Aneurysm of a 32-Year-Old Aortorenal Saphenous Vein Bypass Graft

Vein Graft Aneurysm after Aorto-Renal Bypass for Childhood Renovascular Hypertension Due to Fibromuscular Dysplasia

Renovascular hypertension (RVHT) is a major cause of surgically correctable secondary hypertension. Refractory hypertension despite multiple antihypertensive drugs requires angioplasty, surgical revascularization, or even nephrectomy. Herein, we report a pediatric patient who had been treated with angioplasty, nephrectomy, and aortorenal bypass surgery for RVHT due to fibromuscular dysplasia and re-do endoaneurysmal graft replacement for a vein graft aneurysm. This case highlights the various treatment modalities for RVHT and the recurrent nature of the disease with a rare presentation of a vein graft aneurysm after aortorenal bypass.

Longitudinal computational fluid dynamics study of stenosis and aneurysmal degeneration of an aortorenal bypass

Saphenous vein graft (SVG) bypass placement is regarded as the optimal option for renal artery stenosis, which usually causes secondary hypertension and poor renal perfusion. Using computational fluid dynamics, this study aimed to investigate the underlying hemodynamic mechanism of the vein aneurysm and stenosis after aortorenal bypass surgery. Three-dimensional models were reconstructed based on computed tomographic angiography images of a 20-year-old female patient who suffered from uncontrollable hypertension using the image processing package Mimics (Materialise). The morphology and hemodynamic parameters in the healthy state, at initial presentation and at post-operative 9-month and 2-year follow-ups after surgery were analysed. The hemodynamic parameters became normal in the left and right renal arteries after bypass surgery. However, flow separation and stagnation occurred at the post-operative 9-month aorta-vein anastomosis, which caused asymmetrical flow and extremely high wall shear stress (WSS) and WSS gradients at the outflow vein tract, where the stenosis occurred 2 years later. In addition, the graft bending produced an asymmetrical flow pattern downstream. This research revealed that the abnormal hemodynamics, including flow separation and extremely high WSS values and gradients, caused by the retrograde flow of aortorenal bypass may be responsible for the SVG degeneration. In addition, flow asymmetry due to vessel bending is a potential risk factor for SVG aneurysm dilation.

Risk of rupture of an aortorenal vein graft aneurysm after the surgical repair of Takayasu arteritis-induced right renal artery stenosis: A case report and a literature review

INTRODUCTION

Takayasu arteritis (TA) is a chronic and nonspecific inflammatory disease mainly affecting the aorta and its major branches, resulting in the stenosis or occlusion of target arteries. Approximately 50% to 60% of patients with TA likely have renal artery stenosis (RAS), which results in refractory hypertension (HTN) and renal dysfunction. Aortorenal bypass with saphenous vein graft (SVG) is the classical procedure to relieve patients' symptoms. Graft restenosis is the most common complication during long-term follow-up. However, aortorenal vein graft aneurysm (AVGA) is uncommonly reported, and symptomatic or ruptured AVGA that needs reoperation is even rarer. Long-term follow-up results after AVGA reoperation also remain scare. Here, we introduced the long-term result of a symptomatic AVGA under the reoperation of polytetrafluoroethylene (PTFE) graft replacement and provided a literature review of AVGA reoperation after surgical bypass for RAS.

CLINICAL FINDING

An 18-year-old male complained about mild to severe right lumbar pain for 5 days. He underwent right aortorenal bypass with SVG for TA-induced right renal artery stenosis to relieve refractory HTN and renal dysfunction 2 years ago. However, this patient did not proceed with a follow-up after the procedure. Physical examination showed normal vital signs, and an obvious percussion tenderness over the right kidney region was detected. The updated computed tomography angiography (CTA) revealed a right AVGA with a maximum diameter of 26 mm. No restenosis of the proximal and distal anastomoses was detected.

DIAGNOSIS

The patient was diagnosed to have right aortorenal vein graft aneurysm at the risk of rupture and Takayasu arteritis.

INTERVENTIONS

The AVGA was resected with a 6 mm PTFE graft replacement. An end-to-side proximal anastomosis to the orifice of the original anastomosis on the abdominal aorta and an end-to-end distal anastomosis to the distal normal renal artery were made.

OUTCOMES

The patient had an uneventful postoperative clinical course and was discharged from the hospital 5 days after the operation. The 4-year updated CTA revealed no restenosis or aneurysmal degeneration of the prosthetic graft.

CONCLUSION

Symptomatic AVGA that needs reoperation is rare. Prosthetic graft replacement is an effective way to eliminate the risk of potential rupture. A 4-year satisfactory result indicative of a prosthetic graft can be the first choice for aortorenal bypass in RAS without active biological inflammation.