Regional left ventricular function after transapical vs. transfemoral transcatheter aortic valve implantation analysed by cardiac magnetic resonance feature tracking

Artificial Intelligence in Transcatheter Aortic Valve Replacement: Its Current Role and Ongoing Challenges

Transcatheter aortic valve replacement (TAVR) has emerged as a viable alternative to surgical aortic valve replacement, as accumulating clinical evidence has demonstrated its safety and efficacy. TAVR indications have expanded beyond high-risk or inoperable patients to include intermediate and low-risk patients with severe aortic stenosis. Artificial intelligence (AI) is revolutionizing the field of cardiology, aiding in the interpretation of medical imaging and developing risk models for at-risk individuals and those with cardiac disease. This article explores the growing role of AI in TAVR procedures and assesses its potential impact, with particular focus on its ability to improve patient selection, procedural planning, post-implantation monitoring and contribute to optimized patient outcomes. In addition, current challenges and future directions in AI implementation are highlighted.

Transcatheter Mitral Valve Replacement in High-Surgical Risk Patients: A Single-Center Experience and Outcome

Background

Re-operative mitral valve (MV) replacement is a high-risk procedure, therefore, transcatheter MV replacement (TMVR) is a promising therapeutic option.

Aim

In this study, we aimed to evaluate the feasibility and safety of TMVR in patients with high surgical risk with degenerated mitral bioprostheses (TMViV), failed surgical rings (TMViR), and mitral annular calcification (TMViMAC).

Methods

This is a retrospective cohort study that enrolled patients with high surgical risk who underwent TMVR from February 2017 to September 2020. The TMVR procedure was performed using Edwards SAPIEN-3 valves through the transseptal approach.

Results

Sixty-four patients aged 62.7 ± 16.1 years with an STS score of 9.2 ± 3.7% underwent TMVR [35 (55%) TMViV, 16 (25%) TMViR, and 13 (20%) TMViMAC]. Mitral stenosis was more frequent in TMViV, mitral regurgitation was more frequent in TMViR, and combined mitral stenosis and regurgitation were more frequent in TMViMAC (P < 0.05). The MV gradient was 14.3 ± 5.3 mmHg and the MV area was 1.5±0.6 cm². The 29 mm valve was frequently used in TMViV and TMViMAC, while the 23 mm valve was frequently used in TMViR (P=0.003^∗). The procedural and fluoroscopy times were 58.7 ± 8.9 and 41.1 ± 8.2 minutes, respectively. Technical success was reported in 62 (98.4%) patients; 1 TMViR patient experienced valve embolization and salvage surgery, and 1 TMViMAC patient experienced slight valve malposition. At 3 months, 2 (3.1%) patients showed valve thrombosis (treated with anticoagulation), and 1 (1.6%) patient developed a paravalvular leak (underwent surgical MV replacement). At 6 months, 3 (4.7%) patients showed valve degeneration (underwent surgical MV replacement). Throughout follow-up, no patient exhibited mortality.

Conclusions

TMVR is a feasible and safe approach in patients with high surgical risk. TMViV and TMViR are reasonable as the first treatment approaches, and TMViMAC seems encouraging.

Prediction of cardiac events with non-contrast magnetic resonance feature tracking in patients with ischaemic cardiomyopathy

Aims

The aim of this study was to evaluate the prognostic value of feature tracking (FT) derived cardiac magnetic resonance (CMR) strain parameters of the left ventricle (LV)/right ventricle (RV) in ischaemic cardiomyopathy (ICM) patients treated with an implantable cardioverter‐defibrillator (ICD). Current guidelines suggest a LV‐ejection fraction ≤35% as major criterion for ICD implantation in ICM, but this is a poor predictor for arrhythmic events. Supplementary parameters are missing.

Methods and results

Ischaemic cardiomyopathy patients (n = 242), who underwent CMR imaging prior to primary and secondary implantation of ICD, were classified depending on EF ≤ 35% (n = 188) or >35% (n = 54). FT parameters were derived from steady‐state free precession cine views using dedicated software. The primary endpoint was a composite of cardiovascular mortality (CVM) and/or appropriate ICD therapy. There were no significant differences in FT‐function or LV‐/RV‐function parameters in patients with an EF ≤ 35% correlating to the primary endpoint. In patients with EF > 35%, standard CMR functional parameters, such as LV‐EF, did not reveal significant differences. However, significant differences in most FT parameters correlating to the primary endpoint were observed in this subgroup. LV‐GLS (left ventricular‐global longitudinal strain) and RV‐GRS (right ventricular‐global radial strain) revealed the best diagnostic performance in ROC curve analysis. The combination of LV‐GLS and RV‐GRS showed a sensitivity of 85% and a specificity of 76% for the prediction of future events.

