Transapical transcatheter aortic valve implantation in humans: initial clinical experience

Prevalence and Risk Factors Associated With Acute Kidney Injury After Transcatheter Aortic Valve Replacement at a Tertiary Hospital in Riyadh, Saudi Arabia

BACKGROUND

Despite recent advancements in techniques, peri- and post-procedural complications still pose a significant challenge in the high-risk transcatheter aortic valve replacement (TAVR) patient population. This study aims to investigate and assess the prevalence of acute kidney injury (AKI) following TAVR, and to identify the risk factors associated with its occurrence.

METHODS

We conducted the study at King Abdulaziz Medical City, Riyadh, Saudi Arabia from January 2016 to December 2022. We extracted data from electronic medical records. We categorized and compared patients based on their diagnosis of AKI+ following TAVR, or their absence of AKI- after the procedure.

RESULTS

The study included a total of 344 patients who underwent TAVR. The mean age of the patients was 77.8 ± 8.9 years, 61.8% were male, and the average body mass index was 30.5±7.0. In terms of comorbidities, 70.8% of the patients had diabetes mellitus, 80.5% had hypertension, 8.7% had hypothyroidism, 2.0% had hematological disorders, 23.6% had congestive heart disease, 20.4% had cerebrovascular disease, 4.1% had peripheral vascular disease, 7.3% had cancer, and 34.4% had other comorbidities. The prevalence of AKI was 60 (17.50%) following the procedure. Cerebrovascular diseases showed a significant association with AKI (OR= 3.381, 95% CI, 1.65-6.91, p = 0.001). Chronic kidney disease has a significant effect on AKI (OR = 2.56, 95%CI, 1.02-6.39, p = 0.044). The creatinine level on Day 0 has a significant association with AKI (OR = 1.01, 95%CI, 1.006-1.017, p = 0.0001).

CONCLUSIONS

These findings highlight the importance of assessing and managing these risk factors (cerebrovascular diseases, chronic kidney disease, and creatinine level on Day 0) in TAVR patients to mitigate the occurrence and severity of AKI. By understanding and addressing these factors, healthcare providers can potentially improve patient outcomes and reduce the incidence of AKI-associated TAVR procedures.

Comparison of 1-year Follow-up Echocardiographic Outcomes of Sapien 3 Versus Evolut R Bioprosthetic Transcatheter Aortic Valves: A Single-center Retrospective Iranian Cohort Study

OBJECTIVE

The current study aimed to compare 1-year echocardiographic outcomes of the new generations of self-expanding (Evolut R) versus balloon-expandable (Sapien 3) bioprosthetic transcatheter aortic valves.

METHODS

In this study, gradients and flow velocities obtained from transthoracic Doppler-echocardiography were retrospectively collected from patients who underwent 2 new generations of transcatheter aortic valve implantation interventions with Sapien 3 and Evolut R valves. Patients underwent echocardiography before the procedure and at discharge, 6 months, and 1-year follow-up.

RESULTS

Of the 66 patients, 28 received Sapien 3 and 38 received Evolut R valves. Evolut R valve presented a lower mean gradient at all follow-up time points compared with Sapien 3 valves (14.4 mm Hg, 14.9 mm Hg, 15.5 mm Hg compared with 10.1 mm Hg, 11.6 mm Hg, 11.8 mm Hg, respectively; all P -values <0.001). Small valve sizes of Evolut R, including 23 and 26, had higher echocardiographic mean gradient or peak gradient at the time of discharge compared with larger valves, including sizes 29 and 34 (11.1 mm Hg and 11.2 mm Hg vs. 10.2 mm Hg, 9.1 mm Hg) and 1-year follow-up (11.0 mm Hg, 11.0 mm Hg vs. 9.9 mm Hg, 8.4 mm Hg; all P -values = 0.001). Although Sapien 3 valves demonstrated a higher peak gradient in smaller sizes at discharge (18.44 mm Hg in size 23 vs. 17.9 mm Hg, 16.5 mm Hg in size 26 and 29, respectively; P = 0.001), the peak gradients did not show a statistically significant difference in the 1-year follow-up.

CONCLUSIONS

The current study detected significantly lower mean and peak gradients in Evolut R compared with Sapien 3 at all follow-up time points. Furthermore, smaller valve sizes were associated with significantly higher gradients at all follow-ups, regardless of the valve type.

Minimally-invasive cardiac surgery: a bibliometric analysis of impact and force to identify key and facilitating advanced training

Background

The number of citations an article receives is a marker of its scientific influence within a particular specialty. This bibliometric analysis intended to recognise the top 100 cited articles in minimally-invasive cardiac surgery, to determine the fundamental subject areas that have borne considerable influence upon clinical practice and academic knowledge whilst also considering bibliometric scope. This is increasingly relevant in a continually advancing specialty and one where minimally-invasive cardiac procedures have the potential for huge benefits to patient outcomes.

Methods

The Web of Science (Clarivate Analytics) data citation index database was searched with the following terms: [Minimal* AND Invasive* AND Card* AND Surg*]. Results were limited to full text English language manuscripts and ranked by citation number. Further analysis of the top 100 cited articles was carried out according to subject, author, publication year, journal, institution and country of origin.

Results

A total of 4716 eligible manuscripts were retrieved. Of the top 100 papers, the median (range) citation number was 101 (51–414). The most cited paper by Lichtenstein et al. (Circulation 114(6):591–596, 2006) published in Circulation with 414 citations focused on transapical transcatheter aortic valve implantation as a viable alternative to aortic valve replacement with cardiopulmonary bypass in selected patients with aortic stenosis. The Annals of Thoracic Surgery published the most papers and received the most citations (n = 35; 3036 citations). The United States of America had the most publications and citations (n = 52; 5303 citations), followed by Germany (n = 27; 2598 citations). Harvard Medical School, Boston, Massachusetts, published the most papers of all institutions. Minimally-invasive cardiac surgery pertaining to valve surgery (n = 42) and coronary artery bypass surgery (n = 30) were the two most frequent topics by a large margin.

