Deep hypothermia and circulatory arrest for surgery of complex intracranial aneurysms

Efficacy and safety of adenosine, rapid ventricular pacing and hypothermia in cerebral aneurysms clipping: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

Cerebral aneurysms in complex anatomical locations and intraoperative rupture can be challenging. Many methods to reduce blood flow can facilitate its exclusion from the circulation. This study evaluated the safety and efficacy of using adenosine, rapid ventricular pacing, and hypothermia in cerebral aneurysm clipping.

METHODS

Databases (PubMed, Embase, and Web of Science) were systematically searched for studies documenting the use of adenosine, rapid ventricular pacing, and hypothermia in cerebral aneurysm clipping and were included in this single-arm meta-analysis. The primary outcome was 30-day mortality. Secondary outcomes included neurological outcomes by mRs and GOS, and cardiac outcomes. We evaluated the risk of bias using ROBIN-I, a tool developed by the Cochrane Collaboration. OpenMetaAnalyst version 2.0 was used for statistical analysis and I2 measured data heterogeneity. Heterogeneity was defined as an I2 > 50%.

RESULTS

Our systematic search yielded 10,100 results. After the removal of duplicates and exclusion by title and abstract, 64 studies were considered for full review, of which 29 were included. The overall risk of bias was moderate. The pooled proportions of the adenosine analysis for the different outcomes were: For the primary outcome: 11,9%; for perioperative arrhythmia: 0,19%; for postoperative arrhythmia: 0,56%; for myocardial infarction incidence: 0,01%; for follow-up good recovery (mRs 0-2): 88%; and for neurological deficit:14.1%. In the rapid ventricular pacing analysis, incidences were as follows: peri operative arrhythmia: 0,64%; postoperative arrhythmia: 0,3%; myocardial infarction: 0%. In the hypothermia analysis, the pooled proportion of 30-day mortality was 11,6%. The incidence of post-op neurological deficits was 35,4% and good recovery under neurological analysis by GOS was present in 69.2%.

CONCLUSION

The use of the three methods is safe and the related complications were very low. Further studies are necessary, especially with comparative analysis, for extended knowledge.

Adenosine-induced transient asystole to control intraoperative rupture of intracranial aneurysms: institutional experience and systematic review of the literature

BACKGROUND

Intraoperative rupture of an intracranial aneurysm is a life-threatening situation that carries a high risk of morbidity and mortality. Since 2000, adenosine has been used successfully to induce transient hypotension and/or asystole to control bleeding and facilitate surgical clipping of aneurysms that rupture intraoperatively. Given the paucity of reports describing this method in a limited number of patients, we performed a systematic review of the literature detailing the use and outcomes of this technique.

METHODS

The authors performed a systematic review and identified all studies in which adenosine was used in the setting of an intracranial aneurysm that ruptured intraoperatively. We then determined overall morbidity and mortality rates, adding an additional six of our own patients.

RESULTS

Data was analyzed for a total of 29 patients, including 23 previously reported patients from the literature and 6 additional cases from our own experience (mean age 54.8 years, 58.6% female). Most patients (82.8%, 24/29) presented with subarachnoid hemorrhage (SAH). Overall mean dose of adenosine was 51.8 mg. Successful clipping was achieved in 100% of patients. Transient or permanent morbidity was reported in 5/29 (17.2%) and the overall mortality rate was 31% (9/29), which occurred primarily due to an initial severe SAH and its resultant complications.

CONCLUSIONS

Adenosine-induced circulatory arrest appears to safely control intraoperative bleeding and facilitate the clipping of ruptured intracranial aneurysms based on the limited published literature available. Further studies comparing patient outcomes using this technique to traditional approaches are required to validate the safety and efficacy of adenosine in this high-risk setting.

Excellent Outcome 15 Years After Hypothermic Cardiac Standstill for Clipping of a Ruptured, Previously Coiled, Giant Basilar Tip Aneurysm

BACKGROUND

Giant, previously coiled basilar tip aneurysms are difficult to cure.

CASE DESCRIPTION

A 38-year-old woman with ruptured, giant, previously coiled basilar tip aneurysm was treated with clipping under hypothermic cardiac standstill and is doing excellently 15 years after surgery. Angiography did not show any recurrence.

CONCLUSIONS

Until endovascular treatment is proven on a long-term basis to cure similar aneurysms, surgery should remain an option.

