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Published on: June 28, 2019
Role of collateral flow in infarct border zone extent and contractile function in patients with chronic coronary
Yin-Yin Chen1, Shi-Hai Zhao2, Dao-Yuan Ren3
1Department of Radiology, Zhongshan Hospital (Xiamen), Fudan University, Xiamen 361015, China; Department of Radiology, Zhongshan Hospital, Fudan University and Shanghai Institute of Medical Imaging, Shanghai 200032, China; Department of Medical Imaging, Shanghai Medical school, Fudan University, Shanghai 200032, China.
Insights
In chronic coronary total occlusion (CTO), well-developed collateral flow improves border zone extent and contractile function. Cardiac MRI reveals these associations, offering prognostic insights for CTO patients.
Area of Science:
- Cardiovascular Imaging
- Myocardial Viability Assessment
- Coronary Artery Disease Pathophysiology
Background:
- Chronic coronary total occlusion (CTO) presents a significant clinical challenge with limited data on border zone characteristics.
- Understanding the border zone's extent and function is crucial for assessing myocardial viability and patient outcomes in CTO.
Purpose of the Study:
- To investigate the border zone extent and contractile function in patients with CTO.
- To explore the association between collateral flow and these border zone parameters using cardiac MRI.
Main Methods:
- Cardiac MRI including cine and late-gadolinium enhancement (LGE) was performed on 47 CTO patients and 15 controls.
- Myocardial peak strain (PS) and time to PS were analyzed segmentally and globally.
- Border zone, infarct, adjacent, and remote regions were defined by LGE transmural extent (TEI); collateral flow was graded using the Rentrop system.
Main Results:
- Patients with well-developed collaterals showed higher TEI in border zones (p=0.02) and enhanced border function (greater PS, earlier time to PS).
- Conversely, poorly developed collaterals correlated with higher TEI in infarct regions (p<0.01).
- Collateral flow independently predicted border zone extent and contractile function (radial, circumferential, longitudinal) in multivariate analyses.
Conclusions:
- Well-developed collateral flow in CTO patients is associated with a larger border zone extent and preserved contractile function.
- Cardiac MRI provides insights into the pathophysiological mechanisms within border zones in CTO.
- These findings may offer valuable complementary prognostic information for clinical practice.
Purpose:
There is a paucity of data regarding the border zone parameters in patients with chronic coronary total occlusion (CTO). We investigated the border zone extent and contractile function and their associations with collateral flow.
Methods:
CTO patients (n = 47) and sex- and age-matched volunteers (n = 15) were prospectively enrolled and underwent cardiac MRI examinations to acquire cine and late-gadolinium enhancement (LGE) images. Myocardial peak strain (PS) and the time to PS were determined at the segmental level and global level. Infarct, border zone, adjacent, and remote regions were defined according to the transmural extent of infarction (TEI) by LGE at each segment. Angiographic collateral flow was evaluated using the Rentrop grading system.
Results:
CTO patients with well-developed collateral flow had a higher TEI in border zone regions compared to patients with poorly developed collateral flow (p = 0.02). Conversely, CTO patients with poorly developed collaterals showed a higher TEI in infarct regions (p < 0.01). Enhanced border function, characterized by greater PS and earlier time to PS, was noted in well-developed collaterals (all p < 0.05). In the multivariate linear analyses, the level of collateral flow was an independent predictor of the border zone extent (β = 0.40, p = 0.02) and contractile function (radial: β = -0.42, p = 0.02; circumferential: β = 0.39, p = 0.02; and longitudinal: β = 0.47, p < 0.01).
Conclusions:
In CTO patients, the presence of well-developed collateral flow was closely linked to a greater extent of LGE and contractile function in border zone regions. Our findings shed light on the cardiac MRI-based pathophysiological underpinning in border zone regions, which could offer complementary and prognostic information in clinical practice.
