Silent Pulmonary Embolism Research Articles

Completely Thrombosed Venous Aneurysm in Great Saphenous Vein

Dear Editor: Venous aneurysm (VA) is defined as a solitary area of venous dilatation, not associated with an arteriovenous communication or a pseudoaneurysm1, and appears to be often misdiagnosed as a subcutaneous tumor. Here, we describe the case of VA in a patient's right great saphenous vein, which was difficult to diagnose due to complete thrombosis. An 82-year-old Japanese man presented to our hospital with a 20-year history of an asymptomatic mass on his right inner thigh. Physical examination showed a, non-compressible, slightly relocatable, non-tender, subcutaneous mass 5 cm in diameter (Fig. 1A). The patient had a history of acute myocardial infarction five years earlier, and there was no history of catheterization from the site. The patient had been well controlled with an anticoagulant Clopidogrel. Ultrasound examination revealed a heterogeneous, predominantly hypoechoic mass and a color flow duplex scan showed slight blood flow in the peripheral area of the mass. There were no connecting afferent or efferent veins. Also, there was no deep vein thrombosis. Contrast-enhanced computed tomography (CT) demonstrated a cystic structure whose wall was enhanced. We diagnosed the mass as a subcutaneous cystic tumor such as epidermal cyst, because the mass had a cystic wall and no blood flow in the lumen. After withdrawal of Clopidogrel without heparinization for one week, local excision was performed. Fig. 1 (A) A non-compressible, poorly mobile, non-tender, subcutaneous mass 5 cm in diameter located on the inside of his right thigh. The overlying skin appeared normal. (B) An intraoperative finding. A dark bluish fusiform mass was revealed (arrow). (C) Histological ... Surgical exploration presented a dark bluish fusiform mass connected with an afferent and efferent segment of the great saphenous vein (Fig. 1B). Histological examination revealed a round luminal appearance with abluminal concentric muscular layers and organizing thrombus in the lumen (Fig. 1C). The elastica van Gieson stain revealed that elastic fibers were regularly distributed between the bundles of smooth muscle layers and elastic fibers in the intima were developed (Fig. 1D). A thrombosed VA of the great saphenous vein was diagnosed from all these findings. Six months after the surgery, the patient was symptom-free without any evidence of new lesions. VA can be defined as a persistent isolated dilation of two to three times the normal diameter. VA occurs throughout the body, involving thoracic, visceral, neck, and extremity venous systems2. VA develops equally between the sexes or with a slight female predominance, and is seen at any age. Usually, a definable cause is not present, although trauma, infection, inflammation, congenital vein wall weakness and degenerative change have been proposed. VA in the deep venous system seems to have a greater association with severe thromboembolism such as pulmonary embolism than the superficial system including the great saphenous vein2. Our case was a VA in the superficial system, with no probability of silent pulmonary embolism, and no symptom of pulmonary embolism such as acute shortness of breath had been observed. Five cases of complete thrombosed VA have been reported in English literatures (Table 1)1-5. Our case is the first case which occurred in a great saphenous vein. Of these six cases, only one case was diagnosed precisely by accurate venous ultrasound imaging and CT scanning3, however the other five cases were misdiagnosed as a soft tissue tumor and so on, in spite of various imaging studies1,2,4,5. Table 1 Summary of the five patients with a completely thrombosed venous aneurysm

