Size-capacity mismatch in the lung: a novel predictor for complications after lung cancer surgery.

BACKGROUND: The aim of the present study was to make a combined pulmonary functional and anatomical assessment using spirometry and computed tomography (CT) to clarify the best predictor for cardiopulmonary complications after thoracoscopic major lung resection for cancer. METHODS: We retrospectively reviewed our prospective database of 304 patients undergoing thoracoscopic major lung resection for cancer. The total lung volume (TLV) was measured preoperatively using deep-inspiratory CT by summing the voxels representing -600 to -1024 Hounsfield units. Forced vital capacity (FVC) was measured by spirometry. FVC/TLV was used to diagnose a lung size-function mismatch. We compared among FVC/TLV, conventional spirometric parameters, and the risk of postoperative cardiopulmonary complications. RESULTS: Postoperative cardiopulmonary complications developed in 25 of 304 patients (8.2%). There were no cases of operative mortality. A stepwise logistic regression analysis revealed that a history of smoking and low FVC/TLV were independent risk factors for postoperative cardiopulmonary complications in various preoperative measurements. According to a receiver-operating characteristic analysis, FVC/TLV was the only variable that was statistically useful for predicting complications (area under the receiver-operating characteristic curve > 0.7). CONCLUSIONS: Lung size-function mismatch was identified as the best predictor for cardiopulmonary complications after major lung resection for cancer among various spirometry- and CT-derived parameters. The usefulness of this parameter in screening for patients who are at risk of complications should be validated by a multicenter, large-scale study because it can be obtained through routine preoperative work.