Pulmonary emboli may be classified according to the physiologic effects as High risk (catastrophic or super-massive): Impaired right ventricular function with severe hypotension / hypoxemia that requires aggressive pressor therapy and high-flow oxygen High risk (massive): Impaired right ventricular function causing hypotension, as defined by systolic blood pressure < 90 mm Hg or a drop in systolic blood pressure of ≥ 40 mm Hg from baseline for a period of 15 minutes Intermediate risk (submassive): Impaired right ventricular function and / or abnormal troponin and / or brain (B-type) natriuretic peptide (BNP) level without hypotension.