Screening for renovascular hypertension in a population with relatively low prevalence

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.     

Isolated pulmonary arteries involvement in a patient with Takayasu's arteritis

Pulmonary arteries involvement is well described in Takayasu's arteritis (TA), a condition which is mainly associated with involvement of the systemic arteries. We report a case of TA with documented isolated pulmonary arteries involvement. Symptoms were quite similar to those encountered in chronic thromboembolic disease. A pulmonary angiogram showed bilateral stenosis and occlusion of pulmonary arteries. Diagnosis of TA was suspected, and as such a complete aortogram was made but proved to be normal. Massive haemoptysis suddenly occurred, which resulted in death. Autopsy disclosed characteristic pathological lesions of TA in pulmonary arteries and confirmed the lack of involvement of the aorta and its branches. The frequency of such a clinical form could be underestimated, given the difficulties of diagnosis and features similar to those of chronic thromboembolic disease.     

Raised agalactosyl IgG and antimycobacterial humoral immunity in Takayasu's arteritis

OBJECTIVE: Takayasu's arteritis is an inflammatory occlusive disease of the aorta and its main branches of unknown etiology. Some suggested causes include inapparent infection with Mycobacterium tuberculosis, or autoimmunity evoked by this organism. We have therefore sought links with mycobacterial disease. METHODS: We assayed the % agalactosyl IgG, antibody to a tuberculosis-specific 38 kDa protein, and antibody to the mycobacterial 65 kDa heat shock protein (HSP), in patients with active or inactive Takayasu's arteritis, in whom the diagnosis of tuberculosis was excluded. The results were compared with findings in tuberculosis (positive controls), normal donors and patients with Wegener's granulomatosis. RESULTS: The % agalactosyl IgG in patients with active arteritis was in the range previously seen only in rheumatoid arthritis, Crohn's disease, and the mycobacterioses. Similarly, significantly raised antibody to the purified 38-kDa protein of M. tuberculosis, and to the 65-kDa HSP of M. leprae, was found in 78% of patients with Takayasu's arteritis, and the levels were higher in those with active disease. CONCLUSION: These results suggest that Takayasu's arteritis particularly clearly illustrates the occasional relationship between mycobacteria and diseases of superficially autoimmune pathogenesis.     

Pan-valvular annular calcification in Takayasu's arteritis: report of 3 cases

Takayasu's arteritis is a chronic inflammatory arteriopathy. It mainly affects the aortic arch and its main branches. The aortic valve annulus and coronary and pulmonary arteries are rarely affected. Mitral and tricuspid annular calcification were not reported previously. We identified mitral annular calcification by using transthoracic echocardiography in 3 patients with Takayasu's arteritis, in whom none had any of the reported causes of mitral annular calcification. Two of them had concomitant tricuspid and aortic annular calcification.     

Surgical treatment of renovascular hypertension

Two hundred sixty-four patients exhibiting renal artery occlusive disease underwent operation for renovascular hypertension between 1961 and 1977. Included were 27 pediatric patients. Fibrodysplastic disease affected 132 adults. Atherosclerotic lesions affected 51 patients with and 54 patients without clinically overt extrarenal arteriosclerotic cardiovascular disease. Ischemic kidney renin hypersecretion (renal: systemic index greater than 0.48), associated with suppressed contralateral kidney renin secretion (renal: systemic index approaching 0.0) predicted curability most reliably. Three hundred forty-eight operations were performed, of which 297 were primary and 51 were secondary procedures. Nephrectomy was initial therapy in 15 cases. Three operative deaths occurred among 51 patients manifesting overt extrarenal arteriosclerotic disease. No operative mortality was encountered among the other 213 patients. Surgical benefits were afforded 96% of pediatric patients and adults with fibrodysplastic disease, 91% of patients with focal renal arteriosclerosis, and 73% of those exhibiting overt extrarenal arteriosclerosis.     

