Predicting Imaging Outcomes in Acute Stroke Therapy—Comparison of Magnetic Resonance Imaging and Computed Tomography

Background: Imaging of acute stroke patients in emergency settings is critical for treatment decisions. Most commonly, CT with CTA is used worldwide for acute stroke. However, MRI may be advantageous in certain settings. With advancements in endovascular clot retrieval techniques, there is a need to identify and use the best possible imaging for the diagnosis and outcome prediction of hyperacute stroke. Methods: This mixed retrospective and prospective observational study was conducted over 2 years in patients who underwent reperfusion therapies. Patients were included in this study if they had a baseline as well as follow-up noncontrast CT and diffusion-weighted imaging (DWI) MRI. We compared them for estimating final infarct size and outcomes after reperfusion therapy. Results: A total of 86 patients were included in the study. Baseline DWI found new infarcts in 33 patients compared to baseline CT. Sensitivity and specificity of CT and DWI in predicting the final infarct size was 75.3% and 76.9% and 97.2% and 92.3%, respectively. A positive correlation of 51.2% and 84.4% was noted between b-CT Alberta stroke programme early CT score (ASPECTS) and b-DWI with 72 hours DWI ASPECTS, respectively (p < 0.001). The positive predictive value of CT was 94.8% and DWI was 98.6%. None of the patients had reversible hyperintensities in the follow-up DWI. Conclusion: MRI is more sensitive and specific than noncontrast CT in predicting final infarct volume. It predicts final outcomes better and could be an alternative if available in acute stroke settings.

Deferred Stenting for Heavy Thrombus Burden During Percutaneous Coronary Intervention for ST-Elevation MI

Patients with ST-elevation MI (STEMI) usually have a huge thrombus burden in the infarct-related artery. Stenting may lead to high chances of the slow-flow/no-reflow phenomenon that leads to periprocedural MI and adverse cardiovascular events. Deferred stenting may be beneficial in this situation as the thrombus burden will reduce, mitigating the slow-flow/no-reflow phenomenon. However, routine deferral of stenting in patients with STEMI has not been found to be beneficial, but when the patient is properly selected, deferred stenting has the potential for reducing the final infarct size. The authors report the safety and feasibility of deferred stenting after 5 days of prolonged anticoagulation in a 45-year-old smoker with STEMI who had a large thrombus load shown on an angiogram. They review the registries, trials and meta-analyses on deferred stenting in the literature and analyse the benefits and harms of the strategy. They also propose an algorithm for applying a strategy for deferred stenting in clinical practice based on the available data.

Myocardial Perfusion Grade by Coronary Angiography can Predict Final Infarct Size and Left Ventricular Function in Patients with ST-elevation Myocardial Infarction Treated with a Pharmaco-invasive Strategy

BACKGROUND: Primary percutaneous coronary intervention (PCI) is the reperfusion strategy of choice in ST-elevation myocardial infarction (STEMI). Transfer for early angioplasty after thrombolytic therapy should be done without delay and has been directly related to improved patients’ outcome compared with thrombolysis alone. TIMI myocardial perfusion (TMP) grade provides important prognostic information for epicardial flow. AIM: We studied the relationship between TMP grade (at the end of the PCI procedure) and left ventricular ejection fraction (LVEF) and infarct size within 1 month in such patients. METHODS: A total of forty patients with diagnosis of STEMI (mean age 57.32 ± 10.44, 33 men) were studied, all patients underwent primary PCI. Grading of myocardial perfusion was done immediately post-PCI. Infarction size, end-diastolic volume (EDV), end-systolic volume (ESV), and LVEF were all measured by myocardial perfusion imaging (Gated single-photon emission computed tomography) within 1 month of STEMI. RESULTS: Final infarct size ranged from 0 to 59 cm (mean =19.18 ± 15.8 cm). EDV ranged from 52 to 228 ml (mean = 128.60 ± 51.01 ml). ESV ranged from 16 to 169 ml (mean =72.05 ± 42.09 ml) and EF ranged from 21% to 72% (mean = 46.0 ± 12.80%). Viable but ischemic myocardial area ranged from 0 to 18 cm (mean =3.38 ± 4.45 cm). There was a significant “negative” correlation between the myocardial perfusion grade and the final infarct size. Furthermore, myocardial perfusion grade was significantly inversely related to EDV and ESV, but directly related to EF. Patients who received thrombolytic therapy had significant lesser perfusion grade than who underwent PCI directly. CONCLUSION: Assessment of the myocardial perfusion grade during PCI is a good prognostic marker about the final infarct size, ESV, EDV, and EF in patients with STEMI treated with a pharmaco-invasive strategy (thrombolytic followed by PCI).

