[Music] welcome to this presentation on hypertension hypertension or high blood pressure is a chronic medical condition in which the blood pressure in the arteries is elevated it is a major risk factor for coronary artery disease stroke heart failure renal disease and peripheral vascular disease blood pressure is noted by two measurements reflecting the systolic and diastolic pressure at rest the long-term risks of vascular complications due to sustained high blood sugar blood pressure increase progressively high blood pressure is most widely accepted as diastolic pressure greater than 90 millimeters of mercury and systolic blood pressure higher than 140 millimeters of mercury pre-hypertensive values are 80 to 99 millimeters of mercury diastolic and 120 139 millimeter mercury systolic hypertension is often known as a silent killer as patients can remain asymptomatic for years with sustained high blood pressure values until complications arise the damage to vascular structures continues through this process blood pressure is a product of cardiac output and total peripheral resistance in its it is worth mentioning again the formula for cardiac output four factors play active roles in regulating blood pressure including heart rate blood vessel tone kidney and hormones this table shows criteria for high blood pressure values and normal blood pressure values this table further shows target values for blood pressure control note that normal pressure threshold for patients with diabetes or kidney disease is lower than not of other patients hypertension is classified as primary hypertension or secondary hypertension about 90 to 95 percent of cases are characterized as primary or essential hypertension which means high blood pressure with no obvious underlying medical cause or genetic factors this type of hypertension typically presents with patients after young adulthood and predominantly over 60 years of age and there are significant associations between hypertension and obesity insulin resistance and diabetes essential hypertension can arise from many potential origins or defects whether inherited or acquired that follows a typical pattern of increasing values proportional to increase in age secondary hypertension is attributable to identifiable conditions that affect the kidneys arteries heart or endocrine system these conditions can often be corrected to normalize blood pressure values the following factors may favor patients as having secondary hypertension younger age severity values onset is more abrupt associated signs and symptoms and family history of hypertension is sporadic and not first degree we will further detail each of the causes of secondary hypertension further in the lecture many systemic defects have been identified with essential hypertensive patients and we briefly summarize these abnormalities that potentially contribute to chronic bp elevation the heart can facilitate higher cardiac output due to overactivity of the sympathetic nervous system and blood vessels may contribute to peripheral vascular resistance by constricting in response to increased sympathetic activity or abnormal regulation a vascular tone the kidneys can retain excessive sodium and water to induce volume based hypertension elevated insulin levels can increase sympathetic activation obesity releases angiotensinogen to activate the rast system and metabolic syndrome represents a gathering of atherogenic risk factors that increase and include hypertension we'll continue the discussion of the regulation of systolic blood pressure by examining this image and the four systems that contribute to bp regulation you will notice beside each regulating factor an arrow and a down arrow the up arrow represents an increase in stimulatory effect and the down arrow represents an inhibitory effect in our body we have intrinsic mechanisms to maintain blood pressure and continuously monitor changes in arterial pressure and respond rapidly to extreme values the most important mechanism is the baroreceptor reflex which is found in the aortic arch walls and carotid sinuses the receptors will monitor pressure changes and will be stimulated by sensing changes in vessel ball stretch and will react by sending signals to the central nervous system as signals arrive at the central nervous system in the medulla barrel receptors will inhibit sympathetic nervous system outflow and excite parasympathetic effects together the convergence will decline peripheral vascular resistance and reduce cardiac output to lower arterial blood pressure back to baseline levels now let's discuss the underlying cause for secondary hypertension which arise from an identifiable cause and are often correctable exogenous causes include medications that can contribute to increase in blood pressure these include oral contraceptives estrogens glucorticoids cyclosporine erythro biotin sympathetomymetic drugs cocaine and ethanol kidney disease contributes to two leading causes of secondary hypertension that is renal parenchymal disease which leads to increased intravascular volume and renal artery stenosis calling reduced blood flow to kidneys and activating