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Patency important to patients with CLI, but issue complex
HOLLYWOOD, Fla. — Patency of the tibial arteries appears to confer positive outcomes for patients with critical limb ischemia, but many factors determine ultimate outcomes such as amputation and mortality, according to a presenter at the International Symposium on Endovascular Therapy.
Endovascular strategies to increase patency after below-the-knee interventions have not yet borne encouraging data, said Thomas Zeller, MD, PhD, head physician in the department of angiology at Universitäts Herzzentrum, Bad Krozingen, Germany.
Some data have shown that while primary patency correlates with continued clinical improvement, it correlates poorly with limb salvage, but secondary patency correlates well with limb salvage, Zeller said.
“If we treat a patient only once with plain balloon angioplasty, we will face a reocclusion rate of more than 50% at 1 year, so this results in surveillance programs that result in a redo procedure as soon as reocclusion is detected,” he said. “A secondary or tertiary patent vessel is closer to the limb salvage rate. So primary patency is not the right tactical measure to correlate with limb salvage.”
The problem, Zeller said, is that each additional procedure results in a loss of a vessel segment.
However, the DEBATE-BTK study showed that additional interventions for reocclusions also improved the wound-healing rate, and a study from Japan showed a relationship between ulcer healing and ambulatory status, he said.
“Ulcer healing was much better if the vessel was patent after the index procedure, compared with lesions that developed restenosis,” Zeller said.
Drug-eluting stents for below-the-knee lesions have been shown to improve primary patency compared with balloon angioplasty or bare-metal stents, but other outcomes have been inconsistent, he said.
However, according to Zeller, a meta-analysis showed the primary patency advantage for DES treatment may also relate to improvements in Rutherford class, wound healing, target lesion revascularization and event-free survival.
Unfortunately, most trials have been conducted in patients with lesions < 10 cm, and most patients with CLI have lesions > 10 cm, he said. “We know that the performance of [DES] in such lesions is not evaluated yet,” Zeller said. “[BMS] which are dedicated devices for long lesions do not perform very well. Self-expanding nitinol stents, which may be the best stents available for the treatment of long lesions, are not sufficiently preventing restenosis or reocclusion. We have no dedicated [DES] with sufficient length for below-the-knee treatment.”
This implies drug-eluting balloons may be the best solution, but so far they have not bested plain balloon angioplasty in lesions below the knee, he said, noting that current research is evaluating whether a DEB combined with atherectomy will improve outcomes.
“Even if amputation is influenced by multiple factors, patency of tibial arteries matters,” Zeller said. “Secondary patency is associated with limb salvage rates. However, reinterventions are associated with increased risk and costs and might harm vessel integrity in the longer term. Therefore, intervention strategies increasing the primary patency rate following [below-the-knee] interventions are eagerly awaited.” – by Erik Swain
Reference:
Zeller T. Townhall: Managing the epidemic of critical limb ischemia. Presented at: International Symposium on Endovascular Therapy; Feb. 4-8, 2017; Hollywood, Fla.
Disclosure: Zeller reports financial ties with 480 Biomedical, Abbott Vascular, Angioslide, Bard Peripheral Vascular, Biotronik, Boston Scientific, Cook Medical, Cordis, Covidien, Medtronic, ReCor, Spectranetics, Straub Medical, TriReme, Veryan, VIVA Physicians, Volcano and W.L. Gore & Associates.