Quantitative multi-slice computed tomography assessment of the mitral valvular complex for transcatheter mitral valve interventions part 1: systematic measurement methodology and inter-observer variability.

AIMS: Transcatheter mitral valve replacement (TMVR) is an emerging technology with the potential to treat patients with severe mitral regurgitation at excessive risk for surgical mitral valve surgery. Multimodality imaging of the mitral valvular complex and surrounding structures will be an important component for patient selection for TMVR. Our aim was to describe and evaluate a systematic multi-slice computed tomography (MSCT) image analysis methodology that provides measurements relevant for transcatheter mitral valve replacement. METHODS AND RESULTS: A systematic step-by-step measurement methodology is described for structures of the mitral valvular complex including: the mitral valve annulus, left ventricle, left atrium, papillary muscles and left ventricular outflow tract. To evaluate reproducibility, two observers applied this methodology to a retrospective series of 49 cardiac MSCT scans in patients with heart failure and significant mitral regurgitation. For each of 25 geometrical metrics, we evaluated inter-observer difference and intra-class correlation. The inter-observer difference was below 10% and the intra-class correlation was above 0.81 for measurements of critical importance in the sizing of TMVR devices: the mitral valve annulus diameters, area, perimeter, the inter-trigone distance, and the aorto-mitral angle. CONCLUSIONS: MSCT can provide measurements that are important for patient selection and sizing of TMVR devices. These measurements have excellent inter-observer reproducibility in patients with functional mitral regurgitation.

Quantitative multi-slice computed tomography assessment of the mitral valvular complex for transcatheter mitral valve interventions part 2: geometrical measurements in patients with functional mitral regurgitation.

AIMS: Transcatheter mitral valve replacement (TMVR) is an emerging technology with the potential to treat patients with mitral regurgitation at excessive risk for mitral valve surgery. Geometrical measurements of the mitral valvular complex may have implications for the design of TMVR devices and for patient selection. This study sought to quantify the dynamic geometry of the mitral valvular complex in patients with significant functional mitral regurgitation (FMR) using multi-slice computed tomography (MSCT). METHODS AND RESULTS: MSCT images were acquired in 32 patients with symptomatic, significant FMR. Two independent observers analysed image sets using a dedicated software package and a standard measurement methodology. In patients with FMR, the mean mitral annulus intercommissural and aorto-mural diameters were, respectively, 41.5±5.2 mm and 38.7±5.9 mm in systole, and were 41.5±4.4 mm and 40.0±4.7 mm in diastole. In patients without MR, the diameters were, respectively, 33.6±5.1 mm and 28.8±8.0 mm in systole, and 36.2±4.5 mm and 31.6±7.9 mm in diastole. The obstacle-free zone below the mitral annulus averaged more than 20.0 mm and varied by less than 1 mm between systole and diastole, which is not statistically significant. The aorto-mitral angle was 129.7±10.5° in systole and 131.0±9.4° in diastole. CONCLUSIONS: The mitral annulus is larger in dimension, more circular, and less dynamic in patients with FMR. The obstacle-free zone below the mitral annulus is relatively constant during the cardiac cycle. Measurements of the mitral valvular apparatus vary considerably between patients, which suggests that tridimensional imaging will play an important role in the sizing of TMVR devices.

Transcatheter heart valve failure: a systematic review.

AIMS: A comprehensive description of transcatheter heart valve (THV) failure has not been performed. We undertook a systematic review to investigate the aetiology, diagnosis, management, and outcomes of THV failure. METHODS AND RESULTS: The systematic review was performed in accordance with the PRISMA guidelines using EMBASE, MEDLINE, and Scopus. Between December 2002 and March 2014, 70 publications reported 87 individual cases of transcatheter aortic valve implantation (TAVI) failure. Similar to surgical bioprosthetic heart valve failure, we observed cases of prosthetic valve endocarditis (PVE) (n = 34), structural valve failure (n = 13), and THV thrombosis (n = 15). The microbiological profile of THV PVE was similar to surgical PVE, though one-quarter had satellite mitral valve endocarditis, and surgical intervention was required in 40% (75% survival). Structural valve failure occurred most frequently due to leaflet calcification and was predominantly treated by redo-THV (60%). Transcatheter heart valve thrombosis occurred at a mean 9 ± 7 months post-implantation and was successfully treated by prolonged anticoagulation in three-quarters of cases. Two novel causes of THV failure were identified: late THV embolization (n = 18); and THV compression (n = 7) following cardiopulmonary resuscitation (CPR). These failure modes have not been reported in the surgical literature. Potential risk factors for late THV embolization include low prosthesis implantation, THV undersizing/underexpansion, bicuspid, and non-calcified anatomy. Transcatheter heart valve embolization mandated surgery in 80% of patients. Transcatheter heart valve compression was noted at post-mortem in most cases. CONCLUSION: Transcatheter heart valves are susceptible to failure modes typical to those of surgical bioprostheses and unique to their specific design. Transcatheter heart valve compression and late embolization represent complications previously unreported in the surgical literature.

