The recent controversy over the use of paclitaxel in the peripheral vasculature has clouded the larger debate over whether bypass is superior to endovascular therapies for the lower limbs. However, a new study suggests that nitinol stents provide a feasible alternative to bypass even for lesions of the femoropopliteal artery that are 30 cm in length. The results of this study provide a much-needed boost to device therapy for this indication, which has been under intense pressure since the publication of the so-called Katsanos study in December 2018.
The debate over the use of paclitaxel for drug-coated balloons and drug-eluting stents flared upon the publication of the Katsanos study, which suggested higher rates of mortality associated with these devices. That analysis sustained a hit recently with the publication of a study in Germany of more than 64,000 patients treated between 2007 and 2017, with 11-year data suggesting no significant difference in mortality. Whether the German study has helped revive utilization of these devices in the U.S. is unclear, however.
This latest study taking up the question of stenting vs. bypass was conducted at Paracelsus Medical University in Salzburg, Austria, and required randomization of 110 limbs in 103 patients to the two treatments. The mean lesion length was roughly 276 mm in each group, and critical limb-threatening ischemia rates were identical (49%). The authors noted that the only major randomized, controlled trial comparing bypass and angioplasty in lower limb ischemia was published in 2005. The study “still influences guidelines to a significant extent,” the authors said.
Guidelines more restrictive for lesion length
That previous study determined that angioplasty and bypass provided no significantly different outcomes in terms of amputation-free survival or quality-of-life measures, although the angioplasty approach was significantly less expensive. The authors of the Austrian study also noted that several guidelines have been drafted, including the Trans-Atlantic Inter-Society Consensus (TASC), which recommends bypass for femoropopliteal lesions longer than 15 cm, while the European Society of Cardiology has recommended an endovascular-first approach for lesions shorter than 25 cm.
The Austrian study limited enrollment to those with TASC II type C and D lesions and used a combined primary endpoint of technical success as well as primary, primary assisted and secondary vessel patency. Secondary endpoints included limb salvage, survival, local and systemic complications and clinical improvement. Enrollees had to be at least 30 years of age and be symptomatic for at least two months. Those deemed too frail to undergo bypass were excluded, as were those who had previously undergone ipsilateral bypass surgery. The patient screening process was conducted between March 2016 and March 2018 and so antedated the paclitaxel controversy.
At two years, the majority of the bypass patients were treated with harvested greater saphenous veins from the alternate leg, but technical success was seen in only 87% of the stented group vs. 100% in the bypass group. One of the issues with the stented arm was that the technical failures were in seven vessels with a mean length of 341 mm, five of which were severely calcified, while three lesions were recurrences of prior angioplasty. Three of this group of seven patients ultimately were bypassed.
Primary vessel patency at 24 months was seen in 60% of the stented patients vs. 56% of the bypass patients, while primary assisted (63% stent and 71% bypass) and secondary patency (72% of stent patients and 73% bypass) both slightly favored bypass numerically. However, none of these differences reached statistical significance. Freedom from total lesion revascularization was 75% in the stented group and 67% for bypass at 24 months, while limb salvage and survival were not significantly different under an intent-to-treat analysis. Limb salvage numerically favored stenting (100%) over bypass (88%), however.
Overall complications were seen in 21 of the stented group vs. 25 in the bypass arm, and patients with at least one complication numbered five in both arms. Minor amputation also favored the stented group (four) rather than the bypass group (five), although there were seven instances of vessel perforation in the stent arm vs. none in the bypass arm.
The authors noted that while the clinical improvement in the bypass group was significantly better than in the stented group, the data suggest that a stent-first strategy in these long lesions “may be reasonable,” although longer term outcomes are needed to corroborate. The article is in press in JACC: Cardiovascular Interventions under the title, “Nitinol Stent versus Bypass in Long Femoropopliteal Lesions: 2-Year Results of a Randomized, Controlled Trial.”
Author of editorial says not so fast
In an accompanying editorial, Matthew Menard of Brigham and Women’s Hospital in Boston said the investigators “are to be commended for a well-conceived and designed effort,” as well as for the level of detail provided in the write-up. However, while Menard was complimentary overall, he noted that the patency rates for bypass in this study were lower than expected and asked whether the authors would have arrived at a different conclusion had the bypass group fared per expectations.
Menard said the data are insufficient to predict which patients with preclinical disease are likely to progress to limb-threatening disease, which is paralleled by ignorance of which patients are likely to suffer from post-intervention hyperplasia of the intima. There is also a need for some method of measuring real-time perfusion, Menard said, adding that one helpful development would be an abatement of “the rigidity of the endovascular vs. open debate.”
The authors acknowledged that many physicians have adopted an endovascular-first strategy, and Menard said there is a need to clarify the respective roles of both approaches. He noted that drug therapy has done much to stave off some of these cases but made note of “the burgeoning interest our non-interventional cardiology and vascular medicine colleagues are developing” for research into peripheral artery disease. Menard said the conclusions drawn by the authors are “unsupported by the data and [are] speculative at best,” but he applauded “their dedication to helping clarify this important clinical question.”