Moua and Wood right ventricular dysfunction to outcome than a diagnostic measure of PE presence. Kucher and colleagues (2003) found increased morbidity and mortality with elevated BNP and PE in patients without history of heart disease. Those needing urgent triage to more acute settings or dying shortly after their presentation had higher overall BNP levels (Kucher et al 2003). Kruger and colleagues (2004) studied 50 consecutive patients presenting with conﬁrmed PE and found those with- out right ventricular dysfunction to have signiﬁcantly lower BNP levels. A cutoff greater than 90 pg/ml was associated with a risk ratio of 28.4 for right ventricular dysfunction, though BNP was not predictive of mortality or in-hospital complication in this particular study (Kruger et al 2004). Troponin With uncomplicated COPD, troponin values are negative and helpful in ruling out acute cardiac ischemia as a cause of respiratory decompensation. Very rarely is there myocyte damage, except with severe respiratory failure and related poor oxygenation and ischemia. With PE, right ventricular dilatation increases wall tension and decreases endocardial perfusion promoting myocardial damage. Giannitsis and colleagues (2000) reported the pres- ence of troponin values greater than 0.l ng/ml as indicative of right ventricular dysfunction associated with higher morbid- ity and mortality. Meyer and colleagues (2000) proposed that nearly a third of patients presenting with clinically diagnosed pulmonary embolism have elevated troponoin – I values. This was signiﬁcantly associated with right ventricular dilatation and dysfunction as seen on echocardiography (Meyer et al 2000). Elevated troponin is absent in the setting of uncom- plicated COPD, but if present, an evaluation for underlying PE is appropriate, especially when there is absence of signs and symptoms of acute ischemia. Lower extremity doppler ultrasonography The majority of pulmonary emboli (87%–97%) originate from the lower extremities, particularly the deep veins of the thigh. A study by Winter and colleagues (1983) of 29 patients with COPD exacerbation found 13 with DVT, two of which were later found to have PE postmortem (Winter et al 1983). Of these patients, none presented with clinical signs of DVT. Erelel and colleagues (2002) followed 56 patients with hospitalized COPD and detected DVT by ultrasound in eight. Five were subsequently diagnosed with pulmonary embolism by high probability V/Q scanning (Erelel et al 2002). Ambrosetti and colleagues (2003) suggested 10% 280 of patients with COPD have concomitant DVT, though this number may far underestimate actual prevalence. The risk of DVT appears increased due to poor mobility with worsening respiratory status, chronic steroid use, and active smoking (Erelel et al 2002). Treatment guidelines for inpatient COPD exacerbations currently recommend the standard use of DVT prophylaxis (GOLD et al 2005). V/Q scan V/Q scanning remains the imaging study of choice for diagnosing PE in patients who cannot tolerate a dye load because of acute or chronic kidney disease. Unfortunately, intrinsic lung processes such as pulmonary edema, pneumo- nia or anatomical perfusion, and ventilation defects confound the presence of thromboembolism. Lesser and colleagues (1992) found 60% of scans in the setting of COPD were of intermediate probability, with 22% later diagnosed with PE by angiography. High probability scans were positive for PE (5 of 5) while low probability scans did not have simi- lar negative predictive values as compared with a general population because of increased pretest probability (Lesser et al 1992). Hartmann and colleagues (2000) concluded in a study of 509 patients with and without COPD that PE prevalence was similar between the two groups when V/Q was nondiagnostic and required angiographic conﬁrmation. An increased frequency of high and low probability scans were found compared with Lesser’s study. The utility of V/Q scanning in COPD appears diminished by a trend towards intermediate probability readings. Spiral CT/angiography Spiral chest CT and conventional angiography, the gold standards for PE diagnosis, were found by Hartmann and colleagues (2000) to have the same diagnostic performance in patients with and without COPD. Prevalence of PE appeared similar to other patient populations, suggesting equivalent sensitivity of the test and absence of association between PE and COPD. Summary and recommendations In studies evaluating PE and COPD, the presence of PE may be one in four among patients presenting with COPD exac- erbation, a rate similar to a diagnosis of one in ﬁve among all patients presenting with acute dyspnea and a high pretest probability (Hoellerich and Wigton 1986; Wells et al 1998; Mispelaere et al 2002; Tillie-Leblond et al 2006). A careful evaluation of the epidemiology of both diseases ﬁnds the prevalence of PE in COPD similar to that of other disease International Journal of COPD 2008:3(2)