Comparison between arterial and venous sampling of circulating hormones, substrates and peptides in severe obesity

PURPOSE: Severely obese patients are being encountered more frequently in clinical practice. Factors implicated in the relationship between obesity and cardiovascular disease may be measured from a blood sample obtained through arterial access in a cardiology setting, such as during cardiac catheterization or heart surgery. The comparability of a given sample site (arterial vs. venous) with regards to blood parameters is yet to be established. METHODS: Fifteen severely obese patients undergoing bariatric surgery were recruited. Fasting blood samples were collected simultaneously from the radial artery (A) and the superior vena cava (V), both representing general circulating levels, after anesthesia but before the surgical procedure. Blood samples were analysed for glucose, insulin, non-esterified fatty acids (NEFA), leptin, adiponectin, total ghrelin, high sensitive C-reactive protein (hs-CRP) and amino-terminal pro-brain natriuretic peptide (NT-proBNP) concentrations. RESULTS: Arterial and venous concentrations of all factors analysed showed no statistical difference (all p values > 0.1); leptin A: 39 ± 16 vs. V: 42 ± 18 ng/mL; total ghrelin A : 0.86 ± 0.27 vs. V : 0.76 ± 0.35 ng/mL; adiponectin A: 7.7 ± 3.3 vs. V: 7.7 ± 3.6 μg/mL; insulin A: 17.9 ± 9.7 vs. V: 18.6 ± 10.5 μU/mL; glucose A: 8.3 ± 2.1 vs. V: 7.9 ± 2.2 mM; NEFA A: 0.98 ± 0.93 vs. V: 0.89 ± 0.38 mM ; hs-CRP A: 10.17 ± 7.68 vs. V: 10.27 ± 7.30 μg/mL and NT-proBNP A: 54.3 ± 47.9 vs. V: 54.7 ± 49.3 pg/mL. CONCLUSION: These results suggest that radial artery and superior vena cava blood collection sites are comparable and may be used clinically with respect to fasting glucose, NEFA, leptin, adiponectin, total ghrelin, hs-CRP and NT-proBNP concentrations in a group of severely obese patients.