Related Experiment Videos
Screening for renovascular hypertension in a population with relatively low prevalence
K H Helin1, I Tikkanen, J E von Knorring
1Department of Internal Medicine, Helsinki University Central Hospital, Finland. karri.helin@huch.fi
Insights
Captopril renography (CRG) is a superior and cost-effective screening tool for renovascular hypertension compared to captopril challenge tests (CCT). Limiting CRG screening to specific patient groups enhances its cost-effectiveness for diagnosing renal artery stenosis.
Area of Science:
- Nephrology
- Cardiovascular Medicine
- Diagnostic Imaging
Background:
- Renovascular hypertension, caused by renal artery stenosis, is a significant contributor to secondary hypertension.
- Accurate and cost-effective diagnostic methods are crucial for timely intervention and management.
- Current screening methods like captopril challenge tests (CCT) and captopril renographies (CRG) have varying diagnostic accuracies and cost implications.
Purpose of the Study:
- To evaluate the diagnostic accuracy and cost-effectiveness of CCT and CRG for screening renovascular hypertension.
- To assess the efficacy of invasive treatments such as angioplasty and nephrectomy.
- To determine optimal patient selection criteria for cost-effective screening.
Main Methods:
- A cohort of 519 hypertensive patients were screened using CCT (n=405) and CRG (n=450).
- Abdominal angiography was performed on 84 patients with positive screening results or suspicious clinical presentation.
- Interventions included angioplasty and nephrectomy, with subsequent blood pressure and medication monitoring.
Main Results:
- CRG demonstrated higher diagnostic accuracy (sensitivity 100%, specificity 68%) compared to CCT (sensitivity 67%, specificity 39%) in patients undergoing angiography.
- Estimated specificity for the entire study population was 95% for CRG and 88% for CCT.
- Invasive treatment in 16 patients reduced systolic/diastolic blood pressure from 157/99 to 140/87 mmHg and antihypertensive drug use from 2.6 to 1.4.
- Screening with CRG and invasive treatment cost US$15,400 per successful outcome, versus US$10,400 for equivalent pharmacological treatment.
- Limiting CRG screening to specific high-prevalence groups (no renal parenchymal disease, younger age, or resistant hypertension) reduced the cost to US$7,300 per patient, missing only one elderly patient responsive to ACE inhibition.
Conclusions:
- CRG is diagnostically superior to CCT for screening renovascular hypertension.
- CRG screening is cost-effective when selectively applied to patients with specific clinical profiles.
- Targeted screening of patients with no obvious renal disease, younger onset hypertension, or resistance to two antihypertensive drugs optimizes resource utilization.
Objective:
To evaluate the accuracy and cost-efficacy of the diagnostic procedure and treatment for renovascular hypertension.
Setting And Patients:
A total of 519 patients referred to the university clinic for hypertension were screened for renovascular hypertension with 405 captopril challenge tests (CCT) and 450 captopril renographies (CRG).
Interventions:
Abdominal angiography was performed on 84 patients for positive screening. Fifteen patients underwent angiography for a sole suspicious clinical presentation. The angiography revealed 17 renal artery stenoses and five occlusions in 20 patients. Fifteen technically successful angioplasties and three nephrectomies were performed.
Results:
In the patients who underwent angiography, CCT had a specificity of 39% and a sensitivity of 67% for renovascular hypertension. CRG had a sensitivity of 100% and a specificity of 68%. In the whole study population, the estimated specificity of CCT was 88% and that of CRG 95%. Invasive treatment reduced systolic/diastolic blood pressure from 157/99 to 140/87 mmHg and the number of antihypertensive drugs used from 2.6 to 1.4 in 16 patients (mean age 49 years). Angiotensin converting enzyme (ACE) inhibition was effective in four elderly patients. Cost-efficacy analysis Screening with CRG and invasive treatment cost US$15400 per successful invasive treatment Equally effective pharmacological treatment would have cost US$10400. Limiting the screening with CRG to the 173 patients with no obvious renal parenchymal disease and with hypertension at a younger age (< or =30 years) or unresponsive to two antihypertensive drugs (diastolic blood pressure > 90 mmHg) would have yielded a prevalence of 12% and missed only one elderly patient who responded to ACE inhibition. The limited screening, along with invasive treatment, would have cost US$7300 per patient
Conclusions:
CRG is superior to CCT for screening of renovascular hypertension. Screening with CRG is cost-effective when limited to patients with no obvious renal parenchymal disease and with hypertension that does not respond to two antihypertensive drugs or is detected in patients no older than 30 years.