Effect of quantitative parameters of contrast-enhanced ultrasound on the long-term prognosis of patients with chronic coronary syndrome
Original Article

Effect of quantitative parameters of contrast-enhanced ultrasound on the long-term prognosis of patients with chronic coronary syndrome

Jia Li1#, Chunyan Ma2#, Haixia Sun1, Fang Li1, Yao She3, Tianhong Yi3

1Cardiovascular Ultrasound Room, Qinghai Provincial People’s Hospital, Xining, China; 2Department of Ultrasound, Central South University Xiangya School of Medicine Affiliated Haikou Hospital, Haikou, China; 3Department of Ultrasound, Yueyang People’s Hospital, Yueyang, China

Contributions: (I) Conception and design: J Li, C Ma; (II) Administrative support: T Yi; (III) Provision of study materials or patients: All authors; (IV) Collection and assembly of data: All authors; (V) Data analysis and interpretation: All authors; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors.

#These authors contributed equally to this work.

Correspondence to: Tianhong Yi, MD. Department of Ultrasound, Yueyang People’s Hospital, 263, Baling East Road, Yueyanglou District, Yueyang 414000, China. Email: yitianhong2023@sina.com.

Background: Ultrasound is one of the most commonly used examination methods in patients with coronary artery disease (CAD) and is valuable in evaluating patient prognosis. Although contrast-enhanced ultrasound (CEUS) can assess more in depth the vascular lesions of patients, there is still a lack of relevant research on the value of quantitative parameters of CEUS in predicting the long-term prognosis of patients with chronic coronary syndrome (CCS), thus, we designed this study.

Methods: From January 2016 to December 2017, a total of 473 patients with CCS admitted to Yueyang People’s Hospital were retrospectively enrolled. The patients were followed up for five years. According to whether the patients had major adverse cardiovascular events (MACE), patients were divided into the MACE group (n=113) and the control group (n=360). The CEUS was performed to detect the myocardial perfusion status. The value of quantitative parameters of CEUS in predicting the MACE in patients with CCS was analyzed using the receiver operating characteristic (ROC) curve.

Results: Peak intensity of contrast agent at platform stage, rising rate of microbubble reperfusion, and left ventricular ejection fraction (LVEF) were found to be valuable in predicting the risk of MACE in patients with CCS. Among them, the peak intensity of contrast agent at platform stage had the highest predictive value, and the area under the curve (AUC) was 0.860 [95% confidence interval (CI): 0.827–0.894, P<0.001]. Multivariate logistics regression analysis showed that the peak intensity of contrast agent at platform stage <4.54 dB and rising rate of microbubble reperfusion <0.275 s were independent risk factors of MACE in patients with CCS. The relative risks were 12.238 (95% CI: 6.632–22.585) and 5.724 (95% CI: 3.149–10.405), respectively.

Conclusions: Quantitative parameters of CEUS can be used as predictors of MACE in patients with CCS, and strengthening the management of such high-risk patients may be beneficial to reduce the incidence of MACE.

Keywords: Contrast-enhanced ultrasound (CEUS); chronic coronary syndrome (CCS); major adverse cardiovascular events (MACE)

Submitted Aug 13, 2023. Accepted for publication Nov 16, 2023. Published online Dec 10, 2023.

doi: 10.21037/jtd-23-1267

Highlight box

Key findings

• The quantitative parameters of contrast-enhanced ultrasound (CEUS) can be used as predictors of major adverse cardiovascular events (MACE) in patients with chronic coronary syndrome.

What is known and what is new?

• At present, there is a lack of research on the value of quantitative parameters of CEUS in predicting the long-term prognosis of patients with chronic coronary syndrome.

• Peak intensity of contrast agent at platform stage <4.54 dB and rising rate of microbubble reperfusion <0.275 s were found to be independent risk factors of MACE in patients with chronic coronary syndrome.

What is the implication, and what should change now?

• Quantitative parameters of CEUS can be used as predictors of MACE in patients with chronic coronary syndrome, and strengthening the management of such high-risk patients may be beneficial to reduce the incidence of MACE.

