Anticoagulant treatment for subsegmental pulmonary embolism

Special Considerations in Pulmonary Embolism: Clot-in-Transit and Incidental Pulmonary Embolism

This article describes 2 relatively rare, but complex situations in pulmonary embolism (PE): clot-in-transit (CIT), incidental PE (IPE). CIT describes a venous thromboembolism that has become lodged in the right heart. CIT is associated with high mortality and presents unique challenges in management. Incidental PE (IPE) describes PE diagnosed on imaging performed for another indication. The treatment is complex because there is often a disconnect between the PE severity on imaging and lack of severity of the clinical presentation. We summarize the available literature and aid clinicians as they manage patients with PE across the clinical severity spectrum.

Pulmonary embolism following complex trauma: UK MTC observational study

OBJECTIVES

To describe the incidence of pulmonary embolism (PE) in a critically ill UK major trauma centre (MTC) patient cohort.

METHODS

A retrospective, multidataset descriptive study of all trauma patients requiring admission to level 2 or 3 care in the East of England MTC from 1 November 2014 to 1 May 2017. Data describing demographics, the nature and extent of injuries, process of care, timing of PE prophylaxis, tranexamic acid (TXA) administration and CT scanner type were extracted from the Trauma Audit and Research Network database and hospital electronic records. PE presentation was categorised as immediate (diagnosed on initial trauma scan), early (within 72 hours of admission but not present initially) and late (diagnosed after 72 hours).

RESULTS

Of the 2746 trauma patients, 1039 were identified as being admitted to level 2 or 3 care. Forty-eight patients (4.6%) were diagnosed with PE during admission with 14 immediate PEs (1.3%). Of 32.1% patients given TXA, 6.3% developed PE compared with 3.8% without TXA (p=0.08).

CONCLUSION

This is the largest study of the incidence of PE in UK MTC patients and describes the greatest number of immediate PEs in a civilian complex trauma population to date. Immediate PEs are a rare phenomenon whose clinical importance remains unclear. Tranexamic acid was not significantly associated with an increase in PE in this population following its introduction into the UK trauma care system.

Anticoagulant treatment for subsegmental pulmonary embolism

BACKGROUND

Acute pulmonary embolism (PE) is a common cause of death, accounting for 50,000 to 200,000 deaths annually. It is the third most common cause of mortality among the cardiovascular diseases, after coronary artery disease and stroke. The advent of multi-detector computed tomographic pulmonary angiography (CTPA) has allowed better assessment of PE regarding visualisation of the peripheral pulmonary arteries, increasing its rate of diagnosis. More cases of peripheral PEs, such as isolated subsegmental PE (SSPE) and incidental PE, have thereby been identified. These two conditions are usually found in patients with few or none of the classic PE symptoms such as haemoptysis or pleuritic pain, acute dyspnoea or circulatory collapse. However, in patients with reduced cardiopulmonary reserve, classic PE symptoms can be found with isolated SSPEs. Incidental SSPE is found casually in asymptomatic patients, usually by diagnostic imaging performed for other reasons (for example routine CT for cancer staging in oncology patients). Traditionally, all PEs are anticoagulated in a similar manner independent of their location, or number and size of the thrombi. It has been suggested that many patients with SSPE may be treated without benefit, increasing adverse events by a possible unnecessary use of anticoagulants. Patients with isolated SSPE, or incidental PE, may have a more benign clinical presentation compared to those with proximal PEs. However, the clinical significance in patients, and their prognosis, needs to be studied to evaluate whether anticoagulation therapy is required. This is the second update of the Cochrane systematic review published in 2014.

OBJECTIVES

To assess the effectiveness and safety of anticoagulation therapy versus control in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 26 November 2019. We also undertook reference checking to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials of anticoagulation therapy versus control in patients with SSPE or incidental SSPE.

DATA COLLECTION AND ANALYSIS

Two review authors inspected all citations identified to ensure reliable assessment. If relevant studies were identified, we planned for two review authors to independently extract data and to assess the methodological quality of identified trials using the criteria recommended in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We did not identify any studies that met the inclusion criteria.

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials to assess the effectiveness and safety of anticoagulation therapy versus control in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE. Well-conducted research is required before informed practice decisions can be made.