A review of Takayasu's arteritis in children in Gauteng, South Africa

We have reviewed 31 patients with Takayasu's arteritis followed at two pediatric nephrology units in Gauteng, South Africa over a 15-year period. There were 25 black patients, 4 white, and 2 of mixed race. The mean age at diagnosis was 8.42+/-3.59 (range 2.4-14.5, median 8) years. The most common presenting sign was hypertension, followed by cardiac failure, bruits, and absent pulses. The Mantoux test was strongly positive in 27 patients (90%, control population 5%). Markers of activity included a raised erythrocyte sedimentation rate (23 patients) or Gallium single photon emission tomography (positive in 12 of 16 patients). Angiography revealed type II (abdominal aorta) and III (arch plus abdominal aorta) lesions to be most common (11 in each group). All patients received antituberculous therapy and most low-dose aspirin for its antithromboxane effect. Corticosteroids and further immunosuppression were used to control disease activity. We added total lymphoid irradiation (TLI) or cyclophosphamide. Twenty-six patients in all received further immunosuppression, with 13 patients in each group. Results were similar in the two groups, with similar pre- and posttherapy systolic blood pressures and creatinine clearances. Two patients in each group relapsed, 3 died in the TLI group and 2 in the cyclophosphamide group. Surgical intervention, usually in the quiescent phase, consisted mainly of renal autotransplantation. Because of the problems with TLI and 2 patients with papillary carcinoma of the thyroid with long-term follow-up, we no longer use TLI. We have shown that with active medical and surgical intervention the aggressive course of this disease in children can be modified.     

Captopril renal scintigraphy in renovascular hypertension

Renovascular disease is a common cause of secondary hypertension. Renal artery stenosis is present in up to one third of patients with clinical markers suggestive of renovascular hypertension, such as hypertension refractory to medical management, severe hypertension in a young patient and worsening of renal function after the use of an angiotensin-converting enzyme inhibitor. Early discovery of renal artery stenosis may allow amelioration or cure of the hypertension and halt progressive loss of renal function. Although renal arteriography remains the gold-standard aid to diagnosis and to planning surgical intervention, it is an invasive procedure that may cause deterioration of renal function. In the presence of renal artery stenosis, glomerular filtration is maintained by angiotensin. Administration of captopril in renal scintigraphy removes this compensatory mechanism and causes a temporary impairment of renal function in the affected kidney. Nuclear tracers can visualize this impairment, thus allowing assessment of the physiologic significance of a renal artery stenosis. The test can be done as a outpatient procedure.     

Management of the patient with renovascular hypertension

Renal artery stenosis, either fibromuscular or atheromatous, is probably the most common cause of secondary hypertension in man. Both of these diseases are active, ongoing processes that may be ameliorated but not cured by medical or surgical treatment. The clinical history and examination of the patient with hypertension may help differentiate renovascular hypertension from essential hypertension. The presence of a systolic-diastolic or continuous bruit is often an indicator of severe renal artery stenosis. Systemic hypertension is the physiologic consequence of significant renal artery stenosis. Knowledge of the basic concepts of the renin-angiotensin-aldosterone system, as has evolved from experimental models of renovascular hypertension, forms the basis for understanding the process of evaluation and treatment of such patients. The treatment of choice for the patient with severe hypertension and a functionally significant renovascular lesion is surgical--both in terms of successful treatment of hypertension and improved long-term prognosis. Diligent periodic reevaluation of these patients as well as those with less severe hypertension who are receiving medical treatment enables the physician to select the proper management that offers optimal control of patient blood pressure and avoids target-organ damage to the kidneys, central nervous system, or cardiovascular system.     

