Deep venous thrombosis after strokes in Chinese

PREVALENCE, DISTRIBUTION AND DETERMINANTS OF DEEP VEIN THROMBOSIS IN ADULT INDOOR STROKE POPULATION OF PESHAWAR DIVISION, PAKISTAN

Background: Stroke is a devastating public health problem worldwide, considered as the third leading cause of death in developed countries, and the leading cause of disability among adults. Deep vein thrombosis (DVT), including pulmonary embolism (PE) as a sequel, is a serious complication of various medical conditions including stroke. The purpose of this study was to determine frequency of deep vein thrombosis among patients presented with stroke. Materials and methods: This study was descriptive (cross-sectional) study, conducted in the Department of Neurology, Lady Reading Hospital, Peshawar over 6 months. In the study a total of 196 patients were observed. Base line investigations were done and ultrasound was carried out to diagnose deep vein thrombosis. All the laboratory investigations and ultrasound were done by single experience pathologist and sonologist having minimum of five years of experience respectively. Observation and examination was done by neurologist who was not aware about the study and data was recorded in a predesigned proforma. To control confounders and bias in the study results, strict exclusion criteria had been followed. Results: In this study mean age was 63 years with standard deviation ± 28.34. Forty two percent patients were male and 58% patients were female. More over 8% patients had deep vein thrombosis. Conclusion:Our study concludes that the frequency of deep vein thrombosis was 8% among patients presented with stroke.

Venous thromboembolism in Japanese patients with fractures of the pelvis and/or lower extremities using physical prophylaxis alone

PURPOSE

To investigate the rate of venous thromboembolism (VTE) in Japanese patients with fractures of the pelvis and/or lower extremities using physical prophylaxis alone.

METHODS

Records of 66 men and 60 women aged 15 to 95 (mean, 57) years with fractures of the pelvis and/ or lower extremities were retrospectively reviewed. They were screened for VTE based on D-dimer values. Contrast-enhanced computed tomography and/or ultrasonography were performed when the D-dimer value did not decline predictably or exceeded 20 μg/ml even 5 days after injury or surgery. Physical prophylaxis for VTE in terms of graduated compression stockings and intermittent pneumatic compression were applied for all patients.

RESULTS

Of the 126 patients, 24 were detected to have VTE (10 of 29 with multiple fractures and 14 of 97 with single fractures). Six patients were detected to have asymptomatic pulmonary thromboembolism (PTE), whereas 20 patients were detected to have deep vein thrombosis (bilaterally in 7). The rates of VTE were high in patients with multiple fractures (35%), pelvic fractures (18%), and femoral shaft fractures (50%). The rate of PTE was high in patients with pelvic fractures (12%).

CONCLUSION

The rate of VTE in the Japanese patients was similar to that in western populations. Our screening method was useful for preventing fatal PTEs. Surgeons should be vigilant for VTE during the first 2 weeks after injury, especially in patients with multiple and pelvic fractures.

Incidence of venous thromboembolism in pelvic and acetabular fractures in the Japanese population

BACKGROUND

There are no detailed reports of the incidence of venous thromboembolism (VTE) in pelvic and acetabular fractures in the Asian population. The purpose of this study was to investigate the incidence of VTE in pelvic and acetabular fractures in the Japanese population.

METHODS

Forty-six Japanese patients with pelvic and acetabular fractures treated at our hospital from February 2004 to April 2011 were analyzed retrospectively. Until April 2009, VTE screening was performed by contrast-enhanced computed tomography (CT) or ultrasonography (US) when the D-dimer value did not decline predictably, still exceeded 20 µg/ml at 5 days after trauma and surgery, or increased >20 µg/ml after a period of decline. After April 2009, contrast-enhanced CT and US were performed routinely irrespective of the D-dimer value. Physical prophylaxis was performed in all patients. The effects of the presence of pelvic and acetabular fractures, fracture types, accompanying injuries, and screening strategies on the incidences of VTE and pulmonary thromboembolism (PTE) were investigated.

RESULTS

Overall, 19 patients (41.3%) were diagnosed with VTE and PTE in ten (21.7%). All were asymptomatic. Compared with trauma patients without pelvic and acetabular fractures treated during the same period, significantly higher incidences of VTE and PTE were observed in patients with pelvic and acetabular fractures. No significant differences were observed in the incidences of VTE and PTE between pelvic and acetabular fractures or between patients with and without accompanying injuries. Compared with the previous screening strategy, the detection rates of VTE and PTE were higher for the newer screening strategy; however, the difference did not reach statistical significance.

