Quick Response to Vascular Access Failure Aids Patency

Mitchel L. Zoler

PONTE VEDRA BEACH, FLA. -- Early diagnosis and treatment of vascular-access failure in patients on chronic dialysis result in better long-term patency, based on a review of 294 patients, said John A. Bittl, M.D., at the annual meeting of the Society for Cardiovascular Angiography and Interventions.

The average patency rate of a dialysis bridge graft is 41%-75%; an arteriovenous fistula that's used for access has a slightly better patency rate, said Dr. Bittl, a cardiologist at the Ocala (Fla.) Heart Institute.

The series reviewed by Dr. Bittl included 294 patients who were treated for vascular access failure at the institute during January 2003-December 2004. The series included 128 patients with fistula access and 166 patients with grafts. At the time they were initially examined, 49% of the patients had thrombosed in their vascular access.

Immediate patency was produced in 95% of these patients. Follow-up was 100%, and the overall, median duration of maintained patency following treatment was 206 days. Patency was maintained the longest in patients with fistula access that had not thrombosed, with a median duration of 371 days. Grafts that had not thrombosed remained patent for a median of 200 days. But in patients who had thrombosed, the median patency duration for both fistulas and grafts was 140 days, Dr. Bittl said.

Dr. Bittl and his associates provide round-the-clock response to patients who have vascular access failure. The procedure, which is done for all patients on an outpatient basis, involves a cross-stent approach, placing one sheath in the inflow direction and a second in the outflow direction.

Contrast is not used because injecting fluid through the stenosis at this stage risks triggering embolization. Instead, the procedure is visualized with fluoroscopy.

The first step is to pass an AngioJet device through the inflow and outflow tracts to remove most of the thrombus. The AngioJet is available with a specially designed catheter for dialysis tracts. The next step is to dilate the outflow stenosis with an angioplasty balloon, usually a 7- or 8-mm size. Many patients have a compressed, white thrombus that is resistant to removal with the AngioJet. To extract this, Dr. Bittl uses a Fogarty, balloon-tipped catheter to mechanically remove the remaining clot. Finally, central venography is done to document the patent vessels. In some patients, a stent may be needed.

The procedure is done on patients who have been treated with aspirin and heparin, although bivalirudin (Angiomax) can be substituted for heparin. All patients also receive antibiotic prophylaxis.