Background and Purpose We sought to evaluate the usefulness of limited abdominal aortography performed in conjunction with intra-arterial carotid digital subtraction arteriography (DSA) for identification of clinically unsuspected lesions.
Methods In a prospective study performed in the Department of Radiology after preliminary carotid duplex imaging, 401 consecutive bilateral carotid intra-arterial DSAs were performed for evaluation of cerebrovascular disease from June 1988 to November 1992.
Results We detected unilateral renal artery stenosis in 24 patients (6%), bilateral renal artery stenosis in 5, renal cell carcinoma in 1, renal artery aneurysm in 1, abdominal aortic aneurysm in 23 (5.7%), aortic ectasia in 16, and iliac aneurysm in 2.
Conclusions When single-plane digital abdominal aortography is performed in conjunction with carotid intra-arterial DSA, significant pathological lesions can be detected with little increase in morbidity and only modest increase in time and cost.
Since atherosclerosis is a generalized disease, patients with carotid artery stenosis may also have atherosclerotic involvement of the abdominal aorta and its visceral branches. Because screening tests for renal vascular hypertension such as intravenous pyelography and radioisotopic renography have a low positive predictive value, detection of renal artery stenosis by renal arteriography may be helpful for management of such patients. Similarly, clinical examination may miss abdominal aortic aneurysms in obese individuals.
Detection of unsuspected aortic and iliac aneurysms may permit elective repair. The purpose of this study was to evaluate the findings of limited abdominal aortography performed in conjunction with intra-arterial cervical carotid and cerebral digital subtraction angiography (DSA) for identification of the aforementioned unsuspected lesions.
Subjects and Methods
A prospective study was conducted in 401 consecutive patients (54% men, 46% women; age range, 46 to 86 years; mean age, 69.6 years) in whom abdominal aortograms had been performed concomitantly with intra-arterial cervical and cerebral DSA from June 1988 to November 1992. Patients with known or suspected abdominal aortic aneurysms or patients undergoing combined carotid and abdominal with lower extremity arteriography were excluded. The indications for intra-arterial cervical and cerebral DSA are listed in Table 1⇓. All patients underwent complete blood count, determination of blood urea nitrogen and serum creatinine levels, chest radiogram, and 12-lead electrocardiogram (Marquette) before intra-arterial DSA was performed. Preliminary carotid duplex imaging was performed in all patients.
After arch aortograms were completed, the catheter was withdrawn into the midabdominal area; between the L1-2 vertebrae, 20 mL of contrast (12 mL of sodium diatrizoate 60% plus 8 mL of normal saline) was injected at 750 psi at a rate of 15 mL/s during suspended patient respiration. The catheter was usually positioned at the level of the renal arteries. We did not use test injections for exact position of the catheter in the aorta to minimize the volume of contrast agent. Digital subtraction images were obtained at 3/s with the use of a Phillips Poly Diagnostic UV with an ADAC computer, model 2123 DTV 4112. Images were immediately reviewed. On rare occasions a repeat study was performed because of suboptimal catheterization or patient motion. This entire sequence took less than 3 minutes. Our typical study included 2 arch angiograms, 1 abdominal aortogram, and 6 selective cervical, carotid, and cerebral injections. Then 130 mL of contrast mixed with saline was filled in the syringe with the use of a Medrad (Mark IV) power injector (80 mL of contrast mixed with 50 mL of saline). We used 60 mL of contrast mixed with saline for two arch injections and 8 mL of contrast mixed with saline for each carotid and cerebral injection.
Patients found to have aortic aneurysm, iliac aneurysm, aortic ectasia, or renal cell carcinoma underwent further diagnostic ultrasound and CT of the abdomen.
Twenty-three abdominal aortic aneurysms were detected in our total study group (Figs 1⇓ and 2⇓). The size of these aneurysms ranged from 3.0 to 7.0 cm in transverse diameter (Table 2⇓). Aneurysm was defined as a greater than 50% increase in expected diameter, and aortic ectasia was defined as a less than 50% increase in transverse diameter. The remaining findings of abdominal aortography are listed in Table 3⇓.
