Cardiac Microvascular Endothelial Cells in Pressure Overload-Induced Heart Disease.

BACKGROUND: Chronic pressure overload predisposes to heart failure, but the pathogenic role of microvascular endothelial cells (MiVEC) remains unknown. We characterized transcriptional, metabolic, and functional adaptation of cardiac MiVEC to pressure overload in mice and patients with aortic stenosis (AS). METHODS: In Tie2-Gfp mice subjected to transverse aortic constriction or sham surgery, we performed RNA sequencing of isolated cardiac Gfp+-MiVEC and validated the signature in freshly isolated MiVEC from left ventricle outflow tract and right atrium of patients with AS. We next compared their angiogenic and metabolic profiles and finally correlated molecular and pathological signatures with clinical phenotypes of 42 patients with AS (50% women). RESULTS: In mice, transverse aortic constriction induced progressive systolic dysfunction, fibrosis, and reduced microvascular density. After 10 weeks, 25 genes predominantly involved in matrix-regulation were >2-fold upregulated in isolated MiVEC. Increased transcript levels of Cartilage Intermediate Layer Protein (Cilp), Thrombospondin-4, Adamtsl-2, and Collagen1a1 were confirmed by quantitative reverse transcription polymerase chain reaction and recapitulated in left ventricle outflow tract-derived MiVEC of AS (P<0.05 versus right atrium-MiVEC). Fatty acid oxidation increased >2-fold in left ventricle outflow tract-MiVEC, proline content by 130% (median, IQR, 58%-474%; P=0.008) and procollagen secretion by 85% (mean [95% CI, 16%-154%]; P<0.05 versus right atrium-MiVEC for all). The altered transcriptome in left ventricle outflow tract-MiVEC was associated with impaired 2-dimensional-vascular network formation and 3-dimensional-spheroid sprouting (P<0.05 versus right atrium-MiVEC), profibrotic ultrastructural changes, and impaired diastolic left ventricle function, capillary density and functional status, especially in female AS. CONCLUSIONS: Pressure overload induces major transcriptional and metabolic adaptations in cardiac MiVEC resulting in excess interstitial fibrosis and impaired angiogenesis. Molecular rewiring of MiVEC is worse in women, compromises functional status, and identifies novel targets for intervention.

A randomized assessment of an advanced tissue preservation technology in the juvenile sheep model.

BACKGROUND: Despite improved anticalcification technology, bioprosthetic heart valves still cannot be used in younger patients because of progressive structural valve degeneration. A novel advanced tissue preservation technology was developed that uses stable functional group capping and preservation by glycerolization. Valves incorporating this novel technology can be stored in a dry condition and do not require rinsing before use. The aim of the study was to assess the effects of this new technology in terms of valve function and durability in a chronic sheep model of orthotopic implantation. METHODS: Forty-five juvenile sheep were randomized and either a Perimount mitral valve (6900P, control group) or the same valve design incorporating the novel tissue preservation technology (test group) was implanted in the mitral position. All valves were 25 mm. A transthoracic echocardiography was performed at 1 week and at 8 months postoperatively. The animals were then killed, an autopsy was performed, and the valves were examined radiographically (soft tissue radiograph), histologically (hematoxylin and eosin and Von Kossa staining), and chemically (calcium content). Exclusion criteria for analysis included surgical or procedural death, bacterial endocarditis or other diseases leading to premature death. RESULTS: Thirty-one animals (14 controls and 17 test animals) remained in perfect condition during the 8-month follow-up period. Echocardiography at 1 week showed normal valve function in both groups. At 8 months, cardiac output increased significantly to the same extent in both groups (vs baseline; P < .01). The mean transvalvular pressure gradient also increased but significantly more in the control group compared with the test group (P = .03). Flow turbulence across the prosthesis was increased in the control valves compared with the test valves. The test valves had significantly less calcium content than the controls (1.9 ± 0.3 vs 6.8 ± 1.6 µg/mg; P = .002). This was confirmed by radiographic analysis and histology. CONCLUSIONS: This study demonstrates that the novel tissue preservation technology, when applied to the Perimount mitral valve, significantly improves hemodynamic and anticalcification properties compared with the standard Perimount, a valve currently considered the standard of care.

