Nanofiber vascular grafts have been shown to create neovessels made of autologous tissue, by in vivo scaffold biodegradation over time. However, many studies on graft materials and biodegradation ...have been conducted in vitro or in small animal models, instead of large animal models, which demonstrate different degradation profiles. In this study, we compared the degradation profiles of nanofiber vascular grafts in a rat model and a sheep model, while controlling for the type of graft material, the duration of implantation, fabrication method, type of circulation (arterial/venous), and type of surgery (interposition graft). We found that there was significantly less remaining scaffold (i.e., faster degradation) in nanofiber vascular grafts implanted in the sheep model compared with the rat model, in both the arterial and the venous circulations, at 6 months postimplantation. In addition, there was more extracellular matrix deposition, more elastin formation, more mature collagen, and no calcification in the sheep model compared with the rat model. In conclusion, studies comparing degradation of vascular grafts in large and small animal models remain limited. For clinical translation of nanofiber vascular grafts, it is important to understand these differences.
Most tissue-engineered arterial grafts are complicated by aneurysmal dilation secondary to insufficient neotissue formation after scaffold degradation. The optimal graft would form an organized ...multilayered structure with a robust extracellular matrix that could withstand arterial pressure. The purpose of the current study was to determine how oversizing a biodegradable arterial scaffold affects long-term neotissue formation. Size-matched (1.0 mm, n = 11) and oversized (1.6 mm, n = 9) electrospun polycaprolactone/chitosan scaffolds were implanted as abdominal aortic interposition grafts in Lewis rats. The mean lumen diameter of the 1.6 mm grafts was initially greater compared with the native vessel, but matched the native aorta by 6 months. In contrast, the 1.0 mm grafts experienced stenosis at 6 and 9 months. Total neotissue area and calponin-positive neotissue area were significantly greater in the 1.6 mm grafts by 6 months and similar to the native aorta. Late-term biomechanical testing was dominated by remaining polymer, but graft oversizing did not adversely affect the biomechanics of the adjacent vessel. Oversizing tissue-engineered arterial grafts may represent a strategy to increase the formation of organized neotissue without thrombosis or adverse remodeling of the adjacent native vessel by harnessing a previously undescribed process of adaptive vascular remodeling.
The low arterial oxygen saturation (SaO
2
) after bidirectional cavopulmonary shunt (BCPS) predicts poor prognosis. The venous oxygen saturation of inferior vena cava (SivcO
2
), as well as the ...pulmonary blood flow/systemic blood flow ratio (
Q
p
/
Q
s
) affects the SaO
2
. The purpose of this study is to determine whether SivcO
2
or
Q
p
/
Q
s
should be increased to achieve better outcomes after BCPS. Forty-eight patients undergoing BCPS were included. Data of patients’ age and body weight, SivcO
2
,
Q
p
/
Q
s
, pulmonary artery (PA) pressure and resistance, PA area index, morphology of ventricle, atrioventricular valve regurgitation, and history of PA plasty were collected. Stepwise multiple logistic regression analyses were used to investigate which of the factors most affected the SaO
2
after BCPS. There was a significant correlation between SivcO
2
and SaO
2
(
r
= 0.771,
P
< 0.00001). There was no strong correlation between
Q
p
/
Q
s
and SaO
2
(
r
= 0.358,
P
< 0.05). Stepwise multiple logistic regression analyses revealed that both SivcO
2
(
r
= 0.49, 95 % confidence interval (CI) 0.37–0.62,
P
< 0.0001) and
Q
p
/
Q
s
(
r
= 11.1, 95 % CI 3.3–18.9,
P
= 0.007) most affected SaO
2
after BCPS. Since the SivcO
2
has a stronger correlation than
Q
p
/
Q
s
with SaO
2
, despite the fact that both raising
Q
p
/
Q
s
and raising cardiac output can increase SaO
2
, raising cardiac output should be considered prior to
Q
p
/
Q
s
to raise the SaO
2
after BCPS.
The purpose of this case report was to discuss the efficacy of The Amplatzer Vascular Plug (AVP) in endovascular aneurysm repair (EVAR) for ruptured aortoiliac aneurysm. A 73-year-old man was ...referred to our institution with a diagnosis of ruptured abdominal aortic aneurysm (rAAA) by CT scan. The CT scan showed an rAAA of 70 mm (Fitzgerald classification 3) and a right common iliac aneurysm of 30 mm. The patient was immediately transferred from the ER to the OR and treated with EVAR in combination with occlusion of the right internal iliac artery (IIA) using AVP. The total procedural time was 138 min. The patient recovered uneventfully after the operation with an ICU stay of 2 days and was discharged 9 days after the onset. EVAR has been recognized as a therapeutic option for rAAA in Japan. However, it is not yet been generally adopted as a first-line therapy for rAAA accompanied with iliac aneurysm because of the necessity to occlude IIA. The conventional method with coils to induce thrombosis of IIA is unsuitable for patients in a critical situation for the time required and the difficulty in precise placement. AVP is a nitinol-based self-expanding cylindrical device that is used for arterial embolization. AVP allows assured embolization of IIA in a shorter procedural time, which is essential in an urgent situation. Although AVP is still under post-market surveillance in Japan and only available in limited institutions, the usage of AVP should be considered as an adjunctive procedure in EVAR for rAAA and may expand the limits of endovascular treatment for rAAA.
A 79-year-old woman presented to our hospital with a complaint of feeling a cold sensation in her right foot. After performing a contrast-enhanced computed tomography angiography, severe stenosis in ...the right persistent sciatic artery (PSA) was identified. However, stenting was considered inadvisable due to compression issues when sitting. Following anticoagulant therapy, the patient's symptoms improved. However, after seventeen months, she experienced recurrent severe pain in her right foot. Catheter angiography revealed occlusions in both the anterior and posterior tibial arteries. To address the issue, we conducted endovascular therapy, followed by a femoro-popliteal artery bypass and ligation of the PSA. Unfortunately, despite these efforts, a below-knee amputation was eventually performed. Limited experience with the PSA and delayed intervention may have led to the need for amputation. Therefore, it is crucial to emphasize the importance of prompt therapeutic intervention following the onset of initial symptoms.
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