Adenosine-induced transient asystole

Cerebral aneurysms are an important health issue in the United States, and the mortality rate following aneurysm rupture, or SAH, remains high. The treatment of these aneurysms uses endovascular options which include coil placement, stent assistant coiling and, recently, flow diversion. However, microsurgical clipping remains an option in those aneurysms not suited for endovascular therapy. These are often the more complicated aneurysms such as in large, giant aneurysms or deep-seated aneurysms. Circumferential visualization of the aneurysm, parent vessels, branches, perforators, and other neurovascular structures is important to prevent residual aneurysms or strokes from vessel or perforator occlusion. Decompression of the aneurysm sac is often required and we believe that adenosine-induced transient asystole should be an important option for clipping of complex cerebral aneurysms.

Extracorporeal membrane oxygenation for cardiac arrest during moyamoya cerebral revascularization surgery: case report

The authors describe the case of a 51-year-old man with bilateral moyamoya disease and prior strokes who developed an asystolic cardiac arrest while undergoing revascularization surgery under mild hypothermia. The patient was successfully treated with venoarterial (VA) extracorporeal membrane oxygenation (ECMO) after manual cardiopulmonary resuscitation (CPR) was unsuccessful for 45 minutes. ECMO is a cardiopulmonary support system that is indicated for respiratory failure in pediatric and adult patients. It is increasingly being used as an extension to mechanical CPR for patients who have suffered cardiac arrest if the underlying cause of cardiac arrest is thought to be reversible. Identifying which patients should be placed on emergency ECMO after cardiac arrest is controversial given its high morbidity and mortality. ECMO in neurosurgical settings has associated risks of intracranial hemorrhage and neurological compromise, while resource utilization is paramount given the high costs of this treatment. This paper is significant because it describes the use of ECMO in an unindicated setting. Limited data are available for ECMO usage after cardiac arrest with baseline cerebral ischemia. Furthermore, this paper raises important considerations for extracorporeal CPR use in a patient who had recently undergone craniotomy. The patient in this report remained on ECMO for 48 hours, after which he was successfully weaned. He developed a pericardial effusion and compartment syndrome from the ECMO but made a complete neurological recovery. Use of ECMO emergently in an appropriately chosen neurosurgical patient is safe, even in the setting of baseline cerebral ischemia and recent craniotomy.

Cardiac standstill for cerebral aneurysms in 103 patients: an update on the experience at the Barrow Neurological Institute. Clinical article

OBJECT

The aim of this study was to clarify the surgical indications, risks, and long-term clinical outcomes associated with the use of deep hypothermic circulatory arrest for the surgical treatment of intracranial aneurysms.

METHODS

The authors retrospectively reviewed 105 deep hypothermic circulatory arrest procedures performed in 103 patients (64 females and 39 males, with a mean age of 44.8 years) to treat 104 separate aneurysms. Patients' clinical histories, radiographs, and operative reports were evaluated. There were 97 posterior circulation aneurysms: at the basilar apex in 60 patients, midbasilar artery in 21, vertebrobasilar junction in 11, superior cerebellar artery in 4, and posterior cerebral artery in 1. Seven patients harbored anterior circulation aneurysms. Two additional patients harbored nonaneurysmal lesions.

RESULTS

Perioperatively, 14 patients (14%) died. Five patients (5%) were lost to late follow-up. At a mean long-term follow-up of 9.7 years, 65 patients (63%) had the same or a better status after surgical intervention, 10 (10%) were worse, and 9 (9%) had died. There were 19 cases (18%) of permanent or severe complications. The combined rate of permanent treatment-related morbidity and mortality was 32%. The mean late follow-up Glasgow Outcome Scale score was 4, and the annual hemorrhage rate after microsurgical clipping during cardiac standstill was 0.5%/year. Ninety-two percent of patients required no further treatment of their aneurysm at the long-term follow-up.

CONCLUSIONS

Cardiac standstill remains an important treatment option for a small subset of complex and giant posterior circulation aneurysms. Compared with the natural history of the disease, the risk associated with this procedure is acceptable.

