Acute Left Atrial Appendage Thrombus Formation During Transcatheter Mitral Valve Edge-to-Edge Repair.

We present a case of a 75-year-old man who developed an acute left atrial appendage thrombus immediately following mitral valve transcatheter edge to edge repair despite adequate intraprocedural anticoagulation. The patient was managed with enoxaparin to warfarin bridging with no obvious thromboembolic events on follow-up. Attention to anticoagulation is important to reduce thromboembolic risk during mitral valve transcatheter edge to edge repair. (Level of Difficulty: Intermediate.).

Home-Based Cardiac Rehabilitation: EXPERIENCE FROM THE VETERANS AFFAIRS.

PURPOSE: The conceptual utility of home-based cardiac rehabilitation (HBCR) is widely acknowledged. However, data substantiating its effectiveness and safety are limited. This study evaluated effectiveness and safety of the Veterans Affairs (VA) national HBCR program. METHODS: Veterans completed a 12-wk HBCR program over 18 mo at 25 geographically dispersed VA hospitals. Pre- to post-changes were compared using paired t tests. Patient satisfaction and adverse events were also summarized descriptively. RESULTS: Of the 923 Veterans with a mean age of 67.3 ± 10.6 yr enrolled in the HBCR program, 572 (62%) completed it. Findings included significant improvements in exercise capacity (6-min walk test distance: 355 vs 398 m; P < .05; Duke Activity Status Index: 27.1 vs 33.5; P < .05; self-reported steps/d: 3150 vs 4166; P < .05); depression measured by Patient Health Questionnaire (6.4 vs 4.9; P < .0001); cardiac self-efficacy (33.1 vs 39.2; P < .0001); body mass index (31.5 vs 31.1 kg/m2; P = .0001); and eating habits measured by Rate Your Plate, Heart (47.2 vs 51.1; P < .05). No safety issues were related to HBCR participation. Participants were highly satisfied. CONCLUSIONS: The VA HBCR program demonstrates strong evidence of effectiveness and safety to a wide range of patients, including those with high clinical complexity and risk. HBCR provides an adjunct to site-based programs and access to cardiac rehabilitation. Additional research is needed to assess long-term effects, cost-effectiveness, and sustainability of the model.

Cardiac Rehabilitation During COVID-19 Pandemic: Highlighting the Value of Home-Based Programs.

Cardiac rehabilitation (CR) is a class I treatment for cardiovascular disease, however, underutilization of these services remains. Home-based CR (HBCR) models have been implemented as a potential solution to addressing access barriers to CR services. Home-based models have been shown to be effective, however, there continues to be large variation of protocols and minimal evidence of effectiveness in higher risk populations. In addition, lack of reimbursement models has discouraged the widespread adoption of HBCR. During the coronavirus 2019 (COVID-19) pandemic, an even greater gap in CR care has been present due to decreased availability of on-site services. The COVID-19 pandemic presents a time to highlight the value and experiences of home-based models as clinicians search for ways to continue to provide care. Continued review and standardization of HBCR models are essential to provide care for a wider range of patients and circumstances.

Discovery of an Experimental Model of Unicuspid Aortic Valve.

BACKGROUND: The epithelial growth factor receptor family of tyrosine kinases modulates embryonic formation of semilunar valves. We hypothesized that mice heterozygous for a dominant loss-of-function mutation in epithelial growth factor receptor, which are EgfrVel/+ mice, would develop anomalous aortic valves, valve dysfunction, and valvular cardiomyopathy. METHODS AND RESULTS: Aortic valves from EgfrVel/+ mice and control mice were examined by light microscopy at 2.5 to 4 months of age. Additional EgfrVel/+ and control mice underwent echocardiography at 2.5, 4.5, 8, and 12 months of age, followed by histologic examination. In young mice, microscopy revealed anatomic anomalies in 79% of EgfrVel/+ aortic valves, which resembled human unicuspid aortic valves. Anomalies were not observed in control mice. At 12 months of age, histologic architecture was grossly distorted in EgfrVel/+ aortic valves. Echocardiography detected moderate or severe aortic regurgitation, or aortic stenosis was present in 38% of EgfrVel/+ mice at 2.5 months of age (N=24) and in 74% by 8 months of age. Left ventricular enlargement, hypertrophy, and reversion to a fetal myocardial gene expression program occurred in EgfrVel/+ mice with aortic valve dysfunction, but not in EgfrVel/+ mice with near-normal aortic valve function. Myocardial fibrosis was minimal or absent in all groups. CONCLUSIONS: A new mouse model uniquely recapitulates salient functional, structural, and histologic features of human unicuspid aortic valve disease, which are phenotypically distinct from other forms of congenital aortic valve disease. The new model may be useful for elucidating mechanisms by which congenitally anomalous aortic valves become critically dysfunctional.

