起立性低血圧症の原因

起立性低血圧症を来す病態と疾患
参考文献：
  1. Task Force for the Diagnosis and Management of Syncope; European Society of Cardiology (ESC); European Heart Rhythm Association (EHRA); Heart Failure Association (HFA); Heart Rhythm Society (HRS)．Guidelines for the diagnosis and management of syncope (version 2009). Eur Heart J 2009; 30: 2631-2671.
  1. Hopson JR, Rea RF, Kienzle MG. Alterations in reflex function contributing to syncope: orthostatic hypotension, carotid sinus hypersensitivity and drug-induced dysfunction. Herz 1993; 18: 164-174.
  1. Hanlon JT, Linzer M, MacMillan JP, et al. Syncope and presyncope associated with probable adverse drug reactions. Arch Intern Med 1990; 150: 2309-2312.
  1. Cherin P, Colvez A, Deville de Periere G, et al. Risk of syncope in the elderly and consumption of drugs: a casecontrol study. J Clin Epidemiol 1997; 50: 313-320.
  1. Calkins H, Zipes DP. Hypotension and syncope. In: Zipes DP, Libby P, Bonow RO, Braunwald E, editors. Braunwald’s Heart disease. A Textbook of Cardiovascular Medicine.7th ed. Philadelphia, Elsevier Saunders 2005: 909-919.
出典
img
1: 著者提供

Tilt試験時の血圧変動

当院で経験した起立性低血圧の症例のTilt試験の結果である。
出典
img
1: 著者提供

高齢者における起立性低血圧症のさまざまな定義を用いてCox回帰分析を行った、死亡率に対する粗ハザードおよび補正ハザード比（HR）

高齢者のうち起立性低血圧のある群では、ない群に比べ死亡率が高い。
出典
imgimg
1: Prognosis of diastolic and systolic orthostatic hypotension in older persons.
著者: Luukinen H, Koski K, Laippala P, Kivelä SL.
雑誌名: Arch Intern Med. 1999 Feb 8;159(3):273-80. doi: 10.1001/archinte.159.3.273.
Abstract/Text: BACKGROUND: Orthostatic hypotension (OH) predicts mortality in hypertensive persons with diabetes mellitus, but no increase in mortality has been found among random samples of home-dwelling persons with OH. We examined the risks of nonvascular and vascular deaths according to different definitions of OH among home-dwelling elderly persons.
SUBJECTS AND METHODS: The study population consisted of all persons aged 70 years or older living in 5 rural municipalities (N=969), of whom 833 (86%) participated. Orthostatic tests were successfully carried out in 792 persons by nurse examiners. Orthostatic hypotension was defined as a systolic blood pressure (BP) drop of 20 mm Hg or more or a diastolic BP drop of 10 mm Hg or more 1 minute or 3 minutes after standing up. Nonvascular and vascular deaths during the follow-up period were recorded. Data on diseases, symptoms, medications, the results of clinical examinations and tests, functional ability, and health behavior were collected at the beginning of the follow-up period.
RESULTS: Of the sample, 30% had OH: the prevalence of systolic OH 1 minute and 3 minutes after standing up was 22% and 19%, respectively; that of diastolic OH 1 minute and 3 minutes after standing up was 6% for each. No differences in the occurrence of nonvascular deaths were found according to any of these definitions. By Cox multivariate regression analysis, the hazard ratio of vascular death associated with a diastolic BP reduction of 1 mm Hg 1 minute after standing up was 1.02 (P=.03), adjusted for systolic BP postural changes at 1 and 3 minutes and a diastolic BP change at 3 minutes. Adjusted for other significant factors associated with vascular death, the hazard ratio for vascular death associated with diastolic OH 1 minute after standing up was 2.04 (95% confidence interval, 1.01-4.15). The corresponding hazard ratio for systolic OH 3 minutes after standing up was 1.69 (95% confidence interval, 1.02-2.80). Using a cutoff point of 7 mm Hg or greater for a diastolic BP change 1 minute after standing up, the hazard ratio for vascular death was highest: 2.20 (95% confidence interval, 1.23-3.93). By logistic regression analysis, the baseline associates of diastolic OH 1 minute after standing up were dizziness when turning the neck (odds ratio [OR], 2.44), the use of a calcium antagonist (OR, 2.31), the use of a diuretic medication (OR, 2.29), a high systolic BP (OR, 2.23), and a low body mass index (OR, 2.26). The baseline associates of systolic OH 3 minutes after standing up were male sex (OR, 1.52), diabetes mellitus (OR, 1.92), a high systolic BP (OR, 2.91), and a low body mass index (OR, 1.68).
CONCLUSIONS: The presence of diastolic OH 1 minute and systolic OH 3 minutes after standing up predict vascular death in older persons. They differ from each other in their prevalence and in several associates, suggesting different pathophysiologic backgrounds. Clinicians should prescribe vasodilating and volume-depleting medications with caution for elderly persons with diastolic OH 1 minute after standing up. Appropriate treatment of hypertension might be the best means to manage the different types of OH with poor vascular prognoses.
Arch Intern Med. 1999 Feb 8;159(3):273-80. doi: 10.1001/archinte.159.3...

