Advances in the Diagnosis of Venous Thromboembolism

Validation of the Safety and Efficacy of Apixaban as Postoperative Thromboembolism Prophylaxis for Patients with Gynecologic Malignancies

BACKGROUND

Venous thromboembolism is a preventable complication of gynecologic cancer surgery that leads to postoperative morbidity and mortality. This study compared apixaban with enoxaparin to identify whether apixaban had the same safety and efficacy for patients undergoing gynecologic cancer surgery.

METHODS

The study identified patients with a gynecologic malignancy who underwent surgery and were prescribed apixaban at discharge between June 2020 and April 2023. International Classification of Diseases 10 codes were used to identify patients who had a thromboembolism within 90 days or a bleeding event within 60 days after surgery. The rates of events for patients prescribed apixaban were compared with those for a historical cohort of patients who received enoxaparin. Fisher's exact tests were used to compare categorical variables, and t tests were used to compare continuous variables. A logistic regression was performed to compare the odds of thromboembolism between the two groups.

RESULTS

Baseline patient characteristics differed in terms of body mass index (BMI), race, route of surgery, and type of cancer. Of the 490 patients in the apixaban cohort, 12 (2.4%) had a thromboembolism compared with 3 (2.1%) of the 138 patients in the enoxaparin group (adjusted odds ratio [aOR], 1.02; 95% confidence interval [CI] 0.30-4.70; p > 0.999). The odds ratio was adjusted for BMI, age, and route of surgery. A bleeding event occurred for 1 (0.2%) of the 490 patients in the apixaban group and for 1 (0.7%) of the 138 patients in the enoxaparin group.

CONCLUSIONS

This validation study showed that apixaban is a safe and effective method of postoperative venous thromboembolism prophylaxis. The data provide support to previous data and guideline updates recommending the use of apixaban for postoperative prophylaxis.

Risk factors for hypercoagulability after laparoscopic hepatic haemangioma resection

Background

Laparoscopic hepatectomy with a small incision, light abdominal wall trauma and rapid postoperative recovery has been widely used in the surgical treatment of benign liver diseases. However, the occurrence of complications, such as deep-vein thrombosis, associated with laparoscopic techniques has raised concerns. This study aimed to investigate the factors influencing the development of a hypercoagulable state in patients following laparoscopic hepatic haemangioma resection.

Materials and Methods

Between 2017 and 2019, 78 patients to be treated by laparoscopic hepatic haemangioma resection were selected prospectively for the study. The differences in relevant clinical factors between patients with and without blood hypercoagulability at 24 h after surgery were compared, and the factors influencing the development of blood hypercoagulability after surgery were analysed.

Results

The study included 78 patients, split into the hypercoagulable group (n = 27) and nonhypercoagulable group (n = 51). Compared with patients who did not develop blood hypercoagulability, patients who did had significantly higher preoperative levels of fibrinogen (Fib), D-dimer (D-Di), fibrinogen degradation products (FDP), platelet count (PLT), low-density lipoprotein cholesterol (LDL-C) and history of hyperlipidaemia whereas high-density lipoprotein cholesterol (HDL-C) levels were significantly lower (P < 0.05.) in hypercoagulable group. Univariate and multifactorial logistic regression analyses showed that a history of hyperlipidaemia, Fib ≥3.83 g/L, D-Di ≥9.12 μg/ml, FDP ≥14.64 μg/ml, PLT ≥292 × 109/L, HDL-C ≥1.25 mmol/L and LDL-C ≥2.03 mmol/L was the most common independent risk factors for the development of a hypercoagulable state of blood in patients after laparoscopic hepatic haemangioma resection (P < 0.05).

Conclusion

For patients undergoing laparoscopic hepatic haemangioma resection, attention should be paid to the development of a hypercoagulable state in those with the risk factors described in this study.