Murine pressure overload models: a 30-MHz look brings a whole new "sound" into data interpretation.

Transverse aortic constriction (TAC) and angiotensin II (ANG II) subcutaneous osmotic pump infusion are frequently used murine models of pressure overload hypertrophy. The aim of this paper is to investigate time- and stressor-dependent functional and structural changes using echocardiographic B-mode, M-mode, and Doppler characterization. Ten-week-old male C57BL6/J wild-type mice received 4-wk ANG II (1.5 mg·kg(-1)·day(-1), n = 19) or saline (n = 10) infusion followed by echocardiography (Vevo2100, Visual Sonics), or underwent TAC (n = 63) or a sham operation (n = 30). In the TAC protocol, echocardiography was performed after 2 wk (n = 22 TAC, n = 10 sham), after 4 wk (n = 20 TAC, n = 10 sham), and after 10 wk (n = 21 TAC, n = 10 sham). ANG II infusion was associated with a mixed pressure and volume overload, with a variable contribution of volume overload caused by aortic valve insufficiency (grade 0.5-3.5/4). The degree of aortic valve insufficiency correlated with the degree of left ventricular dilation (r(2) = 0.671, P < 0.001). After TAC, all hypertrophic remodeling patterns known in human disease were observed: 1) low-flow, low-gradient with preserved ejection fraction (EF); 2) concentric hypertrophy with normal EF and flow; 3) concentric hypertrophy with moderately decreased EF and/or flow; 4) eccentric hypertrophy with normal EF and flow; 5) eccentric hypertrophy with moderately decreased EF and/or flow; and 6) eccentric hypertrophy with severely depressed EF. Eccentric remodeling was time dependent, with 5% of mice developing this phenotype at 2 wk, 39% at 4 wk, and 59% at 10 wk. Comprehensive echocardiographic analysis allows identification of homogeneous subgroups of mice subjected to hypertrophic stress, reducing variability in experimental results and facilitating clinical translation.

Coating with fibronectin and stromal cell-derived factor-1α of decellularized homografts used for right ventricular outflow tract reconstruction eliminates immune response-related degeneration.

OBJECTIVE: This study assesses the performance and cellular features of decellularized ovine aortic homografts coated with stromal cell-derived factor-1α (SDF-1α) and its natural linker, fibronectin (FN), after implantation in the right ventricular outflow tract of adolescent sheep. METHODS: Right ventricular outflow tract reconstructions using cryopreserved (n = 7), decellularized (n = 8), and decellularized FN/SDF-1α-coated aortic ovine homografts (n = 6) were performed. Echocardiographic, morphologic, radiographic, histologic, and immunohistochemical examinations were performed 5 months after implantation. RESULTS: There were no hemodynamic differences between groups, except for the decellularized homografts' tendency to develop more valve regurgitation (3 of 8 grafts had regurgitation >2/4). All decellularized, but coated, grafts had normal hemodynamics. Decellularized valve conduits were less calcified than cryopreserved conduits (P < .05), but coated valve conduits were free of calcification (P < .05). The same was found for pannus in the outflow parts. Immune response (CD45(+), CD45R(+), or CD11b(+) cells) was decreased in decellularized valves compared with cryopreserved grafts, but was virtually absent (P < .05) in coated grafts. Collagen organization and density in the leaflets and walls were decreased in cryopreserved and decellularized valves, but not in coated valves (P < .05). Coating improved re-endothelialization (P < .05). CONCLUSIONS: Coating of decellularized allografts with FN/SDF-1α prevents cryopreserved heart valve-mediated immune response, conduit calcification, and pannus formation and stimulates re-endothelialization.

Increased cardiac myocyte PDE5 levels in human and murine pressure overload hypertrophy contribute to adverse LV remodeling.

