Heart disease may be a risk factor for pulmonary embolism without peripheral deep venous thrombosis.

BACKGROUND Heart diseases increase the risk of arterial embolism; whether they increase the risk of pulmonary embolism without peripheral venous thrombosis is less certain. METHODS AND RESULTS We conducted a nationwide, population-based case-control study in Denmark using patients diagnosed with pulmonary embolism and/or deep venous thrombosis between 1980 and 2007. We computed odds ratios to estimate relative risks associating preceding heart disease with pulmonary embolism, pulmonary embolism and deep venous thrombosis, or deep venous thrombosis alone. In this study, 45,282 patients had pulmonary embolism alone, 4680 had pulmonary embolism and deep venous thrombosis, and 59,790 had deep venous thrombosis alone; 541,561 were population controls. Myocardial infarction and heart failure in the preceding 3 months conferred high risks of apparently isolated pulmonary embolism (odds ratio, 43.5 [95% confidence interval (CI), 39.6-47.8] and 32.4 [95% CI, 29.8-35.2], respectively), whereas the risks of combined pulmonary embolism and deep venous thrombosis (19.7 [95% CI, 16.0-24.2] and 22.1 [95% CI, 18.7-26.0], respectively) and deep venous thrombosis alone (9.6 [95% CI, 8.6-10.7] and 12.7 [95% CI, 11.6-13.9], respectively) were lower. Left-sided valvular disease was associated with an odds ratio of 13.5 (95% CI, 11.3-16.1), whereas the odds ratio was 74.6 (95% CI, 28.4-195.8) for right-sided valvular disease. Restricting the analysis to cases diagnosed after 2000 led to lower risk estimates but the same overall pattern. CONCLUSION Heart diseases increase the near-term risk for pulmonary embolism not associated with diagnosed peripheral vein thrombosis.