ISET Abstracts Shed Light on Novel Therapies for PAD

Two registry studies presented February 3, 2015, at the International Symposium on Endovascular Therapy (ISET) in Hollywood, FL, provide new insight on treatments for PAD. One focused on procedural outcomes of orbital atherectomy in critical limb ischemia (CLI) patients, and the other reported 1-year results from the IN.PACT Global Clinical Study on drug-coated balloon (DCB) treatment of femoropopliteal lesions.

Using data from the CONFIRM registries, Michael S. Lee, MD, of UCLA Medical Center (Los Angeles, CA), and George L. Adams, MD, MHS, of Rex Healthcare (Raleigh, NC), explored in a poster presentation whether lesion location impacts outcomes of CLI patients who undergo orbital atherectomy. The registries involved several orbital atherectomy systems—the Diamondback 360°, Predator 360°, and Stealth 360°—all manufactured by Cardiovascular Systems (St. Paul, MN).

Among 1,109 CLI patients (n = 1,544 lesions), 52.8% had above-the-knee or popliteal lesions and 47.2% had below-the-knee lesions. All were Rutherford class 4-6. Patients in the above-the-knee/popliteal group were more likely to be women (47% vs 37%; P < .001) and current smokers (31% vs 25%; P = .002) than those in the below-the-knee group; they also were less likely to have diabetes (64% vs 76%; P < .001) and renal disease (39% vs 45%; P = .03).

Lesion length did not differ between the 2 groups, though patients with above-the-knee or popliteal lesions had a higher percentage of severely calcified plaque (53.5% vs 46.9%; P = .02) and a lower percentage of minimally calcified plaque (2.1% vs 3.5%; P = .02).

Lesion Location Matters in Orbital Atherectomy

Preprocedural percent stenosis was lower in the above-the-knee/popliteal group (88 ± 12% vs 91 ± 11%). After treatment, the relationship reversed, such that below-the-knee lesions had lower percent stenosis. Final residual stenosis was similar between the 2 groups. Patients with above-the-knee or popliteal lesions had longer procedures and received more adjunctive therapies, such as balloons and stents.

Overall complication rates did not differ by lesion location, though perforation and spasm were more common and embolism less frequent in the below-the-knee group compared with the above-the-knee/popliteal group (table 1).

In an email with TCTMD, Dr. Lee reported that the researchers were “very pleased to see such favorable results in a typically high-risk patient population ([ie, those with] CLI) with challenging lesion locations.”

The higher rates of perforation and spasm in the below-the-knee group “could very well be explained by the inherent challenges [of treating such lesions], including advanced disease, challenging calcium burden, smaller vessel size, and tortuous vessels,” he said. “Higher rates of embolism in the [above-the-knee/popliteal group] could be explained by the generally poorer prognosis of these patients, including larger plaque burden, as well as the fact that there were more devices used in this patient cohort.”

In addition, Dr. Lee advised, “Meticulous technique and keeping the duration of the passes to a minimum are critical to the successful use of [orbital atherectomy].”

Plaque modification is particularly helpful in patients with below-the-knee lesions, when “the stakes are higher as there is the risk of limb loss,” he said.

DCB Therapy Does Well in Long Lesions

In an oral abstract, Gunnar Tepe, MD, of RoMed Clinic Rosenheim (Rosenheim, Germany), presented preliminary 1-year results on the first 655 of more than 1,500 patients enrolled in the IN.PACT Global Clinical Study. All patients received the IN.PACT Admiral DCB (Medtronic) and had lesions measuring at least 2 cm.

Most had claudication that was severe (58.2%) or moderate (27.3%) at baseline. Ischemic rest pain was present in 10.9% of patients, and 41.2% had diabetes. Mean lesion length was 12.23 cm, 35.8% of lesions were total occlusions, and 21.4% had in-stent restenosis.

One-quarter (24.7%) of patients underwent provisional stenting. Procedural success—defined as residual stenosis ≤ 50% without stenting or ≤ 30% with stenting—was achieved in 99.8% of patients. In all, 99.5% had procedural success in the absence of complications (death, major target limb amputation, thrombosis of the target lesion, or TVR prior to discharge).

Dr. Tepe reported 12-month outcomes both in the overall cohort and in patients with lesions ≥ 15 cm. Longer lesions had a mean length of 24.45 cm, 64.1% were total occlusions, and 35.4% required provisional stenting. Rates of TLR, TVR, and thrombosis were higher in patients with long lesions (table 2).

“Preliminary results from the IN.PACT Global Study indicate that the IN.PACT Admiral DCB is safe and efficacious in the treatment of real-world femoropopliteal lesions and continues to perform well in long lesions,” Dr. Tepe concludes in the ISET abstract.

Sources:
1. Lee MS, Adams GL. Impact of lesion location on procedural and acute outcomes in patients with critical limb ischemia treated with orbital atherectomy: a CONFIRM subanalysis. Presented at: International Symposium on Endovascular Therapy; February 3, 2015; Hollywood, FL.
2. Tepe G. New insights from real-world femoral-popliteal drug-coated balloon treatment: 1-year results from IN.PACT Global Study, including long lesions. Presented at: International Symposium on Endovascular Therapy; February 3, 2015; Hollywood, FL.

Disclosures:

• Drs. Lee and Adams report serving as consultants to Cardiovascular Systems.
• Dr. Tepe reports serving as a consultant to and on the advisory board of Covidien and Medtronic and receiving research support from Bard, B. Braun Medical, Biotronic, and Covidien and Medtronic.

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