Search

Background Myocardial infarction (MI) causes contractile dysfunction in the affected tissue, which can be assessed by using DENSE (Displacement ENcoding with Stimulated Echoes) to quantify myocardial strain[1,2]. The aim of this study was to investigate changes in strain revealed by DENSE between the occurrence of MI and a 6 month follow-up, and the relationships with other clinical measures. Methods 50 male patients (age 56 ± 10 years) underwent CMR on a 1.5T Siemens Avanto within 7 days of MI, and 47 returned for a follow-up scan after 6 months. The protocol included cine, DENSE (2D) and late gadolinium enhancement (LGE) imaging. Cine images were used to assess cardiac function by calculating LV ejection fraction (LVEF) and end-systolic volume (LVESV). DENSE and LGE were compared using a single mid-ventricular short-axis slice, which was analysed both as a whole slice and after division into 6 AHA segments. The percentage of each segment which contained LGE was calculated using a threshold of mean +5SD of remote myocardium intensity. DENSE images were analysed to obtain a value for peak circumferential strain (Ecc). Segments in the baseline scans were grouped according to the extent of LGE (non-infarcted, 50% infarcted), and the change in peak Ecc between baseline and follow-up was evaluated using a oneway ANOVA with Tukey’s post-hoc test. Individual patients were compared directly, and the correlations between change in strain and (i) change in LGE (segments) and (ii) change in cardiac function (slices) were assessed. Results Diagnostic images were obtained for 50 patients at baseline, and for 43 patients at follow-up. The results of the group comparisons and the individual patient comparisons are illustrated in Figure 1 and Figure 2 respectively. Conclusions Strain recovery was disclosed by DENSE in infarcted tissue at 6 months post-MI. An increase in peak Ecc at follow-up is associated with a reduction in LGE, and improvement in

Background T1 and T2 cardiac magnetic resonance (CMR) mapping methods have shown promise for infarct characterisation in patients with acute ST-elevation myocardial infarction (STEMI). Non-ST elevation MI is typically a sub-acute problem with infarct characteristics that are less readily defined. We prospectively studied the diagnostic accuracy of two novel (T1, T2 mapping) and one established (T2 STIR) CMR methods for imaging the ischaemic area-at-risk (AAR) in patients with a recent NSTEMI. Methods NSTEMI patients underwent contrast-enhanced CMR at 3.0 Tesla (T) after percutaneous coronary intervention. The presence/extent of infarction was assessed with late gadolinium enhancement imaging (Gadovist, 0.1 mmol/kg). The infarct-related territory (IRA) was identified independently using a combination of angiographic, ECG and clinical findings. AAR was assessed with T1, T2 and T2 STIR methods by 2 observers who were blind to all of the clinical data. Comparisons were made between CMR and clinical findings. Results Seventy-three NSTEMI patients (mean age 57 ± 10 yrs, 78% male) underwent 3.0 T MRI. The mean infarct size was 5.5 ± 7.2% of left ventricular (LV) volume. The AAR T1 and T2 times were 1323 ± 68 ms and 57 ± 5 ms, respectively. The extent of AAR (% of LV volume) estimated with T1 (15.8 ± 10.6%) and T2 maps (16.0 ± 11.8%) was similar (p = 0.838), and moderately well correlated (r = 0.82, p Mean AAR estimated with T2 STIR (7.8 ± 11.6%) was lower than that estimated with T1 (p The IRA was correctly identified in 52 patients (71%) when with T1 CMR, 56 (77%) with T2 CMR, and 32 (44%) with T2 STIR CMR. The diagnostic accuracies of T1 and T2 CMR for identification of the IRA were similar (p = 0.125) whereas T1 CMR and T2 CMR had higher diagnostic accuracy vs. T2 STIR (both p Conclusion T1 and T2 maps have higher diagnostic accuracy than T2 STIR maps, implying superior clinical utility with T1 and T2 CMR for infarct characterisation in NSTEMI patients.

