Treatment of postprandial hypotension with selective alpha 1 and beta 1 adrenergic agonists

Postprandial cerebral infarction

Some neurological diseases are accompanied by autonomic dysfunction. Postprandial hypotension (PPH) is one disorder accompanied by autonomic dysfunction. Although the major symptoms of PPH are fall and syncope, PPH is sometimes overlooked because of its non-specific symptoms, such as dizziness, nausea, and light-headedness. Because PPH could result in decreased cerebral perfusion pressure accompanied by a decrease in blood pressure, PPH may be linked to the risk of hemodynamic stroke or transient ischemic events, especially in patients with chronic cerebral large vessel occlusion/stenosis. Whether chronic cerebral large vessel occlusion or stenosis causes symptomatic ischemic events depends on the patient's compensatory collateral circulation and cerebral vasoreactivity. Therefore, we hypothesized that cerebral blood flow assessment could be essential for stratifying patients at high risk of postprandial cerebral infarction. However, there have been few reports on the association between cerebral blood flow and the occurrence of postprandial cerebral infarction. In a literature review, we identified seven cases of postprandial cerebral infarction. Postprandial cerebral infarction occurs in patients with chronic cerebral large vessel occlusion/stenosis accompanied by cerebral blood flow reduction. Non-pharmacotherapeutic and pharmacotherapeutic approaches could improve postprandial cerebral infarction; however, one patient with poor compensatory collateral circulation and reduced cerebral vasoreactivity experienced recurrent symptomatic episodes even with sufficient medical treatment and needed extracranial-intracranial bypass surgery. Physicians should be aware of PPH as it can complicate neurological disorders. Long-term blood pressure monitoring for the detection of PPH and cerebral blood flow assessment is needed in patients with cerebral large vessel occlusion/stenosis to prevent postprandial cerebral infarction.

Acute Effects of Nutritive and Non-Nutritive Sweeteners on Postprandial Blood Pressure

Postprandial hypotension (PPH) is under-recognised, but common, particularly in the elderly, and is of clear clinical importance due to both the independent association between PPH and an increase in mortality and lack of effective management for this condition. Following health concerns surrounding excessive consumption of sugar, there has been a trend in the use of low- or non-nutritive sweeteners as an alternative. Due to the lack of literature in this area, we conducted a systematic search to identify studies relevant to the effects of different types of sweeteners on postprandial blood pressure (BP). The BP response to ingestion of sweeteners is generally unaffected in healthy young subjects, however in elderly subjects, glucose induces the greatest decrease in postprandial BP, while the response to sucrose is less pronounced. The limited studies investigating other nutritive and non-nutritive sweeteners have demonstrated minimal or no effect on postprandial BP. Dietary modification by replacing high nutritive sweeteners (glucose, fructose, and sucrose) with low nutritive (d-xylose, xylitol, erythritol, maltose, maltodextrin, and tagatose) and non-nutritive sweeteners may be a simple and effective management strategy for PPH.

Possible Involvement of Hypotension in Postprandial Headache: A Case Series

BACKGROUND

It is commonly known that headaches are induced by intake of specific food, drink, and/or additive. In addition, some patients experience postprandial headache independent of ingestion of specific items. Currently, information on the pathophysiology underlying this particular type of headache is scarce.

CASE REPORTS

We report two cases in which headaches were observed after each meal. Postprandial hypotension was demonstrated in both cases. Tonometry-based continuous blood pressure measurement during head-up tilt revealed sympathetic dysfunction. In one patient, meta-iodobenzylguanidine (MIBG) myocardial scintigraphy detected cardiac sympathetic denervation, and diagnosis of pure autonomic failure was made. In both cases, treatment of postprandial hypotension was effective in relieving postprandial headache.

DISCUSSION

The possibility of postprandial hypotension should be explored in patients with headache that occurs after meal. To this end, tonometry-based blood pressure measurement and MIBG myocardial scintigraphy may be useful diagnostic investigations. Treating postprandial hypotension may be effective in alleviating the symptoms.

Postprandial hypotension: a systematic review

BACKGROUND

Postprandial hypotension (PPH) is an important clinical problem, which has received inappropriately little attention.

METHODS

A systematic search of the databases PubMed, Embase, Cochrane Library, and Web of Knowledge, from their inception to the present time, was conducted to identify studies relevant to the epidemiology, pathophysiology, and/or management of PPH.

RESULTS

A total of 417 full-text papers were retrieved from database searching and, following screening, 248 were retained. Of these, 167 papers were considered eligible for inclusion.

