LAKE BUENA VISTA, FLA. – Primary, primary-assisted, and secondary patency and limb salvage rates are similar in transplant and nontransplant populations, but renal transplant patients have slightly – though not significantly – worse outcomes than do heart transplant patients, according to findings from a study of endovascular peripheral interventions in these populations.
A total of 122 lesions in 58 renal or cardiac transplant patients were identified using information from a prospective lower-extremity database encompassing more than 1,500 interventions performed from 2004 through 2010 at a single, high-volume vascular and transplant center. The data were cross-referenced with heart failure and renal transplant registries from the same center, Dr. Katherine A. Gallagher said at the annual meeting of the Society for Clinical Vascular Surgery.
The transplant patients – 44 men and 14 women with a mean age of 63.5 years – all were on active immunosuppressive treatment and were followed clinically and with noninvasive laboratory testing for 30 months. Indications for lower-extremity interventions were claudication in 48% of cases and critical limb ischemia in 52% of cases. Mean lesion length was 108.6 mm, said Dr. Gallagher of Weill Cornell/Columbia University, New York.
Primary, primary-assisted, and secondary patency and limb salvage rates were "essentially the same" at 50 months in the transplant patients and in 1,162 nontransplant control patents, at about 40% vs. 45%, 55% vs. 60%, 60% vs. 65%, and 70% vs. 65% cumulative survival, respectively, she said.
Subgroup analyses showed that heart transplant patients showed a trend for better primary patency rates than did renal transplant patients with similar TASC classification and comorbid conditions (about 75% vs. 55%) , although the heart recipients had less critical limb ischemia.
After controlling for potential confounding factors, the researchers found in subgroup analyses that male transplant patients had significantly less severe disease and much better outcomes, Dr. Gallagher said in an interview.
Mean follow-up in these patients was 18.6 months, Dr. Gallagher noted.
Percutaneous intervention has become the first-line treatment for many patient groups, but outcomes in transplant patients prior to this study were relatively unknown, she said.
"We do know that the incidence of peripheral artery disease [PAD] is high in patients with renal insufficiency, and we know that both open and endovascular outcomes in this patient cohort portend poor patency and limb salvage rates," she said, adding that there is evidence that renal transplant patients have a high incidence of PAD, but outcomes following endovascular intervention in these populations are unknown.
"We can theorize that they might have improved outcomes because they have improved renal function, but they might also have poorer outcomes because of the deleterious effects of immunosuppression as it relates to hyperlipidemia and hyperglycemia," she said.
Furthermore, it is known that cardiac transplant patients are at risk for PAD, but the effects of immunosuppression in this population are unknown.
"Specifically these patients are on a lot of tacrolimus and sirolimus, which have been well studied in drug-eluting stents, but we don’t know the effects of these drugs on endovascular interventions," she said.
In this study, transplant patients had higher rates of diabetes and renal insufficiency – two factors shown to be independent predictors of poor outcome – so they would be expected to have poorer outcomes than would nontransplant patients, yet outcomes between the two groups were very similar.
"We believe this is potentially due to protective effects from systemic immunosuppression, although this requires further investigation, she concluded.
Dr. Gallagher said that she had no relevant financial disclosures.