The association between peri‐operative acute risk change (ARC) and long‐term survival after cardiac surgery

Abstract

Acute risk change has been described as the difference in calculated mortality risk between the pre-operative and postoperative periods of cardiac surgery. We aimed to assess whether this was associated with long-term survival after cardiac surgery. We retrospectively analysed 22,570 cardiac surgical patients, with minimum and maximum follow-up of 1.0 and 6.7 years. Acute risk change was calculated as the arithmetic difference between pre- and postoperative mortality risk. 'Rising risk' represented an increase in risk from pre- to postoperative phase. The primary outcome was one-year mortality. Secondary outcomes included mortality at 3 and 5 years and time to death. Univariable and multivariable analyses were undertaken to examine the relationship between acute risk change and outcomes. Rising risk was associated with higher mortality (5.6% vs. 3.5%, p < 0.001). After adjusting for baseline risk, rising risk was independently associated with increased 1-year mortality (OR 2.6, 95%CI 2.2-3.0, p < 0.001). The association of rising risk with long-term survival was greatest in patients with highest baseline risk. Cox regression confirmed rising risk was associated with shorter time to death (HR 1.86, 1.68-2.05, p < 0.001). Acute risk change may represent peri-operative clinical events in combination with unmeasured patient risk and noise. Measuring risk change could potentially identify patterns of events that may be amenable to investigation and intervention. Further work with case review, and risk scoring with shared variables, may identify mechanisms, including the interaction between miscalibration of risk and true differences in peri-operative care.

Use of Levosimendan in Cardiac Surgery: An Update After the LEVO-CTS, CHEETAH, and LICORN Trials in the Light of Clinical Practice

“… 1 However, in patients with postoperative low cardiac output syndrome (LCOS), mortality is considerably higher. 2 In addition to higher mortality, LCOS predisposes patients to postoperative myocardial injury, renal failure, and prolonged intensive care unit (ICU) and hospital stay. 3 Several baseline factors, such as preoperatively reduced left (and/or right) ventricular function or recent myocardial infarction, predispose patients to LCOS.…”

The significance of risk adjustment for the assessment of results in intensive care. : An analysis of risk adjustment models used in Swedish intensive care.

“…Discrimination of the new model in the validation dataset was good (aROC of 0.86) compared to that described using general intensive care risk adjustment models in cardiac surgical intensive care [33,34]. Using measurements available on arrival to the ICU is potentially interesting to calculate a change in risk from preoperative to postoperative caused by circumstances during surgery [72].…”

Recycling old data – an ethical and pragmatic way to generate new evidence?

“…One possibility is that such tests may be a way to account for the difference between pre‐ and postoperative risk, which Coulson et al. previously termed the ‘acute risk change’ . Although this seems to be associated with postoperative mortality following cardiac surgery, Carlisle challenged this by suggesting their finding was a mathematical consequence of rounding the pre‐operative but not the postoperative risk .…”