Immature Surfactant Protein Type-B Associates With Graft Patency in Patients Undergoing Coronary Artery Bypass Grafting

Abstract

Background

Coronary artery bypass graft (CABG) surgery is performed in patients with complex multivessel coronary artery disease, but long-term graft occlusion remains a major limitation. The immature surfactant protein type-B (proSP-B) has emerged as a predictor of adverse cardiovascular outcomes.

Objectives

The purpose of this study was to examine the relationship between preoperative plasma proSP-B and graft occlusion 18 months post-CABG. The aims were to evaluate whether elevated proSP-B could predict graft occlusion and to assess its predictive value within a multivariable model for long-term graft patency.

Methods

We evaluated proSP-B in relation to graft occlusion in 40 patients with occluded grafts (cases) and 130 patients without occlusions (noncases), with 18-month graft patency assessed by coronary computed tomography angiography and/or invasive angiography. Logistic regression assessed the association between proSP-B and graft occlusion. Predictive performance was evaluated using receiver-operating characteristic curves and category-free net reclassification improvement.

Results

Preoperative proSP-B was significantly elevated in cases compared to noncases (24.0 [IQR: 19.8-31.0] AU vs 19.4 [IQR: 14.0-25.0] AU; P = 0.002). In a multivariable analysis, proSP-B associated with increased risk of graft occlusion, even after adjusting for factors like D-dimer, left ventricular ejection fraction, and extracorporeal circulation time. Including proSP-B in a reference model improved the area under the curve from 0.7204 to 0.7733, significantly enhancing patient classification (net reclassification improvement = 0.43; SE = 0.18; P = 0.02).

Conclusions

Elevated preoperative proSP-B is independently associated with 18-month graft occlusion following CABG. Including proSP-B improves existing predictive models, supporting its role as a novel biomarker for risk stratification in surgical revascularization.