Accuracy of compression ultrasound in screening for deep venous thrombosis in acutely ill medical patients

Development and evaluation of the focused assessment of sonographic pathologies in the intensive care unit (FASP-ICU) protocol

Background

The use of ultrasonography in the intensive care unit (ICU) is steadily increasing but is usually restricted to examinations of single organs or organ systems. In this study, we combine the ultrasound approaches the most relevant to ICU to design a whole-body ultrasound (WBU) protocol. Recommendations and training schemes for WBU are sparse and lack conclusive evidence. Our aim was therefore to define the range and prevalence of abnormalities detectable by WBU to develop a simple and fast bedside examination protocol, and to evaluate the value of routine surveillance WBU in ICU patients.

Methods

A protocol for focused assessments of sonographic abnormalities of the ocular, vascular, pulmonary, cardiac and abdominal systems was developed to evaluate 99 predefined sonographic entities on the day of admission and on days 3, 6, 10 and 15 of the ICU admission. The study was a clinical prospective single-center trial in 111 consecutive patients admitted to the surgical ICUs of a tertiary university hospital.

Results

A total of 3003 abnormalities demonstrable by sonography were detected in 1275 individual scans of organ systems and 4395 individual single-organ examinations. The rate of previously undetected abnormalities ranged from 6.4 ± 4.2 on the day of admission to 2.9 ± 1.8 on day 15. Based on the sonographic findings, intensive care therapy was altered following 45.1% of examinations. Mean examination time was 18.7 ± 3.2 min, or 1.6 invested minutes per detected abnormality.

Conclusions

Performing the WBU protocol led to therapy changes in 45.1% of the time. Detected sonographic abnormalities showed a high rate of change in the course of the serial assessments, underlining the value of routine ultrasound examinations in the ICU.

Trial registration The study was registered in the German Clinical Trials Register (DRKS, 7 April 2017; retrospectively registered) under the identifier DRKS00010428.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03811-2.

Endovascular and medical therapy of May-Thurner syndrome: Case series and scoping literature review

INTRODUCTION

May-Thurner syndrome has been recognized as a cause of chronic venous insufficiency and a trigger for venous thromboembolism. There is no consensus about the definition, diagnosis, and therapeutic approach. We are aiming to describe its characteristics and a scoping literature review.

METHODS

A retrospective review of patients with May-Thurner syndrome from March 2010 to May 2018 and scoping literature review were made.

RESULTS

Seven patients were identified. All patients were female with a median age of 36 (20-60) years. The median time from the first symptom to diagnosis was 3.41 (0.01-9) years. The primary clinical presentation was post-thrombotic syndrome (4 patients). Six patients had at least one risk factor for deep venous thrombosis. All patients underwent angioplasty with stent; patients with acute deep venous thrombosis, furthermore mechanic thrombectomy with or without catheter-directed thrombolysis were done. There were three complications (one patient, lymphedema, and two venous stent thrombosis). Scoping review results were descriptively summarized.

CONCLUSION

May-Thurner syndrome has a varied spectrum of clinical presentation, and clinical awareness is paramount for diagnosis. Its principal complication is the post-thrombotic syndrome, which is associated with high morbidity. There is no consensus on the antithrombotic treatment approach.

Deep Vein Thrombosis and Pulmonary Embolism Among Patients With a Cryptogenic Stroke Linked to Patent Foramen Ovale-A Review of the Literature

Background: Venous thromboembolism (VTE) can occur simultaneously with a cryptogenic stroke (CS) linked to patent foramen ovale (PFO), given paradox thromboembolism as potential stroke cause. However, little is known on the frequency of concomitant VTE and CS. We aimed to review the literature on the frequency of VTE in patients with CS linked to PFO (primary aim) and of ischemic stroke (IS) among patients with pulmonary embolism (PE) (secondary aim).

Methods: We performed a Medline search for cohort studies, written in English, with the following characteristics: (a) enrolling patients hospitalized for an acute ischemic stroke undergoing a work-up for deep venous thrombosis (DVT) and/or PE. To be included in this review, a study had to have at least a subgroup of patients with PFO; (b) the time interval between the index stroke and the work-up had to be within 40 days and the studies had to differentiate between DVT and PE. For the secondary aim, studies had to include patients with acute PE, known PFO-status and routine brain imaging on admission or within 1 year.

