Symptomatic subsegmental versus more central pulmonary embolism: Clinical outcomes during anticoagulation

Subsegmental Pulmonary Embolism

Subsegmental pulmonary embolism (SSPE) is increasingly diagnosed with the growing use and technological advancements of multidetector computed tomography pulmonary angiography. Its diagnosis is challenging, and some presumed SSPE may actually represent imaging artifacts. Indirect evidence and results from small observational studies suggest that SSPE may be more benign than more proximal pulmonary embolism, and may thus not always require treatment. Therefore, guidelines suggest to consider a management strategy without anticoagulation in selected patients with SSPE at low risk of recurrent venous thromboembolism (VTE), in whom proximal deep vein thrombosis is excluded. Recently, a large prospective study among low-risk patients with SSPE who were left untreated showed a higher VTE recurrence risk than initially deemed acceptable by the investigators, and thus was prematurely interrupted after recruitment of 97% of the target population. However, the risk-benefit ratio of anticoagulation for low-risk patients with SSPE remains unclear, and results from randomized trials are needed to answer the question about their optimal management.

Clinical features and risk factors of adverse clinical outcomes in central pulmonary embolism using machine learning analysis

BACKGROUND

In prior studies, central pulmonary embolism (PE) was associated with high clot burden and was considered an independent predictor for thrombolysis. Further information about predictors of adverse outcomes in these patients is needed for better risk stratification. The objective is to describe independent predictors of adverse clinical outcomes in patients with central PE.

METHODS

Large retrospective, observational, and single-center study of hospitalized patients with central PE. Data were gathered on demographics, comorbidities, clinical features on admission, imaging, treatments, and outcomes. Multivariable standard and Least Absolute Shrinkage and Selection Operator (LASSO) machine learning logistic regressions and sensitivity analyses were used to analyze factors associated with a composite of adverse clinical outcomes, including vasopressor use, mechanical ventilation, and inpatient mortality.

RESULTS

A total of 654 patients had central PE. The mean age was 63.1 years, 59% were women, and 82% were African American. The composite adverse outcome was observed in 18% (n = 115) of patients. Serum creatinine elevation (odds ratio [OR] = 1.37, 95% CI = 1.20-1.57; p = 0.0001), white blood cell (WBC) count elevation (OR = 1.10, 95% CI = 1.05-1.15; p < 0.001), higher simplified pulmonary embolism severity index (sPESI) score (OR = 1.47, 95% CI = 1.18-1.84; p = 0.001), serum troponin elevation (OR = 1.26, 95% CI 1.02-1.56; p = 0.03), and respiratory rate increase (OR = 1.03, 95% CI = 1.0-1.05; p = 0.02) were independent predictors of adverse clinical outcomes.

CONCLUSION

Among patients with central PE, higher sPESI score, WBC count elevation, serum creatinine elevation, serum troponin elevation, and respiratory rate increase were independent predictors of adverse clinical outcomes. Right ventricular dysfunction on imaging and saddle PE location did not predict adverse outcomes.

Management of single subsegmental pulmonary embolism: a prospective observational study at North Shore and Waitakere Hospitals, Auckland

BACKGROUND

Single subsegmental pulmonary embolism is increasingly diagnosed but the benefit to anticoagulate in the absence of concurrent deep vein thrombosis is not consistently established.

AIMS

To investigate the safety of an observational approach in patients with isolated subsegmental pulmonary embolism and the utility of the second lower limb ultrasound after 7 days.

METHODS

Prospective observational study of patients diagnosed with isolated subsegmental pulmonary embolism between July 2016 and July 2020 at North Shore and Waitakere Hospitals, Auckland. The primary outcome was the venous thromboembolism recurrence rate within 3 months of single subsegmental pulmonary embolism diagnosis. Secondary outcomes included all-cause mortality, bleeding complications and the percentage of deep vein thrombosis diagnosed at serial compressive ultrasounds (CUS) of lower limbs.

RESULTS

Among the 48 patients studied (two excluded due to revised diagnosis), no statistically significant differences were found in the baseline characteristics between the anticoagulated (n = 17) and observed (n = 31) groups. After patients with deep vein thrombosis were excluded, comparisons did not reveal significant differences in the primary outcome (0 vs 1 recurrent venous thromboembolism in the anticoagulated vs. observational groups respectively) and the secondary outcomes. In the observational cohort, 77.4% (n = 24) patients had repeat bilateral lower limb CUS after 7 days, and none had deep vein thrombosis diagnosed on the second CUS.

CONCLUSIONS

Withholding anticoagulation was a feasible management option for this cohort of patients with single subsegmental pulmonary embolisms with an absence of deep vein thrombosis. The utility of a second lower limb ultrasound is questionable and would warrant further assessment in a prospective study.

A multicentre observational study of the prevalence, management, and outcomes of subsegmental pulmonary embolism

BACKGROUND

The incidence of subsegmental pulmonary embolism (SSPE) has increased with improvements in imaging technology. There is clinical equipoise for SSPE treatment, with conflicting evidence of improved mortality or reduced venous thromboembolism recurrence with anticoagulation. SSPE studies have significant heterogeneity and often lack adequately matched disease comparator groups.

OBJECTIVES

To determine the prevalence, management, and outcomes of SSPE and compare them to patients with main, lobar, segmental, and no pulmonary embolism (PE).

PATIENTS/METHODS

All adult patients undergoing CT pulmonary angiography (CTPA) between 2013 and 2019, at 3 UK hospitals were included in the study. CTPA reports were text mined for language relating to PE, and then further manually screened for the presence and anatomical location of PE. Patient groups were propensity matched by age, sex, and year of CTPA prior to analysis. 3-month outcomes of major bleeding, VTE recurrence, and death were recorded.

