Orthostatic Hypotension in the Elderly Dan Michael Sodano, MD, FACC, RPVI BMG Cardiology

Epidemiology Occurs in upwards of 30% of the elderly Typically not found in the healthy elderly and should not be expected in the healthy Associated with falls, syncope, and hospitalization Seen in 68% of those discharged from acute geriatric ward Significant percentage of those with asymptomatic orthostatic hypotension – approaches 33% of individuals

Normal Response to Standing There may be a slight reduction of systolic blood pressure Can be upwards of 20% reduction in cardiac output Diastolic blood pressure may be unchanged to slightly increased There may be 5-20 beats per minute increase in heart rate, which can be blunted in the elderly

Control of Blood Pressure Baroreceptor reflex Found in the carotid sinus and aortic arch Sensitive to changes in pressure Decrease in pressure leads to less stretch which then sends signal to medulla oblongata leading to stimulation of sympathetic nervous system which then activates vasoconstriction Increase in pressure leads to more stretch which then sends signal to medulla oblongata leading to stimulation of parasympathetic nervous system (by inhibiting sympathetic activation) which then activates vasodilation of arterioles and decreases cardiac stimulation and HR which serves to lower blood pressure by lowering cardiac output

Control of Blood Pressure Chemoreceptor reflex Found in the medulla oblongata Primarily involved in regulation of respiration and ventilation, but in extreme circumstances, can elevate BP Decrease in PO2, increase in CO2, increase in pH Leads to stimulation of vasomotor center which serves to: - increase HR - increase contractility - increase vasoconstriction - All serves to increase blood flow to heart and lungs

Regulation of Falling BP Baroreceptors are inhibited Decreased impulses to the brain Decreased parasympathetic activity and increased sympathetic activity Heart: Increased HR and contractility Vessels: Increased vasoconstriction Adrenal gland: Increased release of norepinephrine/epinephrine All serve to increase contractility and HR End result is increase in mean arterial pressure

Definition of Orthostatic Hypotension Reduction of systolic blood pressure of 20 mmHg and/or reduction of diastolic blood pressure of 10 mmHg within 3 minutes of standing Change in heart rate or presence of symptoms are not included in the definition Head up tilt at 60° can be used in place of standing

Risk Factors of Orthostatic Hypotension in the Elderly Cardiac diseases such as severe AS, cardiomyopathy, severe restrictive cardiomyopathy CNS diseases (very important) Chronic hypertension Venous insufficiency Antihypertensives Diabetes mellitus Alcoholism Amyloidosis Dementia

Presentation of Orthostatic Hypotension Important to note that many patients exhibit atypical symptoms such as: Backache Headache Neck pain Shortness of breath Chest pain Seizures Fatigue Severely reduced blood flow to heart and brain  angina, TIA Typical symptoms predominant and include: Postural dizziness Postural syncope/presyncope

Neurogenic Causes of Orthostatic Hypotension Neurogenic causes – autonomic failure due to idiopathic central and peripheral neurodegenerative causes Primary causes of autonomic failure Parkinson’s disease Lewy body dementia Pure autonomic failure Multiple system atrophy (Shy-Drager syndrome) Secondary causes of autonomic failure Diabetes mellitus Primary amyloidosis

Non-neurogenic Causes of Orthostatic Hypotension Age-related – related to comorbidities, medications, hospitalizations, illness Cardiac pump failure Extensive myocardial infarction Constrictive pericarditis Aortic stenosis Significant tachyarrhythmias or bradyarrhythmias Reduced intravascular volume Metabolic Adrenocortical insufficiency Hypoaldosteronism Pheochromocytoma Venous pooling - Prolonged recumbency, standing, hot baths/showers, hot environment

Medications Associated with Orthostatic Hypotension Diuretics Vasodilators – hydralazine, nitrates, dihydropyridine CCBs Alpha blockers Beta blockers CNS sedatives Tricyclic antidepressants Phenothiazines Alcohol

Head-up Tilt-Table Testing

Pathogenesis Impairment of the baroreceptor reflex Changes in baroreceptor reflex arc: heart rate response, vascular compliance, vasopressin release, renin-angiotensin and renal concentrating response Depressed myocardial contractility and vascular responsiveness Impaired autonomic reflex arc (afferent, central, or efferent)

Bedside Evaluation of Orthostatic Hypotension History Physical examination Look for signs of volume depletion Parkinsonian features Neuro exam Foot exam looking for evidence of diabetic peripheral neuropathy Good cardiac examination looking for murmurs, JVD, heart size Orthostatic vital signs (after 1, 3, and 5 minutes)

Ancillary Methods to Assist with Evaluation ECG: looking for signs of MI, bradyarrhythmias, tachyarrhythmias Echocardiogram: evaluating for cardiomyopathy, aortic stenosis Head-up Tilt Table Testing Laboratory analysis BUN/Cr Na and K Glucose Cortisol and Aldosterone when indicated Catecholamines when indicated

Non-pharmacologic Treatment Acceptance Maintaining good hydration (at least 2 L/day) Increasing salt intake where appropriate Avoidance of deconditioning Gradual rise from seated positions, after meals, or defecation/urination Small and frequent meals Avoidance of prolonged standing or hot/humid environments Physical counter-maneuvers (leg crossing, muscle tensing, squatting) whilst standing Elastic stockings

Pharmacologic Treatments Midodrine - α agonist Droxidopa – norepinephrine precursor Pyridostigmine – acetylcholinesterase inhibitor (for neurogenic orthostatic hypotension only) Fludrocortisone – mineralocorticoid leading to volume expansion Desmopressin – vasopressin analogue and also expands volume