Of 25 patients (6.2%) with aortic and iliac aneurysms, 21 were men and 4 were women. Eight patients (abdominal aortic aneurysms in 6; iliac aneurysms in 2) underwent aneurysm resection without additional conventional aortography.
Renal artery stenosis was diagnosed in 29 patients (unilateral in 24; bilateral in 5). In 10 patients the origins of renal arteries could not be accurately defined because of motion artifact and overlying gas. In 7 patients hypertension could not be controlled with medical management. Five patients underwent percutaneous renal artery balloon angioplasty, and 2 patients underwent renal artery bypass.
The patient with left subclavian artery occlusion was found to have renal cell carcinoma (Fig 3⇓) and underwent nephrectomy. Renal artery aneurysm had been diagnosed in an elderly man 4 years earlier; he is being followed up by yearly CT of the abdomen (Fig 4⇓).
One patient developed transient ischemic attack (transient weakness of the left side of the body), from which the patient recovered in a few minutes. Three patients had moderately sized hematomas in the groin without any evidence of pseudoaneurysm of the femoral artery; the hematomas resolved in the ensuing 2 to 3 weeks. There was no incidence of contrast media–induced acute renal failure.
The prevalence of abdominal aortic aneurysm is estimated to be 0.4% to 5.4% in older men, and the incidence appears to be increasing as a result of increasing life expectancy.1 2 Rupture of abdominal aortic aneurysm is responsible for 1.2% of the deaths of men and 0.6% of the deaths of women aged older than 65 years in the United States.3 Palpation of the abdomen and ultrasonography are useful screening tests; however, CT scanning and MRI are too expensive to be used as screening modalities. Because of the luminal clot lining the aneurysm, aortic aneurysm usually appears much smaller than its actual size by aortography; however, aortography is helpful in planning treatment. Carty et al4 diagnosed 11 infrarenal aortic aneurysms (8.4%) by limited ultrasound examination of the abdominal aorta in 131 patients prospectively referred for carotid duplex evaluation. These authors conducted a rapid survey of the abdominal aorta with a limited number of images. Recently a 20% incidence of aortic aneurysm was reported in patients with carotid stenosis greater than 30% as measured by duplex ultrasound.5 However, the authors defined aortic aneurysm as focal dilatation of the aorta greater than 2.5 cm, which is a liberal interpretation of the definition of aortic aneurysm. Prior studies have shown the prevalence of abdominal aortic aneurysms to be 5% to 10% in a series of older patients (aged 65 to 74 years) with hypertension, coronary artery disease, and peripheral vascular disease.6 7 8 9
In the present study of 401 patients with carotid artery stenosis, the incidence of abdominal aortic aneurysms was 5.7%. In addition to 23 confirmed aortic aneurysms in the present series, aortic ectasia was detected in 16 patients at the time of initial aortography. Three patients with aortic ectasia had progressive enlargement of the aorta to more than 5.0 cm in transverse diameter during the follow-up period (duration of the present study) and underwent aortic aneurysmectomy, which emphasizes the importance of diagnosing patients with aortic ectasia. A wide variation in the growth rate of small abdominal aortic aneurysms has been reported. Nevitt et al10 documented the growth rate of small abdominal aortic aneurysms to be 0.22 cm/y. However, Bernstein et al11 reported a mean growth rate of 0.4 cm/y in 49 patients with abdominal aortic aneurysms.
