Circulating and tissue matricellular RNA and protein expression in calcific aortic valve disease.

Aortic valve sclerosis is a highly prevalent, poorly characterized asymptomatic manifestation of calcific aortic valve disease and may represent a therapeutic target for disease mitigation. Human aortic valve cusps and blood were obtained from 333 patients undergoing cardiac surgery (n = 236 for severe aortic stenosis, n = 35 for asymptomatic aortic valve sclerosis, n = 62 for no valvular disease), and a multiplex assay was used to evaluate protein expression across the spectrum of calcific aortic valve disease. A subset of six valvular tissue samples (n = 3 for asymptomatic aortic valve sclerosis, n = 3 for severe aortic stenosis) was used to create RNA sequencing profiles, which were subsequently organized into clinically relevant gene modules. RNA sequencing identified 182 protein-encoding, differentially expressed genes in aortic valve sclerosis vs. aortic stenosis; 85% and 89% of expressed genes overlapped in aortic stenosis and aortic valve sclerosis, respectively, which decreased to 55% and 84% when we targeted highly expressed genes. Bioinformatic analyses identified six differentially expressed genes encoding key extracellular matrix regulators: TBHS2, SPARC, COL1A2, COL1A1, SPP1, and CTGF. Differential expression of key circulating biomarkers of extracellular matrix reorganization was observed in control vs. aortic valve sclerosis (osteopontin), control vs. aortic stenosis (osteoprotegerin), and aortic valve sclerosis vs. aortic stenosis groups (MMP-2), which corresponded to valvular mRNA expression. We demonstrate distinct mRNA and protein expression underlying aortic valve sclerosis and aortic stenosis. We anticipate that extracellular matrix regulators can serve as circulating biomarkers of early calcific aortic valve disease and as novel targets for early disease mitigation, pending prospective clinical investigations.

Porphyrin-Based SOD Mimic MnTnBu OE -2-PyP5+ Inhibits Mechanisms of Aortic Valve Remodeling in Human and Murine Models of Aortic Valve Sclerosis.

Background Aortic valve sclerosis ( AVS c), the early asymptomatic presentation of calcific aortic valve (AV) disease, affects 25% to 30% of patients aged >65 years. In vitro and ex vivo experiments with antioxidant strategies and antagonists of osteogenic differentiation revealed that AVS c is reversible. In this study, we characterized the underlying changes in the extracellular matrix architecture and valve interstitial cell activation in AVSc and tested in vitro and in vivo the activity of a clinically approved SOD (superoxide dismutase) mimic and redox-active drug MnTnBu OE -2-PyP5+ ( BMX -001). Methods and Results After receiving informed consent, samples from patients with AVS c, AV stenosis, and controls were collected. Uniaxial mechanical stimulation and in vitro studies on human valve interstitial cells were performed. An angiotensin II chronic infusion model was used to impose AV thickening and remodeling. We characterized extracellular matrix structures by small-angle light scattering, scanning electron microscopy, histology, and mass spectrometry. Diseased human valves showed altered collagen fiber alignment and ultrastructural changes in AVS c, accumulation of oxidized cross-linking products in AV stenosis, and reversible expression of extracellular matrix regulators ex vivo. We demonstrated that MnTnBu OE -2-PyP5+ inhibits human valve interstitial cell activation and extracellular matrix remodeling in a murine model (C57 BL /6J) of AVS c by electron microscopy and histology. Conclusions AVS c is associated with architectural remodeling despite marginal effects on the mechanical properties in both human and mice. MnTnBu OE -2-PyP5+ controls AV thickening in a murine model of AVS c. Because this compound has been approved recently for clinical use, this work could shift the focus for the treatment of calcific AV disease, moving from AV stenosis to an earlier presentation ( AVS c) that could be more responsive to medical therapies.

Serotonin receptor 2B signaling with interstitial cell activation and leaflet remodeling in degenerative mitral regurgitation.

