Effect of vasodilation by milrinone, a phosphodiesterase III inhibitor, on vasospastic arteries after a subarachnoid hemorrhage in vitro and in vivo: effectiveness of cisternal injection of milrinone

Cisternal nicardipine for prevention of delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage: a comparative retrospective cohort study

PURPOSE

Intrathecal vasoactive drugs have been proposed in patients with aneurysmal subarachnoid hemorrhage (aSAH) to manage cerebral vasospasm (CV). We analyzed the efficacy of intracisternal nicardipine compared to intraventricular administration to a control group (CG) to determine its impact on delayed cerebral ischemia (DCI) and functional outcomes. Secondary outcomes included the need for intra-arterial angioplasties and the safety profile.

METHODS

We performed a retrospective analysis of prospectively collected data of all adult patients admitted for a high modified Fisher grade aSAH between January 2015 and April 2022. All patients with significant radiological CV were included. Three groups of patients were defined based on the CV management: cisternal nicardipine (CN), ventricular nicardipine (VN), and no intrathecal nicardipine (control group).

RESULTS

Seventy patients met the inclusion criteria. Eleven patients received intracisternal nicardipine, 18 intraventricular nicardipine, and 41 belonged to the control group. No cases of DCI were observed in the CN group (p = 0.02). Patients with intracisternal nicardipine had a reduced number of intra-arterial angioplasties when compared to the control group (p = 0.03). The safety profile analysis showed no difference in complications across the three groups. Intrathecal (ventricular or cisternal) nicardipine therapy improved functional outcomes at 6 months (p = 0.04) when compared to the control group.

CONCLUSION

Administration of intrathecal nicardipine for moderate to severe CV reduces the rate of DCI and improved long-term functional outcomes in patients with high modified Fisher grade aSAH. This study also showed a relative benefit of cisternal over intraventricular nicardipine, thereby reducing the number of angioplasties performed in the post-treatment phase. However, these preliminary results should be confirmed with future prospective studies.

The Role of Cisternostomy and Cisternal Drainage in the Treatment of Aneurysmal Subarachnoid Hemorrhage: A Comprehensive Review

Aneurysmal subarachnoid hemorrhage (aSAH) provokes a cascade reaction that is responsible for early and delayed brain injuries mediated by intracranial hypertension, hydrocephalus, cerebral vasospasm (CV), and delayed cerebral ischemia (DCI), which result in increased morbidity and mortality. During open microsurgical repair, cisternal access is achieved essentially to gain proximal vascular control and aneurysm exposition. Cisternostomy also allows brain relaxation, removal of cisternal clots, and restoration of the CSF dynamics through the communication between the anterior and posterior circulation cisterns and the ventricular system, with the opening of the Membrane of Liliequist and lamina terminalis, respectively. Continuous postoperative CSF drainage through a cisternal drain (CD) is a valuable option for treating acute hydrocephalus and intracranial hypertension. Moreover, it efficiently removes the blood and toxic degradation products, with a potential benefit on CV, DCI, and shunt-dependent hydrocephalus. Finally, the CD is an effective pathway to administer vasoactive, fibrinolytic, and anti-oxidant agents and shows promising results in decreasing CV and DCI rates while minimizing systemic effects. We performed a comprehensive review to establish the adjuvant role of cisternostomy and CD performed in cases of direct surgical repair for ruptured intracranial aneurysms and their role in the prevention and treatment of aSAH complications.

