Six-Month Outcomes After High-Risk Coronary Artery Bypass Graft Surgery and Preoperative Intra-aortic Balloon Counterpulsation Use: An Inception Cohort Study.

OBJECTIVE

To inform the design of a pivotal randomized controlled trial of prophylactic intra-aortic balloon counterpulsation (IABC) in patients undergoing coronary artery bypass graft (CABG) at high risk of postoperative low cardiac output syndrome (LCOS).

DESIGN

Inception cohort study.

SETTING

A total of 13 established cardiac centers in Australia, Canada, New Zealand, and the United Kingdom.

PARTICIPANTS

Adult patients were eligible for inclusion if they were listed for CABG surgery and had 2 or more LCOS risk factors (low ejection fraction, severe left main coronary artery disease, redo sternotomy, unstable angina).

INTERVENTIONS

Outcomes of interest were a composite outcome of in-hospital mortality, postoperative acute myocardial infarction (AMI), acute kidney injury (AKI), or stroke as well as 6-month vital status and quality of life using the EuroQol 5-dimensional questionnaire (EQ5D).

MEASUREMENTS AND MAIN RESULTS

The study included 136 participants over a 29-month period. Overall, in-hospital and 6-month mortality occurred in 7 (5%) and 11 (8%) participants, respectively. The composite outcome occurred in 60 (44%). The mean increase in EQ5D summary index at 6 months was 0.10 (standard deviation 0.24, p = 0.01). Perioperative AMI, AKI, or stroke significantly decreased the odds of a clinically meaningful improvement in quality of life (odds ratio 0.32; 95% confidence interval 0.13-0.79; p = 0.014). Preoperative IABC was used in 39 participants and did not predict postoperative outcomes.

CONCLUSIONS

The study identified a group of patients at risk of LCOS in whom CABG surgery was associated with a substantial burden of perioperative morbidity. Preoperative IABC use was variable, supporting the need for further research.