Multiple Re-entry Closures After TEVAR for Ruptured Chronic Post-dissection Thoraco-abdominal Aortic Aneurysm

Introduction

Although thoracic endovascular aortic repair (TEVAR) has become a promising treatment for complicated acute type B dissection, its role in treating chronic post-dissection thoraco-abdominal aortic aneurysm (TAA) is still limited owing to persistent retrograde flow into the false lumen (FL) through abdominal or iliac re-entry tears.

Report

A case of chronic post-dissection TAA treatment, in which a dilated descending FL ruptured into the left thorax, is described. The primary entry tear was closed by emergency TEVAR and multiple abdominal re-entries were closed by EVAR. In addition, major re-entries at the detached right renal artery and iliac bifurcation were closed using covered stents. To close re-entries as far as possible, EVAR was carried out using the chimney technique, and additional aortic extenders were placed above the coeliac artery. A few re-entries remained, but complete FL thrombosis of the rupture site was achieved. Follow-up computed tomography showed significant shrinkage of the FL.

Discussion

In treating post-dissection TAA, entry closure by TEVAR is sometimes insufficient, owing to persistent retrograde flow into the FL from abdominal or iliac re-entries. Adjunctive techniques are needed to close these distal re-entries to obtain complete FL exclusion, especially in rupture cases. Recently, encouraging results of complete coverage of the thoraco-abdominal aorta with fenestrated or branched endografts have been reported; however, the widespread employment of such techniques appears to be limited owing to technical difficulties. The present method with multiple re-entry closures using off the shelf and immediately available devices is an alternative for the endovascular treatment of post-dissection TAA, especially in the emergency setting.

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A case of ruptured post-dissection thoraco-abdominal aneurysm was treated.

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Following entry closure by TEVAR, EVAR was performed to close multiple re-entries.

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Re-entries at the renal artery ostium and iliac artery were closed by covered stents.

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Complementary re-entry closure techniques are essential to treat false lumen rupture.

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This report demonstrates successful re-entry closure techniques following TEVAR.

Development of a platform to evaluate and limit in-stent restenosis

The objective of this work was to develop a platform to evaluate and deliver putative therapeutic agents for in-stent restenosis. Arterial stenting is applied in more than 60% of balloon angioplasties for treating cardiovascular disease. However, stented arteries encounter accelerated rates of restenosis. No prior platform has allowed evaluation or local management of in-stent restenosis without perturbing the very system being examined. A stainless steel, balloon-expandable stent was modified to serve as an ablumenal drug delivery platform. Several combinations of bioerodible polymer microspheres and gels were evaluated for channel retention under in vitro flow and in vivo conditions. A stent-anchored hybrid system prevented material embolization under all conditions. Unlike prior platforms, these stents do not alter local inflammation or in-stent plaque formation relative to conventional Palmaz-Schatz stents after in vivo deployment. The system also proved sensitive enough to detect plaque reduction with an antirestenotic agent. We conclude that a platform to evaluate and deliver therapeutic agents for in-stent restenosis has been achieved.

Intraarterial low-dose cisplatin via an indwelling port and concurrent radiotherapy for invasive bladder cancer

Thirteen patients with invasive bladder cancer who had residual tumor after transurethral resections, were treated with consecutive intraarterial (IA) cisplatin (15 mg/d; total, 150 mg) and concurrent radiation (1.8 Gy/d; total, 30.6 Gy). All patients received unilateral or bilateral placement of vascular access devices (VAD) to perform daily cisplatin infusion after alteration of intrapelvic blood flow by coil embolizations. Tumor response was evaluated by transurethral biopsy 2 weeks after treatment. Complete response, defined as no viable tumor cell in the biopsy specimen, was achieved in seven patients (54%). After a median follow-up of 30 months (range, 12-48 months), 10 patients (77%) were alive, five (38%) of whom had no recurrence. Two cancer-related deaths were observed. All complete response cases survived with a median follow-up of 35 months (range, 25-48 months). Cause-specific and disease-free survival rates at 4 years were 85% and 28%, respectively. The regimen was well-tolerated, with no dose-limiting toxic events. There were no VAD-related complications. Consecutive IA low-dose cisplatin and concurrent radiation may be an acceptable alternative treatment for patients with bladder cancer who are not suitable for systemic chemotherapy. The use of a VAD contributed to successful consecutive IA infusions.

Vascular access system for continuous arterial infusion of a protease inhibitor in acute necrotizing pancreatitis

We used a vascular access system (VAS) for continuous arterial infusion (CAI) of a protease inhibitor in two patients with acute necrotizing pancreatitis. The infusion catheter was placed into the dorsal pancreatic artery in the first patient and into the gastroduodenal artery in the second, via a femoral artery approach. An implantable port was then connected to the catheter and was secured in a subcutaneous pocket prepared in the right lower abdomen. No complications related to the VAS were encountered. This system provided safe and uncontaminated vascular access for successful CAI for acute pancreatitis.

