Article

Intravenous labetalol for the treatment of hypertension after carotid endarterectomy

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Abstract

Hypertension after carotid endarterectomy has a variable incidence ranging up to 56%. Blood pressure (BP) control is essential due to possible increased risk of morbidity from neurologic deficits or cardiovascular complications. This study evaluated intravenous labetalol for control of hypertension after carotid endarterectomy. Sixty ASA II-IV patients were studied; 20 developed BP high enough for treatment with labetalol. The anesthetic technique was standardized. Labetalol was administered at the conclusion of surgery as a 20-mg bolus over two minutes followed by 40 mg every 10 minutes until the desired BP was achieved (BP less than or equal to 10% above average preoperative BP or less than 150 mmHg, systolic) or 300 mg had been given. The mean total dose of labetalol was 42.0 +/- 33.0 mg (mean +/- SD) and mean time to reach the desired BP was 16.2 +/- 21.4 minutes. Systolic, diastolic, mean arterial pressure and heart rate significantly decreased after labetalol treatment and remained so for the remainder of the 180-minute study period. There was no hypotension, bradycardia, evidence of myocardial ischemia or central nervous system dysfunction present with labetalol treatment. Blood samples were obtained for determination of plasma renin activity, epinephrine, and norepinephrine in 10 patients who developed hypertension and received labetalol, and 10 patients who did not develop hypertension. In the patients developing hypertension, there was a significant elevation in epinephrine just before treatment, that decreased by 30 minutes after treatment. Norepinephrine levels became significantly elevated five minutes after labetalol treatment in the group with hypertension and remained elevated for 120 minutes. Concomitantly, there was a significantly lower plasma renin activity seen in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

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... Between 1989 and 2000, 173 patients had undergone unilateral CE at the Department of Vascular Surgery of the University Medical Center Nijmegen, the Netherlands. Indications for CE included (recurrent) transient ischemic attack (TIA) or stroke in the past 6 months in addition to a carotid stenosis of at least 70 % [1]. Surgery had been carried out in the same institution in a standardized fashion and by experienced surgeons. ...
... We included two control groups in this study. The first control group consisted of 9 patients (7 males, 2 females) with a uni-or bilateral carotid stenosis (CS) in whom CE was not indicated due to either (Table 1) [1]. The second group consisted of 12 healthy controls (HC, 11 males, 1 female), who were recruited through advertisement in a local newspaper. ...
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Carotid endarterectomy (CE) may be complicated by the clinical syndrome of baroreflex failure. Alterations of baroreflex function may also account for the frequently observed blood pressure lability in the first hours following surgery. We investigated the long-term effects of unilateral CE on baroreflex control of function and blood pressure. We investigated 14 patients after unilateral CE (13 m:1 f, 64.8 +/- 6.5 years), 9 patients with a surgically untreated uni-/bilateral carotid stenosis (CS, 7 m:2 f, 57.6 +/- 10.7 years) and 12 healthy controls (HC, 11 m:1 f, 60.9 +/- 7.9 years) by means of Valsalva maneuver, active standing, forced breathing, cold face test, cold pressor test and mental arithmetic. Ambulatory blood pressure level and variability were determined from 24-hour Spacelabs and 5-hour beat-to-beat Portapres recordings. Baroreflex sensitivity (derived from phase IV Valsalva maneuver) was significantly lower in CE (1.53 +/- 0.83 ms/mmHg) than in CS (4.39 +/- 2.27, p = 0.002) and HC (5.34 +/- 3.78, p = 0.003). CE patients exhibited a decreased reflex control of heart rate in response to Valsalva's maneuver and active standing without orthostatic hypotension. Office blood pressure levels before and after endarterectomy were similar, as were ambulatory blood pressure levels in the three groups. Ambulatory blood pressure variability was higher in CE and CS than in HC, but not different between CE and CS. Unilateral CE causes a long-term impairment of baroreflex function, resulting in an attenuated reflex control of heart rate, but no hypertension or blood pressure lability.
