(FORTUNE Magazine) – Move over, cholesterol. The latest heart-attack culprit is C-reactive protein (CRP). CRP, which is produced when arteries are inflamed, was nailed in a groundbreaking November New England Journal of Medicine study as an even better predictor of heart disease than LDL cholesterol (FORTUNE wrote about CRP back in June; see "Is This Artery About to Blow?" on the fortune.com archive). But which companies will cash in on the 25 million Americans with elevated CRP?

First may be the makers of cholesterol drugs, or "statins," such as Pfizer's Lipitor, Merck's Zocor, and AstraZeneca's Crestor (currently awaiting FDA approval). Studies have shown that statins do lower CRP (probably by reducing plaque in the arteries and hence inflammation), but not enough testing has been done to know how effective they really are. Completing expensive clinical trials and getting FDA approval to treat CRP with statins could take five years. That gives the deepest-pocketed drugmakers a huge advantage, says Herman Saftlas, an analyst at Standard & Poor's. Other potential CRP treatments are anti-inflammatory drugs such as Merck's Vioxx and Pfizer's Celebrex. But those drugs can increase the risk of heart attack, so it's unclear whether they are appropriate remedies.

Finally, testmakers such as Quest, Dade Behring, and Beckman will benefit as millions of Americans rush to their doctors for a CRP screen. Meanwhile Dr. Paul Ridker, author of the CRP study, says there's one bestselling drug with major CRP-lowering potential: good old aspirin. --Noshua Watson