Hemostatic parameters in patients with spinal cord injury in subacute and chronic phase of the rehabilitation

Objective: The goal of this study was to measure hemostatic markers after SCI.Design: Assesing changes in coagulation and fibrynilitic system in SCI patients in different time post injury to Cross-sectional study.Setting: Rehabilitation Department of the Bydgoszcz University Hospital, Poland from 2011 to 2017.Participants: SCI patient during acute and chronic rehabilitation (N = 88).Outcome Measures: Assesing following parameters: platelet counts and levels of D-dimer, antithrombin III (ATIII), tissue factor (TF), tissue factor pathway inhibitor (TFPI) and the inflammatory marker, C-reactive protein (CRP).Interventions: Eighty-eight SCI patients were divided into three groups based on the time elapsed from injury: group I (three weeks to three months), group II (three to twelve months) and group III (more than twelve months). All patients underwent ultrasonography (US) to detect acute or chronic recanalized deep vein thrombosis (DVT). Platelet counts and levels of D-dimer, ATIII, TF, TFPI and CRP were assessed. TF and TFPI levels were measured in the control group of forty healthy individuals without SCI, the rest of the parameters were compared to laboratory norms.Results: D-dimer levels were significantly higher in group I compared to group II (P = .0002) and group III (P < .001). Group II had higher D-dimer levels than group III (P = .032). TFPI levels were higher in group II compared with group III (P = .0041) and control group (P = .000033). TF was significantly higher in all the SCI groups compared with the control group (P < .001).Conclusions: D-dimer and TF levels were still elevated twelve months after SCI. TF levels were also elevated over 12 months after inury. The results may indicate that sub-acute and even chronic SCI patients have disturbed coagulation and fibrynolitic system.

Safety and Efficacy of Apixaban vs Enoxaparin for Preventing Postoperative Venous Thromboembolism in Women Undergoing Surgery for Gynecologic Malignant Neoplasm: A Randomized Clinical Trial

Importance

Current guidelines recommend a 28-day course of enoxaparin for thromboprophylaxis after surgery for gynecologic cancer. The high cost of this medication and the low adherence rates observed in prior studies provide an opportunity to benefit patients by demonstrating the safety of a more cost-effective, easier to use thromboprophylactic.

Objective

To investigate the safety and efficacy of an oral treatment alternative for thromboprophylaxis in postoperative patients with gynecologic cancer.

Design, Setting, and Participants

This was a patient-based, multicenter, open-label, blinded, end point, randomized clinical trial conducted May 2015 to March 2019 in outpatient and inpatient gynecologic oncology settings. Women undergoing surgery for suspected or confirmed gynecologic cancer were approached for recruitment. The trial compared rates of major bleeding and clinically relevant nonmajor bleeding events during a 90-day follow-up period in patients taking apixaban or enoxaparin for postoperative thromboprophylaxis using a modified intent-to-treat analysis. Data analysis was performed from October to December 2019.

Interventions

Women were randomized to 28 days of apixaban (2.5 mg orally twice daily) or enoxaparin (40 mg subcutaneously daily).

Main Outcomes and Measures

The primary outcome was major bleeding and clinically relevant nonmajor bleeding events. Secondary outcomes included incidence of venous thromboembolic events, adverse events, medication adherence, participant quality of life, and medication satisfaction.

Results

Of 500 women recruited for the study, 400 were enrolled and randomized (median age, 58.0 years; range, 18.0-89.0 years); 204 received apixaban and 196 received enoxaparin. Treatment groups did not differ in terms of race/ethnicity, cancer stage, or surgery modality (open vs robotic). There were no statistically significant differences between the apixaban and enoxaparin groups in terms of rates of major bleeding events (1 patient [0.5%] vs 1 patient [0.5%]; odds ratio [OR], 1.04; 95% CI, 0.07-16.76; P > .99), clinically relevant nonmajor bleeding events (12 patients [5.4%] vs 19 patients [9.7%]; OR, 1.88; 95% CI, 0.87-4.1; P = .11), venous thromboembolic events (2 patients [1.0%] vs 3 patients [1.5%]; OR, 1.57; 95% CI, 0.26-9.50; P = .68), adverse events, medication adherence, or quality of life between the groups. Participant satisfaction was significantly greater in the apixaban group with regard to ease of taking the medication (186 patients [98.9%] vs 110 patients [58.8%]; OR, 0.06; 95% CI, 0.01-0.25; P < .001) and pain associated with taking the medication (4 patients [2.1%] vs 92 patients [49.2%]; OR, 9.20; 95% CI, 2.67-31.82; P < .001).

Conclusions and Relevance

These findings suggest that oral apixaban is a potentially safe, less painful, and easier-to-take alternative to subcutaneous enoxaparin for thromboprophylaxis after surgery for gynecologic cancer. The efficacy of apixaban to prevent venous thromboembolic events is hypothesized as being equivalent.

Trial Registration

ClinicalTrials.gov Identifier: NCT02366871.

