X-Ray-Based Irradiation of Larvae and Pupae of the Navel Orangeworm (Lepidoptera: Pyralidae)

The suitability of adult male the navel orangeworm, Amyelois transitella (Walker) for Sterile Insect Technique (SIT) has been reported for both high energy gamma (>1 MeV) and low energy x-ray (90 keV) sterilization. However, research regarding sterilization of NOW larvae and pupae by gamma irradiation indicated nonsuitability due to high mortality. Here, NOW larvae and pupae were irradiated to doses up to 50 Gy with 90 keV x-rays, then paired with nonirradiated colony mates. Sterility of surviving insects was determined by the presence or absence of hatched neonates. While presence of offspring does not guarantee viability, the absence does guarantee sterility (as is appropriate for SIT) and was thus the measure used here. Early stage larvae experienced 77% mortality at a dose of 30 Gy, versus 20% for nonirradiated control. At 40 Gy, mortality reached 98%. Of surviving early stage larvae at 30 Gy, 29% of moth pairs produced offspring. For late stage larvae, no offspring were produced at 40 Gy, but mortality was 73%. For pupae, mortality reached 53% at 30 Gy with 13% still producing neonates, while mortality reached 98% at 40 Gy. These results are consistent with reported results for gamma irradiation of NOW larvae where sterility was observed somewhere between the 30 Gy and 60 Gy data points, but mortality was high. This further confirms the lack of suitability of NOW irradiated in the larval stage, whether by gamma or x-ray, and supports the hypothesis that x-ray and gamma treatments are biologically equivalent at equal doses.

Statistical Correlation of Liver Function Tests with Coagulation Factor Deficiencies in Laennec’s Cirrhosis

Hemorrhage is one of the most serious complications of chronic liver disease. Deficiency of plasma coagulation factors, thrombocytopenia, and increased vascular fragility have been reported in many patients with Laennec’s cirrhosis. Factors V, VII, IX, X and prothrombin were deficient in a majority of the 25 patients included in this study.

Six tests of liver function and seven of plasma coagulation factors were evaluated, using the method of statistical regression analysis. The intercorrelation of tests in each group was evaluated as well as the correlation between liver function tests and plasma coagulation factors. Fibrinogen deficiency was not felt to play a significant role in hemorrhagic diathesis in our cases.

The major volatile compound 2-phenylethanol from the biocontrol yeast, Pichia anomala, inhibits growth and expression of aflatoxin biosynthetic genes of Aspergillus flavus

Aspergillus flavus is a ubiquitous saprophyte that is able to produce the most potent natural carcinogenic compound known as aflatoxin B1 (AFB1). This toxin frequently contaminates crops including corn, cotton, peanuts, and tree nuts causing substantial economic loss worldwide. Consequently, more than 100 countries have strict regulations limiting AFB1 in foodstuffs and feedstuffs. Plants and microbes are able to produce volatile compounds that act as a defense mechanism against other organisms. Pichia anomala strain WRL-076 is a biocontrol yeast currently being tested to reduce AF contamination of tree nuts in California. We used the SPME-GC/MS analysis and identified the major volatile compound produced by this strain to be 2-phenylethanol (2-PE). It inhibited spore germination and AF production of A. flavus. Inhibition of AF formation by 2-PE was correlated with significant down regulation of clustering AF biosynthesis genes as evidenced by several to greater than 10,000-fold decrease in gene expression. In a time-course analysis we found that 2-PE also altered the expression patterns of chromatin modifying genes, MYST1, MYST2, MYST3, gcn5, hdaA and rpdA. The biocontrol capacity of P. anomala can be attributed to the production of 2-PE, which affects spore germination, growth, toxin production, and gene expression in A. flavus.

Ocular volume change per minute with ocular pneumoplethysmography

Ocular pneumoplethysmography was performed before and after 1,737 carotid endarterectomies, 82% of which were performed for carotid lesions of hemodynamic consequence. Preoperative ocular hypoperfusion without ischemia was associated with at least transient postoperative ocular hyperemia. A difference in ocular volume change per minute of 14.0%, female greater than male, was explained by sex differences in heart rate, brachial pulse pressure and eye size. These observations may have a direct application in the management of diabetic retinopathy with panretinal photocoagulation.

Extra-anatomic redo of MIDCAB and OPCAB: an early experience

BACKGROUND

Eighteen patients with unstable angina underwent repeat myocardial revascularization without cardiopulmonary bypass using saphenous vein grafts from either the left (13) or right (2) axillary arteries or the descending thoracic aorta (3). Patients' ages ranged from 53 to 85 years. Left ventricular ejection fractions ranged from 15% to 60%.

