Classification of hypertensive crises, including malignant hypertension, has evolved over time. As first described by Volhard and Fahr , malignant hypertension was characterized by severe hypertension, renal insufficiency, fibrinoid necrosis of renal arterioles, retinopathy with papilledema, and a rapidly progressive and fatal clinical course. Subsequently, the definition was expanded to include severe hypertension accompanied by papilledema (grade IV Keith-Wagener retinopathy). In contrast, accelerated hypertension was considered to be severe elevation of blood pressure (BP) in the presence of retinal hemorrhages and exudates, but without papilledema (grade III Keith-Wagener retinopathy) . Subsequent studies demonstrated that severe hypertension complicated by retinal hemorrhages and exudates with or without papilledema had similar clinical features and prognosis, so that the terms malignant and accelerated hypertension came to be used interchangeably . Presently, the terms hypertensive emergency, which includes malignant hypertension, and urgency are preferred . Hypertensive urgency is arbitrarily defined by the absolute level of BP (SBP >180 or DBP >120 mmHg) and hypertensive emergency is defined by the presence of acute end-organ damage and typically in the setting of severely elevated BP .
In spite of the definition used, clinicians frequently face the challenge of diagnosing and treating hypertensive crisis in their offices or in the emergency department. Although the cause of hypertensive crisis is often unknown, the identification of prognostic predictors that correctly identify higher risk patients might allow for application of more effective treatment strategies. In this issue of the Journal of Hypertension, Shantsila et al.  analyzed the impact of pulse pressure (PP) on outcomes in a cohort of 365 patients with malignant hypertension identified from The West Birmingham Malignant Phase Hypertension Study. The definition of malignant hypertension was DBP more than 130 mmHg in association with bilateral retinopathy including hemorrhages and/or cotton wool spots or exudates, with or without papilloedema. After a median follow-up of 7 years, 203 (55%) and 39 (11%) patients were dead or had started dialysis, respectively, confirming the devastating effects of malignant hypertension. Age, smoking status, severity of renal failure (assessed by proteinuria and creatinine levels) at presentation were identified as independent predictors of the risk of death or dialysis. DBP and SBP, mean arterial pressure and PP at baseline did not predict these same outcomes.
The degree of BP elevation does not correlate closely with the severity of end-organ deterioration [6,7]. Lack of predictive value of PP in the present study may be explained by various reasons as discussed by authors. Furthermore, the underlying pathophysiologic mechanisms related to BP elevation and PP in patients with malignant hypertension differ from those in patients with chronic hypertension. In the present study, the increases in PP were mostly determined by elevations in SBP rather than reductions in DBP, which likely does not represent changes in age-related arterial stiffness. Among older individuals, in whom vascular stiffness is common, both reductions in DBP and increases in SBP determine PP elevation . The acute organ deterioration encountered in patients with hypertensive emergencies is more likely attributable to impairment of autoregulatory function secondary to maladaptive changes in a number of neurohumoral and inflammatory factors .
It is of importance, as demonstrated by Shantsila et al., that an absence of symptoms (shortness of breath, chest pain, and focal neurologic deficits) does not rule out malignant hypertension. In the current analysis, presence of proteinuria and elevated creatinine levels were independent predictors for both death and dialysis, whereas the presence of hematuria predicted future dialysis . These findings highlight that currently there is a lack of evidence-based recommendations to guide physicians on how to best exclude acute end-organ damage, and that over reliance on the absence of symptoms may delay or prevent critically needed treatment . The current findings support further investigation to identify the clinical utility of potentially predictive markers of acute organ deterioration in asymptomatic patients with severely elevated BP, including electrocardiograms, cardiac enzymes, brain-natriuretic peptide, urinalysis, creatinine, full blood count, chest radiography and computed tomography of the brain .
Due to a lack of evidence, clinical management of patients with malignant hypertension remains controversial. If diagnostic assessments indicate acute organ deterioration, patients should be considered to be having an hypertensive emergency, warranting admission into an ICU, with prompt BP reduction and, if appropriate, treatment of specific end-organ complications. However, in the absence of acute end-organ deterioration, the benefit of prompt BP reduction is unclear, with some advocating outpatient referral for reassessment and management prior to beginning of antihypertensive treatment in the emergency department , and others suggesting immediate initiation of pharmacologic treatment in select patients [10,11]. If immediate treatment is not initiated, patients should, at a minimum, be referred to a primary care physician for prompt follow-up, or, alternatively, admitted to hospital for BP control.
In conclusion, this article demonstrates that in a patient presenting with a severely elevated BP, accurate and prompt identification of acute end-organ damage, and appropriate clinical management are more important than absolute BP levels. Clinicians should remember that when managing hypertensive crises, a comprehensive evaluation, including a proper patient interview and physical examination and appropriate laboratory testing are more important than the BP level alone.
Conflicts of interest
There are no conflicts of interest.
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