Proximal arterial occlusion protects the distal lower limb vessels.

PURPOSE: To test the hypothesis that chronic arterial occlusion protects the distal vessels from disease progression. METHODS: Peripheral angiograms from the radiology film store filed under 1997-1999 were reviewed. Those showing unilateral iliac occlusion and those showing unilateral femoro-popliteal occlusion were selected. The severity of arterial disease distal to the occlusion was compared with the patent side. Subsequently, in a subgroup of patients undergoing repeat angiography, the frequency and distribution of disease progression was recorded and related to the initial disease distribution. RESULTS: In the presence of a unilateral iliac occlusion, femoro-popliteal occlusion was less likely on the side of the iliac occlusion than on the opposite side (difference in proportion 10%. 95% C.I.: 1-18%). In the presence of a unilateral occlusion proximal to the knee joint, there were more patent calf vessels on the side of the occlusion than on the opposite side (difference in proportion 9%. 95% C.I.: 4-14%). When angiography was repeated, progression of calf vessel disease was less common in the limbs with untreated proximal occlusion than in those with no proximal occlusion. CONCLUSION: Proximal arterial occlusion protects the distal vessels from the risk of progressive arterial disease.     

Common carotid occlusion for unclippable carotid aneurysms: an old but still effective operation

We present a selected series of nine patients with unclippable internal carotid artery aneurysms to illustrate our current approach to this problem. Eight of the nine underwent common carotid ligation after preoperative angiographic evaluation. Tolerance to carotid occlusion was determined intraoperatively by awake examination, electroencephalogram (EEG) monitoring, and carotid stump pressure measurements. No patient developed a permanent deficit; seven of eight treated aneurysms have thrombosed. Our experience and review of the literature indicate that most ischemic complications after carotid ligation seem to be thromboembolic, rather than due to "low flow" from poor collateral circulation. For this reason, we have gradually come to favor common carotid (CCA) over internal carotid (ICA) occlusion in many of these patients. After CCA occlusion, the ICA frequently remains open and embolic complications are therefore less likely. An extracranial-intracranial bypass procedure is performed only in those patients with poor collateral circulation demonstrated by cross compression angiographic studies, by the development of new deficits during test occlusion, or by the appearance of EEG changes during test occlusion. We suggest that CCA ligation remains a useful alternative in the management of unclippable internal carotid aneurysms.     

Unilateral development of moyamoya vessels after contralateral cervical internal carotid artery occlusion. Case report]

A 41-year-old female suffered transient ischemic attack. Cerebral angiography revealed occlusion of the left internal carotid artery at the cervical portion and collateral pathways consisting of transpial anastomosis and parenchymal anastomosis from the posterior circulation. Five years later, the second angiography was carried out. Left carotid angiography revealed appearance of transdural anastomosis from the middle meningeal artery and the anterior ethmoidal artery. Right carotid angiography revealed severe stenosis at the carotid fork with moyamoya vessels. Bilateral encephalomyo-arterio-synangiosis was performed for revascularization. Postoperative bilateral carotid angiograms revealed good neovascularization on both sides. In typical moyamoya disease, occlusive change of the carotid fork with moyamoya vessels appeared symmetrically and simultaneously on both sides. Although this case is not a typical moyamoya disease, its pathogenesis is quite similar to that of moyamoya disease.     

Enlargement and rupture of distal basilar artery aneurysm after iatrogenic carotid occlusion

A case of angiographic enlargement and fatal rupture of a previously asymptomatic distal basilar aneurysm in a 12-year-old girl is reported. She had been treated by carotid sacrifice for a giant intracavernous carotid aneurysm. After superficial temporal-middle cerebral artery bypass, this patient underwent a trapping procedure and decompression of her symptomatic giant aneurysm. Despite postoperative patency of her bypass graft, the involved middle cerebral circulation was irrigated substantially by retrograde flow through her posterior communicating artery. An incidental distal basilar aneurysm involving the origin of her superior cerebellar arteries, posterior cerebral arteries, and multiple perforators was treated by a wrapping procedure. Eleven days after carotid ligation, she suffered a fatal subarachnoid hemorrhage from her basilar aneurysm. This catastrophe was undoubtedly produced by our failure to consider the additional hemodynamic stress placed upon the distal basilar artery by carotid sacrifice and may have been preventable by a more aggressive attack on this previously asymptomatic lesion.     

