Hojong Park

Management of late-onset portal vein complications in pediatric living-donor liver transplantation.

The purpose of this study was to evaluate retrospectively the results of PTA for late‐onset PV complications after pediatric LDLT and to assess whether a meso‐Rex shunt is a viable option for treating restenosis of the PV after PTA in selected cases. Seventy‐five children who underwent adult‐to‐child LDLT were included in this study, and there were six late‐onset PV complications (8.0%). The initial therapeutic approach was PTA, with or without stent: PTA with balloon dilation for three children, PTA with stent placement for one child, and failure to cannulate the occluded PV for two children. A meso‐Rex shunt was performed in the two children after failed PTA: One suffered complete obstruction of the main PV, and the other, restenosis with total thrombosis after PTA with stent. The PTA was a technical and clinical success in four with PV stenosis of the six patients (66.7%), and successful application of a meso‐Rex shunt in the other two children resulted in restoration of PV flow. In conclusion, PTA is a safe and effective procedure for treating late‐onset PV stenosis after pediatric LDLT. However, in growing pediatric recipients with restenosis of the PV after PTA or chronic PV thrombosis, a meso‐Rex shunt may be a better choice for late‐onset PV complications.

Impact of graft composition on the systemic inflammatory response after an elective repair of an abdominal aortic aneurysm

Purpose The present study aimed to evaluate the risk factors and the role of graft material in the development of an acute phase systemic inflammatory response, and the clinical outcome in patients who undergo endovascular aneurysm repair (EVAR) or open surgical repair (OSR) of an abdominal aortic aneurysm (AAA). Methods We retrospectively evaluated the risk factors and the role of graft material in an increased risk of developing systemic inflammatory response syndrome (SIRS), and the clinical outcome in patients who underwent EVAR or OSR of an AAA. Results A total of 308 consecutive patients who underwent AAA repair were included; 178 received EVAR and 130 received OSR. There was no significant difference in the incidence of SIRS between EVAR patients and OSR patients. Regardless of treatment modality, SIRS was observed more frequently in patients treated with woven polyester grafts. Postoperative hospitalization was significantly prolonged in patients that experienced SIRS. In multivariate analyses, the initial white blood cell count (P = 0.001) and the use of woven polyester grafts (P = 0.005) were significantly associated with an increased risk of developing SIRS in patients who underwent EVAR. By contrast, the use of woven polyester grafts was the only factor associated with an increased risk of developing SIRS in patients who underwent OSR, although this was not statistically significant (P = 0.052). Conclusion The current study shows that the graft composition plays a primordial role in the development of SIRS, and it leads to prolonged hospitalization in both EVAR and OSR patients.

Comparison of surgical and endovascular salvage procedures for juxta-anastomotic stenosis in autogenous wrist radiocephalic arteriovenous fistula.

BACKGROUND Although dysfunctional radiocephalic arteriovenous fistulas (RCAVFs) are typically treated surgically, the endovascular approach is also considered suitable. The aim of this retrospective study was to compare the cumulative patency rates following surgical and endovascular salvaging of dysfunctional RCAVFs, and to evaluate whether the maturity of vascular access sites at the time of treatment influenced the outcomes. METHODS A total of 60 patients underwent surgical or endovascular salvage treatment for juxta-anastomotic stenosis of autogenous wrist RCAVFs: 35 patients underwent proximal neo-anastomosis and 25 underwent percutaneous transluminal angioplasty (PTA). RESULTS Clinical and anatomical success rates were, respectively, 100% and 97.1% in the surgery group, and 100% and 96.0% in the angioplasty group (P = 0.81). The post-treatment restenosis rate was higher in the angioplasty group (n = 11, 46.0%) than in the surgery group (n = 8, 22.8%), without reaching statistical significance (P = 0.15). In a Kaplan-Meier analysis, the primary and assisted primary patency rates were significantly higher in the surgery group (P = 0.036 and P = 0.026, respectively), but there was no significant difference in secondary patency rates between the groups (P = 0.52). When stratified by RCAVF maturity at the time of treatment, no significant difference was noted in primary patency rates between the treatment groups. After adjusting for other variables, the relative risk of restenosis was significantly higher in the angioplasty group (hazard ratio 2.56; 95% confidence interval 1.02-6.46; P = 0.046). CONCLUSIONS Post-treatment primary and assisted primary patency rates after proximal neo-anastomosis were significantly higher than after PTA, and RCAVF maturity did not influence the outcomes.

