The report by Secemsky et al1 in this issue of The American Journal of Medicine illustrates the current management of pulmonary embolism at the Massachusetts General Hospital (MGH). A Pulmonary Embolism Response Team sees all patients in whom pulmonary embolism is diagnosed by computed tomography. The team manages these patients during their hospitalization and after discharge for up to 1 year.1
Secemsky et al1 report the management of 338 patients with acute pulmonary embolism. Forty-six patients (13.6%) presented with shock secondary to massive pulmonary embolism. Seventy two percent of these patients with massive pulmonary embolism and shock were treated with a variety of ‘advanced therapies’: systemic thrombolysis, catheter-directed thrombolysis, inferior cava filters, surgical embolectomy, or extracorporeal oxygenation. The in-hospital mortality of these patients with shock was 32.6%.1 The 292 patients without shock were treated with anticoagulation or inferior vena cava filter, or both. Their in-hospital mortality was 4.5%.1
It is of interest to compare this report with a similar report from another Boston hospital, the Peter Bent Brigham Hospital (PBBH).2 They reported that over a 10-year period, virtually all patients with suspected pulmonary embolism were seen by a team from the laboratory of the late Lewis Dexter. They performed pulmonary angiography and right heart catheterization in 544 patients suspected to have acute pulmonary embolism. Pulmonary embolism was confirmed by pulmonary angiography in 144 of these patients.2 Thirty-two patients (22.2%) had hypotension, compared with 13.6% in the MGH series. Anticoagulation was the primary therapy. Fifty-eight percent had inferior vena cava interruption. Only 1 patient had advanced therapy: surgical pulmonary embolectomy.
There were 20 in-hospital deaths. The in-hospital mortality in those with shock in the PBBH series2 was 34.4% compared with 32.6% in the MGH report. The in-hospital mortality without shock was 8% in the PBBH series and 4.5% in the MGH series.1, 2 The patients in the PBBH series were treated in the 10-year period from 1964 to 1974; about 50 years prior to the MGH report! One has to conclude that improvement of the treatment for massive pulmonary embolism in the past 50 years has been less than dramatic.
The report by Secemsky et al1 confirms the fact that shock is the prime indicator for advanced therapy. Evidence of right ventricular strain by imaging or by elevated troponin T or N-terminal pro-brain natriuretic peptide may help identify pulmonary embolism but are not useful in identifying patients who require advanced therapy.
Because shock is present in only about 20% of pulmonary embolism patients, it will be difficult to demonstrate which of the various advanced therapies are more effective than standard therapy with anticoagulants. It would require a massive multicentered randomized clinical trial. In the absence of shock, the mortality with anticoagulant therapy continues to be in the range of 5%. Given this low mortality, it is unlikely that a randomized trial of anticoagulant therapy vs systemic thrombolysis or catheter-directed thrombolysis could detect a therapeutic benefit in pulmonary embolism patients without shock. The most important current method to prevent fatal pulmonary embolism is prevention of venous thromboembolism in patients known to be at increased risk of deep vein thrombosis.
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-James E. Dalen, MD, MPH
This article originally appeared in the December issue of The American Journal of Medicine.