BACKGROUND: The intracellular second messenger cGMP protects the heart under pathological conditions. We examined expression of phosphodiesterase 5 (PDE5), an enzyme that hydrolyzes cGMP, in human and mouse hearts subjected to sustained left ventricular (LV) pressure overload. We also determined the role of cardiac myocyte-specific PDE5 expression in adverse LV remodeling in mice after transverse aortic constriction (TAC). METHODOLOGY/PRINCIPAL FINDINGS: In patients with severe aortic stenosis (AS) undergoing valve replacement, we detected greater myocardial PDE5 expression than in control hearts. We observed robust expression in scattered cardiac myocytes of those AS patients with higher LV filling pressures and BNP serum levels. Following TAC, we detected similar, focal PDE5 expression in cardiac myocytes of C57BL/6NTac mice exhibiting the most pronounced LV remodeling. To examine the effect of cell-specific PDE5 expression, we subjected transgenic mice with cardiac myocyte-specific PDE5 overexpression (PDE5-TG) to TAC. LV hypertrophy and fibrosis were similar as in WT, but PDE5-TG had increased cardiac dimensions, and decreased dP/dtmax and dP/dtmin with prolonged tau (P<0.05 for all). Greater cardiac dysfunction in PDE5-TG was associated with reduced myocardial cGMP and SERCA2 levels, and higher passive force in cardiac myocytes in vitro. CONCLUSIONS/SIGNIFICANCE: Myocardial PDE5 expression is increased in the hearts of humans and mice with chronic pressure overload. Increased cardiac myocyte-specific PDE5 expression is a molecular hallmark in hypertrophic hearts with contractile failure, and represents an important therapeutic target.

Antithrombotic therapy in patients with heart valve prostheses.

Heart valve prostheses carry a risk for thrombosis and require an antithrombotic strategy to prevent stroke, systemic embolism, and prosthetic valve thrombosis. Contemporary randomized trials to guide the clinician on the optimal anticoagulant treatment are scarce, and the validity of the historical data for current recommendations can be questioned in view of the changes in valve prostheses, the patient population, and antithrombotic therapies. This limited evidence from clinical trials translates into divergent recommendations from the different scientific societies on the optimal intensity of oral anticoagulation and on the indication for antiplatelet therapy. The availability of new antithrombotic agents and the unclear thrombotic risk of the currently used prostheses underscore the need to redefine antithrombotic treatment in patients with heart valve prostheses.

Mitral annuloplasty for dilated cardiomyopathy with mitral regurgitation.

OBJECTIVES: This study reports survival, functional status, the change in post-operative left ventricular dimensions and function after'undersized mitral annuloplasty' in patients with non-ischaemic non-valvular dilated cardiomyopathy and secondary mitral regurgitation. PATIENTS AND METHODS: Between 2003 and 2009 10 patients (mean age 61.5 +/- 14 years) with non-ischaemic, non-valvular dilated cardiomyopathy with left ventricular ejection fraction (LV EF) <40% (mean +/- SD, 30.7 +/- 5.27) underwent isolated mitral repair and annuloplasty. All patients were receiving maximal drug therapy. Preoperatively 1 patient (10%) was functioning in New York Heart Association (NYHA) class II, 8 patients (80%) in class III and 1 patient (10%) in class IV. Transthoracic echocardiography was performed immediately before surgery and one year after surgery to assess valvular and ventricular function. For statistical analysis we have used paired t-tests and Wilcoxon's rank test. RESULTS: There were no hospital deaths. Duration of intubation and ICU stay was 1.8 +/- 1.3 and 3.8 +/- 1.8 days, respectively. Functional class after one year was significantly better than the preoperative value (from 3.00 +/- 0.47 to 1.40 +/- 0.52, P<0.001). One year post-operative data showed significant improvement of LV EF (from 30.70 +/- 5.27 to 46.60 +/- 14.47%) and a decrease of the left ventricular diastolic dimension (LVDd) (from 59.30 +/- 5.62 to 50.70 +/- 6.04 mm). CONCLUSION: Isolated undersized mitral annuloplasty in patients with non-ischaemic non-valvular dilated cardiomyopathy with associated mitral regurgitation, is a safe method with the potential of improving functional class, LV EF, and LVDd after one year.

Effect of sutureless implantation of the Perceval S aortic valve bioprosthesis on intraoperative and early postoperative outcomes.

