MIAMI—There was no difference in myocardial damage or reperfusion injury with abciximab (ReoPro, Eli Lilly) delivered directly to the heart, called an intracoronary delivery, as compared with receiving the agent intravenously (IV) in STEMI patients, based on cardiac MR data from the AIDA STEMI MRI substudy.

These findings were presented Oct. 25 as a late-breaking clinical trial at the 2012 Transcatheter Cardiovascular Therapeutics (TCT) conference.

The previous AIDA STEMI trial was a randomized, open-label, multicenter trial in 2,065 patients presenting with STEMI comparing IC versus IV abciximab during PCI with subsequent 12-hour IV infusion. In AHA.11, lead investigator Holger Thiele, MD, co-director of the University of Leipzig-Heart Center in Germany, reported that the trial found that both methods yielded similar 90-day rates of all-cause mortality, recurrent heart attack or congestive heart failure.

Thiele said that cardiac MR enables investigation of mechanistic and pathophysiological effects of intracoronary plus intravenous abciximab application on myocardial damage and reperfusion injury. “This is the largest study using cardiac MR in STEMI patients,” he added.

For this cardiac MR substudy, the researchers enrolled 703 STEMI patients from the overall trial at eight study sites. Cardiac MR allows for a more sensitive investigation of the mechanistic and pathophysiological effects of STEMI therapies on myocardial damage and reperfusion injury.

The cardiac MR was completed within four days after the STEMI using a standardized protocol including edema imaging and late gadolinium enhancement. The researchers examined infarct size, myocardial salvage, microvascular obstruction and ventricular function to determine the potential benefits of IC compared to IV application of abciximab.

For the study, 394 patients were randomized to the intracoronary arm, and 401 to the IV group. Both groups received the standard 12 hours of infusion. There were no differences in the baseline patient characteristics of either group.

The amount of myocardium at risk and final infarct size did not differ significantly between the IC versus the IV abciximab groups, according to Thiele. Consequently, the myocardial salvage index was similar between the two groups. In further detailed analysis there were no differences in microvascular obstruction between both treatment groups.

“We were able to see that the infarct size was significantly smaller in those patients without major adverse coronary events [MACE],” he said. The myocardial salvage index and the left ventricular ejection fraction were significantly higher in those patients without MACE.

“The results of the AIDA STEMI CMR substudy therefore confirm the lack of difference in the combined endpoint of death, reinfarction or congestive heart failure of the AIDA STEMI trial,” Thiele concluded.

“This substudy nicely completes the overall trial because there was no difference in outcomes from the overall trial,” said study discussant Alice Jacobs, MD, of Boston Medical Center.

Study discussant Ajay J. Kirtane, MD, of New York-Presbyterian and Columbia University Medical Center, questioned the validity of cardiac MR as an endpoint. Thiele responded, “I think it’s a valid endpoint because we have shown through this large trial that it’s important to reduce the size of MI, among other important outcomes.” He also pointed to the INFUSE AMI trial as another example of its validity.

The trial was funded by Lilly Germany, the University of Leipzig-Heart Center and Clinical Trial Centre and the Federal Ministry of Education and Research in Germany.