Venous Thromboembolism: Review of Clinical Challenges, Biology, Assessment, Treatment, and Modeling.

Venous thromboembolism (VTE) is a massive clinical challenge, annually affecting millions of patients globally. VTE is a particularly consequential pathology, as incidence is correlated with extremely common risk factors, and a large cohort of patients experience recurrent VTE after initial intervention. Altered hemodynamics, hypercoagulability, and damaged vascular tissue cause deep-vein thrombosis and pulmonary embolism, the two permutations of VTE. Venous valves have been identified as likely locations for initial blood clot formation, but the exact pathway by which thrombosis occurs in this environment is not entirely clear. Several risk factors are known to increase the likelihood of VTE, particularly those that increase inflammation and coagulability, increase venous resistance, and damage the endothelial lining. While these risk factors are useful as predictive tools, VTE diagnosis prior to presentation of outward symptoms is difficult, chiefly due to challenges in successfully imaging deep-vein thrombi. Clinically, VTE can be managed by anticoagulants or mechanical intervention. Recently, direct oral anticoagulants and catheter-directed thrombolysis have emerged as leading tools in resolution of venous thrombosis. While a satisfactory VTE model has yet to be developed, recent strides have been made in advancing in silico models of venous hemodynamics, hemorheology, fluid-structure interaction, and clot growth. These models are often guided by imaging-informed boundary conditions or inspired by benchtop animal models. These gaps in knowledge are critical targets to address necessary improvements in prediction and diagnosis, clinical management, and VTE experimental and computational models.

Thromboembolic outcomes are decreased with the use of a standardized venous thromboembolism risk assessment and prophylaxis protocol for patients undergoing superficial venous procedures.

OBJECTIVE: Patients with venous insufficiency can be treated with ablation or phlebectomy, or both. Patients undergoing superficial venous procedures have an elevated risk of deep vein thrombosis (DVT) and pulmonary embolism (PE). At our institution, we initiated a standardized protocol in which patients with a Caprini score (2005 version) of ≥8 are treated with 1 week of prophylactic anticoagulation after the procedure. Duplex ultrasound was performed at 1 week and then within 90 days after the procedure. This aim of the present study was to determine the thrombotic and clinical outcomes after superficial vein procedures using a standardized protocol for DVT/PE risk assessment and prophylaxis. METHODS: We performed a retrospective analysis of prospectively collected data of superficial vein procedures from 2015 to 2021 at a single center. The patient demographics, CEAP (Clinical-Etiology-Anatomy-Pathophysiology) clinical class, venous clinical severity score, patient-reported outcomes, treatment type, Caprini scores, pre- and postoperative anticoagulation use, and outcomes were collected. Descriptive statistics were used for the patient demographics, procedure details, and unadjusted surgical outcomes. Multivariable logistic regression was used to evaluate the relationship between procedure type and DVT and PE after adjusting for patient characteristics, disease severity, periprocedural anticoagulation, and Caprini score. RESULTS: A total of 1738 limbs were treated with ablation (n = 820), phlebectomy (n = 181), or ablation and phlebectomy (n = 737). More patients were women (67.1%) and White (90.9%). The overall incidence of DVT/PE was 1.4%. Patients undergoing ablation with phlebectomy had higher rates of DVT/PE (2.7%) than those undergoing ablation (0.2%) or phlebectomy alone (1.7%; P < .01). However, only 30% of DVTs were above the knee. On multivariate analysis, only the procedure type predicted for DVT/PE. However, patients undergoing ablation and phlebectomy achieved better patient-reported outcomes (Caprini score, 5.9) compared with those undergoing ablation (Caprini score, 7.2) or phlebectomy (Caprini score, 7.9) alone (P < .01). The best improvement in the venous clinical severity score was seen with phlebectomy alone. CONCLUSIONS: The expected difference in the DVT/PE rates between high- and low-risk groups did not materialize in our patients, perhaps secondary to the additional chemoprophylaxis prescribed for the high-risk cohort (Caprini score, ≥8). These results call for a randomized trial to assess the efficacy of a standardized protocol in the reduction of DVT/PE after superficial vein procedures.

