MIAMI BEACH – Deployed stents produced unexpectedly good outcomes in a series of 19 stroke patients with large-vessel occlusions that resisted recanalization by more conventional treatments.
"Stenting is a safe and very effective option," Dr. Italo Linfante said at the annual International Symposium on Endovascular Therapy. In the series of 19 patients he reported, 8 (42%) had a modified Rankin score of 2 (slight disability) or less at 90 days after stent placement after failing recanalization with intra-arterial tissue plasminogen activator (tPA) as well as treatment with either the Merci clot retriever or the Penumbra clot suction device. Without stent treatment as a last resort, expected mortality in the series would have been about 90%, said Dr. Linfante, director of interventional neuroradiology at the Baptist Cardiac & Vascular Institute in Miami Beach. This series included five deaths – a 26.3% mortality.
"These are desperate cases." When clot lysis or removal fails "there is nothing else to do" but try stent deployment or stent placement and retrieval, Dr. Linfante said in an interview. For patients with large-vessel occlusions "We usually try one or two passes with a device," either Merci or Penumbra, but this fails in about 40% of patients, who then immediately become candidates for stenting.
Stenting was also relatively safe, with no device-related complications. The five deaths comprised three patients who died from hemorrhagic transformations and two who died from large ischemic infarctions. Dr. Linfante attributed the hemorrhages to delayed recanalization rather than to any stenting-related problems.
"Some patients had huge strokes. You can open their arteries beautifully, but it’s too late because by the time you have tried everything else and then go to a stent you’re already 2 hours into the procedure. Then when you open the artery it’s either too late or the patient bleeds," he said.
Selected patients with large-vessel strokes are likely good candidates for immediate stenting, an approach that would avoid delaying treatment with failed attempts to remove the clot, he added. But currently, no evidence-based method exists for identifying which stroke patients with large-vessel occlusions are likely to fail conventional clot-removal treatments. In Dr. Linfante’s experience, clot removal typically fails in patients with occlusions that also involve a substantial amount of plaque. As experience with acute stroke stenting grows and more reports appear in the literature it will become easier to skip an attempt at clot removal in such patients and proceed directly to stenting, he said.
Dr. Linfante treated the 19 patients in his series during August 2008-September 2010. They ranged in age from 28-91 years, with an average age of 65 years. Their average NIH stroke scale score was 18, with one patient having a score as high as 28. All had complete obstructions with no blood flow in their affected vessel. Ten patients had obstructions at the M1 level of the middle cerebral artery; in four, the block occurred at the terminus of the internal carotid, three had occlusions of their basilar artery, and two had tandem occlusions in both the middle and internal carotid arteries. Despite the time needed for the initial, failed attempts at clot removal, 14 patients underwent stenting within 8 hours of symptom onset. Thirteen patients received a Wingspan stent (Boston Scientific), the only stent with approval from the Food and Drug Administration for use in stroke occlusions, Dr. Linfante said. In six patients, vessel tortuosity prevented deployment of a Wingspan stent and so he used an Enterprise stent (Codman).
In 13 patients (68%), stenting resulted in TIMI 3-level blood flow through the affected vessel, and in another five patients it produced TIMI 2 flow. In the final patient from the series stenting led to TIMI 1 flow. In addition to the eight patients who had a modified Rankin score of 2 or less 90 days after treatment, another four patients had a modified Rankin score of 3 (moderate disability) at follow-up.
Dr. Linfante said that he has served as a speaker for or as a consultant to Codman (the company that markets the Enterprise stent), Micrus Endovascular, and Surpass Medical.