Postoperative deep vein thrombosis in the Taiwanese Chinese population

Deep vein thrombosis after major orthopedic surgery in Taiwan: A prospective cross-sectional study and literature review

BACKGROUND/PURPOSE

Postoperative venous thromboembolism is an important complication in Taiwan. We prospectively investigated the occurrence of deep vein thrombosis (DVT) after major orthopedic surgery without pharmacologic thromboprophylaxis in a cohort of 120 patients (46 males, 74 females, median age 71 years) at our institute.

METHODS

Color duplex compression ultrasonography (CUS) was used to detect DVT before and after the operation, while contrast venography was performed postoperatively for comparison and validation.

RESULTS

Total knee arthroplasty (TKA, 57 cases) and total hip arthroplasty (23 cases) were the most commonly performed operations. The rate of postoperative DVT was 7.5% (9/120), including five with proximal DVT and four with distal DVT. All were detected in the limbs on the operated side. Four of them were symptomatic DVT cases. Venography was performed in 19 patients and confirmed most findings of CUS, indicating the effectiveness of CUS for detecting DVT. The type of surgery (TKA) was significantly correlated with postoperative DVT. No clinically symptomatic pulmonary embolism or sudden death events were noted.

CONCLUSION

Nine out of 120 (7.5%) orthopedic patients without pharmacologic thromboprophylaxis developed postoperative sonographic DVT in our study. The DVT rate is consistent with other reports from various Asian countries and evidence from meta-analyses.

The rate and mortality of postoperative venous thromboembolism of moderate risk surgery in Asian patients without thrombo-prophylaxis: systematic review with meta-analysis

BACKGROUND

The general gynecologic and neurologic surgeries are regard as carrying moderate risk for postoperative venous thromboembolism (VTE). This review analyzed the postoperative VTE rate of these surgeries in Asia.

METHODS

Inclusion criteria were: prospective study; deep vein thrombosis (DVT) diagnosed by venography, ultrasonography, or radionucleotide scan; and no thromboprophylaxis. The pooled proportion was back calculated from Freeman-Tukey variant transformation, using a random effect model.

RESULTS

Medline, EMBASE, Cochrane Library, and KoreaMed were searched. Fourteen studies (total population of 1,625) published from 1974 to 2008 were included. In general surgery, the pooled rate of all-sites proximal, isolated distal DVT was 13.4, 2.1, and 11.8 % (radionucleotide scan). The cancer patients carried a higher all-sites DVT rate (19.7 % radionucleotide scan and 17.4 % ultrasound). Gynecologic and neurologic surgery had 3.1 % (ultrasound) and 3.8 % (radionucleotide scan) all-sites DVT rate. For general, gynecologic, and neurologic patients, the pooled rates of symptomatic DVT were 1.5, 0.2, and 1.0 % respectively. The pooled rate of symptomatic pulmonary embolism (PE) was 0.4 % for general surgery. No patients died from PE (pooled rate 0.2 %); however, a single PE death was reported in the excluded study.

CONCLUSIONS

Postoperative symptomatic VTE was relatively low in Asia. Further study is required to stratify VTE risk and the need for thromboprophylaxis in individual patients.

Venous thromboembolism after facelift surgery under local anesthesia: results of a multicenter survey

BACKGROUND

Venous thromboembolism (VTE) is a serious complication of cosmetic surgery, and studies have suggested that the incidence is not insignificant in facelift surgery. Use of local anesthesia over general anesthesia and shorter operative times are probable contributing factors to lower VTE incidence. Because there have been no large-scale assessments of VTE in facelifts as such, we investigated VTE incidence and relevant factors in facelift surgeries performed under local anesthesia only.

METHODS

We conducted a retrospective multicenter survey of facelift surgeons who utilize the American Society of Anesthesiologists level 1 oral anxiolysis and local diluted lidocaine anesthesia technique. Anonymous online surveys were sent to surgeons with questions regarding facelifts performed and VTE incidence over the previous 19 months.

RESULTS

Seventy-seven surgeons (93 % response rate) completed the survey, with 74 eligible surgeons reporting at least one facelift. Respondents reported five VTE events, for an overall VTE incidence of 1 event in 5,844 surgeries. Surgeons who reported performing facelifts at high volumes (>500 facelifts in 19 months) had a significantly lower VTE incidence than lower-volume surgeons (p = 0.011). High-volume surgeons also reported a significantly lower average operative time (p = 0.016), but for surgeries that did or did not result in VTE, there was no significant difference between surgeon-reported average operative times.

CONCLUSION

The low VTE incidence in this facelift series supports prior understanding that there is a low risk of VTE in surgery performed under local anesthesia and in surgery with shorter operative times. Limiting ancillary procedures to the face likely reduces operative time and likely also contributes to a lower VTE rate. The data further suggest that physicians performing facelifts more frequently tend to have shorter average operative times and overall lower VTE incidence.

