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Regional left ventricular function during transient coronary occlusion: relation with coronary collateral flow
1Cardiology, Swiss Cardiovascular Centre Bern, University Hospital, Bern, Switzerland. christian.seiler.cardio@insel.ch
Insights
Regional left ventricular (LV) function during coronary artery angioplasty is directly linked to collateral blood flow. Adequate collateral flow preserves LV function during brief occlusions, crucial for preventing ischemia.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Interventional Cardiology
Background:
- Assessing regional left ventricular (LV) function during percutaneous transluminal coronary angioplasty (PTCA) is vital.
- Collateral circulation plays a key role in myocardial protection during coronary occlusion.
Purpose of the Study:
- To investigate the relationship between regional LV function and collateral blood flow during PTCA.
- To test if collateral flow amount predicts LV functional changes during temporary coronary artery occlusion.
Main Methods:
- Prospective study in 50 patients with coronary artery disease undergoing PTCA.
- Regional systolic and diastolic LV function assessed by tissue Doppler ultrasound (TD) during 60-second occlusions.
- Collateral flow index (CFI) calculated using pressure-derived measurements.
Main Results:
- Significant differences in TD-derived LV function parameters between patients with sufficient and insufficient collateral flow.
- Direct correlations found between CFI and measures of regional systolic and diastolic function.
- LV systolic excursion velocity and diastolic function correlated with collateral flow.
Conclusions:
- Regional LV systolic and diastolic function during brief coronary occlusions are directly related to collateral flow.
- Collateral circulation is a key determinant of myocardial function preservation during PTCA.
Objective:
To test the hypothesis that regional left ventricular (LV) function during balloon angioplasty is related to the amount of collateral flow to the ischaemic region.
Design:
Prospective study.
Setting:
Tertiary referral centre.
Methods:
In 50 patients with coronary artery disease and without myocardial infarction, regional systolic and diastolic LV function was determined using tissue Doppler ultrasound (TD) before and at the end of a 60 second occlusion of a stenotic lesion undergoing percutaneous transluminal coronary angioplasty (PTCA) through a pressure guidewire. The study population was subdivided into a group with collaterals insufficient (n = 33) and one with collaterals sufficient (n = 17) to prevent ECG ST shifts suggestive of myocardial ischaemia during PTCA. Pulsed TD was performed from an apical window in the myocardial region supplied by the vessel being treated by PTCA. Pressure derived collateral flow index (CFI) was determined by simultaneous measurement of mean aortic (P(ao)) and distal intracoronary occlusive pressures (P(occl)), where CFI = (P(occl) - 8)/(P(ao) - 8).
Results:
At 60 seconds of occlusion, several parameters of systolic and diastolic TD derived LV long axis function were significantly different between the groups. Also, there was a significant correlation between regional systolic excursion velocity, early diastolic excursion velocity, regional isovolumetric relaxation time, and CFI.
Conclusion:
During brief coronary artery occlusions, regional systolic and diastolic LV function is directly related to the amount of collateral flow to this territory.