Introduction

In recent years, with the change of diet and living habits, the incidences of arterial hypertension, diabetes, and hyperlipidemia have increased year by year, the incidence of coronary artery disease (CAD) has subsequently increased year by year, which is one of the main risk factors for death in middle-aged and elderly people (1-4). Chronic coronary syndrome (CCS) refers to the absence of major adverse cardiovascular events (MACE) such as myocardial infarction on the basis of severe stenosis of the coronary arteries. When the myocardial loading is increased due to exercise, transient myocardial ischemia and hypoxia symptoms can occur, manifested as transient angina. In addition, patients with CCS can experience MACE such as myocardial infarction, malignant arrhythmia, heart failure, and cardiac arrest. MACE is a major contributor to death in patients with CCS (5). Therefore, it is important to identify patients at a high risk of MACE. Coronary angiography has high value in predicting prognosis of patients with CCS, but it is invasive and difficult to measure dynamically (6-8). Ultrasound examination is non-invasive. However, in the early stage of CCS, due to the compensatory effect of the myocardium, left ventricular ejection fraction (LVEF) may not be significantly reduced. Contrast-enhanced ultrasound (CEUS), which has emerged in recent years, can assess the severity of myocardial ischemia (9,10). Therefore, we speculated that the quantitative parameters of CEUS can better assess the long-term prognosis of patients with CCS. Due to the lack of relevant studies, we designed this study. We present this article in accordance with the STARD reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1267/rc).

Methods

General information

From January 2016 to December 2017, a total of 473 patients with CCS admitted to Yueyang People’s Hospital were continuously and retrospectively enrolled and followed up for five years. According to whether the patients developed MACE or not, the patients were divided into the MACE group (n=113) and the control group (n=360). The inclusion criteria were as follows: (I) CCS (coronary diameter stenosis degree >50%, no MACE such as myocardial infarction in the past three months, but with the increase of myocardial loading due to exercise, occurrence of transient myocardial ischemia and hypoxia symptoms manifested as transient angina); (II) age ≥18 years; (III) complete clinical data. The exclusion criteria were as follows: (I) malignant tumor; (II) combined with other heart diseases such as congenital heart disease; (III) functional insufficiency of important organs such as the liver and kidneys; (IV) loss to follow-up. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). This retrospective clinical study was approved by the Yueyang People’s Hospital Ethics Committee (No. 20220072), and individual consent for this retrospective analysis was waived. The flowchart of the inclusion process is shown in Figure 1.

Figure 1 Patients’ inclusion flowchart. MACE, major adverse cardiovascular events.

Inspection method

The ultrasounds were performed using a Philips IE33 Elite ultrasound diagnostic instrument (Philips Healthcare, Andover, MA, USA), with a X5-1 matrix probe (1.0–5.0 MHz); the contrast agent used was sulfur hexafluoride microbubbles (Brocoo Company, Italy, 59 mg). The real-time myocardial ultrasound imaging model was equipped. The second harmonic and pulse coding phase reversal harmonic imaging technology were used. The mechanical index was 0.08. We measured peak intensity of contrast agent at platform stage (reflecting myocardial blood volume) and rising rate of microbubble reperfusion (reflecting the average myocardial blood flow velocity). At the same time, routine ultrasound was performed to measure the LVEF. No intolerance nor allergic reactions occurred during the study period.

Data collection

(I) General information: age, gender, body mass index, arterial hypertension, diabetes, hyperlipidemia and medications taken; (II) ultrasound-related parameters: peak intensity of contrast agent at platform stage, rising rate of microbubble reperfusion, LVEF; (III) biochemical indexes: N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high sensitivity c reactive protein; (IV) coronary artery stenosis: the number of coronary artery stenosis and the average degree of coronary stenosis.