Conclusions

This work establishes a comprehensive and informative analysis of the most influential publications in minimally-invasive cardiac surgery and outlines what constitutes a citable article. Undertaking a quantitative evaluation of the top 100 papers aids in recognising the contributions of key authors and institutions as well as guiding future efforts in this field to continually improve the quality of care offered to complex cardiac patients.

30-Day Outcomes after Surgical or Transapical Aortic Valve Replacement in Symptomatic Aortic Regurgitation

Background: We aimed to analyze the short-term clinical outcomes of transapical aortic valve replacement (TA-TAVR) compared with surgical aortic valve replacement (SAVR) in symptomatic aortic regurgitation (AR) patients to draw preliminary conclusions about the advantages and disadvantages of TA-TAVR compared with SAVR and to provide evidence for future use of TA-TAVR in AR patients. Method: From September 2016 to September 2021, 69 patients undergoing TA-TAVR with J-valve implantation and 42 patients undergoing SAVR at the Second Hospital of Zhejiang University School of Medicine were analyzed for clinical data and 30-day follow-up outcomes to analyze and compare the differences in clinical endpoints between the two procedures. Results: At 30-day follow-up, there were no significant differences in mortality or neurological events between the two groups before and after the PSM. In secondary endpoints there were significant differences between the pre-match TAVR and SAVR groups, such as the incidence of paravalvular leaks (33.8% vs. 4.8%, p < 0.05), which also remained after the PSM (37.5% vs. 0, p < 0.05). In addition, the incidence of major bleeding was 7.4% in the TAVR group and 26.2% in the SAVR group before matching (p < 0.05). After matching, the statistical difference still remained. In longitudinal comparison, significant improvements in postoperative cardiac ultrasound indices and NYHA classification occurred in both groups. Conclusion: The TA-TAVR approach is safe and reliable, with similar clinical efficacy to SAVR, and has advantages in bleeding rate and speed of recovery.

Association between time-related changes in routine blood morphological parameters and renal function after transcatheter aortic valve implantation - a preliminary study

Introduction

Transcatheter aortic valve implantation (TAVI) although minimally invasive is still accompanied by changes in blood morphological parameters, some of them linked to unfavorable outcomes.

Aim

To find any association between changes in blood morphology reflecting an inflammatory response and acute kidney injury (AKI).

Material and methods

This study involved 176 consecutive transfemoral TAVI patients with a mean age of 78.4 ±7.0 years. Serum creatinine concentration (CREA) and blood morphology were analyzed in the blood samples taken before the procedure, then approximately 1, 24, 48 and 72 hours after the procedure, and lastly at the time of discharge. Post-procedural maximal or minimal values (max/min) and max/min-to-bs ratio of the laboratory parameters were also calculated.

Results

Leucocyte (WBC) and neutrophil (NEUT) counts increased significantly after the procedure whereas lymphocyte (LYMPH) counts declined markedly, reaching the highest or lowest values 24 hours after the procedure. A significant increase in neutrophil-to-lymphocyte ratio (NLR) was observed. Platelet count (PLT) dropped to a minimum at 72 hours after TAVI but at discharge did not return to the admission level. TAVI was associated with a marked increase in CREA with a peak at 48 hours after the procedure (135.7 ±75.9 μM/l). Patients with AKI (n = 65; 36.9%) presented more pronounced variations in relative changes in counts of all blood morphological parameters. A positive moderate (r = 0.412) correlation between maximal NLR and relative CREA changes was noted.

Conclusions

TAVI is associated with significant changes in blood morphological parameters that reflect an inflammatory response. They are more pronounced among subjects with post-procedural AKI.

Alternative Access for Transcatheter Aortic Valve Replacement: A Comprehensive Review

Transfemoral is the most widely used access to perform transcatheter aortic valve replacement (TAVR). However, alternative access is needed in up to 21% of patients with TAVR because of a myriad of factors. The authors provide a comprehensive review on alternative access for TAVR, discussing the relevant data and providing the pros and cons of each access route.

Transcatheter aortic valve replacement via a transsubclavian approach in a patient with severe aortic stenosis who had previously undergone kidney transplantation: A case report

RATIONALE

Although the transfemoral approach is the gold standard for transcatheter aortic valve replacement (TAVR), it is not feasible in a considerable number of patients. We report a case of successful transsubclavian TAVR (TS-TAVR) in a patient with severe aortic stenosis (AS) who was ineligible for transfemoral TAVR because she was a kidney transplant recipient.

PATIENT CONCERNS

A 72-year-old Korean woman, who had previously undergone kidney transplantation in the right iliac fossa for end-stage kidney disease, was admitted to our center with dyspnea. Upon auscultation, grade IV systolic murmurs were detected in both upper sternal borders and the left lower sternal border, suggestive of valvular heart disease.

DIAGNOSIS

Two-dimensional transthoracic echocardiography revealed heavy calcification of the aortic valve with a high peak velocity (4.54 m/s) and mean pressure gradient (48.49 mm Hg), indicative of severe AS.

INTERVENTIONS

TS-TAVR was performed by a heart team comprised of interventional cardiologists, cardiac surgeons, and anesthesiologists. A self-expandable valve prosthesis (CoreValveTM Evolut RTM, Medtronic Inc., Minneapolis, MN) was successfully deployed via the left subclavian artery.

OUTCOMES

Post-TAVR 2-dimensional transthoracic echocardiography demonstrated a well-functioning valve with mild paravalvular leakage. The peak velocity had declined from 4.54 m/s to 2.22 to 2.24 m/s, and the mean pressure gradient had declined from 48.49 to 8.57-9.61 mmHg. The patient was discharged successfully and uneventfully.

LESSONS

Because kidney transplant recipients with severe AS are considered poor candidates for transfemoral TAVR, TS-TAVR is a suitable alternative to consider.

