Effects of nicardipine on cerebral vascular responses to hypocapnia and blood flow velocity in the middle cerebral artery

Paradoxical cerebrovascular hemodynamic changes with nicardipine

OBJECTIVE

Intravenous nicardipine is commonly used for blood pressure reduction in patients with acute stroke. However, few studies have described its effects on cerebrovascular hemodynamics as measured by transcranial Doppler (TCD) waveform analysis and pulsatility index (PI). In this study, the authors report examples of a consistent but paradoxical finding associated with nicardipine that suggests intracranial vasoconstriction, contrary to what is expected from a vasodilator.

METHODS

The data presented are from a convenience sample of patients who underwent TCD monitoring before, after, or during nicardipine administration. In each case, TCD waveform morphologies and PIs were compared.

RESULTS

The TCD waveforms during nicardipine infusion are characterized by a prominent systolic peak and dicrotic notch. Systolic deceleration was more pronounced and PIs were significantly elevated in patients who were on nicardipine (p < 0.001). This finding was not evident when patients were not on nicardipine.

CONCLUSIONS

This study provides the first evidence of paradoxical intracranial vasoconstriction associated with intravenous nicardipine. In the authors' experience, this finding is consistently encountered in the vast majority of patients who are treated with intravenous nicardipine, and is contradictory to what is expected from a vasodilator. Future studies are needed to confirm this finding in larger populations and diverse clinical settings and to examine mechanisms that explain this phenomenon.

The Effect of Clevidipine on Cerebral Blood Flow Velocity and Carbon Dioxide Reactivity in Human Volunteers

BACKGROUND

Clevidipine is a short acting, esterase metabolized, calcium channel antagonist administered as a continuous infusion for control of hypertension. Its profile allows for rapid titration and may be uniquely suited to achieving tight hemodynamic targets in neurosurgical and neurocritical care patients. The present study was designed to investigate the effect of clevidipine infusion on cerebral blood flow and cerebral CO2 responsiveness as measured by cerebral blood flow velocity (CBFV) using transcranial Doppler.

MATERIALS AND METHODS

CBFV was continuously recorded in 5 healthy subjects during the following conditions: baseline 1 (BL1); baseline with hyperventilation (HV1); baseline 2 (BL2); clevidipine infusion to achieve 15% mean arterial pressure (MAP) reduction (C15); clevidipine infusion to achieve 30% MAP reduction (C30); clevidipine infusion to 30% MAP reduction with hyperventilation (HV2).

RESULTS

The mean CBFV during intermediate (C15) or maximum (C30) dose clevidipine infusion was unchanged compared with baseline (BL2) (F2,8=0.66; P=0.54). Cerebral CO2 reactivity, expressed as %[INCREMENT]CBFV/[INCREMENT]mm Hg CO2, was not significantly different in the presence of maximal-dose clevidipine (HV2) as compared with baseline (HV1) (1.6±0.4 vs. 1.6±0.3%[INCREMENT]CBFV/[INCREMENT]mm Hg CO2, P=0.73).

CONCLUSIONS

Clevidipine infusion did not significantly increase CBFV nor was cerebral CO2 reactivity reduced during maximal-dose clevidipine infusion. Further systematic investigation of clevidipine in patients with central nervous system pathology seems justified.

The comparative effects of equipotent Bispectral Index dosages of propofol and sevoflurane on cerebrovascular carbon dioxide reactivity in elderly patients

STUDY OBJECTIVES

To compare the effects of equipotent Bispectral Index (BIS) doses of propofol and sevoflurane on cerebrovascular carbon dioxide (CO(2)) reactivity in elderly patients.

DESIGN

Prospective, randomized, controlled study.

SETTING

University Hospital.

PATIENTS

30 consecutive elderly patients (older than 70 yrs of age) scheduled for elective orthopedic, cardiac, or thoracic surgery.

INTERVENTIONS

Anesthesia was maintained with either sevoflurane or propofol along with 33% oxygen and 67% nitrous oxide. A BIS monitor was used. Sevoflurane and propofol dosages were controlled to maintain BIS values at target levels of 40-45.

MEASUREMENTS

A 2.5-MHz pulsed transcranial Doppler (TCD) probe was used to measure mean blood flow velocity in the middle cerebral artery (Vmca). After establishing baseline values of Vmca, end-tidal CO(2) was increased by decreasing ventilatory frequency by 4-8 breaths/min.

