Background: Adhesion molecules on arterial endothelium have been implicated in spontaneous atherosclerosis and transplant coronary artery disease (CAD). We studied whether elevated serum-soluble intercellular adhesion molecule-1 (sICAM-1) during the immediate posttransplant period was a risk factor for CAD, posttransplant ischemic events, or cardiac graft failure.
Methods and results: We initially studied serum sICAM-1 in a subset of 16 cardiac allograft recipients (5.5+/-0.7 samples per patient) to determine a cutoff point that best correlated with presence of arterial and arteriolar endothelial ICAM-1 in matching endomyocardial biopsies. The cutoff value was 308 ng/mL. Subsequently, we prospectively evaluated serum sICAM-1 in serial samples (5.3+/-0.1 per patient) obtained during the first 3 months after transplantation in a validation subset of 130 recipients and correlated early sICAM-1 levels with long-term outcome. Serum sICAM-1 >308 ng/mL correlated significantly with ICAM-1 on arterial and arteriolar endothelium (P:=0.02). Cardiac allograft recipients with serum sICAM-1 >308 ng/mL had 2.67 (95% CI, 1.28 to 5.59, P:=0.009) times greater risk of CAD and 3.63 (95% CI, 1.05 to 12.5, P:=0.04) times greater risk of graft failure. Recipients with sICAM-1 >308 ng/mL also developed more severe CAD (P:=0.009) and more ischemic events (P:=0.03) after transplantation.
Conclusions: Serum sICAM-1 levels can be used to noninvasively assess risk of transplant CAD, posttransplant ischemic events, and cardiac graft failure.