We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The ... more We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The patient was a 32-year-old man who presented with a short history of throat discomfort and a choking sensation. Laryngoscopy identified bulging of the posterior pharyngeal wall that partially occluded the laryngeal inlet. A lateral neck x-ray revealed that the prevertebral space was widened, and computed tomography detected fluid in the retropharyngeal and parapharyngeal spaces. Neck exploration revealed that the edema had been caused by nonsuppurative fluid. Biochemical analyses revealed marked hypoalbuminemia and heavy proteinuria suggestive of nephrotic syndrome. Following surgery, the patient's symptoms resolved. Aseptic effusion into the retropharyngeal space is rare; reported etiologies include internal jugular vein thrombosis, neoplasia, radiation therapy, trauma, acute calcific tendinitis, hereditary angioedema, and myxedema of hypothyroidism. To the best of our knowledge, this is the first case of nephrotic syndrome initially manifesting as retropharyngeal pseudoabscess to be reported in the literature. Thrombotic occlusion of the pharyngeal venous plexus secondary to hypercoagulability is a plausible explanation for such isolated retropharyngeal effusion.
Introduction: Carbon monoxide poisoning (COP) is one of the leading causes of death from poisonin... more Introduction: Carbon monoxide poisoning (COP) is one of the leading causes of death from poisoning worldwide. There is no published study of COP in Singapore so far. Materials and methods: All patients admitted with the diagnosis of COP to Tan Tock Seng Hospital (TTSH) over 5 years from 1999 to 2003 were retrospectively reviewed. The diagnosis was based on a history of potential exposure to carbon monoxide (CO) and elevated levels of carboxyhaemoglobin (COHb). The causes, demographic data, clinical presentations, management and complications were analysed. Results: There were 12 patients with COP. Their average age was 38.9 (+/-11.8) years, with a male-to-female ratio of 3:1. Accidental COP (58.3%) was more common than intentional COP (41.7%). The most common cause of accidental COP was smoke inhalation from a faulty vehicle. Gas stove was the most preferred source for intentional poisoning. Presenting features were headache (83.3%), confusion (83.3%), coma (12.7%) and agitation (8.3%). The mean COHb level on admission was 35.9% (+/-13.6). All were treated with 100% oxygen. All the patients achieved normal levels of COHb within 24 hours of admission. Two (16.7%) required intubation for airway protection as they were comatose on arrival, of which 1 presented with very high level of COHb (48.1%) and was the only patient to be treated with hyperbaric oxygen. Acute complications were globus pallidus infarction (16.6%), acute respiratory distress syndrome (8.3%) and myocardial ischaemia (8.3%). Most of the patients (91.7%) were discharged well from the hospital. One patient developed parkinsonism after a follow-up of 2 years. There were no deaths. Conclusion: COP is relatively uncommon in Singapore. It has a low rate of short- and long-term complications.
Background: Patients having bariatric surgery are at moderate-to-high risk for post-operative ven... more Background: Patients having bariatric surgery are at moderate-to-high risk for post-operative venous thromboembolism (VTE), with pulmonary embolism representing the most common cause of post-operative death. The optimal dosing and duration of anticoagulant prophylaxis is uncertain. Aim: To evaluate the efficacy and safety of extended-duration, weight-adjusted tinzaparin for post-operative thromboprophylaxis after bariatric surgery. Methods: Retrospective cohort of 793 bariatric surgery patients who received routine post-operative weight-adjusted tinzaparin, 4,500-14,000 IU daily (75 IU/kg, rounded to the nearest pre-filled syringe) for 7 days after hospital discharge. The primary efficacy and safety outcomes were the frequency of VTE and major bleeding, respectively, within 30 days of surgery in patients receiving at least 1 dose of tinzaparin. Results: 793 patients who underwent bariatric surgery from 2009 to 2012 were reviewed. There were 44 (5.5%) patients excluded from analyses: need for therapeutic-dose anticoagulation (n=16); no post-operative tinzaparin (n=27); surgery aborted (n=1). There were 646 and 645 patients included in the 30-day efficacy and safety analyses, respectively (mean age, 44.6 years [SD 9.7], median body mass index, 47.1 kg/m2 [range: 19.4-81.0]). An additional 106 patients had outcome data only during hospital admission. VTE occurred in 1/645 patients (0.3%; pulmonary embolism) after hospital discharge and in 1/752 patients (0.1%; superior mesenteric vein thrombosis) in hospital. Major bleeding occurred in 12/645 patients (1.9%). Trough anti-Xa levels measured 7-10 days post-operatively were undetectable in 143/190 (75.3%) patients. In the other 47 patients the median trough anti-Xa level was 0.12 IU (range: 0.10-0.41). Conclusions: Weight-adjusted, extended-duration tinzaparin appears effective and safe for post-operative thromboprophylaxis after bariatric surgery. There was no drug accumulation with large doses of tinzaparin. Disclosures Siegal: Interactive Forums Inc.: Other: created educational slides; Daiichi Sankyo: Other: participated in an advisory board; Boerhinger Ingelheim: Other: participated in an advisory board; Portola Pharmaceuticals: Other: participated in an advisory board. Douketis:Bayer: Consultancy; Actelion: Consultancy; Biotie: Other: Advisory board; Sanofi-Aventis: Honoraria; The Medicines Company: Other: Advisory board; Janssen: Consultancy; Daiichi-Sankyo: Consultancy; Bristol-Myers Squibb: Consultancy, Honoraria; Pfizer: Honoraria; Boehringer Ingelheim: Consultancy, Honoraria.