... In a study of healthy adults receiving IV dextroamphetamine, Nurnberger et al. (1984) demonstrated propranolol, a non-selective ␤-blocker, attenuated increases in HR and SBP. In another study of anesthesia patients receiving ephedrine for hypotension who then became hypertensive as a result, the authors reported resolution of hypertension with the non-selective ␤and ␣1-blocker labetalol (Goldberg et al., 1989). The interaction of the methamphetamine precursor pseudoephedrine (a common decongestant), and ␤-blockers was evaluated in a prospective study in which propranolol and atenolol decreased SBP and HR, but not DBP (Mores et al., 1999). ...
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Overdose of amphetamine, related derivatives, and analogues (ARDA) continues to be a serious worldwide health problem. Patients frequently present to the hospital and require treatment for agitation, psychosis, and hyperadrenegic symptoms leading to pathologic sequelae and mortality. To review the pharmacologic treatment of agitation, psychosis, and the hyperadrenergic state resulting from ARDA toxicity. MEDLINE, PsycINFO, and the Cochrane Library were searched from inception to September 2014. Articles on pharmacologic treatment of ARDA-induced agitation, psychosis, and hyperadrenergic symptoms were selected. Evidence was graded using Oxford CEBM. Treatment recommendations were compared to current ACCF/AHA guidelines. The search resulted in 6082 articles with 81 eligible treatment involving 835 human subjects. There were 6 high-quality studies supporting the use of antipsychotics and benzodiazepines for control of agitation and psychosis. There were several case reports detailing the successful use of dexmedetomidine for this indication. There were 9 high-quality studies reporting the overall safety and efficacy of β-blockers for control of hypertension and tachycardia associated with ARDA. There were 3 high-quality studies of calcium channel blockers. There were 2 level I studies of α-blockers and a small number of case reports for nitric oxide-mediated vasodilators. High-quality evidence for pharmacologic treatment of overdose from ARDA is limited but can help guide management of acute agitation, psychosis, tachycardia, and hypertension. The use of butyrophenone and later-generation antipsychotics, benzodiazepines, and β-blockers is recommended based on existing evidence. Future randomized prospective trials are needed to evaluate new agents and further define treatment of these patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
... preparations include labetalol, Arterial pressure management and CEA esmolol, metoprolol, atenolol or clonidine. Labetalol and esmolol have been found effective in neurosurgical patients and both can be titrated to effect, 35 but other drugs may be used. 43 Beta adrenoceptor antagonists are useful to counteract the reflex tachycardia seen with other agents. ...
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Acute perioperative changes in arterial pressure occur frequently, particularly in patients with cardiovascular disease or those receiving vasoactive medications, or in relation to certain cardiovascular surgical procedures. Both hypo- and hypertension are common in patients undergoing carotid surgery because of unique patho-physiological and surgical factors. Poor arterial pressure control is associated with increased morbidity and mortality after carotid endarterectomy, but good control of arterial pressure is often difficult to achieve in practice. New guidelines have emphasized the benefits of performing carotid surgery urgently in patients with acute neurological symptoms. This strategy may make perioperative arterial pressure control more challenging. However, few specific data are available to guide individual drug therapy. The incidence, implications, and aetiology of haemodynamic instability associated with carotid surgery are reviewed, and some recommendations made for its management. Close monitoring and titration of therapy are probably the most important considerations rather than specific choice of agents.
... 7 Some degree of hemodynamic instability (hypertension, hypotension, and bradycardia) commonly develops after CEA. [8][9][10][11][12] Although these postoperative cardiovascular fluctuations are usually transient, hemodynamic instability after CEA has been linked to surgical mortality and morbidity, especially the occurrence of stroke and cardiac complications. 13 The mechanism of post CEA hemodynamic instability remains unclear. ...
