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Updated: Aug 27, 2025
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Collateral presence and extent do not predict myocardial viability and ischemia in chronic total occlusions: A
S Pica1, L Di Odoardo1, L Testa2
1Multimodality Cardiac Imaging Section, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy.
Insights
Well-developed collaterals do not predict myocardial viability or ischemia in chronic total occlusions (CTO). Cardiac magnetic resonance (CMR) assessment is crucial for comprehensive evaluation to guide revascularization strategies.
Area of Science:
- Cardiology
- Medical Imaging
Background:
- Collateral circulation is often considered a marker for myocardial viability and ischemia in patients with chronic total occlusions (CTO).
- The relationship between collateral presence and extent, and actual viability/ischemia in CTO requires further investigation.
Purpose of the Study:
- To correlate the presence and extent of collateral circulation with myocardial viability and ischemia in CTO patients using cardiac magnetic resonance (CMR).
Main Methods:
- A multicentre study involving 150 CTO patients who underwent stress-CMR and late gadolinium enhancement (LGE) imaging.
- Stress-CMR protocols included adenosine or dobutamine, tailored to patient's systolic function and ejection fraction.
- Viability was assessed by LGE transmurality or functional improvement, while ischemia was defined by perfusion defects outside scar zones.
Main Results:
- No significant difference in viability or ischemia was observed between patients with well-developed (WD) versus poorly-developed (PD) collaterals.
- Myocardial viability was present in segments with up to 75% LGE, but significantly decreased with >75% LGE.
- Ischemia was present in a similar proportion of patients regardless of collateral development, and 25% of patients had undetectable ischemia.
Conclusions:
- Collateral presence and extent do not reliably predict myocardial viability or ischemia in CTO patients as assessed by stress-CMR.
- Significant myocardial viability can exist even with extensive scar (up to 75% LGE).
- Comprehensive CMR assessment is essential for accurate evaluation of viability and ischemia to guide revascularization decisions in CTO patients.
Background:
Well-developed collaterals are assumed as a marker of viability and ischemia in chronic total occlusions (CTO). We aim to correlate viability and ischemia with collateral presence and extent in CTO patients by cardiac magnetic resonance (CMR).
Methods:
Multicentre study of 150 CTO patients undergoing stress-CMR, including adenosine if normal systolic function, high-dose-dobutamine for patients with akinetic/>2 hypokinetic segments and EF ≥35%, otherwise low-dose-dobutamine (LDD); all patients underwent late gadolinium enhancement (LGE) imaging. Viability was defined as mean LGE transmurality ≤50% for adenosine, as functional improvement for dobutamine-stress-test, ischemia as ≥1.5 segments with perfusion defects outside the scar zone.
Results:
Rentrop 3/CC 2 defined well-developed (WD, n = 74) vs poorly-developed collaterals (PD, n = 76). Viability was equally prevalent in WD vs PD: normo-functional myocardium with ≤50% LGE in 52% vs 58% segments, p = 0.76, functional improvement by LDD in 48% vs 52%, p = 0.12. Segments with none, 1-25%,26-50%,51-75% LGE showed viability by LDD in 90%,84%,81%,61% of cases, whilst in 12% if 76-100% LGE (p < 0.01). There was no difference in WD vs PD for ischemia presence (74% vs 75%, p = 0.99) and extent (2.7 vs 2.8 segments, p = 0.77).
Conclusions:
In a large cohort of CTO patients, presence and extent of collaterals did not predict viability and ischemia by stress-CMR. Scar extent up to 75% LGE was still associated with viability, whereas ischemia was undetectable in 25% of patients, suggesting that the assessment of CTO patients with CMR would lead to a more comprehensive evaluation of viability and ischemia to guide revascularization.
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