Overdiagnosis of pulmonary embolism: definition, causes and implications

Overuse of computed tomography pulmonary angiography to diagnose pulmonary embolism in people who have only a low pre-test probability of pulmonary embolism has received significant attention in the past. The issue of overdiagnosis of pulmonary embolism, a potential consequence of overtesting, has been less explored. The term “overdiagnosis”, used in a narrow sense, describes a correct (true positive) diagnosis in a person but without any associated harm. The aim of this review is to summarise literature on the topic of overdiagnosis of pulmonary embolism and translate this epidemiological concept into the clinical practice of respiratory professionals. The review concludes that the location of pulmonary embolism at a subsegmental level, rather than whether a diagnosis was made incidentally or following an investigation for suspected pulmonary embolism, is the best predictor for situations in which anticoagulation may not be necessary. In the absence of strong evidence of the optimal management of subsegmental pulmonary embolism, treatment decisions should be made case by case, taking into account the patient's situation and preference.

A suggested definition of overdiagnosis of pulmonary embolism: a diagnosis of pulmonary embolism that, if left untreated, would not lead to more harm than if it were treated with anticoagulation therapy, independent of symptomshttp://ow.ly/wgAK30nr5IV

Magnetic resonance angiography for the primary diagnosis of pulmonary embolism: A review from the international workshop for pulmonary functional imaging

Pulmonary contrast enhanced magnetic resonance angiography (CE-MRA) is useful for the primary diagnosis of pulmonary embolism (PE). Many sites have chosen not to use CE-MRA as a first line of diagnostic tool for PE because of the speed and higher efficacy of computerized tomographic angiography (CTA). In this review, we discuss the strengths and weaknesses of CE-MRA and the appropriate imaging scenarios for the primary diagnosis of PE derived from our unique multi-institutional experience in this area. The optimal patient for this test has a low to intermediate suspicion for PE based on clinical decision rules. Patients in extremis are not candidates for this test. Younger women (< 35 years of age) and patients with iodinated contrast allergies are best served by using this modality We discuss the history of the use of this test, recent technical innovations, artifacts, direct and indirect findings for PE, ancillary findings, and the effectiveness (patient outcomes) of CE-MRA for the exclusion of PE. Current outcomes data shows that CE-MRA and NM V/Q scans are effective alternative tests to CTA for the primary diagnosis of PE.

Nonfatal pulmonary embolism associated with the use of compression stockings in the lithotomy position after spinal anesthesia

A 73-year-old male (height, 156 cm; body weight, 51 kg), without a history of cardiovascular disease or thromboembolic events, was scheduled for transurethral resection of the prostate under spinal anesthesia. Spinal anesthesia was administered with hyperbaric bupivacaine, resulting in an upper anesthetic level of T6. Before surgery, compression stockings were applied to both lower limbs, and the patient was placed in the lithotomy position. Approximately 15 min later, he complained of intolerable chest tightness, followed by tachycardia (heart rate, 110 beats/min) and desaturation (oxygen saturation [SaO₂], 90%). Tracheal intubation was performed immediately. The decrease in end-tidal partial pressure of carbon dioxide (EtCO₂) with an increase in the arterial carbon dioxide partial pressure-EtCO₂ gradient (16 mmHg) suggested pulmonary embolism (PE), which may have been induced by leg manipulation. The patient developed transient hypotension after tracheal intubation; however, his hemodynamic profile stabilized after inotropes administration. Subsequent tests showed normal cardiac enzyme levels; however, his D-dimer levels increased significantly. Imaging confirmed deep vein thrombosis (DVT) and PE. Anticoagulation with warfarin was administered, and he was discharged on the postoperative day 11 without complications. In conclusion, DVT is often a cause of PE. Preoperative identification of DVT risk factors and respiratory symptoms as well as intraoperative monitoring of arterial SaO₂ are vital for timely diagnosis of PE, especially in patients receiving intraoperative lower limb manipulation.

D-dimer test for excluding the diagnosis of pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) can occur when a thrombus (blood clot) travels through the veins and lodges in the arteries of the lungs, producing an obstruction. People who are thought to be at risk include those with cancer, people who have had a recent surgical procedure or have experienced long periods of immobilisation and women who are pregnant. The clinical presentation can vary, but unexplained respiratory symptoms such as difficulty breathing, chest pain and an increased respiratory rate are common.D-dimers are fragments of protein released into the circulation when a blood clot breaks down as a result of normal body processes or with use of prescribed fibrinolytic medication. The D-dimer test is a laboratory assay currently used to rule out the presence of high D-dimer plasma levels and, by association, venous thromboembolism (VTE). D-dimer tests are rapid, simple and inexpensive and can prevent the high costs associated with expensive diagnostic tests.

