“Early data regarding atherectomy with the SilverHawk device (Ev3) indicate that diabetic patients do as well as non-diabetic patients when treated with atherectomy. DEFINITIVE LE, which is now completed, is the largest peripheral artery device study to date with 800 patients. As opposed to other modalities, these early results suggest that atherectomy is highly effective in the treatment of peripheral arterial disease in a heterogeneous real-world population,” James F McKinsey, chief of Vascular Surgery, Columbia University, New York, USA, told delegates at the Charing Cross Symposium in London.
McKinsey is a co-global principal investigator of the DEFINITIVE LE trial which set out to evaluate the intermediate and long-term effectiveness of stand-alone SilverHawk for endovascular treatment of peripheral arterial disease in the femoropopliteal and tibial-peroneal arteries. It assessed whether treated arteries remained unobstructed in patients with claudication and whether doctors could save the limbs of patients with critical limb ischaemia a year after treatment.
DEFINITIVE LE is a prospective, non-randomised, global study which has Clinical Events Committee and Steering Committee oversight and Core-lab verification of clinical data for both angiographic and Duplex images. Up to 800 subjects have been enrolled at more than 50 centres.
The primary endpoint of the study was primary patency at 12 months for claudicants (Rutherford clinical category 1–3 patients) or freedom from major unplanned amputation of the target limb through 12 months for those with critical limb ischaemia (Rutherford clinical category 4–6 patients).
Inclusion criteria were patients with Rutherford category 1–6; with ≥50% stenosis; with lesion length ≤20cm; reference vessel ≥1.5mm and ≤7.0mm. Exclusion criteria were severe calcification, in-stent restenosis and aneurysmal target vessel.
McKinsey presented data for 685 patients of which 73% were claudicants and 27% suffered from critical limb ischaemia. “There have been 296 patients who have appeared for six-month visits and 75 12-month visits to date,” he said.
In terms of patient demographics, the mean age of the patients was 70.4 ± 10.8; just under half the patients were female; 51.8% were diabetics and the majority of patients suffered from hypertension and hyperlipidemia.
Site-reported lesion characteristics revealed 947 lesions in 685 patients (mean 1.4 lesions per patient). Of these, 91.5 were de novo and the rest restenotic. Sixty three and a half per cent had mild or no calcification; 35.8% had moderate calcification. Total occlusions were 18.1% and mean diameter stenosis was 84.1%. Just under half of all patients were Rutherford clinical category 3, 18% were category 2 and 17% category 5. In addition, there were also 9% from category 4 and the others made up the total.
Interim analysis showed that from 235 claudicant patients with available data, 87.4% had primary patency. Of data from 95 diabetic patients, 89.7% had primary patency. Of 145 non-diabetic patients whose data was available, there was 85.6% primary patency. There was also data available for 63 patients who were at risk of amputation, but the analyses showed that 95.9% were free from amputation. There were also statistically significant improvements in secondary endpoints with reference to baseline for mean Rutherford clinical category, mean ankle brachial index. There were also improvements in pain, distance, speed and stair climbing as well as in the EQ5D index and VAS score with reference to baseline.
Roger Greenhalgh, Imperial College, London, writes in the CX33 Consensus Booklet that Giancarlo Biamino made a memorable intervention denouncing atherectomy. Biamino questioned why atherectomy was being introduced once more. Greenhalgh writes: “It sounds encouraging to actually remove the atheroma, but the results are not very reliable and this could be because the remaining lumen is far from smooth. This is the opposite of the unexpected excellent results after subintimal angioplasty. In the latter case, the blood flows along smooth walls in a rather unconventional way.”