Hemodynamic conditions at the carotid bifurcation during protective common carotid occlusion.

OBJECTIVES: Carotid angioplasty and stenting procedures are associated with an obligatory release of particulate debris into the distal cerebral circulation. Although most of the emboli are small and do not result in symptomatic neurologic deficits, some may be large enough to cause stroke. For this reason, a variety of filters and balloon occlusion devices have been employed as adjuvants to decrease the risk of distal embolization during carotid stenting. Some of these devices rely on the arrest of antegrade blood flow with the use of inflow arrest. The present study was undertaken to investigate the hemodynamic conditions that exist at the carotid bifurcation during common carotid artery (CCA) occlusion. METHODS: Internal carotid artery (ICA) and external carotid artery (ECA) stump pressures were measured in 29 patients undergoing carotid endarterectomy. Duplex ultrasound scanning was used to measure the direction and velocity of blood flow in the ICA and ECA with the CCA cross-clamped but the ICA and ECA open, a clinical scenario analogous to CCA balloon occlusion at the time of carotid angioplasty and stenting. The direction and magnitude of ICA and ECA flow were compared with the stump pressures to determine whether a correlation existed between these variables. RESULTS: The mean stump pressure in the ICA and ECA averaged 56 +/- 16 and 53 +/- 12 mm Hg, respectively. The ICA systolic stump pressure was lower than the ECA systolic stump pressure in six patients (21%), and all of these patients had persistent antegrade systolic duplex blood flow by duplex interrogation during CCA occlusion. The ICA systolic stump pressure exceeded the ECA systolic stump pressure in 19 patients (66%), and all of these patients had retrograde ICA flow during systole. Diastolic flow was also well correlated with the magnitude of the ICA/ECA stump pressure differential, with antegrade diastolic ICA blood flow in all nine patients with an ICA diastolic stump pressure less than the ECA diastolic stump pressure. None of the 10 patients with ICA diastolic stump pressure greater than ICA diastolic stump pressure maintained antegrade ICA diastolic flow, but four of these patients had flow to zero in diastole. Overall, 13 of 29 patients (45%) could be surmised to be at risk for distal embolization to the brain based on the persistence of some element of either systolic or diastolic antegrade ICA flow during common carotid occlusion. CONCLUSIONS: Common carotid occlusion alone appears insufficient to protect against distal embolization during manipulations of the carotid bifurcation. Persistent systolic or diastolic antegrade blood flow occurs in a high proportion of patients, lending credence to the use of additional protective strategies to ameliorate the risk of embolic complications.     

A case of distal posterior cerebral artery aneurysm associated with occlusion of the internal carotid artery

Hemodynamic stress is considered one of the most important factors in the growth of cerebral aneurysms. The authors report a rare case of cerebral aneurysm located at the distal posterior cerebral artery (PCA) in which collateral circulation developed due to occlusion of the internal carotid artery (ICA). A 73-year-old male was admitted to our hospital with a sudden headache and nausea. Computerized tomography (CT) revealed an intracerebral hematoma in the right parieto-occipital lobe and the acute subdural hematoma in both the cerebral interhemispheric fissure and the convexity. Moreover, angiography revealed a saccular aneurysm at the P4 portion of the PCA. The right ICA was occluded at the cervical portion and collateral circulation which had developed in the PCA was extended to the region of the right middle cerebral artery. The aneurysm was clipped 15 days after admission without new neurological complications. This case demonstrates that increased hemodynamic stress plays a role in the growth and rupture of cerebral aneurysm.     

Microblock for occlusion of small vessels. Technical note.

A small microvascular occluder termed a "microblock" is described. It has the advantages of controlled gentle occlusion and small size.     