Transvenous Doppler guidewire sonographic monitoring during treatment of a complex vertebral arteriovenous fistula associated with neurofibromatosis type 1

A Doppler sonographic guidewire was used to monitor incremental changes in draining vein (DV) flow during endovascular occlusion of a complex vertebral arteriovenous fistula (AVF) in a patient with neurofibromatosis type 1. Transvenous monitoring of average peak velocity (APV) and the maximum-minus-minimum peak velocity (MxPV-MnPV) demonstrated a progression from a highly pulsatile, fast flow before embolization to a nonpulsatile, slow flow indicating a successful occlusion of the AVF (hemodynamic endpoint of treatment). Prior to this, apparent angiographic occlusion of the AVF was thought to signify a successful endpoint; however, persistently elevated values for APV and MxPV-MnPV in the DV signalled the presence of an additional contralateral arterial contribution. Transvenous monitoring of flow velocity appears to be ideally suited to establishing a hemodynamic endpoint of embolotherapy in the presence of complex arteriovenous shunting, as may occur with the vasculopathy of neurofibromatosis.

[Usefulness of CO2 US angiography in treating hepatocellular carcinoma]

We evaluated the usefulness of CO2 US angiography in the detectability of and the effectiveness of TAE and/or PEIT for hepatocellular carcinoma (HCC). Twenty-three patients with HCC underwent CO2 angiography during the interventional procedure to treat HCC after examination of CT and conventional US. CO2 US angiography was observed on the US monitor by injecting CO2 microbubbles through a catheter placed in the hepatic artery. Contrast materials for CO2 US angiography were 3 ml of CO2 microbubbles prepared by vigorously mixing 3 ml of normal saline with 3 ml of 20% Intralipid, 3 ml of 20% albumin or 3 ml of the patient's own blood. In all patients, CO2 US angiography revealed equal or superior tumor detectability as compared with CT, conventional US and angiography. For demonstrating the inner structure of HCC, the image of CO2 microbubbles mixed with Intralipid was better than that of CO2 microbubbles mixed with albumin. In 9 of 23 patients, CO2 US angiography depicted nodules that had not been seen in the other images. TAE was performed in 21 patients with HCC who showed hypervascularity. In one patient in whom it was difficult to clearly depict the small lesion of HCC by conventional angiography and US, PEIT was successful under CO2 US angiography. The detectability of HCC was higher in CO2 US angiography than in CT, conventional US or angiography. The distribution of blood supply to HCC was observed easily by CO2 US angiography. In TAE of HCC, CO2 US angiography was useful to determine the dose of embolization materials without having to perform repeated angiography. It was possible to perform PEIT easily for non-detectable tumors without CO2 US angiography. CO2 US angiography was useful to evaluate the stage of HCC and to perform TAE and PEIT.

Transvenous hemodynamic assessment of arteriovenous malformations and fistulas. Preliminary clinical experience in Doppler guidewire monitoring of embolotherapy

BACKGROUND AND PURPOSE

Transvenous monitoring of blood flow through intracranial vascular malformations was performed with an intravascular Doppler guidewire to assess hemodynamic changes during endovascular embolotherapy.

METHODS

Flow velocity was assessed in the intracranial venous sinuses of two patients with arteriovenous malformations and seven patients with dural arteriovenous fistulas. In all cases, the Doppler guidewire was positioned in the dural sinuses coaxially through a 2.1F microcatheter. The Doppler guidewire was then advanced to the site of arteriovenous shunting for sampling of venous average peak velocity (APV) and pulsatility index. In two cases, simultaneous feeding artery flow velocity was monitored by transcranial color-coded duplex sonography.

RESULTS

Before embolotherapy, the flow pattern in the venous sinuses was pulsatile, with a mean (+/-SD) APV of 39.0 +/- 22.5 cm/s. Total or near-total embolization was achieved in six of the nine cases. After embolization, the flow pattern became less pulsatile and the APV was reduced to a mean of 21.2 +/- 14.6 cm/s (P = .0123, one-tailed paired t test). The pulsatility index was used to calculate the maximum minus the minimum peak velocity (MxPV-MnPV). This was reduced from an average of 27.0 +/- 8.7 cm/s to 13.5 +/- 8.3 cm/s after treatment (P = .0456). A parallel reduction in APV of the feeding arteries was observed with embolization.

CONCLUSIONS

Preliminary clinical experience indicates that transvenous assessment of two parameters, APV and MxPV-MnPV, is useful in the hemodynamic evaluation of intracranial arteriovenous shunts. This valuable hemodynamic information may be used for objective and quantitative monitoring during embolotherapy of intracranial vascular malformations.