Comparison of pharmacological thrombolysis with mechanical thrombectomy in thrombosed arteriovenous fistulas and grafts: a systemic review and meta-analysis.

AIM: To compare the effectiveness and safety of pharmacological thrombolysis and mechanical thrombectomy. MATERIAL AND METHODS: This review was conducted in accordance with the PRISMA guidelines. Pooled proportions and subgroup analysis were calculated for primary and secondary patency rates, technical success, clinical success, major and minor complications rates. RESULTS: This systematic review identified a total of 6,492 studies of which 17 studies were included for analysis. A total of 1,089 patients comprising 451 (41.4 %) and 638 (58.6 %) patients who underwent thrombolysis and mechanical thrombectomy procedures, respectively, were analysed. No significant differences were observed between thrombolysis and mechanical thrombectomy procedures in terms of technical success, clinical success, major and minor complications rates, primary and secondary patency rates; however, subgroup analysis of overall arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) demonstrated a significantly higher rate of major complications within the AVF group (p=0.0248). CONCLUSION: The present meta-analysis suggests that pharmacological thrombolysis and mechanical thrombectomy procedures are similarly effective and safe; however, AVFs are subject to higher major complications compared to AVGs.

Deeper may not be better: relationship between catheter dysfunction and location of the catheter tip in right-sided tunnelled haemodialysis catheters.

AIM: To examine the relationship between catheter tip location and catheter dysfunction in the context of tunnelled central venous catheters (CVCs) for haemodialysis. MATERIALS AND METHODS: This was a retrospective study of 993 haemodialysis patients who underwent insertion of tunnelled CVCs of step-tip design via the right internal jugular vein (IJV). Based on intra-procedural radiographs, the catheter tip was characterised as being in the superior vena cava (SVC), cavo-atrial junction (CAJ), or deep right atrium (DRA). Patients were tracked for 90 days post-procedure for complications resulting in catheter replacement, and these were compared between cohorts. Statistical analysis was performed with Pearson's chi-square and Fisher's exact tests for categorical variables and two-sample t-test and one-way analysis of variance (ANOVA) for continuous variables. RESULTS: Ninety-five patients (9.6%) experienced catheter dysfunction necessitating replacement within 90 days of insertion. Tip location in SVC was associated with lower occurrence of catheter dysfunction (1.9%) as compared with the CAJ (8%) and DRA (11%; p=0.049). Catheter replacement due to other complications (catheter-associated bacteraemia, cuff dislodgement, exit-site infection, external catheter damage) showed no statistically significant relation to location of the CVC tip. CONCLUSION: When utilising tunnelled CVCs with a step-tip design inserted via the right IJV, location of the catheter tip in the SVC is associated with reduced occurrence of catheter dysfunction as compared to either the CAJ or DRA.

Pre-Operative Embolisation of Musculoskeletal Tumours - A Single Centre Experience.

INTRODUCTION: The management of musculoskeletal tumours is complex and requires a multi-disciplinary approach. Preoperative embolisation can be often employed to reduce intra-operative blood loss and complication rates from surgery. We report our experience with the safety, technical success and efficacy of pre-operative embolisation in musculoskeletal tumours. MATERIALS AND METHODS: Thirteen consecutive patients who underwent pre-operative embolisation of a musculoskeletal tumour followed by surgical intervention at our institution from May 2012 to January 2016 were enrolled into the study. Patient demographics, tumour characteristics, embolisation techniques and type of surgery were recorded. Technical success of embolisation, amount of blood loss during surgery and transfusion requirements were estimated. RESULTS: There were five female and eight male patients who underwent pre-operative embolisation during the study period. The age ranged between 16 to 68 years, and the median age was 54. Technical success was achieved in all patients. Mean intra-operative blood loss was 1403ml, with a range of 150ml to 6900ml. Eight patients (62%) required intra-operative blood products of packed red blood cells and fresh frozen plasma. No major complications occurred during embolisation. CONCLUSION: Pre-operative trans-arterial embolisation is feasible and safe for a variety of large and hypervascular musculoskeletal tumours. Our small series suggests that preoperative embolisation could contribute to the reduction of the intra-operative and post-operative blood product transfusion. It should be considered as a pre-operative adjunct for major tumour resections with a high risk of bleeding. The use of the haemoglobin gap complemented the assessment of perioperative blood loss.