A multicentre observational study of the prevalence, management, and outcomes of subsegmental pulmonary embolism.

BACKGROUND: The incidence of subsegmental pulmonary embolism (SSPE) has increased with improvements in imaging technology. There is clinical equipoise for SSPE treatment, with conflicting evidence of improved mortality or reduced venous thromboembolism recurrence with anticoagulation. SSPE studies have significant heterogeneity and often lack adequately matched disease comparator groups. OBJECTIVES: To determine the prevalence, management, and outcomes of SSPE and compare them to patients with main, lobar, segmental, and no pulmonary embolism (PE). PATIENTS/METHODS: All adult patients undergoing CT pulmonary angiography (CTPA) between 2013 and 2019, at 3 UK hospitals were included in the study. CTPA reports were text mined for language relating to PE, and then further manually screened for the presence and anatomical location of PE. Patient groups were propensity matched by age, sex, and year of CTPA prior to analysis. 3-month outcomes of major bleeding, VTE recurrence, and death were recorded. RESULTS: 79 (3.8%) SSPEs were identified from 2,055 diagnoses of PE, and 14,300 CTPA reports. 44 (56%) of SSPEs were single artery emboli, 25 (32%) were multiple unilateral emboli, and 10 (13%) were multiple bilateral emboli. Mortality, VTE recurrence and major bleeding were similar at 3 months across all groups. 87.3% of SSPE imaging reports had an additional radiological diagnosis, with pleural effusion (30%), consolidation (19%), and cardiomegaly (19%) being the most common. CONCLUSION: The prevalence of SSPE was 3.8% of all PEs and there were a substantial number of additional radiological findings in the SSPE group that may have accounted for their symptoms.

A systematic review of routine post operative screening duplex ultrasound after thermal and non-thermal endovenous ablation.

OBJECTIVE: The Society of Vascular Surgery and the American Venous Forum recommend duplex ultrasound (DUS) following endovenous ablation. However, this screening may not be cost-effective or clinically indicated. The most common abnormal finding, endovenous heat-induced thrombosis (EHIT level 1-2), represents extension of thrombus from the saphenous <50% across the femoral or popliteal vein, which is thought to have a benign course regardless of intervention. The likelihood of venous thromboembolism (VTE) after thermal and non-thermal ablations was explored to determine the utility of routine postoperative DUS. METHODS: This is an updated and expanded systematic review including data from randomized trials and large observational studies (≥150 patients) of thermal and non-thermal ablations, examining the incidence of VTE. Using PubMed and EMBASE, 4584 publications were screened from 2000 through 2020. After applying inclusion and exclusion criteria, 72 studies were included. Random effects DerSimonian-Laird method was conducted to obtain the pooled incidence. We calculated the number of tests needed to detect one VTE, and the cost was derived from Center for Medicare Services tables. RESULTS: A total of 31,663 patients were included. The pooled incidence of EHIT II-IV, deep venous thrombosis (DVT), and pulmonary embolism (PE) was 1.32% (95% confidence interval [CI], 0.75%-2.02%); DVT (excluding EHIT), 0.20% (95% CI, 0.0%-0.2%); EHIT (I-IV), 2.51% (95% CI, 1.54%-3.68%); and EHIT (II-IV), 1.00% (95% CI, 0.51%-1.61%). There was no mortality. There was a lower DVT rate in thermal vs non-thermal ablations (0.23% vs 0.43%; P = .02); however, for all VTE (EHIT I-IV + DVT + PE), thermal techniques had more thrombosis (2.5% vs 0.5%; P <.001). When clinical significance is defined as DVT + EHIT (II-IV), 175 studies are needed to identify one VTE, costing $21,813 per "significant VTE." Patients receiving pharmacological prophylaxis had less EHIT I-IV compared with those who did not (3.04% vs 1.63%; P < .001); those who received DUS during the first post-op week had three times higher EHIT incidence compared with those whose first DUS was >7 days postoperative (6.6% vs 2.4%; P < .001). CONCLUSIONS: For thermal and non-thermal endovenous ablations, the incidence of VTE diagnosed with routine DUS is small and without clear clinical significance but caries a high cost. The Society of Vascular Surgery and the American Venous Forum recommendation to perform DUS within 72 hours is not justified by these data. We recommend a more targeted post-ablation scanning protocol including symptomatic patients and those at high risk.

