Myocardial infarction caused by distal embolisation of a ruptured left main plaque

A case of acute myocardial infarction caused by distal embolization of a left main coronary artery thrombus

Coronary embolism is an uncommon cause of myocardial infarction. A 48-year-old male presented with typical chest pain of an MI. There was no definite ST segment change on electrocardiogram (ECG) and no elevation of myocardial enzymes. Coronary angiography (CAG) revealed occlusion of the distal left anterior descending coronary artery (dLAD), the distal left circumflex coronary artery (dLCX), the diagonal branch (D) and the obtuse marginal branch (OM), with a large filling defect in the left main coronary artery (LMA) that caused the myocardial infarction. We considered the possibility that coronary embolization was caused by the migration of a thrombus in the LMA during CAG. We did balloon angioplasty in the dLAD, dLCX, OM and D and treated the patient with glycoprotein IIb/IIIa receptor antagonist. However, thrombi remained in the dLAD, OM, and dLCX. After 3 days of anti-thrombotic treatment, follow-up CAG revealed only slight resolution of thrombi in the LAD. After triple antiplatelet agent medication for 1 year, a follow-up CAG showed a resolution of the thrombi in all coronary arteries.

Autocrine VEGF signaling is required for vascular homeostasis

Vascular endothelial growth factor (VEGF) is essential for developmental and pathological angiogenesis. Here we show that in the absence of any pathological insult, autocrine VEGF is required for the homeostasis of blood vessels in the adult. Genetic deletion of vegf specifically in the endothelial lineage leads to progressive endothelial degeneration and sudden death in 55% of mutant mice by 25 weeks of age. The phenotype is manifested without detectable changes in the total levels of VEGF mRNA or protein, indicating that paracrine VEGF could not compensate for the absence of endothelial VEGF. Furthermore, wild-type, but not VEGF null, endothelial cells showed phosphorylation of VEGFR2 in the absence of exogenous VEGF. Activation of the receptor in wild-type cells was suppressed by small molecule antagonists but not by extracellular blockade of VEGF. These results reveal a cell-autonomous VEGF signaling pathway that holds significance for vascular homeostasis but is dispensable for the angiogenic cascade.