SCAI: Iliac stents gain MOBILITY in treatment of PAD
Iliac artery disease is a form of peripheral artery disease (PAD) that can progress to the point of impacting walking ability, and can result in chronic pain and even permanent disability. Historically, iliac artery stent trials for treatment of intermittent claudication or critical limb ischemia (CLI) have excluded highly calcific lesions, so these trials may not be representative of real-world patients, explained Michael R. Jaff, DO, medical director of the Vascular Ultrasound Core Laboratory at Massachusetts General Hospital in Boston, who presented the results on behalf of the MOBILITY researchers. “As a result our inclusion of patients with dense calcifications is a key takeaway for this study,” he added during a press conference.
“This was an interesting study in that it further informs physicians about how to use endovascular devices in PAD,” Jaff said.
MOBILITY is a prospective, two-arm, non-randomized, multicenter trial of iliac artery stenting in patients with intermittent claudication and CLI (Rutherford Becker [RB] 2-4), evaluating the safety and effectiveness of the Absolute Pro peripheral self-expanding stent system and the Omnilink Elite peripheral balloon-expandable stent system (Abbott Vascular, Santa Clara, Calif.).
The researchers enrolled a total of 304 patients with 384 lesions (Absolute Pro in 151 patients/181 lesions and Omnilink Elite in 153 patients/203 lesions) between November 2009 and December 2010. Specifically, the study assessed patients with iliac artery disease—either at the common iliac artery, external iliac artery or both. Typically, according to Jaff, the strategies for the management of iliac artery disease are “different” depending on the location of the lesion.
Almost all of the patients had multilevel PAD, including those with aortoiliac and femoropopliteal diseases, Jaff explained.
At the start of the trial, these two devices were off-label to treat iliac artery disease. The primary endpoint for each arm was the composite major adverse event (MAE) rate at nine months, defined as all-cause death, MI, major amputation and clinically-driven target lesion revascularization (CD-TLR). The secondary endpoints were restenosis, CD-TLR, changes in walking ability and RB between baseline and nine months. RB classifies severity of CLI.
The MAE rate at nine months was 6.1 percent for Absolute Pro and 5.4 percent for Omnilink Elite, both significantly below the pre-specified objective performance goal of 19.5 percent, Jaff reported. “Thus, there is no real concern from a safety perspective,” Jaff said.
Although moderate to severe calcification was noted in 90 percent of all lesions, restenosis rates were 8.4 percent and 9 percent for AP and Omnilink Elite.
Even though 99 percent of the patients had multilevel PAD, walking ability significantly improved, according Jaff. Walking ability was designated among the quality-of-life benefits.
For the Absolute Pro, the walking distance at baseline was 14 percent, rising to 55.7 percent at nine months; the walking speed at baseline was 17.9 percent, rising to 50.6 percent at nine months; and stair climbing at baseline was 22.7 percent, rising to 59.2 percent at nine months. For the Omnilink Elite, the walking distance at baseline was 17.5 percent, rising to 56.6 percent at nine months; the walking speed at baseline was 20.1 percent, rising to 47.6 percent at nine months; and stair climbing at baseline was 26 percent, rising to 60.4 percent at nine months.
The improvement of RB 1 category was noted in 93.9 percent and 89 percent of limbs for the Absolute Pro and Omnilink Elite. In fact, 60 percent of patients in both arms had a RB of zero, which means they had unlimited walking distance, and another 25 percent had a RB 1, which is “quite impressive,” said Jeff. Finally, freedom from CD-TLR by Kaplan-Meier analysis was 97.1 percent and 94.9 percent for Absolute Pro and Omnilink Elite, respectively.
The researchers concluded that both stents met the primary endpoint, and “significant improvements in walking ability and Rutherford Becker classification with low restenosis and CD-TLR rates, regardless of extensive calcification, were noted in both arms of this trial, demonstrating that Absolute Pro and Omnilink Elite are effective in treating iliac artery disease in a real-world population.”
For clinical practice, Jaff interprets the results to mean that “aorto-bi-femoral bypass surgery should not be a first line, or even a second-line approach, but instead, a last ditch treatment for those with iliac artery disease.”
He said that these data will be used for submission to the FDA to become on-label devices. During the press conference, SCAI President Christopher J. White, MD, echoed the "confirmatory" nature that this study, adding that there "has been a true need in the cath lab for on-label devices."
In March, the Absolute Pro gained FDA approval for the treatment of iliac artery disease, largely due to the support of the MOBILITY results.