Hypertension Pathophysiology PDF

10/17/23, 4:04 PM Realizeit for Student Hypertension Pathophysiology Gerontologic Considerations Structural and functional changes in the heart, blood vessels, and kidneys contribute to increases in blood pressure that occur with aging. These changes include accumulation of atherosclerotic plaque,...

10/17/23, 4:04 PM Realizeit for Student Hypertension Pathophysiology Gerontologic Considerations Structural and functional changes in the heart, blood vessels, and kidneys contribute to increases in blood pressure that occur with aging. These changes include accumulation of atherosclerotic plaque, fragmentation of arterial elastins, increased collagen deposits, impaired vasodilation, and renal dysfunction. The result of these changes is decreased elasticity or stiffening of the major blood vessels, particularly the aorta, and volume expansion (Eliopoulos, 2018; Fajemiroye, da Cunha, Saavedra-Rodríguez, et al., 2018). Hence, both SBP and DBP increase linearly up to the sixth decade of life. At that time, among most adults, DBP gradually decreases while SBP continues to rise. Thus, isolated systolic hypertension is the predominant form of hypertension in older people (Whelton et al., 2017). Results from randomized controlled studies have demonstrated that lowering blood pressure in older adults with isolated systolic hypertension is effective in reducing the incidence of adverse cardiovascular events and death (Whelton et al., 2017). https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IWsgl87YCND5MlxcaDR%2bIXwVK92JaTnVop0r%2bp7eT… 1/8 10/17/23, 4:04 PM Realizeit for Student https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IWsgl87YCND5MlxcaDR%2bIXwVK92JaTnVop0r%2bp7eT… 2/8 10/17/23, 4:04 PM Realizeit for Student Clinical Manifestations Physical examination may reveal no abnormalities other than elevated blood pressure. People with hypertension may be asymptomatic and remain so for many years. Hypertension is known as the “silent killer” because it typically has no warning signs or symptoms, and many people do not know they have it. However, when specific signs and symptoms appear, they usually indicate vascular damage, with specific manifestations related to the organs served by the involved vessels. These specific manifestations of pathophysiologic changes in various organs as a consequence of hypertension are referred to as target organ damage. Retinal changes such as hemorrhages, exudates (fluid accumulation), arteriolar narrowing, and cotton-wool spots (small infarctions) may occur. In severe hypertension, papilledema (swelling of the optic disc) may be seen (Weber & Kelley, 2018). Coronary artery disease with angina and myocardial infarction (MI) are common consequences of hypertension. LVH occurs in response to the increased workload placed on the ventricle as it contracts against higher systemic pressure. When heart damage is extensive, heart failure follows. Pathologic changes in the kidneys (indicated by increased blood urea nitrogen [BUN] and serum creatinine levels) may manifest as nocturia. Cerebrovascular involvement may lead to a transient ischemic attack (TIA) or https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IWsgl87YCND5MlxcaDR%2bIXwVK92JaTnVop0r%2bp7eT… 3/8 10/17/23, 4:04 PM Realizeit for Student stroke, manifested by alterations in vision or speech, dizziness, weakness, a sudden fall, or transient or permanent hemiplegia (paralysis on one side). Cerebral infarctions account for most of the strokes in patients with hypertension (Norris, 2019). Assessment and Diagnostic Findings The first step of diagnosis is an accurate blood pressure measurement (see Chart 27-3 for an overview of appropriate BP measurement equipment, instructions, and interpretation for both the patient and the clinician). It is important to use an average of at least two blood pressure readings on at least two occasions to confirm the diagnosis of hypertension for most patients. The notable exception is when a patient’s average BP is greater than or equal to 160/100 mm Hg, confirmed by at least two accurate readings on one occasion (see later discussion) (Muntner, Shimbo, Carey, et al., 2019; Whelton et al., 2017). Blood pressure measurement within a clinical setting is often not an accurate reading; therefore, home blood pressure measurement (HBPM) or ambulatory blood pressure measurement (ABPM) are considered more accurate reflections of the blood pressure status. HBPM and ABPM are used not only to confirm the diagnosis