Dear Editor,
We would like to commend the authors Bashir et al. for their study assessing the need for repeat angiography in patients with subarachnoid hemorrhage.1 However, we have a few comments and concerns about the conclusions.
The authors conclude that diagnosis of perimesencephalic subarachnoid hemorrhage (PMSAH) should continue to be confirmed with an initial digital subtraction angiography (DSA), as computed tomographic angiography (CTA) may not be adequate. However, none of the initial or follow-up DSAs in their study group in PMSAH yielded any positive results that CTA might have missed. It is not clear how the authors reached that conclusion about initial DSA.
The authors report a single case with non-PMSAH that rebled after two negative CTAs and one DSA, and was subsequently found to have an anterior choroidal aneurysm 9 days later. Based on this case, the authors state that repeat DSA must be performed in patients with nPMSAH. There has never been a consensus as to when the repeat DSA should be performed, although several studies recommend repeat DSA at 7 days. If the repeat DSA was performed at 7 days in this case, it cannot be said with certainty that this aneurysm would have been detected.
We would also request the authors to comment if the stated aneurysm could be seen in retrospect on the earlier CTAs and DSAs. The bolus and the technique (magnification and obliquity) on the images provided seem different between the initial and follow-up studies, similar to previously reported studies reporting on missed aneurysms on initial studies.2
We have previously reported DSA to be of limited utility in PMSAH after a negative initial CTA, and it is not cost-effective.2,3 The authors state that the meta-analysis was limited due to inconsistent definition of PMSAH used in included studies. It is true that the definition was not consistent or clearly stated in all studies. However, it is unclear how that limits the inference from the meta-analysis.
Although DSA was reported to be safe in this series, it is an invasive procedure and not without reported complications. Especially in patients with PMSAH, both initial and repeat DSA after a negative initial CTA should be used with caution, and recommendations for their use should be based on strong evidence.
Conflict of interest
The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
References
- 1.Bashir A, Mikkelsen R, Sorensen L, et al. Non-aneurysmal subarachnoid hemorrhage: When is a second angiography indicated? Neuroradiol J. Epub ahead of print 20 November 2017. DOI: 10.1177/1971400917743100.
- 2.Kalra VB, Wu X, Matouk CC, et al. Use of follow-up imaging in isolated perimesencephalic subarachnoid hemorrhage: a meta-analysis. Stroke 2015; 46(2): 401–406. [DOI] [PubMed] [Google Scholar]
- 3.Kalra VB, Wu X, Forman HP, et al. Cost-effectiveness of angiographic imaging in isolated perimesencephalic subarachnoid hemorrhage. Stroke 2014; 45(12): 3576–3582. [DOI] [PubMed] [Google Scholar]