Statistical analysis

The software SPSS 26.0 (IBM Corp., Armonk, NY, USA) was used to complete the data analysis, and a two-tailed P<0.05 indicated that the difference was statistically significant. The measurement data of the two groups were expressed by mean ± standard deviation, and the independent sample t-test was used to analyze the differences in the measurement data between the two groups. The counting data of the two groups were expressed by n (%), and the Chi-squared test was used to analyze the difference in the counting data between the two groups. The receiver operating characteristic (ROC) curve was used to analyze the value of ultrasound related parameters in predicting the occurrence of MACE in patients with CCS. Multivariate logistics regression analysis was used to explore the risk factors of MACE in patients with CCS.

Results

Comparison of clinical features of the two groups

There were statistical differences in the peak intensity of contrast agent at platform stage, rising rate of microbubble reperfusion, the LVEF, the number of coronary artery stenosis, and the average degree of coronary stenosis between the two groups (P<0.05) (Table 1).

Table 1

Comparison of clinical features of the two groups

Variable MACE group (n=113) Control group (n=360) t/χ2 value P value
Age (years), mean ± SD 61.50±11.77 61.49±12.04 0.005 0.996
Gender, n (%) 0.247 0.619
   Male 72 (63.72) 220 (61.11)
   Female 41 (36.28) 140 (38.89)
Body mass index (kg/m2), mean ± SD 26.36±3.25 26.27±3.03 0.281 0.779
Arterial hypertension, n (%) 82 (72.57) 250 (69.44) 0.401 0.527
Diabetes, n (%) 45 (39.82) 122 (33.89) 1.326 0.250
Hyperlipidemia, n (%) 100 (88.50) 300 (83.33) 1.756 0.185
Antihypertensive drugs, n (%) 82 (72.57) 250 (69.44) 0.401 0.527
Hypoglycemic drugs, n (%) 45 (39.82) 122 (33.89) 1.326 0.250
Lipid lowering drugs, n (%) 100 (88.50) 300 (83.33) 1.756 0.185
Aspirin, n (%) 108 (95.58) 330 (91.67) 1.917 0.166
Peak intensity of contrast agent at platform stage (dB), mean ± SD 4.04±0.50 5.04±0.71 13.959 <0.001
Rising rate of microbubble reperfusion (s), mean ± SD 0.24±0.03 0.29±0.04 12.275 <0.001
Left ventricular ejection fraction (%), mean ± SD 49.69±6.17 52.59±6.41 4.236 <0.001
NT-proBNP (pg/mL), mean ± SD 413.65±166.51 387.93±190.66 1.288 0.198
High sensitivity C reactive protein (mg/L), mean ± SD 3.04±0.67 2.98±0.62 0.880 0.379
Number of coronary artery stenosis, n (%) 21.982 <0.001
   Single 39 (34.51) 215 (59.72)
   Multiple 74 (65.49) 145 (40.28)
Average degree of coronary stenosis, mean ± SD 81.19±10.18 72.18±10.60 7.956 <0.001

MACE, major adverse cardiovascular events; SD, standard error; NT-proBNP, N-terminal pro-B-type natriuretic peptide.

The value of average degree of coronary stenosis in predicting MACE in patients with CCS

The average degree of coronary stenosis was shown to be valuable in predicting MACE in patients with CCS, and the area under the curve (AUC) was 0.693 [95% confidence interval (CI): 0.636–0.750, P<0.001], the optimal diagnostic cut-off was 77.50%, and the sensitivity and specificity were 0.681 and 0.603, respectively (Figure 2).

Figure 2 Predictive value of mean coronary stenosis for MACE in patients with chronic coronary syndrome. MACE, major adverse cardiovascular events.

The value of peak intensity of contrast agent at platform stage, rising rate of microbubble reperfusion, and LVEF in predicting MACE in patients with CCS

The peak intensity of contrast agent at platform stage, rising rate of microbubble reperfusion, and LVEF were found to be valuable in predicting the absence of MACE in patients with CCS. Among them, the peak intensity of contrast agent at platform stage had the highest predictive value, and the AUC was 0.860 (95% CI: 0.827–0.894, P<0.001) (Figure 3 and Table 2).