Coagulation and deep vein flow changes following laparoscopic total extraperitoneal inguinal hernia repair: a single-center, prospective cohort study

BACKGROUND AND PURPOSE

Venous thromboembolism (VTE) is a serious complication encountered in surgical practice. The purpose of this study was to identify changes in coagulation status and deep vein flow parameters, within 24 h postoperatively, for patients undergoing laparoscopic total extraperitoneal inguinal hernia repair (TEP).

METHODS

For 144 patients undergoing TEP, coagulation markers including prothrombin time (PT), partial thromboplastin time, thrombin time, D-dimer, fibrinogen, fibrin degradation products (FDP), and international normalized ratio (INR) were monitored preoperatively and in the first morning postoperatively. Echo-Doppler recordings preoperatively and again within 24 h postoperatively were completed for 23 patients to monitor lower extremity deep vein flow parameters including speed of flow (cm/s), diameter (cm), and cross-sectional area (cm²). Clinically significant VTE and other complications were recorded.

RESULTS

No significant VTE were diagnosed. Significant increases were seen in the first morning postoperatively for PT, D-dimer, FDP, and INR (P < 0.05). Stratified by age, except for those < 50 years, the ratio of value-outside-the-normal-range (VONR) for D-dimer and FDP increased significantly postoperatively for all age groups. Stratified by operation duration, a significant difference in the ratio of VONR in D-dimer was identified postoperatively between those with an operation duration < 60 min and ≥ 60 min. There were significant decreases in the iliac and common femoral vein flow velocity of the ipsilateral extremity postoperatively (P < 0.05).

CONCLUSIONS

Activated hypercoagulability and hampered lower extremity deep vein flow were observed immediately after TEP. DVT formation was more pronounced in older patients and for those with operation duration ≥ 60 min. Proper VTE risk stratification for laparoscopic inguinal hernia repair (LIHR) and prophylaxis early after LIHR should be important clinical considerations.

28 day post-operative persisted hypercoagulability after surgery for benign diseases: a prospective cohort study

BACKGROUND

Surgery for benign disease is associated with a low-risk of developing venous thromboembolism (VTE). Despite a relatively low incidence of postoperative VTE in patients after elective cholecystectomy and abdominal hernia repair there are data proving hypercoagulability in the early postoperative period. We focused on assessment of the systemic inflammatory response and coagulation status in these surgical patients after hospital discharge.

METHODS

Prospectively, patients who underwent surgery for benign disease were included. Two hundred sixteen patients were enrolled - 90 patients in laparoscopic cholecystectomy (LC) group and 126 patients in hernia surgery (HS) group. Risk assessment of VTE according to the Caprini risk assessment model was performed in all patients. Prevalence of VTE in postoperative period was observed. Markers of systemic inflammatory response (IL-6, CRP, α-1-acid glycoprotein, transferrin) and coagulation markers (PLT, fibrinogen, prothrombin fragment F1 + 2 and D-dimer) were measured before surgery, on 7-10th postoperative day and on 28-30th postoperative day.

RESULTS

Clinically apparent deep vein thrombosis was diagnosed in only one patient - 0.46%. Statistically significant elevation of inflammatory markers IL-6, CRP and α-1-acid glycoprotein (p < 0.001; all) were proved in both groups of patients on 7-10th postoperative day. Statistically significant elevation of coagulation markers PLT, fibrinogen, prothrombin fragment F1 + 2 and D-dimer (p < 0.001; all) were proved in LC and HS groups on 7-10th postoperative day. No statistical difference was observed in IL-6, CRP and α-1-acid glycoprotein levels a month after surgery as compared with preoperative levels within each group. Statistically significant elevation of fibrinogen and prothrombin fragment F1 + 2 levels (p < 0.001; both) persisted on 28-30th postoperative day in both groups. Persisted elevation of D-dimer levels was proved only in HS group (p < 0.001), not in LC group (p = 0.138), a month after surgery.

CONCLUSIONS

Activated systemic inflammatory response and hypercoagulable condition were verified in patients after laparoscopic cholecystectomy and hernia surgery after their hospital discharge. Hypercoagulability persisted even a month after surgery. Nevertheless, we observed very low prevalence of clinically apparent VTE in patients with in-hospital postoperative VTE prophylaxis.

TRIAL REGISTRATION

Trials of the Czech Ministry of Health No. RVO-VFN64165 and NT 13251-4 .

