lower extremity vascular surgery in the ischemic limb was best monitored by the activated clotting time kept in the range of 250 seconds, which correlates well with lower FPA levels reflecting significant inhibition of coagulation.

to be helpful in identifying external carotid lesions, which are quite frequent. The authors make a strong argument for use of this technique as a quality control measure to further improve results for carotid endarterectomy.

Paul E. Stanton, JY., ibID East Tennessee State Univenity Quillen-Dislmer College of Medicine

John J. Ricotta, MD Univenity of Rochester Medical Center

The application of operative ultrasound immediately

Lane RJ, Ackroyd N, Appleberg M, Graham J. World J following carotid endarterectomy

Surg 1987;11:593-7.

This article describes the authors’ experience with 175 carotid bifurcations scanned with intraoperative ultrasound imaging. The authors describe the abnormalities found with the ultrasound scan and relate this to immediate and long-term complication rates. They compared 175 patients who were scanned with 205 patients in whom a scan was not performed for various reasons. This is a retrospective review and not a prospective randomized study.

The authors found an incidence of abnormalities of 28% during intraoperative scanning. There were 17 major defects (I3%), most of which were in the external carotid artery. Most of the defects in the common carotid and internal carotid arteries were minor and did not require reoperation. Twelve of 17 patients (71%) with major de- fects had surgery again. When these defects were in the external carotid artery, the lesion was always confirmed and was successfully removed by additional endarterectomy of this segment. One suture line stenosis of the internal carotid artery was revised with a patch. Major defects that were not opened were often associated with a bruit at postoperative follow-up but neurologic deficit was rare in these patients.

Follow-up of patients with and without scanning over time did not show a reduction in morbidity, mortality, or recurrent stenosis in the group having imaging. Similarly there was no significant difference in morbidity in the scanned patients between those with the normal scan and those showing a deficit.

The primary value of intraoperative scanning seems to be as a quality control measure. In addition, significant lesions in the external carotid artery can be identified and repaired with minimal additional morbidity. Although no significant reduction in morbidity or recurrent stenosis has been associated with intraoperative scanning, this is prob- ably due to the low incidence of significant complications and the fact that the sample size was inadequate to detect significant difference.

This is a well-written article, which gives a good de- scription of intraoperative ultrasound imaging techniques. It also places appropriate emphasis on the technical aspects of carotid endarterectomy and the importance of quality control. Although it appears that intraoperative ultraso- nography may have little practical impact on morbidity for the individual practicing surgeon, this technique does seem

Beneficial eff2cts of combined colestipol-niacin on coronary atherosclerosis and coronary venous by-

Blankenhorn DH, Nessim SA, Johnson RL, et al. JAMA ass grafts

1987;257:3233-40.

The rationale for this study was the perceived lack of convincing evidence that reduction of blood cholesterol levels has direct beneficial effects on human atherosclerotic lesions. Previous studies have demonstrated that blood cholesterol levels influence the prevalence of atherosclerotic heart disease in humans, and several large clinical trials have indicated that morbidity and deaths from ischemic heart disease are reduced by therapy for reduction of cholesterol levels. However, such studies have not included angio- graphic observation of the subjects’ coronary arteries; therefore the mechanism underlying these benefits remains unproved. Previous human studies with angiographic ob- servation of arterial lesion change have not demonstrated significant treatment effects nor have they been controlled by randomization.

The Cholesterol-Lowering Atherosclerosis Study (CLAS) was a randomized, placebo-controlled, selectively blinded, angiographic trial designed to determine whether aggressive reduction of low-density lipoprotein (LDL) cholesterol with concomitant increase in high-density li- poprotein (HDL) cholesterol will reverse or retard the growth of atherosclerotic lesions. Nonsmoking normoten- sive men who had coronary bypass (N = 162) were ran- domzied to receive drug treatment (30 gm of colestipol plus 3 to I2 gm of niacin daily, titrated individually on the basis of blood cholesterol response) or to the placebo group. Dietary changes were made for patients in both groups. Before randomization, conventional selective cor- onary angiography was performed. A repeat angiogram was performed 2 years after randomization by the same angiographer, who was unaware of treatment assignment.

During the two years of treatment, drug therapy achieved a reduction of 26% in total plasma cholesterol, a reduction of 43% in LDL cholesterol, and a simultaneous elevation of 37% in HDL cholesterol. This resulted in significant reduction in the average number of lesions per subject that progressed compared with placebo subjects. In addition, new atheroma formation in native coronary arteries and incidence of new lesions or adverse changes in the bypass grafts themselves were significantly less in drug- treated subjects. Regression of atherosclerosis occurred in 16.2% of subjects treated with colestipol-niacin vs 2.4% of subjects given placebo.