Altered brain myelin sheath morphology after rewarming in situ

In this study cerebral ultrastructure was examined in an in vivo rat model, after rewarming from profound hypothermia (15-13 degrees C). Animals held at 37 degrees C served as controls. After rewarming, brains were examined by electron microscope. Micrographs were taken randomly, analyzed anonymously, and quantified by morphometry. Serum analysis of the stress marker S-100beta was carried out in identical groups. The most striking findings in rewarmed animals, when compared to controls, were alterations of myelin sheaths (p<.008) and elevated S-100beta (p<.0001). This indicates that cells in the central nervous system are susceptible to injury in an experimental model of accidental hypothermia and rewarming.

Circulatory arrest and deep hypothermia for the treatment of complex intracranial aneurysms--results from a single European center

BACKGROUND

Vascular neurosurgery faces the controversial discussion about the need for deep hypothermia and circulatory arrest (dh/ca) for the treatment of complex cerebral aneurysms. In this retrospective analysis, we present our experience in the treatment of 26 giant and large cerebral aneurysms under profound hypothermia and circulatory arrest.

METHODS

All patients were treated surgically under dh/ca. Seventeen patients had aneurysms of the anterior circulation, and nine patients had aneurysms of the posterior circulation. Thrombosis or calcification was found in ten patients. Eleven patients presented with subarachnoid hemorrhage. The seven patients with the longest circulation arrest time were analyzed in detail.

RESULTS

Subarachnoid hemorrhage led to hospital admission in 42% (n = 11) of cases. The overall mortality was 11.5%, and the overall morbidity was 15%. Ten patients deteriorated transiently but fully recovered. The mean age, Glasgow Coma Score, Fisher, and Hunt and Hess Score correlated significantly with the long-term outcome. Circulation arrest time correlated significantly to the neurological outcome on discharge. All patients with prolonged circulation arrest times had wide aneurysmal necks, and four had adjacent vessels to the dome or the parent vessel included in the neck. We observed a significant increase of neurological deficits immediately postoperatively, but this neurological deterioration resolved over time.

CONCLUSIONS

We observed neurological deterioration immediately postoperatively in 13 patients, but all patients fully recovered within 6 months except for four patients. A long cardiac arrest time reflected complex pathoanatomical conditions. We conclude that the clipping procedure under deep hypothermia and circulatory arrest remains a pivotal armament in complex vascular neurosurgery.

Deep hypothermic total circulatory arrest for internal carotid artery aneurysm extending into the cranium: experience from a developing country

Cardiopulmonary bypass is commonplace for acquired and congenital cardiac procedures. It has also stretched to facilitate complicated non-cardiac operations. Carotid artery aneurysms are treated both with surgical repair without cardiopulmonary bypass (CPB) and, occasionally, by utilizing CPB perfusion techniques. We have successfully repaired an internal carotid artery aneurysm, extending into cranium in a 30-year-old woman, by establishing deep hypothermic circulatory arrest on cardiopulmonary bypass.

Temporary balloon occlusion during the surgical treatment of giant paraclinoid and vertebrobasilar aneurysms

PURPOSE

We propose the combined neurosurgical-endovascular treatment with the balloon occlusion of parent artery during surgery of giant paraclinoid and vertebrobasilar aneurysms, which are unsuitable for a pure endovascular or surgical approach.

METHODS

Between January 2003 and December 2007, we treated surgically 15 giant aneurysms (11 paraclinoid and four vertebrobasilar) with the combined approach of surgery and endovascular intraoperative technique.

FINDINGS

Complete aneurysm occlusion was achieved in all 15 aneurysms, as confirmed by intraoperative angiographic control. In one paraclinoid aneurysm, a small recurrence became evident 1 year after surgery and needed coil embolisation.

CONCLUSIONS

The temporary balloon occlusion technique is useful and improves the safety of the unavoidable exposure of the parent artery in the surgical treatment of giant paraclinoid and vertebrobasilar aneurysms.

Intraoperative hypothermia during vascular neurosurgical procedures

Increasing evidence in animal models and clinical trials for stroke, hypoxic encephalopathy for children, and traumatic brain injury have shown that mild hypothermia may attenuate ischemic damage and improve neurological outcome. However, it is less clear if mild intraoperative hypothermia during vascular neurosurgical procedures results in improved outcomes for patients. This review examines the scientific evidence behind hypothermia as a treatment and discusses factors that may be important for the use of this adjuvant technique, including cooling temperature, duration of hypothermia, and rate of rewarming.