Annals Academy of Medicine Singapore, Nov 15, 2013
Introduction: Novel oral anticoagulants (NOACs) have at least equivalent effi cacy compared to st... more Introduction: Novel oral anticoagulants (NOACs) have at least equivalent effi cacy compared to standard anticoagulants with similar bleeding risk. Optimal management strategies for bleeding complications associated with NOACs are currently unestablished. Materials and Methods: A working group comprising haematologists and vascular medicine specialists representing the major institutions in Singapore was convened to produce this consensus recommendation. A Medline and EMBASE search was conducted for articles related to the 3 available NOACs (dabigatran, rivaroxaban, apixaban), bleeding and its management. Additional information was obtained from the product monographs and bibliographic search of articles identifi ed. Results: The NOACs still has substantial interactions with a number of drugs for which concomitant administration should best be avoided. As they are renally excreted, albeit to different degrees, NOACs should not be prescribed to patients with creatinine clearance of <30 mLs/min. Meticulous consideration of risk versus benefi ts should be exercised before starting a patient on a NOAC. In patients presenting with bleeding, risk stratifi cation of the severity of bleeding as well as identifi cation of the source of bleeding should be performed. In life-threatening bleeds, recombinant activated factor VIIa and prothrombin complex may be considered although their effectiveness is currently unsupported by fi rm clinical evidence. The NOACs have varying effect on the prothrombin time and activated partial thromboplastin time which has to be interpreted with caution. Routine monitoring of drug level is not usually required. Conclusion: NOACs are an important advancement in antithrombotic management and careful patient selection and monitoring will permit optimisation of their potential and limit bleeding events.
Journal of Thrombosis and Haemostasis, Oct 1, 2018
Essentials • The optimal dose and duration of thromboprophylaxis after bariatric surgery are uncl... more Essentials • The optimal dose and duration of thromboprophylaxis after bariatric surgery are unclear. • We evaluated the safety of weight-adjusted tinzaparin prophylaxis in 1212 patients. • In-hospital rates of venous thromboembolism and major bleeding were 0.2% and 1.8% respectively. • In a subset of patients, trough anti-Xa levels did not show excessive anticoagulant activity. Summary. Background: Patients undergoing bariatric surgery are at moderate to high risk of venous thromboembolism (VTE). The optimal dose and duration of anticoagulant prophylaxis is uncertain. Objective: To evaluate the safety of extended-duration weight-adjusted tinzaparin after bariatric surgery. Patients/methods: We conducted a single-center retrospective cohort study of consecutive patients undergoing bariatric surgery who received weight-adjusted tinzaparin 4500-14 000 IU daily (75 IU kg À1 rounded to the nearest prefilled syringe) for 10 days after surgery (7-9 days post-hospital discharge). Primary safety outcomes were the frequency of VTE and major bleeding within 30 days of surgery in patients receiving at least one dose of tinzaparin. Results: A total of 1279 patients undergoing bariatric surgery between July 2009 and December 2012 were reviewed, of whom 1212 received weight-adjusted tinzaparin. Safety outcomes were collected for 819 patients at 30 days, and for 1212 patients in-hospital only. The median age was 45.0 years, median weight was 130.0 kg and 98.8% of patients underwent gastric bypass or sleeve gastrectomy. In patients completing 30 days of follow-up, VTE occurred in 4/819 (0.5%) and major bleeding occurred in 13/819 patients (1.6%). In-hospital rates of VTE and major bleeding during surgical admission were 3/1212 (0.2%) and 22/1212 (1.8%), respectively. Conclusions: Extended thromboprophylaxis with weight-adjusted tinzaparin appears to be a safe strategy after bariatric surgery, with low rates of postoperative VTE and major bleeding.
ObJeCTIve: To study the response of systolic and diastolic blood pressure (BP) and renal function... more ObJeCTIve: To study the response of systolic and diastolic blood pressure (BP) and renal function after renal artery stenting at three months, six months, one year and last follow-up. MeTHODS: Patients with significant renal artery stenosis who underwent angioplasty with stenting from January 1999 to September 2006 were analyzed. The BP and serum creatinine levels were recorded at baseline, three months, six months, one year and at last follow-up. Generalized estimating equations were applied to analyze the changes in blood pressure and serum creatinine over time. ReSulTS: There were 32 patients-21 Chinese, six Malay and five Indian. The male to female ratio was 1.3:1. The mean age (± SD) was 69.4±8.8 years. The mean follow-up time was 1.8±1.6 years (range 0.5 to six years). When compared with the baseline BP, there was significant improvement at three months, six months, one year and at last follow-up. In the diabetes mellitus (DM) group, there was deterioration in serum creatinine. In the non-DM group, there was stabilization of serum creatinine with improvement at one year. COnCluSIOn: Significant improvement in BP occurs in renal artery stenosis patients after stenting. In patients without DM, renal function remains stable or improves. However, in DM patients, especially those with proteinuria, there is deterioration in renal function.
Widening of the pre-vertebral space on a lateral neck radiograph is an indication of retropharyng... more Widening of the pre-vertebral space on a lateral neck radiograph is an indication of retropharyngeal abscess. Non infective isolated effusion in retropharyngeal space is rare. This article describes a case of nephrotic syndrome manifesting as retropharyngeal pseudoabscess.
