
==== Front
Medicine (Baltimore)
Medicine (Baltimore)
MD
Medicine
0025-7974
1536-5964
Lippincott Williams & Wilkins Hagerstown, MD

39029005
MD-D-24-00294
00007
10.1097/MD.0000000000038844
3
3400
Research Article
Observational Study
A comparative study examining the impact of coronary artery bypass grafting surgery with non-extracorporeal circulation on heart function and structure in patients with various forms of coronary heart diseases
Bai Xue-Peng MM xuepengbaibxp@21cn.com
a
Li Jia-Xing MM jiaxinglifam@21cn.com
b
Ma Jin-Lan MM majinlannm9@21cn.com
c
Tian Xin-Bao MM tianxinbaottxn59@21cn.com
d
Han Chao MM hanchaohhn8g@21cn.com
a
https://orcid.org/0009-0005-6905-0043
Wang Yun PhD a*
a Department of Cardiovascular Surgery, General Hospital of Ningxia Medical University, Ningxia, China
b Department of Cardiovascular Medicine, General Hospital of Ningxia Medical University, Ningxia, China
c Department of Intensive Care Unit Medicine, General Hospital of Ningxia Medical University, Ningxia, China
d Department of Rehabilitation Medicine, General Hospital of Ningxia Medical University, Ningxia, China.
* Correspondence: Yun Wang, Department of Cardiovascular Surgery, General Hospital of Ningxia Medical University, No.804 of ShengLi Road, XingQing District, Ningxia 750000, China (e-mail:wangyuncloudy@126.com).
19 7 2024
19 7 2024
103 29 e3884409 1 2024
13 6 2024
14 6 2024
Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial License 4.0 (CCBY-NC), where it is permissible to download, share, remix, transform, and buildup the work provided it is properly cited. The work cannot be used commercially without permission from the journal.

The aim of this study is to assess alterations in heart function and structure in patients diagnosed with non-ST segment elevation acute myocardial infarction (NSTEAMI), unstable angina (UA), and stable angina (SA) 1 year after undergoing off-pump coronary artery bypass grafting (OPCABG) performed without extracorporeal circulation. A total of 182 patients who underwent OPCABG were included and classified into 3 groups based on their preoperative diagnosis: the NSTEAMI group (n = 68), the UA group (n = 64), and the SA group (n = 50). Cardiac ultrasonography data were collected for all groups both preoperatively and 1 year postoperatively. Clinical data were subjected to statistical analysis. In the NSTEAMI group, postoperative observations revealed increases in left ventricular stroke volume and left ventricular end-systolic diameter, along with reductions in left ventricular end-diastolic volume (LVEDV) and left ventricular end-diastolic diameter (LVEDD) 1-year post-surgery. The UA group demonstrated decreases in LVEDV and LVEDD 1-year post-surgery. Similarly, the SA group exhibited an increase in left ventricular ejection fraction (LVEF) and reductions in LVEDV and LVEDD 1-year post-surgery. Comparative analysis of cardiac ultrasonography data revealed that the NSTEAMI group displayed significantly lower left ventricular stroke volume and notably higher left ventricular end-systolic diameter and volume compared to the UA and SA groups 1-year post-surgery. Furthermore, the SA group exhibited significantly elevated LVEF compared to the UA and NSTEAMI groups 1-year post-surgery. Cardiac ultrasonography findings indicate that all 3 groups exhibited improvements in cardiac function and left ventricular structure 1-year post-surgery. However, the NSTEAMI group demonstrated more substantial improvements in comparison to the UA and SA groups.

cardiac ultrasonography
coronary heart disease
off-pump coronary artery bypass grafting (OPCABG) surgery
OPEN-ACCESSTRUE
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pmc1. Introduction

Coronary heart disease (CHD) is a condition characterized by the narrowing or blockage of coronary arteries due to atherosclerosis, leading to reduced blood flow and oxygen supply to the heart muscles, which can result in functional impairment or damage to the heart.[1] CHD is classified into 2 main categories based on etiology and treatment methods: Acute coronary syndrome, which includes acute myocardial infarction and unstable angina, and chronic coronary artery disease, which includes stable angina and asymptomatic myocardial ischemia. Atherosclerosis, the primary cause of CHD, is a complex process involving plaque formation and inflammation in the coronary arteries, driven by various genetic and environmental factors.

