MUNICH, Germany — If a diabetic patient does not mind the high likelihood of going back on the table for a repeat percutaneous intervention (PCI), then a drug-eluting stent (DES) is, "if not a good alternative, then at least okay."
This conclusion to a debate focused on PCI for diabetic patients, delivered by Marko Noc, MD, an interventional cardiologist at the University Medical Center Ljubljana in Slovenia, was half-hearted and inconclusive, but typical of all discussion centered on DES during the annual congress of the European Society of Cardiology (ESC; Sophia Antipolis, France) held here last week.
It also is the state-of-the-art guidance for cardiologists treating diabetics, despite industry promotions to the contrary, and it will be many years before there is sufficient data to say otherwise, according to speakers taking positions on both sides of the highly controversial use of DES to treat coronary complications for diabetics.
Diabetes in Europe, as elsewhere in the world, is approaching epidemic proportions, with an estimated 4% of the European population affected, or roughly 10 million diabetics.
That represents, potentially, a lot of stents to be sold as 100% of Europe's diabetic population is destined to sooner or later undergo some form of cardiovascular intervention.
During the debate, independent of industry sponsorship, the consensus was that it is impossible to form a consensus.
Both William Wijns, MD, president of the European Association for Percutaneous Cardiovascular Interventions (EAPCI), who took up the position against DES, and Sigmund Silber, MD, from Mueller Hospital (Munich), who in his effort to defend DES found himself constrained to a "balanced viewpoint," ended up agreeing that there is no study and no evidence with a clear endpoint that allows for any evidence-based practice guideline.
Yet there seemed to be no end of clinical trials testing DES with diabetics.
At its booth on the exhibit floor, Boston Scientific (Natick, Massachusetts) boldly promoted a special logo claiming CE-mark approval for diabetes for the Taxus Libert stent.
The CE mark is strictly an approval of safety for an implantable medical device, and unlike FDA approval in the United States, there is not a requirement to demonstrate efficacy.
While strictly correct, according to a European expert on regulatory affairs, the promotion by Boston Scientific is an aggressive extrapolation of CE-mark approval for a suggested use included in the product design documentation that was submitted by the company.
"No, it is not mandatory," explained a Boston Scientific spokesman at the booth, "it is an update to the instructions for use, which is normal."
"What Dr. Wijns is saying is right, and we do not disagree" he said. "We do not have a diabetic study that is dedicated and sufficiently powered with a clinical endpoint comparing the technologies. But what we are saying is that there are multiple trials in which the diabetic cohort is sufficient and as such gives what we believe is sufficient clinical proof for recommending use of DES in diabetic patients."
He said that Boston Scientific believes the drug paclitaxel, which is coating the Taxus stent, makes the difference compared to the sirolimus-eluting Cypher stent from Cordis (Warren, New Jersey), "and we are happy to show here on the stand our evidence that there is a big difference in results for Taxus compared to Cypher."
Back in the scientific sessions, the CARDia clinical trial (Coronary Artery Revascularization in Diabetes Trial) was presented, with one-year results for PCI among diabetic patients with multi-vessel coronary disease compared to coronary artery bypass graph (CABG) procedures.
With 510 patients randomized between the two procedures, CARDia is the largest trial to date specifically comparing the technologies. Among the 256 patients undergoing PCI, a subgroup of 179 PCI patients received Cypher stents rather than bare-metal stents.
Presenting the results, Akhil Kapur from the London Chest Hospital, said the non-inferiority parameters were not met in the study due to the trial being insufficiently powered and that recruitment was only 85% of the design requirements.
This study confirmed that except for equal rates of death and a slightly higher incidence of non-fatal myocardial infarction (MI), drug-eluting stents came out favorable for a lower number of strokes experienced within the first year but the number was dramatically higher for repeat revascularization at 9.9% compared to 2% for CABG.
Kapur's conclusion was consistent, nonetheless, with other industry-sponsored clinical studies, saying "PCI may now be considered a reasonable strategy in diabetic patients."
In other words, details aside, DES is viable.
Not so, argued Wijns in a presentation that bordered on passionate within the context of a cardiology conference.
"DES should be avoided in diabetics," he said.
With 30 randomized trials being circulated, Wijns said there is still no reliable data with the majority of studies, including only subgroups of patients with diabetes and not dedicated to patients with diabetes in particular.
He declined to comment on the CARDia trial, as it was to be presented after the "DES in diabetics" debate.
"CABG has been associated with mortality benefit for patients with multi-vessel disease, while no such effect was observed with bare-metal stenting, nor is to be expected from stenting using DES," he said.
The key is recognizing diabetes as an equivalent to cardiovascular disease, said Wijns.
"The very presence of diabetes should give pause and given the complexity it needs to be recognized that it is going to take more than a 16 mm stent to improve the dismal outcomes for these patients," he said.
Defending DES, Silber said, "It will be years until we get results, and yet we need to make decisions today. My conclusion is DES should be used with the major factor being whether the patient can tolerate the risk of a repeat revascularization and where the expected compliance with platelet drug therapy is expected to be high."