Clinical findings and hemodynamic changes associated with severe occlusive carotid artery disease

OBJECTIVE: The purpose of the study was to evaluate the ophthalmologic findings and to analyze the retrobulbar hemodynamics of patients with severe (greater than 70% stenosis) occlusive carotid artery disease (OCAD) by means of color Doppler imaging (CDI). DESIGN: A case-controlled study. PARTICIPANTS: Fifty-six consecutive patients with severe OCAD and an age- and sex-matched control group consisting of 56 healthy patients without OCAD were studied. INTERVENTION: All 112 patients underwent a complete ophthalmologic examination. Color Doppler imaging of both orbits was performed by one masked investigator. MAIN OUTCOME MEASURES: Peak systolic velocity, end diastolic velocity, and the resistive index of the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. The authors compared the hemodynamic parameters measured in patients with severe OCAD with those obtained in the control group. The hemodynamic parameters of patients with asymmetric OCAD (stenosis > 70% in one internal carotid artery and stenosis < 50% in the contralateral artery) were also compared. In an attempt to determine risk factors associated with the ocular ischemic syndrome (OIS), the authors compared patients with severe OCAD and OIS with patients with severe OCAD without OIS. RESULTS: Peak systolic and end diastolic velocities in the ophthalmic, central retinal, and temporal short posterior ciliary arteries were significantly lower in patients with severe OCAD (P < 0.01). The mean resistive indices in the central retinal and temporal short posterior ciliary arteries were higher in the group with severe OCAD (P < 0.01). Similar results were obtained in the analysis of 25 patients with asymmetric carotid stenosis. Younger age (P = 0.012), severe bilateral OCAD (P = 0.01), high-grade carotid stenosis (P = 0.013), and reversed ophthalmic artery flow (P = 0.038) were significant risk factors for OIS. CONCLUSIONS: Patients with severe OCAD show hemodynamic changes that suggest reduced retrobulbar blood flow. Patients with severe bilateral OCAD, high-grade carotid stenosis, and reversed ophthalmic artery flow may have a greater risk of developing OIS.     

Angioplasty and stenting of the carotid artery

Percutaneous endovascular techniques are well established procedures in the management of peripheral vascular disease and visceral arterial stenosis. They are now being adapted for use in the carotid artery as well. 8 patients with 9 extracranial carotid artery stenoses were successfully treated by percutaneous angioplasty, following which in 4 of them 5 stents were inserted. The stenotic lesions were situated in the proximal internal carotid artery and in its bifurcation and also in the common carotid artery. The indications for angioplasty in these patients were the same as for surgery. There were no major complications. 1 patient had transient hemiparesis lasting a few hours, and another had bradycardia following balloon dilation in the region of the carotid body. Percutaneous endovascular treatment of carotid artery stenosis is becoming a safe, feasible alternative to surgery.     

Elective carotid artery stenting in the presence of contralateral occlusion

Significant carotid stenosis in the presence of an occluded contralateral artery has a poor prognosis with medical therapy alone. Carotid cross clamping during surgical endarterectomy results in critical flow reductions in patients with inadequate collateral flow, and represents a significant risk for procedural strokes. Carotid stenting is being evaluated as an alternative to endarterectomy. We describe the immediate and late outcome of a series of 26 patients treated with carotid stenting in the presence of contralateral carotid occlusion. The mean age of the patients in this group was 65 +/- 9 years, 23 (89%) were men and 10 (39%) were symptomatic from the vessel treated. The procedural success of carotid stenting in this group of patients was 96%. The mean diameter stenosis was reduced from 76 +/- 15% to 2.8 +/- 5%. There was 1 (3.8%) minor stroke in a patient who developed air embolism during baseline angiography. At late follow-up there was no neurologic event in any patient at a mean of 16 +/- 9.5 months after the procedure. Thus, carotid stenting of lesions with contralateral occlusion can be performed successfully with a low incidence of procedural neurologic complications and late stroke.     