Toward a more inclusive paradigm: thrombectomy for stroke patients with pre-existing disabilities

BackgroundPersons with pre-existing disabilities represent over one-third of acute stroke presentations, but account for a far smaller proportion of those receiving endovascular thrombectomy (EVT) and thrombolysis. This is despite existing ethical, economic, legal, and social directives to maximize equity for this vulnerable population. We sought to determine associations between baseline modified Rankin Scale (mRS) and outcomes after EVT.MethodsIndividuals who underwent EVT were identified from a prospectively maintained database. Demographics, medical history, presentations, treatments, and outcomes were recorded. Baseline disability was defined as baseline mRS≥2. Accumulated disability was defined as the delta between baseline mRS and absolute 90-day mRS.ResultsOf 381 individuals, 49 had baseline disability (five with mRS=4, 23 mRS=3, 21 mRS=2). Those with baseline disability were older (81 vs 68 years, P<0.0001), more likely female (65% vs 49%, P=0.032), had more coronary disease (39% vs 20%, P=0.006), stroke/TIA history (35% vs 15%, P=0.002), and higher NIH Stroke Scale (19 vs 16, P=0.001). Baseline mRS was associated with absolute 90-day mRS ≤2 (OR=0.509, 95%CI=0.370–0.700). However, baseline mRS bore no association with accumulated disability by delta mRS ≤0 (ie, return to baseline, OR=1.247, 95%CI=0.943–1.648), delta mRS ≤1 (OR=1.149, 95%CI=0.906–1.458), delta mRS ≤2 (OR 1.097, 95% CI 0.869–1.386), TICI 2b–3 reperfusion (OR=0.914, 95%CI=0.712–1.173), final infarct size (P=0.853, β=−0.014), or intracerebral hemorrhage (OR=0.521, 95%CI=0.244–1.112).ConclusionsWhile baseline mRS was associated with absolute 90-day disability, there was no association with accumulated disability or other outcomes. Patients with baseline disability should not be routinely excluded from EVT based on baseline mRS alone.

Hyper-acute cardiovascular magnetic resonance T1 mapping predicts infarct characteristics in patients with ST elevation myocardial infarction

Background Myocardial recovery after primary percutaneous coronary intervention in acute myocardial infarction is variable and the extent and severity of injury are difficult to predict. We sought to investigate the role of cardiovascular magnetic resonance T1 mapping in the determination of myocardial injury very early after treatment of ST-segment elevation myocardial infarction (STEMI). Methods STEMI patients underwent 3 T cardiovascular magnetic resonance (CMR), within 3 h of primary percutaneous intervention (PPCI). T1 mapping determined the extent (area-at-risk as %left ventricle, AAR) and severity (average T1 values of AAR) of acute myocardial injury, and related these to late gadolinium enhancement (LGE), and microvascular obstruction (MVO). The characteristics of myocardial injury within 3 h was compared with changes at 24-h to predict final infarct size. Results Forty patients were included in this study. Patients with average T1 values of AAR ≥1400 ms within 3 h of PPCI had larger LGE at 24-h (33% ±14 vs. 18% ±10, P = 0.003) and at 6-months (27% ±9 vs. 12% ±9; P < 0.001), higher incidence and larger extent of MVO (85% vs. 40%, P = 0.016) & [4.0 (0.5–9.5)% vs. 0 (0–3.0)%, P = 0.025]. The average T1 value was an independent predictor of acute LGE (β 0.61, 95%CI 0.13 to 1.09; P = 0.015), extent of MVO (β 0.22, 95%CI 0.03 to 0.41, P = 0.028) and final infarct size (β 0.63, 95%CI 0.21 to 1.05; P = 0.005). Receiver-operating-characteristic analysis showed that T1 value of AAR obtained within 3-h, but not at 24-h, predicted large infarct size (LGE > 9.5%) with 100% positive predictive value at the optimal cut-off of 1400 ms (area-under-the-curve, AUC 0.88, P = 0.006). Conclusion Hyper-acute T1 values of the AAR (within 3 h post PPCI, but not 24 h) predict a larger extent of MVO and infarct size at both 24 h and 6 months follow-up. Delayed CMR scanning for 24 h could not substitute the significant value of hyper-acute average T1 in determining infarct characteristics.

