Key result
Ischemic conditioning in porcine LAD occlusion leaves septal infarcts ~29% larger than the anterior wall.
Why the study?
It is unclear whether regional differences in LAD perfusion territories impact infarct size and the magnitude of cardioprotection by ischemic conditioning.
Does ischemic conditioning reduce infarct size equally in the septum and anterior free wall in a pig model of LAD occlusion?
Does ischemic conditioning reduce infarct size equally in the septum and anterior free wall in a pig model of LAD occlusion?
Ischemic conditioning effectively reduces infarct size in both septal and anterior free wall myocardium despite a slightly greater susceptibility for infarction in the septum.
Answers are grounded in this paper and cite their sources.
Greater septal infarct susceptibility in pigs does not blunt conditioning protection; hypothesis-generating for regional effects in human LAD infarction.
The ischemic area at risk (AAR) is one major determinant of infarct size (IS). In patients, the largest AAR is seen with a proximal occlusion of the left anterior descending (LAD) coronary artery, which serves parts of the septum and of the anterior free wall. It is not clear, whether regional differences in the perfusion territories also impact on IS and the magnitude of cardioprotection by ischemic conditioning. We have retrospectively analyzed 132 experiments in pigs, which have a similar LAD perfusion territory as humans. The LAD was occluded for 60 min with subsequent 180 min reperfusion. Cardioprotection by either local ischemic pre- or postconditioning or remote ischemic pre- or perconditioning was induced in 93 pigs. The AAR was demarcated by blue dye staining, and IS was assessed by triphenyltetrazolium chloride (TTC) staining. Using digital planimetry, the AAR was separated into sections unequivocally located in the septum (AARS) or the anterior free wall (AARAFW). Relative IS was calculated for AARS or AARAFW. AARAFW was larger than AARS (51 ± 9% vs. 34 ± 8% of total AAR; mean ± SD, P < 0.001). Regional myocardial blood flow (microspheres) was not different between septum and anterior free wall. IS without ischemic conditioning tended to be larger in AARS than in AARAFW (50 ± 17% vs. 44 ± 19%; % of AARAWF or AARS, respectively; P = 0.075). Also, with robust IS reduction by ischemic conditioning, the difference in relative IS remained (AARS: 27 ± 16%; AARAFW: 21 ± 16%; P = 0.01). There is a somewhat greater susceptibility for infarction in septal than anterior free wall myocardium. However, ischemic conditioning still reduces IS in both septal and anterior free wall myocardium.
No takes yet. Share an insight, caveat, or question.
Skyschally et al. (2019) studied LAD occlusion (n=132). Septal myocardium (AARS) vs. Anterior free wall myocardium (AARAFW) was evaluated on Relative infarct size with ischemic conditioning (p=0.01). In pigs with LAD occlusion, relative infarct size following ischemic conditioning remained larger in the septal myocardium compared to the anterior free wall (27% vs 21%; P=0.01).
Synapse has enriched 10 related papers. Consider them for comparative context: