Anita W. Asgar

Multimodality Imaging in Transcatheter Aortic Valve Implantation and Post-Procedural Aortic Regurgitation : Comparison Among Cardiovascular Magnetic Resonance, Cardiac Computed Tomography, and Echocardiography

OBJECTIVES The purpose of this study was to determine imaging predictors of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) and the agreement and reproducibility of cardiovascular magnetic resonance (CMR), cardiac computed tomography (CCT), and transthoracic echocardiography (TTE) in aortic root assessment. BACKGROUND The optimal imaging strategy for planning TAVI is unclear with a paucity of comparative multimodality imaging data. The association between aortic root morphology and outcomes after TAVI also remains incompletely understood. METHODS A total of 202 consecutive patients assessed by CMR, CCT, and TTE for TAVI were studied. Agreement and variability among and within imaging modalities was assessed by Bland-Altman analysis. Postoperative AR was assessed by TTE. RESULTS Of the 202 patients undergoing TAVI assessment with both CMR and TTE, 133 also underwent CCT. Close agreement was observed between CMR and CCT in dimensions of the aortic annulus (bias, -0.4 mm; 95% limits of agreement: -5.7 to 5.0 mm), and similarly for sinus of Valsalva, sinotubular junction, and ascending aortic measures. Agreement between TTE-derived measures and either CMR or CCT was less precise. Intraobserver and interobserver variability were lowest with CMR. The presence and severity of AR after TAVI were associated with larger aortic valve annulus measurements by both CMR (p = 0.03) and CCT (p = 0.04) but not TTE-derived measures (p = 0.10). Neither CCT nor CMR measures of annulus eccentricity, however, predicted AR after TAVI (p = 0.33 and p = 0.78, respectively). CONCLUSIONS In patients undergoing imaging assessment for TAVI, the presence and severity of AR after TAVI were associated with larger aortic annulus measurements by both CMR and CCT, but not TTE. Both CMR and CCT provide highly reproducible information in the assessment of patients undergoing TAVI.

Secondary Mitral Regurgitation in Heart Failure : Pathophysiology, Prognosis, and Therapeutic Considerations

The development of secondary mitral regurgitation (MR) due to left ventricular dysfunction, also known as functional MR, is strongly associated with a poor prognosis in patients with heart failure. The mechanisms underlying secondary MR are multifactorial; accurate imaging assessment of secondary MR may be challenging and nuanced; and the appropriate roles of medical, surgical, and interventional therapies for management of secondary MR are controversial and evolving. In this review, the pathophysiology, evaluation, and prognosis of secondary MR in patients with heart failure are discussed, and we evaluate in detail the evidence for the various therapeutic approaches for secondary MR, including guideline-directed medication for left ventricular dysfunction, cardiac resynchronization therapy and revascularization when appropriate, and mitral valve surgery and transcatheter interventions. The role of a multidisciplinary heart team in determining the optimal management strategy for secondary MR is also discussed.

Novel therapeutic aspects of percutaneous aortic valve replacement with the 21F CoreValve Revalving™ System

Aims: Percutaneous aortic valve replacement (PAVR) is an emerging therapy for nonsurgical patients with severe aortic stenosis (AS). We investigated whether novel therapeutic approaches may facilitate AVR outcomes for high‐risk patients. Methods and Results: Eleven patients [n = 6 (54%) men] aged 82 ± 10 years underwent PAVR after being refused for open surgery. The mean±SD AV area and left ventricular ejection fraction (LVEF) of these patients was 0.56 ± 0.19 cm2 and 49 ± 17%, respectively, with severe functional limitation (NYHA class III (n = 8) and IV (n = 3)). One patient underwent PAVR combined with simultaneous percutaneous coronary intervention (PCI). Two male patients needed left iliac artery angioplasty. A percutaneous ventricular assist device (PVAD) was used in the most recent case. Compared with pre‐PAVR, mean AV area (1.3 ± 0.4 cm2; P < 0.001) and LVEF (56 ± 11%; P < 0.001) increased. One man had a peri‐procedural stroke and died 5 days post‐PAVR. Four other patients died within 4 months of hospital discharge. The median duration of survival of the survivors was 305 (range 249–431) days. Conclusions: Novel percutaneous techniques facilitate CoreValve PAVR (21 Fr.). Future lower profile devices (e.g. 18 Fr. Generation III CoreValve) should permit inclusion of a broader spectrum of high‐risk patients. PAVR may evolve toward a full percutaneous approach.

Fontan Circulation: Success or Failure?

