External validation of the recalibrated thoracic revised cardiac risk index for predicting the risk of major cardiac complications after lung resection

Background: The recalibrated thoracic revised cardiac risk index (ThRCRI) has been recently proposed as a specific tool for cardiac risk stratification before lung resection. However, the ThRCRI has never been externally validated in a population other than the one from which it was derived. The objective of this study was to validate the ThRCRI in an external population of candidates having undergone major lung resections to assess its reliability for cardiac risk stratification across different samples. Methods: We analyzed 2,621 patients undergoing lobectomy (2,431) or pneumonectomy (190) in a single center from 2000 to 2009. Patients were grouped into four classes of risk (A, B, C, and D) according to the recalibrated ThRCRI. The outcome variable measured was the occurrence of major cardiac complications (cardiac arrest, complete heart block, acute myocardial infarction, pulmonary edema, cardiac death during admission). Incidence of major cardiac events was assessed in the four risk class groupings to assess the discriminative ability of the index score. Results: The incidence of major cardiac morbidity was 2.2% (59 cases). Patients were grouped into four risk classes according to their recalibrated ThRCRI. Incidence of major cardiac morbidity in risk classes A, B, C, and D were 0.9%, 4.2%, 8%, and 18%, respectively (p < 0.0001). Conclusions: The recalibrated ThRCRI is a reliable instrument that can be used during preoperative workup to differentiate patients needing further cardiologic testing from those who can proceed without any further cardiac testing.