Spontaneous Aortic Regurgitation and Valvular Cardiomyopathy in Mice.

OBJECTIVE: We studied the mechanistic links between fibrocalcific changes in the aortic valve and aortic valve function in mice homozygous for a hypomorphic epidermal growth factor receptor mutation (Wave mice). We also studied myocardial responses to aortic valve dysfunction in Wave mice. APPROACH AND RESULTS: At 1.5 months of age, before development of valve fibrosis and calcification, aortic regurgitation, but not aortic stenosis, was common in Wave mice. Aortic valve fibrosis, profibrotic signaling, calcification, osteogenic markers, lipid deposition, and apoptosis increased dramatically by 6 and 12 months of age in Wave mice. Aortic regurgitation remained prevalent, however, and aortic stenosis was rare, at all ages. Proteoglycan content was abnormally increased in aortic valves of Wave mice at all ages. Treatment with pioglitazone prevented abnormal valve calcification, but did not protect valve function. There was significant left ventricular volume overload, hypertrophy, and fetal gene expression, at all ages in Wave mice with aortic regurgitation. Left ventricular systolic function was normal until 6 months of age in Wave mice, but became impaired by 12 months of age. Myocardial transverse tubules were normal in the presence of left ventricular hypertrophy at 1.5 and 3 months of age, but became disrupted by 12 months of age. CONCLUSIONS: We present the first comprehensive phenotypic and molecular characterization of spontaneous aortic regurgitation and volume-overload cardiomyopathy in an experimental model. In Wave mice, fibrocalcific changes are not linked to valve dysfunction and are epiphenomena arising from structurally incompetent myxomatous valves.

Chronic vitamin K antagonist therapy and bleeding risk in ST elevation myocardial infarction patients.

OBJECTIVES: Acute management of ST elevation myocardial infarction (STEMI) patients on chronic vitamin K antagonist (VKA) therapy is uncertain. This study aims to estimate in-hospital major bleeding risk among STEMI patients on chronic VKA treated with primary percutaneous coronary intervention (PCI); and determine the relationship between bleeding and acute treatments stratified by international normalised ratio (INR) values. METHODS: We retrospectively examined 120,270 STEMI patients treated with primary PCI at 586 national registry hospitals (2007-2012). RESULTS: Overall, 3101 patients (2.6%) were on VKA which was associated with increased in-hospital major bleeding risk when compared with patients not on VKA (17.0%, vs 10.1%; adjusted OR 1.26, 95% CI 1.13 to 1.40). In patients on VKA, admission INR ≥2.0 was not associated with an increase in bleeding risk compared to INR <2.0. Patients on VKA were more likely to receive clopidogrel or bivalirudin within 24 h of presentation (acute), but less likely to receive prasugrel, heparin, or glycoprotein IIb/IIIa inhibitors (GPI). In those patients, acute GPI was associated with increased bleeding risk (adjusted OR 1.92, 95% CI 1.54 to 2.40) while bivalirudin was associated with decreased risk (adjusted OR 0.69, 95% CI 0.55 to 0.86); bleeding risk associated with heparin, bivalirudin, ADP-receptor blockers, or GPI was similar between INR ≥2.0 and <2.0. CONCLUSIONS: In STEMI patients treated with primary PCI, chronic VKA therapy was associated with a significant increase in in-hospital major bleeding risk compared to no VKA therapy, irrespective of whether admission INR was ≥2.0 or not. In patients on VKA, GPI was associated with increased bleeding risk while bivalirudin was associated with decreased risk.

Aortic valve sclerosis in mice deficient in endothelial nitric oxide synthase.

