Background and Goal of Study: Preoperative anemia is common among older patients
undergoing major noncardiac
surgeries and is associated with increased risk of postoperative
mortality and morbidity[1].To date, studies linking preoperative anemia and perioperative myocardial
injury (PMI) are lacking. This is important as even mild, asymptomatic biochemical elevation of
cardiac enzymes is associated with significantly higher 30day
mortality risk[2]. We aim to
investigate the relationship between preoperative anaemia with 30 day mortality rate and PMI among
older patients who underwent noncardiac
surgery.
Materials and Methods: We retrieved 32910 patients above 65 years old who underwent surgery
between 1 Jan 2012 to 31 Oct 2016 in a tertiary academic medical center. Patients who underwent
cardiac, transplant and neurosurgery, minor procedures not requiring general or regional
anaesthesia, or who had missing data were excluded. Every patient was analyzed once based on
the first surgery performed. 13695 patients were analyzed. Preoperative haemoglobin classified
according to WHO anaemia classification, cardiac, neurological and renal comorbidities, ASA score,
surgical urgency and severity and type of anaesthesia were analyzed. Postoperative outcomes
collected include 30 day mortality and 7day
PMI, defined by an elevation of Troponin T > 30ng/ml
and more than 20% increase from baseline. Univariate and multivariate logistic regression were
done to determine the independent effects of anaemia on outcomes.
Results and Discussion: Moderate/severe anaemia (aOR 2.45, p< 0.001) increased 30day
mortality. Mild anaemia (aOR 1.89, p=0.016) and moderate/severe anaemia (aOR 2.27,
p=0.001)were associated with PMI. Other significant factors associated with both 30day
mortality
and PMI include older age(>=75 years), ASA score 3 or higher, preexisting
ischemic heart disease,
emergency surgeries, surgeries under GA compared to regional anaesthesia and moderate/high
risk surgeries.
Conclusion: Preoperative
moderatesevere
anaemia in the elderly significantly increased the odds
of 30day
inhospital
mortality and perioperative myocardial injury.

The influence of preoperative anemia on 30-day mortality and peri-operative myocardial injury among the older patients undergoing non-cardiac surgery: a retrospective cohort study