Left Ventricular Apex: A "Minimally Invasive Motorway" for Safe Cardiovascular Procedures

Since the advent of TAVR (transcatheter aortic valve replacement), the transapical surgical approach has been affirmed as a safe and effective alternative access for patients with unsuitable peripheral arteries. With the improvement of devices for transfemoral approach and the development of other alternative accesses, the number of transapical procedures has decreased significantly worldwide. The left ventricular apex, however, has proved to be a safe and valid alternative access for various other structural heart procedures such as mitral valve repair, mitral valve-in-valve or valve-in-ring replacement, transcatheter mitral valve replacement (TMVR), transcatheter mitral paravalvular leak repair, and thoracic aorta endovascular repair (TEVAR). We review the literature and our experience of various hybrid transcatheter structural heart procedures using the transapical surgical approach and discuss pros and cons.

Alternative Access for Mechanical Circulatory Support

Femoral arterial access is the default strategy for large-bore interventional procedures, including temporary mechanical circulatory support implantation and structural heart therapies, based on superior outcomes and operator ease. In addition to patient size and comorbidities, vessel tortuosity, significant calcification, and diminutive vessel caliber all may make iliofemoral access prohibitively high risk or impossible. Given the increase of large-bore transcatheter procedures, bleeding avoidance strategies are essential and thus novel mechanisms for large-bore access have evolved. This article highlights the advantages, limitations, and practical approaches to the 2 most common percutaneous large-bore alternative access strategies: transaxillary and transcaval access.

The best way to transcatheter aortic valve implantation: From standard to new approaches

Transcatheter aortic valve implantation (TAVI) is a safe and beneficial treatment for patients with severe symptomatic aortic stenosis at high and intermediate surgical risk. The safety of the procedure continues to improve thanks to more refined procedural approaches and devices but, also and above all, to the accrual of the procedural knowledge and expertise by the operators. The diversification of the approaches and the possibility to tailor the treatment on the individual needs and anatomical features of the patients allows a rapid learning curve in the management of even complications. Indeed, there are several approaches with which TAVI can be carried out: transfemoral arterial, subclavian, transcarotid, transaortic, transaxillary, transapical, and through right anterior thoracotomy. Although transfemoral venous TAVI is less common, it has already have been carried out using caval-aortic punctures. This field is rapidly evolving, and it will be of paramount importance for interventional cardiologists and cardiothoracic surgeons to keep up to date with further developments. This review intends to give an in-depth and update overview of both conventional and innovative TAVI approaches, with the scope to highlight the relevant advantages, major disadvantages, safety aspects and techniques.

Large Left Ventricular Outflow Tract Pseudoaneurysm Closed Percutaneously From a Novel Apical Approach

An incidental finding of a large left ventricular outflow tract pseudoaneurysm in a 74-year-old man, with high surgical risk, was managed with a novel, fully percutaneous, left ventricular apical approach. The pseudoaneurysm defect and the apical puncture site were successfully closed with Amplatzer septal occluders with successful positioning, as demonstrated on cardiac computed tomography at 6 weeks follow-up. (Level of Difficulty: Intermediate.).

Transcatheter aortic valve replacement with a focus on transcarotid: a review of the current literature

Valve replacement in high-risk patients with severe aortic stenosis has undergone a huge paradigm shift in the recent years in terms of procedural details and vascular access site for patients who have poor peripheral access. Carotid artery is one of the more promising access sites which has been proven to provide a good alternative site with comparable outcomes to transfemoral approach. In this manuscript, we will provide a review of the current literature on transaortic, transapical, transaxillary and transcarotid approaches to transcatheter aortic valve replacement (TAVR) while focusing on the transcarotid approach.

The History of Transcatheter Aortic Valve Implantation (TAVI)-A Personal View Over 25 Years of development

In the early 1990s, the idea of Transcatheter Aortic Valve Implantation (TAVI) emerged from clinicians by the insight that the long-term hemodynamic and clinical results of aortic balloon valvuloplasty to treat aortic stenonosis were not satisfying. Thus, Anderson and Cribier developed the balloon-expandable and Figulla and Laborde the self-expendable TAVI systems. Sceptical views by the surgical colleagues and the industry delayed the rapid development of this disruptive new therapy until 2002, when Alain Cribier demonstrated for the first time the proof of his concept. Bulky devices and paravalvular leakages in patients treated in terms of compassionate care resulted in high mortality rates. From 2005 onwards, the treatment of patients not at highest risk using smoother devices in clinical trials could demonstrate that the technology was equivalent to surgical aortic valve replacement. The transapical access route initiated the heart team approach with the surgical colleagues, however, this access route is presently expiring due to its greater trauma. The need to treat also aortic regurgitation is addressed by the "clipping technology" of JenaValve™. Ongoing clinical trials investigate an extended indication for TAVI at an earlier stage of aortic stenosis, or in reduced ejection fraction, and just demonstrated the safety and efficiency even in low surgical risk patients.

The role of computed tomography in the planning of transcatheter aortic valve implantation: a retrospective analysis in 200 procedures

AIM

The aim of our study is to show the importance of multislice computed tomography (CT) assessment in the overall management and diagnostic framework of transcatheter aortic valve replacement (TAVI) procedure candidates.

METHODS

Between June 2015 and April 2017, 200 patients with severe aortic stenosis, not eligible for surgery, were enrolled, as defined by EuroSCORE; they were submitted to TAVI at the interventional cardiology department of the Tor Vergata Polyclinic. CT studies were performed using a 64-slice scanner.

RESULTS

The reports and datasets produced during the pre-TAVI CT evaluation were retrospectively evaluated.

