Clinical Pearls & Morning Reports
Blood-pressure elevations above 180/110 to 120 mm Hg can result in acute injury to the heart, brain, and the microvasculature. If acute hypertension-mediated target-organ damage is present, the condition is labeled “hypertensive emergency” and demands immediate and aggressive treatment to limit progressive injury. Read the Clinical Practice Article here.
Q: What is the most common precipitating factor for acute severe hypertension?
A: Most patients presenting with acute severe hypertension are already known to be hypertensive and have received treatment. Nonadherence to prescribed antihypertensive medications is the most common precipitating factor. Other common precipitating factors for acute severe hypertension include dietary sodium indiscretion; use of prescribed, over-the-counter, or illicit drugs (e.g., cocaine, amphetamines, sympathomimetic agents, nonsteroidal antiinflammatory drugs, and high-dose glucocorticoids); anxiety or panic; and acute stroke or heart failure, which can be both cause and consequence of severe hypertension.
Q: Are there risks associated with episodes of severe hypertension that are not associated with acute target-organ damage (hypertensive urgency)?
A: Even in the absence of acute target-organ damage, episodes of severe hypertension have long-term implications. In a study involving 2435 patients with a previous transient ischemic attack, an isolated systolic blood pressure above 180 mm Hg (without symptoms) was associated with an increase in stroke risk during 3 years of follow-up by a factor of 5, as compared with no episodes of systolic blood pressure above 140 mm Hg, regardless of usual blood pressures. Similarly, a prospective cohort study showed that patients who had an admission with hypertensive urgency had a 50% higher risk of fatal or nonfatal cardiovascular events than controls, despite similar blood-pressure levels during follow-up.
A: There are relatively few trials comparing different agents for hypertensive emergency and hypertensive urgency. Treatment is largely determined by an understanding of the pathophysiological features, the presence and type of target-organ injury, the availability and costs of medications, and physician experience with given agents. There is considerable variability in practice regarding the choice of medications. All patients should be admitted to an intensive care unit and treated with intravenous antihypertensive drugs on the basis of the clinical scenario. In the United States, labetalol, nitroglycerin, nicardipine, hydralazine, and nitroprusside are the most commonly used agents. Of these medications, hydralazine has unpredictable effects, often leads to excessive blood-pressure lowering, and should generally be avoided as a first option. The appropriate timing for starting or restarting oral drugs is uncertain. The recommended pace and intensity of blood-pressure reduction vary depending on the presence of certain conditions. Consensus recommendations are based on very limited data and in some cases are not uniform across guidelines.
A: Most patients without acute target-organ damage can be cared for as outpatients. Treatment with guideline-concordant long-acting medications should be started, reinstated, or adjusted, and follow-up should be scheduled within 1 to 7 days. In a study involving more than 500 patients presenting to an emergency department with severe hypertension, blood pressure fell to less than 180/110 mm Hg after 30 minutes of quiet rest (before medication administration) in approximately one third of the patients. If quiet rest or control of anxiety or other precipitating factors is insufficient, an oral antihypertensive agent may be given. Intravenous medications are discouraged in this context.