Vasospasm after SAH due to aneurysm rupture of the anterior circle of Willis: value of TCD monitoring

OBJECTIVE: The aim of this study was to verify the presence of angiographic vasospasm in patients with transcranial Doppler (TCD) of high velocities after subarachnoid hemorrhage (SAH). METHODS: Seven hundred and eighty-six cases admitted within 48 hours after SAH due to the rupture of anterior circulation aneurysm, were prospectively studied with TCD. In cases of TCD velocities higher than 120 cm/s (TCD vasospasm), the patient underwent a control angiography. Hunt-Hess and Fisher's grade on admission CT and location of the aneurysm were related to occurrence of TCD vasospasm. The increase in TCD velocities within 24 hours was calculated and related to the presence of cerebral ischemia on discharge CT, considering three groups of patients: Group A with an increase in velocities higher than 60%, Group B with an increase in velocities between 30 and 60%, and Group C with an increase in velocities lower than 30%. RESULTS: TCD vasospasm was observed in 216 patients (27%). In 97% of patients with TCD vasospasm on middle cerebral artery (MCA) and in 71% with TCD vasospasm on anterior cerebral artery (ACA), control angiography confirmed the vasospasm, with a significant lower diagnostic TCD predictivity of ACA spasm (chi2=28.204, p=0.000). The overall positive predictive value of TCD was 89%. There was no significant correlation of TCD vasospasm with clinical status on admission and location of the aneurysm, but a significant correlation between occurrence of TCD vasospasm and Fisher's grade (chi2=15.470, p=0.002) and between the increase rate in TCD velocities and cerebral ischemia (chi2=56.564, p=0.000). CONCLUSION: Our study shows a good correlation between TCD and angiography to detect vasospasm on MCA, but the correlation is low for ACA. TCD alone cannot discriminate different hemodynamic pathways after SAH.     

Cerebral energy failure after subarachnoid hemorrhage: the role of relative hyperglycolysis.

After subarachnoid hemorrhage (SAH) cerebral metabolism is significantly impaired. Hyperglycolysis describes the reduction of oxidative metabolism followed by a relative increase of anaerobic glycolysis to maintain energy supply. This phenomenon is known in head injury but has not as yet been shown after SAH. This study was conducted to test the hypothesis that hyperglycolysis is present in SAH patients and is associated with vasospasm. A total of 105 measurements were conducted on 21 SAH patients (age 49+/-15 years, median World Federation of Neurosurgical Societies Grade 4) over the first 5 days following admission. Arteriovenous differences were calculated for oxygen (avDO2) and glucose (avDGlc). Relative hyperglycolysis was defined as metabolic ratio (MR=avDO2[mmol/L]/avDGlc[mmol/L])<3.44. Jugular-venous saturation for oxygen (SjvO2), mean arterial blood pressure (MAP), intracranial pressure (ICP), cerebral perfusion pressure (CPP) were monitored. Relative hyperglycolyis was recorded in 34% of studies after SAH. In hyperglycolytic studies both jugular-venous lactate and SjvO2 were significantly elevated (jugular-venous lactate 14.9+/-9.9 vs. 11.8+/-5.5 mg/dL, p=0.04; SjvO2: 70.0+/-18% vs. 81.7+/-9%, p=0.002). Relative hyperglycolysis is associated with outcome after SAH. In patients who died after SAH almost 50% of studies showed hyperglycolysis, whereas patients who survived without neurological deficit had no hyperglycolytic events. Relative hyperglycolysis is a common event after SAH. It may be associated with relative hyperemia but most importantly with outcome.     