Results: We found eight studies reporting on the frequency of VTE after an acute CS linked to PFO. Concerning DVT, the reported frequency ranged between 7 and 27%; concerning PE, it lied between 4.4 and 37%. Six studies assessed the frequency of ischemic brain lesions among patients with an acute PE. In all studies, the presence of PFO was associated with ischemic brain lesions, both at baseline and follow-up.

Conclusion: VTE can be detected in patients with CS linked to PFO. While –based on the presented literature–routine screening for VTE in patients with CS linked to PFO does not appear justified, history taking, and clinical exam should consider concomitant VTE. Whenever clinically suspected, the threshold to trigger ancillary testing for VTE should be low. Among patients with an acute PE and PFO, vigilance for new neurologic deficits should be increased, with a low threshold for brain imaging.

D-dimer as a stand-alone test to rule out deep vein thrombosis

BACKGROUND

Current guidelines recommend the use of clinical decision rules, such as Wells score, in combination with D-dimer to assess the need for objective imaging to rule out deep vein thrombosis (DVT). However, the clinical decision rule has limitations, and use of D-dimer as a stand-alone test has been suggested.

OBJECTIVE

We aimed to assess the safety and efficiency of D-dimer as a stand-alone test to rule out DVT in outpatients referred with suspected DVT.

METHODS

We collected data from consecutive outpatients referred to our hospital with suspected DVT in 2008-2018. D-dimer levels were analyzed using STA® Liatest® D-Di assay. D-dimer as a stand-alone test was theoretically applied in retrospect, and the number of misdiagnosed events were estimated as if such an approach had been initially used. All patients were followed for three months.

RESULTS

Of 1765 included patients, 293 (16.6%) were diagnosed with DVT. A total of 491 patients (27.8%) had a negative D-dimer (<500 ng/mL). Of these, nine were diagnosed with DVT, yielding a failure rate for D-dimer as a stand-alone test of 1.8% (95% CI 0.8%-3.5%). The majority of the misdiagnosed patients had distal DVT. In analyses restricted to proximal DVTs, the failure rate was 0.6% (95% CI 0.1%-1.8%). D-dimer as a stand-alone approach reduced the proportion of required ultrasounds from 81.8% to 72.2%.

CONCLUSION

D-dimer as a stand-alone test may be safe for excluding proximal DVT and reduce the proportion of required ultrasounds. Prospective management studies are needed to confirm our findings.

The role of cardiovascular ultrasound in diagnosis and management of pulmonary embolism

The diagnosis of acute pulmonary embolism (PE) is one of the most important problems in medical emergencies. Commonly accepted criterion for diagnosis of deep venous thrombosis is the lack of vein compressibility assessed by Compression UltraSonography. Echocardiography represents an easily available and reliable imaging technique in the clinical setting of hemodynamic instability and in the direct visualization of thromboembolic masses in the right heart chambers. Moreover, echocardiography is useful for prognostic stratification after acute PE as right ventricular dysfunction is the most important predictor of mortality in this context. This review aims to highlight usefulness, potentialities and perspectives of standard and advanced echocardiography in evaluating patients affected by PE.

Ethnicity as an independent predictive factor for the results of computed tomography pulmonary angiography and ultrasonography of the lower limbs

BACKGROUND

Asians, Pacific Islanders and Maori have significantly lower rates of venous thromboembolism (VTE) compared to Europeans, but its clinic implication regarding diagnosis and prevention is unclear.

AIMS

To investigate if ethnicity affects the yield of computed tomography pulmonary angiography (CTPA) and ultrasonography of the lower limbs.

METHODS

Data previously collected for 523 patients from another study were used to analyse the effect of ethnicity on the results of CTPA; 1587 consecutive ultrasonography of lower limbs was retrospectively analysed according to ethnicity. The Wells score was retrospectively calculated to determine the pretest probability of VTE.

RESULTS

The positive rates of CTPA were 23.3% for European patients and 9.3% for non-European patients. The rate ratio was 2.50 (confidence interval [CI] 1.27-4.95). European patients were 2.5 times more likely to have a positive scan result than non-Europeans, given same pretest probability. There was a larger difference among patients with low and moderate pretest probability with a rate ratio of 4.27 (CI 1.62-11.3). The positive rates of ultrasound scans (USS) among European patients were 16.6 and 9.0% for non-European patients. Rate ratio was 1.85 (CI 1.27-4.95). The difference was also more significant amongst patients with low and moderate pretest probability. The rate ratio was 2.31 (CI 1.38-3.86) for European patients compared to non-European patients.