Conclusions

The impact of FT derived measurements in the risk stratification of patients with ICM depends on LV function. The combination of LV‐GLS/RV‐GRS seems to be a predictor of cardiovascular mortality and/or appropriate ICD therapy in patients with EF > 35%.

Mitral Valve Annuloplasty Failure and Percutaneous Treatment Options

PURPOSE OF REVIEW

Mitral valve repair is a common surgical procedure for both primary and secondary mitral regurgitation. With operations performed earlier in disease progression and increased patient longevity, the need for a repeat intervention is not infrequent. With the associated risks of reoperation and patient comorbidities, percutaneous techniques for acute or delayed failure after ring annuloplasty are emerging.

RECENT FINDINGS

Current commercially available devices, used in "off-label" ways, such as the MitraClip, may be effective in repairing recurrent mitral regurgitation after annuloplasty. Similarly, a valve-in-ring transcatheter mitral valve replacement can be considered in patients at high risk for surgical reoperation. These procedures are not without risk, for example, resultant mitral stenosis in the setting of edge-to-edge repair or left ventricular outflow tract (LVOT) obstruction with valve-in-ring transcatheter mitral valve replacement. Newer devices are emerging to permit more options for this subset of patients, which include transcatheter valves that are specifically designed for the mitral position. Undoubtedly, surgical reoperation has increased risk as compared to primary operation. Though percutaneous options are evolving, use in this patient population is currently limited to "off-label" use and is also associated with procedural complexities and risk. It is prudent for cardiologists, surgeons, and anesthesiologists to weigh risks, benefits, and limitations when considering patients for surgical reoperation, percutaneous repair, or transcatheter replacement after failed mitral annuloplasty.

Challenges and opportunities in improving left ventricular remodelling and clinical outcome following surgical and trans-catheter aortic valve replacement

Over the last half century, surgical aortic valve replacement (SAVR) has evolved to offer a durable and efficient valve haemodynamically, with low procedural complications that allows favourable remodelling of left ventricular (LV) structure and function. The latter has become more challenging among elderly patients, particularly following trans-catheter aortic valve implantation (TAVI). Precise understanding of myocardial adaptation to pressure and volume overloading and its responses to valve surgery requires comprehensive assessments from aortic valve energy loss, valvular-vascular impedance to myocardial activation, force-velocity relationship, and myocardial strain. LV hypertrophy and myocardial fibrosis remains as the structural and morphological focus in this endeavour. Early intervention in asymptomatic aortic stenosis or regurgitation along with individualised management of hypertension and atrial fibrillation is likely to improve patient outcome. Physiological pacing via the His-Purkinje system for conduction abnormalities, further reduction in para-valvular aortic regurgitation along with therapy of angiotensin receptor blockade will improve patient outcome by facilitating hypertrophy regression, LV coordinate contraction, and global vascular function. TAVI leaflet thromboses require anticoagulation while impaired access to coronary ostia risks future TAVI-in-TAVI or coronary interventions. Until comparable long-term durability and the resolution of TAVI related complications become available, SAVR remains the first choice for lower risk younger patients.

[Role of magnetic resonance imaging in patients with aortic stenosis before and after replacement of the valve]

Risk stratification among patients with aortic stenosis remains inadequate, and there is a clinical need for the correct identification of high-risk patients who would benefit from aortic valve intervention before developing left ventricular decompensation. Since the publication of the results of the PARTNER study, transcatheter aortic valve implantation (TAVI) has become the method of choice for aortic valve stenosis in inoperable patients and is a real alternative to conventional surgical replacement of the aortic valve in high-risk patients. In planning TAVI and postoperative monitoring of a patient from imaging methods, the leading role is played by echocardiography and multispiral computed tomography. However, in recent years, the interest of researchers in the use of magnetic resonance imaging in this category of patients has increased. The review article examines the potential role of magnetic resonance imaging in patients with aortic stenosis before and after TAVI.

Predictors of adverse outcomes after transcatheter mitral valve replacement

Introduction: Transcatheter mitral valve replacement (TMVR) is still a recent technology with numerous unknowns but also great promises. The risk of complications reported in observational studies have limited its adoption by interventional cardiology and surgical communities. Areas covered: Some of the major setbacks of TMVR are complications related to the devices and those related to the pathway. Device-related complications include left ventricle outflow tract (LVOT) obstruction, transcatheter heart valve (THV) dislocation or embolization, thrombosis, and stroke. The transapical approach currently remains the main pathway for TMVR but is associated with high risk of major bleeding and residual apical myocardial scarring. Complication prediction and prevention seem possible. Device-related complication prediction is based on pre-operative imaging including multi-slice computed tomography with 3-dimensional reconstructions and echocardiography which allow LVOT obstruction prediction and appropriate sizing aiming at avoiding dislocation. Industry should aim at the development of transfemoral delivery systems. Nevertheless, several recent feasibility observational studies suggested acceptable safety and efficacy of transcatheter mitral valve replacement. Expert opinion: TMVR complications and transapical delivery are some of the main setbacks which need to be addressed for TMVR to be adopted for broad clinical use.

