Thrombolytic Therapy in Unstable Patients With Acute Pulmonary Embolism

Study Questions:

Does thrombolytic therapy reduce case fatality rate in unstable patients with acute pulmonary embolism (PE)?

Methods:

The authors analyzed data from the Nationwide Inpatient Sample for the years 1999 to 2008. They used ICD-9 codes to identify patients with PE by discharge diagnosis. Patients were classified as unstable based on the diagnosis of shock or ventilator use. Case fatality rates for various groups were compared.

Results:

The authors reported that thrombolytic therapy was given to the minority of unstable patients with PE: 21,390 of 72,230 (30%). In-hospital all-cause case fatality rate was lower in unstable patients given thrombolytic therapy: 3,105 of 20,390 (15%) versus 23,820 of 50,840 (47%) of those receiving versus not receiving thrombolytic therapy, respectively (p < 0.0001). Those unstable patients receiving thrombolytic therapy plus vena cava filter had a lower case fatality rate than those unstable patients receiving filter alone: 505 of 6,630 (7.6%) versus 4,260 of 12,850 (33%); p < 0.0001. Thrombolytic therapy was associated with a reduction in case fatality rate attributable to PE in unstable patients: 820 of 9,800 and (8.4%) versus 1,080 of 2,600 (42%); p < 0.0001. Vena cava filter was associated with a reduction in case fatality rate attributable to PE when added to thrombolytic therapy in unstable patients: 70 of 2,590 (2.7%) versus 160 of 600 (27%); p < 0.0001.

Conclusions:

The authors concluded that in-hospital all-cause case fatality rate and case fatality rate attributable to PE in unstable patients was lower in those who received thrombolytic therapy. Thrombolytic therapy resulted in lower case fatality rate than using vena cava filters alone, and the combination resulted in an even lower case fatality rate. The authors further opined that thrombolytic therapy in combination with a vena cava filter in unstable patients with acute PE seems indicated.

Perspective:

Although this study suffers from the limitation of being observational in nature, and using a database not designed for this purpose, the large number of subjects and the comprehensive study population strongly suggest that a significant reduction in mortality is associated with the use of thrombolytic therapy in unstable patients with PE, which was even lower when this therapy was combined with vena cava filters. Current guidelines both in the United States and Europe have recommended the use of thrombolytic therapy in unstable patients with PE. These data strongly confirm that. They also suggest a survival benefit when vena cava filters are combined with thrombolytic therapy in unstable patients. This finding significantly reframes the discussion about indications for vena cava filters. Currently, the guidelines define the candidacy for vena cava filter therapy based on failure of or contraindications to anticoagulant therapy for DVT and PE. This study suggests that candidacy for vena cava filters in patients with PE might be based on presence of clinical instability in the same way that candidacy for thrombolytic therapy is determined.

Clinical Topics: Dyslipidemia, Vascular Medicine, Lipid Metabolism

Keywords: Minority Groups, Thrombolytic Therapy, Vena Cava Filters, International Classification of Diseases, Shock, Pulmonary Embolism, Cardiovascular Diseases, Parkinson Disease, Europe, Tissue Plasminogen Activator, United States


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