CONCLUSION

Given the same pretest probability according to the Wells score, European patients had significantly higher positive rates of CTPA and ultrasonography of the lower limbs than non-European patients. Further prospective studies are required to confirm our findings and establish an appropriate pretest assessment tool for non-European patients.

Incidentally found pulmonary embolism: what's the clinician to do?

Incidental pulmonary embolism (IPE) is a management challenge for the unsuspecting clinician. Patients with IPE frequently have signs or symptoms that are unrecognized as PE related, and their clots occur predominantly in the proximal pulmonary vasculature. There is uniformity in recommending anticoagulation for patients with IPE proximal to the subsegmental pulmonary vasculature, but prospective data are not currently available to guide the duration of therapy in this population. Several studies suggest that outcomes, including recurrence, mortality, and bleeding, are similar for patients with IPE and suspected PE, especially among those who also have cancer. Patients with isolated incidental subsegmental pulmonary embolism (ISSPE) are particularly challenging because some studies suggest that they can be managed without anticoagulation. Therefore, an algorithm is proposed to guide the evaluation and treatment of patients with ISSPE.

Analysis of the accuracy of the Wells scale in assessing the probability of lower limb deep vein thrombosis in primary care patients practice

Background

The clinical picture of deep vein thrombosis (DVT) is nonspecific. Therefore assessment of the probability of occurrence of DVT plays a very important part in making a correct diagnosis of DVT.

The aim of our prospective study was to assess the accuracy of the Wells scale in primary care setting in diagnostic procedure of suspected deep vein thrombosis.

Methods

In the period of 20 - months (from 2007 to 2009) a group of residents from one of the urban districts of Warsaw, who reported to family doctors (22 primary care physicians were involved in the study) with symptoms of DVT were assessed on the probability of occurrence of deep vein thrombosis using the Wells scale. Family doctors were aware of symptoms of DVT and inclusion patients to this study was based on clinical suspicion of DVT.

Patients were divided into three groups, reflecting probability of DVT of the lower limbs.

To confirm DVT a compression ultrasound (CUS) test was established.

We analyzed the relationship between a qualitative variable and a variable defined on an original scale (incidence of DVT versus Wells scale count) using the Mann–Whitney test. Chi-square test compared rates of DVT events in all clinical probability groups.

Patient were follow up during 3 months in primary care setting.

Results

In the period of 20 months (from 2007 to 2009) a total number of 1048 patients (male: 250 , female: 798 mean age: 61.4) with symptoms suggestive of DVT of the lower extremities entered the study. Among the 100 patients classified in the group with a high probability of DVT of the lower extremities, 40 (40%) patients (proximal DVT - 13; distal DVT - 27) were diagnosed with it (95% CI [30.94% -49.80%]). In the group with a moderate probability consisting of 302 patients, DVT of the lower extremities was diagnosed in 19 (6.29%) patients (95% CI [4.06% -9.62%]), (proximal DVT – 1; distal DVT - 18). Of the 646 patients with a low probability of DVT of the lower extremities distal DVT was diagnosed in 1 (0.15%) patient (95% CI [0.03% -0.87%]).

Conclusion

The Wells scale used in primary care setting demonstrated a high degree of accuracy.

Bedside ultrasonography-Applications in critical care: Part II

Point of care ultrasonography, performed by acute care physicians, has developed into an invaluable bedside tool providing important clinical information with a major impact on patient care. In Part II of this narrative review, we describe ultrasound guided central venous cannulation, which has become standard of care with internal jugular vein cannulation. Besides improving success rates, real-time guidance also significantly reduces the incidence of complications. We also discuss compression ultrasonography - a quick and effective bedside screening tool for deep vein thrombosis of the lower extremity. Abdominal ultrasound offers vital clues in the emergency setting; in the unstable trauma victim, a focused examination may provide immediate answers and has largely superseded diagnostic peritoneal lavage in diagnosing intraperitoneal bleed. From estimation of intracranial pressure to transcranial Doppler studies, ultrasound is becoming increasingly relevant to neurocritical care. Ultrasound may also help with airway management in several situations, including percutaneous tracheostomy. Clearly, bedside ultrasonography has become an indispensable part of intensive care practice – in the rapid assessment of critically ill-patients as well as in enhancing the safety of invasive procedures.

