invited commentary

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in only 10 patients, 4 of whom had PCR-positive findings.

© 2012 by The Society of Thoracic SurgeonsPublished by Elsevier Inc

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INVITED COMMENTARY

The article by D’Journo and colleagues [1] is a prospec-tive study about the molecular detection of microorgan-isms in distal airways of patients undergoing major lungresection for lung cancer. The samples were taken fromthe resected specimen through guided bronchoalveolarlavage (BAL) or tissue biopsy. Microbiologic analysis wasundertaken through a standardized protocol of DNA andRNA extraction for polymerase chain reaction (PCR)sequencing and amplification.

Among the 87 consecutive patients included in thestudy, 13 (15%) had a PCR-positive test for cytomegalo-virus (CMV). No tests resulted positive for encapsulatedbacteria. A higher frequency of respiratory complicationsdeveloped in these positive patients compared with neg-ative patients. In particular, their rate of postoperativepneumonia was as high as 31% vs 8% in the negativepatients. PCR positivity remained an independent signif-icant factor associated with postoperative respiratorycomplications after multivariable analysis.

The authors concluded that a culture-independentmolecular evaluation can be a reliable biologic markerfor early detection of patients at high risk for pulmonarycomplications. The possibility to detect patients at risk forpostoperative respiratory events at the time of theiroperation by using a relatively inexpensive test withsufficient sensitivity and specificity appears intriguing.

The analysis, however, has some limitations. Thus, theresults need to be interpreted with caution, and nodefinitive conclusion should be inferred by this work. Ashonestly admitted by the authors, the sample size wasrelatively small. Even worse, the number of events wassmall—only 27 pulmonary complications—making thefinal multivariable model (including the three predictors)likely overfitted.

The inclusion of sputum retention and atelectasis inthe list of respiratory complications is questionable. Infact, the link between CMV colonization and atelectasisappears far-fetched. The data on pneumonia are cer-tainly more logical; however, this complication occurred

Of the 13 PCR-positive patients, pneumonia occurred in3, and only 1 of them had postoperative polymicrobialbronchoscopic samples that were positive. The associa-tion between PCR-CMV positivity and postoperativepulmonary infection therefore remains still unclear.

To complicate further the matter, no concomitant sam-ple was taken from the larger airways at the time of theoperation. It would have been interesting to know if therewas an association between distal lung viral infection andproximal airway bacterial infection. Nevertheless, theconcept of latent viral infection activation due to animmunosuppressive effect of the operation or cancerstatus leading to postoperative pulmonary dysfunctionand secondary pneumonia is provocative and warrantsfurther investigation.

Among the open questions are: What is the clinicalimplication of this analysis? How should we manage thePCR-CMV–positive patients? Should we individualizetheir antimicrobial prophylaxis? If so, which drugsshould be used if the results of most of the postoperativebronchoscopic samples were negative? Should we thenuse antiviral agents?

The authors must be commended for their vision andfor their inspiring contribution. Hopefully, they will ex-pand and refine their analysis to clarify the outstandingissues of this important contribution.

Alessandro Brunelli, MD

Division of Thoracic SurgeryOspedali Riuniti AnconaVia Conca 160020 Ancona, Italye-mail: brunellialex@gmail.com

Reference

1. D’Journo XB, Bittar F, Trousse D, et al. Molecular detection ofmicroorganisms in distal airways of patients undergoing lung

0003-4975/$36.00doi:10.1016/j.athoracsur.2011.10.008