HUNTINGTON BEACH, CALIF. – Cryopreserved arterial homografts show promise for reperfusion in patients with severe vascular disease whose only other option may be a below- or above-the-knee amputation, results of a retrospective case series suggested.
Dr. Joseph Naoum and his colleagues in the division of vascular surgery at Methodist Hospital in Houston successfully used cryopreserved arterial homografts–arteries harvested from cadavers and frozen–to reperfuse feet in 13 such patients.
Dr. Joseph Naoum
After 18 months, the cumulative patency rate was 58.6%, Dr. Naoum said at the annual Academic Surgical Congress.
"If we had not used arterial homografts, [these patients] would have certainly required below-the-knee or above-the-knee amputations," Dr. Naoum said in an interview.
The findings add weight to the small body of literature showing that homografts can help in such cases.
The patients’ average age was 71 years, and five were men. Comorbidities included peripheral vascular disease (12 patients), diabetes (7), foot infections or gangrene (10), foot ischemia but no wound (2), and an infected Gore-Tex graft (1).
Dr. Naoum said he chose arterial homografts instead of vein homografts to cut down potential graft complications; arteries have more uniform diameters and no valves.
Four patients got femoral below-the-knee popliteal grafts; four had femoral- to anterior-tibial-artery grafts; and three had femoral- to posterior-tibial-artery grafts. Two patients received femoral- to peroneal-artery grafts.
Only patients who could tolerate the surgery, which is a longer and more complicated procedure than leg amputation, and who were currently ambulatory underwent the procedure.
"There is no point using these homografts to preserve limbs if patients are not walking," Dr Naoum noted.
The grafts cost about $3,000 and range in length from about 25 to 35 cm, depending on the donor.
"We like to ask for the longest piece possible," to avoid splicing. "However, we get what is available based on the diameter requested and blood-type match," Dr. Naoum said.
Once thawed per supplier directions, the homografts handle like any other graft tissue. Suturing is standard.
Dr. Naoum said he and some of his colleagues like to tunnel the grafts under subcutaneous fat instead of anatomically, to minimize compression. They also prefer to arterialize the graft before making the distal anastomoses to elongate the graft for better sizing and to work out any kinks, he said.
Patients were told to stop smoking after their operations (five of them smoked), and they were put on aspirin, Plavix (clopidogrel), and a statin, if they were not on one already. There’s no evidence that antirejection drugs are needed, Dr. Naoum said.
Two patients later needed toe amputations, and four required transmetatarsal amputations.
The 18-month patency rate was less than the perhaps 75% patency rate that would be expected had they been grafted with their own veins. Even so, the restored blood flow "was enough to allow the wounds to heal," Dr. Naoum said.
He said he plans to continue studying the use of arterial homografts to better define factors associated with good outcomes.
"What is needed is a greater experience to identify patients who will benefit most from such procedures, and those in whom an amputation may obviate a bypass that will not last," he said.
Dr. Naoum is also curious about why the grafts fail; two patients needed angioplasty to keep their grafts open, and thrombectomy was performed in one.
Cryopreservation makes cells thicker, perhaps causing intimal tears and scarring. Poor runoff is also a problem. If distal vessels can’t handle the new blood flow, pressure builds up in the graft, leading to clots and other problems, he said.
Dr. Naoum said that he was a consultant for CryoLife Inc., a major supplier of arterial homografts, in 2009, but is no longer involved with the company. He said he received no discounts on the grafts used in the case series.