Treatment of Subarachnoid Hemorrhage-associated Delayed Cerebral Ischemia With Milrinone: A Review and Proposal

Delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage continues to be associated with high levels of morbidity and mortality. This complication had long been thought to occur secondary to severe cerebral vasospasm, but expert opinion now favors a multifactorial etiology, opening the possibility of new therapies. To date, no definitive treatment option for DCI has been recommended as standard of care, highlighting a need for further research into potential therapies. Milrinone has been identified as a promising therapeutic agent for DCI, possessing a mechanism of action for the reversal of cerebral vasospasm as well as potentially anti-inflammatory effects to treat the underlying etiology of DCI. Intra-arterial and intravenous administration of milrinone has been evaluated for the treatment of DCI in single-center case series and cohorts and appears safe and associated with improved clinical outcomes. Recent results have also brought attention to the potential outcome benefits of early, more aggressive dosing and titration of milrinone. Limitations exist within the available data, however, and questions remain about the generalizability of results across a broader spectrum of patients suffering from DCI. The development of a standardized protocol for milrinone use in DCI, specifically addressing areas requiring further clarification, is needed. Data generated from a standardized protocol may provide the impetus for a multicenter, randomized control trial. We review the current literature on milrinone for the treatment of DCI and propose a preliminary standardized protocol for further evaluation of both safety and efficacy of milrinone.

Cardiac Output and Cerebral Blood Flow: A Systematic Review of Cardio-Cerebral Coupling

Control of cerebral blood flow (CBF) is crucial to the management of neurocritically ill patients. Small studies which have examined the role of cardiac output (CO) as a determinant of CBF have inconsistently demonstrated evidence of cardio-cerebral coupling. Putative physiological mechanisms underpinning such coupling include changes in arterial blood pressure pulsatility, which would produce vasodilation through increased oscillatory wall-shear-stress and baroreceptor mediated reflex sympatholysis, and changes in venous backpressure which may improve cerebral perfusion pressure. We sought to summarize and contextualize the literature on the relationship between CO and CBF and discuss the implications of cardio-cerebral coupling for neurocritical care. A systematic review of the literature yielded 41 studies; all were of low-quality and at high-risk of bias. Results were heterogenous, with evidence for both corroboration and confutation of a relationship between CO and CBF in both normal and abnormal cerebrovascular states. Common limitations of studies were lack of instantaneous CBF measures with reliance on transcranial Doppler-derived blood flow velocity as a surrogate, inability to control for fluctuations in established determinants of CBF (eg, PaCO2), and direct effects on CBF by the interventions used to alter CO. Currently, the literature is insufficiently robust to confirm an independent relationship between CO and CBF. Hypothetically, the presence of cardio-cerebral coupling would have important implications for clinical practice. Manipulation of CBF could occur without the risks associated with extremes of arterial pressure, potentially improving therapy for those with cerebral ischemia of various etiologies. However, current literature is insufficiently robust to confirm an independent relationship between CO and CBF, and further studies with improved methodology are required before therapeutic interventions can be based on cardio-cerebral coupling.

Intravenous milrinone for treatment of delayed cerebral ischaemia following subarachnoid haemorrhage: a pooled systematic review

Small trials have demonstrated promising results utilising intravenous milrinone for the treatment of delayed cerebral ischaemia (DCI) after subarachnoid haemorrhage (SAH). Here we summarise and contextualise the literature and discuss the future directions of intravenous milrinone for DCI. A systematic, pooled analysis of literature was performed in accordance with the PRISMA statement. Methodological rigour was analysed using the MINORS criteria. Extracted data included patient population; treatment protocol; and clinical, radiological, and functional outcome. The primary outcome was clinical resolution of DCI. Eight hundred eighteen patients from 10 single-centre, observational studies were identified. Half (n = 5) of the studies were prospective and all were at high risk of bias. Mean age was 52 years, and females (69%) outnumbered males. There was a similar proportion of low-grade (WFNS 1-2) (49.7%) and high-grade (WFNS 3-5) (50.3%) SAH. Intravenous milrinone was administered to 523/818 (63.9%) participants. Clinical resolution of DCI was achieved in 375/424 (88%), with similar rates demonstrated with intravenous (291/330, 88%) and combined intra-arterial-intravenous (84/94, 89%) therapy. Angiographic response was seen in 165/234 (71%) receiving intravenous milrinone. Hypotension (70/303, 23%) and hypokalaemia (31/287, 11%) were common drug effects. Four cases (0.5%) of drug intolerance occurred. Good functional outcome was achieved in 271/364 (74%) patients. Cerebral infarction attributable to DCI occurred in 47/250 (19%), with lower rates in asymptomatic spasm. Intravenous milrinone is a safe and feasible therapy for DCI. A signal for efficacy is demonstrated in small, low-quality trials. Future research should endeavour to establish the optimal protocol and dose, prior to a phase-3 study.