MAIN RESULTS

Equipotent doses of 2.25% sevoflurane and 6.61 mg/kg/hr of propofol were required to maintain BIS values at target levels. Baseline blood pressure (BP), BP at hypercapnia, baseline PaCO(2), baseline PaCO(2) at hypercapnia, and pulsatile index were essentially identical between the groups. Absolute and relative CO(2) reactivities in the sevoflurane groups were higher than those in the propofol groups (absolute CO(2) reactivity: 3.2 +/- 0.2* vs. 2.2 +/- 0.3 cm/sec/mmHg; relative CO(2) reactivity: 9.4 +/- 0.3* vs. 7.8 +/- 0.3 cm/sec/mmHg; *P < 0.01 vs. propofol group).

CONCLUSIONS

In elderly patients, hypercapnia has less effect on cerebral circulation during propofol anesthesia than with sevoflurane.

Nicardipine: a hypotensive dihydropyridine-type calcium antagonist with a peculiar cerebrovascular profile

Control of blood pressure protects against the development of cerebrovascular lesions, stroke, and vascular dementia (VaD). Cerebrovascular disease is increasingly recognized as a cause of cognitive impairment and dementia primarily in the elderly. Nicardipine is a dihydropyridine-type calcium channel blocker (CCB) with a peculiar cerebrovascular profile developed approximately 30 years ago. This study has reviewed the main controlled clinical studies investigating the use of nicardipine in pathologies associated with cerebrovascular injury, such as subarachnoid haemorrhage (SAH), acute stroke, and VaD. SAH is a main cerebrovascular indication of CCBs. In this indication, CCBs prevent vasospasm and improve clinical outcomes. Nimodipine represents the CCB more investigated in this indication. Former studies did not demonstrate a clear advantage of nicardipine versus nimodipine in SAH. A more recent approach using implants of nicardipine prolonged-release showed a decreased incidence of vasospasm, delayed ischemic deficits, and improved clinical outcome after severe SAH. Controlled trials have shown the effectiveness of the drug in preventing stroke. Increasing evidence suggests some benefit of some CCBs in VaD or mixed degenerative and vascular dementia. In this setting, nicardipine has been investigated in approximately 6,000 patients, with an improvement of cognitive deterioration in more than 60% of patients treated. The pronounced anti-hypertensive activity of nicardipine and its safety and effectiveness in cognitive domain suggest its reconsideration in the treatment of cognitive impairment of vascular origin as well as for reducing the risk of recurrent stroke in patients at high risk of it.

Risks and benefits of deliberate hypotension in anaesthesia: a systematic review

This systematic review was performed to investigate and review the evidence on the risks and benefits of hypotensive anaesthesia in order to answer the following question: 'Should deliberate hypotension be used routinely during orthognathic surgery?' An electronic search on MEDLINE and the Cochrane Library database was carried out for all relevant articles using specific search keywords. All articles were classified by their levels of evidence. Studies with highest level of evidence and rated to have the lowest risk of bias were reviewed. Regarding the benefits of hypotensive anaesthesia, three studies reported significant decrease of blood loss in patients receiving hypotensive anaesthesia. Two studies reported a significant decrease in transfusion rate. Two studies demonstrated improved surgical field and significant reduction in operation time. In terms of risk, no significant changes in cerebral, cardiovascular, renal and hepatic functions in patients receiving hypotensive anaesthesia compared to control were reported. In conclusion, hypotensive anaesthesia appears to be effective in reducing blood loss. Serious consequences due to organ hypoperfusion are uncommon. Hypotensive anaesthesia can be justified as a routine procedure for orthognathic surgery especially bimaxillary osteotomy. Patient selection and appropriate monitoring are mandatory for this technique to be carried out safely.

The comparative effects of sevoflurane versus isoflurane on cerebrovascular carbon dioxide reactivity in patients with previous stroke

PURPOSE

The use of volatile anesthetics is reportedly related to altered cerebrovascular carbon dioxide (CO2) reactivity. We examined the comparative effects of sevoflurane versus isoflurane on cerebrovascular CO2 reactivity in patients with previous stroke.

METHODS

Twenty-four patients with previous stroke and 20 patients without previous stroke (serving as controls) were studied. Anesthesia was maintained with either end-tidal 1.0 minimum alveolar concentration (MAC) sevoflurane or 1.0 MAC isoflurane in 33% oxygen and 67% nitrous oxide. A 2.5-MHz pulsed transcranial Doppler (TCD) probe was attached to the patient's head at the right or left temporal window for continuous measurement of mean blood flow velocity in the middle cerebral artery (Vmca). After establishing baseline values of Vmca and cardiovascular hemodynamics, we increased end-tidal CO2 by decreasing the ventilatory frequency by 2-5 breaths x min(-1).