Background: Stroke is a major cause of death and disability globally, especially in particular in... more Background: Stroke is a major cause of death and disability globally, especially in particular in the Asia-Pacific region, which is home to more than 4 billion people. Among the modifiable risk factors for stroke, hypertension is the strongest, but controllable to confer large outcome benefits. Objective: To investigate the association between hypertension and stroke burden in Asia-Pacific countries. Design and Methods: Stroke burden, as defined as age- and sex-standardised disability-adjusted life-years lost (DALYs) per 100,000 persons attributed to stroke, in Asia Pacific countries was extracted from the Global Burden of Disease (GBD) Study 2010. The age- and sex-standardised prevalence (%) of hypertension, defined as systolic blood pressure > 140 mmHg and diastolic blood pressure > 90 mmHg among adults aged 18 years or older, in these same countries was obtained from the World Health Organisation (WHO) database for 2015. Linear correlation was then estimated by calculating ...
Essentials • The optimal dose and duration of thromboprophylaxis after bariatric surgery are uncl... more Essentials • The optimal dose and duration of thromboprophylaxis after bariatric surgery are unclear. • We evaluated the safety of weight-adjusted tinzaparin prophylaxis in 1212 patients. • In-hospital rates of venous thromboembolism and major bleeding were 0.2% and 1.8% respectively. • In a subset of patients, trough anti-Xa levels did not show excessive anticoagulant activity. Summary. Background: Patients undergoing bariatric surgery are at moderate to high risk of venous thromboembolism (VTE). The optimal dose and duration of anticoagulant prophylaxis is uncertain. Objective: To evaluate the safety of extended-duration weight-adjusted tinzaparin after bariatric surgery. Patients/methods: We conducted a single-center retrospective cohort study of consecutive patients undergoing bariatric surgery who received weight-adjusted tinzaparin 4500-14 000 IU daily (75 IU kg À1 rounded to the nearest prefilled syringe) for 10 days after surgery (7-9 days post-hospital discharge). Primary safety outcomes were the frequency of VTE and major bleeding within 30 days of surgery in patients receiving at least one dose of tinzaparin. Results: A total of 1279 patients undergoing bariatric surgery between July 2009 and December 2012 were reviewed, of whom 1212 received weight-adjusted tinzaparin. Safety outcomes were collected for 819 patients at 30 days, and for 1212 patients in-hospital only. The median age was 45.0 years, median weight was 130.0 kg and 98.8% of patients underwent gastric bypass or sleeve gastrectomy. In patients completing 30 days of follow-up, VTE occurred in 4/819 (0.5%) and major bleeding occurred in 13/819 patients (1.6%). In-hospital rates of VTE and major bleeding during surgical admission were 3/1212 (0.2%) and 22/1212 (1.8%), respectively. Conclusions: Extended thromboprophylaxis with weight-adjusted tinzaparin appears to be a safe strategy after bariatric surgery, with low rates of postoperative VTE and major bleeding.
INTRODUCTION: Renal angioplasty has been increasingly used to treat significant renal artery sten... more INTRODUCTION: Renal angioplasty has been increasingly used to treat significant renal artery stenosis (RAS). At the Tan Tock Seng Hospital (Singapore), renal angioplasty patients are routinely admitted to the high dependency unit (HDU) postprocedure for monitoring. METHODS: The complications of the RAS patients were reviewed postangioplasty, and it was determined whether the patients could be monitored in the general ward (GW) instead of the HDU. Cases of patients with RAS of more than 50% who underwent angioplasty between January 1999 and September 2006 were reviewed retrospectively. RESULTS: There were 35 patients with significant RAS who underwent angioplasty. Thirty were monitored in the HDU. Five were monitored in the GW because there were no HDU beds available. Patients in the GW were monitored every 30 min for 6 h, then every hour for 24 h. No immediate complications or deaths were recorded in the present series. CONCLUSION: It may be safe and cost-effective to monitor patients with significant RAS postangioplasty in the GW.
Widening of the pre-vertebral space on a lateral neck radiograph is an indication of retropharyng... more Widening of the pre-vertebral space on a lateral neck radiograph is an indication of retropharyngeal abscess. Non infective isolated effusion in retropharyngeal space is rare. This article describes a case of nephrotic syndrome manifesting as retropharyngeal pseudoabscess.
Objective: We evaluate the efficacy of anticoagulant administration for isolated distal deep vein... more Objective: We evaluate the efficacy of anticoagulant administration for isolated distal deep vein thrombus (IDDVT), detected before orthopedic surgery. Materials and Methods: The study included 32 patients diagnosed with IDDVT before orthopedic surgery in our hospital between October 2011 and October 2017. They were divided into two groups: the pre-and post-operative therapy group, who were administered anticoagulants both pre-and post-operatively, and the post-operative therapy group, who were administered anticoagulants only after surgery due to risk of bleeding judged by an orthopedic surgeon. We compared the primary efficacy (change in IDDVT size) between the two groups. Results: The proportion of patients with increased postoperative IDDVT sizes was significantly larger in the post-operatively treated group than in the pre-and post-operatively treated group (44.4% vs. 8.7%, p=0.026). No case demonstrated an IDDVT extension proximal to the popliteal vein or presented with symptomatic pulmonary thromboembolism in this study. Conclusion: Based on our findings, we recommend that, in patients with IDDVT detected prior to orthopedic surgery and administered anticoagulant therapy only after the procedure because of a bleeding risk, a lower limb ultrasonography to re-evaluate the existing deep vein thrombus should be conducted before beginning rehabilitation.
