Renal artery stenosis towards the year 2000

Area of Science:

• Nephrology
• Cardiology
• Diagnostic Imaging

Background:

• Current functional diagnostic tests for renal artery stenosis, including captopril-renal scintigraphy and captopril-peripheral vein renin tests, exhibit moderate diagnostic accuracy (70% sensitivity, 90% specificity).
• Despite advancements like angiotensin converting enzyme (ACE) inhibitor challenges and new radiopharmaceuticals, scintigraphy's diagnostic value remains insufficient for widespread screening of hypertensive populations for renal artery stenosis.
• The efficacy of percutaneous transluminal renal angioplasty (PTRA) and stenting for renal artery stenosis is under scrutiny, prompting a re-evaluation of diagnostic and treatment strategies.

Purpose of the Study:

• To evaluate the effectiveness of functional diagnostic tests versus clinical criteria for selecting patients with potential renal artery stenosis for arteriography.
• To identify reliable clinical indicators for high-risk patients necessitating further investigation for renal artery stenosis.
• To assess the prevalence of renal artery stenosis in patients resistant to specific antihypertensive drug regimens.

Main Methods:

• Analysis of existing functional diagnostic tests (captopril-renal scintigraphy, captopril-peripheral vein renin test) for renal artery stenosis.
• Evaluation of clinical criteria, specifically blood pressure response to a standardized two-drug antihypertensive regimen, for identifying high-risk patients.
• Interim analysis of a prospective multicentre study in the Netherlands assessing renal artery stenosis prevalence in patients resistant to amlodipine/atenolol versus enalapril/hydrochlorothiazide combinations.
• Comparison of renal artery stenosis detection rates via intra-arterial digital subtraction angiography based on different drug resistance selection criteria.

Main Results:

• Functional diagnostic tests, while accurate, are not sufficiently effective for screening the broad hypertensive population for renal artery stenosis.
• Blood pressure resistance to a two-drug regimen emerged as a viable clinical criterion for identifying patients with a higher prevalence of renal artery stenosis (25% in amlodipine/atenolol resistant vs. 15% in enalapril/hydrochlorothiazide resistant).
• The choice of antihypertensive drug regimen did not significantly alter the overall detection rate of renal artery stenosis when drug resistance was used as the selection criterion for arteriography.

Conclusions:

• Clinical criteria, particularly resistance to antihypertensive drug therapy, offer a more practical approach to selecting patients for renal artery stenosis diagnosis compared to current functional tests.
• Future diagnostic advancements may favor non-invasive imaging techniques (e.g., contrast-enhanced color Doppler ultrasound, magnetic resonance angiography) for monitoring renal artery stenosis patients under medical management.
• The routine application of PTRA and stenting for renal artery stenosis may warrant reconsideration in favor of improved non-invasive diagnostics and conservative medical management.