Background The aim of this prospective study was to evaluate the effect of successful renal artery correction (angioplasty or surgery) on intra-renal Doppler flow parameters in hypertensive patients with renal artery stenosis (RAS) and preserved renal function.
Material and methods The study included 30 hypertensive patients (mean age: 53.5 ± 2.0 yrs, range: 33–75 years; 18 males, 12 females) with arteriographically confirmed atherosclerotic RAS. Intra-renal Doppler flow parameters (maximum systolic velocity - Vmax, acceleration - Acc, acceleration time - AcT, pulsatility index - PI and resistive index - RI) were evaluated before (0) and during a one year follow-up period at 1 week (I), 6 months (II) and 12 months (III) after successful renal artery correction (angioplasty or surgery) in hypertensive patients with RAS. 24-hour blood pressure monitoring was performed before and 12 months (at III) after RAS correction. The patients were classified into two groups according to the clinical outcome: Group 1 - cured, with permanent discontinuation of antihypertensive treatment and with 24 h BP of < 135/85 mm Hg following PTRA or surgery without antihypertensive medication; Group 2 - not cured, with antihypertensive treatment maintained or modified but not discontinued.
Results In Groups 1 and 2, taken as whole, a statistically significant decrease in Vmax was observed at I, II and III, as compared to the pre-intervention period. Evaluation of the intra-renal branches in the one year follow-up revealed a decreased Acc value at 0 followed by a statistically significant increase in Acc at I, II and III for the whole group involved in the study, taking Groups 1 and 2 together, as compared to the pre-interventional period. The AcT value for the whole group was increased at 0 and after successful renal artery correction a significant decrease was observed at I, II and III in the whole group and in Group 2. In Group 1 there were no differences in RI value at I, II, and III when compared with the baseline (0.54 ± 0.02, 0.56 ± 0.03, 0.55 ± 0.04 vs. 0.52 ± 0.04 respectively; p = NS). In Group 2 RI values increased non-significantly at I, II, and III, as compared to the pre-interventional period (0.64 ± 0.02, 0.94 ± 0.05, 0.63 ± 0.02 vs. 0.61 ± 0.02 respectively; p = NS). RI values were significantly higher in Group 2 as compared to Group 1 at 0 and I. There were significant differences in PI values between Group 1 and Group 2 before and 6 weeks (I) after successful renal artery correction.
Conclusion Our study indicates that among hypertensive patients with RAS and preserved renal function function successful renal artery correction had no effect on the resistive index and pulsatility index. Of the four indices examined acceleration and acceleration time are useful for evaluating the long-term results of renal angioplasty or surgical treatment in patients with RAS.