Assessment of Diagonal Branch Territory

Study Overview
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Brief Summary
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This study was performed to investigate the anatomical attributes that determine myocardial territory of diagonal branches and to develop a prediction model for clinically relevant branches using myocardial perfusion imaging (MPI) and coronary CT angiography (CCTA).

Detailed Description
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Bifurcation lesion is one of the most challenging lesion subsets in the field of percutaneous coronary intervention (PCI). Despite the recent advances in PCI techniques and stent technology, most randomized studies failed to prove the superiority of systematic 2 stenting strategy compared with provisional side branch intervention strategy. A certain amount of ischemic burden is required to achieve the benefit of revascularization over medical treatment. Compared with major epicardial vessels, side branches are smaller, more variable in anatomy, supplying less myocardium and less clinically relevant. Therefore, it is important to assess the myocardial mass at risk of side branches to determine the appropriate treatment strategy for bifurcation lesions. However, how to define the clinically relevant side branches which can be associated with the benefit of revascularization in a cardiac catheterization laboratory is not well-known. The investigators performed this study to investigate the anatomical attributes that determine ischemic burden and myocardial territory of diagonal branches and to develop a prediction model for a clinically relevant diagonal branch using myocardial perfusion imaging (MPI) and coronary CT angiography (CCTA).

Official Title
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Anatomical Attributes of Clinically Relevant Diagonal Branches in Patients With Left Anterior Descending Coronary Artery Bifurcation Lesions

Conditions
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Stable Angina, Unstable Angina

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with severe jailed diagonal branch disease with available MPI in 3 months (MPI arm) Patients who had available FMM value of diagonal branches from a previous multicenter prospective CCTA registry (CCTA arm) Exclusion Criteria: Patients with >50% stenosis at left anterior descending coronary artery (LAD) or left circumflex artery (LCx), regional wall motion abnormality at LAD territory (MPI arm) Patients with diffuse diagonal branch disease (CCTA arm)

Ages Eligible for Study
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Minimum Age: 20 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| MPI arm<br>For the MPI arm, patients with severe jailed diagonal branch disease with available MPI in 3 months were selected from the Seoul National University Hospital Cardiac Catheterization and MPI database. | |
| CCTA arm<br>For the CCTA arm, patients from a previous multicenter prospective CCTA registry were retrospectively reviewed for a post-hoc analysis. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Angiographic attributes for diagonal branches | Angiographic attributes for diagonal branches were visually defined as follows : Size was a binary attribute of vessel diameter ≥ 2.5mm or < 2.5mm. Number was counted as one, two, and 3 or more diagonal branches. Dominancy in patients with 2 diagonal branches (D1/2 dominancy) was a binary attribute for one of two diagonal branches whose diameter was more than two times larger than its smaller counterpart. LCx dominancy was defined as a left-dominant system or a presence of obtuse marginal branch originating within proximal 1/3 of LCx and crossing LAD at right anterior oblique caudal view. | through study completion, an average of 1year | 
| Sensitivity of prediction model | Prediction model using anatomical attributes to define clinical relevance of diagonal branches will be developed. | through study completion, an average of 1year | 
| Specificity of prediction model | Prediction model using anatomical attributes to define clinical relevance of diagonal branches will be developed. | through study completion, an average of 1year | 
| Negative predictive value of prediction model | Prediction model using anatomical attributes to define clinical relevance of diagonal branches will be developed. | through study completion, an average of 1year | 
| Positive predictive value of prediction model | Prediction model using anatomical attributes to define clinical relevance of diagonal branches will be developed. | through study completion, an average of 1year | 
| Area under the curve of prediction model | Prediction model using anatomical attributes to define clinical relevance of diagonal branches will be developed. | through study completion, an average of 1year | 
| Accuracy of prediction model | Prediction model using anatomical attributes to define clinical relevance of diagonal branches will be developed. | through study completion, an average of 1year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| %Ischemia | Myocardium of perfusion image was divided into 20 segments, and summed rest score (SRS), summed stress score (SSS), and summed difference score (SDS) were scored in each segment according to a 5-grade system (0-4) for the assessment of perfusion status. (1) SSS and SDS of diagonal segments were converted to percent of myocardial ischemia (%ischemia) of diagonal territory by dividing summed scores by 80 and multiplying by 100. | through study completion, an average of 1year | 
| %FMM | FMM was calculated using stem-and-crown model as described in the parent study. (2) FMM of each diagonal brach was converted to percent FMM (%FMM) of diagonal branch by dividing each FMM by left ventricular myocardial mass. | through study completion, an average of 1year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Bifurcation, Side branch, Ischemia, Myocardium, Revascularization