Coronary artery bypass grafting (CABG) is a common treatment for patients with ischemic cardiomyopathy.[2] However, these patients often face significant surgical risks and a high chance of complications, and their long-term prognosis depends on the improvement of cardiac function after surgery.[3] Hence, the aim of this study is to assess and compare alterations in heart structure and function in patients diagnosed with non-ST segment elevation acute myocardial infarction (NSTEAMI), unstable angina (UA), and stable angina (SA) following off-pump coronary artery bypass grafting (OPCABG) surgery, without the use of extracorporeal circulation. Our goal is to provide valuable data for the clinical treatment of these 3 types of patients over a 1-year period.

2. Data and methods

2.1. Study participants

This study involved 182 patients with CHD who underwent their initial OPCABG procedure in a single session at the Department of Cardiac Large Vessels Surgery, General Hospital of Ningxia Medical University. The study period spanned from January 2020 to May 2021. Based on the CHD classification criteria, the 182 patients were categorized into 3 groups: non-NSTEAMI (68 patients, accounting for 37.36%), UA (64 patients, accounting for 35.16%), and SA (50 patients, accounting for 37.48%). This study adhered to the principles outlined in the Declaration of Helsinki. Ethical clearance for the study was obtained from the Ethics Committee of General Hospital of Ningxia Medical University (Approval Number: 2020-724). Prior to participation, all individuals provided written informed consent.

2.1.1. Inclusion criteria

Patients who received diagnoses of NSTEAMI, UA, and SA through assessments such as coronary angiography, electrocardiogram readings, changes in myocardial enzymes, and clinical symptoms. Patients with NSTEAMI should have troponin levels upon admission at least threefold higher than their baseline measurements. Patients who had regular postoperative checkups and possessed comprehensive case information, including cardiac ultrasonography findings.

2.1.2. Exclusion criteria

① Patients who underwent additional cardiac surgeries along with OPCABG.

② Patients who received supplementary surgical interventions along with OPCABG throughout the perioperative phase (excluding percutaneous coronary intervention [PCI]).

③ Patients displaying electrocardiographic evidence of ST-segment elevation or the presence of pathological Q waves.

④ Patients who failed to engage in regular post-operative checkups and had incomplete case information, such as inadequate cardiac ultrasonography findings.

2.2. Research methods

The necessary indicators for data collection were identified based on a review of relevant literature and research materials. Baseline data prior to surgery, as well as preoperative and 1-year postoperative cardiac ultrasonography data, were collected. By comparing and analyzing the preoperative and 1-year postoperative cardiac ultrasonography data from the 3 groups, the distinct changes in cardiac function and structure caused by OPCABG were assessed.

2.3. Statistical analysis

Statistical analysis was performed using SPSS 26.0 software, with a significance level set at α = 0.05. Enumeration data are expressed as percentages and case numbers and analyzed using the chi-squared test or Fisher exact test. Measurement data are expressed as mean ± standard deviation. Intra-group comparisons were conducted using pairwise sample t-tests, while inter-group comparisons were carried out using one-way ANOVA (analysis of variance). A statistically significant difference was considered when the value of P was <.05 (P < .05).

3. Results

3.1. Baseline characteristics of the 3 groups before surgery

In this study, a total of 182 patients were examined and categorized into 3 groups: NSTEAMI group (n = 68), UA group (n = 64), and SA group (n = 50). The cohort consisted of 122 males (67.03%) and 60 females (32.97%), aged between 45 and 81 years. The distribution of coronary artery disease types varied among the 3 groups. The NSTEAMI and UA groups predominantly exhibited disorders in the 3 primary blood vessels of the coronary arteries, namely, the right coronary artery, the left anterior descending coronary artery, and the left circumflex coronary artery. Conversely, the SA group mainly exhibited disorders in the left main artery and proximal segment of the anterior descending artery. The NSTEAMI and UA groups had a significantly higher number of patients with arrhythmia, pulmonary disease, or previous myocardial infarction before surgery compared to the SA group. Moreover, the NSTEAMI group had a significantly higher number of patients with a previous cerebral infarction compared to both the UA and SA groups. Additionally, the NSTEAMI and UA groups had a significantly higher number of patients with left ventricular ejection fraction (LVEF) < 40% before surgery compared to the SA group. All these differences were statistically significant with a P < .05 (Table 1).

Table 1 Baseline characteristics of the 3 groups before surgery.