Protective effect of unilateral vasospasm in the setting of HHH-associated posterior reversible encephalopathy syndrome: case report, review of the literature, and treatment considerations

Background

Hyperdynamic therapy, also called triple-H therapy, is the standard treatment and prophylaxis for aneurysmal-associated vasospasm. In patients who are able to tolerate cardiopulmonary stressors induced by this therapy, it is of benefit as a modality for prevention and treatment of delayed ischemic neurologic deficit. However, it can be a cause of significant cardiopulmonary or neurologic sequelae. In rare cases, it can be associated with posterior reversible encephalopathy syndrome (PRES), secondary to prolonged vasopressor and hypertensive therapies.

Case presentation

We present the case of a patient with right-sided aneurysmal-associated vasospasm who, after 10 days of triple-H therapy, experienced a seizure and was found to have left-sided PRES. Right-sided vasospasm served as a protective mechanism from triple-H therapy-associated PRES. It presented a treatment conundrum due to contradictory perfusion requirements. Hypertensive therapy was curtailed and in efforts to preserve local cerebral perfusion and vasodilation, local therapy with intrathecal nicardipine was initiated. We present our case, a review of the literature, and management considerations.

Conclusions

Therapies that have conventionally functioned as second line treatments for aneurysmal subarachnoid hemorrhage (intra-arterial vasodilators and intrathecal vasodilators) may be beneficial as earlier treatments in the setting of vasospasm given the systemic difficulties and complications associated with HHH therapy in patients with PRES.

[Effect of magnesium sulphate and milrinone on cerebral vasospasm after aneurysmal subarachnoid hemorrhage: a randomized study]

BACKGROUND

Aneurysmal subarachnoid hemorrhage is an important cause of premature death and disability worldwide. Magnesium sulphate is shown to have a neuroprotective effect and it reverses cerebral vasospasm. Milrinone is also used in the treatment of cerebral vasospasm. The aim of the present study was to compare the effect of prophylactic magnesium sulphate and milrinone on the incidence of cerebral vasospasm after subarachnoid hemorrhage.

METHODS

The study included 90 patients with aneurysmal subarachnoid hemorrhage classified randomly (by simple randomization) into two groups: magnesium sulphate was given as an infusion of 500mg.day^-1 without loading dose for 21 days. Group B: milrinone was given as an infusion of 0.5μg.kg^-1.min^-1 without loading dose for 21 days. The cerebral vasospasm was diagnosed by mean cerebral blood flow velocity in the involved cerebral artery (mean flow velocity≥120cm.s^-1), neurological deterioration by Glasgow coma scale, or angiography (the decrease in diameter of the involved cerebral artery >25%).

RESULTS

The mean cerebral blood flow velocity decreased significantly in the magnesium group compared to milrinone group through Day 7, Day 14 and Day 21 (p<0.001). The incidence of cerebral vasospasm decreased significantly with magnesium compared to milrinone (p=0.007). The Glasgow coma scale significantly improved in the magnesium group compared to milrinone group through Day 7, Day 14 and Day 21 (p=0.036, p=0.012, p=0.016, respectively). The incidence of hypotension was higher with milrinone than magnesium (p=0.012).

CONCLUSIONS

The incidence of cerebral vasospasm after aneurysmal subarachnoid hemorrhage was significantly lower and Glasgow coma scale significantly better with magnesium when compared to milrinone. Milrinone was associated with a higher incidence of hypotension and requirement for dopamine and norepinephrine when compared to magnesium.

