Hybrid treatment of a thoracoabdominal aortic aneurysm in China: report of the first successful case

Debranching abdominal aortic hybrid surgery for aortic diseases involving the visceral arteries

Objective

Aortic diseases involving branches of the visceral arteries mainly include thoracoabdominal aortic aneurysm (TAAA), aortic dissection (AD) and abdominal aortic aneurysm (AAA). The focus of treatment is to reconstruct the splanchnic arteries and restore blood supply to the organs. Commonly used methods include thoracoabdominal aortic replacement, thoracic endovascular aortic repair and hybrid approaches. Hybrid surgery for aortic disease involving the visceral arteries, consisting of visceral aortic debranching with retrograde revascularization of the celiac trunk and renal arteries and using stent grafts, has been previously described and may be considered particularly appealing in high-risk patients. This study retrospectively analyzed recorded data of patients and contrasted the outcomes with those of a similar group of patients who underwent conventional open repair surgery.

Methods

Between 2019 and 2022, 72 patients (52 men) with an average age of 61.57 ± 8.66 years (range, 36-79 years) underwent one-stage debranching abdominal aortic hybrid surgery. These patients, the hybrid group, underwent preoperative Computed Tomographic Angiography (CTA) and had been diagnosed with aortic disease (aneurysm or dissection) involving the visceral arteries and were at high risk for open repair. The criteria used to define these patients as high-risk group who are in the need of hybrid treatment were American Society of Anesthesiologists (ASA) class 3 or 4. In all cases, we accomplished total visceral aortic debranching through a previous visceral artery retrograde revascularization with synthetic grafts (customized Y or four-bifurcated grafts), and aortic endovascular repair with one of two different commercially produced stent grafts (Medtronic® and Lifetech®). In some cases, we chose to connect the renal artery to the artificial vessel with a stent graft (Viabahn) and partly or totally anastomosed. We analyzed the results and compared the outcomes of the hybrid group with those of a similar group of 46 patients (36 men) with an average age 54.15 ± 12.12 years (range, 32-76). These 46 patients, the conventional open group, were selected for having had thoracoabdominal aortic replacement between 2019 and 2022.

Results

In the hybrid group, 72 visceral bypasses were completed, and endovascular repair was successful in all cases. No intraoperative deaths occurred. Perioperative mortality was 2.78%, and perioperative morbidity was 9.72% (renal insufficiency in 1, unilateral renal infarction in 5, Intestinal ischemia in 1). At 1-month postoperative CTA showed 2 endoleaks, one of which was intervened. At follow-up, there were unplanned reoperation rate of 4.29% and 5 (7.14%) deaths. The remaining patients' grafts were patent at postoperative CTA and no endoleak or stent graft migration had occurred. In the conventional open group, 1 died intraoperatively, 4 died perioperatively, perioperative mortality was 10.87% and complications were respiratory failure in 5, intestinal paralysis/necrosis in 4, renal insufficiency in 17, and paraplegia in 2. At follow-up, 5 (12.20%) patients presented with synthetic grafts hematoma 4 (9.76%) patient died, and 6 (14.63%) patients required unplanned reoperation intervention.

Conclusion

Hybrid surgery is technically feasible in selected cases. For aortic diseases involving the visceral arteries, the application of hybrid abdominal aorta debranching can simplify the operation process, decrease the risks of mortality and morbidity in high-risk and high-age populations and decrease the incidence of various complications while achieving ideal early clinical efficacy. However, a larger series is required for valid statistical comparisons, and longer follow-ups are necessary to evaluate the long-term efficacy of hybrid surgery.

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.

Current status of endovascular treatment for thoracoabdominal aortic aneurysms

Open surgical repair (OSR) for thoracoabdominal aortic aneurysms (TAAAs) is maximally invasive and associated with high rates of operative mortality and perioperative complications including spinal cord ischemia (SCI), despite improvements in surgical techniques and perioperative care. Elderly patients, patients with a history of aortic surgery, and patients with severe comorbidities are often considered ineligible for this surgery and endovascular treatment may be their only treatment option. Total endovascular aneurysm repair (t-EVAR) without debranching surgery does not require thoracotomy and laparotomy and could improve the outcomes of these patients. t-EVAR includes fenestrated EVAR (f-EVAR), multi-branched EVAR (b-EVAR), and physician-modified fenestration endograft (PMFG). Although these techniques have achieved lower mortality rates than OSR, there are concerns about perioperative complications including limb ischemia, SCI, and long-term outcomes such as endograft migration and endoleaks (ELs). This article provides an overview of available endovascular devices for TAAAs and reviews the short and mid-term results of t-EVAR, as well as alternative options.

