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Cards HTN Dx
Cardiology
Question | Answer |
---|---|
Goals of Diagnosing HTN | Detect & stage HTN severity; detect TOD; assessing overall CV risk; detect secondary causes of HTN |
HTN stats | 1 in 3 in US = HTN; 66 mil in US 20 yo & older; 95% are essential HTN; 2005 in US, direct & indirect cost of HTN = $59.7 Billion |
HTN pt awareness stats | 63% aware of the dx; only 45% receiving tx; 34% under ctrl using a threshold criterion of 140/90 |
Factors of essential HTN: | Genetic defect, inc dietary Na intake, intrinsic renal differences, stress, obesity, drug or substance abuse |
Primary HTN: other factors: | Variable plasma renin activity; variable symp n.s. response & catecholamines; insulin resistance & DM; inadequate dietary K+ & Ca+ ; resistant vessels |
Renal artery stenosis in HTN: MOA | Excessive renin release in response to decrease in renal blood flow & perfusion pressure |
Renal vascular HTN: 2 pathologic processes (resulting in stenosis) | 85% atherosclerosis of proximal renal arteries (pts usu also have CAD); 15% fibromuscular dysplasia (esp in F 15–50 yrs; genetic predisposition) |
Fibromuscular dysplasia (FMD) is characterized by: | fibrous thickening of the intima, media, or adventitia of the renal artery |
Congenital abnormality which results in narrowing of the aorta, usually in the ascending region, which increase PVR due to the stenosis | Coarctation of the Aorta |
Coarctation of the Aorta: incidence | Rare (1:10,000) & usually accompanies other abnormalities such as bicuspid aortic valve or Turner Syndrome |
Hyperaldosteronism: most common etiologies: | unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia |
If Pheochromocytoma undiagnosed: | Outpouring of catecholamines during unrelated surgical/ radiologic procedure can lead to severe, abrupt hypertensive crisis & mortality rate over 80% |
Obstructive sleep apnea & HTN | HTN = response to chronic, intermittent hypoxia during nocturnal apneic episodes |
HTN & chronic kidney dz: epidemiology | HTN is second most common cause of chronic kidney disease (> 25% of cases) |
Most easily recognized treatable risk factor for stroke, MI, CHF, peripheral vascular dz, aortic dissection, atrial fibrillation & end-stage kidney disease | HTN |
HTN in younger pts (< 50 yrs): Hemodynamic fault = | vasoconstriction at the level of the resistance arterioles |
Isolated systolic HTN: associated risks | BP of 160/60 (pulse pressure of 100 mmHg) carries 2x the risk of fatal coronary heart dz as 140/110 (pulse pressure of 30 mmHg) (PP = SBP – DBP) |
Diastolic BP age pattern | Peaks in the early 50’s, then declines for men and women (Systolic BP continues to rise for both throughout life) |
Resistant Hypertension | Defined as persistence of BP > 140/90 despite tx with full doses of 3 or more different classes of meds in rational combination (& including a diuretic); important to know pt is compliant |
4 Categories of Resistant HTN | Pseudoresistance; Inadequate medical regimen; Nonadherence or ingestion of pressor substances; secondary HTN |
Pseudoresistance: | Usually caused by white coat effect superimposed on chronic HTN that is well controlled with meds outside the office |
Resistant HTN: Inadequate medical regimen | Absence of appropriate diuretic; Renal fn impairment which affects drug clearance; monotherapy or inadequate dosing of meds |
Resistant HTN: Nonadherence or ingestion of pressor substances | a. Medication nonadherence; b. Lifestyle modification noncompliance; obesity, high salt diet, excessive alcohol intake; c. Habitual use of tobacco, cocaine, meth, phenylephrine or NSAIDS (cause renal Na+ retention) |
Resistant HTN: Secondary HTN: | If you’ve exhausted the first 3 categories, time to look for secondary cause of HTN |
Most commonly overlooked secondary causes of Resistant HTN: | Chronic kidney dz & primary aldosteronism |
Hypertensive Urgency | Severe elevation of BP; No evidence of progressive TOD; benefit from BP lowering in a few hrs; absence of raised intracranial pressure |
Hypertensive Emergency | Acute, severe elevation in BP; evidence of rapidly progressive TOD (eg, MI, pulmonary edema or renal failure); requires immediate, gradual reduction of BP (NOT to the normal range); always look for secondary causes |
