Late primary angioplasty (beyond 12 h): are we sure it should be avoided?

Optimal management for patients with ST-segment elevation myocardial infarction (STEMI) who arrive at a hospital late remains uncertain since evidence and real-world data are limited. Patients who present late with a STEMI are a heterogeneous population, and the clinical decision regarding percutaneous coronary intervention (PCI) should not be the same for all. One randomized clinical trial, multiple mechanistic studies, and contemporary registries suggest a presumed benefit for a prompt restoration of coronary flow even in late presenting STEMI. Crucial elements in decision-making are the presence of haemodynamic or electrical instability, and ongoing ischaemic signs or symptoms to tip the scales toward PCI. Among clinically stable, late-presenting patients, myocardial viability assessment and functional testing can identify yet another subgroup that may benefit from late PCI

Myocardial Infarction Quantification from Late Gadolinium Enhancement MRI Using Top-Hat Transforms and Neural Networks

Late gadolinium enhancement (LGE) MRI is the gold standard technique for myocardial viability assessment. Although the technique accurately reflects the damaged tissue, there is no clinical standard to quantify myocardial infarction (MI). Moreover, commercial software used in clinical practice are mostly semi-automatic, and hence require direct intervention of experts. In this work, a new automatic method for MI quantification from LGE-MRI is proposed. Our novel segmentation approach is devised for accurately detecting not only hyper-enhanced lesions, but also microvascular obstruction areas. Moreover, it includes a myocardial disease detection step which extends the algorithm for working under healthy scans. The method is based on a cascade approach where firstly, diseased slices are identified by a convolutional neural network (CNN). Secondly, by means of morphological operations a fast coarse scar segmentation is obtained. Thirdly, the segmentation is refined by a boundary-voxel reclassification strategy using an ensemble of very light CNNs. We tested the method on a LGE-MRI database with healthy (n = 20) and diseased (n = 80) cases following a 5-fold cross-validation scheme. Our approach segmented myocardial scars with an average Dice coefficient of 77.22 ± 14.3% and with a volumetric error of 1.0 ± 6.9 cm3. In a comparison against nine reference algorithms, the proposed method achieved the highest agreement in volumetric scar quantification with the expert delineations (p< 0.001 when compared to the other approaches). Moreover, it was able to reproduce the scar segmentation intra- and inter-rater variability. Our approach was shown to be a good first attempt towards automatic and accurate myocardial scar segmentation, although validation over larger LGE-MRI databases is needed.

Hybrid PET/MR imaging for the prediction of left ventricular recovery after percutaneous revascularisation of coronary chronic total occlusions

Purpose To evaluate myocardial viability assessment with hybrid 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography/magnetic resonance imaging ([18F]FDG-PET/MR) in predicting left ventricular (LV) wall motion recovery after percutaneous revascularisation of coronary chronic total occlusion (CTO). Methods and results Forty-nine patients with CTO and corresponding wall motion abnormality (WMA) underwent [18F]FDG-PET/MR imaging for viability assessment prior to percutaneous revascularisation. After 3–6 months, 23 patients underwent follow-up MR to evaluate wall motion recovery. In total, 124 segments were assigned to the CTO territories, while 80 segments displayed impaired wall motion. Of these, 68% (54) were concordantly viable in PET and MR; conversely, only 2 segments (2%) were assessed non-viable by both modalities. However, 30% showed a discordant viability pattern, either PET non-viable/MR viable (3 segments, 4%) or PET viable/MR non-viable (21 segments, 26%), and the latter revealed a significant wall motion improvement at follow-up (p = 0.033). Combined imaging by [18F]FDG-PET/MR showed a fair accuracy in predicting myocardial recovery after CTO revascularisation (PET/MR area under ROC curve (AUC) = 0.72, p = 0.002), which was superior to LGE-MR (AUC = 0.66) and [18F]FDG-PET (AUC = 0.58) alone. Conclusion Hybrid PET/MR imaging prior to CTO revascularisation predicts more accurately the recovery of dysfunctional myocardium than PET or MR alone. Its complementary information may identify regions of viable myocardium with increased potential for functional recovery.

P4737Complete surgical revascularization: the impact of the different definitions on mortality

Introduction The concept of complete revascularization arises from the early stages on coronary artery bypass grafting (CABG). There are several different definitions applied across the literature, promoting a difficult comparison between studies. Despite the established importance of complete revascularization, there is no agreement which definition has the most impact on mortality. Objectives Evaluate the impact of the different definitions of complete surgical revascularization in late mortality. Methods Single center retrospective study of all consecutive patients submitted to isolated CABG with previous myocardial viability assessment (myocardial perfusion scintigraphy) from 2011 to 2016. Exclusion criteria: emergent procedures and previous cardiac surgery. The primary end-point was follow-up mortality (n=20). The population of study was162 patients with 22,2% female gender and a mean age of 66 years. The follow-up was complete in 98,8%, median time of 4,1 (IQR 3,0–5,5) years. The completeness of revascularization was classified in all patients according to four different definitions (n=162 for each definition): Numerical (the number of stenotic vessels must equal the number of distal anastomoses applied); Functional (all ischemic myocardial territories are reperfused; areas of old infarction with no viable myocardium are not required to be reperfused); Anatomical Conditional (all stenotic main-branch vessels are revascularized) and Anatomical Unconditional (all stenotic vessels are revascularized, irrespective of size and territory supplied). For each definition, statistical analysis was performed using the Kaplan-Meier method with log rank test and Cox proportional analysis (EuroSCORE II and revascularization definition). Results On univariate analysis, there was no significant statistical association between each definition of complete revascularization and follow-up mortality: numerical (p=0,694); anatomical unconditional (p=0,294); but a trend was found on functional (p=0,063) and anatomical conditional (p=0,084). On multivariate analysis, incomplete functional revascularization increased the risk of follow-up mortality in 2,89 folds and anatomical conditional in 3,28 folds (Figure 1). The other definitions were not statistically associated with late mortality. Conclusion According to this study, complete functional and anatomical conditional revascularization definitions are determinants of follow-up mortality in a multivariate model including EuroScore II. The revascularization of all stenotic main-branch vessels (anatomical conditional) seems to have the highest impact, fact that we should be taken in consideration on daily work.