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Purpose To investigate the pattern of catecholamine response in patients undergoing carotid endarterectomy (CEA) or carotid artery stenting (CAS). Methods Adrenaline, noradrenaline, and renin levels were measured at 5 time points in 12 patients undergoing 13 CEAs (1 bilateral) and 13 patients undergoing unilateral CAS. Arterial blood samples were taken at the following time points: (1) after induction in CEA patients or 5 minutes following first contrast injection in CAS patients, (2) 5 minutes following ICA clamp release in surgical patients or deflation of the balloon in the CAS cohort, (3) 60 minutes following ICA clamp release in surgical patients or deflation of the balloon in the CAS cohort, and (4) 24 hours following the procedure. Intraoperative blood pressure and heart rate were recorded using radial arterial monitoring. Changes in adrenaline, noradrenaline, and renin levels are expressed as ratios versus baseline. Results Patterns of adrenaline and noradrenaline release were significantly different in patients undergoing CAS and CEA, with much higher and more variable surges of adrenaline and noradrenaline occurring in CEA patients. Adrenaline and noradrenaline levels increased significantly over baseline following carotid artery clamping in patients undergoing CEA (noradrenaline ratio before clamping: 1.54±1.25, 24 hours after unclamping: 8.38±16.35 [p<0.001]; adrenaline ratio before clamping: 1.12±0.49, 60 minutes after unclamping: 17.59± 19.14 [p<0.001]). Conversely, in patients undergoing CAS, catecholamine levels remained unchanged (noradrenaline ratio before dilation: 0.96±0.23, 24 hours after the procedure: 0.92±0.32 [p = NS]; adrenaline ratio before dilation: 0.83±0.33, 60 minutes after balloon deflation: 0.56±0.32 [p = NS]). Conclusions CAS is associated with a significantly less marked catecholamine response than CEA, which may reflect down-regulation of the sympathetic nervous system in response to carotid sinus stimulation during carotid angioplasty.
... Drugs that have been used in this setting include nitroprusside, phentolamine and labetalol. 37,38 Apart from antihypertensive treatment, adequate analgesic and sedative therapy for relief of postsurgical discomfort and baroreflex failure related symptoms such as headache and palpitations are indicated. ...
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The arterial baroreflex buffers abrupt transients of blood pressure and prevents pressure from rising or falling excessively. In experimental animals, baroreceptor denervation results in temporary or permanent increases in blood pressure level and variability, depending on the extent of denervation. In humans, the clinical syndrome of baroreflex failure may arise from denervation of carotid baroreceptors following carotid body tumour resection, carotid artery surgery, neck irradiation and neck trauma. The syndrome is characterised by acute malignant hypertension and tachycardia followed by labile hypertension and hypotension. Baroreflex failure can be a cause of hypertension and should also be considered in the differential diagnosis of pheochromocytoma. Patients with suspected baroreflex failure should be referred to specialised centres for diagnostic testing and treatment.
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Acute perioperative changes in arterial pressure occur frequently, particularly in patients with cardiovascular disease or those receiving vasoactive medications, or in relation to certain cardiovascular surgical procedures. Hemodynamic Instability (HI) are common in patients undergoing carotid revascularization because of unique patho-physiological and surgical factors. The operation, by necessity, disrupts the afferent pathway of the baroreflex, which can lead to postendarterectomy HI. Poor arterial pressure control is associated with increased morbidity and mortality after carotid revascularization, but good control of arterial pressure is often difficult to achieve in practice. The incidence, implications, and etiology of HI associated with carotid surgery are reviewed, and some recommendations made for its management. Close monitoring and titration of therapy are probably the most important considerations rather than specific choice of agents.
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Despite its high prevalence, hypertension remains undiagnosed, untreated, or uncontrolled in many patients.
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Blood pressure changes following carotid endarterectomy were studied in 39 patients undergoing 42 carotid endarterectomies, in order to establish the incidence of hypertension and to study the use of hydrallazine for its treatment. Hypertension occurred in 28 cases (66%) and was treated with intravenous hydrallazine in a dose of 20 ±8 mg; this resulted in a systolic blood pressure fall of 46 ±22 mmHg, diastolic blood pressure fall of 24 ± 12 mmHg, mean blood pressure fall of 31 ± 15 mmHg, and a pulse rate increase of 7 ±9 beats per minute. Hydrallazine is a safe, effective drug for the treatment of intraoperative hypertension.
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We studied the effects of labetalol, an alpha- and beta-adrenoceptor antagonist, on maximum exercise heart rate and on plasma renin, aldosterone, noradrenaline, and adrenaline levels at rest and during exercise in hypertensive patients. The dose of labetalol was doubled weekly from 0.3 to 2.4 g per day. The maximum exercise heart rate fell significantly during labetalol treatment, and there was a significant correlation between exercise tachycardia and the dosage of labetalol. Plasma renin activity and aldosterone concentration at rest decreased during treatment with labetalol. The exercise-induced increase in plasma renin activity was reduced by labetalol. Labetalol did not cause any significant changes in plasma noradrenaline and adrenaline at rest or during exercise.
