The importance of the determination of the myocardial area at risk in the evaluation of the outcome of acute myocardial infarction in patients.

Abstract

On the basis of animal studies, we postulated that the size of the perfusion field (risk area) of an occluded coronary artery would be an important determinant of outcome in patients with acute myocardial infarction. To test this hypothesis, we measured size of the risk area in 27 patients with acute myocardial infarction by the intracoronary injection of 9fmTc-macroaggregated albumin and gated nuclear imaging. After injection of the albumin spheres (5.3 + 1.4 hr after the onset of chest pain) streptokinase was administered and in 16 of 27 patients (59%) effective thrombolysis was achieved. Since none of the patients had evidence of a prior acute myocardial infarction, the 3 day nuclear left ventricular ejection fraction (LVEF) was considered an index of infarct size. Response to thrombolysis was analyzed according to success

Role of collateral circulation in the acute phase of ST-segment-elevation myocardial infarction treated with primary coronary intervention

“…In patients with anterior infarction the area of jeopardised myocardium is larger than in patients with inferior infarction. 23 So, although our results showed no protective effect on microvascular perfusion of collateral flow to acutely occluded non-LADrelated infarcts, there is still a possibility that this effect was present but that its detection is problematic due to the smaller area at risk. These findings are the first to support the hypothesis that the presence of collateral flow plays an important role in sustaining jeopardised myocardium until reperfusion is accomplished, even in the first hours after acute coronary occlusion.…”

Risk stratification by cardiac magnetic resonance imaging after ST-elevation myocardial infarction

“…Nevertheless, there are relevant advantages of quantifying the salvaged AAR as an indicator of therapeutic efficacy in clinical trials. Experimental and clinical studies have shown that the extent of AAR can differ widely, even in cases with a coronary artery occlusion in the same territory [78][79][80]. Theoretically, two patients with acute myocardial infarction may have substantial differences in the AAR, whereas the infarct size is similar.…”

Coronary Angiography

“…It should be noted that anatomical dominance does not imply physiological dominance. Although the right coronary artery is usually dominant, the left coronary almost always supplies a greater myocardial mass [ 182 ].…”

“…Using a method initially validated in the pig [ 225 ], Technetium 99 m radiolabeled albumin microspheres were injected directly into both coronary arteries of patients presenting with acute infarction during the period of total coronary occlusion and again following achievement of lumen patency after intracoronary thrombolysis [ 182 ]. Delayed scanning revealed perfusion defi cits which could be quantitated as the area at risk and correlated with the exact site of coronary occlusion determined with acute coronary angiography (Fig.…”