Diagnosis of pulmonary embolism: when is imaging needed?

[Pelvic vein thrombosis : Current treatment options and importance of recanalization procedures]

Venous thrombosis is a frequent disorder. A distinction is made between an acute phase of the disease and a chronic manifestation, the postthrombotic syndrome. In particular, proximal venous thrombosis/pelvic vein thrombosis can cause a life-threatening pulmonary embolism during the acute phase of the disease. The postthrombotic syndrome is characterized by the remodeling of the affected venous section, which is often caused by inflammation. Locally, the typical clinical finding is caused by scarred stricture of the vein with restricted drainage and peripheral venous hypertension. Acute thrombosis should be primarily treated by therapeutic anticoagulation and compression therapy of the affected extremity. The duration of these measures depends on clinical presentation, cause (provoked, unprovoked) and risk factors for venous thrombosis/recurrent thrombosis. Venous revascularization procedures are important both in the acute phase of the disease and in the treatment of postthrombotic syndrome. The recanalization treatment is mostly carried out as an endovascular or hybrid intervention and venous bypass procedures are reserved for special situations.

Predicting pulmonary embolus in orthopedic trauma patients using the Wells score

The decision to perform computed tomography pulmonary angiography (CTPA) to rule out pulmonary embolism (PE) in orthopedic trauma patients is challenging. The Wells score is a commonly used clinical probability tool developed to determine the likelihood of PE and assist in determining the need for CTPA examination. This study evaluated the usefulness of the Wells score for predicting PE in patients admitted to the orthopedic trauma service. All patients who were admitted to the orthopedic trauma service at the authors' institution between 2001 and 2011 who underwent CTPA were identified. The Wells score was calculated retrospectively for each patient, and risk categories using the traditional and alternative interpretations of the Wells score were assigned. Pulmonary embolism was diagnosed in 27 (16%) of 169 patients who underwent CTPA. In total, 27 (0.39%) of 6854 patients admitted to the orthopedic trauma service were diagnosed with PE during initial hospitalization. Mean Wells score was 3.31 (95% confidence interval, ±.28) for the entire population, 3.32 for those without PE (95% confidence interval, ±.31), and 3.28 for those with PE (95% confidence interval, ±.72) (P=.91). Average times from admission to CTPA examination for those with and without PE were 6.18 and 5.7 days, respectively (P=.94). No significant correlation existed between the Wells score and CTPA results, indicating that the Wells score is limited in predicting PE risk in orthopedic trauma patients.

Vena caval thromboses

BACKGROUND

Patients with vena caval (VC) thrombosis have been reported with a variety of clinical presentations, which may create a diagnostic challenge for physicians.

OBJECTIVE

The objective of the study was to evaluate the clinical characteristics of patients with VC thrombosis.

PATIENTS AND METHODS

Files and all imaging methods of consecutive patients with superior or inferior VC thrombosis with or without pulmonary embolism (PE) between January 26, 2001, and May 12, 2006, were retrospectively studied in detail.

RESULTS

In our series, VC thromboses within the inferior and superior VC were detected in 28 patients, mostly by combined computed tomographic venography and spiral computed tomographic pulmonary angiography. Nine of these 28 patients (32.1%) had VC thromboses without PE (7 patients with isolated and 2 patients with nonisolated VC thrombosis). Key symptoms and findings in the 9 patients without PE were unexplained dyspnea and tachypnea, respectively.

CONCLUSIONS

Many patients with VC thrombosis do not have peripheral vein thrombosis. Moreover, nearly one third of patients with VC thrombosis have negative pulmonary angiograms but do have dyspnea and tachypnea.

Multislice-CT bei akuter Lungenembolie

Multidetector-row computed tomographic (CT) angiography of pulmonary arteries is the first-line imaging technique in patients suspected of having pulmonary embolism (PE). Patient risk stratification is important because optimal management, monitoring, and therapeutic strategies depend on the patient's prognosis. Acute right-sided heart failure is known to be responsible for circulatory collapse and death in patients with severe PE. Acute right-sided heart failure can be assessed on CT pulmonary angiography by measuring the dimensions of the right-sided heart cavities or systemic veins. The magnitude of PE can be calculated on CT pulmonary angiography by applying dedicated CT scores or angiographic scores adapted. This article reviews and discusses the various CT-based methods for risk stratification of patients with acute PE.

