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Influence of clinical and angiographic factors on development of collateral channels
M J Mason1, S K Walker, D J Patel
1Department of Cardiology, Harefield Hospital, Middlesex, UK.
Insights
Coronary collateralization is primarily determined by stenosis severity and antegrade flow, not clinical history. Some patients develop significant collaterals even with good blood flow.
Area of Science:
- Cardiology
- Interventional Cardiology
- Vascular Biology
Background:
- Coronary collateralization is influenced by clinical and angiographic factors.
- Angina duration and frequency may impact collateral channel development.
Purpose of the Study:
- To assess clinical and angiographic factors influencing coronary collateralization.
- Investigate the relationship between symptoms and collateral development in patients with suspected coronary artery disease.
Main Methods:
- Study included 106 patients with suspected coronary artery disease, excluding those with prior bypass surgery or <50% stenosis.
- Quantified stenosis severity, antegrade flow (TIMI grade), and collaterals (Rentrop classification) using digital analysis.
Main Results:
- Collateralization correlated with >90% stenosis (r=0.65, P<0.001) and lower TIMI flow (r=0.86, P<0.01).
- 13% of patients had significant collaterals despite TIMI grade II/III flow; two had grade 2/3 collaterals with TIMI grade II/III flow.
- Collateralization was not linked to symptom chronicity/frequency, age, atherosclerosis risk factors, or presentation type.
Conclusions:
- Coronary collateralization cannot be predicted by clinical history alone.
- Stenosis severity and antegrade flow are key determinants of collateralization.
- High-grade collaterals can develop despite good antegrade flow in some individuals.
Background:
The degree of coronary collateralization is believed to be related to several clinical and angiographic factors. The duration and frequency of angina may be important factors in determining development of collateral channels.
Objective:
To assess these factors for a consecutive series of patients suspected to have coronary artery disease.
Methods:
Patients without at least one stenosis of < 50% and patients who had previously undergone bypass surgery were excluded from our study. Severity of stenosis was quantified by digital analysis, antegrade flow in terms of TIMI grade, and collaterals using the Rentrop classification.
Results:
We reviewed 106 patients [mean age 61 years (range 35-84), 77.6% men]. Of these, 22 (21%) had presented with an acute coronary syndrome on this admission, whilst 46 patients (43%) had previously had an acute coronary syndrome. Collaterals were more likely in patients with stenoses of > 90% (Spearman correlation 0.65, P < 0.001) in patients with lower than normal TIMI flow grade (Spearman correlation 0.86, P < 0.01) and were related to regions of hypokinesis (Spearman correlation 0.35, P < 0.01). Significant collaterals were present in 14 patients (13%) despite their having TIMI grade II/III flow. Two of these patients had grade 2/3 collaterals with TIMI grade II/III antegrade flow. Degree of collateralization was not related to chronicity and frequency of symptoms, age, risk factors for atherosclerosis and nature of presentation (i.e. acute or stable symptoms).
Conclusion:
The likelihood of coronary collateralization cannot be prospectively predicted from clinical history alone, but appears to be largely a function of severity of stenosis and level of antegrade flow. A few patients develop high-grade collateral channels despite the presence of good antegrade flow.