Intermediate Probability Of Pulmonary Embolism Research Articles

Pulmonary Embolism: An Update Based on the Revised AWMF-S2k Guideline.

Pulmonary embolism (PE) is the third most common acute cardiovascular disease. The risk of PE increases with age and mortality is high. Patients are stratified into hemodynamically stable versus unstable patients, as this has important implications for diagnosis and therapy. Since clinical signs and symptoms of acute PE are nonspecific, the clinical likelihood of PE is estimated to guide diagnostic pathways. D-dimer testing is performed in hemodynamically stable patients with low or intermediate probability of PE and the visualization of thromboembolism and its sequelae is commonly achieved with computed tomography pulmonary angiography (CTPA), supplemented by ultrasound techniques. With confirmed PE, another risk stratification estimates disease severity and defines intensity and setting of the ensuing treatment. The therapeutic spectrum ranges from outpatient treatment with initial oral anticoagulation to thrombolytic or interventional treatment in the intensive care unit or catheterization laboratory. In single cases, even acute surgical thrombectomy is attempted.

E-CIGARETTE OR VAPING PRODUCT USE ASSOCIATED LUNG INJURY: A DIAGNOSTIC DILEMMA

E-CIGARETTE OR VAPING PRODUCT USE ASSOCIATED LUNG INJURY: A DIAGNOSTIC DILEMMA

Mismatched perfusion defects on routine ventilation-perfusion scans after lung transplantation.

Incidental pulmonary embolism (PE) is a challenging entity with unclear treatment implications. Our program performs routine ventilation-perfusion (VQ) scans at 3-months post-transplant to establish airway and vascular function. We sought to determine the prevalence and prognostic implications of mismatched perfusion defects (MMPD) found on these studies, hypothesizing they would be associated with a benign prognosis. We studied VQ scans obtained routinely at 3-months post-transplant from double lung transplant recipients 2005-2016 for studies with MMPD interpreted as high or intermediate probability for PE. We tested the relationship between MMPD and 1-year survival via chi square testing, overall survival via Kaplan Meier analysis with log rank testing and peak forced expiratory volume in 1 second (FEV1) percent predicted via t-testing. Three hundred and seventy-three patients met inclusion criteria, of whom 35 (9%) had VQ scans with MMPDs interpreted by radiologists as high or intermediate probability for PE. Baseline recipient and donor characteristics were similar between groups. Seven patients (20%) in the MMPD group were treated with therapeutic anticoagulation. Patients with MMPD had similar 1-year survival (100%vs. 98%, P=1.00), overall survival (log rank P=.90) and peak FEV1% predicted (94% [SD 20%] vs. 92% [SD 21%]; P=.58). Anticoagulation did not affect these relationships. Mismatched perfusion defects on routine post-transplant VQ scan were not associated with a difference in survival or lung function. A conservative approach to these changes may be a viable option in the absence of other anticoagulation indications.

TO ASSESS SAFETY OF WITHHOLDING ANTITHROMBOTIC THERAPY IN PATIENTS WITH LOW OR INTERMEDIATE PROBABILITY OF PULMONARY EMBOLISM

Background & Method: The study was carried out in the Department of Radio diagnosis, Index Medical College, Hospital & Research Centre, Indore, M.P. including 100 chronic bedridden patients with an aim to assess safety of withholding antithrombotic therapy in patients with low or intermediate probability of pulmonary embolism.
 Result: Males represented about 62% of the entire sample. Majority of male patients were in age group 50 and above. Majority (29%) of female patients were of age group of 20 to 40 yrs. On the basis of B-mode sonography and colour Doppler 20% patients were diagnosed to have acute deep vein thrombosis and 12 % patients were diagnosed to have chronic deep vein thrombosis. Out of 100 chronic bedridden patients in the study, 40% were suspected to have deep vein thrombosis on the basis of clinical signs,45% had a positive d-dimer test, 28% were positive on impedence plethysmography. 30% patients were diagnosed to have deep vein thrombosis by B mode sonography and 32% were diagnosed to have deep vein thrombosis by colour Doppler.
 Conclusion: Only 32 patients were positive for deep vein thrombosis out of 100 patients so it is safe to withhold unnecessary anticoagulation therapy in all chronic bed ridden patients because even after 3 month follow up only 1% patients were positive. Impedence plethysmography is less sensitive than ultrasonography and D-dimer test is more sensitive but it lacks specificity so ultrasound and colour Doppler is more sensitive in clinically suspected DVT patients. Ultrasonography and colour Doppler is better predictor of DVT because it is more sensitive and specific, non-invasive, painless, widely available, easy to use, less expensive, no ionizing radiation.
 Keywords: antithrombotic, pulmonary &embolism.