CONCLUSIONS

PPH occurs commonly in older people and represents a major cause of morbidity. Although the pathophysiology of PPH remains poorly defined, diverse factors, including impairments in sympathetic and baroreflex function, release of vasodilatory peptides, the rate of small intestinal nutrient delivery, gastric distension, and splanchnic blood pooling, appear important. Current pharmacologic and nonpharmacologic management is suboptimal. Research into the pathophysiology of PPH represents a priority so that management can be targeted more effectively.

Pharmacological treatment of postprandial reductions in blood pressure: a systematic review

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

Postprandial hypotension is both common in geriatric patients and an important but under-recognized cause of syncope. Other populations at risk include those with Parkinson disease and autonomic failure. The mechanism is not clearly understood, but appears to be secondary to a blunted sympathetic response to a meal. This review discusses the epidemiology, risk factors, and pathophysiology of postprandial hypotension in the elderly, as well as diagnosis and treatment strategies. Diagnosis can be made based on ambulatory blood pressure monitoring and patient symptoms. Lifestyle modifications such as increased water intake before eating or substituting 6 smaller meals daily for 3 larger meals may be effective treatment options. However, data from randomized, controlled trials are limited. Increased awareness of this disease may lead to improved quality of life, decreased falls and injuries, and the avoidance of unnecessary testing.

Altered venous capacitance as a cause of postprandial hypotension in multiple system atrophy

Patients with multiple system atrophy (MSA) often have clinically significant postprandial hypotension (PPH). To elucidate the cause of insufficient cardiac preload augmentation that underlies PPH, we recorded calf venous capacitance (CVC) by strain-gauge plethysmography, in 17 MSA patients and eight healthy controls before and after oral glucose ingestion. Among 17 MSA patients, nine who showed a decrease in systolic blood pressure exceeding 20 mmHg and were diagnosed with PPH. MSA patients without PPH showed a significant decrease in CVC and a significant increase in cardiac output after oral glucose ingestion, as did controls; those with MSA exhibiting PPH showed a significant increase in CVC and no significant change in cardiac output. The change in CVC correlated positively with the decrease in systolic and diastolic blood pressure after glucose ingestion, and also correlated negatively with the increase in cardiac output. Physiologically, PPH is prevented by a decrease in venous capacitance, which increases circulating blood volume and cardiac output. In some MSA patients, failure of venous capacitance to decrease may induce PPH.

Postprandial hypotension

Postprandial hypotension is a prevalent condition in the elderly population and seems to be more common in frail elderly individuals who may be more susceptible to complications such as syncope and falls. Diagnosis is relatively easy and may be reversible in many cases. The epidemiology and pathophysiology of postprandial hypotension are not defined fully; however, a number of pathologic processes likely are involved, including abnormal sympathetic function, baroreceptor function, and vasoactive peptide release and activity. The precise relationship between symptoms and postprandial reductions in blood pressure is unclear. Blood pressure maintenance after a meal may depend on the interaction of some or all of the mechanisms outlined previously to compensate for the increase in bowel blood volume. The impairment of one or more of these mechanisms could result in inadequate compensation that leads to hypotension. If so, the presence of symptoms depends on that individual patient's ability to exercise adequate compensatory cerebral autoregulation. A hypertensive elderly patient may experience symptoms with only a small reduction in blood pressure, whereas a patient with autonomic failure may require a much larger fall in blood pressure to occur before they become symptomatic. The current definition of postprandial hypotension uses a threshold of 20 mm Hg as a cut off for diagnosis, but this may not be relevant to the presence or absence of symptoms. Further epidemiologic data are needed. Additionally, there is a lack of controlled trial evidence for the drugs that are used to treat this condition, and treatment often is carried out on a trial-and-error basis. Further research must be performed to identify the specific pathophysiology in certain patient groups, such as elderly hypertensive patients and those with autonomic failure, and to identify effective pharmacologic therapies that can be supported by randomized, placebo-controlled trials.

Midodrine: a selective alpha-adrenergic agonist for orthostatic hypotension and dialysis hypotension

Midodrine is an oral agent which acts as a selective peripherally-acting alpha-receptor agonist. Midodrine is a prodrug that is almost completely absorbed after oral administration and converted into its active drug de-glymidodrine in the systematic circulation, with a bioavailability of 93%. It has been used successfully in the treatment of neurogenic orthostatic hypotension and more recently, in the treatment of dialysis hypotension. It acts through vasoconstriction of the arterioles and the venous capacitance vessels, thereby increasing peripheral vascular resistance and augmenting venous return, respectively. It is a unique agent in the armamentarium against orthostatic hypotension since it has minimal cardiac and CNS effects. This article will review the literature on midodrine for conditions of autonomic dysfunction, with focus on recent studies on its use in haemodialysis patients.