LEVEL OF EVIDENCE IV

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A Prospective Study of Venous Thromboembolic Prophylaxis using Foot Pumps following Total Knee Replacement in a Chinese Population

Purpose

The purpose of this study was to evaluate foot pumps as mechanical prophylaxis for deep vein thrombosis (DVT) following total knee replacement (TKR) in a Chinese population.

Methods

All consecutive patients following TKR during 2002–2006 received routine duplex ultrasound surveillance for DVT 9 days postoperatively. The demographic data and risk factors were recorded. No medication was given for DVT prophylaxis in all patients.

Results

We evaluated 91 consecutive TKRs in 85 patients. Although 44 knee replacements (Group 1) done before December 2004 were not given foot pumps, 47 knee replacements (Group 2) done afterwards were given foot pumps. All patients were followed up for more than 6 months. DVT was detected in three cases (6.8%) in Group 1 compared with four knees (8.5%) in Group 2. Proximal thrombosis was observed in two knees (4.5%) in Group 1 compared with two knees (4.3%) in Group 2. No patient had pulmonary embolism. Six out of 59 (10.2%) patients who underwent the operations under general anaesthesia suffered from DVT, whereas one in 28 (3.6%) patients operated under spinal anaesthesia had DVT. All had no statistical significance.

Conclusion

The rate of proximal DVT after TKR was low (4.5%) without pharmacological prophylaxis. We advise against the use of pharmacological prophylaxis in Chinese population for TKRs because of the low risk of proximal DVT and its possible bleeding complications. Foot pump did not lower the rate of DVTfurther, and its use for DVT prophylaxis in TKR is not necessary.

Influence of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, B vitamins and other factors on plasma homocysteine and risk of thromboembolic disease in Chinese

BACKGROUND

Thromboembolic disease is a major cause of morbidity and mortality in many countries. Our previous study found that Chinese subjects carried the same polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene as described in Western studies. The aim of the present study was to determine the influence of MTHFR polymorphism, B vitamins and other factors on plasma homocysteine (Hcy) levels and risk of thromboembolic disease in Chinese.

METHODS

One hundred and six subjects were enrolled into the study. They were categorized into 4 groups: healthy individuals (n = 42); those with diabetes mellitus (n = 20); those with deep vein thrombosis (DVT) (n = 11); and those with coronary artery disease (CAD) (n = 33). Plasma levels of folic acid, vitamins B6 and B12, Hcy, and fasting blood sugar were measured; total cholesterol, triglycerides, complete blood count, and 677 C-->T mutation in MTHFR were determined.

RESULTS

Plasma Hcy was lowest in the healthy subjects, higher in diabetics, followed by patients with DVT, and highest in patients with CAD (p < 0.001, ANOVA). MTHFR C677T polymorphism was the common factor affecting plasma logHcy levels in all 4 groups of subjects. Triglycerides affected plasma logHcy in the CAD patients. For the 4 groups as a whole, MTHFR polymorphism, triglycerides, and vitamin B12 were the most significant factors influencing plasma Hcy.

CONCLUSION

We suggest that high plasma Hcy is an important risk factor for CAD. Other factors including MTHFR polymorphism, vitamin B12, triglycerides, total cholesterol, and gender might affect Hcy levels in different diseases and conditions.

The influence of age and smoking on hemostatic parameters in the chinese people

Plasma plasminogen activator inhibitor-1 (PAI) antigen, fibrinogen, factor VII, cholesterol, triglyceride (TG) and glucose were determined in 101 healthy subjects, who were divided into 10 subgroups according to age and smoking status. Factor VII and cholesterol were significantly higher in 50 healthy smokers than in the remaining 51 healthy non-smokers (p = 0.037 and 0.008, respectively). By dividing smokers and non-smokers each into 5 different age groups, we found that smoking could significantly increase PAI and/or factor VII, but not fibrinogen, in several age groups. On the other hand, age would significantly increase fibrinogen in either smokers or non-smokers, and this increase would be promoted by smoking. In conclusion, smoking could produce higher factor VII or PAI, whereas age could effect the significant increase of fibrinogen which was further promoted by smoking. Though aging cannot be avoided, smoking should be abstained especially in the old people to prevent the occurrence of thromboembolic diseases.

The incidence of proximal deep vein thrombosis following total knee arthroplasty in an Asian population: a Doppler ultrasound study

PURPOSE

To investigate the incidence of deep vein thrombosis (DVT) following total knee arthroplasty in an Asian population.

METHODS

A prospective study of 149 consecutive cases of total knee arthroplasty done for osteoarthritis was conducted over a 5-year period. All patients underwent duplex ultrasonographic assessment of the lower limbs within the first postoperative week.