Superiority of balloon occlusion arteriography to reactive hyperemic arteriography in visualization of distal lower limb vessels

Balloon occlusion arteriography was performed in 38 lower limbs; reactive hyperemic arteriography was also performed in 16 of these limbs. To assess the safety and utility of this technique the balloon occlusion arteriograms of all 38 patients were reviewed retrospectively by a vascular surgeon and vascular radiologist who were unaware of the patient's identity and ultimate treatment. After the arteriograms were reviewed and the outflow vessels identified, a decision was made regarding operability and optimal recipient vessel for distal bypass. Twenty-two of the 38 patients underwent balloon occlusion arteriography only, and 21/22 (95.5%) of these patients only had studies deemed adequate for surgical planning. Twelve of the 16 (75%) patients underwent both reactive hyperemic arteriography and balloon occlusion arteriography; potential distal outflow vessels not seen on reactive hyperemic arteriograms were observed on balloon occlusion arteriograms. In only 4/16 (25%) patients the balloon occlusion arteriograms did not yield additional information. No complications were associated with this technique. Approximately 8.5 g of iodine per run is used for balloon occlusion arteriography compared with approximately 37 g of iodine per run for reactive hyperemic arteriography. Balloon occlusion arteriography is a safe and accurate adjunctive technique that can be used when identification of lower limb vessels is critical.Presented at the Seventeenth Annual Meeting of the Peripheral Vascular Surgery Society, Chicago, Ill., June 7, 1992.     

Penetrating trauma to the carotid vessels

Over a 13 year period extending between April 1975 and June 1988, 510 neck injuries were treated at the American University of Beirut Medical Center; the carotid vessels were involved in 48 patients, resulting in 53 carotid injuries. The mean age of the patients was 25.3 years and shrapnel injuries were the commonest (45.8%), followed by bullet wounds (33%). Thirty-nine patients had a laceration and five had complete disruption of the carotid vessels and only three presented in coma. Shock was present in 14 patients, of whom five had a neurological deficit. In six the injured vessels were ligated, three of them were external carotid arteries. Nine patients were not initially operated on. Six of them had a chronic arterio-venous fistula and three were in coma. The remainder underwent surgical repair. Nine patients died, giving an overall mortality rate of 18.8%. Four of these died because of multisystem failure, thus giving a 10.4% mortality rate for the isolated carotid injury. There was definite improvement in the repaired group, but the haemodynamic status seemed to significantly affect the mortality rate (P less than 0.01). Follow-up of surviving patients has revealed five with persistent neurological deficits in the repaired group (33 patients), and four patients with a chronic arterio-venous fistula. Two patients had a false aneurysm. Carotid artery injury seems to have a good prognosis if repaired promptly within 3 h.     

Management of the near total internal carotid artery occlusion.

OBJECTIVES: The risk of stroke in patients with near total internal carotid artery (ICA) occlusion is perceived to be high as stroke risk increases with severity of the stenosis. The management of this entity has not been addressed specifically in the existing randomised trials and thus it remains controversial. METHODS: Systematic review of the relevant literature. RESULTS: The management of patients with near total ICA occlusion remains controversial: some favour intervention whereas others have condemned it as dangerous or of no benefit. A prospective multicentre randomised trial regarding intervention versus best medical treatment for patients with symptomatic near total ICA occlusion seems difficult because of the large number of patients required to power the study. Nevertheless, it appears hard to decline surgery based on the current evidence. CONCLUSIONS: Because of the current controversy over the best management of the near total ICA occlusion, prospective observational studies are needed to demonstrate its prevalence in the symptomatic and asymptomatic population and any associated excess stroke risk. Based on the current evidence, surgery is the treatment of choice in most centres but its validity over best medical treatment remains untested.     

Acute embolic occlusion of the distal aorta

PURPOSE: Acute occlusion of the abdominal aorta requires rapid diagnosis and intervention to prevent loss of life or limb. The overall mortality due to embolic occlusion is reported to be over 30%. The most common source of emboli is the heart, secondary to atrial fibrillation or myocardial infarction. METHODS: A patient is herein presented who arrived at the emergency department 6 hours after onset of classic signs of acute arterial occlusion. RESULTS: She had a saddle embolus of the distal abdominal aorta with extension of the clot into both iliac and femoral arteries. CONCLUSIONS: Heparin therapy and embolectomy successfully reestablished blood flow. The etiology, presentation and management of aortoiliac occlusion is discussed.     

Microsurgical approach to bilateral carotid artery occlusion.

Bilateral thromboses of the carotid artery present in the form of complete bilateral occlusion or in the form of unilateral occlusion associated with stenosis of the contralateral carotid artery. From our experience in a series of 20 patients extra-intracranial microanastomosis appears to be effective in both described groups.     