RESULTS

We found that values for absolute and relative CO2 reactivity in the sevoflurane groups were lower than those in the isoflurane groups (absolute CO2 reactivity in the sevoflurane groups: control, 3.3 +/- 0.4*; previous stroke, 3.4 +/- 0.4*; absolute CO2 reactivity in the isoflurane groups: control, 4.2 +/- 0.3; previous stroke, 4.5 +/- 0.4, cm x s(-1) x mmHg(-1); *P < 0.05 compared with isoflurane group). There were no significant differences in the values for absolute and relative CO2 reactivity between the controls and the previous-stroke patients within each of the sevoflurane and isoflurane groups.

CONCLUSION

Our findings suggest that, in patients with previous stroke, cerebrovascular CO2 reactivity under sevoflurane anesthesia was lower than that under isoflurane anesthesia.

Effects of nicardipine-induced hypotension on cerebrovascular carbon dioxide reactivity in patients with diabetes mellitus under sevoflurane anesthesia

PURPOSE

The purpose of this study was to examine the effects of nicardipine-induced hypotension on cerebrovascular CO2 reactivity in patients with diabetes mellitus under sevoflurane anesthesia.

METHODS

Nineteen diabetic patients, and 11 nondiabetic patients (serving as controls), undergoing elective orthopedic, cardiovascular, or thoracic surgery were included in the study. The diabetic patients were divided into three groups according to the antidiabetic therapy they were receiving, i.e., diet therapy (n = 6), oral antidiabetic drugs (n = 7), and insulin (n = 6). Anesthesia was maintained with 1.0 minimum alveolar concentration of sevoflurane. Absolute and relative cerebrovascular CO2 reactivity was calculated using a 2.5-MHz pulsed transcranial Doppler (TCD) probe for the continuous measurement of mean blood flow velocity in the middle cerebral artery (Vmca). The cerebrovascular CO2 reactivity was measured both at baseline and during hypotension by increasing the ventilatory frequency by 4 to 7 breaths.min(-1). Nicardipine was used to induce hypotension.

RESULTS

We found that values for the Bispectral index (BSI), baseline mean blood pressure, endtidal CO2 (Pet(CO2)), and Vmca were essentially identical in all patients, irrespective of the type of antidiabetic treatment being taken. Values for absolute and relative CO2 reactivity in insulin-dependent patients, at both baseline blood pressure and during hypotension, were lower than those in patients in the antidiabetic drug, diet, and control groups (during hypotension, absolute CO2 reactivity: diet group: 3.2 +/- 0.9; oral antidiabetic drug group: 3.2 +/- 0.7; insulin group: 1.5 +/- 0.6; control group: 3.4 +/- 0.8 cm.s(-1).mmHg(-1), [P < 0.05 insulin group vs the other groups]; relative CO2 reactivity: diet group, 6.3 +/- 1.0; oral antidiabetic drug group, 6.5 +/- 0.8; insulin group, 3.5 +/- 0.8; control group, 6.5 +/- 0.7%.mmHg(-1), [P < 0.05 insulin group vs the other groups].

CONCLUSION

We concluded that cerebrovascular CO2 reactivity in insulin-dependent patients is impaired during nicardipine-induced hypotension under sevoflurane anesthesia.

The use of nicardipine for electroconvulsive therapy: a dose-ranging study

A wide variety of vasoactive drugs have been used to treat the acute hypertensive response to electroconvulsive therapy (ECT). We designed this randomized, double-blind, saline-controlled, crossover study to compare three different doses of nicardipine when administered before the ECT stimulus. Twenty-five patients undergoing a series of 4 ECT treatments received bolus injections of either saline or nicardipine 20, 40, or 80 mug/kg IV in a random sequence during a standardized methohexital (1 mg/kg) and succinylcholine (1 mg/kg) anesthetic technique. The mean arterial blood pressure (MAP) and heart rate values were recorded at specific time intervals, as were the duration of seizure activity and the need for rescue labetalol. Both the 40 and 80 mug/kg doses of nicardipine reduced the percentage increase in MAP above the baseline value compared with the saline group (7% and 7% versus 30%, respectively). Nicardipine 40 and 80 mug/kg were also associated with a significant reduction in the need for labetalol (7 +/- 3 mg and 5 +/- 0 mg versus 22 +/- 10 mg in the saline group). Compared with the 40 mug/kg dose, nicardipine 80 mug/kg was associated with a more rapid heart rate at the time the ECT stimulus was applied. The 80 mug/kg dose was also associated with a reduced MAP value on awakening compared with the baseline value (91 +/- 12 mm Hg versus 102 +/- 8 mm Hg). We conclude that a bolus injection of nicardipine 40 mug/kg IV immediately before the ECT stimulus was optimal for controlling the acute hemodynamic response to ECT treatments.