Predicting perioperative venous thromboembolism in Japanese gynecological patients

OBJECTIVE

To develop a convenient screening method that can predict perioperative venous thromboembolism (VTE) and identify patients at risk of fatal perioperative pulmonary embolism (PE).

METHODS

Patients hospitalized for gynecological abdominal surgery (n = 183) underwent hematology tests and multidetector computed tomography (MDCT) to detect VTE. All statistical analyses were carried out using the SPSS software program (PASWV19.0J).

RESULTS

The following risk factors for VTE were identified by univariate analysis: plasmin-alpha2-plasmin inhibitor complex (PIC), thrombin-antithrombin III complex (TAT), and prolonged immobility (all p<0.001); age, neoadjuvant chemotherapy (NAC), malignancy, hypertension, past history of VTE, and hormone therapy (all p<0.01); and hemoglobin, transverse tumor diameter, ovarian disease, and menopause (all p<0.05). Multivariate analysis using these factors revealed that PIC, age, and transverse tumor diameter were significant independent determinants of the risk of VTE. We then calculated the incidence rate of perioperative VTE using PIC and transverse tumor diameter in patient groups stratified by age. In patients aged ≤40 years, PIC ≥1.3 µg/mL and a transverse tumor diameter ≥10 cm identified the high-risk group for VTE with an accuracy of 93.6%. For patients in their 50 s, PIC ≥1.3 µg/mL identified a high risk of VTE with an accuracy of 78.2%. In patients aged ≥60 years, a transverse tumor diameter ≥15 cm (irrespective of PIC) or PIC ≥1.3 µg/mL identified the high-risk group with an accuracy of 82.4%.

CONCLUSIONS

We propose new screening criteria for VTE risk that are based on PIC, transverse tumor diameter, and age. Our findings suggest the usefulness of these criteria for predicting the risk of perioperative VTE and for identifying patients with a high risk of fatal perioperative PE.

Respiratory review of 2013: pulmonary thromboembolism

Pulmonary embolism (PE), which can originate as a consequence of deep vein thrombosis (DVT), is the most frequent and potentially fatal venous thromboembolic event. Despite the fact that the incidence of venous thromboembolism (VTE) in Asians is lower than that in the Western populations, a recent epidemiologic study demonstrates an increasing incidence of VTE in the Korean population. Anticoagulants, including low molecular weight heparin (LMWH) and vitamin K antagonist (VKAs), have been the main treatments for PE, however, recently new oral anticoagulants (NOACs) were introduced. We will review how well patients with PE can be managed with the existing anticoagulants and NOACs along with the time span of treatment, which still pose some challenges for clinicians.

Comparison of empirical estimate of clinical pretest probability with the Wells score for diagnosis of deep vein thrombosis

Wells score has been validated for estimation of pretest probability in patients with suspected deep vein thrombosis (DVT). In clinical practice, many clinicians prefer to use empirical estimation rather than Wells score. However, which method is better to increase the accuracy of clinical evaluation is not well understood. Our present study compared empirical estimation of pretest probability with the Wells score to investigate the efficiency of empirical estimation in the diagnostic process of DVT. Five hundred and fifty-five patients were enrolled in this study. One hundred and fifty patients were assigned to examine the interobserver agreement for Wells score between emergency and vascular clinicians. The other 405 patients were assigned to evaluate the pretest probability of DVT on the basis of the empirical estimation and Wells score, respectively, and plasma D-dimer levels were then determined in the low-risk patients. All patients underwent venous duplex scans and had a 45-day follow up. Weighted Cohen's κ value for interobserver agreement between emergency and vascular clinicians of the Wells score was 0.836. Compared with Wells score evaluation, empirical assessment increased the sensitivity, specificity, Youden's index, positive likelihood ratio, and positive and negative predictive values, but decreased negative likelihood ratio. In addition, the appropriate D-dimer cutoff value based on Wells score was 175 μg/l and 108 patients were excluded. Empirical assessment increased the appropriate D-dimer cutoff point to 225 μg/l and 162 patients were ruled out. Our findings indicated that empirical estimation not only improves D-dimer assay efficiency for exclusion of DVT but also increases clinical judgement accuracy in the diagnosis of DVT.

