When a test is too good: how CT pulmonary angiograms find pulmonary emboli that do not need to be found

Diagnosis of Pulmonary Embolism with d-Dimer Adjusted to Clinical Probability

BACKGROUND

Retrospective analyses suggest that pulmonary embolism is ruled out by a d-dimer level of less than 1000 ng per milliliter in patients with a low clinical pretest probability (C-PTP) and by a d-dimer level of less than 500 ng per milliliter in patients with a moderate C-PTP.

METHODS

We performed a prospective study in which pulmonary embolism was considered to be ruled out without further testing in outpatients with a low C-PTP and a d-dimer level of less than 1000 ng per milliliter or with a moderate C-PTP and a d-dimer level of less than 500 ng per milliliter. All other patients underwent chest imaging (usually computed tomographic pulmonary angiography). If pulmonary embolism was not diagnosed, patients did not receive anticoagulant therapy. All patients were followed for 3 months to detect venous thromboembolism.

RESULTS

A total of 2017 patients were enrolled and evaluated, of whom 7.4% had pulmonary embolism on initial diagnostic testing. Of the 1325 patients who had a low C-PTP (1285 patients) or moderate C-PTP (40 patients) and a negative d-dimer test (i.e., <1000 or <500 ng per milliliter, respectively), none had venous thromboembolism during follow-up (95% confidence interval [CI], 0.00 to 0.29%). These included 315 patients who had a low C-PTP and a d-dimer level of 500 to 999 ng per milliliter (95% CI, 0.00 to 1.20%). Of all 1863 patients who did not receive a diagnosis of pulmonary embolism initially and did not receive anticoagulant therapy, 1 patient (0.05%; 95% CI, 0.01 to 0.30) had venous thromboembolism. Our diagnostic strategy resulted in the use of chest imaging in 34.3% of patients, whereas a strategy in which pulmonary embolism is considered to be ruled out with a low C-PTP and a d-dimer level of less than 500 ng per milliliter would result in the use of chest imaging in 51.9% (difference, -17.6 percentage points; 95% CI, -19.2 to -15.9).

CONCLUSIONS

A combination of a low C-PTP and a d-dimer level of less than 1000 ng per milliliter identified a group of patients at low risk for pulmonary embolism during follow-up. (Funded by the Canadian Institutes of Health Research and others; PEGeD ClinicalTrials.gov number, NCT02483442.).

Clinical presentation and outcomes in elderly patients with symptomatic isolated subsegmental pulmonary embolism

OBJECTIVES

Data are limited on clinical presentation and outcomes in elderly patients with acute symptomatic isolated subsegmental pulmonary embolism (SSPE). We compared clinical presentation, risk factors, processes of care, and outcomes between elderly patients with SSPE and patients with more proximal pulmonary embolism (PE).

METHODS

We prospectively followed 578 patients aged ≥65 years with acute symptomatic isolated SSPE or proximal PE in a multicentre Swiss cohort study. We compared quality of life at three months using the PEmb-QoL, and examined the independent association between localization of PE and clinical outcomes (recurrent venous thromboembolism [VTE], overall mortality) using regression models with adjustment for potential confounders.

RESULTS

Overall, 11% of patients had isolated SSPE. Patients with SSPE were less likely to have a pulse ≥110/min (3% vs. 13%), but more likely to have active cancer (28% vs. 15%) and to receive outpatient care (11% vs. 4%) than patients with proximal PE. Virtually all patients (98%) with SSPE received anticoagulants. Quality of life did not differ between the groups at 3 months. No patient with SSPE vs. seven patients with proximal PE died from the index PE event. No significant difference was observed for the 3-year cumulative incidence of recurrent VTE (7% vs. 12%) and death (29% vs. 20%). After adjustment, SSPE was not associated with a lower risk of clinical outcomes than proximal PE.

CONCLUSIONS

Clinical presentation and incidences of adverse outcomes did not differ significantly between elderly patients with SSPE or proximal PE, although the power to detect differences might have been limited given the small number of events. Thus, our study does not provide evidence that unselected, elderly patients with SSPE have a more benign clinical course.

Cascades of Care After Incidental Findings in a US National Survey of Physicians

IMPORTANCE

Incidental findings on screening and diagnostic tests are common and may prompt cascades of testing and treatment that are of uncertain value. No study to date has examined physician perceptions and experiences of these cascades nationally.

OBJECTIVE

To estimate the national frequency and consequences of cascades of care after incidental findings using a national survey of US physicians.

DESIGN, SETTING, AND PARTICIPANTS

Population-based survey study using data from a 44-item cross-sectional, online survey among 991 practicing US internists in a research panel representative of American College of Physicians national membership. The survey was emailed to panel members on January 22, 2019, and analysis was performed from March 11 to May 27, 2019.

MAIN OUTCOMES AND MEASURES

Physician report of prior experiences with cascades, features of their most recently experienced cascade, and perception of potential interventions to limit the negative consequences of cascades.

RESULTS

This study achieved a 44.7% response rate (376 completed surveys) and weighted responses to be nationally representative. The mean (SE) age of respondents was 43.4 (0.7) years, and 60.4% of respondents were male. Almost all respondents (99.4%; percentages were weighted) reported experiencing cascades, including cascades with clinically important and intervenable outcomes (90.9%) and cascades with no such outcome (94.4%). Physicians reported cascades caused their patients psychological harm (68.4%), physical harm (15.6%), and financial burden (57.5%) and personally caused the physicians wasted time and effort (69.1%), frustration (52.5%), and anxiety (45.4%). When asked about their most recent cascade, 33.7% of 371 respondents reported the test revealing the incidental finding may not have been clinically appropriate. During this most recent cascade, physicians reported that guidelines for follow-up testing were not followed (8.1%) or did not exist to their knowledge (53.2%). To lessen the negative consequences of cascades, 62.8% of 376 respondents chose accessible guidelines and 44.6% chose decision aids as potential solutions.

CONCLUSIONS AND RELEVANCE

The survey findings indicate that almost all respondents had experienced cascades after incidental findings that did not lead to clinically meaningful outcomes yet caused harm to patients and themselves. Policy makers and health care leaders should address cascades after incidental findings as part of efforts to improve health care value and reduce physician burnout.

Prevalence and Cost of Care Cascades After Low-Value Preoperative Electrocardiogram for Cataract Surgery in Fee-for-Service Medicare Beneficiaries

IMPORTANCE

Low-value care is prevalent in the United States, yet little is known about the downstream health care use triggered by low-value services. Measurement of such care cascades is essential to understanding the full consequences of low-value care.

