Neurological complications after thrombolytic treatment for acute myocardial infarction: emphasis on unprecedented manifestations

Estimation of seizures prevalence in ischemic strokes after thrombolytic therapy

PURPOSE

Post stroke seizures are a complication that occur in 5-20% of acute ischemic stroke (AIS) patients, cause a reduction in quality of life and a greater burden on the health system. There is not enough data regarding an association between today's standard of care treatment in AIS: recombinant tissue plasminogen activator (r-tPA) and the risk for post stroke seizures. Our aim in this work is to reveal such a connection.

METHOD

A non-randomized retrospective cohort-controlled study of 234 patients, who were hospitalized with acute ischemic stroke at Kaplan Medical Center in the years 2009-2015 and were divided into two different treatment groups: r-tPA and antiaggregant therapy(n = 141) and antiaggregant therapy only (n = 95) was conducted by us. Information regarding demographics, medical history, nature of the event, including NIHSS values on admission, discharge, and post stroke seizures, were obtained for each group. Follow-up was done for one year.

RESULTS

During the year of follow-up, 19 patients (8.1%) of the overall cohort, developed seizures: 12 of them (12.6%) belonged to the control group and 7 (5%) to the study group p < 0.05). Results showed a decrease in the risk for developing seizure when treated with r-tpA, comparing to antiaggregants (odds ratio = 0.64).

CONCLUSION

This study suggests there is an association between r-tPA treatment and reduction of the risk for post stroke seizures.

Three-dimensional structure of fibrolase, the fibrinolytic enzyme from southern copperhead venom, modeled from the X-ray structure of adamalysin II and atrolysin C

The fibrinolytic enzyme from southern copperhead snake venom, fibrolase, contains 1 mole of zinc per mole of protein, belongs to the major family of metalloproteinases known as the metzincins, and has been shown to degrade fibrin clots in vitro and in vivo. The purpose of this study was to develop a 3-dimensional model of fibrolase to investigate the geometry of conserved and variable sequences between members of the snake venom metalloproteinases. When compared to atrolysin C (form D) or adamalysin II (metzincins with completely different substrate specificity), fibrolase has approximately 60% overall sequence identity and nearly 100% sequence similarity in the active site. We used the crystal structure of adamalysin II to build a 3-dimensional homology model of fibrolase. Three disulfide bonds were constructed (the highly conserved disulfide bond [118-198] was maintained from the adamalysin II structure and 2 new disulfide bonds were introduced between residues 158-182 and 160-165). We used Sculpt 2.5 and HyperChem 5.0 to "dock" a substrate fragment octapeptide (HTEKLVTS), and a water molecule into the active site cleft. We calculated the differential average homology profile for fibrolase compared to 8 hemorrhagic and 5 nonhemorrhagic metzincins. We then determined the sequence regions that might be responsible for their substrate specificity. Our 3-dimensional homology model shows that the variable sequences lie on the periphery of the identified active site region containing the His triangle; this indicates that substrate specificity may depend on surface residues that are not directly associated with the active site.

An autopsy case of intracranial hemorrhage during tissue plasminogen activator infusion

We describe an autopsy case of severe intracranial hemorrhage which occurred during the infusion of tissue plasminogen activator (t-PA) for acute myocardial infarction. A 75-year-old man was admitted with substernal chest pain of 3-h duration and electrocardiographic changes consistent with an acute inferior myocardial infarction. Physical examination was unremarkable, except for an initial blood pressure reading of 160/96 mmHg. The patient received 3,000 IU intravenous heparin followed by a 2.4 x 10(6) IU bolus dose of tissue plasminogen activator (t-PA) (Alteplase). This was followed by a drip infusion of 21.6 x 10(6) IU of t-PA over 1 h (total dose 41 mg). Thirty minutes after the infusion of t-PA was initiated, the patient suddenly lost consciousness and began to have violent convulsions, followed by cardiac arrest. Autopsy revealed massive hemorrhage in the bilateral cerebrum and brain stem. To our knowledge, this is the first case of sudden death during t-PA infusion therapy.