Venous Duplex Ultrasound Surveillance in the Neurosurgical Population: A Single-Center Quality Improvement Initiative.

BACKGROUND: Venous thromboembolism (VTE) represents a significant source of morbidity and mortality in the inpatient population and is considered a leading preventable cause of death among inpatients. Neurosurgical inpatients are of particular interest because of the greater rates of immobility, steroid use, and potential consequences of postoperative hemorrhage. A consensus protocol for VTE screening in this population has not yet been developed, and institutional protocols vary widely. METHODS: We performed a retrospective review of lower extremity venous duplex ultrasonography (VDUS) usage at our institution and applied this information to the development of a neurosurgery department protocol, with consideration of high-risk patient risk factors and indications for VDUS ordering. We then implemented this protocol, which consisted of preoperative screening of patients at high risk of VTE and limited postoperative surveillance, for a 6-month period and compared VDUS usage and VTE occurrence. RESULTS: Preoperative VDUS screening before nonemergent neurosurgical procedures in high-risk patients with active cancer, an inability to ambulate, or a history of deep vein thrombosis (DVT) identified proximal DVTs that were then treated. Postoperative routine surveillance VDUS scans only diagnosed incidental isolated calf DVT for which no clinically relevant sequelae occurred. Overall, postoperative surveillance VDUS usage decreased significantly (66.9% vs. 13.5%; P = 0.001). CONCLUSIONS: Our findings lend support to preoperative screening of high-risk patients and suggest that routine postoperative VDUS surveillance of asymptomatic patients is unnecessary.

Assessment of the frequency of deep venous thromboembolism in obstructive sleep apnea syndrome.

The present study aimed to investigate the frequency of deep venous thrombosis (DVT) among patients with obstructive sleep apnea syndrome (OSAS). Patients who referred the preliminary diagnosis of OSAS were included in this study. D-dimer levels of all patients were measured, and D-dimer (+) patients were evaluated by Doppler USG of the lower-extremity. Mean age of the patient group was 52 ± 12 years and 31.8% (76/239) were women. The rate of D-dimer positivity among severe-OSAS cases (15/85) was significantly higher compared to the rest (13/154) (17.6% and 8.4%, respectively; p = 0.034). The risk of D-dimer positivity was elevated by 2.3 folds in severe-OSAS cases (OR: 2,324, 95% confidence interval: 1.048-5.152). Among 28 D-dimer (+) cases, 4 (14.2%) had DVT as demonstrated by USI of the lower-extremity. All four cases with DVT had severe OSAS. D-dimer was positive in 17.6% (15/85) of all severe OSAS cases. DVT was diagnosed in 4.7% (4/85) of severe-OSAS cases. DVT frequency was 26.6% (4/15) in D-dimer (+) severe-OSAS. Findings of this study indicate that severe-OSAS can be a significant risk factor for DVT. Additionally, data obtained in this study underline the benefits of questioning severe-OSAS patients with respect to DVT symptoms, investigating D-dimer levels and evaluating D-dimer (+) severe-OSAS cases for DVT prophylaxis.

Application of the Caprini Risk Assessment Model for Evaluating Postoperative Deep Vein Thrombosis in Patients Undergoing Plastic and Reconstructive Surgery.