OBJECTIVE

To describe cascades (tests, treatments, visits, hospitalizations, and new diagnoses) after a common low-value service, preoperative electrocardiogram (EKG) for patients undergoing cataract surgery.

DESIGN, SETTING, AND PARTICIPANTS

Observational cohort study using fee-for-service Medicare claims data from beneficiaries aged 66 years or older without known heart disease who were continuously enrolled between April 1, 2013, and September 30, 2015, and underwent cataract surgery between July 1, 2014 and June 30, 2015. Data were analyzed from March 12, 2018, to April 9, 2019.

EXPOSURES

Receipt of a preoperative EKG. The comparison group included patients who underwent cataract surgery but did not receive a preoperative EKG.

MAIN OUTCOMES AND MEASURES

Cascade event rates and associated spending in the 90 days after preoperative EKG, or in a matched timeframe for the comparison group. Secondary outcomes were patient, physician, and area-level characteristics associated with experiencing a potential cascade.

RESULTS

Among 110 183 cataract surgery recipients, 12 408 (11.3%) received a preoperative EKG (65.6% of them were female); of those, 1978 (15.9%) had at least 1 potential cascade event. The comparison group included 97 775 participants (63.1% female). Those who received a preoperative EKG experienced between 5.11 (95% CI, 3.96-6.25) and 10.92 (95% CI, 9.76-12.08) additional events per 100 beneficiaries relative to the comparison group. This included between 2.18 (95% CI, 1.34-3.02) and 7.98 (95% CI, 7.12-8.84) tests, 0.33 (95% CI, 0.19-0.46) treatments, 1.40 (95% CI, 1.18-1.62) new patient cardiology visits, and 1.21 (95% CI, 0.62-1.79) new cardiac diagnoses. Spending for the additional services was up to $565 per Medicare beneficiary (95% CI, $342-$775), or an estimated $35 025 923 annually across all Medicare beneficiaries in addition to the $3 275 712 paid for the preoperative EKGs. Among preoperative EKG recipients, those who were older (adjusted odds ratio [aOR] for patients aged 75 to 84 years vs 66 to 74 years old, 1.42; 95% CI, 1.28-1.57), had more chronic conditions (aOR for each additional Elixhauser condition, 1.18; 95% CI, 1.14-1.22), lived in more cardiologist-dense areas (aOR, 1.05; 95% CI, 1.02-1.09), or had their preoperative EKG performed by a cardiac specialist rather than a primary care physician (aOR, 1.26; 95% CI, 1.10-1.43) were more likely to experience a potential cascade.

CONCLUSIONS AND RELEVANCE

Care cascades after preoperative EKG for cataract surgery are infrequent but costly. Policy and practice interventions to reduce low-value services and the cascades that follow could yield substantial savings.

Computed tomography pulmonary angiography using high-pitch dual-source scanner technology

Objectives:

To compare use of ultra-fast high-pitch dual-source free-breathing computed tomography pulmonary angiogram (CTPA) with conventional standard-pitch single-source breath-hold CTPA.

Methods:

This retrospective comparative study was conducted in Radiology Department at King Fahad Military Medical Complex Dhahran, Saudi Arabia from July 2016 to December 2017. Patients (N=130) were divided into 2 groups, each having 65 consecutive patients; Group-1 (single-source CT) and Group-2 (dual-source CT). Previously treated pulmonary embolism cases, pregnant patients and those with incomplete data were excluded. Image quality was subjectively assessed by 2 readers for adequacy of contrast opacification and pulmonary vessel outline, and presence of artifacts (breathing motion, cardiac pulsation, and contrast related). Scan acquisition times and radiation doses were also compared. Chi-square and t-test were used to determine association.

Results:

Improved image quality (optimal studies without artifacts 91%) was seen in Group-2 compared to Group-1 (optimal studies without artifacts 75.4%). Also, reduced scan time (1-2 sec.) and radiation dose (mean dose length product (DLP)-248 mGy-cm) were observed in Group-2 compared to Group-1 (scan time- 6.5 sec, mean DLP-375). Results were found significant (p<0.05).

Conclusion:

High-pitch dual-source CT with free-breathing yields better image quality, reduces image acquisition time and radiation doses.

Pearls and Myths in the Evaluation of Patients with Suspected Acute Pulmonary Embolism

Significant improvement has been achieved in diagnostic accuracy, validation of probability scores, and standardized treatment algorithms for patients with suspected acute pulmonary embolism. These developments have provided the tools for a safe and cost-effective management for most of these patients. In our experience, however, the presence of medical myths and ongoing controversies seem to hinder the implementation of these tools in everyday clinical practice. This review provides a selection of such dilemmas and controversies and discusses the published evidence beyond them. By doing so, we try to overcome these dilemmas and suggest pragmatic approaches guided by the available evidence and current guidelines.

General practitioner use of D-dimer in suspected venous thromboembolism: historical cohort study in one geographical region in the Netherlands

OBJECTIVES

To investigate how many general practitioner (GP)-referred venous thromboembolic events (VTEs) are diagnosed during 1 year in one geographical region and to investigate the (urgent) referral pathway of VTE diagnoses, including the role of laboratory D-dimer testing.

DESIGN

Historical cohort study.

SETTING

GP patients of 47 general practices in a demarcated geographical region of 161 503 inhabitants in the Netherlands.

PARTICIPANTS

We analysed all 895 primary care patients in whom either the GP determined a D-dimer value or who had a diagnostic work-up for suspected VTE in a non-academic hospital during 2015.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcomes of this study were the total number of VTEs per year and the diagnostic pathways-including the role of GP determined D-dimer testing-of patients urgently referred to secondary care for suspected VTE. Additionally, we explored the use of an age-adjusted D-dimer cut-off.

RESULTS

The annual VTE incidence was 0.9 per 1000 inhabitants. GPs annually ordered 5.1 D-dimer tests per 1000 inhabitants. Of 470 urgently GP-referred patients, 31.3% had a VTE. Of those urgently referred based on clinical assessment only (without D-dimer testing), 73.8% (96/130) had a VTE; based on clinical assessment and laboratory D-dimer testing yielded 15.0% (51/340) VTE. Applying age-adjusted D-dimer cut-offs to all patients aged 50 years or older resulted in a reduction of positive D-dimer results from 97.9% to 79.4%, without missing any VTE.

CONCLUSIONS

Although D-dimer testing contributes to the diagnostic work-up of VTE, GPs have a high detection rate for VTE in patients who they urgently refer to secondary care based on clinical assessment only.