METHODS

In 14 patients, the heart was exposed through an anterior thoracotomy, a minimally invasive direct coronary artery bypass (MIDCAB) technique. In 3 patients a left posterolateral thoractomy (lateral MIDCAB) was performed. One patient underwent repeat sternotomy (off-pump coronary artery bypass: OPCAB). In MIDCAB and lateral MIDCAB patients, the "target" vessel was a coronary artery in 8 patients and a previously placed vein graft in the remaining 9 patients. One patient underwent repeat sternotomy, and 3 coronary arteries were bypassed with a complex vein graft attached to the left axillary artery. Two patients died of mesenteric ischemia on the 2nd and 7th postoperative day. The remainder of patients were discharged from the hospital free of angina. Early graft patency was demonstrated by noninvasive vascular laboratory testing and/or angiography in the 13 survivors in whom the axillary artery had been the site of the proximal anastomosis.

RESULTS

Follow-up ranged from 1 to 25 months. No other patients have died, and none have undergone additional surgical or catheter-based procedures. Three patients have developed recurrent angina, and in 4 patients the extra-anatomic bypass grafts have apparently become occluded.

CONCLUSION

Extra-anatomic, off-pump bypass from the axillary artery or descending thoracic aorta to one or more coronary arteries can be performed safely in seriously ill patients requiring a repeat bypass procedure. The early results, regarding relief of angina, are encouraging.

Outcome of severe brain injury: a multimodality neurophysiologic study

We screened all head-injured trauma patients admitted to Lehigh Valley Hospital during a 2-year period. From 725 screened patients, 69 patients in a coma on the second day after trauma were entered into this study. During the first week, these patients underwent electroencephalography (EEG), evoked potentials, ocular pneumoplethysmography, and transcranial Doppler (TCD) sonography. Clinical examinations were undertaken 2 and 7 days after trauma. Test results were correlated with functional clinical outcome at 6 months. In a multiple regression analysis, EEG was the major independent variable that significantly predicted 6-month outcome based on Glasgow Outcome Scale score. Transcranial Doppler sonography contributed a small additional component. Though EEG was the most significant predictive factor in this neurophysiological battery, it did not add significantly to the predictive power of Glasgow Coma Scale score determined at day 7. These findings suggest that in neurophysiologic testing in this type of patient is not useful in improving predictive outcome data.

Internal carotid artery redundancy is significantly associated with dissection

BACKGROUND AND PURPOSE

Redundant internal carotid arteries have been considered a risk factor in tonsillectomy, adenoidectomy, and surgical treatment of peritonsillar abscess and also a potentially treatable cause of stroke. However, an association between internal carotid artery redundancy and spontaneous dissection has not yet been clearly demonstrated.

METHODS

We reviewed, for spontaneous carotid artery dissection, records of all patients admitted to our institution during the period from 1986 through 1992 with the diagnosis of stroke or transient ischemic attack. We also reviewed 108 percutaneous cerebral arteriograms performed between September 1992 and December 1992 for presence of carotid artery redundancies.

RESULTS

Thirteen patients exhibited spontaneous dissection. Of these, 8 of 13 (62%) patients and 13 of 20 (65%) internal carotid arteries, viewed to the siphon, had significant redundancies, kinks, coils, or loops. Of 108 consecutive arteriograms of patients without dissection, in which 187 internal carotid arteries were viewed to the siphon, there were 20 (19%) patients and 22 (12%) of 187 vessels with significant redundancy. Five patients in the dissection group and 2 in the nondissection group had bilateral internal carotid artery redundancy (P = .0019 and P = .0001, respectively).

CONCLUSIONS

We found a significant correlation between internal carotid artery redundancy and dissection, particularly if redundancy is present bilaterally.

The impact of cardiac index on cerebral hemodynamics

BACKGROUND AND PURPOSE

Current noninvasive testing allows accurate assessment of cerebrovascular hemodynamics. The cardiovascular influence on the noninvasive assessment of cerebrovascular studies has not been defined. This study was designed to determine the effect of cardiac index (CI) on cerebral blood flow velocities, ocular pulse amplitude, ophthalmic systolic pressure, and ocular blood flow (OBF) as currently estimated by noninvasive laboratories.