New d-dimer threshold for Japanese patients with suspected pulmonary embolism: a retrospective cohort study

BackgroundIn the diagnosis of pulmonary embolism (PE), the d-dimer threshold is based on studies conducted in Western countries, where the incidence rate is 5 times higher than that in Asian countries, including Japan. If we could elevate the d-dimer threshold based on the low pre-test probability in the Japanese population, we could omit the computed tomography pulmonary angiography (CTPA) which might lead to radiation exposure and contrast-induced nephropathy. Therefore, we aimed to determine a new d-dimer threshold specific to Japanese individuals.MethodsWe conducted a retrospective cohort study at an emergency department in Japan, using medical charts collected from January 2013 to July 2017. We included patients whose d-dimer were measured for suspicion of PE with low or intermediate probability of PE and CTPA were performed. The primary outcome was failure rate of the new d-dimer threshold, defined as the rate of PE detected by CTPA among patients with d-dimer under the new threshold ranging from 1000 to 1500 μg/L by 100. The new d-dimer threshold was appropriate if the upper limit of 95% confidence interval of the failure rate of PE was approximately 3%.ResultsIn 395 patients included, the number of patients with PE was 24 (the prevalence was 6.1%). If the d-dimer threshold was 1100 μg/L, the failure rate was 0% (0/119), the upper limit of the 95% confidence interval of the failure rate was 3.1%, and 30% (119/395) of the CTPA might be omitted.ConclusionThe new d-dimer threshold could safely exclude PE. This result can be generalized to other Asian populations with a lower incidence of PE. Further prospective studies will be needed.

Non-high risk PE in the patients with acute or exacerbated respiratory disease: the value of the algorithm based on D-dimer evaluation and Revised Geneva Score.

The diagnostic algorithm of non-high risk pulmonary embolism (PE) is based on probability scoring systems and plasma D-dimer (DD) assessment. The aim of the present study was to investigate the efficacy of Revised Geneva Scoring (RGS) and DD testing for the excluding of non-high risk PE, in the patients admitted to the hospital due to acute respiratory diseases. The consecutive patients, above 18 years of age, referred to the department of lung diseases, entered the study. The exclusion criteria were: the pregnancy and the suspicion of high risk PE. Plasma DD was measured with quick ELISA test, VIDAS D-dimer New, bioMerieux, France. Multislice computed tomography angiography was performed in all of the patients. 153 patients, median age 65 (19-88) years entered the study. The probability of PE was: low - in 58 patients (38%), intermediate - in 90 (59%), high - in 5 (3%). DD < 500 ng/ml was found in 12% of patients with low and intermediate probability of PE. PE was recognized in 10 out of 153 patients (7%). None of the patients with DD < 500 ng/ml was diagnosed with PE (NPV 100%). Median DD value was significantly higher in PE patients comparing to non-PE (4500 ng/ml and 1356 ng/ml respectively, p = 0.006). In the group of the patients with acute respiratory symptoms, low or intermediate clinical probability scoring combined with normal DD had a high NPV in excluding PE. Nevertheless, such approach was not very effective, as the increased DD was noted in 88% of the examined population.

Acute Pulmonary Embolism: Sensitivity and Specificity of Ventilation-Perfusion Scintigraphy in PIOPED II Study