AIMS: Mitral valve interstitial cells (MVIC) play an important role in the pathogenesis of degenerative mitral regurgitation (MR) due to mitral valve prolapse (MVP). Numerous clinical studies have observed serotonin (5HT) dysregulation in cardiac valvulopathies; however, the impact of 5HT-mediated signaling on MVIC activation and leaflet remodeling in MVP have been investigated to a limited extent. Here we test the hypothesis that 5HT receptors (5HTRs) signaling contributes to MVP pathophysiology. METHODS AND RESULTS: Diseased human MV leaflets were obtained during cardiac surgery for MVP; normal MV leaflets were obtained from heart transplants. MV RNA was used for microarray analysis of MVP patients versus control, highlighting genes that indicate the involvement of 5HTR pathways and extracellular matrix remodeling in MVP. Human MV leaflets were also studied in vitro and ex vivo with biomechanical testing to assess remodeling in the presence of a 5HTR2B antagonist (LY272015). MVP leaflets from Cavalier King Charles Spaniels were used as a naturally acquired in vivo model of MVP. These canine MVP leaflets (N=5/group) showed 5HTR2B upregulation. This study also utilized CB57.1ML/6 mice in order to determine the effect of Angiotensin II infusion on MV remodeling. Histological analysis showed that MV thickening due to chronic Angiotensin II remodeling is mitigated by a 5HTR2B antagonist (LY272015) but not by 5HTR2A inhibitors. CONCLUSION: In humans, MVP is associated with an upregulation in 5HTR2B expression and increased 5HT receptor signaling in the leaflets. Antagonism of 5HTR2B mitigates MVIC activation in vitro and MV remodeling in vivo. These observations support the view that 5HTR signaling is involved not only in previously reported 5HT-related valvulopathies, but it is also involved in the pathological remodeling of MVP.

Bilateral internal mammary artery Y construct with multiple sequential grafting improves survival compared to bilateral internal mammary artery with additional vein grafts: 10-year experience at 2 different institutions†.

OBJECTIVES: Utilization of bilateral internal mammary arteries (BIMAs) has been shown to improve long-term outcomes in patients undergoing coronary artery bypass grafting. To achieve complete revascularization, BIMAs may be used as either sole conduits for revascularization through a Y-graft configuration (BIMA-Y) or deployed with additional grafts used in conjunction with BIMAs. The purpose of this study was to compare the long-term outcomes of two institutions that predominantly used either the BIMA-Y configuration or BIMA plus additional grafts to achieve optimal revascularization. METHODS: From 1 January 2000 to 31 December 2010, 436 patients were revascularized using a non-sequential BIMA grafting at one institution (Group A), with veins being used for additional targets. At the second institution (Group B), 771 patients were revascularized using a BIMA-Y graft for all distal targets. Kaplan­Meier analysis was used to compare unadjusted survival between the groups. Cox proportional hazards regression modelling was used to provide an adjusted comparison of survival between the groups. RESULTS: There was no statistically significant difference between the average number of anastomotic sites used in Group A and Group B (A = 4.0 ± 0.7 vs B = 4.0 ± 0.7; P = 0.24). Group A did not have a significantly greater in-hospital mortality (0.7% vs 1.0% P = 0.39), stroke (0.5% vs 0.8% P = 0.40), deep sternal wound infection (0.0% vs 0.6% P = 0.11) or reoperation for bleeding (1.6% vs 0.6% P = 0.10) than Group B. Cox proportional hazards analyses demonstrated that at 14 years, Group B had a significantly improved survival compared to Group A (Group B = 88% vs Group A = 81%) with an overall reduction in mortality (adjusted hazard ratio 0.780, 95% confidence interval 0.448­0.849; P = 0.043). CONCLUSION: Utilization of the BIMA-Y configuration was associated with improved survival when compared to BIMA grafting with additional vein grafts. Further studies are necessary to evaluate the efficacy of BIMA-Y grafting against other means of providing complete arterial revascularization.

Blood transfusion in cardiac surgery does increase the risk of 5-year mortality: results from a contemporary series of 1714 propensity-matched patients.

BACKGROUND: Studies have found that cardiac surgery patients receiving blood transfusions are at risk for increased mortality during the first year after surgery, but risk appears to decrease after the first year. This study compared 5-year mortality in a propensity-matched cohort of cardiac surgery patients. STUDY DESIGN AND METHODS: Between July 1, 2004, and June 30, 2011, 3516 patients had cardiac surgery with 1920 (54.6%) requiring blood transfusion. Propensity matching based on 22 baseline characteristics yielded two balanced groups (blood transfusion group [BTG] and nontransfused control group [NCG]) of 857 patients (1714 in total). The type and number of blood products were compared in the BTG. RESULTS: Operative mortality was higher in BTG versus NCG (2.3% vs. 0.4%; p < 0.0001). Kaplan-Meier analysis of 5-year survival demonstrated no difference between groups in the first 2 years (BTG 96.3% and 93.0% vs. NCG 96.4% and 93.9%, respectively). There was a significant divergence during Years 3 to 5 (BTG 82.0% vs. NCG 89.3% at 5 years; p < 0.007). Five-year survival was significantly lower in patients who received at least 2 units of blood (79.6% vs. 88.0%; p < 0.0001). In multivariate Cox regression analyses, transfusion was independently associated with increased risk for 5-year mortality. Patients receiving cryoprecipitate products had a twofold mortality risk increase (adjusted hazard ratio, 2.106; p = 0.002). CONCLUSION: Blood transfusion, specifically cryoprecipitates, was independently associated with increased 5-year mortality. Transfusion during cardiac surgery should be limited to patients who are in critical need of blood products.

