Giorgos S. Sfyroeras

Hyperperfusion syndrome after carotid revascularization

Cerebral hyperperfusion syndrome is a rare, serious complication of carotid revascularization either after carotid endarterectomy or carotid stent placement. Impaired cerebral autoregulation and post-revascularization changes in cerebral hemodynamics are the main mechanisms involved in the development of the syndrome. Hyperperfusion syndrome may be fatal once an intracranial hemorrhage occurs. This article reviews the literature, intending to make a synthesis of all new data concerning the clinical manifestations of hyperperfusion syndrome, the pathophysiologic pathways involved in its development, the prediction, and the appropriate management. Also, a review of the most recent series of hyperperfusion syndrome following carotid revascularization, both with classic open endarterectomy and carotid artery stenting has been performed.

Endovascular Treatment of Popliteal Artery Aneurysms

OBJECTIVE To present the results of the endovascular treatment of popliteal artery aneurysms. METHODS From April 1999 to January 2002, 11 patients, aged 40-94 years, with 12 popliteal aneurysms were treated. Nine (75%) underwent an endoluminal repair, of whom three were done emergently due to an aneurysm rupture. Aneurysm diameter was 28-105 (mean 69) mm. A Hemobahn stent graft was inserted in six, Wallgraft in two and Passager in one case. RESULTS During a mean follow-up of 14 (3-31) months, four (44%) thromboses occurred: two in the early postoperative period (30 days) and two during the late postoperative period. Two of the four occluded grafts were successfully reopened, and in the one a stenosis of the distal end of the stent graft was treated with balloon dilatation. Patency rates at 1 and 12 months were 64/47% (primary patency) and 88/75% (secondary patency), respectively. CONCLUSION Initial experience with endovascular treatment of the popliteal aneurysm in high-risk patients yielded modest results. Larger number of patients and further follow-up time is necessary to evaluate the long-term results.

Impact of Endograft Material on the Inflammatory Response After Elective Endovascular Abdominal Aortic Aneurysm Repair

The purpose of this paper is to examine the impact of endograft material on the inflammatory response after elective endovascular abdominal aortic aneurysm repair. Consecutive patients (n=22, all men, 53 to 82 years old) were divided into 2 groups according to the graft material used: In group A (n=12) the endovascular device was made of polyester and in group B (n=10) the device was made of expanded polytetrafluoroethylene (ePTFE). All patients received antiinflammatory drugs in the perioperative period. Fever, white blood cells and platelet count, serum concentrations of cytokines (interleukin 6 [IL-6], tumor necrosis factor alpha [TNF-a], interleukin 8 [IL-8], acute-phase proteins high-sensitivity C-reactive protein [hsCRP] and alpha1-antitrypsin [a1-antitrypsin]), and complement protein (C3a) were measured preoperatively and 1, 3, 6, 24, 48, and 72 hours after aneurysm exclusion. One patient in each group had a systemic inflammatory response syndrome with 2 of the systemic inflammatory response syndrome (SIRS) criteria. No other complication associated with inflammation were present in any patient. Fever was more frequent in group A patients. Increases of white blood cells and serum concentrations of IL-6, TNF-a, hsCRP, a1-antitrypsin, and C3a and decrease of platelet count were recorded in both groups, but no statistically significant difference between them was recorded. However, serum concentrations of IL-8 were significantly higher in group A patients 24 hours postoperatively (p=0.01). No significant difference was apparent in the biological response between patients receiving a polyester or an ePTFE stent graft, except for fever and serum concentrations of IL-8.

Renal artery thrombosis caused by stent fracture in a single kidney patient.

Purpose: To report a case of incomplete expansion, fracture, and thrombosis of a stent in the renal artery. Case Report: A 47-year-old man with right renal artery occlusion underwent direct stenting of the left renal artery using a balloon-expandable stent. Completion angiography showed satisfactory patency of the vessel although the stent was not fully expanded in its central segment. The patient received 5000 units of heparin during the procedure, but no additional anticoagulant or antiplatelet therapy in the peri/postinterventional period. Twenty-five days later, he presented with acute renal insufficiency and uncontrolled hypertension. Angiography revealed in-stent thrombosis and collateral flow in the distal segment of the left renal artery. He underwent an aortorenal bypass, which salvaged the kidney. The stent, after removal from the vessel, was fractured and not completely expanded. Conclusions: Incomplete expansion and fracture of the stent associated with insufficient antiplatelet therapy produced in-stent thrombosis. Collateral flow prevented kidney necrosis.

