Repeat angiography worthwhile in subarachnoid hemorrhage

By Eleanor McDermid, Senior medwireNews Reporter

A second or even third attempt at catheter angiography may reveal vascular abnormalities after an initial negative result in patients with subarachnoid hemorrhage (SAH), say researchers.

However, diagnostic success after initial failure was limited to patients with non-perimesencephalic (PM) SAH, report Stavropoula Tjoumakaris (Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA) and co-workers.

They conducted repeat angiograms in 254 patients at 1 week after the initial negative result. Ten patients had a vascular source of SAH identified at this point, giving a diagnostic yield of 3.9%.

The team repeated catheter angiography for a third time in 174 patients with two negative angiograms at 6 weeks after the initial negative result. Seven had a vascular source, giving an estimated yield of 4.0% for the third angiogram.

Vascular lesions were missed at the first or second angiogram for a variety of reasons including the lesion not filling with contrast in five cases, suboptimal angiographic projection in four cases, and a partially thrombosed aneurysm in three cases.

The researchers did not identify a vascular source of SAH on repeat angiography in any of the 118 patients with PM SAH, "which may call into question the necessity of subsequent angiography… in this patient population."

They also note that most patients with PM SAH have good clinical outcomes, further questioning the need for aggressive diagnostic workup in the face of a negative angiogram.

Considering the 136 non-PM SAH patients alone, the diagnostic yield of the second and third angiograms combined was 12.5%, with the second and third angiograms individually giving similar yields of 7.3% and 7.8%, respectively.

These patients had higher rates of vasospasm and hydrocephalus requiring external ventriculostomy or shunting than the PM SAH patients. Moreover, two had clinically significant rebleeding.

"These patients are of great concern and provide the rationale for a complete diagnostic workup for a vascular source to prevent such potentially life-devastating events," write Tjoumakaris et al in Neurosurgery.

But they caution that their proposed protocol, of repeat angiography and 1 and 6 weeks, "should be carried out in institutions with low angiographic complication rates."

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