METHODS

Based on a retrospective study of 181 patients, we prospectively evaluated 45 patients undergoing right heart catheterization for hemodynamic monitoring to correlate the relation between CI, transcranial Doppler sonography, and ocular pneumoplethysmography. Patients with hemodynamic instability, severe carotid stenoses, massive cerebral infarct, or sepsis were ineligible for the study. Simultaneous recordings of systemic blood pressure, ophthalmic systolic pressure, heart rate, ocular pulse amplitude, middle cerebral artery blood flow velocities, and cardiac output were obtained on all patients. OBF was calculated from the heart rate and ocular pulse amplitude.

RESULTS

The relation between OBF and CI is expressed by the equation CI = 2.36 + 0.61 x OBF (r = .47, P = .0010). The middle cerebral artery peak systolic velocities and CI had a correlation of .36 (P = .0181). The equation, derived from the linear relation between OBF and CI, was then validated on a sample of 15 patients. With the apparent linear relation between OBF and CI, we used the derived equation to predict CI from OBF. The OBF determination predicted CI within 30% in all patients and within 20% in 53.3% of the patients.

CONCLUSIONS

We demonstrated that OBF and middle cerebral artery systolic velocity decrease with diminishing CI. Our findings suggest that CI may be potentially estimated in selected patients by noninvasive assessment of OBF using ocular pneumoplethysmography.

Biomechanics of ocular pneumoplethysmography

A mathematical analysis of ocular pneumoplethysmography is presented, based on the physiological, anatomical, and biomechanical properties of the eye. Ocular pneumoplethysmography is a clinical procedure involving elevation of intraocular pressure, by application of a suction cup to the sclera, to a level that exceeds ophthalmic artery systolic pressure. As decay in intraocular pressure is allowed, return of retinal artery pulsations indicates ophthalmic artery systolic pressure. We obtain a quantitative relationship between increase in intraocular pressure and applied vacuum, and compare the theoretical predictions with experiments on rabbits in which a variable descending vacuum was applied to bilateral scleral eyecups. The bilateral intraocular pressures were simultaneously recorded from cannulae in the respective vitreous bodies, and the pressures at which return of ocular pulsations were observed were correlated with the scleral vacuums. Regression lines were calculated for three serial determinations in each animal, with two groups of animals distinguished by the inner diameter of the eyecups used. The theoretical results indicate that the relationship between intraocular pressure increase and applied vacuum is independent of Young's modulus, and depends primarily on the ratio of the diameter of the vacuum cup to the diameter of the eye.

The cerebral hyperperfusion syndrome: diagnostic value of ocular pneumoplethysmography

PURPOSE

There were two purposes to our study. The first was to characterize the ocular hyperperfusion associated with carotid endarterectomy. The second was to relate ocular hyperperfusion to the clinical presentation of cerebral hyperperfusion syndrome.

METHODS

This was a retrospective chart review of 2331 patients who underwent carotid endarterectomy at our institution between June 1978 and May 1991.

RESULTS

Twelve of these carotid endarterectomies were associated with ocular hyperperfusion on the side of operation. Clinical evidence of cerebral hyperperfusion syndrome was observed in five of these 12 procedures. In these five patients there were two associated fatal intracerebral hemorrhages and one permanent coma. In the latter three patients the contralateral internal carotid arteries were totally occluded.

CONCLUSION

Ocular hyperperfusion, as documented with ocular pneumoplethysmography, is useful in alerting the physician to the potential for development of the cerebral hyperperfusion syndrome.

Amplitude of the ocular pneumoplethysmography waveform is correlated with cardiac output

BACKGROUND AND PURPOSE

Ocular pulse amplitude, the amplitude of the ocular pneumoplethysmographic waveform, is altered in several ophthalmologic diseases that disturb ocular blood flow, implying that ocular pulse amplitude may provide an estimate of ocular blood flow. Because ocular blood flow currently cannot be quantified in humans, two experiments were undertaken to evaluate the association of ocular pulse amplitude with total body blood flow.

METHODS

In experiment 1, cardiac output was determined by cardiac catheterization in 181 patients who underwent OPG-Gee testing during the same hospitalization. In experiment 2, 110 instances of atrial arrhythmia captured on ocular pneumoplethysmographic tracings were evaluated for transient changes in heart rate (R-R ratio) associated with transient changes in ocular pulse amplitude (ocular pulse amplitude ratio).

RESULTS

In experiment 1, average ocular pulse amplitude in the two eyes (OPAAV) was significantly correlated with cardiac output/heart rate (r = 0.53; p < 0.0001) and cardiac index/heart rate (r = 0.43; p < 0.0001). In experiment 2, R-R ratio was significantly correlated with ocular pulse amplitude ratio (r = 0.85; p < 0.001).