Endovascular Exclusion of Symptomatic Bilateral Common Iliac Artery Aneurysms with Preservation of an Aneurysmal Internal Iliac Artery via a Reverse-U Stent-Graft

Purpose: To report a technique to maintain flow to an aneurysmal internal iliac artery (IIA) when treating bilateral common iliac artery (CIA) aneurysms with an aortomonoiliac stent-graft and femorofemoral bypass. Technique: First, an external iliac artery (EIA) to IIA endograft is placed distal to the IIA aneurysm then the contralateral IIA is embolized with coils. An aortomonoiliac stent-graft extending to the contralateral EIA is placed, and the procedure is completed with a femorofemoral bypass. Conclusion: Endovascular treatment of bilateral CIA aneurysms and combined with a unilateral IIA aneurysm is a technically demanding procedure. An endovascular repair with retrograde (reverse-U stent-graft) hypogastric artery preservation can be considered a first choice until the use of branched iliac stent-grafts becomes more widespread.

A meta-analysis of combined endarterectomy and proximal balloon angioplasty for tandem disease of the arch vessels and carotid bifurcation

OBJECTIVE High grade stenoses of both the innominate (IA) or common carotid artery (CCA) and the carotid bifurcation are rare and represent a therapeutic dilemma for the treating physician. A hybrid procedure with concomitant carotid endarterectomy (CEA) and retrograde angioplasty has been proposed as a less invasive treatment option. The aim of this study is to review the existing literature on such hybrid procedures. METHODS An electronic search of the pertinent English literature was undertaken. A meta-analysis of all studies reporting on simultaneous carotid endarterectomy and retrograde angioplasty for the treatment of tandem internal carotid and proximal common carotid or innominate artery lesions was performed. RESULTS Thirteen studies, including 133 patients were identified. Sixty-eight percent of the patients were male, 83% symptomatic. Proximal lesions were located in ipsilateral CCA in 85 cases and in IA in 48 cases. Reported technical success of the procedure was 97%. In 79 of the 129 successful operations, a stent was implanted, while the remaining 50 patients underwent simple balloon angioplasty. Thirty-day mortality and stroke rate were 0.7% and 1.5%, respectively. Combined 30-day mortality and stroke rate was 1.5%. During a mean follow-up of 12 to 36 months, five patients presented symptoms of cerebral ischemia and 17 died. Ten patients developed restenosis of the proximal lesion, (4 symptomatic, 7 in cases without stent) and 2 restenoses of the endarterectomy (all asymptomatic). Restenosis was treated in 7 cases (4 repeat angioplasty, 3 bypass grafts). CONCLUSIONS This meta-analysis reports the largest collection of patients having undergone hybrid treatment of tandem disease of the arch vessels and carotid bifurcation. Results from this study show that the combined stroke and death rate with this approach is equal to or better than that for isolated endarterectomy. When possible, balloon angioplasty with stenting of the proximal component of this disease should be pursued to avoid restenosis.

Cerebral Hyperperfusion After Carotid Stenting: A Transcranial Doppler and SPECT Study

Aim: To document the incidence of symptomatic cerebral hyperperfusion after carotid stenting and to determine possible predisposing factors. Methods: A prospective study of 29 consecutive patients undergoing carotid stenting. All patients underwent 1) brain computed tomography scan and magnetic resonance imaging, 2) transcranial Doppler including assessment of cerebrovascular reactivity of the ipsilateral middle cerebral artery and 3) 99m hexamethyl-propyleneamine oxime brain single photon emission computed tomography, before and after the procedure. Results: A total of 5 patients developed adverse neurological events, 4 of them transient. Cerebral hyperperfusion was documented in two of these (6.9%). Both had exhausted cerebrovascular reactivity in the preoperative transcranial Doppler examination. No consistent pattern of interhemispheric asymmetry in brain perfusion was found in these patients. Conclusions: Symptomatic cerebral hyperperfusion is not uncommon after carotid stenting. There seems to be a link between exhausted cerebrovascular reactivity of the ipsilateral middle cerebral artery and increased risk of cerebral hyperperfusion.

