Scores of interventional cardiologists (ICs) across the country are now relieved on the long-term safety of the Cordis' Cypher Sirolimus-eluting Coronary Stent, in terms of fatality, myocardial infarction (head attacks) and stent thrombosis which is comparable to that of bare metal stents.

The reports by New England Journal of Medicine (NEJM) have confirmed the long-term efficacy of the Cypher Stent in substantially reducing the need for another interventional procedure (revascularization) compared to bare metal stents.

According to Dr Samuel Mathew Kalarickal, Interventional Cardiologist, Lilavati Hospital, Mumbai and director - Interventional Cardiologist, Apollo Hospitals, Chennai, these studies provide immense confidence to both specialists and their patients.

Clinical data covered by NEJM were presented previously at the US Food and Drug Administration advisory panel hearing in December 2006 on the safety of drug-eluting stents.

The current Cypher stent database, which includes more than 45,000 patients represents the broadest clinical data of any drug-eluting stent (DES). The studies evaluating the Cypher Stent in higher risk patients not currently within the approval labeling, including those with diabetes and lesion subgroups, will continue to be a focus of ongoing clinical research, stated Dr Mathew.

Cordis has been supporting several randomized clinical trails as well as 'real world' registries to gather data about the use of the Cypher Stent. 'While data from registries, such as the one from Sweden in the latest edition of the NEJM, provide significant insights which need to be confirmed with randomized, controlled clinical trials, which are the highest level of clinical evidence in medicine," Dr Matthew said.

NEJM includes a report of a pooled analysis of patient-level data up to five years from 14 randomized controlled trials comparing the Cypher stent to bare metal stents in more than 4,900 patients. This is the most comprehensive study conducted to date; it provides the most in depth information about the safety and efficacy of the product.

It encompasses randomized controlled studies of on-label use, as well as dedicated studies of broader patient populations not within the approved labeling. Currently, off-label use would include those with diabetes, in-stent restenosis, chronic total occlusions, acute myocardial infarction and unselected patient populations.

In this meta-analysis, there was no significant statistical difference on the risk of event thrombosis between Cypher Stent and bare metal stents over four years. However, if patients who had intervening repeat revascularizations are included in the analysis, as they are when applying definitions of stent thrombosis developed by the Academic research Consortium, there were eight late thrombosis in patients treated with the Cypher Stent and six in those treated with bare metals stents. In addition, the overall risk of fatality and myocardial infarction were not significantly different between the two treatment arms.

In the pooled analysis, the use of the Cypher Stent in diabetics was not associated with a higher risk of death or myocardial infarction. Data from earlier clinical trials and registries of the safety of DES in diabetics were inconsistent. Therefore the use of the Cypher Stent and other DES in diabetics is not presently within approved labeling for these devices.

Dr Mathew noted that the total body of clinical evidence, particularly with randomized clinical trials, did not suggest an excess mortality with Cypher Stent in either the total population or diabetics.