We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The ... more We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The patient was a 32-year-old man who presented with a short history of throat discomfort and a choking sensation. Laryngoscopy identified bulging of the posterior pharyngeal wall that partially occluded the laryngeal inlet. A lateral neck x-ray revealed that the prevertebral space was widened, and computed tomography detected fluid in the retropharyngeal and parapharyngeal spaces. Neck exploration revealed that the edema had been caused by nonsuppurative fluid. Biochemical analyses revealed marked hypoalbuminemia and heavy proteinuria suggestive of nephrotic syndrome. Following surgery, the patient's symptoms resolved. Aseptic effusion into the retropharyngeal space is rare; reported etiologies include internal jugular vein thrombosis, neoplasia, radiation therapy, trauma, acute calcific tendinitis, hereditary angioedema, and myxedema of hypothyroidism. To the best of our knowledge, thi...
To study the response of systolic and diastolic blood pressure (BP) and renal function after rena... more To study the response of systolic and diastolic blood pressure (BP) and renal function after renal artery stenting at three months, six months, one year and last follow-up. Patients with significant renal artery stenosis who underwent angioplasty with stenting from January 1999 to September 2006 were analyzed. The BP and serum creatinine levels were recorded at baseline, three months, six months, one year and at last follow-up. Generalized estimating equations were applied to analyze the changes in blood pressure and serum creatinine over time. There were 32 patients - 21 Chinese, six Malay and five Indian. The male to female ratio was 1.3:1. The mean age (± SD) was 69.4±8.8 years. The mean follow-up time was 1.8±1.6 years (range 0.5 to six years). When compared with the baseline BP, there was significant improvement at three months, six months, one year and at last follow-up. In the diabetes mellitus (DM) group, there was deterioration in serum creatinine. In the non-DM group, ther...
With advances in modern imaging techniques, portal vein thrombosis (PVT) is being increasingly di... more With advances in modern imaging techniques, portal vein thrombosis (PVT) is being increasingly diagnosed. It has a wide ranging clinical spectrum from being an asymptomatic state to a potentially life-threatening situation. It is not unusual to find it as an incidental finding in the abdominal imagings done for other reasons. It is commonly associated with cirrhosis and abdominal malignancies and also has a strong association with prothrombotic disorders. It is often difficult for the clinicians to decide whether PVT is acute or chronic. This poses great challenges to its management strategies that include anticoagulants, thrombolysis, and surgical options. Timely diagnosis and appropriate management have great bearings on its outcomes of morbidity and mortality. In this clinician-oriented review, we have provided a concise review of clinical aspects of PVT and discussed various management strategies while addressing the common questions that come to a physician’s mind dealing with ...
INTRODUCTION Novel oral anticoagulants (NOACs) have at least equivalent efficacy compared to stan... more INTRODUCTION Novel oral anticoagulants (NOACs) have at least equivalent efficacy compared to standard anticoagulants with similar bleeding risk. Optimal management strategies for bleeding complications associated with NOACs are currently unestablished. MATERIALS AND METHODS A working group comprising haematologists and vascular medicine specialists representing the major institutions in Singapore was convened to produce this consensus recommendation. A Medline and EMBASE search was conducted for articles related to the 3 available NOACs (dabigatran, rivaroxaban, apixaban), bleeding and its management. Additional information was obtained from the product monographs and bibliographic search of articles identified. RESULTS The NOACs still has substantial interactions with a number of drugs for which concomitant administration should best be avoided. As they are renally excreted, albeit to different degrees, NOACs should not be prescribed to patients with creatinine clearance of <30 ...
We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The ... more We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The patient was a 32-year-old man who presented with a short history of throat discomfort and a choking sensation. Laryngoscopy identified bulging of the posterior pharyngeal wall that partially occluded the laryngeal inlet. A lateral neck x-ray revealed that the prevertebral space was widened, and computed tomography detected fluid in the retropharyngeal and parapharyngeal spaces. Neck exploration revealed that the edema had been caused by nonsuppurative fluid. Biochemical analyses revealed marked hypoalbuminemia and heavy proteinuria suggestive of nephrotic syndrome. Following surgery, the patient's symptoms resolved. Aseptic effusion into the retropharyngeal space is rare; reported etiologies include internal jugular vein thrombosis, neoplasia, radiation therapy, trauma, acute calcific tendinitis, hereditary angioedema, and myxedema of hypothyroidism. To the best of our knowledge, thi...
Introduction Human immunodeficiency virus (HIV) patients are at risk of developing thrombosis tha... more Introduction Human immunodeficiency virus (HIV) patients are at risk of developing thrombosis than general population. There are several intersecting mechanisms associated with HIV infection and antiviral therapy that are emerging, which may lead to vasculopathy and hypercoagulability in these patients. Methods We analyzed the HIV patients who followed up with our Vascular Medicine outpatient clinic with venous thromboembolism (VTE) over the past 3 years and followed them prospectively. The patients included were those who had minimum, regular follow-up of 3 months, with a Doppler scan in the beginning and last follow-up. Patients were analyzed for age, gender, race, site of thrombosis, coagulation factors, lipid panel, type of antiretroviral treatment, past or present history of infections or malignancy, CD4 absolute and helper cell counts at the beginning of thrombosis, response to treatment and outcome. Patients with HIV with arterial thrombosis were excluded. Results A total of ...