Risk factors for acute kidney injury after radical nephrectomy and inferior vena cava thrombectomy for renal cell carcinoma

OBJECTIVE The objectives of the present study are to estimate the incidence of postoperative acute kidney injury (AKI) after radical nephrectomy with inferior vena cava (IVC) thrombectomy for renal cell carcinoma (RCC) based on the Acute Kidney Injury Network (AKIN) criteria, to investigate the risk factors for postoperative AKI, and to define the association between postoperative AKI and clinical outcome in patients undergoing such a surgery. METHODS We retrospectively analyzed 76 patients (22 women; mean age, 56.9 years; range, 29-83 years) with RCC and IVC thrombus who underwent radical nephrectomy and IVC thrombectomy at our institute between January 2003 and December 2011. Postoperative AKI was diagnosed after surgery based on the AKIN criteria. Logistic regression was used to model the association between preoperative factors and the risk of AKI after surgery. The relationship between postoperative AKI and clinical outcomes, including chronic kidney disease (CKD), mortality, and days in hospital, was investigated. RESULTS Postoperative AKI was diagnosed in 41 patients (53.9%) based on the AKIN criteria (stage 1, n = 34; stage 2, n = 2; and stage 3, n = 5). Multivariate analysis demonstrated an independent association between postoperative AKI and male gender (odds ratio 4.79, 95% confidence interval: 1.13-20.39; P = .034), and IVC clamping time lasting more than 20 minutes (odds ratio 6.60, 95% confidence interval: 1.48-29.42; P = .013). Development of AKI was associated with an increased rate of postoperative CKD (43.9% vs 20.0%; P = .031) and prolonged hospitalization (17.7 vs 12.2 days; P = .047). Only one patient who had postoperative AKI required renal replacement therapy. There was no 30-day mortality during the study period and no difference in mortality between AKI and non-AKI patients (4.9% vs 5.7%; P = .859). CONCLUSIONS The incidence of postoperative AKI in patients with RCC and IVC thrombus was considerable. Intraoperative management seems to influence the risk of AKI after surgery; particularly, the longer the IVC clamping time, the higher the risk of postoperative AKI. Postoperative AKI was associated with postoperative CKD (P = .031), prolonged hospitalization (P = .047), and increased long-term mortality (1 year after surgery).

A Retrospective 10-Year, Single-Institution Study of Carotid Endarterectomy with a Focus on Elderly Patients

Background and Purpose This study evaluated the outcome following surgery for carotid artery stenosis in a single institution during a 10-year period and the relevance of aging to access to surgery. Methods Between January 2001 and December 2010, 649 carotid endarterectomies (CEAs) were performed in 596 patients for internal carotid artery occlusive disease at our institution; 596 patients received unilateral CEAs and 53 patients received bilateral CEAs. Data regarding patient characteristics, comorbidities, stroke, mortality, restenosis, and other surgical complications were obtained from a review of medical records. Since elderly and high-risk patients comprise a significant proportion of the patient group undergoing CEAs, differences in comorbidity and mortality were evaluated according to age when the patients were divided into three age groups: <70 years, 70-79 years, and ≥80 years. Results The mean age of the included patients was 67.5 years, and 88% were men. Symptomatic carotid stenosis was observed in 65.7% of patients. The rate of perioperative stroke and death (within 30 days of the procedure) was 1.84%. The overall mortality rate was higher among patients in the 70-79 years and >80 years age groups than among those in the <70 years age group, but there was no significant difference in stroke-related mortality among these three groups. Conclusions CEA over a 10-year period has yielded acceptable outcomes in terms of stroke and mortality. Therefore, since CEA is a safe and effective strategy, it can be performed in elderly patients with acceptable life expectancy.

Use of cryopreserved cadaveric arterial allograft as a vascular conduit for peripheral arterial graft infection

Major peripheral arterial graft infection is a potentially devastating complication of vascular surgery, associated with significant mortality and high amputation rates. Autologous saphenous veins are considered optimal arterial conduits for lower extremity revascularization in infected fields, but they are often unavailable or unsuitable in these patients. This study describes two patients with major peripheral graft infection, but without available autologous veins, who underwent graft excision and cryopreserved cadaveric arterial allograft reconstruction. Although long-term graft durability is unclear because of gradual deterioration and degeneration, these findings suggest that cadaveric allografts may be good options for patients with major peripheral graft infection.

Transglutaminase type 2 in human abdominal aortic aneurysm is a potential factor in the stabilization of extracellular matrix

OBJECTIVE The aim of this study was to evaluate transglutaminase type 2 (TG2) expression in human abdominal aortic aneurysm (AAA) tissue and to elucidate a potential role of TG2 in AAA formation. TG2, which is a Ca(2+)-dependent cross-linking enzyme, has been proven important for stabilizing the extracellular matrix. However, there is no evidence of the effect of TG2 on AAA formation in a human model. METHODS Aortic wall tissues were obtained during surgery in AAA patients (n = 38) and in patients with aortoiliac occlusive disease (Control; n = 4) in the Asan Medical Center from March 2011 to February 2012. In each AAA patient, the aortic neck (Neck) and maximally dilated portion (Max) of the aneurysm were sampled for analysis. TG2 expression was evaluated using immunohistochemistry and Western blotting. In addition, ex vivo experiments of isolated AAA tissue culture with the TG2 inhibitor cystamine and recombinant human TG2 were performed. RESULTS Among 38 AAA patients, 11 had ruptured (contained or free) AAAs. The mean maximal diameter of AAAs was 6.09 ± 1.46 cm. TG2 expressions of Max were significantly increased compared with those of Control (1.7-fold increase of Control; P = .00). Compared with Control, the intensities of tissue necrosis factor-α, matrix metalloproteinase (MMP)-2, MMP-9, and tissue inhibitors of metalloproteinase-2 were significantly upregulated in Max (1.7-fold, 1.5-fold, 1.3-fold, and 1.6-fold increases of Control; P = .00, P = .004, P = .046, and P = .007, respectively). Furthermore, double immunofluorescent staining showed that colocalization of TG2/transforming growth factor-β or TG2/fibronectin was prominent in Max compared with those of Neck or Control. In addition, MMP-2 intensity was upregulated in ruptured AAAs compared with unruptured AAAs, with marginal significance (P = .078). Ex vivo experiments showed that protein expressions of tissue necrosis factor-α, MMP-2, and MMP-9 in cultured AAA tissue were decreased by recombinant human TG2 but were increased by exogenous cystamine. CONCLUSIONS The TG2 expression in the maximally dilated portion of AAAs was enhanced compared with that of nondilated aorta. It is suggested that TG2 has a potential effect in stabilization of extracellular matrix by inhibition of proinflammatory cytokines and MMPs or by interaction with fibronectin and transforming growth factor-β.

