Stump pressure, electroencephalographic changes, and the contralateral carotid artery: another look at selective shunting.

BACKGROUND: Selective shunting during carotid endarterectomy is associated with the lowest operative stroke rate; therefore, patient selection for carotid shunting is critical. Electroencephalography (EEG) can detect ischemic brain cell dysfunction before irreversible injury. The carotid stump back pressure (CSP) has been inconsistent in determining the need for shunting, and contralateral carotid disease has had a variable impact. The purpose of this study was to evaluate CSP and operative EEG changes, and to determine the effect of contralateral carotid artery disease on determining the need for carotid shunting. METHODS: In 140 consecutive carotid procedures, operative EEG and CSP were monitored, and contralateral carotid disease was documented. The carotid stump pressure/mean arterial pressure index (CSP/MAP) was also calculated to determine if this was a better indicator of the need for shunting than the CSP alone. RESULTS: There was a 58% incidence of EEG changes when the CSP was < or = 25 mm Hg, 32% with a CSP of 26 to 50 mm Hg, and 4% with a CSP > 50 mm Hg. There was a 43% incidence of EEG changes and lower CSP among patients with a contralateral occlusion, both of which were significantly different from patients with a patent contralateral carotid artery. Three patients with CSP > 50 mm Hg had EEG changes, but none had a contralateral occlusion. Two patients had permanent neurologic deficits, and 2 had transient deficits. Excluding combined procedures, operative stroke rate was 0.8%. CONCLUSIONS: A CSP of < 50 mm Hg achieved a sensitivity of 89% in patients who developed ischemic EEG changes during carotid clamping, and a pressure > 50 mm Hg had a negative predictive value of 96%. However, a CSP of < 50 mm Hg had a positive predictive value of only 36%. Neither the addition of the status of the contralateral carotid artery or the calculation of the CSP/MAP improved the sensitivity of the CSP in determining the need for shunting. Operative EEG monitoring remains the most sensitive guide to carotid shunting in patients undergoing carotid endarterectomy under general anesthesia.

'Otorrhagia'. A symptom of posterior auricular artery aneurysm.

There are many reports regarding aneurysms of the external carotid artery and its branches, but the case presented in this paper, of an aneurysm of the posterior auricular artery, is a unique one.

Foregut revascularization via retrograde splenic artery perfusion after resection of a juxtaceliac mycotic aneurysm: complicated by pancreatic infarction because of cholesterol emboli.

A 66-year-old woman had development of a rapidly enlarging juxtaceliac mycotic aneurysm after therapy for lumbar osteomyelitis and a psoas abscess. The aneurysm was repaired through a thoracoabdominal approach with a Dacron aortic graft sewn end to end to the thoracic aorta and end to side to the infrarenal aorta. Perfusion was restored after oversewing the abdominal aorta above the superior mesenteric artery and oversewing the celiac trunk. After reperfusion the foregut remained critically ischemic despite a patent superior mesenteric artery. Foregut reperfusion was achieved by removing the spleen and anastomosing the distal splenic artery to the aortic graft. Recovery was complicated by infarction of the body of the pancreas because of cholesterol emboli, resulting in a large pleural effusion. After undergoing a subtotal pancreatectomy that preserved the splenic artery, the patient recovered without additional complications. During 8 years of follow-up, the patient has normoglycemia and has had no further infections complications. The distal splenic artery offers an excellent inflow for foregut revascularization; however, the pancreas is intolerant of atheromatous emboli.

Venous duplex imaging for the diagnosis of acute deep venous thrombosis.

Acute deep venous thrombosis (DVT) continues to be a common clinical problem requiring objective evaluation. Hemodynamic testing for acute DVT has been popular, but is inadequate for evaluating asymptomatic patients and symptomatic patients with isolated calf vein thrombi. Venous duplex imaging (VDI) has rapidly gained in popularity, and is generally accepted to be the noninvasive technique of choice for the evaluation of patients with acute DVT. Twenty-five reports evaluate gray-scale venous duplex imaging versus ascending phlebography in 2,781 symptomatic patients. The sensitivity for proximal DVT and calf DVT is 96 and 80%, respectively. Seven reports review the use of VDI for surveillance in 857 asymptomatic patients, with an overall sensitivity of 76% for proximal DVT and of 11% for isolated calf vein thrombosis. The results of color-flow duplex appear to be somewhat better; however, the numbers are considerably smaller. The results for identification of calf vein thrombosis in asymptomatic surveillance patients continue to be poor. VDI appears to be the best noninvasive diagnostic test for acute DVT, and may challenge ascending phlebography as the best diagnostic test for proximal DVT in symptomatic patients, although it will miss 20% of isolated calf DVT. VDI appears to be the best noninvasive screening technique for high-risk asymptomatic patients under surveillance; however, additional correlative studies with ascending phlebography are required. The addition of color Doppler images appears to have improved results, although these higher sensitivities may be the consequence of improved experience as much as the addition of color to the image.

