Proximal Arterial Inflow Revascularization Improves Pedal Arch Quality and Its Impact on Ischemic Diabetic Foot Ulcer Healing.

BACKGROUND: Arterial perfusion is a key factor in diabetic foot ulcer (DFU) healing. Although it is associated with pedal arch patency, not all patients are amenable to pedal artery angioplasty. This study aims to determine the impact of angiographic improvement of the pedal arch quality after proximal arterial inflow revascularization (PAIR) and its association with wound healing. METHODS: One hundred and fifty diabetic patients with tissue loss in 163 limbs who had digital subtraction angiography were studied. Cox regression analysis was used to determine independent predictors of wound healing. Wound healing rates in association with pedal arch patency were calculated by Kaplan-Meier analysis. RESULTS: End-stage renal disease, minor amputation, and complete pedal arch patency were significant independent predictors of wound healing following PAIR with hazard ratios for failure: 3.02 (P = 0.008), 0.54 (P = 0.023), and 0.40 (P = 0.039), respectively. The prevalence of complete pedal arches increased by 24.1% with successful intervention (P < 0.001). The overall rates of wound healing at 6, 12, and 24 months were 36%, 64%, and 72%, respectively. The wound healing rate at 1 year in patients with a complete pedal arch was 73% compared to 45% in those with an absent pedal arch (P = 0.017). CONCLUSIONS: PAIR increases complete pedal arch patency, a significant predictor of wound healing in DFU.

Optimal flow volume measurements in forearm versus arm arteriovenous fistulas.

OBJECTIVES: Successful haemodialysis is dependent on optimal arteriovenous (AV) access flow. Although 600 ml/min is frequently quoted as the critical level for functional flow volume (Qa) according to the National Kidney Foundation guideline, this may not be applicable for the different configurations of AV fistulas (AVF) or AV grafts (AVG). This study evaluates ultrasound derived Qa measurement in the inflow brachial artery to autologous AVF in the forearm radiocephalic and arm brachiocephalic/basilic configurations in relation to significant flow related AV dysfunction. METHODS: Five hundred and eleven duplex ultrasound (DUS) scans were analysed in 193 patients. The end points were therapeutic intervention and/or thrombosis of AVF versus no complication within 3 months of the scan. Receiver operating characteristic (ROC) curves were used to determine the optimal threshold Qa of the brachial artery supplying the AVF. RESULTS: Of the 511 scans, 155 scans were assigned to the intervention group, that is, AVF requiring intervention or thrombosing within 3 months of the DUS. Using ROC curve analysis, the area under the curve (AUC) for all AVF is 0.90 (CI: 0.88-0.93) with an optimal threshold Qa of 686 ml/min. In forearm AVF, the threshold Qa is 589 ml/min while in arm AVF the threshold Qa is 877 ml/min. Forearm Qa is statistically different from arm Qa. CONCLUSION: Forearm AVF Qa threshold at 589 ml/min is distinct from arm AVF Qa at 877 ml/min and these are predictive of the need for impending intervention or thrombosis due to flow-limiting stenosis.

Receiver operating characteristic curve analysis of arteriovenous dialysis access flow using ultrasound.