Treatment and Long-Term Clinical Outcomes of Incidental Pulmonary Embolism in Patients With Cancer: An International Prospective Cohort Study

PURPOSE

Pulmonary embolism is incidentally diagnosed in up to 5% of patients with cancer on routine imaging scans. The clinical relevance and optimal therapy for incidental pulmonary embolism, particularly distal clots, is unclear. The aim of the current study was to assess current treatment strategies and the long-term clinical outcomes of incidentally detected pulmonary embolism in patients with cancer.

PATIENTS AND METHODS

We conducted an international, prospective, observational cohort study between October 22, 2012, and December 31, 2017. Unselected adults with active cancer and a recent diagnosis of incidental pulmonary embolism were eligible. Outcomes were recurrent venous thromboembolism, major bleeding, and all-cause mortality during 12 months of follow-up. Outcome events were centrally adjudicated.

RESULTS

A total of 695 patients were included. Mean age was 66 years and 58% of patients were male. Most frequent cancer types were colorectal (21%) and lung cancer (15%). Anticoagulant therapy was initiated in 675 patients (97%), of whom 600 (89%) were treated with low-molecular-weight heparin. Recurrent venous thromboembolism occurred in 41 patients (12-month cumulative incidence, 6.0%; 95% CI, 4.4% to 8.1%), major bleeding in 39 patients (12-month cumulative incidence, 5.7%; 95% CI, 4.1% to 7.7%), and 283 patients died (12-month cumulative incidence, 43%; 95% CI, 39% to 46%). The 12-month incidence of recurrent venous thromboembolism was 6.4% in those with subsegmental pulmonary embolism compared with 6.0% in those with more proximal pulmonary embolism (subdistribution hazard ratio, 1.1; 95% CI, 0.37 to 2.9; P = .93).

CONCLUSION

In patients with cancer with incidental pulmonary embolism, risk of recurrent venous thromboembolism is significant despite anticoagulant treatment. Patients with subsegmental pulmonary embolism seemed to have a risk of recurrent venous thromboembolism comparable to that of patients with more proximal clots.

Clinical Probability Tools for Deep Venous Thrombosis, Pulmonary Embolism, and Bleeding

Overdiagnosis of venous thromboembolism is associated with increasing numbers of patient complications and health care burden. Multiple clinical tools exist to estimate the probability of pulmonary embolism and deep venous thrombosis. When used with d-dimer testing, these can further stratify venous thromboembolism risk to help inform the use of additional diagnostic testing. Although there are similar tools to estimate bleeding risk, these are not as well-validated and lack reliability.

Independent and incremental value of ventilation/perfusion PET/CT and CT pulmonary angiography for pulmonary embolism diagnosis: results of the PECAN pilot study

PURPOSE

This pilot study assessed the independent and incremental value of ⁶⁸Ga-V/Q PET/CT as compared with CT pulmonary angiography (CTPA) for the management of cancer patients with suspected acute pulmonary embolism (PE).

METHODS

All 24 cancer patients with suspected acute PE prospectively recruited underwent both ⁶⁸Ga-V/Q PET/CT and CTPA within 24 h. PET/CT was acquired after inhalation of Galligas prepared using a Technegas generator and administration of ⁶⁸Ga-macroaggregated albumin. Initially, PET/CT and CTPA scans were read independently with the reader blinded to the results of the other imaging study. CTPA and PET/CT were then coregistered and reviewed by consensus between a radiologist and nuclear medicine physician. The therapeutic management was established by the managing physician based on all available data.

RESULTS

The diagnostic conclusion was concordantly negative in 18 patients (75%). Of the six discordant diagnoses on independent reading, combined interpretation of V/Q PET/CTPA enabled a consensus conclusion in two patients, excluding PE in one and confirming PE in the other, similar to the initial diagnostic conclusion of the V/Q PET/CT. Of the remaining four patients, three had a single subsegmental thrombus on CTPA but a negative V/Q PET/CT scan, and two of these did not receive long-term anticoagulation and did not have a venous thromboembolic event during a 3-year follow-up period. The third patient, along with a patient with a positive V/Q PET/CT scan but a negative CTPA scan, presented with acute complications preventing any conclusions with regard to the appropriateness of the V/Q PET/CT results in the management of PE. Overall, V/Q PET had an impact on management in four patients (17%).

CONCLUSION

In this pilot study, we demonstrated the feasibility and potential utility of V/Q PET/CT for the management of patients with suspected PE. V/Q PET/CT may be of particular relevance in patients with equivocal findings or isolated subsegmental findings on CTPA, adding further discriminatory information to allow important decision-making regarding the use or withholding of anticoagulation. Given the other advantages of V/Q PET/CT (reduced acquisition time, low radiation dose), and with the increasing availability of ⁶⁸Ga generators, PET/CT is a potential replacement for V/Q SPECT/CT imaging.

Accuracy of registration algorithms in subtraction CT of the lungs: A digital phantom study

Purpose

The purpose of this study was to assess, using an anthropomorphic digital phantom, the accuracy of algorithms in registering precontrast and contrast‐enhanced computed tomography (CT) chest images for generation of iodine maps of the pulmonary parenchyma via temporal subtraction.

Materials and methods

The XCAT phantom, with enhanced airway and pulmonary vessel structures, was used to simulate precontrast and contrast‐enhanced chest images at various inspiration levels and added CT simulation for realistic system noise. Differences in diaphragm position were varied between 0 and 20 mm, with the maximum chosen to exceed the 95th percentile found in a dataset of 100 clinical subtraction CTs. In addition, the influence of whole body movement, degree of iodine enhancement, beam hardening artifacts, presence of nodules and perfusion defects in the pulmonary parenchyma, and variation in noise on the registration were also investigated. Registration was performed using three lung registration algorithms — a commercial (algorithm A) and a prototype (algorithm B) version from Canon Medical Systems and an algorithm from the MEVIS Fraunhofer institute (algorithm C). For each algorithm, we calculated the voxel‐by‐voxel difference between the true deformation and the algorithm‐estimated deformation in the lungs.

Results

The median absolute residual error for all three algorithms was smaller than the voxel size (1.0 × 1.0 × 1.0 mm³) for up to an 8 mm diaphragm difference, which is the average difference in diaphragm levels found clinically, and increased with increasing difference in diaphragm position. At 20 mm diaphragm displacement, the median absolute residual error after registration was 0.85 mm (interquartile range, 0.51–1.47 mm) for algorithm A, 0.82 mm (0.50–1.40 mm) for algorithm B, and 0.91 mm (0.54–1.52 mm) for algorithm C. The largest errors were seen in the paracardiac regions and close to the diaphragm. The impact of all other evaluated conditions on the residual error varied, resulting in an increase in the median residual error lower than 0.1 mm for all algorithms, except in the case of whole body displacements for algorithm B, and with increased noise for algorithm C.