Increased plasma endothelin concentration in atherosclerotic renovascular hypertension

The aim was to investigate circulating levels of immunoreactive endothelin (ir-ET) in atherosclerotic renovascular hypertension (RVH), and to assess the role of the kidneys in its overall plasma concentration. We studied 16 hypertensive patients with renal artery stenosis evidenced by angiography and admitted to hospital for the diagnostic evaluation of RVH by renal vein plasma renin activity (PRA) determinations. The right femoral vein was catheterized to simultaneously measure PRA and ir-ET in both renal veins and inferior vena cava below the origin of the renal veins. RVH was present in 9 patients as indicated by diagnostic PRA renal vein ratios and the remaining 7 patients were considered to have essential hypertension (EH). Patients with RVH showed a marked increase in systemic plasma ir-ET concentration (10.3 +/- 0.9 pg/ml). Despite a significant increase of PRA in the vein of the ischemic (IK) versus the contralateral (CK) kidney in patients with RVH, no significant differences in ir-ET concentration were observed between both kidneys. These results indicate that patients with RVH have increased circulating levels of ir-ET. However, the higher systemic plasma ir-ET do not arise from the renal circulation, since plasma ir-ET is significantly higher in systemic circulation than in renal veins.     

The investigation of renovascular hypertension in children: the accuracy of radio-isotopes in detecting renovascular disease

Renovascular disease is an important cause of hypertension in children because it is potentially treatable by surgical or angioplasty techniques. The aim of this study was to assess the accuracy of radio-isotopes (DMSA, DTPA and MAG3) combined with the angiotensin converting enzyme inhibitor, captopril, in detecting children with renovascular hypertension. We retrospectively reviewed the ultrasound and pre- and post-captopril radionuclide studies (either DMSA and/or DPTA and/or MAG3) of children with sustained hypertension investigated at our institution. Renal angiography was used as the 'reference technique'. Thirty-nine children, over a period of 10 years, were evaluated: 17 (44%) children had renovascular disease that involved the proximal three divisions of the renal arteries, some of which were amenable to treatment. The overall sensitivity, specificity, positive predictive value and negative predictive value for detecting such renovascular disease, as assessed by changes between pre- and post-captopril radio-isotope studies, were disappointing at 59%, 68%, 59% and 68%, respectively. When considering only abnormalities in post-captopril studies, these indices were 82%, 41%, 52% and 75%, respectively. Three children with potentially treatable renovascular disease were not identified on the captopril studies. We conclude that renal angiography should remain the 'reference technique' in identifying children suspected of renovascular hypertension.     

A case report of Takayasu's arteritis with aortic pseudoaneurysm caused by aortic perforation

A 47-year-old man presented with hemoptysis. From around June 20, 1995, he had symptoms of a common cold, but hemoptysis suddenly occurred on July 1 and he was brought to hospital. The chest X-ray film showed pleural effusion and enlargement of the mediastinum. CT scans showed calcification of the aorta, with a pseudoaneurysm 8 cm in diameter anterior to the descending aorta. When thoracotomy was performed under partial extracorporeal circulation, the thoracic cavity was found to be filled with bloody hydrothorax and hematoma, and the lower lobe of the left lung was adherent to the descending aorta. After a longitudinal incision was made in the aorta, a perforation 7 mm in diameter was identified in the posterior wall, and this was assumed to be the cause of the pseudoaneurysm. This part of the aorta was replaced with a Woven Dacron graft. Takayasu's arteritis was diagnosed by histological examination of the resected specimen, and the changes in the aortic wall at the site of perforation were considered to be chronic. About 30% of patients with this disease have aortic ectasia, but only a few pseudoaneurysms have been reported. Since the pseudoaneurysm occurred in our patient after reduction in the dose of medication, the development of perforation was suggested to be related to this change. In the future, this patient will require careful follow up for anastomotic aneurysm.     

Detection of renovascular hypertension with angiotensin II blockade

Experiments with synthetic substance P incubated in whole blood show that apart from a moderate loss of activity immediately on exposure of the peptide to whole blood, it is inactivated slowly in this tissue, approximately 25% of control activity remaining after 30 min incubation. Incubation with plasma did not result in the degradation of substance P. The attenuation of substance P activity in blood may be due to enzymatic destruction within erythrocytes.