BACKGROUND: The optimal approach for assessing the risk of venous thromboembolism (VTE) in patients undergoing plastic surgery is yet to be established. This study aimed to determine the validity of the Caprini Risk Assessment Scale in identifying patients undergoing plastic surgery who are at a high risk of developing VTE. METHODS: Between December 2014 and November 2015, we enrolled 90 patients. Risk factors for VTE were assessed at baseline. The Caprini Risk Assessment Model was used to stratify patients into Caprini <4, Caprini 5-6, Caprini 7-8, and Caprini >8 groups before examination. We preoperatively screened for deep vein thrombosis (DVT) using duplex ultrasound. During operation, surgical duration and blood loss were recorded. Duplex ultrasound was repeated 2 and 7 days postoperatively to evaluate for DVT. We used a univariate analysis to determine risk factors for postoperative VTE. Confounding predictors were finally tested using a multivariate logistic regression analysis. RESULTS: One patient had preoperative DVT and was excluded from the study. Eighty-nine patients were included in the final analyses. Of the 89 patients, 7 (8%) developed postoperative DVT. Mean age, body mass index, Caprini score, and surgical duration were significantly higher in patients who developed postoperative DVT. Variables associated with increased risk of postoperative DVT using univariate analysis were Caprini scores of 7-8 and >8. Multivariate logistic regression analysis finally identified Caprini scores 7-8 [odds ratio (OR) 13, 95% confidence interval (CI) 1.67-101.98, P = 0.014] and >8 (OR 19.5, 95% CI 1.02-371.96, P = 0.048) to be independently associated with postoperative DVT. CONCLUSIONS: Although the incidence of postoperative DVT is relatively low among patients undergoing plastic surgery, Caprini scores can be used to predict postoperative VTE complications.

Analysis of venous thromboembolism in neurosurgical patients undergoing standard versus routine ultrasonography.

Routine screening of high-risk asymptomatic trauma or surgical patients for venous thromboembolism (VTE) is controversial. Studies suggest against screening while others recognize that some patients at high risk may benefit. The purpose of this pilot study is to evaluate the benefit of routine screening using doppler ultrasonography for the early detection of deep venous thrombosis (DVT) in post-operative neurosurgical patients. This was a quasi-experimental study at a major academic tertiary care medical center. A total of 157 adults underwent cranial or spinal surgical interventions from March through August 2017 and received either standard screening (n = 104) versus routine ultrasonography screening (n = 53). There was no significant difference in incidence of DVT between the two groups: 11 (11%) in the standard screening group versus 5 (9%) in the routine screening group, p = 0.823. Upper and lower extremity ultrasonography was performed in 43 (41%) of the standard screening group versus 53 (100%) in the routine screening group, p < 0.001. DVT was identified in nearly one of every 6 ultrasonography screenings in the standard screening group versus 27 ultrasonography screenings required to identify one DVT in the routine screening group. There were the same number of screenings for upper extremity ultrasonography, but they did not yield or detect DVT; instead only superficial, untreatable, DVTs were reported. Total cost to diagnose one DVT, including screening and labor, averaged $13,664 in the standard group versus $56,525 in the routine group. Routine screening in neurosurgical patients who received VTE prophylaxis was not associated with lower incidence of VTE and mortality attributed to PE. Thus, routine screening may not be cost effective to prevent complications from DVT incidence.

Outcomes following a negative computed tomography pulmonary angiography according to pulmonary embolism prevalence: a meta-analysis of the management outcome studies.

Essentials Computed tomographic pulmonary angiography (CTPA) is used to exclude pulmonary embolism. This meta-analysis explores the occurrence of venous thromboembolic events (VTE) after a CTPA. Occurrence of VTE after a negative CTPA is ˜8% in study subgroups with a prevalence of PE ≥ 40%. CTPA may be insufficient to safely rule out VTE as a stand-alone diagnostic test for this subgroup. SUMMARY: Background Outcome studies have reported the safety of computed tomographic pulmonary angiography (CTPA) as a stand-alone imaging technique to rule out pulmonary embolism (PE). Whether this can be applied to all clinical probabilities remains controversial. Objectives We performed a meta-analysis to determine the proportion of patients with venous thromboembolic events (VTE) despite a negative CTPA according to pretest PE prevalence. Methods We searched MEDLINE, EMBASE and the Cochrane Library (January 1990 to May 2017) for outcome studies recruiting patients with suspected PE using CTPA as a diagnostic strategy. The primary outcome was the cumulative occurrence of VTE at 3 months following a negative CTPA. Results Twenty-two different studies were identified. VTE was confirmed in 2.4% of patients (95% CI, 1.3-3.8%) either at the time of the index event or in the 3 months follow-up. Subgroup analyses suggested that the cumulative occurrence of VTE was related to pretest prevalence of PE, as VTE occurred in 1.8% (95% CI, 0.5-3.7%), 1.4% (95% CI, 0.7-2.3%), 1.0% (95% CI, 0.5-1.8%) and 8.1% (95% CI, 3.5-14.5%) of subgroups of patients with a PE prevalence < 20%, 20-29%, 30-39% and ≥ 40%, respectively. This was further confirmed using meta-regression analysis. Conclusions The negative predictive value of CTPA for VTE varies according to pretest prevalence of PE, and is likely to be insufficient to safely rule out VTE as a stand-alone diagnostic test amongst patients at the highest pretest probability of VTE. Prospective studies are required to validate the appropriate diagnostic algorithm for this subgroup of patients.

