Decreased circulating lipoprotein-associated phospholipase A2 levels are associated with coronary plaque regression in patients with acute coronary syndrome.

OBJECTIVE: Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a vascular-specific inflammatory enzyme, of which increases are associated with cardiovascular events. However, the relationship between circulating Lp-PLA2 levels and coronary plaque volume has not been clarified in patients with acute coronary syndrome (ACS).

METHODS: We studied 40 patients with ACS (age, 61.4 ± 8.0 years; male, 87.5%; statin use, 45.0%) who had undergone successful percutaneous coronary intervention (PCI). Plaque volume (PV) in non-culprit sites of PCI lesions was precisely determined using grayscale intravascular ultrasound (IVUS) at onset and at six months later. We then analyzed associations among PV, lipid profiles and Lp-PLA2 levels.

RESULTS: Circulating Lp-PLA2 levels and PV significantly decreased between baseline and six months of follow-up (458.6 ± 166.7 IU/L vs. 378.4 ± 158.5 IU/L, p < 0.001 and 82.2 ± 34.8mm(3) vs. 77.3 ± 33.1mm(3), p < 0.001, respectively). The % change in PV positively and significantly correlated with % change in LDL-C and in the LDL-C/HDL-C ratio (r = 0.444, p = 0.004 and r = 0.462, p = 0.003, respectively). Furthermore, % changes in Lp-PLA2 and in PV correlated even more closely (r = 0.496, p = 0.001). The absolute change in PV also significantly correlated with the change in Lp-PLA2 levels (r = 0.404, p = 0.009).

CONCLUSIONS: Circulating Lp-PLA2 levels are associated with changes in coronary plaque determined by IVUS in patients with ACS.