Deep venous thrombosis after knee arthroscopy: a systematic review and meta-analysis

PURPOSE

To establish a contemporary literature-based estimate of the incidence of deep venous thrombosis (DVT) after knee arthroscopic surgery.

METHODS

We performed a systematic review and meta-analysis of the English language literature to assess the efficacy of prophylaxis to prevent DVT after knee arthroscopic surgery. Only randomized controlled trials (RCTs) or prospective studies were considered. Studies were excluded if they were not original prospective studies concerning DVT detected by imaging after knee arthroscopic surgery. We calculated pooled proportions of postoperative DVT and proximal DVT.

RESULTS

Nine prospective uncontrolled studies and 4 RCTs were retrieved. Within them, the populations given low-molecular-weight heparin (LMWH) to prevent DVT had a 0.1% to 11.9% incidence of DVT, with an overall 36 DVTs identified (4 proximal), averaging 1.8%. One hundred thirty-six DVTs (29 proximal) were indicated in the populations without prophylaxis, and the DVT incidence varied from 1.8% to 41.2%, averaging 6.8%. Of the RCTs, the pooled risk ratio for DVT to develop was 0.180 (range, 0.065 to 0.499) for those who had LMWH as prophylaxis. An absolute risk reduction of 1.2%--from 1.5% to 0.3%--for the development of proximal DVT was observed.

CONCLUSIONS

Compared with patients who did not receive prophylaxis, the pooled risk ratio for the development of DVT was 0.18 for those who had LMWH prophylaxis. The incidence of proximal DVT is very low after arthroscopic surgery regardless of receiving prophylaxis (4 of 2,184) or not (29 of 1,814). The rate of proximal DVT in total DVT occurrence can be markedly reduced from 21.3% (29 of 136) to 11.1% (4 of 36).

LEVEL OF EVIDENCE

Level IV. This study is a meta-analysis of RCTs and a systematic review of Level IV studies.

The utility of screening for asymptomatic lower extremity deep venous thrombosis during inflammatory bowel disease flares: a pilot study

BACKGROUND

Asymptomatic deep vein thrombosis (DVT) occurs in up to 11% of medical inpatients. The incidence of asymptomatic DVT among patients with inflammatory bowel disease (IBD) is unknown but may be even higher. D-dimer is effective for DVT screening, but its utility has not been studied in the IBD population.

METHODS

Hospitalized and ambulatory patients with IBD during flares were recruited between 2009 and 2011. Those with clinical symptoms of venous thromboembolism or previous venous thromboembolism were excluded. We determined the prevalence of DVT among asymptomatic subjects using lower extremity Doppler ultrasound and assessed the performance characteristics of the D-dimer in this high-risk study population.

RESULTS

We enrolled 101 hospitalized and 49 ambulatory patients with IBD during active flares. There were no cases of proximal DVT detected by lower extremity Doppler ultrasound. The 95% confidence interval (CI) for the rate of proximal DVT was 0% to 2%. D-dimer was elevated in 60% of subjects without DVT, occurring more frequently among hospitalized than ambulatory subjects [89% versus 65%, P = 0.01; adjusted odds ratio (aOR), 4.16, 95% CI, 1.58-10.9]. Other predictors of elevated D-dimer were incremental decade in age (aOR, 1.97; 95% CI, 1.24-3.14); ulcerative colitis versus Crohn's disease diagnosis (aOR, 3.38; 95% CI, 1.29-8.84); and every 10-unit increase in C-reactive protein (aOR, 1.33; 95% CI, 1.09-1.62).

CONCLUSION

From this pilot study, there appears to be low prevalence of asymptomatic DVTs among patients with IBD during flares. The high prevalence of elevated D-dimer in DVT-negative patients limits its utility in IBD.