Malignant Hypertension: | Type of Hypertensive Emergency; usually accompanied by other end organ damage |
Malignant Hypertension is most common in: | Young adults, prior renal dz, AA males, PG, or collagen vascular dz |
Dz w/ Compelling Indications for tight HTN ctrl | CHF; High Coronary Dz Risk; Chronic Kidney Dz; DM; Post-MI; Recurrent Stroke Prevention |
Fn of Angiotensin II | Stimulates release of Na+-retaining hormone aldosterone (adrenal corticol cells); amplifies vasoconstriction (systemic and renal) |
BP = | CO X PVR |
Essential HTN = | established primary HTN |
Hallmark of essential HTN = | elevated peripheral vascular resistance |
Variations in BP determined by: | variations in ECF volume, heart contractility, & vascular tone |
Def of HTN = repeated readings of: | SBP over 140 &/or DBP over 90 |
Evidence supports tx of high risk pts at lower threshold of: | of 130/80 mmHg. |
HTN: High risk groups include: | DM, chronic kidney dz, CV or Cerebrovascular dz, or LVH on EKG |
Factors of essential HTN affect: | ECF volume, heart contractility, or vascular tone |
HTN contributes to what % of M/F AA deaths? | 30% M & 20% F |
Most common secondary cause of HTN | Chronic renal dz (proteinuria, high creat) |
?% of pts w/ chronic renal dz have HTN | 85% |
Chronic renal dz & HTN: MOA | expanded plasma volume & peripheral vasoconstriction |
Renal artery stenosis prevalence in HTN pts | less than 2% |
HTN pts w/ renal artery stenosis: proportions | 75% unilateral stenosis; 25% bilateral |
Renal artery stenosis causes what % of medically refractory HTN? | 30% |
Catecholamine-producing large tumors of adrenals | Pheochromocytoma |
HTN & CPAP use for OSA | CPAP improves risk of developing HTN & CV dz |
HTN prevalence in DM pts | 75% of diabetics have HTN |
Aldosterone-like effect precipitates persistent HTN in: | Cushing Syndrome |
Leading cause of death worldwide | arterial HTN |
Using standard size cuff on obese pt: | Gives falsely elevated result |
Ambulatory BP monitor can detect: | Lack of nocturnal dip (assoc w/higher CVD risk) |
BP & substances | Avoid tobacco/caffeine 30 min prior; document if pt took meds |
Ambulatory BP monitor & TOD | Better TOD predictor than office measurements |
What symptom must be present for a dx of Malignant Hypertension? | Papilledema |
Most patients who develop HTN after 50 yrs have: | Isolated Systolic HTN |
Defn Isolated Systolic HTN | systolic BP over 140 mmHg with diastolic BP <90 mmHg |
Isolated Systolic HTN: hemodynamic fault = | decreased distensibility of the large conduit arteries |
Majority of uncontrolled HTN occurs among: | older pts with isolated systolic HTN. |
JNC8: SBP opinion | In pts over 50, SBP over 140 is a more important CVD risk than DBP |
Most common cause of Hypertensive Emergency | Acute CHF with pulm edema (37%) |
HTN eval labs | UA; serum Cr, glu, K+, Na+ ; Lipids (TC, trigs, HDL, LDL); 12-Lead EKG (LVH) |
HTN TOD | Neuro; Ophthalmologic; CV; Renal; Vascular |
Excessive Na+-K+ exchange which results in hypokalemia; associated with HTN | Hyperaldosteronism |
Hydralazine MOA: | Direct vasodilation of arterioles (with little effect on veins) with decreased systemic resistance |
Ca Channel Blockers = | Nifedipine, verapamil, diltiazem, amlodipine, felodipine |
Amlodipine MOA: | CCB without negative inotropic effects but with vascular smooth muscle relaxing activity |
Dash diet = | low in Na, fat; high in K+, fiber, calcium; lowers SBP 8-14 |
HTN BP goals (for nl, CAD, DM) | Nl: <140/90; DM or CKD: <130/80 |
HTN med choices: w/o CE | stage 1 thiazide, ACE/ARB, BB, CCB; stage 2: 2 drug combo (usu HCTZ + ACE etc) |
HTN med choices: w/ CE | thiazide: HF, CVD risk, DM; ARB: HF/DM; BB: any but CKD/stroke prevention; CCB: CVD risk/DM |
Hypertensive emergency etiology | fibrinoid necrosis of small arteries causes end organ damage (heart, brain, kidneys, eyes) |
Hypertensive emergency definitions | crisis >180/110; urgency DBP >130; emergency is EOD; malignant is papilledema |
Grossly elevated blood pressure esp. w/ signs of TOD | Malignant HTN, hypertensive crisis: tx sodium nitroprusside to rapidly lower BP |