Left ventricular remodeling and function after transapical versus transfemoral transcatheter aortic valve replacement

BACKGROUND

The effect of utilizing transapical (TA) access for transcatheter aortic valve replacement (TAVR) on cardiac function has not been well studied.

AIMS

The aim of this retrospective study is to determine the direct effects of TA access for TAVR on myocardial function parameters and their correlation with 4-year survival.

METHODS

Three hundred and thirty propensity matched patients, who underwent TAVR using Sapien valve (Edwards Lifesciences Corp, Irvine, CA) between February 15, 2012 and June 17, 2016 (115 TA and 115 transfemoral [TF] routes) were studied. The pre- and 1 month post-TAVR echocardiographic features of both groups were compared. The 4-year survival in both groups was analyzed.

RESULTS

Baseline clinical characteristics, diastolic function parameters, left ventricular (LV) chamber size, and ejection fraction were similar between matched TA and TF groups. At 1 month following TAVR, there was a significant increase in stroke volume index (SVI) in both TA (mean increase 7 cm³ /m² ; P = 0.03) and TF groups (mean increase 7 cm³ /m² ; P < 0.001). Left ventricular ejection fraction (LVEF) significantly increased post TF TAVR (mean increase 2%; P = 0.008), but no significant increase was observed post TA TAVR (mean increase 1%; P = 0.27). Both groups had significant improvement in aortic valve (AV) hemodynamics post-TAVR (P < 0.001). Overall, there were no significant differences in the mean change of SVI, LVEF, or left ventricular end diastolic dimensions (LVEDDs) post TA versus TF TAVR. There was no significant difference in 4-year survival in the TF compared to TA group (49% vs 50%, P = 0.43).

CONCLUSION

Both TA and TF TAVR were equally associated with favorable changes in LV SVI and AV hemodynamics in 30 days. TA TAVR patients had similar 4 year survival to propensity matched TF TAVR; therefore, TA TAVR remains an acceptable alternative access route in patients not amenable to TF TAVR.

Transapical transcatheter aortic valve implantation in patients with a low ejection fraction

OBJECTIVES

It may be expected that patients with left ventricular dysfunction may be at greater risk of complications after transcatheter aortic valve implantation (TAVI) via transapical (TA) access compared with via transfemoral (TF) access. There is a lack of data comparing the outcomes of TAVI using TA and TF access in patients with a reduced left ventricular ejection fraction (EF).

METHODS

This is a retrospective analysis of data from a high-volume heart centre in Germany. TAVI access route assignment was based on a 'best for TF' approach, where only patients who met a strict set of criteria underwent TF-TAVI, with the remainder receiving TA-TAVI. For this analysis, patients were included if they had a pre-TAVI EF of ≤ 40%. Early mortality and late (1-year) mortality were compared through multivariate logistic regression.

RESULTS

A total of 342 patients in the registry had an EF of ≤ 40%, of which 74.9% underwent TA-TAVI and 25.1% underwent TF-TAVI. Higher proportions of the TA group presented with certain comorbidities, and their logistic EuroSCORE and Society of Thoracic Surgeons (STS) risk scores were higher than in the TF group. At 1 year, TA access was associated with greater mortality in the univariate analysis (odd ratio 2.43; 95% confidence interval 1.04-5.69). However, after multivariate adjustment, no significant differences were found in either 30-day or 1-year mortality rates.

CONCLUSIONS

The data suggest that, for patients with a reduced EF, TA-TAVI is not associated with a poorer outcome compared with TF-TAVI. Therefore, TA access should not be discounted based on the presence of left ventricular dysfunction alone.