Article
SUMMARY Sixty patients out of 1,844 recovery room admissions had significant postoperative arterial hypertension. Nearly 60% of them had a history of hypertension. The post-operative hypertension usually began within 30 min from the end of operation and lasted about 2 hours. In 20% of the patients it lasted 3 hours or longer. Complications attributable to hypertension were confined to this latter group. The principal factors possibly contributing to the pressure elevations were pain (35%), hypercarbia (15%) and emergence excitement (16%). Ten of the patients (17%) had no demonstrable cause for hypertension. The hypertension in this group appeared to have a shorter and more benign course.
Article
In a series of 683 consecutive carotid endarterectomies, there were 16 postoperative myocardial infarctions which resulted in five deaths. Of 399 operations on patients with no previous history of heart disease, there were only two myocardial infarctions (0.5%). Two hundred and eighty-four operations were performed on patients with heart disease, and vasopressors were administered in 135 of these procedures. For these patients the risk of myocardial infarction increased from 2.0% to 8.1% with the use of vasopressors (P less than 0.001). The management of the patient with stable heart disease undergoing carotid endarterectomy is discussed.
Article
Seventy-nine patients undergoing staged bilateral carotid endarterectomy were studied to determine the relationship of perioperative hypertension to postoperative neurologic deficits. Six of the eight neurologic deficits following 158 endarterectomies (5%) occurred after the first operation, all being temporary. Comparison of the mean blood pressures in patients with and without postoperative strokes revealed no statistically significant differences. Patients on antihypertensive medications were at a significantly higher risk of developing postoperative strokes. A trend towards higher blood pressure was noted following the second endarterectomy, particularly when they were staged more than 60 days apart. Based on our findings, a cautious approach is warranted in the treatment of postendarterectomy hypertension.
Article
Arterial pressure regulation is often labile following carotid endarterectomy. Hemodynamic data from 100 consecutive endarterectomies allowed definition of three distinct postoperative blood pressure responses. A hypotensive response (group I) affected 28 patients in whom mean arterial pressure decreased from 168 +/- 29/90 +/- 15 mm Hg before operation to 110 +/- 21/68 +/- 16 mm Hg after operation (P less than 0.001). Maximum hypotension occurred 5.3 hours after endarterectomy. The preoperative pulse, 80 +/- 9 beats/min, fell to a low of 64 +/- 12 beats/min after operation (P less than 0.001). A significant hypertensive response (group II) affected 19 patients in whom mean blood pressure rose from 160 +/- 29/87 +/- 15 to 223 +/- 32/110 +/- 22 mm Hg (P less than 0.001). Maximum hypertension was noted 2.3 hours after endarterectomy. This was unaccompanied by significant pulse changes. Fifty-three patients remained normotensive (group III). Their preoperative blood pressure (150 +/- 14 mmHg). Fluctuations in pressure did not correlate with age, indication for operation, or degree of ipsilateral and contralateral carotid arterial stenosis. Postendarterectomy hypotension and hypertension appear to represent transient baroreceptor dysfunctions.
Article
Two patients with transient ischemic attacks and subsequent minor cerebral infarction had repair of very tight carotid stenosis, 4 and 5 weeks respectively after their stroke. Each developed intracerebral hemorrhage when hypertension was uncontrolled during the post-operative period. Hypertension is a significant complication of carotid endarterectomy, and may be a prominent factor in the development of intracerebral hemorrhage post-carotid endarterectomy.
Article
The effects of an intravenous infusion of nitroglycerin were studied in 20 acutely hypertensive patients during coronary-artery surgery. Eight patients had histories of essential hypertension and six had been treated for it. They were anesthetized with morphine, diazepam, N2O, O2, pancuronium, and enflurane. Control measurements were obtained after sternotomy. Nitroglycerin was then administered until the blood pressure returned to normal, and the measurements then repeated. The mean dose of nitroglycerin was 80.0 +/- 4.7 mug/min, or 0.96 mug/kg/min. This produced significant decreases (P less than .05) in systolic, diastolic, and mean arterial blood pressures, central venous pressure, pulmonary capillary wedge pressure, systemic vascular resistance, and left ventricular stroke work index. Cardiac index, stroke index, and heart rate were unchanged. Two indices of myocardial oxygen demand (rate-pressure product and tension-time index) were significantly decreased by nitroglycerin (P less than .005). Fifty per cent of the patients had improvement in ST-segment depression on the electrocardiogram. These findings demonstrate that nitroglycerin can be safely administered intravenously during operation, and suggest that nitroglycerin decreases myocardial oxygen demand and relieves myocardial ischemia.