Introduction In primary percutaneous coronary intervention (PCI) for ST elevation myocardial infarction (STEMI), no-reflow after stenting may cause heart failure acutely and in the longer term. Currently there are no evidence-based treatments for no-reflow. We hypothesised that after initial myocardial reperfusion, deferring stent implantation for a limited period of time might reduce no-reflow and its sequelae compared to usual care with immediate stenting. Methods A prospective randomised controlled trial in consecutive STEMI patients (NCT01717573). Patients with risk factors for no-reflow (eg, occluded artery (TIMI 0/1), heavy thrombus burden (TIMI 2+ thrombus grade)) were eligible if TIMI 3 coronary flow had been established by initial aspiration thrombectomy and/or balloon angioplasty. Randomisation was performed electronically to deferred stenting (4–16 h later) or usual care with immediate stenting. Deferred patients received intravenous tirofiban and subcutaneous enoxaparin during the period between randomisation and stenting. All patients received oral dual antiplatelet therapy. The primary end-point was the incidence of no-reflow, defined as the occurrence of TIMI 0/1 flow post stenting. Contrast-enhanced cardiac MRI was performed 2 days post-MI and all patients had prospective follow-up. The angiograms and clinical events were independently adjudicated. Results Of 451 consecutive STEMI patients treated in our centre (11 March–22 November 2012), 101 patients (mean±SD age 60±12 years; 69% male, 13% diabetes, 7% previous MI) were randomised (n=52 to deferred stenting, n=49 immediate stenting). The clinical characteristics were similar in each group. In the deferred stent group, the median (IQR) time to deferred stenting was 8 (6, 11) hours. Compared with usual care with immediate stenting, no-reflow was significantly less frequent in the deferred stenting group: 0.0% versus 10% (p=0.005). Intra-procedural thrombotic events (IPTEs) were also less frequent with deferred stenting: 14% versus 41% (p=0.003). Contrast-enhanced MRI disclosed microvascular obstruction in 59% of patients in the immediate stenting group and 44% in the deferred stenting group (p=0.36). Killip class III heart failure occurred in two patients in the deferred stent group and in one patient in the immediately stented group. Recurrent MI Conclusions For the first time we have found that a strategy of deferred stenting in selected patients reduced no-reflow and IPTEs in primary PCI. Our intervention is pragmatic and potentially widely applicable. Our results support the rationale for a multicentre trial to assess the safety and cost-effectiveness of deferred stenting in primary PCI.

The jeopardised ischaemic area-at-risk (AAR) is a key prognostic determinant in acute myocardial infarction. Myocardial oedema imaging with T2-weighted cardiac magnetic resonance CMR is validated for imaging the AAR and T2 ‘mapping’ is a new method for AAR imaging with clinical and research potential. We aimed to develop an automated post-processing method that would enable straightforward volumetric quantification of AAR with T2 maps. Our approach retains user input (i.e. clinical judgement) to confirm the presence of oedema on an image which is then subjected to an automated analysis. The new method was tested on 12 acute MI patients who had a CMR within 48 hours of hospital admission. Manual segmentation of the left ventricular wall and oedema were available for comparison. Left ventricular wall boundaries were delineated automatically by variational level set methods followed by automated detection of myocardial oedema by fitting a Gaussian-Gaussian mixture statistical model. The mean perpendicular distances between automatically detected left ventricular boundaries and corresponding manual delineated boundaries were 1.8±0.2mm for endocardial boundaries and 2.3±0.3mm for endocardial boundaries. Dice similarity coefficients for agreement (0=no agreement, 1=perfect agreement) between manual delineation and automated segmentation of the left ventricular wall boundaries and oedema regions were 0.85±0.02 and 0.74±0.05, respectively. Compared to standard manual approaches, the new semi-automated method for estimating myocardial oedema is straightforward and accurate.

