Resistance index [R.I] as a predicitive in the treatment of erectile dysfunction [E.D]

ABSTRACT

The aim of this work is to utilize the Pharmaco-Penile Duplex Ultrasonography [P.P.D.U] as a treatment-directed instead of an etiology-directed approach in cases of Erectile Dysfunction [E.D]. The intended treatment is Intra-Corporeal Injection [I.C.I] therapy using PEi; and the approach aims at 1- nullifying the most feared complication of prolonged erection; and 2- assessing the predictive value of the Resistance Index'[R.I] regarding an adequate erectile response with subsequent dose escalation. 68 cases of [E.D], all have started with a low dose [4mg of PEi] during the [P.P.D.U] and two parameters were traced in all cases 1- the patient's self report of erectile response. And 2- Resistance Index [R.I] a] 8cases[41.8 percent] have achieved an adequate erectile response with this low dose [responders], all have adhered to self-injection therapy and within 4-7 months of follow-up, 75 percent of them experienced recovery of spontaneous erection. b] 40 cases [58.8 percent] failed to achieve an adequate erectile response with the low dose [non-responders], all have adhered to self-injection with dose escalation; 91.6 percent of the cases with R.I > 0.8 [during the initial P.P.D.U test] have achieved an adequate erectile response with dose escalation, while only 12.5 percent of the cases with R.I<0.8 have achieved an adequate erectile response with dose escalation [the maximum dose per injection did not exceed 20mg]. No cases of prolonged erection have been reported. The treatment-directed approach helps to 4 Obviate the risk of prolonged erection. 4 Greatly simplify and nullify the limitation of operator dependency of the [P.P.D.U test] because; It doesn't require the measurement of pre- and post-injection diameters of the small cavernously arteries with its inherent inaccuracy. It relies on the measurement of [R.I], therefore; variations and/or possible errors in measurement of [P.S.V] and [E.D.V] are filtered out in the ratio R.I-P.S.V - E.D.V / P.S.V. R.I > 0.8 strongly predicts an adequate erectile response with subsequent dose escalation