A new semi-automatic endothelial cell seeding technique for biological prosthetic heart valves.

BACKGROUND: Until today, tissue heart valve prostheses have been made with biological dead porcine or bovine tissue. However, the durability of this tissue is limited due to degeneration and calcification. Surface seeding with vital human endothelial cells (EC) could improve valve durability and bio-compatibility. A new seeding technique that includes a newly developed special seeding device is presented here. METHODS: The aortic valve, including a cylinder of the aortic root, was prepared from a fresh porcine heart taken from the slaughterhouse. Porcine endothelial cells were removed by surface treatment with chemical detergent solutions. A new seeding device with an integrated CO2-incubator was designed. The device is composed of: the seeding chamber (SC), the rotation unit (RU), and the Control Unit (CU). The porcine aortic root cylinder with the valve leaflets is placed into the SC. A matrix of fibronectin is applied to the acellular valve. The SC is then filled with the endothelial cells suspended in modified Dulbecco's eagle medium (DMEM). Under cell culture conditions, the endothelial cell seeding of the tissue valve is established by rotating the valve around two orthogonal axes simultaneously and independently. This is done following the software controlled preset parameters. RESULTS: Using initial endothelial cell seeding concentrations of 6x10(6) endothelial cells/ml DMEM, it was possible to achieve a seeding efficiency of 80-85% within 3-4 hrs. Cell viability tests proved that 90-95% of the seeded endothelial cells are vital after the seeding procedure. CONCLUSIONS: This new seeding technique allows the complex warped surface of a tissue heart valve to be covered with vital endothelial cells to form a confluent endothelial cell monolayer.

Diagnosis and management of left ventricular assist device valve-endocarditis: LVAD valve replacement.

A 57-year-old man who has been wearing a Novacor N100 left ventricular assist device (LVAD) for more than 3 years suffered from LVAD endocarditis. Only by immunoscintigraphic methods was it possible to localize the septic focus. After successful exchange of in- and outflow tract valves, the infection was eradicated. Microscopic investigation confirmed the scintigraphic findings: Gram-positive bacteria were found. The valves showed no gross degenerative lesions after more than 1,100 days of implantation. The patient is now doing well.

Clinical experience with autologous endothelial cell-seeded polytetrafluoroethylene coronary artery bypass grafts.

OBJECTIVE: Autologous endothelial cell seeding was used to improve the patency of 4-mm polytetrafluoroethylene vascular prostheses. METHODS: Since 1995, 14 patients with coronary artery disease received 21 autologous endothelial cell-seeded polytetrafluoroethylene vascular bypass grafts for coronary artery revascularization. The polytetrafluoroethylene grafts were seeded with the endothelial cells in a multiple step procedure, including cell culture techniques before coronary bypass operation. With the use of extracorporal circulation and cardioplegic arrest, a bypass operation was performed by means of conventional surgical techniques. RESULTS: After a mean postoperative follow-up of 27.7 months (range, 7.5-48 months), the graft patency rate is 90.5%. Follow-up angiograms of the aorta-coronary polytetrafluoroethylene bypass grafts showed patent bypasses in all cases except two. Angiograms of all 19 patent endothelial cell-seeded polytetrafluoroethylene bypass grafts showed a smooth luminal borderline without stenotic regions. The percutaneous transluminal angioscopic evaluation showed a glossy white and smooth endoluminal graft surface without any fibrin, platelet, or erythrocyte deposits. Intravascular ultrasonographic examinations confirmed the results. CONCLUSION: Patency of autologous endothelial cell-seeded 4-mm polytetrafluoroethylene vascular prostheses as coronary artery bypass grafts was much better than that of unseeded polytetrafluoroethylene grafts. Further evaluations and a larger population of patients will prove whether the encouraging patency will last.

[Acute and chronic mechanical circulatory support]. / Akute und chronische mechanische Kreislaufassistenz.

Mechanical circulatory support and mechanical unloading of the left ventricle become more and more routine in clinical treatment regimens of both acute and chronic heart failure. Along with increasing availability of different cardiac assist systems one can adjust the degree of support according to the clinical situation. We report about our experience in the period between January 1994 and May 1995 with following assist systems: Hemopump, centrifugal pumps, Medos, HIAVAD and Novacor. We implanted those devices in 21 patients out of following indications: postinfarct--cardiac failure (CF), postcardiotomy CF, elective postcardiotomy support, myocarditis CF and "bridge" to transplant. Ten patients survived the period of mechanical support and could be weaned successfully. Circulatory support was sufficient in all cases, indication, time of implantation, anticoagulation and prevention of infections are discussed.

[Glomus tumors: a diagnostic and surgical challenge?]. / Glomustumoren: eine diagnostische und chirurgische Herausforderung?

Within a population of 1150 vascular patients over a time period of 10 years we saw a carotid body tumor (synonymous chemodectoma) in only 11 cases. A correct preoperative diagnosis was found only in three patients. Before being treated by a specially trained team of vascular surgeons, eight patients had undergone inadequate operations. These were performed with a high incident of local complications. Simple bedside physical examination of the patient while looking for the signs of Fontaine and Kocher I + II (20) assures the diagnosis. Confirmation can be achieved by color-flow Doppler sonography (2). For the surgical resection, the only therapeutic alternative to the "gold standard" is angiography in digital subtraction technique which illustrates the blood supply of the tumor (70% exclusively by the external carotid artery). Also, it shows the typical intercarotid widening and the rich vascular conglomerate in between. Malignancy was detected in one case only (pulmonary metastasis). In two cases concomitant tumors of the jugular vein were seen. The interruption of the blood flow in the external carotid artery facilitates the surgical approach substantially. The ligature of this vessel (six patients) and the interposition of saphenous vein grafts (all 11 cases) for reconstruction of the internal carotid vessel were employed as the surgical strategy. Even the exstirpation of a large tumor (18 x 11 x 9 cm) extending from the skull base and almost reaching the left clavicular bone was successfully performed.(ABSTRACT TRUNCATED AT 250 WORDS)