CONCLUSIONS

We should be vigilant for the high incidence of VTE, especially PTE, in patients with pelvic and acetabular fractures in the Japanese population.

Prevalence and risk factors of asymptomatic lower extremity deep venous thrombosis in Asian neurorehabilitation admissions in Singapore

OBJECTIVE

To determine the local prevalence and risk factors of asymptomatic lower limb deep venous thrombosis (DVT) among neurorehabilitation admissions.

DESIGN

A prospective observational single-center study.

SETTING

Tertiary rehabilitation center affiliated to a public hospital.

PARTICIPANTS

A total of 419 Asian neurorehabilitation admissions with a mean of 26 days to rehabilitation.

INTERVENTION

Admission screening protocol included quantitative D-dimer assay within 24 to 48 hours of rehabilitation admission and targeted hemiplegic/weaker lower-extremity venous duplex ultrasonography was performed if D-dimer assay level was elevated at 0.34 microg/mL or higher.

MAIN OUTCOME MEASURES

There were 251 (59.9%) men, and the subjects were predominantly Chinese (76.6%). Subjects had a mean age of 59+/-15 years. Admitting diagnoses included ischemic stroke (212), hemorrhagic stroke and subarachnoid hemorrhage (129), traumatic brain injury (59), and nontraumatic brain injury (19). The screening protocol included a quantitative D-dimer assay within 24 to 48 hours of rehabilitation admission, and hemiplegic/weaker lower-extremity venous duplex ultrasonography was performed if D-dimer assay level was elevated at 0.34 microg/mL or higher.

RESULTS

Altogether, 247 (58.9%) patients had an elevated D-dimer assay, and all underwent venous duplex ultrasonography. The incidence of lower-limb DVT was 5.01% (21), including 11 proximal and 10 distal DVT. No patients had clinical pulmonary embolism. Using 247 venous duplex ultrasonography results for analyses of correlates with logistic regression analyses, no significant demographic or clinical predictive factors for DVT were found.

CONCLUSIONS

This study confirms that asymptomatic lower limb DVT is indeed uncommon in Asian neurorehabilitation admissions. Possible reasons include genetic or ethnic protective factors, early walking initiated at rehabilitation, and timing of the admission protocol (median of 14 days postevent) when the maximal thrombotic risk was on the decline.

Safety and efficacy of lower-dose unfractionated heparin for prophylaxis of deep vein thrombosis and pulmonary embolism in an Asian population

The objective of this study is to analyze the tolerance and efficacy of the subcutaneous administration of a reduced 2,500-unit low-dose unfractionated heparin given for an efficacious, yet Asian population-sensitive, prophylaxis for deep vein thrombosis and fatal pulmonary embolism. Eighty-seven Japanese patients were operated on either for abdominal or pelvic complications or both, as well as for gynecologic conditions including ovarian, cervical, and corpus cancers. Thirty-two of the patients were administered the experimental low dose of unfractionated calcium heparin for prophylaxis. The 2,500 units of low-dose unfractionated heparin were given subcutaneously 2 h preoperatively and again 12 h postoperatively. Other standard methods of mechanical prophylaxis, including graduated compression stockings and intermittent pneumatic compression, were performed. Fifty-five of the patients were not administered heparin, but did receive the same standard mechanical graduated compression stockings and intermittent pneumatic compression prophylaxis. We compared the surgical and postsurgical complications noted for low-dose unfractionated heparin patients with the results of those who received no heparin prophylaxis and analyzed this data using the Mann-Whitney U-test. There was no significant difference in the mean of the blood loss volumes. There were also no significant differences found in the perioperative bleeding complications between the two groups. However, three (3/55; 6%) of the patients in the no-heparin group suffered a symptomatic pulmonary embolism, although none were fatal. There were no pulmonary embolism onsets in the heparin prophylaxis group. We feel that we have provided evidence that several serious complications, such as perisurgical hemorrhage, deep vein thrombosis, fatal pulmonary embolism, and increased postoperative recovery times, can be prevented by prophylaxis with 2,500-unit low-dose unfractionated heparin.

