Changes in Right Ventricular Function After Off-Pump Coronary Artery Bypass Grafting

The Outcomes of Coronary Artery Bypass Surgery after 18 Months-Is There an Influence of the Initial Right Ventricle Diastolic Dysfunction?

BACKGROUND

This study aimed to investigate the association of preoperative right heart filling indicators with outcomes after coronary artery bypass grafting (CABG) at an 18 month follow up.

METHODS

Patients who underwent CABG at a single center were included in this study. In addition to the baseline preoperative indicators and perioperative data, initial parameters of the right ventricle (RV) systolic and diastolic function were assessed.

RESULTS

Among the 189 patients, a total of 19 (10.0%) MACE (cardiovascular death, nonfatal myocardial infarction and stroke) were recorded during an 18 month follow up. In patients with the development of MACE during the initial examination, the following changes in RV function were revealed compared with the group without MACE: a decrease in the e't index (8.2 versus 9.6 cm/s, p = 0.029), an increase in the Et/e't ratio (5.25 vs. 4.42, p = 0.049) and more frequent presence of RV pseudonormal filling (p = 0.03). In the binary logistic regression analysis, the development of MACE 18 months after CABG was associated with the nonconduction of PCI before surgery, the presence of peripheral atherosclerosis, an increase in IVST and Et/e't and a decrease in LVEF.

CONCLUSIONS

RV diastolic dysfunction in the preoperative period was associated with the development of MACE within 18 months after CABG, and the ratio Et/e't was one of the independent predictors of MACE in a multiple regression analysis. This makes it expedient to include an assessment of not only systolic but also diastolic RV function in the preoperative examination. The inclusion of an assessment of RV diastolic function in the pre-CABG evaluation of patients deserves further study.

Indicators of the Right Ventricle Systolic and Diastolic Function 18 Months after Coronary Bypass Surgery

Objective. Right ventricular (RV) dysfunction after coronary artery bypass grafting (CABG) is associated with increased mortality and morbidity. In previous studies, the parameters of RV systolic function were mainly assessed, while the dynamics of RV diastolic function after surgery was practically not studied. The aim of this study was to study the dynamics of indicators of systolic and diastolic RV function after CABG as well as to identify factors associated with their presence. Methods. The study included 160 patients who underwent CABG and 36 volunteers with no history of coronary artery disease (CAD) as a control group. Echocardiographic examination of patients was performed to assess systolic and diastolic RV dysfunction before surgery and 18 months after CABG. A level of s’t < 10 cm/sec or TAPSE < 16 mm was considered as a sign of existing RV systolic dysfunction. RV diastolic dysfunction was defined as an Et/At ratio < 0.8 or >2.1 and/or an Et/et’ ratio > 6. Results. In CAD patients 18 months after CABG, there was an increase in the frequency of the right ventricular systolic (from 7.5% to 30%, p < 0.001) and diastolic (from 41.8% to 57.5%, p < 0.001) dysfunction. An increase in TAPSE (p = 0.007), a decrease in e’t (p = 0.005), and the presence of RV systolic dysfunction before surgery (p = 0.023) was associated with a significant increase in the likelihood of detecting RV systolic dysfunction 18 months after CABG (χ2(3) = 17.4, p = 0.001). High values of At before surgery (p = 0.021) and old myocardial infarction (p = 0.023) were significantly associated with an increased likelihood of detection of RV diastolic dysfunction 18 months after CABG (χ2(2) = 10.78, p = 0.005). Conclusions. This study demonstrated that in CAD patients 18 months after CABG, there was an increase in the frequency of right ventricular systolic and diastolic dysfunction. We also established the initial clinical, echocardiographic parameters, and perioperative complications associated with the presence of these changes in the postoperative period. The clinical and prognostic significance of the presence of systolic and/or diastolic RV dysfunction in patients 18 months after CABG remains to be explored.