Changes in left ventricular function in patients with aortic regurgitation 12 months after transapical transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is an established treatment for high surgical risk aortic stenosis patients; in recent years, it has also been used in patients with pure/dominant aortic regurgitation (AR). This study aimed to determine the impact of transapical TAVI on left ventricle myocardial mechanics in AR patients. Thirty AR patients (70% men; mean age, 72.8 ± 4.3 years) were enrolled. Conventional echocardiography was performed on all patients before and 12 months after TAVI. Three-dimensional speckle tracking was accomplished in 20 AR patients for the evaluation of global longitudinal strain, global circumferential strain, twist, torsion, apical rotation and basal rotation. Preoperative left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), global circumferential strain (GCS), twist, torsion and apical rotation were impaired in AR patients compared with controls. Mean left ventricular (LV) end-diastolic diameter (from 62.9 ± 7.3 to 52.0 ± 6.8 mm, p < 0.001), LV end-diastolic volume (from 199.4 ± 55.0 to 130.1 ± 48.9 mL, p < 0.001), and LV mass index (179.8 ± 52.2-134.4 ± 42.5 g/m², p = 0.001) decreased 12 months after TAVI. Interestingly, GLS (from - 17.2 ± 3.2 to - 18.9 ± 3.7, p = 0.007) and GCS (from - 23.9 ± 4.9 to - 25.7 ± 5.0, p = 0.008) improved significantly, but LVEF did not significantly improve. In terms of the rotational mechanics, twist, rotation and basal rotation remained almost unchanged, whereas apical rotation (from 7.4 ± 4.0 to 5.5 ± 3.9, p = 0.009) was significantly impaired after transapical TAVI. Our results indicate that LV function was improved in terms of myocardial deformation but worsened in terms of apical rotation 12 months after TAVI in AR patients. Three-dimensional speckle tracking echocardiography appears to be a sensitive method for detecting subtle cardiac remodeling after TAVI.

Successful Treatment of Mitral Regurgitation after Transapical Transcatheter Aortic Valve Implantation by Percutaneous Edge-to-edge Mitral Valve Repair (MitraClip®) -The First Combination Therapy Performed in Japan

A 75-year old man with a history of inferior myocardial infarction was admitted with symptoms of progressive heart failure 3 months after undergoing transapical transcatheter aortic valve implantation (TAVI). Echocardiography revealed severe mitral regurgitation (MR) caused by posterior leaflet tethering, without traumatic injury of the mitral valve or chordae. The patient was successfully treated by percutaneous edge-to-edge mitral valve repair (MitraClip^®). This case highlights the role of MitraClip^® in high-risk patients suffering from MR, and suggests that apical contractile loss or adhesion caused by apical puncture and suturing in transapical TAVI may be one of the mechanisms of worsening MR.

Per-Ventricular Insertion of Melody Valve-in-Valve in the Neoaortic Position in a Single-Ventricle Patient

Percutaneous therapies for congenital heart disease have been evolving rapidly despite limited investment from industry. The Melody transcatheter pulmonary valve (Medtronic, Inc, Minneapolis, MN USA) replacement therapy represents an important advancement in this arena. It has been approved in the United States for use in the pulmonary position, on a Humanitarian Device Exemption status. Off-label use of the Melody transcatheter pulmonary valve has extended to the mitral, pulmonary, and aortic valves, especially in previously implanted valves with prosthetic valve degeneration. The single-ventricle patient poses additional challenges. However, there exists one report in the English literature of a patient undergoing Melody transcatheter neoaortic valve replacement after the patient developed severe neoaortic regurgitation after Fontan palliation. Here, we describe a patient with hypoplastic left heart syndrome, palliated with a Norwood modified Blalock-Taussig shunt, with a progressively regurgitant quadricusp neoaortic valve who underwent bioprosthetic valve replacement. There was early prosthetic valve degeneration after a year of bioprosthesis implantation. As he was declined for transplantation, he underwent successful perventricular Melody valve-in-valve replacement.

Alternate Access for TAVI: Stay Clear of the Chest

Transcatheter aortic valve implantation (TAVI) is currently performed through an alternative access in 15% of patients. The transapical access is progressively being abandoned as a result of its invasiveness and poor outcomes. Existing data does not allow TAVI operators to favour one access over another - between transcarotid, trans-subclavian and transaortic - because all have specific strengths and weaknesses. The percutaneous trans-subclavian access might become the main surgery-free alternative access, although further research is needed regarding its safety. Moreover, the difficult learning curve might compromise its adoption. The transcaval access is at an experimental stage and requires the development of dedicated cavo-aortic crossing techniques and closure devices.

Suprasternal Transcatheter Aortic Valve Replacement in Patients with Marginal Femoral Access

Objective

Recently, the PARTNER 2A trial reported results of transcatheter aortic valve replacement versus surgical aortic valve replacement in 2032 intermediate-risk patients at 2 years. Two hundred thirty-six patients (24%) required an access route other than transfemoral. Compared with transfemoral and surgical aortic valve replacement, nontransfemoral transcatheter aortic valve replacement was associated with a numerically higher rate of death and disabling stroke at 30 days. This underscores the need for a better alternative surgical approach for patients with marginal femoral access. We reviewed our multicenter experience with minimally invasive suprasternal transcatheter aortic valve replacement.

Methods

Consecutive patients with symptomatic severe aortic stenosis at high or intermediate risk for surgical aortic valve replacement underwent suprasternal transcatheter aortic valve replacement. A commercially available transcatheter heart valve was deployed under fluoroscopic guidance through the innominate artery or ascending aorta. Using a 3-cm skin incision just above the sternal notch, the Aegis Transit System (Aegis Surgical Ltd, Galway, Ireland) provided illuminated access to the mediastinum without bone disruption. Through a purse-string suture placed in the innominate artery or ascending aorta, transcatheter aortic valve replacement proceeded similarly to the direct aortic approach.

