Prognostic value of postoperative high-sensitivity troponin T in patients with different stages of kidney disease undergoing noncardiac surgery.

BACKGROUND: Emerging evidence suggests that postoperative troponin release is a strong and independent predictor of short-term mortality. However, evaluating elevated troponins in patients with chronic kidney disease (CKD) is still controversial and is often disregarded. This study examines morbidity along with short- and long-term mortality risk associated with elevated high-sensitivity troponin T (hsTnT) in patients with different stages CKD undergoing noncardiac surgery. METHODS: This observational cohort comprised 3262 patients aged ≥60 yr who underwent noncardiac surgery. Postoperative hsTnT concentrations were divided into normal [<14 ng l-1 (reference)], low (14-49 ng l-1), moderate (50-149 ng l-1), and high (≥150 ng l-1) groups. A threshold of 50 ng l-1 was used to dichotomize hsTnT. The study endpoints were 30-day and long-term all-cause mortality, and postoperative myocardial infarction. RESULTS: Postoperative hsTnT was associated with a stepwise increase in 30-day and long-term mortality risk: low hsTnT adjusted hazard ratio (HR) 1.4 [95% confidence interval (CI): 1.1-1.7], moderate hsTnT adjusted HR 3.1 (95% CI: 2.3-4.3), high hsTnT adjusted HR 5.5 (95% CI: 3.6-8.4). Postoperative hsTnT ≥50 ng l-1 was associated with 30-day and long-term mortality risk for each stage of CKD. Elevated troponin concentrations in severe CKD (estimated glomerular filtration rate <30 mL min-1 1.73 m-2), however, did not predict short-term death. CONCLUSIONS: Elevated postoperative hsTnT is associated with a dose-dependent increase in 30-day and long-term mortality risk in each stage of CKD with an estimated glomerular filtration rate ≥30 ml min-1 1.73 m-2.

Association between postoperative mean arterial blood pressure and myocardial injury after noncardiac surgery.

BACKGROUND: Myocardial injury after noncardiac surgery is common, although the exact pathophysiology is unknown. It is plausible that hypotension after surgery is relevant for the development of myocardial injury. The authors evaluated whether low mean arterial pressures (MAPs) after surgery are related to an increased incidence in postoperative cardiac-troponin elevation. METHODS: A prospective cohort of 2211 patients aged ≥60 yr, undergoing major or moderate noncardiac surgery in The Netherlands, was retrospectively analysed for the occurrence of postoperative cardiac-troponin elevation [high-sensitive troponin T (hsTnT) >14 ng L-1]. Blood pressures after surgery were recorded and divided into quartiles based on the lowest MAP prior to peak troponin recording. The association between MAP and extent of postoperative cardiac-troponin elevation was analysed. RESULTS: The patients were divided into quartiles based on their lowest MAP in the period preceding the peak hsTnT, ranging from a median of 62 in the lowest quartile to 94 in the highest quartile. Postoperative hsTnT elevation was present in 53.2% of the population. An association between MAP quartile and postoperative peak hsTnT was predominantly observed in the lowest quartile (P<0.001): median hsTnT 17.6 (10.3-37.3), 14.9 (9.4-24.6), 13.8 (9.1-22.5), and 14.0 (9.2-22.4). The multivariable logistic-regression analysis showed an increased risk for postoperative cardiac-troponin elevation with decreasing MAP thresholds. CONCLUSIONS: Lower postoperative blood pressure is associated with an increased incidence of postoperative cardiac hsTnT elevation, irrespective of pre- and intraoperative variables.