, cardiac, and non-cardiac complications. Hospitalization outcomes were modeled using logistic regression for binary outcomes and generalized linear models for continuous outcomes.

RESULTS

There were 97,320 endovascular-TAVR patients and 11,140 transapical-TAVR patients. The mean age was 80.8 years (standard error of the mean: ± 0.1). Most patients were males (53.7%) and Caucasian (87.1%). On multivariate analysis, after adjusting for age, gender, comorbidities, as well as hospital factors, patients with the transapical approach had a higher risk for mortality and adverse outcomes. Among the endovascular-TAVR group, national trends showed a diminishing incidence of procedural mortality (incidence rate ratio [IRR] 0.77; 95% CI: 0.72-0.84, p < 0.001), stroke (IRR 0.80; 95% CI: 0.73-0.87, p < 0.001), and all secondary outcomes, but no significant change in myocardial infarction. In contrast, most transapical-TAVR related procedural complications remained unchanged over time, except for a significant decrease in stroke, acute respiratory failure and need for pacemaker insertion.

CONCLUSION

National trends show a steady increase in the number of endovascular-TAVR procedures with a concurrent decrease in procedural complications.

Transcatheter Aortic Valve Replacement versus Surgical Aortic Valve Replacement: A Review of Aortic Stenosis Management

Severe aortic stenosis (AS) affects 3.4% of the elderly over 60 years of age. It presents with exertional dyspnea, syncope, angina, and progression to irreversible congestive heart failure. Early intervention produces a better outcome in preventing the clinical deterioration of AS. The choice of intervention is transcatheter aortic valve implantation or surgical aortic valve replacement (SAVR). The decision should be made after evaluating an individual case based on its clinical features and the user’s experience with transcatheter aortic valve replacement (TAVR). We reviewed available data to illustrate the types of ASs, the background of interventions, current guidelines for TAVR, and its comparison with SAVR in terms of adverse effects.

Frequency and impact of incidental findings on computed tomography during work-up for transcatheter aortic valve implantation: single centre experience and review of the literature

OBJECTIVE

To assess the frequency and impact of incidental findings (IF) on CT during work-up for transcatheter aortic valve intervention (TAVI).

METHODS

A consecutive cohort of patients referred for consideration of TAVI who underwent a CT scan between 2009 and 2018 were studied retrospectively. CT reports were reviewed for the presence of IFs and categorised based upon their clinical significance: (a) insignificant-findings that did not require specific treatment or follow-up; (b) intermediate-findings that did not impact on the decision-making process but required follow-up; (c) significant-findings that either required urgent investigation or meant that TAVI was clinically inappropriate.

RESULTS

A total of 652 patients were included, whose median age was 82 years. One or more insignificant IF was found in 95.6% of patients. Intermediate IFs were documented in 5.4%. 91 (14%) patients had at least one significant IF. These included possible malignancy in 67 (74%). The ultimate decision to offer aortic valve intervention was only changed by the presence of an IF in 3.5% of cases.

CONCLUSION

Clinically significant IFs are detected in more than 1 in 10 of patients undergoing CT as part of a TAVI work-up, although just over half of these patients still receive aortic valve intervention.

ADVANCES IN KNOWLEDGE

This study is the largest UK cohort, which, when combined with a review of existing literature, provides a clear picture of the frequency and clinical impact of IFs found at CT for TAVI assessment.

On-pump transapical cardioscopic mitral valve replacement with cardiac arrest: short-term results in a porcine survival model

OBJECTIVES

Favourable outcomes with mitral annuloplasty have been achieved with transapical cardioscopic (TAC) surgery in a survival animal model. In addition, experimental TAC on a non-survival animal model also showed adequate access to remove the native mitral valve and implant a prosthetic valve, but the surgical procedure took a long time and lacked follow-up data. The goal of this study was to develop a clinically translatable TAC mitral valve replacement (MVR) procedure using technical and instrumental refinements to reduce the surgical time and to evaluate functional recovery and short-term durability using a survival porcine model. We hypothesized that MVR could be achieved with subannular implantation of the bioprosthesis via the TAC approach.

METHODS

TAC MVR using the Hancock II™ (Medtronic)® mitral prosthesis was performed in 6 pigs via an incision over the xiphoid process, under cardiopulmonary bypass and cardiac arrest. COR-KNOT® and minimally invasive cardiac surgery instruments were used. Haemodynamics, echocardiography, cardiac computed tomography, ventriculography and electrocardiography were used to evaluate the function of the mitral prosthesis and left ventricle, coronary system and conduction system in the perioperative period and 4 weeks later.

RESULTS

A postimplant examination showed that the mitral prosthesis was competent, without a paravalvular leak. The left ventricular ejection fraction was comparable to preoperative values (65.2 ± 4.1 vs 67.2 ± 7.9). The bypass, cross-clamp and implant times were 177.2 ± 44.2 min, 135.3 ± 47.6 min and 94.0 ± 41.2 min, respectively. The prosthesis was in a good position. The apical scar was intact and not aneurysmal 4 weeks after the implant. The valve was properly sutured to the annulus, without a postimplant paravalvular leak. All animals recovered after 1 month of follow-up with preserved ventricular function and normal wall motion.

CONCLUSIONS

We successfully managed to replace the mitral valve with a biological prosthesis via the apex with encouraging bypass and cross-clamp times. This technique may provide an alternative for a selected group of patients with diseased mitral valves who have indications for MVR and still in a high-risk redo setting with conventional sternotomy or minimally invasive cardiac surgery-MVR.