Clinical Durability of the CARMEDA BioActive Surface in EXCOR Ventricular Assist Device Pumps.

The durability of CBAS Heparin Surface on EXCOR pumps retrieved after clinical use for varying periods of time was studied by analyzing samples for surface heparin density and bioactivity. The mean time of clinical use of the investigated 14 EXCOR pumps was 178 days (range, 15-461 days). Mean heparin density was 3.1 ± 0.6 µg/cm² (range, 2.2-4.8 µg/cm²), and the measured mean heparin bioactivity was 14 ± 5 ρmol/cm² (range: 7-27 ρmol/cm²). There was no detectable degradation or loss of function of CBAS Heparin Surface over time. Samples from the housing and the membrane of the EXCOR pump showed no significant difference in heparin bioactivity or density. The CBAS Heparin Surface stays on the surface and remains bioactive on the EXCOR pump at least up until 1 year. This is an important demonstration of coating durability and supports the mid-term and long-term clinical use as bridge-to-heart transplantation or to myocardial recovery.

Dietary plant stanols or sterols neither accumulate in stenotic aortic valves nor influence their structure or inflammatory status.

BACKGROUND & AIMS: Consumption of plant stanols and plant sterols decreases LDL cholesterol level and increases serum concentrations of plant stanols/sterols, but it is practically unexplored whether also their tissue concentrations increase. Thus, the aim of this study was to assess whether consuming plant stanols/sterols increases their concentrations in stenotic aortic valves and affect the valvular structure (collagen and elastin) or inflammation (macrophages and mast cells). METHODS: In a randomized, double-blind controlled intervention patients with severe aortic stenosis consumed margarine without (n = 11) or with 2 g of plant stanols (n = 12) or sterols (n = 13) until valve replacement surgery (2.6 months, on average). The effects of sitostanol and sitosterol on the expression and secretion of proinflammatory cytokines by cultured aortic valve myofibroblasts were also assessed. RESULTS: Control-related LDL-cholesterol was diminished by 16% (p < 0.05) by plant stanol and by 11% (NS) by plant sterol consumption, respectively. In the resected valves, cholesterol, plant stanol and sterol levels were similar in all groups. Consumed plant stanols or sterols had no effect on valvular structure or mast cell or macrophage numbers in valves. Incubation of cultured myofibroblasts derived from stenotic valves with sitostanol or sitosterol decreased mRNA expression of the monocyte chemotactic protein-1 (p < 0.05) and interleukin-1 beta (p < 0.05). CONCLUSIONS: In this study, plant stanol/sterol consumption did not affect cholesterol, plant stanol or sterol levels in stenotic aortic valves; neither did they influence the structure or the inflammatory status of the valves. However, these findings need to be confirmed in a larger-scale intervention. ClinicalTrials.govRegister #NCT00738933.

Is blockade of the Renin-Angiotensin system able to reverse the structural and functional remodeling of the left ventricle in severe aortic stenosis?

: In experimental aortic stenosis (AS), blockade of the renin-angiotensin system attenuates AS-related left ventricular (LV) dysfunction and improves survival. We tested whether candesartan, an angiotensin II type 1 receptor blocker, favorably influences LV structure and function and improves exercise capacity in AS patients. Fifty-one patients with severe AS were randomized to receive candesartan (target dose 16 mg/d) or placebo. Eight patients discontinued treatment and the remaining 43 patients underwent echocardiography, walking test, and measurement of plasma N-terminal B-type natriuretic peptide (Nt-proBNP) before and after an average of 5-month treatment. No statistically significant changes in LV diameters, mass, or function were seen. The median 6-minute walking distance decreased from 390 to 368 m with candesartan (P = 0.003) and from 380 to 370 m with placebo (P = 0.523), reflecting natural progression of AS. Concomitantly, median Nt-proBNP increased from 319 to 414 ng/L with candesartan (P = 0.170) and from 413 to 561 ng/L with placebo (P = 0.035). No change with candesartan was statistically significantly different from the corresponding change with placebo. In conclusion, candesartan was well tolerated but had no favorable effects on the LV or effort tolerance. The benefits found in experimental AS of blocking the renin-angiotensin system could not be reproduced in patients with severe AS.