Accuracy of core temperature measurement in deep hypothermic circulatory arrest

Deep hypothermia is an effective technique for neuroprotection in cardiac surgery. However, standard body temperature measurement may deviate from actual brain temperature. Therefore, we simultaneously measured brain and core temperatures during neurosurgical interventions in hypothermic circulatory arrest to determine its accuracy. Between 1994 and May 2007, 26 patients (12 female, mean age 46+/-14 years), with complex intracranial aneurysms, underwent resection or clipping applying closed chest cardiopulmonary bypass and hypothermic circulatory arrest via inguinal cannulation. During surgery, temperature probes were positioned in the brain, tympanum, bladder, rectum and pulmonary artery. Mean cardiopulmonary bypass time was 147+/-39 min, mean circulatory arrest time was 28+/-8 min. Brain temperatures were best reflected by bladder and tympanum probes (Pearson's correlation coefficients: bladder=0.83; tympanum=0.80; pulmonary artery=0.63; rectum=0.37; P<0.05). Mean deviations from brain temperature were +0.2+/-2.7 degrees C at the tympanum, -0.8+/-2.6 degrees C in the bladder, -0.7+/-2.6 degrees C in the pulmonary artery and -1.8+/-4.4 degrees C in the rectum. In conclusion, temperature monitoring in the bladder and tympanum reliably reflects brain temperature. Temperature measurements in the pulmonary artery and rectum are less optimal.

Cardiopulmonary bypass as an adjunct for the noncardiac surgeon

The use of cardiopulmonary bypass (CPB) in noncardiac surgical settings has been increasingly developed and has greatly benefited noncardiac surgeon. A few years after the advent of CPB as well as profound hypothermic circulatory arrest in the early years, it was employed by neurosurgeons in cerebrovascular surgery and by general thoracic surgeons in carinal tumor resection. Indications for CPB were extended and modified year after year. It has facilitated not only the surgical management by surgeons of lesions that cannot be managed safely and effectively by conventional techniques, or conventional techniques carry significant risks to the patient, but also the preservation of the viability of multiple organ procurement, the practice of isolated limb perfusion for the treatment of malignancies of the extremities, and emergent cardiopulmonary resuscitation. Owing to the complications arising from CPB and profound hypothermic circulatory arrest, such as postoperative bleeding, coagulopathy, and neurologic deficits, efforts have been made to avoid these common hazards. Thus, innovative techniques including extracorporeal membrane oxygenation, percutaneous cardiopulmonary support, venovenous bypass, normothermic CPB, and minimally invasive approaches have emerged and played an important role as alternatives of standard CPB in decreasing morbidity and mortality and improving survival.

Non-cardiac surgery applications of extracorporeal circulation

Although the efficacy of extracorporeal circulation (ECC) is well established for open-heart surgery, application of ECC in other surgical areas has not been given much attention. Advances in the related surgical technique and anesthetic management combined with refinements in the ECC procedure itself have encouraged several institutions to use ECC for complex non-cardiac surgeries. ECC is beginning to be used for circulatory support or tissue oxygenation during surgery on the lung, brain, liver, and kidney as well as in emergency situations. With ECC, difficult and complex surgeries can be performed more safely, and the success rate of certain surgeries has been positively affected. It is important that the surgeon, anesthesiologist, and perfusionist are trained in non-cardiac surgery applications of ECC. Thus, we review here non-cardiac uses that have emerged and summarize the related procedures.

Deep Hypothermic Circulatory Arrest for Complex Cerebral Aneurysms: Lessons Learned

OBJECTIVE

Deep hypothermic circulatory arrest is a useful adjunct for treating complex aneurysms. Decreased cerebral metabolism and resultant ischemic tolerance create an environment suitable for devascularizing high-risk lesions. However, the advent of modern imaging modalities, innovative cerebral revascularization strategies, and the emergence of endovascular stenting and coiling limit the number of aneurysms requiring this surgical intervention. We present 66 patients with intracranial aneurysms who underwent surgical clipping under deep hypothermic arrest and attempt to identify patients well-suited for this procedure.

METHODS

This study was conducted during a 15-year period and examined patients with aneurysms of the anterior and posterior cerebral circulation. Demographics, aneurysm characteristics, and surgical factors were evaluated as predictors of functional outcome.