Conclusion

Motion correction software can compensate for respiratory and cardiac motion with a median residual error below 1 mm, which was smaller than the voxel size, with small differences among the tested registration algorithms for different conditions. Perfusion defects above 50 mm will be visible with the commercially available subtraction CT software, even in poorly registered areas, where the median residual error in that area was 7.7 mm.

The problem of under-diagnosis and over-diagnosis of pulmonary embolism

Pulmonary embolism (PE) is an increasingly recognised condition which is associated with significant morbidity and mortality. Despite the better awareness of this serious condition, the diagnosis is still overlooked in many cases with sometimes fatal consequences. Under-diagnosis may be due to several reasons including reliance on non-specific 'classic' symptoms, belief that bedside measurements will likely be abnormal in the setting of acute PE, and confounding factors like co-existent cardiorespiratory diseases or being in an intensive care unit, where the diagnosis may not be considered. At the same time, incidental diagnosis of PE is occurring more often due to frequent use of imaging investigations alongside advancements in CT technology, and dilemma exists as to whether the chance finding of PE requires anticoagulation, especially when identified only at the subsegmental level. This article reviews these two issues of under-diagnosis and over-diagnosis of PE in the current era.

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

Expanding disease and undermining the ethos of medicine

The expansion of the concept of disease poses problems for epidemiology. Certainly, new diseases are discovered and more people are treated earlier and better. However, the historically unprecedented expansion is criticised for going too far. Overdiagnosis, overtreatment, and medicalization are some of the challenges heatedly debated in medicine, media, and in health policy making. How are we to analyse and handle the vast expansion of disease? Where can we draw the line between warranted and unwarranted expansion? To address this issue, which has wide implications for epidemiology, we need to understand how disease is expanded. This article identifies six ways that our conception of disease is expanded: by increased knowledge (epistemic), making more phenomena count as disease (ontological), doing more (pragmatic), defining more (conceptual), and by encompassing the bad (ethic) and the ugly (aesthetic). Expanding the subject matter of medicine extends its realm and power, but also its responsibility. It makes medicine accountable for ever more of human potential dis-eases. At the same time it blurs the borders and undermines the demarcation of medicine. Six specific advices can guide our action clarifying the subject matter of medicine in general and epidemiology in particular. To avoid unlimited responsibility and to keep medicine on par with its end, we need to direct the expansion of disease to what effectively identifies or reduces human suffering. Otherwise we will deplete medicine and undermine the greatest asset in health care: trust.

Diagnosis and treatment of subsegmental pulmonary embolism

Subsegmental pulmonary embolism (SSPE) affects the 4th division and more distal pulmonary arterial branches. SSPE can be isolated or affect multiple subsegments, be symptomatic or incidental (unsuspected) and may or may not be associated with deep vein thrombosis. Symptoms, clinical risk scores and biomarkers are less sensitive for diagnosing SSPE compared to more central pulmonary embolism. The diagnosis is confirmed using radiological imaging, predominately computed tomographic pulmonary angiogram (CTPA) or ventilation/perfusion scanning. The increasing utilization of CTPAs may have resulted in overdiagnosis driven by smaller pulmonary emboli. There is insufficient evidence of improved mortality or reduced venous thromboembolism recurrence with anticoagulation treatment for SSPE however, the major and clinically significant haemorrhage risks are well described. As the resolution of diagnostic imaging has improved, we may be viewing the natural physiological filtering process performed by the lungs that may not require treatment.

Safety of the Combination of PERC and YEARS Rules in Patients With Low Clinical Probability of Pulmonary Embolism: A Retrospective Analysis of Two Large European Cohorts

BACKGROUND

This study aimed to determine the failure rate of a combination of the PERC and the YEARS rules for the diagnosis of pulmonary embolism (PE) in the emergency department (ED).

METHODS

We performed a retrospective analysis of two European cohorts of emergency patients with low gestalt clinical probability of PE (PROPER and PERCEPIC). All patients we included were managed using a conventional strategy (D-dimer test, followed, if positive, by computed tomographic pulmonary angiogram (CTPA). We tested a diagnostic strategy that combined PERC and YEARS to rule out PE. The primary endpoint was a thromboembolic event diagnosed in the ED or at 3-months follow-up. Secondary endpoints included a thromboembolic event at baseline in the ED and a CTPA in the ED. Ninety-five percent confidence intervals (CIs) of proportions were calculated with the use of Wilson's continuity correction.

RESULTS

We analyzed 1,951 patients (mean ± SD age = 47 ± 18 years, 56% women) with an overall proportion of patients with PE of 3.5%. Both PERC and YEARS strategies were associated with 11 missed PE in the ED: failure rate 0.57 (95% CI = 0.32-1.02). At 3-month follow-up, the overall failure rate was 0.83% (95% CI = 0.51-1.35). Among the 503 patients who underwent a CTPA (26%), the use of the PERC-YEARS combination would have ruled out PE without CTPA in 249 patients (50% [95%CI = 45%-54%], absolute reduction 13% (95% CI = 11%-14%]).

CONCLUSION

The combination of PERC then YEARS was associated with a low risk of PE diagnostic failure and would have resulted in a relative reduction of almost half of CTPA.

Prognostic value of Mastora obstruction score in acute pulmonary embolism

BACKGROUND

To evaluate the clinical significance of Mastora obstruction score in hemodynamically stable patients with acute pulmonary embolism (aPE).

MATERIALS AND METHODS

One-hundred-and-six patients with newly diagnosed aPE, confirmed by computed tomography pulmonary angiography (CTPA), were included in the study and prospectively examined. aPE severity was assessed by using Mastora obstruction score. According to the Mastora index, patients were divided into "non-massive" and "massive" groups. The  patients' medical histories and blood laboratory data were collected, and instrumental tests were performed and analyzed.

RESULTS

Eighty-two (77%) of the patients had "non-massive" aPE. Cough (48%), fever (44%), and pleural effusion (48%) occurred significantly more often in the  "non-massive" PE group, while syncope (42%) and right ventricular dysfunction (86%) were more frequent in the  "massive" PE group. The  probability of the  right ventricular dysfunction was significantly higher in the  presence of increased pulmonary artery pressure (Cramer's V = 0.410; p < 0.0001) and respiratory failure (Cramer's V = 0.247; p = 0.032). Increased CRP level was found in the majority of the patients (90%). D-dimer level <500 μg/L (lower than the commonly recommended cut-off level) was found in 5% of cases.