Mercury in dental amalgam: Are our health care workers at risk?

Dental amalgam in fillings exposes workers to mercury. The exposure to mercury was investigated among 1871 dental health care workers. The aim of the study was to evaluate the risk of mercury exposure among dental compared to nondental health care workers and to determine other risk factors for mercury exposure. Respondents answered questionnaires to obtain demographic, personal, professional, and workplace information and were examined for their own amalgam fillings. Chronic mercury exposure was assessed through urinary mercury levels. In total, 1409 dental and 462 nondental health care workers participated in the study. Median urine mercury levels for dental and nondental health care workers were 2.75 µg/L (interquartile range [IQR] = 3.0175) and 2.66 µg/L (IQR = 3.04) respectively. For mercury exposure, there were no significant risk factor found among the workers involved within the dental care. The Mann-Whitney test showed that urine mercury levels were significantly different between respondents who eat seafood more than 5 times per week compared to those who eat it less frequently or not at all (p = 0.003). The urinary mercury levels indicated significant difference between dental workers in their practice using squeeze cloths (Mann-Whitney test, p = 0.03). Multiple logistic regression showed that only the usage of cosmetic products that might contain mercury was found to be significantly associated with the urinary mercury levels (odds ratio [OR] = 15.237; CI: 3.612-64.276). Therefore, mean urinary mercury levels of health care workers were low. Exposure to dental amalgam is not associated with high mercury exposure. However, usage of cosmetic products containing mercury and high seafood consumption may lead to the increase of exposure to mercury. IMPLICATIONS: Exposure to the high levels of mercury from dental amalgam can lead to serious health effects among the dental health care workers. Nationwide chronic mercury exposure among dental personnel was assessed through urinary mercury levels. Findings suggest low urinary mercury levels of these health care workers. Exposure to dental amalgam is not associated with high mercury exposure. However, the usage of cosmetic products containing mercury and high seafood consumption may lead to the increase of exposure to mercury.

Heavy fermions. Unconventional Fermi surface in an insulating state.

Insulators occur in more than one guise; a recent finding was a class of topological insulators, which host a conducting surface juxtaposed with an insulating bulk. Here, we report the observation of an unusual insulating state with an electrically insulating bulk that simultaneously yields bulk quantum oscillations with characteristics of an unconventional Fermi liquid. We present quantum oscillation measurements of magnetic torque in high-purity single crystals of the Kondo insulator SmB6, which reveal quantum oscillation frequencies characteristic of a large three-dimensional conduction electron Fermi surface similar to the metallic rare earth hexaborides such as PrB6 and LaB6. The quantum oscillation amplitude strongly increases at low temperatures, appearing strikingly at variance with conventional metallic behavior.

Fragile charge order in the nonsuperconducting ground state of the underdoped high-temperature superconductors.

The normal state in the hole underdoped copper oxide superconductors has proven to be a source of mystery for decades. The measurement of a small Fermi surface by quantum oscillations on suppression of superconductivity by high applied magnetic fields, together with complementary spectroscopic measurements in the hole underdoped copper oxide superconductors, point to a nodal electron pocket from charge order in YBa2Cu3(6+δ). Here, we report quantum oscillation measurements in the closely related stoichiometric material YBa2Cu4O8, which reveals similar Fermi surface properties to YBa2Cu3(6+δ), despite the nonobservation of charge order signatures in the same spectroscopic techniques, such as X-ray diffraction, that revealed signatures of charge order in YBa2Cu3(6+δ). Fermi surface reconstruction in YBa2Cu4O8 is suggested to occur from magnetic field enhancement of charge order that is rendered fragile in zero magnetic fields because of its potential unconventional nature and/or its occurrence as a subsidiary to more robust underlying electronic correlations.