We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The ... more We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The patient was a 32-year-old man who presented with a short history of throat discomfort and a choking sensation. Laryngoscopy identified bulging of the posterior pharyngeal wall that partially occluded the laryngeal inlet. A lateral neck x-ray revealed that the prevertebral space was widened, and computed tomography detected fluid in the retropharyngeal and parapharyngeal spaces. Neck exploration revealed that the edema had been caused by nonsuppurative fluid. Biochemical analyses revealed marked hypoalbuminemia and heavy proteinuria suggestive of nephrotic syndrome. Following surgery, the patient's symptoms resolved. Aseptic effusion into the retropharyngeal space is rare; reported etiologies include internal jugular vein thrombosis, neoplasia, radiation therapy, trauma, acute calcific tendinitis, hereditary angioedema, and myxedema of hypothyroidism. To the best of our knowledge, this is the first case of nephrotic syndrome initially manifesting as retropharyngeal pseudoabscess to be reported in the literature. Thrombotic occlusion of the pharyngeal venous plexus secondary to hypercoagulability is a plausible explanation for such isolated retropharyngeal effusion.
Introduction: Carbon monoxide poisoning (COP) is one of the leading causes of death from poisonin... more Introduction: Carbon monoxide poisoning (COP) is one of the leading causes of death from poisoning worldwide. There is no published study of COP in Singapore so far. Materials and methods: All patients admitted with the diagnosis of COP to Tan Tock Seng Hospital (TTSH) over 5 years from 1999 to 2003 were retrospectively reviewed. The diagnosis was based on a history of potential exposure to carbon monoxide (CO) and elevated levels of carboxyhaemoglobin (COHb). The causes, demographic data, clinical presentations, management and complications were analysed. Results: There were 12 patients with COP. Their average age was 38.9 (+/-11.8) years, with a male-to-female ratio of 3:1. Accidental COP (58.3%) was more common than intentional COP (41.7%). The most common cause of accidental COP was smoke inhalation from a faulty vehicle. Gas stove was the most preferred source for intentional poisoning. Presenting features were headache (83.3%), confusion (83.3%), coma (12.7%) and agitation (8.3%). The mean COHb level on admission was 35.9% (+/-13.6). All were treated with 100% oxygen. All the patients achieved normal levels of COHb within 24 hours of admission. Two (16.7%) required intubation for airway protection as they were comatose on arrival, of which 1 presented with very high level of COHb (48.1%) and was the only patient to be treated with hyperbaric oxygen. Acute complications were globus pallidus infarction (16.6%), acute respiratory distress syndrome (8.3%) and myocardial ischaemia (8.3%). Most of the patients (91.7%) were discharged well from the hospital. One patient developed parkinsonism after a follow-up of 2 years. There were no deaths. Conclusion: COP is relatively uncommon in Singapore. It has a low rate of short- and long-term complications.
Background: Patients having bariatric surgery are at moderate-to-high risk for post-operative ven... more Background: Patients having bariatric surgery are at moderate-to-high risk for post-operative venous thromboembolism (VTE), with pulmonary embolism representing the most common cause of post-operative death. The optimal dosing and duration of anticoagulant prophylaxis is uncertain. Aim: To evaluate the efficacy and safety of extended-duration, weight-adjusted tinzaparin for post-operative thromboprophylaxis after bariatric surgery. Methods: Retrospective cohort of 793 bariatric surgery patients who received routine post-operative weight-adjusted tinzaparin, 4,500-14,000 IU daily (75 IU/kg, rounded to the nearest pre-filled syringe) for 7 days after hospital discharge. The primary efficacy and safety outcomes were the frequency of VTE and major bleeding, respectively, within 30 days of surgery in patients receiving at least 1 dose of tinzaparin. Results: 793 patients who underwent bariatric surgery from 2009 to 2012 were reviewed. There were 44 (5.5%) patients excluded from analyses: need for therapeutic-dose anticoagulation (n=16); no post-operative tinzaparin (n=27); surgery aborted (n=1). There were 646 and 645 patients included in the 30-day efficacy and safety analyses, respectively (mean age, 44.6 years [SD 9.7], median body mass index, 47.1 kg/m2 [range: 19.4-81.0]). An additional 106 patients had outcome data only during hospital admission. VTE occurred in 1/645 patients (0.3%; pulmonary embolism) after hospital discharge and in 1/752 patients (0.1%; superior mesenteric vein thrombosis) in hospital. Major bleeding occurred in 12/645 patients (1.9%). Trough anti-Xa levels measured 7-10 days post-operatively were undetectable in 143/190 (75.3%) patients. In the other 47 patients the median trough anti-Xa level was 0.12 IU (range: 0.10-0.41). Conclusions: Weight-adjusted, extended-duration tinzaparin appears effective and safe for post-operative thromboprophylaxis after bariatric surgery. There was no drug accumulation with large doses of tinzaparin. Disclosures Siegal: Interactive Forums Inc.: Other: created educational slides; Daiichi Sankyo: Other: participated in an advisory board; Boerhinger Ingelheim: Other: participated in an advisory board; Portola Pharmaceuticals: Other: participated in an advisory board. Douketis:Bayer: Consultancy; Actelion: Consultancy; Biotie: Other: Advisory board; Sanofi-Aventis: Honoraria; The Medicines Company: Other: Advisory board; Janssen: Consultancy; Daiichi-Sankyo: Consultancy; Bristol-Myers Squibb: Consultancy, Honoraria; Pfizer: Honoraria; Boehringer Ingelheim: Consultancy, Honoraria.
