Malignant hypertension and multiorgan damage: mechanisms to be elucidated and countermeasures

Trajectory of patients consulting the emergency department for high blood pressure values

OBJECTIVES

Emergency department (ED) visits for high blood pressure are increasing in frequency. We aimed to map those patients' trajectory, from referral sources to the type of care received at the ED to anticipated actions for future high blood pressure concerns, and to better understand their reasons for consulting the ED for high blood pressure values.

METHODS

Between 2018 and 2020, patients who presented to the Montreal Heart Institute's ED for elevated blood pressure were recruited in a prospective observational study including a post hoc structured telephone interview and medical chart review. Five possible referral sources were predetermined. We provided proportions and 95% confidence intervals.

RESULTS

A total of 100 patients were recruited (female: 59%, mean age: 69 ± 12). A majority (93%, 95% CI 88-98%) possessed a home blood pressure device, among which 46% (95% CI 36-56%) remembered receiving advice for its use. The main referral sources for high blood pressure to the ED were self-reference (53%, 95% CI 43-63%), advice of a lay person (19%, 95% CI 11-27%) or a nurse (13%, 95% CI 6-20%). Mainly, patients reported being concerned by concomitant symptoms or experiencing acute medical consequences (44%, 95% CI 34-54%), having followed the recommendation of a third party (33%, 95% CI 24-42%), or having concerns about their medication (6%, 95% CI 1-11%). Two weeks following their ED visits, consulting ED remained the main choice for future concerns about high blood pressure for 27% of participants. When specifically asked if they would return to the ED for elevated blood pressure, 73% (95% CI 64-83%) said yes.

CONCLUSIONS

Most patients who consulted the ED for elevated blood pressure values were self-referred. More can be done to promote blood pressure education, effective use of personal blood pressure devices, and recommendations for patients and health professionals when confronted with high blood pressure results.

Circulating microRNAs May Serve as Biomarkers for Hypertensive Emergency End-Organ Injuries and Address Underlying Pathways in an Animal Model

There is an incomplete understanding of the underlying pathophysiology in hypertensive emergencies, where severely elevated blood pressure causes acute end-organ injuries, as opposed to the long-term manifestations of chronic hypertension. Furthermore, current biomarkers are unable to detect early end-organ injuries like hypertensive encephalopathy and renal thrombotic microangiopathy. We hypothesized that circulating microRNAs (c-miRs) could identify acute and chronic complications of severe hypertension, and that combinations of c-miRs could elucidate important pathways involved. We studied the diagnostic accuracy of 145 c-miRs in Dahl salt-sensitive rats fed either a low-salt (N = 20: 0.3% NaCl) or a high-salt (N = 60: 8% NaCl) diet. Subclinical hypertensive encephalopathy and thrombotic microangiopathy were diagnosed by histopathology. In addition, heart failure with preserved ejection fraction was evaluated with echocardiography and N-terminal pro-brain natriuretic peptide; and endothelial dysfunction was studied using acetylcholine-induced aorta ring relaxation. Systolic blood pressure increased severely in animals on a high-salt diet (high-salt 205 ± 20 mm Hg vs. low-salt 152 ± 18 mm Hg, p < 0.001). Partial least squares discriminant analysis revealed 68 c-miRs discriminating between animals with and without hypertensive emergency complications. Twenty-nine c-miRs were strongly associated with hypertensive encephalopathy, 24 c-miRs with thrombotic microangiopathy, 30 c-miRs with heart failure with preserved ejection fraction, and 28 c-miRs with endothelial dysfunction. Hypertensive encephalopathy, thrombotic microangiopathy and heart failure with preserved ejection fraction were associated with deviations in many of the same c-miRs, whereas endothelial dysfunction was associated with a different set of c-miRs. Several of these c-miRs demonstrated fair to good diagnostic accuracy for a composite outcome of hypertensive encephalopathy, thrombotic microangiopathy and heart failure with preserved ejection fraction in receiver-operating-curve analyses (area-under-curve 0.75–0.88). Target prediction revealed an enrichment of genes related to several pathways relevant for cardiovascular disease (e.g., mucin type O-glycan biosynthesis, MAPK, Wnt, Hippo, and TGF-beta signaling). C-miRs could potentially serve as biomarkers of severe hypertensive end-organ injuries and elucidate important pathways involved.