Results

Thirty patients at six medical centers successfully underwent suprasternal transcatheter aortic valve replacement. Implanted valves included 2 CoreValve and 12 Evolut-R (Medtronic, Inc, Minneapolis, MN USA), as well as 10 SAPIEN 3 and 6 SAPIEN XT (Edwards Lifesciences, Corp, Irvine, CA USA) with sizes ranging from 23 to 31 mm. Median procedure time was 90 minutes and median hospital stay was 4 days. Postoperatively, new permanent pacemaker (n = 3) was the most common Vascular Academic Research Consortium 2 complication.

Conclusions

These data demonstrate the early clinical feasibility of suprasternal transcatheter aortic valve replacement. Key advantages of this approach include direct access to the innominate artery and ascending aorta, precise sheath control, and confident arterial closure. Additional experience is warranted to confirm these favorable results.

The Impact of Transcatheter Aortic Valve Implantation and Surgical Aortic Valve Replacement on Left Ventricular Remodeling

Transcatheter aortic valve implantation (TAVI) appears to be equivalent to surgical aortic valve replacement (SAVR) with regard to clinical end points in high-risk and intermediate risk patients. Major landmark trials, such as Placement of Aortic Transcatheter Valves (PARTNER) trials 1 and 2 and US CoreValve show similar hemodynamic responses and left ventricular remodeling after both procedures. Real-life nonrandomized studies, however, suggest that TAVI may result in a somewhat better hemodynamic response and, therefore, a more favorable left ventricular remodeling than after SAVR for the first few years of follow-up. Further, there are fewer cases of prosthesis patient mismatch and more cases of paravalvular leak and conduction system abnormalities that affect the left ventricular remodeling process with TAVI than with SAVR. Overall, TAVI may be considered superior to SAVR in high-risk patients whose clinical outcome depends on a favorable remodeling process.

Cardiovascular magnetic resonance feature tracking in small animals - a preliminary study on reproducibility and sample size calculation

Background

Cardiovascular magnetic resonance feature tracking (CMR-FT) is a novel tissue tracking technique developed for noninvasive assessment of myocardial motion and deformation. This preliminary study aimed to evaluate the observer’s reproducibility of CMR-FT in a small animal (mouse) model and define sample size calculation for future trials.

Methods

Six C57BL/6 J mice were selected from the ongoing experimental mouse model onsite and underwent CMR with a 3 Tesla small animal MRI scanner. Myocardial deformation was analyzed using dedicated software (TomTec, Germany) by two observers. Left ventricular (LV) longitudinal, circumferential and radial strain (Ell_LAX, Ecc_SAX and Err_SAX) were calculated. To assess intra-observer agreement data analysis was repeated after 4 weeks. The sample size required to detect a relative change in strain was calculated.

Results

In general, Ecc_SAX and Ell_LAX demonstrated highest inter-observer reproducibility (ICC 0.79 (0.46–0.91) and 0.73 (0.56–0.83) Ecc_SAX and Ell_LAX respectively). In contrast, at the intra-observer level Ell_LAX was more reproducible than Ecc_SAX (ICC 0.83 (0.73–0.90) and 0.74 (0.49–0.87) Ell_LAX and Ecc_SAX respectively). The reproducibility of Err_SAX was weak at both observer levels. Preliminary sample size calculation showed that a small study sample (e.g. ten animals to detect a relative 10% change in Ecc_SAX) could be sufficient to detect changes if parameter variability is low.

Conclusions

This pilot study demonstrates good to excellent inter- and intra-observer reproducibility of CMR-FT technique in small animal model. The most reproducible measures are global circumferential and global longitudinal strain, whereas reproducibility of radial strain is weak. Furthermore, sample size calculation demonstrates that a small number of animals could be sufficient for future trials.

Cardiovascular magnetic resonance imaging to assess myocardial fibrosis in valvular heart disease

The left ventricular (LV) remodeling process associated with significant valvular heart disease (VHD) is characterized by an increase of myocardial interstitial space with deposition of collagen and loss of myofibers. These changes occur before LV systolic function deteriorates or the patient develops symptoms. Cardiovascular magnetic resonance (CMR) permits assessment of reactive fibrosis, with the use of T1 mapping techniques, and replacement fibrosis, with the use of late gadolinium contrast enhancement. In addition, functional consequences of these structural changes can be evaluated with myocardial tagging and feature tracking CMR, which assess the active deformation (strain) of the LV myocardium. Several studies have demonstrated that CMR techniques may be more sensitive than the conventional measures (LV ejection fraction or LV dimensions) to detect these structural and functional changes in patients with severe left-sided VHD and have shown that myocardial fibrosis may not be reversible after valve surgery. More important, the presence of myocardial fibrosis has been associated with lesser improvement in clinical symptoms and recovery of LV systolic function. Whether assessment of myocardial fibrosis may better select the patients with severe left-sided VHD who may benefit from surgery in terms of LV function and clinical symptoms improvement needs to be demonstrated in prospective studies. The present review article summarizes the current status of CMR techniques to assess myocardial fibrosis and appraises the current evidence on the use of these techniques for risk stratification of patients with severe aortic stenosis or regurgitation and mitral regurgitation.