Annals Academy of Medicine Singapore, Nov 15, 2013
Introduction: Novel oral anticoagulants (NOACs) have at least equivalent effi cacy compared to st... more Introduction: Novel oral anticoagulants (NOACs) have at least equivalent effi cacy compared to standard anticoagulants with similar bleeding risk. Optimal management strategies for bleeding complications associated with NOACs are currently unestablished. Materials and Methods: A working group comprising haematologists and vascular medicine specialists representing the major institutions in Singapore was convened to produce this consensus recommendation. A Medline and EMBASE search was conducted for articles related to the 3 available NOACs (dabigatran, rivaroxaban, apixaban), bleeding and its management. Additional information was obtained from the product monographs and bibliographic search of articles identifi ed. Results: The NOACs still has substantial interactions with a number of drugs for which concomitant administration should best be avoided. As they are renally excreted, albeit to different degrees, NOACs should not be prescribed to patients with creatinine clearance of <30 mLs/min. Meticulous consideration of risk versus benefi ts should be exercised before starting a patient on a NOAC. In patients presenting with bleeding, risk stratifi cation of the severity of bleeding as well as identifi cation of the source of bleeding should be performed. In life-threatening bleeds, recombinant activated factor VIIa and prothrombin complex may be considered although their effectiveness is currently unsupported by fi rm clinical evidence. The NOACs have varying effect on the prothrombin time and activated partial thromboplastin time which has to be interpreted with caution. Routine monitoring of drug level is not usually required. Conclusion: NOACs are an important advancement in antithrombotic management and careful patient selection and monitoring will permit optimisation of their potential and limit bleeding events.
Journal of Thrombosis and Haemostasis, Oct 1, 2018
Essentials • The optimal dose and duration of thromboprophylaxis after bariatric surgery are uncl... more Essentials • The optimal dose and duration of thromboprophylaxis after bariatric surgery are unclear. • We evaluated the safety of weight-adjusted tinzaparin prophylaxis in 1212 patients. • In-hospital rates of venous thromboembolism and major bleeding were 0.2% and 1.8% respectively. • In a subset of patients, trough anti-Xa levels did not show excessive anticoagulant activity. Summary. Background: Patients undergoing bariatric surgery are at moderate to high risk of venous thromboembolism (VTE). The optimal dose and duration of anticoagulant prophylaxis is uncertain. Objective: To evaluate the safety of extended-duration weight-adjusted tinzaparin after bariatric surgery. Patients/methods: We conducted a single-center retrospective cohort study of consecutive patients undergoing bariatric surgery who received weight-adjusted tinzaparin 4500-14 000 IU daily (75 IU kg À1 rounded to the nearest prefilled syringe) for 10 days after surgery (7-9 days post-hospital discharge). Primary safety outcomes were the frequency of VTE and major bleeding within 30 days of surgery in patients receiving at least one dose of tinzaparin. Results: A total of 1279 patients undergoing bariatric surgery between July 2009 and December 2012 were reviewed, of whom 1212 received weight-adjusted tinzaparin. Safety outcomes were collected for 819 patients at 30 days, and for 1212 patients in-hospital only. The median age was 45.0 years, median weight was 130.0 kg and 98.8% of patients underwent gastric bypass or sleeve gastrectomy. In patients completing 30 days of follow-up, VTE occurred in 4/819 (0.5%) and major bleeding occurred in 13/819 patients (1.6%). In-hospital rates of VTE and major bleeding during surgical admission were 3/1212 (0.2%) and 22/1212 (1.8%), respectively. Conclusions: Extended thromboprophylaxis with weight-adjusted tinzaparin appears to be a safe strategy after bariatric surgery, with low rates of postoperative VTE and major bleeding.
ObJeCTIve: To study the response of systolic and diastolic blood pressure (BP) and renal function... more ObJeCTIve: To study the response of systolic and diastolic blood pressure (BP) and renal function after renal artery stenting at three months, six months, one year and last follow-up. MeTHODS: Patients with significant renal artery stenosis who underwent angioplasty with stenting from January 1999 to September 2006 were analyzed. The BP and serum creatinine levels were recorded at baseline, three months, six months, one year and at last follow-up. Generalized estimating equations were applied to analyze the changes in blood pressure and serum creatinine over time. ReSulTS: There were 32 patients-21 Chinese, six Malay and five Indian. The male to female ratio was 1.3:1. The mean age (± SD) was 69.4±8.8 years. The mean follow-up time was 1.8±1.6 years (range 0.5 to six years). When compared with the baseline BP, there was significant improvement at three months, six months, one year and at last follow-up. In the diabetes mellitus (DM) group, there was deterioration in serum creatinine. In the non-DM group, there was stabilization of serum creatinine with improvement at one year. COnCluSIOn: Significant improvement in BP occurs in renal artery stenosis patients after stenting. In patients without DM, renal function remains stable or improves. However, in DM patients, especially those with proteinuria, there is deterioration in renal function.
Widening of the pre-vertebral space on a lateral neck radiograph is an indication of retropharyng... more Widening of the pre-vertebral space on a lateral neck radiograph is an indication of retropharyngeal abscess. Non infective isolated effusion in retropharyngeal space is rare. This article describes a case of nephrotic syndrome manifesting as retropharyngeal pseudoabscess.