ObjectivesThe aim of this study was to investigate whether late gadolinium enhancement (LGE) magnetic resonance imaging or N-terminal pro–B-type natriuretic peptide (NT-proBNP) could identify patients with a low risk of death or use of implantable cardioverter-defibrillator (ICD) in patients receiving a primary prevention ICD.BackgroundICDs reduce mortality in patients with heart failure (HF), although two-thirds may never use their device. Current risk stratification, based on New York Heart Association functional class and left ventricular ejection fraction, still leads to implantation of ICDs in patients who may never need their device.MethodsWe examined 157 patients with HF (61 with ischemic cardiomyopathy and 96 with dilated cardiomyopathy; mean age 50.5 years; 78% male) who underwent primary prevention defibrillator implantation. Presence and volume of LGE was measured before device implantation, and serum NT-proBNP level was measured before ICD implantation. The combined primary endpoint was cardiovascular death or appropriate ICD therapy (either appropriate shock or antitachycardia pacing).ResultsThe primary outcome occurred in 32 patients (20.4%) over a median follow-up period of 915 days. Percentage of LGE (hazard ratio [HR]: per 1% increase: 1.06; 95% confidence interval [CI]: 1.04 to 1.09; p < 0.001) and (ln) NT-proBNP (HR: 1.44; 95% CI: 1.04 to 1.98; p = 0.027) were predictors of death or appropriate ICD activation and remained significant when entered into multivariable analysis. When the cohort was stratified into tertiles based on LGE percentage and NT-proBNP, we were able to identify a low-risk group (event rate 3% per year, compared with the intermediate- and high-risk groups [6% and 10% per year, respectively]).ConclusionsBoth percentage of LGE and NT-proBNP were associated with higher risk of death or appropriate ICD activation. The use of these markers in combination may be useful in identifying individuals most likely to benefit from this costly intervention, and more specifically, in the identification of a group at lower risk in whom ICD implantation may be deferred.

In the Randomized Trial of Preventive Angioplasty in Myocardial Infarction (PRAMI; [ISRCTN73028481][1]), compared with infarct-related artery (IRA)-only PCI, additional immediate multivessel PCI (MV-PCI) of non-IRA improved long term prognosis. We studied left ventricular (LV) outcomes in a pre

Background In the Randomised Trial of Preventive Angioplasty in Myocardial Infarction (PRAMI; ISRCTN73028481), compared with infarct-related artery (IRA)-only PCI, additional immediate multivessel PCI (MV-PCI) of non-IRA lesions in patients with acute ST elevation myocardial infarction (STEMI) and multivessel coronary disease (MVD) improved long term prognosis. We studied left ventricular (LV) outcomes in a pre-specified cardiac magnetic resonance (CMR) sub-study. Methods In a single centre prospective sub-study, PRAMI participants were invited to undergo CMR at 1.5 Tesla 1 week and 1 year after primary PCI. LV volumes and function were analysed using semi-automated software by a clinician blinded to treatment group assignment and clinical outcomes. The statistical analyses were performed by an independent statistician. Results Of 465 randomised trial participants in 6 UK hospitals, 138 (30%) were enrolled in Glasgow. Eighty patients (17%) (mean age 60 years, 76% male) underwent CMR initially (n = 41 (51%) in the multi-vessel PCI group; n = 39 (49%) in the IRA-only group). 69 (86%) of these patients had a follow up CMR scan at 1 year (n = 7 lost to follow-up, n = 4 deceased). Mean (and SD) LVEF and volumes at 1 week post-MI and their change at 1 year from baseline were similar (Table 1). Conclusion The CMR sub-study participants represented the majority of all randomised participants in our hospital, which included one third of the PRAMI trial population. Random treatment group assignment in this CMR study was evenly balanced. LV function and volumes were similar at 1 week and 1 year post-intervention in survivors. The CMR sub-study suggests that the benefit of the preventive PCI strategy in PRAMI may not be mediated by any effects on LV function and remodelling. Funding Golden Jubilee National Hospital; PRAMI was funded by Barts and the London Charity.