Increases in serum unbound free fatty acid levels following coronary angioplasty

Serum unbound free fatty acid levels (FFA_u) were measured in patients undergoing percutaneous transluminal coronary angioplasty (PTCA) using the fluorescent probe acrylodan intestinal fatty acid binding protein (ADIFAB). These are the first measurements of FFA_u under nonphysiologic conditions. In these studies, FFA_u levels were determined in 22 patients 5 minutes before and 30 minutes after the procedure. Post-PTCA FFA_u levels were higher than pre-PTCA levels in all patients. The average post-PTCA level for all patients was 103 nM, about 14-fold higher than the 7.5 nM value observed in healthy subjects. Although all patients exhibited elevated FFA_u levels after PTCA, ischemic ST-segment changes were observed in only 11 of these patients. The average post-PTCA FFA_u levels for patients with significant ST-segment changes (123 nM) were significantly higher than those in patients who did not exhibit such changes (47 nM). Average FFA_u (22 nM) levels before the procedure were elevated in the patient population relative to healthy subjects and these values correlated positively with post-PTCA levels. These results suggest that increased serum FFA_u levels reflect angioplasty-induced ischemia and that FFA_u levels may provide a more sensitive measure of ischemia than electrocardiographic measurements. Moreover, because 30% of these patients had post-PTCA FFA_u concentrations exceeding those found to alter in vitro cell function, the increased serum FFA_u levels that accompany ischemia may be deleterious for myocardial function.