Despite severe LV dysfunction, increased 1-year mortality especially in the AS group, aortic valve replacement was associated with improved functional status, symptoms and EF in both groups and in most patients. We, therefore, conclude that aortic valve replacement in patients with severe LV dysfunction can be performed with acceptable risk.

Escalating medical costs, limitation of resources and the necessity to provide cost-effective medical care have created a need for systematic risk stratification and cost-benefit analyses in the background of an ongoing discussion. Results of heart surgery in octogenarians have been evaluated in a prospective single-center, study since 1990. 101 consecutive patients (55/ 101 = 54.5% female) aged 80 years and above (median: 81 years; interquartile range [IQR]: 80.0-82.5, total range [TR]: 80-92 years) undergoing open heart surgery at our institution between January 1990 and March 1996 were included into this prospective study. Prior to surgery, most patients were severely symptomatic being in functional NYHA classes either III (56.4%) or IV (31.7%). 61/101 (60.4%) patients underwent isolated coronary artery bypass grafting (CABG), 23 (22.8%) had aortic valve replacement (AVR), 14 patients (13.9%) had CABG combined with AVR or double valve replacement and 3 (3.0%) had mitral valve repair. Follow-up (median: 23.0 months. IQR: 10.5-39.0, TR: 1-72) was focused on long-term morbidity and quality of life. The impact of preoperative and operative risk factors on morbidity and mortality was determined by uni- and multivariate statistical analysis. The 30-days overall mortality in this study was 7.9%. The postoperative course was uneventful for 27 (26.7%) of our patients. Univariate risk factors of postoperative mortality were: left main stem disease (p < or = 0.044), ejection fraction < 45% (p < or = 0.006), preoperative intensive care unit (ICU) (p < or = 0.002), urgent or emergency operation (p < or = 0.034). The only independent predictor of operative mortality was preoperative ICU-stay (p < or = 0.008). Significant risk factors for the number of postoperative complications in the multivariate analysis were: prior stroke (p < or = 0.04), diabetes mellitus (p < or = 0.02), New York Heart Association (NYHA) class IV symptoms (p < or = 0.002) and prolonged cross-clamping time (p < or = 0.001). Mean postoperative length of stay in the ICU was 3.9 +/- 3.9 days. Late morbidity was not related to postoperative complications. Cumulative survival was 87.9%, 79.5% and 72.9% at one, two or five years, respectively. After hospital discharge, 67/93 patients (82.8%) were in NYHA functional class I or II. Cardiac surgery in very elderly patients can be performed with acceptable operative risk and a favorable long-term outcome. The individual patient risk-profile including significant co-morbid conditions and severity of the heart disease predicts not only survival but the extent of perioperative morbidity.

Tissue engineering is a promising approach to obtaining lifetime durability of heart valves. The goal of this study was to develop a heart valve-like tissue and to compare the ultrastructure with normal valves. Myofibroblasts and endothelial cells were seeded on a type I collagen scaffold. The histologic organization and extracellular matrix were compared in light and electron micrographs. Radiolabeled proteoglycans were characterized by enzymatic degradation experiments. In tissue engineered specimens, cross sectional evaluation revealed that the scaffold (300 microm) was consistently infiltrated with myofibroblasts. Both sides were covered with a multicellular layer of myofibroblasts and overlaid by endothelial cells (50 microm). A newly formed extracellular matrix containing collagen fibrils and proteoglycans was found in the interstitial space. Collagen fibrils with a 60 nm banding pattern were found in both specimens. Small sized proteoglycans (65 nm) were associated and aligned at intervals of 60 nm with collagen fibrils. Large sized proteoglycans (180 nm) were located outside the collagen bundles in amorphous compartments of the extracellular matrix. The majority of glycosaminoglycans were chondroitin/dermatan sulfate, and a minority were heparan sulfate. The morphology and topography of cells and the organization of extracellular matrix in artificial tissues strongly resembles those of native valve tissues.

Proteoglycans such as versican, decorin, and perlecan are important components of the extracellular matrix in various tissues. They play an important role in water homeostasis, tissue elasticity, prevention of calcification, and thrombogenicity. The aim of our study was to detect such proteoglycans in engineered tissue and compare them with the proteoglycans of native porcine heart valves. Myofibroblasts were seeded on a type I collagen scaffold. Thereafter, endothelial cells were seeded onto the presettled myofibroblasts. The newly formed tissue was histologically and immunohistochemically examined. Cupromeronic blue was used for ultracytochemical staining of proteoglycans. Radiolabeled proteoglycans were isolated by ion-exchange chromatography and characterized by enzymatic degradation. Three differently sized proteoglycan precipitates were found. The large-sized proteoglycan (154 nm) was located outside the collagen bundles in a rarely structured extracellular matrix compound. The small-sized proteoglycan (46 nm) was aligned along the collagen bundles at intervals of 60 nm. The intermediate-sized proteoglycan (56 nm) was detected on the cell surface of myofibroblasts. The glycosaminoglycans included 80% chondroitin and dermatan sulfate and 20% heparan sulfate. We conclude that proteoglycans play an important role in the functional integrity of cardiovascular tissues. This study shows the successful production of a heart valve-like tissue with proteoglycans resembling, in terms of type, production, and distribution, proteoglycans of native heart valves.

Intrinsic calcification of glutaraldehyde-fixed porcine valves was induced in vitro. Electron microprobe analysis and x-ray powder diffraction findings were in keeping with apatite crystallization, such as that occurring in valve xenografts implanted in vivo. The model may be of value to accelerate the screening of anticalcific agents and may reduce the need for animal experiments.