Transcatheter aortic valve replacement in bicuspid aortic valve disease.

BACKGROUND: Limited information exists describing the results of transcatheter aortic valve (TAV) replacement in patients with bicuspid aortic valve (BAV) disease (TAV-in-BAV). OBJECTIVES: This study sought to evaluate clinical outcomes of a large cohort of patients undergoing TAV-in-BAV. METHODS: We retrospectively collected baseline characteristics, procedural data, and clinical follow-up findings from 12 centers in Europe and Canada that had performed TAV-in-BAV. RESULTS: A total of 139 patients underwent TAV-in-BAV with the balloon-expandable transcatheter heart valve (THV) (n = 48) or self-expandable THV (n = 91) systems. Patient mean age and Society of Thoracic Surgeons predicted risk of mortality scores were 78.0 ± 8.9 years and 4.9 ± 3.4%, respectively. BAV stenosis occurred in 65.5%, regurgitation in 0.7%, and mixed disease in 33.8% of patients. Incidence of type 0 BAV was 26.7%; type 1 BAV was 68.3%; and type 2 BAV was 5.0%. Multislice computed tomography (MSCT)-based TAV sizing was used in 63.5% of patients (77.1% balloon-expandable THV vs. 56.0% self-expandable THV, p = 0.02). Procedural mortality was 3.6%, with TAV embolization in 2.2% and conversion to surgery in 2.2%. The mean aortic gradient decreased from 48.7 ± 16.5 mm Hg to 11.4 ± 9.9 mm Hg (p < 0.0001). Post-implantation aortic regurgitation (AR) grade ≥ 2 occurred in 28.4% (19.6% balloon-expandable THV vs. 32.2% self-expandable THV, p = 0.11) but was prevalent in only 17.4% when MSCT-based TAV sizing was performed (16.7% balloon-expandable THV vs. 17.6% self-expandable THV, p = 0.99). MSCT sizing was associated with reduced AR on multivariate analysis (odds ratio [OR]: 0.19, 95% confidence intervals [CI]: 0.08 to 0.45; p < 0.0001). Thirty-day device safety, success, and efficacy were noted in 79.1%, 89.9%, and 84.9% of patients, respectively. One-year mortality was 17.5%. Major vascular complications were associated with increased 1-year mortality (OR: 5.66, 95% CI: 1.21 to 26.43; p = 0.03). CONCLUSIONS: TAV-in-BAV is feasible with encouraging short- and intermediate-term clinical outcomes. Importantly, a high incidence of post-implantation AR is observed, which appears to be mitigated by MSCT-based TAV sizing. Given the suboptimal echocardiographic results, further study is required to evaluate long-term efficacy.

Erroneous measurement of the aortic annular diameter using 2-dimensional echocardiography resulting in inappropriate CoreValve size selection: a retrospective comparison with multislice computed tomography.

OBJECTIVES: This study sought to assess the differential adherence to transcatheter heart valve (THV)-oversizing principles between transesophageal echocardiography (TEE) and multislice computed tomography (CT) and its impact on the incidence of paravalvular leak (PVL). BACKGROUND: CT has emerged as an alternative to 2-dimensional TEE for THV sizing. METHODS: In our early experience, TEE-derived aortic annular diameters determined THV size selection. CT datasets originally obtained for vascular screening were retrospectively interrogated to determine CT-derived annular diameters. Annular dimensions and expected THV oversizing were compared between TEE and CT. The incidence of PVL was correlated to TEE- and CT-based oversizing calculations. RESULTS: Using TEE-derived annulus measurements, 157 patients underwent CoreValve implantation (23 mm: n = 66; 29 mm: n = 91). The estimated THV oversizing on the basis of TEE was 20.1 ± 8.2%. Retrospective CT analysis yielded larger annular diameters than TEE (p < 0.0001). When these CT diameters were used to recalculate the percentage of oversizing achieved with the TEE-selected CoreValve, the actual THV oversizing was only 10.4 ± 7.8%. Consequently, CT analysis suggested that up to 50% of patients received an inappropriate CoreValve size. When CT-based sizing criteria were satisfied, the incidence of PVL was 21% lower than that with echocardiography (14% vs. 35%; p = 0.003). Adherence to CT-based oversizing was independently associated with a reduced incidence of PVL (odds ratio 0.36; 95% confidence interval: 0.14 to 0.90; p = 0.029); adherence to TEE-based sizing was not. CONCLUSIONS: Retrospective CT-based annular analysis revealed that CoreValve size selection by TEE was incorrect in 50% of patients. The percentage of oversizing with CT was one-half of that calculated with TEE resulting in the majority of patients receiving a THV that was too small.