Modified lipoprotein-derived lipid particles accumulate in human stenotic aortic valves.

In aortic stenosis plasma lipoprotein-derived lipids accumulate in aortic valves. Here, we first compared the lipid compositions of stenotic aortic valves and atherosclerotic plaque cores. Both pathological tissues were found to be enriched in cholesteryl linoleate, a marker of extracellularly accumulated lipoproteins. In addition, a large proportion of the phospholipids were found to contain arachidonic acid, the common precursor of a number of proinflammatory lipid mediators. Next, we isolated and characterized extracellular lipid particles from human stenotic and non-stenotic control valves, and compared them to plasma lipoproteins from the same subjects. The extracellular valvular lipid particles were isolated from 15 stenotic and 14 non-stenotic aortic valves. Significantly more apoB-100-containing lipid particles were found in the stenotic than in the non-stenotic valves. The majority of the lipid particles isolated from the non-stenotic valves had sizes (23±6.2 nm in diameter) similar to those of plasma low density lipoprotein (LDL) (22±1.5 nm), while the lipid particles from stenotic valves were not of uniform size, their sizes ranging from 18 to more than 500 nm. The lipid particles showed signs of oxidative modifications, and when compared to isolated plasma LDL particles, the lipid particles isolated from the stenotic valves had a higher sphingomyelin/phosphatidylcholine -ratio, and also higher contents of lysophosphatidylcholine and unesterified cholesterol. The findings of the present study reveal, for the first time, that in stenotic human aortic valves, infiltrated plasma lipoproteins have undergone oxidative and lipolytic modifications, and become fused and aggregated. The generated large lipid particles may contribute to the pathogenesis of human aortic stenosis.

Circulating collagen metabolites, myocardial fibrosis and heart failure in aortic valve stenosis.

BACKGROUND AND AIM OF THE STUDY: Myocardial fibrosis predisposes to heart failure in aortic valve stenosis. The study aim was to determine the value of: (i) circulating collagen metabolites as biomarkers of left ventricular fibrosis and heart failure in aortic stenosis; and (ii) myocardial fibrosis as a predictor of postoperative outcome. METHODS: Among a total of 132 patients (mean age 68 +/- 10 years) with severe aortic stenosis, measurements were made of circulating N-terminal propeptide of procollagen I (PINP), C-terminal telopeptide of collagen I (CITP) and N-terminal propeptide of procollagen III (PIIINP). Cardiac catheterization, echocardiography and a 6-min walk test were also performed. The aorta-to-coronary sinus concentration gradients of collagen metabolites were determined in 45 patients. Patients free from coronary artery disease (n = 85) underwent left ventricular biopsies for the assessment of myocardial fibrosis, one-year postoperative echocardiography and a 6-min walk test, and a long-term follow up for mortality. RESULTS: Neither peripheral collagen metabolites nor their transcardiac concentration gradients correlated with the extent of myocardial fibrosis. PIIINP demonstrated a net release from the heart, while PINP and CITP showed consistent falls in transcardiac concentrations that suggested extraction rather than release by the heart. Peripheral PIIINP correlated directly with the pulmonary wedge pressure (r = 0.50, p < 0.001) and inversely with the left ventricular ejection fraction (r = -0.40, p = 0.00001) and 6-min walk (r = -0.29, p = 0.001). Similar associations with heart failure were found for CITP, but not for PINP. One-year postoperative changes in exercise capacity and left ventricular mass and function were independent of myocardial fibrosis, as was mortality over a median of 8.8 years. CONCLUSION: Circulating collagen metabolites are not reliable surrogate measures of myocardial fibrosis in aortic stenosis, despite CITP and PIIINP being associated strongly with heart failure and left ventricular dysfunction. The results of surgery, including long-term survival, appear independent of the extent of myocardial fibrosis.