The great deception: tranexamic acid and extensive pulmonary emboli

Pulmonary embolism (PE) is a common and life-threatening condition. The British Thoracic Society PE guidelines state that PE is reliably excluded in patients with low-intermediate clinical probability and a negative D-dimer. We are reporting the case of a 47-year-old lady, taking tranexamic acid for menorrhagia, who presented with shortness of breath and was diagnosed with extensive bilateral PE. She had a low clinical risk of PE as determined by her Wells score, and a subsequent negative D-dimer. This patient's D-dimer value of 15 ng/ml (HemosIL DD HS assay) was the lowest associated with any CT pulmonary angiogram (n=1645) recorded at our trust over a 2-year period. This lady was successfully treated with a heparin infusion and warfarin. No further thromboembolic events had occurred by 18-month follow-up. To our knowledge, this is the first case report to describe tranexamic acid causing an extremely low false-negative D-dimer masking PE.

[Thromboembolic events in malignant diseases]

There is a bidirectional connection between tumors and thrombosis. On one hand, thromboembolic events are more frequent in cases of malignancies, on the other hand, proliferation of tumor cells, progression of the malignant process and metastasis formation are facilitated by the activation of the hemostatic system. Thromboembolic events are associated with a worse prognosis in case of patients with malignant diseases. Thromboembolism is the second most frequent cause of death in patients with malignant tumors. Mortality is twice as high in patients with thromboembolism compared to those without it. The incidence of thromboembolism shows an increasing tendency. There has been a 28% increase among hospitalized cancer patients between 1995 and 2003. One reason is that the new anti-tumor agents have more pronounced prothrombotic activity than those of traditional chemotherapeutic drugs. Assessment of the thrombotic risk of cancer patients becomes more important. Several guidelines have been published concerning the prevention and treatment of thromboembolism in patients with malignancy. The risk of thrombosis is influenced not only by the type of malignancy but there are also large individual differences. Furthermore, the risk of thrombosis changes during the disease process in the same patient. Perioperative thromboprophylaxis is a very important issue considering oncologic surgery. Thromboprophylaxis of oncologic patients has a high significance in respect of morbidity and mortality. However, thromboprophylaxis may also cause serious complications thus the correct risk assessment of cancer patients is very important.

Wells' prediction rules for pulmonary embolism: valid in all clinical subgroups?

Pulmonary embolism is major cause of hospital death. Clinical prediction rules such as Wells' prediction rules can help in selection of at-risk patients who need further testing for pulmonary embolism. We evaluated the usefulness of such criteria for detection of patients with diagnosed pulmonary embolism. Patients enrolled in National Research Institute of Tuberculosis and Lung Disease (NRITLD) deep venous thrombosis (DVT) registry were evaluated and those with objective data about presence or absence of pulmonary embolism were selected for this study. Diagnosis of pulmonary embolism was based on computed tomography pulmonary angiography (CTPA). We calculated the embolic burden in those with CTPA-confirmed pulmonary embolism. Eighty-six patients entered the study (58 males, 28 females, mean age = 54.39 ± 1.74 years). Fifty-four cases had coexisting pulmonary embolism (embolic burden score: 10.77 ± 1.181). Embolic burden score was correlated to presence of massive pulmonary embolism (Pearson rho: 0.43, P = 0.002). There was no association between Wells' pulmonary embolism score and the occurrence of pulmonary embolism (Spearman's rho: 0.085, P = 0.51). Dividing the patients into two, or three, risk groups according to Wells' model did not reveal an association with occurrence of pulmonary embolism either (P = 0.99 and P = 0.261, respectively). Tachycardia and hemoptysis were the only parameters from the Wells' pulmonary embolism score correlated to presence of pulmonary embolism (Spearman's rho: 0.373, P < 0.000 and Spearman's rho: 0.297, P = 0.005, correspondingly). Wells' pulmonary embolism score could not predict the occurrence of pulmonary embolism in DVT patients suspected of having coexisting pulmonary embolism. Until further studies shed light on this patient subset, overreliance on Wells' prediction rules as the solo decision making tool should be cautioned.

Multimodality imaging of the peripheral venous system

The purpose of this article is to review the spectrum of image-based diagnostic tools used in the investigation of suspected deep vein thrombosis (DVT). Summary of the experience gained by the author as well as relevant publications, regarding vein imaging modalities taken from a computerized database, was reviewed. The imaging modalities reviewed include phlebography, color Doppler duplex ultrasonography (CDDUS), computerized tomography angiography (CTA) and venography (CTV), magnetic resonance venography (MRV), and radionuclide venography (RNV). CDDUS is recommended as the modality of choice for the diagnosis of DVT. A strategy combining clinical score and D-dimer test refines the selection of patients. Phlebography is reserved for discrepant noninvasive studies.