Health Service Research

Acute pulmonary embolism is a common disease, with an annual incidence of 20 cases per 10 000 inhabitants. In the vast majority of patients, the embolism arises from thrombosis of a deep leg vein. Up to 50% of all patients with a deep vein thrombosis (DVT) of the leg have a—frequently clinically silent—pulmonary embolism. The mortality of acute pulmonary embolism is high, at 7% to 11%, and in the majority of cases recurring embolisms are responsible for the fatal event (1). Early anticoagulant treatment of the DVT lessens the risk of embolism and thus greatly improves the prognosis. The clinical symptoms of DVT may be nonspecific in the extreme. For this reason, the treating physicians frequently embark upon a wide range of diagnostic investigations; admission to hospital is common. For many years diagnostic scores have been sought to enable reliable exclusion of DVT by simple methods that would readily be adopted by primary care physicians. The study presented in this issue (2) was carried out in the offices of primary care physicians in the Dusseldorf and Witten areas of North Rhine–Westphalia, Germany. Patients suspected of having DVT were recruited consecutively over a period of 18 months and subjected to a diagnostic algorithm. The authors used the internationally established Wells scoring system to evaluate each patient’s risk of embolism. Patients adjudged to be at low risk (Wells score ≤ 1) underwent additional D-dimer measurement by means of a validated rapid office test carried out by the primary care physician. Those with a positive D-dimer result or Wells score >1 underwent further diagnostic investigation, usually compression ultrasonography. After 6–8 weeks the patients were seen again—or at least interviewed by telephone—to check their progress, particularly with regard to DVT or pulmonary embolism. Of the 310 patients in whom the diagnostic algorithm excluded DVT, three developed a pulmonary embolism in the follow-up period. The algorithm thus displayed sensitivity of close to 97% and a negative predictive value (NPV) of 99%. In other words, of every 100 patients suspected of having DVT, one had a missed DVT that led to a pulmonary embolism. The physician’s subjective assessment was, as expected, less accurate than the algorithm, although the differences turned out to be astoundingly small. Nine cases of DVT were overlooked, yielding sensitivity of just under 86% and an NPV of 95%, corresponding to five missed DVTs leading to pulmonary embolism per 100 cases. It has to be assumed, however, that the clinical evaluation skills of the primary care physicians trained for participation in the study were more acute than usual. Testing of the authors’ algorithm in clinical practice has thus shown it to possess a high degree of diagnostic accuracy. It will allow the physicians of patients with suspected DVT to dispense with a costly and long drawn out battery of investigative procedures. Nevertheless, the study displays limitations. For example, DVT with only mild clinical symptoms could have been overlooked because of the lack of standardized diagnostic procedures during follow-up. It is unlikely, however, that any clinically symptomatic DVTs and lung embolisms with relevance for the long-term prognosis were missed. Unfortunately the authors provide no data on the individual parameters of the algorithm. How high were the sensitivity and the NPV of the Wells score alone? To what extent were they improved by the assessment of a specially trained experienced physician? What additional information was yielded by the—not inexpensive—D-dimer determination? Ultimately, further investigations are needed to identify a cost-effective yet highly accurate procedure for exclusion of DVT. These limitations notwithstanding, this study marks a sea change with regard to clinical studies. While most earlier investigations were carried out in specialized facilities under conditions far removed from reality, thus excluding a large proportion of the patients seen in routine clinical practice, nowadays the value of “real-life” studies under normal daily conditions is recognized. The necessity of testing diagnostic and therapeutic algorithms and procedures under the conditions of daily clinical practice is becoming increasingly apparent. Other countries are far ahead of Germany in this respect: Primary care physicians have joined together in networks for observational studies and also for clinical testing, because experience has shown that high-quality studies can be conducted within the framework of the law. In Germany, not only physicians but also bodies responsible for health service research at state and federal level have long failed to recognize that medical care benefits from good research under the normal conditions of clinical practice and that any office-based physician can take part in this progress. The article discussed here proves that such research yields results relevant to practice. I hope that the authors’ work will encourage primary care physicians to participate in such research projects in future.

Silent pulmonary embolism in patients with proximal deep vein thrombosis in the lower limbs

One in every three patients with deep vein thrombosis (DVT) in the lower limbs may have silent pulmonary embolism (PE), but its clinical relevance has not been thoroughly studied. We used the RIETE Registry data to study patients with proximal DVT and no PE symptoms, but with a systematic search for PE. We compared the outcome of DVT patients with silent PE and those with no PE. Of 2375 patients with DVT, 842 (35%) had silent PE and 1533 had no PE. During the first 15 days of anticoagulation, patients presenting with silent PE had a higher incidence of symptomatic PE events than those with no PE (0.95% vs. 0.13%; P = 0.015), with a similar incidence of major bleeding (0.95% vs. 1.63%; P = 0.09). In patients with silent PE, the incidence of PE events during the first 15 days was equal to the incidence of major bleeding (eight events each), but in those with no PE the incidence of PE events was eight times lower (3 vs. 25 bleeding events). Multivariate analysis confirmed that DVT patients with silent PE had a higher incidence of symptomatic PE events during the first 15 days than those with no PE (odds ratio, 4.80; 95% CI, 1.27-18.1), with no differences in bleeding. DVT patients with silent PE at baseline had an increased incidence of symptomatic PE events during the first 15 days of anticoagulant therapy. This effect disappeared after 3 months of anticoagulation.