Mutant p53-R273H mediates cancer cell survival and anoikis resistance through AKT-dependent suppression of BCL2-modifying factor (BMF).

p53 is the most frequently mutated tumor-suppressor gene in human cancers. Unlike other tumor-suppressor genes, p53 mutations mainly occur as missense mutations within the DNA-binding domain, leading to the expression of full-length mutant p53 protein. Mutant p53 proteins not only lose their tumor-suppressor function, but may also gain new oncogenic functions and promote tumorigenesis. Here, we showed that silencing of endogenous p53-R273H contact mutant, but not p53-R175H conformational mutant, reduced AKT phosphorylation, induced BCL2-modifying factor (BMF) expression, sensitized BIM dissociation from BCL-XL and induced mitochondria-dependent apoptosis in cancer cells. Importantly, cancer cells harboring endogenous p53-R273H mutant were also found to be inherently resistant to anoikis and lack BMF induction following culture in suspension. Underlying these activities is the ability of p53-R273H mutant to suppress BMF expression that is dependent on constitutively active PI3K/AKT signaling. Collectively, these findings suggest that p53-R273H can specifically drive AKT signaling and suppress BMF expression, resulting in enhanced cell survivability and anoikis resistance. These findings open the possibility that blocking of PI3K/AKT will have therapeutic benefit in mutant p53-R273H expressing cancers.

Superconductivity. Quasiparticle mass enhancement approaching optimal doping in a high-T(c) superconductor.

In the quest for superconductors with higher transition temperatures (T(c)), one emerging motif is that electronic interactions favorable for superconductivity can be enhanced by fluctuations of a broken-symmetry phase. Recent experiments have suggested the existence of the requisite broken-symmetry phase in the high-T(c) cuprates, but the impact of such a phase on the ground-state electronic interactions has remained unclear. We used magnetic fields exceeding 90 tesla to access the underlying metallic state of the cuprate YBa2Cu3O(6+δ) over a wide range of doping, and observed magnetic quantum oscillations that reveal a strong enhancement of the quasiparticle effective mass toward optimal doping. This mass enhancement results from increasing electronic interactions approaching optimal doping, and suggests a quantum critical point at a hole doping of p(crit) ≈ 0.18.

Pilot study evaluating catheter-directed contrast-enhanced ultrasound compared to catheter-directed computed tomography arteriography as adjuncts to digital subtraction angiography to guide transarterial chemoembolization.

AIM: To investigate the feasibility and procedural value of catheter-directed contrast-enhanced ultrasound (CCEUS) compared with catheter-directed computed tomography arteriography (CCTA) in patients undergoing transarterial chemoembolization (TACE) guided by digital subtraction angiography (DSA). MATERIALS AND METHODS: From December 2010 to December 2011, a pilot study was conducted including nine patients (mean age 66.6 years; SD 8.3 years; seven men) undergoing TACE with drug-eluting beads for unresectable hepatocellular carcinoma (HCC). Both CCEUS and CCTA were performed in addition to DSA. Alterations of treatment plan based on CCEUS were recorded and compared with CCTA. RESULTS: CCEUS provided additional information to DSA altering the treatment plan in four out of nine patients (44.4%). In these four patients, CCEUS helped to identify additional tumour feeders (n = 2) or led to a change in catheter position (n = 2). The information provided by CCEUS was similar to that provided by CCTA. CONCLUSION: CCEUS is a potentially valuable imaging tool in adjunction to DSA when performing TACE and may provide similar information to CCTA.

Effective dose estimates for cone beam computed tomography in interventional radiology.

OBJECTIVES: To compare radiation doses in cone beam computed tomography (CBCT) with those of multi-detector computed tomography (MDCT) using manufacturers' standard protocols. METHODS: Dose-levels in head and abdominal imaging were evaluated using a dosimetric phantom. Effective dose estimates were performed by placing thermoluminescent dosimeters in the phantom. Selected protocols for two CBCT systems and comparable protocols for one MDCT system were evaluated. Organ doses were measured and effective doses derived by applying the International Commission on Radiological Protection 2007 tissue weighting factors. RESULTS: Effective doses estimated for the head protocol were 4.4 and 5.4 mSv for the two CBCT systems respectively and 4.3 mSv for MDCT. Eye doses for one CBCT system and MDCT were comparable (173.6 and 148.4 mGy respectively) but significantly higher compared with the second CBCT (44.6 mGy). Two abdominal protocols were evaluated for each system; the effective doses estimated were 15.0 and 18.6 mSv, 25.4 and 37.0 mSv, and 9.8 and 13.5 mSv, respectively, for each of the CBCT and MDCT systems. CONCLUSIONS: The study demonstrated comparable dose-levels for CBCT and MDCT systems in head studies, but higher dose levels for CBCT in abdominal studies. There was a significant difference in eye doses observed between the CBCT systems. KEY POINTS: • Cone beam computed tomography (CBCT) is increasingly utilised in interventional radiology. • Effective doses for selected CBCT and MDCT protocols were estimated and compared. • Dose levels in CBCT and MDCT were comparable for head studies. • Dose levels were higher in CBCT for abdominal studies.