Article
The antihypertensive efficacy and safety of IV labetalol were evaluated and compared with the efficacy and safety of IV hydralazine in the treatment of postoperative hypertension. Twenty patients undergoing major noncardiac surgery were entered into the study. Patients were randomized and treated for postoperative hypertension with either labetalol (n = 10) or hydralazine (n = 10). Labetalol and hydralazine both produced significant reductions in arterial blood pressure (p less than 0.001) within 10 minutes, which lasted at least 2 hours. In addition, labetalol produced a significant reduction in the heart rate and rate-pressure product without creating any adverse effects. In contrast, hydralazine produced significant sinus tachycardia requiring IV propranolol in three patients, two of whom developed transient ST segment depression. These results indicate that labetalol is safe and effective for the control of postoperative hypertension, especially in those patients who are least able to tolerate tachycardia.
Article
• Hypertension following carotid endarterectomy occurs frequently but is poorly understood. Its occurrence has been correlated with an increased incidence of neurologic complication. We identified those factors that correlate with an increased incidence of post—carotid endarterectomy hypertension. The records of 100 patients who underwent carotid endarterectomy at UCLA Medical Center from November 1981 to September 1983 were examined. One hundred fifty variables were surveyed to determine those factors associated with this problem. Fifty-eight percent of the study patients developed post—carotid endarterectomy hypertension (an increase in systolic blood pressure greater than 35 mm Hg over baseline, and/or blood pressure requiring treatment with sodium nitroprusside). Of patients who developed this problem, 93% had diabetes mellitus, 75% received isoflurane anesthesia, 71% had peripheral vascular occlusive disease, 71% underwent ipsilateral transient ischemic attacks, and 65% had high-grade ipsilateral carotid stenosis. These variables have in common the loss of or interference with cerebral autoregulation. Central dysautoregulation may set the stage for a positive feedback mechanism that results in increased blood pressure. Anesthetic agents that do not interfere with cerebral auto-regulation may reduce the incidence of this complication, and an aggressive treatment program may prevent neurologic complications. (Arch Surg 1987;122:1153-1155)
Article
Labetalol is a combined α-and β-adrenoreceptor blocking agent. A loading dose may be used to antagonize sympathetic overactivity rapidly after surgery and be followed by a continuous infusion to achieve a stable effect. The haemodynamic effects and pharmacokinetics of this method of labetalol administration were studied in six rewarmed, extubated and sedated patients 15±2 h after aortobifemoral bypass surgery. Patients were monitored with radial and thermistor-tipped pulmonary artery catheters. Labetalol 1.5 mg kg−1 was injected i.v. over 5 min and a maintenance infusion of 0.2 mg kg −1 h−1 was started 30 min later and continued for 5.5 h. Within 5 min of the loading dose, i.v. labetalol induced significant (P < 0.05) decreases in mean arterial pressure (−32 ±11%), in heart rate (−20±11%) and in cardiac index (−26 ± 15%) that lasted throughout the infusion. Changes in systemic vascular resistance were not uniform, but an increase was not observed in any patient. Mean stroke volume index and ventricular filling pressures were not significantly affected by labetalol administration. The mean measured steady state plasma concentration (Css) (264 ±46 ng ml−1) was higher than predicted (170 ng ml−1) because the clearance (13.1 ±2.4 ml kg−1 min−1) was lower than that used to calculate the infusion rate. We conclude that labetalol is an effective antihypertensive agent in the postoperative period. A Css can be achieved rapidly by such i.v. administration and this offers the advantage of inducing rapid and stable haemodynamic effects. However, calculation of the infusion rate must be based on a clearance of 13 ml kg−1 min−1.
