Arterioureteral fistula and refractory fatal pseudo-aneurysm in a patient receiving kidney transplantation.

Arterioureteral fistula represents a rare yet consequential urological complication characterized by persistent and refractory urinary tract bleeding. Its emergence typically involves aneurysm formation, presenting significant life-threatening implications. Nonetheless, its infrequency contributes to sparse documentation of incidences in post-kidney transplant recipients, thereby fostering numerous uncertainties concerning associated risks. A 67-year-old male patient, afflicted with end-stage renal failure and a history of urinary tract infection, underwent a living donor kidney transplant four months prior. Complications involving intraoperative bleeding necessitated the prolonged placement of a ureteral stent post-surgery. Subsequently, he experienced an abrupt onset of ureteral bleeding accompanied by shock, later diagnosed via contrast-enhanced computed tomography as pseudo-aneurysm formation in the right external iliac artery proximal to the allograft renal artery anastomosis, in conjunction with a fistula formation involving the donor ureter. Despite repeated attempts at intervention with covered stenting, the aneurysm persisted and proved refractory to resolution. Tragically, seven months later, the aneurysm ruptured, culminating in the demise of the patient. Our report details a case involving perioperative complications following kidney transplantation, persistent bacteriuria, and prolonged ureteral stenting, ultimately leading to the development of an arterioureteral fistula. Despite undergoing stent graft insertion as an intervention, the patient succumbed to aneurysm rupture associated with the arterioureteral fistula. This condition, though rare, can prove fatal following kidney transplantation. Consequently, future endeavors in this domain necessitate an emphasis on optimizing risk management, refining diagnostic approaches, and devising more effective therapeutic strategies to mitigate such complications.

Detection of Hyperdense Arterial Sign in Acute Ischemic Stroke with Dual-Energy Computed Tomography: Optimal Combination with X-ray Energy and Slice Thickness.

BACKGROUND: The hyperdense artery sign (HAS) in acute ischemic stroke (AIS) is considered an important marker of a thrombus on computed tomography (CT). An advantage of scanning with dual-energy CT (DECT) is its ability to reconstruct CT images with various energies using the virtual monochromatic imaging (VMI) technique. The aim of this study was to investigate the optimal combination of X-ray energy and slice thickness to detect HASs on DECT. METHODS: A total of 32 patients with confirmed occlusion of the horizontal (M1) portion of the middle cerebral artery were included in this study. Modified contrast-to-noise ratio (modified CNR) analysis was used as a method for evaluating HASs in AIS. A region of interest (ROI) was set as an HAS, the M1 portion, and an approximately 2 cm diameter ROI was set as the background including the HAS and measured. CT images with X-ray energies from 40 to 190 keV, with increments of 10 keV, were reconstructed based on VMI with 1, 2, and 3 mm slice thicknesses. RESULTS: The top five combinations of X-ray energy and slice thickness in descending order of the mean HAS-modified CNR were as follows: Rank 1, 60 keV-1 mm; Rank 2, 70 keV-1 mm; Rank 3, 60 keV-2 mm; Rank 4, 80 keV-2 mm; Rank 5, 60 keV-3 mm. CONCLUSIONS: Our study showed that the optimal combination to detect an HAS was 60 keV and a 1 mm slice thickness on DECT.

Diagnosis of a Dural Arteriovenous Fistula Involving the Superior Sagittal Sinus: The MMA Sign on Routine 3D-TOF MR Angiography.

BACKGROUND AND PURPOSE: The main feeding artery of a dural arteriovenous fistula (DAVF) involving the superior sagittal sinus (SSS) is the middle meningeal artery (MMA). MMA extends continuously from the proximal part to SSS in DAVF involving SSS. It is possible to diagnose DAVF involving SSS by evaluating the proximal part of MMA on routine three-dimensional time-of-flight MR angiography (MRA). We termed the finding in an anteroposterior maximum intensity projection (MIP) image of routine MRA in which MMA was continuously visualized at the top of the imaging slab (the upper corpus callosum level) without tapering as the MMA sign. The purpose of the present study was to examine the frequency of the MMA sign on routine MRA in patients with DAVF involving SSS and control patients. MATERIALS AND METHODS: Subjects comprised 18 patients with DAVF involving SSS confirmed by angiography and 871 control subjects who underwent routine MRA. The presence of the MMA sign was retrospectively evaluated using an anteroposterior MIP image of routine MRA in patients with DAVF involving SSS and control patients. RESULTS: The MMA sign was observed in 17 of the 18 (94%) patients with DAVF involving SSS. In one patient with DAVF involving the posterior part of SSS without the MMA sign, the main feeding artery was the occipital artery, not MMA. The MMA sign was observed in 13 of the 871 (1.5%) control patients. CONCLUSION: The MMA sign on routine MRA is useful, suggesting DAVF involving SSS.

Intraoperative Heparin Resistance after Administration of Andexanet Alfa to Manage an Internal Iliac Artery Aneurysm Rupture: A Case Report.

Antithrombotic agents are increasingly prescribed to older adults; however, they are associated with bleeding-related complications. We describe a case of intraoperative heparin resistance after administration of andexanet alfa (AA). An 81-year-old man was diagnosed with a ruptured internal iliac artery aneurysm. The patient required emergency endovascular aneurysm repair and was treated with AA because he was receiving apixaban. Despite high-dose intraoperative heparin administration, his activated coagulation time was not prolonged. Our findings suggest that AA should be administered with caution in patients experiencing potentially fatal bleeding (requiring surgical intervention) who are also receiving direct oral anticoagulants.