Adjuvant hepatic intra-arterial iodine-131-lipiodol following curative resection of hepatocellular carcinoma: a prospective randomized trial.

BACKGROUND: The purpose of the present study was to determine whether intrahepatic injection of (131)I-lipiodol (Lipiodol) is effective against recurrence of surgically resected hepatocellular carcinoma (HCC). METHODS: From June 2001 through March 2007, this nationwide multi-center prospective randomized controlled trial enrolled 103 patients 4-6 weeks after curative resection of HCC with complete recovery (52: Lipiodol, 51: Control). Follow-up was every 3 months for 1 year, then every 6 months. Primary and secondary endpoints were recurrence-free survival (RFS) and overall survival (OS), respectively, both of which were evaluated by the Kaplan-Meier technique and summarized by the hazard ratio (HR). The design was based on information obtained from a similar trial that had been conducted in Hong Kong. RESULTS: The Lipiodol group showed a small, and nonsignificant, improvement over control in RFS (HR = 0.75; 95 % confidence interval [95 % CI] 0.46-1.23; p = 0.25) and OS (HR = 0.88; 95 % CI 0.51-1.51; p = 0.64). Only two serious adverse events were reported, both with hypothyroidism caused by (131)I-lipiodol and hepatic artery dissection during angiography. CONCLUSIONS: The randomized trial provides insufficient evidence to recommend the routine use of (131)I-lipiodol in these patients.

Computed tomography hepatic arteriography has a hepatic falciform artery detection rate that is much higher than that of digital subtraction angiography and 99mTc-MAA SPECT/CT: implications for planning 90Y radioembolization?

PURPOSE: To compare the hepatic falciform artery (HFA) detection rates of digital subtraction angiography (DSA), computed tomography hepatic arteriography (CTHA) and 99mTc-macroaggregated albumin (99mTc-MAA) single photon emission computed tomography with integrated CT (SPECT/CT) and to correlate HFA patency with complication rates of yttrium-90 (90Y) radioembolization. MATERIAL AND METHODS: From August 2008 to November 2010, 79 patients (range 23-83 years, mean 62.3 years; 67 male) underwent pre-treatment DSA, CTHA and 99mTc-MAA scintigraphy (planar/SPECT/CT) to assess suitability for radioembolization with 90Y resin microspheres. Thirty-seven patients were excluded from the study, because CTHA was performed with a catheter position that did not result in opacification of the liver parenchyma adjacent to the falciform ligament. DSA, CTHA and 99mTc-MAA SPECT/CT images and medical records were retrospectively reviewed. RESULTS: A patent HFA was detected in 22 of 42 patients (52.3%). The HFA detection rates of DSA, CTHA and 99mTc-MAA SPECT/CT were 11.9%, 52.3% and 13.3%, respectively (p<0.0001). An origin from the segment 4 artery was seen in 51.7% of HFAs. Prophylactic HFA coil-embolization prior to 90Y microspheres infusion was performed in 2 patients. Of the patients who underwent radioembolization with a patent HFA, none developed supra-umbilical radiation dermatitis. One patient experienced epigastric pain attributed to post-embolization syndrome and was managed conservatively. CONCLUSION: The HFA detection rate of CTHA is superior to that of DSA and 99mTc-MAA SPECT/CT. Complications related to non-target radiation of the HFA vascular territory rarely occur, even in patients undergoing radioembolization with a patent HFA.

Fluoroscopy-guided, transcervical, selective salpingography and fallopian tube recanalisation.