[Effect of magnesium sulphate and milrinone on cerebral vasospasm after aneurysmal subarachnoid hemorrhage: a randomized study]

BACKGROUND

Aneurysmal subarachnoid hemorrhage is an important cause of premature death and disability worldwide. Magnesium sulphate is shown to have a neuroprotective effect and it reverses cerebral vasospasm. Milrinone is also used in the treatment of cerebral vasospasm. The aim of the present study was to compare the effect of prophylactic magnesium sulphate and milrinone on the incidence of cerebral vasospasm after subarachnoid hemorrhage.

METHODS

The study included 90 patients with aneurysmal subarachnoid hemorrhage classified randomly (by simple randomization) into two groups: magnesium sulphate was given as an infusion of 500mg.day^-1 without loading dose for 21 days. Group B: milrinone was given as an infusion of 0.5μg.kg^-1.min^-1 without loading dose for 21 days. The cerebral vasospasm was diagnosed by mean cerebral blood flow velocity in the involved cerebral artery (mean flow velocity≥120cm.s^-1), neurological deterioration by Glasgow coma scale, or angiography (the decrease in diameter of the involved cerebral artery >25%).

RESULTS

The mean cerebral blood flow velocity decreased significantly in the magnesium group compared to milrinone group through Day 7, Day 14 and Day 21 (p<0.001). The incidence of cerebral vasospasm decreased significantly with magnesium compared to milrinone (p=0.007). The Glasgow coma scale significantly improved in the magnesium group compared to milrinone group through Day 7, Day 14 and Day 21 (p=0.036, p=0.012, p=0.016, respectively). The incidence of hypotension was higher with milrinone than magnesium (p=0.012).

CONCLUSIONS

The incidence of cerebral vasospasm after aneurysmal subarachnoid hemorrhage was significantly lower and Glasgow coma scale significantly better with magnesium when compared to milrinone. Milrinone was associated with a higher incidence of hypotension and requirement for dopamine and norepinephrine when compared to magnesium.

Effect of intrathecal milrinone injection via lumbar catheter on delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Delayed cerebral ischemia (DCI) is an important complication after aneurysmal subarachnoid hemorrhage (aSAH). Although intrathecal milrinone injection via lumbar catheter to prevent DCI has been previously reported to be safe and feasible, its effectiveness remains unknown. The goal of this study was to evaluate whether intrathecal milrinone injection treatment after aSAH significantly reduced the incidence of DCI.

METHODS

The prospectively maintained aSAH database was used to identify patients treated between January 2010 and December 2015. The cohort included 274 patients, with group assignment based on treatment with intrathecal milrinone injection or not. A propensity score model was generated for each patient group, incorporating relevant patient variables.

RESULTS

After propensity score matching, 99 patients treated with intrathecal milrinone injection and 99 without treatment were matched on the basis of similarities in their demographic and clinical characteristics. There were significantly fewer DCI events (4% vs 14%, p = 0.024) in patients treated with intrathecal milrinone injection compared with those treated without it. However, there were no significant differences between the 2 groups with respect to their 90-day functional outcomes (46% vs 36%, p = 0.31). The likelihood of chronic secondary hydrocephalus, meningitis, and congestive heart failure as complications of intrathecal milrinone injection therapy was also similar between the groups.

CONCLUSIONS

In propensity score–matched groups, the intrathecal administration of milrinone via lumbar catheter showed significant reduction of DCI following aSAH, without an associated increase in complications.

Sex-specific associations between cerebrovascular blood pressure autoregulation and cardiopulmonary injury in neonatal encephalopathy and therapeutic hypothermia

BACKGROUND

Cardiopulmonary injury is common in neonatal encephalopathy, but the link with cerebrovascular dysfunction is unknown. We hypothesized that alterations of cerebral autoregulation are associated with cardiopulmonary injury in neonates treated with therapeutic hypothermia (TH) for neonatal encephalopathy.

