Drug Stents and Surgery
Drug-eluting stents (DES) are a medical success story: In the four years since they were approved, in-stent restenosis rates have gone from the 25%-30% associated with bare-metal stents to the single digits.
Thanks to this track record, the world market for stents has doubled to $5 billion—despite the fact patients with DES must take aspirin or clopidogrel to prevent thromboses.
It’s easy to forget not all questions concerning DES have been answered, despite their wide acceptance and good overall outcomes.
One concern is discontinuation of antiplatelet therapy for DES patients who require noncardiac surgery.
In the November-December 2007 Journal of Hospital Medicine, senior author Amir Jaffer, MD, and colleagues at the Cleveland Clinic in Ohio studied the relationship between a patient’s time on antiplatelet medication and the consequences of discontinuing those agents in preparation for surgery.
“This is a common clinical conundrum,” says Dr. Jaffer, director of the Cleveland Clinic’s Internal Medicine Preoperative Assessment Consultation and Treatment (IMPACT) Center. “We face this question almost every day in our practice relative to perioperative care.”
Patients slated for noncardiac surgery are seen first at the IMPACT center, where hospitalists conduct the preoperative evaluation.
Data show that patients with bare-metal stents run a high risk of stent thrombosis if they undergo noncardiac surgery within two to six weeks of stent placement.
But information on DES is hard to come by, “so we decided to try to get a handle on the safety of stopping these drugs,” says Dr. Jaffer.
The authors, led by Daniel J. Brotman, MD, studied all patients who had undergone DES placement and were evaluated for noncardiac surgery at the IMPACT Center from July 2003 to July 2005. They examined 30-day rates of postoperative myocardial infarction (MI), DES thrombosis, major bleeding, and all-cause mortality—all relative to how long the patient had been on and off antiplatelet therapy.
The type of surgery each patient underwent was classified by invasiveness and anticipated blood loss, according to the system developed by L. Reuven Pasternak, MD, vice dean, Bayview Campus, Johns Hopkins University in Baltimore, and his colleagues.1
The categories range from one, which includes cystoscopy, breast biopsy, and other minor procedures that involve little if any blood loss, to five, which encompasses highly invasive procedures with anticipated blood losses in excess of 1,500 cc, such as major vascular repair.
A total of 114 patients met the study criteria. Seventy-five (66%) of the patients were men, and the median age was 71.
The most common comorbidities were diabetes (in 41% of patients), a history of coronary bypass (34%), and chronic renal insufficiency (20%). Most patients (73%) received sirolimus (Rapamune) stents; 28% received paclitaxel (Onxol) stents; and 33% had more than one DES.
Of the patients studied, 69 (61%) underwent surgery more than 180 days after receiving their DES; 30 (26%) had their procedures within 91-180 days of receiving the stent; and 15 (13%) had their operations within 90 days of stenting.
The most common procedures were major orthopedic surgeries such as hip replacement (34.2% of patients), and ophthalmologic procedures like cataract removal (26.3%).