P4436Impaired myocardial healing in patients with diabetes after ST-Elevation Myocardial Infarction

Background Diabetes mellitus (DM) significantly increases mortality following myocardial infarction (MI). The underlying mechanism explaining this adverse prognosis is not completely understood. Purpose This study sought to investigate the characteristics of myocardial healing after MI in DM patients. Methods 62 recruited ST-elevation myocardial infarction (STEMI) patients (21 with DM and 41 controls) underwent acute (1–3 days post-STEMI) and 6 months (6M) follow-up cardiac magnetic resonance scans (CMR). Control cases were matched for the peak troponin levels and area at risk on the acute CMR scans. Blood samples were obtained 6, 24, 48 hours and 6 months after STEMI. Results Despite similar severity of the initial ischaemic injury, DM patients had lower myocardial salvage index (MSI) and as a result larger final infarct size at 6 months. Further segment-based analysis of the acute CMR scans showed significantly prolonged T1-mapping values in all segments including non-ischaemic myocardium in DM patients and poorer recovery of the late gadolinium enhancement (LGE) of the infarcted segments in that group. Additionally, DM patients had higher monocyte counts 24 hours post-MI (1.2±0.4x109/μl DM vs 0.88±0.3 x109/μl control, p=0.001). We found that HbA1C correlated with monocyte count measured 24 hours after STEMI (r=0.577, p=0.006, n=21). HbA1C also predicted myocardial salvage index (MSI) at 6M post STEMI in the DM patients (r=0.891, p=0.017, n=13). Conclusions DM patients presenting with STEMI have increased peripheral blood monocytosis and larger final infarct size compared with STEMI patients without DM. Poorly controlled DM predisposes to adverse cardiac remodelling after STEMI. Acknowledgement/Funding OHSRC Research Grant, National Institute for Health Research (NIHR), British Heart Foundation Centre of Excellence Oxford

P949Early QW duration, depth and area in prediction of reperfusion success in patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention - a CMR study

Background Pathological Q-wave (QW) in the electrocardiogram (ECG) before primary percutaneous coronary intervention (primary PCI) is a strong prognostic marker in patients with ST-segment elevation myocardial infarction (STEMI). However, current QW criteria are either not clinical applicable or have a lack of diagnostic performance. Furthermore, the term “pathological” QW is debatable given that even patients with large pathological QW do have substantial myocardial salvage index. Accordingly, we evaluated the association between QW duration, depth, area (QW morphology) and non-viable myocardium, myocardial salvage index as well as microvascular obstruction (myocardial salvage index and microvascular obstruction are considered reperfusion success) using cardiac magnetic resonance imaging (CMR). Methods A total of 516 patients with their first STEMI had obtained an ECG before primary PCI and an additional CMR performed acute at day 1 (interquartile range [IQR], 1–1) and at follow-up at day 92 (IQR, 89–96). The largest measurable QW in ECG was used for analysis of QW morphology. A new QW criteria (Copenhagen QW criteria) composite of duration and depth as well as a new QW area criteria were made using ROC-analysis, and were compared with modified Minnesota criteria. Results The QW morphology was strongly associated to all CMR endpoints (p≤0.0001) and showed a strong linear correlation with final infarct size, final transmurality and final myocardial salvage index (p≤0.0001). The diagnostic performance of QW morphology, Copenhagen QW criteria and QW area criteria was over-all comparable to the modified Minnesota criteria in prediction of non-viable myocardium. Conclusion QW morphology in STEMI patients has a strong linear association with reperfusion success. The larger final infarct size, final transmurality or lower final myocardial salvage index the larger QW morphology. Hence, it is suggested that the term pathological is not used as a dichotomous condition in patients with STEMI but rather evaluated on the basis of extent. Acknowledgement/Funding Rigshospital Research Fund

P3096The cardioprotective effect of FFR-significant multivessel disease detected by cardiac magnetic resonance imaging in patients following ST-segment elevation myocardial infarction. Results from DANAMI3