Background: Stroke is a major cause of death and disability globally, especially in particular in... more Background: Stroke is a major cause of death and disability globally, especially in particular in the Asia-Pacific region, which is home to more than 4 billion people. Among the modifiable risk factors for stroke, hypertension is the strongest, but controllable to confer large outcome benefits. Objective: To investigate the association between hypertension and stroke burden in Asia-Pacific countries. Design and Methods: Stroke burden, as defined as age- and sex-standardised disability-adjusted life-years lost (DALYs) per 100,000 persons attributed to stroke, in Asia Pacific countries was extracted from the Global Burden of Disease (GBD) Study 2010. The age- and sex-standardised prevalence (%) of hypertension, defined as systolic blood pressure > 140 mmHg and diastolic blood pressure > 90 mmHg among adults aged 18 years or older, in these same countries was obtained from the World Health Organisation (WHO) database for 2015. Linear correlation was then estimated by calculating ...
Essentials • The optimal dose and duration of thromboprophylaxis after bariatric surgery are uncl... more Essentials • The optimal dose and duration of thromboprophylaxis after bariatric surgery are unclear. • We evaluated the safety of weight-adjusted tinzaparin prophylaxis in 1212 patients. • In-hospital rates of venous thromboembolism and major bleeding were 0.2% and 1.8% respectively. • In a subset of patients, trough anti-Xa levels did not show excessive anticoagulant activity. Summary. Background: Patients undergoing bariatric surgery are at moderate to high risk of venous thromboembolism (VTE). The optimal dose and duration of anticoagulant prophylaxis is uncertain. Objective: To evaluate the safety of extended-duration weight-adjusted tinzaparin after bariatric surgery. Patients/methods: We conducted a single-center retrospective cohort study of consecutive patients undergoing bariatric surgery who received weight-adjusted tinzaparin 4500-14 000 IU daily (75 IU kg À1 rounded to the nearest prefilled syringe) for 10 days after surgery (7-9 days post-hospital discharge). Primary safety outcomes were the frequency of VTE and major bleeding within 30 days of surgery in patients receiving at least one dose of tinzaparin. Results: A total of 1279 patients undergoing bariatric surgery between July 2009 and December 2012 were reviewed, of whom 1212 received weight-adjusted tinzaparin. Safety outcomes were collected for 819 patients at 30 days, and for 1212 patients in-hospital only. The median age was 45.0 years, median weight was 130.0 kg and 98.8% of patients underwent gastric bypass or sleeve gastrectomy. In patients completing 30 days of follow-up, VTE occurred in 4/819 (0.5%) and major bleeding occurred in 13/819 patients (1.6%). In-hospital rates of VTE and major bleeding during surgical admission were 3/1212 (0.2%) and 22/1212 (1.8%), respectively. Conclusions: Extended thromboprophylaxis with weight-adjusted tinzaparin appears to be a safe strategy after bariatric surgery, with low rates of postoperative VTE and major bleeding.
INTRODUCTION: Renal angioplasty has been increasingly used to treat significant renal artery sten... more INTRODUCTION: Renal angioplasty has been increasingly used to treat significant renal artery stenosis (RAS). At the Tan Tock Seng Hospital (Singapore), renal angioplasty patients are routinely admitted to the high dependency unit (HDU) postprocedure for monitoring. METHODS: The complications of the RAS patients were reviewed postangioplasty, and it was determined whether the patients could be monitored in the general ward (GW) instead of the HDU. Cases of patients with RAS of more than 50% who underwent angioplasty between January 1999 and September 2006 were reviewed retrospectively. RESULTS: There were 35 patients with significant RAS who underwent angioplasty. Thirty were monitored in the HDU. Five were monitored in the GW because there were no HDU beds available. Patients in the GW were monitored every 30 min for 6 h, then every hour for 24 h. No immediate complications or deaths were recorded in the present series. CONCLUSION: It may be safe and cost-effective to monitor patients with significant RAS postangioplasty in the GW.
Widening of the pre-vertebral space on a lateral neck radiograph is an indication of retropharyng... more Widening of the pre-vertebral space on a lateral neck radiograph is an indication of retropharyngeal abscess. Non infective isolated effusion in retropharyngeal space is rare. This article describes a case of nephrotic syndrome manifesting as retropharyngeal pseudoabscess.
Objective: We evaluate the efficacy of anticoagulant administration for isolated distal deep vein... more Objective: We evaluate the efficacy of anticoagulant administration for isolated distal deep vein thrombus (IDDVT), detected before orthopedic surgery. Materials and Methods: The study included 32 patients diagnosed with IDDVT before orthopedic surgery in our hospital between October 2011 and October 2017. They were divided into two groups: the pre-and post-operative therapy group, who were administered anticoagulants both pre-and post-operatively, and the post-operative therapy group, who were administered anticoagulants only after surgery due to risk of bleeding judged by an orthopedic surgeon. We compared the primary efficacy (change in IDDVT size) between the two groups. Results: The proportion of patients with increased postoperative IDDVT sizes was significantly larger in the post-operatively treated group than in the pre-and post-operatively treated group (44.4% vs. 8.7%, p=0.026). No case demonstrated an IDDVT extension proximal to the popliteal vein or presented with symptomatic pulmonary thromboembolism in this study. Conclusion: Based on our findings, we recommend that, in patients with IDDVT detected prior to orthopedic surgery and administered anticoagulant therapy only after the procedure because of a bleeding risk, a lower limb ultrasonography to re-evaluate the existing deep vein thrombus should be conducted before beginning rehabilitation.