Hybrid repair for a complex infection aortic pseudoaneurysm with continued antibiotic therapy: A case report and literature review

INTRODUCTION

Treatment of infection aortic pseudoaneurysm (PSA) is a great challenge to surgeons for 3 reasons: high mortality for rupture or threatened rupture; potential risk for infection of prosthetic material which probably bring a devastating result for patients; and long-term antibiotic therapy requirement. Endovascular repair is an alternative to open surgery for a less invasive, which is a trouble procedure for aortic PSA with complex aortic anatomy. The purpose of this article is to report the novel hybrid repair of an infection aortic PSA and antibiotics therapy.

CLINICAL FINDING

A 61-year-old man with complaints of repeated abdominal pain and fever for 3 months was admitted. He had a fever of 39.0°C and normal blood pressure. The blood leukocyte count was 14.9 × 10/L, C-reactive protein was 132 mg/L. There was no evidence for urinary tract infection. The small effusion was identified in bilateral thoracic cavity and pelvis cavity, and the severe lung function impairment was detected. Klebsiella pneumoniae was identified in blood cultures. Computer tomographic (CT) angiography showed a 6 cm × 6 cm aortic PSA involving bilateral renal arteries and a subhepatic inflammatory mass (identified by percutaneous puncture).

DIAGNOSIS

According to the symptoms, CT and lab test, the main diagnosis for this patient were: infective aortic PSA involving bilateral renal arteries, and Bacteremia with K pneumoniae.

INTERVENTION AND OUTCOMES

A hybrid procedure combined open surgical and endovascular was performed for managing the paravisceral infection aortic PSA in a 61-year-old man with high risk. To decrease the risk of graft infection, autologous saphenous vein graft was adopted, and long-term antibiotic therapy was used. At 2 years follow-up, the patient was in good clinical condition with continued antibiotic therapy.

CONCLUSION

Hybrid procedure is an alternative approach according to high risk patients with complex anatomy for open repair of infection aortic PSA. The postoperative long-time continued antibiotic therapy must be emphasized for infection PSA.

Precise plan of hybrid treatment for thoracoabdominal aortic aneurysm: Hemodynamics of retrograde reconstruction visceral arteries from the iliac artery

Hybrid visceral-renal debranching procedures with endovascular repair have been proposed as a less invasive alternative to conventional thoracoabdominal aortic aneurysm or dissection (TAAA or TAAD) surgery. Up to now, there has been no information about the hemodynamic effects of retrograde visceral reconstruction (RVR) for Crawford type II/III/IV TAAA patients undergoing hybrid treatment. The aim is to provide insights in the abnormal hemodynamics of RVR from unilateral or bilateral common iliac arteries (CIAs). Idealized three-dimensional AAs with RVR from unilateral CIA or bilateral CIAs were generated and computationally simulated. The results show that RVRs from CIA lead to a dramatic decrease in flow to the visceral organs compared with a healthy AA and that the anastomosis region is most dangerous to graft occlusion and the initiation of an aneurysm. In addition, compared with a quar-furcated graft, the employment of bilateral bi-furcated grafts have better performance in terms of the wall shear stress (WSS) and flow filed but result in less flow to the celiac and mesenteric arteries. This study has revealed the potential risks after an RVR operation, and points out the advantages and disadvantages of different approaches for the visceral reconstruction, which the vascular surgeons are not fully aware of. According to our results, bilateral bi-furcated grafts are recommended to the TAAA patients when the CIAs are unique inflow sites for visceral reconstruction. A precise plan with patient specific for TAAA or TAAD will be designed for better long-term outcome.

A computational simulation of the effect of hybrid treatment for thoracoabdominal aortic aneurysm on the hemodynamics of abdominal aorta

Hybrid visceral-renal debranching procedures with endovascular repair have been proposed as an appealing technique to treat conventional thoracoabdominal aortic aneurysm (TAAA). This approach, however, still remained controversial because of the non-physiological blood flow direction of its retrograde visceral revascularization (RVR) which is generally constructed from the aortic bifurcation or common iliac artery. The current study carried out the numerical simulation to investigate the effect of RVR on the hemodynamics of abdominal aorta. The results indicated that the inflow sites for the RVR have great impact on the hemodynamic performance. When RVR was from the distal aorta, the perfusion to visceral organs were adequate but the flow flux to the iliac artery significantly decreased and a complex disturbed flow field developed at the distal aorta, which endangered the aorta at high risk of aneurysm development. When RVR was from the right iliac artery, the abdominal aorta was not troubled with low WSS or disturbed flow, but the inadequate perfusion to the visceral organs reached up to 40% and low WSS and flow velocity predominated appeared at the right iliac artery and the grafts, which may result in the stenosis in grafts and aneurysm growth on the host iliac artery.