Interhemispheric asymmetry in brain perfusion before and after carotid stenting: a 99mTc-HMPAO SPECT study.

Purpose: To assess the effect of unilateral carotid angioplasty and stenting (CAS) on cerebral perfusion asymmetry in patients with severe extracranial carotid stenosis by means of technetium Tc 99m hexamethyl-propyleneamine oxime brain single photon emission computed tomography (99mTc-HMPAO SPECT). Methods: Twenty-nine consecutive patients (22 men; median age 68 years, range 58–80; 13 symptomatic) undergoing unilateral CAS were included in the study. Brain perfusion was assessed by 99mTc-HMPAO brain SPECT prior to the procedure and postoperatively at 8 hours and at 2 to 4 months. The asymmetry index (AI), a measure of the interhemispheric asymmetry in perfusion, was calculated as [(counts in “healthy” hemisphere—counts in hemisphere with carotid stenosis)/counts in “healthy” hemisphere]x100. Results: The preoperative AI demonstrated a wide variation (mean −0.5%±8.4%, range −19.5% to 14.1%). There was no significant correlation between the degree of carotid stenosis and preoperative AI. The mean preoperative AI in the asymptomatic patients was lower than in the symptomatic group [-4.0%±8.5% (range −19.5% to 8.2%) versus 3.8%±6.4% (range −5.2% to 14.1%), p=0.01], suggesting reduced perfusion of the ipsilateral cerebral hemisphere compared to the contralateral side in symptomatic patients. AI variation did not improve after CAS; there was no difference in AI among the 3 SPECT studies (p=0.75). Preoperative AI correlated significantly with late AI (r=0.74, p<0.0001); however, there was no statistically significant correlation between immediate postoperative AI and either preoperative (r=0.24, p=0.217) or late (r=0.24, p=0.249) AI. Conclusion: Asymmetry in cerebral perfusion in patients with severe extracranial carotid atherosclerosis does not correlate with the degree of carotid stenosis. Symptomatic patients demonstrate compromised perfusion of the ipsilateral hemisphere compared to asymptomatic patients. As judged by 99mTc-HMPAO SPECT scanning, cerebral perfusion patterns do not significantly change after CAS.

Abdominal endograft collapse with acute bilateral lower limb ischemia.

This particular case shows that migration of an initially correctly placed AMPLATZER device can occur especially if open surgery and mechanical manipulation around the occluded vessel are performed. Additionally, when a firstgeneration AMPLATZER plug is fully expanded, the spaces between the wire meshes can remain widely open and flow through the device without any symptoms might persist, especially in the pulsatile, high-pressure arterial system. In such a clinical condition, a conservative management is a valuable option analogous to the asymptomatic outcome of migrated bare stents into the pulmonary circulation (5); however, in potential similar cases with a migrated last-generation AMPLATZER plug, conservative management may be unadvisable because of the higher risk of early or late severe thromboembolic complications, as last-generation AMPLATZER plugs (6) have more and denser layers of wire meshes, making persistent flow over time less likely.

Endovascular Treatment of a Ruptured Para-Anastomotic Aneurysm of the Abdominal Aorta

We report a case of a ruptured para-anastomotic aortic aneurysm treated with implantation of a bifurcated stent-graft. A 72-year-old patient, who had undergone aortobifemoral bypass for aortoiliac occlusive disease 16 years ago, presented with a ruptured para-anastomotic aortic aneurysm. A bifurcated stent-graft was successfully deployed into the old bifurcated graft. This is the first report of a bifurcated stent-graft being placed through an “end-to-side” anastomosed old aortobifemoral graft. Endovascular treatment of ruptured para-anastomotic aortic aneurysms can be accomplished successfully, avoiding open surgery which is associated with increased mortality and morbidity.