Treatment of popliteal artery aneurysms by means of cryopreserved homograft

Ten-year experience with use of cryopreserved allografts for redo infrapopliteal bypass

INTRODUCTION

The aim of this study is to report the early and late outcomes of cryopreserved saphenous vein (CSV) in redo infrainguinal bypass and to investigate possible predictors of primary patency loss.

METHODS

All patients who underwent a redo bypass for critical limb ischemia from January 2010 to December 2020 were reviewed. Early and late complications were analyzed and included. The endpoints of the study were all cause mortality, major limb amputation, and primary patency (PP).

RESULTS

Data were collected from 95 patients. Among the entire cohort, 16 (16.8%) patients received a cryopreserved vessel bypass with anastomosis in the popliteal artery and 79 (83.2%) patients had cryopreserved vessel bypasses with distal anastomosis in tibial vessels. Median duration of follow-up was 73 months; during this, period estimated survival at 5 years was 80.5 ± 4% (95% CI, 78.0-91.2) and estimates of freedom from limb amputation was 90.3 ± 3.2% (95% CI, 87.3-98.1). Overall, the estimated primary patency of the bypass was 43.7 ± 6.7% (95% CI, 30.2-51.4). On multivariable analysis, intraprocedural tibial vessel angioplasty (HR = 2.3, p = 0.01), distal anastomosis in tibial vessels (HR = 3.6, p = 0.36), and the use of a composite graft (HR = 2.4, p = 0.01) were independently associated with loss of PP.

CONCLUSIONS

The use of CSV in redo bypass is an effective strategy in salvaging threatened lower extremities and in preventing or delaying limb amputation. Our results confirm that further attempts at revascularization are generally appropriate, even in technically changing patients.

Evaluation of Arterial and Venous Allografts in Subinguinal Bypasses

BACKGROUND

Autologous saphenous vein is the preferred conduit for below-the-knee bypasses in patients with critical limb-threatening ischemia. Alternative graft must be considered for patients without (autologous saphenous vein). The aim of this article is to evaluate the mid-term performance of arterial allograft (AA) and venous allograft (VA) used as alternative conduits.

METHODS

This retrospective study included patients with critical limb-threatening ischemia, with or without a history of homolateral femoropopliteal bypass, and no autologous veins were available who underwent infrainguinal arterial reconstructions using VA or AA from 2008 to 2018. Patients undergoing revision operations for infected bypasses were excluded. Primary patency (PP), primary assisted patency, secondary patency, major amputation, and death from any cause were the endpoints. For each event, a set of analyses were performed.

RESULTS

Overall, 111 patients (63 VAs and 48 AAs) were included, with 108 having below-the-knee bypass. The median follow-up time was 27.8 months (15.6-37.4). The difference in PP between the 2 allograft types was significant (P = 0.049), with 65.9% (43.7-81.0), 44.1% (24.2-62.3), and 44.1% (24.2-62.3) in the AA group, respectively, at 6, 12, and 18 months, whereas 55.6% (40.0-68.6), 46.0% (30.6-60.2), and 33.2% (18.2-49.0) in the VA group. The choice of an AA over a VA was an independent factor associated with patency (for PP: hazard ratio [HR] = 0.43 [0.24-0.75], P = 0.003); primary assisted patency: HR = 0.52 (0.30-0.89], P = 0.018; and secondary patency: HR = 0.49 (0.27-0.88), P = 0.016. The allograft type did not affect either the incidence of major amputation or death from any cause (respectively, HR = 1.20 [0.49-2.93], and 0.88 [0.37-2.14]).

CONCLUSIONS

The nature of the allograft appears to influence the patency of infrainguinal reconstruction, but not the course of the disease. Performant alternative grafts answering infectious issues are needed.

Potentials of Using Allografts in Surgical Treatment of Popliteal Artery Aneurysms

BACKGROUND: The gold standard in reconstructive surgical operations on the infrainguinal arteries is the autovenous conduit from the great saphenous vein. However, in the absence of a suitable autovein, difficulties are encountered in the selection of a suitable material for reconstruction. The use of a synthetic prosthesis as an alternative in the knee joint region is not always possible, especially in the distal position. Unsatisfactory results of using such materials dictate the need to choose a suitable graft. The paper describes two case experiences of using allografts from a deceased donor for the surgical treatment of popliteal artery aneurysms. The cases present their potential for use in emergency clinical situations. In the first case, the patient had previously undergone phlebectomy. In the second case, the saphenous veins of the lower limbs had scattered branches and insufficient diameter for reconstruction. CONCLUSION: The described cases presented the possible effective use of allografts from a deceased donor in patients with true popliteal artery aneurysms.

