Right ventricular pressure overload related to residual thrombotic burden in patients 1 year after acute pulmonary embolism: From the Nagoya PE study.

INTRODUCTION: Residual pulmonary thrombus is an important factor affecting long-term prognosis after acute pulmonary embolism (PE). In this sub-analysis of the Nagoya PE study, we aimed to evaluate the relationship between residual thrombi detected by our refined computed tomography (CT) imaging protocol and the results of a multifaceted assessment of patients 1 year after acute PE. MATERIALS AND METHODS: The Nagoya PE study was a prospective observational study of patients diagnosed with acute PE. At 1 year, patients were evaluated multifacetedly, including by enhanced CT using our refined protocol. RESULTS AND CONCLUSION: Forty-three patients completed full testing at 1 year. Patients were divided into three groups according to the modified CT obstruction index (mCTOI): no pulmonary thrombus, low mCTOI, and high mCTOI. At baseline, left ventricular end-diastolic dimension and tricuspid regurgitation (TR) pressure gradient differed significantly across the three groups. At 1 year, patients with TR velocity > 2.8 m/s were found only in the high mCTOI group (P = .022). No difference was observed in symptoms, exercise tolerance, and quality of life score. Multivariate regression analysis revealed that TR velocity > 2.8 m/s (P = .001) and change in oxygen saturation during a 6-min walking test (P = .043) at 1 year were significantly related to mCTOI at 1 year. High thrombotic burden might be detected in patients with right ventricular pressure overload at diagnosis of acute PE or after 1 year. These patients should be carefully and multifacetedly assessed for potential chronic thromboembolic pulmonary disease or chronic thromboembolic pulmonary hypertension.