To use Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II data to retrospectively determine sensitivity and specificity of ventilation-perfusion (V/Q) scintigraphic studies categorized as pulmonary embolism (PE) present or PE absent and the proportion of patients for whom these categories applied. The PIOPED II study had institutional review board approval at all participating centers. Patient informed consent was obtained; the study was HIPAA compliant. Approval and consent included those for future retrospective research. Patients in the PIOPED II database of clinical and imaging results were included if they had diagnosis at computed tomographic (CT) angiography, Wells score, and diagnosis at V/Q scanning. V/Q scan central readings were recategorized as PE present (PIOPED II reading = high probability of PE), PE absent (PIOPED II reading = very low probability of PE or normal), or nondiagnostic (PIOPED II reading = low or intermediate probability of PE). A composite reference standard was used: the PIOPED II digital subtraction angiographic (DSA) result, or if there was no definitive DSA result, CT angiographic results that were concordant with the Wells score (ie, positive CT angiographic result and Wells score > 2 or negative CT angiographic result and Wells score < 6). Sensitivity and specificity of recategorized central readings were computed. With the exclusion of patients with intermediate or low probability, the sensitivity of a high probability (PE present) scan finding was 77.4% (95% confidence interval [CI]: 69.7%, 85.0%), while the specificity of very low probability or normal (PE absent) scan finding was 97.7% (95% CI: 96.4%, 98.9%). The percentage of patients with a PE present or PE absent scan finding was 73.5% (95% CI: 70.7%, 76.4%). In a population similar to that in PIOPED II, results of V/Q scintigraphy can be diagnostically definitive in a majority of patients; thus, it can be considered an appropriate pulmonary imaging procedure in patients for whom CT angiography may be disadvantageous.

Introduction of helical computed tomography affects patient selection for V/Q lung scan

Retrospective analysis for determination of the effect of helical computed tomography (HCT) on utilization of V/Q lung scanning to diagnose pulmonary embolism (PE) in a large general hospital. A total number of 2676 V/Q scans of in- and out-patients referred to our department between March 1992 and December 1998 and between April 1997 and December 1998 were analyzed by an identical group of nuclear physicians. Neither the total number of annually performed V/Q scans (446 +/- 135) nor the mean age of patients (56 years +/- 17) changed significantly since the introduction of HCT. However, the referral pattern was different. The percentage of patients with high and intermediate probability for PE decreased significantly from 15.2% to 9.4% (p < 0.01) and from 10.2% to 7.3% (p < 0.05), respectively. Low probability scans significantly increased from 37.8% to 42.7% (p < 0.05). The percentage of normal scans did not change significantly, however, there was a highly significant increase summarizing patients with normal and low probability scans (74.6% to 83.3%; p < 0.01). The introduction of HCT affected the selection of patients referred for V/Q lung scanning since V/Q scanning was primarily used to exclude rather to confirm PE.

Work-up of patients with malignancy after an intermediate-probability ventilation-perfusion scan: why don't physicians pursue a definitive diagnosis?

The authors determined whether there are specific patient characteristics associated with the clinical decision to eschew further diagnostic testing in patients in whom a ventilation-perfusion (V-P) scan indicates intermediate probability of pulmonary embolism (PE). The authors reviewed all intermediate-probability V-P scans obtained in a 12-month period. Patients were divided into two groups. Group 1 comprised patients in whom a definitive diagnosis of PE was not obtained and who were not treated for PE (n = 57); group 2 comprised patients in whom the diagnosis of PE was confirmed or excluded and who, if PE was confirmed, received appropriate treatment (n = 14). Age, gender, frequency of malignancy, and survival of patients in groups 1 and 2 were compared. The frequency of malignancy was significantly greater in group 1 than in group 2 (P = .012). Although the estimated 2-year survival of group 1 patients was significantly less than that of group 2 patients (P = .039), this difference is likely due to confounding by age and malignancy. When an intermediate-probability V-P scan is obtained, physicians are significantly less likely to pursue a definitive diagnosis of PE in patients with malignancy.

Ultrasound at scintigraphic “intermediate probability of pulmonary embolism” : Christiansen F, Kellerth T, Andersson T, et al. (Diagnostic Radiology, Örebro Medical Center Hospital, S-701 85 Örebro, Sweden). Acta Radiologica 1996;37:14–17

Ultrasound at scintigraphic “intermediate probability of pulmonary embolism” : Christiansen F, Kellerth T, Andersson T, et al. (Diagnostic Radiology, Örebro Medical Center Hospital, S-701 85 Örebro, Sweden). Acta Radiologica 1996;37:14–17

Rater agreement in lung scintigraphy.