METHODS

The cerebral hemoglobin volume index (HVx) from near-infrared spectroscopy was used to identify the mean arterial blood pressure (MAP) with optimal autoregulatory vasoreactivity (MAPOPT). We measured associations between MAP relative to MAPOPT and indicators of cardiopulmonary injury (duration of mechanical respiratory support and administration of inhaled nitric oxide (iNO), milrinone, or steroids).

RESULTS

We identified associations between cerebrovascular autoregulation and cardiopulmonary injury that were often sex-specific. Greater MAP deviation above MAPOPT was associated with shorter duration of intubation in boys but longer ventilatory support in girls. Greater MAP deviation below MAPOPT related to longer intensive care stay in boys. Milrinone was associated with greater MAP deviation below MAPOPT in girls.

CONCLUSION

MAP deviation from MAPOPT may relate to cardiopulmonary injury after neonatal encephalopathy, and sex may modulate this relationship. Whereas MAP above MAPOPT may protect the brain and lungs in boys, it may be related to cardiopulmonary injury in girls. Future studies are needed to characterize the role of sex in these associations.

Basilar artery vasospasm after pretuncal non-aneurysmal subarachnoid hemorrhage responding to milrinone

Pretruncal (perimesencephalic) non-aneurysmal subarachnoid hemorrhage (PNSAH) is uniformly associated with an excellent outcome. Although cerebral vasospasm remains a common complication of SAH and constitutes an important predictor of outcome, in the setting of PNSAH, it is extremely rare. Preturnal non-aneurysmal subarac refers to a subset of SAH patients with a characteristic pattern of localized blood on CT of the head, normal cerebral angiography, and benign course when compared to the aneurysmal SAH population. The presence of radiological or even clinical vasospasm does not exclude the diagnosis of PNSAH. To our knowledge, this is the first case of symptomatic cerebral vasospasm due to PNSAH that responded to milrinone.

Anti-high mobility group box-1 (HMGB1) antibody attenuates delayed cerebral vasospasm and brain injury after subarachnoid hemorrhage in rats

Although delayed cerebral vasospasm (DCV) following subarachnoid hemorrhage (SAH) is closely related to the progression of brain damage, little is known about the molecular mechanism underlying its development. High mobility group box-1 (HMGB1) plays an important role as an initial inflammatory mediator in SAH. In this study, an SAH rat model was employed to evaluate the effects of anti-HMGB1 monoclonal antibody (mAb) on DCV after SAH. A vasoconstriction of the basilar artery (BA) associated with a reduction of nuclear HMGB1 and its translocation in vascular smooth muscle cells were observed in SAH rats, and anti-HMGB1 mAb administration significantly suppressed these effects. Up-regulations of inflammation-related molecules and vasoconstriction-mediating receptors in the BA of SAH rats were inhibited by anti-HMGB1 mAb treatment. Anti-HMGB1 mAb attenuated the enhanced vasocontractile response to thrombin of the isolated BA from SAH rats and prevented activation of cerebrocortical microglia. Moreover, locomotor activity and weight loss recovery were also enhanced by anti-HMGB1 mAb administration. The vasocontractile response of the BA under SAH may be induced by events that are downstream of responses to HMGB1-induced inflammation and inhibited by anti-HMGB1 mAb. Anti-HMGB1 mAb treatment may provide a novel therapeutic strategy for DCV and early brain injury after SAH.

Matrix metalloproteinase 9 may be involved in contraction of vascular smooth muscle cells in an in vitro rat model of subarachnoid hemorrhage