Item	NSTEMI group (n = 68)	UA group (n = 64)	SA group (n = 50)	χ2/F	P	
Age (yr)	65.41 ± 8.67	67.38 ± 6.67	66.44 ± 7.97	1.040	.356	
Male (case number [%])	52 (76.5)	40 (62.5)	30 (60.00)	4.455	.108▲	
Coronary artery disorder (case number [%])	
 Left main artery	39 (57.35)	38 (59.4)	47 (94.00)#,&	29.92	.000▲	
 Proximal segment of the anterior descending artery	28 (41.2)	39 (60.9.00)	48 (96.00)#,&	43.907	.000▲	
 Anterior descending artery	65 (95.6)	64 (100)	50 (100.00)	5.144	.113▲	
 Disorders in the 3 major blood vessels of the coronary arteries	44 (64.7)	56 (87.5)*	11 (22)#,&	51.247	.000▲	
 Disorders in 2 of the 3 major blood vessels of the coronary arteries	23 (33.8)	7 (10.9)*	39 (78.0)&	13.146	.001▲	
Past medical history (case number [%])	
 Hypertension	41 (60.3)	40 (62.5)	22 (44.0)	4.516	.105▲	
 Diabetes mellitus	35 (51.5)	25 (39.1)	15 (30.0)	5.670	.059▲	
 Hyperlipidemia	7 (10.3)	11 (17.2)	9 (18.0)	1.787	.407▲	
 Valvular disease	21 (30.9)	22 (34.4)	19 (38.0)	0.654	.709▲	
 Arrhythmia	9 (13.2)	7 (10.9)	0 (0.0)#,&	8.375	.015▲	
 Lung disease	18 (26.47)	7 (10.94)*	0 (0.0)#,&	17.691	.006▲	
 Cerebral infarction	13 (19.12)	0 (0.00)*	1 (2.00)&	22.304	.000▲	
 Previous myocardial infarction	24 (35.3)	12 (18.8)*	8 (16.00)#	7.437	.024▲	
Preoperative LVEF (%) < 40% (case number [%])	27 (39.71)	23 (35.94)	7 (14.00)#,&	10.685	.005▲	
& indicates the comparison between the UA and SA groups. P < .05 indicates there is a statistically significant difference.

indicates the use of analysis of variance, and

▲ indicates the use of the chi-squared test.

LVEF = left ventricular ejection fraction, NSTEMI = non-ST-segment elevation myocardial infarction, SAP = stable angina pectoris, UA = unstable angina.

* indicates the comparison between the NSTEMI and UA groups.

# indicates the comparison between the NSTEMI and SA groups.

3.2. Cardiac ultrasonography data before surgery and 1 year after surgery for the 3 groups

3.2.1. Cardiac ultrasonography data before surgery and 1 year after surgery

Following surgery, the NSTEAMI group exhibited increases in left ventricular stroke volume and left ventricular end-systolic diameter, alongside decreases in left ventricular end-diastolic volume (LVEDV) and left ventricular end-diastolic diameter (LVEDD) 1-year post-surgery, compared to preoperative measurements. Conversely, the UA group demonstrated reductions in left ventricular stroke volume, LVEDV, and LVEDD 1-year post-surgery relative to their preoperative values. In the SA group, LVEF increased, while LVEDV and LVEDD decreased 1-year post-surgery compared to preoperative measurements. All these differences were statistically significant (P < .05) (Table 2).

Table 2 Intra-group comparisons of cardiac ultrasonography data before and 1 year after surgery in the 3 groups.

