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Centre for Evidence-
Based Medicine

Example NNTs - Peripheral Vascular Surgery

Condition or Disorder Intervention vs. Control Outcome Follow-up Duration Event Rates % NNT (95% CI)
Acute arterial leg occlusion1 Thrombolysis vs. surgery Amputation- free survival at 6 and 12 months 6 and 12 months 6 months: 25.2
12 months: 30.1
6 months: 28.2
12 months: 35
Not significant
Hemorrhagic complications 5.5 12.5 14 (8 to 47)


  1. N Engl J Med 1998 Oct 15;339(16):1105-11