Hypertensive urgencies: Treating the mercury?

Abstract

[Ann Emerg Med. 2003;41:530-531.]

Introduction

In their excellent review of severely increased blood pressure in the emergency department, Shayne and Pitts¹ make several noteworthy points, none more important than their caution against treating the numbers, that is, attempting to lower a very high blood pressure in the absence of evidence of acute damage to the main target end organs of brain, retina, heart, aorta, or kidneys.² Consistent with the approach traditionally taken in standard emergency medicine texts, these authors have stratified hypertension into 3 main categories: Emergent, urgent, and uncontrolled (ie, elevated blood pressure that is neither emergent nor urgent).3, 4

There is general agreement, supported by reasonable evidence,5, 6 that hypertensive emergencies, although now uncommon in developed countries, require parenteral medication to regain the endothelial tone and end organ autoregulation that appear to be lost in this mysterious disorder.⁷ At the other end of the hypertensive spectrum, there is also general agreement, supported by strong evidence,⁸ that patients with elevated blood pressure should be referred to a primary care provider for diagnostic confirmation and gradual lowering of blood pressure over a period of weeks to months.

Difficulties begin to surface when one tries to make sense of the ambiguous category of hypertensive urgencies. Shayne and Pitts¹ struggle with this elusive concept, acknowledging that there is little consensus on what constitutes a hypertensive urgency, or even whether such a condition exists. Ultimately, they settle on a definition that requires end organ compromise, but without evidence of the active vasculopathy thought to characterize true hypertensive emergencies.⁷ Wisely, they go on to stress the complete lack of evidence demonstrating any benefit associated with acute blood pressure reduction in such patients,⁹ while citing the sometimes disastrous consequences of successfully lowering the blood pressure in presumed hypertensive urgencies.10, 11 Thus, the only feature of a putative hypertensive urgency that might conceivably be urgent is not the need for prompt (or even gradual) blood pressure reduction during the ED visit, but rather for expeditious outpatient follow-up. Indeed, even the necessity of arranging immediate follow-up can be questioned on the basis of evidence drawn from the Veterans' Administration Cooperative Trial, which found that the 70 patients with diastolic blood pressures between 115 and 129 mm Hg randomized to placebo had zero (95% confidence interval 0% to 5%) adverse events over the next 2 months.⁸

Thus, the best available evidence, taken from a randomized clinical trial that, for sound ethical reasons, cannot be repeated,⁸ suggests that the most sensible approach to a patient in the ED found to have very high blood pressure, without evidence of acute end organ damage, is referral for outpatient management of a serious disease that needs to be treated—not urgently, but for life. Focusing on the height of the column of mercury in the sphygmomanometer, particularly if one is unfortunate enough to succeed in reducing these numbers, confers no demonstrable benefit on the patient and risks doing harm.