Abstract 3634: Precapillary Component of Pulmonary Hypertension in Heart Failure is Linked to Insulin Resistance
Introduction: Some, but not all patients with heart failure (HF) develop precapillary pulmonary hypertension (PH) due to unidentified mechanisms. Based on experimental data, we hypothesized that insulin resistance might be involved in development of precapillary PH in HF.
Methods: 24 patients with HF and high pulmonary vascular resistance (hPVR, ≥2.5 wu) and 22 HF patients with low PVR of similar age, gender, medication, body size, diabetes prevalence and HF severity (52±12 years, 54% ischemic, DM in 35%, NYHA 2.9±0.7, EF 23±4%), underwent right heart cath. Right atrial (RA) blood was obtained to measure fasting insulin, glucose and free fatty acids (FFA). Insulin resistance was estimated by HOMA index. Pulmonary artery catheter samples before and during wedging were used to calculate transpulmonary insulin extraction.
Results: hPVR had similar systemic resistance, cardiac output (3.7 vs 4.3 l/min), RA pressure (9 vs 6 mmHg) and BNP (589 vs 723 pg/ml), but higher PVR (5.5 vs. 1.7 wu), transpulmonary gradient (TPG, 19 vs 7 mmHg, both p<0.001) and PA wedge pressure (26 vs 16 mmHg, p=0.001) than low-PVR. hPVR subjects had twice higher insulinemia (20.1 vs 10.2 μIU/ml, p=0.01) and higher HOMA index (6.8 vs 2.9, p=0.01), but similar glucose (7.0 vs 6.7 mmol/l) and FFA (0.8 vs 1.0 mmol/l) in RA. Insulinemia and HOMA index correlated with TPG (r=0.51 and 0.45, p≤0.003) and PVR (r=0.47 and 0.39, p≤0.001). Transpulmonary insulin extraction was similar in both groups (p=0.7), not related to PVR (r=0.06), suggesting indirect insulin effect.
Conclusions: Impaired whole body insulin sensitivity and hyperinsulin-emia are closely linked to precapillary component of PH in patients with heart failure.