The cardiovascular risk spike following surgery may stem from a previously unrecognized mechanism: surgical trauma fundamentally rewires the body's cholesterol transport system, leaving arterial plaques vulnerable to rupture. This finding challenges the assumption that post-surgical heart problems result mainly from surgical stress on existing heart conditions.
Using atherosclerosis-prone mice undergoing controlled abdominal surgery, researchers discovered that surgical inflammation rapidly transforms HDL particles—the "good cholesterol" carriers—into dysfunctional versions. The inflammatory protein SAA1/2 replaces beneficial Apolipoprotein A1, crippling reverse cholesterol transport (RCT), the process that removes excess cholesterol from arterial walls. Within arterial plaques, foam cells accumulated toxic lipid droplets marked by PLIN2 protein expression, triggering cell death cascades that destabilize plaque structure. Remarkably, surgical stress selectively impaired macrophage-driven cholesterol removal while leaving vascular smooth muscle cell transport intact, revealing cell-type-specific vulnerabilities.
This mechanism extends beyond animal models—plasma from human surgery patients showed similarly impaired cholesterol efflux capacity postoperatively. The research represents a significant advance in understanding perioperative cardiovascular risk, moving beyond hemodynamic explanations to identify specific molecular pathways. Treatment with recombinant APOA1 partially restored cholesterol transport function and reduced plaque lipid burden in mice, suggesting therapeutic potential. However, the brief study timeframe and reliance on atherosclerosis-prone mouse models limit immediate clinical translation. The findings suggest that perioperative HDL dysfunction may be an underappreciated but modifiable risk factor for the 300,000 annual cardiovascular events following non-cardiac surgery.