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Thursday, March 3, 2005

Increase in WBCs Linked to Increased Muscle Damage and Higher Death Rate
By Julie McKeel

For heart attack patients treated with angioplasty and/or stenting, an increase in white blood cells (WBCs) and body temperature over the first few days after treatment has been linked to an increase in the amount of damage to the heart muscle. An increased death rate for these patients was noted as well, according to an analysis of patients combined from two related reperfusion trials. Reperfusion is the process of restoring the blood supply to tissue damaged by a heart attack.

Manesh Patel, MD

The study, reported in the March 1, 2005 issue of the American Journal of Cardiology, indicates that patients who develop a high temperature and increased WBCs the second day after treatment for a heart attack aren’t necessarily suffering from an infection. "It may mean, in fact, that there's a larger amount of necrosis [tissue death] and that these patients are at higher risk and should have aggressive therapy. If the artery's not open, they should have revascularization as soon as possible," lead author Dr Manesh Patel told theheart.org.

Patel and his colleagues studied WBC counts and temperature readings from patients in two phase-2 trials, components of the Complement and Reduction of Infarct Size after Angioplasty or Lytics (CARDINAL) program, that explored whether additional treatment with the anti-complement-C5 antibody pexelizumab could limit the amount of damaged tissue. Their analysis combined the 934 patients from the Complement Inhibition in Myocardial Infarction Treated with Thrombolytics (COMPLY) trial and the 960 patients from the Complement Inhibition in Myocardial Infarction Treated with Angioplasty (COMMA) trial.

"We showed that the baseline WBC count directly correlated with infarct [area of tissue death] size as measured by CKMB (creatine kinase-MB) area under the curve for the first 72 hours . . . and with adverse outcomes, including mortality and heart failure at 90 days," Patel told theheart.org.

The analysis also showed that the change in WBC counts from baseline to 24 hours directly related to the size of the area of tissue damage as well as with the rate of death. Regardless of baseline WBCs, patients with increased WBC count over the first 24 hours had a higher death rate than those with no change or a decrease in the counts. But increased baseline WBCs and temperature were not correlated with each other.

"The larger the area of damage, the higher the white blood cell count," Patel said. Elevated WBCs "might be just a marker if there are a lot of WBCs, there's a lot of necrosis or it might be related to [changes] in the coronaries and in the inflamed area around the necrosis that leads to worse outcomes."

Trials in the CARDINAL program were supported by Procter & Gamble Pharmaceuticals and by Alexion Pharmaceuticals.