Management of hypertensive crises

A reassessment of the safety profile of monoamine oxidase inhibitors: elucidating tired old tyramine myths

This review appraises over 150 recent original papers reporting data that demonstrate the greatly reduced tyramine content of modern-day 'foods', about which the medical literature has a paucity of information. It discusses the cardiovascular pharmacology of tyramine and the characteristics, extent, risks, and treatment of the blood pressure increases that sometimes result from tyramine ingestion (the pressor response). In past decades, cheese was the only food associated with documented fatalities resulting from hypertension. Today, few foods contain problematically high tyramine levels, which is a result of changes in international food production techniques (especially the use of starter cultures), and hygiene regulations. Nowadays, even 'matured' cheeses are usually safe in healthy-sized portions. The mechanism by which tyramine may be produced in foods (by certain micro-organisms) is explained and hundreds of recent estimations of cheeses are reviewed. Numerous other previously inadequately documented foods are reviewed, including fish and soy sauces, salami-type sausages, dried meats, beers, wines, and various condiments. Evidence that the risk of harm from the pressor response has previously been overstated is reviewed, and the iatrogenic harms from hasty and aggressive treatment of hypertensive urgency are re-evaluated. Evidence now suggests that MAOIs are of comparable safety to many newer drugs and are straightforward to use. Previously held concerns about MAOIs are misplaced and some are of over-estimated consequence. The variability of pressor sensitivity to tyramine between individuals means that the knowledge and judgement of doctors, and some care, are still required.

Hypertensive retinopathy in a transgenic angiotensin-based model

Severe hypertension destroys eyesight. The RAS (renin-angiotensin system) may contribute to this. This study relied on an established angiotensin, AngII (angiotensin II)-elevated dTGR (double-transgenic rat) model and same-background SD (Sprague-Dawley) rat controls. In dTGRs, plasma levels of AngII were increased. We determined the general retinal phenotype and observed degeneration of ganglion cells that we defined as vascular degeneration. We also inspected relevant gene expression and lastly observed alterations in the outer blood-retinal barrier. We found that both scotopic a-wave and b-wave as well as oscillatory potential amplitude were significantly decreased in dTGRs, compared with SD rat controls. However, the b/a-wave ratio remained unchanged. Fluorescence angiography of the peripheral retina indicated that exudates, or fluorescein leakage, from peripheral vessels were increased in dTGRs compared with controls. Immunohistological analysis of blood vessels in retina whole-mount preparations showed structural alterations in the retina of dTGRs. We then determined the general retinal phenotype. We observed the degeneration of ganglion cells, defined vascular degenerations and finally found differential expression of RAS-related genes and angiogenic genes. We found the expression of both human angiotensinogen and human renin in the hypertensive retina. Although the renin gene expression was not altered, the AngII levels in the retina were increased 4-fold in the dTGR retina compared with that in SD rats, a finding with mechanistic implications. We suggest that alterations in the outer blood-retinal barrier could foster an area of visual-related research based on our findings. Finally, we introduce the dTGR model of retinal disease.

Emergency Room Treatment of Hypertensive Crises

AIM

The aim of the study was to evaluate efficiency of hypertensive urgency treatment using inhibitors of α1-adrenergic receptors and angiotensin converting enzyme inhibitors-ACE inhibitors in the Emergency Room of Outpatient Hospital and Polyclinic "dr Mustafa Šehovic" Tuzla in relation to age, duration and severity of hypertension.

METHODS

The study was conducted from June 2011 to May 2012 and included 120 patients of both sexes diagnosed with arterial hypertension, aged 40 to 80 with verified hypertensive urgency. The patients were divided into two groups: the control group treated with sublingual captopril and the experimental group treated intravenously with urapidil.

RESULTS

The results show that the largest number of patients belonged to age group from 60 to 69 years (34,16%), and the average age was 58 (11). The largest number of patients (38,0%) had verified hypertension for 11 to 20 years. The average systolic/diastolic artery blood pressure at reception was 213 (19) / 130 (4) mmHg. The average systolic/diastolic artery blood pressure after the first dose of 12,5 mg captopril in the control group was 177,42 (10,91) / 112,33 (3,50) mmHg, while after the first dose of 12,5 mg urapidil it was 179,25 (16,62) / 110,33 (8,78) mmHg. The average systolic/diastolic artery blood pressure after the second dose of 12,5 mg of captopril in the control group was 152,00 (6,32) / 95,50 (3,76) mmHg, while after the second dose of 12,5 mg of urapidil it was 152,55 (7,17) / 95,29 (5,04) mmHg.

CONCLUSION

Urapidil is more efficient in hypertensive urgency treatment, since the decrease of middle artery pressure (MAP) in the group treated with urapidil was statistically significant (p<0,001). No statistical significance was found between the efficiency of urapidil and the patient's age, while captopril was more efficient in older patients (p=0,02). Also, no statistically significant difference was found between the efficiency of captopril and urapidil in relation to duration of hypertension.

