It’s always mildly entertaining when stroke neurologists flip hats – from espousing the success of tPA to promoting the Next Big Thing. This is when you hear tPA’s greatest proponents admitting “only 20% to 30% of patients have complete recanalization within 2 hours of intravenous tPA” or “one third of those with any recanalization experience reocclusion.”
Ah, sigh.
But, regardless, this study is about the Next Big Thing – which is a transcranial sonothrombolysis helmet. This safety evaluation of 20 patients starts with IV tPA as indicated, and then continues with this operator-independent 2-MHz pulsed-wave ultrasound through a special headband. The theory, of course, is there will be gaseous microbubbles at the site of occlusion that increase efficacy of tPA and further prevent reocclusion. This safety study had a primary endpoint of 10% symptomatic intracranial hemorrhage with a power of 0.80.
Good news! There were no episodes of sICH. But, however, 6 out of 20 (30%) had asymptomatic ICH. And, then, in the ultimate safety outcome – there were 4 deaths resulting from the 14 other serious adverse events. These deaths were mostly progression of cerebral edema and related consequences, and the authors state they were unrelated to the study device.
The first author is on the scientific advisory board for the device manufacturer – which is not disclosed in the text. The second author holds the patent for the device and is Chair of their scientific advisory board. The Texas Board of Regents is the asignee for the patent for the device, and is one of two sponsoring institutions. And, as the authors note, “other limitations include possible selection bias and investigators unblinded to treatment.”
The median NIHSS was 15, so some poor outcomes are to be expected – but, still, I think this is only convincingly safe if you have financial conflicts of interest.
“CLOTBUST-Hands Free – Pilot Safety Study of a Novel Operator-Independent Ultrasound Device in Patients With Acute Ischemic Stroke”
http://www.ncbi.nlm.nih.gov/pubmed/24159060