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CVS - HTN pathophys
HTN pathophysiology & Treatment
| Question | Answer |
|---|---|
| Define HTN | SBP > 140mmHg and DBP >90mmHg. Any condition requiring antihypertensive RX |
| Classification & Etiology of HTN | Essential- 90%. due to unknown cause. Secondary-Renovascular, Pheochromocytoma, Cushing’s syndrome, Primary aldosteronism, Coarctation of aorta, Obstructive sleep apnea, Parathyroid disease, Thyroid disease, Drugs |
| Drugs that causes HTN | Steroids & OCP but HRT ok, OTC - NSAIDS& Decongestants, Illicit -Cocaine, Alcohol, Liquirce (chewable tobacco), St. John’s wort, Erythropoietin, Cyclosporine, tacrolimus, TCA, Venlafaxine, MAOI |
| Hemodynamic definition of HTN | BP = CO x TPR ie, Blood pressure = (stroke volume × heart rate) × peripheral resistance. stroke volume (SV) is determined by venous return (VR), end diastolic volume and cardiac contractility. CO= Volume / mit, CI= co/m2 or body surface area, Stro |
| Pathophysiology | Increased sympathetic activity, Overproduction of sodium retaining hormones (ANG II and aldosterone), Overproduction of vasoconstrictors ( ANG II, endothelin-1), Underproduction of vasodilators(ex. NO, prostacyclin, & natriuretic peptide). |
| Vasoconstriction caused by | increased O2, sympathetic, Angio 2, Vasopresin, Endothelin, Ecosanoids (PGF2, TXA2, Leukotriens) cold. decreased CO2. |
| Vasodilation is caused by. remember BNP increased in fluid overload/ increased preload and measured in cardiogenic shock | decreased O2, Sympathetic flow. Increased CO2, Nitric oxide, Ecosanoids (PGE2,PGI2), Histamin, Natriutetic peptide(ANP and BNP), Heat. |
| Define Mean arterial pressure (MAP) know the normal value (90-110) & target value (>65) | average pressure throughout the cardiac cycle of contraction. During cardiac cycle 2/3 of the time is spent in diastole and 1/3 in systole. Estimate of MAP: MAP=1/3(SBP)+2/3(DBP).CO x SVR or after load. Low MAP show hypoperfusion of organ. |
| Pulse pressure | difference between SBP and DBP. indicator of arterial wall tension/ arterial “stiffness” (arteriosclerosis and/or atherosclerosis). can predict cardiovascular risk (isolated systolic hypertension). |
| Short term regulation of BP | 1.Baroreceptor-Strech receptor- in^adr & decre. ACH. 2.Chemoreceptor ( decre. O2 & PH, Incre. CO2,de^ BP) - In^ sympathy & decre.ACH to in^ BP. 3.adrenal medulla- in^ sympathy. 4.CNS ischemia - decre. O2 few min- vasomotor stimulation - in^ adr |
| Long term regulation of BP | 1.Renin angio alodosterone system. 2.Vasopressin ADH. 3.fluid shift. 4.Natriuretic peptide ANP & BNP ( level of BNP shows fluid overload in HF). 5.Stress relaxation. |
| CVD Risk Factors - Framingham CV risk score 10% or more | Hypertension, Cigarette smoking, Obesity, Physical inactivity, Dyslipidemia, DM, Microalbuminuria or estimated GFR <60 ml/min, Age (older than 55 for men, 65 for women), Family history of premature CVD (men under age 55 or women under age 65) |
| Diagnosis | 2 or more properly measured BP readings from 2 or more clinical encounters. rest - 5 min. No caffeine or tobacco within prior 30 min. Arm bared and supported at heart level. cuff size appropriate. rpt after 2 min if more than 5 mmHg differ. |
| Symptoms | Asymptomatic. Signs/symptoms of Target organ damage- 1.Brain- TIA, stroke, 2.Eye- retinopathy , 3. Heart-CHF,LVH, CAD,angina, MI, 4.Kidney- CKD, 5. Peripheral vasculature- PAD. |
| Goals of therapy and Goal BP | reduce EOD.JNC 8<140/90- age < 60 years or DM or CKD. <150/90 for age ≥ 60 years. <140/80 mmHg for DM (ADA ). <130/80 mmHg for DM,CKD, CAD(Framingham)score >10%). <120/80 mmHg LVH -AHA. <140/90 CKD no protetin urea. <130/80 with protein - KDIEGO. |
| Treatment - pharmacologic & non pharmacologic | Life style modification, Antihypertensive RX. |
| Life style modification | Weight reduction, Reduce dietary fat and cholesterol, DASH diet, Reduce dietary Na- No more than 1.5gm Na in severe restriction ( normal<2.3gm Na) or 6gm NaCl per day) Increase aerobic exercise, Limit EtOH. |
| Drug Therapy - initial | Initial Therapy-Use of lifestyle modifications, thiazide diuretics in non–African American patient, CCBs /thiazide diuretics in African American, ACEIs or ARBs if CKD. |
| Drug Therapy - if not controlled by initial | Aldosteron Antagonist, Beta blockers, direct vasodilators, α1-receptor antagonists, central α2-receptor agonists, and postganglionic adrenergic neuron blockers,direct renin inhibitors |
| Hypertensive Emergecy | Severe elevation in BP > 180/120 with acute TOD . Treat initially with IV agents to decre. MAP by 25% with in min to hr. and 160/100 in 2-6 hr. goal BP in 1-2 days. |
| Hypertensive Urgency | Severe elevation in BP without acute TOD. immediate lowering of BP not required. treated outpatient with PO combination- AVOID nifedipine SL. Onset of action 15-30 min peak 2-3 hr. |