Early Deep Vein Thrombosis: Incidence in Asian Stroke Patients

Introduction: Deep venous thrombosis (DVT) is thought to be less common in Asians than in the Caucasian population. The incidence of asymptomatic DVT in high-risk groups in the Asian population has not been well studied. While DVT incidence among Caucasian stroke patients has been extensively studied and the need for prophylaxis established, the lack of data in Asian patients leaves physicians with no firm basis for adopting prophylactic protocols in the local population. Our aim was to prospectively establish the incidence of early DVT in immobilised stroke patients in a heterogenous Asian population. Materials and Methods: We screened 44 patients with significant hemiplegia from acute stroke. Doppler ultrasound, the currently accepted method of investigation for DVT, was used to study patients on admission and at 1 week post-stroke. While there was no standard prophylactic regime in use, none of the patients received heparin and only 2 were given compression stockings. Results: The incidence of DVT at 1 week was 2.4%. Review at 1 month detected another patient with DVT, bringing the overall incidence at 1 month to 4.8%. This is lower than in Caucasian populations, but is similar to another local study on a different group of high-risk patients. Conclusion: The low incidence of early DVT in hospitalised stroke patients of Asian ethnicity does not justify routine screening for this population. Further research to validate this should ideally include a comparison test for DVT as ultrasound may have inherently lower sensitivity in an asymptomatic population. Key words: Doppler ultrasound

Risk Factors and Presentation of Deep Venous Thrombosis among Asian Patients: A Hospital-Based Case-Control Study in Singapore

Deep venous thrombosis (DVT) is perceived to occur less frequently among Asians than Caucasians, although the reason for this has not been fully understood. Hence, there may be differences in risk factors and presentations among Asian patients compared to their Caucasian counterparts. This study examined the association of classical risk factors and presentations among Asian patients with DVT. We retrospectively reviewed 862 symptomatic patients referred to the vascular diagnostic laboratory in a hospital for suspected DVT over a 30-month period. Two hundred and seventy-seven patients (32.1%) tested positive for DVT on duplex ultrasound. After adjusting for age and gender, ethnicity was not a statistically significant demographic factor associated with DVT. Two hundred and seventy-one patients diagnosed as having DVT on ultrasound were matched for age, gender, and ethnicity to negative controls to study the significance of risk factors and presenting symptoms or signs. In multivariate analysis, independent risk factors for DVT included immobility (odds ratio [OR] = 2.61, 95% confidence interval [95% CI] 1.63-4.15], malignancy (OR = 1.77, 95% CI 1.01-3.10), and a history of thrombophilia (OR = 9.95, 95% CI 1.26-78.87). The significant forms of DVT presentation were limb swelling (OR = 2.53, 95% CI 1.41-4.54) and pulmonary embolism (OR = 11.45, 95% CI 3.23-40.59). Fever of more than 37.5 degrees C was a negative predictive factor (OR = 0.42, 95% CI 0.23-0.76). This study shows that the common risk factors of DVT such as surgery and fractures do not affect Asians as much as Caucasians. Instead, thrombophilia and underlying malignancy are prominent risk factors among Asians. Diagnosis of DVT in Asians based on clinical grounds can also be problematic as few presentations are specific.

Deep vein thrombosis following ischemic stroke among Asians

BACKGROUND

Deep vein thrombosis (DVT) is perceived as uncommon among Asian stroke patients. However, there is a paucity of published data, and thus, we studied the frequency, characteristics and prognosis of DVT following ischemic stroke in Asian patients with lower limb paresis.

METHODS

Doppler ultrasound scans of the lower limbs were performed at days 7-10 and 25-30 after stroke onset. The functional status of patients was assessed at 6 months using the modified Rankin scale.

RESULTS

DVT was detected in 30% of patients at days 7-10 and in 45% of patients at days 25-30. Most thromboses were distal. There were significant associations of age and degree of weakness with the presence of DVT at days 25-30, but not at days 7-10. DVT in the first month after stroke was associated with poorer outcome at 6 months.

CONCLUSIONS

DVT following ischemic stroke among Asians is common and associated with poor functional outcome.

Pulmonary thromboembolism in Asians/Pacific Islanders in the United States: analysis of data from the National Hospital Discharge Survey and the United States Bureau of the Census

PURPOSE

To assess the rate of diagnosis of deep venous thrombosis, pulmonary embolism, and venous thromboembolism; the incidence in hospitalized patients; and mortality from pulmonary embolism among Asians/Pacific Islanders in the United States.

METHODS

The number of patients discharged from hospitals with a diagnostic code for pulmonary embolism or deep venous thrombosis from 1990 through 1999 was obtained from the National Hospital Discharge Survey. Population estimates and deaths from pulmonary embolism from 1990 through 1998 were obtained from the United States Bureau of the Census.

