Zhiwen Joseph Lo

A Review of Arteriovenous Fistulae Creation in Octogenarians

BACKGROUNDnTo analyze the outcomes of arteriovenous fistulae (AVFs) creation in octogenarians.nnnMETHODSnA retrospective study of 47 AVFs created in patients aged 80xa0years and above from 2008 to 2014. Patient and AVF characteristics and outcomes were evaluated. Predictors of patency were analyzed with multivariate analysis and Kaplan-Meier patency, and survival analysis was performed.nnnRESULTSnForty-seven of 1,259 AVFs created were for octogenarians (4%). Mean age was 83xa0years old (range: 80-91 years), with 27 male (57%) and 35 with tunneled dialysis catheters in situ (75%). There were a total of 15 (32%) radiocephalic AVFs, 30 (64%) brachial-cephalic AVFs, and 2 (4%) brachial-basilic transposition AVFs. At 12xa0months, assisted primary patency rate was 28% (13 patients) while primary failure rate was 72% (34 patients). Subset analysis showed brachial-cephalic AVFs to have the highest assisted primary patency rate at 33%. Within 24xa0months, tunneled dialysis catheter-related sepsis rate was 31% (11 patients). Multivariate analysis did not reveal any factor to be statistically significant in predicting AVF patency. Kaplan-Meier survival curve showed a 50% survival rate at 63xa0months after AVF creation.nnnCONCLUSIONSnIn view of high AVF primary failure rate and relatively low tunneled dialysis catheter bacteremia rate, long-term tunneled dialysis catheters as the main form of hemodialysis renal access may be a viable option. However, with 50% of end-stage renal failure patients surviving up to 63xa0months after AVF creation, the risks and benefits of long-term tunneled dialysis catheters must be balanced against those of AVF creation.

Diabetic foot limb salvage – a series of 809 attempts and predictors for endovascular limb salvage failure

BACKGROUNDnTo review patient characteristics and outcomes of in-patient diabetic foot limb salvage and identify risk factors predicting for endovascular limb salvage failure.nnnMETHODSnRetrospective study of limb salvage attempts in 809 patients between August 2013 and Julyxa02015.nnnRESULTSnSixty-eight percent of our study population were male with mean age at 65 years and 73% presented with Rutherford grade 6 critical limb ischemia, with the remaining 27% Rutherford grade 5. Eighty-one percent had toe pressures of less than 50xa0mm Hg, 64% had infrainguinal trans-Atlantic inter-society consensus (TASC II) C or D lesions while 78% had infrapopliteal TASC II C or D lesions. Seven hundred seventy-seven patients (96%) underwent endovascular-first approach limb salvage, with 95% requiring infrapopliteal angioplasty, with 84% of them requiring 2-vessel or 3-vessel revascularization. Thirty-two patients (4%) underwent surgical bypass limb salvage, with 63% performed as salvage procedures for failed angioplasties. The mean in-patient stay was 12.3xa0days within the endovascular group and 31.1xa0days within the bypass group (Pxa0<xa00.01). One-year limb salvage was successful in 88% of endovascular group, as compared with 72% in bypass group (Pxa0=xa00.01). Overall 1-year survival was 93% within the endovascular group and 88% within the bypass group (Pxa0=xa00.27). The mean in-patient cost was SGD

Predictors of radio-cephalic arteriovenous fistulae patency in an Asian population.

5,518 within the endovascular group and SGD

Outcomes of Central Venoplasty in Haemodialysis Patients

15,141 within the bypass group (Pxa0<xa00.01). Multivariate analysis showed that independent predictors for failure of endovascular limb salvage include end-stage renal failure (ESRF) (odds ratio [OR] 2.04, Pxa0=xa00.01), toe pressures <50xa0mm Hg (OR 2.15, Pxa0=xa00.01), infrainguinal TASC II patterns C or D (OR 1.99, Pxa0=xa00.03), and indirect angiosome revascularization (OR 2.03, Pxa0=xa00.02).nnnCONCLUSIONSnWithin our study population of Asian ethnicity, most in-patient diabetic foot peripheral arterial disease presented with Rutherford grade 6 disease, with mostly TASC II C or D lesions and required infrapopliteal revascularization. As most patients had multiple comorbidities and were poor surgical candidates, the majority underwent endovascular-first approach revascularization. Independent predictors of endovascular limb salvage failure include ESRF, toe pressures <50xa0mm Hg, infrainguinal TASC II patterns C or D, and indirect angiosome revascularization.