Comparison of the novel Medtentia double helix mitral annuloplasty system with the Carpentier-Edwards Physio annuloplasty ring: morphological and functional long-term outcome in a mitral valve insufficiency sheep model.

BACKGROUND: The prevalence of mitral regurgitation in cardiac diseases requires annuloplasty systems that can be implanted without excessive patient burden. This study was designed to examine the morphological and functional outcome of a new double helix mitral annuloplasty ring in an ovine model in comparison to the classical Carpentier-Edwards (CE) annuloplasty ring as measured by reduction of mitral regurgitation and tissue integration. The Medtentia annuloplasty ring (MAR) is a helical device that is rotated into the annulus self-restoring the valve geometry, enabling a faster fixation without the need of elaborate repair of the valve geometry. The ventricular part of the helical ring encircles the valve chords. METHODS: Twenty adult sheep were overpaced until 2+ level mitral valve regurgitation was achieved. Seven animals per group received either the MAR or the CE ring. Implantation was performed on-pump in a beating heart through the left atrial appendix. The animals were sacrificed 3.6 ± 0.3 months after surgery following an echocardiography for assessing mitral regurgitation as primary endpoint. The annuloplasty rings with surrounding tissue were harvested for histological analyses as secondary endpoints. The remaining six sheep received the MAR system and were sampled seven, nine or 12 months after surgery. RESULTS: Implantation time (p < 0.01) and perfusion time (p < 0.001) as clinical secondary endpoints were significantly shorter in the MAR group. Echocardiography follow-ups showed sufficient valve function repair in nearly all animals with a normalization of the ventricle diameters in both groups (group difference: p = 0.147). The weights of the hearts did not differ significantly. Histology revealed adequately covered atrial annuloplasty rings with functional endothelium and lack of excessive granulation tissue or fibrosis in all specimens. The ventricular projections of the MAR systems encircling the chordae tendineae were not completely covered with neointimal tissue, although in no case were microthrombi detected and no thromboembolic events were recorded. CONCLUSIONS: The new MAR system is an easy to use annuloplasty system with a functional outcome comparable to that of the well-proven CE ring. Mitral valve regurgitation is effectively stopped both by restricting the pathological expansion of the annulus and by gathering the chords without thrombus formation.

Microwave Ablation in Mitral Valve Surgery for Atrial Fibrillation (MAMA).

Objective: Microwave ablation in conjunction with open heart surgery is effective in restoring sinus rhythm (SR) in patients with atrial fibrillation (AF). In patients assigned for isolated mitral valve surgery no prospective randomized trial has reported its efficacy. Methods: 70 patients with longlasting AF where included from 5 different centres. They were randomly assigned to mitral valve surgery and atrial microwave ablation or mitral valve surgery alone. Results: Out of 70 randomized, 66 and 64 patients were available for evaluation at 6 and 12 months. At 12 months SR was restored and preserved in 71.0 % in the ablation group vs 36.4 % in the control group (P=0.006), corresponding figures at 6 months was 62.5 % vs 26.5 % (P=0.003). The 30-day mortality rate was 1.4 %, with one death in the ablation group vs zero deaths in the control group. At 12 months the mortality rate was 7,1 % (Ablation n=3 vs Control n=2). No significant differences existed between the groups with regard to the overall rate of serious adverse events (SAE) during the perioperative period or at the end of the study. 16 % of patients randomized to ablation were on antiarrhytmic drugs compared to 6 % in the control group after 1 year (p=0.22). Conclusion: Microwave ablation of left and right atrium in conjunction with mitral valve surgery is safe and effectively restores sinus rhythm in patients with longlasting AF as compared to mitral valve surgery alone.

Clinical value of intra-operative transit-time flow measurement for coronary artery bypass grafting: a prospective angiography-controlled study.