RESULTS

Rate ratios of 10-year age-adjusted rates of diagnosis of deep venous thrombosis, pulmonary embolism, and venous thromboembolism comparing Asians/Pacific Islanders with whites and African Americans ranged from 0.16 to 0.21. Rate ratios comparing incidences in hospitalized patients ranged from 0.32 to 0.42. The age-adjusted rate ratio of mortality in "others" (which included Asians/Pacific Islanders) was 0.29 (95% confidence interval [CI]: 0.01 to 0.87) compared with whites and 0.14 (95% CI: 0.0 to 0.58) compared with African Americans.

CONCLUSION

Rates of deep venous thrombosis, pulmonary embolism, and venous thromboembolism; incidences in hospitalized patients; and the mortality rate from pulmonary embolism were markedly lower in Asians/Pacific Islanders than in whites and African Americans. Clinical assessment of the prior probability of venous thromboembolic disease at the bedside should probably be adjusted based on these ethnic differences.

Postoperative venous thromboembolism in Asia: a critical appraisal of its incidence

OBJECTIVES

Venous thromboembolism (VTE) has historically been perceived to be a rare disorder in Asia. However, new evidence has emerged recently that contradicts this perception. The question of routine VTE prophylaxis has been hotly debated in Asia due to disagreement on its incidence. We reviewed and analysed studies on postoperative VTE in Asian patients to determine if the condition was indeed rare and if the routine prophylactic measures as recommended by internationally accepted guidelines should be adopted in Asia.

METHODS

A review of published reports, from 1966 to December 2002, on deep vein thrombosis (DVT) and pulmonary embolism (PE) in the Asian population was made. A literature search of studies published in English was conducted via a detailed MEDLINE search. Studies had to attain a minimum inclusion and quality criteria to be accepted for the review, including the diagnostic modality used for the diagnosis of VTE. The appraisal was carried out independently and accepted by at least two of the three authors. The study population was classified into orthopaedic and general surgical/colorectal groups.

RESULTS

Twelve orthopaedic publications reviewed revealed an incidence of postoperative DVT of 10% to 63%. Six general and colorectal surgical publications reported an incidence of DVT ranging from 3% to 28%. The incidence was slightly lower than the reported incidence of 40% to 80% following orthopaedic surgery and 28% to 44% following general surgical operations in studies reporting on Caucasian populations.

CONCLUSION

While there is a wide variation in the incidence of DVT and VTE as reported in the Asian population, these diseases are by no means rare. The wide variation could be due to the study designs, heterogeneity of the procedures performed and the application of different diagnostic criteria. Results based on prospective studies with objective diagnostic criteria confirm the incidence of VTE as common. Routine chemoprophylaxis must be seriously considered in high-risk patients.

Venous thromboembolism in pregnant Chinese women

OBJECTIVE

To evaluate the incidence, disease pattern, and risk factors for thromboembolism in pregnant Chinese women.

METHODS

We conducted a study from January 1998 to December 2000. Women with thromboembolic diseases were identified and their case records retrieved and reviewed. Demographic characteristics were compared between women with and without thromboembolism.

RESULTS

Thirty-two women were diagnosed as having thromboembolic disease during the study period. The total number of deliveries over the study period was 16,993, giving an incidence of 1.88 per 1000 deliveries. There were two cases of pulmonary embolism and one resulted in a maternal death. The others had deep vein thrombosis of which over 80% were limited to calf veins only. The ultrasound examinations requested for suspected deep venous thrombosis before and after the event of maternal death were 1.62 and 10.7 per 1000 deliveries (P <.001); and the corresponding cases of deep venous thrombosis diagnosed were 0.29 and 2.94 per 1000 deliveries, respectively (P <.001). The majority (75%) of cases were diagnosed in the postpartum period, mainly after cesarean delivery. Women with venous thromboembolism were older, had higher body mass index, and a higher incidence of preeclampsia.

CONCLUSION

Thromboembolic disease is not uncommon among pregnant Chinese women. The incidence was similar to that of the white population, although the sites of vascular occlusion were different. The long-standing belief that thromboembolism is rare among Chinese is at least partly because of underdiagnosis.

