Low Risk Meets High Stakes: Unraveling the Mystery of Low D-dimer Pulmonary Embolism

Pulmonary embolisms (PEs) are potentially life-threatening emergencies that carry significant morbidity and mortality. Advances in treatment options and the safety of existing procedures have effectively reduced the long-term and short-term effects of the condition. Therefore, it is important to make an early diagnosis so that treatment options can be thoroughly explored. The D-dimer is an important tool in the early diagnosis of PEs. It is especially useful in ruling out the diagnosis in patients with a low to moderate suspicion of the disease. We present a case of a 22-year-old male who presented with exertional dyspnea, congestion, and rhinorrhea for one day and was noted to have persistent hypoxia and tachycardia. The influenza test was positive, and he was started on oseltamivir. Due to persistent hypoxia, a CT pulmonary angiogram was ordered and revealed filling defects in the left lower lobe segmental vessels suggestive of PE, as well as multifocal multilobar bilateral ground-glass opacities. He was initially treated with a heparin drip and subsequently switched to eliquis. After a significant improvement in his hypoxia, he was discharged home for outpatient follow-up, including a hypercoagulable workup. This case demonstrates that despite the usefulness of the D-dimer as a diagnostic tool for PEs, it cannot solely or fully replace the full gamut of screening tools used to determine the risk of PE. Although rare, false-negative scores do occur; therefore, the tool should always be used in conjunction with other scoring systems, physician gestalt, and within the specific clinical context.

Left Pulmonary Artery Aneurysm: A Post-stenotic Pulmonary Aneurysm Related to Pulmonary Valve Stenosis

Aneurysms of the pulmonary artery are uncommon vascular pathologies that are associated with congenital structural cardiac anomalies, pulmonary hypertension, vasculitis, neoplasm, iatrogenic, and infection. PAAs are commonly asymptomatic and accidentally diagnosed, however, if symptomatic, clinical features are generally non-specific and depend on the etiology of PAA. CT pulmonary angiography remains the gold standard imaging modality and other diagnostic imaging tests include transthoracic echocardiography and right heart catheterization. Definitive treatment of PAA is surgery, however, conservative management with close monitoring should be practiced in patients with poor surgical candidates or surgery is unlikely to improve survival. Here, we report a case of pulmonary artery aneurysm secondary to congenital pulmonary valve stenosis as well as a brief review of the literature regarding pulmonary artery aneurysms.

Pulmonary embolism risk in hospitalized patients with nonalcoholic fatty liver disease: A case-control study

Abundant research has associated nonalcoholic fatty liver disease (NAFLD) with atherosclerosis, but very few reports have evaluated the association between NAFLD and venous thromboembolism. We aimed to investigate the association between NAFLD and pulmonary embolism (PE) in hospitalized patients. In this retrospective case-control study, we included consecutive patients from 2 university-affiliated hospitals who were referred for CT pulmonary angiograms for a suspected PE. Patients with a history of excessive alcohol consumption, chronic liver diseases or cirrhosis were excluded. The imaging studies of the entire cohort were reviewed by 2 expert radiologists who confirmed the diagnosis of PE and examined the liver to detect and grade hepatic steatosis. Accordingly, patients were categorized into NAFLD patients and non-NAFLD controls. Patient demographics, medical history, hospitalization details as well as patients' outcomes were documented. Multivariate analysis was performed to identify predictors for developing PE and hazard ratios with corresponding 95% confidence intervals were estimated. A total of 377 patients (101 with NAFLD and 276 controls) were included. NAFLD patients had significantly higher BMI values (33.16 ± 6.78 vs 26.81 ± 5.6; P < .001) and prevalence of diabetes (41 (40%) vs 85 (30.8%); P = .03). The prevalence of PE was significantly higher in the NAFLD group (80 (79.2%) vs 147 (53.3%), P < .001). In a multivariate analysis, older age, recent surgery or trauma, active malignancy, smoking, and NAFLD (HR ratio = 4.339, P < .0001 and 95% CI = 2.196-8.572) were independently associated with PE development. Patients with NAFLD were associated with an increased risk of developing PE independent of other classical risk factors for PE.

