Innominate vein stenosis causing raised intracranial pressure and blindness

Bilateral Dilated Superior Ophthalmic Veins in a Patient With an Arteriovenous Dialysis Fistula

A 64-year-old man presented with 4 months of diplopia. He had end-stage renal disease requiring a cephalic transposition brachiocephalic fistula that was no longer in use following successful renal transplantation. On presentation, he had bilateral proptosis, extraocular movement restriction, chemosis, tortuous episcleral vessels, and caruncular injection. Non-contrast CT of the orbits demonstrated dilation of both superior ophthalmic veins, and CT angiography showed asymmetric enlargement of both cavernous sinuses and superior ophthalmic veins. A carotid-cavernous fistula was suspected, but cerebral angiography revealed shunting from the old fistula with intracranial drainage and cerebral venous hypertension. Aberrant retrograde drainage resulted from anatomical compression of the left brachiocephalic vein. The fistula was ligated, and at 1-week follow-up, the patient had marked improvement in extraocular movements and orbital congestion with near complete resolution of diplopia. Postoperative CT angiography obtained 2 months later demonstrated decreased size of both superior ophthalmic veins, consistent with improvement of venous hypertension.

Management of Central Venous Stenoses and Occlusions

Symptomatic central venous stenosis and occlusion remains the gordian knot of vascular access. Advances in techniques, like sharp recanalization, allowed for improved success rates in crossing these difficult lesions. There is also increasing evidence of new devices in treating central venous stenosis and, at the same time, improving the time needed between interventions. High-pressure balloons, paclitaxel-coated balloons, bare metal stents and covered stents have been tested with an aim to offer additional treatment options, although obstacles still exist. In the current review, authors describe relevant techniques and options, provide the evidence and evaluate the actual implementation of these devices in this demanding field.

Computational fluid dynamics simulation of hemodynamic changes in a hemodialysis patient with central venous stenosis treated with stent

BACKGROUND

It has not been demonstrated that computational fluid dynamics (CFD) can be used to model central venous stenosis (CVS), nor that hemodynamic changes in CVS treated with stent placement can be anticipated. The purpose of this study was to demonstrate the hemodynamic performance of CVS patients treated with stent placement.

METHODS

Patient-specific geometric models were constructed using computed tomography images of veins from hemodialysis patients treated with stent placement. CFD simulation based on geometry was performed using ANSYS-15 to compare pressure quantitatively, wall shear stress (WSS), and flow velocity in the brachial vein before and after stent placement.

RESULTS

Following a covered stent placement, the swelling of the left upper extremity was relieved. Prior to stent implantation, the maximum and mean brachial vein wall pressures were 465.2 Pa and 224.609 Pa, respectively. It was determined that the maximum WSS value was 8.449 Pa and that the mean WSS value was 0.743 Pa. The maximum and mean flow velocities were 1.16 and 0.173 m/s, respectively. After stent placement, the maximum wall pressure, maximum WSS, and maximum flow velocity dropped by 59.4%, 71.2%, and 57.8%, respectively. The mean wall pressure, mean WSS, and mean flow rate decreased by 43.5%, 52.7%, and 17.6%, respectively.

CONCLUSION

Hemodynamics of CVS in hemodialysis patients exhibited turbulent, imbalances and disorders, which can be improved by stent placement.

Dilatation of Superior Ophthalmic Vein and Visual Disturbance by Central Venous Stenosis: A Case Mimicking Cavernous Sinus Dural Arteriovenous Fistula

투석 환자에서 중심정맥협착은 비교적 흔한 합병증이나, 이로 인한 경정맥역류 및 두개내압 상승은 드물며, 진행성 시력 저하를 보이는 경우는 몇 개의 증례만 보고되고 있다. 저자들은 경정맥역류로 인한 두개내압 상승, 시력 저하 그리고 뇌 MRI에서의 상안정맥 확장에 대해 해면경막 동정맥루로 오인하였던 증례를 보고하고자 한다. 환자는 time-of-flight MR angiography (이하 TOF-MRA)에서 경정맥역류 소견이 있었고, 혈관조영술에서 좌측 완두정맥의 협착이 확인되었다. 중심정맥협착에 대해 풍선혈관성형술을 시행하였고 증상이 호전되어 퇴원하였다. 중심정맥협착에 의한 경정맥역류와 해면경막 동정맥루는 유사한 증상을 보일 수 있으나 치료법이 다르므로, MRI와 TOF-MRA의 면밀한 검토를 토대로 영상의학적으로 감별하는 것이 중요하며, 뇌혈관조영술을 통해 중심정맥협착 유무를 확인하는 것이 필요하다.

Reversible Encephalopathy Due to Venous Hypertension From Arteriovenous Hemodialysis Graft

Venous congestive encephalopathy is a rare complication in patients with arteriovenous hemodialysis grafts. It commonly manifests as encephalopathy of fluctuating severity, often with seizures. Because these patients typically have multiple significant chronic health problems, venous hypertension's contribution to the patient's cognitive decline can easily be overlooked. This nonspecific presentation can make diagnosis challenging, therefore delaying treatment. We describe a case of progressive, fluctuating encephalopathy with seizures due to cerebral venous congestion caused by arterial shunting from an upper limb arteriovenous (AV) fistula to the proximal venous system, that was initially unrecognized, yet ultimately reversed by elimination of the source of venous hypertension.