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Renal vein renin activity in primary hypertension: variability and influence of contrast material
Insights
The renal vein renin ratio (RVRR) is often used to predict surgery success in hypertension patients. However, this study shows significant overlap between essential and renovascular hypertension, questioning its reliability.
Area of Science:
- Nephrology
- Cardiology
- Hypertension Research
Background:
- The renal vein renin ratio (RVRR) is a key indicator for surgical curability in renal artery stenosis (RAS).
- A threshold of 1.5 for RVRR is commonly believed to predict successful surgical outcomes.
Purpose of the Study:
- To evaluate the diagnostic overlap of RVRR between essential hypertension and renovascular hypertension.
- To assess the impact of angiography contrast material on renal vein renin activity (RVRA).
Main Methods:
- Measured RVRR in 40 patients with essential hypertension.
- Analyzed the influence of intra-arterial contrast injection on RVRA.
Main Results:
- 20% of essential hypertension patients exhibited an RVRR > 1.5, indicating overlap with renovascular hypertension.
- Intra-arterial contrast material showed variable and unpredictable effects on RVRA.
Conclusions:
- The RVRR demonstrates significant overlap between essential and renovascular hypertension, limiting its predictive value.
- Collecting renal venous blood for renin measurements immediately after angiography is not advisable due to unpredictable contrast material influence.
Abstract:
Despite recognized limitations, the renal vein renin ratio (RVRR) remains the most commonly used index of surgical curability in hypertensive patients with renal artery stenosis. It is generally held that a ratio exceeding 1.5 forecasts a favorable response to surgery. Measurement of this ratio in 40 patients with essential hypertension (no arteriographically demonstrated stenosis) showed 8 (20%) with RVRR over 1.5, confirming an overlap of this ratio between patients with essential and renovascular hypertension. Intra-arterial injection of contrast material influenced renal vein renin activity (RVRA) in some individuals, but we were unable to demonstrate significant alterations in the group as a whole. Since the influence of intra-arterial contrast material on RVRA is variable and unpredictable, it appears unwise to collect renal venous blood for renin measurements soon after angiography.