Fontan surgery represents a milestone in the evolution of congenital heart disease management. It achieved the seemingly improbable (ie, restoration of a noncyanotic state by entirely bypassing the subpulmonary ventricle). In so doing, it has allowed a generation of children who may have otherwise succumbed to their severe congenital heart defect to survive to adulthood. Perfect univentricular physiology is, however, an elusive goal. The Fontan circulation inherently represents a hemodynamic compromise that results in a catalog of potential multiorgan complications. In this review, we explore current knowledge regarding pathophysiology of the failing Fontan, its varied clinical manifestations, and potential therapeutic options. Failure of the Fontan circulation is broadly divided into 3 overlapping categories: ventricular dysfunction, systemic complications of Fontan physiology, and chronic Fontan failure. As long as the Fontan operation continues to serve as the paradigm of care for patients with univentricular hearts, efforts must be directed toward supporting this dynamic circulation that progressively declines in efficiency with age. Continued research in therapies is needed for univentricular dysfunction and systemic complications of Fontan palliation, including potential uses of mechanical support as a bridge to transplantation or as a neosubpulmonary ventricle. Fontan patients remain a major challenge to the medical and surgical community as a whole. Multicentre and multidisciplinary efforts to improve the density and depth of experiences might lead to a better appreciation for, and management of, Fontan failure and its ramifications.

Transcatheter Reduction of Paravalvular Leaks: A Systematic Review and Meta-analysis

BACKGROUND Significant paravalvular leak (PVL) after surgical valve replacement can result in intractable congestive heart failure and hemolytic anemia. Because repeat surgery is performed in only few patients, transcatheter reduction of PVL is emerging as an alternative option, but its safety and efficacy remain uncertain. In this study we sought to assess whether a successful transcatheter PVL reduction is associated with an improvement in clinical outcomes. METHODS We identified 12 clinical studies that compared successful and failed transcatheter PVL reductions in a total of 362 patients. A Bayesian hierarchical meta-analysis was performed using cardiac mortality as a primary end point. The combined occurrence of improvement in New York Heart Association functional class or hemolytic anemia and the need for repeat surgery, were used as secondary end points. RESULTS A successful transcatheter PVL reduction was associated with a lower cardiac mortality rate (odds ratio [OR], 0.08; 95% credible interval [CrI], 0.01-0.90) and with a superior improvement in functional class or hemolytic anemia, compared with a failed intervention (OR, 9.95; 95% CrI, 2.10-66.73). Fewer repeat surgeries were also observed after successful procedures (OR, 0.08; 95% CrI, 0.01-0.40). CONCLUSIONS A successful transcatheter PVL reduction is associated with reduced all-cause mortality and improved functional class in patients deemed unsuitable for surgical correction.

Bivalirudin Versus Heparin Anticoagulation in Transcatheter Aortic Valve Replacement: The Randomized BRAVO-3 Trial.

BACKGROUND Anticoagulation is required during transcatheter aortic valve replacement (TAVR) procedures. Although an optimal regimen has not been determined, heparin is mainly used. Direct thrombin inhibition with bivalirudin may be an effective alternative to heparin as the procedural anticoagulant agent in this setting. OBJECTIVES The goal of this study was to determine whether bivalirudin offers an alternative to heparin as the procedural anticoagulant agent in patients undergoing TAVR. METHODS A total of 802 patients with aortic stenosis were randomized to undergo transfemoral TAVR with bivalirudin versus unfractionated heparin during the procedure. The 2 primary endpoints were major bleeding within 48 h or before hospital discharge (whichever occurred first) and 30-day net adverse clinical events, defined as the combination of major adverse cardiovascular events (all-cause mortality, myocardial infarction, or stroke) and major bleeding. RESULTS Anticoagulation with bivalirudin versus heparin did not meet superiority because it did not result in significantly lower rates of major bleeding at 48 h (6.9% vs. 9.0%; relative risk: 0.77; 95% confidence interval [CI]: 0.48 to 1.23; p = 0.27) or net adverse cardiovascular events at 30 days (14.4% vs. 16.1%; relative risk: 0.89; 95% CI: 0.64 to 1.24; risk difference: -1.72; 95% CI: -6.70 to 3.25; p = 0.50); regarding the latter, the prespecified noninferiority hypothesis was met (pnoninferiority < 0.01). Rates of major adverse cardiovascular events at 48 h were not significantly different (3.5% vs. 4.8%; relative risk: 0.73; 95% CI: 0.37 to 1.43; p = 0.35). At 48 h, the bivalirudin group had significantly fewer myocardial infarctions but more acute kidney injury events than the heparin group; at 30 days, these differences were no longer significant. CONCLUSIONS In this randomized trial of TAVR procedural pharmacotherapy, bivalirudin did not reduce rates of major bleeding at 48 h or net adverse cardiovascular events within 30 days compared with heparin. Although superiority was not shown, the noninferiority hypothesis was met with respect to the latter factor. Given the lower cost, heparin should remain the standard of care, and bivalirudin can be an alternative anticoagulant option in patients unable to receive heparin in TAVR. (International, Multi-center, Open-label, Randomized Controlled Trial in Patients Undergoing TAVR to Determine the Treatment Effect [Both Safety and Efficacy] of Using Bivalirudin Instead of UFH [BRAVO-2/3]; NCT01651780).

Anatomo-pathological analysis after CoreValve Revalving system implantation.

