LV Changes, CABG Contribute to Higher Mortality Risk From Heart Failure

Having heart failure with reduce ejection fraction (HFrEF) may predispose individuals to a higher risk of death following coronary artery bypass grafting, due to left ventricular (LV) changes that include left ventricular hypertrophy (LVH) and left ventricular enlargement (LVE), according to new study findings published in International Journal of General Medicine.

“The relationship between abnormal LV structure and adverse outcomes has been confirmed in diverse patient groups in previous studies,” the authors wrote. “However, it remains uncertain whether LV structure has predictive implications in HFrEF patients with CABG [coronary artery bypass grafting].”

Coronary artery disease, they added, is responsible for up to 60% of heart failure cases.

The data on their 435 consecutive patients show a mean (SD) age of 59.4 (9.6) years, that all had HFrEF (New York Heart Association class II through IV disease) and underwent CABG between January 2013 and July 2019 at Beijing Anzhen Hospital, Capital Medical University, China. Transthoracic echocardiography evaluated LVH and LVE, finding the conditions in 102 and 95 patients, respectively. The entire study cohort was then classified into these 4 groups:

• –LVH/­–LVE (n = 288; 66.2%)
• +LVH/–LVE (n = 52; 12.0%)
• –LVH/+LVE (n = 45; 10.3%)
• +LVH/+LVE (n = 50; 11.5%)

Overall, there was an independent association found between either LVH or LVE (both P < .001) and post-CABG mortality. However, when combined, the lowest risk was seen among the persons in the –LVH/­–LVE group (odds ratio [OR] 1.000, reference), and the highest risk was seen in the +LVH/+LVE group:

• +LVH/–LVE: odds ratio (OR), 7.525 (95% CI, 1.827-30.679; P = .004)
• –LVH/+LVE: OR, 7.253 (95% CI, 1.950-27.185; P = .003)
• +LVH/+LVE: OR, 9.547 (95% CI, 2.726-34.805; P < .001)

Translated to percentages, the mortality rates were 3.1%, 9.6%, 15.6%, and 16.0%, respectively.

These findings were seen after adjusting for the baseline model comprising age, critical state, stroke, recent myocardial infarction, LV ejection fraction, and intervention for ventricular aneurysm, the authors wrote.

Twenty-nine patients died following CABG: 10 each from low cardiac output and severe infection, 7 from cardiac arrest due to malignant arrhythmia, and 2 from stroke. Of this group, 13 had LVH and 15 had LVE. By themselves, LVH was associated with a mortality risk more than 2.5 times greater vs not having LVH, at 12.7% vs 4.8% (P = .01), and LVE with a mortality risk almost 4 times greater vs not having LVE, at 15.8% vs 4.1% (P < .001).

For this study, death was defined as “any death occurring after a surgical procedure during the hospital stay.”

“Adding LV structural types to the baseline model gained an incremental effect on the predictive value for postoperative mortality (AUC: 0.838 [baseline model] vs 0.901 [baseline model + LV structural types]; P for comparison = .010; category-free net reclassification improvement: 0.764; P < .001; integrated discrimination improvement: 0.061; P = .007),” the authors highlighted.

Categorizing patients by their LV remodeling patterns, they concluded, allows for more detailed risk stratification and provides incremental risk predictability. Because of this, routine clinical practice should incorporate evaluation of LVH and LVE via echocardiography.

References

Yan P, Zhang K, Cao J, Dong R. Left ventricular structure is associated with postoperative death after coronary artery bypass grafting in patients with heart failure with reduced ejection fraction. Int J Gen Med. 2022;15:53-62. doi:10.2147/IJGM.S341145