RESULTS

Patient age and the duration of cardiac arrest were independent predictors of early clinical outcome (P &lt; 0.05). Our experience suggests that the ideal patient is younger than 60 years old and harbors few medical comorbidities. Individuals with large aneurysms of the anterior communicating artery, internal carotid artery bifurcation, posterior inferior cerebellar artery, midbasilar, or vertebral arteries and with an absence of thrombosis and calcium may be most likely to experience favorable outcomes. Circulatory arrest should not exceed 30 minutes. Postoperative computed tomographic scanning and timely anesthetic emergence allow for early detection of hemorrhage. Complete dissection of the aneurysm before bypass and avoiding extreme hypothermia yield a low incidence of life-threatening postoperative hematomas.

CONCLUSION

Hypothermic circulatory arrest is a useful technique for neuroprotection during the clipping of complex cerebral aneurysms. This procedure, however, has several associated risks. Patient factors, pathoanatomic characteristics, and surgical parameters may be used to guide patient selection.

Giant Intracranial Aneurysms Treated With Deep Hypothermia and Circulatory Arrest

The use of deep hypothermic circulatory arrest (DHCA), using groin cannulation with the chest closed (CCDHCA), has improved the surgical treatment of large and giant cerebral aneurysms. Twelve consecutive ASA I-II patients (10 women and 2 men), with a mean age of 35 years (range 14 to 55 y) underwent DHCA for clipping or trapping of their aneurysm (giant, n=10; large, n=2; 42% posterior circulation), under balanced general anesthesia. Intraoperative standard monitors were completed with jugular oxygen saturation, pulmonary artery, pulmonary artery occlusion, central venous pressures, electroencephalography, evoked potentials, and cerebral (subdural), and core temperature. At the start of circulatory arrest, brain temperature was 15.1+/-1.1 degrees C (range 13.5 to 17.5), and core temperature 14.1+/-1.1 degrees C (range 12.7 to 17.0). Mean circulatory arrest time was 26.5+/-13.9 minutes (range 9 to 54) and anesthesia lasted 14+/-1 hours. Only one patient underwent DHCA with standard sternotomy, because of aortic insufficiency. Follow-up (up to 70 mo) revealed no deaths and Glasgow Outcome Scale at 6 months revealed good recovery in 9, moderate disability in 1, and severe disability in 2 patients. Selected patients with large/giant intracranial aneurysms, deemed unapproachable by conventional surgical techniques, were successfully treated using CCDHCA. Mortality rate was 0% and neurologic complications occurred in 25% of the patients.

The history and present status of deep hypothermia and circulatory arrest in cerebrovascular surgery

After the development of deep hypothermia and circulatory arrest for cardiothoracic procedures in the late 1950s, this technique was adopted by several neurosurgeons as an aid to complex cranial surgery. Woodhall and colleagues described its first use for a neurosurgical procedure in 1960. Although their case did not involve a cerebrovascular procedure, the technique was subsequently used for the surgical treatment of cerebrovascular lesions, especially complex and giant aneurysms as well as large and solid hemangioblastomas. At the beginning, incorporation of this technique into common neurosurgical practice was impeded by several factors. For example, postbypass coagulopathy had been a serious source of morbidity. Furthermore, the need for cooperation among multiple subspecialties and the requirements for expensive equipment had further limited the availability of this technique. Subsequent improvements in the technique and advances in the equipment designed for cardiopulmonary bypass have led to its more widespread use starting in the 1980s. Hypothermic circulatory arrest has been described in several reports as a safe and useful tool in the treatment of large and giant aneurysms. Nevertheless, improvements in endovascular procedures and further refinement in skull base surgical techniques have limited the indications for circulatory arrest and deep hypothermia. The authors describe the history of hypothermia and circulatory arrest, its implementation in cerebrovascular surgery, and the changes in indications for and results of its use over time.

Deep Hypothermia and Circulatory Arrest for Surgery of High Extracranial Internal Carotid Aneurysm

A large, high internal carotid artery aneurysm partially filled with thrombi in a young, 26-year-old male patient was treated by bypass grafting under deep hypothermia and circulatory arrest. This approach may be preferable to other alternatives in patients with high embolic risk and difficult exposure or inadequate space for distal carotid artery clamping.

