Massive pulmonary embolism: A comparison of radiological and clinical characteristics and outcomes

Study objectives: To describe the clinical features of radiographically massive pulmonary embolism (MPE). Design: Retrospective analysis. Setting: A 1,368-bed teaching hospital. Patients or participants: Patients with pulmonary embolism between June 1997 and December 1999. Interventions: Radiographic reports of patients with a radiographic diagnosis of pulmonary embolism were reviewed to determine whether MPE (>50% vascular occlusion) was present. For patients with MPE, vital signs, respiratory and cardiac symptoms, medical history, arterial blood gases, electrocardiographic (ECG) and echocardiographic results, treatment, and hospital mortality were recorded. Measurements and results: Fifty-four patients with MPE were identified. Patient age range was 28-91 years (mean 71 years). Symptoms were: dyspnea in 38 (70%), chest pain in 21 (38%), syncope in 12 (22%), palpitations in 6 (11%), systolic blood pressure < 90 mmHg in 12 (22%), tachycardia (>120 beats/min) in 15 (28%) and tachypnea (respiratory rate > 30) in 15 (28%). Pao₂ (arterial partial pressure of oxygen) was less than 60 mmHg in 28 (71%) and the alveolar-arterial oxygen gradient was always greater than 20. ECG had an S1Q3T3 pattern in 6 (12%). Echocardiography revealed right ventricular dilatation in 12/31 (38%). Forty-nine patients received anticoagulation treatment, 4 (7%) received thrombolytic therapy with anticoagulation, 5 had inferior vena cava filters (IVC) alone, 6 received IVC filters with anticoagulation, and 2 received thrombolytic therapy, anticoagulation, and IVC filters. Eighteen (33%) patients were treated in the intensive care unit, 3 (5.5%) with mechanical ventilation. Fifty (93%) patients were eventually discharged and 4 (7%) died. Two of the deaths were not attributable to MPE. Conclusions: Patients with MPE usually present with dyspnea and hypoxemia, and most survive without thrombolytic therapy.