CT Pulmonary Angiography: Increasingly Diagnosing Less Severe Pulmonary Emboli

Background

It is unknown whether the observed increase in computed tomography pulmonary angiography (CTPA) utilization has resulted in increased detection of pulmonary emboli (PEs) with a less severe disease spectrum.

Methods

Trends in utilization, diagnostic yield, and disease severity were evaluated for 4,048 consecutive initial CTPAs performed in adult patients in the emergency department of a large urban academic medical center between 1/1/2004 and 10/31/2009. Transthoracic echocardiography (TTE) findings and peak serum troponin levels were evaluated to assess for the presence of PE-associated right ventricular (RV) abnormalities (dysfunction or dilatation) and myocardial injury, respectively. Statistical analyses were performed using multivariate logistic regression.

Results

268 CTPAs (6.6%) were positive for acute PE, and 3,780 (93.4%) demonstrated either no PE or chronic PE. There was a significant increase in the likelihood of undergoing CTPA per year during the study period (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.04–1.07, P<0.01). There was no significant change in the likelihood of having a CTPA diagnostic of an acute PE per year (OR 1.03, 95% CI 0.95–1.11, P = 0.49). The likelihood of diagnosing a less severe PE on CTPA with no associated RV abnormalities or myocardial injury increased per year during the study period (OR 1.39, 95% CI 1.10–1.75, P = 0.01).

Conclusions

CTPA utilization has risen with no corresponding change in diagnostic yield, resulting in an increase in PE detection. There is a concurrent rise in the likelihood of diagnosing a less clinically severe spectrum of PEs.     

Streptokinase Therapy in Acute Major Pulmonary Embolism: Effectiveness and Problems

Eighteen patients with major pulmonary embolism were treated with streptokinase infused by a catheter or given intravenously. Fourteen showed clinical improvement and 12 out of 16 patients investigated showed definite angiographic improvement after 24 to 48 hours of treatment with streptokinase. The angiographic improvement following streptokinase contrasted with the lack of this in three patients after 24 hours of heparin treatment.Resolution following streptokinase therapy was most noticeable in patients treated shortly after a single embolic episode, and was least marked in those with recurrent embolism complicated by associated cardiac or pulmonary disease. Of the four patients who failed to improve, two died and two had pulmonary embolectomy and survived.The results suggest that streptokinase therapy is practicable provided that adequate laboratory control is available, and that it hastens early resolution in acute major pulmonary embolism.