DISCUSSION

In TAVI candidates, accurate aortic valve shape and dimensions evaluation is crucial for the proper deployment of the prosthetic valve and in order to reduce postprocedural complications. ECG retrospective gated cardiac CT gives the clinician three-dimensional images of the heart, with high spatial resolution and multiplanar reconstructions allowing accurate visualization of the aortic annulus and coronary ostia to be obtained, and the evaluation of arterial calcifications. Furthermore, CT can provide data on the suitability of peripheral vascular accesses. Moreover, this technique can point out the presence of clinically relevant extracardiac findings. Therefore, CT evaluation assures a safe, reliable and prognostically relevant method for TAVI preprocedural planning.

CONCLUSION

Our study remarks the importance of CT assessment in the overall management and diagnostic framework of TAVI candidates; the information provided is essential in order to minimize possible complications and to improve the quality of the therapeutic planning.

Transapical endovascular repair of iatrogenic type A aortic dissection

Intraoperative iatrogenic type A aortic dissection is a rare but known complication of cardiac surgery, with an incidence of 0.06% to 0.23%. Results are frequently catastrophic. The endovascular approach has made advances as an alternative treatment for aortic disease. However, the apical approach for transcatheter thoracic endovascular aortic repair is not well known. We present a 5-year follow-up of a case of iatrogenic type A aortic dissection after minimally invasive mitral valve repair successfully resolved by medical stabilization and subsequent transapical thoracic endovascular aortic repair.

Inter- and intra-observer repeatability of aortic annulus measurements on screening CT for transcatheter aortic valve replacement (TAVR): Implications for appropriate device sizing

OBJECTIVES

To investigate intra- and inter-observer repeatability of aortic annulus CT measurements for transcatheter aortic valve replacement (TAVR) by readers with different levels of experience and evaluate the impact of different multi-reader paradigms to improve prosthesis sizing.

METHODS

82 TAVR screening CTAs were evaluated twice by three raters with six (R1 = radiologist), three (R2 = 3D-laboratory technician) or zero (R3 = medical student) years of experience. Results were translated into hypothetical TAVR size recommendations. Intra- and inter-observer repeatability between single readers and three different multi-reader paradigms ([A]: two readers, [B]: three readers, or [C]: two readers + an optional third reader) were evaluated.

RESULTS

Intra-observer variability did not differ significantly (range: 50.1-67.8mm2). However, we found significant differences in mean inter-observer variance (p = 0.001). Multi-reader paradigms led to significantly increased precision (lower variability) for scenarios [B] and [C] (p = 0.03, p < 0.05). Compared to single readers, all multi-reader strategies clearly lowered the rate of discrepant device size categorization between repeated measurements (22-26% to 5-10%).

CONCLUSIONS

Aortic annulus CT measurements for TAVR are highly reproducible. Multi-reader strategies provide higher precision than evaluations from single readers with different levels of experience and could effectively be implemented with two readers and an optional third reader (Paradigm C) in a clinical setting.

Transcatheter Aortic Valve Replacement: Efficiency and Safety Improvements With Progressive Experience and Improved Technology

OBJECTIVE

Transcatheter aortic valve replacement is now commercially available for intermediate-risk, high-risk, or inoperable patients with severe aortic stenosis. In this study, we investigated change in the safety and efficiency of the transcatheter aortic valve replacement procedure at our institution and patient outcomes comparing our first 100, second 100, and last 100 patients.

METHODS

From March 2012 to June 2016, 544 patients underwent transcatheter aortic valve replacement at our center. Three hundred patients were selected for this study and were categorized in the following three groups: group A, first to 100th patient; group B, 101st to 200th patient; and group C, 444th to 544th patient. Preoperative, intraoperative, and postoperative data were collected.

RESULTS

Three hundred patients, 162 male (54%) male and 138 female (46%) with a mean ± SD age of 79.10 ± 8.93 years and mean ± SD society of thoracic surgeons' risk score of 7.47 ± 0.76 were included. Fluoroscopy time, operation time, and incision time significantly decreased form group A to group C (all P < 0.05). Mean of contrast volume was also the highest in group A and the lowest in group C (P < 0.001). Acute kidney injury rate was 26% (n = 26) in group A versus 23% (n = 23) in group B (P = 0.743), and only one patient in group C (group C vs. group B, P < 0.001). Strokes declined over time: five (5%) stroke in group A; two (2%) stroke in group B, and no patient in group C (group C vs. group B, P = 0.1, and group C vs. group A, P = 0.059). In-hospital mortality was 5% (n = 5) in group A, 4% (n = 4) in group B, and 1% in group C (P = 0.21).

CONCLUSIONS

Progressive experience and technology advances with transcatheter aortic valve replacement procedures improved operators' expertise, making the transcatheter aortic valve replacement more efficient and safer over time.

Transcatheter Mitral Valve-in-Valve Dislocation: A Rescue Strategy

In the transcatheter aortic valve replacement era, transapical valve-in-valve mitral valve implantation is considered an alternative treatment for high-risk patients with degenerated mitral bioprosthesis. We report an unusual strategy to remedy the potentially fatal complication of the mitral prosthesis migration into the aortic arch. The dislocated prosthesis was successfully stabilized in the aortic arch with a bare aortic stent, ensuring adequate perfusion of epiaortic vessels.

Medium and long-term prognosis of transcatheter aortic valve implantation from the perspective of left ventricular diastolic function

BACKGROUND

The effects of left ventricular (LV) diastolic function are well known in cardiac surgery, but unclear in transcatheter aortic valve implantation (TAVI). The objective of this study was to exam- ine the association of preoperative LV diastolic function with medium to long-term outcomes of TAVI.

METHODS

Eighty patients who underwent TAVI were classified into grades I, II and III based on pre- operative LV diastolic function. Findings related to cardiovascular outcomes after TAVI were extracted retrospectively from clinical and echocardiographic data and relationships with diastolic function were examined.