The impact of trans-catheter aortic valve replacement induced left-bundle branch block on cardiac reverse remodeling

BACKGROUND

Left bundle branch block (LBBB) is common following trans-catheter aortic valve replacement (TAVR) and has been linked to increased mortality, although whether this is related to less favourable cardiac reverse remodeling is unclear. The aim of the study was to investigate the impact of TAVR induced LBBB on cardiac reverse remodeling.

METHODS

48 patients undergoing TAVR for severe aortic stenosis were evaluated. 24 patients with new LBBB (LBBB-T) following TAVR were matched with 24 patients with a narrow post-procedure QRS (nQRS). Patients underwent cardiovascular magnetic resonance (CMR) prior to and 6 m post-TAVR. Measured cardiac reverse remodeling parameters included left ventricular (LV) size, ejection fraction (LVEF) and global longitudinal strain (GLS). Inter- and intra-ventricular dyssynchrony were determined using time to peak radial strain derived from CMR Feature Tracking.

RESULTS

In the LBBB-T group there was an increase in QRS duration from 96 ± 14 to 151 ± 12 ms (P < 0.001) leading to inter- and intra-ventricular dyssynchrony (inter: LBBB-T 130 ± 73 vs nQRS 23 ± 86 ms, p < 0.001; intra: LBBB-T 118 ± 103 vs. nQRS 13 ± 106 ms, p = 0.001). Change in indexed LV end-systolic volume (LVESVi), LVEF and GLS was significantly different between the two groups (LVESVi: nQRS -7.9 ± 14.0 vs. LBBB-T -0.6 ± 10.2 ml/m2, p = 0.02, LVEF: nQRS +4.6 ± 7.8 vs LBBB-T -2.1 ± 6.9%, p = 0.002; GLS: nQRS -2.1 ± 3.6 vs. LBBB-T +0.2 ± 3.2%, p = 0.024). There was a significant correlation between change in QRS and change in LVEF (r = -0.434, p = 0.002) and between change in QRS and change in GLS (r = 0.462, p = 0.001). Post-procedure QRS duration was an independent predictor of change in LVEF and GLS at 6 months.

CONCLUSION

TAVR-induced LBBB is associated with less favourable cardiac reverse remodeling at medium term follow up. In view of this, every effort should be made to prevent TAVR-induced LBBB, especially as TAVR is now being extended to a younger, lower risk population.

Tissue Tracking Technology for Assessing Cardiac Mechanics: Principles, Normal Values, and Clinical Applications

Tissue tracking technologies such as speckle tracking echocardiography and feature tracking cardiac magnetic resonance have enhanced the noninvasive assessment of myocardial deformation in clinical research and clinical practice. The widespread enthusiasm for using tissue tracking techniques in research and clinical practice stems from the ready applicability of these technologies to routine echocardiographic or cardiac magnetic resonance images. The technology is common to both modalities, and derived parameters to describe myocardial mechanics are the similar, albeit with different accuracies. We provide an overview of the normal values and reproducibility of the clinically applicable parameters, together with their clinical validation. The use of these technologies in different clinical scenarios, and the additive value to current imaging diagnostics are discussed.

The role of cardiovascular magnetic resonance in the assessment of severe aortic stenosis and in post-procedural evaluation following transcatheter aortic valve implantation and surgical aortic valve replacement

Degenerative aortic stenosis (AS) is the most common valvular disease in the western world with a prevalence expected to double within the next 50 years. International guidelines advocate the use of cardiovascular magnetic resonance (CMR) as an investigative tool, both to guide diagnosis and to direct optimal treatment. CMR is the reference standard for quantifying both left and right ventricular volumes and mass, which is essential to assess the impact of AS upon global cardiac function. Given the ability to image any structure in any plane, CMR offers many other diagnostic strengths including full visualisation of valvular morphology, direct planimetry of orifice area, the quantification of stenotic jets and in particular, accurate quantification of valvular regurgitation. In addition, CMR permits reliable and accurate measurements of the aortic root and arch which can be fundamental to appropriate patient management. There is a growing evidence base to indicate tissue characterisation using CMR provides prognostic information, both in asymptomatic AS patients and those undergoing intervention. Furthermore, a number of current clinical trials will likely raise the importance of CMR in routine patient management. This article will focus on the incremental value of CMR in the assessment of severe AS and the insights it offers following valve replacement.