Prediction and monitoring of cerebral hyperperfusion after carotid endarterectomy by using single-photon emission computerized tomography scanning

OBJECT

The purpose of this study was to determine whether the preoperative measurement of acetazolamide-induced changes in cerebral blood flow (CBF), which is performed using single-photon emission computerized tomography (SPECT) scanning, can be used to identify patients at risk for hyperperfusion following carotid endarterectomy (CEA). In addition, the authors investigated whether monitoring of CBF with SPECT scanning after CEA can be used to identify patients at risk for hyperperfusion syndrome.

METHODS

Cerebral blood flow and cerebrovascular reactivity (CVR) to acetazolamide were measured before CEA in 51 patients with ipsilateral internal carotid artery stenosis (> or = 70% stenosis). Cerebral blood flow was also measured immediately after CEA and on the 3rd postoperative day. Hyperperfusion (an increase in CBF of > or = 100% compared with preoperative values) was observed immediately after CEA in eight of 12 patients with reduced preoperative CVR. Reduced preoperative CVR was the only significant independent predictor of post-CEA hyperperfusion. Forty-three patients in whom hyperperfusion was not detected immediately after CEA did not exhibit hyperperfusion on the 3rd postoperative day and did not experience hyperperfusion syndrome. In two of eight patients in whom hyperperfusion occurred immediately after CEA, CBF progressively increased and hyperperfusion syndrome developed, but intracerebral hemorrhage did not occur. In the remaining six of eight patients in whom hyperperfusion was detected immediately after CEA, the CBF progressively decreased and the hyperperfusion resolved by the 3rd postoperative day.

CONCLUSIONS

Preoperative measurement of acetazolamide-induced changes in CBF, which is performed using SPECT scanning, can be used to identify patients at risk for hyperperfusion after CEA. In addition, post-CEA monitoring of CBF performed using SPECT scanning results in the timely and reliable identification of patients at risk for hyperperfusion syndrome.

The comparative effects of prostaglandin E1 and nicardipine on cerebral microcirculation in rabbits

We compared the effects of the systemic hypotensive drugs prostaglandin E1 (PGE1) and nicardipine on the cerebral microcirculation and on the cerebrovascular reactivities to hypercapnia and hypoxia. In isoflurane-anesthetized rabbits (n = 48), we measured cerebral pial vessel diameters using a cranial-window preparation: (a) during IV PGE1- or nicardipine-induced mild or moderate hypotension (to 80% or 60% of initial mean arterial blood pressure), (b) after topical administration of these drugs, and (c) during hypercapnia or hypoxia induced during such mild or moderate hypotension. Pial arteriolar diameters were (a) unchanged when hypotension (mild or moderate) was induced by PGE1 but increased when it was induced by nicardipine and (b) increased dose-dependently by topical administration of nicardipine but not PGE1. Only small changes in cerebral venular diameter were observed in these experiments. The pial arteriolar dilator response to hypercapnia was potentiated during hypotension (mild or moderate) when it was induced by PGE1 but decreased when it was induced by nicardipine, whereas the response to hypoxia was maintained during PGE1-induced hypotension but decreased during nicardipine-induced hypotension. In conclusion, as a systemic hypotensive drug, PGE1 does not dilate cerebral arterioles and maintains cerebrovascular reactivities to hypercapnia and hypoxia, whereas nicardipine dilates such vessels and reduces these cerebrovascular reactivities.

IMPLICATIONS

When given systemically to produce mild or moderate hypotension, prostaglandin E1 does not induce cerebral vasodilation and maintains cerebrovascular reactivity to hypercapnia and hypoxia, whereas nicardipine dilates cerebral vessels and reduces both reactivities.