Pulmonary embolism presenting as flank pain: a case series

BACKGROUND

Pulmonary embolism (PE) is a potentially fatal disease that can be effectively treated once diagnosed. Due to insidious and often cryptogenic presentations, the diagnosis of this disease can easily elude clinicians. Over the last several years the use of computed tomography (CT) scanning has improved the clinician's ability to diagnose PE. In addition, the widespread use of CT to investigate other complaints such as flank and abdominal pain could theoretically result in radiographic findings not previously identified that could point to the diagnosis of PE. The current case series reveals the unexpected and initially unrecognized CT finding of a pulmonary infarct in two patients presenting with flank pain; a third patient presented with flank pain and was also found to have a PE.

OBJECTIVE

We describe three cases of patients who presented to the Emergency Department with flank pain who were diagnosed with pulmonary embolism.

CASE REPORTS

The cases reported here discuss patients who presented with flank pain and were ultimately diagnosed with PE. In the first two cases, the patients had incidental findings of pulmonary infiltrates on abdominal CT scans, which prompted further diagnostic investigation. In the third case, the patient had risk factors for PE and presented with flank pain and the diagnosis was quickly made by CT imaging.

CONCLUSION

Physicians should consider pulmonary embolism in the differential diagnosis of patients with isolated flank pain. Additionally, unexpected pulmonary findings on abdominal CT scans may help suggest the diagnosis of PE in the appropriate clinical setting.

Thromboembolic disease after total knee replacement: experience of 5100 cases

The aim of the study was to quantify the incidence and timing of venous thromboembolic events (VTE) after total knee replacement (TKR). Data from 5100 consecutive TKRs performed over 10 years were prospectively collected. Cases were reviewed to identify thromboprophylaxis given, the diagnosis of VTE, treatment and adverse outcomes. There were 3 deaths (0.059%) from pulmonary embolism (PE). Of 123 VTEs identified, 55 had PE, 17 had above knee deep vein thrombosis (DVT), 28 had calf DVT and 14 had been incorrectly coded as VTE. There was considerable inappropriate treatment of calf DVT with resultant morbidity. There was an increase in diagnosis of PE between days 1 and 5 post surgery in the later part of the study, corresponding with increasing use of CT Pulmonary Angiography. Increasing diagnosis of PE may be due to detection of embolic debris from surgery due to greater vigilance rather than post-operative thromboembolism. Death from PE is rare following TKR.

Perioperative d-dimer levels in patients with musculoskeletal tumors

BACKGROUND

D-dimer (DD) levels have been reported as a sensitive but non-specific indicator for deep vein thrombosis (DVT) and pulmonary embolism (PE). Few reports have examined perioperative DD levels in musculoskeletal tumor.

MATERIALS/METHODS

Subjects comprised 77 patients who had undergone oncological resection of musculoskeletal tumor. DD levels were assessed preoperatively and on postoperative days 1 and 7. Multidetector-row computed tomography (MD-CT) was performed to detect DVT/PE for cases with DD level >10.0 microg/ml.

RESULTS

Mean preoperative DD level was 0.84 microg/ml. Significant elevation of postoperative DD levels was confirmed. DD levels were significantly changed by various clinical conditions, such as malignancy, age and prosthetic reconstruction. In 4 of 5 cases with postoperative DD levels >10.0 microg/ml, DVT/PE was detected.

CONCLUSION

Activation of the coagulation system by surgery and heterogeneity of DD levels under various clinical conditions in musculoskeletal tumor patients were suggested.

Twelve tips for teaching avoidance of diagnostic errors

BACKGROUND

Despite an increasing emphasis on patient safety on the part of healthcare systems worldwide, diagnostic error remains common. Errors frequently result in significant clinical consequences and persist despite remarkable advances in diagnostic technology. Most medical students and physician trainees receive little instruction regarding both the root causes of diagnostic errors and how to avoid such errors.

AIMS

This installment of the '12 tips' series discusses how to familiarize the learner with the cognitive underpinnings of diagnostic error. It also describes how to teach several approaches to the diagnostic process that may lessen the likelihood of error.

METHODS

Specific educational practices are discussed in detail. Emphasis is placed on describing meta-cognitive techniques, promoting the value of the clinical examination, and employing simple diagnostic strategies, including 'diagnostic time-outs' and the practice of 'worst-case scenario' medicine.

