All That Glitters Is Not Gold in Pursuing the Diagnosis of Pulmonary Embolism: Response

Abstract

We thank Drs Simons and Snijders for their interest and kind review of our recent article.1Moores LK King CS Holley AB Current approach to the diagnosis of acute nonmassive pulmonary embolism.Chest. 2011; 140: 509-518Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar It seems that we all agree that the determination of pretest probability (PTP) and D-dimer testing are important tools in the diagnostic approach to suspected pulmonary embolism (PE). Although we intended a general review without reference to special populations, Drs Simons and Snijders make a valid point that our approach may need to be modified in such groups. It is true that patients who are pregnant and the majority of patients with renal failure or insufficiency who are thought to have acute PE have been excluded from treatment trials utilizing a noninvasive approach that use PTP and D-dimer testing. As we noted, several clinical decision rules (CDRs) have been developed and validated to help physicians determine PTP. None has been validated specifically in patients with chronic kidney disease, but there is nothing in these scores, particularly the Wells CDR, that would be problematic in application to these patients. We agree with Drs Simons and Snijders that this is not the case with patients who are pregnant, who often have many of the signs and symptoms that compose the basic elements of the Wells score, independent of whether VTE is present. As we note in our review, however, the important issue is not which CDR is used, but that some assessment of PTP is made before pursuing further diagnostic testing. A CDR has been developed for suspected DVT in patients who are pregnant,2Tan M Huisman MV The diagnostic management of acute venous thromboembolism during pregnancy: recent advancements and unresolved issues.Thromb Res. 2011; 127: S13-S16Abstract Full Text PDF PubMed Scopus (15) Google Scholar although it has not been prospectively validated. A CDR for PE in these patients has not yet been developed. The use of D-dimer to exclude VTE in both of these populations is also somewhat problematic. Both populations have elevated D-dimer levels at baseline, and, thus, the clinical utility (eg, specificity, number of patients tested to rule out VTE on just one patient) is much lower. It should be stressed, however, that the sensitivity remains high in these patients. We would like to avoid imaging studies in both of these populations (because of either the risk that the contrast dye could worsen renal function or radiation risk to the fetus). Therefore, if we can exclude VTE in even a small number of patients, it would still be helpful.3Karami-Djurabi R Klok FA Kooiman J Velthuis SI Nijkeuter M Huisman MV D-dimer testing in patients with suspected pulmonary embolism and impaired renal function.Am J Med. 2009; 122: 1050-1053Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar In addition, recent research has focused on establishing new normal ranges for special populations, including patients who are elderly or pregnant.4Douma RA le Gal G Söhne M et al.Potential of an age adjusted D-dimer cut-off value to improve the exclusion of pulmonary embolism in older patients: a retrospective analysis of three large cohorts.BMJ. 2010; 340: c1475Crossref PubMed Scopus (244) Google Scholar, 5Kovac M Mikovic Z Rakicevic L et al.The use of D-dimer with new cutoff can be useful in diagnosis of venous thromboembolism in pregnancy.Eur J Obstet Gynecol Reprod Biol. 2010; 148: 27-30Abstract Full Text Full Text PDF PubMed Scopus (90) Google Scholar Use of these new cutoff values in treatment studies may increase the diagnostic utility of the D-dimer in these groups in the future. All That Glitters Is Not Gold in Pursuing the Diagnosis of Pulmonary EmbolismCHESTVol. 141Issue 1PreviewWe read with great interest the study by Moores and colleagues1 published in a recent issue of CHEST (August 2011). It gives an up-to-date, balanced overview of the approach to the diagnosis of acute nonmassive pulmonary embolism. Full-Text PDF