MR findings of microvascular perfusion in infarcted and remote myocardium early after successful primary PCI

Abstract

ObjectivesThe aim of the study was to evaluate CMR myocardial first-pass perfusion in the injured region as well as the non-infarcted area in ST-elevation myocardial infarction (STEMI) patients few days after successful primary percutaneous coronary intervention (PCI).Materials and methods220 patients with first time STEMI successfully treated with PCI (with or without postconditioning) were recruited from the Postconditioning in STEMI study. Contrast enhanced CMR was performed at a 1.5 T scanner 2 (1–5) days after PCI. On myocardial first-pass perfusion imaging signal intensity (SI) was measured in the injured area and in the remote myocardium and maximum contrast enhancement index (MCE) was calculated. MCE = (peak SI after contrast—SI at baseline) / SI at baseline x 100.ResultsThere were no significant differences in first-pass perfusion between patients treated with standard PCI and patients treated with additional postconditioning. The injured myocardium showed a significantly lower MCE compared to remote myocardium (94 ± 55 vs. 113 ± 49; p < 0.001). When patients were divided into four quartiles of MCE in the injured myocardium (MCE injured myocardium), patients with low MCE injured myocardium had: significantly lower ejection fraction (EF) than patients with high MCE injured myocardium, larger infarct size and area at risk, smaller myocardial salvage and more frequent occurrence of microvascular obstruction on late gadolinium enhancement. MCE in the remote myocardium revealed that patients with larger infarction also had significantly decreased MCE in the non-infarcted, remote area.ConclusionCMR first-pass perfusion can be impaired in both injured and remote myocardium in STEMI patients treated with primary PCI. These findings indicate that CMR first-pass perfusion may be a feasible method to evaluate myocardial injury after STEMI in addition to conventional CMR parameters.

Coronary microvascular dysfunction beyond microvascular obstruction in ST‐elevation myocardial infarction: Functional and clinical correlates

“…Perfusion defect in remote myocardium increased with increasing of MVO in infarcted myocardium. 11 Contrary to Bethke's study, we did not find linear relationship between MVO and MVD: It might confirm that MVD was more probably confined into peri-infarct than in remote myocardium. In this regard, a "stunning" of microcirculation within stunned myocardium might be the most conceivable explanation.…”

“…Indeed, only a semi-quantitative measure of MVD has been previously reported, by the signal intensity versus time during first-pass perfusion sequence before and after contrast injection. 11 We did not distinguish between peri-infarct and remote microcirculation, because MCE studies were analyzed by an operator blinded of clinical data. On the other hand, coronary territory often overlap in myocardial blood supply.…”

“…impact and predictors of MVD and MVO, both quantified by MCE, during the subacute phase of a first ST-elevation MI. The main findings can be summarized as follows: (1) In patients with limited MVO, presence, and extent of any MVD is not an innocent bystander, but it might contribute to the impairment of LVEF and the increase of LVEDV; (2) patients with limited MVO but large extent of MVD may have the same LV contractile impairment as those with large MVO (Figure 6, Central Illustration); (3) MVD and MVO are predicted by admission cTnT and peak cTnT, respectively, 10During the subacute phase of MI, greater MVO in infarcted myocardium is associated to lower LVEF and larger LVEDV 11. According to previously published results, extent of MVO in our study greatly correlates with LVEF and LVEDV.…”

Hemorrhage promotes chronic adverse remodeling in acute myocardial infarction: a T1, T2 and BOLD study

“…Our study lacked a gold standard technique for the assessment of vasodilator response (by T 2 BOLD), particularly to detect remote myocardial alterations; future work could validate findings against the histology‐based microsphere technique, which is considered the gold standard. Nevertheless, remote myocardial effects have been documented by us when evaluating the severity of infarcts 22,24,33 as well as by many others. 34,40,50–52 …”

“…Nevertheless, remote myocardial effects have been documented by us when evaluating the severity of infarcts 22,24,33 as well as by many others. 34,40,[50][51][52]…”