Frame et al12 found that a single screening test for abdominal aortic aneurysm in men aged 60 to 80 years by either ultrasound or abdominal palpation might be considered cost-effective although of modest benefit. However, repeated screening is not cost-effective. These authors found that screening for abdominal aortic aneurysm can be made to look very attractive or harmful, depending on the data used for screening. They concluded from their study that routine screening becomes more cost-effective if it is targeted to a population with a higher prevalence of abdominal aortic aneurysm, such as men with known coronary or peripheral vascular disease. Lederle et al13 recommended that persons older than 50 years undergo careful abdominal palpation aimed at detecting abdominal aortic aneurysm as part of a periodic health examination; they also recommended that obese older men (aged 60 to 75 years) at high risk for abdominal aortic aneurysm have at least one screening with abdominal ultrasound regardless of the findings on physical examination. However, Beede et al14 concluded that abdominal palpation aimed at detecting abdominal aortic aneurysm as part of a periodic health examination will lead to high false-positive results, and therefore screening for abdominal aortic aneurysm by ultrasound examination should not be based solely on the results of abdominal palpation.
In our study no patient was aware of the presence of aortic aneurysm, and therefore abdominal palpation did not detect aortic aneurysm in a single patient. We cannot confirm the validity of this finding because many patients were initially examined by a variety of primary care physicians and specialists. The sensitivity of physical examination in detecting abdominal aortic aneurysm is estimated to be from 23% to 96%,12 with surgical measurement or abdominal ultrasound as the “gold standard.”
The incidence of unilateral renal artery stenosis was 6% and that of bilateral renal artery stenosis was 1.2% in the present series. Intra-arterial DSA is adequate for identifying and quantifying significant main renal artery stenosis (≥50% stenosis).15 Seven patients in the present series underwent renal artery revascularization without undergoing further conventional renal arteriography. The patient with incidentally diagnosed renal cell carcinoma underwent left nephrectomy 30 months ago and has remained free from recurrence of metastatic disease. Honkala and Konturri16 reviewed 66 cases of renal cell carcinoma incidentally detected at the time of intravenous urography, angiography, ultrasound, or CT and reported better results than in cases in which diagnosis was suspected because of earlier diagnosis and earlier stage of the tumors at that time.
Additional charges for abdominal aortography as performed in the present study were $95 higher than the cost of ultrasonography of the abdominal aorta at our institution. In our opinion, although unproven, morbidity was not increased with the use of single-plane abdominal aortography, and in light of the minimal change in cost, the added detail gained by aortography justifies its use.
Ultrasound of the abdominal aorta is more accurate in diagnosing the exact size of aortic aneurysm than aortography. Since carotid aortography is scheduled by the primary care physician in many instances without initial consultation with neurologists or vascular surgeons, additional films of the abdominal aorta during carotid angiography will be helpful in diagnosing unsuspected aortic and iliac aneurysms. Iliac aneurysms are difficult to diagnose by ultrasound. Compared with ruptured aortic aneurysms, ruptured iliac aneurysms are associated with relatively higher mortality.
This study has detected a group of patients at high risk for the presence of abdominal aortic or iliac aneurysms and renal artery disease. Diagnosis of unsuspected aortic and iliac aneurysms by digital abdominal aortography and surgical repairs in appropriately selected patients can help to reduce morbidity and mortality from ruptured aortic aneurysms. Digital abdominal aortography can also be helpful in the diagnosis of rare pathological lesions such as renal cell carcinoma and renal artery aneurysm.
- Received January 9, 1995.
- Revision received April 18, 1995.
- Accepted April 18, 1995.
- Copyright © 1995 by American Heart Association
Vital Statistics of the United States, 1974. Washington, DC: US Dept of Health, Education, and Welfare; 1974. Publication PMS 79-1101 (Mortality, Vol 2, PRA).
Karanjia PN, Madden KP, Lobner S. Coexistence of abdominal aortic aneurysm in patients with carotid stenosis. Stroke. 1994;25:627-630.
Collin J, Araujo L, Walton T, Lindsell D. Oxford screening programme for abdominal aortic aneurysms in men aged 65-74 years. Lancet. 1988;148:753-756.
Lederle FA, Walker J, Reinke D. Selective screening for abdominal aortic aneurysms with physical examination and ultrasound. Arch Intern Med. 1988;148:753-756.