RESULTS

The average follow-up was 529 days (interquartile range {IQR] 358-741 days). Cardiovascu- lar events occurred in 17 cases, including 6 deaths, and were significantly associated with Euro II score (p = 0.043), albumin level (p = 0.026), coronary artery disease (CAD) (p = 0.017), and diastolic func- tion (p < 0.001). The 360-day event-free rates were 89.5%, 89.5% and 37.5% for grades I, II and III (p = 0.00013). Median event-free survival (EFS) in grade III cases was 180 days. In a Cox propor- tional hazard model, LV diastolic dysfunction (hazard ratio [HR] 3.99, 95% confidence interval [CI] 1.35-11.80, p = 0.012) and low albumin (HR 4.73, 95% CI 1.42-15.80, p = 0.012) were significant independent predictors of reduced EFS.

CONCLUSIONS

Medium to long-term outcomes of TAVI were poorer in patients with deteriorated LV diastolic function, and outcomes in grade III cases were significantly worse than those in grade I and II cases. Preoperative LV diastolic function may be useful in prediction of outcomes after TAVI.

Quantitative imaging performance of frequency-tunable capacitive micromachined ultrasonic transducer array designed for intracardiac application: Phantom study

Commercially available intracardiac echo (ICE) catheters face a trade-off between viewing depth and resolution. Frequency-tunable ICE probes would offer versatility of choice between penetration or resolution imaging within a single device. In this phantom study, the imaging performance of a novel, frequency-tunable, 32-element, 1-D CMUT array integrated with front-end electronics is evaluated. Phased-array ultrasound imaging with a forward-looking CMUT probe prototype operated beyond collapse mode at voltages up to three times higher than the collapse voltage (-65 V) is demonstrated. Imaging performance as a function of bias voltage (-70 V to -160 V), transmit pulse frequency (5-25 MHz), and number of transmit pulse cycles (1-3) is quantified, based on which penetration, resolution, and generic imaging modes are identified. It is shown that by utilizing the concept of frequency tuning, images with different characteristics can be generated trading-off the resolution and penetration depth. The penetration mode provides imaging up to 71 mm in the tissue-mimicking phantom, axial resolution of 0.44 mm, and lateral resolution of 0.12 rad. In the resolution mode, axial resolution of 0.055 mm, lateral resolution of 0.035 rad, and penetration depth of 16 mm are measured. These results show what this CMUT array has the potential versatile characteristics needed for intracardiac imaging, despite its relatively small transducer aperture size of 2 mm × 2 mm imposed by the clinical application.

Tissue-Engineered Heart Valves: A Call for Mechanistic Studies

Heart valve disease carries a substantial risk of morbidity and mortality. Outcomes are significantly improved by valve replacement, but currently available mechanical and biological replacement valves are associated with complications of their own. Mechanical valves have a high rate of thromboembolism and require lifelong anticoagulation. Biological prosthetic valves have a much shorter lifespan, and they are prone to tearing and degradation. Both types of valves lack the capacity for growth, making them particularly problematic in pediatric patients. Tissue engineering has the potential to overcome these challenges by creating a neovalve composed of native tissue that is capable of growth and remodeling. The first tissue-engineered heart valve (TEHV) was created more than 20 years ago in an ovine model, and the technology has been advanced to clinical trials in the intervening decades. Some TEHVs have had clinical success, whereas others have failed, with structural degeneration resulting in patient deaths. The etiologies of these complications are poorly understood because much of the research in this field has been performed in large animals and humans, and, therefore, there are few studies of the mechanisms of neotissue formation. This review examines the need for a TEHV to treat pediatric patients with valve disease, the history of TEHVs, and a future that would benefit from extension of the reverse translational trend in this field to include small animal studies.

Transapical cardioscopic mitral annuloplasty: a short-term survival study in a porcine model

OBJECTIVES

The transapical approach provides concurrent surgical access to the mitral and the aortic valves, the root of the aorta and the left atrium. We previously showed the feasibility of transapical cardioscopic (TAC) surgery in a non-survival porcine model. However, reproducibility and feasibility of ring implantation using TAC have not been reported. Therefore, in this study, we hypothesized that implantation of a mitral annuloplasty ring can be feasibly and safely carried out endoscopically via the apex of the heart.

METHODS

Using a porcine model in a short-term survival study, TAC mitral annuloplasty was performed in 6 pigs via an incision over the xyphoid, under cardiopulmonary bypass and cardiac arrest. A mitral annuloplasty ring was implanted via the apex to a normal mitral annulus, using a customized set of instruments and techniques. Haemodynamics, echocardiography, cardiac computed tomography, ventriculography, electrocardiography and histopathology studies were used to evaluate the function of the mitral valve and the left ventricle, coronary system and conduction system in the perioperative period and 4 weeks later.

RESULTS

All 6 animals survived and recovered from the TAC annuloplasty procedure. Postimplantation examination showed that the mitral valve was competent, left ventricular ejection fraction was 63 ± 4%, left ventricular length was 6.2 ± 0.5 cm and left ventricular end-diastolic volume was 80 ± 10 ml, which were comparable to preoperative values. Apart from a dense scar at the apex, no significant injury was noticed on the ventricle, the chordae and the mitral leaflets. The bypass, cross-clamp and implantation times were 181 ± 55 min, 130 ± 37 min and 47 ± 6 min, respectively.

CONCLUSIONS

Despite long surgical times due to the initial learning curve, successful execution of mitral ring annuloplasty could be safely achieved using the TAC approach, via a small incision without the involvement of sternum or the right pleural cavity, thereby potentially expanding the indication to patients with high-risk full sternotomy or right thoracotomy.

Vascular approaches for transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is a rapidly evolving therapeutic modality currently available for patients with severe aortic stenosis (AS) that are unsuitable for surgery because of technical/anatomical issues or high-estimated surgical risk. Transfemoral approach is the preferred TAVI delivery route when possible. Alternative non-transfemoral access options include transaortic, trans-subclavian and transapical access. Other approaches are also feasible (transcarotid, transcaval, and antegrade aortic) but are restricted to operators and hospitals with experience. The peculiarities of each of the vascular approaches designed for TAVI delivery make it necessary to carefully assess patient's atherosclerotic load and location, arterial size and tortuosity, and presence of mural thrombus. Several clinical trials are currently ongoing and in the near future the indications for these approaches will likely be better defined and extended to a broader spectrum of TAVI candidates.

