Key result
Repeated balloon inflations fail to reduce ST segment elevation despite collateral recruitment in swine.
Why the study?
Attempts to demonstrate preconditioning during repeated angioplasty balloon inflations have not been universally successful due to variability in the first balloon inflation occlusion.
Do repeated angioplasty balloon inflations diminish ST segment elevation and promote coronary collateral recruitment in pigs?
Do repeated angioplasty balloon inflations diminish ST segment elevation and promote coronary collateral recruitment in pigs?
Repeated balloon inflations in a pig model promote coronary collateral recruitment but do not diminish ST segment elevation, suggesting a disconnect between collateral flow and ischemic ECG changes in this model.
Collateral recruitment without ST reduction in pig model questions preconditioning assumptions; hypothesis-generating and should not guide clinical practice.
Objective: Attempts to demonstrate preconditioning during repeated angioplasty balloon inflations (BIs) have not been universally successful. The main obstacle is that the first BI is unreliable, due to the variable degrees of occlusion by the deflated balloon. In the present study, we examined whether ST segment elevation decreases and evaluated its relation to collateral recruitment during repeated angioplasty BIs in the pig. Methods and Results: Twenty male pigs, 7 months old, under general anesthesia, underwent 3 repeated BIs of 120 s, with a 5-min interval between them, in the left anterior descending artery or the right coronary artery. A pressure wave wire was used for the measurement of coronary wedge pressure and to obtain the intracoronary ST segment elevation. Intracoronary ST segment elevation was 1.97 ± 0.76 mV during the 1st BI, 2.09 ± 0.82 mV during the 2nd BI and 1.84 ± 0.82 mV during the 3rd BI (p = n.s.). Coronary wedge pressure was 12 ± 6, 18 ± 18 and 20 ± 20 mm Hg (p < 0.05 vs. 1st BI) during the 3 BIs, respectively. Conclusion: Repeated BIs do not diminish ST segment elevation in the pig model, even though coronary collateral recruitment is promoted.
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Lyras et al. (2007) studied Coronary angioplasty model (n=20). Repeated angioplasty balloon inflations vs. First balloon inflation (baseline reference) was evaluated on Intracoronary ST segment elevation (p=n.s.). Repeated balloon inflations in a pig model did not diminish ST segment elevation (1.97 mV during 1st inflation vs 1.84 mV during 3rd inflation, p=n.s.), despite promoting collateral recruitment.
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