OBJECTIVES

To investigate the ability of the D-dimer test to rule out a diagnosis of acute PE in patients treated in hospital outpatient and accident and emergency (A&E) settings who have had a pre-test probability (PTP) of PE determined according to a clinical prediction rule (CPR), by estimating the accuracy of the test according to estimates of sensitivity and specificity. The review focuses on those patients who are not already established on anticoagulation at the time of study recruitment.

SEARCH METHODS

We searched 13 databases from conception until December 2013. We cross-checked the reference lists of relevant studies.

SELECTION CRITERIA

Two review authors independently applied exclusion criteria to full papers and resolved disagreements by discussion.We included cross-sectional studies of D-dimer in which ventilation/perfusion (V/Q) scintigraphy, computerised tomography pulmonary angiography (CTPA), selective pulmonary angiography and magnetic resonance pulmonary angiography (MRPA) were used as the reference standard.•

PARTICIPANTS

Adults who were managed in hospital outpatient and A&E settings and were suspected of acute PE were eligible for inclusion in the review if they had received a pre-test probability score based on a CPR.•

INDEX TESTS

quantitative, semi quantitative and qualitative D-dimer tests.• Target condition: acute symptomatic PE.• Reference standards: We included studies that used pulmonary angiography, V/Q scintigraphy, CTPA and MRPA as reference standard tests.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed quality using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). We resolved disagreements by discussion. Review authors extracted patient-level data when available to populate 2 × 2 contingency tables (true-positives (TPs), true-negatives (TNs), false-positives (FPs) and false-negatives (FNs)).

MAIN RESULTS

We included four studies in the review (n = 1585 patients). None of the studies were at high risk of bias in any of the QUADAS-2 domains, but some uncertainty surrounded the validity of studies in some domains for which the risk of bias was uncertain. D-dimer assays demonstrated high sensitivity in all four studies, but with high levels of false-positive results, especially among those over the age of 65 years. Estimates of sensitivity ranged from 80% to 100%, and estimates of specificity from 23% to 63%.

AUTHORS' CONCLUSIONS

A negative D-dimer test is valuable in ruling out PE in patients who present to the A&E setting with a low PTP. Evidence from one study suggests that this test may have less utility in older populations, but no empirical evidence was available to support an increase in the diagnostic threshold of interpretation of D-dimer results for those over the age of 65 years.

Diagnostic Value of Dual-Source Computerized Tomography Combined with Perfusion Imaging for Peripheral Pulmonary Embolism

BACKGROUND

Pulmonary embolism has become the third most common cardiovascular disease, which can seriously harm human health.

OBJECTIVES

To investigate the diagnostic value of dual-source computerized tomography (CT) and perfusion imaging for peripheral pulmonary embolism.

PATIENTS AND METHODS

Thirty-two patients with suspected pulmonary embolism underwent dual-source CT exams. To compare the ability of pulmonary embolism detection software (PED) with CT pulmonary angiography (CTPA) in determining the presence, numbers, and locations of pulmonary emboli, the subsequent images were reviewed by two radiologists using both imaging modalities. Also, the diagnostic consistency between PED and CTPA images and dual-energy pulmonary perfusion imaging (DEPI) for segmental pulmonary embolism was compared.

RESULTS

CTPA images revealed 50 (7.81%) segmental and 56 (4.38%) sub-segmental pulmonary embolisms, while the PED images showed 68 (10.63%) segmental and 94 (7.34%) sub-segmental pulmonary embolisms. Thus, the detection rate on PED images for peripheral pulmonary embolism was significantly higher than that of the CTPA images (P < 0.05). There was good consistency for diagnosing segmental pulmonary embolism between PED and CTPA and DEPI (kappa = 0.85). The sensitivity and specificity of DEPI images for the diagnosis of pulmonary embolism were 91.7% and 97.5%, respectively.

CONCLUSION

PED software of dual-source CT combined with perfusion imaging can significantly improve the detection rate of peripheral pulmonary embolism.