Risk of Venous Thromboembolism after a Single Normal Proximal Lower Extremity Venous Ultrasound.

CONTEXT: The optimal lower extremity venous ultrasound (US) protocol to diagnose deep venous thrombosis of the popliteal and more proximal veins is unclear. OBJECTIVE: To determine the three-month rate of symptomatic venous thromboembolism (VTE) and clinical outcomes of inpatients and ambulatory patients with normal findings on single venous ultrasound of the popliteal and more proximal veins (single proximal US). DESIGN: Single proximal US results and clinical data of all inpatient and ambulatory patients with suspected acute deep venous thrombosis were retrospectively reviewed during a 12-month period between January and December 2014. Three-month follow-up data were reviewed for all these patients, who received all their care from a single geographically isolated health maintenance organization. MAIN OUTCOME MEASURES: Three-month rate of symptomatic VTE and clinical outcomes after an initially normal single proximal US result. RESULTS: Of 1295 patients, 111 (8.6%) were found to have acute deep venous thrombosis on the initial proximal US. Of the remaining 1184 patients with initially normal results on proximal US who were sampled at 3-month follow-up, 1075 patients (90.8%) had no venous thromboembolic event. Among the others, 11 (0.9%) had a subsequent imaging-confirmed venous thromboembolic event, 53 (4.5%) died (none owing to venous thromboembolism), and 45 (3.8%) did not complete follow-up. CONCLUSION: Symptomatic VTE after an initially normal single proximal US result occurred in less than 1% of this cohort. Therefore, serial proximal US is unnecessary for most of our patients, and its elimination will save time and out-of-pocket expenses.

Graduated Compression Stockings as an Adjunct to Low Dose Low Molecular Weight Heparin in Venous Thromboembolism Prevention in Surgery: A Multicentre Randomised Controlled Trial.

BACKGROUND: The evidence base upon which current global venous thromboembolism (VTE) prevention recommendations have been made is not optimal. The cost of purchasing and applying graduated compression stockings (GCS) in surgical patients is considerable and has been estimated at £63.1 million per year in England alone. OBJECTIVE: The aim was to determine whether low dose low molecular weight heparin (LMWH) alone is non-inferior to a combination of GCS and low dose LMWH for the prevention of VTE. METHODS: The randomised controlled Graduated compression as an Adjunct to Pharmacoprophylaxis in Surgery (GAPS) Trial (ISRCTN 13911492) will randomise adult elective surgical patients identified as being at moderate and high risk of VTE to receive either the current "standard" combined thromboprophylactic LMWH with GCS mechanical thromboprophylaxis, or thromboprophylactic LMWH pharmacoprophylaxis alone. To show non-inferiority (3.5% non-inferiority margin) for the primary endpoint of all VTE within 90 days, 2236 patients are required. Recruitment will be from seven UK centres. Secondary outcomes include quality of life, compliance with stockings and LMWH, overall mortality, and GCS or LMWH related complications (including bleeding). Recruitment commenced in April 2016 with the seven UK centres coming "on-line" in a staggered fashion. Recruitment will be over a total of 18 months. The GAPS trial is funded by the National Institute for Health Research Health Technology Assessment in the UK (14/140/61).

Venous Thromboembolism Requiring Extended Anticoagulation Among HIV-Infected Patients in a Rural, Resource-Constrained Setting in Western Kenya.