Transdermal nitroglycerin in patients with subarachnoid hemorrhage

Delayed ischemic neurological deficit (DIND) following cerebral vasospasm remains a cause for high morbidity and mortality in patients with subarachnoid hemorrhage (SAH). There is experimental and clinical evidence of positive effects of nitric oxide (NO) donors on cerebral vasospasm. We therefore analysed the effect of transdermal nitroglycerin in patients with SAH measuring transcranial Doppler velocities (TCD), cerebral blood flow (CBF) and DIND. Nitroglycerin was used in a target dose of 14 microg/kg/h. TCD assessment was performed daily. CBF measurements were done using the perfusion CT-technique. Blood pressure, volume intake and vasopressor administration, were registered. Nine patients were randomly assigned either to the nitroglycerin group (N-group) and eight patients in the control group (C-group). Mean TCD values in the extracranial portion of the internal carotid artery (ICA) were lower in the N-group (p<0.005). Mean TCD in the middle cerebral arteries (MCA) showed no difference. The Lindegaard ratio was higher in the N-group (p<0.04). CBF in the N-group was higher than in the C-group (p<0.03). Even though nitroglycerin reduces blood pressure and lowers ICA TCD-values and increases the Lindegaard ratio, a higher CBF was measured in the N-group. Thus, nitroglycerin influences the cerebral vascular tone and increases CBF. SAH therapy with nitroglycerin is possible without increasing the risk of DIND. The exact timing of onset, duration and reduction of nitroglycerin administration in respect to the appearance of vasospasm may have a strong impact on the success of such a therapy.     

蛛网膜下腔出血后脑血管痉挛与血管活性物质的关系

目的 探讨蛛网膜下腔出血后脑血管痉挛与血管活性物质的关系。方法 测定52例蛛网膜下腔出血患者血浆血栓素B_2(thromboxane B_2,TXB_2)、6-酮-前列环素F1α(6-keto-prostaglandin,6-Keto)及血浆和脑脊液中血管紧张素转化酶(angiotensin converting enzyme,ACE)活性,同时通过经颅多普勒超声检查法(transcranial Doppler nltrasonography,TCD)观察蛛网膜下腔出血后脑血管平均血流速度(Vm)的变化,并与正常对照组进行比较。结果 蛛网膜下腔出血患者血浆TXB_2水平高于对照组(P<0.01),6-Keto水平低于对照组(P<0.05或P<0.01);发病后血浆ACE活性无明显改变,但脑脊液中ACE活性高于对照组(P<0.01);大脑中动脉平均血流速度于蛛网膜下腔出血后第4～5d的变化最为显著(P<0.01)。结论 蛛网膜下腔出血后患者血浆TXB_2、6-Keto与脑脊液ACE水平均发生明显变化,结合TCD检测结果,推测蛛网膜下腔出血后脑血管痉挛与血管活性物质水平有关。     

Doppler ultrasound measurement of blood flow volume in the extracranial internal carotid artery for evaluation of brain perfusion after aneurysmal subarachnoid hemorrhage

Monitoring of cerebral blood flow (CBF) is an essential part in the early diagnosis of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH). Several methods have been established to monitor cerebral perfusion in these patients. During last few years, a new sonographic approach has been introduced, the so called 'angle independent ultrasound system' for monitoring volume flow in the internal carotid artery (ICA). The angle independent Doppler ultrasound system Quantix ND (Cardiosonix Ltd, Israel) determines the diameter of the ICA as well as the velocity of blood flow in the extracranial part of this vessel. Thus, a determination of the global CBF in the anterior circulation can be achieved. Aim of our study was to compare the Quantix ND system and the commonly used transcranial Doppler sonography (TCD) in patients suffering from aneurysmal SAH. We included 11 patients (eight female and three male; Hunt and Hess I-V) and performed post-operatively/post-interventionally daily measurement of blood flow volume in the ICA, and determined the blood flow velocity in middle and anterior cerebral artery (MCA and ACA) with TCD. Six patients post-operatively/post-interventionally developed cerebral vasospasm, resulting in ischemia and territorial infarction. Three patients were chosen as case studies. In contrast to the TCD, we found a strong significant correlation of blood flow volume with Quantix ND in the ICA and the occurrence of cerebral infarction (p<0.001). These preliminary data justify further investigation of this angle independent Doppler ultrasound device. We postulate that this new tool might be effective for monitoring the CBF in the critical post-operative/post-interventional interval following aneurysmal SAH.     