Clinical presentation of hypertensive crises in emergency medical services

OBJECTIVES

The objective of this study is to evaluate the incidence and clinical presentation of hypertensive crises in the Emergency medical services of the Community Health Centre "Dr. Mustafa Šehović" Tuzla in relation to age, sex, duration and severity of hypertension, as well as the prevalence of accompanying symptoms and clinical manifestations.

METHODS

The study was conducted between November 2009 and April 2010 and included 180 subjects of both sexes, aged 30-80 with a diagnosis of arterial hypertension. All subjects were divided into two groups: a control group, which consisted of subjects without hypertensive crisis (95 subjects) and an experimental group that consisted of subjects with hypertensive crisis (85 subjects).

RESULTS

The study results indicate that female subjects were significantly over- represented compared to men (60% vs. 40 %, p=0.007). The average age of the male subjects was 55.83±11.06 years, while the female subjects' average age was 59.41±11.97 years. The incidence of hypertensive crisis was 47.22%, with hypertensive urgency significantly more represented than emergency (16.47% vs. 83.53%, p<0.0001). The majority of subjects in the experimental group (28.23%) belonged to the age group of 60-69 years of age: 26.76% urgency and 35.71% emergency. The most common accompanying symptoms in hypertensive subjects were headache (75%), chest pain (48.33%), vertigo (44.44%), shortness of breath (38.88%) and nausea (33.89%). The most common symptoms in subjects with hypertensive crisis were headache (74.11%), chest pain and shortness of breath (62.35%), vertigo (49.41%), and nausea and vomiting (41.17%).

CONCLUSIONS

Chest pain, shortness of breath, nausea and vomiting were significantly over-represented in subjects with hypertensive crisis (p<0.005). Clinical manifestations of hypertensive emergencies in almost all subjects included acute coronary syndrome, and only one subject had acute pulmonary edema.

Cardiovascular issues in older adults

This article discusses selected cardiovascular conditions that nurses encounter when caring for elders hospitalized in the intensive care unit. Physiologic changes that predispose elders to these conditions, typical signs and symptoms, common diagnostic tests, and evidence-based treatment for this population are included. The implications for nursing care of critically ill elders who have these conditions are also discussed.

Intravenous nicardipine and labetalol use in hypertensive patients with signs or symptoms suggestive of end-organ damage in the emergency department: a subgroup analysis of the CLUE trial

OBJECTIVE

To compare the efficacy of Food and Drug Administration recommended dosing of nicardipine versus labetalol for the management of hypertensive patients with signs and/or symptoms (S/S) suggestive of end-organ damage (EOD).

DESIGN

Secondary analysis of the multicentre prospective, randomised CLUE trial.

SETTING

13 academic emergency departments in the USA.

PARTICIPANTS

Eligible patients had two systolic blood pressure (SBP) measures ≥180 mm Hg at least 10 min apart, no contraindications to nicardipine or labetalol and predefined S/S suggestive of EOD on arrival.

INTERVENTIONS

Medications were administered by continuous infusion (nicardipine) or repeat intravenous bolus (labetalol) for a study period of 30 min or until a specified target SBP ±20 mm Hg was achieved.

PRIMARY OUTCOME MEASURE

Percentage of participants achieving a predefined target SBP range (TR) defined as an SBP within ±20 mm Hg as established by the treating physician.

RESULTS

Of the 141 eligible patients, 49.6% received nicardipine, 51.7% were women and 81.6% were black. Mean age was 52.2±13.9 years. Median initial SBP did not differ in the nicardipine (210.5 (IQR 197-226) mm Hg) and labetalol (210 (200-226) mm Hg) groups (p=0.862). Nicardipine patients were more likely to have a history of diabetes (41.4% vs 25.7%, p=0.05) but there were no other historical, demographic or laboratory differences between groups. Within 30 min, nicardipine patients more often reached the target SBP range than those receiving labetalol (91.4% vs 76.1%, difference=15.3% (95% CI 3.5% to 27.3%); p=0.01). On multivariable modelling with adjustment for gender and clinical site, nicardipine patients were more likely to be in TR by 30 min than patients receiving labetalol (OR 3.65, 95% CI 1.31 to 10.18, C statistic=0.72).

CONCLUSIONS

In the setting of hypertension with suspected EOD, patients treated with nicardipine are more likely to reach prespecified SBP targets within 30 min than patients receiving labetalol.

CLINICAL TRIAL REGISTRATION

NCT00765648, clinicaltrials.gov.