CONCLUSIONS

The clinical manifestation depends on the massiveness of aPE. Division of aPE cases into two groups suggests two possible subtypes of aPE: cardiovascular and respiratory. The "non-massive" aPE was associated with respiratory symptoms and an inflammatory response. The  "massive" aPE is associated with an increased D-dimer level and leads to cardiovascular disorders. However, the "massive" aPE may be presented by normal D-dimer concentration level.

Wells and Geneva Scores Are Not Reliable Predictors of Pulmonary Embolism in Critically Ill Patients: A Retrospective Study

BACKGROUND

Critically ill patients are at high risk for pulmonary embolism (PE). Specific PE prediction rules have not been validated in this population. The present study assessed the Wells and revised Geneva scoring systems as predictors of PE in critically ill patients.

METHODS

Pulmonary computed tomographic angiograms (CTAs) performed for suspected PE in critically ill adult patients were retrospectively identified. Wells and revised Geneva scores were calculated based on information from medical records. The reliability of both scores as predictors of PE was determined using receiver operating characteristic (ROC) curve analysis.

RESULTS

Of 138 patients, 42 (30.4%) were positive for PE based on pulmonary CTA. Mean Wells score was 4.3 (3.5) in patients with PE versus 2.7 (1.9) in patients without PE (P < .001). Revised Geneva score was 5.8 (3.3) versus 5.1 (2.5) in patients with versus without PE (P = .194). According to the Wells and revised Geneva scores, 56 (40.6%) patients and 49 (35.5%) patients, respectively, were considered as low probability for PE. Of those considered as low risk by the Wells score, 15 (26.8%) had filling defects on CTA, including 2 patients with main pulmonary artery embolism. The area under the ROC curve was 0.634 for the Wells score and 0.546 for the revised Geneva score. Wells score >4 had a sensitivity of 40%, specificity of 87%, positive predictive value of 59%, and negative predictive value of 77% to predict risk of PE.

CONCLUSIONS

In this population of critically ill patients, Wells and revised Geneva scores were not reliable predictors of PE.

Fatal recurrent VTE after anticoagulant treatment for unprovoked VTE: a systematic review

Current guidelines recommend long-term anticoagulant therapy in patients with unprovoked venous thromboembolism (VTE). The risk of fatal recurrent VTE after treatment discontinuation (versus that of fatal bleeding during anticoagulation) is of particular relevance in the decision to continue or stop anticoagulation after the first 3 months. Our primary aim was to provide a point-estimate of the yearly rate of fatal recurrent VTE and VTE case-fatality rate in patients with unprovoked VTE after anticoagulation cessation. Data were extracted from both randomised controlled trials and observational studies published before May 1, 2017. The pooled fatality rates were calculated using a random-effects model. 18 studies with low-to-moderate bias were included in the primary analysis, totalling 6758 patients with a median (range) follow-up duration of 2.2 (1–5) years. After anticoagulation cessation, the weighted pooled rate of VTE recurrence was 6.3 (95% CI 5.4–7.3) per 100 patient-years and the weighted pooled rate of fatal recurrent VTE was 0.17 (95% CI 0.047–0.33) per 100 patient-years, for a case-fatality rate of 2.6% (95% CI 0.86–5.0). These numbers are a solid benchmark for comparison to the risks associated with long-term anticoagulation treatment for the decision on the optimal duration of treatment of patients with unprovoked VTE.

Can an age-adjusted D-dimer level be adopted in managing venous thromboembolism in the emergency department? A retrospective cohort study

INTRODUCTION

Patients suspected of having venous thromboembolism (VTE), with a low pretest probability, undergo D-dimer testing. A negative D-dimer, in a low-risk patient rules out VTE with a high degree of certainty because of its high sensitivity. It is, however, a poorly specific test, and the absolute value increases with age. The aim of this study was to establish whether an age-adjusted D-dimer could be safely used instead of a standard cut-off level in low-risk patients over the age of 50 years.

PATIENTS AND METHODS

This was a retrospective review of 1649 patients with suspected VTE whose D-dimer levels were analysed. In low-risk patients (defined as 'VTE unlikely' using the dichotomized Wells' scores), the outcomes in terms of confirmed VTE diagnosis, hospital admission and investigations using an age-adjusted D-dimer level (measured in D-dimer units) of 5× the age for patients over 50 years of age and 250 ng/ml for patients younger than 50 years of age, was compared with the cut-off standard level (230 ng/ml in all patients).

RESULTS

Of the total group of patients in the VTE unlikely group, the proportion of patients with a negative D-dimer when using the standard cut-off was 64.9% (859/1324). A further 130 patients had a negative D-dimer when the age-adjusted cut-off was used, increasing the proportion of all patients in whom VTE could be excluded without imaging to 74.7% (989/1324).For those patients of 75 years or older, the proportion of patients in whom VTE could be excluded without imaging increased from only 91/242 (37.6%) when using the standard D-dimer cut-off to 154/242 (63.6%) when the age-adjusted cut-off was used.These changes occurred without any additional false-negative findings.

CONCLUSION

For patients over the age of 50 years suspected of having VTE with a low pretest probability, increasing the D-dimer cut-off level to 5× the age increases the proportion of patients in whom VTE can safely be excluded without radiological imaging.

Retrospective validation of the pulmonary embolism rule-out criteria rule in 'PE unlikely' patients with suspected pulmonary embolism

INTRODUCTION

Patients presenting to emergency departments (EDs) with suspected pulmonary embolism (PE) can be risk stratified and those who are deemed to be at low risk for PE usually undergo D-dimer testing. A negative D-dimer in this low-risk group rules out PE with a high degree of certainty because of its high sensitivity. The D-dimer is, however, a poorly specific test and positive results often lead to unnecessary radiological imaging (notably computed tomography pulmonary angiography). The Pulmonary Embolism Rule-Out Criteria (PERC) rule has been suggested as an alternative to D-dimer testing in these patients. This study looked at whether the PERC rule could safely replace the use of D-dimer in patients suspected of PE, but deemed 'PE unlikely' by the dichotomized Wells score in a UK ED setting.

PATIENTS AND METHODS

This was a retrospective review of 986 patients with suspected PE who had a blood sample for D-dimer level taken. In patients deemed 'PE unlikely' (using the dichotomized Wells score), the diagnostic performance of the PERC rule was compared with a standard D-dimer level in the detection of PE at index presentation and up to 3 months afterwards.

