Postprandial hypotension: lessons from Sir Roger Bannister's textbook

In the fourth and final article of the Neurocardiology series, Helen Cowan looks at postprandial hypotension as described in Sir Roger Bannister's textbook and subsequent research.

The Glycemic Index, Postprandial Hypotension and Cardiovascular Disease

High glycemic index diets have been associated with an increased risk of cardiovascular disease events and all-cause mortality. We suggest that part of the reason for this association is through the effect of the rapidly digested high glycemic index carbohydrate diets in promoting the effects of postprandial hypotension in vulnerable individuals. Postprandial hypotension has been recognized as a problem especially affecting the frail elderly. The phenomenon occurs earlier in the day and includes syncope and falls acutely and more serious cardiovascular events and increased all-cause mortality in the longer-term. The mechanism appears to relate to the rapid digestion of carbohydrates foods. Strategies that reduce the amount of meal carbohydrates and their rate of absorption by enzyme inhibition or by delaying gastric emptying and have proved helpful as has increased fluid intake, presumably due to dilution of small intestinal contents and a reduction in the tonicity, so reducing the need for intestinal fluid secretion to dilute osmotically active sugars and products of digestion. In this way the need for increased blood flow to the gut can be reduced, that would otherwise steal blood from the systemic circulation resulting in a drop in blood pressure and an increase in heart rate. Slowly absorbed or low glycemic index carbohydrates would therefore appear potentially useful as part of the dietary strategy for the treatment of postprandial hypotension and conversely postprandial hypotension could be one of the reasons why high glycemic index diets have been associated with increased CVD risk.

Potential for Gut Peptide-Based Therapy in Postprandial Hypotension

Postprandial hypotension (PPH) is an important and under-recognised disorder resulting from inadequate compensatory cardiovascular responses to meal-induced splanchnic blood pooling. Current approaches to management are suboptimal. Recent studies have established that the cardiovascular response to a meal is modulated profoundly by gastrointestinal factors, including the type and caloric content of ingested meals, rate of gastric emptying, and small intestinal transit and absorption of nutrients. The small intestine represents the major site of nutrient-gut interactions and associated neurohormonal responses, including secretion of glucagon-like peptide-1, glucose-dependent insulinotropic peptide and somatostatin, which exert pleotropic actions relevant to the postprandial haemodynamic profile. This review summarises knowledge relating to the role of these gut peptides in the cardiovascular response to a meal and their potential application to the management of PPH.

Acarbose for Postprandial Hypotension With Glucose Metabolism Disorders: A Systematic Review and Meta-Analysis

Background: Postprandial hypotension (PPH) is an independent predictive factor of all-cause mortality in older people. Drug management has not achieved a satisfactory effect yet. In recent years, many studies have found that acarbose may be effective in the treatment of PPH with glucose metabolism disorders.Objective: To assess the efficacy and safety of acarbose on PPH with glucose metabolism disorders.Methods: PubMed (MEDLINE), Cochrane, EMBASE, Web of Science, Clinical Trials, and relevant Chinese databases were searched from inception to October 1, 2020. Randomized controlled studies of acarbose in the treatment of PPH with glucose metabolism disorders were included. Review Manager 5.3 software was used for quality evaluation and meta-analysis. GRADEpro GDT software was used to GRADE the evidence for the research objectives.Results: A total of 4 randomized controlled studies including 202 participants were identified after screening. The meta-analysis showed that acarbose significantly attenuated the decrease in postprandial systolic blood pressure [weighted mean difference (MD): −9.84, 95% CI: −13.34 to −6.33], diastolic blood pressure (MD: −6.86, 95% CI: −12.89 to −0.83), and mean arterial pressure (MD: −8.10, 95% CI: −12.40 to −3.49) compared with the control group. One study reported a case of adverse reactions that included mild abdominal distension in the acarbose group (4.8%, 1/21). No adverse reactions were reported in the other three studies.Conclusion: Acarbose may attenuate the decrease in postprandial blood pressure and avoid the occurrence of PPH in patients with PPH and abnormal glucose metabolism disorders. More clinical trials are needed to make a clear conclusion.Registration: PROSPERO CRD42020171335.

Postprandial Hypotension and Spinal Cord Injury

Postprandial hypotension (PPH) is defined as a fall of ≥20 mmHg in systolic blood pressure (SBP) or a SBP of <90 mmHg after having been >100 mmHg before the meal within two hours after a meal. The prevalence of PPH among persons with spinal cord injury (SCI) is unknown. Ambulatory blood pressure measurement was performed in 158 persons with SCI, 109 men, median age was 59.1 years (min.:13.2; max.: 86.2). In total, 78 persons (49.4%) had PPH after 114 out of 449 meals (25.4%). The median change in SBP during PPH was −28 mmHg (min.: −87; max.: −15 mmHg) and 96% of the PPH episodes were asymptomatic. The occurrence of PPH was correlated to older age (p = 0.001), level of injury (p = 0.023), and complete SCI (p = 0.000), but not, gender or time since injury. Further studies are needed to elucidate if PPH contributes to the increased cardiovascular mortality in the SCI population.

Prevalence and Risk Factors of Postprandial Hypotension Among Japanese Older Adults in a Facility

Postprandial hypotension (PPH) is an unrecognized sudden drop of blood pressure (BP) after meals and a hidden problem among older people including those living in long-term care facilities (LTCFs). Though PPH causes dizziness, falls, and syncope, it has received little attention from¬¬¬ healthcare workers (HCW) including caregivers, nurses and physicians, and risk factors of PPH should be carefully assessed to improve quality of life. Therefore, we aimed to examine the prevalence and risk factors of PPH in a LTCF in Japan. Participants were 114 older adults living in a LTCF in Japan (mean age 85.9 years old; 85 female (74%)). To examine PPH, blood pressure (BP) was measured before and after lunch. BP after meal was measured four times every 30 minutes. PPH is defined as a BP drop of 20 mmHg or more and we also defined a BP drop within a range of 19 to 15 mmHg as potential-PPH. As risk factors, we compared systolic and diastolic BP at baseline, body mass index, pulse rate, disease and complications between groups with/without PPH. The prevalence of PPH was 41% (47/114) and 52% with potential-PPH; 11% (13/114) added. Among risk factors, systolic BP was significantly higher in those with PPH (142.6 vs 123.5 mmHg, p &lt;0.001). This study revealed that PPH & potential-PPH occurred in half of the subjects in a LTCF in Japan. HCW need to focus on high systolic BP to predict PPH and future research is necessary to prevent and cope with PPH for older people.

Postprandial Hypotension: Lessons from Sir Roger Bannister's Textbook

In the fourth article of the new Neurocardiology series, Helen Cowan looks at postprandial hypotension as described in Sir Roger Bannister's textbook and subsequent research.