This study is a retrospective review of the transcervical fluoroscopy-guided fallopian tube recanalisation (FTR) procedures done in a multi-ethnic south-east Asian population, over 9 years. A total of 100 patients with infertility and documented proximal tubal obstruction (PTO) were referred for FTR. On-table hysterosalpingography under sedation demonstrated true PTO in 96 patients. At selective-salpingography, the PTO cleared in 16 patients; 78 required FTR and two had fimbrial blockage. The technical success rate of FTR was 86.8% and the post-FTR pregnancy rate was 36.84% at a mean follow-up interval of 12.2 months. There were no major, immediate procedure-related complications. There was an ectopic pregnancy in a single treated patient. Fluoroscopy-guided FTR is a safe treatment option in patients with infertility from PTO, with high technical success rate, low complication rate and increased chances of pregnancy; therefore it should be preferred before attempting more expensive and resource-intensive procedures.

Retrospective analysis of results of treatment for nasopharyngeal carcinoma in Penang General Hospital from 2001-2005.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is one of the commonest cancers encountered in Malaysia. This study aimed to evaluate the treatment outcomes for patients with NPC treated in Penang General Hospital with specific analysis of prognostic clinicopathological features and treatment modalities. MATERIALS AND METHODS: This retrospective study examined NPC patients between 1st January 2001 and 31st December 2005 in Penang General Hospital. Survival analyses were performed using the Kaplan-Meier method and comparisons between groups were made using the log-rank test. Important prognostic factors including patient demographics, tumour and treatment factors were analysed using the Cox proportional hazard model. RESULTS: A total of 285 patients were identified with a median age of 51 years, 72.6% being males. The majority were Chinese (66%) followed by Malays (31.9%). Primary tumour stages (T stages) 3 and 4 were present in 18.6% and 34% of patients respectively, and nodal disease was present in 80.4%. On overall AJCC staging, 29.1% had stage III and 50.2% had stage IV disease. Some 39.6% of patients had WHO type 3 histology and 7.4% had WHO type 1-2 histology with the remainder having NPC with no subtype reported. Concurrent chemo-irradiation was the commonest treatment received by patients (51.9%) followed by radiotherapy alone (41.8%). The 5 year overall survival and cause specific survival were 33.3% and 42.7% respectively. Age group, T stage, N stage and WHO histological subtype were independent prognostic factors for overall survival on multivariate analysis. For cause specific survival they were T stage and N stage. CONCLUSION: The 5 years overall survival rate was 33.3%. This low figure is primarily due to late presentation. Efforts to detect NPC at earlier stages in Malaysia are urgently needed. These should include public education to increase awareness of the prevalence of this highly treatable disease.

Endovascular aortic repair: the experience of two tertiary institutions in Singapore.

INTRODUCTION: Endovascular aortic repair (EVAR) has gained prominence as a means of treating aortic disease, with lower perioperative morbidity and mortality compared to open surgery. This article aimed to describe the experience of two tertiary hospitals in a Southeast Asian population. METHODS: A retrospective review of 100 consecutive patients undergoing EVAR in two hospitals in Singapore was conducted. This included patients undergoing elective as well as emergency repair. RESULTS: The mean duration of follow-up was 31.8 months. The mean aneurysm size was 6.3 cm and the mean length of stay was 12.1 days. 64 percent of the patients were of American Society of Anesthesiologists class III or above. The deployment success was 98 percent. Major complications (acute myocardial infarction, pneumonia, cerebrovascular accidents, renal failure, colonic infarction and spinal cord infarction) occurred in 18 patients. Perioperative mortality occurred in six percent of cases. The endoleak rate was 28 percent. Both patients with colonic infarction had a single patent internal iliac artery post-procedure, and end-stage renal failure. CONCLUSION: Our results are comparable to published experiences in aortic stenting. Our population possibly had a higher incidence of short common iliac arteries. Revascularisation of internal iliac arteries should be considered for patients with end-stage renal failure and a single patent internal iliac artery.

Use of magnetic resonance imaging in evaluation of placental invasion.

AIM: To review and describe the magnetic resonance imaging (MRI) features in patients with suspected placental invasion and correlate the findings with surgery and pathology findings. MATERIALS AND METHODS: A retrospective review was undertaken of the MRI images of seven consecutive patients with ultrasound findings suspicious for placental invasion. Two experienced MRI radiologists, blinded to the pathology and surgery findings, reviewed the MRI. The pathology or surgical findings were used as the reference standard to establish accuracy and concordance with the MRI findings. RESULTS: Three MRI features described in an earlier series were consistently present in the patients with placental invasion: lower uterine bulging, heterogeneous placenta, and dark intraplacental linear bands on T2-weighted images. CONCLUSION: MRI features, which were described in patients with placental invasion in an earlier series, were useful in establishing the presence and depth of placental invasion.

