For decades, cardiovascular prevention research has wrestled with a stubborn confound: patients in trials who say they're taking their medication often aren't, quietly undermining effect estimates. A rigorous sub-study of the PACMAN-AMI trial turns that concern on its head — at least within the controlled trial environment — and in doing so offers unusually precise data linking verified statin exposure to coronary plaque biology.
Using liquid chromatography tandem mass spectrometry — the same technology used in toxicology and doping controls — investigators objectively measured rosuvastatin or atorvastatin blood concentrations in 255 post-AMI patients at 4 and 52 weeks. Non-adherence, defined as undetectable drug concentrations, was exceptionally rare: only 1.2% at 4 weeks and 2.0% at 52 weeks. Among confirmed adherent patients, the LDL-C reduction at one year averaged −2.73 mmol/L versus a negligible +0.07 mmol/L in the handful of non-adherent individuals. More compellingly, adherent patients showed meaningful regression in percent atheroma volume (−1.54% vs. −0.15% by intravascular ultrasound), substantial reduction in lipid core burden index measured by near-infrared spectroscopy (−60.6 vs. 0.0), and greater fibrous cap thickening on optical coherence tomography — a structural marker of plaque stabilization.
The findings carry two distinct layers of importance. First, they validate PACMAN-AMI's primary imaging outcomes by confirming that the biological effects observed were indeed driven by actual drug exposure rather than self-reported adherence. Second, the multi-modality intracoronary imaging approach — simultaneously capturing plaque volume, lipid content, and cap morphology — provides a richer mechanistic portrait than LDL reduction alone. The near-perfect trial adherence (>98%) is encouraging but limits generalizability: real-world statin adherence post-AMI falls to roughly 50–60% within two years in population studies, meaning the plaque benefits documented here represent a best-case biological ceiling most patients never reach. The tiny non-adherent group also precludes statistical inference, making the between-group comparisons descriptive rather than confirmatory. Still, the methodology — direct bioanalytic verification paired with imaging endpoints — sets a useful standard for future adherence-sensitive cardiovascular trials.