A new D-dimer cutoff in bedridden hospitalized elderly patients

Asymptomatic deep vein thrombosis (DVT) and pulmonary embolism are leading causes of morbidity following the hospitalization of elderly people. The diagnosis of DVT is supported by the D-dimer laboratory assay. The concentration of D-dimer increases in patients with DVT, but may be high in other conditions too (i.e. cancer, infections and inflammation). Old age coincides with a physiological increase in D-dimer values, and that is why D-dimer assay in the elderly is characteristically highly sensitive but scarcely specific. The aim of our study was to explore the reliability of different D-dimer cutoffs for the diagnosis of asymptomatic DVT in a population of bedridden hospitalized elderly patients. We studied 199 patients who were a mean 86.3 ± 6.7 years old. All participants underwent lower limb Doppler ultrasound (DUS) and D-dimer venous blood sampling on admission. In our cohort, the usual cutoff proved highly sensitive (100%), but its specificity was very poor (20.1%). To find a higher cutoff that could improve the method's specificity, we analyzed our data using a receiver operating characteristic curve analysis. The resulting D-dimer cutoff of 492 μg/l enabled us to retain the same sensitivity while improving the test's specificity to 39.1%, with a consequent improvement in its positive predictive value and accuracy. In addition to improving the method's reliability, this result may be helpful in clinical practice, in both medical wards and nursing homes. By adopting a cutoff of 492 μg/l, clinicians could significantly increase the proportion of older patients in whom DVT can be safely ruled out, reducing referrals for DUS and administration of heparin, with consequent clinical, practical and economic advantages.

Effect of a public awareness campaign on the incidence of symptomatic objectively confirmed deep vein thrombosis: a controlled study

BACKGROUND

Although there have been attempts to raise public awareness about deep vein thrombosis (DVT), their influence on identifying confirmed cases is unknown.

OBJECTIVE

To determine the effect and its duration of a public awareness campaign about venous thromboembolism.

PATIENTS/METHODS

A campaign to raise public awareness of DVT was conducted during one year in an urban population of approximately 100,000 (pop A). A comparison urban population of approximately 1,574,000 (pop B) was not exposed to this campaign. Patients symptomatic for DVT in both populations were referred by general practitioners for a standardized compression ultrasound (CUS) of the whole leg at no charge. Positive CUS examinations documented by photographs were analyzed by an independent adjudication committee blinded to the population. Pop A was followed for 8 months after the information campaign ended.

RESULTS AND CONCLUSIONS

  Symptomatic objectively confirmed DVT was found in 48 of 800 subjects tested in pop A and 226 of 2384 tested in pop B. The 1-year incidence of confirmed DVT (proximal and distal) was 46/100,000 (95% CI, 33-59) in A and 14/100,000 (95% CI, 12-16) in B (P < 0.001). The increase in pop A was due to distal DVT (36/100,000 vs. 5/100,000 in pop B, P < 0.001). The DVT rate for pop A in an 8-month follow-up period was 12/100,000, significantly lower than in the first 8 months of the study period (34/100,000/8 months) (P = 0.001). The public awareness campaign significantly increased the diagnosis of distal DVT. When the campaign ended, DVT rates returned to community baseline.

Perioperative risk factors for deep vein thrombosis after total hip arthroplasty or total knee arthroplasty

STUDY OBJECTIVE

To determine the perioperative frequency of deep vein thrombosis (DVT) after lower limb joint prosthesis surgery using Doppler ultrasonography (US).

DESIGN

Prospective cohort study.

SETTING

Operating room and hospital ward.

PATIENTS

144 consecutive ASA physical status 1 and 2 patients who underwent elective total hip arthroplasty (THA; n=64) or total knee arthroplasty (TKA; n= 80).

INTERVENTIONS

Patients were allocated to two groups, those who developed DVT (DVT group) postoperatively and those who did not (no-DVT group). To examine the perioperative risk factors for DVT after THA or TKA, comparative analysis of the two groups was done.

MEASUREMENTS

Doppler US was performed on all patients from the bilateral femoral to lower limb to detect the existence of DVT postoperatively.

MAIN RESULTS

DVT was detected in 61 patients (42%), including three proximal DVT patients (2%). Preoperative elevated plasma D-dimer value [P = 0.0131, odds ratio (OR) 1.54, 95% CI 1.10-2.17] and history of hyperlipidemia (P = 0.0453, OR 6.92, 95% CI 1.04-46.00] were significant risk factors for the onset of DVT. A preoperative plasma D-dimer cutoff value as a diagnostic test was obtained as 0.85 μg/mL.

CONCLUSIONS

A high preoperative plasma D-dimer value and/or history of hyperlipidemia were risk factors for DVT after THA or TKA.

Diagnostic approach to deep venous thrombosis and pulmonary embolism in the critical care setting

Considerable progress has been made during the last 30 years in the prevention, diagnosis, and therapy of venous thromboembolism. This article discusses the epidemiology, pathophysiology, and clinical presentation of the disease as well as the diagnostic uncertainty that exists in the critical care setting. Diagnostic approaches for deep venous thrombosis and pulmonary embolism are considered, including clinical prediction rules, D-dimer, contrast venography, duplex ultrasonography, computed tomographic angiography and venography, magnetic resonance imaging, ventilation–perfusion scanning, chest radiograph, arterial blood gases, electrocardiography, and echocardiography.