The PIOPED criteria in their original and revised forms are today's standards in the interpretation of ventilation-perfusion scintigraphy. When the PIOPED criteria are used by experienced raters with training in consensus interpretation, the agreement rates have been demonstrated to be excellent. Our purpose was to investigate the rates of agreement between 2 experienced raters from different hospital who had no training in consensus interpretation. The 2 raters investigated a population of 195 patients. This group included 72 patients from a previous study who had an intermediate probability of pulmonary embolism and who had also been examined by pulmonary angiography. The results demonstrated moderate agreement rates with a kappa value of 0.54 (0.45-0.63 in a 95% confidence interval), which is similar to the kappa value of the PIOPED study but significantly lower than the kappa values of agreement rates among consensus-trained raters. There was a low consistency in the intermediate probability category, with a proportional agreement rate of 0.39 between the experienced raters. The moderate agreement rates between raters from different hospitals make it difficult to compare study populations of a certain scintigraphic category in different hospitals. Further investigations are mandatory for accurate diagnosis when the scintigrams are in the category of intermediate probability of pulmonary embolism.

Ultrasound at Scintigraphic “Intermediate Probability of Pulmonary Embolism”

For diagnosis of pulmonary embolism (PE), ventilation/perfusion lung scintigraphy is routinely used; approximately one-third of the patients will have the diagnosis "intermediate probability of PE" (inconclusive). In this group only about 33% are found to have pulmonary emboli if examined with pulmonary angiography. To evaluate the diagnostic, therapeutic, and economic consequences of ultrasound of the legs as a complementary diagnostic investigation to "intermediate probability", 72 consecutive patients were investigated with bilateral ultrasound of the proximal deep veins of the legs and pulmonary angiography in a prospective study. Ten patients had PE, of whom 7 had deep venous thrombosis, and 62 had no PE, of whom 2 had deep venous thrombosis. The negative predictive value of ultrasound was 0.95. In view of the importance of adequate treatment and rational use of public health care expenditure, complementary diagnostics should be performed, and ultrasound is an adequate complementary investigation.

Ultrasound at Scintigraphic “Intermediate Probability of Pulmonary Embolism”

Ultrasound at Scintigraphic “Intermediate Probability of Pulmonary Embolism”

Ultrasound at Scintigraphic “Intermediate Probability of Pulmonary Embolism”

Ultrasound at Scintigraphic “Intermediate Probability of Pulmonary Embolism”

Scintigraphic Appearances in Patients With Pulmonary Infection and Lung Scintigrams of Intermediate or Low Probability for Pulmonary Embolism

Out of 294 patients with lung scintigrams of low or intermediate probability for pulmonary embolism, the appearances in 54 patients with a final diagnosis of pulmonary infection were reviewed. The most common finding was a matched defect in ventilation and perfusion occurring in 40 patients (76%). Regional reverse mismatch occurred in 13 patients (24%) and both appearances were found in one patient (2%). Reverse mismatch was also present in a further seven patients, four of whom had bronchial obstruction. Although occurring less frequently than matched defects, 81% of regional reverse mismatched defects were because of chest infection. The presence of regional reverse mismatch in patients investigated for pulmonary embolism suggests the alternative diagnosis of chest infection.

Pulmonary embolism: confirmation with venous duplex US as adjunct to lung scanning.

To assess the prevalence of deep venous thrombosis with venous duplex ultrasonography (US) in patients who underwent radionuclide lung scanning for evaluation of clinically suspected pulmonary embolism (PE) and to assess the clinical usefulness of this type of US in the selection of patients for anticoagulant therapy. Two hundred eighty-five lung scan and duplex US examinations in 267 consecutive patients seen between January 1987 and June 1990 with clinical evidence of PE (151 men and 134 women, aged 17-98 years [mean, 57 years]) were retrospectively reviewed. Lung scans were divided into four groups: normal, depicting up to 30% probability of PE, indeterminate or intermediate probability of PE, and greater than 90% probability of PE. Thrombotic disease was confirmed with US in seven (21%) of 33 patients with normal lung scans and in 64 (25%) of 252 patients with abnormal lung scans. Venous duplex Doppler US is a useful adjunct to lung scanning in patients with signs and/or symptoms of PE.

