Polymer-free Drug-Coated Coronary Stents in Patients at High Bleeding Risk

Janet Kairu, Mercer University College of Pharmacy

According to the American College of Cardiology and the American Heart Association, the aging world population faces a coming pandemic of high-risk coronary artery disease (CAD).  They suggest that patients with CAD have three therapeutic options which are based on objective clinical outcome: medical therapy and risk factor modification (Medicine), and two forms of revascularization, coronary artery bypass graft surgery (CABG), and percutaneous coronary intervention (PCI). [1]

Percutaneous coronary intervention (PCI) is considered a common procedure to treat coronary artery stenosis.  A review of four studies demonstrated that PCI does not reduce the risk of death or myocardial infarction when performed to patients with stable angina. [2]

Table 1.

Title: Polymer-free Drug-Coated Coronary Stents in Patients at High Bleeding Risk. [3]
Design Randomized, double-blind trial, N = 2466
Objective To study a polymer-free and carrier-free drug-coated stent that transfers umirolimus (also known as biolimus A9), a highly lipophilic sirolimus analogue, into the vessel wall over a period of one month
Study Groups Patients were randomly assigned in a 1:1 ratio to undergo PCI with the Bio Freedom polymer-free umirolimus-coated stent or a similar bare-metal stent (BMS)
Methods Drug-coated stents were compared with bare-metal stents in patients with a high risk of bleeding who underwent percutaneous coronary intervention (PCI).  All patients received one month of dual antiplatelet therapy.
Duration December 2012 through May 2014
Primary Outcome Measure The primary safety end point, tested for both noninferiority and superiority, was a composite of cardiac death, myocardial infarction, or stent thrombosis.  The primary efficacy end point was clinically driven target-lesion revascularization (TLR).
Baseline Characteristics
Number of events Drug-Coated Stent

(n = 1221)

Bare-Metal Stent

(n = 1211)

Age, (yrs.) 75.7 +/-9.4 75.7 +/- 9.3
Female sex, no. (%) 364 (29.8) 374 (30.9)
Body mass index, kg/m2 27.5 +/- 4.8 27.2 +/- 4.6
ST-elevation myocardial infarction (STEMI), no. (%) 57 (4.7) 48 (4.0)
Non ST-segment elevation myocardial infarction (NSTEMI), no. (%) 273 (22.4) 281 (23.2)
Unstable angina, no. (%) 177 (14.5) 193 (15.9)
Stable CAD, no. (%) 714 (58.5) 689 (56.9)
Previous PCI, no. (%) 270/1215 (22.2) 265/1208 (21.9)
Multiple diseases, no. (%) 755/1201 (62.9) 738/1198 (61.6)
End Point, number of events (% of patients) Drug-Coated Stent      (n = 1221) Bare- Metal Stent (n = 1211) Hazard Ratio

(95% CI)

p- value
Primary safety end point: cardiac death, myocardial infarction, or stent thrombosis 112 (9.4) 154 (12.9) 0.71 (0.56-0.91) 0.005
Primary efficacy end point: clinically driven TLR 59 (5.1) 113 (9.8) 0.50 (0.37-0.69) 0.001
Adverse Events
Serious Adverse Events: Not applicable
Percentage that Discontinued due to Adverse Events: Not applicable
Study Author Conclusions Among patients at high risk for bleeding who underwent PCI, a polymer-free umirolimus-coated stent was superior to a bare-metal stent with respect to the primary safety and efficacy end points when used with a one-month course of dual antiplatelet therapy.


The results of this trial indicate that clinical outcomes following biolimus A9 drug coated stent implantation are superior to bare metal stents in patients with high bleeding risk and able to take only one month of dual antiplatelet therapy.  There was a significant reduction in myocardial infraction (MI) and target-lesion revascularization (TLR), with similar rates of stent thrombosis.  A higher benefit was noted in patients presenting with acute coronary syndrome, no renal failure on admission, lower CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association Guidelines) risk scores, and in those not anemic or requiring a transfusion during admission.

The authors point out that the biolimus A9 stent is not a bioabsorbable stent, but rather a drug coated stent where the drug is coated to the abluminal surface of a stainless steel stent with a solvent.  The drug is more lipophilic than contemporary limus agents and is essentially absorbed almost entirely in 30 days, leaving behind a plain BMS.  Stent thrombosis rates were higher than typically seen with second-generation everolimus-eluting stents.



  1. American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Society for Cardiovascular Angiography and Interventions. Circulation. 2015; Accessed October 24, 2015
  1. Bobbio M. [Patients facing with the decision to undergo percutaneous coronary intervention]. Recenti Prog Med. 2015;106(3):113-7.
  1. Urban P, Meredith IT, Abizaid A, et al. Polymer-free Drug-Coated Coronary Stents in Patients at High Bleeding Risk. N Engl J Med. 2015

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