The Clinical Significance of HbA1c in Operable Chronic Thromboembolic Pulmonary Hypertension

Background Glycosylated hemoglobin A1c (HbA1c) has been proposed as an independent predictor of long-term prognosis in pulmonary arterial hypertension. However, the clinical relevance of HbA1c in patients with operable chronic thromboembolic pulmonary hypertension (CTEPH) remains unknown. The aim of the present study was to investigate the clinical significance of HbA1c as a biomarker in CTEPH. Methods Prospectively, 102 patients underwent pulmonary endarterectomy (PEA) in our national referral center between March 2013 and March 2014, of which after exclusion 45 patients were analyzed. HbA1c- levels, hemodynamic and exercise parameters were analyzed prior and one-year post-PEA. Results 45 patients (BMI: 27.3 +/- 6.0 kg/m(2); age: 62.7 +/- 12.3 years) with a mean pulmonary arterial pressure (mPAP) of 43.6 +/- 9.4 mmHg, a pulmonary vascular resistance (PVR) of 712.1 +/- 520.4 dyn*s/cm(5), a cardiac index (CI) of 2.4 +/- 0.5 l/min/m(2) and a mean HbA1c-level of 39.8 +/- 5.6 mmol/mol were included. One-year post-PEA pulmonary hemodynamic and functional status significantly improved in our cohort. Baseline HbA1c-levels were significantly associated with CI, right atrial pressure, peak oxygen uptake and the change of 6-minute walking distance using linear regression analysis. However, using logistic regression analysis baseline HbA1c-levels were not significantly associated with residual post-PEA PH. Conclusions This is the first prospective study to describe an association of HbA1c-levels with pulmonary hemodynamics and exercise capacity in operable CTEPH patients. Our preliminary results indicate that in these patients impaired glucose metabolism as assessed by HbA1c is of clinical significance. However, HbA1c failed as a predictor of the hemodynamic outcome one-year post-PEA.