Silent Pulmonary Embolism in Patients with Lower Limb Deep Vein Thrombosis

Abstract 2306 Background:One in every three patients with deep vein thrombosis (DVT) may have silent pulmonary embolism (PE), but its clinical relevance has not been thoroughly studied. Methods: We used the RIETE Registry data to compare the clinical characteristics, diagnostic tests, and 3-month outcome in 842 patients with proximal DVT in the lower limbs and silent PE at baseline, 1533 with DVT without PE, and 585 patients with DVT and symptomatic PE. Results: On admission, a minority of DVT patients (with or without silent PE) presented with hypoxemia (9.0% vs. 6.4%, respectively), or typical PE signs on the chest X-ray (25% vs. 22%) or electrocardiogram (23% vs. 17%). Patients with symptomatic PE more frequently presented with hypoxemia (30%) or had PE signs on the chest X-ray (41%) or electrocardiogram (37%). After the initial 15 days of follow up the incidence of PE was higher among patients with DVT and silent PE compared to those with symptomatic PE (0.95% vs. 0.17%).During the first 90 days of anticoagulant therapy, patients with DVT without PE had a lower incidence of recurrent PE than bleeding (1.0% and 2.9%, respectively). Of note, an excessive risk for bleeding was observed during the first 2 weeks of therapy among patients without PE. Incidence of recurrent PE and major bleeding was similar in DVT patients with silent PE (1.8% and 1.9%) and in those with symptomatic PE (2.6% and 2.7%). Conclusions: Most DVT patients with silent PE have no hypoxemia, chest X-ray signs or electrocardiographic evidence suggestive of embolism. Frequency of recurrent PE was higher among patients with silent PE at the initial 15 days of follow up. In contrast to other subgroups, in DVT patients without PE at baseline, the incidence of major bleeding far exceeded that of PE development during follow up. Disclosures:No relevant conflicts of interest to declare.

Individualised strategy of warfarin treatment for deep vein thromboembolism – case reports

Individualised strategy of warfarin treatment for deep vein thromboembolism – case reports

Factors associated with shunt dynamic in patients with cryptogenic stroke and patent foramen ovale: an observational cohort study

BackgroundAs previously reported there is evidence for a reduction in right to left shunt (RLS) in stroke patients with patent foramen ovale (PFO). This occurs predominantly in patients with cryptogenic stroke (CS). We therefore analysed factors associated with a shunt reduction on follow-up in stroke patients suffering of CS.MethodsOn index event PFO and RLS were proven by transesophageal echocardiography and contrast-enhanced transcranial Doppler-sonography (ce-TCD). Silent PE was proved by ventilation perfusion scintigraphy (V/Q) within the stroke work-up on index event; all scans were re-evaluated in a blinded manner by two experts. The RLS was re-assessed on follow-up by ce-TCD. A reduction in shunt volume was defined as a difference of ≥20 microembolic signals (MES) or the lack of evidence of RLS on follow-up. For subsequent analyses patients with CS were considered; parameters such as deep vein thrombosis (DVT) and silent pulmonary embolism (PE) were analysed.ResultsIn 39 PFO patients suffering of a CS the RLS was re-assessed on follow-up. In all patients (n = 39) with CS a V/Q was performed; the median age was 40 years, 24 (61.5%) patients were female. In 27 patients a reduction in RLS was evident. Silent PE was evident in 18/39 patients (46.2%). Factors such as atrial septum aneurysm, DVT or even silent PE were not associated with RLS dynamics. A greater time delay from index event to follow-up assessment was associated with a decrease in shunt volume (median 12 vs. 6 months, p = 0.013).ConclusionsIn patients with CS a reduction in RLS is not associated with the presence of a venous embolic event such as DVT or silent PE. A greater time delay between the initial and the follow-up investigation increases the likelihood for the detection of a reduction in RLS.

