Varying impact of common carotid artery digital compression and internal carotid artery balloon test occlusion on cerebral hemodynamics

BACKGROUND: The purpose of this study was to compare the cerebral hemodynamic changes brought about by common carotid artery (CCA) digital compression and angiographic internal carotid artery (ICA) balloon occlusion. METHODS: Bilateral transcranial Doppler ultrasonographic monitoring of the middle cerebral artery blood velocity (VMCA) was performed in 12 subjects with neck neoplasms or traumatic carotid-cavernous fistulas. The MCA pulsatility index (PIMCA) and hemodynamic tension (Uhem MCA) were calculated. RESULTS: Common carotid artery compression provoked the largest drop in ipsilateral VMCA, PIMCA, and Uhem MCA. Common carotid artery compression caused a steal of blood from the intra- to the extracranial circulation, with the discrepancy in hemodynamic findings between CCA and ICA test occlusions being dependent on the quantity of reversed ipsilateral ICA blood flow. CONCLUSION: If the carotid artery is to be sacrificed, permanent ICA closure is the procedure of choice with respect to the occurrence of cerebral ischemic lesions in patients with neck neoplasms and ICA flow reversal during CCA compression.     

Operative treatment of carotid artery occlusion. A follow-up study

The action of ethanol on compound action potential, refractory periods and chronaxia are analyzed in 28 isolated sciatic nerves of toads. 85 mM ethanol increases the compound action potential and decreases the refractory periods. 342 and 513 mM ehtanol decrease the compound action potential and increase the absolute and relative refractory periods. These biphasic effects are discussed in relation with changes in Na+ and K+ permeabilities and to the greater sensitivity of thin fibers to the chemicals.     

Surgical treatment of internal carotid and posterior communicating artery aneurysms

Saccular aneurysms of the subarachnoid segment of the internal carotid artery (ICA) are very common. Although some of the aneurysms arising from the subarachnoid ICA have earned the reputation of easy to treat surgically, aneurysms in this region may be complex and quite difficult to repair. Even a simple aneurysm associated with the posterior communicating artery may harbor surprises for the unwary or inexperienced surgeon. This article details the pertinent anatomy of the subarachnoid internal carotid artery and associated saccular aneurysms, provides a guide to their diagnosis and surgical treatment, and briefly reviews some of the published surgical results. Pitfalls and technique tips are highlighted.     

Surgical treatment of partial extraluminal occlusion of first part of vertebral artery

This report presents the clinical concept of hindbrain ischemia due to partial extraluminal occlusion of a segment of the first part of the vertebral artery, and submits a definite method of surgical treatment. Thirty one patients with vertebral artery insufficiency are presented who had operations with striking post-operative symptomatic improvement. Operative selection of patients is dependent on aortic arch angiography with visualization of the neck vessels. There was no mortality and no significant morbidity in this series.     

Endovascular treatment of carotid artery occlusion in progressive stroke syndromes: technical note

OBJECTIVE AND IMPORTANCE: We describe two patients, with progressing neurological deficits, who showed improvement after revascularization of their carotid arteries using stents. CLINICAL PRESENTATION: One patient presented clinically with the symptoms of a middle cerebral artery territory stroke. Angiography demonstrated total occlusion of the right internal carotid artery (ICA), with evidence of clot from the origin of the ICA to the middle cerebral artery trifurcation. The second patient presented with bilateral ICA occlusions and evidence of a progressing left hemispheric deficit; she was receiving therapeutic levels of heparin at the time of deterioration of her condition. INTERVENTION: Thrombolysis and stenting successfully recanalized the occluded vessels, and the deficits of the first patient were reversed. With the second patient, a dissected carotid loop was encountered. Straightening of the loop with a wire and stenting of the carotid artery using two stents allowed revascularization of the left hemisphere and resolution of most of the deficits of this patient. CONCLUSION: This report demonstrates the technical feasibility of placing stents in high-risk patients with carotid artery occlusions from either dissection or atherosclerosis. Both patients sustained much smaller infarctions than would have been expected if the carotid artery territory had been infarcted. We report on the technical feasibility of reopening acutely closed ICAs by using endovascular methods.     

Surgical correction of the kinked carotid artery

The hemodynamic significance of the kinked internal carotid artery and cerebrovascular insufficiency are demonstrated. Several procedures have been devised to correct a carotid kink, but these involve resection or excision of the internal, external or common carotid artery. We currently prefer a reimplantation technique whereby preservation of the external carotid is maintained, resection of the internal carotid artery is avoided and, when necessary, endarterectomy may be safely employed.     