Our previous study determined that prominent cerebral vasospasm (CVS) may occur in an in vivo model of subarachnoid hemorrhage (SAH) in rats. Matrix metalloproteinase 9 (MMP‑9) expression levels in basilar arteries were upregulated in a similar manner to the development of CVS following SAH. To identify the changes that occur in the contractility of cerebrovascular smooth muscle cells and the expression levels of MMP‑9 in an in vitro model of SAH, rat cerebrovascular smooth muscle cells were isolated, cultured, and then stimulated with hemolysate. Additionally, 2-[(4-phenoxyphenylsulfonyl)methyl]thiirane (SB-3CT), a selective MMP-9 inhibitor, was used to determine the effect of MMP‑9 on the contractility of cerebrovascular smooth muscle cells. Cerebrovascular smooth muscle cells were successfully isolated and cultured in vitro, and hemolysate stimulation enhanced their contractility and increased MMP‑9 expression levels. The present study also revealed that pretreatment with SB‑3CT decreased MMP‑9 expression levels in cerebrovascular smooth muscle cells, and reduced their contractility upon hemolysate treatment. Therefore, the current study confirmed that MMP‑9 is important for the enhancement of the contractility of cerebrovascular smooth muscle cells in an in vitro rat model of SAH.

Cerebral Vasospasm: A Review

Cerebral vasospasm is a prolonged but reversible narrowing of cerebral arteries beginning days after subarachnoid hemorrhage. Progression to cerebral ischemia is tied mostly to vasospasm severity, and its pathogenesis lies in artery encasement by blood clot, although the complex interactions between hematoma and surrounding structures are not fully understood. The delayed onset of vasospasm provides a potential opportunity for its prevention. It is disappointing that recent randomized, controlled trials did not demonstrate that the endothelin antagonist clazosentan, the cholesterol-lowering agent simvastatin, and the vasodilator magnesium sulfate improve patient outcome. Minimizing ischemia by avoiding inadequate blood volume and pressure, administering the calcium antagonist nimodipine, and intervention with balloon angioplasty, when necessary, constitutes current best management. Over the past two decades, our ability to manage vasospasm has led to a significant decline in patient morbidity and mortality from vasospasm, yet it still remains an important determinant of outcome after aneurysm rupture.

Cerebral vasospasm

Cerebral vasospasm causes delayed ischemic neurologic deficits after aneurysmal subarachnoid hemorrhage. This is a well-established clinical entity with significant associated morbidity and mortality. The underlying patholphysiology is highly complex and poorly understood. Large-vessel vasospasm, autoregulatory dysfunction, inflammation, genetic predispositions, microcirculatory failure, and spreading cortical depolarization are aspects of delayed neurologic deterioration that have been described in the literature. This article presents a perspective on cerebral vasospasm, as guided by the literature to date, specifically examining the mechanism, diagnosis, and treatment of cerebral vasospasm.

Repeated combined endovascular therapy with milrinone and nimodipine for the treatment of severe vasospasm: preliminary results

BACKGROUND

Delayed vasospasm (VSP) following aneurysmal subarachnoid hemorrhage (aSAH) remains a major source of morbidity. Milrinone was recently suggested as an invasive VSP treatment option. It is a phosphodiesterase III inhibitor with vasodilating and additional positive inotrope and anti-inflammatory effects.

METHODS

In this preliminary series, we included patients with severe VSP and unsuccessful maximum conservative therapy. Inclusion criteria were (1) transcranial Doppler (TCD) mean >180 cm/s; (2) increase of >50 % of TCD mean values within 6 h to values >150 cm/s; and/or (3) neurological deterioration (after exclusion of hemorrhage, hydrocephalus, and other systemic reasons). Patients received endovascular therapy with nimodipine 2 mg followed by milrinone 4-8 mg. Reinterventions were indicated aggressively in cases of persistent neurological deficits or persistent high mean TCD >180 cm/s.

RESULTS

Of 121 consecutive aSAH patients, 16 (13.2 %) received endovascular VSP therapy. Of these, 11 patients (68.5 %) received ≥ 3 interventions (median 4; maximum 9); 14 (87.5 %) showed postinterventional angiographic improvement of vessel diameters; and 11 (68.5 %) showed improvement of their neurological deficits after a mean follow-up time of 4.5 months. No cardiovascular adverse events attributed to milrinone were observed.

CONCLUSIONS

Milrinone may be a useful supplementary substance for endovascular VSP therapy. Aggressive reintervention indications did not cause additional adverse events.