Pharmacological management of hypertensive emergencies and urgencies: focus on newer agents

INTRODUCTION

Hypertensive crises are categorized as hypertensive emergencies and urgencies depending on the presence of acute target-organ damage; the former are potentially life-threatening medical conditions, requiring urgent treatment under close monitoring. Although several short-acting intravenous antihypertensive agents are approved for this purpose, until recently little evidence from proper trials on the relative merits of different therapies was available.

AREAS COVERED

This article discusses in brief the pathophysiology, epidemiology and diagnostic approach of hypertensive crises and provides an extensive overview of established and emerging pharmacological agents for the treatment of patients with hypertensive emergencies and urgencies.

EXPERT OPINION

Agents such as sodium nitroprusside, nitroglycerin and hydralazine have been used for many years as first-line options for patients with hypertensive emergencies, although their potential adverse effects and difficulties in use were well known. With time, equally potent and less toxic alternatives, including nicardipine, fenoldopam, labetalol and esmolol are increasingly used worldwide. Recently, clevidipine, a third-generation dihydropyridine calcium-channel blocker with unique pharmacodynamic and pharmacokinetic properties was added to our therapeutic armamentarium and was shown in clinical trials to reduce mortality when compared with nitroprusside. In view of such evidence, a change in pharmacological treatment practices for hypertensive crises toward newer and safer agents is warranted.

Pharmacokinetics, pharmacodynamics, and safety of clevidipine after prolonged continuous infusion in subjects with mild to moderate essential hypertension

Purpose

Clevidipine is a rapidly-acting intravenous dihydropyridine antihypertensive acting via calcium channel blockade. This was a randomized, single-blind, parallel-design study of a 72-h continuous clevidipine infusion.

Method

Doses of 2, 4, 8, or 16.0 mg/h or placebo were evaluated in 61 subjects with mild to moderate essential hypertension. IV clevidipine or placebo was initiated at 2.0 mg/h and force-titrated in doubling increments every 3 min to target dose, then maintained for 72 h. Blood pressure and heart rate were measured during infusion, and for 4, 6 and 8 h after termination of infusion, although oral therapy could be restarted at 4 h. Clevidipine blood levels were obtained during infusion and for 1 hour after termination.

Results

Rapid onset of drug effect occurred at all clevidipine dose levels, with consistent pharmacokinetics and rapid offset after 72-h infusion. No evidence of tolerance to the clevidipine drug effect was observed at any dose level over the 72-h infusion. No evidence of rebound hypertension was found for either 4 or 6 h after termination of the clevidipine infusion. At 8 h following cessation of clevidipine, blood pressure was not significantly higher than at baseline. Placebo-treated subjects had blood pressures lower than baseline at 8 h following infusion termination; hence, placebo-adjusted blood pressures tended to be slightly higher than baseline.

Conclusion

This study supports the use of up to 72 h of IV clevidipine therapy for the management of blood pressure, with consistent pharmacokinetic/pharmacodynamic characteristics and context insensitive half-life across the dose ranges evaluated.

Drug treatment of hypertensive crisis in children

Hypertensive crisis is a relatively rare event and is associated with significant morbidity and mortality in adults and pediatric patients alike. Rapid, safe, and effective treatment is imperative to alleviate immediate presenting clinical symptoms, prevent devastating morbidity, preserve long-term quality of life, and prevent mortality. Many medications in the hypertensive crisis arsenal have been used for nearly half a century. Nearly all treatment options have been utilized in children for decades, yet reliable data and sound clinical literature remain elusive. Every agent considered to be a first-line, second-line, or adjunctive option has yet to be evaluated in a randomized controlled trial in pediatric patients. With a paucity of clinical data to form evidence-based decisions, the clinician must rely entirely on the extrapolation from adult data and small retrospective studies, case series, and case reports of medication use in pediatric patients. Although more research in the treatment of pediatric hypertensive crisis is desperately needed, current practice demands a sharp knowledge of the pediatric clinical literature and pharmacology in this area as an essential tool to consistently improve patient outcomes with respect to morbidity and mortality.

Advances pertaining to the pharmacology and interactions of irreversible nonselective monoamine oxidase inhibitors