The importance of traumatic subarachnoid haemorrhage

Post-traumatic cerebral vasospasm is being increasingly recognised as a possibly significant complication after head injury. To assess the relationship between post-traumatic subarachnoid haemorrhage (tSAH) and post-traumatic vasospasm, 63 patients with severe head injury (GCS 3-8) were studied. Forty-seven patients had cerebral contusion on the initial CT scan. In 25 of these (Group I) there were only contusions, while 22 (Group II) also had tSAH. All patients had daily measurements of blood flow velocity in the basal cerebral arteries using transcranial Doppler ultrasound (TCD). The incidence of vasospasm detected by TCD was significantly higher in Group II. Furthermore there were significantly fewer good outcomes (GOS 1 and 2) in this group. These results suggest that the presence of subarachnoid blood in patients with severe head injury is associated with a risk of vasospasm, and with poorer outcome.     

经颅多普勒监测蛛网膜下腔出血后脑血管痉挛的临床观察

目的总结应用经颅多普勒(TCD)监测蛛网膜下腔出血(SAH)后脑血管痉挛的临床价值。方法对2015-06—2016-05本院收治的78例SAH患者进行回顾性分析,均进行TCD监测,同时对患者进行数字减影血管造影(DSA)检查,观察各个时间段患者颅内血管血流速度变化,并以DSA检查结果作为标准判断TCD诊断颅内血管痉挛的价值。结果在7~10d时间段,患者的MCA、ACA、VA、BA血流速度达到峰值,后逐渐下降,颅内血管痉挛现象逐渐缓解;SAH患者MCA、ACA、VA、BA血流速度在7d、7~10d、10~14d三个时间段比较差异均具有统计学意义(P0.05);78例SAH患者,TCD诊断发生颅内血管痉挛59例,DSA诊断发生率颅内血管痉挛62例,TCD诊断SAH患者发生颅内血管痉挛的灵敏度为93.55%、特异度为93.75%、漏诊率为6.45%、误诊率为6.25%,TCD诊断颅内血管痉挛与DSA的一致性Kappa=0.816,P0.05。结论 TCD检查诊断SAH后出现颅内血管痉挛具有准确性高、无创等优点,值得临床推广应用。     

蛛网膜下腔出血后脑血管痉挛实验研究

目的　在兔蛛网膜下腔出血 (SAH)模型上 ,尝试建立经颅多普勒超声 (TCD)及血管造影 ,监测椎基动脉脑血管痉挛 (CVS)的新方法。方法　兔枕大池一次性注血 ,同时行逆行颈总动脉插管椎基动脉造影及开骨窗TCD监测。结果　逆行性脑血管造影能清晰显示椎基底动脉系统 ,注血前后血管直径差异明显 (P <0 .0 5 ) ,平均血流速度注血后明显增快 ,但中、重度痉挛之间基底动脉血流速度变化无明显差异。结论　一侧颈总动脉逆行插管椎基动脉造影 ,操作简便 ,结果可靠。采取开骨窗以提高TCD超声频率的方法 ,可获得兔基底动脉稳定的频谱图并易于重复。     

Vasospasm followed by diastolic flow reversal in the intracranial arteries after subarachnoid haemorrhage.

Vasospasm and raised intracranial pressure (ICP) are common complications in subarachnoid haemorrhage (SAH) due to ruptured intracranial aneurysm. Vasospasm can be reliably monitored by repeated transcranial Doppler (TCD) examinations. The changes in flow velocities due to vasospasm are useful for early diagnosis, monitoring effectiveness of treatment and determining prognosis. Intracranial pressure can also increase to dangerous levels and affect blood flow in the intracranial circulation. These changes in ICP may be evaluated by the spectral waveform patterns obtained during TCD examination. We describe the dynamic TCD spectral changes in a patient with SAH that progressed from vasospasm to diastolic flow reversal. These temporal changes observed during serial TCD examinations were well correlated with the ICP. Transcranial Doppler is a reliable, beat-to-beat, non-invasive and reproducible bedside test that can be used to monitor vasospasm and ICP in SAH. The use of TCD can be extended to other intracranial diseases that can potentially lead to an abnormally high ICP.     