CONCLUSIONS

These results show that ocular pulse amplitude, a physiological measurement obtained from the globe, is correlated with cardiac output. They imply that ocular pulse amplitude may provide a clinically useful estimate of at least the pulsatile component of ocular blood flow.

Risk factors for stroke after coronary artery bypass

To determine the prevalence of stroke after coronary artery bypass grafting and to evaluate risk factors, we reviewed the records of 1000 patients undergoing coronary bypass within a 1-year time period. Demographic and perioperative data were evaluated by chi 2 analysis. A history of diabetes, evidence of mural thrombus, positive oculopneumoplethysmography findings, increased age, aortic calcification, and postoperative arrhythmias all correlated with increased risk of permanent neurologic deficit for the patient undergoing coronary bypass. Risk factors were analyzed with stepwise logistic regression. A history of diabetes, presence of mural thrombi, and aortic calcification carried a higher probability that the patient would have a permanent neurologic deficit.

Abnormal ocular pneumoplethysmographic results in unilateral neovascular glaucoma

Little is known about the predictive value of ocular pneumoplethysmography in patients with ophthalmic disease. We evaluated eight patients with unilateral increased intraocular pressure due to neovascular glaucoma who did not have evidence of severe extracranial carotid stenosis by duplex scanning and continuous-wave Doppler ultrasound. The ophthalmic systolic pressure measured by ocular pneumoplethysmography was decreased in the affected eye of all eight patients, indicating that neovascular glaucoma may be a cause of abnormal ocular pneumoplethysmographic results. Patients with neovascular glaucoma tended to have larger interocular ophthalmic systolic pressure differences than other patients with false-positive ocular pneumoplethysmographic results by noninvasive criteria.

Collateral compensation of severe carotid stenosis

In 516 patients who had endarterectomies for unilateral severe carotid stenoses, arteriography demonstrated no contralateral severe stenoses or occlusions. Pre and postoperative ocular pneumoplethysmography (OPG-Gee) measured simultaneous bilateral ophthalmic systolic pressures (OSP). Immediately after each OPG test a brachial systolic pressure (BSP) was measured with a stethoscope, cuff and manometer. Bilateral ophthalmobrachial systolic pressure (OBSP) indices were calculated from the three pressures measured with the combined testing. Analysis of these OBSP data indicates that the severe stenoses were relatively well compensated in 314 of the 516 patients (61%) whereas there was limited collateral compensation in the remaining 202 patients (39%). The data also suggest that the latter group incurs a greater element of compensatory central hypertension, which is reversed by carotid endarterectomy.

Duplex ultrasound and ocular pneumoplethysmography concordance in detecting severe carotid stenosis

Concordance between two independent tests should serve to increase the accuracy of diagnosis. A combination of ocular pneumoplethysmography and duplex ultrasound, which uses high-resolution B-mode imaging plus spectral analysis, was used to evaluate 289 consecutive patients prior to biplane carotid angiography. Where there was concordance, the noninvasive tests predicted the presence or absence of hemodynamically severe carotid stenosis (75% or greater cross-sectional area reduction) with a sensitivity of 96.8%, a specificity of 95.9%, an accuracy of 96.2%, and positive and negative predictive values of 91.0% and 98.6%, respectively. Of the 538 study arteries, only four (0.74%) angiographically severe lesions escaped detection by both noninvasive tests. Sources of diagnostic error for both tests were defined. We believe that the combination of duplex ultrasound and ocular pneumoplethysmography significantly improves the overall assessment of carotid atherosclerosis.

Ocular pneumoplethysmography can help in the diagnosis of giant-cell arteritis

We compared the results of ocular pneumoplethysmography in nine patients who had a temporal artery biopsy (TAB) diagnostic of giant-cell arteritis with results of ocular pneumoplethysmography in nine patients with normal TAB results and 112 patients with anterior ischemic optic neuropathy or central retinal artery occlusion assumed to be nonarteritic. The mean +/- SD ocular pulse amplitude with ocular pneumoplethysmography was 3.9 +/- 1.8 mm in the group with abnormal TAB results and 10.6 +/- 4.0 mm in the group with normal TAB results. Every patient with abnormal TAB results had an average calculated ocular blood flow less than 0.60 mL/min, while only one patient with normal TAB results fell in this range. The average calculated ocular blood flow had a sensitivity of 100% and a specificity of 93.4% in the diagnosis of giant-cell arteritis, with a diagnostic accuracy of 93.9%. These results rival the diagnostic accuracy of the erythrocyte sedimentation rate and TAB results.

