The original argument: tPA helps all strokes, we must give it to everyone as quickly as possible!
The updated argument: tPA doesn’t not help all strokes, so it should still be given!
Specifically, as applies to the cohort of patients with large vessel occlusions being considered for mechanical thrombectomy. This small, pooled registry sample looked at cases from four centers, evaluating the rate and predictive characteristics for recanalization prior to cerebral angiography. The stated purpose of their study was to develop a predictive score, with the reasonable goal of reducing unnecessary tPA exposures prior to thrombectomy.
The numbers, in their score derivation and validation cohorts:
- ICA: 6.4%/1.0%
- M1 proximal: 16.1%/13.7%
- M1 distal: 30.3%/30.7%
- M2: 33.7%/34.0%
But, an even more powerful a predictor was thrombus length, as measured by T2 MRI susceptibility vessel sign. Recanalization was seen at over 80% for clots <5mm, 30% for 6-10mm, and below 10% for clots longer than 10mm, with particular futility for >20mm.
Interesting data – and a nice look at how not all sites of occlusion and clots are created equal. Whether, and how, we ought to treat them differently remains uncertain until the results of a prospective trial.
“Post-Thrombolysis Recanalization in Stroke Referrals for Thrombectomy”
https://www.ahajournals.org/doi/pdf/10.1161/STROKEAHA.118.022335