Altman nomograms were used to calculate the presumed sample size of an actual RCT, arbitrarily assuming a most likely small standardized difference (0.3). With a significant criterion set at 0.05, using a two-tailed test, the number of patients per group, required to have a 90% power is ~500. Therefore, it was decided to carry on a pilot trial, enrolling 40 patients (20 each group), to assess differences in any of the end-points and tailoring the sample size of the larger multicenter RCT accordingly.