Item	Preoperative	Postoperative	t	P	
NSTEMI group (n = 68)	
 LVEF (%)	54.51 ± 11.24	57.18 ± 11.43	−1.767	.082	
 Left ventricular stroke volume (mL)	65.15 ± 10.55	67.64 ± 13.26	3.515	.001	
 Left ventricular end-diastolic volume (mL)	130.45 ± 53.14	114.33 ± 53.57	−2.494	.015	
 Left ventricular end-systolic volume (mL)	75.7 ± 26.4	71.4 ± 36.65	1.008	.317	
 Left ventricular end-diastolic diameter (mm)	58.13 ± 9.95	47.16 ± 10.81	−3.503	.001	
 Left ventricular end-systolic diameter (mm)	42.08 ± 10.79	43.3 ± 11.31	6.188	.000	
UA group (n = 64)	
 LVEF (%)	58.15 ± 12.21	60.61 ± 10.05	−1.488	.142	
 Left ventricular stroke volume (mL)	73.89 ± 14.31	67.66 ± 15.26	2.892	.005	
 Left ventricular end-diastolic volume (mL)	126.66 ± 31.92	112.99 ± 30.19	4.797	.000	
 Left ventricular end-systolic volume (mL)	52.86 ± 27.12	46.22 ± 22.31	2.717	.009	
 Left ventricular end-diastolic diameter (mm)	51.73 ± 7.29	48.77 ± 5.71	3.829	.000	
 Left ventricular end-systolic diameter (mm)	34.08 ± 7.15	33.09 ± 6.92	1.079	.285	
SA group (n = 50)	
 LVEF (%)	63.21 ± 8.4	65.09 ± 7.83	−2.152	.037	
 Left ventricular stroke volume (mL)	72.99 ± 13.78	70.67 ± 16.59	0.993	.326	
 Left ventricular end-diastolic volume (mL)	117.06 ± 26.65	105.85 ± 27.84	3.449	.001	
 Left ventricular end-systolic volume (mL)	43.57 ± 18.25	44.91 ± 21.45	−0.52	.606	
 Left ventricular end-diastolic diameter (mm)	49.75 ± 5.11	47.94 ± 4.68	2.62	.012	
 Left ventricular end-systolic diameter (mm)	33.15 ± 5.83	30.33 ± 5.43	3.874	.000	
P < .05 (marked in bold) indicates there is a statistically significant difference.

LVEF = left ventricular ejection fraction, NSTEMI = non-ST-segment elevation myocardial infarction, SAP = stable angina pectoris, UA = unstable angina.

3.2.2. Cardiac ultrasonography data before surgery and 1 year after surgery for the 3 groups

Preoperative data revealed that the SA group had elevated LVEF and decreased LVEDV compared to both the NSTEAMI and UA groups. Conversely, the NSTEAMI group showed notably higher LVEDV and LVEDD, along with significantly lower left ventricular stroke volume, compared to the UA and SA groups. Postoperative analysis indicated that the NSTEAMI group exhibited notably elevated left ventricular end-systolic volume and left ventricular end-systolic diameter, along with a significant reduction in left ventricular stroke volume compared to both the UA and SA groups. Furthermore, the SA group demonstrated significantly higher LVEF than the UA and NSTEAMI groups. All these differences were statistically significant (P < .05) (Table 3).

Table 3 Inter-group comparisons of cardiac ultrasonography data before and 1 yr after surgery among the 3 groups.

Item	NSTEMI group (n = 68)	UA group (n = 64)	SAP group (n = 50)	F	P	
Preoperative						
LVEF (%)	54.35 ± 11.23	58.4 ± 12.18	63.45 ± 8.32#,&	12.616	.00	
 Left ventricular stroke volume (mL)	60.15 ± 10.55	73.97 ± 14.42*	72.69 ± 13.70#	36.429	.00	
 Left ventricular end-diastolic volume (mL)	130.45 ± 53.14	126.29 ± 31.63*	116.2 ± 26.67#	17.949	.001	
 Left ventricular end-systolic volume (mL)	75.22 ± 26.15	53.49 ± 27.62*	43.03 ± 18.14#,&	30.26	.00	
 Left ventricular end-diastolic diameter (mm)	58.13 ± 9.95	51.81 ± 7.35*	49.58 ± 5.12#	17.628	.00	
 Left ventricular end-systolic diameter (mm)	42.29 ± 10.7	34.33 ± 7.22*	32.94 ± 5.83#	76.12	.00	
Postoperative						
 Left ventricular end-diastolic diameter (mm)	47.27 ± 10.75	48.77 ± 5.71	47.94 ± 4.68	0.626	.54	
 Left ventricular end-systolic diameter (mm)	43.27 ± 11.22	33.09 ± 6.92*	30.33 ± 5.43#	32.242	.00	
LVEF (%)	57.03 ± 11.4	60.61 ± 10.05	65.09 ± 7.83#,&	10.216	.00	
 Left ventricular stroke volume (mL)	62.64 ± 13.26	67.66 ± 15.26*	70.67 ± 16.59#	16.103	.00	
 Left ventricular end-diastolic volume (mL)	114.9 ± 53.34	112.99 ± 30.19	105.85 ± 27.84	1.03	.36	
 Left ventricular end-systolic volume (mL)	71.44 ± 36.36	46.22 ± 22.31*	44.91 ± 21.45#	13.29	.00	
LVEF = left ventricular ejection fraction, NSTEMI = non-ST-segment elevation myocardial infarction, SAP = stable angina pectoris, UA = unstable angina.