RESULTS

The incidence of proximal DVT was found to be 4.38% in this study. Symptomology was statistically significant in predicting the presence of proximal DVT in all cases. General anaesthesia was associated with a statistically significant-higher incidence of DVT as compared with regional anaesthesia. There was a significant association between a sedentary lifestyle and the development of DVT.

CONCLUSION

The incidence of proximal DVT in Asian patients after total knee arthroplasty is higher than that previously reported for this demographic group.

Deep venous thrombosis after total hip or knee arthroplasty in a "low-risk" Chinese population

Scarcely any information has been published on deep vein thrombosis (DVT) in Chinese patients after total hip arthroplasty (THA) or total knee arthroplasty (TKA). However, generally, no prophylaxis is given to patients who do not have conventional high-risk factors because they are believed to be at "low risk." We performed a prospective study on 80 such "low risk" patients undergoing THA or TKA (58 TKA and 22 THA) without prophylaxis and performed duplex ultrasonography on both lower limbs 6 to 8 days after surgery. A total of 22 patients (27.5%) showed ultrasonographic evidence of DVT. Eighteen (31%) TKAs and 4 (18.1%) THAs were complicated by DVT. Three patients showed bilateral involvement, all of whom underwent TKA. Two patients had symptomatic pulmonary embolism. The sensitivity and positive predictive value of the clinical examination was 27.2% and 31.6%, respectively. This study showed that patients who are labeled "low risk" for DVT actually had a significant risk and suggests that the current practice of providing prophylaxis to only patients deemed at "high risk" should be revised.

Variations of prothrombin time and international normalized ratio in patients treated with warfarin

Prothrombin time is a standard screening test to monitor patients treated with oral anticoagulants. We hypothesize that INR measurements will not vary a lot within a given day in a given patient. The present study was thus conducted to compare the change of the international normalized ratio (INR) of prothrombin time (PT) within 1 day in patients treated with warfarin. Thirty such patients and nineteen healthy controls were enrolled into this study. PT was performed in four time points of a day in all subjects, two in the morning and two in the afternoon. The four INR values obtained were compared with each other to find little change in the series of time either in patients or in healthy controls. Neither were they affected by renal function, liver function, sex, age, hemoglobin, white cell count, platelet, treatment duration of warfarin, or alcoholic drinking. INR could be measured in any time of a day to have values equally valuable in clinical use.

Long-term treatment with warfarin in Chinese population

OBJECTIVE

To estimate the incidence of and risks for bleeding and thromboembolic events after warfarin anticoagulation. We also explored the dosage and international normalized ratio (INR) among Chinese patients during long-term warfarin therapy.

METHODS

The population in this retrospective study consisted of inpatients of the only medical center for northern Taipei City, whose initial course of warfarin therapy continued for more than four weeks. Enrollment began in June 1995 and ended in February 1996. Follow-up was completed in March 1998. Relevant data were collected by chart review. The rate of events was calculated using the Kaplan-Meier method, and risk factors were identified by the Cox proportional hazard model.

RESULTS

During the study period, 226 patients were identified. The total follow-up time was 248.7 patient-years. Sixty-one patients (27.0%) received anticoagulation for mechanical prosthetic valve, but their duration of therapy accounted for 48.6% of the total patient-years of follow-up. The starting dosage (mean +/- SD) was 3.4+/-1.4 mg/d (range 1.3-10); the maintenance dosage was 3.1+/-1.2 mg/d (range 1.2-7.7). There were 1060 dosing adjustments and 3398 INR measurements collected for these patients. The independent determinants of maintenance dosage were age, body weight, and indication of mechanical prosthetic valve. The INR was 1.9+/-0.5 (range 1.0-3.7). The cumulative probabilities for hemorrhage at 12, 24, and 34 months were 24.5%, 32.3%, and 38.4%, respectively. The corresponding figures for thromboembolism were 8.5%, 10.7%, and 10.7%, respectively. Three hemorrhages were fatal. After adjusting for other patient characteristics, increasing age was the only independent risk factor identified for bleeding.

CONCLUSIONS

Antithrombotic efficacy seemed to be maintained, although the mean INR was 1.9. Even so, the substantial incidence of bleeding, especially fatal bleeding, remains a concern. Low-intensity anticoagulation might be needed for Chinese patients during long-term warfarin therapy.