OBJECTIVE: Transit-time flow measurement (TTFM) is the most widely used method for intra-operative graft quality control in coronary artery bypass surgery. Although it may provide the opportunity for the surgeon to promptly revise the graft before the patient is discharged from the operating room, controlled clinical data on the ultimate usefulness of the TTFM are scarce. Clear cut-off values for when to revise grafts have not been set. METHODS: A total of 204 consecutive grafts (left internal mammary artery (n=46), vein graft (n=155), and radial artery (n=3)) underwent TTFM in 75 elective coronary artery bypass grafting (CABG) patients. The following parameters were recorded: mean graft flow (MGF), pulsatility index (PI), and insufficiency ratio (IR). After a mean follow-up of 199 ± 42 days, coronary angiography was performed for assessment of graft patency. RESULTS: A total of 166 grafts were found to be patent (85%), and 29 (15%) were completely occluded. The median and interquartile range (IQR) of MGF for the occluded grafts at the time of surgery was 38 ml min(-1) (IQR, 2549 ml min(-1)) and for the patent grafts 45 ml min(-1) (IQR, 31-71 ml min(-1); p=ns]. The corresponding PI values were 3.3 (IQR, 2.8-5.0) and 2.2 (IQR, 1.7-3.2; p=0.003), and the IR values were 1.6 (IQR, 0.6-6.1) and 0.2 (IQR, 0-2.2; p=0.03). By receiver operating characteristic (ROC) analysis, the highest sensitivity (72%) and specificity (70%) were associated with a PI value>3.0. However, 49 out of 70 such grafts (70%) were found to be patent. Furthermore, 10 out of 16 (63%) grafts, that had a combination of low flow (MGF<15 ml min(-1)) and high PI (>3.0), were patent at control angiography. CONCLUSIONS: TTFM predicts graft failure within the 6 months after CABG. However, specific cut-off recommendations for when to revise a graft cannot be set on the basis of TTFM. The cut-off values suggested in the literature lead to unnecessary graft revisions in the majority of cases, and, on the other hand, many technical defects probably remain unnoticed. Better methods to assess the quality of coronary artery bypass grafts are needed.

European multicenter study with the Soprano valve for aortic valve replacement: one-year clinical experience and hemodynamic data.

BACKGROUND AND AIM OF THE STUDY: During recent years, pericardial bioprostheses have gained widespread acceptance as cardiac valve substitutes. The study aim was to evaluate the early clinical and hemodynamic performance of the Sorin SopranoTM supra-annular aortic bioprosthesis, as used for aortic valve replacement (AVR). METHODS: Between January 2004 and August 2006, a total of 501 patients (55% males; mean age 75 +/- 6.4 years) was prospectively enrolled into the study, which involved 10 European institutions. The indications for AVR were aortic stenosis in 91% of patients, aortic incompetence in 8%, and redo surgery in 1%. Preoperatively, 62% of the patients were in NYHA class III, and 12% in class IV. The mean prosthesis size was 21.4 +/- 1.8 mm. A non-everting technique was used in 88% of patients. Concomitant procedures were performed in 52% of cases (mainly coronary artery bypass grafts; 41%). The mean cross-clamp and cardiopulmonary bypass times were 70 +/- 27.2 min and 99 +/- 39.7 min, respectively. Doppler echocardiography performed at one and 12 months after surgery was evaluated by an independent core laboratory. RESULTS: Postoperatively, there were 25 early deaths (5%) and 13 late deaths, with an overall survival at one year of 92.9% (95% CI: 90.2-94.8) and freedom from valve-related death of 98.6% (95% CI: 97.5-99.6). After 12 months, most patients (87%) were in NYHA classes I-II. Actuarial freedoms from thromboembolism, bleeding, endocarditis and paraprosthetic leak at one year were 97.1% (CI: 95.1-98.2), 98.9% (CI: 97.4-99.5), 99.1% (CI: 97.7-99.7), and 99.6% (CI: 98.3-99.9), respectively. No events of thrombosis and structural valve deterioration (SVD) were observed. Subsequent echocardiographic evaluation showed low mean (11.1 +/- 5.1 mmHg at one year) and peak (19.5 +/- 8.9 mmHg at one year) transvalvular gradients, and a significant reduction in left ventricular mass, from 211 +/- 78.5 g at one month to 185 +/- 64.7 g at 12 months (p <0.0001). CONCLUSION: After 12 months, the clinical outcome with the Soprano bioprosthesis, when used for AVR, was excellent. The bioprosthesis also showed good hemodynamic performance, with a significant reduction of left ventricular hypertrophy.