Figure 3 The predictive value of different indicators in the absence of MACE in patients with chronic coronary syndrome. MACE, major adverse cardiovascular events.

Table 2

The value of different indicators in predicting the absence of MACE in patients with chronic coronary syndrome

Variables Area (95% CI) Standard error P value Optimal diagnostic threshold Sensitiveness Specificity
Peak intensity of contrast agent at platform stage (dB) 0.860 (0.827–0.894) 0.017 <0.001 4.54 dB 0.708 0.832
Rising rate of microbubble reperfusion (s) 0.815 (0.774–0.855) 0.021 <0.001 0.275 s 0.614 0.805
Left ventricular ejection fraction (%) 0.626 (0.567–0.684) 0.030 <0.001 49.50% 0.644 0.531

MACE, major adverse cardiovascular events; CI, confidence interval.

Risk factor of MACE in patients with CCS

Multivariate logistics regression analysis showed that the peak intensity of contrast agent at platform stage <4.54 dB and rising rate of microbubble reperfusion <0.275 s were independent risk factors of MACE in patients with CCS. The relative risks were 12.238 (95% CI: 6.632–22.585) and 5.724 (95% CI: 3.149–10.405), respectively (Table 3).

Table 3

Risk factors of MACE in patients with chronic coronary syndrome

Variables B value Standard error Wald value P value Relative risk (95% CI)
Peak intensity of contrast agent at platform stage <4.54 dB 2.505 0.313 64.193 <0.001 12.238 (6.632–22.585)
Rising rate of microbubble reperfusion <0.275 s 1.745 0.305 32.743 <0.001 5.724 (3.149–10.405)
Left ventricular ejection fraction <49.5% 0.736 0.284 6.733 0.009 2.087 (1.197–3.639)
Multiple coronary artery stenosis 1.054 0.288 13.439 <0.001 2.870 (1.633–5.044)
Average degree of coronary stenosis >81.50% 1.155 0.286 16.314 <0.001 3.174 (1.812–5.559)
Constant −9.222 1.041 78.513 <0.001 0.000

MACE, major adverse cardiovascular events; CI, confidence interval.

Discussion

The basis of lesions in patients with CAD is coronary atherosclerosis, which leads to coronary stenosis, which in turn leads to insufficient blood supply to the myocardium. Long-term chronic myocardial ischemia can also lead to myocardial remodeling that progresses to MACE (11). In patients with CCS, there may be no significant change or only with a mild decrease in LVEF at early stage due to myocardial compensation (12-14). The present study also showed that LVEF was poor in predicting the MACE. However, in the early stages of CCS, patients exhibit changes in myocardial microvascular perfusion (15-17). Researchers have evaluated microvascular perfusion using CEUS (18,19), and this study explored the relationship between quantitative parameters of myocardial CEUS and the occurrence of MACE in patients with CCS. In the present study, the peak intensity of contrast agent at platform stage and rising rate of microbubble reperfusion were measured by myocardial CEUS. The peak intensity of contrast agent at platform stage represents myocardial blood volume; a rising rate of microbubble reperfusion reflects the average blood flow velocity of the myocardium. The decrease in the peak intensity of contrast agent at platform stage and rising rate of microbubble reperfusion indicate that myocardial hypoxia and ischemia are severe, and MACE is more likely to occur (18). CEUS has become a very important and promising development direction for ultrasound diagnosis (20,21). CEUS is the observation of coronary arteries, heart valves, and other conditions under ultrasound based on the distribution of contrast agents. CEUS is valuable in checking the tumors arterial stenosis and thrombosis.

In the present study, special ultrasound imaging techniques were used to observe the microvascular perfusion of myocardium, which could sensitively reflect the microperfusion of myocardium and provide a better way to identify CCS patients with high-risk of MACE.

The limitation of this study includes it retrospective nature and its failure to dynamically monitor the quantitative parameters of CEUS. Additionally, we failed to study more prognostic factors in this retrospective study.