secretion of renin as previously discussed the renin angiotensin aldosterone system or brass is a hormone system that regulates blood pressure and water balance this image aids as a refresher to the functioning and process of the system and its ability to increase the volume of fluid in the body which also increases blood pressure other potential causes of secondary hypertension include a mechanical abnormality in origin correctation of the aorta as well as endocrine causes such as viochromocytoma cushion syndrome and thyroid abnormalities all contribute to a secondary cause of hypertension note that both hypothyroid and hyperthyroid may lead to significant hypertension hypertension will eventually lead to organ damage as we know asymptomatic patients generally do not present to physician until complications are arising from hypertension the degree and extent of the chronic hypertension will target specific organs the damage on organs is directly a result of the increased workload on the heart and arterial damage due to the effects of elevated pressures which will weaken arterial walls and accelerate arthroscorosis the following chart outlines target organ damage due to hypertension and its manifestations hypertension increases the risk of ischemic heart disease stroke peripheral vascular disease and other cardiovascular diseases such as heart failure aortic aneurysm diffuse atherosclerosis and pulmonary embolism hypertension is also a risk factor for cognitive impairment and dementia in chronic kidney disease other complications includes hypertensive retinopathy and hypertensive nephropathy if left untreated patients may die from any of these complications a hypersensitive crisis is hypertension with acute impairment of one or more organ systems due to severe elevation of blood pressure this type of acute presentation is typically caused by inadequate bp treatment as the situation's acute and rapid changes occur the organs most affected are the central nervous system cardiovascular system and or the renal system such impairment can result in irreversible organ damage as the dramatically rising bp will further increase blood volume and vasoconstriction in a hypertensive crisis the blood pressure should be slowly lowered over a period of minutes to hours with a hypertensive agent the first line of treatment for hypertension is lifestyle modifications the following guidelines will aid in hypertension reduction diet high in vegetables and fruit low fat dairy for the reduction of salt intake potassium reduction decreased alcohol consumption rate reduction to avoid obesity states regular aerobic exercise smoking cessation and relax their therapy all contribute to a balanced lifestyle and controlling blood pressure without any expensive medications or potential side effects if lifestyle modifications are ineffective in controlling hypertension medication will likely be prescribed the first line medication will be administered in sequence usually starting with diuretics there are four classes of commonly administered medications to treat hypertension diuretics some patholytics vasodilators and drugs that interfere with the ras system diuretics are the first choice for lowering blood pressure and their action is decreased circulating volume cardiac output and also decreased arterial pressure there are three types of diuretics thiazide diuretics potassium sparing diabetics and loop diuretics the sympatholytics such as beta blockers and alpha adrenergic agonists function to overall decrease cardiac output heart rate and mild decrease in contractility beta blockers also decrease release of renin to help reduce total peripheral resistance alpha-1 antagonists are really prescribed due to their side effects but their action is in reducing sympathetic outflow to the heart blood vessels and kidneys resulting in decreased total peripheral resistance via smooth muscle relaxation if a patient has contraindication to beta blockers peripheral vasodilators can be prescribed which include calcium channel blockers hydrolysis and minoxidil the action of vasodilators is to reduce calcium influx in cardiac and smooth muscle contraction resulting in reduced contractility and total peripheral resistance the final group of hypertension medications that interfere with the rast system are known as ace inhibitors and angiotensin receptor blockers or arbs ace inhibitors blockade the conversion of angiotensin 1 to angiotensin ii to reduce phase repressor effect of angiotensin ii and secretion of aldosterone this function is to decrease blood pressure as peripheral vascular resistance declines as well as sodium retention in the kidneys commonly a cough is a side effect of ace inhibitors and if not tolerated or there is an inadequate bp control angiotensin receptor blockers or arbs can be prescribed as an alternative for patients with diabetes or kidney diseases it is usually recommended to begin from ace inhibitors instead of beta blockers as inhibitors protect kidney function better this diagram shows the physiological effects of respective antihypertensive medications that takes us to the end of this presentation on hypertension