Aortic sinus flow stasis likely in valve-in-valve transcatheter aortic valve implantation

OBJECTIVE

Valve-in-valve procedures using transcatheter aortic valves are increasingly performed to treat degenerated bioprosthetic surgical aortic valves because they are less invasive than redo aortic valve replacement. The objective of this study is to quantify the changes in aortic sinus blood flow dynamics before and after a valve-in-valve procedure to gain insight into mechanisms for clinical and subclinical thrombosis of leaflets.

METHODS

A detailed description of the sinus hemodynamics for valve-in-valve implantation was performed in vitro. A Medtronic Hancock II (Medtronic Inc, Minneapolis, Minn) porcine bioprosthesis was modeled as a surgical aortic valve, and Medtronic CoreValve and Edwards Sapien (Edwards Lifesciences, Irvine, Calif) valves were used as the transcatheter aortic valves. High-resolution particle image velocimetry was used to compare the flow patterns from these 2 valves within both the left coronary and noncoronary sinuses in vitro.

RESULTS

Velocity and vorticity within the surgical valve sinuses reached peak values of 0.7 m/s and 1000 s^-1, with a 70% decrease in peak fluid shear stress near the aortic side of the leaflet in the noncoronary sinus. With the introduction of transcatheter aortic valves, peak velocity and vorticity were reduced to approximately 0.4 m/s and 550 s^-1 and 0.58 m/s and 653 s^-1 without coronary flow and 0.60 m/s and 631 s^-1 and 0.81 m/s and 669 s^-1 with coronary flow for the CoreValve and Sapien valve-in-valve implantations, respectively. Peak shear stress was approximately 38% higher along the aortic side of the coronary versus noncoronary transcatheter aortic valve leaflet.

CONCLUSIONS

Decreased flow and shear stress in valve-in-valve procedures indicate a higher risk of leaflet thrombosis secondary to flow stasis, perhaps more so in the noncoronary sinus.

Non-Cardiovascular Computed Tomography Incidental Findings in Patients Who Underwent Transaortic Valve Implantation Procedure

Background

Transcatheter aortic valve implantation (TAVI) is a new treatment option for patients with severe aortic stenosis. Pre-TAVI procedure workup includes computed tomography angiography (CTA) of the heart and aorta from aortic annulus to the iliofemoral arteries. Frequently, there are a number of incidental non-cardiac findings (INCFs) in pre-TAVI CTA. However, the frequency and clinical significance of these INCFs are unknown. The aim of our study was to investigate the prevalence of INCFs and their clinical significance.

Methods

This was a retrospective review of 67 patients who underwent dedicated pre-TAVI CTA from 2010 till 2015. Non-cardiovascular INCFs were classified according to their clinical significance into three categories. The first category includes findings that may require urgent treatment. The second category includes findings that need further follow-up. The third category includes incidental findings that require no further follow-up or recommendation.

Results

The total number of patients was 67, and the mean age was 73 ± 8 years. All patients had INCFs and the total number was 248. Of the patients, 69% had chest findings, 85% had abdominal findings, and 33% had musculoskeletal findings. Results based on categorical classification were as follows: 9%, 25%, and 66% of these 248 findings belong to the first category, the second category, and the third category, respectively.

Conclusion

Non-cardiovascular INCFs are common in pre-TAVI CTA presumably due to increased age of such specific population. These findings have variable clinical significance and some of them might require acute treatment or additional evaluation, and should be managed properly taking into consideration patient’s life expectancy and comorbidities.

Transcatheter Aortic Valve Replacement: Comprehensive Review and Present Status

Aortic stenosis is the most common valvular heart disease in the developed world. About 7% of the population over age 65 years suffers from degenerative aortic stenosis. The prognosis of patients with symptomatic severe aortic stenosis is dismal without valve replacement. Even though the American College of Cardiology recommends aortic valve replacement to treat this condition as a class I recommendation, approximately one third of these patients over the age of 75 years are not referred for surgery. Typically, this is from concern about prohibitive surgical risk associated with patient frailty, comorbidities, age, and severe left ventricular dysfunction. The advent in France of transcatheter aortic valve replacement has raised the hope in the United States for an alternative, less invasive treatment for aortic stenosis. Two recent trials-the Placement of AoRTic TraNscathetER Valve Trial Edwards SAPIEN Transcatheter Heart Valve (Partner) and the CoreValve US Pivotal-have established transcatheter aortic valve replacement as the preferred approach in patients who are at high or prohibitive surgical risk. The more recently published Partner 2 trial has shown the feasibility of transcatheter aortic valve replacement in intermediate-surgical-risk patients as well. With a profile that promises easier use and better valve performance and delivery, newer-generation valves have shown their potential for further improvement in safety profile and overall outcomes. We review the history and status of this topic.

Transcatheter heart valve crimping and the protecting effects of a polyester cuff

INTRODUCTION

Prior to deployment, the percutaneous heart valves must be crimped and loaded into sheaths of diameters that can be as low as 6mm for a 23mm diameter valve. However, as the valve leaflets are fragile, any damage caused during this crimping process may contribute to reducing its long-term durability in vivo.

MATERIAL AND METHOD

Bovine pericardium percutaneous valves were manufactured as follows. The leaflets were sutured on a nitinol frame. A polyester cuff fabric served as a buffer between the pericardium and the stent. Two valves were crimped and one valve was used as control. The valves were examined in gross observation and micro-CT scan and then the leaflets were processed for histology and analyzed in scanning electron microscopy, light microscopy and transmission electron microscopy.

