Preoperative cardiac evaluation: mechanisms, assessment, and reduction of risk

The changing paradigm in cardiovascular disease in which atherosclerotic lesions exist in a spectrum of stable to unstable, the lack of a perfect prediction tool, and the paucity of randomized controlled data on appropriate intervention make protection of cardiac patients undergoing thoracic surgery challenging. Nociception-related sympathetic drive combines with inflammatory stimuli and the cardiodepressant effects of anesthesia to create a window of maximum risk in the early postoperative period (8-24 hours), and although multivariate models have shown that a combination of surgery-specific risk, patient-specific cardiovascular history, and estimated functional capacity best determine the need for further investigation, the optimal choice of investigation is unclear. Exercise or dobutamine stress echocardiography provide the best validated investigations, and in the case of poor images, dobutamine MR imaging is increasingly used. When disease is found, medical and interventional options are available. PCI is often used, but the risk of converting a stable flow-limiting lesion into a less stable non-flow-limiting lesion must be considered, along with a delay for anti-platelet therapy and endothelialization of the stent. Alternatively, medical protection with acute beta-blockade or alpha2-agonists reduces risk (although beta-blockade often is avoided in chronic lung disease, even nonselective agents are safe in patients with non-airways reactive COPD). In addition, it is likely that statin use reduces risk, probably by stabilizing plaques, but patients with cardiac risk are increasingly likely to be taking this medication already. The assessment and management of cardiac risk in the perioperative thoracic surgery patient is challenging. With focused, rational, and individually tailored management; tight monitoring of postoperative pain; and a close working relationship between the surgeon, anesthesiologist, and cardiologist, patient care can be optimized, and risk can be effectively controlled.