AIMS Significant technological improvements have made percutaneous aortic valve replacement (PAVR) simpler and safer, but the behaviour of the implanted valve over time remains unknown. We report the anatomo-pathological analysis of patients who died at different time intervals post PAVR with the CoreValve Revalving System. METHODS AND RESULTS In our early experience, 21 patients underwent CoreValve implantation between 12/2005 and 02/2007. Among the 11 deaths at one year follow-up, four patients had an autopsy with macro and microscopic analysis. The device was divided in three parts during pathological assessment: the lower portion (area 1), the leaflets (area 2) and the upper part (area 3). The CoreValves were implanted for 3, 13, 104 and 350 days. Gross examination showed neointimal tissue covering most of the frame struts in contact with the aortic wall, but areas of high velocity blood flow were bare. Histopathology examination demonstrated fibrin deposition and inflammatory response early after valve implantation, followed by neointimal coverage with progressive regression of the inflammatory response over time. CONCLUSIONS While waiting for results of longer term PAVR echocardiographic follow-up, the anatomic assessment is encouraging with neointimal coverage of the native valve site and no excessive pannus formation occurring over the valve leaflets.

Transcatheter Mitral and Pulmonary Valve Therapy

As the percentage of seniors continues to rise in many populations around the world, the already challenging burden of valvular heart disease will become even greater. Unfortunately, a significant proportion of patients with moderate-to-severe valve disease are refused or denied valve surgery based on age and/or accompanying comorbidities. Furthermore, because of advances in pediatric cardiology, the number of adult patients with congenital heart disease is on the rise and over time, these patients will likely require repeat high-risk surgical procedures. The aim of transcatheter valve therapies is to provide a minimally invasive treatment that is at least as effective as conventional valve surgery and is associated with less morbidity and mortality. The objective of this review was to provide an update on the clinical status, applicability, and limitations of transcatheter mitral and pulmonary valve therapies.

Adult congenital heart disease: a growing epidemic.

Medical and surgical breakthroughs in the care of children born with heart defects have generated a growing population of adult survivors and spawned a new subspecialty of cardiology: adult congenital heart disease. The prevalence of adult congenital heart disease is escalating at a rampant rate, outpacing the relatively static prevalence of pediatric congenital heart disease, because adults now surpass children in numbers by a ratio of 2:1. As such, congenital heart disease can no longer be considered primarily a pediatric specialty. Most congenital heart defects are not curable and require lifelong specialized care. Health care systems worldwide are challenged to meet the unique needs of this increasingly complex patient population, including the development of supraregional centres of excellence to provide comprehensive and multidisciplinary specialized care. In this review, we explore the incidence and prevalence of congenital heart disease and their changing patterns, address organization and delivery of care, highlight the importance of appropriate training and dedicated research, summarize the high burden of health care resource utilization, and provide an overview of common issues encountered in adults with congenital heart disease.

The Benefits Conferred by Radial Access for Cardiac Catheterization Are Offset by a Paradoxical Increase in the Rate of Vascular Access Site Complications With Femoral Access : The Campeau Radial Paradox

OBJECTIVES The purpose of this study was to assess whether the benefits conferred by radial access (RA) at an individual level are offset by a proportionally greater incidence of vascular access site complications (VASC) at a population level when femoral access (FA) is performed. BACKGROUND The recent widespread adoption of RA for cardiac catheterization has been associated with increased rates of VASCs when FA is attempted. METHODS Logistic regression was used to calculate the adjusted VASC rate in a contemporary cohort of consecutive patients (2006 to 2008) where both RA and FA were used, and compared it with the adjusted VASC rate observed in a historical control cohort (1996 to 1998) where only FA was used. We calculated the adjusted attributable risk to estimate the proportion of VASC attributable to the introduction of RA in FA patients of the contemporary cohort. RESULTS A total of 17,059 patients were included. At a population level, the VASC rate was higher in the overall contemporary cohort compared with the historical cohort (adjusted rates: 2.91% vs. 1.98%; odds ratio [OR]: 1.48, 95% confidence interval [CI]: 1.17 to 1.89; p = 0.001). In the contemporary cohort, RA patients experienced fewer VASC than FA patients (adjusted rates: 1.44% vs. 4.19%; OR: 0.33, 95% CI: 0.23 to 0.48; p < 0.001). We observed a higher VASC rate in FA patients in the contemporary cohort compared with the historical cohort (adjusted rates: 4.19% vs. 1.98%; OR: 2.16, 95% CI: 1.67 to 2.81; p < 0.001). This finding was consistent for both diagnostic and therapeutic catheterizations separately. The proportion of VASCs attributable to RA in the contemporary FA patients was estimated at 52.7%. CONCLUSIONS In a contemporary population where both RA and FA were used, the safety benefit associated with RA is offset by a paradoxical increase in VASCs among FA patients. The existence of this radial paradox should be taken into consideration, especially among trainees and default radial operators.