Article
Two alternative anesthetic techniques for use during carotid endarterectomy were studied in a series of 424 procedures. A total of 248 were performed in patients under general anesthesia and 176 patients received regional block anesthesia. Perioperative instability of blood pressure was noted in 108 patients. Hypertension was noted in 17.7% of those under general anesthesia vs 20.5% of those under regional block anesthesia. Intravenous vasodilator agents were used for 19.62 hr (+/- 4.33) in the general anesthesia group vs 1.4 hr (+/- 0.44) in the regional block anesthesia group (p less than .02). Perioperative hypertension correlated best with uncontrolled preoperative hypertension. Under regional block anesthesia the incidence of shunting was 4.5%. The 1 month operative mortality for the entire carotid series was 1.2% (5/424). There were three stroke-related deaths. In addition, two nonfatal major strokes and two minor strokes occurred in patients who received general anesthesia vs one nonfatal major stroke in a patient who received regional block anesthesia.
Article
Regional myocardial blood flow before and after sublingual nitroglycerin was measured in 10 patients with coronary artery disease. During thoracotomy, (133)Xe was injected directly into the subepicardium in diseased regions of the anterior left ventricular wall, and washout rates were recorded with a scintillation counter. All disappearance curves were closely approximated by two exponential decays analyzed as two parallel flow systems by the compartmental method. The appearance of a double exponential decay pattern in diseased regions suggests that the slow phase was associated with collateral blood flow, although nonhomogeneous myocardium-to-blood partition coefficients for xenon cannot be excluded. Nitroglycerin increased the rapid phase flow in 9 of 10 patients and the slow flow in 7 of 10 patients. Average flow increased in 9 of the 10 patients (P < 0.01). Mean rapid phase flow in the control state was 110 ml/100 g per min and after nitroglycerin increased to 132 ml/100 g per min (P < 0.01); slow phase flow increased from 12 ml/100 g per min to 15 ml/100 g per min (P < 0.05). It is concluded that, under these conditions, nitroglycerin improves perfusion in regions of diseased myocardium in patients with coronary artery disease.
Article
Fifteen of 27 patients became hypertensive after unilateral carotid endarterectomy; seven of these experienced neurological deterioration, which persisted more than a week in five patients. Neurological worsening did not occur in patients without postoperative hypertension, which developed primarily in patients with a preoperative disturbance of consciousness or other neurological deficit, especially in those with seizure activity. There was no correlation with preoperative blood pressure, the time of arteriography, arteriographical or operative findings, use of an internal shunt, or other features of operative or anesthetic technique. Serum sodium concentration was significantly lower in hypertensive patients, although fluid administration did not vary in the two patient groups.
Article
Sodium nitroprusside and trimethaphan camsylate often are used to induce hypotension for a variety of surgical procedures. Both agents have a short duration of action that allows for minute-to-minute regulation of blood pressure with rapid restoration of normal pressure. Nitroprusside decreases vascular resistance by directly relaxing arteriolar and, to a lesser extent, venular smooth muscle. Trimethaphan primarily decreases vascular tone by blocking autonomic reflexes secondary to ganglionic blockade. Some direct vasodilatory activity is also present. In a previous report, we described hormonal and hemodynamic changes that occurred using pentoliniumtartrate-induced hypotension for the management of scoliosis surgery. In the present study, we compare the hormonal responses during nitroprusside- or trimethaphan-induced hypotension in a similar group of patients.
Article
Labetalol is a competitive antagonist of alpha 1-, beta 1-, and beta 2-adrenergic receptors. The hemodynamic effects of the drug include reduced blood pressure, heart rate, and peripheral resistance, with little change in resting cardiac output or stroke volume. In open trials and controlled studies, labetalol was an effective antihypertensive. Labetalol compared favorably with beta-blockers alone or in combination with vasodilators, for the treatment of hypertension. Reductions in heart rate are less pronounced with labetalol as compared with propranolol. Labetalol produces rapid reductions in blood pressure when administered intravenously for severe hypertension. The most frequent adverse reactions to the drug include fatigue, postural symptoms, headache, and gastrointestinal complaints. Labetalol may prove advantageous when vasodilation in addition to beta-blockade is desired, or for selected patients experiencing adverse effects attributable to beta-blockade. Until the clinical profile of labetalol is better defined, the use of the drug should be limited.