ミドドリン内服による、起立時の血圧への影響

ミドドリン内服は、プラセボに比べ、起立時の血圧上昇を来す。
出典
imgimg
1: Efficacy of midodrine vs placebo in neurogenic orthostatic hypotension. A randomized, double-blind multicenter study. Midodrine Study Group.
著者: Low PA, Gilden JL, Freeman R, Sheng KN, McElligott MA.
雑誌名: JAMA. 1997 Apr 2;277(13):1046-51.
Abstract/Text: OBJECTIVE: To evaluate the efficacy of a 10-mg dose of midodrine 3 times per day in improving blood pressure (BP) and ameliorating symptoms of orthostatic hypotension in patients with neurogenic orthostatic hypotension. Midodrine hydrochloride, an alpha-agonist, could improve orthostatic BP by increasing vasomotor and venomotor tone.
DESIGN/METHODS: A total of 171 patients with orthostatic hypotension participated in a multicenter, randomized, placebo-controlled study. They were randomized to a 10-mg dose of midodrine or placebo 3 times per day in a 6-week study, comprising single-blind run-in (at week 1) and washout at weeks 5 and 6, with an intervening double-blind period (weeks 2 to 4).
SETTING: Twenty-five centers, with most patients evaluated in referral centers.
MAIN OUTCOME MEASURES: The primary end points were improvement in standing systolic BP, symptoms of lightheadedness, and a global symptom relief score (by the investigator and patient separately).
RESULTS: Nine patients were not evaluable because of noncompliance or taking concomitant vasoactive medications (3 in the midodrine group, 6 in the placebo group). In the evaluable patients, midodrine resulted in improvements in standing systolic BP at all time points (P<.001 at visits 2, 3, 4, and 5), in reported symptoms by the end of the second week of treatment (P=.001), and in the global symptom relief score rated by both the patient (P=.03) and the investigator (P<.001). There was no effect by center, severity of orthostatic hypotension, use of fludrocortisone or compression garments, or diagnosis. The main adverse effects were those of pilomotor reactions, urinary retention, and supine hypertension.
CONCLUSIONS: Midodrine is efficacious and safe in the treatment of neurogenic orthostatic hypotension.
JAMA. 1997 Apr 2;277(13):1046-51.

起立性低血圧の診断のためのアルゴリズム

起立性低血圧を疑う症状がみられた場合、まず起立試験を行い診断を進める。
出典
imgimg
1: Orthostatic hypotension.
著者: Bradley JG, Davis KA.
雑誌名: Am Fam Physician. 2003 Dec 15;68(12):2393-8.
Abstract/Text: Orthostatic hypotension is a physical finding defined by the American Autonomic Society and the American Academy of Neurology as a systolic blood pressure decrease of at least 20 mm Hg or a diastolic blood pressure decrease of at least 10 mm Hg within three minutes of standing. The condition, which may be symptomatic or asymptomatic, is encountered commonly in family medicine. In healthy persons, muscle contraction increases venous return of blood to the heart through one-way valves that prevent blood from pooling in dependent parts of the body. The autonomic nervous system responds to changes in position by constricting veins and arteries and increasing heart rate and cardiac contractility. When these mechanisms are faulty or if the patient is hypovolemic, orthostatic hypotension may occur. In persons with orthostatic hypotension, gravitational opposition to venous return causes a decrease in blood pressure and threatens cerebral ischemia. Several potential causes of orthostatic hypotension include medications; non-neurogenic causes such as impaired venous return, hypovolemia, and cardiac insufficiency; and neurogenic causes such as multisystem atrophy and diabetic neuropathy. Treatment generally is aimed at the underlying cause, and a variety of pharmacologic or nonpharmacologic treatments may relieve symptoms.
Am Fam Physician. 2003 Dec 15;68(12):2393-8.

起立性低血圧の治療アルゴリズム

出典
img
1: 著者提供