The sudden demise of dual renin-angiotensin system blockade or the soft science of the surrogate end point.

Physicians have embraced the concept of dual renin-angiotensin system (RAS) blockade hoping that it would translate into better blood pressure control as well as incremental nephroprotective and cardioprotective effects. With regard to blood pressure, a small additional fall with dual RAS blockade was observed when compared with that seen in monotherapy. Numerous studies have shown a reduction of albuminuria with dual RAS blockade.