Deep Venous Thrombosis of the Lower Limb: No Difference in Duration of Symptoms Between Proximal and Distal Disease

In deep vein thrombosis (DVT) of the lower limb, the location of the thrombosis determines how great the risk of pulmonary embolism is. We set out to determine whether the duration of lower limb DVT symptoms could be a predictive factor for the location of the thrombosis. We retrospectively collected a series of 100 lower limb phlebography examinations that were positive for DVT and divided the group into 2 subgroups proximal disease (ie, above the knee) or distal disease (ie, below the knee). The subgroups were then plotted against the individual duration of the symptoms. Of the 100 DVTs, 58% were proximal, while 42% were distal. The average duration of the symptoms was 6.3 days for patients with proximal disease and 6.2 days for patients with distal disease. We, therefore, found no difference in symptom duration between patients with proximal and distal lower limb DVT. This may imply that the duration of the DVT symptoms does not represent a predictive factor for DVT-caused pulmonary embolism.

Venous thromboembolism following microsurgical breast reconstruction: an objective analysis in 225 consecutive patients using low-molecular-weight heparin prophylaxis

BACKGROUND

Free flap breast reconstruction involves major risk factors for postsurgical venous thromboembolism. The main study objectives were (1) to estimate objectively the incidence of symptomatic and asymptomatic lower extremity deep vein thrombosis in patients who received postoperative thromboprophylaxis after free flap breast reconstruction, (2) to evaluate the safety of low-molecular-weight heparin postoperatively, and (3) to assess the incidence of symptomatic pulmonary embolism or sudden death.

METHODS

A cohort study of 225 consecutive patients who underwent abdominally based free flap breast reconstruction at a single cancer center was conducted. The postoperative thromboprophylaxis regimen was based on the American College of Chest Physicians guidelines. A study group of 118 patients systematically underwent bilateral lower extremity duplex ultrasound before hospital discharge to assess objectively the status of the lower extremity deep venous system. A retrospective cohort of 107 women who were not systematically screened for deep vein thrombosis was used for comparison.

RESULTS

The incidence of postoperative deep vein thrombosis confirmed by duplex ultrasound was 3.4 percent in the study group, all events being clinically silent. Bleeding complications in the entire patient sample were estimated at 5.3 percent. Partial flap loss and total flap loss rates were 2.7 and 1.9 percent, respectively. No venous thromboembolism event was diagnosed in the control group.

CONCLUSIONS

This report shows that the objective incidence of deep vein thrombosis was 3.4 percent within 5 postoperative days in this patient population. The authors' findings support the use of triple thromboprophylaxis and demonstrate that low-molecular-weight heparin is a safe and effective method for prevention of venous thromboembolism in this population.

[Thromboprophylaxis: medical recommendations and hospital programs]

Venous thromboembolism (VTE) is the most preventable cause of death in hospitalized patients. Hospital-related VTE is associated with more than half of the VTE burden in a community, either in-hospital or after discharge. Selective thromboprophylaxis is recommended for patients at risk. Patient selection for thromboprophylaxis requires proper VTE risk stratification. VTE stratification may be achieved by either risk assessment models (RAM) or by models based on patient's illness and associated risk factors. Whatever the model, a thromboprophylatic recommendation should be formulated for each VTE risk category. VTE thromboprophylaxis may include general measures, mechanic compression procedures, pharmacological intervention or a combined approach. After many decades of consensus statements, a large proportion of at risk patients (20% to 75%) still does not receive proper thromboprophylaxis. This study aims to alert to the relevance of thromboprophylaxis and to suggest hospital thromboprophylatic strategies in a Brazilian setting.

Accuracy of ultrasonography performed by critical care physicians for the diagnosis of DVT

BACKGROUND

DVT is common among critically ill patients. A rapid and accurate diagnosis is essential for patient care. We assessed the accuracy and timeliness of intensivist-performed compression ultrasonography studies (IP-CUS) for proximal lower extremity DVT (PLEDVT) by comparing results with the formal vascular study (FVS) performed by ultrasonography technicians and interpreted by radiologists.