RESULT

Crimping of the valves resulted in the increase thickness of the leaflets and there was no evidence of additional delamination. The heavy prints of the stents were irregularly distributed on the outflow surface in the crimped devices and were shallow and did not penetrate throughout the thickness of the leaflets. However, the wavy microscopy of collagen fiber bundles was well preserved. They were found to remain individualized without any agglutination as shown by the regular banding appearance.

CONCLUSION

Crimping of self-deployable valves per se caused only minor damages to the leaflets. However, the procedure could be refined in order to minimize areas of high pressure and swelling of the tissue that can be accompanied with flow surface disruption and increase of the hydraulic conductance. The incorporation of a polyester buffer serves to prevent the deleterious effects that may be caused if the pericardium tissue were in direct contact with the nitinol stent.

The effects of contrast media volume on acute kidney injury after transcatheter aortic valve replacement: a systematic review and meta-analysis

OBJECTIVE

The goal of this systematic review was to assess the effects of contrast media volume on transcatheter aortic valve replacement-related acute kidney injury.

METHODS

A literature search was performed using Medline, EMbase, the Cochrane Database of Systematic Reviews, and clinicaltrials.gov from the inception of these databases through December 2015. Studies that reported relative risk, odds ratio, or hazard ratio comparing the risks of acute kidney injury following transcatheter aortic valve replacement in patients who received high contrast media volume were included. Pooled risk ratio (RR) and 95% confidence intervals (95% CI) were calculated using a random-effect, generic inverse variance method.

RESULTS

Four cohort studies composed of 891 patients were included in the analyses to assess the risk of acute kidney injury after transcatheter aortic valve replacement in patients who received high contrast media volume. The pooled RR of acute kidney injury after transcatheter aortic valve replacement in patients who received a large volume of contrast media was 1.41 (95% CI, 0.87 to 2.28) compared with low contrast media volume. The meta-analysis was limited to studies using standard acute kidney injury definitions, and the pooled RR of acute kidney injury in patients who received high contrast media volume is 1.12 (95% CI, 0.78 to 1.62).

CONCLUSION

Our meta-analysis shows no significant association between contrast media volume and risk of acute kidney injury after transcatheter aortic valve replacement.

Health-related quality-of-life after transapical transcatheter aortic valve implantation

PURPOSE

Transcatheter aortic valve implantation (TA-TAVI) is a well-established treatment for aortic valve stenosis in high-risk patients and indications have been continuously expanding to also include intermediate-risk patients. However, in low-risk patients, experiences are still sparse and although clinical outcomes have been shown favorable results, HRQoL has remained unexplored. The aim of this report was to describe the long-term health-related quality-of-life (HRQoL) in low-risk patients randomized to TA-TAVI or surgical aortic valve replacement (SAVR).

METHODS

In a prospective, randomized trial, patients with aortic valve stenosis were randomized to either TA-TAVI or SAVR. TA-TAVI was performed through a mini thoracotomy with the introduction of prosthesis via the apex of the heart and antegradely advancement over the pre-dilated native valve. SAVR was performed during cardiopulmonary bypass with resection of the native valve and replacement with a prosthesis valve through a median sternotomy. Afterwards, patients were followed yearly with echocardiography and HRQoL assessment.

RESULTS

A total of 58 patients were included; 29 patients for TA-TAVI and 29 patients for SAVR. The only difference in HRQoL was found in the physical component summary after 1 year; 44 ± 9 in the TA-TAVI group compared with 36 ± 9 in the SAVR group, p = .03. There were no differences in any of the remaining timepoints in neither physical nor mental component summary, p = .19 and p = .98, respectively, and there were no differences in survival during the 5 years.

CONCLUSIONS

In low-risk patients with aortic valve stenosis undergoing TA-TAVI, no differences appeared in HRQoL compared with SAVR during a 5-year follow-up period.

Mid-term study of transcatheter aortic valve implantation in an Asian population with severe aortic stenosis: two-year Valve Academic Research Consortium-2 outcomes

INTRODUCTION

Transcatheter aortic valve implantation (TAVI) is an effective treatment for high-risk or inoperative patients with severe aortic stenosis. Given the unique characteristics of Asian populations, questions regarding mid-term outcomes in Asians undergoing TAVI have yet to be addressed. We evaluated the two-year clinical outcomes of TAVI in an Asian population using Valve Academic Research Consortium-2 definitions.

METHODS

This prospective study recruited 59 patients from a major academic medical centre in Singapore. The main outcomes were two-year survival rates, peri-procedural complications, symptom improvement, valvular function and assessment of learning curve.

RESULTS

Mean age was 76.8 years (61.0% male), mean body surface area 1.6 m² and mean logistic EuroSCORE 18.7%. Survival was 93.2%, 86.0% and 79.1% at 30 days, one year and two years, respectively. At 30 days post TAVI, the rate of stroke was 1.7%, life-threatening bleeding 5.1%, acute kidney injury 25.0%, major vascular complication 5.1%, and new permanent pacemaker implantation 6.8%. 29.3% of TAVI patients were rehospitalised (47.1% cardiovascular-related) within one year. These composite outcomes were measured: device success (93.2%); early safety (79.7%); clinical efficacy (66.1%); and time-related valve safety (84.7%). Univariate analysis found these predictors of two-year all-cause mortality: logistic EuroSCORE (hazard ratio [HR] 1.07; p < 0.001); baseline estimated glomerular filtration rate (HR 0.97; p = 0.048); and acute kidney injury (HR 5.33; p = 0.022). Multivariate analysis identified non-transfemoral TAVI as a predictor of cardiovascular-related two-year mortality (HR 14.64; p = 0.008).

CONCLUSION

Despite the unique clinical differences in Asian populations, this registry demonstrated favourable mid-term clinical and safety outcomes in Asians undergoing TAVI.

Can finite element models of ballooning procedures yield mechanical response of the cardiovascular site to overexpansion?

Patient-specific numerical models could aid the decision-making process for percutaneous valve selection; in order to be fully informative, they should include patient-specific data of both anatomy and mechanics of the implantation site. This information can be derived from routine clinical imaging during the cardiac cycle, but data on the implantation site mechanical response to device expansion are not routinely available.