HTN with idiopathic hypokalemia may be 2/2 = | hyperaldosteronism (check renin/ aldosterone level); usu 2/2 adenoma |
HTN & PG | OCP can increase BP (HRT does not); PG tx with methyldopa, BB, vasodilators (hydralazine) |
HTN urgency vs emergency | emergency: TOD, admit, IV tx; urgency no/stable TOD, observe 3-6 hr, PO tx (captopril, clonidine, or labetalol) |
Factors of essential HTN: | Genetic defect, inc dietary Na intake, intrinsic renal differences, stress, obesity, drug or substance abuse |
Renal artery stenosis in HTN: MOA | Excessive renin release in response to decrease in renal blood flow & perfusion pressure |
Renal vascular HTN: 2 pathologic processes (resulting in stenosis) | 85% atherosclerosis of proximal renal arteries (pts usu also have CAD); 15% fibromuscular dysplasia (esp in F 15–50 yrs; genetic predisposition) |
HTN & chronic kidney dz: epidemiology | HTN is second most common cause of chronic kidney disease (> 25% of cases) |
Isolated systolic HTN: associated risks | BP of 160/60 (pulse pressure of 100 mmHg) = 2x risk of fatal CHD as 140/110 (pulse pressure of 30 mmHg) (PP = SBP – DBP) |
Diastolic BP age pattern | Peaks in early 50s, then declines for men and women (SBP continues to rise for both thru life) |
Resistant Hypertension = | persistence of BP >140/90 despite tx w/full doses of 3 or more diff classes of meds in rational combo (& including a diuretic); important to know pt is compliant |
Most commonly overlooked secondary causes of Resistant HTN: | Chronic kidney dz & primary aldosteronism |
Hypertensive Urgency = | Severe elevation of BP; No evidence of progressive TOD; benefit from BP lowering in a few hrs; absence of raised intracranial pressure |
Hypertensive Emergency = | Acute, severe elevation in BP; sxs of rapidly progressive TOD (eg, MI, pulmo edema, ARF); req immed, gradual reduction of BP (NOT to normal range); look for secondary causes |
HTN: High risk groups include: | DM, chronic kidney dz, CV or Cerebrovascular dz, or LVH on EKG |
Factors of essential HTN affect: | ECF volume, heart contractility, or vascular tone |
Ambulatory BP monitor can detect: | Lack of nocturnal dip (assoc w/higher CVD risk) |
Most patients who develop HTN after 50 yrs have: | Isolated Systolic HTN: systolic BP >140 with diastolic <90 |
Most common cause of Hypertensive Emergency | Acute CHF with pulm edema (37%) |
Hyperaldosteronism: most common etiologies: | unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia |
If Pheochromocytoma undiagnosed: | Outpouring of catecholamines during unrelated surg/ radiologic procedure can lead to severe, abrupt hypertensive crisis & mortality rate over 80% |
Malignant Hypertension is most common in: | Young adults, prior renal dz, AA males, PG, or collagen vascular dz |
Normal angiotensin function | Renin promotes angiotensin I production -> ACE converts to angiotensin II -> vasoconstriction, aldosterone secretion (-> Na reabsorption & K secretion) -> higher BP |
Normal adrenergic function | Adrenergic stimulation -> stimulate beta 1 receptors (inc HR) -> increase BP; also stimulate alpha 1 receptors -> vasoconstriction |
HTN funduscopic exam: | may see AV nicking, narrowed arteries, copper / silver wiring of arterioles, hemorrhages, exudates, papilledema |
Cardiogenic shock = | SBP <90 (or 30 mmHg below baseline >30 min); sxs poor tissue perfusion, persistence of shock after correction of non-myocardial factors |
Cardiogenic shock: non-myocardial factors include: | 6 H's (hypovolemia, hypoxia, acidosis, etc), arrhythmias, MI & comps (valve dz, LV aneurysm, CM), myocarditis, LVOT obstruction (eg, AS) |
When to suspect RAS: | Onset <20 yo or >50 yo; HTN resistant to >2 meds; renal arter / epigastric bruit; atherosclerosis (aorta or peripheral arteries); abruptly worse renal fn after starting ACEI |
RAS dx studies | Renal arteriogram is definitive. If low suspicion: noninvasive angiography (MRI or CT). US |
RAS mgmt | BP meds: ACEI, ARB, diuretics. Surgery (perc transluminal angioplasty +/- stents). Nephrectomy in severe dz & risk of kidney loss 2/2 ischemia |
JNC 8 BP goals | >60 yo: <150/90. 30-59 yo: <140/90 |