BACKGROUNDS: Despite numerous studies investigating the use of ultrasound (US) in assessing arteriovenous fistulas (AVF), there are no universally agreed threshold flow velocities in diagnosing significantly abnormal flow that are useful in predicting thrombotic flow-related dysfunction. This study evaluates a predictive model using receiver operating characteristic curve (ROC) analyses to establish threshold velocities. METHODS: Five hundred and eleven US scans were analysed. ROC curves were used to determine the optimal threshold time average mean velocity (TAMV), peak systolic velocity (PSV) and end diastolic velocity (EDV) of the brachial artery supplying the AVF in determining the need for intervention or thrombosis within 3 months of the scans. Estimated flow volume (FV) ROC was used as an evaluative comparison. RESULTS: There were 356 negative and 155 positive scan results in relation to the need for intervention or thrombosis. Empirical flow velocity parameters of TAMV, EDV and PSV were analysed using ROC curves, yielding an area under the curve (AUC) of 0.95, 0.92 and 0.86, respectively. FV ROC analysis yields a comparative AUC of 0.90. A TAMV cut-off at 48.6 cm/s yielded the highest AUC. Subgroup analysis yielded an optimal TAMV cut-off of 45 cm/s for forearm and 49 cm/s for arm AVF. The EDV was also highly predictive of outcomes. PSV has the lowest accuracy. CONCLUSION: The TAMV of inflow brachial artery to AVF is highly predictive of outcomes of thrombotic flow-related dysfunction. Our study confirms TAMV cut-offs of 45 cm/s for forearm and 49 cm/s for arm AVF. These results require prospective validation.

Inferiority of arteriovenous grafts, in comparison to autogenous fistulas, is underestimated by standard survival measures alone.

BACKGROUND: It has been argued that a prosthetic arteriovenous graft (AVG) is a reasonable alternative to an arteriovenous fistula (AVF) for dialysis. We aimed to compare the patency rates and requirements for the intervention of newly formed AVF and AVG. METHODS: A retrospective analysis was undertaken of AVF and AVG formed between 1 January 2013 and 31 December 2015 at two tertiary referral centres and followed up until 31 December 2017. Outcome measures included successful use for dialysis, patency rates and the number of interventions required to maintain dialysis access per patient-year (PPY). RESULTS: Four hundred and seventy AVF and 92 AVG were constructed. Of 470 AVF, 324 (68.9%) were used compared to 80 of 92 (87%) AVG. One year assisted primary patency of AVF was 75% (confidence interval 71-79%) compared to 47% (confidence interval 36-57%) for AVG. Secondary patency rates for AVF at 1, 2 and 3 years were 77%, 71% and 69%, respectively. At the same time points, secondary patency rates for AVG were 77%, 60% and 46%, respectively (log rank P = 0.034). AVG required 2.4 times the number of interventions PPY than AVF. Surgical thrombectomy of AVG was at a rate of 0.49 PPY compared with 0.042 PPY for AVF. CONCLUSION: AVG have a substantially higher rate of thrombosis than AVF, evident from early in the life of the graft. AVF demonstrate superior patency rates to AVG throughout the life of the access, with far fewer interventions PPY than grafts.

Giant cell arteritis presenting as critical lower limb ischemia.

A 62-year-old woman presented with ischemic pain of her lower limb on 2 occasions, without upper limb or cranial vessel involvement. She was treated with open bypass of her left lower limb when she presented with critical limb ischemia during her second admission. Although bilateral temporal artery biopsies were negative, superficial femoral artery biopsy at the time of surgery confirmed the diagnosis of giant cell arteritis. Corticosteroid therapy was promptly commenced.

Excellent outcomes of simultaneous pancreas kidney transplantation in patients from rural and urban Australia: a national service experience.

BACKGROUND: Simultaneous pancreas and kidney (SPK) transplantation is performed to restore normoglycemia and renal function in patients with type 1 diabetes mellitus and end-stage renal failure. The National Pancreas Transplant Unit (NPTU) in Sydney provides a service to a population spread across 7.4 million km. We aimed to see if SPK transplantation outcomes differed between recipients from metropolitan (M) centers and those from nonmetropolitan (NM) regions. METHODS: Using a prospectively collected database, patient and graft survival were analyzed. Patients were categorized according to region of residence and by distance from the NPTU. RESULTS: Between January 2001 and May 2010, 165 patients underwent first-time SPK transplantation at the NPTU. There were 126 M and 39 NM recipients. Median distance from the NPTU was 732 km for donors (range, 0-3930 km) and 887 km for recipients (range, 1-4114 km). Median follow-up was 5.2 years (range, 1.1-10.3 years). Actuarial 5-year patient survival was 94% in M and 95% in NM groups. At 5 years, non-death-censored pancreas graft survival was 75% and 82% among M and NM patients, respectively, while kidney allograft survival was 88% in M and 92% in NM groups. There was no significant difference in patient and graft survival between groups. Distance of donor and recipient from the NPTU did not influence graft or patient survival. CONCLUSIONS: SPK transplantation can be performed with excellent outcomes at a national center with a vast catchment area, irrespective of donor or recipient location.

