A Medical Device Daily

As the 56th annual edition of the American College of Cardiology's (ACC; Washington) scientific sessions got underway in New Orleans, the flow of new products and trial results appeared to be at a record high.

Abbott Laboratories (Abbott Park, Illinois) took the opportunity to unveil the results of several studies at the conference. The company reported what it said were positive 30-day results from two studies to confirm that carotid stenting can be performed with positive results by physicians with a variety of background experience in real-world settings in patients who are not favorable candidates for surgery.

Interim results from the first 1,500 patients enrolled in EXACT (Emboshield and Xact Post Approval Carotid Stent Trial) and from the first 600 patients enrolled in CAPTURE 2 (Carotid ACCULINK/ACCUNET Post Approval Trial to Uncover Rare Events) were presented by William Gray, MD, of Columbia University Medical Center (New York), in a late-breaking clinical trial session.

The primary endpoint of death, stroke and heart attack at 30 days was 4.6% in EXACT and 5.2% in CAPTURE 2. Further, results from EXACT and CAPTURE 2 demonstrated a low rate of 30-day major stroke and/or death in patients treated with Abbott's carotid stent systems (1.8 % in EXACT, 1.3% in CAPTURE 2). The EXACT post-approval study uses Abbott's Xact rapid exchange carotid stent system and Emboshield BareWire rapid exchange embolic protection system. CAPTURE 2 uses the company's Acculink carotid stent system and Accunet embolic protection system.

"The results from these two studies reaffirm that carotid stenting is a safe, effective minimally invasive treatment option for patients with carotid artery disease who may be at risk of experiencing adverse events from surgery," said Gray. "The results also suggest that patient outcomes are improving over time as the practice of carotid stenting increases."

Carotid artery stenting is a minimally invasive treatment option for patients who require intervention and who are at high risk for complications from carotid endarterectomy, an invasive surgical procedure. Carotid artery stenting is performed by delivering a stent on a catheter through the femoral artery in the groin. The catheter is maneuvered through the patient's vasculature to the carotid artery. The stent, which is designed to prevent arterial plaque and debris from breaking off and blocking blood flow to the brain, is then expanded at the site of the blockage. The embolic protection filter captures and removes any debris that has become dislodged during the carotid stenting procedure.

In other ACC news: Boston Scientific (Natick, Massachusetts) reported one-year results from its below-the-knee (BTK) CHILL study, which evaluated the performance of the PolarCath peripheral dilatation system for the dilatation of stenotic lesions in infrapopliteal arteries (arteries below the knee) when treating the whole leg.

Results were presented by principal investigator Tony Das, MD, director of peripheral interventions at Presbyterian Heart Institute (Dallas).

One-year results of the BTK CHILL study, a prospective, multi-center trial with 111 limbs treated in 108 patients at 16 sites in the U.S., include an 85% freedom from amputation rate and a 97% procedural success rate (a decrease in vessel narrowing to less than 50%), resulting in improved blood flow.

The company said these outcomes are particularly encouraging in light of the severity of disease in these patients. The majority of patients in this study exhibited tissue loss at baseline with nonhealing ulcers or focal tissue loss reported in 66% of the limbs and gangrene reported in 37% of the limbs (some patients reported both focal tissue loss and gangrene).

"Almost 70% of patients with critical limb ischemia undergo amputation as the initial treatment," said Das. "The 12-month results from the BTK CHILL study support the effectiveness of the PolarCath System, which offers a valuable alternative to amputation or invasive surgical bypass procedures in patients who have this painful, historically difficult-to-treat condition."

Two-year results from the Medtronic (Minneapolis) ENDEAVOR III trial confirm the positive clinical profile of the Endeavor drug-eluting coronary stent and bring to nearly 1,300 the number of Endeavor patients who have at least two years of follow-up, according to the company. Significantly, the company said, among those 1,300 Endeavor patients, there have been no reported cases of late stent thrombosis using the independent, pre-specified clinical trial protocol definitions for thrombosis.

Those in the 436-patient ENDEAVOR III trial are being followed out to five years. The clinical data reported at ACC as part of the study design indicate that the Endeavor stent continues to exhibit an excellent safety profile while delivering sustained efficacy and a low need for repeat procedures that is consistent with the overall Endeavor clinical program.

At two years, the MACE rate was reported to be 9.3% for Endeavor and 11.6% for Cordis' (Miami Lakes, Florida) Cypher stent, also studied in the ENDEAVOR III trial. There was no statistically significant difference in the need for repeat procedures, or Target Lesion Revascularization (7% and 4.5% for Endeavor and Cypher, respectively), or all-cause mortality (1.6% for Endeavor and 4.5% for Cypher). However, fewer patients experienced heart attacks when treated with the Endeavor stent (0.6% vs. 3.6% for Cypher) and the combined rate of heart attack and death also was statistically significantly lower among patients randomized to the Endeavor stent (2.2% vs. 7.1% for Cypher).

Medtronic will present additional long-term data on Endeavor in the coming months. At the EuroPCR meeting in May, Medtronic will provide updated four-year and three-year results from the ENDEAVOR I and ENDEAVOR II trials respectively, as well as new data on the next-generation Endeavor Resolute drug-eluting stent. Results from the ongoing ENDEAVOR IV trial, another large randomized trial (1,548 patients) evaluating Endeavor against the Taxus stent made by Boston Scientific are expected to be presented in the fall.