Right heart thrombi in pulmonary embolism: results from the International Cooperative Pulmonary Embolism Registry.

OBJECTIVES This study was designed to investigate the prevalence and prognostic significance of right heart thrombi (RHTh) in pulmonary embolism. BACKGROUND Most reports about patients with RHTh are small case series. We analyzed data referring to RHTh among 2,454 consecutive pulmonary embolism patients enrolled in the International Cooperative Pulmonary Embolism Registry. METHODS Of the 2,454 patients, 1,113 had results available from baseline echocardiography. We compared the 42 patients with RHTh versus 1,071 without RHTh. RESULTS Patients with RHTh had shorter duration of symptoms (2.2 +/- 2.9 days vs. 4.3 +/- 6.0 days, p = 0.013), lower systolic blood pressure (BP) (116.0 +/- 28.8 vs. 125.7 +/- 25.0 mm Hg, p = 0.008), and more frequent right ventricular hypokinesis (64% vs. 40%, p = 0.002) and congestive heart failure (26% vs. 13%, p = 0.024); but they had similar age (62.9 vs. 62.5 years), arterial oxygen pressure (71.3 +/- 26.0 vs. 69.5 +/- 30.5 mm Hg), and prevalence of cancer (14% vs. 19%). The overall mortality rate at 14 days and at three months was higher in patients with RHTh (21% vs. 11%, p = 0.032, and 29% vs. 16%, p = 0.036). The difference in early mortality was observed almost entirely within the subgroup of patients treated with heparin alone (23.5% vs. 8%, p = 0.02), despite similar clinical severity at presentation (systolic BP 122.2 +/- 24.2 vs. 127.8 +/- 24.1 mm Hg, hypotension in 5.9% vs. 3.4% patients). CONCLUSIONS Among patients with acute pulmonary embolism, RHTh is usually found in those more hemodynamically compromised but is also a marker of worse prognosis in initially apparently stable patients treated with heparin alone.