* indicates the comparison between the NSTEMI and UA groups.

# indicates the comparison between the NSTEMI and SA groups.

& indicates the comparison between the UA and SA groups. P < .05 (marked in bold) indicates there is a statistically significant difference.

4. Discussion

Currently, CHD ranks highest (47.80%) among cardiac diseases causing death, highlighting the severe impact of cardiovascular diseases and the critical importance of surgical intervention.[4,5] CABG is widely recognized and frequently performed worldwide as a treatment for CHD. Clinical observations have shown that CABG is the most effective and essential approach for managing CHD, both in the short term and long term. There is a global consensus on the standard indications for CABG, which include: left main artery stenosis of 50% or more; disorders in the 3 major coronary arteries (right coronary artery, left anterior descending coronary artery, and left circumflex coronary artery); severe stenosis (≥75%) in the proximal segment of the left anterior descending artery in cases of 2-vessel disease; recurrent angina and myocardial infarction post-PCI; and patients with CHD who also have aneurysms, valve diseases, or other conditions requiring surgical treatment.

All participants in this study underwent CABG surgery due to the poor effectiveness of medication or PCI treatment. Among the 182 patients, a majority presented with disorders in the left main artery, proximal left anterior descending (LAD) artery, or disorders in the 3 major coronary arteries, with some individuals also having diabetes mellitus. In the early stages, patients with CHD are commonly prescribed medication to manage disease progression. However, patients with multiple vessel disease or left ventricular dysfunction often require CABG to enhance myocardial blood flow.[6] According to the 2014 ESC/EACTS guidelines on myocardial revascularization, CABG offers significant prognostic benefits for patients with SA who have left main coronary artery disorders or 2 or more major coronary artery diseases.[7] This is particularly true for patients with SA with severe symptoms, positive exercise tests, impaired left ventricular function, and involvement of the proximal segment of the LAD artery. While studies indicate that a low LVEF increases mortality and morbidity after CABG, CABG remains a viable option for patients with impaired LVEF, resulting in better survival outcomes compared to medication alone.[8]

In this study, the majority of participants exhibited characteristics such as low-level LVEF, left ventricular dysfunction due to severe coronary artery disorders, and a long medical history. Therefore, we conducted an observational study to analyze specific cardiac ultrasound parameters in the 3 groups before and 1 year after OPCABG surgery, tracking alterations in cardiac function and left ventricular structure among these cohorts.

The research findings indicate that all 3 groups exhibited improvements in cardiac function and left ventricular structure 1 year after OPCABG. Notably, the NSTEAMI group demonstrated the most substantial improvement.

Among patients with NSTEAMI, postoperative improvements that exhibited statistically significant results included left ventricular stroke volume, LVEDD, left ventricular end-systolic diameter, and LVEDV. In patients with UA, statistically significant indicators for postoperative improvements were left ventricular stroke volume, LVEDV, left ventricular end-systolic volume, and LVEDD. Conversely, for patients with SA, statistically significant indicators for postoperative improvements were LVEF, LVEDD, and LVEDV. Notably, among all the statistically significant indicators observed in this study, the most significant improvements were observed in LVEF, LVEDV, and LVEDD.

Two main reasons were identified for these improvements. Firstly, the surgery itself played a crucial role. CABG effectively removes the coronary artery obstructions in patients with CHD, facilitating adequate blood supply to the myocardium and contributing to the recovery of heart function. Previous studies have shown that CABG surgery can enhance left ventricular function in patients with CHD.[9,10] Secondly, outpatient medication treatment plays an important role. Outpatient care for patients with CHD emphasizes secondary prevention drugs as well as medications for strengthening the heart, lowering blood pressure, and other necessary treatments. Randomized controlled trials (RCTs), meta-analyses, and observational research reports indicate that sacubitril/valsartan improves cardiac function, reverses left ventricular remodeling, reduces the risk of death and hospitalization, lowers levels of heart failure biomarkers, prevents arrhythmias, and enhances the quality of life of patients.[11] In our study, for patients who had initially low LVEF after surgery and did not recover in a short period, we administered sacubitril/valsartan sodium tablets orally at a routine dosage, and the treatment proved to be effective.

