OUTSIDE START Shows Effectiveness of Bridge Therapy Using Cilostazol

May 8, 2015—The Society for Cardiovascular Angiography and Interventions (SCAI) announced findings from the OUTSIDE START study demonstrating that patients who received a paclitaxel-eluting stent (PES) that carried a higher stent thrombosis risk and were given the shorter-acting antiplatelet drug cilostazol before a surgical procedure safely transitioned off of dual-antiplatelet therapy (DAPT) to reduce the risk of bleeding during the procedure. 

Principal Investigator Charles Laham, MD, presented “OUTSIDE START Cilostazol Bridging Study: 8-Year Experience With Outpatient Cilostazol Bridging in High Stent Thrombosis Risk Paclitaxel Drug-Eluting Stents in Patients Having Surgery During the Proven At-Risk Period” as a late-breaking clinical trial at the SCAI 2015 scientific sessions being held May 6–9 in San Diego, California. Dr. Laham is an interventional cardiologist at Holy Family Memorial’s Heart & Vascular Center in Manitowoc, Wisconsin.

Dr. Laham noted in the SCAI announcement, “Patients on DAPT can be a challenge to manage during surgery because there are significant risks of a stent clotting if DAPT is stopped, while there are also significant risks of bleeding if it is not stopped. To manage these ‘double jeopardy’ risks, we evaluated bridge therapy, which allows the patient to transition off of DAPT for their surgical procedure using a short-acting antiplatelet drug.” 

In the study, patients stopped DAPT 8 days before the operation. Seven days before the operation, they began receiving 100 mg of cilostazol twice per day or, alternatively, 50 mg if they were undergoing high-bleeding-risk surgery or were intolerant of the full dose. Lower-risk patients stopped cilostazol 24 to 30 hours before the surgical procedure and resumed DAPT 12 to 24 hours after surgery. Patients at a higher risk of bleeding during surgery stopped cilostazol 54 to 60 hours before surgery and resumed DAPT 24 to 36 hours after surgery. The investigators considered patients to be “fully bridged” if they received at least 600 mg of cilostazol before surgery and resumed DAPT by at least 48 hours after surgery.

In total, 108 patients with a PES had 183 surgeries with a cilostazol bridge from 2005 to 2012. The investigators measured rates of adverse events during bridging and within 30 days after surgery. Of the 183 surgical procedures, 171 were fully bridged with no adverse events. In 12 surgeries, the patients did not receive the full cilostazol bridge/DAPT resumption protocol, and of those, four (33%) experienced an adverse cardiac event. 

“Even in high-risk patients, we found cilostazol bridging is effective without the risk of adverse events or bleeding within 30 days of an operation, provided the protocol timeline was followed,” stated Dr. Laham. 

The study involved only patients who had received higher-thrombotic-risk PES but did not include patients with the newest generation of stents. Despite having similar successes with bridging of smaller numbers of other stent types in the main OUTSIDE patient study, larger studies should be conducted to confirm whether the bridge strategy is effective for larger numbers of patients with other types of drug-eluting and bare metal stents, as they are outside the scope of the current study, advised the investigators.