Transcatheter aortic valve implantation: current trends and future directions

Transcatheter aortic valve implantation (TAVI) has been increasingly utilized for the treatment of severe symptomatic aortic stenosis in inoperable and high surgical risk patients. Recent advances in valve technology include repositionable scaffolds and smaller delivery systems, as well as improvement in periprocedural imaging. These advances have resulted in reduction of vascular complications, rates of paravalvular aortic regurgitation and periprocedural stroke and improved overall outcomes. Increasingly, TAVI is the preferred treatment for high-risk surgical patients with severe aortic stenosis. Consequently, there is growing interest for the use of TAVI in lower surgical risk patients. Furthermore, the role of TAVI has expanded to include valve-in-valve procedures for the treatment of degenerative bioprosthetic valves and bicuspid aortic valves. Questions remain in regard to the optimal management of concurrent coronary artery disease, strategies to minimize valve leaflet restriction and treatment of conduction abnormalities as well as identifying newer indications for its use.

Myocardial injury associated with transcatheter aortic valve implantation (TAVI)

Transcatheter aortic valve implantation (TAVI) has emerged as an important treatment option for elderly patients with symptomatic aortic stenosis whose risk is too high or prohibitive for conventional surgery. Despite notable progress during the past decade, continuous efforts directed at further improvement of procedural safety and performance are required, especially considering expanding indications for interventional treatment options among lower-risk populations. One issue that needs to be addressed is myocardial damage, which can frequently be observed after TAVI and has been linked to worse prognosis. Yet, knowledge concerning the underlying mechanisms and clinical impact remains scarce, and further investigation in this field is warranted. In this review, we provide a contemporary summary of the types of myocardial injury associated with TAVI, including access-related injury, mechanical trauma and ischemia, the role of myocardial biomarkers, and the impact on left ventricular function, with emphasis on potential mechanisms and clinical implications.

Comparative survival after transapical, direct aortic, and subclavian transcatheter aortic valve implantation (data from the UK TAVI registry)

Many patients have iliofemoral vessel anatomy unsuitable for conventional transfemoral (TF) transcatheter aortic valve implantation (TAVI). Safe and practical alternatives to the TF approach are, therefore, needed. This study compared outcomes of alternative nonfemoral routes, transapical (TA), direct aortic (DA), and subclavian (SC), with standard femoral access. In this retrospective study, data from 3,962 patients in the UK TAVI registry were analyzed. All patients who received TAVI through a femoral, subclavian, TA, or DA approach were eligible for inclusion. The primary outcome measure was survival up to 2 years. Median Logistic EuroSCORE was similar for SC, DA, and TA but significantly lower in the TF cohort (22.1% vs 20.3% vs 21.2% vs 17.0%, respectively, p <0.0001). Estimated 1-year survival rate was similar for TF (84.6 ± 0.7%) and SC (80.5 ± 3%, p = 0.27) but significantly worse for TA (74.7 ± 1.6%, p <0.001) and DA (75.2 ± 3.3%, p <0.001). A Cox proportional hazard model was used to analyze survival up to 2 years. Survival in the SC group was not significantly different from the TF group (hazard ratio [HR] 1.22, 95% confidence interval [CI] 0.88 to 1.70, p = 0.24). In contrast, survival in the TA (HR 1.74, 95% CI 1.43 to 2.11; p <0.001) and DA (HR 1.55, 95% CI 1.13 to 2.14; p <0.01) cohorts was significantly reduced compared with TF. In conclusion, TA and DA TAVI were associated with similar survival, both significantly worse than with the TF route. In contrast, subclavian access was not significantly different from TF and may represent the safest nonfemoral access route for TAVI.

Temporal Trends in Quality of Life Outcomes After Transapical Transcatheter Aortic Valve Replacement: A Placement of AoRTic TraNscathetER Valve (PARTNER) Trial Substudy

BACKGROUND

In the Placement of AoRTic TraNscathetER Valve (PARTNER) randomized controlled trial (RCT), which represented the first exposure to transapical transcatheter aortic valve replacement (TA-TAVR) for many clinical sites, high-risk patients undergoing TA-TAVR derived similar health-related quality of life (HRQoL) outcomes when compared with surgical aortic valve replacement (SAVR). With increasing experience, it is possible that HRQoL outcomes of TA-TAVR may have improved.