Silent Pulmonary Embolism in Patients with Deep Vein Thrombosis: A Systematic Review

Autopsy reports have shown that as clinicians we under-diagnose or fail to suspect pulmonary embolism (PE) in many of our patients. There have been several studies in the literature that indicate that the prevalence of PE in patients with diagnosed deep vein thrombosis (DVT) is quite high. This study combined data from 28 previous studies on silent PEs to estimate the incidence of PEs among patients with diagnosed DVTs. The authors of this study found that>30% of patients with DVTs without pulmonary complaints had positive diagnostic studies for PE.

High Frequency of Silent Pulmonary Embolism in Patients With Cryptogenic Stroke and Patent Foramen Ovale

Deep vein thrombosis and pulmonary embolism (PE) prove venous embolic activity and enforce the suspicion of paradoxical embolism in patients with stroke with patent foramen ovale. Because it has implications in secondary prevention, we investigated the frequency of silent PE in such a cohort of patients. Patients with cryptogenic stroke or transient ischemic attack and patent foramen ovale who underwent a ventilation perfusion scintigraphy were identified from a stroke registry. Blinded from clinical data, ventilation perfusion scintigraphy scans were re-evaluated independently by 2 experts. Patients showing at least a subsegmental defect were considered as having silent PE. Factors potentially associated with PE were analyzed. The evaluation included 151 patients. Median age was 55.2 years and 59.9% were male. In 56 (37%) patients, silent PE was found; a deep vein thrombosis was evident in 11 (7%) patients. Atrial septal aneurysm was identified in 39 patients and hypermobile atrial septum in 37 patients. Atrial septal aneurysm and hypermobile atrial septum were independently associated with PE. In females, intake of oral contraceptives showed certain association with PE (6 of 25 versus 3 of 40; P=0.07). Silent PE frequently occurs in patients with cryptogenic stroke and patent foramen ovale, particularly when atrial septal aneurysm or hypermobile atrial septum are present.

Silent Pulmonary Embolism in Patients with Deep Venous Thrombosis: A Systematic Review

Purpose To determine, by systematic review of the literature, the prevalence of silent pulmonary embolism in patients with deep venous thrombosis. Methods Twenty-eight included published investigations were identified through PubMed. Studies were selected if methods of diagnosis of pulmonary embolism were described; if pulmonary embolism was stated to be asymptomatic; and if raw data were presented. Studies were stratified according to whether silent pulmonary embolism was diagnosed by a high-probability ventilation-perfusion lung scan using criteria from the Prospective Investigation of Pulmonary Embolism Diagnosis, computed tomography pulmonary angiography, or conventional pulmonary angiography (Tier 1), or by lung scans based on non-Prospective Investigation of Pulmonary Embolism Diagnosis criteria (Tier 2). Results Silent pulmonary embolism was diagnosed in 1665 of 5233 patients (32%) with deep venous thrombosis. This is a conservative estimate because many of the investigations used stringent criteria for the diagnosis of pulmonary embolism. The incidence of silent pulmonary embolism was higher with proximal deep venous thrombosis than with distal deep venous thrombosis. Silent pulmonary embolism seemed to increase the risk of recurrent pulmonary embolism: 25 of 488 (5.1%) with silent pulmonary embolism versus 7 of 1093 (0.6%) without silent pulmonary embolism. Conclusion Silent pulmonary embolism sometimes involved central pulmonary arteries. Because approximately one third of patients with deep venous thrombosis have silent pulmonary embolism, routine screening for pulmonary embolism may be advantageous.

Right atrial spontaneous echo contrast indicates a high incidence of perfusion defects in pulmonary scintigraphy in patients with atrial fibrillation

This study investigated the relationship between right atrial SEC (RA-SEC) and silent pulmonary embolism (PE) in patients with nonvalvular atrial fibrillation (NVAF). Spontaneous echo contrast (SEC) within the cardiac chambers is associated with an increased risk of thromboembolism. However, most studies have examined the relationship between left atrial SEC and systemic thromboembolic disease. Transesophageal echocardiography (TEE) was performed in 210 patients with NVAF to assess a risk of thromboembolism. Right atrial SEC was detected in 37 patients, and 35 of these patients with RA-SEC and 29 patients without RA-SEC were enrolled in this study. However, patients with a history of symptomatic PE or deep vein thrombosis were excluded. Spontaneous echo contrast was diagnosed by TEE as the presence of smoke-like echoes that swirled in a circular pattern. PE was diagnosed by pulmonary scintigraphy. Thrombotic and thrombolytic parameters, including serum concentrations of plasmin-alpha-plasmin inhibitor complex (PIC), thrombin-antithrombin complex (TAT), D-dimer, and fibrinogen were measured in all patients. Left ventricular dimension, cardiac function, and hematologic parameters were similar in the two groups. Nevertheless, the incidence of perfusion defects in pulmonary scintigraphy was significantly higher in the group with RA-SEC (40%) than in the group without RA-SEC (7%; chi-square, P=0.006). The increased incidence of perfusion defects in pulmonary scintigraphy in patients with RA-SEC indicates that right atrial SEC may be a predictable factor at a high risk of PE.