RESULTS

Of the 986 patients, 940 patients were deemed 'PE unlikely' using the dichotomized Wells score. Three patients with confirmed PE would have been missed by the PERC rule compared with only one missed by the D-dimer test. In these patients, the sensitivity of the PERC rule for detecting PE was 91.4% [95% confidence interval (CI): 76.9-98.2%], with a negative likelihood ratio of 0.25 (95% CI: 0.08-0.73). However, the negative predictive value of the PERC rule was 99.1% (95% CI: 97.3-99.8%). In comparison, the sensitivity for the standard D-dimer test was 97.1% (95% CI: 85.1-99.9%), with a negative likelihood ratio of 0.04 (95% CI: 0.01-0.27). The negative predictive value for the standard D-dimer test was 99.8% (95% CI: 99.2-100%).

CONCLUSION

The PERC rule has a high negative predictive value for excluding PE in patients presenting with suspected PE to the ED. However, the PERC rule may still miss around 8% of confirmed PE in patients who are deemed 'PE unlikely' by a dichotomized Wells score. Caution is advised in using the PERC rule as a substitute for the standard D-dimer test in all these patients.

Paediatric overdiagnosis modelled by coronary abnormality trends in Kawasaki disease

OBJECTIVE

Compare trends in coronary artery (CA) abnormality diagnoses to trends in adverse cardiac outcomes among American children with Kawasaki disease (KD) to assess the fit of detection of CA abnormalities to an established model of overdiagnosis.

DESIGN

Multicenter retrospective cohort.

SETTING

48 US children's hospitals in the Paediatric Health Information System database.

PARTICIPANTS

Children <18 years receiving care for KD between 2000 and 2014.

MAIN OUTCOME MEASURES

The main outcomes were rates of CA abnormality diagnoses and adverse cardiac outcomes, measured during a child's incident KD visit and longitudinally at all subsequent visits to the same hospital, through December 2016. CA abnormalities were considered severe if long-term anticoagulation other than aspirin was prescribed. Trends were tested using mixed effects logistic regression, adjusting for patient demographics.

RESULTS

Among 17 809 children treated for KD, a CA abnormality was diagnosed in 1435 children (8%), including 1117 considered non-severe and 318 severe. The rate of non-severe CA abnormality diagnoses increased from 45 per 1000 patients with KD in 2000 to 81 per 1000 patients with KD in 2014, representing an adjusted 2.3-fold increased odds (95% CI 1.8 to 3.0) of diagnosis. There was no significant change in diagnoses of severe CA abnormalities. Adverse cardiac outcomes were stable over the study period at 19 per 1000 patients with KD (P=0.24 for trend).

CONCLUSIONS

The rising rate of detection of non-severe CA abnormalities accompanied by an unchanging rate of adverse cardiac outcomes among American children with KD fits an overdiagnosis pattern.

Overdiagnosis in primary care: framing the problem and finding solutions

Overdiagnosis, is defined as the diagnosis of a condition that, if unrecognized, would not cause symptoms or harm a patient during his or her lifetime, and it is increasingly acknowledged as a consequence of screening for cancer and other conditions. Because preventive care is a crucial component of primary care, which is delivered to the broad population, overdiagnosis in primary care is an important problem from a public health perspective and has far reaching implications. The scope of overdiagnosis as a result of services delivered in primary care is unclear, though overdiagnosis of indolent breast, prostate, thyroid, and lung cancers is well described and overdiagnosis of chronic kidney disease, depression, and attention-deficit/hyperactivity disorder is also recognized. However, overdiagnosis is a known consequence of all screening and can be assumed to occur in many more clinical contexts. Overdiagnosis can harm patients by leading to overtreatment (with associated potential toxicities), diagnosis related anxiety or depression, and labeling, or through financial burden. Many entrenched factors facilitate overdiagnosis, including the growing use of advanced diagnostic technology, financial incentives, a medical culture that encourages greater use of tests and treatments, limitations in the evidence that obscure the understanding of diagnostic utility, use of non-beneficial screening tests, and the broadening of disease definitions. Efforts to reduce overdiagnosis are hindered by physicians' and patients' lack of awareness of the problem and by confusion about terminology, with overdiagnosis often conflated with related concepts. Clarity of terminology would facilitate physicians' understanding of the problem and the growth in evidence regarding its prevalence and downstream consequences in primary care. It is hoped that international coordination regarding diagnostic standards for disease definitions will also help minimize overdiagnosis in the future.

Commentary to 18F-GP1, a Novel PET Tracer Designed for High-Sensitivity, Low-Background Detection of Thrombi: Imaging Activated Platelets in Clots-Are We Getting There?

Thrombus formation can lead to heart attacks, stroke and pulmonary embolism, which are major causes of mortality. Current standard diagnostic imaging methods detect anatomic abnormalities such as vascular flow impairment but have limitations. By using a targeted molecular imaging approach critical components of a pathology can be selectively visualized and exploited for an improved diagnosis and patient management. The GPIIb/IIIa receptor is abundantly and specifically exposed on activated platelets and is the key receptor in thrombus formation. This commentary describes the current status of GPIIb/IIIa-based PET imaging approaches with a focus on the recently published preclinical data of the small-molecule PET tracer ¹⁸F-GP1. Areas of future research and potential clinical applications are discussed that may lead to an improved detection of critical thromboembolic events and an optimization of available antithrombotic therapies by tracking activated platelets.

Imaging of acute pulmonary embolism: an update

Imaging plays an important role in the evaluation and management of acute pulmonary embolism (PE). Computed tomography (CT) pulmonary angiography (CTPA) is the current standard of care and provides accurate diagnosis with rapid turnaround time. CT also provides information on other potential causes of acute chest pain. With dual-energy CT, lung perfusion abnormalities can also be detected and quantified. Chest radiograph has limited utility, occasionally showing findings of PE or infarction, but is useful in evaluating other potential causes of chest pain. Ventilation-perfusion (VQ) scan demonstrates ventilation-perfusion mismatches in these patients, with several classification schemes, typically ranging from normal to high. Magnetic resonance imaging (MRI) also provides accurate diagnosis, but is available in only specialized centers and requires higher levels of expertise. Catheter pulmonary angiography is no longer used for diagnosis and is used only for interventional management. Echocardiography is used for risk stratification of these patients. In this article, we review the role of imaging in the evaluation of acute PE.

Pulmonary embolism

Pulmonary embolism (PE) is caused by emboli, which have originated from venous thrombi, travelling to and occluding the arteries of the lung. PE is the most dangerous form of venous thromboembolism, and undiagnosed or untreated PE can be fatal. Acute PE is associated with right ventricular dysfunction, which can lead to arrhythmia, haemodynamic collapse and shock. Furthermore, individuals who survive PE can develop post-PE syndrome, which is characterized by chronic thrombotic remains in the pulmonary arteries, persistent right ventricular dysfunction, decreased quality of life and/or chronic functional limitations. Several important improvements have been made in the diagnostic and therapeutic management of acute PE in recent years, such as the introduction of a simplified diagnostic algorithm for suspected PE as well as phase III trials demonstrating the value of direct oral anticoagulants in acute and extended treatment of venous thromboembolism. Future research should aim to address novel treatment options (for example, fibrinolysis enhancers) and improved methods for predicting long-term complications and defining optimal anticoagulant therapy parameters in individual patients, and to gain a greater understanding of post-PE syndrome.

