Objective: To show the clinical relevance of postprandial hypotension and to review its pathophysiology and management. Data Sources: Articles on postprandial hypotension were identified through ME...

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Postprandial Hypotension : Epidemiology, Pathophysiology, and Clinical Management

Dialysis hypotension: A hemodynamic analysis

BACKGROUND. Although postprandial hypotension is a common cause of falls and syncope in elderly persons and in patients with autonomic insufficiency, the pathophysiology of this disorder remains unknown. METHODS AND RESULTS. We examined the hemodynamic, splanchnic blood pool, plasma norepinephrine (NE), and heart rate (HR) power spectra responses to a standardized 400-kcal mixed meal in 11 healthy young (age, 26 +/- 5 years) and nine healthy elderly (age, 80 +/- 5 years) subjects and 10 dysautonomic patients with symptomatic postprandial hypotension (age, 65 +/- 16 years). Cardiac and splanchnic blood pools were determined noninvasively by radionuclide scans, and forearm vascular resistance was determined using venous occlusion plethysmography. In healthy young and old subjects, splanchnic blood volume increased, but supine blood pressure remained unchanged after the meal. In both groups, HR increased and systemic vascular resistance remained stable. Forearm vascular resistance and cardiac index increased after the meal in elderly subjects, whereas these responses were highly variable and of smaller magnitude in the young. Young subjects demonstrated postprandial increases in low-frequency HR spectral power, representing cardiac sympatho-excitation, but plasma NE remained unchanged. In elderly subjects, plasma NE increased after the meal but without changes in the HR power spectrum. Patients with dysautonomia had a large postprandial decline in blood pressure associated with no change in forearm vascular resistance, a fall in systemic vascular resistance, and reduction in left ventricular end diastolic volume index. HR increased in these patients but without changes in plasma NE or the HR power spectrum. CONCLUSIONS. 1) In healthy elderly subjects, the maintenance of blood pressure homeostasis after food ingestion is associated with an increase in HR, forearm vascular resistance, cardiac index, and plasma NE. In both young and old, systemic vascular resistance is maintained. 2) Dysautonomic patients with postprandial hypotension fail to maintain systemic vascular resistance after a meal. This impairment in vascular response to meal ingestion may underlie the development of postprandial hypotension. 3) The measurement of mean HR or plasma NE does not adequately characterize autonomic cardiac control. Power spectral analysis suggests an impairment in the postprandial autonomic modulation of HR in healthy elderly and dysautonomic subjects, possibly predisposing to hypotension when vascular compensation is inadequate.

Hemodynamic and autonomic nervous system responses to mixed meal ingestion in healthy young and old subjects and dysautonomic patients with postprandial hypotension.

▪Objective:To determine the frequency and importance of postprandial reductions in systolic blood pressure in debilitated, elderly patients receiving nursing home care. ▪Design:Cohort stud...

Frequency and Importance of Postprandial Blood Pressure Reduction in Elderly Nursing-Home Patients

Context: An association has been suggested between elevated plasma nonesterified fatty acid (NEFA) levels, myocardial triglyceride (TG) accumulation, and myocardial function. Objective: Our objective was to investigate the effects of an elevation of plasma NEFA by a high-fat, high-energy (HFHE) diet on hepatic and myocardial TG accumulation, and on myocardial function. Design: There were 15 healthy males (mean ± sd age: 25.0 ± 6.6 yr) subjected to a 3-d HFHE diet consisting of their regular diet, supplemented with 800 ml cream (280 g fat) every day. Methods: 1H-magnetic resonance spectroscopy was performed for assessing hepatic and myocardial TGs. Furthermore, left ventricular function was assessed using magnetic resonance imaging. Results: The HFHE diet increased hepatic TGs compared with baseline (from 2.01 ± 1.79 to 4.26 ± 2.78%; P = 0.001) in parallel to plasma TGs and NEFA. Myocardial TGs did not change (0.38 ± 0.18 vs. 0.40 ± 0.12%; P = 0.7). The HFHE diet did not change myocardial systolic function...

Effects of short-term high-fat, high-energy diet on hepatic and myocardial triglyceride content in healthy men.

The effects of a standardized mixed meal, a self-selected meal and a sham meal on heart rate, arterial pressure, cardiac output, total systemic resistance and echocardiographic indexes of left ventricular performance were examined in normal volunteers. Supine heart rate and cardiac output increased after the meals (p less than 0.07 to 0.001), but not after the sham meal. Supine diastolic blood pressure and total systemic resistance decreased after the meals but not after the sham meal (p less than 0.05 to 0.001). Ejection fraction and mean velocity of circumferential fiber shortening increased after the standard meal (p less than 0.01) and tended to increase after the self-selected meal, but did not increase after the sham meal. Meals of normal size may induce splanchnic vasodilation and a decrease in total systemic resistance. Ingestion of food also significantly affects heart rate, blood pressure, cardiac output and echocardiographic indexes of left ventricular performance. Patients should not eat during short-term evaluation of cardiovascular interventions because the cardiovascular effects of a meal may compromise interpretation of the cardiovascular effects of the primary intervention. The hemodynamic effects of food may also interact with the effects of cardiovascular disease processes.

Lynn A. Gourley

Papers

Postprandial alterations in hemodynamics and blood pressure in normal subjects.