Electrocardiography and Wells scoring in predicting the anatomic severity of pulmonary embolism

Pulmonary embolism (PE) is a major health problem associated with a significant morbidity and mortality. Immediate recognition of submassive and massive cases is extremely important in order to commencement of early and appropriate therapy that could be life saving. The aim of this study was to assess the ability of two scoring systems, electrocardiography (ECG) and simplified Wells (sWells) clinical scorings in predicting anatomic severity of PE. Hence, ECG and sWells scorings were combined in order to test the hypothesis if this new scoring does enhance the prediction of severity. Fifty six patients with proven PE with high (50 patients) and moderate (six patients)-probability of ventilation/perfusion (V/Q) scan were retrospectively studied. Baseline ECGs were analysed by two independent observers in order to constitute ECG scorings. Baseline sWells scores were also calculated. Anatomic severity of PE was calculated by scintigraphically and categorized into mild (<50% perfusion defect) (group 1), and severe (50% perfusion defect) (group 2) diseases. The mean of ECG scores, sWells scores and the combined scores were 5.23+/-3.42 and 5.85+/-3.82; 6.60+/-1.88 and 7.03+/-2.40; and 10.73+/-3.60 and 11.60+/-4.32 in groups 1 and 2, respectively (p>0.05). An ECG score of 6.5 predicted severe disease (perfusion defect 50%) with a sensitivity of 41.7% and a specificity of 82%). sWells and combined scores did not provide better sensitivity or specificity values based on ROC curve analysis. Our results indicated that ECG scoring could be valuable test in predicting anatomic severity of PE, adding sWells scoring to ECG scoring did not provide any beneficial effect.

Identifying Chest Pain Emergencies in the Primary Care Setting

The majority of patients presenting to a primary care physician with acute chest pain will have non-life-threatening etiologies. Nevertheless, catastrophic cause of chest pain such as ACS, AD, PE, esophageal perforation, and pericarditis must be considered in the differential diagnosis. Often, these deadly conditions have atypical clinical presentations that must be recognized. Furthermore, the physical examination can be deceptively benign in patients harboring a catastrophic etiology of chest pain. By identifying these atypical presentations, recognizing the utility of the physical examination, and understanding of the limitations of traditional diagnostic imaging, primary care physicians can effectively diagnose patients who have life-threatening cause of acute chest pain.

(99m)Tc-NC100668, a new tracer for imaging venous thromboemboli: pre-clinical biodistribution and incorporation into plasma clots in vivo and in vitro

PURPOSE

(99m)Tc-NC100668 is a new radiotracer being developed to aid the diagnosis of thromboembolism. The structure of NC100668 is similar to a region of human alpha(2)-antiplasmin, which is a substrate for factor XIIIa (FXIIIa). The purpose of this study was to confirm the uptake of (99m)Tc-NC100668 into forming plasma clot and to establish the biodistribution of (99m)Tc-NC100668 in Wistar rats.

METHODS

The in vitro plasma clot uptake of (99m)Tc-NC100668 and other compounds with known affinities to FXIIIa was measured using a plasma clot assay. The biodistribution and blood clot uptake of radioactivity of (99m)Tc-NC100668 in normal Wistar rats and those bearing experimentally induced deep vein thrombi were investigated.

RESULTS

The in vitro uptake of (99m)Tc-NC100668 was greater than that for [(14)C]dansyl cadaverine, a known substrate of FXIIIa in the plasma clot assay. The biodistribution of (99m)Tc-NC100668 in male and female Wistar rats up to 24 h p.i. showed that radioactivity was rapidly excreted, predominantly into the urine, with very little background tissue retention. In vivo the uptake and retention of (99m)Tc-NC100668 into the blood clot was greater than could be accounted for by non-specific accumulation of the radiotracer within the blood clot.

