Preoperative serum LOXL2 levels are elevated in patients with pulmonary hypertension undergoing mitral valve surgery in a prospective observational cohort study.

Abstract

Lysyl oxidase-like 2 (LOXL2) is associated with vascular remodeling associated in pulmonary hypertension (PH). This study evaluates the potential of serum LOXL2 levels as a clinical biomarker. We enrolled 158 patients undergoing mitral valve surgery. Using echocardiographic right ventricular systolic pressures (RVSPs), patients were stratified into those with and without PH preoperative, postoperative, and postdischarge. Healthy volunteers served as a nonsurgical control. Serum LOXL2 concentrations preincision were compared with RVSPs using simple regression and their relationship to PH using one-way ANOVA with Tukey's posttest. Serum LOXL2 concentrations were significantly higher in patients with PH compared with patients without PH (2,718 ± 5,187 pg/mL vs. 640 ± 1,367 g/mL; P = 0.0009) and compared with healthy volunteers (283 ± 615 pg/mL; P = 0.04). There was a positive correlation between RVSPs and serum LOXL2 concentrations (P = 0.02, r² = 0.08). Serum LOXL2 levels positively correlated with intraoperative indices of pulmonary compliance, suggesting that PH in this cohort may primarily represent postcapillary PH. Patients with PH postprocedure (and before discharge) had greater preprocedure serum LOXL2 levels compared with patients without PH (4,348 ± 8,498 pg/mL vs. 1,281 ± 2,329 pg/mL, P = 0.006), as did patients assessed after discharge (1,359 ± 2,693 pg/mL vs. 4,195 ± 6,568 pg/mL, P = 0.009). Patients with persistent PH or new PH had elevated presurgical LOXL2 levels compared with those without PH at both timepoints (4,301 ± 7,717 pg/mL vs. 556.6 ± 835.8 pg/mL, P = 0.02; 2,902 ± 5,255 pg/mL vs. 556.6 ± 835.8 pg/mL, P = 0.03). Serum LOXL2 is elevated in patients with PH. LOXL2 is a potential PH biomarker in patients undergoing mitral valve surgery. This could have implications for follow-up care.NEW & NOTEWORTHY Serum LOXL2 levels are elevated in patients with PH undergoing mitral valve surgery, and they do correlate with disease severity and persistence, suggesting that LOXL2 plays a role in human PH and holds potential as an important biomarker for PH.