We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The ... more We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The patient was a 32-year-old man who presented with a short history of throat discomfort and a choking sensation. Laryngoscopy identified bulging of the posterior pharyngeal wall that partially occluded the laryngeal inlet. A lateral neck x-ray revealed that the prevertebral space was widened, and computed tomography detected fluid in the retropharyngeal and parapharyngeal spaces. Neck exploration revealed that the edema had been caused by nonsuppurative fluid. Biochemical analyses revealed marked hypoalbuminemia and heavy proteinuria suggestive of nephrotic syndrome. Following surgery, the patient's symptoms resolved. Aseptic effusion into the retropharyngeal space is rare; reported etiologies include internal jugular vein thrombosis, neoplasia, radiation therapy, trauma, acute calcific tendinitis, hereditary angioedema, and myxedema of hypothyroidism. To the best of our knowledge, thi...
To study the response of systolic and diastolic blood pressure (BP) and renal function after rena... more To study the response of systolic and diastolic blood pressure (BP) and renal function after renal artery stenting at three months, six months, one year and last follow-up. Patients with significant renal artery stenosis who underwent angioplasty with stenting from January 1999 to September 2006 were analyzed. The BP and serum creatinine levels were recorded at baseline, three months, six months, one year and at last follow-up. Generalized estimating equations were applied to analyze the changes in blood pressure and serum creatinine over time. There were 32 patients - 21 Chinese, six Malay and five Indian. The male to female ratio was 1.3:1. The mean age (± SD) was 69.4±8.8 years. The mean follow-up time was 1.8±1.6 years (range 0.5 to six years). When compared with the baseline BP, there was significant improvement at three months, six months, one year and at last follow-up. In the diabetes mellitus (DM) group, there was deterioration in serum creatinine. In the non-DM group, ther...
With advances in modern imaging techniques, portal vein thrombosis (PVT) is being increasingly di... more With advances in modern imaging techniques, portal vein thrombosis (PVT) is being increasingly diagnosed. It has a wide ranging clinical spectrum from being an asymptomatic state to a potentially life-threatening situation. It is not unusual to find it as an incidental finding in the abdominal imagings done for other reasons. It is commonly associated with cirrhosis and abdominal malignancies and also has a strong association with prothrombotic disorders. It is often difficult for the clinicians to decide whether PVT is acute or chronic. This poses great challenges to its management strategies that include anticoagulants, thrombolysis, and surgical options. Timely diagnosis and appropriate management have great bearings on its outcomes of morbidity and mortality. In this clinician-oriented review, we have provided a concise review of clinical aspects of PVT and discussed various management strategies while addressing the common questions that come to a physician’s mind dealing with ...
INTRODUCTION Novel oral anticoagulants (NOACs) have at least equivalent efficacy compared to stan... more INTRODUCTION Novel oral anticoagulants (NOACs) have at least equivalent efficacy compared to standard anticoagulants with similar bleeding risk. Optimal management strategies for bleeding complications associated with NOACs are currently unestablished. MATERIALS AND METHODS A working group comprising haematologists and vascular medicine specialists representing the major institutions in Singapore was convened to produce this consensus recommendation. A Medline and EMBASE search was conducted for articles related to the 3 available NOACs (dabigatran, rivaroxaban, apixaban), bleeding and its management. Additional information was obtained from the product monographs and bibliographic search of articles identified. RESULTS The NOACs still has substantial interactions with a number of drugs for which concomitant administration should best be avoided. As they are renally excreted, albeit to different degrees, NOACs should not be prescribed to patients with creatinine clearance of <30 ...
We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The ... more We describe a case of nephrotic syndrome that manifested as a retropharyngeal pseudoabscess. The patient was a 32-year-old man who presented with a short history of throat discomfort and a choking sensation. Laryngoscopy identified bulging of the posterior pharyngeal wall that partially occluded the laryngeal inlet. A lateral neck x-ray revealed that the prevertebral space was widened, and computed tomography detected fluid in the retropharyngeal and parapharyngeal spaces. Neck exploration revealed that the edema had been caused by nonsuppurative fluid. Biochemical analyses revealed marked hypoalbuminemia and heavy proteinuria suggestive of nephrotic syndrome. Following surgery, the patient's symptoms resolved. Aseptic effusion into the retropharyngeal space is rare; reported etiologies include internal jugular vein thrombosis, neoplasia, radiation therapy, trauma, acute calcific tendinitis, hereditary angioedema, and myxedema of hypothyroidism. To the best of our knowledge, thi...
Introduction Human immunodeficiency virus (HIV) patients are at risk of developing thrombosis tha... more Introduction Human immunodeficiency virus (HIV) patients are at risk of developing thrombosis than general population. There are several intersecting mechanisms associated with HIV infection and antiviral therapy that are emerging, which may lead to vasculopathy and hypercoagulability in these patients. Methods We analyzed the HIV patients who followed up with our Vascular Medicine outpatient clinic with venous thromboembolism (VTE) over the past 3 years and followed them prospectively. The patients included were those who had minimum, regular follow-up of 3 months, with a Doppler scan in the beginning and last follow-up. Patients were analyzed for age, gender, race, site of thrombosis, coagulation factors, lipid panel, type of antiretroviral treatment, past or present history of infections or malignancy, CD4 absolute and helper cell counts at the beginning of thrombosis, response to treatment and outcome. Patients with HIV with arterial thrombosis were excluded. Results A total of ...
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Papers by Pankaj Handa