Long-Term Prognostic Value of Lipoprotein(a) in Symptomatic Patients With Nonobstructive Coronary Artery Disease

Our study aimed to evaluate the association of lipoprotein(a) [Lp(a)] and prognosis in patients with nonobstructive coronary artery disease (CAD). A total of 4,254 symptomatic patients with suspected CAD referred for coronary angiography were analyzed and 451 patients (250 women, average age 58 ± 9 years) with nonobstructive CAD (defined as no angiographic stenosis ≥50% in any major epicardial artery) were finally included in our cohort. Subjects were categorized into tertile groups according to Lp(a) levels on admission. The primary end point was major adverse cardiovascular events (MACEs), defined as cardiac death and incident acute coronary syndrome. Over a mean follow-up of 32 ± 22 months, 37 (8%) MACE (15 cases of cardiac death and 22 cases of acute coronary syndrome) occurred. Kaplan-Meier analysis revealed that elevated Lp(a) level was associated with worse prognosis (p = 0.001). After Cox multivariate adjustment for other clinical confounders, an elevated Lp(a) level remained an independent predictor of MACE either as a continuous variable (hazard ratio 1.031, 95% confidence interval 1.019 to 1.043, p <0.001) or as a categorical variable (hazard ratio 3.155, 95% confidence interval 1.599 to 6.229, p = 0.001). Furthermore, addition of Lp(a) to established coronary risk factors significantly improved the predictive value of reference models for MACE. In conclusion, an elevated Lp(a) level is independently associated with worse prognosis and may provide useful risk stratification in symptomatic patients with nonobstructive CAD.