P3104Complementary impact of glycated haemoglobin and B-natriuretic peptide on cardiopulmonary exercise capacity in patients with ischemic heart disease

Abstract

Abstract Background Glycemic control, even in non-diabetes mellitus (DM) patients, has been associated with ventilation pump inefficiency leading to an impaired aerobic capacity. Brain natriuretic peptide (BNP) levels have also been correlated with exercise capacity, particularly in patients with heart failure. Purpose Assess the complementary impact of glycated haemoglobin (HbA1c) and BNP levels on cardiopulmonary exercise capacity in patients with ischemic heart disease (IHD). Methods Retrospecive cohort of 91 consecutive patients (57±10 years, 90% men; 29% type 2 DM) who underwent a cardiopulmonary exercise testing (CPX) at the beginning of an standard phase-II cardiac rehabilitation program, 2–3 months after an acute coronary syndrome. Results HbA1c and BNP levels correlated with peak oxygen uptake (VO2), anaerobic threshold (AT) and pulse O2 trajectory (Table). HbA1c correlated with ventilation CPX parameters (Table) and independently predicted minute ventilation (VE) and tidal volume (VT), regardless of age, waist circumference and β-blocker therapy. BNP levels correlated with echocardiographic (LVEF, left atrium size and pulmonary artery systolic pressure) and ventilation-perfusion (V/Q) mismatch parameters (Table), and independently predicted VE/VCO2-slope (P=0.037) regardless of age, echocardiographic parameters and β-blocker therapy. Patients were divided into three groups according to HbA1c levels above or below the DM diagnosis cut-off point (6.5%) and median value of BNP levels (44.6 pg/mL). VO2 and AT significantly decreased with elevated HbA1c and/or BNP levels (Figure). CPX parameters HbA1c (%) BNP (pg/mL) r P value r P value Peak VO2 (mL/min/kg) −0.421 <0.001 −0.295 0.005 VO2 at AT (mL/min/kg) −0.352 0.001 −0.271 0.009 O2 pulse trajectory (mL/beat) −0.345 0.001 −0.235 0.025 Minute ventilation (VE) (L/min)* −0.377 <0.001 – NS Tidal volume (VT) (L)* −0.348 0.001 – NS VE/VCO2-slope – NS 0.375 <0.001 PETCO2 at AT (mmHg) – NS −0.315 0.002 HR/VO2-slope – NS 0.307 0.003 *At peak exercise. NS: Non-significant. Conclusions HbA1c and BNP levels were associated with a reduced cardiopulmonary capacity in IHD patients, mediated by a ventilation impairment and a ventilation-perfusion mismatching, respectively. HbA1c and BNP are independent and additive predictors of cardiopulmonary capacity.