Medtentia double helix mitral annuloplasty system evaluated in a porcine experimental model.

OBJECTIVE: : To further develop and improve minimally invasive surgical procedures, dedicated appropriate surgical devices are mandatory. In this study, the safety and feasibility of implanting the novel Medtentia double helix mitral annuloplasty ring, which uses the key-ring principle to potentially allow faster and sutureless implantation, was assessed using both minimally invasive and conventional surgical techniques. Because of ethical concerns, a human compatible porcine experimental model of mitral valve surgery was used. METHODS: : Twelve 50-kg pigs were allocated to implantation of the Medtentia double helix annuloplasty ring using conventional midline sternotomy including cardioplegic arrest or a minimally invasive approach using peripheral cannulation and left ventricular fibrillation. Ten weeks after surgery, echocardiography was performed to assess mitral valve function. Animals were then killed, and gross mitral valve anatomy was examined ex vivo. RESULTS: : All animals survived 10 weeks without developing mitral regurgitation, structural leaflet damage, ring dehiscence, or endocarditis. In the minimally invasive compared with the midline sternotomy group (mean ± SD), significantly reduced recovery time (80 ± 16 vs. 327 ± 23 minutes, P < 0.01) and a tendency toward increased operating time (199 ± 33 vs. 168 ± 15 minutes, P > 0.05) and cardiopulmonary bypass time (98 ± 12 vs. 91 ± 11 minutes, P > 0.05) were observed. CONCLUSIONS: : By using a both minimally invasive and conventional midline sternotomy implantation techniques, the Medtentia double helix annuloplasty ring showed no mitral valve dysfunction or tissue damage 10 weeks postoperatively.

Accumulation of cholesterol precursors and plant sterols in human stenotic aortic valves.

The pathogenesis of aortic valve stenosis (AS) is characterized by the accumulation of LDL-derived cholesterol in the diseased valves. Since LDL particles also contain plant sterols, we investigated whether plant sterols accumulate in aortic valve lesions. Serum samples were collected from 82 patients with severe AS and from 12 control subjects. Aortic valves were obtained from a subpopulation of 21 AS patients undergoing valve surgery and from 10 controls. Serum and valvular total cholesterol and noncholesterol sterols were measured by gas-liquid chromatography. Noncholesterol sterols, including both cholesterol precursors and sterols reflecting cholesterol absorption, were detected in serum samples and aortic valves. The higher the ratios to cholesterol of the cholesterol precursors and absorption markers in serum, the higher their ratios in the stenotic aortic valves (r=0.74, P<0.001 for lathosterol and r=0.88, P<0.001 for campesterol). The valvular ratio to cholesterol of lathosterol correlated negatively with the aortic valve area (r= -0.47, P=0.045), suggesting attenuation of cholesterol synthesis with increasing severity of AS. The higher the absorption of cholesterol, the higher the plant sterol contents in stenotic aortic valves. These findings suggest that local accumulation of plant sterols and cholesterol precursors may participate in the pathobiology of aortic valve disease.

Complement system is activated in stenotic aortic valves.

