Experimental multiparametric magnetic resonance imaging characterization of iliocaval venous thrombosis pathological changes.

OBJECTIVE: Iliocaval thrombotic obstruction is a challenging condition, especially because thrombus age and corresponding pathological remodeling at presentation are unknown, which directly impacts management. Our aim was to assess the ability of magnetic resonance imaging (MRI) in determining age thresholds of experimentally created inferior vena cava (IVC) thrombosis in pigs. METHODS: We used a previously described swine model of IVC thrombosis. The animals underwent MRI at baseline, immediately after thrombosis creation, and after a follow-up period extending from 2 to 28 days. Thirteen pigs were divided into three groups according to disease chronicity: acute group (AG; n = 5), subacute group (SAG; n = 4), and chronic group (CG; n = 4), with a mean thrombosis age of 6.4 ± 2.5 days, 15.7 ± 2.8 days, and 28 ± 5.7 days, respectively. A T1-weighted volumetric interpolated breath-hold examination sequence was used to anatomically delineate IVC thrombus as a region of interest. Three other MRI sequences were used to assess the thrombus signal. RESULTS: The Kruskal-Wallis test showed a statistically significant difference in T1 relaxation times after contrast injection (P = .026) between the three groups of chronicity. The AG (360.2 ± 102.5 ms) was significantly different from the CG (336.7 ± 55.2 ms; P = .003), and the SAG (354.1 ± 89.7 ms) was significantly different from the AG (P = .027). There was a statistically significant difference in native T2 relaxation times (P = .038) between the three groups. The AG (160 ± 86.7 ms) was significantly different from the SAG (142.3 ± 55.4 ms; P = .027), and the SAG was significantly different from the CG (178.4 ± 11.7 ms; P = .004). CONCLUSIONS: This study highlighted MRI characteristics in a swine model that might have the potential to significantly differentiate subacute and chronic stages from an acute stage of deep vein thrombosis in humans. Further clinical studies in humans are warranted. CLINICAL RELEVANCE: In addition to providing a better understanding of venous thrombosis remodeling over time, magnetic resonance imaging has the potential to be a tool that could allow us to characterize the composition of venous thrombus over an interval, allowing for a refined analysis of the local evolution of venous thrombosis. We propose a noninvasive and innovative method to characterize different thresholds of chronicity with magnetic resonance imaging features of central deep vein thrombosis of the inferior vena cava experimentally obtained using a totally endovascular in vivo swine model, mimicking human pathophysiology. Being able to determine these features noninvasively is critical for vascular specialists when it comes to choosing between fibrinolytic therapy, percutaneous thrombectomy, or surgical management.

Surgical Treatment of Multiple Venous and Arterial Aneurysms Due to Arteriovenous Malformations of the Arm.

Introduction: Arteriovenous malformations (AVMs) are rare, especially in elderly patients. Occasionally, AVM can produce aneurysmal degenerations, which can lead to bleeding or rupture. The aim of this case report was to describe the surgical treatment of large arterial and venous aneurysms in the arm associated with an AVM. Report: An 83 year old woman of White ethnicity who was a non-smoker presented with a large pulsatile aneurysm at the left elbow with paresis of the first three fingers. The diagnosis was made by duplex ultrasonography (DUS), computed tomography angiography (CTA), and arteriography. Additional tests confirmed aneurysms of the brachial artery and the outflow veins, with the largest more than 7 cm in diameter. A very proximal brachial artery bifurcation and increased venous flow were noted. DUS confirmed the AVM by showing continuous flow in the axillary vein. The decision for surgical resection involved vascular surgeons, radiologists, angiologists, and anaesthetists. Treatment involved opening and excision of multiple venous aneurysms and AVMs. A short segment of the aneurysmal brachial artery was also resected and repaired with end to end anastomosis. The deep brachial artery which supplied AVMs and venous aneurysms was ligated and excision of these lesions was performed. At one year follow up, there were no complications and the revascularisation was patent. Discussion: Arterial and venous aneurysms occurring together with AVMs are rare and not well documented in the medical literature. In this case, surgical intervention, including resection with direct anastomosis of the arterial aneurysm coupled with excision of venous aneurysms and AVM, proved to be effective, as evidenced by stable post-operative outcomes after one year.