Is transcranial Doppler a worthwhile addition to screening tests for cerebrovascular disease?

PURPOSE: Carotid duplex imaging has become the standard diagnostic evaluation for patients with suspected cerebrovascular disease. Transcranial Doppler ultrasonography expands the noninvasive diagnostic capabilities to the intracranial circulation. The purpose of this study was to evaluate the results of routine transcranial Doppler studies on patients referred for noninvasive cerebrovascular evaluation. METHODS: A total of 670 patients had routine transcranial Doppler examinations as part of their noninvasive cerebrovascular evaluation. Patients were categorized clinically and according to their severity of extracranial internal carotid artery stenosis (< 50%, 50% to 79%, 80% to 99%, occlusion). Transcranial Doppler examinations were classified as normal or abnormal (intracranial stenosis, collateral pathway, > 30% velocity difference normal or abnormal (intracranial stenosis, collateral pathway, > 30% velocity difference between sides, flow reversal, and velocities +/- SD from normal). RESULTS: Forty-eight percent of the patients were women, and 52% were men. The average age was 65.5 years. Fifty-four percent of the patients were white, 42% were black, 3% were Hispanic, and 1% were other. Forty-eight percent presented with hemispheric symptoms, 34% had no symptoms, and 18% had nonhemispheric symptoms. Forty-five percent (304 of 670) had an interpretable transcranial Doppler examination. The ability to insonate the basal cerebral arteries through the temporal bone was significantly reduced in women (p < 0.0001), black patients (p < 0.0001), and older patients (p < 0.0001). The results of forty-four percent of interpretable examinations were normal, 19% demonstrated side-to-side velocity differences, 13% showed collateral pathways, 11% showed velocities +/- 2 SD, 10% showed an intracranial stenosis, and 4% showed reversed flow pattern. Although 56% of the patients had notable findings, no patient had their diagnostic or therapeutic plan altered by the transcranial Doppler results. CONCLUSION: Less than 50% of the patients referred for first-time cerebrovascular examination had access for an interpretable transcranial Doppler examination. Though the number of positive findings is reasonably high, no material impact on diagnostic or treatment plans was seen in the patients in this series. These results indicate that selection criteria for examination of the intracranial arteries should be refined and that transcranial Doppler scanning should not be incorporated as part of the "routine" noninvasive cerebrovascular examination.

The piezoelectric pulse sensor device: a prospective evaluation.

The goal of this prospective study of the piezoelectric pulse sensor device was to determine its technical applications and its ability to detect lower extremity occlusive arterial disease. Ten extremities (five volunteers) were evaluated to assess the ability to place the sensor in the correct anatomic position on a foot without a palpable pulse during cuff occlusion so that pulsatile flow would be detected following cuff deflation; its sensitivity as an end-point detector for pulsatile perfusion; and whether there is a linear qualitative pulse wave response with increasing perfusion pressures. Forty extremities (20 patients) with suspected occlusive arterial disease were studied to evaluate its capability of detecting perfusion as compared with the presence of a palpable pulse, an audible Doppler signal, and a foot volume waveform. The placement of the sensor on 10 normal limbs with temporary arterial occlusion resulted in a recordable waveform following cuff deflation in 100% of the dorsalis pedis arteries and in 10% of the posterior tibial arteries. The piezoelectric pulse sensor was as sensitive for detecting pulsatile perfusion as an audible Doppler signal and demonstrated a linear change in the waveform's amplitude and shape with incremental changes in perfusion pressure. In the 40 extremities with ankle/brachial indices ranging from 0.00 to 1.35, there was uniform agreement between pulse volume and Pulse Check waveforms. The piezoelectric pulse sensor is a sensitive method for monitoring lower extremity arterial perfusion when supplied by the dorsalis pedis artery; however, it is inadequate for the posterior tibial artery.(ABSTRACT TRUNCATED AT 250 WORDS)