Anomalous branch of the internal carotid artery maintains patency distal to a complete occlusion diagnosed by duplex scan

A 67-year-old man had symptoms of peripheral vascular disease and was noted to have a carotid bruit. Duplex ultrasound examination of the neck demonstrated a short segmental occlusion of the proximal internal carotid artery (ICA) with antegrade flow distal to the occlusion maintained by an anomalous branch of the ICA. Angiography confirmed the findings and suggested that the branch was from the distribution of the occipital artery. The ICA findings were surgically proved, and endarterectomy was successfully performed without complication. This case reinforces the usefulness of duplex ultrasonography of the carotid arteries and is a rare situation in which a completely occluded ICA can be repaired with a good clinical outcome. (J Vasc Surg 1997;26:164-7.)     

Atherosclerotic carotid artery occlusion

Opinion statement Patients with acute stroke caused by atherosclerotic carotid artery occlusion (ACAO) should receive intravenous tissue plasminogen activator if they meet eligibility criteria. Patients with acute stroke caused by ACAO who are not eligible for intravenous tissue plasminogen activator should receive aspirin. Heparin or heparin-like drugs do not improve outcome and should not be used. Therapy for prevention of recurrent stroke in patients with ACAO should consist of lifestyle modifications, risk factor intervention, and aspirin. Other antiplatelet drugs should be considered in patients with contraindication to aspirin. Warfarin is not indicated. Extracranial-intracranial bypass surgery provides no benefit over medical therapy in preventing recurrent stroke in a general population of patients with ACAO or in any subgroups selected by clinical or arteriographic criteria. Extracranial-intracranial bypass surgery in patients selected by hemodynamic criteria should only be performed as part of a randomized controlled clinical trial. Other surgical or endovascular procedures have no proven value in treating or preventing stroke caused by ACAO. Asymptomatic carotid occlusion has a benign prognosis, and requires no specific treatment other than lifestyle modification and risk factor intervention.     

Outcome of progression from carotid stenosis to occlusion.

The incidence of symptoms at the moment the internal carotid artery (ICA) occludes was assessed in 33 patients. Duplex scanning was performed to determine the progression from stenosis to ICA occlusion. There were 24 patients with a primary stenosis and nine with a restenosis after a carotid endarterectomy. In 18% (6/33) the occlusion was accompanied by a stroke. A transient ischaemic attack (TIA) was seen in 12% (4/33) of patients and 70% (23/33) remained asymptomatic. There was no difference in stroke rate between patients with primary stenosis (4/24:17%) and those with restenosis (2/9:22%). The mean follow-up was 3.2 years and the mean elapse time to occlusion in patients with a stroke was 20 months, with a TIA, 32 months, and in asymptomatic patients, 44 months. It was also shown that a stenosis of greater than 80% diameter reduction had a faster progression (mean 1 year) than a less than 80% stenosis (mean 3.5 years) (p = 0.04). Patients with a stenosis greater than 80% tended to have a higher incidence (40%:2/5) of stroke at the time of occlusion than patients with a stenosis less than 80% (14%:2/28). The results show that an occlusion of the ICA is accompanied by a stroke in 18% of the cases and that patients with a rapid progression and/or greater than 80% stenosis are at high risk. From this point of view a carotid endarterectomy should be considered in order to prevent an occlusion of the ICA and a high risk of stroke.     

Stenosis of one carotid artery with occlusion of the contralateral carotid

Summary 23 patients with unilateral internal carotid artery stenosis (>70%) and contralateral internal carotid artery occlusion in the neck are reported. The symptoms are referable to the side of the occlusion in 13 cases (57%), to the side of stenosis in 7 cases (30%) and non-localizing in 3 cases (13%). All 23 patients had a carotid endarterectomy performed on the side of the stenotic lesion. There was no operative mortality. Late neurological symptomatology after surgery was referable to the side of stenosis in 13% and to the side of occlusion in 9%. The authors consider that, in cases of significant stenosis (greater than 70%) of an internal carotid artery with a contralateral occlusion, preference should always be given to endarterectomy of the stenotic side, reserving extra-intracranial by-pass of the occluded side for patients who remain symptomatic after endarterectomy of the stenotic side.