NEW YORK (Reuters Health) – Three cardiologists from China say intracoronary administration of a glycoprotein IIb/IIIa receptor inhibitor (GPI) “can be recommended as a preferred regimen” during primary percutaneous coronary intervention (pPCI) in patients with ST-segment elevation myocardial infarction (STEMI).
Their belief stems from a meta-analysis they conducted of all currently available randomized controlled trials comparing intracoronary (IC) and intravenous (IV) administration of GPIs in this patient population.
GPIs are now widely used during pPCI in STEMI patients, yet the best route of administration (IC or IV) remains the subject of much debate. The studies and meta-analyses that have looked at this issue have left clinicians with a mixed bag of results and no clear answers.
For example, the CICERO trial, published in 2010, found mixed results for IC versus IV abciximab and the EASY-MI trial published the same year didn’t find an advantage of IC administration.
A meta-analysis published in 2010 from Dr. Peter Riis Hansen, from Gentofte University Hospital, Hellerup, Denmark, and colleagues suggested favorable effects of IC over IV abciximab in patients with acute coronary syndromes. But the reliability of the analysis was limited due to the heterogeneity of the studies.
In 2011, Dr. Yuichi J. Shimada of Beth Israel Medical Center in New York City and colleagues did a meta-analysis of four relatively small but high-quality randomized controlled studies. They concluded that IC abciximab may have advantages over IV administration, particularly in higher-risk patients.
When Dr. Shimada’s meta-analysis was published, he told Reuters Health, “We would recommend (considering) the direct injection method for heart attack patients with high-risk features.” But Dr. Hansen said he believes the IV method “should remain the standard of care.”
The latest meta-analysis, online January 16 in the American Journal of Cardiology, is the work of Dr. Yongshi Wang and Dr. Xianhong Shu, from the Shanghai Institute of Cardiovascular Diseases and Dr. Boting Wu of Fudan University, also in Shanghai.
It included the CICERO and EASY-MI trials and the six other randomized controlled trials that have been published to date.
During pPCI for STEMI, the IC route was used in 686 patients and the IV route in 660. IC boluses of GPIs were given just after restoration of anterograde flow to allow high GPI concentration in the target region. IV GPIs were administered before or during PCI.
According to the Shanghai group, final TIMI grade 3 flow was achieved in 87% in the IC group and 82% in the IV group.
Patients benefited more from IC bolus in terms of procedural success rate (odds ratio 1.46 for TIMI grade 3 flow; p<0.05), they note. Myocardial reperfusion grade 2 or 3 was also more likely in the IC arm (OR 1.78; p<0.001).
An IC bolus of GPI was more effective in reducing mortality (OR 0.44; p<0.05), target vessel revascularization (OR 0.53; p<0.05), and the composite end point of major adverse cardiac events (OR 0.48; p<0.05) at 30-day follow-up. There were no significant differences between IC and IV administration in terms of major or minor bleeding (OR 1.14 and 0.86, respectively).
The authors say the major advantage of IC administration of antithrombotic agents during PCI is achieving a higher local concentration, resulting in a higher procedural success rate, demonstrated by TIMI grade 3 flow, and better tissue-level reperfusion status, indicated by a myocardial blush grade or a TIMI myocardial perfusion grade of 2 or 3 compared to IV delivery.
They note that while no statistical heterogeneity was evident in the analysis, “the dosing regimen at the operators’ discretion resulted in heterogeneity between protocols.”
The researchers are hopeful that further studies — including Abciximab Intracoronary Versus Intravenously Drug Application in ST-Elevation Myocardial Infarction (AIDA STEMI), Intracoronary Abciximab With ClearWay Catheter (IC ClearLy), and INFUSE–Anterior Myocardial Infarction (INFUSE-AMI) — will provide more evidence on the optimal dosing strategy of GPIs in patients with STEMI.
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