Ocular pneumoplethysmography after lens implantation

A series of letters in this journal discussed the safety of ocular pneumoplethysmography (OPG-Gee) in pseudophakic patients. In the interval since these letters, experience with OPG-Gee tests performed on 115 pseudophakic eyes demonstrated no ocular morbidity associated with these procedures.

Accessory nerve injury during carotid endarterectomy

Injury to the accessory nerve (cranial nerve XI) during carotid endarterectomy is rare; to date only three cases have been reported in the literature. Traction on the sternocleido-mastoid muscle was the proposed mechanism of injury in all three cases. Four cases of accessory nerve palsy occurred in 850 carotid endarterectomies performed between 1978 and 1986 at this institution, an incidence of 0.47%. All four patients had classic signs and symptoms of accessory nerve injury, which developed between 20 and 60 days after operation. The three most recent cases were examined specifically for accessory nerve injury in the immediate postoperative period and exhibited normal trapezius function. None had any other central nervous system dysfunction. Two of these patients regained full accessory nerve function and the most recent case is showing signs of reinnervation with conservative therapy. Isolated central nervous system and spontaneous accessory nerve palsies are exceptionally rare, and since any traction injury or transection should have been detected by postoperative examinations in three of four patients, we propose surgical scar formation as a mechanism of accessory nerve palsy after carotid endarterectomy. If such a palsy develops in the postoperative period, we recommend conservative therapy.

Reappraisal of ocular pneumoplethysmography after carotid endarterectomy

An initial report documented a 3-year experience (1978 through 1980) with ocular pneumoplethysmography (OPG-Gee) done in the recovery room after carotid endarterectomy. The present report analyzes a similar 4-year experience (1981 through 1984) on 864 carotid endarterectomies performed by 20 surgeons in which the results of OPG tests done in the recovery room suggested carotid endarterectomy thromboses in 33 of the 864 patients (3.8%). All patients underwent immediate reoperation, and thromboses were confirmed in 26 of the 33 patients (79%). In the seven patients without thromboses, findings at reoperation accounted for the abnormal physiology in six of the seven patients. Overall, in 32 of the 33 patients (97%) the recovery room OPG tests accurately reflected a source of hemodynamic compromise. The application of the special OPG-Gee criteria in this report will minimize needless reoperation after carotid endarterectomy.

Assessment of intra-aortic balloon pumping by ocular pneumoplethysmography

The ocular pneumoplethysmograph (OPG-Gee) has been used to screen for unsuspected carotid disease in candidates for cardiac operations. This article demonstrates that the validity of such screening is maintained, even if the patient is sustained by an intra-aortic balloon pump (IABP). An unexpected observation is the apparent reduction of ocular blood flow during IABP, which was reduced in this series of 56 patients by an average of 11.6 per cent.

Physiology of carotid endarterectomy with ocular pneumoplethysmography

Objective documentation of the quantitative physiologic changes associated with the repair of carotid lesions of hemodynamic consequence was obtained in 701 procedures by a comparison of pre- and postoperative ocular pneumoplethysmographic tests (OPG-Gee). The results of repair of severe stenoses depended on the status of the carotid artery opposite the repaired vessel. If the vessel opposite the carotid artery repaired was functionally patent, severely stenosed, or totally occluded, the ocular blood flow improvement on the side of repair was 16%, 27%, and 47%, respectively. Only in the latter group was improvement in ocular blood flow observed on the side opposite the carotid repair (13%). Ocular blood flow, the bulk of which (choroid) is not autoregulated, is a much more sensitive indicator of carotid lesions of hemodynamic consequence than is the autoregulated cerebral blood flow. OPG-Gee is presented as a simple noninvasive test that reliably and reproducibly assesses the quantitative physiologic changes associated with the repair of carotid lesions of hemodynamic consequence. The latter represent 84% of all carotid endarterectomies at this institution.

Ocular pneumoplethysmography

The development and clinical application of ocular pneumoplethysmography (OPG) has had its principal application in vascular surgery. However, many patients with suspected carotid arterial lesions have concomitant ocular disease. Vascular laboratories routinely consult with ophthalmologists regarding OPG application in such cases. This review has been prepared to familiarize ophthalmologists with all aspects of this procedure.

