The Yield of Repeat Angiography in Angiography-Negative Spontaneous Subarachnoid Hemorrhage

Abstract

Objective Despite the technological advancement in imaging, digital subtraction angiography (DSA) remains gold standard imaging modality for spontaneous subarachnoid hemorrhage (SAH). But even after DSA, around 15% of SAH remains elusive for the cause of the bleed. This is an institutional review to solve the mystery, “when is second DSA really indicated?” Methods In a retrospective review from January 2015 to December 2017, we evaluated cases of spontaneous SAH with initial negative DSA with repeat DSA after 6 weeks to rule out vascular abnormality. The spontaneous SAH was confirmed on noncontrast computed tomography (NCCT) and divided into two groups of perimesencephalic SAH (PM-SAH) or nonperimesencephalic SAH (nPM-SAH). The outcome was assessed by a modified Rankin’s score (mRS) at 6 months postictus. Result During the study period, we had 119 cases of initial negative DSA and 98 cases (82.3%) underwent repeat DSA after 6 weeks interval. A total of 53 cases (54.1%) had PM-SAH and 45 cases (45.9%) had nPM-SAH. Repeat DSA after 6 weeks showed no vascular abnormality in 53 cases of PM-SAH and in 2 (4.4%) out of 45 cases of nPM-SAH. At 6 months postictus, all cases of PM-SAH and 93% of nPM-SAH had mRS of 0. Conclusion We recommend, a repeat DSA is definitely not required in PM-SAH, but it should be done for all cases of nPM-SAH, before labeling them as nonaneurysmal SAH. Although the overall outcome for nonaneurysmal spontaneous SAH is better than aneurysmal SAH, nPM-SAH has poorer eventual outcome compared to PM-SAH.

Angionegative Subarachnoid Hemorrhage: Need for Consensus Guidelines

“…Both the abnormalities were minor irregularities in a vessel which did not require any surgical intervention, and both were noted in patients with nPM-SAH. 1 This finding is at variance with a recent meta-analysis on the yield of a repeat angiography, which revealed a pick up rate of approximately 10% in nPM-SAH, and 1.6% for patients with perimesencephalic SAH. 3 These conflicting reports add to the controversies related to angionegative SAH which can be summarized as follows:…”

“…In approximately 10 to 20% cases of spontaneous nontraumatic subarachnoid hemorrhage (SAH), no underlying vascular etiology is found and the source of hemorrhage remains unknown. 1,2 This angionegativity has been ascribed to various factors including venous bleeds, hypertension, alcoholism, and drug abuse. However, these need to be a diagnosis of exclusion and to be considered only after ensuring the absence of an aneurysm.…”

“…The authors of this manuscript share their experience with 119 angionegative SAH patients and discuss the dilemmas in management of such patients. 1 Their concluding suggestion to perform a repeat digital subtraction angiography (DSA) for all patients with nonperimesencephalic (nPM)-SAH at 6 weeks after the initial bleed appears to be the most appropriate protocol with the currently available level of evidence.…”

“…With a pooled sensitivity and specificity of 98 and 100%, CTA has now replaced DSA as the first mode of investigation in almost all centers and DSA is reserved for patients with suspicious CTA findings. 1 In spite of being the gold standard, DSA has the drawback of being operator and interpretation dependent, and aneurysms may be missed even on biplane DSA. 4 DSA may miss an aneurysm due to copious cisternal blood obscuring the aneurysm, vasospasm, thrombosis, small size of the aneurysm, or simply due to a technically inadequate examination.…”

Factors determining outcome of post-angiogram-negative subarachnoid hemorrhage

“…[ 29 ] The overall outcome for non-aneurysmal spontaneous SAH is better than aneurysmal SAH, but nPM-SAH has a poorer eventual outcome compared to PM-SAH, therefore repeat DSA should be done for all cases of nPM-SAH, before labeling them as non-aneurysmal SAH. [ 30 ]…”