Elective stenting of carotid artery stenosis in patients with severe coronary artery disease

AIMS: To evaluate the feasibility and safety of elective carotid stent implantation in patients with carotid stenoses and concomitant coronary artery disease, as an alternative to combined carotid and coronary surgery. METHODS: We treated 50 patients with >70%, stenoses in 53 carotid arteries with balloon angioplasty followed by elective stent implantation. All patients had severe coronary artery disease, and/or mitral insufficiency, aortic stenosis, rhythm disorders or generalized arteriosclerosis. In three patients the opposite carotid artery was occluded; nine patients had bilateral stenoses of which two received stents bilaterally. RESULTS: Fifty-six successful stent implantations (42 Wallstents, eight BeStents, two AVE-Microstents, one Palmaz Schatz stent, three Sito stents) were performed, reducing the baseline percent stenosis from 78 +/- 18%, to 13 +/- 11%. Complications included three transient ischaemic attacks, one minor and one major stroke. Follow-up was available for 46 patients over a mean of 10 months. Three asymptomatic restenoses and one deformation of a BeStent occurred. CONCLUSION: Our preliminary results indicate that carotid artery stenting in patients with concomitant severe coronary artery disease is feasible, safe, and may be an alternative to combined carotid and coronary surgery.     

Predicting hemodynamic ischemia by transcranial Doppler monitoring during therapeutic balloon occlusion of the internal carotid artery

PURPOSE: Our objective was to evaluate the sensitivity of transcranial Doppler (TCD) sonographic monitoring during permanent balloon occlusion of the internal carotid artery (ICA) in predicting hemodynamic ischemia. METHODS: Thirty-two consecutive patients underwent controlled therapeutic balloon occlusion of the ICA. Selection criteria included assessment of the circle of Willis by compression angiography, clinical tolerance during a 20-minute test occlusion, and TCD monitoring of the ipsilateral middle cerebral artery. The mean blood flow velocity (MBFV) (n = 32) and pulsatility index (PI) (n = 28) were recorded. In 25 patients, MBFV changes upon motor stimulation were recorded before and after ICA occlusion. RESULTS: Twenty-eight (88%) of the patients had no complications. Three patients suffered delayed symptoms 30 minutes to 20 hours after balloon detachment. Two of these patients recovered spontaneously within 1 day, the other improved after extracranial/intracranial (EC/IC) bypass surgery. One patient, who did not tolerate the test occlusion, suffered a hemodynamic stroke despite EC/IC bypass before permanent balloon occlusion. No embolic complications occurred. The mean MBFV reduction was 20% (range, 0% to 55%); the mean PI reduction was 20% (range, 0% to 56%). No complications occurred in patients who had mild MBFV and PI reduction (30% or less, n = 21). All three patients with severe MBFV or PI reduction (> 50%) had neurologic symptoms. Among those with moderate MBFV or PI reduction (30% to 50%, n = 8), symptoms developed in only one patient who had moderate reduction of both MBFV (33%) and PI (38%). Motor vasoreactivity showed wide variation and was markedly reduced in two symptomatic patients. CONCLUSION: TCD monitoring reflects changes in cerebral hemodynamics after therapeutic balloon occlusion of the ICA. MBFV and PI reductions under 30% are highly predictive of clinical tolerance. A reduction of more than 50% may be a critical threshold for the occurrence of symptoms; in such cases, EC/IC bypass should be considered before proceeding with permanent balloon occlusion.     

Predictive value of carotid artery stump pressures during carotid endarterectomy

The ideal method of monitoring cerebral perfusion during carotid endarterectomy remains controversial. This article reviews many of the larger studies in the literature that have attempted to evaluate the usefulness of carotid artery stump pressure. Topics discussed include stump pressure alone, regional anesthesia, stump pressure and EEG, and stump pressures and transcranial Doppler ultrasonography.     

Comparison of hemodynamic cerebral ischemia and microembolic signals detected during carotid endarterectomy and carotid angioplasty

BACKGROUND AND PURPOSE: There has been concern about carotid percutaneous transluminal angioplasty (PTA) carrying a greater risk of cerebral ischemia than carotid endarterectomy. We set out to compare cerebral hemodynamics and microembolization during carotid PTA and CEA. METHODS: We used transcranial Doppler to monitor the middle cerebral artery of 28 patients undergoing carotid PTA (n = 14) or carotid endarterectomy (CEA) with a shunt (n = 14). Each period during which the internal carotid artery was occluded by PTA balloon or by clamp when the shunt was not in place was timed. Individual periods were summated to give a total occlusion time. Ischemic time was defined as the period for which mean middle cerebral artery velocity fell to a third or less of baseline. Microembolic signals were counted during each procedure. RESULTS: CEA resulted in significantly longer individual and total occlusion time than PTA (mean individual occlusion time, seconds), CEA, 168 +/- 51; PTA, 20 +/- 7; P < .001; mean total occlusion time; CEA, 337 +/- 70; PTA, 26 +/- 10; P < .001. Ischemic time was also significantly longer during CEA than during PTA (CEA, 165 +/- 40; PTA, 17 +/- 5; P = .001). There were significantly more microembolic signals during PTA than during CEA (mean number of microembolic signals during CEA, 52 +/- 64; during PTA, 202 +/- 119; P = .001). There was no correlation between any of the parameters measured and periprocedural stroke, which occurred in one patient in each group. CONCLUSION: PTA results in less hemodynamic ischemia but more cerebral microembolism than CEA. In this small series, however, it is not possible to comment on the relations between ischemic time, microembolism, and stroke.     