Risk of pulmonary embolism and/or deep venous thrombosis in Asian-Americans

Several reports from Asian countries suggest a low prevalence of pulmonary embolism (PE) and deep venous thrombosis (DVT) in Asians, and sparse US data show that a slightly higher prevalence of PE/DVT in "nonwhites" than in whites is evident in all geographic regions except the Pacific region (California, Oregon, and Washington) where "nonwhites" include a larger proportion of Asians and Hispanics than in other US locations. We prospectively studied PE/DVT hospitalizations in 128,934 persons in relation to traits determined at health examinations in 1978 to 1985. Through 1994, 337 persons were subsequently hospitalized for PE and/or DVT (for PE first, n = 206). Cox proportional-hazards models with 9 covariates were used. In multivariate models, the following RRs (95% confidence intervals) were found for PE/DVT combined: black/white = 1.1 (0.4 to 1.4); Hispanic/white = 0.7 (0.3 to 1.5); and Asian/white = 0.2 (0.1 to 0. 5; p = 0.002). The lower risk of Asians was present in each sex and for persons first hospitalized for either PE or DVT. Covariates with significant positive relations to risk were age, male sex, body mass index, and a composite coronary disease risk/symptom variable; covariates not significantly related were education, marital status, smoking, and alcohol. These data suggest that Asians have very low risk of PE/DVT, which may account for US geographic variations in white/non-white risk differences. Possible explanations include the absence of hazardous mutations or unspecified PE/DVT protective traits in Asians.

Low dose oral anticoagulation therapy in Chinese children with congenital heart disease

OBJECTIVES

This study aims to evaluate the efficacy of a low dose warfarin regimen for Chinese children requiring anticoagulation therapy and its safety when monitored on an outpatient basis. Current recommendations are based on extrapolations from the adult experience and a high target international normalised ratio (INR) is adopted amongst the Western countries.

METHODOLOGY

This is a 10-year retrospective study from January 1986 to June 1996. Effectiveness of warfarin therapy was monitored by the prothrombin time, standardised and expressed as the INR. A target INR of 1.5-2.5 was adopted for children with cardiac diseases requiring anticoagulation therapy for primary and secondary prophylaxis against thromboembolism. From the clinical records, demographic data, induction warfarin dosage, changes of dosages and related events on follow-up, frequency of outpatient visits, complications and serial INR results were reviewed.

RESULTS

Thirty-five patients (23 boys, 12 girls) were included with a mean age at initiation of warfarin therapy of 8.4+/-5.8 years. Amongst these, 66% (n = 23) were after isolated valvar replacement, 28% (n = 10) after Fontan operation with or without valvar replacement and 6% (n = 2) after deep vein thrombosis. Regression estimate of the induction dose was 0.05-0.13 mg x kg(-1) in order to achieve the target INR range after 2 days of warfarin therapy. The daily maintenance warfarin dose was correlated with the bodyweight [dose (mg x day(-1))= 0.04 x bodyweight (kg) + 0.87, r = 0.63, P<0.0001]. Young children required significantly higher daily warfarin maintenance dose when adjusted for bodyweight [dose (mg x kg day(-1)) = antilog(10)¿-0.02 x age (years)- 0.80¿, r = -0.74, P<0.0001]. The mean maintenance warfarin dosage was significantly lower in patients after the Fontan operation, with or without valvar replacement, in the absence of apparent liver dysfunction. The total period of followup was 159 patient-years. No serious bleeding complications or embolic phenomena were documented. One patient died of thrombosis of the mitral valve prosthesis. The overall incidence of thrombosis was 0.6 per 100 patient-years.

CONCLUSIONS

A low dose warfarin regimen to maintain a target INR of 1.5-2.5 provides adequate protection in Chinese children against thromboembolism whilst allowing safe outpatient monitoring of the anticoagulation status.

Protein S and protein C levels in Chinese women during pregnancy, delivery and the puerperium

The plasma levels of protein S and protein C related antigens were determined in a group of normal pregnant Chinese women and a group of normal non-pregnant controls, using the sandwich technique of enzyme immunoassay with commercial kits. Compared with non-pregnant controls, plasma protein S levels were significantly lower during pregnancy, labour, parturition and the early puerperium. There was no significant difference in protein S levels between pregnancy, labour and puerperium. On the other hand, maternal plasma protein C levels during pregnancy and before delivery were similar to those in controls, but a significant increase was found during the third stage of labour. This increase did not persist into the early puerperium. The observed increase in protein C level immediately after delivery in our study may represent a physiological response to counter the tendency towards venous thrombosis in the parturient women, and may help to explain the almost negligible occurrence of thromboembolism in Chinese obstetric patients.

Venous thrombosis in haemoglobin H disease after splenectomy

While venous thrombosis and pulmonary embolism are rare among the Chinese, two of nine patients with haemoglobin H disease developed these complications after splenectomy. The clinical data of the two patients were reported and the relevant literature reviewed. It was concluded that the persistent thrombocytosis and an intravascular haemolysis, particularly prominent in this form of thalassaemia, are contributory to the hypercoagulable state.