Treatment of Postprandial Reductions in Blood Pressure
Treatment of Postprandial Reductions in Blood Pressure
Objectives: To systematically review the current literature on the pharmacological treatment of postmeal reductions in blood pressure (BP).
Design: A systematic literature search and standardized data collection of randomized controlled trials on the pharmacological prevention of postprandial reductions in BP in adults using MEDLINE (1950–), EMBASE (1980–), and CINAHL databases was conducted up to July 2013. Bibliographies of relevant reports were also hand-searched to identify all potentially eligible studies.
Setting: Systematic review of randomized controlled trials using PRISMA guidelines.
Measurements: Articles were assessed using the Critical Appraisal Skills Programme for randomized controlled trials.
Results: Thirteen articles reporting 12 studies (1 study was reported in 2 articles) demonstrated that caffeine (5 studies); acarbose; 3,4-DL-threo-dihydroxyphenylserine; guar gum (3 studies); and octreotide (2 studies) statistically attenuated the postprandial reduction in BP. One caffeine study did not show this. Most studies did not include individuals with symptomatic postprandial hypotension (PPH), so interpretation and application of these findings to this patient group should be made with caution. For symptomatic participants, there was improvement with acarbose but none with caffeine. Differences in the way the data were presented in the studies did not allow for quantification of treatment effects using meta-analysis.
Conclusion: Drug interventions can attenuate postprandial reductions in BP, but they may not necessarily be effective in people with symptomatic PPH.
Postprandial hypotension (PPH) can be defined as a reduction in systolic blood pressure (SBP) of 20 mmHg or more within 2 hours of the start of a meal or if SBP falls to 90 mmHg or less within this period if preprandial SBP was 100 mmHg or greater. Postprandial reductions in BP are much more common in older than younger people, with prevalence rates of up to 36% of those residing in care homes and as high as 67% in the older hospital population.
Symptomatic PPH can result in dizziness, falls, confusion, visual disturbances, nausea, tiredness, syncope, and poor quality of life. Although PPH may not always be associated with symptoms, the clinical effect can be substantial, being present in half of those with "unexplained" syncope, as well as being associated with acute vascular events such as stroke and angina pectoris and mortality.
The largest postprandial reductions in BP are seen in those aged 65 and older and usually occur within 60 to 120 minutes of ingestion of an energy source (liquid or solid). This is particularly the case when there is a high simple carbohydrate substrate content (e.g., glucose but not fructose). The postprandial reduction in BP is independent of the presence or absence of systemic hypertension even when antihypertensive medication is withdrawn. This postprandial reduction in BP reflects the failure of the normal homeostatic mechanisms to maintain BP levels in the face of a reduction in systemic vascular resistance due to splanchnic and peripheral vasodilation not being compensated for by an increase in cardiac output.
Evidence suggests that caffeine (an adenosine antagonist that blocks splanchnic methylxanthine-sensitive adenosine receptors) when given after meals can reduce postprandial symptoms and reductions in BP, indicating that adenosine may have an underlying pathophysiological role in inducing this splanchnic vasodilatation. Other studies have shown that there is also impairment of cardiac baroreflex sensitivity in older people, resulting in impaired heart rate (HR) and stroke volume responses and leading to failure to increase cardiac output to compensate for the reduction in systemic vascular resistance.
In addition to some lifestyle measures, several other agents have also been tried in the treatment of PPH by addressing possible underlying pathophysiological mechanisms. For example, acarbose reduces complex carbohydrate breakdown, delaying gut glucose absorption. Whereas 3,4- DL-threo-dihydroxyphenylserine (DL-DOPS), is a norepinephrine precursor that converts to norepinephrine in the peripheral and central nervous system to replace levels of norepinephrine in autonomic failure. Guar gum reduces postprandial reductions in BP by delaying gastric emptying and glucose absorption in the small intestine. Other agents such as octreotide (which inhibits the vasodilation of the splanchnic vasculature by inhibiting vasoactive peptides) given before a meal have been also been shown to have some benefit in preventing PPH in older adults with hypertension, as has midodrine (an α1-adrenergic agonist) administered concomitantly with denopamine (a selective β1-adrenergic agonist).
Although there is some evidence of these agents being useful in this setting, the magnitude of the effects of these therapeutic agents in a randomized controlled trial setting has not been examined systematically. Herein is reported a systematic review of randomized controlled trials involving the pharmacological management of PPH and postprandial reductions in BP using PRISMA guidelines.