Effects of meal ingestion and active standing on blood pressure in patients > or = 60 years of age

Postprandial hypotension and orthostatic hypotension occur often in elderly patients. In the present study, we examined hemodynamic and humoral responses to meal ingestion and active standing in 20 patients > or = 60 years of age who were free of apparent autonomic and cardiac dysfunction. For a time-control study, water was given instead of a meal to 19 of the 20 patients. After the meal ingestion, there was a fall in systolic blood pressure (BP) in 6 patients of > 20 mm Hg, whereas the fall in systolic BP during the control study was not > 20 mm Hg in any patient. The low-frequency power of the systolic BP wave, an index of peripheral sympathetic activity, was significantly increased only in the patients without postprandial hypotension. The postprandial changes in systolic BP were correlated with the changes in the low-frequency power of the systolic BP wave (r = 0.61; p < 0.01), but they were not correlated with the changes in plasma norepinephrine, insulin, cardiac output, or parameters obtained by the spectral analysis of the RR interval. The systolic BPs in the upright position were comparable after the meal and the water ingestion. Thus, the effects of meal ingestion and upright position on BP are not additive. Dysfunction of peripheral sympathetic control of vascular tone may contribute to the postprandial hypotension in elderly patients.

Treatment of orthostatic hypotension with midodrine and octreotide

The purpose of this study was to compare two treatments for orthostatic hypotension, midodrine (an alpha adrenergic agonist), and octreotide (an SRIH analogue) to each other and to combination therapy. Sixteen patients participated. Our hypothesis was that the 2 drugs together would be more effective than either drug alone. The effect of the drugs on the hemodynamic response to food ingestion was evaluated while patients were sitting. Midodrine (5 mg orally, 30 min before breakfast) increased mean blood pressure slightly (5-10 mm Hg, over 30 min) before the patients started eating, but it only partially reversed the hypotensive effect of food ingestion. The nadir in postprandial blood pressure after midodrine was 69 +/- 4 mm Hg, not different from placebo (63 +/- 5). Nevertheless, midodrine accentuated the response to sc octreotide (0.5 microgram/kg). Fifteen minutes after octreotide administration to midodrine-pretreated patients, the average mean blood pressure was 115 +/- 9 mm Hg, higher (P = .0095) than after octreotide given alone (102 +/- 7). Drug effects on orthostatic hypotension were assessed by measuring standing time (minutes before symptoms of hypotension or definite hypotension). In the absence of treatment, standing time was 3.5 +/- 7 min; 1 h after 10 mg midodrine, 8.4 +/- 2.7 min (P = .11); after 1.0 microgram/kg octreotide, 13.2 +/- 3.9 min (P = .0034 vs. no treatment); and after both drugs, 21.2 +/- 5.5 min (P = .0002 vs. no treatment, P = .036 vs. octreotide only). The combination of midodrine and octreotide is more potent than either drug alone.

Treatment of postprandial hypotension in the elderly

Food intake induces splanchnic vasodilation lasting for at least one hour, which can precipitate in postprandial hypotension, if systolic arterial blood pressure falls by more than 20 mmHg. Postprandial hypotension has a high prevalence in the elderly, above all in subjects receiving hypotensive drugs or in those with disorders of the autonomic nervous system. In our total case series of 567 subjects, the prevalence of postprandial hypotension evaluated by 24-hr blood pressure recording, was 14.5%, increasing to 28% in the oldest group. Since relevant cerebral ischemic symptoms may become manifest, a correct diagnosis of the disorder and both pharmacological and non-pharmacological therapeutical approaches are of great importance for the wellbeing of old patients.

Postural hypotension in diabetic autonomic neuropathy: a review

Postural hypotension is uncommon in diabetes but can occur secondary to autonomic neuropathy. Symptoms are rare and include dizziness, weakness, blurred vision, tiredness, and loss of consciousness. The pathophysiology of postural hypotension is not clear, but changes in intravascular volume, heart rate, cardiac output, and splanchnic vascular resistance are similar in patients and controls. The main factors producing hypotension are a blunted catecholamine response to standing, and failure of lower limb vascular resistance to increase adequately. Treatment for symptomatic postural hypotension includes avoidance of dehydration, adequate salt intake, and fludrocortisone. Other treatments are reviewed but are less helpful. Patients with postural hypotension have intermittent symptoms over the years but rarely become severely disabled. They have a poorer prognosis than patients with symptomatic autonomic neuropathy without postural hypotension.