A study presented at the 32nd Society for Cardiovascular Angiography and Interventions (SCAI) Scientific Sessions (Las Vegas, Nevada, May 6-9, 2009), concludes that the one year risk of cardiovascular events is increased more than 50 % in patients taking a proton-pump inhibitor (PPI) in addition to clopidogrel, following stenting, as compared with patients not taking a PPI.
Commenting on the results, ESC spokesperson Professor William Wijns, from Belgium, who is President of the European Association of Percutaneous Cardiovascular Interventions, said :
“ This retrospective analysis of a large medical claims database suffers from all limitations of retrospective, registry-driven analyses. Foremost, it cannot be excluded that the increased event rate stems from the worse underlying condition of the patients in whom PPI was deemed necessary. Furthermore, the robustness of these findings depends on the accuracy of the encoding process, as well as the consistency of the event definition. “
He added that the present study calls for a proper appraisal of the issue. “It is not known whether the effect was primarily seen in patients who are less responsive to the drug, particularly since no biochemical assays of the antiplatelet efficacy were provided. MACE included cerebrovascular events (MACCE) and were only reported as a cumulative rate. It is possible that the drug interference merely affects the neuroprotective action of clopidogrel. But again specific stent thrombosis rates were not available. “
ESC Spokesperson Professor Freek Verheugt, from the Netherlands, added, that there have been previous reports concerning the clinical interaction of PPI and clopidogrel, but that the effect could not be reproduced in the huge TRITON trial. “ We have seen these so-called clinical interactions before, like the one between clopidogrel and statins, which could not be confirmed with larger data.” Only a prospective randomized trial of PPI versus placebo in patients on clopidogrel, he added, would give the final answer.
Dr Steen D. Kristensen, from Denmark, spokesperson and Vice-president for the ESC, adds: ‘Nevertheless we should be careful not to use proton pump inhibitors uncritically in patients with unclear gastric symptoms. In patients with evident gastric ulcers I would consider using alternative gastroprotective drugs. It needs to be remembered that in patients with coronary stents, inhibition of platelets is crucial so it's very important not to stop dual anti-platelet therapy.”