Background In patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI), reperfusion injury accounts for a significant part of the final infarct size, which is directly related to patient prognosis. In animal studies brief periods of ischemia in non-infarct related coronary arteries protects the myocardium via remote ischemic perconditioning. Fractional flow reserve (FFR) measures functional significant coronary stenosis which may offer remote ischemic perconditioning of the myocardium. It has not previously been investigated if FFR-significant stenosis in non-culprit myocardium offers cardioprotection following STEMI. Purpose To investigate cardioprotective effect of FFR-significant multivessel disease (MVD) on final infarct size and myocardial salvage in a large contemporary cohort of patients with ST-segment elevation myocardial infarction (STEMI). Methods and results We included 509 patients with STEMI from the DANAMI-3 trial, divided into three groups: 388 (76%) patients had single vessel disease (SVD), 34 (7%) had non-FFR-significant MVD and 192 (17%) had FFR-significant MVD. CMR was performed at baseline and three months after primary PCI. There was no difference in final infarct size; mean infarct size (% left ventricular mass) SVD 9±3%; non-FFR-significant MVD 9±3%; and FFR-significant MVD 9±3%, p=0.95, or in myocardial salvage index (MSI) between groups, calculated as (area-at-risk – infarct size)/area-at-risk; mean index (%) SVD 67±23%; non-FFR-significant MVD 68±19%; and FFR-significant MVD 67±21%, p=0,99. In multivariable regression analyses FFR-significant MVD was not associated med larger MSI (p=0.84) or lower infarct size (p=0.60). Figure 1. A. Late gadolinium (LGE) cardiac magnetic resonance (CMR) image of a mid-ventricular short-axis slice. Hyperintense signals (arrow) shows contrast enhancement in the anterior-septal segments, indicating myocardial infarction (MI). B. Same patient. T2-weighted image of the same mid-ventricular short-axis slice. Hyperintense signals (arrows) shows edema in the anterior-septal segments. Conclusions FFR-significant functional MVD of non-culprit myocardium does not offer cardioprotection in patients following STEMI.

Cangrelor versus Ticagrelor in Patients Treated with Primary Percutaneous Coronary Intervention: Impact on Platelet Activity, Myocardial Microvascular Function and Infarct Size: A Randomized Controlled Trial

Background Oral P2Y12 inhibitors take more than 2 hours to achieve full effect in healthy subjects and this action is further delayed in patients with acute myocardial infarction. Intravenous P2Y12 inhibition might lead to more timely and potent anti-platelet effect in the context of emergency primary angioplasty, improving myocardial recovery. Objectives This article compares the efficacy of intravenous cangrelor versus ticagrelor in a ST-elevation myocardial infarction (STEMI) population treated with primary percutaneous coronary intervention (PPCI). Materials and Methods In an open-label, prospective, randomized controlled trial, 100 subjects with STEMI were assigned 1:1 to intravenous cangrelor or oral ticagrelor. The co-primary endpoints were platelet P2Y12 inhibition at infarct vessel balloon inflation time, 4 and 24 hours. Secondary endpoints included indices of coronary microcirculatory function: index of microvascular resistance (IMR), initial infarct size (troponin at 24 hours) and final infarct size at 12 weeks (cardiac magnetic resonance). Secondary endpoints included indices of coronary microcirculatory function (index of microvascular resistance [IMR]), initial infarct size (troponin at 24 hours), final infarct size at 12 weeks (cardiac magnetic resonance), corrected thrombolysis in myocardial infarction (TIMI) frame count, TIMI flow grade, myocardial perfusion grade, and ST-segment resolution (ClinicalTrials.gov NCT02733341). Results P2Y12 inhibition at first balloon inflation time was significantly greater in cangrelor-treated patients (cangrelor P2Y12 reaction unit [PRU] 145.2 ± 50.6 vs. ticagrelor 248.3 ± 55.1). There was no difference in mean PRU at 4 and 24 to 36 hours post-dosing. IMR, final infarct size, angiographic and electrocardiographic measures of reperfusion were all similar between groups. Conclusion Cangrelor produces more potent P2Y12 inhibition at the time of first coronary balloon inflation time compared with ticagrelor. Despite this enhanced P2Y12 inhibition, coronary microvascular function and final infarct size did not differ between groups.