Abstract and Introduction
Abstract
Objectives: To systematically review the current literature on the pharmacological treatment of postmeal reductions in blood pressure (BP).
Design: A systematic literature search and standardized data collection of randomized controlled trials on the pharmacological prevention of postprandial reductions in BP in adults using MEDLINE (1950–), EMBASE (1980–), and CINAHL databases was conducted up to July 2013. Bibliographies of relevant reports were also hand-searched to identify all potentially eligible studies.
Setting: Systematic review of randomized controlled trials using PRISMA guidelines.
Measurements: Articles were assessed using the Critical Appraisal Skills Programme for randomized controlled trials.
Results: Thirteen articles reporting 12 studies (1 study was reported in 2 articles) demonstrated that caffeine (5 studies); acarbose; 3,4-DL-threo-dihydroxyphenylserine; guar gum (3 studies); and octreotide (2 studies) statistically attenuated the postprandial reduction in BP. One caffeine study did not show this. Most studies did not include individuals with symptomatic postprandial hypotension (PPH), so interpretation and application of these findings to this patient group should be made with caution. For symptomatic participants, there was improvement with acarbose but none with caffeine. Differences in the way the data were presented in the studies did not allow for quantification of treatment effects using meta-analysis.
Conclusion: Drug interventions can attenuate postprandial reductions in BP, but they may not necessarily be effective in people with symptomatic PPH.
Introduction
Postprandial hypotension (PPH) can be defined as a reduction in systolic blood pressure (SBP) of 20 mmHg or more within 2 hours of the start of a meal or if SBP falls to 90 mmHg or less within this period if preprandial SBP was 100 mmHg or greater. Postprandial reductions in BP are much more common in older than younger people, with prevalence rates of up to 36% of those residing in care homes and as high as 67% in the older hospital population.
Symptomatic PPH can result in dizziness, falls, confusion, visual disturbances, nausea, tiredness, syncope, and poor quality of life. Although PPH may not always be associated with symptoms, the clinical effect can be substantial, being present in half of those with "unexplained" syncope, as well as being associated with acute vascular events such as stroke and angina pectoris and mortality.
The largest postprandial reductions in BP are seen in those aged 65 and older and usually occur within 60 to 120 minutes of ingestion of an energy source (liquid or solid). This is particularly the case when there is a high simple carbohydrate substrate content (e.g., glucose but not fructose). The postprandial reduction in BP is independent of the presence or absence of systemic hypertension even when antihypertensive medication is withdrawn. This postprandial reduction in BP reflects the failure of the normal homeostatic mechanisms to maintain BP levels in the face of a reduction in systemic vascular resistance due to splanchnic and peripheral vasodilation not being compensated for by an increase in cardiac output.
Evidence suggests that caffeine (an adenosine antagonist that blocks splanchnic methylxanthine-sensitive adenosine receptors) when given after meals can reduce postprandial symptoms and reductions in BP, indicating that adenosine may have an underlying pathophysiological role in inducing this splanchnic vasodilatation. Other studies have shown that there is also impairment of cardiac baroreflex sensitivity in older people, resulting in impaired heart rate (HR) and stroke volume responses and leading to failure to increase cardiac output to compensate for the reduction in systemic vascular resistance.
In addition to some lifestyle measures, several other agents have also been tried in the treatment of PPH by addressing possible underlying pathophysiological mechanisms. For example, acarbose reduces complex carbohydrate breakdown, delaying gut glucose absorption. Whereas 3,4- DL-threo-dihydroxyphenylserine (DL-DOPS), is a norepinephrine precursor that converts to norepinephrine in the peripheral and central nervous system to replace levels of norepinephrine in autonomic failure. Guar gum reduces postprandial reductions in BP by delaying gastric emptying and glucose absorption in the small intestine. Other agents such as octreotide (which inhibits the vasodilation of the splanchnic vasculature by inhibiting vasoactive peptides) given before a meal have been also been shown to have some benefit in preventing PPH in older adults with hypertension, as has midodrine (an α1-adrenergic agonist) administered concomitantly with denopamine (a selective β1-adrenergic agonist).
Although there is some evidence of these agents being useful in this setting, the magnitude of the effects of these therapeutic agents in a randomized controlled trial setting has not been examined systematically. Herein is reported a systematic review of randomized controlled trials involving the pharmacological management of PPH and postprandial reductions in BP using PRISMA guidelines.
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