Recent advances clarifying the pharmacology and interactions of irreversible nonselective monoamine oxidase inhibitors that have not been considered in depth lately are discussed. These new data elucidate aspects of enzyme inhibition and pharmacokinetic interactions involving amine oxidases, cytochrome P450 enzymes, aminotransferases (transaminases), and decarboxylases (carboxy-lyases) and the effects of tyramine. Phenelzine and tranylcypromine remain widely available, and many publications have data relevant to this review. Their effect on CYP 450 enzymes is less than many newer drugs. Tranylcypromine only inhibits CYP 450 2A6 (selectively and potently). Phenelzine has no reported interactions, but, like isoniazid, weakly and irreversibly inhibits CYP 450 2C19 and 3A4 in vitro. It might possibly be implicated in interactions (as isoniazid is). Phenelzine has some clinically relevant inhibitory effects on amine oxidases, aminotransferases, and decarboxylases, and it lowers pyridoxal phosphate levels. It commonly causes pyridoxal deficiency, weight gain, sedation, and sexual dysfunction, but only rarely causes hepatic damage and failure, or neurotoxicity. The adverse effects and difficulties with monoamine oxidase inhibitors are less than previously believed or estimated, including a lower risk of hypertension, because the tyramine content in foods is now lower. Potent norepinephrine reuptake inhibitors have a strong protective effect against tyramine-induced hypertension. The newly discovered trace amine-associated receptors probably mediate the pressor response. The therapeutic potential of tranylcypromine and L-dopa in depression and Parkinson disease is worthy of reassessment. Monoamine oxidase inhibitors are not used to an extent proportionate with their benefits; medical texts and doctors' knowledge require a major update to reflect the evidence of recent advances.

The optometrist's role in the management of hypertensive crises

BACKGROUND

In hypertensive crises, ocular findings are pivotal to making correct management decisions. Joint National Committee on Prevention, Detection, and Treatment of High Blood Pressure (JNC-7) guidelines define hypertensive crises as blood pressure greater than 180/120 mmHg associated with signs or symptoms of target organ damage. Urgent cases are those without optic disc edema but that necessitate control within 24 to 72 hours. Emergent cases are those with optic disc edema, also known as malignant hypertension, demanding control within 1 to 6 hours.

CASE REPORTS

Two cases are illustrated, as might be seen in optometric offices, of severe stage II hypertension. In case 1, the acute elevation of blood pressure (220/110 mmHg), was assessed as an urgent case and was correctly managed with the primary care provider through outpatient care. The second case of acute elevation of blood pressure (250/150 mmHg) and ocular findings of severe hypertensive retinopathy was sent as an emergent case to the emergency room.

CONCLUSION

These cases exemplify optometric in-office decisions to effectively manage urgent and emergent cases of hypertensive crises. Utilizing an urgent versus emergent classification of retinopathy can lead to the appropriate management decision for these patients.

Role of clevidipine butyrate in the treatment of acute hypertension in the critical care setting: a review

Acutely elevated blood pressure in the critical care setting is associated with a higher risk of acute end-organ damage (eg, myocardial ischemia, stroke, and renal failure) and perioperative bleeding. Urgent treatment and careful blood pressure control are crucial to prevent significant morbidity. Clevidipine butyrate (Cleviprex) is an ultrashort-acting, third-generation intravenous calcium channel blocker. It is an arterial-selective vasodilator with no venodilatory or myocardial depressive effects. Clevidipine has an extremely short half-life of approximately 1 minute as it is rapidly metabolized by blood and tissue esterases. These metabolites are then primarily eliminated through urine and fecal pathways. The rapid onset and the short duration of action permit tighter and closer adjustment of the blood pressure than is possible with other intravenous agents.

Cerebral Hemodynamics During Treatment With Sodium Nitroprusside Versus Labetalol in Malignant Hypertension

In patients with malignant hypertension, immediate blood pressure reduction is indicated to prevent further organ damage. Because cerebral autoregulatory capacity is impaired in these patients, a pharmacologically induced decline of blood pressure reduces cerebral blood flow with the danger of cerebral hypoperfusion. We compared the reduction in transcranial Doppler–determined middle cerebral artery blood velocity during blood pressure lowering with sodium nitroprusside with that of labetalol. Therefore, in 15 patients, fulfilling World Health Organization criteria for malignant hypertension, beat-to-beat mean arterial pressure, systemic vascular resistance (Modelflow), mean middle cerebral artery blood velocity, and cerebrovascular resistance index (mean blood pressure:mean middle cerebral artery blood flow velocity ratio), were monitored during treatment with sodium nitroprusside (n=8) or labetalol (n=7). The reduction in mean arterial blood pressure with sodium nitroprusside (−28±3%; mean±SEM) and labetalol (−28±4%) was comparable. With labetalol, both systemic and cerebral vascular resistance decreased proportionally (−13±10% and −17±5%), whereas with sodium nitroprusside, the decline in systemic vascular resistance was larger than that in cerebral vascular resistance (−53±4% and −7±4%). The rate of reduction in middle cerebral artery blood velocity was smaller with labetalol than with sodium nitroprusside (0.45±0.05% versus 0.78±0.04% cm · s −1 · %mm Hg −1 ; P <0.05). In conclusion, sodium nitroprusside reduced systemic vascular resistance rather than cerebral vascular resistance with a larger rate of reduction in middle cerebral artery blood velocity, suggesting a preferential blood flow to the low resistance systemic vascular bed rather than the cerebral vascular bed.