Table 1. Acute interventions and secondary prevention strategies of proven benefit based on level I evidence.
| Category | Evidence Level | Intervention | Initial or Important Study, Year [Reference] | RRR | ARR | NNT1 |
| Acute stroke | Proven | Stroke unit | Langhorne et al., 1993 [10] | 6.5% | 3.8% | 26 |
| Thrombolysis (tPA) | NINDS, 1995[58] | 9.8% | 5.5% | 18 | ||
| Aspirin | IST, 1997[59] | 2.6% | 1·2% | 83 | ||
| Decompression surgery for IS | Vahedi et al., 2007 [9] | 48.8% | 23% | 4a | ||
| Under evaluation | Recombinant factor 7 for ICH | Mayer et al., 2005[60] | — | — | — | |
| Surgery for ICH | Mendelow et al., 2005[61] | — | — | — | ||
| Extending time window for thrombolysis | DIAS, 2005[62] | — | — | — | ||
| Sonothrombolysis | Alexandrov et al., 2004[63] | — | — | — | ||
| Thrombectomy | MERCI, 2005[32] | — | — | — | ||
| Blood pressure lowering | ENOS, 2007[64] | — | — | — | ||
| Neuroprotection | SAINT, 2006[65] | — | — | — | ||
| Secondary prevention | Proven | Aspirin | Canadian Co-op Study Group[66] | 13.0% | 1.0% | 100 |
| Aspirin plus dipyridamole | Diener, 1996[67] | 15.0% | 1.9% | 53 | ||
| Clopidogrel | CAPRIE, 1996[68] | 10.0% | 1.6% | 62 | ||
| Anticoagulants | EAFT, 1993[69] | 66.0% | 8.0% | 11 | ||
| Carotid endarterectomy | NASCET, 1991[70]; ECST, 1991[71] | 44.0% | 3.8% | 26 | ||
| Blood pressure lowering | PROGRESS, 2001[72] | 28.0% | 4.0% | 97b | ||
| Cholesterol lowering | SPARCL, 2006[73] | 16.0% | 2.2% | 220b | ||
| Under evaluation | Angioplasty | Yadav et al, 2004[74] | — | — | — | |
| Thrombin inhibitors | RELY, 2009 [14] | — | — | — |
The number needed to treat (NNT1) to prevent one stroke patient dying or becoming dependent (acute stroke), or to prevent one fatal or non-fatal stroke (secondary prevention), per year, are given. All figures are approximate and derived from previous analyses, the Cochrane database, or individual trials if these are the only data available. Modified from Donnan et al. [2],
a
NNT for survival with mRS≤3.
b
Calculations based on mean follow-up of 3.9 y in PROGRESS (NNT3.9 = 25) and median 4.9 y in SPARCL (NNT4.9 = 45).
ARR, absolute risk reduction; ICH, intracerebral haemorrhage; IS, ischaemic stroke; NNT, number needed to treat; RRR, relative risk reduction.