[Clonidine therapy of "paradoxical hypertension" following surgery of isolated stenosis of the aortic isthmus in childhood].

In the period from 1974 to 1983, altogether 234 children underwent surgery of isolated coarctation of the aorta at the Heart Center Munich. In 146 of these patients, a reactive increase of blood pressure has been noted following surgery, and in about half of them the blood pressure was considerably elevated above the 95-percentile. Since the success of surgery may be endangered by a critical increase of blood pressure, in 66 patients an antihypertensive therapy with clonidine has been started immediately after operation. By this treatment the intended decrease of blood pressure has been effected within the first two days after surgery, and in 91% of the patients the therapy could be stopped within the first two postoperative weeks. In 6 out of these 66 patients, the "paradoxical hypertension" persisted so that the clonidine therapy had to be continued after discharge from hospital. The empirically determined dosage and the duration of treatment have been modified by the clinical requirements, i.e. by the actual level of the blood pressure. The average duration of drug administration has been lengthened according to the advanced age at time of surgery, while the required clonidine dosage simultaneously showed a tendency to decrease. Since no side-effects have been registered in the course of this procedure, the use of clonidine suggests a promising therapeutical approach to "paradoxical hypertension".