CONCLUSIONS

Clinical educators may help learners avoid diagnostic errors by employing several of the educational techniques described herein.

Computerised tomography for the detection of pulmonary emboli in intensive care patients--a retrospective cohort study

Pulmonary emboli are frequently considered as a cause for respiratory deterioration in intensive care unit (ICU) patients, however empirical observation suggests that computerised tomographic (CT) angiography is infrequently positive after the first 24 hours. This study aimed to determine the rate and risk factors for detection of pulmonary emboli by CT angiography in ICU patients. All patients undergoing CT angiography > 24 hours after ICU admission for respiratory deterioration from April 2000 until January 2004 were included. The positivity rate for pulmonary emboli was determined and risk factors analysed. Seven (6%) out of 113 CT angiograms were positive for pulmonary emboli. All were found in trauma patients. Comparing positive to negative scans, predefined risk factors including head injury (5/7 positive scans, 71% vs. 23/106 negative scans, 22%, P = 0.005), spine injury with neurological impairment (4/7, 57% vs. 9/106, 8%, P = 0.002) and lower limb injury (3/7, 43% vs. 12/106, 9%, P = 0.039) were significantly more frequent in patients with positive scans. Deep vein thrombosis prophylaxis was employed less frequently prior to a positive scan (in 3/7, 43% patients with positive scans vs. 91/106, 86% patients with negative scans P = 0.015). Only the predefined risk factors were independently associated with positive CT angiography on limited logistic regression (OR 24.7 per risk factor, 95% CI 2.38 to 255.1, P = 0.007). Pulmonary emboli were infrequently diagnosed using CT angiography in ICU patients admitted for more than 24 hours and found only in patients with recognised risk factors.

Combined arterial and venous whole-body MR angiography with cardiac MR imaging in patients with thromboembolic disease--initial experience

The objective was to assess the feasibility of a combined arterial and venous whole-body three-dimensional magnetic resonance (MR) angiography, together with a cardiac MR examination, in patients with arterial thromboembolism. Ten patients with arterial thromboembolism underwent a contrast-enhanced whole-body MR examination of the arterial and venous vessels, followed by a cardiac MR examination on a separate occasion within 24 h. All examinations were performed on a 1.5-T MR scanner. For both arterial and venous MR angiography only one injection of contrast agent was necessary. The cardiac imaging protocol included dark-blood-prepared half-Fourier acquisition single-shot turbo-spin-echo sequences, fast steady-state free precession cine sequences, T2-weighted turbo-spin-echo sequences and inversion recovery gradient-echo fast low-angle-shot sequences after injection of contrast agent. MR imaging revealed additional clinically unknown arterial thromboembolisms in four patients. The thoracic aorta was depicted as embolic source in four patients, while deep vein thrombosis (DVT) was found in one patient as the underlying disease. Unsuspected infarction of parenchymal organs was detected by MRI in two patients. An unknown additional DVT was found in one patient. Four patients were considered to have arterial emboli of cardiac origin. In conclusion, acquisition of arterial and venous MR angiograms of the entire vascular system combined with cardiac MR imaging is a most comprehensive and valuable strategy in patients with arterial thromboembolism.

The effects of race/ethnicity and sex on the risk of venous thromboembolism

PURPOSE OF THE REVIEW

Recently, studies on large diverse populations have described important ethnic/racial differences in venous thromboembolism incidence, and sex has been reported as an important predictor of recurrence. We review the influence of race/ethnicity and sex on venous thromboembolism, concentrating on articles from 2005 to 2007.

RECENT FINDINGS

Most studies found that women have a 40-400% lower risk of recurrent venous thromboembolism than men. Studies of ethnicity/race on risk provide strong evidence that African-American patients are the highest risk group for first-time venous thromboembolism, while Hispanic patients' risk is about half that of Caucasians. African-Americans and Hispanics have a higher risk of recurrence than Caucasians, but sex and the type of index venous thromboembolism event seem to play a role in this risk. Asian/Pacific Islanders have a markedly lower risk of first-time and cancer-associated venous thromboembolism. There is little difference in incidence in African-Americans, Hispanics, and Caucasians diagnosed with cancer. Sex does not seem to be associated with risk in cancer patients.

SUMMARY

Sex and race/ethnicity are important factors in the risk of first-time and recurrent venous thromboembolism and need to be included as risk assessment and diagnostic prediction tools are developed or updated.