of hypertension in most cases, but also to evaluate whether success has been achieved with treatments, such as lifestyle modifications and prescription medications (see later discussion) (Whelton et al., 2017). Utilizing HBPM and ABPM measurements have led to recognizing other manifestations of blood pressure. Examples of these alternative manifestations of hypertension include masked hypertension and white coat hypertension. Patients with masked hypertension exhibit elevated blood pressure at levels typically consistent with hypertension in settings outside the hospital or clinic, while their blood pressure is seemingly normal in health care settings. In contrast, patients with white coat hypertension have blood pressure readings that would suggest a diagnosis of hypertension when they are in health care settings (e.g., clinics), but are within the normal ranges in other settings. If untreated, the patient with masked hypertension can go on to experience adverse cardiovascular events (e.g., MI, strokes) and mortality. On the other hand, the patient with white coat hypertension may receive treatment that is not warranted (Cohen, Lotito, Trivedi, et al., 2019). A thorough health history and physical examination are necessary to ensure successful diagnosis and treatment. The onset of high blood pressure and the patient’s health history can be used to determine whether the patient might have primary hypertension or secondary hypertension (see Chart 27-2). Abnormal findings from the physical examination could suggest either target organ damage or secondary hypertension. The physical examination should include palpation of all peripheral pulses. Absent, weak, or delayed femoral pulses could suggest coarctation of the aorta or severe peripheral vascular disease. The neck should be examined for carotid bruits, distended veins, or an enlarged https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IWsgl87YCND5MlxcaDR%2bIXwVK92JaTnVop0r%2bp7eT… 4/8 10/17/23, 4:04 PM Realizeit for Student thyroid gland. The upper abdomen should be auscultated for the presence of a renal artery bruit that could be suggestive of renal artery stenosis. A careful cardiac examination is also needed to evaluate for signs of LVH. LVH signs include displacement of the apex, a sustained and enlarged apical impulse, and the presence of an S4 cardiac sound (Weber & Kelley, 2018). Occasionally, signs of hypertension can be discovered during a fundoscopic eye examination manifested as hypertensive retinopathy (e.g., retinal hemorrhages, microaneurysms, cotton-wool spots, papilledema); these findings are associated with an increased cardiovascular risk (e.g., stroke). Acute or chronic ocular changes can be the initial finding in asymptomatic patients and typically require a referral to an ophthalmologist. Long-standing, untreated hypertension can cause heart failure, CKD (elevated BUN and creatinine), and increased risk for cerebrovascular disease (e.g., TIAs, strokes) (Weber & Kelley, 2018). Laboratory tests are also performed to assess for possible target organ damage and to screen for primary hypertension or secondary hypertension. These typically include urinalysis, blood chemistry (i.e., analysis of sodium, potassium, creatinine, fasting glucose, cholesterol levels), and a 12-lead electrocardiogram. LVH can be assessed by echocardiography. Renal damage may be suggested by elevations in BUN and creatinine levels or by microalbuminuria or macroalbuminuria. Additional studies, such as creatinine clearance, renin level, urine tests, and 24-hour urine protein, may be performed. Optional testing may include uric acid and urine albumin to creatinine ratio (Whelton et al., 2017). Medical Management The goal of hypertension treatment is to prevent complications (i.e., target organ damage) and death by maintaining a blood pressure lower than 130/80 mm Hg. Findings from a systematic review and meta-analysis demonstrated that hypertension treatment that effectively achieves the aim of BP control to normal levels is associated with lower mortality and lower rates of CVD (Brunstrom & Carlberg, 2018). The optimal treatment plan is one that is inexpensive, simple, and causes the least possible disruption in the patient’s life. The ACC/AHA Guidelines (Whelton et al., 2017) have developed a series of recommendations for prevention, treatment, and management of hypertension. In addition, these guidelines specify that a diagnosis of hypertension must be made based on accurate blood pressure measurements. As noted