In vitro effects of coronary angiography: unknown clinical implications

In coronary angiography, contrast media (a non-physiologic solution) comes in direct contact with coronary arteries endothelium, and a foreign body, the polyurethane and polyethylene material of the cardiac catheter, oscillates on endothelium. The endothelium differential responses to various mechanical stimuli include: intracellular calcium influx, release of endothelin and substance P, vascular free radical generation, enhancement of platelet-derived growth factor-A (PDGF-A) mRNA, PDGF-A, upregulation of intracellular adhesion molecule-1 mRNA and protein, enhanced lymphocyte adhesion, upregulation of endothelin mRNA and protein, and stimulation of low density lipoprotein metabolism, increase of interleukin 6 and C-reactive protein. Contrast media effects include: change of endothelial cell morphology and exposure of extracellular matrix, increase adhesiveness to leukocytes, decrease production of nitrous oxide, vasoconstriction with some agents, factor XII activation, increase in the release of kallikrein, bradykinin, histamine, serotonin, and leukotriene B4, and variable effects of platelet activation and aggregation. Passing the cardiac catheters through vascular tree was also noticed to be associated with subclinical embolization of aortic debris. Some clinical studies showed that coronary angiography resulted in elevation of serum inflammatory markers, specifically in patients with elevated baseline levels of these markers. Clinical significance of pro-inflammatory effects of coronary angiography, and its long term consequences, are not studied. Further studies utilizing non-invasive coronary imaging techniques is needed to elucidate such effects.