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Influence on collateral flow of recanalising chronic total coronary occlusions: a case-control study
T Pohl1, P Hochstrasser, M Billinger
1Cardiology, Swiss Cardiovascular Centre Bern, University Hospital, CH-3010 Bern, Switzerland.
Insights
Recanalisation of chronic total coronary occlusions often reduces collateral flow, unlike moderate stenoses where it may increase. This study compared collateral flow changes after percutaneous transluminal coronary angioplasty in patients with occlusions versus stenoses.
Area of Science:
- Cardiovascular Medicine
- Interventional Cardiology
- Coronary Artery Disease
Background:
- Coronary collateral circulation plays a vital role in myocardial perfusion, especially in cases of significant coronary artery stenosis or occlusion.
- Understanding the impact of revascularization procedures on collateral flow is crucial for optimizing patient outcomes.
Purpose of the Study:
- To evaluate the effect of recanalisation on coronary collateral flow in patients with chronic total coronary occlusions compared to those with significant stenoses.
Main Methods:
- A case-control study involving 54 patients undergoing percutaneous transluminal coronary angioplasty (PTCA).
- Coronary collateral flow was measured using intracoronary pressure or Doppler guide wires during repeated balloon occlusions.
- Patients were divided into an occlusion group (chronic total occlusion) and a stenosis group (stenosis <= 80%).
Main Results:
- Recanalisation was associated with a decrease in collateral flow index in 63% of the chronic total occlusion group versus 30% in the stenosis group (p=0.03).
- The occlusion group showed a trend towards reduced collateral flow (change of -0.04, p=0.07), while the stenosis group showed a trend towards enhanced collateral flow (change of +0.02, p=0.06).
- The differing trends in collateral flow between the two groups were statistically significant (p=0.01).
Conclusions:
- Recanalisation of chronic total coronary occlusions is frequently linked to a reduction in collateral flow.
- In contrast, repeated balloon occlusions tend to induce collateral recruitment in patients with moderate coronary stenoses.
- The potential for late decrease in collateral flow due to involution of collateral channels warrants further investigation.
Objective:
To assess the effect of recanalisation on collateral flow in a case-control study in patients with and without chronic total coronary occlusions.
Design:
In 54 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) (mean (SD) age 61 (6) years), coronary collateral flow was measured by intracoronary pressure or Doppler guide wires at the end of repeated balloon occlusions. Coronary collateral flow index (collateral flow relative to normal antegrade flow) during the first two balloon inflations in 27 patients with a chronic total occlusion (occlusion group) was compared with that of 27 patients matched for age, sex, and collateral flow index at the first occlusion and with a coronary artery diameter stenosis
Results:
Following revascularisation, collateral flow index decreased in 17 of the patients in the occlusion group (63%) and in eight of the patients in the stenosis group (30%) (p = 0.03 between groups). The overall change of collateral flow index between the first and the second balloon occlusion was -0.04 (0.01) in the occlusion group (p = 0.07 for paired comparison; from 0.29 (0.17) to 0.25 (0.14)), and +0.02 (0.06) in the stenosis group (p = 0.06 for paired comparison; from 0.27 (0.13) to 0.30 (0.15)). The trend to collateral enhancement in the stenosis group differed significantly from the occlusion group (p = 0.01).
Conclusions:
While repeated coronary balloon occlusions induce collateral recruitment in the majority of patients with moderate stenoses, recanalisation of chronic total coronary occlusions is more often associated with collateral flow reduction. A later decrease in collateral flow by involution of collateral channels cannot be excluded by this study but has not been reported so far.