Blood flow velocities in middle cerebral artery branches after subarachnoid hemorrhage.

In a prospective study, 55 patients were examined by transcranial duplex sonography (TCCS) after subarachnoid hemorrhage (SAH) to determine whether additional transcranial duplex examination on the middle cerebral artery M2 segments would aid in the examination of the MCA stem segment. The mean blood flow velocities and pulsatility index were correlated to the occurrence of delayed ischemic neurologic deficits (DIND). Out of 47 patients included, 21 did not experience any delayed deficit (group I), 15 did (group II), and in 11 the extent to which vasospasm contributed to a neurologic deficit was unclear (group III). The highest blood flow velocity and the greatest increase of mean blood flow velocity on 1 day were significantly higher in groups II and III both in M1 and in M2. In 10 patients in group II, where the onset day of DIND was known exactly, Doppler data indicating ischemia before or at the time of DIND were observed in nine. In eight patients, Doppler of the MCA stem alone would have provided enough information to recognize the risk of symptomatic vasospasm; in one patient, only the M2 Doppler gave an indication of ischemic complication. Transcranial duplex sonography may provide additional information to TCD by accurate delineation of M1/M2 vasospasm and therefore may help plan cerebral angiography and neurointerventional treatment.     

Sensitivity and specificity of transcranial Doppler ultrasonography in the diagnosis of vasospasm following subarachnoid hemorrhage

Vasospasm is the leading cause of death and disability in patients with aneurysmal subarachnoid hemorrhage (SAH). Transcranial Doppler ultrasonography (TCD) can detect the arterial narrowing noninvasively, but the sensitivity and specificity of this technique have not been reported in a population of patients with a high frequency of angiographic vasospasm. In this study, 34 consecutive patients with SAH undergoing angiography during the period of risk for vasospasm had technically adequate TCD examinations within 24 hours of the angiogram. Using a mean flow velocity of 120 cm/sec and above as indicative of vasospasm, TCD correctly detected angiographic vasospasm in 17 patients; there were no false positives. It correctly determined that 5 patients did not have vasospasm, whereas there were 12 false negatives. False negatives were frequently due to angiographic vasospasm involving vessels not assessable by TCD. The correlation between mean flow velocity and the angiographic residual lumen diameter of the middle cerebral artery was statistically significant. These data suggest that TCD is a highly specific (100%), but less sensitive (58.6%) test for the detection of angiographic vasospasm following SAH. Confirmatory angiography may be avoided if the TCD study is positive, but additional studies may be necessary if the clinical picture is suspicious and the TCD study is negative.     

Transcranial Doppler ultrasonography in the neurologic intensive care unit

Transcranial doppler ultrasonography (TCD) is a noninvasive monitoring tool which allows imaging of blood flow velocities in intracranial blood vessels. It is safe, portable, easy to perform and provides accurate information regarding underlying physiology which may help to guide therapy in critically ill neurologic patients. It has significantly contributed to the management of vasospasm related to subarachnoid hemorrhage in the neurologic intensive care unit. TCD is also helpful in the early diagnosis of a variety of complications that can occur in patients with head injury such as vasospasm, elevated intracranial pressure and disordered cerebral autoregulation. Careful performance of the test and experienced interpretation can identify TCD waveforms indicative of cerebral circulatory arrest, an ancillary finding used for the diagnosis of brain death. TCD is likely to play a larger role in evaluation of the patient in the future because of its safety, portability and ability to define moment-to-moment changes in cerebral blood flow velocities and cerebral blood flow.     

Relative changes in flow velocities in vasospasm after subarachnoid hemorrhage

Introduction: Transcranial Dopplers (TCDs) have been used to monitor cerebral blood flow velocities in subarachnoid hemorrhage (SAH). The purpose of our two-part study was to compare the reliability of relative increases in flow velocities with conventionally used absolute flow velocity indices and to correct for hyperemia-induced flow velocity change. Methods: Part 1: Charts of 50 patients admitted to Hahnemann University Hospital with aneurismal SAH were reviewed. Mean middle cerebral artery maximum flow velocities (MCA-MFV) were reviewed for initial flow velocities (IFVs) and maximal flow velocities (MFVs) that were reached during hospital course. Correlating flow velocities (SFVs) were noted in patients who developed symptomatic vasospasm. MFV/IFV and SFV/IFV ratios were calculated to evaluate relative changes in flow velocity. Part 2: Correction for hyperemia was derived from Lindegaards Ratio using extracranial internal carotid artery (ICA) flow velocity ratio (corrected MCA-MFV/observed MCA-MFV=EC-ICAFV (day1)/observed EC-ICAFV). Results: Part 1: All 10 patients who developed symptomatic vasospasm exhibited a twofold increase (SFV/IFV: >2) in flow velocities prior to developing symptomatic vasospasm, and 5 patients had a threefold increase (SFV/IFV: >3). Of the 40 patients who did not develop symptomatic vasospasm, 33 patients did not have a twofold increase in their flow velocities at any time. The positive predictive value for MFV/IFV greater than 3 (n=6) and SFV/IFV greater than 3 (n=5) was 100%. The negative predictive value for MFV/IFV less than 2 (n=33) was 100%. Data using relative changes (twofold increase) in flow velocity was more sensitive (100 to 90%), specific (83 to 70%), and predictive (positive predictive value [PPV]: 59 to 45%; negative predictive value [NPV]: 100 to 97%) for symptomatic vasospasm than absolute flow velocity indices using MCA-MFV greater than 120—even in combination with Lindegaards Ratio (MCA/ICA greater than 3). Part 2: Correction for hyperemia by modifying Lindegaard’s Index in the 32 patients where data was available improved the PPV of absolute flow velocities from 44 to 62%. In this population, the application of this equation while evaluating relative change in flow velocities improved PPV of twofold increase from 57 to 73%. Conclusion: Relative changes in flow velocities in patients with aneurysmal SAH correlated better with clinically significant vasospasm than absolute flow velocity indices. Correction for hyperemia improved predictive value of TCD in vasospasm.     

Monitoring with the Somanetics INVOS 5100C After Aneurysmal Subarachnoid Hemorrhage

Introduction  Vasospasm is a major cause of morbidity after subarachnoid hemorrhage (SAH), and current screening techniques (angiography, transcranial Doppler [TCD], and clinical examination) have serious limitations. Brain oximetry is a promising noninvasive tool to detect reduced brain oxygenation from vasospasm. Methods  Consecutive SAH patients at high risk for vasospasm were monitored with the INVOS (Somanetics, IL, USA) 5100C cerebral oximeter. We prospectively collected oximeter readings (rO2) with concurrent values for vital signs, intracerebral pressure (ICP), arterial blood gas measurement, and hemoglobin (HGB). Data were prospectively collected every 12 h and at clinical events (angiography, transfusion, etc.). We prospectively recorded clinical history, clinical events, radiology results, and outcomes. Results  Six patients were measured 123 times. rO2 values were correlated with the contralateral side, HGB, blood pressure, and PaO2, but not with ICP or perfusion pressure. There were no measured effects of angiography or transfusion. Patterns relating rO2 readings to clinical, angiographic, or TCD evidence of vasospasm were unclear, and there were no associations with the outcome (cerebral infarction, NIH Stroke Scale, or modified Rankin Scale). Conclusion  INVOS rO2 readings are associated with other factors that relate to cerebral oxygen delivery but seem to be of limited use as a screening tool for vasospasm or cerebral infarction after SAH.     

Is Transcranial Doppler Ultrasonography Old-fashioned?: One Institutional Validity Study

Objective

The purpose of this study is to investigate the correlation between various transcranial Doppler (TCD) ultrasonography parameters and clinical vasospasm after aneurysmal subarachnoid hemorrhage (SAH).

Methods

This study enrolled 40 patients presented with aneurysmal SAH between September 2006 and August 2007. We measured differences of mean blood flow velocity (BFVm), highest systolic blood flow velocity (BFVh), and Lindegaard ratio (LR) in the middle cerebral artery on TCD examination. These parameters were evaluated for correlation with clinical vasospasm by univariate analysis and the receiver operating characteristic analysis.

Results

Twelve patients (30%) developed clinical vasospasm. The best TCD parameters for the detection of clinical vasospasm were revealed to be differences of BFVm, BFVh, and LR values between 1^st TCD test and 3^rd TCD (7 cm/s, 11.5 cm/s, 0.45 respectively). The positive predictive value of any one of three parameters was 60% and the negative predictive value was 100%.

Conclusion

TCD is still considered a useful tool for screening clinical vasospasm. To confirm the predictive value of the above parameters, further prospective study will be needed.     

兔蛛网膜下腔出血后脑血管痉挛与脑细胞外液相关性实验研究

目的探讨蛛网膜下腔出血(SAH)后脑血管痉挛的脑代谢变化规律及其与脑血管痉挛程度的相关性。方法 16只成年新西兰白兔随机分为:枕大池2次注生理盐水组(NS组)8只,枕大池2次注血组(SAH组)8只。两组均采用微透析仪于注血(或生理盐水)前、后第1,3,5,7天检测脑细胞外液的葡萄糖、乳酸、丙酮酸、谷氨酸及天冬氨酸的浓度,并计算乳酸与丙酮酸(L/P)比值。经颅多普(TCD)测定两组兔基底动脉血流速度;DSA测定两组兔基底动脉直径。结果与注血前相比,SAH组注血后各指标均有不同程度变化。基底动脉直径显著缩小及血流速度明显增快均于第3天开始(P0.05),并于第5天达高峰;且轻度和中度脑血管痉挛血流速度与管径呈负相关(γ轻=0.673,P0.01;γ中=0.613,P0.01)。乳酸和L/P比值均于第1天明显升高(P0.05),第5天达高峰;且与基底动脉直径变化呈负相关(γ乳酸=0.624,P0.01;γL/P=0.713,P0.01)。谷氨酸第1天显著升高(P0.05),后急剧下降。结论 TCD可通过检测血流速度变化判断兔脑血管痉挛情况,但痉挛程度的判断存在局限性。脑细胞外液乳酸和L/P比值变化可预测兔脑血管痉挛的发生并判断其痉挛程度。     

Lower Head of the Bed Position Does Not Change Blood Flow Velocity in Subarachnoid Hemorrhage

Background  

Transcranial Doppler (TCD) is commonly used to monitor for vasospasm in patients with aneurysmal subarachnoid hemorrhage (aSAH). Changes in head of the bed (HOB) positions alter blood flow velocities measured by TCD in patients with ischemic stroke. However, the effects of HOB position on the velocities of the cerebral blood flow have not been studied in aSAH patients.     

Bedside-microdialysis for early detection of vasospasm after subarachnoid hemorrhage. Case report and review of the literature

Continuous monitoring of cerebral metabolism would be desirable for early detection of vasospasm in SAH patients. Bedside-microdialysis, a new technique for on-line monitoring of cerebral metabolism, may reflect changes seen in cerebral vasospasm diagnosed by transcranial Doppler sonography (TCD). This report represents the first case of combined TCD monitoring and on-line microdialysis from the brain extracellular fluid in a SAH patient. A 48-year-old woman suffered subarachnoid hemorrhage grade IV according to Hunt and Hess. Angiography revealed an aneurysm of the left carotid artery. The aneurysm was clipped 45 hours after bleeding. The microdialysis catheter was inserted after aneurysm clipping into the white matter of the left temporal lobe. Sampling of microdialysates started immediately, analyzing time for glucose, lactate, pyruvate and glutamate was four minutes. Postoperatively, the patient was doing well and microdialysis and TCD parameters remained within normal range. On the third postoperative day a shift to anaerob metabolism (decrease of glucose, increase of lactate and the lactate-pyruvate ratio up to pathological levels) and an increase in glutamate was observed suggesting insufficient cerebral perfusion. The patient progressively deteriorated clinically. Vasospasm was diagnosed by TCD monitoring 36 hours after onset of ischemic changes monitored by microdialysis. After elevation of mean arterial blood pressure, TCD values and metabolic parameters normalized. Interestingly, the pathological changes in on-line microdialysis preceded the typical increase in blood flow velocity by TCD and the clinical deterioration. Our case suggests, that bedside-microdialysis may be useful for early detection of vasospasm and continuous surveillance of treatment and may be a new guide to treat ischemic neurological deficits following SAH.     

Progress in NIRS monitoring of cerebral blood flow

Various studies have demonstrated the usefulness of near infrared spectroscopy (NIRS) for detecting cerebral ischemia during a carotid endarterectomy; however, it is difficult to apply NIRS to the diagnosis of ischemic stroke, since commercially available NIRS, which uses continuous-wave light, does not provide quantitative values of baseline hemoglobin (Hb) concentrations. In contrast, time-resolved near-infrared spectroscopy (TRS) permits quantitative measurement of Hb concentrations. We applied TRS to detection of cerebra vasospasm after subarachnoid hemorrhage (SAH). We investigated 11 age-matched controls and 14 aneurysmal SAH patients that comprised 10 patients with World Federation of Neurological Societies (WFNS) grade V and 4 patients with WFNS grade II. Employing TR-NIRS, we measured the cortical oxygen saturation (CoSO2) and baseline Hb concentrations in the middle cerebral artery territory. The CoSO2 and Hb concentrations remained stable after SAH in 6 patients; digital subtraction angiography (DSA) did not reveal vasospasm in these patients. In 8 patients, however, CoSO2 and total Hb decreased abruptly between 5 and 9 days after SAH. DSA revealed diffuse vasospasms in 6 of 8 patients. The reduction of CoSO2 predicted occurrence of vasospasm at a cutoff value of 3.9%-6.4% with 100% sensitivity and 85.7% specificity. Trans cranial Doppler (TCD) failed to detect vasospasm in 4 cases, whereas TR-NIRS could. Finally, TRS performed on day 1 after SAH revealed significantly higher CoSO2 than that of the controls (p = 0.048), but there was no significant difference in total Hb. TRS detected vasospasm by evaluating the CBO in the cortex and may be more sensitive than TCD, which assesses the blood flow velocity in the M1 portion. TRS may be useful for the diagnosis of ischemic events in stroke patients.     

Assessment of cerebral blood flow velocities in pre and post angiographic states with transcranial doppler

The frequency of complications resulting from angiograms reported in the literature vary between 0.2-5 percent. This study was planned to determine the changes in cerebral blood flow velocity before and after angiography, using transcranial doppler in patients of subarachnoid hemorrhage (SAH) undergoing angiographies. Thirty patients with subarachnoid hemorrhage underwent transcranial doppler ultrasonography immediately before and after angiography. Nonionic water-soluble agents were used during the angiograms. The mean flow velocity (MFV) and pulsatility index (PI) at the M1 segment of both middle cerebral arteries was simultaneously measured. When the patients (11 male, 19 female, mean age+SD; 52.45+12.06) were compared according to changes in MFV and PI, pre and post-angiography, there was no statistical difference in MFV (p=0.51 and p=0.99, left and right side respectively), and in PI (p=0.48 and p=0.66) pre and post angiography. Although angiogram can be used to detect vasospasm in SAH, it can also be cause of vasospasm, partially due to the effect of the contrast agent on the cerebral arteries. This study proposes that the angiographic method is still safe and TCD can be used to follow up any possible changes in diameter of cerebral arteries before and after angiography.