Severe occlusive carotid artery disease: hemodynamic assessment by MR perfusion imaging in symptomatic patients

BACKGROUND: The purpose of this study was to assess the capability of magnetic resonance imaging (MRI) and cytology and flow cytometric (FCM) deoxyribonucleic acid (DNA) analysis in fine-needle aspiration biopsy (FNAB)-derived materials for diagnosing malignancy of the parotid lesions and the efficacy of FCM analysis in FNAB. METHODS: Magnetic resonance imaging findings and FCM results (ploidy and S + G2 + M phases [S + G2M] fraction) and cytology in FNAB-derived materials in 26 patients with 26 parotid lesions (12 benign lesions, 14 malignancies) were assessed for predicting malignancy. Flow cytometric results in aspirates were compared with those in surgically resected tissues. RESULTS: When a single predictor was used, cytology (92% accuracy) was most accurate for malignancy, followed by ill-defined margin (88% accuracy) and aneuploidy (88% accuracy). The combination of FCM and cytology raised the rate of sufficient materials from 92% to 100% and accuracy from 92% to 96% compared with cytology alone. The same highest accuracy (96%) was obtained with the combination of the ill-defined margin or other findings such as cytology, aneuploidy, or a high (S + G2M) fraction (6% <). Deoxyribonucleic acid ploidy in the FNAB showed full agreement with that in the surgical specimens. Receiver operating characteristic curves showed that the diagnosis of malignancy with (S + G2M) fraction in FNAB was superior to that in surgical specimens, but no significant difference was noted. CONCLUSIONS: A combination of MRI findings, cytology, and FCM results is optimal for diagnosing malignancies of the parotid lesions, and FNAB may replace the surgical specimens in FCM analysis.     

The hemodynamic changes during the intraperitoneal hyperthermic perfusion under induced hypothermia

We investigated the whole body oxygen consumption (VO2) and the hemodynamic changes during the intraperitoneal hyperthermic perfusion (IPHP), which was coupled with induced hypothermia to prevent the cerebral disorder. IPHP was carried out for 90-120 min with 45-47 degrees C perfusate after the operation. We induced hypothermia using the surface cooling method and the infusion of triflupromazin. In no patient, the pulmonary artery temperature (PAT) rose above 40 degrees C. In the IPHP, there was a significant correlation between VO2 and PAT. If PAT reached 42 degrees C during the IPHP, VO2 would increase to 130-140% of the value at 37-38 degrees C. This rise is smaller than that during the total body hyperthermia (TBH), in which VO2 at 42 degrees C reached 130-190% of the value at 38 degrees C. Heart rate increased in proportion to the rising rate of body temperature. During the IPHP, PAT sometimes rose remarkably about 8 degrees C (from 32 degrees C to 40 degrees C) with a marked rise in heart rate. This rising rate of PAT is greater than that of TBH, in which PAT rose about 4-5 degrees C (from 37-38 degrees C to 42 degrees C). We consider that IPHP is not applicable to the patients with ischemic heart disease. During the rise of PAT, other circulatory parameters related to IPHP, changed in the same direction as those related to TBH. The rate of change of these parameters related to IPHP was smaller than that of the TBH, because during the IPHP the highest PAT was lower than that during TBH.     

Cerebral oximetry: a useful monitor during carotid artery surgery

Cerebral oximetry was evaluated as a monitor of oxygenation during carotid endarterectomy in 22 patients. The oximeter was a reliable continuous monitor, identifying changes in cerebral oxygenation during episodes of hypotension and after arterial occlusion. Changes in oxygenation correlated well with the surgical assessment of backbleeding after arterial clamping, but less well with other methods which are used to make a decision on insertion of an arterial shunt. There was no correlation between internal carotid artery stump pressure and change in cerebral oxygenation after application of the arterial cross clamp. However, cerebral oxygenation correlated weakly with the change in middle cerebral artery velocity as measured by transcranial Doppler ultrasonography (r = 0.49, p < 0.02).     