Focally Enhanced F-18 Fluorodeoxyglucose (FDG) Uptake in Incidentally Detected Pulmonary Embolism on PET/CT Scanning

Abnormal F-18 fluorodeoxyglucose (FDG) accumulation patterns in the lung in patients with cancer having whole-body F-18 FDG-PET/CT scanning for restaging purposes are usually associated with primary lung tumors or lung metastases. Other diagnoses include postobstructive pneumonia and/or atelectasis, granulomatous lung disease, or occult lung infarction. In the latter, enhanced F-18 FDG accumulation topographically matches otherwise proven areas of pulmonary embolism. We document focally enhanced F-18 FDG uptake in the thrombus in the right pulmonary artery in a patient with silent pulmonary embolism. We hypothesize that enhanced F-18 FDG accumulation is attributed to the inflammatory reaction and scavenger cell activity associated with the pathophysiological cascade in pulmonary embolism.

The risk of recurrent venous thromboembolism in patients with unprovoked symptomatic deep vein thrombosis and asymptomatic pulmonary embolism

Patients with a first episode of symptomatic pulmonary embolism (PE) have a higher risk of recurrent venous thromboembolism (VTE) than patients with a first episode of proximal lower extremity deep vein thrombosis (DVT). Patients with symptomatic DVT and silent PE may have a different risk of VTE recurrence than patients that have symptomatic DVT without PE. Therefore, it was the aim of this prospective cohort study to compare the risk of recurrent symptomatic VTE in patients with proximal lower extremity DVT and silent PE to the risk in patients that only have proximal lower extremity DVT. Ninety-one consecutive outpatients presenting to the emergency department of a university hospital subsequently hospitalised with a first episode of unprovoked symptomatic proximal lower extremity DVT, and without new pulmonary symptoms were included. Standard initial treatment consisted of intravenous unfractionated heparin or subcutaneous low-molecular-weight heparin for 5-7 days, overlapped with oral vitamin-K antagonist therapy, with long-term oral vitamin-K antagonist therapy (goal INR 2.5 [2.0-3.0]). Study endpoints were: symptomatic recurrent DVT, new PE, and recurrent PE, evaluated by standard objective testing. At enrollment, 28 of 91 (31%) patients with DVT had silent PE. In the patients with DVT and silent PE, there were 3 VTE recurrences during 20 person-years of follow-up, while there were no VTE recurrences during 61 person-years of follow- up in the patients with isolated DVT. The Kaplan-Meier estimated VTE recurrence rate at 1 year after the diagnosis of DVT was 11% (95% CI: 2-28%) for patients with symptomatic DVT and silent PE, compared to 0% in patients with isolated symptomatic DVT (p=0.0045). In patients with a first episode of unprovoked symptomatic acute proximal lower extremity DVT, the risk of recurrent VTE was significantly higher in those with silent PE compared to those without PE.

Should Patients with Deep Vein Thrombosis Alone be Treated as Those with Concomitant Asymptomatic Pulmonary Embolism? A Prospective Study