Ex Vivo and In Vivo Analysis of a Novel Porcine Aortic Patch for Vascular Reconstruction

(1) Background: The aim of the present study was the biocompatibility analysis of a novel xenogeneic vascular graft material (PAP) based on native collagen won from porcine aorta using the subcutaneous implantation model up to 120 days post implantationem. As a control, an already commercially available collagen-based vessel graft (XenoSure®) based on bovine pericardium was used. Another focus was to analyze the (ultra-) structure and the purification effort. (2) Methods: Established methodologies such as the histological material analysis and the conduct of the subcutaneous implantation model in Wistar rats were applied. Moreover, established methods combining histological, immunohistochemical, and histomorphometrical procedures were applied to analyze the tissue reactions to the vessel graft materials, including the induction of pro- and anti-inflammatory macrophages to test the immune response. (3) Results: The results showed that the PAP implants induced a special cellular infiltration and host tissue integration based on its three different parts based on the different layers of the donor tissue. Thereby, these material parts induced a vascularization pattern that branches to all parts of the graft and altogether a balanced immune tissue reaction in contrast to the control material. (4) Conclusions: PAP implants seemed to be advantageous in many aspects: (i) cellular infiltration and host tissue integration, (ii) vascularization pattern that branches to all parts of the graft, and (iii) balanced immune tissue reaction that can result in less scar tissue and enhanced integrative healing patterns. Moreover, the unique trans-implant vascularization can provide unprecedented anti-infection properties that can avoid material-related bacterial infections.

Investigation of a method for long-term preservation of the vascular allograft

BACKGROUND/OBJECTIVE

During multiple organ procurement, blood vessels are routinely retrieved and stored in University of Wisconsin solution and then discarded after two weeks, if not used at organ transplantation owing to lack of a method for long-term preservation. Therefore, the aim of this study is to investigate a method for long-term preservation of vascular allografts in ethanol.

METHODS

Aorta and vena cava allografts were retrieved and stored in 75% ethanol solution for 12 months at 4°C. Four pigs were divided into two groups. A segment of aorta was excised and replaced by insertion of preserved aorta graft (Group A) or vena cava graft (Group V). The pigs were observed for six weeks. A laparotomy was performed and the vascular graft was harvested for histopathology followed by euthanasia at the end of study.

RESULTS

Three pigs recovered uneventfully, while one pig died from venous graft rupture in the third week after surgery. There was no aneurysmal formation or thrombosis in the grafts. Some calcification was seen over aorta allograft. On histopathology, the elastic pattern was almost normal, although the endothelial cells degenerated after preservation. After implantation, the formation of the endothelium cell-like layer was seen in both aorta and vena cava allografts.

CONCLUSION

Vascular allografts were functional after preservation for 12 months. The vena cava grafts had much less wall calcification than the aorta grafts. Further studies are necessary to investigate vascular graft remodelling with a longer observation period after implantation.

Surgical Treatment of Symptomatic Aortic Aneurysm in a Patient with Anti-neutrophil Cytoplasmic Antibody-associated Vasculitis: Case Report and Review of the Literature

Vasculitis is an heterogeneous group of syndromes, which shares inflammation of blood vessel wall as the main feature. Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a necrotizing vasculitis, with few or no immune deposits, predominantly affecting small vessels (i.e., capillaries, venules, arterioles, and small arteries), associated with ANCAs specific for myeloperoxidase or proteinase 3. Clinical manifestations may be heterogeneous but an involvement of lungs and kidneys frequently occurs. AAV of large vessels is a very rare condition whose standard therapy is medical approach. Surgical revascularization has been described in selected patients after medical failure or in emergent settings. We report the case of a patient affected by symptomatic infrarenal aortic aneurysm related to AAV, who underwent in-situ reconstruction by means of cryopreserved homograft.