Anticoagulant treatment for subsegmental pulmonary embolism

BACKGROUND

Acute pulmonary embolism (PE) is a common cause of death, accounting for 50,000 to 200,000 deaths annually. It is the third most common cause of mortality among the cardiovascular diseases, after coronary artery disease and stroke.The advent of multi-detector computed tomographic pulmonary angiography (CTPA) has allowed better assessment of PE regarding visualisation of the peripheral pulmonary arteries, increasing its rate of diagnosis. More cases of peripheral PEs, such as isolated subsegmental PE (SSPE) and incidental PE, have thereby been identified. These two conditions are usually found in patients with few or none of the classic PE symptoms such as haemoptysis or pleuritic pain, acute dyspnoea or circulatory collapse. However, in patients with reduced cardio-pulmonary (C/P) reserve the classic PE symptoms can be found with isolated SSPEs. Incidental SSPE is found casually in asymptomatic patients, usually by diagnostic imaging performed for other reasons (for example routine CT for cancer staging in oncologic patients).Traditionally, all PEs are anticoagulated in a similar manner independent of the location, number and size of the thrombi. It has been suggested that many patients with SSPE may be treated without benefit, increasing adverse events by possible unnecessary use of anticoagulants.Patients with isolated SSPE or incidental PE may have a more benign clinical presentation compared with those with proximal PEs. However, the clinical significance in patients and their prognosis have to be studied to evaluate whether anticoagulation therapy is required.This review is an update of a Cochrane systematic review first published in 2014.

OBJECTIVES

To assess the effectiveness and safety of anticoagulation therapy versus no intervention in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE.

SEARCH METHODS

The Cochrane Vascular Trials Search Co-ordinator searched the Specialised Register (last searched December 2015) and CENTRAL (2015, Issue 11). MEDLINE, EMBASE, LILACS and clinical trials databases were also searched.

SELECTION CRITERIA

Randomised controlled trials of anticoagulation therapy versus no intervention in patients with SSPE or incidental SSPE.

DATA COLLECTION AND ANALYSIS

Two review authors inspected all citations to ensure reliable selection. We planned for two review authors to independently extract data and to assess the methodological quality of identified trials using the criteria recommended in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

No studies were identified that met the inclusion criteria.

AUTHORS' CONCLUSIONS

There is no randomised controlled trial evidence for the effectiveness and safety of anticoagulation therapy versus no intervention in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE, and therefore we can not draw any conclusions. Well-conducted research is required before informed practice decisions can be made.

Contrast enhanced pulmonary magnetic resonance angiography for pulmonary embolism: Building a successful program

The performance of contrast enhanced pulmonary magnetic resonance angiography (MRA) for the diagnosis of pulmonary embolism (PE) is an effective non-ionizing alternative to contrast enhanced computed tomography and nuclear medicine ventilation/perfusion scanning. However, the technical success of these exams is very dependent on careful attention to the details of the MRA acquisition protocol and requires reader familiarity with MRI and its artifacts. Most practicing radiologists are very comfortable with the performance and interpretation of computed tomographic angiography (CTA) performed to detect pulmonary embolism but not all are as comfortable with the use of MRA in this setting. The purpose of this review is to provide the general radiologist with the tools necessary to build a successful pulmonary embolism MRA program. This review will cover in detail image acquisition, image interpretation, and some key elements of outreach that help to frame the role of MRA to consulting clinicians and hospital administrators. It is our aim that this resource will help build successful clinical pulmonary embolism MRA programs that are well received by patients and physicians, reduce the burden of medical imaging radiation, and maintain good patient outcomes.

Subsegmental pulmonary embolism: A narrative review

Through the introduction of computed tomography pulmonary angiography (CTPA) for diagnosis of the pulmonary embolism (PE), the high sensitivity of this diagnostic tool led to detecting peripheral filling defects as small as 2-3mm, termed as subsegmental pulmonary embolism (SSPE). However, despite these substantial increases in diagnosis of small pulmonary embolism, there are minimal changes in mortality. Moreover, SSPE patients generally are hemodynamically stable with mild clinical presentation, lower serum level of biomarkers, lower incidence of associated proximal DVTs and less frequent echocardiographic changes compared to the patients with emboli located in more central pulmonary arteries. However, the pros and cons of anticoagulant therapy versus non-treating, monitoring protocol and exact long term outcome of these patients are still unclear. In this article we review existing evidence and provide an overview of what is known about the diagnosis and management of subsegmental pulmonary embolism.