The established initial treatment of patients with deep vein thrombosis (DVT) or pulmonary embolism (PE) consists of the administration of subcutaneous, weight adjusted, low-molecular weight heparin (LMWH). However, the use of the same LMWH dosages for patients with either DVT or PE is not supported by data from comparative studies. 1,000 consecutive patients with acute, proximal DVT were prospectively evaluated. All patients underwent a ventilation-perfusion lung scan on admission, and remained in hospital for at least 7 days. Patients with silent PE received once daily 10,000 to 15,000 IU subcutaneous LMWH dalteparin according to body weight for 7 days, and then vitamin K antagonists. Patients with DVT alone received LMWH in a fixed dose of 10,000 IU once daily for at least 5 days, and then vitamin K antagonists. The rate of both, major bleeding and symptomatic PE episodes during the 7-day study period was evaluated. Thirteen patients (1.3%) developed recurrent PE (1 died) and 16 patients (1.6%) had major bleeding (7 died). Recurrent PE was significantly more common in patients with silent PE (9 of 258 patients, 3.5%) than in those with DVT alone (4 of 742 patients, 0.5%. Odds ratio: 6.5; p <0.001). There were no significant differences in bleeding rate between patients with silent PE and those with DVT alone. However, the use of a fixed 10,000 IU dose in patients with DVT alone led to a significantly lower bleeding rate in patients weighing over 70 kg: 1 of 349 patients (0.3%) as compared to 9 of 393 patients (2.3%) in those weighing less than 70 kg (odds ratio: 0.12; p = 0.018). Fixed-dose 10,000 IU of LMWH dalteparin once daily proved to be both effective and safe in patients with DVT alone. The observed recurrence rate of 0.5% in these patients compares favourably with the 3.5% rate in patients with silent PE. Furthermore, this fixed-dosage was also safe. Patients weighing over 70 kg had a significant decrease in the rate of major bleeding, and no compensatory increase in the rate of recurrent PE.

Prospective Study on the Usefulness of Lung Scan in Patients with Deep Vein Thrombosis of the Lower Limbs

Asymptomatic pulmonary embolism (PE) is a common finding in patients with deep venous thrombosis (DVT) of the lower limbs, but the usefulness of seeking for silent PE in patients with acute DVT has not been evaluated. This was a prospective study involving consecutive patients with acute symptomatic proximal DVT (confirmed by objective methods) and no clinical suspicion of PE. All patients underwent chest X-ray, ventilation-perfusion lung scan and arterial blood gases on admission, and received anticoagulant therapy. Those with scintigraphic evidence of PE underwent repeated lung scan and blood gases 7 days later. The aim of the study was to assess how many patients with silent PE develop symptoms while on heparin therapy, and in how many of them such symptoms are due to recurrent PE. 946 consecutive patients with acute, proximal DVT had no contraindications to full-dose anticoagulant therapy. Baseline lung scan revealed high-probability defects (silent PE) in 200 (21%). Seven of these 200 patients had symptomatic recurrences during the 7-day study period, and an inferior vena cava filter was inserted. Besides, 6 patients developed PE symptoms, but no new perfusion defects were found on repeated scan. They switched to coumarin therapy, and they did not develop any further complications. Lung scan in patients with symptomatic DVT and no clinical suspicion of PE may be useful, since some patients with silent PE may develop symptoms while on heparin therapy. Without a baseline scintigraphy all these patients would have been considered to have recurrent PE, and vena cava interruption could have been performed.

Silent Pulmonary Embolism of a Large Right Atrial Thrombus

We report the case of a patient who was admitted to the hospital with acute pulmonary embolism 2 weeks after a complicated pelvis fracture. Echocardiography revealed a large, long, and mobile thrombus in the right atrium. The patient was scheduled to undergo urgent surgical thrombectomy. Preoperative echocardiography did not detect any thrombi in the right heart and pulmonary artery. The obvious embolism of this large thrombus in the pulmonary circulation was silent as the patient remained asymptomatic and hemodynamically stable. We discuss the contribution of echocardiography to the appropriate therapeutic management of right atrial thrombi and particularly to the cancellation of urgent operative thrombectomy.

Systemically circulating oxidative species in human deep venous thrombosis

To investigate the hypothesis that plasmatic changes of lipoperoxidative markers are associated with deep venous thrombosis (DVT), peripheral venous blood samples were obtained from 10 patients with venographically proven DVT before starting anticoagulant therapy, and 36+/-3 and 60+/-3 hours later. Values of myeloperoxidase (MPO), 4-hydroxynonenal (HNE) and malondialdehyde (MDA) were compared with those of 10 age-matched control subjects. Despite individual variations, mean plasma MPO level was higher in the DVT group (p < 0.01), as were average plasma MDA (p < 0.001) and HNE (p < 0.01) levels. Separate analysis of the DVT cases showed that higher values of MDA, HNE and MPO were found in patients with either co-morbid diseases or clinically silent pulmonary embolism (PE). Good evidence exists for considering DVT a condition associated with an apparently excessive free radical production not buffered by efficient defence systems. A role of DVT itself cannot be excluded, but PE or other co-morbid diseases may participate in the oxidative stress. If confirmed in a larger series of patients, these findings could shed new light on the plasmatic changes associated with the propagation and complications of DVT, which in turn could have therapeutic implications.

