Roland Fasol

Endothelial cell seeding of polytetrafluoroethylene vascular grafts in humans: A preliminary report

The importance of initial human trials with autologous endothelial seeding lies not only in the implementation of a promising idea but also in the fact that canine data are only partially applicable to humans. The surface area of jugular veins in humans is much smaller than in dogs and considerably longer grafts are needed. Moreover, the reproductive capacity of adult human endothelial cells under in vivo conditions, which probably determines the success of seeding more than the seeding density, is also uncertain. Therefore the efficiency of autologous endothelial seeding in humans was investigated in 18 patients undergoing distal femoropopliteal bypass surgery. The average surface area of the jugular veins was 4.9 +/- 1.7 cm2 with an average cell yield of 32.6 +/- 18.0 x 10(4). The mean number of seeded cells per square centimeter of graft surface was 3.1 x 10(3). In a follow-up extending for 14 weeks, plasma levels of platelet factor 4 and beta-thromboglobulin as well as the platelet function in the whole blood aggregometer showed significantly better results in the seeded group. Plasma thromboxane B2, uptake and survival of indium 111-labeled platelets, and Doppler ultrasound investigations also favored the seeded group, but the results were statistically insignificant. No difference at all was found for the platelet dense granule compounds, releasable adenosine triphosphate and platelet serotonin. Thus our findings did not indicate the development of a closed endothelialized surface after 14 weeks, which is a period three times as long as the one required for confluent endothelial cell coverage in dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Triangular resection of the anterior leaflet for repair of the mitral valve

Isolated anterior mitral leaflet prolapse, unlike posterior prolapse, is a difficult lesion to repair and may become a demanding surgical procedure. We report our experience with a technique of a triangular resection of the anterior leaflet to repair isolated segmental anterior leaflet prolapse in 18 patients. This technique simplifies the repair procedure and is a safe and rapid procedure which allows excellent results.

Repair of mitral valve billowing and prolapse (Barlow): the surgical technique

Mitral valve repair in patients with mitral valve billowing and prolapse (Barlow) can be a demanding surgical procedure. A mitral valve repair method, which incorporates the complete resection of the middle scallop of the posterior leaflet, a sliding and folding plasty with the remaining lateral scallops combined with a triangular resection of the anterior leaflet and a ring-annuloplasty was developed, which maximizes predictable anatomic and physiologic efficacy of this repair and minimizes unpredictable results. A total of 37 consecutive patients underwent mitral repair with this method from 1996 to 1998, with consistently excellent results. Short-term follow-up information collected after 22.7 +/- 8.6 months showed one late death and 93.0% of all surviving patients in New York Heart Association functional class I or II. There were no late reoperations and no thromboembolic, bleeding, or other complications. No patient had recurrent mitral regurgitation.

Papillary muscle repair surgery in ischemic mitral valve patients

BACKGROUND Ischemic mitral regurgitation (MR), when ischemia/infarction has resulted in fibrotic degeneration and elongation of papillary muscles, carries a high risk for the patient and a technical challenge for the surgeon. We have developed a papillary-shortening plasty for this specific pathology. METHODS Papillary muscle repair was performed in 88 patients (7.2%) where degenerated and fibrotic elongated papillary muscles were found, which resulted in a prolapse of one or more parts of the mitral valve leaflets (MR III-IV). All patients had a papillary muscle-shortening plasty using a pericardium pledged-reinforced polytetrafluoroethylene suture and a ring annuloplasty. Because the cause of regurgitation in this specific group of patients was ischemic, concomitant coronary bypass grafting was required in all patients, with 2.2 grafts/patient. RESULTS There were five hospital deaths (5.7%). Postoperative mitral valve function was satisfactory in all patients: no residual mitral regurgitation (MR 0) was found in 80 patients (90.9%), mild regurgitation (MR I) in 5 patients (5.7%), and moderate regurgitation (MR I-II) was observed in 3 patients (3.4%). Within a short mean follow-up period of 18.6 months (3 to 40 months), there was one late death (1.2%). The actuarial freedom from reoperation and thromboembolic complications was 100%, but there were two anticoagulation-induced gastric bleeding complications (2.3%). All patients were in New York Heart Association functional class I or II at the time of follow-up. CONCLUSIONS Our data show that careful assessment of papillary muscle pathology is mandatory, and that a papillary muscle-shortening plasty is a simple but valuable surgical tool to repair the mitral valve in this specific group of high-risk patients with ischemic mitral regurgitation.