We aim to derive the implantation site response to overexpansion by monitoring pressure/dimensional changes during balloon sizing procedures and by applying a reverse engineering approach using a validated computational balloon model. This study presents the proof of concept for such computational framework tested in-vitro. A finite element (FE) model of a PTS-X405 sizing balloon (NuMed, Inc., USA) was created and validated against bench tests carried out on an ad hoc experimental apparatus: first on the balloon alone to replicate free expansion; second on the inflation of the balloon in a rapid prototyped cylinder with material deemed suitable for replicating pulmonary arteries in order to validate balloon/implantation site interaction algorithm.

Finally, the balloon was inflated inside a compliant rapid prototyped patient-specific right ventricular outflow tract to test the validity of the approach. The corresponding FE simulation was set up to iteratively infer the mechanical response of the anatomical model. The test in this simplified condition confirmed the feasibility of the proposed approach and the potential for this methodology to provide patient-specific information on mechanical response of the implantation site when overexpanded, ultimately for more realistic computational simulations in patient-specific settings.

The use of imaging in new transcatheter interventions: an EACVI review paper

Transcatheter therapies for the treatment of valve heart diseases have expanded dramatically over the last years. The new developments and improvements in devices and techniques, along with the increasing expertise of operators, have turned the catheter-based approaches for valvular disease into an established treatment option. Various imaging techniques are used during these procedures, but echocardiography plays an essential role during patient selection, intra-procedural monitoring, and post-procedure follow-up. The echocardiographic assessment of patients undergoing transcatheter interventions places demands on echocardiographers that differ from those of the routine evaluation of patients with valve disease, and there is a need for specific expertise for those working in the cath lab. In the context of the current rapid developments and growing use of transcatheter valve therapies, this document intends to update the previous recommendations and address new advancements in imaging, particularly for those involved in any stage of the treatment of patients with valvular heart diseases.

Impact of transfemoral versus transapical access on mortality among patients with severe aortic stenosis undergoing transcatheter aortic valve replacement

OBJECTIVE

To compare early and late mortality of transfemoral (TF) and transapical (TA) transcatheter aortic valve replacement (TAVR) patients and assess predictors for mortality.

BACKGROUND

Studies have shown conflicting results regarding impact of access on outcome in severe aortic stenosis (AS) patients undergoing TAVR.

METHODS

AS patients undergoing TAVR between May 2007-December 2014 were included. Baseline demographic, clinical, and imaging parameters were compared according to access, and landmark analysis models were generated to assess outcomes and associated factors.

RESULTS

Among 648 severe AS patients undergoing TAVR, TF was used in 516 and TA in 132. Baseline characteristics between groups demonstrated lower body mass index, higher STS score, and rate of peripheral vascular disease among TA patients. Procedural complications were more common in the TA group, especially major bleeding (15% vs. 6%, p<0.001) and acute kidney injury >1 (8% vs. 1.4%, p<0.001). Landmark analysis demonstrated higher cumulative mortality rates at 30days among TA than TF patients (log-rank p<0.001), with similar mortality after 30days and up to 1-year (13% in both log-rank p=0.64). In a multivariate model, TA was an independent predictor of early mortality (HR=4.55 95% CI [12.5-1.6], p=0.003) along with pulmonary artery systolic pressure>60mmHg (HR=3.08 95% CI [7.37-1.29], p=0.01) and residual aortic regurgitation severity above mild (HR=3.99 95% CI [10.2-1.56], p=0.004).

CONCLUSIONS

Patients undergoing TAVR via TA have higher adjusted early mortality and similar late mortality rates compared to TF, despite higher risk profile.

Nursing leadership of the transcatheter aortic valve implantation Heart Team: Supporting innovation, excellence, and sustainability

Transcatheter Aortic Valve Implantation (TAVI) is an innovative and resource-intensive treatment of valvular heart disease. Growing evidence and excellent outcomes are contributing to increased patient demand. The Heart Team is foundational to TAVI programs to manage the complexities of case selection and other aspects of care. The competencies and expertise of nurses are well suited to provide administrative and clinical leadership within the TAVI Heart Team to promote efficient, effective, and sustainable program development. The contributions of nursing administrative and clinical leaders exemplify the leadership roles that nurses can assume in healthcare innovation.

Transcatheter aortic valve replacement-state of the art and a glimpse to the future: 'the Tailored Approach'

Transcatheter aortic valve replacement determined a paradigm shift in the treatment of high-risk patients with severe symptomatic aortic valve stenosis. Notwithstanding the impressive results of the first-generation prostheses, a fast-paced technological evolution is taking place to overcome their limitations, in particular the vascular access damage and the paravalvular leak. Nowadays, with the availability of several different devices, the expert operator can select the right prosthesis for the specific anatomical and clinical situation. As 'One does not fit all', the 'Tailored TAVR Approach' we describe will conceivably become the future of this therapy.

Transcatheter Aortic Valve Replacement: a Kidney's Perspective

Transcatheter aortic valve replacement (TAVR) has now emerged as a viable treatment option for high-risk patients with severe aortic stenosis (AS) who are not suitable candidates for surgical aortic valve replacement (SAVR). Despite encouraging published outcomes, acute kidney injury (AKI) is common and lowers the survival of patients after TAVR. The pathogenesis of AKI after TAVR is multifactorial including TAVR specific factors such as the use of contrast agents, hypotension during rapid pacing, and embolization; preventive measures may include pre-procedural hydration, limitation of contrast dye exposure, and avoidance of intraprocedural hypotension. In recent years, the number of TAVR performed worldwide has been increasing, as well as published data on renal perspectives of TAVR including AKI, chronic kidney disease, end-stage kidney disease, and kidney transplantation. This review aims to present the current literature on the nephrology aspects of TAVR, ultimately to improve the patients' quality of care and outcomes.