Conclusions

Predicting the prognosis of different diseases is currently a hot topic and focus of research (22-25). Quantitative parameters of CEUS can be used as predictors of MACE in patients with CCS, and strengthening the management of such high-risk patients may be beneficial to reduce the incidence of MACE.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the STARD reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1267/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1267/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1267/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1267/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). This retrospective clinical study was approved by the Yueyang People’s Hospital Ethics Committee (No. 20220072), and individual consent for this retrospective analysis was waived.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

  1. Eilat-Adar S, Hellerstein D, Goldbourt U. Religiosity Is Associated with Reduced Risk of All-Cause and Coronary Heart Disease Mortality among Jewish Men. Int J Environ Res Public Health 2022;19:12607. [Crossref] [PubMed]
  2. Manresa-Rocamora A, Sarabia JM, Guillen-Garcia S, et al. Heart Rate Variability-Guided Training for Improving Mortality Predictors in Patients with Coronary Artery Disease. Int J Environ Res Public Health 2022;19:10463. [Crossref] [PubMed]
  3. Mooney RE, Linden GJ, Winning L, et al. Association of TGFB1 rs1800469 and BCMO1 rs6564851 with coronary heart disease and IL1B rs16944 with all-cause mortality in men from the Northern Ireland PRIME study. PLoS One 2022;17:e0273333. [Crossref] [PubMed]
  4. Koshy AN, Dinh DT, Fulcher J, et al. Long-term mortality in asymptomatic patients with stable ischemic heart disease undergoing percutaneous coronary intervention. Am Heart J 2022;244:77-85. [Crossref] [PubMed]
  5. Stewart RA, Wallentin L, Benatar J, et al. Dietary patterns and the risk of major adverse cardiovascular events in a global study of high-risk patients with stable coronary heart disease. Eur Heart J 2016;37:1993-2001. [Crossref] [PubMed]
  6. Patel VI, Roy SK, Budoff MJ. Coronary Computed Tomography Angiography (CCTA) vs Functional Imaging in the Evaluation of Stable Ischemic Heart Disease. J Invasive Cardiol 2021;33:E349-54.
  7. Patel MR, Calhoon JH, Dehmer GJ, et al. ACC/AATS/AHA/ASE/ASNC/SCAI/SCCT/STS 2017 appropriate use criteria for coronary revascularization in patients with stable ischemic heart disease: A report of the American College of Cardiology Appropriate Use Criteria Task Force, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, and Society of Thoracic Surgeons. J Thorac Cardiovasc Surg 2019;157:e131-61. [Crossref] [PubMed]
  8. Patel MR, Calhoon JH, Dehmer GJ, et al. ACC/AATS/AHA/ASE/ASNC/SCAI/SCCT/STS 2017 Appropriate Use Criteria for Coronary Revascularization in Patients With Stable Ischemic Heart Disease: A Report of the American College of Cardiology Appropriate Use Criteria Task Force, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, and Society of Thoracic Surgeons. J Nucl Cardiol 2017;24:1759-92. [Crossref] [PubMed]
  9. Zhan J, Zhong L, Wu J. Assessment and Treatment for Coronary Microvascular Dysfunction by Contrast Enhanced Ultrasound. Front Cardiovasc Med 2022;9:899099. [Crossref] [PubMed]
  10. Caiati C. Contrast-Enhanced Ultrasound Reveals That Lipoprotein Apheresis Improves Myocardial But Not Skeletal Muscle Perfusion. JACC Cardiovasc Imaging 2019;12:1441-3. [Crossref] [PubMed]
  11. Heitz C, Challen K, Milne WK. Hot off the press: SGEM#370: Listen to your HEART (score) … MACE incidence in non-low-risk patients with known coronary artery disease. Acad Emerg Med 2022;29:1138-9. [Crossref] [PubMed]
