The NOR-SASS study of Aliona Nacu and co-workers shows no additional clinical benefit following treatment with ultrasound and injection of gaseous microbubbles in stroke patients eligible for thrombolysis.


  1. Contrast-enhanced sonothrombolysis is safe in unselected patients with ischemic stroke.
  2. Contrast-enhanced sonothrombolysis does not reduce the risk of intracerebral hemorrhage or short-term mortality compared to conventional thromolysis with tissue plasminogen activator alone.
  3. Contrast-enhanced sonothrombolysis does not improve the functional outcome following ischemic stroke.


Thesis: The Norwegian Sonothrombolysis in Acute Stroke Study (NOR-SASS). Randomised controlled contrast-enhanced sonothrombolysis in a general acute ischaemic stroke population
Candidate: Aliona Nacu
Time: October 27, 2017 at 12:15
Place: Haukeland University Hospital, BB-building: Auditorium 4
Link to university website (in Norwegian)


(1) Sonothrombolysis accelerates clot break-up both without and when combined with thrombolysis with tissue plasminogen activator. The effect might be potentiated by adding intravenous gaseous microbubbles. The Norwegian Sonothrombolysis in Acute Stroke Study (NOR-SASS) aimed to assess the effect and safety of contrast-enhanced ultrasound treatment in unselected patients with acute ischemic stroke.

(2) The results show that contrast-enhanced sonothrombolysis is safe for both ischemic stroke patients with and without a visible occlusion on CT angiography. No significant clinical effect of sonothrombolysis was found for the primary end points of neurological improvement at 24 hours and functional handicap at 90 days. Furthermore, no effect of treatment was seen regarding risk of hemorrhage or short-term mortality.

NOR-SASS was stopped prematurely due to lack of funding, and the analyses includes 183 patients. The researchers are still aiming to reach to intended number of 276 patients to see if any real treatment effect is masked by the lack of statistical power.


(1) Nacu, A., Kvistad, C. E., Logallo, N., Naess, H., Waje-Andreassen, U., Aamodt, A. H., Solhoff, R., Lund, C., Tobro, H., Rønnine, O. M., Salvesen, R., Idicula, T. T., & Thomassen, L. (2015). A pragmatic approach to sonothrombolysis in acute ischaemic stroke: the Norwegian randomised controlled sonothrombolysis in acute stroke study (NOR-SASS)BMC neurology15(1), 110.

(2) Nacu, A., Kvistad, C. E., Naess, H., Øygarden, H., Logallo, N., Assmus, J., Waje-Andreassen, U., Kurz, K. D., Neckelmann, G., & Thomassen, L. (2017). NOR-SASS (Norwegian Sonothrombolysis in Acute Stroke Study)Stroke48(2), 335-341.

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