The use of intravenous Milrinone to treat cerebral vasospasm following traumatic subarachnoid hemorrhage

Introduction

Traumatic subarachnoid hemorrhage (SAH) is a common intracranial lesion after traumatic brain injury (TBI). As in aneurysmal SAH, cerebral vasospasm is a common cause of secondary brain injury and is associated with the thickness of traumatic SAH. Unfortunately, there is limited literature on an effective treatment of this entity. The vasodilatory and inotropic agent, Milrinone, has been shown to be effective in treating vasospasm following aneurysmal SAH. The authors hypothesized that this agent could be useful and safe in treating vasospasm following tSAH.

Case descriptions

Case reports of 2 TBI cases from a level 1 trauma centre with tSAH and whom developed delayed ischemic neurological deficits (DINDs) are presented. Intravenous Milrinone treatment was provided to each patient following the “Montreal Neurological Hospital Protocol”.

Discussion and evaluation

Both patients had an improvement in their DINDs following the treatment protocol. There were no complications of treatment and the Glasgow Outcome Scores of the patients ranged from 4 to 5.

Conclusion

This is the first report of the use of intravenous Milrinone to treat cerebral vasospasm following traumatic SAH. This treatment option appeared to be safe and potentially useful at treating post-traumatic vasospasm. Prospective studies are necessary to establish Milrinone’s clinical effectiveness in treating this type of cerebral vasospasm.

Milrinone and homeostasis to treat cerebral vasospasm associated with subarachnoid hemorrhage: the Montreal Neurological Hospital protocol

INTRODUCTION

For the treatment of cerebral vasospasm, current therapies have focused on increasing blood flow through blood pressure augmentation, hypervolemia, the use of intra-arterial vasodilators, and angioplasty of proximal cerebral vessels. Through a large case series, we present our experience of treating cerebral vasospasm with a protocol based on maintenance of homeostasis (correction of electrolyte and glucose disturbances, prevention and treatment of hyperthermia, replacement of fluid losses), and the use of intravenous milrinone to improve microcirculation (the Montreal Neurological Hospital protocol). Our objective is to describe the use milrinone in our practice and the neurological outcomes associated with this approach.

METHODS

Large case series based on the review of all patients diagnosed with delayed ischemic neurologic deficits after aneurysmal subarachnoid hemorrhage between April 1999 and April 2006.

RESULTS

88 patients were followed for a mean time of 44.6 months. An intravenous milrinone infusion was used for a mean of 9.8 days without any significant side effects. No medical complications associated with this protocol were observed. There were five deaths; of the surviving patients, 48.9 % were able to go back to their previous baseline and 75 % had a good functional outcome (modified Rankin scale ≤ 2).

CONCLUSION

A protocol using intravenous milrinone, and the maintenance of homeostasis is simple to use and requires less intensive monitoring and resources than the standard triple H therapy. Despite the obvious limitations of this study's design, we believe that it would be now appropriate to proceed with formal prospective studies of this protocol.

A novel intravital method to evaluate cerebral vasospasm in rat models of subarachnoid hemorrhage: a study with synchrotron radiation angiography

Precise in vivo evaluation of cerebral vasospasm caused by subarachnoid hemorrhage has remained a critical but unsolved issue in experimental small animal models. In this study, we used synchrotron radiation angiography to study the vasospasm of anterior circulation arteries in two subarachnoid hemorrhage models in rats. Synchrotron radiation angiography, laser Doppler flowmetry-cerebral blood flow measurement, [¹²⁵I]N-isopropyl-p-iodoamphetamine cerebral blood flow measurement and terminal examinations were applied to evaluate the changes of anterior circulation arteries in two subarachnoid hemorrhage models made by blood injection into cisterna magna and prechiasmatic cistern. Using synchrotron radiation angiography technique, we detected cerebral vasospasm in subarachnoid hemorrhage rats compared to the controls (p<0.05). We also identified two interesting findings: 1) both middle cerebral artery and anterior cerebral artery shrunk the most at day 3 after subarachnoid hemorrhage; 2) the diameter of anterior cerebral artery in the prechiasmatic cistern injection group was smaller than that in the cisterna magna injection group (p<0.05), but not for middle cerebral artery. We concluded that synchrotron radiation angiography provided a novel technique, which could directly evaluate cerebral vasospasm in small animal experimental subarachnoid hemorrhage models. The courses of vasospasm in these two injection models are similar; however, the model produced by prechiasmatic cistern injection is more suitable for study of anterior circulation vasospasm.