Early results of a novel technique for ring-reinforced aortic valve and root restoration.

OBJECTIVES: Surgery for aortic root aneurysm without valve stenosis is increasingly being transformed from the Bentall procedure to valve-sparing aortic root remodelling or reimplantation. In this report, a new repair option is explored, with full functional 'restoration' of the aortic root complex using a geometric annuloplasty ring, leaflet repair, and sinus/ascending aortic replacement with a Valsalva graft. METHODS: The geometric annuloplasty ring restores elliptical annular shape and size in patients with tri-leaflet aortic insufficiency (AI). The ring mounts the three valve commissures on 10° outwardly flaring posts, and facilitates required leaflet procedures. In clinical application, the device has been effective in achieving stable AI reduction with low valve gradients. In this report, 6 patients with aortic root aneurysms and moderate/severe AI were managed with valve repair using the annuloplasty device and leaflet reconstruction, and then concomitant sinus and ascending aortic graft replacement with coronary implantation. RESULTS: In the 6 initial root aneurysm patients, there were no in-hospital mortalities, procedural conversions, or valve-related complications. Preoperative AI grade was 2-4 and fell to 0-1 postoperatively. Post-repair mean systolic gradients ranged from 7 to 12 mmHg, and all patients had stable intermediate-term valve function. CONCLUSIONS: Aortic root restoration using a geometric annuloplasty ring and Valsalva graft may be the most physiological method of aortic valve repair and root replacement. Even with severe leaflet derangements, valve sparing can be achieved with good competence and potentially stable long-term results. This technique could assist in extending valve sparing into most categories of aortic root disease. CLINICAL TRIALS: Patients were managed as part of a Phase I (ClinicalTrials.gov Identifier: NCT01400841), supported by BioStable Science and Engineering (BSE), Austin, TX, USA; www.biostable-s-e.com.

A systematic review and meta-analysis of surgical outcomes following mitral valve surgery in octogenarians: implications for transcatheter mitral valve interventions.

AIMS: To evaluate the outcomes of mitral valve surgery in octogenarians with severe symptomatic mitral regurgitation (MR). METHODS AND RESULTS: We performed a systematic review and meta-analysis of data on octogenarians who underwent mitral valve replacement (MVR) or mitral valve repair (MVRpr). Our search yielded 16 retrospective studies. Using Bayesian hierarchical models, we estimated the pooled proportion of 30-day mortality, postoperative stroke, and long-term survival. The pooled proportion of 30-day postoperative mortality was 13% following MVR (10 studies, 3,105 patients, 95% credible interval [CI] 9-18%), and 7% following MVRpr (six studies, 2,642 patients, 95% CI: 3-12%). Furthermore, pooled proportions of postoperative stroke were 4% (six studies, 2,945 patients, 95% CI: 3-7%) and 3% (three studies, 348 patients, 95% CI: 1-8%) for patients undergoing MVR and MVRpr, respectively. Pooled survival rates at one and five years following MVR (four studies, 250 patients) were 67% (95% CI: 50-80%) and 29% (95% CI: 16-47%), and following MVRpr (three studies, 333 patients) were 69% (95% CI: 50-83%) and 23% (95% CI: 12-39%), respectively. CONCLUSIONS: Surgical treatment of MR in octogenarians is associated with high perioperative mortality and poor long-term survival with an uncertain benefit on quality of life. These data highlight the importance of patient selection for operative intervention and suggest that future transcatheter mitral valve therapies such as transcatheter mitral valve repair (TMVr) and/or transcatheter mitral valve implantation (TMVI), may provide an alternative therapeutic approach in selected high-risk elderly patients.