  12. Shang S, Liu Z, Gao J, et al. The Relationship Between Pre-existing Coronary Heart Disease and Cognitive Impairment Is Partly Explained by Reduced Left Ventricular Ejection Fraction in the Subjects Without Clinical Heart Failure: A Cross-Sectional Study. Front Hum Neurosci 2022;16:835900. [Crossref] [PubMed]
  13. Arques S. Deterioration in Left Ventricular Systolic Function in Heart Failure With Preserved and Midrange Ejection Fraction: Don't Miss Coronary Artery Disease. Am J Cardiol 2019;124:1806. [Crossref] [PubMed]
  14. Fu M, Zhou D, Tang S, et al. Left atrial volume index is superior to left atrial diameter index in relation to coronary heart disease in hypertension patients with preserved left ventricular ejection fraction. Clin Exp Hypertens 2020;42:1-7. [Crossref] [PubMed]
  15. Zhang X, Sun T, Liu E, et al. Development and evaluation of a radiomics model of resting (13)N-ammonia positron emission tomography myocardial perfusion imaging to predict coronary artery stenosis in patients with suspected coronary heart disease. Ann Transl Med 2022;10:1167. [Crossref] [PubMed]
  16. Aldiwani H, Nelson MD, Sharif B, et al. Reduced myocardial perfusion is common among subjects with ischemia and no obstructive coronary artery disease and heart failure with preserved ejection fraction: a report from the WISE-CVD continuation study. Vessel Plus 2022;6:16. [Crossref] [PubMed]
  17. Han X, Zhu W, Chen W. Evaluation of myocardial perfusion and systolic function in patients with coronary heart disease by myocardial contrast echocardiography and 2-dimensional speckle tracking imaging. Zhong Nan Da Xue Xue Bao Yi Xue Ban 2021;46:1233-40. [Crossref] [PubMed]
  18. Knieling F, Rüffer A, Cesnjevar R, et al. Transfontanellar Contrast-Enhanced Ultrasound for Monitoring Brain Perfusion During Neonatal Heart Surgery. Circ Cardiovasc Imaging 2020;13:e010073. [Crossref] [PubMed]
  19. Fischer K, Ohori S, Meral FC, et al. Testing the Efficacy of Contrast-Enhanced Ultrasound in Detecting Transplant Rejection Using a Murine Model of Heart Transplantation. Am J Transplant 2017;17:1791-801. [Crossref] [PubMed]
  20. Chen T, Zhou H, Guo J, et al. Intravascular ultrasound and ultrasonic flow ratio-guided zero-contrast rotational atherectomy for calcified coronary lesions. Eur Heart J 2023;44:166. [Crossref] [PubMed]
  21. Zhang H, Xu B, Song L. Intravascular ultrasound and ultrasonic flow ratio-guided zero-contrast percutaneous coronary intervention: first report of a novel technique treating a patient with obstructive coronary artery disease and contrast allergy. Coron Artery Dis 2022;33:148-50. [Crossref] [PubMed]
  22. He XC, Chen HY, Qiu Y, et al. Associations of iron status with breast cancer risk factors in adult women: Findings from National Health and Nutrition Examination Survey 2017-2018. J Trace Elem Med Biol 2021;68:126867. [Crossref] [PubMed]
  23. Qiu Y, Chen H, Dai Y, et al. Nontherapeutic Risk Factors of Different Grouped Stage IIIC Breast Cancer Patients' Mortality: A Study of the US Surveillance, Epidemiology, and End Results Database. Breast J 2022;2022:6705052. [Crossref] [PubMed]
  24. Chen Y, Si H, Bao B, et al. Integrated analysis of intestinal microbiota and host gene expression in colorectal cancer patients. J Med Microbiol 2022; [Crossref]
  25. Qiu Y, Dai Y, Zhu L, et al. Clinicopathological Characteristics and Prognostic Profiles of Breast Carcinoma with Neuroendocrine Features. Life (Basel) 2023;13:532. [Crossref] [PubMed]
Cite this article as: Li J, Ma C, Sun H, Li F, She Y, Yi T. Effect of quantitative parameters of contrast-enhanced ultrasound on the long-term prognosis of patients with chronic coronary syndrome. J Thorac Dis 2023;15(12):6806-6812. doi: 10.21037/jtd-23-1267

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