Arterial phase left atrial opacification in acute massive pulmonary embolism

Classic angiographic features in acute massive pulmonary embolism include main or lobar arterial branch cut-off, and/or arterial filling defects with matching impaired venous drainage. Six haemodynamically compromised patients with acute massive pulmonary embolism (mean pulmonary artery pressure 55 +/- 12 mmHg), confirmed by pulmonary arteriography, are described. Early opacification of the left atrium during the arterial phase of the pulmonary angiogram was seen in all patients. Follow-up pulmonary arteriography after successful thrombolytic therapy was performed 4 days later in 2 cases. A marked haemodynamic improvement was accompanied by resolution of the previous abnormal angiographic signs, including early opacification of the left atrium. The latter might be a response to intensive reactive vasodilatation of the remaining perfused lung fields resulting in a more rapid pulmonary transit time and the opening of arteriovenous channels with further systemic desaturation. This angiographic sign is a marker of severe, but reversible, vasoconstriction in acute massive pulmonary embolism.