Investigations
Normal result does not rule out coronary artery disease.
may show evidence of left ventricular hypertrophy or old infarction
Risk of hypertension is increased if there are features of the metabolic syndrome.
Unprovoked hypokalemia suggests hyperaldosteronism.
GFR is calculated according to the Modification of Diet in Renal Disease (MDRD) formula or the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation.[51][ Glomerular Filtration Rate Estimate by the IDMS-Traceable MDRD Study Equation ][ Glomerular Filtration Rate Estimate by CKD-EPI Equation ]
may show renal insufficiency, hyperglycemia, hypokalemia, hyperuricemia, or hypercalcemia
Risk of hypertension is increased in the setting of the metabolic syndrome.
may show high LDL, low HDL, or high triglycerides
Increased albumin excretion suggests end-organ damage.
may show proteinuria
Anemia accompanies chronic renal failure.
Polycythemia may be seen with pheochromocytoma.
anemia or polycythemia suggests secondary cause or complication
Indicated if signs/symptoms of hypo- or hyperthyroidism.
high or low if thyroid dysfunction
Indicated when unprovoked hypokalemia present.
low renin suggests hyperaldosteronism
Indicated in the following situations: BP is sustained above 150/100 mmHg on 3 measurements over different days, with hypertension resistant to 3 conventional antihypertensive drugs (including a diuretic), or controlled BP (140/90 mmHg) on 4 or more antihypertensive drugs; hypertension and spontaneous or diuretic-induced hypokalemia; hypertension and adrenal incidentaloma; hypertension and sleep apnea; hypertension and a family history of early-onset hypertension or cerebrovascular accident at a young age (40 years); hypertensive first-degree relatives of patients with primary aldosteronism.[55]
high aldosterone or failure to suppress with salt loading suggests hyperaldosteronism
Young patients (age <40 years) with severe hypertension or renal artery bruits.
Ultrasound provides hemodynamic information and magnetic resonance angiogram (MRA) provides anatomic information, in lieu of renal angiogram. CT angiography is accurate in atherosclerotic disease.
may show renal artery stenosis, renal scarring, or lesions
Indicated with symptoms/signs of catecholamine excess.
elevated catecholamines if pheochromocytoma
Indicated with signs/symptoms of catecholamine excess. This test is easier to perform than 24-hour urine screen, but has a higher rate of false positives.
elevated metanephrines if pheochromocytoma
Indicated when stigmata of Cushing disease present.
elevated in Cushing disease
Sleep study may be considered in cases of resistant hypertension and also for patients with signs or symptoms of obstructive sleep apnea.
may show results consistent with obstructive sleep apnea
Assesses left ventricular hypertrophy and left ventricular function.
Echocardiogram may have prognostic implications, but is not routinely recommended except as recommended by guidelines.[5][56]
There was increased risk of mortality and cardiovascular events in patients with increased left ventricular mass and abnormal geometric left ventricular hypertrophy on echocardiogram.[52][53]
increased left ventricular mass, decreased left ventricular systolic function, impaired left ventricular diastolic function, and increased left atrial size and decreased function
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