An update to the American Heart Association and American Stroke Association guidelines for the management of aneurysmal subarachnoid hemorrhage places new emphasis on treating patients at high-volume centers with multidisciplinary teams and following up with patients after treatment to detect rebleeding and delayed cerebral ischemia, along with other potential complications.
Those changes are among 21 new recommendations made by the guidelines’ multidisciplinary writing committee, including five class I recommendations where there is high confidence that the benefit from a procedure or treatment greatly outweighs the potential risks. Another nine recommendations from the 2009 guidelines were changed.
Dr. Alejandro A. Rabinstein
"The guidelines in 2009 had to summarize the literature of 15 years [since the first guidelines were published in 1994], and so the development of those guidelines was very complex. It achieved its goal to a good degree, but obviously there were a few aspects to be refined," said Dr. Alejandro A. Rabinstein, vice chair of the guidelines writing committee. He is a vascular neurologist and neurocritical care specialist at the Mayo Clinic, Rochester, Minn.
The revised document primarily covers the literature published between Nov. 1, 2006 – the last date covered in the 2009 guidelines – and May 1, 2010, and does not discuss ongoing studies. The associations plan to update the guidelines every 3 years because "the data presented ... only begin to scratch the surface of the burgeoning knowledge in this fast-developing field," according to the writing committee.
The panel required a consensus to make recommendations "even where there is the best quality of evidence because there may be some difference of opinion even with good research," Dr. Rabinstein said in an interview. The use of a multidisciplinary panel "allows for the possibility of arriving at the same types of positions that you get with the patient at the bedside. It is a multidisciplinary group treating these patients; it is not a single specialty."
The guidelines recommend that low-volume hospitals, such as those with fewer than 10 aneurysmal subarachnoid hemorrhage (aSAH) cases per year, should consider early transfer of patients to high-volume centers, such as those with more than 35 cases per year, that have experienced cerebrovascular surgeons, endovascular specialists, and multidisciplinary neurointensive care services. Hospitals should also perform annual monitoring of complication rates as well as have a credentialing process to make sure that proper training standards have been met by individual physicians treating brain aneurysms (Stroke 2012 May 3 [doi:10.1161/STR.0b013e3182587839]).
"We do not have, like other American Heart Association stroke guidelines, a track record that we can follow. We don’t know exactly how the guidelines are being followed across institutions. Hopefully that’s going to become available by the time the next set of guidelines gets published. But certainly we do know that there is great variation," Dr. Rabinstein said.
Although the panel noted that there "have been only minor changes in imaging technology for this condition" since the previous guidelines, Dr. Rabinstein pointed out that new recommendations clarify the value of noninvasive angiography vs. invasive angiography. CT angiography (CTA) may be considered in diagnosing an aneurysm and may help in deciding which method to repair it with, but when CTA is inconclusive, digital subtraction angiography with three-dimensional rotational angiography is recommended in most cases. MRI modalities may be reasonable if CTA is nondiagnostic, but negative results do not preclude an analysis of cerebrospinal fluid.
Between symptom onset and repair of the aneurysm, the guidelines recommend controlling blood pressure (to a systolic BP of less than 160 mm Hg) with a titratable drug to balance the risk of stroke, hypertension-related rebleeding, and maintaining cerebral perfusion pressure.
Treatment of the ruptured aneurysm with endovascular coiling should be considered when it is judged to be technically amenable to both coiling and microsurgical clipping. Stenting of the ruptured aneurysm should be avoided because of increased morbidity and mortality associated with the procedure.
Dr. Rabinstein noted that the panel put "emphasis on the importance of following up with these patients after their subarachnoid aneurysm is treated to make sure they do not have what we call remnant rebleeding of the aneurysm that could require retreatment," particularly for patients with aneurysms treated with endovascular coiling.
When cerebral vasospasm occurs, new emphasis has been placed on maintaining euvolemia and normal circulating blood volume rather than hypervolemia to prevent delayed cerebral ischemia. Evidence for the use of oral nimodipine for vasodilation is even stronger than before, making it recommended for use in all aSAH patients. Recommendations now suggest that use of transcranial Doppler imaging is reasonable to conduct surveillance for vasospasm and that perfusion imaging with CT or MRI may identify regions of ischemia. Delayed cerebral ischemia should be treated with induced hypertension unless it is elevated at baseline or cardiac status contraindicates its use.