Prevalence and extent of infarct and microvascular obstruction following different reperfusion therapies in ST-elevation myocardial infarction

Abstract

BackgroundMicrovascular obstruction (MVO) describes suboptimal tissue perfusion despite restoration of infarct-related artery flow. There are scarce data on Infarct Size (IS) and MVO in relation to the mode and timing of reperfusion. We sought to characterise the prevalence and extent of microvascular injury and IS using Cardiovascular magnetic resonance (CMR), in relation to the mode of reperfusion following acute ST-Elevation Myocardial Infarction (STEMI).MethodsCMR infarct characteristics were measured in 94 STEMI patients (age 61.0 ± 13.1 years) at 1.5 T. Seventy-three received reperfusion therapy: primary percutaneous coronary-intervention (PPCI, n = 47); thrombolysis (n = 12); rescue PCI (R-PCI, n = 8), late PCI (n = 6). Twenty-one patients presented late (>12 hours) and did not receive reperfusion therapy.ResultsIS was smaller in PPCI (19.8 ± 13.2% of LV mass) and thrombolysis (15.2 ± 10.1%) groups compared to patients in the late PCI (40.0 ± 15.6%) and R-PCI (34.2 ± 18.9%) groups, p <0.001. The prevalence of MVO was similar across all groups and was seen at least as frequently in the non-reperfused group (15/21, [76%] v 33/59, [56%], p = 0.21) and to a similar magnitude (1.3 (0.0-2.8) v 0.4 [0.0-2.9]% LV mass, p = 0.36) compared to patients receiving early reperfusion therapy. In the 73 reperfused patients, time to reperfusion, ischaemia area at risk and TIMI grade post-PCI were the strongest independent predictors of IS and MVO.ConclusionsIn patients with acute STEMI, CMR-measured MVO is not exclusive to reperfusion therapy and is primarily related to ischaemic time. This finding has important implications for clinical trials that use CMR to assess the efficacy of therapies to reduce reperfusion injury in STEMI.

The randomised Complete versus Lesion-only PRimary percutaneous coronary Intervention Trial: Cardiovascular Magnetic Resonance imaging substudy (CvLPRIT-CMR)

“…Time to revascularisation 82 and anterior MI 83,84 are strongly associated with IS and, therefore, randomisation was stratified by these variables. The clinical event rates in CMR imaging participants was inevitably lower than that in those not participating in the CMR imaging substudy, largely because of the fact that some patients died or were too ill to take part.…”

Factors Affecting Time to Presentation in ST-Elevation Myocardial Infarction(FAT STEMI)

“…Survival after ST-Elevation Myocardial Infarction (STEMI) has improved due to continued improvements in medical therapy from thrombolytic therapy use to, now more routine, primary percutaneous coronary intervention [1][2]. Additionally, improvements in system based care have led to decreased emergency room door to balloon times.…”

Invasive reperfusion after 12 hours of the symptom onset remains beneficial in patients with ST-segment elevation myocardial infarction: Evidence from a meta-analysis of published data

“…The remaining 21 studies were full-text reviewed, and 4 studies were excluded due to event rates not reported and outcomes of interest not reported. Finally, 18 studies [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] met the inclusion criteria and were included in the meta-analysis.…”