Hypothermia with heparin-coated circuits and low dose systemic heparinization in neurosurgery

The purpose of this study was to evaluate the safety of profound hypothermic circulatory arrest with heparin-coated circuits and low dose systemic heparinization in the treatment of cerebral aneurysms. Surgery for giant intracranial aneurysms not operable using standard neurosurgical techniques was performed in 8 patients. All patients were placed on cardiopulmonary bypass using the closed-chest technique, except for the first patient who underwent open-chest bypass. Heparin was administered systemically (3,000 IU) and into the circuit (1,500 IU). Total circulatory arrest was begun at 20 degrees C. The D-dimer, alpha2 plasmin inhibitor-plasmin complex, thrombin-antithrombin III, and beta-thromboglobulin concentrations were measured to evaluate the changes in the coagulation and fibrinolytic systems during bypass. There were no neurologic or cardiac complications. None of the indicators of platelet activation, coagulation, or fibrinolysis were elevated. Hypothermic circulatory arrest combined with heparin-coated circuits and low dose systemic heparinization is safe for use in neurosurgery.

Failure of retrograde cerebral perfusion to attenuate metabolic changes associated with hypothermic circulatory arrest

OBJECTIVES

Although retrograde cerebral perfusion has become a popular adjunctive technique and may improve cerebral ischemic tolerance during hypothermic circulatory arrest, direct cerebral metabolic benefit has yet to be demonstrated in human subjects. We investigated the post-arrest metabolic phenomena with and without retrograde cerebral perfusion in patients.

METHODS

In a prospective randomized trial, 42 patients undergoing aortic surgery requiring hypothermic circulatory arrest were allocated to receive hypothermic circulatory arrest alone (n = 21) or hypothermic circulatory arrest with additional retrograde cerebral perfusion (n = 21). Circulatory arrest was commenced at 15 degrees C, and retrograde perfusion was instituted through the superior vena cava at a maximum jugular bulb pressure of 25 mm Hg. Transcranial, paired, repeated samples of the arterial and jugular bulb blood were analyzed for oxygen and glucose. Velocity in the right middle cerebral artery was also measured simultaneously.

RESULTS

There were 3 (7.1%) deaths and 3 (7.1%) episodes of neurologic deficit. Mean bypass and circulatory arrest duration (in minutes) were similar between groups (P =.4 and.14). The mean retrograde perfusion duration was 23 minutes. Post-arrest nasopharyngeal temperature was similar (15.3 degrees C vs. 15.3 degrees C). Retrograde perfusion did not affect post-arrest oxygen extraction, glucose extraction, or jugular bulb Po(2). There was no immediate lactate release immediately after hypothermic circulatory arrest.

CONCLUSIONS

Retrograde cerebral perfusion did not influence immediate post-arrest nasopharyngeal temperature or cerebral metabolic recovery. The low jugular bulb Po(2) suggests equivalent ischemia. These findings cast doubt on the effectiveness of retrograde cerebral perfusion as a metabolic adjunct to hypothermic circulatory arrest.

Aprotinin and deep hypothermic cardiopulmonary bypass with or without circulatory arrest for craniotomy

Deep hypothermic cardiopulmonary bypass with or without circulatory arrest has been used to facilitate the surgical repair of complex cerebrovascular lesions. The advantages of deep hypothermia have been tempered by the occurrence of coagulopathy that is associated with substantial morbidity and mortality. This study analyzed retrospectively the records of 13 patients who underwent cerebrovascular neurosurgery using deep hypothermic cardiopulmonary bypass with or without circulatory arrest during the period 1993 through 1999. All patients received the serine protease inhibitor aprotinin in an effort to avoid the development of a coagulopathy, defined as hemorrhage requiring reoperation. No patients developed postoperative intracranial hemorrhage. There was also no evidence of renal dysfunction, deep venous thrombosis, myocardial infarction, or pulmonary embolism. In conclusion, this study suggests that aprotinin may be beneficial to avoid the coagulopathy that is more likely to occur if deep hypothermic cardiopulmonary bypass with or without circulatory arrest is used for craniotomy without adverse effects on renal function or apparent thrombotic complications.

Anaesthetic considerations for patients undergoing hypothermic cardiopulmonary bypass for complex neurovascular lesions: case presentation and review

The anaesthetic management of a 38-year-old woman having excision of a meningioma involving the superior sagittal sinus is described. The procedure was performed using low flow moderate hypothermic cardiopulmonary bypass with central cannulation. Relevant literature is reviewed.