Epicardial surgical ligation of the left atrial appendage is safe, reproducible, and effective by transesophageal echocardiographic follow-up.

OBJECTIVE: The left atrial appendage (LAA) is the source of 90% of thrombi in patients with atrial fibrillation. Our double LAA ligation (LLAA) technique was shown to be 96% successful in a small study. However, the outcomes of these patients have yet to be compared with a set of nonligated patients. METHODS: From 2005 to 2012, a total of 808 patients received LAA using our double ligation technique using both a polydioxanone (PDS) II endosnare and a running 4-0 Prolene pledgeted suture. The 30-day outcomes of these patients were compared with that of nonligated patients. Fifty-six of the ligated patients had a postoperative transesophageal echocardiography (TEE). An echocardiographer reviewed the follow-up TEEs for LAA remnant and/or residual flow into the LAA using color Doppler imaging. The patients with LAA flow and/or remnant depth of 1 cm or greater were deemed to have an unsuccessful exclusion. RESULTS: The ligated group had a trend of less postoperative atrial fibrillation (19.4% vs 22.9%, P = 0.07) and an overall significantly lower in-hospital mortality (0.7% vs 3.0%, P < 0.001) and lower 30-day mortality (0.7% vs 3.4%, P < 0.0001). The LAA was successfully excluded in 53 (94.7%) of the 56 patients with TEE. CONCLUSIONS: Double LAA ligation correlates with lower rates of in-hospital and 30-day mortality. This advantage comes without an increase in perioperative complications. This technique can easily be performed off or on pump, is very reproducible, and comes at a very low cost compared with LAA occlusion devices. Stroke has a multifactorial etiology; successful LLAA removes one potential source of thrombi perioperatively and in the long-term.

Balancing the benefits and risks of blood transfusions in patients undergoing cardiac surgery: a propensity-matched analysis.

OBJECTIVES: Prior studies have found that cardiac surgery patients receiving blood transfusions are at risk for increased mortality and morbidity following surgery. It is not clear whether this increased risk occurs across all haematocrit (HCT) levels. The goal of this study was to compare operative mortality in propensity-matched cardiac surgery patients based on stratification of the preoperative HCT levels. METHODS: Between 1 August 2004 and 30 June 2011, 3516 patients had cardiac surgery. One thousand nine hundred and twenty-two (54.5%) required blood transfusion during or after surgery. A propensity score for transfusion was developed based on 22 baseline variables. One thousand seven hundred and fourteen patients were matched: 857 in the transfusion group (TG) and 857 in the non-transfused control group (CG). Univariate analyses demonstrated that, after propensity matching, the groups did not differ on any baseline factors included in the propensity model. Operative mortality was defined as death within 30 days of surgery. Preoperative HCT was stratified into four groups: <36, 36-39, 40-42 and ≥ 43. RESULTS: For HCT <36%, 30-day mortality was higher in the TG than that in the CG (3.0 vs 0.0%). For HCT 36-39, operative mortality was similar between TG (1.1%, N = 180) and CG (0.8%, N = 361; P = 0.748). For HCT 40-42, operative mortality was significantly higher in the TG compared with that in the CG (1.9 vs 0%, N = 108 and 218, respectively; P = 0.044). For HCT of ≥ 43, there was a trend towards higher operative mortality in the TG vs the CG (2.0 vs 0%, N = 102 and 152, respectively; P = 0.083). Other surgical complications followed the same pattern with higher rates found in the transfused group at higher presurgery HCT levels. HCT at discharge for the eight groups were similar, with an average of 29.1 ± 1.1% (P = 0.117). CONCLUSIONS: Our study indicates that a broad application of blood products shows no discernible benefits. Furthermore, patients who receive blood at all HCT levels may be placed at an increased risk of operative mortality and/or other surgical complications. Paradoxically, even though patients with low HCTs theoretically should benefit the most, transfusion was still associated with a higher complication and mortality rate in these patients. Our results indicate that blood transfusion should be used judiciously in cardiac surgery patients.