The CLAS study is the first angiographic study pro-

Volume 8 Number 2 August 1988 Abmucts 209

viding clear evidence of benefit of lipid-lowering treatment effects on human atherosclerotic lesions. Additional later reports from the study are promised on the effects of the treatment protocol on atherosclerotic lesions in the femoral and carotid arteries, which were also examined with the use of the serial angiograms of the current study. David C. Brewster, MD Harvard Medical School

Hemodynamic and metabolic effects of cerebral revas- CLlIal-izati0n

Leblanc R, Tyler JL, Mohr G, et al. J Neurosurg 1987;66:529-35.

The substance of this report derives from a small but intensively studied group of six patients who ultimately had extracranial-intracranial bypass (superficial temporal artery-middle cerebral artery) for severe extracranial vas- cular disease. Five patients were operated on for ipsilateral transient ischemic episodes, whereas the sixth had a limited fixed deficit. One patient had a remote contralateral stroke and four others had contralateral mild focal deficits. An- giographic findings consisted of occlusion of the ipsilateral, internal carotid artery. in all six patients, three of whom also showed contralateral occlusion. Positron emission to- mography was obtained within 1 month of surgery and between 3 and 6 months postoperatively with oxygen I5-labeled carbon monoxide, oxygen, and carbon dioxide and fluorine 18-labeled fluorodeoxyglucose. Variables de- termined included cerebral blood flow, cerebral blood vol- ume, cerebral metabolic rates for both oxygen and glucose, and the oxygen extraction fraction in both hemispheres. These values were compared with those obtained from five elderly control subjects.

Postoperative angiography showed all six bypasses to be patent supplying a minimum of five branches of the middle cerebral artery. All patients remained asymptomatic with respect to transient ischemic episodes and no signif- icant surgical complications occurred. Of three patients tested for cognitive function, two demonstrated significant improvement. When compared with the elderly control group, these patients showed an increased cerebral blood volume and a diminished cerebral blood flow/volume ratio with diminished cerebral metabolic rate for oxygen in the symptomatic hemisphere. Patients with bilateral occlusions had similar changes noted in the asymptomatic hemisphere. Cerebral blood Aow was decreased in only one patient with bilateral carotid occlusion.

Although the authors emphasized that there were vari- ations in hemodynamic and metabolic variables after sur- gery, they believe the postoperative hemodynamic status was improved in both cerebral hemispheres in most pa- tients. This improvement was characterized by a decrease in cerebral blood volume bilaterally and an increase in the cerebral blood flow/volume ratio predominantly in the symptomatic hemisphere. The cerebral metabolic rate for oxygen was increased in only two patients. Although the

cerebral metabolic rate for glucose was measured, the sig- nificance of the results are uncertain because of the ques- tionable accuracy of glucose metabolism as determined with PET. That a reproducible effect on oxygen utilization after revascularization could not be demonstrated lends credence to skepticism regarding the effect of this proce- dure on cerebral oxygen metabolism.

Anthony D. Whittemore, MD Haward Medical School

Percutaneous transluminal balloon angioplasty of the aorta in patients with aortitis Khalilullah M, Tyagi S, Lochan R, et al. Circulation 1987;76:597-600.

This article is a preliminary report on the use of per- cutaneous transluminal balloon angioplasty for the treat- ment of aortitis. The authors describe this form of therapy in four young male patients. All of the patients had cardiac catheterization and aortography. Intraaortic pressure gra- dients were recorded across aortic stenoses.

After systemic heparinization, a No. 9F balloon cath- eter was used to dilate each stenotic segment. The balloon was inflated to 60% to 100% of the calculated “normal” aortic lumen but did not exceed three times the diameter of the stenotic segment. The stenosis was dilated for 15 to 20 seconds and repeated two to three times until the con- striction disappeared. After dilatation, pressure gradients were again calculated and a final aortogram was performed. Patients were observed in the intensive care unit for 24 hours and were treated empirically with aspirin (300 mg per day) and dipyridamole (300 mg per day) after dilata- tion. There were no angioplasty-related complications.

The blood pressure was measured in the follow-up period in the upper and lower extremities at rest and after exercise. At the end of 2 months, an aortogram was ob- tained and intraaortic pressures were again measured. The peak systolic gradient across the aortic stenosis decreased initially from 82.5 + 35.7 to 37.5 ? 1X.5 mm Hg and decreased even further to 13.8 -t 9.5 mm Hg when the intraaortic pressures were obtained 2 months later. Simi- larly, the diameter of the aortic lumen increased initially and showed a further increase when the aortogram was repeated. Follow-up ranged from 5 to 14 months (mean 8.5 t 4.1 months). Three of four patients remained nor- motensive without the need for antihypertensive medica- tion. Residual diastolic hypertension in the fourth patient was attributed to renal artery stenosis.

Although the experience with percutaneous translu- minal balloon angioplasty is sparse, this preliminary report offers hope for a treatment alternative for the serious prob- lem of aortitis. More experience with this technique, as well as longer patient follow-up, is needed before a defin- itive statement may be made regarding efficacy in the treat- ment of aortitis.

Kenneth E. Mchqwe, MD The University ofAtizona Health Sciences Center