Impending hypertensive emergency is frequently considered in guidelines, but neither defined nor explained

To the editor,

Impending hypertension mediated organ damage (HMOD) is included among hypertensive emergencies (HTN-Es) in numerous contemporary articles [1], books [2] and guidelines [3] but not in all [4]. Therefore, opinions vary concerning the need for this determinant (i.e. ‘impending’) in the definition of HTN-E. Discrepancies between guidelines on an important topic are not desirable.

Consequently, there is a need to decide if this part of the definition (i.e. ‘impending’) is useful or not. Common sense suggests that it is possible for an artery to rupture in a patient with blood pressure (BP) as high as 300/150 mmHg. On the other hand, experience teaches that we should treat our patient as a whole organisms and not his/her numbers, including BP numbers. We think the concept of impending HMOD can be useful in clinical practice, provided well defined by a consensus of experts. A provisional, illustrative description of the impending HMOD might be ‘the sufficiently high BP (combined with symptoms, signs, and laboratory/imaging findings) which reflects high enough probability for an acute HMOD to occur’. Indeed, this is nothing more than a starting point towards a definition of the impending HMOD. Some potential impending HMODs are included in Table 1.

Table 1. Probable examples of impending HMODs in patients with very high BP (often >200/120 mmHg) [4]. 

Number	Symptoms	Signs	Imaging	Laboratory findings	Impending HMOD
1	A sudden-onset and frequent coughing, worse in a recumbent position, without fever	Even without rales	Even before chest X-ray or lung ultrasonography	Even before (exceedingly) elevated NT pro-brain natriuretic peptide (NT pro-BNP)	Acute pulmonary oedema
2	Prolonged oliguria (with mild dyspnoea or even without it)	Particularly with worsening of leg oedema	Even before chest X-ray or lung ultrasonography	Even before exceedingly elevated NT pro-BNP	Acute pulmonary oedema (of combined cardiac and renal origin)
3	Prolonged oliguria (with mild dyspnoea or even without it)	Particularly with worsening of leg oedema	Even before chest X-ray or lung ultrasonography	Decreased creatinine clearance	Acute pulmonary oedema (of combined cardiac and renal origin)
4	Worsening angina pectoris	–	Even without ECG signs of ischaemia	Even without laboratory findings	Acute myocardial infarction (AMI)
5	Even without or with mild pain	Marfan’s syndrome	Even before CT aortography	Even before D-dimer	Acute aortic syndrome
6	Effort-induced angina pectoris (chronic coronary syndrome)	–	Diffuse ST depression with ST elevation in aVR > V1 (suggestive of left – main stenosis or its equivalent)	Before the increase in troponin and NT pro-BNP	AMI and/or acute pulmonary oedema
7	Oliguria following coronary angiography	Even prior to periorbital and arm oedema	No retention of urine on renal ultrasound	Decreased (and worsening) creatinine clearance	Acute kidney injury

Explanations for the contents No. 1–5 in Table 1 are the following:

No. 1: An interstitial pulmonary oedema precedes transudation into the alveoli and acute pulmonary oedema with rales. NT pro-BNP is not necessarily elevated in the first hour or two following this acute event [5,6].

Nos. 2 and 3: In both examples, the clinical signs of impaired renal function even without exceedingly elevated NT pro-BNP in a patient with very high BP suggest an impending acute pulmonary oedema due to both cardiac and renal failure.

No. 4: A worsening angina pectoris (‘crescendo angina’) is an impending acute myocardial infarction (AMI). If worsening angina pectoris very high BP further increases the probability of AMI – to the unacceptably high level.

No. 5: Patients with Marfan’s syndrome have pathologic changes of the aortic wall, which make them particularly prone to an acute aortic syndrome. Therefore, very high BP is a threat to an already diseased aorta and deserves prompt (but controlled) reduction of BP.

To conclude, in this article, we formulated two important problems, relevant to everyday practice: First, the discrepancy in using the term ‘impending’ in the definition of HTN-E in articles, books and guidelines. Second, the definition (or an explanation) of ‘impending HMOD’ is missing. We suggest the provisional definition of ‘the impending HMOD’ and provide several clinical examples indicate that it is possible to recognise impending acute HMOD. A clear definition of ‘impending HTN-E’ is needed before the further implementation of this concept (already used for two decades) is useful or not. A consensus on the topic would be important.

Disclosure statement

No potential conflict of interest was reported by the author(s).