A cost comparison of balloon angioplasty and stenting versus endarterectomy for the treatment of carotid artery stenosis

PURPOSE: Percutaneous transluminal angioplasty with stenting (PTAS) of the carotid artery has been advocated as an alternative treatment for high-grade stenosis. Rationale for this approach includes less morbidity, shorter recovery, and lower cost when compared with carotid endarterectomy (CEA). METHODS: The clinical results and hospital charges of patients who underwent elective treatment for carotid stenosis were reviewed. During a concurrent 14-month period, 218 patients were admitted 229 times for 234 procedures for the treatment of 239 carotid bifurcation stenoses, 109 by PTAS and 130 by CEA. Hospital charges were reviewed for each hospitalization and were categorized according to radiology, operating room, cardiac catheterization laboratory, and all other hospital charges. RESULTS: The combined incidence of postprocedure strokes and deaths were: PTAS, eight strokes (7.7%) and one death (0.9%); CEA, two strokes (1.5%) and two deaths (1.5%). Total hospital charges per admission for the two groups were $30,140 for PTAS and $21,670 for CEA. The average postprocedure length of stay for PTAS was 2.9 days (median, 2 days) and for CEA was 3.1 days (median, 3 days). Cardiac catheterization laboratory charges for the PTAS group were $12,968, whereas the operating room charges for the CEA group were $4263. When hospitalizations that were extended by complications were excluded, the average total charges for the PTAS group (n = 84) dropped to $24,848 (mean length of stay, 1.9 days) and for the CEA group (n = 111) to $19,247 (mean length of stay, 2.6 days). CONCLUSIONS: After evaluating hospital charges, PTAS for the treatment of carotid stenosis cannot currently be justified on the basis of reduced costs alone. With future cost-containing measures, total hospital charges can be reduced in both groups.     

Intraabdominal hemorrhage during combined coronary artery bypass and carotid endarterectomy

Intraabdominal complications during cardiopulmonary bypass are extremely rare, with an incidence of less than 1% in multiple retrospective studies. These complications are associated with a high mortality, and their rapid diagnosis is critical to the outcome of the patient. We present a case of spontaneous intraabdominal hemorrhage after combined carotid endarterectomy and four-vessel coronary artery bypass grafting, which was diagnosed through a diaphragmatic window.     

Cerebral Ischemia during carotid endarterectomy with severe but reversible changes

Electroencephalographic monitoring of a patient during carotid endarterectomy demonstrated severe ipsilateral voltage suppression with preservation of rhythms when the common carotid artery was clamped. Because the atheromatous plaque extended almost to the base of the skull, it was impossible to insert a shunt. Occlusion time was 19 minutes. After carotid flow was re-established, there was a rapid recovery of voltage. The patient awoke with a profound hemiparesis, but this cleared almost completely within a week. The EEG changes indicated severe ischemia, but, though function was transiently impaired, there was no apparent cerebral necrosis. This case represents the most severe yet reversible episode of ischemia during carotid clamping reported to date. Preservation of EEG rhythms, even in the face of voltage suppression, may have been a favorable sign.     

Use of esmolol to prevent hemodynamic changes during intubation in general anesthesia

Regeneration-competent urodele Amphibia are highly resistant to spontaneous development of neoplasms, in comparison with other vertebrates which do not exhibit great regenerative power. This observation implies that at least one growth parameter of urodele cells might be subject to different developmental mechanisms than the cells of animals incapable of epimorphic regeneration. Therefore, keeping records concerning the incidence of tumors in urodeles and investigating those exceptional cases might prove invaluable in understanding the basic biological principles governing organ regeneration and carcinogenesis, and might therefore help in cancer therapy. The present report depicts a case of two spontaneous, dermal, melanoma-like tumors found in an adult newt Triturus cristatus. Both tumors were located in the pelvic region. Histological examinations and tumor transplantations were conducted. It was found that the tumors were melanomata. When allografted within the body cavity, their mass was progressively eliminated.     

Acute hemodynamic effects of lumbar sympathectomy

Lumbar sympathectomy increases total limb blood flow after aortofemoral bypass in a high percentage of cases. This was true in eleven of fourteen extremities (78.6 per cent) in our series even though no specific selection criteria for entry into the study, other than the need for aortofemoral bypass, were used: that is, patients were entered into the study irrespective of preoperative ankle/arm pressure indexes or results of hyperemia testing. Overall, flow rates after sympathectomy was added to aortofemoral bypass were 1.55 times greater than after aortofemoral bypass alone. This degree of augmentation of flow may be important, particularly in cases of limited outflow.