Review of Transmetatarsal Amputations in the Management of Peripheral Arterial Disease in an Asian Population

Purpose To identify predictors of arteriovenous fistula (AVF) patency in Asian patients with autogenous radio-cephalic arteriovenous fistula (RCAVF). Methods Retrospective review of 436 RCAVFs created between 2009 and 2013. Predictors of patency were identified with univariate and multivariate analysis. Kaplan-Meier survival analysis and log-rank test were used to calculate patency rates. Results Overall secondary patency rate was 72% at 12 months, 69% at 24 months, 58% at 36 months, 57% at 48 months, 56% at 60 months and 54% at 72 months. Univariate analysis showed that factors which predict for patency include male gender (p = 0.003), good diabetic control (p = 0.025), aspirin use (p = 0.031), pre-dialysis status (p = 0.037), radial artery diameter (p = 0.029) and non-calcified radial arteries (p = 0.002). Age (p = 0.866), cephalic vein diameter (p = 0.630) and surgeon grade (p = 0.472) did not predict for primary AVF failure. Multivariate analysis revealed the male gender to be an independent predictor for patency (odds ratio 1.99, p = 0.01). Subset analysis showed a significantly larger average radial artery diameter of 2.3 mm amongst males, as compared to 1.9 mm amongst females (p = 0.001) and no statistical difference in the average cephalic vein diameter. Conclusions Within our Asian study population, 12-month patency rate of RCAVF is 72%, 69% at 24 months, 58% at 36 months, 57% at 48 months, 56% at 60 months and 54% at 72 months. Male gender is an independent predictor for RCAVF patency. In females or patients with calcified radial arteries, a more proximal AVF should be considered.

Review of Patency Rates between One-Stage and Two-Stage Brachial-Basilic Transposition Arteriovenous Fistulae Creation in an Asian Population

Objective: To review the outcomes of central venoplasty in the treatment of symptomatic central vein stenosis in patients undergoing haemodialysis via an ipsilateral arteriovenous fistula (AVF). Methods: Data were collected retrospectively, and included all the consecutive cases of central venoplasty between January 2008 and December 2015. Results: A total of 132 central venoplasties in 76 patients were performed, with incidence of symptomatic central vein stenosis at 7.4%. Of the patients, 66% were male and the mean age was 61 years. The most frequent indication was decreased dialysis access flow rates (58%) and 52% of all the patients had symptoms of upper limb swelling. The patients who had previous ipsilateral tunneled internal jugular vein dialysis catheters made up 58% of the patients. The mean time from AVF creation to first central venoplasty was 24 months, and 74% of the cases required a second central venoplasty and the mean time to second venoplasty was 7 months. The overall post intervention assisted primary patency rate was 87%, 74%, 63%, and 42% at 6, 12, 18, and 24 months respectively. Statistically significant differences were found in primary assisted patency (p=0.025) and time to second procedure (p=0.039) comparing those with and without a history of ipsilateral tunneled dialysis catheter. Conclusion: Central venoplasty is technically feasible with low procedural risk. The maintenance of the AVF patency usually requires multiple procedures at average interval of 7 months. Patients with a history of upper limb tunneled dialysis catheter ipsilateral to the side of central vein stenosis or AVF have a less favorable outcome compared to those without.

Chimney Stent-Graft Repair for Concurrent Inferior Mesenteric Artery Aneurysm and Infrarenal Abdominal Aortic Aneurysm: Case Report

Objective: To evaluate outcomes after transmetatarsal amputation (TMA) in peripheral arterial disease (PAD) limb salvage in an Asian population and identify risk factors associated with TMA failure. Methodology: A retrospective review of 147 patients with PAD, who had undergone TMA between 2008 and 2014, was carried out. Univariate and multivariate analysis were used to identify predictors of TMA failure. Kaplan–Meier survival analysis was used to calculate major amputation and all-cause mortality rates. Results: The mean age was 66 years. 92% were diabetic patients and 78% had preceded angioplasty. 56% of TMAs were healed via secondary intention, 8% required subsequent split-thickness skin graft closure, 24% required further debridement while 37% had wounds, which failed to heal and required below-knee amputations (BKA). Multivariate analysis showed that diabetes is the only independent predictor of TMA failure (odds ratio (OR) 7.11, p=0.064). Patients with TMA failure were at increased risk of developing nosocomial infections (p=0.025) and faced a higher risk of 30-day re-admission rate (p=0.002). Conclusion: The success rate for PAD limb salvage TMA was 63% and diabetes was an independent predictor of TMA failure. Patients with TMA failure were at increased risks of nosocomial infections, and 30-day re-admissions; hence the risks and benefits of TMA for diabetic foot limb salvage must be individualized for each patient.