Renal autotransplantation in open surgical repair of suprarenal abdominal aortic aneurysm

Although the standard treatment of abdominal aortic aneurysm has shifted from open surgery to endovascular repair, open surgery has remained the standard of care for complex aneurysms involving the visceral arteries and in patients unsuitable for endovascular aneurysm repair. Postoperative renal insufficiency may occur after open surgical repair of suprarenal abdominal aortic aneurysm. Methods of minimizing renal ischemic injury include aortic cross-clamping and renal reconstruction techniques. This report describes the use of renal autotransplantation for renal reconstruction during open surgical repair of a suprarenal abdominal aortic aneurysm. This technique was successful, suggesting its feasibility for open suprarenal abdominal aortic aneurysm repair, minimizing renal ischemic injury and optimizing postoperative renal function.

Impact of a preoperative evaluation on the outcomes of an arteriovenous fistula

Purpose The aim of this study was to determine the possible predictors of primary arteriovenous fistula (AVF) failure and examine the impact of a preoperative evaluation on AVF outcomes. Methods A total of 539 patients who underwent assessment for a suitable site for AVF creation by physical examination alone or additional duplex ultrasound were included in this study. Demographics, patient characteristics, and AVF outcomes were analyzed retrospectively. Results AVF creation was proposed in 469 patients (87.0%) according to physical examination alone (351 patients) or additional duplex ultrasound (118 patients); a prosthetic arteriovenous graft was initially placed in the remaining 70 patients (13.0%). Although the primary failure rate was significantly higher in patients assessed by duplex ultrasound (P = 0.001), ultrasound information changed the clinical plan, increasing AVF use for dialysis, in 92 of the 188 patients (48.9%) with an insufficient physical examination. Female sex and diabetes mellitus were risk factors significantly associated with primary AVF failure. Because of different inclusion criteria and a lack of adjustment for baseline differences, Kaplan-Meier survival analysis showed better AVF outcomes in patients assessed by physical examination alone; an insufficient physical examination was the only risk factor significantly associated with AVF outcomes. Conclusion Routine use of duplex ultrasound is not necessary in chronic kidney disease patients with a satisfactory physical examination. Given that female gender and diabetes mellitus are significantly associated with primary AVF failure, duplex ultrasound could be of particular benefit in these subtypes of patients without a sufficient physical examination.

Clinical outcomes related to the level of clamping in inferior vena cava surgery.

ObjectiveIn most cases of inferior vena cava (IVC) surgery, IVC clamping is required owing to several factors, including renal cell carcinoma with IVC thrombus extension and IVC leiomyosarcoma. Various clinical results were compared following IVC clamping by classifying clamping levels into juxtarenal, infrahepatic, and suprahepatic. In particular, the risk factors of postoperative thrombosis after IVC clamping were assessed comparatively.MethodsEighty-four patients who underwent IVC clamping owing to IVC pathology between 2002 and 2012 were retrospectively reviewed with regard to RBC transfusion, operation time, clamping time, liver and kidney functions, duration of hypotension, blood pressure (BP) drops, pulmonary thromboembolism (PTE), venous thrombosis, ICU stay duration, hospital stay duration, 30-day morbidity, and 30-day mortality. In addition, various clinical results were compared when postoperative thrombosis occurred after IVC clamping.ResultsValues for operation time, clamping time, units of RBC transfused, duration of hypotension, severity of BP drops, use of cardiopulmonary bypass (CPB), aspartate aminotransferase, the use of inotropes, IVC patency, ICU stay, and hospital stay duration were significantly higher in the suprahepatic clamping group than in the other clamping groups. In addition, CPB use and IVC clamping level were significant risk factors for postoperative thrombosis after IVC clamping.ConclusionsAlthough IVC clamping is a prerequisite for IVC surgery, operative durations, units of RBC transfused, and length of hospital stays increase with higher clamping levels. In addition, CPB use and IVC clamping level are significant risk factors for postoperative thrombosis. In IVC surgery with higher clamping levels, prompt hemodynamic support and proper anticoagulation therapy are important.