Causes of venous thrombosis in fifty Chinese patients

In a whole year from July 1997 to June 1998, a total of 50 patients with sonogram-proved venous thrombosis who called on our hematology clinic consecutively entered into the study. Their mean age was 59.1 +/- 17.5 years, range 18-83 years, and 29 were male. A series of examinations were performed in order to find out the cause of venous thrombosis. These examinations included antithrombin, protein C, protein S, plasminogen, heparin cofactor II, activated protein C ratio, factor V Leiden mutation, fibrinogen, factors VIII and XII, euglobulin lysis time, 677 C-->T mutation of methylenetetrahydrofolate reductase (MTHFR), prothrombin 20210 (PT 20210) A allele mutation, lupus anticoagulant, anticardiolipin antibody, and complete blood count. Five patients (10%) were found to have malignancy; an inferior vena cava thrombosis in one patient was due to venous compression by hydronephrosis; two patients had lupus anticoagulant; two had varicose veins of legs; two had protein C deficiency; four had protein S deficiency; two had plasminogen deficiency; two had antithrombin deficiency. No activated protein C resistance, elevated factor VIII level, factor V Leiden, PT 20210 A allele or heparin cofactor II deficiency was found in the present study. Homozygous MTHFR 677 C-->T gene mutation was found in 7 patients (14%); one of them also had a plasminogen deficiency. No possible risk factor of venous thrombosis could be found in 24 patients (48%). In conclusion, malignancy and protein S deficiency were the most frequent acquired and congenital causes of venous thrombosis in the Chinese, respectively.

Prevalence of activated protein C resistance in the Chinese population

In 1996, a total of 1700 subjects, including 461 healthy subjects and 1239 clinic patients, were randomized and consecutively entered into our study. Their mean age was 49.30+/-18.71 years, range 1-99 years. Of them, 1117 were male, and 583 were female. The mean age of the male was 42.96+/-17.64 years, and of the female, 52.60+/-18.41 years. The mean activated protein C ratio in 1700 subjects was 2.96+/-0.69, range 2.00-7.93. None of them had activated protein C ratio <2.0. The mean activated protein C ratio in the male was 2.81+/-0.63, and in the female was 3.04+/-0.71. None of the subjects was found to have activated protein C resistance. DNA analysis for the Arg 506-Gln mutation was also performed on 492 out of the 1700 subjects; none of them had this mutation. We suggested that the Chinese is not a race with the trait of activated protein C resistance.

Chronic venous insufficiency in a Chinese population: an anatomic and functional study by continuous-wave Doppler and photoplethysmography

A total of 1583 limbs in 878 patients who presented with symptoms of chronic venous insufficiency of the lower limbs were examined in the vascular laboratory. The anatomic distribution of valvular insufficiency was determined by continuous-wave Doppler ultrasound and functional severity was determined by the venous refilling time (VRT) using photoplethysmography. Severity of reflux was assessed using a four-class grading scale (classes 0 to 3) based on clinical and VRT criteria. A mixed incompetence of the valves in the superficial system and the perforators was encountered in the majority of patients (44% in class 0 and 85% in class 3). Deep vein incompetence was less common and usually consisted of isolated proximal incompetence of the common femoral vein (up to 32% in class 3) or was of a mixed type (21% in class 3). Isolated distal deep vein incompetence was uncommon. Proximal femoral vein incompetence and superficial system incompetence at the saphenofemoral junction were associated with severe reflux. There was significant improvement in the VRT in patients with more severe reflux (class 2 or 3) after application of an ankle tourniquet. Symptoms of moderate to severe chronic venous insufficiency and ankle ulceration may be a result of long-standing superficial system incompetence rather than deep venous disease and may thus be amendable to simple saphenofemoral ligation and interruption of perforators.

The influence of high fat diet on the fibrinolytic activity

High fat diet containing 50% fat was given to 28 Chinese healthy volunteers for 3 days. Their mean age was 28.04 years with SD 5.53. Blood glucose, cholesterol, triglyceride (TG) and venous occlusion test (VOT) were determined before and after diet. Tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI) were determined before and after VOT. After high-fat diet, blood glucose and cholesterol increased significantly (p = 0.031, 0.049 respectively), but other parameters did not. TPA increased significantly after VOT either before or after high-fat diet, but such increment was significantly less after high-fat diet (P < 0.05). In conclusion, the immediate effect of short-term high-fat diet included increased plasma levels of glucose and cholesterol, and impaired fibrinolytic response in stress condition.

Relationship of plasminogen activator inhibitor-1 with plasma insulin, glucose, triglyceride and cholesterol in Chinese patients with diabetes

Plasminogen activator inhibitor-1 (PAI) activity, plasma insulin, glucose, cholesterol and triglyceride (TG) concentrations were determined in 32 Chinese diabetic patients (mean age 61.4 yr) and 41 healthy controls (mean age 64.5 yr) to establish the relationships between these parameters. Insulin, glucose, cholesterol and triglyceride levels were significantly higher in the diabetics, whereas no significant difference of PAI activity was noted between groups. PAI activity was not affected by the increase of plasma insulin, cholesterol, TG or glucose. We have shown that PAI activity in Chinese diabetics was not affected by the common pathologic changes found in diabetes. This might be one of the reasons why fibrinolytic activity is not impaired in Chinese diabetics.