A Series of 210 Peripheral Arterial Disease Below-Knee Amputations and Predictors for Subsequent Above-Knee Amputations

Objective: To compare patency rates between one- and two-stage (first-stage arteriovenous anastomosis followed by second-stage superficialization) creation of brachial-basilic transposition arteriovenous fistula (BBT-AVF) in an Asian population. Methods: A retrospective review of BBT-AVFs was conducted between July 2008 and March 2015. Kaplan–Meier survival analysis and log-rank test were used to evaluate patency. Results: In total, 103 BBT-AVFs were created in 86 patients (mean age, 61 years; men, 57%). The overall primary, assisted primary, and secondary patency rates at 12, 24, 36, and 48 months were 70%, 48%, 38%, and 35%; 86%, 70%, 62%, and 59%; and 90%, 77%, 70%, and 63%, respectively. There was no significant difference in demographics and preoperative vessel caliber between the groups. The primary failure rate was 24% in the one-stage group, compared with 21% in the two-stage group (p=0.803). There were no statistically significant differences in primary, assisted primary, and secondary patency rates between the groups. Conclusion: There was no significant difference in primary failure and patency rates between the two groups. Both one-stage and two-stage procedures conferred good outcomes with overall 12-month primary patency, secondary patency, and primary failure rates of 70%, 90%, and 23%, respectively.

Use of Negative Pressure Wound Therapy for Lower Limb Bypass Incisions

PURPOSEnTo report a rare case of concurrent inferior mesenteric artery (IMA) aneurysm and infrarenal abdominal aortic aneurysm (AAA) with a novel indication for the use of chimney stent-graft technique in this patient.nnnCASE REPORTnAn 82-year-old man with an asymptomatic 4.4-cm fusiform AAA and 3.6-cm IMA aneurysm, coupled with chronic occlusion of celiac artery and superior mesenteric artery at the ostia, underwent endovascular repair of both aneurysms. Preservation of the IMA and treatment of both aneurysms were achieved with IMA aneurysm stenting, aortic aneurysm stenting and IMA chimney stenting. At 1, 6, and 12 months surveillance, the grafts remained patent without endoleak.nnnCONCLUSIONSnThe IMA chimney with aortic stenting technique may be safely used in patients who require preservation of the IMA during AAA and IMA aneurysm repairs.

Angio-embolization of a Large Renal Artery Aneurysm: A Case Report and Literature Review

Objective: To review patient characteristics and outcomes after peripheral arterial disease (PAD)-related below-knee amputation (BKA), and identify risk factors predicting subsequent above-knee amputation (AKA). Materials and Methods: A retrospective study of 210 BKAs between May 2008 and December 2015. Results: The mean age of the study population was 66 years. Most of the patients had cardiovascular comorbidities, and 33% had end-stage renal failure (ESRF); 89% were American Society of Anesthesiologists 3 or 4. Previous ipsilateral lower-limb minor amputation was present in 49% and previous contralateral lower-limb major amputation was present in 20% patients. Limb salvage revascularization via angioplasty prior to BKA was performed in 73%, while 27% had extensive tissue loss that was not suitable for limb salvage. Postoperatively, 20% had BKA wound infection, with 3% requiring further surgical debridement, and 9% (19 patients) required subsequent AKA within 1 month. Overall survival analysis at 1–5 years was 75%, 66%, 64%, 59%, and 58%, respectively. Multivariate analysis showed ESRF (Odds Ratio [OR]=3.85; p=0.01) and preoperative non-ambulatory status (OR=5.58; p=0.01) to be independent risk factors in predicting for subsequent AKA. Conclusion: Patients with underlying ESRF or preoperative non-ambulatory status may benefit from direct AKA if major amputation is required.