Prevalence of pulmonary embolism in syncope patients

Clinical question

How often is pulmonary embolism (PE) found in patients admitted for syncope?

Article chosen

Prandoni P, Lensing A, Prins M, et al. Prevalence of pulmonary embolism among patients hospitalized for syncope (PESIT). N Engl J Med 2016;375:1524-31, doi: 10.1056/NEJMoa1602172.

Objective

To determine the prevalence of PE in patients hospitalized for a first episode of syncope.

Current and future burden of venous thrombosis: Not simply predictable

Venous thrombosis is a major contributor to the global disease burden. In this review we aim to answer two important questions: (1) are we making progress in reducing this disease burden and (2) how can we further improve? To answer these questions, we first evaluated the disease burden, that is, the incidence of first venous thrombosis over the past decade(s) and discuss its most important determinants. We found that the incidence of first venous thrombosis remained relatively unchanged, despite an increase in risk factor prevalence and a rise in identification of subsegmental pulmonary emboli due to enhanced image quality and utilization. This is, however, balanced by improved thromboprophylaxis strategies, resulting in an overall unchanged venous thrombosis incidence. We can further improve by developing, validating, and implementing risk assessment strategies, allowing us to identify persons at high or low risk in whom thromboprophylaxis can be provided or withheld, respectively.

ACR Appropriateness Criteria® Acute Chest Pain-Suspected Pulmonary Embolism

Pulmonary embolism (PE) remains a common and important clinical condition that cannot be accurately diagnosed on the basis of signs, symptoms, and history alone. The diagnosis of PE has been facilitated by technical advancements and multidetector CT pulmonary angiography, which is the major diagnostic modality currently used. Ventilation and perfusion scans remain largely accurate and useful in certain settings. Lower-extremity ultrasound can substitute by demonstrating deep vein thrombosis; however, if negative, further studies to exclude PE are indicated. In all cases, correlation with the clinical status, particularly with risk factors, improves not only the accuracy of diagnostic imaging but also overall utilization. Other diagnostic tests have limited roles. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Effect of the Pulmonary Embolism Rule-Out Criteria on Subsequent Thromboembolic Events Among Low-Risk Emergency Department Patients: The PROPER Randomized Clinical Trial

IMPORTANCE

The safety of the pulmonary embolism rule-out criteria (PERC), an 8-item block of clinical criteria aimed at ruling out pulmonary embolism (PE), has not been assessed in a randomized clinical trial.

OBJECTIVE

To prospectively validate the safety of a PERC-based strategy to rule out PE.

DESIGN, SETTING, AND PATIENTS

A crossover cluster-randomized clinical noninferiority trial in 14 emergency departments in France. Patients with a low gestalt clinical probability of PE were included from August 2015 to September 2016, and followed up until December 2016.

INTERVENTIONS

Each center was randomized for the sequence of intervention periods. In the PERC period, the diagnosis of PE was excluded with no further testing if all 8 items of the PERC rule were negative.

MAIN OUTCOMES AND MEASURES

The primary end point was the occurrence of a thromboembolic event during the 3-month follow-up period that was not initially diagnosed. The noninferiority margin was set at 1.5%. Secondary end points included the rate of computed tomographic pulmonary angiography (CTPA), median length of stay in the emergency department, and rate of hospital admission.

RESULTS

Among 1916 patients who were cluster-randomized (mean age 44 years, 980 [51%] women), 962 were assigned to the PERC group and 954 were assigned to the control group. A total of 1749 patients completed the trial. A PE was diagnosed at initial presentation in 26 patients in the control group (2.7%) vs 14 (1.5%) in the PERC group (difference, 1.3% [95% CI, -0.1% to 2.7%]; P = .052). One PE (0.1%) was diagnosed during follow-up in the PERC group vs none in the control group (difference, 0.1% [95% CI, -∞ to 0.8%]). The proportion of patients undergoing CTPA in the PERC group vs control group was 13% vs 23% (difference, -10% [95% CI, -13% to -6%]; P < .001). In the PERC group, rates were significantly reduced for the median length of emergency department stay (mean reduction, 36 minutes [95% CI, 4 to 68]) and hospital admission (difference, 3.3% [95% CI, 0.1% to 6.6%]).

CONCLUSIONS AND RELEVANCE

Among very low-risk patients with suspected PE, randomization to a PERC strategy vs conventional strategy did not result in an inferior rate of thromboembolic events over 3 months. These findings support the safety of PERC for very low-risk patients presenting to the emergency department.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02375919.

Interventions to Reduce the Overuse of Imaging for Pulmonary Embolism: A Systematic Review

BACKGROUND

Imaging use in the diagnostic workup of pulmonary embolism (PE) has increased markedly in the last 2 decades. Low PE prevalence and diagnostic yields suggest a significant problem of overuse.

PURPOSE

The purpose of this systematic review is to summarize the evidence associated with the interventions aimed at reducing the overuse of imaging in the diagnostic workup of PE in the emergency department and hospital wards.

DATA SOURCES

PubMed, MEDLINE, Embase, and EBM Reviews from 1998 to March 28, 2017.

STUDY SELECTION

Experimental and observational studies were included. The types of interventions, their efficacy and safety, the impact on healthcare costs, the facilitators, and barriers to their implementation were assessed.

DATA SYNTHESIS

Seventeen studies were included assessing clinical decision support (CDS), educational interventions, performance and feedback reports (PFRs), and institutional policy. CDS impact was most comprehensively documented. It was associated with a reduction in imaging use, ranging from 8.3% to 25.4%, and an increase in diagnostic yield, ranging from 3.4% to 4.4%. The combined implementation of a CDS and PFR resulted in a modest but significant increase in the adherence to guidelines. Few studies appraised the safety of interventions. There was a lack of evidence concerning economic aspects, facilitators, and barriers.

CONCLUSIONS

A combined implementation of an electronic CDS and PFRs is more effective than purely educational or policy interventions, although evidence is limited. Future studies of high-methodological quality would strengthen the evidence concerning their efficacy, safety, facilitators, and barriers.