Based on our comparisons, after 1 year of undergoing OPCABG surgery, the NSTEAMI patients demonstrated the most notable advancements in heart function and left ventricular structure among the 3 patient groups. This was notably apparent in 3 pivotal indicators: left ventricular stroke volume, LVEDV, and LVEDD. Based on analysis, we identified 2 factors contributing to this outcome. Firstly, prior to the surgery, NSTEAMI patients experienced left ventricular enlargement and heart failure as a result of myocardial infarction. However, significant improvement was observed following the surgery and administration of medication. Research has identified adverse left ventricular remodeling as a complication of myocardial infarction, characterized by left ventricular dilation, decreased LVEF, thinning of the infarcted myocardium, and thickening of the non-infarcted myocardium.[12] Secondly, this improvement may be attributed to the restoration of hibernating myocardium function caused by prolonged coronary ischemia following blood reperfusion. Studies indicate that hibernating myocardium reduces its function in response to long-term ischemia and hypoxia, aligning with the current level of myocardial blood supply.[12] However, irreversible necrosis has not yet occurred in this stage. When normal blood supply is reinstated, the function of the myocardium can be partially or even completely restored. Myocardial hibernation is experienced by approximately 50% of patients with ischemic heart disease and severe conditions. Currently, surgical treatment is considered the most effective method for addressing myocardial hibernation and improving myocardial ischemia.

In summary, comparing patients with UA and SA to patients with NSTEAMI, it was found that patients with NSTEAMI had the most unfavorable preoperative cardiac ultrasound indicators of heart function, including changes in left ventricular remodeling. However, after undergoing OPCABG, all 3 groups experienced enhancements in left ventricular remodeling and cardiac function. Notably, the patients with NSTEAMI experienced significantly greater improvements compared to the patients with UA and SA.

5. Conclusion

Prior to surgery, patients with NSTEAMI and UA exhibited coronary artery disorders primarily involving 3 major vessels: the right coronary artery, the left anterior descending coronary artery, and the left circumflex coronary artery, with the most common disorder occurring in the anterior descending coronary artery. In contrast, patients with SA primarily exhibited disorders in the left main artery and the anterior descending coronary artery. Preoperative complications were more prevalent in patients with NSTEAMI and UA compared to patients with SA. Furthermore, patients with NSTEAMI exhibited poorer preoperative cardiac function, as assessed through echocardiography, and some patients experienced left ventricular remodeling. One year after surgery, all 3 groups demonstrated improvements in left ventricular remodeling and cardiac function. Notably, patients with NSTEAMI exhibited more significant improvements compared to patients with UA and SA.

Author contributions

Conceptualization: Xue-Peng Bai, Yun Wang.

Data curation: Jia-Xing Li, Jin-Lan Ma, Xin-Bao Tian, Chao Han.

Formal analysis: Jia-Xing Li, Jin-Lan Ma.

Funding acquisition: Yun Wang.

Writing – original draft: Xue-Peng Bai, Jia-Xing Li, Chao Han.

Writing – review & editing: Xue-Peng Bai, Xin-Bao Tian.

Abbreviations:

CHD coronary atherosclerotic heart disease

LAD left anterior descending

LVEDD left ventricular end-diastolic diameter

LVEDV left ventricular end-diastolic volume

LVEF left ventricular ejection fraction

OPCABG off-pump coronary artery bypass grafting

PCI percutaneous coronary intervention

UA unstable angina

This study was supported by a grant from 2021 Key research and development program of Autonomous region in the field of social development (No. 2021BEG02035).

Consent for publication was obtained from every individual whose data are included in this manuscript.

This study was conducted in accordance with the declaration of Helsinki.This study was conducted with approval from the Ethics Committee of General Hospital of Ningxia Medical University (2020-724). A written informed consent was obtained from all participants.

The authors have no conflicts of interest to disclose.

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

How to cite this article: Bai X-P, Li J-X, Ma J-L, Tian X-B, Han C, Wang Y. A comparative study examining the impact of coronary artery bypass grafting surgery with non-extracorporeal circulation on heart function and structure in patients with various forms of coronary heart diseases. Medicine 2024;103:29(e38844).
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