Milrinone, a phosphodiesterase III inhibitor, prevents reduction of jugular bulb saturation during rewarming from hypothermic cardiopulmonary bypass

Introduction: Inadequate cerebral oxygen balance during cardiopulmonary bypass may cause neuropsychological dysfunction. Milrinone, a phosphodiesterase III inhibitor, augments cerebral blood flow by direct vasodilatation. We conducted a prospective, randomized study in patients undergoing cardiac surgery with cardiopulmonary bypass to clarify the clinical efficacy of milrinone in the imbalance of cerebral oxygen supply and demand during the rewarming period of cardiopulmonary bypass.

Methods: This is a prospective, randomized and placebo-controlled study. After anesthesia, a 5.5 F fiberoptic oximeter catheter was inserted into the right jugular bulb retrogradely for monitoring the jugular venous oxyhemoglobin saturation (SjO2). Patients were randomly assigned to two groups, one receiving a continuous infusion of milrinone, 0.5 µg/kg/min during hypothermic cardiopulmonary bypass, and the other receiving saline as control.

Results: Milrinone significantly prevented the reduction of the jugular venous oxyhemoglobin saturation at 10 minutes from the start of rewarming compared with the control group, but did not do so from 10 to 20 minutes after rewarming.

Conclusion: Milrinone suppresses the reduction of SjO2 and improves the balance of cerebral oxygen supply and demand during the early rewarming period of hypothermic cardiopulmonary bypass.

Effect of intrathecal magnesium sulfate solution injection via a microcatheter in the cisterna magna on cerebral vasospasm in the canine subarachnoid haemorrhage model

OBJECTIVE

To evaluate intracisternal injection of magnesium sulfate (MgSO(4)) solution via a lumbar catheter for the treatment of cerebral vasospasm in the canine subarachnoid haemorrhage (SAH) model.

MATERIALS AND METHODS

SAH was induced in 7 beagle dogs using the dual haemorrhage model. Vertebral angiography was repeated on Day 1 (before SAH), and on Day 7 (during cerebral vasospasm) before and 1.5 hours after injection of 0.5 mL/kg of 15 mmol/L MgSO(4) in Ringer solution via the tip of a microcatheter placed in the cisterna magna from the lumbar spine.

RESULTS

After injection of MgSO(4) solution, the cerebrospinal fluid magnesium ion concentration significantly increased to 3.89 ± 0.97 mEq/L (P < 0.01) from the baseline value (1.49 ± 0.07 mEq/L). The arterial diameters of the basilar artery (BA), vertebral artery (VA), and superior cerebral artery (SCA) on Day 1 were 1.26 ± 0.19 mm, 1.10 ± 0.13 mm, and 0.74 ± 0.21 mm, respectively. On Day 7 before injection, the arterial diameters of the BA, VA, and SCA significantly decreased to 0.75 ± 0.27 mm, 0.74 ± 0.25 mm, and 0.36 ± 0.21 mm, respectively (P < 0.01), due to vasospasm, and were significantly increased to 0.91 ± 0.27 mm (P < 0.01), 0.91 ± 0.31 mm (P < 0.05), and 0.54 ± 0.14 mm (P < 0.01), respectively, after intracisternal injection of MgSO(4) solution.

CONCLUSIONS

Intracisternal MgSO(4) therapy using a microcatheter from the lumbar spine may be effective against vasospasm in the clinical setting of endovascular treatment of ruptured aneurysm.