Much controversy has developed over the past year about the safety and potential complications of drug-eluting heart stents, increasing the risk of possible fatal blood clots, even years after an angioplasty procedure.
However, a new Canadian study led by investigators from Ontario’s Institute for Clinical Evaluative Sciences (ICES) and McMaster University’s Program for Assessment of Technologies in Health, tells a different story.
Drug-eluting stents were found to be most effective in reducing the need for repeat angioplasty procedures or bypass surgery in angioplasty patients at the ‘highest risk’ for a renarrowing of the artery around the stent, without significantly increasing the rate of death or risk of heart attack. Lead Author, ICES Sr. Scientist, Dr. Jack Tu says, “This is good news, reassuring patients and cardiologists about the safety of drug-eluting stents when used in appropriate individuals. Our results also suggest physicians should be selective in using drug-eluting stents, offering them to angioplasty patients who are at the highest risk for repeat cardiac procedures.”
Reporting in the October 4th issue of the prestigious New England Journal of Medicine, the large Canadian study conducted at ICES, in collaboration with cardiologists and researchers from Sunnybrook Health Sciences Centre and the University of Toronto, looked at over 3,700 unique matched pairs of Ontario patients who received drug-eluting stents (DES) or more conventional bare metal stents (BMS) during angioplasty. Using data from the Ontario Cardiac Care Network’s (CCN) population-based angioplasty registry, and accounting for differences in patient characteristics, investigators analyzed the outcomes of patients having angioplasty in Ontario between December 2003 and March 2005 for the ‘real-world’ effectiveness of DES. The results:
– DES reduced the need for a second procedure to unblock or bypass a clogged artery by 30% relative to BMS, from 10.7% to 7.4%.
– After 3 years of follow up, mortality was reduced for DES patients (5.5%) relative to BMS (7.8%).
– After 2 years of follow up, rate of heart attack for DES patients was marginally but not significantly higher at 5.7% vs. 5.2% in BMS patients.
– The reduction in the need for repeat procedures (i.e. target vessel revascularization (TVR rate)) was greatest in patients with two or three risk factors (e.g. diabetes, small vessels, or long lesions) for renarrowing of the artery, whereas lower and intermediate risk patients did not have significant reductions in TVR rates.
Co-Author, Dr. Eric Cohen, Medical Officer for CCN says, “Drug-eluting stents have been at the centre of a very active worldwide debate regarding issues of safety, degree of benefit and funding of a relatively expensive new technology. This study will be very helpful to clinicians, administrators and policy-makers in clarifying these issues as it confirms that using drug-eluting stents in patients at high risk for renarrowing is both effective and safe.”