previously, an average of at least two blood pressure readings on at least two occasions should be used to confirm the diagnosis of hypertension for most patients. After having the BP measured to screen for hypertension, a patient not previously diagnosed with hypertension and with a normal BP (i.e., SBP less than 120 mm Hg and DBP less than 80 mm Hg) can be advised to have the BP reevaluated in 1 year. A patient without a prior diagnosis of hypertension with an elevated BP (i.e., SBP 120 to 129 mm Hg and DBP less than 80 mm Hg) should be advised to follow up with additional BP readings within 3 to 6 months. A patient with a BP that could be consistent with hypertension; that is, https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IWsgl87YCND5MlxcaDR%2bIXwVK92JaTnVop0r%2bp7eT… 5/8 10/17/23, 4:04 PM Realizeit for Student with an SBP greater than or equal to 130 mm Hg or a DBP greater than or equal to 80 mm Hg should follow-up with additional BP readings within 1 month’s time to either confirm or rule out the diagnosis (Muntner et al., 2019; Whelton et al., 2017). So that patients with suspected white coat hypertension or masked hypertension may be accurately diagnosed, blood pressure readings should be based on HBPM or ABPM. Patients not instructed to follow up with additional BP readings to confirm a diagnosis of hypertension are patients with average BP readings greater than or equal to 160/100 mm Hg on one occasion; these patients are diagnosed with hypertension and begin treatment with antihypertensive medications (Muntner et al., 2019; Whelton et al., 2017). All patients who report lifestyle choices that may put them at risk for hypertension should be counseled to adopt lifestyle changes, as appropriate. These lifestyle changes could include weight loss, dietary changes, physical activity modifications, decreased alcohol consumption, and smoking cessation (Table 27-2). In particular, the Dietary Approach to Stop Hypertension (DASH) diet has been one of the most effective diets in lowering BP; if used in conjunction with weight loss, this diet can lower SBP by 11 to 16 mm Hg (Campbell, 2017) (Table 27-3). In addition to this dietary advice, patients should be counseled to incorporate a low sodium (less than 2 g/day), high potassium (3500 to 5000 mg/day) diet; this dietary combination is more effective than following either a lone low sodium or high potassium diet (Perez & Chang, 2014). A high potassium diet must be avoided in patients with CKD, however. Patients suspected to have secondary hypertension must be accurately screened and the disorder that caused the high blood pressure must be properly treated in order to bring the patient’s blood pressure into normal parameters (see Chart 27-2). The recommended treatment for patients with elevated blood pressure but who are not diagnosed with hypertension is lifestyle changes, not antihypertensive medications, with follow-up in 3 to 6 months, as noted previously, to not only reevaluate the blood pressure but to see if it has responded positively to lifestyle modifications (Whelton et al., 2017). The primary provider is advised by the ACC/AHA Guidelines (Whelton et al., 2017) to screen the patient diagnosed with Stage 1 hypertension for risk of having adverse cardiac events (e.g., stroke, MI) within the next 10 years by using the online ASCVD Risk Estimator Plus. This tool is published by the ACC and is free to use (links to this tool are provided in the Resources section at the end of this module). This tool screens patients based on factors that include blood pressure readings, age, gender, lipid panel results, use of medications, smoking status, and whether or not they have concomitant diabetes. The risk of having an adverse cardiac event is then determined as low, borderline, or high. Those patients with a score of 10 or higher (consistent with mid-borderline risk) should be prescribed an antihypertensive medication, as should any patient diagnosed with stage 2 hypertension. All patients should be advised to institute relevant lifestyle changes, regardless of stage and use of antihypertensive medications. https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IWsgl87YCND5MlxcaDR%2bIXwVK92JaTnVop0r%2bp7eT… 6/8 10/17/23, 4:04 PM Realizeit for Student https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IWsgl87YCND5MlxcaDR%2bIXwVK92JaTnVop0r%2bp7eT… 7/8 10/17/23, 4:04 PM Realizeit for Student https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IWsgl87YCND5MlxcaDR%2bIXwVK92JaTnVop0r%2bp7eT… 8/8