Review of a community hospital experience with carotid endarterectomy

Carotid endarterectomy was performed 743 times during 56 months in a community hospital by 24 surgeons. The mortality rate was 2.7% and permanent stroke occurred in 1.8%. Temporary postoperative neurologic deficit occurred in 3.5%. The frequency with which the surgeon performed the procedure did not appear significant in the incidence of postoperative morbidity and mortality.

Ocular pneumoplethysmography in cardiac pacing

Variations in ocular blood flow (OBF) reflect variations in cardiac stroke output very closely. The use of ocular pneumoplethysmography (OPG-Gee) for the measurement of OBF is a simple, noninvasive method of assessing the hemodynamics of ventricular versus atrioventricular sequential pacing.

The collateral hemispheric systolic pressure

Satisfactory calibrated BP tracings were obtained during 385 (85%) of 455 carotid endarterectomies. The pressures were measured from the distal common carotid arteries while the external carotid arteries were clamp occluded. Continuous recordings were made with and without proximal common carotid clamp occlusion. The two systolic pressures resulting in each patient were plotted as a single point on a graph, with the direct carotid systolic pressure on the abscissa and the back carotid systolic pressure on the ordinate. Formulae of the mean values in 101 of the 385 procedures, in which the opposite carotid systems contained severe stenoses or total occlusions, and the other 284 procedures, in which the opposite carotid systems had no notable lesions, demonstrate that the collateral hemispheric systolic pressure depends on the status of the opposite carotid artery and on the central BP. We derived formulae for these two groups of patients to demarcate the lowest collateral hemispheric systolic pressure adequate for hemispheric integrity during and following prolonged operative carotid occlusion or following permanent interruption of carotid blood flow as a result of thrombosis, ligation, or resection without graft replacement.

Ocular pneumoplethysmography in head-injured patients

Severe head injury is frequently associated with multiple trauma. In the comatose patient, endotracheal intubation and ventilator support are often required, if there is associated dyssynchronous spontaneous effort. The latter is managed with therapeutic (drug) paralysis. An elaborate life-support and monitoring system coupled with controlled paralysis limits the mobility of the patient for diagnostic procedures, and a continuing reevaluation of neurological status is difficult. Under these circumstances the ocular pneumoplethysmograph provides a simple rapid noninvasive assessment of ocular blood flow, and this reflects cerebral blood flow and alterations in brain compliance. Alterations in the therapeutic regimen can be based on these observations.

Ocular pneumoplethysmography in carotid-cavernous sinus fistulas

Pulsatile exophthalmos in association with carotid-cavernous sinus fistulas has been well defined anatomically, by angiography. This paper presents the physiological assessment of this entity, as measured with ocular pneumoplethysmography (OPG-Gee). The abnormal arteriovenous communication lowers resistance to arterial flow. This is characterized by a lowered ophthalmic systolic pressure and an increased ocular blood flow. The OPG readily documents the physiological result of therapeutic intervention.

Postendarterectomy carotid occlusion

In a prospective study of 300 carotid endarterectomies, ocular pneumoplethysmography (OPG-Gee) was performed in the recovery room after all procedures. Positive test findings, indicative of occlusion of the repaired vessels, were encountered after 16 (5%) of these procedures, and all 16 patients were completely asymptomatic. Serial test results, without angiographic confirmation, have remained positive in nine. Angiography confirmed the positive test results in three. Immediate reoperation, without angiography, confirmed the positive test findings in four, and normal flow was restored in all four cases. Success of carotid endarterectomy should not be measured by absence of symptoms. Objective documentation of persistent patency is essential. Present policy dictates that if recovery room test results are positive, the patient be returned to the operating room as soon as possible, with no delay for angiography.

Extracranial surgery for the low-flow-endangered brain

Angiography documented severe (greater than 75%, cross-sectional area) bilateral carotid stenotic or occlusive disease in 60 patients. One third of these patients were thought to have transient ischemic symptoms of low-flow rather than embolic etiology. Preangiographic ocular pneumoplethysmography (OPG-Gee) was obtained in all patients. Postoperative OPG studies were obtained in the 39 patients who underwent unilateral carotid surgery. In seven of the 39 patients who were operated on, bilateral procedures were performed; OPG studies were obtained after the second procedure also. Comparison of the preoperative and postoperative OPG studies provided convincing evidence that the establishment of major carotid inflow should be the primary objective in patients with severe bilateral carotid disease, and that distal extracranial-intracranial reconstruction should be reserved for patients failing to respond to augmented inflow because of deficient collateral vessels.