NEW YORK — Cancer patients and survivors who develop acute coronary syndrome or myocardial infarction need a different approach to stent treatment than do conventional coronary disease patients.
Drug-eluting coronary stents should be avoided, and bare-metal stents should be used judiciously in patients with a history of cancer, Dr. Jean-Bernard Durand said at a symposium on cardiovascular disease in cancer patients sponsored by the University of Texas M.D. Anderson Cancer Center.
Cancer patients are often highly prothrombotic, and they face a substantially increased risk from coronary stent thrombosis. As a result, “we have made a big change [in our use of coronary stents] and it's made a big difference; our patients are doing much better,” said Dr. Durand, a cardiologist and medical director of cardiomyopathy services at the University of Texas M.D. Anderson Cancer Center in Houston.
Patients with a history of cancer who present with a symptomatic coronary thrombosis never receive a drug-eluting stent, and get a bare-metal stent only for lesions that are eccentric, are at a bifurcation, or are heavily calcified. Symptomatic patients with simpler coronary lesions are treated with balloon angioplasty only, and patients with significant coronary obstructions who are not acutely symptomatic are treated only with aggressive medical management, Dr. Durand said in an interview.
In addition, patients who receive a bare-metal stent are treated only with aspirin, not clopidogrel or ticlopidine. Patients with a history of cancer often have an abnormally low level of platelets, and their platelets also often show unusual patterns of reactivity and clotting. “The platelets tend to form loose clots, so an 80-mg/day dosage of aspirin seems to be enough to prevent clots,” Dr. Durand said at the meeting, which was also sponsored by the American College of Cardiology and the Society of Geriatric Cardiology.
His group also uses a thromboelastograph (TEG) to quantitatively assess platelet function and clot formation in patients. “We use it to determine how aggressively to treat patients” with anticoagulants, he said.
Dr. Durand and his associates documented the importance of aspirin therapy in cancer patients with acute coronary syndrome (ACS) in a review of 70 cancer patients who developed ACS and were managed at M.D. Anderson during 2001 (Cancer 2007;109:621–7). The analysis included 43 patients (61%) with normal platelet counts of greater than 100,000/mcL, and 27 patients (39%) who were thrombocytopenic, with platelet counts of less than 100,000/mcL. The median platelet count in the thrombocytopenic group was 32,000/mcL.
Immediately after their ACS event, thrombocytopenic patients were significantly less likely to be treated with aspirin than were nonthrombocytopenic patients (37% vs. 74%, respectively), or with a β-blocker (41% of thrombocytopenic patients, compared with 74% of those without thrombocytopenia).
In a multivariate analysis that controlled for other variables, patients who did not receive aspirin were more than 18-fold more likely to die during the first 7 days after their event than those given aspirin.
Dr. Durand conceded that this study involved relatively few patients and brief follow-up. But a subsequent analysis of about 500 patients and longer follow-up by the M.D. Anderson group found that cancer patients had significant benefit from aspirin therapy after ACS events regardless of whether they were thrombocytopenic, he said.
Cancer patients are often highly prothrombotic and at increased risk from coronary stent thromobosis. DR. DURAND