OBJECTIVE: To examine the role of the complement system, a source of powerful proinflammatory mediators, in aortic valve stenosis (AS). METHODS AND RESULTS: Stenotic aortic valves (n=24) were obtained at valve replacement surgery, and non-stenotic (n=12) and early sclerotic (n=4) valves at cardiac transplantations. The terminal complement complex C5b-9 was stained by immunohistochemistry. Expression of the anaphylatoxin receptors C3aR and C5aR was studied in the valves by immunohistochemistry and RT-PCR, and in isolated valve myofibroblasts after stimulation with potential AS-accelerating factors (TNF-alpha and cigarette smoke) by RT-PCR. Cultured myofibroblasts were exposed to C3a, and their secretion of proinflammatory cytokines was assessed by ELISA. C5b-9 was found already in early aortic valve lesions, and its deposition was augmented in advanced stenotic valves. In stenotic valves, expression of C3aR mRNA was upregulated (p<0.05) and strong staining of C3aR and C5aR was detected. Myofibroblasts in stenotic, but not in control valves, expressed C3aR, and, in isolated myofibroblasts, TNF-alpha and cigarette smoke induced C3aR mRNA expression (p<0.05 for both). Stimulation of myofibroblasts with C3a resulted in enhanced secretion of MCP-1 (p<0.001), IL-6 (p=0.003), and IL-8 (p=0.03). CONCLUSIONS: In stenotic aortic valves, complement is activated leading to generation of the anaphylatoxins C3a and C5a. Upregulation of C3aR in the valves as a result of inflammation and external risk factors, such as cigarette smoke, leads to an inflammatory response in aortic valve myofibroblasts. Complement activation in stenotic valves emerges as a novel pathogenic component of AS and may serve as a therapeutic target in this disease.

How to build a cath-lab operating room.

Recent developments in cardiac surgery and interventional cardiology have led to the installation of integrated operating rooms that allow both surgical and endovascular procedures. These units offer surgical as well as angiographic equipment and personnel and therefore require special planning and design. A variety of integrated procedures can be performed. Hybrid coronary revascularization, percutaneous valve repair, and aortic stent-graft placement are current developments that are ideally performed in a cath-lab operating room. This review by an international working group of cardiac surgeons and cardiologists outlines the challenges involved with implementation of an integrated operating suite and suggests general planning and construction guidelines.

Increased expression of profibrotic neutral endopeptidase and bradykinin type 1 receptors in stenotic aortic valves.

AIMS: In aortic stenosis (AS), adverse remodelling of the valves may depend on altered local regulation of pro- and antifibrotic systems. We have recently shown that angiotensin-converting enzyme (ACE), which generates profibrotic angiotensin II and inactivates antifibrotic bradykinin (BK), is upregulated in stenotic aortic valves. Here, we analyse the expression of neutral endopeptidase (NEP), another profibrotic and BK-degrading enzyme, and of BK receptors in aortic valves in AS. METHODS AND RESULTS: Stenotic aortic valves (n = 86) were obtained at valve replacement surgery and control valves (n = 13) at cardiac transplantation. Expression levels of NEP and BK type 1 and 2 receptors (BK-1R and BK-2R) in aortic valves and in isolated valvular myofibroblasts were analysed by real-time PCR and immunohistochemistry, and NEP activity was quantified by autoradiography. NEP, BK-1R, and BK-2R mRNA levels were higher in stenotic than in non-stenotic valves (P < 0.05 for each) and the respective proteins localized to valvular endothelial cells and myofibroblasts. In stenotic valves, the proteolytic activity of NEP was significantly increased (4.5-fold, P < 0.001), and tumour necrosis factor-alpha induced the expression of NEP in cultured myofibroblasts. Finally, treatment of cultured myofibroblasts with an NEP inhibitor (phosphoramidon) downregulated the expression of profibrotic transforming growth factor-beta1, whereas addition of BK decreased the expression of collagens I and III which was reversed by a BK-2R antagonist. CONCLUSION: NEP activity is increased in stenotic aortic valves in parallel with increased expression of BK-receptors. The upregulation of NEP and BK-1R have the potential to promote valvular fibrosis and remodelling while the increase in BK-2R may represent a compensatory antifibrotic response. These findings add novel pathogenic insight and raise potential new therapeutic targets in AS.

Increased circulating concentrations and augmented myocardial extraction of osteoprotegerin in heart failure due to left ventricular pressure overload.