An Evaluation of Preoperative and Postoperative Ventilation and Perfusion Lung Scintigraphy in the Screening for Pulmonary Embolism After Elective Orthopedic Surgery

One hundred two patients undergoing elective knee or hip arthroplasty were studied with radionuclide ventilation scans (V) and perfusion scans (Q) preoperatively (preop) and postoperatively (postop) to assess their relative value in the diagnosis of asymptomatic pulmonary embolism (PE) after orthopedic surgery. Postop Q were read in combination with preop V and Q and postop V using prospective investigation of pulmonary embolism diagnosis (PIOPED) criteria. Of 25 postop Q interpreted as either high or intermediate probability for PE, preop Q were judged useful in 96%; the postop V were useful in 78%; and the preop V were not helpful in any of the cases. Of 63 postop Q interpreted as low probability, preop Q were useful in 74%; the postop V were useful in only 33%; and the preop V were useful in only one case. When postop Q were read as normal (14 cases), none of the three auxiliary studies were found to be useful. Overall, postop V were more helpful than preop Q in only 2%, and preop V contributed significantly in only 1%. This experience suggests that preop Q alone is the most useful adjunct to the postop Q in the postoperative evaluation for PE. The authors conclude that to screen for asymptomatic PE after elective orthopedic surgery, preop Q should be performed in all cases, preop V are not necessary, and postop V need be performed only if a baseline preop Q is not available.

Pulmonary arterial hypertension: value of perfusion scintigraphy.

Records of 34 patients with established causes of pulmonary arterial hypertension were retrospectively reviewed. The ventilation-perfusion scans were blindly classified according to standardized criteria as normal or high, low, or intermediate probability of pulmonary embolism as the cause of pulmonary arterial hypertension. Twelve of 13 patients with primary pulmonary hypertension had normal or low-probability scans, but the perfusion pattern was not helpful in distinguishing between histologic subtypes. All eight patients with large-vessel thromboembolic hypertension had high-probability scans; however, three of 13 patients with nonembolic secondary pulmonary hypertension also had high-probability scans. While a normal or low-probability scan excluded proximal pulmonary emboli as a cause of pulmonary hypertension, a high-probability scan may be associated with a variety of other nonembolic causes of secondary pulmonary hypertension.

Emergency radionuclide scans

Radionuclide diagnostic imaging is an important adjunct to the diagnosis and treatment of several conditions that present to the emergency department. The emergency physician should be able to properly apply these tests. A normal radionuclide perfusion lung scan can reliably rule out pulmonary embolism. The use of the radionuclide ventilation lung scan may help interpretation of a perfusion lung scan that is of intermediate probability for pulmonary embolism. A radionuclide venogram of the lower extremities is both sensitive and accurate for detecting the presence of deep venous thrombosis. A radionuclide testicular scan is invaluable in the workup of the acute scrotum, as long as the test is available in a timely manner and the diagnosis has not been established by another means. A multiple-gated acquisition cardiac scan can help make the diagnosis of cardiac contusion after other causes of cardiac instability have been corrected. The renal radionuclide scan is useful in the workup of obstructive uropathy, especially if intravenous pyelography is contraindicated. The hepatobiliary nuclear scan is able to help differentiate acute cholecystitis from other causes of right upper quadrant pain. Proper and timely use of these tests can prevent serious sequelae from a missed diagnosis, and in some cases eliminate the need for invasive tests, dangerous treatment, or even exploratory surgery when it is unwarranted.

Ventilation imaging with Kr-81m

Sixty-five patients with suspected pulmonary embolism were studied prospectively with both Kr-81m and Xe-133 ventilation imaging and Tc-99m MAA perfusion imaging. The krypton images, perfusion scintigrams and chest radiographs were read independently of the xenon images, perfusion scintigrams and chest radiographs by three observers. The studies of 53 patients were interpreted as normal or as indicative of a low or intermediate probability for pulmonary embolism with both gases. One study indicated intermediate probability with Xe-133 due to diffuse, severe xenon retention but low probability with Kr-81m because of close ventilation-perfusion correspondence. The studies of 9 patients indicated a high probability of embolism with both gases, while those of two additional patients (one with emboli at angiography) indicated a high probability only with Kr-81m. While essential agreement between Xe-133 and Kr-81m ventilation imaging was found in most patients, the significant difference in interpretation in 2 of 11 patients with probable pulmonary embolism suggests that a controlled, prospective trial with pulmonary angiography is warranted before Kr-81m is employed for routine clinical use.