Do thrombotic events during endovascular interventions lead to poorer outcomes in patients with severe limb ischemia?

INTRODUCTION: Intra-procedural acute thrombosis (IPAT) is a complication of endovascular procedures. We aim to identify risk factors for IPAT and compare the outcomes of patients with or without IPAT. METHODS: Paired T test and χ (2) test were used to identify risk factors and short-term outcomes. Kaplan-Meier survival analysis was used for mid-term outcomes. RESULTS: A total of 228 procedures were performed with 21 IPAT events (9.21%). The odds ratio of Indian patients developing IPAT was 2.8x (95% CI 1.1-7.6). Patients with in-stent occlusion or prior IPAT were 5.6x (95% CI 1.3-24.2) and 5.6x (95% CI 1.3-24.4) more likely to develop an IPAT event. Patients without IPAT had significantly more improvement in mean runoff score (-1.15 ± 1.31, p < 0.01). The odds of patients with IPAT requiring subsequent endovascular intervention and arterial bypass surgery were 4.2x (95% CI 1.6-10.7) and 7.1x (95% CI 1.9-27.0). There was no significant Kaplan-Meier estimated overall survival or amputation-free survival difference between patients with or without IPAT event. CONCLUSION: Indian ethnicity, in-stent occlusion and previous IPAT were associated with higher risk of IPAT. Even after successful endovascular salvage, patients with IPATs were more likely to require secondary revascularization procedure. Patients with IPATs had no decrease in overall survival or amputation-free survival.

Comparative outcomes of primary autogenous fistulas in elderly, multiethnic Asian hemodialysis patients.

BACKGROUND: The number of elderly (≥65 years) end-stage renal disease (ESRD) patients on hemodialysis is rapidly increasing. Vascular access outcomes remain contradictory and understudied across different elderly populations. We hypothesized age might influence primary autogenous fistula use and outcomes in a predominantly diabetic multiethnic Asian ESRD population. METHODS: Demographic and clinical factors affecting fistula patency and maturation were retrospectively compared among patients with incident ESRD aged <65 and ≥65 years at a single center. Fistula patency was estimated by Kaplan-Meier curves with log-rank test comparison. RESULTS: We analyzed 280 primary fistulas (59% radiocephalic, 33% brachiocephalic, and 8% brachiobasilic) in this cohort consisting of 31.8% aged ≥65 years, 50% Chinese, 39% Malay, 42% women, and 70% diabetic. One- and 2-year primary and secondary patency in patients aged <65 vs ≥65 years were comparable: 41.3% vs 36.7% and 28.7% vs 24.4% (P = .547) and 57.7% vs 56.8% and 47.1% vs 47.2% (P = .990). On multivariate analysis, only non-Chinese, dialysis initiation with tunneled catheters, and surgical/endovascular interventions affected fistula survival hazard ratios (HR): 0.622 (95% confidence interval [CI], 0.43-1.00), 0.549 (95% CI, 0.297-0.841), and 2.503 (95% CI, 1.695-3.697), respectively. Nonmaturation and intervention rates were also similar at 56.7% vs 61.8% and 34% vs 32.2% at 3 and 6 months and 0.31 vs 0.36 per access year, respectively (P > .05). Females and tunneled catheters were the only risk factors for nonmaturation (HR, 1.568; 95% CI, 1.148-1.608, and HR, 1.623; 95% CI, 1.400-1.881, respectively). CONCLUSIONS: A primary fistula strategy in incident elderly ESRD is feasible and does not result in inferior outcomes. Age should therefore not be a determinant for primary fistula creation.

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.

Does the introduction of a third examiner and global marking improve the generalisability of the surgical long case?

INTRODUCTION: Planning a high-stake clinical examination requires the evaluation of several psychometric and logistical variables. The authors conducted generalisability and decision studies to answer the following research questions in the context of the surgical long case: (1) Does the addition of a third examiner have any added benefit, vis-à-vis reliability, to the examination? (2) Is global marking more reliable than an itemised marking template? (3) What would be the impact on reliability if there was a reduction in the number of examinees that each panel of examiners is required to assess? METHODS: A third examiner and global marking were introduced. Separate generalisability and decision studies were carried out for both the two- and three-examiner models as well as for itemised and global scores. RESULTS: The introduction of a third examiner resulted in a modest gain of reliability by 0.05-0.07. Gain in reliability was higher when each candidate was allowed to undertake a higher number of clinical cases. Both the global and itemised scores provided equivalent reliability (generalisability coefficient 0.74-0.89). CONCLUSION: Our results showed that only a modest improvement in reliability of the surgical long case is achieved through the introduction of an additional examiner. Although the reliability of global scoring and the itemised marking template was comparable, the latter may provide opportunities for individualised feedback to examinees.

Outcomes of endovascular intervention for salvage of failing hemodialysis access.

OBJECTIVE: To investigate the effectiveness of endovascular balloon angioplasty to preserve the patency of failing hemodialysis arteriovenous fistulas (AVF) and prosthetic arteriovenous grafts (AVG). METHODS: Patients on hemodialysis who received endovascular intervention for access problems were retrospectively analyzed. Fistulography was performed on patients who were suspected to have access stenosis and balloon angioplasty performed in the same setting if a stenosis of ≥50% is detected. Patients were followed up for post-operative complications and access restenosis or failure. RESULTS: 42 hemodialysis patients with 44 access sites (29 AVFs, 15 AVGs) required endovascular balloon angioplasty. There were no perioperative complications. Technical success rate was 100%. Median time from initial access creation to first balloon angioplasty was 13 months (2-146 months) for AVFs and 8 months (2-71 months) for AVGs. 19 of 44 patients subsequently developed restenosis. Median time for restenosis or access failure was 11 months (1-18 months) for AVFs and 5 months (1-10 months) for AVGs. Kaplan-Meier analysis for access patency after endovascular intervention showed 72% patency at 6 months and 32% at 12 months. CONCLUSIONS: Endovascular balloon angioplasty is effective in restoring patency of failing hemodialysis accesses. Recurrence is common, and repeat interventions are required.

Late relapse of non-typhoidal salmonella vascular graft infection after 5 years.

Salmonella bacteremia can be complicated by mycotic aneurysm with the potential for a catastrophic presentation. Treatment involves prompt surgery with debridement, extraanatomic bypass, and prolonged antibiotic therapy. Any relapse tends to occur within the 1(st) year after surgery. We describe a case of Salmonella enteritidis mycotic aneurysm in a 56-year-old man 5 years after the initial presentation, emphasizing the importance of aggressive initial therapy and long-term surveillance.

Chronic brainstem ischemia in subclavian steal syndrome.

Subclavian steal syndrome is usually an incidental finding and rarely causes vertebrobasilar ischemia. We present a 58-year-old man who, over six months, experienced progressive slowing in both talking and walking. Cervical duplex sonography revealed severe stenosis of the right subclavian artery; fixed retrograde flow was noted in the right vertebral artery on transcranial Doppler. The hyperemia-ischemia cuff test resulted in considerable reduction in flow velocities in both posterior cerebral arteries. We attributed his slowness to chronic vertebrobasilar ischemia and surgical revascularization was performed. His symptoms subsided immediately after surgery. The improved perfusion in the posterior circulation was demonstrated on technetium-99 hexamethylpropyleneamine oxime single photon-emission CT. Early diagnosis and prompt treatment resulted in an improved quality of life.