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Quantification of left ventricular performance during transient coronary occlusion at various anatomic sites in
M S Verani1, J L Lacy, G W Guidry
1Department of Medicine, Baylor College of Medicine, Houston, Texas 77030.
Insights
Transient coronary occlusion significantly impairs left ventricular function, especially when the left anterior descending artery is affected. Collateral circulation offers a protective effect during these occlusions.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Interventional Cardiology
Background:
- Transient coronary occlusion during angioplasty provides a unique model to assess left ventricular (LV) function.
- Understanding the impact of occlusion site on LV function is crucial for patient management.
Purpose of the Study:
- To evaluate the functional significance of transient coronary occlusion on systolic and diastolic LV function.
- To determine the influence of the anatomic site of occlusion on these functional changes.
Main Methods:
- First-pass radionuclide angiography using tantalum-178 was performed in 46 patients undergoing balloon coronary angioplasty.
- Images were acquired before and during 60-second balloon inflations in various coronary arteries (LAD, RCA, Cx, Diagonal).
Main Results:
- Left anterior descending artery (LAD) occlusion caused significant decreases in LV ejection fraction and peak filling rate.
- Right coronary artery (RCA) and circumflex (Cx) artery occlusions had less impact on global LV function.
- Collateral supply was associated with a smaller decrease in LV ejection fraction during occlusion.
Conclusions:
- The LAD plays a critical role in maintaining global systolic and diastolic LV function.
- Other coronary arteries have a secondary role, and collateral vessels protect LV function during occlusion.
Abstract:
To study the functional significance of transient coronary occlusion on systolic and diastolic left ventricular function relative to the anatomic site of occlusion, first-pass radionuclide angiography with a mobile multiwire gamma camera using tantalum-178 (dose activity less than or equal to 84 mCi/elution) was performed in 46 patients undergoing balloon coronary angioplasty. First-pass images were acquired immediately before angioplasty and during the last 30 s of a 60-s balloon inflation in 23 left anterior descending arteries, 18 right coronary arteries, 8 circumflex arteries and 3 diagonal coronary arteries. Occlusion of the left anterior descending artery resulted in significant decreases in left ventricular ejection fraction (54.6 +/- 12.7% to 32.3 +/- 10.6%, p = 0.0001) and peak filling rate (2.48 +/- 0.68 to 1.75 +/- 0.64 end-diastolic volumes/s, p = 0.0001), accompanied by severe abnormalities in regional function and left ventricular dilation. Right coronary artery occlusion caused inferior hypokinesia, but did not significantly change left ventricular ejection fraction (48.5 +/- 12.4% vs. 45.8 +/- 12.5%, p = NS) or peak filling rate (2.05 +/- 0.81 vs. 2.09 +/- 0.81 end-diastolic volumes/s, p = NS). Circumflex artery occlusion resulted in mild wall motion deterioration and a borderline decrease in ejection fraction (54.7 +/- 11.4% to 50.5 +/- 12%, p = 0.057). Diagonal artery occlusion did not cause significant changes in left ventricular ejection fraction or filling rate. The decrease in left ventricular ejection fraction during coronary occlusion was 9 +/- 25% and 27 +/- 22%, respectively, in those arteries with and without collateral supply (p = 0.052). These data provide strong evidence for the critical importance of the left anterior descending artery and the secondary role of the other coronary arteries in maintaining global systolic and diastolic left ventricular function and suggest a protective role of collateral vessels during coronary occlusion.