Alt_CV_Fcn_I_Class_Notes PDF - Cardiovascular Function

NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Hypertension Classification of Blood Pressure Category SBP (mmHg) DBP (mmHg) Normal...

NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Hypertension Classification of Blood Pressure Category SBP (mmHg) DBP (mmHg) Normal < 120 and < 80 Elevated 120-129 and < 80 Hypertension, Stage 1 130-139 or 80-89 Hypertension, Stage 2 > 140 or > 90 From the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults Pathophysiology Review of arterial blood pressure regulation Sympathetic nervous system stimulation (effects of norepinephrine & epinephrine) Alpha-1 adrenergic receptors: vasoconstriction of systemic arteries/arterioles Beta-1 adrenergic receptors: increased HR; increased strength of myocardial contraction à increased SV Other hormones that increase blood pressure Antidiuretic hormone: increased water reabsorption by kidneys à increased BV Thyroid hormone and cortisol: increased responsiveness to catecholamines 1  NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Renin-angiotensin-aldosterone system (RAAS) Summary of effects on blood pressure Angiotensin II is a potent arterial vasoconstrictor Aldosterone stimulates Na+ and water reabsorption (retention) in the kidneys 2  NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Proposed mechanisms for the development of hypertension i.e., possible contributing factors that result from genetic-environmental interactions Increased sympathetic nervous system activity à increased secretion of catecholamines and/or increased receptor reactivity Over-expression of the RAAS (or individual hormones from the RAAS) leads to vasoconstriction and Na+/H2O retention Mutations in genes that code for proteins in the renal tubules causing inappropriate Na+ reabsorption Decrease in the production of vasodilators (NO/ERDF, Pg, etc) Hemodynamic changes/consequences Increase in SVR with normal CO Increased left ventricular afterload Turbulence of blood causes shear stresses on vascular endothelium Vascular remodeling Increased levels of angiotensin II causes hypertrophy, hyperplasia and reorganization of vascular smooth muscle leading to a narrowed lumen Degenerative changes in the arterial wall are also seen 3  NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Risk Factors Genetic predisposition/family history Estimated to be a contributing factor in ~30-40% of cases (see What’s New box on p. 1063) Black race Genetic and environmental factors Older age Reduced arterial compliance + co-morbidities that cause secondary HTN Dietary factors High sodium (RDA = 2300 mg/day, 1500 mg/day for those at risk for HTN) Risk factor when combined with genetic predisposition or kidney disease Low potassium, magnesium, or calcium Tobacco use Causes impairment of endothelial function, vasoconstriction, atherosclerosis Alcohol Risk increases with > 3 drinks/day; low-moderate intake a risk factor for black men Obesity Adipose cells release leptin that stimulates the SNS and causes Na+ reabsorption by kidneys 4  NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Clinical Consequences of Uncontrolled Hypertension Atherosclerosis Abnormal thickening and hardening of the arterial wall Examples Coronary artery disease leading to myocardial ischemia/infarction Peripheral artery disease Cerebrovascular ischemia/ischemic stroke Heart failure Primarily left ventricular failure of a diastolic nature Chronic kidney disease Progressive loss of renal function over time Aneurysm A dilation or bulge of a blood vessel wall Examples Cerebral aneurysm leading to hemorrhagic stroke Aortic aneurysm Ocular changes Microvascular changes cause retinal injury Metabolic syndrome Insulin resistance caused by increased levels of angiotensin and epinephrine 5  NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Dyslipidemia Abnormal levels of lipids and/or lipoproteins in the blood Types of Lipids Triglycerides Ester of glycerol and fatty acids. The liver can synthesize triglycerides from glucose. In food products most oils and fats are made of triglycerides (saturated or unsaturated). Cholesterol Lipid that serves as a component of cell membranes and is required for the synthesis of steroid hormones, bile, vitamin D, etc… Types of Lipoproteins Chylomicrons Triglycerides, phospholipids, and cholesterol particle that transports dietary lipids from the small intestine to other regions of the body Very-low-density lipoproteins (VLDL) Transport endogenous triglycerides and cholesterol to the tissues Intermediate-density lipoprotein (IDL) Degraded cholesterol-rich VLDL, used to form LDL Low-density lipoproteins (LDL) Transport endogenous cholesterol in the plasma to the tissues High-density lipoproteins (HDL) Transport cholesterol and other lipids from the tissues to the liver to be metabolized 6  NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Risk Factors Genetic predisposition (familial dyslipidemia) At least 6 known gene mutations Dietary factors High cholesterol (red meat, full fat dairy products) Saturated fats (animal products) Tran fats (margarine, commercial baked goods) Obesity (BMI > 30) Visceral adipose tissue produces signaling molecules that promote insulin resistance, thus increasing LDL and VLDL Lack of Exercise Exercise increases HDLs Hyperinsulinemia/diabetes mellitus Hyperglycemia increases LDL and reduces HDL 7  NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Physiology of LDL Production and Metabolism Significance: Understanding the mechanisms of lipid lowering medications and the pathophysiology of atherosclerosis First step of cholesterol production requires the enzyme HMG-CoA reductase There are approximately 36 more biochemical steps involved in the production of cholesterol (many other enzymes involved) In the hepatocytes, cholesterol and varying amount of other lipids bind to an apolipoprotein to form VLDL VLDL is excreted into the bloodstream by exocytosis, then converted to IDL and eventually LDL. LDL is taken up into the cytoplasm of cells in the peripheral tissues (or back into the liver). To uptake LDL into its cytoplasm a cell must have (or synthesize) LDL-receptors Laboratory Evaluation Elevated LDL-C and/or VLDL Low HDL-C Elevated cholesterol Elevated triglycerides Considerations There can be marked day to day fluctuations, therefore, the client should fast for at least 12 hours prior to having blood drawn (water is allowed) No alcohol intake for at least 24 hours prior to test 8  NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Atherosclerosis Chronic disease of the arteries involving abnormal thickening and hardening of the blood vessel wall Causes Endothelial injury & Dyslipidemia Risk Factors for Endothelial Injury Hypertension Tobacco use Diabetes mellitus Infection Autoimmune diseases/immune reactions Hyperhomocysteinemia 9  NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Pathophysiology 10  NURS 7053 - Advanced Pathophysiology I for DNP Students Alterations of Cardiovascular Function I - Class Notes Laboratory Evaluation Evidence of dyslipidemia Total Cholesterol: healthy levels are less than 200 mg/dL Triglycerides: healthy levels are less than 150 mg/dL Lipoproteins HDL: healthy levels are greater than 40 mg/dL (as high as possible) LDL: healthy levels are less than 130 mg/dL (for those at low risk) Evidence of atherosclerosis Elevated high sensitivity C-reactive protein (hs-CRP): Predictor of atherosclerosis, hypertension, MI, and other cardiovascular disease Considerations hs-CRP can be used to guide lipid lowering therapy CRP is a general indication of inflammation Other Fasting glucose/HbA1c 11