1 / 17

Tissue Plasminogen Activator for Acute Ischemic Stroke

Tissue Plasminogen Activator for Acute Ischemic Stroke. National Institute of Neurological Disorders and Stroke rt -PA Stroke Study Group. Summarise the paper in 200 words. Summarise the paper in 200 words. Aims

wacevedo
Télécharger la présentation

Tissue Plasminogen Activator for Acute Ischemic Stroke

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Tissue Plasminogen Activator for Acute Ischemic Stroke National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group

  2. Summarise the paper in 200 words

  3. Summarise the paper in 200 words • Aims • Compare intravenous tissue plasminogen activator (t-PA) with placebo in treatment of acute ischaemic stroke. • Method • 2 part double blinded multi-centre randomised controlled trial • Patients with ischaemic stroke (no intracranial haemorrhage on CT) within 3 hours of onset were included • Stratified block randomisation to treatment with placebo or t-PA

  4. Summarise the paper in 200 words • Outcome measures: • Part 1: Complete resolution of neurological deficit or improvement in NIHSS score >4 within 24 hours of onset of stroke • Part 2: Recovery with minimal or no deficit 3 months after treatment, measured using a combination of 4 outcome measures (Barthel index, modified Rankin scale, Glasgow outcome scale, NIHSS)

  5. Summarise the paper in 200 words • Results • Part 1 (n=291): no significant difference in percentage of patients with neurological improvement at 24 hours (relative risk =1.2 (95% CI 0.9-1.6)) • Part 2 (n=333): Odds ratio for favourable outcome in combined test statistic at 3 months in t-PA group =1.7 (95% CI 1.2-2.6, p=0.008) • No significant difference in mortality, but higher rate of symptomatic intracerebral haemorrhage within 36hrs seen in t-PA group (p<0.001)

  6. Summarise the paper in 200 words • Conclusion • Despite an increased incidence of symptomatic intracerebral hemorrhage, treatment with t-PA within 3 hours onset of ischemic stroke improved clinical outcome at 3 months.

  7. Abstract

  8. The Good... • Multi-centre RCT • Clear power calculation performed • Few patients lost to follow up • Intention to treat analysis

  9. The Bad... • Patient selection – were all eligible patients randomised? • No CONSORT diagram • Differences between placebo and treatment groups • No mean given for NIHSS score - makes comparison difficult • Higher rate of “Large-vessel occlusive stroke” in placebo group • Higher rate of edema and mass effect in placebo group • Unconventional statistical tests applied • (Mantel-Haenszel test and Wald test) • No p-value given for differences in adverse events • (symptomatic intracerebral haemorrhage and serious systemic bleeding)

  10. The Bad... • Dichotomous end-point in part 2 • No assessment of magnitude of effect of treatment can be made • Randomisation method • Permuted block design with blocks of various sizes. Stratified by clinical centre (8 centres) and time to treatment • Was part 2 only done because part 1 failed to deliver a significant outcome?

  11. Definitions • Control event rate (CER) = C/(C+D)= outcome event rate in control group • Experimental event rate (EER) = A/(A+B) = outcome event rate in experimental group

  12. Definitions • Control event rate (CER) = C/(C+D) • Experimental event rate (EER) = A/(A+B) • Absolute risk reduction (ARR) = CER-EER • Relative risk (RR) = EER/CER • Relative risk reduction (RRR) = (CER-EER)/CER

  13. Definitions • Number needed to treat (NNT) • The number of subjects that must be treated with the intervention, compared with the control, for one extra subject to experience the beneficial effect. • NNT = 1/ARR

  14. Definitions • Control event rate (CER) = C/(C+D) • Experimental event rate (EER) = A/(A+B) • Absolute risk reduction (ARR) = CER-EER • Relative risk (RR) = EER/CER • Relative risk reduction (RRR) = (CER-EER)/CER • Number needed to treat (NNT) = 1/ARR

  15. Bonus Points • Using the numbers given for the Barthel index in part 2 of the study (Table 4), calculate the number needed to treat (NNT) in order to get a favourable functional outcome. • Absolute risk reduction = 50-38 =12% • NNT= 1/ARR = 1/0.12 = 8.3

  16. Bonus Points • Using the data given in Table 6, calculate the overall number needed to harm (NNH) for symptomatic intracranial haemorrhage (parts 1 and 2 of the study combined). • Risk of symptomatic intracranial haemorrhage • t-PA group = (8+12)/(144+168) = 0.064 = 6.4% • Placebo = (0+2)/(147+165) = 0.006 = 0.6% • Absolute risk reduction = 6.4-0.6 = 5.8% • NNH = 1/ARR = 1/0.058 = 17.2

  17. Further analysis of stroke thrombolysis: www.thennt.com/thrombolytics-for-stroke/

More Related