CONCLUSION

(99m)Tc-NC100668 was retained by plasma clots in vitro and blood clots in vivo. No significant tissue retention which could interfere with the ability to image thrombi in vivo was observed. This evidence suggests that (99m)Tc-NC100668 might be useful in the detection of thromboembolism.

The role of low-molecular-weight heparins as supportive care therapy in cancer-associated thrombosis

Venous thromboembolism (VTE) is a common complication of malignant disease, affecting approximately 1 in 200 cancer patients. Oncology nurses are instrumental in identifying patients with cancer at high risk of venous thromboembolism. Risk factors include: stage of disease, chemotherapy, the patient's degree of immobility, a history of recent surgery, and the presence of a central venous catheter. The treatment of venous thromboembolism in patients with cancer usually involves a sequential combination of unfractionated heparin or low-molecular-weight heparin (LMWH), followed by oral warfarin or LMWH. LMWHs are an alternative to warfarin for secondary prophylaxis and long-term treatment. LMWH is given by subcutaneous injection, does not require hospitalization for administration or routine laboratory monitoring. Recent clinical trial results have shown that LMWH use is associated with improved survival in cancer patients with relatively good prognoses. Patients receiving any anticoagulant therapy should be monitored for signs of pulmonary embolism or bleeding and intravenous sites (if present) should be monitored for oozing. Appropriate patient selection, a carefully constructed treatment plan, extensive patient education, and regular patient contact are integral elements for the nursing care of patients with cancer-associated thrombosis treated in the outpatient setting.

Acute Pulmonary Embolism: Imaging in the Emergency Department

Acute pulmonary embolism (PE) is a life-threatening condition that requires accurate diagnostic imaging. Morbidity and mortality that result from PE can be reduced significantly if appropriate treatment is initiated early; this makes timely diagnosis imperative. Historically, the gold standard for the imaging of PE has been pulmonary angiography. Rapid advances in radiology and nuclear medicine have led to this modality largely being replaced by noninvasive techniques, most frequently multidetector helical CT pulmonary angiography (CTPA). In cases in which CTPA is contraindicated, other modalities for diagnosis of PE include nuclear ventilation perfusion scanning, magnetic resonance pulmonary angiography, duplex Doppler ultrasonography for deep venous thrombosis, and echocardiography. This article reviews the literature on the role of these imaging modalities in the diagnosis of PE.

Therapeutic Options for the Treatment of Cancer-Associated Thrombosis

OBJECTIVE

To provide oncology nurses with an understanding of therapeutic options for cancer-associated thrombosis, strategies to prevent recurrence, and practical issues in patient management.

DATA SOURCES

Primary and tertiary literature and the author's clinical experience.

CONCLUSION

Oncology nurses monitor patients throughout the care continuum for signs and symptoms indicating vascular thromboembolism and need to know the steps to take to expedite an accurate diagnosis and ensure prompt treatment.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses must keep informed about the evolving evidence that leads to practice changes. They should be able to teach patients about therapeutic options and their potential for improving outcomes.

Diagnosing pulmonary embolism: Experience with spiral CT pulmonary angiography in gynecologic oncology

OBJECTIVES

To review our experience with the diagnosis and prognosis of pulmonary embolism (PE) in gynecologic oncology patients.

METHODS

Spiral CT pulmonary angiography (CTPA) studies on gynecologic oncology patients were collected from our radiology database from 6/2001 to 6/2003. Patient charts were retrospectively reviewed. Data were abstracted relative to presenting symptoms, demographics and laboratory and diagnostic evaluations. Patient data were compared using chi-square contingency tables and logistic regression analysis. Survival was studied using the Kaplan-Meier method and the log rank test. The effect of PE on survival was adjusted using a proportional hazards regression model.

