Letter by Madias Regarding Article, “Perioperative Myocardial Injury After Noncardiac Surgery: Incidence, Mortality, and Characterization”
Authors: John E. Madias
Journal: Circulation (2018)

The article by Puelacher et al 1 focuses on the incidence, characterization, and mortality of a very troubling set of patients, mostly asymptomatic, with perioperative myocardial injury (PMI) after noncardiac surgery (NCS).The authors studied prospectively a consecutive cohort of 2018 patients (median age of 74 years, 42% women) at increased cardiovascular risk, who underwent NCS, and found in 397 (16%) of them elevated (≥14 ng/L) absolute high-sensitivity cardiac troponin T, in comparison with their baseline levels obtained before the NCS. 1 It is notable that patients with PMI had a higher crude 30-day and 1-year mortalities (8.9% and 22.5%, respectively), in comparison with the corresponding mortalities (1.5% and 9.3%) of the 1621 patients without PMI.Importantly, the 30-day mortality of patients with PMI was similar between the 280 (71%) patients without any other of the additional criteria required for the diagnosis of spontaneous acute myocardial infarction (type 2), and the 117 (29%) patients with ≥1 additional criteria for such a diagnosis (10.4% versus 8.7%), respectively. 1This disconcerting finding of patients experiencing elevated high-sensitivity cardiac troponin T after NCS calls for a concerted effort among clinicians and investigators to evaluate the underpinning pathophysiologic intricacies of this syndrome, devise screening methods to prevent PMI, and manage patients with PMI, which also occurs in patients with no cardiovascular risk, undergoing preoperative evaluation, for NCS. 2 The editorialists 2 appropriately remarked on a potential Pandora's box having been opened, pertaining to the pathophysiologic mechanism(s) of the PMI syndrome, its prediction, prevention, and therapy, and the exact role of serial high-sensitivity cardiac troponin T testing.In addition to a possible underlying coronary and general arterial vascular subclinical pathology being present in many patients, particularly elderly, and even when they are asymptomatic before and after NCS, 2 one should consider the pathophysiological upheaval such patients are exposed to, related to preoperative anxiety, the effects and adverse outcomes of anesthesia, surgical injury, blood volume shifts, heightened inflammation, and major dysregulation of autoimmune and autonomic nervous systems.Accordingly, all the above could conspire to exert a harmful effect on the cardiomyocytes or total body, considering that we are not sure yet whether elevated high-sensitivity cardiac troponin T imply PMI, injury to other body tissues or organs, or both. 2 Indeed the inciting scenario leading to PMI after NCS and takotsubo syndrome appears to have many commonalities, and the shortand long-term outcomes appear to be similar. 3Vast literature reveals that the autonomic sympathetic nervous system is hyperactivated in the perioperative setting, as it is in takotsubo syndrome, and one wonders whether in the former, as in the latter, important pathognomonic insights may be forthcoming by checking blood catecholamines and monitoring the thoracic skin nerve activity (a surrogate of stellate ganglia autonomic sympathetic nervous system input to the heart), using the routine elec-