CTPA pulmonary artery distensibility in assessment of severity of acute pulmonary embolism and right ventricular function

To investigate the characteristics of pulmonary artery distensibility (PAD) in patients with acute pulmonary embolism (APE) and to assess the correlation of PAD with APE severity and right ventricular function. A total of 33 patients who underwent retrospective electrocardiogram (ECG)-gated computed tomography pulmonary angiography (CTPA) with a definite diagnosis of APE were included in the study. According to APE severity, the patients were divided into severe (SPE) and non-severe (NSPE) groups. Data from a control group without APE matching the basic demographics of the APE patients were collected. Pulmonary artery distensibility (PAD) and right ventricular function parameters were compared among the 3 groups, their relationships were investigated, and receiver operating characteristic (ROC) curves were used to determine the sensitivity and specificity of the above parameters for the diagnosis of APE severity. The PAD values of the control, NSPE, and SPE groups were (7.877 ± 2.637) × 10-3 mm/Hg, (6.050 ± 2.011) × 10-3 mm/Hg, (4.321 ± 1.717) × 10-3 mm/Hg, respectively (P < .01). There were statistically significant differences in right ventricular function parameters among the 3 groups (P < .05). The correlation analysis between PAD and right ventricular function parameters showed a weak negative correlation (r = -0.281--0.392). The area under the ROC curve of PAD was 0.743, the critical value was 4.200, and the sensitivity and specificity were 62.5% and 94.1%, respectively. The PAD obtained by retrospective ECG-gated CTPA could accurately evaluate APE severity and right ventricular function. As the severity of APE increases, PAD decreases, which is helpful to identify patients at high risk of APE.

Sickle cell disease and venous thromboembolism: A retrospective comparison of the rate of positive CT pulmonary angiography in the emergency department

BACKGROUND

Previous authors have reported an increased incidence of acute pulmonary embolism (PE) in patients with sickle cell disease (SCD) based on retrospective analysis of ICD codes. It is unknown whether patients with SCD have higher rates of positive CT pulmonary angiogram (CTPA) in the emergency department (ED).

METHODS

The institutional review board (IRB) approved this retrospective study; informed consent was waived. Between January 1, 2005 and May 31, 2015, 28 patients with SCD underwent a total of 78 CTPA studies in the ED. A control group of 75 non-SCD patients matched for age, gender and race underwent 78 consecutive CTPA studies in the emergency department. Modified Wells' (mWells') scores were calculated for each CTPA study performed. The studies for both groups were blind read by two fellowship trained body radiologists. Descriptive statistics were performed, with significance considered if p < 0.05.

RESULTS

The rate of positive CT pulmonary angiogram in patients with SCD was 6.4% (5/78), compared with 12.8% (10/78) in non-SCD matched controls. There was no significant difference in the rate of positive CTPA (p = 0.277). There was also no difference in the mean mWells' score between the two groups (2.44 for SCD vs. 1.95 for controls, p = 0.120).

CONCLUSION

SCD patients did not have a significantly different rate of acute PE when compared with matched controls undergoing CTPA in the ED.

Assessment of pulmonary arterial enhancement on CT pulmonary angiography using a leg vein for contrast media administration

The purpose of our study was to compare pulmonary artery (PA) enhancement according to venous routes of contrast media (CM) administration in patients who underwent CT pulmonary angiography (CTPA) in the emergency department (ED).This retrospective study reviewed the CTPAs of 24 patients who administered CM via leg veins (group A) and 72 patients via arm veins (group B) with age and gender matching at a ratio of 1:3. Clinical data, aorta attenuation (Aoatten), and PA attenuation (PAatten) were compared between group A and B. Each group was subcategorized into diagnostic and nondiagnostic CTPA subgroups, with a threshold of 250 HU at the PA. Then, clinical data, rates of pulmonary embolism (PE), and right ventricle (RV) strain were compared. In group A, the relationship between the narrowest suprahepatic IVC area (IVCarea) and the attenuation ratio of the RV to the intrahepatic IVC (RV/IVCatten) was evaluated.Aoatten (236.6 HU vs 293.1 HU, P < .001) and PAatten (266.7 HU vs 321.4 HU, P = .026) were significantly lower in group A than in group B. The proportion of nondiagnostic CTPA was significantly higher in group A than in group B (58.3% vs 19.4%, P = .001). In the subgroup analysis in of group A, patients with a nondiagnostic CTPA were significantly younger (55.3 years vs 68.6 years, P = .026) and showed a significantly lower incidence rate of PE (14% vs 70%, P = .01) than patients with a diagnostic CTPA. However, the radiological diagnostic rate of RV strain was comparable between patients with nondiagnostic and diagnostic CTPA. In group A, IVCarea and RV/IVCatten were positively correlated, with a correlation coefficient of 0.430 (P < .036).In conclusion, administration of CM through the leg veins increases the nondiagnostic CTPA rate, reducing the detection rate of PE. When CM is injected via the leg veins, the degree of PA enhancement is related with to the diameter of the suprahepatic IVC; therefore, adjustment of respiratory maneuvers may be needed to promote IVC flow into the right cardiac chamber, and to improve PA enhancement.