Early failure of bioprosthesis by preserved mitral leaflets

Complete preservation of the posterior mitral valve leaflet caused early thrombotic occlusion of two cusps of a Carpentier-Edward pericardial prosthesis implanted into the mitral position with subsequent bioprosthetic failure, necessitating reoperation.

Left ventricular rupture after mitral surgery: Repair by patch and sealing

Ventricular wall rupture after mitral valve replacement is an infrequent but dreaded complication. We have experienced this problem in two separate instances of type III left ventricular rupture and report the successful repair by a novel technique with the use of a new sealant, the AdvaSeal (FocalSeal), in a sandwitch repair procedure.

Enzyme activities of purine catabolism and salvage in human muscle tissue.

Metabolic differentiation in muscle is closely related to the elementary systems of energy supplying metabolism. Most strikingly this is reflected at the level of enzymatic organization (1). White (fast) muscle is characterized by high capacities of glyco-genolysis, glycolysis and lactate fermentation, whereas the capacities of glucose phosphorylation, citric acid cycle, oxidative phosphorylation and fatty acid oxidation are low. Red (slow) muscles, heart and smooth muscles show inverse characteristics. Alterations of enzyme activities during red and white muscle differentiation in vitro suggest the existence of one myogenic cell with the potential to exhibit those properties which are characteristic for any type of muscle (2). According to this concept the dichotomy between white and red muscles becomes apparent after innervation. Furthermore it was demonstrated that white (fast contracting) muscles can be transformed into red (slow contracting) muscles by longterm electric stimulation with low frequencences (3, 4). The adaptation to the nerval stimulus was reflected by structural changes and by alterations in the activites of enzymes (4).

Allogenic, Multidonor In Vitro Endothelialization of Small Diameter PTFE Grafts in Baboons

The early effect of allogenic in vitro endothelialization was assessed in small- diameter vascular prostheses. Cryopreserved and pooled venous endothelial cells (ECs) from 13 baboons of similar blood group were used for confluent in vitro endothelialization of fibrin glue-coated polytetrafluoroethylene vascular grafts. Bilateral femoral interpositions (12 cm) of experimental and control grafts were subsequently implanted into a separate group of 18 male baboons with the same blood group as that of the pooled cells. After sixteen days of implantation the patency rate of grafts of the endothelialized group was similar to that of the control group (55.6% vs 61.1%, p>0.1). Scanning electron microscopy revealed that 44.4% of experimental grafts were completly free of endothelium, while the remaining grafts showed a moderate mean EC coverage of 34.4 17.1%. These remaining ECs were found mainly as small islands densely covered by leukocytes. The majority of these white cells resembled granulocytes, although adherent lymphocytes were also regularly observed. Since surface morphology does not explain the mechanism of EC loss, further experiments must elucidate this question. If rejection is found to be the primary cause for this cell loss, the use of major histocompatibility complex (MHC) matched EC subpools might be considered.

Aortic Aneurysm Repair in Patients with Coronary Heart Disease: Strategy for Diagnosis and Treatment

Coronary heart disease, specifically myocardial infarction, represents the major risk factor for patients undergoing surgical repair of their abdominal aortic aneurysm. About 75% of all patients in the series of 285 cases were without any signs or symptoms of coronary heart disease. Nevertheless, 21.8% of these patients required additional cardiologic screening in order to assess a possible suspected coronary heart disease, which made urgent coronary angiography necessary in 4.6% of all the patients. Furthermore, 7.3% of all the patients required percutaneous transluminal coronary angioplasty (9=3.15%) or coronary artery bypass grafting (12=4.2%) prior to their scheduled aneurysm operation. Owing to this concept of careful preoperative assessment of adjacent coronary risk factors in patients with aortic aneurysms, the overall morbidity and mortality has dropped from 7.6% to 3.1% over the last ten years.

ENZYME ACTIVITIES OF PURINE CATABOLISM AND SALVAGE IN HUMAN MUSCLE: 184

Since there is little information about the enzyme distribution of purine catabolism and salvage available, it was reasonable to determine activities of some key enzymes in human tissue samples. This might be of importance for purine metabolism of human muscle of different origin. Using radiochemical tests the following enzyme activities were detected: adenosine kinase (AK), adenine phopshoribosyl-transferase (APRT), hypoxanthin guanine phosphoribosyltransferase (HGPRT), adenosine deaminase (ADA), and purinenucleoside phosphorylase (PNP).The following activities were determined: