Angio negative findings in patients

with spontaneous subarachnoid hemorrhageJose Daniel Flores Sánchez

MR I NeurocirugíaHNGAI

Angio negative findings in patientswith spontaneous subarachnoid

hemorrhage• 75% - Causa aneurismática• 5% - MAV• 20% - No lesión vascular evidente en angiografía.

Van Gijn J, Kerr RS, Rinkel GJ. Subarachnoid haemorrhage. Lancet 2007;369:306 18.‑

• Many authors have advocated a repeat angiogram after a defined time period to detect these missed cases The repeat angiogram (digital subtraction angiogram [DSA]) has got its own set of complications (SAH specific mortality in 0.17% of patients, focal neurological deficit in 3.2% of ‑patients, with permanent disability in 0.04%)

Kaufmann TJ, Huston J 3rd, Mandrekar JN, Schleck CD, Thielen KR, Kallmes DF. Complications of diagnostic cerebral angiography: Evaluation of 19,826 consecutive patients. Radiology 2007;243:812 9.‑

Angio negative spontaneous subarachnoid hemorrhage

• A number of possible factors leading to nonvisualization of a structural lesion, when it is actually present, have been mentioned in the literature, these include:• Blood in cistern obscuring the aneurysm• Vasospasm proximal and distal to aneurysm leading to nonfilling of aneurysm• Vascular thrombosis, thrombus inside the aneurysmal sac • Small micro aneurysm• Very close proximity to skull bone • Hemorrhage from A venous system or simply A technically inadequate examination

-Kumar R, Das KK, Sahu RK, Sharma P, Mehrotra A, Srivastava AK, et al. Angio negative spontaneous subarachnoid hemorrhage: Is repeat angiogram required in all cases?. Surg Neurol Int 2014;5:125-McMahon J, Dorsch N. Subarachnoid haemorrhage of unknown aetiology: What next? Crit Rev Neurosurg 1999;25;9:147 55‑

• With technical advancements, such as three dimensional rotational DSA (3 D ‑rDSA), the recent incidence of DSA negative SAH has shown a significant ‑reduction. This technique is better than conventional two dimensional (2D) angiogram in detecting aneurysm. Ishihara et al.[9] reported that the incidence of DSA negative SAH was 8.6% in the DSA group and 4.2% in the 3 D rDSA group.‑ ‑

Ishihara H, Kato S, Akimura T, Suehiro E, Oku T, Suzuki M. angiogram negative subarachnoid hemorrhage in the era of three ‑dimensional rotational angiography. J Clin Neurosci 2007;14:252 5‑

• The overall incidence of neurological deficits due to procedural complications during DSA has been reported to be around 1 2.6%, ‑with an incidence of persistent deficits following cerebral angiography of about 0.1 0.5%. The nonneurologic complications include: ‑• Renal failure (0 0.15%)‑• Arterial occlusion requiring surgical thrombectomy or thrombolysis (0 0.4%)‑• Pseudo aneurysm formation (0.01 0.22%)‑• Hematoma formation requiring transfusion or surgical evacuation

(0.26 1.5%).‑Kaufmann TJ, Huston J 3rd, Mandrekar JN, Schleck CD, Thielen KR, Kallmes DF. Complications of diagnostic cerebral angiography: Evaluation of 19,826 consecutive patients. Radiology 2007;243:812 9.‑

Negative CT angiography findings in patients with spontaneous subarachnoid hemorrhage: When is digital subtraction angiography still needed?

• Different authors have described various patterns of bleed in SAH. Agid et al. divided these patients into four groups as per the distribution of subarachnoid blood on plain CT of head at the presentation:

I. Perimesencephalic hemorrhage (PMH)II. Diffuse aneurysmal patternIII. Xanthochromic CSF on lumbar puncture with no blood demonstrated on CTIV. Peripheral sulcal pattern (with absence of basal cisternal blood).

Agid R, Andersson T, Almqvist H, Willinsky RA, Lee SK, terBrugge KG, et al. Negative CT angiography findings in patients with spontaneous subarachnoid hemorrhage: When is digital subtraction angiography still needed? AJNR Am J Neuroradiol 2010;31:696 705.‑

Negative CT angiography findings in patients with spontaneous subarachnoid hemorrhage: When is digital subtraction angiography still needed?

• Those patients who had evidence of perimesencephalic hemorrhage presented in good clinical grade (Hunt and Hess scale 1) with headaches, no neurological deficits, no loss of consciousness, and have a good prognosis. Agid et al. suggested that these patients do not need any investigations except an initial CTA.

• The second group of patients were those with diffuse aneurysmal pattern of blood on CT. These patients have a potential risk for re bleeding and have more significant symptoms ‑at onset, and relatively poor prognosis and the possible causes include an extremely small aneurysm, dissection of arterial wall not detected on DSA, or rupture of an artherosclerotic wall.

• The third group with no evidence of SAH on plain CT but diagnosed on lumbar puncture were negative for both CTA and/or DSA, which were clinically similar to first group with a low re bleed risk. ‑

• The fourth group with peripheral sulcal blood were suggestive of vasculitis.

• Ahn SY et al: They concluded that thick or diffuse SAH on initial CT scan was suggestive of an aneurysmal bleed and a repeat angiogram is mandatory if initial angio was negative. They also found CTA useful in the detection of occult aneurysm early in the course of SAH.

Ahn SY, Lim DJ, Kim SH, Kim SD, Hong KS, Ha SK, Clinical analysis of patients with spontaneous subarachnoid hemorrhage of initial negative angiography. Korean J Cerebrovasc Surg 2011;13:230 4.‑

• Other authors have also advocated repeat angiogram in nonperimesencephalic pattern of SAH and advised against the same in perimesencephalic bleeds.

Kumar R, Das KK, Sahu RK, Sharma P, Mehrotra A, Srivastava AK, et al. Angio negative spontaneous subarachnoid hemorrhage: Is repeat angiogram required in all cases?. Surg Neurol Int 2014;5:125

• Classic (diffuse) SAH pattern of SAH is usually associated with fair chances of an ‑underlying missed pathology and also a relatively poorer outcome. We recommend a repeat angiogram in all these patients with rotational angiogram in order to exclude aneurysms, which is important for reducing morbidity and mortality due to misdiagnosis.

Kumar R, Das KK, Sahu RK, Sharma P, Mehrotra A, Srivastava AK, et al. Angio negative spontaneous subarachnoid hemorrhage: Is repeat angiogram required in all cases?. Surg Neurol Int 2014;5:125

Agid R, Andersson T, Almqvist H, Willinsky RA, Lee SK, terBrugge KG, et al. Negative CT angiography findings in patients with spontaneous subarachnoid hemorrhage: When is digital subtraction angiography still needed? AJNR Am J Neuroradiol 2010;31:696 705.‑

RECOMMENDATIONS  — UpToDate ® 2013.  Farhan Siddig, MD. Jose Biller, MD. Amir S Khan, MD

• An estimated 15 to 20 percent of patients with subarachnoid hemorrhage (SAH) are nonaneurysmal. The causes of nonaneurysmal SAH (NASAH) are potentially diverse, and the mechanism of bleeding in these cases is often not identified.

• Perimesencephalic  NASAH make  up  the  majority  of  NASAH  in  some  case  series.  These  have  a  distinctive appearance on computed tomography and a benign course. 

• Other causes of NASAH include occult aneurysm, intracranial or spinal vascular malformations, and intracranial arterial dissection. Less common etiologies include sickle cell disease, pituitary apoplexy, cocaine abuse, cerebral venous thrombosis, and bleeding disorders.

• We recommend repeating DSA within 4 to 14 days after an initial negative study, because of the risk of a false negative. (Up to 24 percent of all SAH patients with initial negative angiography have an aneurysm found on repeat angiography. This may increase to as much as 49 percent if patients with perimesencephalic SAH and patients with normal CT scans are excluded)

• Patients with negative angiography should undergo gadolinium-enhanced magnetic resonance imaging (MRI) of brain and spinal cord.

• Some patients will not have an etiologic diagnosis after DSA and MRI. If rebleeding occurs in such patients, further diagnostic interventions may include further angiographic study of the brain and/or spinal cord, and/or surgical exploration.

• Complications of aneurysmal SAH, hydrocephalus, vasospasm and cerebral ischemia, seizures, hyponatremia, and cardiac abnormalities also occur in NASAH. In this regard, patients with NASAH should be managed similarly to aneurysmal SAH.

• Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PM-NASAH) refers to a subset of SAH patients with characteristic pattern of localized blood on computed tomography (CT), normal cerebral angiography, and a benign course.

• Between 4 and 9 percent of perimesencephalic SAH are caused by rupture of an aneurysm arising from the posterior circulation. Most of the remainder of PM-NASAH do not have an identified etiology.

• The clinical presentation of PM-NASAH overlaps with aneurysmal SAH with abrupt onset of headache, meningismus, photophobia, and nausea. As a group, patients with PM-NASAH have milder clinical features than those with aneurysmal SAH.

• The CT findings that define perimesencephalic SAH include blood isolated to the perimesencephalic cisterns anterior to the brainstem; there may be extension into the ambient cisterns or basal parts of the sylvian fissures, but not into the lateral sylvian fissure, anterior interhemispheric fissure, or lateral ventricles.

• An intracranial aneurysm should be excluded in all patients with perimesencephalic SAH. We suggest using digital subtraction cerebral angiography (DSA). In centers that have a large experience with reliable CT angiography (CTA), this may replace DSA. Repeat angiography should be done in patients in whom concerns for underlying aneurysm remain because of underlying vasospasm or the technical quality of the initial study. Patients who have recurrent bleeding should also have a repeat study. We also recommend a follow-up CTA in all patients one week after the onset of PM-SAH.

• Aside from monitoring, specific treatments are not required for patients with PM-NASAH. However, until a cerebral aneurysm has been excluded on follow-up imaging, we suggest using prophylactic nimodipine to ameliorate complications of potential vasospasm (Grade 2B).

• The long-term prognosis for patients with PM-NASAH is in general excellent.