After the Vienna ABSOLUTE trial RESILIENT is the only randomised controlled trial to report long-term results comparing primary stenting of the superficial femoral artery (SFA) and angioplasty.
As the optimal endovascular approach to SFA occlusive disease has been discussed very controversially for many years, these results are an important step towards establishing a missing basis of evidence and were received accordingly with great enthusiasm at two recent international vascular meetings: the British Society of Inventional Radiologists (BSIR) in Manchester in November 2008, and the VEITH meeting in New York a couple of weeks later. As in ABSOLUTE, primary femoropopliteal stenting was also in RESILIENT superior to angioplasty for symptomatic SFA occlusive disease and advantages were sustained at two years.
RESILIENT is an ongoing transatlantic multicentre trial that is conducted at 24 sites throughout the United States and Europe and involved 206 patients with life-style limiting claudication due to femoropopliteal lesions with a maximum length of 15 cm (mean lesion length 66 mm). The patients were randomised in a 1:2 ratio to either angioplasty alone (n=72) or angioplasty plus primary stenting (n=137) using C.R. Bards’ selfexpanding nitinol LifeStent (R). Primary endpoint was the clinically driven need for repeated revascularisations and secondary endpoints were initial procedural success, long-term vessel patency as assessed by duplex and sustained clinical improvement.
Dr. Barry Katzen, Founder of the Baptist Cardiac and Vascular Institute in Miami, Florida, and primary investigator of RESILIENT gave a detailed and comparative subgroup analysis of the European and US experience at BSIR in Manchester and an provisional interim analysis at 24 month follow-up at VEITH, both of which had not been published yet. “All patients have reached their 24 month follow-up by now”, Katzen said in New York, “however, some analyses are still being performed and are not available yet”. Essentially, the 12 month results showed a primary patency and freedom from repeated revascularisation in 80% and 87% of patients after primary stenting, respectively, whereas corresponding rates after angioplasty alone were 38% and 46% (P
Two-year results in favour of primary SFA stenting
“Ultrasound data were not recorded beyond 12 months”, Katzen explained long-term follow-up,”however, the Kaplan-Meier analysis of clinically driven revascularisations demonstrates an impressive advantage of primary stenting: at 24 months only 20% of stented patients had needed a repeated revascularisation, whereas it was 62% after angioplasty alone.” The rate of major adverse clinical events was similar in both arms at two years (20%) and showed, as at 12 months, a similar safety of primary stenting as compared to angioplasty alone. The overall stent-fracture rate at 18 months remained low at 3.8% (3.1% at 12 months) and fractures occurred almost exclusively in the middle segment of the SFA and often when 2 or more stents had been used.
These results were very impressive and illustrated the enormous progress in recent stent technology as compared to earlier generations of balloon-expandable stainless steel stents. “It is important to remember that RESILIENT compared primary stenting to angioplasty alone and not to the common clinical strategy of angioplasty with optional stenting in cases of dissatisfactory morphological results”, Katzen pointed out. Hence bail-out stenting after angioplasty was analysed as failure of angioplasty according to the intention to treat and, indeed, bail-out stenting was needed in about 40% of patients in the angioplasty arm. However, primary stenting has been tested before against a clinical strategy of angioplasty with optional stenting in the Vienna ABSOLUTE and ASTRON trials, respectively, and even in these trials, patients benefitted from primary stenting. “Although use of drug-eluting balloons is promising to improve the long-term durability of angioplasty in the SFA, their use is unlikely to change the need for initial bail-out stenting drastically. However, they may justify a policy of angioplasty with selective SFA stenting in the future, but randomised trials have to show that first”, Katzen expanded on the clear demonstration of limitations of stand-alone angioplasty of the SFA in RESILIENT. As bailout stenting was significantly more often necessary for longer or more calcified lesions, the results of RESILIENT are in line with results of the other randomised trials on the subject (FAST and the Vienna trials) indicating that primary stenting is the superior strategy for long and complex SFA lesions. “We may not have solved the ‘SFA conundrum’ yet, but the emerging evidence points into a clear direction”, Katzen concluded.
Results at European and US sites similar
An interesting subanalysis was given at BSIR comparing the European experience at Leipzig, Germany, and Vienna, Austria (n=55) with their US counterparts. The demographic and disease specific characteristics of the patients were comparable across the atlantic. While bail-out stenting was less often needed at the European sites (20% vs 40% overall) and, thus, the results in the angioplasty arm were somewhat better, the advantages of primary stenting were still of similar magnitude in the European experience as in the US at 12 months follow-up (Figure).
Thus the long-standing controversy over the right endovascular approach to SFA occlusive disease is shifting currently from anecdotal to high-level evidence. Importantly, the available evidence is fairly consistent across the trials so far, and emerging long-term results confer a comfortable degree of certainty. Finally, meaningful debate becomes possible and indeed one of the ‘great debates’ at the upcoming 31st Charing X meeting next April in London is dedicated to this important topic: it is certainly promising to become one of the exciting and entertaining highlights of the symposium.