Central vein stenosis in an Asian hemodialysis population.

OBJECTIVE AND BACKGROUND: Central vein stenosis occurs commonly after instrumentation of the major thoracic veins. We aimed to investigate factors that contributed to this condition in an Asian hemodialysis population, and the results of intervention. PATIENTS AND METHODS: Hemodialysis patients diagnosed with central vein stenosis between January 2003 and December 2008, were identified from the records of the National University Hospital, Singapore. Eligible controls had a minimum of 2 years of hemodialysis via an arteriovenous fistula and/or central venous catheter, without clinical or radiological evidence of central vein stenosis. RESULTS: Central vein stenosis was diagnosed in 108 patients. The most common presenting features were arm swelling (32%) and failed hemodialysis catheter insertion (28%). The median frequency of permanent hemodialysis catheter insertion in those who subsequently developed venous stenosis (1.44 per patient per year) was 4 times that of controls (0.36 per patient per year; p<0.001). Ischemic heart disease (p = 0.03) and in certain patients, arteriovenous fistula surgery were associated with the development of central vein stenosis; whereas line sepsis, diabetes, and hypertension were not. Central vein angioplasty was attempted in 53 patients; the primary patency was 52% at 1 year. CONCLUSION: Central vein stenosis is associated with a higher frequency of hemodialysis catheter insertion and access surgery. Efforts to decrease permanent hemodialysis catheter use should reduce the incidence of central vein stenosis.

Outcomes of initial hemodialysis access surgery in an Asian population.

PURPOSE: Access-related morbidity contributes substantially to the costs of hemodialysis. The aim of this study was to examine the outcomes of initial hemodialysis access surgery at a single center in Singapore and to analyze factors which might influence survival of the surgically-created access. METHODS: Patients undergoing their first hemodialysis access operations between January 2003 and December 2007 were retrospectively identified. Primary and assisted primary patency rates were determined by the Kaplan-Meier method. Data on age, sex, diabetic status, and prior tunneled central venous catheter (CVC) use were analyzed against the outcome of arteriovenous fistulas (AVF). RESULTS: During the study period, 410 primary upper limb access operations were performed: 297 forearm AVF (72.4%), 91 upper arm AVF (22.2%), and 22 arteriovenous grafts (AVG; 5.4%). Men comprised 55.4%, 271 (66.1%) had diabetes, and 316 patients (77.1%) came to surgery with pre-existing CVC. Sixty-two percent of forearm AVF and 67% of arm AVF were used successfully. Age, sex, diabetes, and prior use of a CVC did not significantly affect the ability to use an AVF. Only in the female diabetic subgroup was an earlier loss of primary assisted patency of AVF recorded. CONCLUSIONS: In our Asian population, we have demonstrated AVF patency rates equivalent to those of international centers. We now face the challenge of achieving a higher rate of pre-emptive AVF placement with a subsequent reduction in CVC use.

Ruptured thoracoabdominal aneurysm in a 27-year-old with hyper IgE syndrome.

Hyperimmunoglobulin E syndrome is a rare primary immunodeficiency disorder defined by high serum immunoglobulin E titers and associated with characteristic infectious, dermatologic, skeletal, and dental abnormalities. We present the case of a 27-year-old man presenting acutely with a ruptured type IV thoracoabdominal aortic aneurysm. He was successfully treated by open operative repair and discharged with long-term prophylactic antibiotics. To our knowledge, this is the first such case reported in the English literature.