To date no prosthetic vascular prosthesis performs as well as the autologous saphenous vein in diameters of 6 mm and less. The purpose of this study was to compare the in vitro and in vivo performance of a new glutaraldehyde stabilized, narrow diameter (4 mm), vascular prosthesis fashioned from bovine ureters (Flonova) with the saphenous vein and polytetrafluoroethylene (PTFE) prostheses. The methods used for the comparative in vitro analysis of the bovine ureter and saphenous vein were modifications of tests recommended by the American National Standards for Vascular Prostheses. Blood compatibility was evaluated by measuring platelet consumption in an artificial circulation, and heparin uptake was quantified using tritiated heparin. The results indicate that the bovine ureter grafts have an adequate degree of mural integrity and hemocompatible properties comparable to saphenous vein. The in vivo patency in a canine bilateral femoral interposition model was 62.5% (10/16) for the bovine ureters and 43.75% (7/16) for PTFE. Bovine ureter grafts appear to have an excellent potential for use in narrow diameter peripheral and coronary arterial bypass procedures and warrant further investigation.

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PubMedDate not supplied

Evaluation of closed pericardial patch grafting for management of severe pulmonic stenosis.

Closed pericardial patch-grafting has been advocated for the treatment of severe pulmonic stenosis. In this study pre- and postoperative echocardiography was used to determine if the transvalvular pressure gradient was successfully lowered by this surgery and whether it remained lowered long term. The valvulotomy-ventriculectomy wire was passed using a blunt needle in four dogs (Bresnock technique1) and via a soft catheter in five dogs (Shores and Weirich modification). Eight of nine patients survived the perioperative period. These dogs were assessed up to 40 months following surgery for clinical and echocardiographic changes. Five cases showed significant decrease in peak pulmonic pressure gradient immediately after surgery (decreasing by 50-81%, P < 0.05), and six cases showed significant decrease 2 to 40 months postoperatively (decreasing by 31-80%, P < 0.005) when compared to preoperative values. There was no significant change in pulmonic pressure gradient from immediately postoperatively to 2 to 40 months postoperatively (P < 0.48). Six dogs showed clinical improvement postoperatively, however persistent right ventricular hypertrophy was observed in all cases. One dog died with symptoms of congestive heart failure 16 months postoperatively. Closed pericardial patch grafting can improve clinical signs in symptomatic patients, however the surgery has significant risks, long term prognosis for these patients is guarded and recurrence of clinical signs and development of congestive heart failure is possible. Cardiac changes can be monitored with Doppler flow echocardiography. Patients with extremely elevated preoperative pressure gradients may be expected to have poorer outcomes.

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PubMedDate not supplied

Clinical significance of monoclonal immunoglobulinemia.

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Adult↗