BACKGROUND: HIV-infected patients are at an increased risk of developing venous thromboembolism (VTE), and minimal data are available to describe the need for extended treatment. OBJECTIVE: To evaluate the frequency of and determine predictive risk factors for extended anticoagulation of VTE in HIV-infected patients in rural, western Kenya. METHODS: A retrospective chart review was conducted at the Anticoagulation Monitoring Service affiliated with Moi Teaching and Referral Hospital and the Academic Model Providing Access to Healthcare. Data were collected on patients who were HIV-infected and receiving anticoagulation for lower-limb deep vein thrombosis. The need for extended anticoagulation, defined as receiving ≥7 months of warfarin therapy, was established based on patient symptoms or Doppler ultrasound-confirmed diagnosis. Evaluation of the secondary outcomes utilized a univariate analysis to identify risk factors associated with extended anticoagulation. RESULTS: A total of 71 patients were included in the analysis; 27 patients (38%) required extended anticoagulation. The univariate analysis showed a statistically significant association between the need for extended anticoagulation and achieving a therapeutic international normalized ratio within 21 days in both the unadjusted and adjusted analysis. Patients with a history of opportunistic infections required an extended duration of anticoagulation in the adjusted analysis: odds ratio = 3.42; 95% CI = 1.04-11.32; P = 0.04. CONCLUSIONS: This study shows that there may be a need for increased duration of anticoagulation in HIV-infected patients, with a need to address the issue of long-term management. Guideline recommendations are needed to address the complexity of treatment issues in this population.

B-Mode Sonographic Assessment of the Posterior Circumflex Humeral Artery: The SPI-US Protocol-A Technical Procedure in 4 Steps.

Elite overhead athletes are at risk of vascular injury due to repetitive abduction and external rotation of the dominant arm. The posterior circumflex humeral artery (PCHA) is prone to degeneration, aneurysm formation, and thrombosis in elite volleyball players and baseball pitchers. The prevalence of PCHA-related thromboembolic complications is unknown in this population. However, the prevalence of symptoms associated with digital ischemia is 31% in elite volleyball players. A standardized noninvasive imaging tool will aid in early detection of PCHA injury, prevention of thromboembolic complications, and measurement reproducibility. A standardized vascular sonographic protocol for assessment of the proximal PCHA (SPI-US protocol [Shoulder PCHA Pathology and Digital Ischemia-Ultrasound protocol]) is presented.

Assessing the risk for development of Venous Thromboembolism (VTE) in surgical patients using Adapted Caprini scoring system.

AIM: To determine the incidence, morbidity and mortality due to Venous Thromboembolism (VTE) in surgical patients, and to assess the validity and reliability of Adapted Caprini scoring in risk stratification for VTE prophylaxis. METHODOLOGY: This was a prospective observational study in a tertiary care hospital of South India on patients who underwent both elective and emergency surgeries over a period of 9 months. An Adapted Caprini score was devised which included only the clinical criteria. The patients were scored by two persons independently at admission and followed up till the 30th post-operative day and primary and secondary end points were statistically analyzed. RESULTS: Three hundred and one patients were included and the overall incidence of VTE at 30 days was 7.3%. The risk of developing VTE was found to be significantly higher among the >8 score group as compared to 3-4 group (OR = 153.5, p < 0.001), or the 5-6 group (OR = 52.9, p < 0.001) or the 7-8 group (OR = 2.3, p = 0.002). Patients with a score of 7-8 were more likely to develop VTE as compared to 3-4 group (OR = 67.5, p < 0.001) or the 5-6 group (OR = 23.2, p < 0.001). CONCLUSION: The risk of developing VTE is less significant in the 5-6 score group compared to 7-8 or more score group. Further stratification of the highest risk groups is recommended to provide appropriate prophylaxis only to the patients with high scores, thereby reducing complications due to VTE prophylaxis.

Venous thromboembolic disease in trauma and surveillance ultrasonography.