Risk factors for fibrocalcific aortic valve disease (FCAVD) are associated with systemic decreases in bioavailability of endothelium-derived nitric oxide (EDNO). In patients with bicuspid aortic valve (BAV), vascular expression of endothelial nitric oxide synthase (eNOS) is decreased, and eNOS(-/-) mice have increased prevalence of BAV. The goal of this study was to test the hypotheses that EDNO attenuates profibrotic actions of valve interstitial cells (VICs) in vitro and that EDNO deficiency accelerates development of FCAVD in vivo. As a result of the study, coculture of VICs with aortic valve endothelial cells (vlvECs) significantly decreased VIC activation, a critical early phase of FCAVD. Inhibition of VIC activation by vlvECs was attenuated by N(G)-nitro-l-arginine methyl ester or indomethacin. Coculture with vlvECs attenuated VIC expression of matrix metalloproteinase-9, which depended on stiffness of the culture matrix. Coculture with vlvECs preferentially inhibited collagen-3, compared with collagen-1, gene expression. BAV occurred in 30% of eNOS(-/-) mice. At age 6 mo, collagen was increased in both bicuspid and trileaflet eNOS(-/-) aortic valves, compared with wild-type valves. At 18 mo, total collagen was similar in eNOS(-/-) and wild-type mice, but collagen-3 was preferentially increased in eNOS(-/-) mice. Calcification and apoptosis were significantly increased in BAV of eNOS(-/-) mice at ages 6 and 18 mo. Remarkably, these histological changes were not accompanied by physiologically significant valve stenosis or regurgitation. In conclusion, coculture with vlvECs inhibits specific profibrotic VIC processes. In vivo, eNOS deficiency produces fibrosis in both trileaflet and BAVs but produces calcification only in BAVs.

Oxidized Ca(2+)/calmodulin-dependent protein kinase II triggers atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is a growing public health problem without adequate therapies. Angiotensin II and reactive oxygen species are validated risk factors for AF in patients, but the molecular pathways connecting reactive oxygen species and AF are unknown. The Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) has recently emerged as a reactive oxygen species-activated proarrhythmic signal, so we hypothesized that oxidized CaMKIIδ could contribute to AF. METHODS AND RESULTS: We found that oxidized CaMKII was increased in atria from AF patients compared with patients in sinus rhythm and from mice infused with angiotensin II compared with mice infused with saline. Angiotensin II-treated mice had increased susceptibility to AF compared with saline-treated wild-type mice, establishing angiotensin II as a risk factor for AF in mice. Knock-in mice lacking critical oxidation sites in CaMKIIδ (MM-VV) and mice with myocardium-restricted transgenic overexpression of methionine sulfoxide reductase A, an enzyme that reduces oxidized CaMKII, were resistant to AF induction after angiotensin II infusion. CONCLUSIONS: Our studies suggest that CaMKII is a molecular signal that couples increased reactive oxygen species with AF and that therapeutic strategies to decrease oxidized CaMKII may prevent or reduce AF.

Coronary collateral circulation: its relevance.

The interest in coronary collateral circulation (CCC) as "natural bypasses" is growing, especially in patients in whom the extent of coronary atherosclerosis is too severe to allow for conventional revascularization. The anatomic foundation of CCC has been recognized for long time. Recently, reliable methods have become available for the assessment of the adequacy of collateral flow. However, the debate regarding the importance of CCC in the different clinical settings continues. In this article, we present the recent progress in the understanding of anatomy and physiology of the CCC and focus on the studies addressing their functional significance in acute, subacute, and chronic coronary artery disease. In addition, we provide a focused update on the essential role of collateral circulation in the management of coronary chronic total occlusions.

Thalidomide and thrombosis. A meta-analysis.

With the increase in the number of reports and trials on the use of thalidomide as a part of the treatment of different medical conditions, particularly multiple myeloma (MM), it was observed that this drug might be associated with an increase in the risk of venous thromboembolic (VTE) events. It was the objective of this study to assess this risk, to check whether it might be affected by the concomitant administration of other medications, specifically dexamethasone, and to study the effect of anticoagulation and anti-platelet medications. A literature search for articles describing the use of thalidomide and the resultant VTE events was performed, and 50 articles were reviewed. A sample consisting of 3,322 patients resembling the above-mentioned studies was designed, and multivariate logistic regression was conducted. While thalidomide, dexamethasone and their combination were found to significantly increase the risk of VTE events among MM patients by 2.6, 2.8 and eight times, respectively, "adequate" anticoagulation significantly reduced the risk. In conclusion, patients receiving thalidomide should be carefully monitored for thromboembolic events, and those receiving concomitantly dexamethasone or other chemotherapy should be followed even more closely. Administering prophylactic doses of low-molecular-weight heparin or warfarin with therapeutic International Normalized Ratio reduces the risk of thromboembolic events among MM patients.