Comparison of Endovascular Versus Bypass Surgery in Femoropopliteal TASC II D Lesions: A Single-Center Study

BACKGROUND

In patients with severe occlusive disease (Trans-Atlantic Inter-Society Consensus II D [TASC II D]) of the femoropopliteal segment, the advantages of endovascular versus bypass revascularization still remain debated. Most reports available in literature comparing percutaneous transluminal angioplasty (PTA) ± bare metal stent (BMS) versus synthetic bypass analyze patients with heterogeneous anatomical lesions creating possible bias when results of different treatments are matched. In this study, we compared early and midterm outcomes of PTA ± BMS versus heparin-bonded expanded polytetrafluoroethylene graft (Propaten-Gore) + Linton patch in patient affected by symptomatic femoropopliteal TASC II-D lesions.

METHODS

Eighty limbs with symptomatic severe occlusive disease (TASC II D) of the femoropopliteal segment observed from January 2013 to January 2017 were included in this retrospective study. Indication to treatment was severe claudication in 17 limbs (21.2%) and critical limb ischemia (CLI) in 63 (78.8%). 36.2% of limbs presented at least 2 distal patent vessels, and 63.8% had only 1 patent vessel. Of these limbs, 40 were treated by means of PTA ± BMS (group A), and 40 were treated by means of femoropopliteal bypass with Propaten-Gore graft + Linton patch (group B). Patients were followed with a clinical assessment and duplex at 1, 6, and 12 months after procedure and then annually. A closer follow-up was performed in case of any complication. Patency, reintervention rate, and limb salvage were compared in the 2 groups.

RESULTS

The mean length of arterial occlusion was 22.1 cm (range, 8-37) in group A versus 25.2 cm (range, 9-41) in group B, P = ns. A slight difference in mean procedural time was observed (83.5 min of group A versus 114 min of group B, minutes, P = 0.02). Mean follow-up was 26.7 months (range, 3-46). Primary patency at 6, 12, and 24 months of group A versus group B was 76.9% vs. 97.5% (P = 0.007), 65.7% vs. 89.1% (P = 0.05), and 52.6% vs. 78.1% (P = 0.005), respectively. Assisted primary patency was 76.9% vs. 97.5% (P = 0.007), 68.5% vs. 91.8% (P = 0.02), and 57.8% vs. 87.5% (P = 0.001), respectively. Secondary patency was 94.8% vs. 97.5% (P = ns), 85.7% vs. 97.2% (P = ns), 73.6% vs. 93.7% (P = 0.004), respectively. Rate of reintervention at 24 months was 45% in group A vs. 20% in group B (P = 0.03). Limb salvage rate at 24 months was 90% for group A vs. 92.5% for group B (P = ns). Univariate analysis showed CLI and poor runoff to be independent risk factors for significant restenosis/occlusion of target artery and reintervention.

CONCLUSIONS

In patients with severe femoropopliteal occlusive disease (TASC II D), the surgical revascularization by means of Propaten-Gore bypass + Linton patch can be considered safe and effective. Early and midterm results of this approach seem to be superior to PTA ± BMS in terms of restenosis/occlusion and reintervention rates. Larger cohort and longer term results are mandatory to better define this advantage.

A Strange "Collection" after Surgery for an Aneurysm of the Popliteal Artery

The popliteal fossa is the site of several diseases that may be similar in the clinical setting but very different in etiology, treatment, and prognosis. The contemporary presentation of more than one of these conditions is a rare though potentially fatal combination that may lead to a delay in the diagnosis and therapeutic approach. In this report, we describe the case of a patient who presented at our Vascular Department for persistent pain and severe swelling of the right popliteal fossa 8 months after the surgical treatment of a symptomatic popliteal aneurysm by mean of a Dacron prosthetic graft. With the suspect of the graft infection, as defined by angio-computer tomography and fluorodeoxyglucose positron emission tomography, the patient underwent graft removal and revascularization with a biologic conduit. Subsequent surgical revisions for unjustified recurrent hematic collections were necessary without any significative clinical improvement. The histologic analysis of the removed tissue was consistent with a high-grade sarcoma, and the patient underwent above-the-knee amputation of the right limb.