The effects of nicardipine on dynamic cerebral autoregulation in patients anesthetized with propofol and fentanyl

We investigated the effects of nicardipine on dynamic cerebral pressure autoregulation in 13 normal adult patients undergoing gynecologic or orthopedic surgery. Anesthesia was induced and maintained with propofol and fentanyl. Hypotension to a mean arterial pressure of 60-65 mm Hg was induced and maintained with a continuous infusion of nicardipine. Time-averaged mean blood flow velocity in the right middle cerebral artery was measured continuously by using transcranial Doppler ultrasonography. The cerebral autoregulatory responses were activated by releasing thigh cuffs. The actual blood flow velocity in the right middle cerebral artery response to acute change in mean arterial pressure was fitted to 1 of 10 computer-generated curves to determine the dynamic rate of cerebral autoregulation (dRoR), and the best fitting curve was used. The autoregulation test was repeated until two values of dRoR were obtained at baseline and during induced hypotension. Nicardipine significantly reduced dRoR values of 13.1% +/- 3.6%/s at baseline to 8.3% +/- 2.6%/s during hypotension (P: < 0.01). During deliberate hypotension induced by nicardipine, the cerebral dynamic autoregulatory response is impaired in normal adult patients.

IMPLICATIONS

During deliberate hypotension induced by nicardipine, the cerebral dynamic autoregulatory response is impaired in normal adult patients.

Reduction of cerebral hyperemia with anti-hypertensive medication after electroconvulsive therapy

PURPOSE

Several different anti-hypertensive regimens have been introduced for the prevention of systemic hyperdynamic responses after electrically induced seizures. In the present study, the effects of anti-hypertensive medications on cerebral circulation were studied.

METHODS

Systemic blood pressure was controlled by several anti-hypertensive medications, nicardipine, prostaglandin EI, alprenolol and nitroglycerin, in 30 patients (150 electroconvulsive therapy trials). Changes in cerebral blood flow velocity were measured by transcranial Doppler sonography of the right middle cerebral artery from the start of anesthesia to 10 min after the electrical shock.

RESULTS

Administration of a Ca2+ antagonist, nicardipine, or prostaglandin EI did not alter the augmented cerebral blood flow velocity after the seizure. However, a beta-adrenergic blocking agent, alprenolol (P<0.05) or nitroglycerin (P<0.01) partially inhibited the increase in cerebral blood flow velocity. Maximal blood flow velocity was 133% larger than the pre-anesthesia value in the control group, 109% in the nicardipine group, 113% in the prostaglandin EI group, 72% in the alprenolol group, and 45% in the nitroglycerin group, respectively. The increase in cerebral blood flow velocity after electrically induced seizure was independent of systemic blood pressure. Internal jugular venous saturation (SjO2) was increased, and difference in arterial and venous concentrations of lactate was not altered in all groups.

CONCLUSIONS

Cerebral hemodynamics is altered by ECT, even when systemic hemodynamics are stabilized by antihypertensive medication. Although the effects of antihypertensive medicine on cerebral hemodynamics are variable, systemic blood pressure control by these agents does not induce cerebral ischemia after ECT.

Effects of nicardipine-, nitroglycerin-, and prostaglandin E1-induced hypotension on human cerebrovascular carbon dioxide reactivity during propofol-fentanyl anesthesia

STUDY OBJECTIVE

To investigate the effects of nicardipine-, nitroglycerin-, and prostaglandine E1-induced hypotension on cerebrovascular carbon dioxide (CO2) reactivity over a wide range of arterial CO2 tension (PaCO2) (PaCO2; range 25 to 50 mmHg).

DESIGN

Prospective, randomized study.

SETTING

Operating room of a university-affiliated hospital.

PATIENTS

36 ASA physical status I and II patients without cerebrovascular disease, hypertension, or diabetes mellitus, undergoing an elective abdominal surgery.

INTERVENTIONS

Patients were randomly allocated to one of three groups (nicardipine-, nitroglycerin-, or prostaglandin E1-induced hypotension group; 12 in each group). Anesthesia was induced and maintained with a bolus dose, followed by a continuous infusion of propofol (6.7 +/- 1.5 mg/kg/hr) and fentanyl (1.68 +/- 0.4 micrograms/kg/hr). Deliberate hypotension of mean arterial pressure 55 to 60 mmHg was induced and maintained with a bolus dose, followed by a continuous infusion of nicardipine (6.80 +/- 0.75 micrograms/kg/min), nitroglycerin (3.20 +/- 1.10 micrograms/kg/min), or prostaglandin E1 (0.103 +/- 0.052 microgram/kg/min).