CT appearance of complications related to thoracic endovascular aortic repair (TEVAR): a pictorial essay.

Thoracic endovascular aortic repair (TEVAR) is a recognized treatment for various diseases involving the thoracic aorta. Patients treated with TEVAR require lifelong surveillance for potential complications, with CT being highly utilized in most centres. Endoleak is the most common complication and can be detected using CT. However, other complications such as stent strut perforations and end organ ischemia can also be detected on CT. The purpose of this pictorial essay is to illustrate the CT appearance of post-TEVAR complications encountered in our institution and to highlight their significance.

Self-expanding nitinol stents in recanalisation of long-length superficial femoral artery occlusions in patients with critical limb ischaemia.

INTRODUCTION: This study aims to evaluate our experience with self-expanding nitinol stent- enabled recanalisation of long-length occlusions (30 cm or more) of the superficial femoral artery (SFA). METHODS: 573 patients underwent 842 lower limb interventions from August 2006 to December 2008. A retrospective review of patients undergoing recanalisation of long-length SFA occlusions with self-expanding nitinol stents and an evaluation of their patency and impact on limb salvage, were done. RESULTS: 22 patients (mean age 62.5 years, male: female ratio 11:11) underwent 22 long-length SFA stenting procedures. The spectrum of critical limb ischaemia included rest pain (five), ulcer (six) and gangrene (11). Length of occlusions varied from 30 cm to 45 cm (average length 36.4 cm). Five patients had stents placed through the ipsilateral popliteal artery approach, and the rest had stents placed through the femoral artery approach. All patients were followed up over an average duration of 12 months. One patient died due to associated medical conditions during this period. Six out of 21 (28.6 percent) of the stents thrombosed completely on one year follow-up. Of these, two patients underwent amputation, one patient had a bypass, and the stent in two patients were recanalised with balloon angioplasty. All remaining patent stents showed varying degrees of stenoses at one year. The overall limb salvage rate at one year following stent placement was 81 percent. CONCLUSION: Our experience showed the beneficial result of long-length SFA stent placement with good limb salvage outcome. Repeat interventions may be required to maintain the patency of stents in these patients.

Gadolinium-enhanced magnetic resonance angiography in renal artery stenosis: comparison with digital subtraction angiography.

OBJECTIVES: To evaluate the accuracy of gadolinium-enhanced magnetic resonance angiography in assessing renal artery stenosis compared to catheter digital subtraction angiography. DESIGN: Retrospective study. SETTING: Singapore General Hospital. PATIENTS: Records of patients who underwent magnetic resonance angiography as well as digital subtraction angiography for assessment of renal artery stenosis from January 2003 to December 2005 were reviewed. RESULTS: There were 27 patients (14 male, 13 female) with a mean age of 62 (range, 44-77) years. There were 10 patients with renal transplants; their native renal arteries were not evaluated. Each of the two experienced interventional and body magnetic resonance radiologists, who were blinded to the results, reviewed the digital subtraction angiography and magnetic resonance angiography images respectively. Digital subtraction angiography was used as the standard of reference. A total of 39 renal arteries from these 27 patients were evaluated. One of the arteries was previously stented and could not be assessed with magnetic resonance angiography due to severe artefacts. Of the remaining 38 renal arteries, two were graded as normal, seven as having mild stenosis (<50%), eight as having moderate stenosis (> or =50% but <75%), and 21 as having severe stenosis (> or =75%). Magnetic resonance angiography and digital subtraction angiography were concordant in 89% of the arteries; magnetic resonance angiography overestimated the degree of stenosis in 8% and underestimated it in 3% of them. In the evaluation of clinically significant renal artery stenosis (> or =50%) with magnetic resonance angiography, the overall sensitivity, specificity, positive predictive value, and negative predictive value were 97%, 67%, 90%, and 86% respectively. The sensitivity and specificity of magnetic resonance angiography in transplant renal artery stenosis was 100%. CONCLUSION. Our experience suggested that gadolinium-enhanced magnetic resonance angiography is a sensitive non-invasive modality useful in the assessment of clinically significant renal artery stenosis.