RESULTS

One-hundred and eleven CTPA studies were performed over 2 years and 25 patients were diagnosed with PE. Both PE (n = 25) and non-PE (n = 86) groups were similar for age, race, BMI and cancer diagnosis. Tachycardia (P = 0.02, OR = 3.03 [95% CI 1.16-7.94]) and leukocytosis (P = 0.04, OR = 2.93[95% CI 1.05-8.18]) were more frequent among PE patients and confirmed as independently prognostic of PE. All other clinical and laboratory findings were similar between patients with and without PE. Overall survival for patients with and without PE was 63% versus 94%, respectively, at 2 years (P = 0.02).

CONCLUSION

In a gynecologic oncology patient with high clinical suspicion for PE, our clinical pre-test probability was 23.0%. Two-year mortality rates were 6-fold higher for patients diagnosed with PE. The significant overlap in clinical presentations, multiple risk factors and higher mortality rates encourage the aggressive diagnosis and treatment of PE among this population. Further work is needed to reduce the incidence and mortality rate of PE.

Diagnóstico por imagem do tromboembolismo pulmonar agudo

O diagnóstico do tromboembolismo pulmonar agudo é baseado na probabilidade clínica, uso do dímero D (quando disponível) e na avaliação por imagem. Os principais métodos de imagem utilizados no diagnóstico são representados por cintilografia ventilação-perfusão, angiografia pulmonar e tomografia computadorizada (TC). Na última década vários estudos têm demonstrado que a TC espiral apresenta elevada sensibilidade e especificidade no diagnóstico de tromboembolismo pulmonar agudo. Uma melhor avaliação das artérias pulmonares tornou-se possível com a recente introdução dos equipamentos de TC espirais com multidetectores. Vários pesquisadores têm sugerido que a angiografia pulmonar por TC espiral deve substituir a cintilografia na avaliação de pacientes com suspeita clinica de tromboembolismo pulmonar agudo. Os autores discutem os principais métodos de imagem utilizados no diagnóstico de tromboembolismo pulmonar agudo enfatizando o papel da TC espiral.

[Imaging pulmonary embolism]

The diagnostic performance of computed tomography images of pulmonary embolism is directly related to the acquisition parameters. Any physician evaluating these scans must have proper knowledge of the acquisition, injection, reconstruction, and radiation parameters. Cardiac gating and morphological and functional image processing should be understood since they are now routine techniques particularly important for preoperative assessment of chronic thromboembolism. Elementary knowledge of the imaging techniques reduces the risk of diagnostic limitations. Understanding these techniques does not require any particularly advanced knowledge of physics, data processing or technology, but is necessary to chose the appropriate technical facilities and equipment adapted for diagnostic purposes. While specific training is not a prerequisite, interpretation of an angioscan of the pulmonary vessels does require precise knowledge of the pulmonary anatomy in addition to the technical knowledge mentioned above. Proper analysis may reach the 4th and 5th generation vessels. Different analysis methods have been developed which take into account the technical parameters and avoid the need for serial images. Each slice can then be analyzed within an acquisition Volume. Differential diagnosis is also very technique-dependent, minimally operator-dependent but highly machine-dependent. Differential diagnosis becomes less and less a problem with advancing equipment. Sufficient knowledge of the physiological and pathogenic basis is relatively easy to retain.

Radionuclide imaging of acute pulmonary embolism

Pulmonary embolism (PE) is a potentially fatal condition for which treatment is highly effective. The diagnosis of PE can be challenging and often requires diagnostic imaging. For many years, chest radiographs and ventilation-perfusion (V/Q) scintigraphy have been the primary imaging modalities used in the evaluation of patients with suspected acute PE. The combination of clinical assessment, plus results of V/Q scintigraphy and a noninvasive venous study of the lower extremities can provide clinicians with the information needed to direct treatment in the majority of patients with suspected PE. More recently, advances in computerized tomography (CT) angiography have allowed for the direct visualization of PE, and this technique has emerged as an important diagnostic test in the evaluation of patients with suspected PE. Proponents suggest that CT angiography should be used as the first line imaging test in patients with suspected PE. Others suggest that V/Q scanning should remain as the first line diagnostic imaging test and that CT angiography should be used in patient's in whom the diagnosis remains uncertain. The combination of CT angiography and CT venography has the potential to provide a single comprehensive study of patients with suspected venous thromboembolism.