METHODS AND RESULTS

We evaluated HRQoL outcomes at 1-, 6-, and 12-month follow-ups among 875 patients undergoing TA-TAVR in the PARTNER nonrandomized continued access (NRCA) registry and compared these outcomes with those of the TA-TAVR and SAVR patients in the PARTNER RCT. HRQoL was assessed with the Kansas City Cardiomyopathy Questionnaire (KCCQ), the Medical Outcomes Study Short-Form 12, and the EuroQoL-5D, with the KCCQ overall summary score serving as the primary end point. The NRCA TA-TAVR and RCT TA-TAVR and SAVR groups were generally similar. The primary outcome, the KCCQ summary score, did not differ between the NRCA TA-TAVR and the RCT TA-TAVR group at any follow-up timepoints, although there were small differences in favor of the NRCA cohort on several KCCQ subscales at 1 month. There were no significant differences in follow-up HRQOL between the NRCA-TAVR and the RCT SAVR cohorts on the KCCQ overall summary scale or any of the disease-specific or generic subscales.

CONCLUSIONS

Despite greater experience with TA-TAVR in the NRCA registry, HRQoL outcomes remained similar to those of TA-TAVR in the original RCT cohort and no better than those with SAVR. These findings have important implications for patient selection for TAVR when transfemoral access is not an option.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00530894.

Fully percutaneous transthoracic left atrial entry and closure as a potential access route for transcatheter mitral valve interventions

BACKGROUND

Percutaneous access for mitral interventions is currently limited to transapical and transseptal routes, both of which have shortcomings. We hypothesized that the left atrium could be accessed directly through the posterior chest wall under imaging guidance.

METHODS AND RESULTS

We tested percutaneous transthoracic left atrial access in 12 animals (10 pigs and 2 sheep) under real-time magnetic resonance imaging or x-ray fluoroscopy plus C-arm computed tomographic guidance. The pleural space was insufflated with CO2 to displace the lung, an 18F sheath was delivered to the left atrium, and the left atrial port was closed using an off-the-shelf nitinol cardiac occluder. Animals were survived for a minimum of 7 days. The left atrial was accessed, and the port was closed successfully in 12/12 animals. There was no procedural mortality and only 1 hemodynamically insignificant pericardial effusion was observed at follow-up. We also successfully performed the procedure on 3 human cadavers. A simulated trajectory to the left atrium was present in all of 10 human cardiac computed tomographic angiograms analyzed.

CONCLUSIONS

Percutaneous transthoracic left atrial access is feasible without instrumenting the left ventricular myocardium. In our experience, magnetic resonance imaging offers superb visualization of anatomic structures with the ability to monitor and address complications in real-time, although x-ray guidance seems feasible. Clinical translation seems realistic based on human cardiac computed tomographic analysis and cadaver testing. This technique could provide a direct nonsurgical access route for future transcatheter mitral implantation.

Transaortic Transcatheter Aortic Valve Implantation as a Second Choice over the Transapical Access

BACKGROUND AND AIMS

In this report, we present our experience with the transaortic transcatheter aortic valve implantation using the SAPIEN valve. The procedural success, 30-day outcome, and survival up to 2 years are compared with the transapical access performed in patients in our institution.

MATERIAL AND METHODS

Of a total of 282 transcatheter aortic valve implantation patients, 100 consecutive patients had a non-transfemoral approach. The transaortic and transapical access routes were used in 36 and 64 patients, respectively. The transaortic group had a higher mean logistic EuroSCORE (32.6 vs 25.2, p = 0.021) and more patients with left ventricular ejection fraction less than 40% (33.3% vs 14.1%, p = 0.023).

RESULTS

The respective technical success rates for the transaortic and transapical groups were 100% and 95.2% (p = NS). There were significantly more perioperative hemodynamic problems necessitating cardiopulmonary resuscitation or mechanical circulatory support in the transapical group (18.8% vs 2.8%, p = 0.023). The transaortic group had a slightly shorter hospital stay (7 vs 8 days, p = 0.018). The 30-day mortality was 8.6% and 10.9% in the transaortic and transapical group, respectively (p = NS). Combined safety outcome was similar in both groups at 30 days. The respective 1-year survival rates for the transaortic and transapical groups were 71.5% and 68.3%, respectively (p = NS).

CONCLUSION

The trans transcatheter aortic valve implantation is a considerable choice to transapical approach. Despite a higher risk patient cohort, the clinical outcome is at least comparable to the transapical transcatheter aortic valve implantation, and it can be utilized as a second choice for patients with prohibitive iliac-femoral anatomy for transfemoral access.

Nontransfemoral Approaches to Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) is noninferior to surgical aortic valve replacement in patients with high operative risk and superior to medical treatment in patients deemed unsuitable for surgical intervention. However, up to 30% to 50% of patients screened for this intervention are not candidates for TAVR via the preferred transfemoral route because of severe peripheral arterial disease. Alternative access routes must be considered and include the transapical, transaortic, transsubclavian, and transcarotid approaches. The use of alternative access is predicated on appropriate patient selection as determined by a dedicated multispecialty heart valve team and can lead to excellent outcomes.