MI - STREPTOKINASE AND ASA SAVE LIVES (ISIS-2)

Appraised by: Straus 05 March 1997

Three-part Question:
In pts with suspected MI, does the combination of streptokinase and ASA decrease the risk of death?

Search Terms:
MI, thrombolysis, limited to RCTs

The Study:
Double-blinded concealed randomised controlled trial with intention-to-treat.
pts enrolled within 24 hrs of suspected MI (based on clinical presentation alone) with no clear indication for or contraindication to SK or ASA. Followed up for median of 15 months, 97% follow-up to week 5.
Control group: (N=4292) placebo albumin IV and placebo tablet
Experimental group: (N=4300) SK IV over 1 hr, given within 24 hrs of onset of pain and 162.5 mg of ASA for 1 month.

The Evidence:

Outcome	Time to Outcome	RRR	ARR	NNT
overall mortality at 2 yrs	2 yrs	19%	0.042	24
	95% CI	12% to 27%	0.025 to 0.059	17 to 40
overall mortality at 5 wks	5 wks	40%	0.053	19
	95% CI	30% to 49%	0.040 to 0.066	15 to 25

Comments:

1. for SK alone, NNT of 38 for 2 yr mortality
2. for ASA alone, NNT of 53 for 2 yr mortality and the effects of the combination of these agents appears to be almost additive.
3. the ARI for major bleed in 0.003 (intracranial bleed: 0.001) and the ARR for stroke with SK/ASA is 0.005
4. see also systematic overview of thrombolytic therapy by the FTT group, Lancet 1994;343:311-22.

Expiry date: March/98

References:

1. ISIS-2 Collaborative Group. Randomised trial of intravenous streptokinase, oral aspirin, both or neither among 17187 cases of suspected acute myocardial infarction. Lancet 1988;2:349-60.

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