BACKGROUND: Osteoprotegerin (OPG) and the receptor activator of nuclear factor-kappaB ligand (RANKL), two cytokines regulating bone remodeling, have recently been raised as potential pathogenetic factors in cardiovascular diseases. We have studied circulating and myocardial OPG and RANKL in patients having severe aortic stenosis (AS) with or without heart failure (HF). METHODS: We studied 131 adults with AS. Blood was sampled from the aortic root, coronary sinus, and femoral vein at cardiac catheterization. LV myocardial biopsies were taken at surgery. Plasma OPG and soluble (s)RANKL were analyzed by ELISA, and myocardial OPG and RANKL by RT-PCR and immunohistochemistry. RESULTS: Circulating OPG was elevated in AS patients with HF, the association being independent of age, sex, and presence of coronary artery disease (beta=0.17, p=0.033). Elevated plasma OPG decreased after valve replacement in patients with preoperative HF (p=0.0005). Relative to its concentration in the aortic root, plasma OPG was reduced in the coronary sinus (p<0.05) and in the femoral vein (p<0.001), these arteriovenous gradients being accentuated in HF (p=0.003). CONCLUSIONS: HF due to LV pressure overload in AS increases circulating OPG and augments OPG extraction by the heart and peripheral tissues. OPG may be involved in the pathogenesis of HF and could serve as a useful biomarker in HF due to LV pressure overload.

Mediastinitis after more than 10,000 cardiac surgical procedures.

BACKGROUND: Poststernotomy mediastinitis as a complication is rare but disastrous. We assessed incidence, predisposing factors for, and outcome from, mediastinitis after cardiac surgery. METHODS: We studied 10,713 consecutive patients who underwent open-heart surgery from 1990 to 1999 in a tertiary care university hospital using data prospectively recorded in the hospital discharge register, operating room log, and the hospital's cardiothoracic surgery unit register. Those cases with possible mediastinitis were identified from the hospital infection register and discharge register. Patients' charts were reviewed and cases of mediastinitis confirmed based on criteria of the Centers for Disease Control and Prevention. RESULTS: The overall rate of mediastinitis was 1.1% (120 cases), and higher in coronary artery bypass surgery than in valvular surgery (1.2 vs 0.8%). No trend in incidence was detectable, although surgical patients became progressively older (mean age, 59 to 65 years, p < 0.01), and the proportion of women (from 25% to 31%; p < 0.01) and of patients with American Society of Anesthesiologists score over 3 (from 10% to 81%, p < 0.01) both increased. The rate of mediastinitis was almost twice as high in men (1.2% vs 0.7%, p < 0.01). In three body mass index (BMI) categories (<25, 25 to 30, and >30 kg/m2), rates of mediastinitis were 0.5%, 1.0%, and 1.8%. In multivariate analysis adjusted for age, sex, year, operation type, and perfusion time, the only predictor for mediastinitis was BMI. CONCLUSIONS: Mediastinitis is not diminishing. Larger populations at risk, for example proportions of overweight patients, reinforce the importance of surveillance and pose a challenge in focusing preventive measures.

Increased expression of elastolytic cathepsins S, K, and V and their inhibitor cystatin C in stenotic aortic valves.

OBJECTIVE: To investigate the possible role of elastolytic cathepsins S, K, and V and their endogenous inhibitor cystatin C in adverse extracellular matrix remodeling of stenotic aortic valves. METHODS AND RESULTS: Stenotic aortic valves were collected at valve replacement surgery and control valves at cardiac transplantations. The expression of cathepsins S, K, and V and cystatin C was studied by conventional and real-time polymerase chain reaction and by immunohistochemistry. Total cathepsin activity in the aortic valves was quantified by a fluorometric microassay. When compared with control valves, stenotic valves showed increased mRNA expression of cathepsins S, K, and V (P<0.05 for each) and a higher total cathepsin activity (P<0.001). In stenotic valves, cystatin C mRNA was increased (P<0.05), and cystatin C protein was found particularly in areas with infiltrates of inflammatory cells. Both cathepsin S and cystatin C were present in bony areas of the valves, whereas cathepsin V localized to endothelial cells in areas rich of neovascularization. Incubation of thin sections of aortic valves with cathepsins S, K, and V resulted in severe disruption of elastin fibers, and this cathepsin effect could be blocked by adding cystatin C to the incubation system. CONCLUSIONS: Stenotic aortic valves show increased expression and activity of elastolytic cathepsins S, K, and V. These cathepsins may accelerate the destruction of aortic valvular extracellular matrix, so promoting the progression of aortic stenosis.