OBJECTIVE: Prolonged aortic crossclamping can increase mortality and morbidity after aortic valve replacement in elderly and high-risk patients. Sutureless implantation of the prosthesis has the potential to shorten aortic crossclamp time. METHODS: The Perceval S valve (Sorin Biomedica Cardio Srl, Sallugia, Italy), a sutureless implantable aortic bioprosthesis, was used in 32 patients (median age, 78 years; median logistic euroSCORE, 9.99) requiring aortic valve replacement with or without concomitant coronary artery bypass grafting. Hemodynamic parameters and clinical outcome were obtained at discharge, at 6 months, and up to 1 year postoperatively. RESULTS: Aortic crossclamp time needed for aortic valve replacement was 18 ± 6 minutes. Hemodynamics at discharge showed good function of all Perceval S valves with low transvalvular pressure gradients (mean, 12 ± 5 mm Hg and peak, 23 ± 9 mm Hg) and low incidence of paravalvular or valvular leakage. Operative mortality was 0%. Follow-up at 1 year showed 3 non-valve-related deaths. Survivors showed good clinical outcome and stable hemodynamic function of the valve prosthesis, except for 1 patient in whom endocarditis developed. Despite a moderate decrease in platelet counts persisting up to 12 months, freedom of bleeding and thromboembolic events was 100%. CONCLUSIONS: It is possible to implant a well-functioning sutureless stent-mounted valve in the aortic position in less than 20 minutes of aortic crossclamping. This is associated with excellent early clinical and hemodynamic outcome in high-risk patients. Moderate changes in hematologic parameters persisted but were not related to clinical events.

Mid-term follow up of triple valve surgery in a western community: predictors of survival.

BACKGROUND AND AIM OF THE STUDY: Triple valve surgery remains a challenge, although with an improved survival rate compared to historical data. Aws assessment was made as to whether the type of valve surgery, underlying valve lesion and pathology were independent predictors of outcome. The patient characteristics were also described according to the type of surgery performed. METHODS: A total of 166 consecutive patients underwent triple valve surgery and were followed up between October 1972 and June 2006. The clinical and operative variables were obtained retrospectively by physicians. The median follow up was 6.11 years (interquartile range 2.13-10.43). RESULTS: The overall 30-day mortality was 10%, five-year survival 70%, and 10-year survival 60%. In patients with three mechanical valves, survival at five years was 90%, and 85% at 10 years, compared to 40% at five years and 30% at 10 years in patients with three bioprostheses. Among all patients with a mechanical valve in the aortic and mitral positions, those with a tricuspid bioprosthesis were compared to patients with tricuspid repair. The survival rate at 10 years was 60%, and similar between groups. The survival rate of patients with aortic and mitral bioprostheses and tricuspid repair was comparable to that in patients with three bioprostheses. Multivariable analyses showed that the type of tricuspid surgery, age, and NYHA functional class were each significant and independent predictors of survival, with a tricuspid mechanical prosthesis favoring survival. According to the type of surgery, the patient groups differed in their cardiovascular and non-cardiovascular risk profiles. CONCLUSION: Triple-valve surgery is a difficult procedure, with greatly improved survival rates compared to historically reported data. The decision of prosthetic valve type and repair should be tailored to the individual patient, as both patient characteristics and chosen surgery appear to determine survival and morbidity. In young patients, a mechanical prosthesis should also be considered in the tricuspid position.

Statins for calcific aortic valve stenosis: into oblivion after SALTIRE and SEAS? An extensive review from bench to bedside.

Calcific aortic stenosis is the most frequent heart valve disease and the main indication for valve replacement in western countries. For centuries attributed to a passive wear and tear process, it is now recognized that aortic stenosis is an active inflammatory and potentially modifiable pathology, with similarities to atherosclerosis. Statins were first-line candidates for slowing down progression of the disease, as established drugs in primary and secondary cardiovascular prevention. Despite promising animal experiments and nonrandomized human trials, the prospective randomized trials SEAS and SALTIRE did not confirm the expected benefit. We review SEAS and SALTIRE starting with the preceding studies and discuss basic science experiments covering the major known contributors to the pathophysiology of calcific aortic valve disease, to conclude with a hypothesis on the absent effect of statins, and suggestions for further research paths.