Well-Developed Coronary Collateral Circulation Is Associated With Higher Thrombus Burden in the Setting of ST-Segment Elevation Myocardial Infarction.

backgroundThis study investigated the relationship between coronary collateral circulation (CCC) and intracoronary thrombus burden in patients undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction (STEMI). CCC and thrombus burden are predictive of clinical outcomes in patients with STEMI.

methodsPatients with STEMI undergoing primary percutaneous coronary intervention were enrolled (n = 172). CCC was graded according to the Cohen-Rentrop classification. Patients were classified as insufficient (grade 0 or 1, n = 134) or well-developed (grade 2 or 3; n = 38) CCC. The Thrombolysis in Myocardial Infarction scale was used to evaluate intra-coronary thrombus burden. The low-thrombus-burden group comprised those with grades 0 to 2, and the high-thrombus-burden group comprised those with grades 3 or 4.

resultsRight coronary artery infarcts had a 13.830-fold higher chance of having well-developed CCC than did left anterior descending artery infarcts (P < .001). Circumflex artery infarcts had a 7.904-fold higher chance of well-developed CCC than did left anterior descending artery infarcts (P = .016). High thrombus burden was associated with a 4.393-fold higher chance for well-developed CCC than was low thrombus burden (P = .030). Low albumin levels were related to a greater chance of having well-developed CCC (P = .046).

conclusionPatients with well-developed CCC have higher thrombus burden than do those with insufficient CCC. Because well-developed CCC is an indicator of more severe underlying lesions, we speculate that patients with severe lesions are more prone to experience more complicated STEMI with high thrombus burden.