Saddle pulmonary embolism is not a sign of high-risk deterioration in non-high-risk patients: A propensity score-matched study

BACKGROUND: There is controversy regarding whether saddle main pulmonary artery (MPA) embolism represents a high risk of deterioration in non-high-risk acute pulmonary embolism (PE) patients. This study aims to address this issue by conducting a propensity score matching (PSM) study. METHODS: A total of 727 non-high-risk acute PE patients were retrospectively evaluated. We evaluated the Bova score and risk stratification to examine the risk of deterioration. Deterioration defined as any adverse event within 30 days after admission. Computed tomographic pulmonary angiography was used to identify the embolism type. All patients were matched into four subgroups by PSM according to age, sex, Bova score, and risk stratification: (1) MPA and non-MPA embolism; (2) non-saddle MPA and non-MPA embolism; (3) saddle MPA and non-saddle MPA embolism; (4) saddle MPA and non-MPA embolism. Correlations were analyzed using Cox regression analysis, and deterioration risk was compared between subgroups using Kaplan-Meier analysis. RESULTS: Cox regression analysis revealed that MPA embolism was correlated with deterioration, regardless of whether saddle MPA embolism was included or excluded. Saddle MPA embolism was not correlated with deterioration, regardless of comparison with non-saddle MPA embolism or non-MPA embolism. Patients with MPA and non-saddle MPA embolism presented a high risk for deterioration (log-rank test=5.23 and 4.70, P=0.022 and 0.030, respetively), while patients with saddle MPA embolism were not at a high risk of deterioration (log-rank test=1.20 and 3.17, P=0.729 and 0.077, respetively). CONCLUSIONS: Saddle MPA embolism is not indicative of a high risk of deterioration in non-high-risk acute PE patients.