RESULTS

79 (3.8%) SSPEs were identified from 2,055 diagnoses of PE, and 14,300 CTPA reports. 44 (56%) of SSPEs were single artery emboli, 25 (32%) were multiple unilateral emboli, and 10 (13%) were multiple bilateral emboli. Mortality, VTE recurrence and major bleeding were similar at 3 months across all groups. 87.3% of SSPE imaging reports had an additional radiological diagnosis, with pleural effusion (30%), consolidation (19%), and cardiomegaly (19%) being the most common.

CONCLUSION

The prevalence of SSPE was 3.8% of all PEs and there were a substantial number of additional radiological findings in the SSPE group that may have accounted for their symptoms.

Influence of using recommended radiological criteria on MDCT-angiography diagnosis of single isolated subsegmental pulmonary embolism

OBJECTIVES

We assessed the rate of false-positive diagnoses of MDCT-pulmonary angiography (MDCT-A) in patients with single isolated subsegmental pulmonary embolism (SISSPE).

METHODS

All patients who underwent MDCT-A between 2006 and 2017 for ruling out acute pulmonary embolism (PE) and received an initial diagnosis of SISSPE were included. The MDCT-A of these patients were reviewed retrospectively by four experienced thoracic radiologists, who applied radiological criteria recommended by the American College of Chest Physicians Antithrombotic Guidelines (ACCP 2016) for the diagnosis of SISSPE. Data extracted from medical records were history of venous thromboembolism (VTE), alternative diagnoses, other diagnostic studies for VTE, anticoagulation, bleeding complications, and VTE over the following 3 months.

RESULTS

Of 3839 patients undergoing MDCT-A, PE was found in 1021 (26.6%) and SISSPE in 59 (1.5% overall and 5.8% of all patients with PE). An alternative diagnosis to PE was made on the basis of CT in 33 (55.9%) patients. Forty-one (69.5%) patients received anticoagulants, and major life-threatening bleeding complications occurred in 2, with one death. Recurrent PE was not documented in any patient with SISSPE. In the retrospective assessment of the 59 cases of SISSPE, 21 were negative for PE, with a false-positive rate of 35.6% (21/59); so the percentage of SISSPE cases after the revision was 3.7% of all patients with PE; 11 of these 21 patients received anticoagulation.

CONCLUSIONS

Radiologists should be aware of the high rate of false-positives when making the diagnosis of SISSPE on MDCT-A without using strict diagnostic criteria. Misdiagnosis exposes patients to unnecessary anticoagulation.

KEY POINTS

• Radiologist should be aware of the high rate of false-positive diagnoses of single isolated subsegmental pulmonary embolism (SISSPE) in MDCT-pulmonary angiography (MDCT-A) performed for ruling out pulmonary embolism. • Misdiagnosis of SISSPE in MDCT-A can be reduced by using strict diagnostic radiological criteria recommended by the American College of Chest Physicians Antithrombotic Guidelines. • Unnecessary anticoagulation therapy with potential severe bleeding complications may result from misdiagnosis of SISSPE.

Challenges in Managing Isolated Subsegmental Pulmonary Embolism

This commentary explores the clinical conundrums arising when caring for patients with acute pulmonary embolism isolated to the subsegmental pulmonary arteries. We discuss ways to confirm the radiologic diagnosis, how to distinguish patients for whom anticoagulation is indicated from those who are eligible for structured surveillance without anticoagulation, what surveillance entails, and why ensuring continuity of care matters. We report a case from our own experience that illustrates these decision-making crossroads and highlights the importance of cross-disciplinary collaboration. Because the evidence in the literature is currently weak and indirect, we draw on expert opinion in US and European guidelines, a recent statement from a multidisciplinary consensus panel, and several ongoing well-designed clinical trials. This discussion will help clinicians better manage the spectrum of patients who present with isolated subsegmental embolism.

Incidence and clinical profile of venous thromboembolism in hospitalized COVID-19 patients from Madrid region

Background

COVID-19 related in-hospital venous thromboembolism (VTE) incidence is high but data reported vary significantly. Some studies show that up to half of the events are diagnosed early after admission.

Objectives

To study symptomatic VTE incidence in acute COVID-19 hospitalized patients and to describe timing of VTE diagnosis.

Methods

Multicenter cohort of 5966 patients hospitalized with acute COVID-19. Multicenter Registry of 844 hospitalized patients with acute COVID-19 and associated acute VTE.

Results

By the time of cohort data collection, 68 patients (1.14%) were still hospitalized, 19.8% had died, and 5.4% required ICU. During a median follow-up of 6 days (IQR, 4–12), 183 patients (3.07%; 95% CI, 2.64–3.55) presented a symptomatic VTE event. The cumulative incidences of VTE at 7, 14 and 21 days in wards [2.3% (95% CI, 1.9–2.7), 3.6% (95% CI, 3.0–4.3), and 4.3% (95% CI, 3.5–5.1)] were similar to the ones reported in ICU [2.2% (95% CI, 1.0–4.4), 2.9% (95% CI, 1.5–5.3), and 4.1% (95% CI, 2.2–6.8)], but at 30 and 60 days were higher in ICU [6.9% (95% CI, 4.2–10.5), and 12.8% (95% CI, 8.1–18.5)] than in wards. Eighty-eight VTE events (48%) were diagnosed early, within 48 h of admission. VTE was not associated with death (HR, 0.79; 95% CI, 0.55–1.12).

Conclusions

Incidence of symptomatic VTE in our COVID-19 cohort is consistent with that of other real-life studies recently published. Early VTE events are, along with COVID-19, the reason for admission rather than an in-hospital complication.