The Characteristics of the Thrombi of the Lower Limbs, as Detected by Ultrasonic Scanning, Do Not Predict Pulmonary Embolism

To evaluate whether pulmonary embolism (PE), as detected by perfusion lung scan, could be predicted by the ultrasonic (US) characteristics of the thrombi in patients with deep venous thrombosis (DVT) of the lower limbs. Ninety-three consecutive patients with DVT and no symptoms of lung involvement (52 men, 41 women; mean age, 67 +/- 17 years). The degree of thrombotic involvement of the lower limbs was assessed using a US score system ranging from 1 (indicating a subsegmental, nonocclusive thrombus) to 16 (massive, occlusive). According to the echographic and color-Doppler features, the thrombi were classified in terms of echoreflectivity, adhesiveness to the vein wall, and organization. The diagnosis of PE (PIOPED criteria) was highly probable in 46% of the patients, intermediate in 15%, low in 8%, and very low/normal in 31%. No correlations were found between the lung scan findings on one side and the venous scoring system or the US features of the thrombi on the other side. While confirming that the prevalence of PE in patients with DVT is elevated, we failed to define a subgroup of patients at higher risk. Our data imply that lung scan should be used extensively for the detection of silent PE and that anticoagulation should not be graded on US findings.

Thromboembolic complications in patients with pelvic trauma.

Patients with pelvic trauma are known to be at increased risk for the development of thromboembolic complications. The incidence of deep venous thrombosis in patients with pelvic fractures is 35% to 60%. Proximal deep venous thrombosis, which is most likely to result in pulmonary embolism, occurs in 25% to 35% of these patients, and almost 1/2 of all proximal thrombi will be in the pelvic veins. The incidence of symptomatic pulmonary embolism in the pelvic trauma population is 2% to 10% whereas a greater proportion of patients will have clinically silent pulmonary embolism. Fatal pulmonary embolism occurs in 0.5% to 2% of patients with pelvic trauma. The cornerstone of effective management is prophylaxis and the most commonly used forms include low dose heparin, low molecular weight heparin, mechanical devices, and in some studies, inferior vena caval filters. Based on a critical review of the literature, in algorithm is proposed for the management of thromboprophylaxis in this trauma subgroup. This includes prophylaxis, screening, and treatment when proximal thrombosis is identified. Such a systematic approach to this potentially catastrophic problem may decrease the morbidity and mortality associated with thromboembolic complications in these patients.

Significance of Silent Pulmonary Embolism in the Spectrum of Thromboembolic Disease

Significance of Silent Pulmonary Embolism in the Spectrum of Thromboembolic Disease

Platelet Count and Venous Thromboembolism: A Useful Test for Suspected Pulmonary Embolism

We have previously reported that patients with deep vein thrombosis (DVT) and scintigraphic evidence of pulmonary embolism (PE) had a fall in platelet count, as compared with their levels before thrombosis had developed. Otherwise, no changes were found in DVT patients without embolism. We recently conducted a prospective study with a larger series of patients and studied platelet count behavior in 189 consecutive patients with acute venous thromboembolism (VTE) in whom a baseline blood cell count was available (obtained before thromboembolism developed). We found no significant differences in baseline platelet counts between groups. However, at the time of VTE diagnosis the analysis of variance demonstrated that mean platelet count was significantly higher in patients without embolism as compared with PE patients (p less than 0.001). On the other hand, no differences were found between patients with silent PE and those with clinically obvious PE. When patients with postoperative VTE and those with nonpostoperative VTE were analyzed separately, mean platelet count increased only in postoperative DVT patients without embolism (p less than 0.001). In the absence of a previous intervention, DVT did not produce any change in platelet count, while PE significantly reduced platelet number (p less than 0.008). In DVT patients without respiratory symptoms of embolism, we suggest that a lung scan should be performed when platelet count is lower than baseline value. For patients with a higher count, the probability of finding PE is very low, and scintigraphy is not cost-effective.