- Heo J, Kim S, Lee K, Kim E, Chu C, Nam J. Increase in plasma matrix metalloproteinase-9 in acute stroke patients with thrombolysis failure. Stroke. 2003;34:e48-50 pubmed..The MMP-9 plasma level was significantly higher in patients whose arteries were not recanalized. MMP-9 may be associated with the formation of a thrombolytics-resistant thrombus. ..