The Economic Value of Hybrid Single-photon Emission Computed Tomography With Computed Tomography Imaging in Pulmonary Embolism Diagnosis

Objective

The objective was to quantify the potential economic value of single‐photon emission computed tomography (SPECT) with computed tomography (CT; SPECT/CT) versus CT pulmonary angiography (CTPA), ventilation–perfusion (V/Q) planar scintigraphy, and V/Q SPECT imaging modalities for diagnosing suspected pulmonary embolism (PE) patients in an emergency setting.

Methods

An Excel‐based simulation model was developed to compare SPECT/CT versus the alternate scanning technologies from a payer's perspective. Clinical endpoints (diagnosis, treatment, complications, and mortality) and their corresponding cost data (2016 USD) were obtained by performing a best evidence review of the published literature. Studies were pooled and parameters were weighted by sample size. Outcomes measured included differences in 1) excess costs, 2) total costs, and 3) lives lost per annum between SPECT/CT and the other imaging modalities. One‐way (±25%) sensitivity and three scenario analyses were performed to gauge the robustness of the results.

Results

For every 1,000 suspected PE patients undergoing imaging, expected annual economic burden by modality was found to be 3.2 million (SPECT/CT), 3.8 million (CTPA), 5.8 million (planar), and 3.6 million (SPECT) USD, with a switch to SPECT/CT technology yielding per‐patient‐per‐month cost savings of $51.80 (vs. CTPA), $213.80 (vs. planar), and $36.30 (vs. SPECT), respectively. The model calculated that the incremental number of lives saved with SPECT/CT was six (vs. CTPA) and three (vs. planar). Utilizing SPECT/CT as the initial imaging modality for workup of acute PE was also expected to save $994,777 (vs. CTPA), $2,852,014 (vs. planar), and $435,038 (vs. SPECT) in “potentially avoidable”’ excess costs per annum for a payer or health plan.

Conclusion

Compared to the currently available scanning technologies for diagnosing suspected PE, SPECT/CT appears to confer superior economic value, primarily via improved sensitivity and specificity and low nondiagnostic rates. In turn, the improved diagnostic accuracy accords this modality the lowest ratio of expenses attributable to potentially avoidable complications, misdiagnosis, and underdiagnosis.

Malpractice claims related to diagnostic errors in the hospital

BACKGROUND

Little is known about the incidence or significance of diagnostic error in the inpatient setting. We used a malpractice claims database to examine incidence, predictors and consequences of diagnosis-related paid malpractice claims in hospitalised patients.

METHODS

The US National Practitioner Database was used to identify paid malpractice claims occurring between 1 January 1999 and 31 December 2011. Patient and provider characteristics associated with paid claims were analysed using descriptive statistics. Differences between diagnosis-related paid claims and other paid claim types (eg, surgical, anaesthesia, medication) were assessed using Wilcoxon rank-sum and χ2 tests. Multivariable logistic regression was used to identify patient and provider factors associated with diagnosis-related paid claims. Trends for incidence of diagnosis-related paid claims and median annual payment were assessed using the Cochran-Armitage and non-parametric trend test.

RESULTS

13 682 of 62 966 paid malpractice claims (22%) were diagnosis-related. Compared with other paid claim types, characteristics significantly associated with diagnosis-related paid claims were as follows: male patients, patient aged >50 years, provider aged <50 years and providers in the northeast region. Compared with other paid claim types, diagnosis-related paid claims were associated with 1.83 times more risk of disability (95% CI 1.75 to 1.91; p<0.001) and 2.33 times more risk of death (95% CI 2.23 to 2.43; p<0.001) than minor injury, after adjusting for patient and provider characteristics. Inpatient diagnostic error accounted for $5.7 billion in payments over the study period, and median diagnosis-related payments increased at a rate disproportionate to other types.

CONCLUSION

Inpatient diagnosis-related malpractice payments are common and more often associated with disability and death than other claim types. Research focused on understanding and mitigating diagnostic errors in hospital settings is necessary.

Simplified diagnostic management of suspected pulmonary embolism (the YEARS study): a prospective, multicentre, cohort study

BACKGROUND

Validated diagnostic algorithms in patients with suspected pulmonary embolism are often not used correctly or only benefit subgroups of patients, leading to overuse of computed tomography pulmonary angiography (CTPA). The YEARS clinical decision rule that incorporates differential D-dimer cutoff values at presentation, has been developed to be fast, to be compatible with clinical practice, and to reduce the number of CTPA investigations in all age groups. We aimed to prospectively evaluate this novel and simplified diagnostic algorithm for suspected acute pulmonary embolism.

METHODS

We did a prospective, multicentre, cohort study in 12 hospitals in the Netherlands, including consecutive patients with suspected pulmonary embolism between Oct 5, 2013, to July 9, 2015. Patients were managed by simultaneous assessment of the YEARS clinical decision rule, consisting of three items (clinical signs of deep vein thrombosis, haemoptysis, and whether pulmonary embolism is the most likely diagnosis), and D-dimer concentrations. In patients without YEARS items and D-dimer less than 1000 ng/mL, or in patients with one or more YEARS items and D-dimer less than 500 ng/mL, pulmonary embolism was considered excluded. All other patients had CTPA. The primary outcome was the number of independently adjudicated events of venous thromboembolism during 3 months of follow-up after pulmonary embolism was excluded, and the secondary outcome was the number of required CTPA compared with the Wells' diagnostic algorithm. For the primary outcome regarding the safety of the diagnostic strategy, we used a per-protocol approach. For the secondary outcome regarding the efficiency of the diagnostic strategy, we used an intention-to-diagnose approach. This trial is registered with the Netherlands Trial Registry, number NTR4193.

FINDINGS

3616 consecutive patients with clinically suspected pulmonary embolism were screened, of whom 151 (4%) were excluded. The remaining 3465 patients were assessed of whom 456 (13%) were diagnosed with pulmonary embolism at baseline. Of the 2946 patients (85%) in whom pulmonary embolism was ruled out at baseline and remained untreated, 18 patients were diagnosed with symptomatic venous thromboembolism during 3-month follow-up (0·61%, 95% CI 0·36-0·96) of whom six had fatal pulmonary embolism (0·20%, 0·07-0·44). CTPA was not indicated in 1651 (48%) patients with the YEARS algorithm compared with 1174 (34%) patients, if Wells' rule and fixed D-dimer threshold of less than 500 ng/mL would have been applied, a difference of 14% (95% CI 12-16).

INTERPRETATION

In our study pulmonary embolism was safely excluded by the YEARS diagnostic algorithm in patients with suspected pulmonary embolism. The main advantage of the YEARS algorithm in our patients is the absolute 14% decrease of CTPA examinations in all ages and across several relevant subgroups.

FUNDING

This study was supported by unrestricted grants from the participating hospitals.