Possible role for mast cell-derived cathepsin G in the adverse remodelling of stenotic aortic valves.

AIMS: Aortic stenosis (AS) is characterized by extensive remodelling of the valves, including infiltration of inflammatory cells, extracellular matrix degradation, and fibrosis. The molecular mechanisms behind this adverse remodelling have remained obscure. In this article, we study whether cathepsin G, an angiotensin II (Ang II)-forming elastolytic enzyme, contributes to progression of AS. METHODS AND RESULTS: Stenotic aortic valves (n = 86) and control valves (n = 17) were analysed for cathepsin G, transforming growth factor-beta1 (TGF-beta1), and collagens I and III with RT-PCR and immunohistochemistry. Valvular collagen/elastin ratio was quantified by histochemistry. In stenotic valves, cathepsin G was present in mast cells and showed increased expression (P < 0.001), which correlated positively (P < 0.001) with the expression levels of TGF-beta1 and collagens I and III. TGF-beta1 was also present in mast cell-rich areas and cathepsin G induced losartan-sensitive TGF-beta1 expression in cultured fibroblasts. Collagen/elastin ratio was increased in stenotic valves (P < 0.001) and correlated positively with smoking (P = 0.02). Nicotine in cigarette smoke activated mast cells and induced TGF-beta1 expression in cultured fibroblasts. Fragmented elastin was observed in stenotic valves containing activated cathepsin G-secreting mast cells and in normal valves treated with cathepsin G. CONCLUSION: In stenotic aortic valves, mast cell-derived cathepsin G may cause adverse valve remodelling and AS progression.

Induction of local angiotensin II-producing systems in stenotic aortic valves.

OBJECTIVES: The purpose of this study was to investigate the expression of angiotensin II (Ang II)-producing enzyme systems in normal and stenotic aortic valves. BACKGROUND: Chronic inflammation and fibrosis are involved in the pathogenesis of aortic stenosis (AS), but the detailed molecular mechanisms of this atherosclerosis-like process remain obscure. Angiotensin II, a powerful mediator of inflammation and fibrosis, may participate in AS progression. METHODS: Stenotic aortic valves (n = 86) were obtained from patients undergoing valve replacement surgery, and control valves (n = 11) were obtained from patients undergoing cardiac transplantation. Angiotensin-converting enzyme (ACE) and mast cell (MC)-derived chymase were quantified by reverse-transcription polymerase chain reaction, autoradiography, and immunostaining. The MCs, macrophages, and T lymphocytes were detected by immunohistochemistry, and angiotensin II type 1 receptor (AT-1R) by autoradiography. RESULTS: Compared with control valves, stenotic aortic valves showed a significant increase in both messenger ribonucleic acid (mRNA) (p = 0.001) and protein (p < 0.001) expression of ACE, which colocalized with macrophages. Similarly, the expression of AT-1R protein and chymase mRNA and protein was upregulated (p < 0.001), and the number of MCs was six-fold higher in stenotic than in normal valves. The MCs were associated with the calcified areas, and-in contrast to control valves-showed an increased degree of degranulation, a prerequisite for chymase secretion and action. CONCLUSIONS: Angiotensin-converting enzyme and chymase, two Ang II-forming enzymes, are locally expressed in aortic valves, and owing to infiltration of macrophages and MCs, are further upregulated in stenotic valves. These novel findings, implicating chronic inflammation and an increased expression of local Ang II-forming systems, suggest that therapeutic interventions aiming at inhibiting these processes may slow AS progression.