EPO Augments Effect of Novel Stent in STEMI Patients

PARIS, France—Administering a single dose of erythropoietin (EPO) to ST-segment elevation myocardial infarction (STEMI) patients treated with a novel stent designed to capture circulating endothelial progenitor cells (EPCs) reduces neointimal proliferation and the need for repeat procedures. The promising but early results were announced Thursday, May 19 at EuroPCR 2011.

Harry Suryapranata, MD, PhD, of De Weezenlanden Hospital (Zwolle, the Netherlands), presented findings from the Zwolle substudy of the HEBE-III trial, which is examining the effects of EPO vs. standard treatment on LVEF in STEMI patients. The substudy specifically looked at 196 STEMI patients enrolled in the trial who underwent primary PCI with the Genous EPC Capture stent (OrbusNeich, Wanchai, Hong Kong) and were randomized to receive standard therapy plus a single bolus of EPO (60,000 IU) or placebo. Baseline characteristics were well balanced between the 2 groups.

“The EPC Capture stent was developed to promote rapid stent re-endothelialization by capturing the patient's own EPCs. It has also been shown that the higher the circulating EPC levels, the lower the late loss,” Dr. Suryapranata said, noting that the number of EPCs increases in the STEMI setting. EPO, meanwhile, “stimulates mobilization of EPCs from bone marrow, and therefore it is interesting to study the . . . Genous stent in patients receiving a single bolus of EPO.”

Significant Findings From Small Cohort

In the 80 patients who underwent quantitative coronary angiography (QCA) at 9 months, the study's primary endpoint of late loss was lower with the addition of EPO. Minimum lumen diameter and percent diameter stenosis showed positive trends (table 1).

Table 1. QCA Results at 9 Months

 

EPO
(n = 39)

Placebo
(n = 41)

P Value

Late Loss, mm

0.43

0.79

0.004

Minimum Lumen Diameter, mm

1.80

1.65

NS

Percent Diameter Stenosis

31.6%

40.5%

NS


Clinical follow-up in the entire cohort at 1 year yielded no deaths and 1 repeat MI with EPO treatment. Moreover, the incidence of repeat PCI was higher after placebo than after EPO at 18% vs. 7%, respectively (P = 0.013).

Although the results indicate the safety and efficacy of EPO in combination with the Genous stent, Dr. Suryapranata said, the study is small, from a single center, and provides limited angiographic follow-up. Moreover, the researchers did not obtain data on EPC levels.

Case of the Missing EPCs

Session co-chairs Ran Kornowski, MD, of the Rabin Medical Center (Petach Tikva, Israel), and Mitchell W. Krucoff, MD, of the Duke Clinical Research Institute (Durham, NC), expressed reservations about the study.

The key question, Dr. Krucoff commented, is how to tease out which factor in the study exerted influence on outcomes in STEMI patients: the Genous stent, the EPO bolus, or both.

“I think you have to look at this as a kind of proof of concept study, nothing more or less than that. I don't think we should give EPO to every STEMI patient,” Dr. Suryapranata replied. “What we don't know is the maturity of these cells. That is a big issue to prove.”

Maximizing EPC counts is a crucial element, he noted, and follow-up studies should measure circulating EPC levels at baseline and follow-up.

“Why didn't you check it?” Dr. Kornowski asked. “This was the fundamental [basis] of your scientific hypothesis. Let's assume that the EPC counts are equal between the 2 groups. What's the conclusion then?”

Without directly answering the question about study methodology, Dr. Suryapranata replied that if there was no difference in EPC levels, then the results could be attributed to the Genous stent.

 


Source:
Suryapranata H. HEBE-III randomised trial: A Zwolle sub-study with the Genous stent. Presented at: EuroPCR; May 19, 2011; Paris, France.

 

 

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Disclosures
  • Dr. Suryapranata reported having research contracts with OrbusNeich.

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