MEASUREMENTS AND MAIN RESULTS

Time-averaged mean red blood cell velocity in the right middle cerebral artery (Vmca) at PaCO2 ranging from 25 to 50 mmHg was measured with transcranial Doppler ultrasonography. A minimum of six simultaneous measurements of Vmca and PaCO2 were obtained during baseline and deliberate hypotension in each patient. Absolute slope between Vmca and PaCO2 during baseline and deliberate hypotension was determined individually by linear regression analysis. Absolute slope was treated as the variable, because it yielded a significant close correlation coefficient (r > 0.95; p < 0.05). Comparisons between baseline and deliberate hypotension were made by analysis of variance for repeated measures. Mean absolute slope was significantly reduced from 1.88 +/- 0.57 cm/sec/mmHg (mean +/- SD) to 1.21 +/- 0.46 in the nicardipine group (p < 0.05), from 1.75 +/- 0.69 to 1.35 +/- 0.47 in the nitroglycerin group (p < 0.05), and from 1.95 +/- 0.89 to 1.33 +/- 0.70 (p < 0.05) in the prostaglandin E1 group, respectively.

CONCLUSION

Nicardipine-, nitroglycerin-, and prostaglandin E1-induced hypotension attenuate the human cerebrovascular CO2 reactivity during propofol-fentanyl anesthesia.

Effect of nicardipine on cerebral blood flow in hypertensive patients with internal carotid artery occlusion: a PET study

PURPOSE

The objective of this study was to elucidate the effect of intravenous administration of nicardipine on the cerebral blood flow of hypertensive patients with internal carotid artery occlusion (ICAO).

PATIENTS AND METHODS

Six patients with ICAO and 10 normal individuals were examined by positron emission tomography. The cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral metabolic rate of oxygen, oxygen extraction fraction (OEF) and CBF/CBV ratio were evaluated for each vascular territory and each hemisphere, and the interhemispheric asymmetry index of each parameter was also calculated. Nicardipine was administered intravenously to each patient, and the changes in CBF (DeltaCBF%) and in blood pressure (DeltaBP) were examined.

RESULTS

After the administration of nicardipine, the CBF was significantly increased in the patient hemisphere and was unchanged in the occluded hemisphere. Stepwise regression analysis disclosed that the DeltaBP and asymmetry index of OEF were significantly correlated with the DeltaCBF% in the occluded hemisphere.

CONCLUSIONS

These results suggest that CBF is unchanged or increased in ICAO patients after nicardipine administration, but that excessive reduction of blood pressure may lead to CBF decrease in the patients with marked hemodynamic imbalance between the occluded and patent hemispheres. These results suggest that it is advisable not to reduce blood pressure excessively in these patients in the treatment of perioperative or acute hypertension with calcium antagonist.

Nicardipine and treatment of cerebrovascular diseases with particular reference to hypertension-related disorders

Nicardipine is a second generation dihydropyridine-type Ca2+ antagonist with high vascular selectivity and strong cerebral and coronary vasodilatory activity. The compound is used in the treatment of hypertension, primarily in the elderly. In this review the main evidence of the cerebrovascular activity of nicardipine in preclinical studies using in vitro and in vivo models is detailed. A particular physico-chemical property of nicardipine is the almost complete protonation in acid environment. This allows its accumulation in ischemic brain regions and makes it a candidate for the treatment of cerebrovascular disorders characterised by impaired brain perfusion. The main clinical data on the use of nicardipine in cerebral ischemia and related disorders, subarachnoid haemorrhage and stroke, are also reviewed. These studies included 5940 patients affected by chronic cerebrovascular insufficiency (cerebral ischemia, cerebral atherosclerosis mainly associated with hypertension, transient ischemic attacks, sequelae of cerebral infarction, thrombosis or embolia, hypertensive encephalopathy), 1540 patients affected by sequelae of subarachnoid haemorrhage and 206 patients affected by stroke. Both preclinical studies and clinical trials have shown that nicardipine is a safe Ca2+ antagonist with powerful cerebrovascular activity. This suggests its possible use in cerebrovascular disorders in which blockade of Ca2+ channels of the L-type and/or selective cerebral vasodilatation is desirable. Further studies are necessary to establish if modulation of neuronal Ca2+ channels of the L-type by nicardipine may have a neuroprotective effect independent by the cerebrovascular activity of the compound.