Cadaver Vein Allografts May Still Have a Role in Lower Limbs

BY PATRICE WENDLING

CHICAGO -- Cadaver vein allografts are an option for reoperative lower-extremity revascularization in patients threatened with amputation who have no suitable autogenous vein, Dr. Mohsen Bannazadeh and colleagues said at the annual meeting of the Midwestern Vascular Surgical Society.

"Patency rates are poor, but limb salvage rates are acceptable," he said. "Patients older than 70 [years] are more likely to have inferior results."

PREVIOUS PROCEDURES OR POOR VEIN CALIBER CAN MAKE A CADAVER SAPHENOUS VEIN ALLOGRAFT THE LAST RESORT FOR A SUBSET OF PATIENTS.

Those conclusions are based on a review of 56 patients with 66 cadaver saphenous vein allografts at the Cleveland Clinic Foundation between January 2000 and January 2007.

The mean patient age was 71.6 years. Indications for surgery were tissue loss in 73% and ischemic rest pain in 27%. Cadaver saphenous vein allograft was the first revascularization procedure in just 28% of patients and the secondary procedure in 72%.

Comorbidities included hypertension (83%), tobacco use (73%), coronary artery disease (70%), elevated cholesterol level (57%), and diabetes mellitus (53%).

Overall patency rates tended to fall after the first 6 months, said Dr. Bannazadeh, a vascular surgeon with the clinic. Primary patency rates were 89% at 30 days, 42% at 6 months, and 19% at 12 months. Secondary patency rates were 92%, 64%, and 42%; limb-salvage rates were higher at all three time points (95%, 82%, and 73%, respectively).

At 1 year, patients having first-time procedures, compared with those with reoperative procedures, had primary patency (17% vs 19%), secondary patency (43% vs. 40%), and limb-salvage rates (71% vs. 74%) that were not significantly different. However, survival at 1 year was significantly higher in reoperative procedure patients compared with first-time patients (90% vs. 52%), he said.

Procedure-related complications included graft infection in three patients, graft thrombosis in three, pseudoaneurysm in three, and bleeding in two. The perioperative mortality rate at fewer than 30 days was 4%.

Multivariate analysis showed there were no predictors of primary patency, primary-assisted patency, or limb salvage. However, age greater than 70 years (hazard ratio 2.39) and cadaver saphenous vein allograft as a secondary procedure (HR 3.3) were risk factors for secondary patency loss. Older patients (HR 2.92) and those with renal insufficiency (HR 2.92) were at greater risk of death.

During the question session, one audience member said he was troubled by the concept of unavailable autogenous veins, suggesting that surgeons "get lazy once the saphenous vein is gone" and could use upper-extremity veins that provide better patency and durability than cadaveric veins.

Dr. Bannazadeh said that any autogenous vein is preferable to cadaveric veins. Earlier, he had noted that about 10%-20% of patients requiring lower-limb revascularization do not have a suitable saphenous vein because of previous revascularization, previous cardiac bypass graft, or poor vein caliber, which make cadaver saphenous vein allograft the last resort for a limb-salvage procedure in these patients.

When asked to comment on this article, Dr. E. John Harris stated: "In patients without suitable autogenous vein conduit, cadaver vein allografts experience inferior patency rates compared to currently available PTFE grafts (for example, Distaflo) and PTFE grafts with vein patches or cuffs at the distal anastamosis, at a considerably higher cost than the PTFE grafts.

"I am uncertain of the benefit of these cadaveric grafts, as they also are susceptible to graft infection as are the traditional prosthetic grafts. With a primary patency of less than 20% at 1 year, and 42% secondary patency at 1year, I am surpised by the limb salvage rate of 73% at 1 year, which may reflect benefit from previous interventions, such as profundaplasty or femoral endarterectomy, as the bypass was a secondary procedure in 72% of patients."

Dr. Harris is a professor of surgery in the division of vascular surgery, Stanford University School of Medicine.