New application of heparin-bonded extracorporeal membrane oxygenation in difficult neurosurgery

We wished to evaluate the safety and the advantages of using heparin-bonded extracorporeal membrane oxygenation (ECMO) to replace conventional cardiopulmonary bypass (CPB) in deep hypothermic circulation for complex cerebral aneurysm surgery.Heparin-bonded ECMO without the bridging tube and the cardiotomy reservoir was set up through the femoral vessels. Limited heparin was infused. In deep hypothermia, the ECMO blood flow was temporarily decreased as low as the neurosurgeons' request. It was applied to 4 patients with difficult intracranial aneurysms who were selected for the procedure. Clipping, wrapping, or vascular bypass was implemented to manage the aneurysms under deep hypothermia. The total heparin dosage used in the whole procedure was 9,875 +/- 1,625 U, and the mean ECMO time was 270 +/- 105 min. The blood consumption was packed red blood cell 3.0 +/- 0.5 U and fresh frozen plasma 3.8 +/- 2.3 U. Compared with our previous experiences using conventional CPB, ECMO did need less heparin and blood transfusions. Clipping was applied in 2 patients, wrapping in 1, and venous graft interposition was performed in 1. Mortality occurred in 1 patient (25%) due to brain herniation. This preliminary study suggested that the heparin-bonded ECMO without reservoir in deep hypothermia could be safe in cerebral aneurysm surgery under a low flow circuit.

Closed chest hypothermic circulatory arrest for complex intracranial aneurysms

BACKGROUND

Recent advances in techniques of cardiopulmonary bypass permitted hypothermic circulatory arrest (HCA) using groin cannulation with the chest closed (CC-HCA) and without direct access to the heart. Herein we describe our experience with this technique for complex intracranial aneurysms.

METHODS

Between 1992 and 1999, 16 patients (4 men and 12 women) with a mean age of 52 years (range 32 to 61 years) with complex intracranial aneurysms underwent resection or clipping of their aneurysms at our institution using the technique of CC-HCA and groin cannulation. Groin access was obtained with 16F to 19F arterial and 18F to 20F venous cannulas placing the tips at the aortoiliac and atriocaval junctions, respectively. Patients were cooled to a nasopharyngeal temperature of 16 degrees C.

RESULTS

Mean circulatory arrest time was 32 minutes. No patient required conversion to standard sternotomy and central cannulation. There were no intraoperative deaths. The 30-day hospital mortality was 2 of 16 patients (12%). Of the 14 surviving patients (88%), 1 developed bilateral third nerve palsy and another left hemiparesis that improved on follow-up. Both were discharged to an extended care facility and continued to do well at home after discharge. Two patients developed deep venous thrombosis postoperatively and required anticoagulation. All patients continued to do well at a mean follow-up of 42 months.

CONCLUSIONS

The less invasive technique of CC-HCA through groin cannulation avoids complications associated with a sternotomy, is safe and is associated with little morbidity, reduced operative time, and early hospital discharge and rehabilitation.

Centrifugal pumps and heparin-coated circuits in surgical treatment of giant cerebral aneurysms

Giant cerebral aneurysms may be untreatable by conventional neurosurgical techniques. Early attempts to use circulatory assistance and deep hypothermia were abandoned due to hemorrhagic complications. More recently, interest in circulatory support for complex neurosurgical procedures has been renewed. A consecutive series of 8 patients were operated on for giant cerebral aneurysms with the combined use of deep hypothermia. The protocol included careful preoperative cardiovascular assessment, perfect intraoperative synergy between neurosurgical and cardiac teams, minimally invasive peripheral vascular access including two femoral vein (21 F) and single arterial (17 F) femoral cannulation, use of total Carmeda coating on BioMedicus pumps in closed circuits, and reduced heparinization without Protamine reversal. All cerebral aneurysms were successfully treated through deep hypothermia (15-18 degrees C) as assessed by intraoperative fluoroscopic controls and Doppler vascular assessment. Mean circulatory support time was 174.2 +/- 29.6 min. Circulatory arrest period was 20 +/- 12 min. All patients survived and were extubated within 48 h. No major deficit was observed clinically or on postoperative CT scan. No hemorrhagic complications occurred (mean transfusions was 2.2 blood units). This work supports an extensive use of heparin-coated surfaces for complex circulatory assist techniques, either for cardiac or extra cardiac complex procedures.