Renal Vein Renin in Renovascular Hypertension: The Experience of Two Italian Centers

Abstract

A retrospective analysis of renal vein renin results has been done in 96 patients with renal artery stenosis and hypertension studied in two Italian centers (Sassari and Pisa) with respect to the outcome of either surgery or percutaneous transluminal angioplasty (PTA). In all patients the renal vein renin ratio and the V-A/A ratios for the affected and unaffected kidney were calculated. Each patient underwent surgery (75) of PTA (21) : 71 subjects were cured, 17 improved whereas the arterial pressure did not vary after revascularisation procedure in 8 patients. In the Pisa series all 54 patients showed a lateralisation with contralateral renin suppression and 95% of them benefitted from surgery. In the Sassari series 42 patients were submitted to PTA or surgery, not only on the basis of a positive renal vein renin study but taking into account a complete clinical evaluation: 8 of them were cured or improved in spite of negative renal vein renin criteria. In the two series, the better predictive index appeared to be the suppression of the renin secretion from the contralateral kidney while the high/low renin ratio showed a consistent amount of false-positive and false-negative results. Our retrospective study demonstrates that the renal vein test in hypertensive patients with renal artery stenosis is highly predictive of the curability of the disease, particularly when contralateral suppression of renin secretion is present. On the other hand, since patients with negative renin indexes can also take benefit from surgery of PTA, the renin parameters cannot be adopted as the sole criterion in making the decision to operate.

Prediction of Hypertension Improvement After Stenting of Renal Artery Stenosis

“…With respect to the measurement of renin, a number of series (19,20) have demonstrated that renal vein renin activity increases in patients with renal artery stenosis. Although the renal vein renin assay is possibly beneficial, however, the measurements are impractical to obtain.…”

Renovascular Hypertension with Low-to-Normal Plasma Renin: Clinical and Angiographic Features

“…Low-renin RVH has been reported previously [39] and attributed to renin-independent mechanisms, which may be triggered by renal ischaemia [13] and/ or underestimation of renin levels due to methodological problems in the PRA assay, technical failure, drug interference, an upward shift in the Ang II/BP relationship due to long-standing hypertension, and renal failure [l, 8, 9, 12, 391. The participation of renin-independent mechanisms has been supported by some studies of RVH [13,40,411. In rats with 2 kidney, 1 clip (2 K-1 C) hypertension, MacDonald et al [41] showed that excision of the clipped kidney normalized BP consistently, at variance with the competitive Ang I1 antagonist l-Sar-8-Ala Ang I1 [41].…”

The utility of renal venous renin studies in selection of patients with renal artery stenosis for angioplasty

“…In a series using furosemide as a renin-stimulating agent, no indices of lateralization were found to be predictive of treatment benefit [7]. Other studies with variable protocols and inclusion criteria also failed to show that RVRs are useful in predicting revascularization response [40,41]. On the contrary and more recently, an RVRR of at least 1.55 was found to be useful in identifying patients with RAS more than 70% who benefit from revascularization, while a ratio greater than 1.72 was found to be associated with good outcomes from nephrectomy when renal artery occlusion was present [8].…”