Cerebral haemodynamics in internal carotid artery trial occlusion

The purpose of this study was to analyse the cerebral haemodynamic changes brought about by trial occlusion of the internal carotid artery (ICA). Sixteen patients with surgically inaccessible cerebral aneurysms, carotid cavernous fistulas or neck neoplasms were monitored with transcranial Doppler ultrasonography (TCD) during 90-120 s angiographic ICA balloon occlusion or ICA closure with a Selverstone clamp. The blood velocity (V) was registered continuously in both middle cerebral arteries (MCA) while the pulsatility index (PIMCA) and haemodynamic tension (Uhem MCA) were calculated. ICA closure led to an instantaneous drop in the ipsilateral VMCA, PIMCA and Uhem MCA. The VMCA thereafter increased gradually until reaching a stable level. The subjects were grouped into those with initial drops in VMCA to > or = 60% of pre-occlusion value (group 1) and those that fell to < 60% (group 2), respectively. In group 1 autoregulatory mechanisms made the PIMCA decline further, while the Uhem MCA remained unaltered during ICA closure. In group 2, however, the PIMCA did not change further, while the Uhem MCA increased slightly. The cerebral haemodynamic features during ICA test occlusion were thus essentially different in the two groups. On re-opening the ICA, there was an overshoot in VMCA and Uhem MCA. Contralaterally, the VMCA was increased during ICA occlusion. Seven of the patients later had their ICA closed permanently. While none of five group 1 patients developed haemodynamic complications, two group 2 individuals experienced haemodynamic stroke. Assuming ICA sacrifice is feasible when test occlusion results in an ipsilateral initial reduction in VMCA to > or = 60% of pre-occlusion value, the corresponding limit for the Uhem MCA is > or = 40%. In the pre-operative evaluation of the haemodynamic risk related to ICA loss, TCD emerges as a reliable method. It also seems to allow for the reduction of test occlusion time to 90-120 s.     

Endovascular treatment of acute thrombotic occlusion of the cervical internal carotid artery associated with embolic occlusion of the middle cerebral artery: case report

A 68-year-old man with acute, total thrombotic occlusion of the right cervical internal carotid artery, associated with embolic occlusion of the ipsilateral middle cerebral artery, was treated by the endovascular approach, i.e., intra-arterial fibrinolysis and balloon angioplasty. Endovascular treatment for a totally occluded internal carotid artery is indicated in the very early stage where there is no thrombus or a short thrombus that can be evacuated. Fibrinolysis of the associated embolus in the middle cerebral artery, if any, can be done in the same session, enabling an early restoration of the blood flow.     

Surgical management of the totally occluded carotid artery

Surgical revascularization of the completely occluded carotid artery was evaluated in 19 symptomatic patients who had recurrent episodes of amaurosis fugax or transient hemiparesis. Nine had complete internal carotid occlusion on arteriography and 10 had severe stenosis which had progressed to total occlusion by the time of surgical exploration. At operation irreparable fibrotic changes were observed in four patients, but in 15 a pattern of proximal focal obstruction with relatively healthy distal internal carotid vessels was observed. Thromboendarterectomy produced good back-bleeding in most of these and resulted in improved carotid flow after operation. Seventeen of 19 patients were relieved of symptoms. Two patients continued to have symptoms, but less frequently. There were no deaths after operation. Follow-up from 3 to 36 months showed no change from immediate postoperative results. This study suggests that carotid artery exploration and thromboendarterectomy should be considered when transient ischemic episodes are present despite complete internal carotid artery occlusion.     

Abnormal origin of the vertebral artery from the common carotid artery

An abnormal origin of the vertebral artery from the common carotid artery (VA-CC) may occur on the right or left side with different embryonic mechanisms. We describe a patient with a double developmental anomaly, a right VA-CC and a right aortic arch. The rotation of the aortic arch caused a "twist" of the embryonic mechanisms of VA-CC and misdirected the differential diagnosis of the embryonic mechanisms at first glance. We discuss the pivotal points in differentiating the embryonic mechanisms of VA-CC.     

Complex structure of the common carotid artery of sheep

The aim of this study was to investigate the pattern of both neovascularization and reinnervation, and the relationship between the two processes, in keratodermal grafts, using confocal laser scanning microscopy, at different time points during the healing process. Keratodermal grafts were prepared in pigs by combining autologous dermis with cultured autologous keratinocytes. Immunohistochemistry was carried out on thick cryostat sections (100-150 microns), using antisera to the endothelial marker von Willebrand factor (vWf) and the pan-neuronal marker protein gene product 9.5 (PGP9.5). The results suggest that the neovascularization and reinnervation in the cultured keratodermal graft is almost complete at 6 weeks. Neovascularization precedes innervation, reaching the surface covered by the keratinocytes at 2 weeks, initially with a linear vascular pattern. From 3 weeks, there is a gradual arborization of the vessels to form a typical vascular plexus. The process of reinnervation is similar in pattern to that of neovascularization, although slower in developing a full network of fibres. In conclusion, the use of confocal microscopy allows the precise definition of complex patterns of neovascularization and nerve growth, which are not fully apparent when using conventional microscopy. Because angiogenesis occurs first, it probably plays a leading role in the survival of keratodermal grafts during wound healing. Indeed, new blood vessels form a pathway for the subsequent innervation process, and quickly reach the epidermal layer which, in turn, may play a key role in the tropism of both blood vessels and nerves.     

