1013-113 Is Diabetic “Hyperadrenergic Orthostatic Hypotension” due to End Organ Resistance to Catecholamines?

• Published in: Journal of the American College of Cardiology 1995-02, Vol.25 (2), p.369A-369A
• Main Authors: Hajjar, Riad R., Shehadeh, Abbas, Waness, Abdelkarim, Bravo, Emmanuel L., Fouad-Tarazi, Fetnat M.
• Format: Article
• Language: English
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/0735-1097(95)92988-H

It has been previously reported that orthostatic hypotension occurs in some diabetics despite markedly increased standing plasma norepinephrine. The mechanism for this response remains unclear. We hypothesized that this “hyperadrenergic response” is triggered by accentuated postural venous translocation of blood volume (venous pooling). We assessed the hemodynamic (99m Tc-RBC) and catecholamine responses to upright posture in 54 diabetic patients (30 M: 24 F, age 57.5±13 yrs). Venous translocation was defined by the ratio of cardiopulmonary volume (CPV) to total blood volume (TBV, RISA method). Total peripheral resistance was calculated from cardiac output and blood pressure. Based on upright plasma norepinephrine (UPNE). patients were classified as: hyperadrenergic if UPNE is >558 pg/ml, hypoadrenergic if UPNE <495 and normal adrenergic response if 494 >UPNE <558. Within each group, orthostatic hypotension OH + was defined as a decrease in systolic blood pressure of >20 mmHg during tilt. HyperAdrHypoAdrNorm AdrOH+OH-OH+OH-OH+OH–n126151047ΔSBP mmHg-55±25-12±6*-53±23-8±8*-62±112±24*ΔHR BPM6±97±713±184±613±1811±8ΔTPR U.M20.8±712±1.40.4±74±84±411±8ΔCPV/TBV%-2±1-2.5±3-1±3-1±2-2±1-2±3ΔPNE Pg/ml456±512369±19849±80†98±65†284±33238±114x¯ ± SD*p<0.0001 YS OH+ (HyperA, HypoA & Norm A)†P<0.01 YS OH+ (HyperA). TPR=total peripheral resistance Contrary to our hypothesis, orthostatic venous pooling was not accentuated in diabetics with hyperadrenergic OH+. Their disease is probably due to end organ resistance to plasma norepinephrine.