Article
The cause of hypertension in the immediate postoperative period after carotid endarterectomy is unknown. In order to elucidate the etiology of hypertension following carotid endarterectomy, blood samples were drawn intraoperatively from internal jugular vein and external carotid artery prior to and subsequent to carotid endarterectomy in 20 patients. Renin measurement in these samples produced a ratio of internal jugular vein (cerebral) to external carotid artery (systemic). In pre-endarterectomy samples, this cerebral-to-systemic ratio was 1.0 +/- 0.17. However, in the six patients hypertensive postoperatively, this ratio was significantly (p less than 0.02) higher at 1.39 +/- 0.4 than in 14 patients not hypertensive, 0.99 +/- 0.28. Although this ratio in hypertensive patients reverted to 1.12 +/- 0.24 in the postoperative period, the present study suggests a relation between hypertension after carotid endarterectomy and renin production by the brain.
Article
A prospective study of hypertension first appearing during and after saphenous vein bypass coronary surgery was performed in 28 patients to examine the incidence, hemodynamics and mechanism of this problem. In 15 patients (54 percent) new hypertension developed (mean arterial pressure greater than 107 mm Hg), characterized by increased peripheral vascular resistance and unchanged cardiac output within 1 hour after surgery. These 15 patients had a longer history of angina of greater severity, but also had relatively well preserved ventricular myocardium. Because plasma renin activity was depressed in patients in the hypertensive group, activation of the renin-angiotensin system was not important in the pathogenesis of this postoperative hypertension. The expected decrease in total peripheral resistance at the onset of cardiopulmonary bypass was observed in all patients, but later during bypass the peripheral resistance increased in all patients in association with a rise in plasma epinephrine levels. Patients who had hypertension postoperatively had a greater increase in arterial pressure and total peripheral resistance during cardiopulmonary bypass than did those with normal postoperative blood pressure. An elevation in plasma epinephrine and norepinephrine concentration, suggesting enhanced sympathoadrenal responsiveness to the challenge of cardiopulmonary bypass, was characteristic of the hypertensive group. This evidence of enhanced sympathetic activity during surgery may be a useful predictor of the development of postoperative hypertension.
Article
1 Labetalol 100 mg was given intravenously to 27 patients with essential hypertension (12 males, 15 females; WHO I-II; age range 30-66 yr; on average, a significant reduction of blood pressure was observed within 5 min (P less than 0.001). Average heart rate was also reduced significantly (P less than 0.01). 2 In 18 patients haemodynamic measurements were performed (dye-dilution or thermodilution technique): blood pressure reduction was related to peripheral vasodilatation, as cardiac index remained unmodified. 3 The absolute and percentage decrease of blood pressure, heart rate and total peripheral resistance after labetalol 100 mg intravenously, was significantly greater in the patients with higher baseline plasma noradrenaline concentration values. 4 In 12 out of 27 patients labetalol was given orally for 2 months (dose range 300-1200 mg); the pattern of blood pressure and heart rate changes after oral therapy were comparable to those observed after acute administration of the drug. 5 The degree of blood pressure and heart rate reductions after oral labetalol was also significantly related to pretreatment basal noradrenaline concentration.
Article
Routine coronary angiography has been recommended to all patients undergoing carotid endarterectomy at the Cleveland Clinic since 1978. Patients found to have severe, correctable coronary artery disease (CAD) have been advised to undergo myocardial revascularization as a staged or combined procedure in conjunction with carotid endarterectomy in an attempt to reduce the incidence of fatal myocardial infarction during the postoperative period, and during the late follow-up interval. In order to provide an historic standard with which the results of this approach may eventually be compared, complete follow-up information has been obtained for 95% of 335 consecutive patients who underwent carotid endarterectomy between 1969 and 1973. Fatal myocardial infarction accounted for 60% of early deaths within 30 days of operation and occurred in 1.8% of the entire series. Among the patients who survived operation, the five-year mortality rate was 27%, and the 11-year mortality rate was 48%. Myocardial infarction caused 37% of the deaths that occurred within five years after operation and 38% of the deaths that have occurred within 11 years. Differences in the incidence of fatal myocardial infarction within five years after operation between a group of 116 patients who had no clinical evidence of CAD and a group of 209 patients suspected to have CAD attained statistical significance (p less than 0.1) despite the fact that 67 patients suspected to have CAD eventually underwent myocardial revascularization. Improvement in actuarial survival (p less than 0.05) and reduction in the late mortality rate (p less than 0.01) were statistically significant for the subset of patients with suspected CAD who had aortocoronary bypass graft procedures.