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.     

Anomalous thymic branch of the right common carotid artery

A previously unreported anomalous thymic artery that branched from the anterior aspect of right common carotid artery approximately 1 cm above bifurcation of the brachiocephalic artery was found during routine dissection. It traveled inferiorly through a plexus of inferior thyroid veins for 6 cm in front of the brachiocephalic artery and crossed the anterior surface of the trachea where it divided into two branches that supplied the right and left lobes of the thymus. The development and blood supply of the thymus and their clinical anatomy are reviewed.     

Bilateral optic disk pallor after unilateral internal carotid artery occlusion

Bilateral pallor of the optic disks was observed in a 52-year-old man after dissection of an internal carotid artery. Diffuse pallor of the ipsilateral optic disk reflected infarction of the ipsilateral optic nerve and "bow-tie" atrophy of the contralateral optic disk reflected infarction of the ipsilateral optic tract. The findings were due to an occlusion of the internal carotid artery proximal to the origin of the ophthalmic artery, resulting also in insufficiency in the area of supply of the anterior choroidal artery.     

Accidental occlusion of the common femoral artery after Angio-Seal-application]

Multiply-antibiotic-resistant isolates of serogroup 19 Streptococcus pneumoniae, possessing altered penicillin-binding protein (PBP) 1A, 2B, and 2X genes that are indistinguishable from those of the Spanish multiresistant serogroup 23F clone, are now commonly encountered in Spain. Those isolates that have been serotyped express type 19F capsular polysaccharide. Serotyping of further isolates, and hybridization using a serotype 19F-specific probe, has shown that some of them are serotype 19A, rather than 19F. The Spanish multiresistant serotype 19A, 19F, and 23F multiresistant strains were all shown to be very closely related in overall genotype, as they were indistinguishable by REP-PCR and by the sequencing of internal fragments of three house-keeping genes. The serotype 19A multiresistant strains, like the serotype 19F multiresistant strains, therefore appear to be a serotype variant of the Spanish multiresistant serotype 23F clone, which presumably has arisen by recombination at the capsular locus.     

Atypical beta-adrenoceptors in the rat isolated common carotid artery

1. The possible existence of atypical beta-adrenoceptors in vascular smooth muscle of the rat common carotid artery was examined in this study. 2. Isoprenaline produced concentration-dependent relaxation of noradrenaline (10(-7) M) precontracted ring segments of the carotid artery. The relaxation was not affected by endothelial denudation. 3. Propranolol (10(-8) M-3 x 10(-7) M) shifted the isoprenaline curve to the right without suppressing the maximum response. However, the slope (0.74) of the Schild plot was significantly (P < 0.05) less than 1. 4. Salbutamol (beta 2), CGP 12177 and BRL 37344 (beta 3) also concentration-dependently relaxed noradrenaline precontracted artery segments. These relaxations were not affected by propranolol (10(-7) M). Pretreatment of the artery segments with BRL 37344 did not desensitize the tissue to the relaxant effect of isoprenaline, CGP 12177 and salbutamol. 5. It is concluded that atypical beta-adrenoceptors exist in vascular smooth muscle of the common carotid artery.     

Extrathoracic bypass procedures for proximal common carotid artery lesions

During a 10-year period ending in December 1991, 31 extrathoracic bypass procedures were performed in 29 patients for proximal common carotid artery atherosclerotic stenosis or occlusion. This included 16 men and 13 women, with a mean age of 63 years. Indications for surgery included transient ischemic attacks in 23 patients (79%), nonfocal symptoms in 4 patients (14%), and asymptomatic proximal common carotid artery stenosis associated with near-total occlusion of the internal carotid artery in 2 patients (7%). Severe proximal stenosis or complete occlusion of the common carotid artery was demonstrated angiographically in all cases. Subclavian-to-carotid bypass was performed in 26 cases and carotid-to-carotid bypass in 5 cases. Seventy-four percent of the bypass procedures were to the common carotid artery and 26% to the external carotid artery. Endarterectomy of the common carotid bifurcation was performed in conjunction with the bypass procedure in 13 cases and vertebral artery transposition in 2 other cases. Saphenous vein was used as the bypass conduit in 65% and prosthetic grafts in 35% of cases. There were no perioperative strokes or deaths in this series, and the mean postoperative hospital stay was 5 days. Follow-up ranged from 2 to 118 months (mean: 38.4 months). Graft occlusion occurred in two cases during the follow-up period (3-year patency rate: 90%), with recurrence of symptoms in one patient, which necessitated revision. Three patients had persistence or recurrence of symptoms despite patency of the graft, one other patient sustained a posterior circulation infarct, and there was one death unrelated to carotid vascular disease during the follow-up period. This experience shows that extrathoracic bypass procedures are safe and well tolerated for symptomatic proximal common carotid artery stenosis or occlusion. This method of reconstruction has excellent long-term patency and protection against further anterior circulation neurologic events.