Mann et al. However, our ethics committee objected to a design in which crossover was allowed only six months after randomization, because at the time our study was designed, many clinicians regarded angioplasty as a mandatory treatment. Stenting probably improves the anatomical results of angioplasty, but it was not possible to perform stenting at all the participating centers at the time the study was designed. Tan et al. argue that our interpretation of the blood-pressure data was inappropriately negative. However, after three months, when no crossover had occurred, there was no significant difference in blood pressure between the two treatment groups.
Renovascular hypertension is a complicated and controversial matter.
However, including such patients reverses the burden of proof, because there are no reliable tests to identify them. Improvement in hypertension after the stenosis has been relieved is not a workable criterion because of the possible technical failure of angioplasty and the irreversible later phase of renal hypertension and because a diagnosis made in retrospect precludes the selection of patients before the intervention. Brigit C. van Jaarsveld, M.D. Pieta Krijnen, M.Sc. CA Rotterdam, the Netherlands References 1 . Van de Ven PJ, Kaatee R, Beutler JJ, et al.