Survival After CABG for HF and Preserved vs. Reduced EF

Study Questions:

What is the survival rate after coronary artery bypass grafting (CABG) in patients with preoperative heart failure (HF) and preserved ejection fraction (pEF) versus reduced ejection fraction (rEF)?

Methods:

This was a Swedish nationwide population-based cohort study that included all patients who underwent primary isolated CABG between January 1, 2001, and December 31, 2013. Data were obtained from the Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies (SWEDEHEART) register, with follow-up for all-cause mortality in March 2014. Information regarding baseline characteristics, all-cause mortality, and readmissions for HF was obtained from national health data registers. Preserved EF was defined as ≥50%. The primary outcome was all-cause mortality. A secondary outcome measure was a combination of all-cause mortality and readmission for HF.

Results:

The study included 41,906 patients, 37,234 without known HF (27,165 with pEF and 10,069 with rEF) and 4,672 with HF (1,216 with pEF and 3,456 with rEF). Their mean standard deviation (SD) age was 67.4 (9.3) years, and 21.0% were female. During a mean (SD) follow-up time of 6.0 (3.3) years, 19.0% (7,943 of 41,906) of patients died, including 13.2% (3,574 of 27,165) with no HF and pEF, 24.6% (2,476 of 10,069) with no HF and rEF, 33.9% (412 of 1,216) with HFpEF, and 42.9% (1,481 of 3,456) with HFrEF. The multivariable-adjusted hazard ratios for death were 1.47 (95% confidence interval [CI], 1.40-1.56), 1.62 (95% CI, 1.46-1.80), and 2.29 (95% CI, 2.14-2.44) in patients with no HF and rEF, patients with HFpEF, and patients with HFrEF compared with patients with no HF and pEF. The findings were similar for the combined outcome of all-cause mortality and readmission for HF. The multivariable-adjusted hazard ratios for death within 30 days of surgery were 2.25 (95% CI, 1.86-2.73), 1.83 (95% CI, 1.26-2.66), and 2.52 (95% CI, 1.99-3.19) in patients with no HF and rEF, patients with HFpEF, and patients with HFrEF.

Conclusions:

The authors concluded that a history of HF was an important risk factor for poor short- and long-term outcomes after CABG regardless of preoperative EF.

Perspective:

This study reports that a history of HF was an important independent risk factor for poor short- and long-term outcomes after CABG regardless of preoperative EF. It appears that the HF syndrome itself may be a stronger predictor of long-term outcomes than EF and should be carefully considered in preoperative assessment and postoperative follow-up. Referring cardiologists and cardiac surgeons should be aware that a history of HF is an additional, independent, and important risk factor for early death that the currently used risk models may not take into consideration.

Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Cardiac Surgery and Heart Failure, Acute Heart Failure

Keywords: Cardiac Surgical Procedures, Coronary Artery Bypass, Heart Failure, Mortality, Outcome Assessment (Health Care), Patient Readmission, Risk Factors, Stroke Volume, Survival Rate


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