Article
Comparative studies of plasma norepinephrine in patients with essential hypertension and in normotensive controls have consistently reported higher mean resting levels of norepinephrine in the hypertensive groups, but the hypertensive-normotensive differences have often been small and, in about three-fifths of the studies, not statistically significant. The author reviewed the medical literature to test the hypothesis that, during stress, hypertensive-normotensive differences in norepinephrine become more apparent. Among 24 studies involving orthostatic stress, the increment in norepinephrine with standing was similar for hypertensives and normotensives (239 vs 230 pg/ml). In contrast, among eight studies involving exercise, the increment in norepinephrine was significantly greater in hypertensives (834 vs 450 pg/ml). For both standing and isotonic exercise, absolute changes in norepinephrine with stress correlated with basal norepinephrine across the hypertensive but not the normotensive groups. These results are consistent with the existence within the hypertensive population of a subgroup of patients with elevated norepinephrine levels at rest and excessive sympathetic responsiveness to stress. However, the available literature is decidedly lacking in studies about other types of stress besides standing and exercise.
Article
Blood pressure changes following carotid endarterectomy were studied in 39 patients undergoing 42 carotid endarterectomies, in order to establish the incidence of hypertension and to study the use of hydrallazine for its treatment. Hypertension occurred in 28 cases (66%) and was treated with intravenous hydralazine in a dose of 20 +/- 8 mg; this resulted in a systolic blood pressure fall of 46 +/- 22 mmHg, diastolic blood pressure fall of 24 +/- 12 mmHg, mean blood pressure fall of 31 +/- 15 mmHg, and a pulse rate increase of 7 +/- 9 beats per minute. Hydrallazine is a safe, effective drug for the treatment of intraoperative hypertension.
Article
Severe postoperative hypertension following carotid endarterectomy is a serious and poorly understood clinical problem associated with an increased mortality rate and increased incidence of neurologic deficit. This complication, which is defined as a sustained elevation of systolic pressure greater than 200 mm Hg requiring pharmacologic control, occurred following 19% of 253 carotid procedures. Preoperative hypertension is the single most important determinate in the development of postoperative hypertension. The incidence of preoperative hypertension in patients who developed postoperative hypertension was 79.6% to 57.4% in patients who did not develop this complication (P < 0.01). There was a significantly increased incidence of neurologic deficit and operative mortality rate in the group who developed postoperative hypertension. There were five neurologic deficits in the group who developed postoperative hypertension, for an incidence of 10.2%. The incidence of neurologic deficit in the group who did not develop postoperative hypertension was 3.4%. The only deaths were in the postoperative hypertensive group. The hypertensive patient is at greater risk for postoperative hypertension, which is associated with increased neurologic morbidity and mortality.
Hypertension following carotid endarterectomy Smith BL: Hypertension following carotid endar-terectomy: The role of cerebral renin production Goldstein DS: Plasma norepinephrine during stress in essential hypertension
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Satiani B, Vasko JS, Evans WE: Hypertension following carotid endarterectomy. Surg Neurol 11:357-360, 1979 27, Smith BL: Hypertension following carotid endar-terectomy: The role of cerebral renin production. J Vase Surg 1:623-627, 1984 28, Goldstein DS: Plasma norepinephrine during stress in essential hypertension. Hypertension 3:551-556, 1981
Pathogen-esis of paroxysmal hypertension developing during and after coronary bypass surgery: A study of hemodynamic and humoral factors
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Wallach R, Karp RB, Reves JG, et al: Pathogen-esis of paroxysmal hypertension developing during and after coronary bypass surgery: A study of hemodynamic and humoral factors. Am J Cardio146:559-665, 1980
Effects of labetalol on plasma renin, aldosterone, and catecholamines in hypertensive patients The acute and chronic hypotensive effect of labetalol and the relationship with pre-treatment plasma noradrenaline levels
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Lijnen P J, Amery AK, Fagard RH, et al: Effects of labetalol on plasma renin, aldosterone, and catecholamines in hypertensive patients. J Cardiovasc Pharmacol 1:625-632, 1979 31. Agabiti-Rosei E, Alicandri CL, Beschi M, et al: The acute and chronic hypotensive effect of labetalol and the relationship with pre-treatment plasma noradrenaline levels. Br J Clin Pharmaeol 13:87S-92S, 1982