Treatment of Most Endovascular Lesions Feasible with 4-Fr Devices

PARIS, France—Use of 4-Fr devices is feasible for the majority of endovascular interventions, achieving similar technical success and primary patency to that of 6-fr devices, even in calcified blockages, according to results presented Tuesday, May 21 at EuroPCR 2013.

For the 4EVER study, researchers led by Marc Bosiers, MD, of AZ St. Blasius (Dendermonde, Belgium) investigated the safety and efficacy of the 4-fr Pulsar Stent System (Biotronik, Berlin, Germany) in 120 patients with superficial femoral artery (SFA) lesions. Pulsar-18 stents are made of ultrathin nitinol struts coated with a silicon carbide layer meant to improve the stent's hemocompatibility and biocompatibility. Pulsar-18 is available in diameters of 4 to7 mm and lengths of 20 to 200 mm lengths deliverable through a 4-Fr sheath.

Patients in the study were Rutherford category 2 to 4, with SFA lesions that were either stenosis greater than 50% or occlusions. The majority of patients (83.33%) had intermittent claudication, while the rest had critical limb ischemia. Almost one-third of lesions (30.93%) were calcified. Closure devices were not used.                                       

The rate of important hematoma at the puncture site was 3.34%, with no surgical repairs required. Three of the 4 patients with hematoma were on warfarin. “So probably that’s the contraindication to go for manual compression with  a 4-Fr device,” Dr. Bosiers said.

Manual Compression Time Reduced

Mean manual compression time was low at 8.12 minutes, ranging from a minimum of 2 to a maximum of 15 minutes. This compares favorably with compression times from the literature of 9.2 to 22 minutes achieved with 6-Fr procedures.

At 12 months, primary patency was 81.4% with 4-Fr interventions, with a 12-month freedom from TLR rate of 89.3%.

“When we started this trial, if you would’ve asked me where will you end up [in terms of primary patency], I would’ve probably said around 65% to 70%, but I was amazed to see [the actual result],” Dr. Bosiers remarked.

Primary patency was not dissimilar between the Astron Pulsar and Pulsar-18 stent systems (85.2% vs. 73.4%; P = 0.236). Combined stent usage achieved a rate of 100%. Patency rates were the same whether lesions were classified as stenosis (83.5%) or occlusion (73.2%; P = 0.384) and whether lesions were (80.2%) or were not (82.0%) calcified (P = 0.659). Dr. Bosiers commented that operators in the trial did not have to switch to a 6-Fr system to cross a heavily calcified lesion. “Never,” he said. “Success was 100%.”

Fractures of Little Impact

The overall stent fracture rate at 12 months was 4.17% (n = 120), with 115 marked by no strut fractures (Class 0), 1 Class I fracture (single tine fracture), 3 Class III fractures (with preserved alignment of the components), and 1 Class V (fracture in a transaxial spiral configuration). The rate of loss of primary patency due to stent fracture was 1.67% (2 of 120).

Dr. Bosiers explained that using 4-Fr procedures, the vast majority of endovascular interventions are possible, including:

  • Lesion passages
  • Balloons (6 mm - 28 cm)
  • Drug-eluting balloons (5 mm - 12 cm)
  • Coronary stents
  • DES
  • Nitinol stents (7 mm - 20 cm)
  • Rotablator

Meanwhile, procedures that are still not possible with a 4-Fr approach include:

  • Atherectomy (Silverhawk, Laser, Jetstream)
  • Outback/Frontrunner
  • “Kissing” bifurcation intervention
  • Thromboaspiration
  • Coral reef lesions

Nevertheless, this means that 4-Fr access is “sufficient for the vast majority of endovascular treatments,” Dr. Bosiers said, adding that they are possible “with less access complications (save coumarines), no need for expensive closure devices, and less time for manual compression.”

When pressed by a panel member regarding his preference over the main criteria for choosing a stent—the size of the required access or the performance of the device—Dr. Bosiers replied, “no doubt the performance of the stent is what you favor, but the nice thing about a 4-Fr system is you can use those type of stents all the way from the external iliac artery all the way down to the tibials.”

He added that radial force, meanwhile, may be overrated. “What you need in the femoral artery is sufficient radial force to prevent recoil, but you’re not helped with progressive outward radial force which induces more intimal hyperplasia,” Dr. Bosiers said.


Bosiers M. 4EVER trial: 1-year results. Presented at: EuroPCR; May 21, 2013; Paris, France. 



  • Dr. Bosiers reports serving as a consultant for Abbott, Biotronik, Boston Scientific, Cook, Covidien, Intact Vascular, Medtronic, and Stentys, and co-founding Argonauts Partners.


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