Single versus multiple and incidental versus symptomatic subsegmental pulmonary embolism: clinical characteristics and outcome

Isolated subsegmental pulmonary embolism identification based on international classification of diseases (ICD)-10 codes and imaging reports

BACKGROUND

Isolated subsegmental pulmonary embolism (issPE) is a commonly encountered diagnosis. Although the International Classification of Diseases (ICD)-10 codes are used for research, their validity for identifying issPE is unknown. Moreover, issPE diagnosis is challenging, and the findings from radiology reports may conflict with those from expert radiologists.

METHODS

Based on prespecified criteria, 1734 medical records of adult patients hospitalized within the Mass General Brigham health system (2016-2021) were selected in three equal groups: (1) patients with principal discharge diagnosis codes for PE, (2) patients with secondary discharge diagnosis codes for PE, and (3) patients with no PE codes. The accuracy of ICD-10 codes for issPE was verified by two independent physicians and weighted by total hospitalizations. In a randomly selected sample of 70 patients, the accuracy of initial radiology reports was determined through a blinded re-evaluation by two expert radiologists.

RESULTS

In weighted estimates, ICD-10 codes in primary or secondary discharge positions, compared with chart reviews, showed a low sensitivity (7.0 %) and positive predictive value (25.2 %). Evaluation by two expert radiologists noted that initial radiology reports were sensitive (97.1 %) for issPE but had a low specificity (40.0 %). Two (3.6 %) out of 55 patients with initial issPE reports did not have PE, while 19 (34.5 %) had more proximal PE.

CONCLUSIONS

ICD-10 codes for issPE have poor sensitivity and positive predictive value and should not be used for research or quality improvement. Radiology reports for issPE may be inaccurate regarding the location or, less often, the presence of PE.

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 Surveillance vs Anticoagulation Therapy for Isolated Subsegmental Pulmonary Embolism: A Systematic Review of Clinical Outcomes

BACKGROUND

This systematic review aims to evaluate and compare differences in clinical outcomes for adult patients diagnosed with ISSPE who were managed with anticoagulation vs clinical surveillance.

METHODS

PubMed, Embase, ProQuest, Cochrane, and Google Scholar were searched to identify studies evaluating the use of anticoagulation and/or clinical surveillance in patients diagnosed with ISSPE. The search included studies published up to August 3, 2023. Outcomes of interest included 90-day recurrent venous thromboembolism (VTE), major bleeding, and all-cause mortality rates.

RESULTS

Ten studies were included with a total of 1224 patients. Of these patients, 791 were treated with anticoagulation and 433 underwent surveillance. Studies found no difference in recurrent VTE rates, with the majority of studies reporting no recurrence. Of the studies that reported VTE recurrence, rates were .5% to 1.4% for the anticoagulation groups and 3.1% to 3.2% for the surveillance groups. Major bleeding rates were also similar. In anticoagulated patients, major bleeding rates ranged from 1% to 10%. In clinical surveillance patients, the majority found no rate of major bleeding, with 2 studies reporting rates of .8% to 3.2%. Mortality rates ranged widely with no significant differences reported.

CONCLUSION

Clinical surveillance appears to be a safe and effective alternative to anticoagulation in patients with ISSPE. Ninety-day rates of recurrent VTE, major bleeding, and mortality were comparable between groups. These findings highlight the need for updated practice management guidelines to improve patient outcomes.

Prognosis of incidental pulmonary embolism vs. symptomatic pulmonary embolism in cancer patients: a single-center retrospective cohort study in China

BACKGROUND

The incidence of incidental pulmonary embolism (IPE) has greatly increased, but its clinical characteristics and outcomes are still controversial. This study aimed to compare the clinical characteristics and outcomes between cancer patients with IPE and patients with symptomatic pulmonary embolism (SPE).

PATIENTS/METHODS

Clinical data of 180 consecutive patients with cancer complicated with pulmonary embolism admitted to Beijing Cancer Hospital from July 2011 to December 2019 were retrospectively collected and analysed. General characteristics, diagnosis time of pulmonary embolism (PE), location of PE, concurrent deep venous thrombosis, anticoagulant treatment, impact of PE on anti-tumor treatment, recurrent venous thromboembolism, rate of bleeding after anticoagulation therapy, survival and risk factors of IPE were compared with SPE.

RESULTS

Of 180 patients, 88 (49%) had IPEs and 92 (51%) had SPEs. Patients with IPE and SPE did not differ in age, sex, tumor type, or tumor stage. Median diagnosis times of IPE and SPE after cancer were 108 (45, 432) days and 90 (7, 383) days, respectively. Compared to SPE, IPE tended to be central (44% versus 26%; P < 0.001), isolated (31.8% versus 0.0%; P < 0.001), and unilateral (67.1% versus 12.8%; P < 0.00). The rate of bleeding after anticoagulation therapy did not differ between IPE and SPE. Patients with IPE had a better prognosis than patients with SPE in terms of 30-, and 90-day mortality, as well as overall survival after diagnosis of PE (median: 314.5 vs. 192.0 days, log-rank P = 0.004) and cancer (median: 630.0 vs. 450.5 days, log-rank P = 0.018). SPE (compared to IPE) was an independent risk factor for poor survival after diagnosis of PE in multivariate analysis (hazard ratio [HR] = 1.564, 95% confidence interval [CI]: 1.008-2.425, p = 0.046).

CONCLUSIONS

IPE accounts for nearly one half of PE cases among Chinese cancer patients. With active anticoagulation treatment, IPE is expected to achieve better survival rates than SPE.

Clinical Significance and Outcome in Patients with Asymptomatic Versus Symptomatic Subsegmental Pulmonary Embolism

The clinical significance and optimal therapy of patients with subsegmental pulmonary embolism (SSPE) remain controversial. We used the data in the RIETE Registry to compare the baseline characteristics, treatment, and outcomes during anticoagulation and after its discontinuation in patients with asymptomatic vs. symptomatic SSPE. From January 2009 to September 2022, there were 2135 patients with a first episode of SSPE, of whom 160 (7.5%) were asymptomatic. Most patients in both subgroups received anticoagulant therapy (97% vs. 99.4%, respectively). During anticoagulation, 14 patients developed symptomatic pulmonary embolism (PE) recurrences, 28 lower-limb deep vein thrombosis (DVT), 54 bled, and 242 died. The patients with asymptomatic SSPE had similar rates of symptomatic PE recurrences (hazard ratio (HR): 2.46; 95% CI: 0.37-9.74), DVT (HR: 0.53; 95% CI: 0.03-2.80), or major bleeding (HR: 0.85; 95% CI: 0.21-2.42) to those with symptomatic SSPE, but had a higher mortality rate (HR: 1.59; 95% CI: 1.25-2.94). The rate of major bleeding outweighed the rate of PE recurrences (54 major bleeds vs. 14 PE recurrences), and the rate of fatal bleeds outweighed the rate of fatal PE recurrences (12 vs. 6 deaths). After discontinuing anticoagulation, the patients with asymptomatic SSPE had a similar rate of PE recurrences (HR: 1.27; 95% CI: 0.20-4.55) and a non-significantly higher mortality rate (HR: 2.06; 95% CI: 0.92-4.10). The patients with asymptomatic SSPE had similar rates of PE recurrences to those with symptomatic SSPE, during and after discontinuing anticoagulation. The unexpectedly higher rate of major bleeding than recurrences highlights the need for randomized trials to find the best management.