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

• Published in: Hypertension (Dallas, Tex. 1979) Tex. 1979), 2008-08, Vol.52 (2), p.236-240
• Main Authors: Immink, Rogier V, van den Born, Bert-Jan H, van Montfrans, Gert A, Kim, Yu-Sok, Hollmann, Markus W, van Lieshout, Johannes J
• Format: Article
• Language: English
• Subjects: Adult; Analysis of Variance; Antihypertensive Agents - administration & dosage; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood Pressure Determination; Cardiology. Vascular system; Cerebrovascular Circulation - drug effects; Cerebrovascular Circulation - physiology; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Dose-Response Relationship, Drug; Drug Administration Schedule; Electrocardiography; Female; Follow-Up Studies; Hemodynamics - drug effects; Hemodynamics - physiology; Humans; Hypertension, Malignant - diagnosis; Hypertension, Malignant - drug therapy; Hypertension, Malignant - mortality; Infusions, Intravenous; Labetalol - administration & dosage; Male; Medical sciences; Middle Aged; Nitroprusside - administration & dosage; Probability; Prospective Studies; Risk Assessment; Severity of Illness Index; Statistics, Nonparametric; Survival Rate; Treatment Outcome; Ultrasonography, Doppler, Transcranial; Vascular Resistance - drug effects
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/HYPERTENSIONAHA.108.110395

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 · %mm Hg; P