BACKGROUND: The literature reports a wide variation in the incidence of venous thromboembolic (VTE) disease in trauma patients. The performance of routine surveillance venous duplex ultrasound of bilateral lower extremities is controversial. Furthermore, recent examinations of the national trauma databank registry have suggested that routine duplex surveillance is associated with higher deep venous thrombosis (DVT) detection rates. MATERIALS AND METHODS: We examined the incidence and risk factors for VTE disease in 2827 trauma patients admitted over a 2-y period to a state-verified level I trauma center. Detailed chart review was carried out for patients with VTE disease. We then evaluated the effects of a routine bilateral lower extremity duplex surveillance guideline on VTE detection in the subset of injury patients admitted to the trauma service. RESULTS: We found an approximately 2% incidence of venous thromboembolic disease in a mostly blunt trauma population. Amongst patients with VTE disease, the most common risk factors were obesity and significant head injury. We then evaluated the 998 patients with injury who were admitted to the trauma service 1 y before and after surveillance guideline implementation. Despite a nearly 5-fold increase in the number of duplex scans, with a substantial increase in cost, we found no significant difference in the incidence of DVT. CONCLUSIONS: Our preliminary data argue against the use of routine duplex surveillance of lower extremities for DVT in trauma patients. A larger, prospective analysis is necessary to confirm these findings.

Presence of lower limb deep vein thrombosis and prognosis in patients with symptomatic pulmonary embolism: preliminary report.

OBJECTIVES: To investigate the presence of lower limb deep vein thrombosis (DVT) and prognosis in patients with symptomatic pulmonary embolism (PE). MATERIALS AND METHODS: A total of 203 consecutive referral patients with PE were included. The distribution of DVT was evaluated with compression ultrasound (CUS), and all patients were then followed for 12 months for investigation of recurrence of venous thromboembolism (VTE) and fatal events as adverse outcome. RESULTS: The mean age of the patients was 62.8 years, and 78 (38.4%) were males. DVT was found in 118 (58.1%) patients. Of these patients, 61 (30.0%) had proximal DVT. Multivariate analysis demonstrated that active cancer, inadequate anticoagulation, leg symptoms, male gender, presence of DVT, presence of proximal DVT, and previous DVT were independent risk factors for adverse outcome. A clinical risk score ranging from 0 to 10 points was generated on the basis of multivariate regression coefficients. Receiver operating characteristic curve analysis showed that an appropriate cut-off point for discriminating between the presence and the absence of an adverse event was 4. Using this category, 166 (81.8%) patients were classified as low risk and 37 (18.2%) as high risk for adverse outcome. The adverse event rates were 6.0% for the low-risk group and 59.5% for the high-risk group. CONCLUSIONS: This study has confirmed the clinical significance of surveillance CUS in patients with a first episode of PE. Furthermore, a simple risk score on the basis of available variables can identify patients at risk of an adverse outcome in patients with PE.

Cost benefit of intermittent pneumatic compression for venous thromboembolism prophylaxis in general surgery.

AIM: In moderate to high-risk general surgical patients, the cost effectiveness of mechanical prophylaxis for venous thromboembolism (VTE) is uncertain. Therefore, we determined the costs and savings of intermittent pneumatic compression (IPC) plus graduated compression stockings (GCS). METHODS: Postoperative VTE events in the absence of prophylaxis, efficacy of prophylaxis and costs of prophylaxis have been obtained from the English literature and Medicare 2004 reimbursement schedule. RESULTS: In 1000 moderate to high risk general surgical patients, in the absence of prophylaxis, the cost of investigating and treating 72 patients with clinical suspicion of DVT and 32 with PE is calculated to be $263,779. This corresponds to a cost of $263 per surgical patient. The cost of IPC combined with TED stockings in 1000 similar patients would be $66 760, and the cost of diagnosis and treatment of the reduced numbers (69% reduction) of clinical VTE is $ 83,574 making a total of $150 344. This means a saving of $133,435 ($263,779 - $150,344) per 1000 patients. This corresponds to a saving of $113 per surgical patient. Sensitivity analysis demonstrates that despite variation in costs or efficacy for IPC plus GCS, marked savings persist. CONCLUSIONS: Prophylaxis with IPC not only prevents VTE but also saves money.