METHODS

We conducted a multicenter, retrospective review of IP-CUS examinations performed in an ICU by pulmonary and critical care fellows and attending physicians. Patients suspected of having DVT underwent IP-CUS, using a standard two-dimensional compression ultrasonography protocol for the diagnosis of PLEDVT. The IP-CUS data were collected prospectively as part of a quality-improvement initiative. The IP-CUS interpretation was recorded and timed at the end of the examination on a standardized report form. An FVS was then ordered, and the FVS result was used as the criterion standard for calculating sensitivity and specificity. Time delays between the IP-CUS and FVS were recorded.

RESULTS

A total of 128 IP-CUS were compared with an FVS. Eighty-one percent of the IP-CUS were performed by fellows with <2 years of clinical ultrasonography experience. Prevalence of DVT was 20%. IP-CUS studies yielded a sensitivity of 86% and a specificity of 96% with a diagnostic accuracy of 95%. Median time delay between the ordering of FVS and the FVS result was 13.8 h.

CONCLUSIONS

Rapid and accurate diagnosis of proximal lower extremity DVT can be achieved by intensivists performing compression ultrasonography at the bedside.

D-dimer before chemotherapy might predict venous thromboembolism

To see whether D-Dimer levels can identifying patients at high risk of venous thrombotic events and establish the best benefit/risk-of-bleeding ratio. Current guidelines do not recommend routine prophylaxis against venous thromboembolism (VTE) in cancer patients receiving chemotherapy, but the risk increases about 6.5-fold because of this treatment. D-dimer was measured at baseline in 124 cancer patients scheduled for their first chemotherapy. VTE events, including symptomatic episodes of deep vein thrombosis or pulmonary embolism or both, were recorded during the first 6 months of therapy, and asymptomatic deep vein thrombosis was revealed by compression ultrasonography at baseline and after 90 and 180 days. During follow-up, there were 11 episodes of VTE (8.9%). Mean D-dimer values were higher in patients with VTE (2195 +/- 1382 vs. 695 +/- 1039 ng/ml, (P < 0.001). On grouping D-dimer values in tertiles, only 2.4% (confidence interval, 0.9-5.7%) in the first (<262 ng/ml) and second tertiles (262-650 ng/ml) suffered a deep vein thrombosis/pulmonary embolism event as compared with 22% (confidence interval, 9-34%) in the third (>650 ng/dl) (P = 0.003). The VTE-free interval was significantly shorter in the third tertile than in the first (P = 0.0218, log-rank test; relative risk for third vs. first tertile, 11.0; 95% confidence interval, 1.4-81.3; P = 0.0033). Multivariate analysis found that only baseline D-dimer concentrations were correlated with the subsequent development of VTE. Baseline D-dimer values in cancer patients scheduled for chemotherapy might be used to select those at low risk of VTE, most likely to be safe without prophylaxis.

Negative predictive value of computed tomography pulmonary angiography with indirect computed tomography venography in intensive care unit patients

PURPOSE

The aim of the study was to evaluate the negative predictive value (NPV) of combined computed tomography (CT) pulmonary angiography (CTPA) and indirect CT venography (CTV) in the intensive care unit (ICU) setting.

MATERIALS AND METHODS

We retrospectively reviewed the records of 181 consecutive ICU patients who underwent CTPA/CTV. Radiology reports were examined to determine whether the study was positive for pulmonary embolism (PE), PE and deep venous thrombosis (DVT), or DVT alone; indeterminate; or negative. Results that were reported as negative were further evaluated for evidence of PE or DVT within 30 days by imaging, clinical evaluation, or autopsy data. The outcomes were evaluated for significance by calculating the rate ratio and 95% confidence interval.

RESULTS

A total of 41 patients (22.7%) were diagnosed with venous thromboembolism, 29 (70.7%) with PE, 8 (19.5%) with PE and DVT, and 4 (9.8%) with DVT. Seven studies were considered nondiagnostic. Seventeen deaths occurred within 30 days of CTA/CTV, of which none was felt to be related to PE/DVT. Of the 140 studies read as negative or nondiagnostic, 4 were determined to have venous thromboembolism (3 PEs and 1 DVT) within 30 days of the initial study (NPV = 97.1%). If patients who received prophylactic anticoagulation or inferior vena cava interruption (n = 25) were excluded, NPV decreases to 96.5%

CONCLUSION

A negative CTPA/CTV is reliable for the exclusion of significant venous thromboembolism in ICU patients.