Maria P. Lopez-Lereu

Prognostic value of a comprehensive cardiac magnetic resonance assessment soon after a first ST-segment elevation myocardial infarction.

OBJECTIVES To evaluate the prognostic value of a comprehensive cardiac magnetic resonance (CMR) assessment soon after a first ST-segment elevation myocardial infarction (STEMI). BACKGROUND CMR allows for a simultaneous assessment of wall motion abnormalities (WMA), WMA with low-dose dobutamine (WMA-dobutamine), microvascular obstruction, and transmural necrosis. This approach has been proven to be useful to predict late systolic recovery soon after STEMI. Its prognostic value and the relative prognostic weight of these indexes are not well-defined. METHODS We studied 214 consecutive patients with a first STEMI treated with thrombolytic therapy or primary angioplasty discharged from hospital. In the first week (7 +/- 1 day after infarction), with CMR we determined the extent (number of segments) of WMA, WMA-dobutamine, microvascular obstruction, and transmural necrosis. RESULTS During a median follow-up of 553 days, 21 major adverse cardiac events (MACE) including 4 cardiac deaths, 6 nonfatal myocardial infarctions, and 11 readmissions for heart failure were documented. The MACE was associated with a larger extent of WMA (8 +/- 4 segments vs. 5 +/- 3 segments, p < 0.001), WMA-dobutamine (6 +/- 4 segments vs. 4 +/- 3 segments, p = 0.004), microvascular obstruction (3 +/- 3 segments vs. 1 +/- 2 segments p <0.001), and transmural necrosis (7 +/- 3 segments vs. 3 +/- 3 segments, p < 0.001). In a complete multivariate analysis that included baseline characteristics, electrocardiogram, biomarkers, angiography, ejection fraction, left ventricular volumes, and all CMR indexes, WMA/segment (hazard ratio: 1.29 [95% confidence interval: 1.11 to 1.49], p = 0.001) and the extent of transmural necrosis/segment (hazard ratio: 1.30 [95% confidence interval: 1.12 to 1.51], p < 0.001) were the only independent prognostic variables. CONCLUSIONS A comprehensive CMR assessment is useful for stratifying risk soon after STEMI, but only the extent of systolic dysfunction and of transmural necrosis provide independent prognostic information.

Cardiovascular magnetic resonance-derived intramyocardial hemorrhage after STEMI: Influence on long-term prognosis, adverse left ventricular remodeling and relationship with microvascular obstruction

BACKGROUND T2 weighted cardiovascular magnetic resonance (CMR) can detect intramyocardial hemorrhage (IMH) after ST-elevation myocardial infarction (STEMI). The long-term prognostic value of IMH beyond a comprehensive CMR assessment with late enhancement (LE) imaging including microvascular obstruction (MVO) is unclear. The value of CMR-derived IMH for predicting major adverse cardiac events (MACE) and adverse cardiac remodeling after STEMI and its relationship with MVO was analyzed. METHODS CMR including LE and T2 sequences was performed in 304 patients 1 week after STEMI. Adverse remodeling was defined as dilated left ventricular end-systolic volume indexes (dLVESV) at 6 months CMR. RESULTS During a median follow-up of 140 weeks, 47 MACE (10 cardiac deaths, 16 myocardial infarctions, 21 heart failure episodes) occurred. Predictors of MACE were ejection fraction (HR .95 95% CI [.93-.97], p=.001, per %) and IMH (HR 1.17 95% CI [1.03-1.33], p=.01, per segment). The extent of MVO and IMH significantly correlated (r=.951, p<.0001). dLVESV was present in 40% of patients. CMR predictors of dLVESV were: LVESV (OR 1.11 95% CI [1.07-1.15], p<.0001, per ml/m(2)), infarct size (OR 1.05 95% CI [1.01-1.09], p=.02, per %) and IMH (OR 1.54 95% CI [1.15-2.07], p=.004, per segment). Addition of T2 information did not improve the LE and cine CMR-model for predicting MACE (.744 95% CI [.659-.829] vs. .734 95% CI [.650-.818], p=.6) or dLVESV (.914 95% CI [.875-.952] vs. .913 95% CI [.875-.952], p=.9). CONCLUSIONS IMH after STEMI predicts MACE and adverse remodeling. Nevertheless, with a strong interrelation with MVO, the addition of T2 imaging does not improve the predictive value of LE-CMR.

Prognostic and therapeutic implications of dipyridamole stress cardiovascular magnetic resonance on the basis of the ischaemic cascade

Objective: To determine the prognostic and therapeutic implications of stress perfusion cardiovascular magnetic resonance (CMR) on the basis of the ischaemic cascade. Setting: Single centre study in a teaching hospital in Spain. Patients: Dipyridamole stress CMR was performed on 601 patients with ischaemic chest pain and known or suspected coronary artery disease. On the basis of the ischaemic cascade, patients were categorised in C1 (no evidence of ischaemia, n = 354), C2 (isolated perfusion deficit at stress first-pass perfusion imaging, n = 181) and C3 (simultaneous perfusion deficit and inducible wall motion abnormalities, n = 66). CMR-related revascularisation (n = 102, 17%) was defined as the procedure prompted by the CMR results and carried out within the next three months. Results: During a median follow-up of 553 days, 69 major adverse cardiac events (MACE), including 21 cardiac deaths, 14 non-fatal myocardial infarctions and 34 admissions for unstable angina with documented abnormal angiography were detected. In non-revascularised patients (n = 499), the MACE rate was 4% (14/340) in C1, 20% (26/128) in C2 and 39% (12/31) in C3 (adjusted p value = 0.004 vs C2 and <0.001 vs C1). CMR-related revascularisation had neutral effects in C2 (20% vs 19%, 1.1 (0.5 to 2.4), p = 0.7) but independently reduced the risk of MACE in C3 (39% vs 11%, 0.2 (0.1 to 0.7), p = 0.01). Conclusions: Dypiridamole stress CMR is able to stratify risk on the basis of the ischaemic cascade. A small group of patients with severe ischaemia—simultaneous perfusion deficit and inducible wall motion abnormalities—are at the highest risk and benefit most from MACE reduction due to revascularisation.

Microvascular perfusion 1 week and 6 months after myocardial infarction by first-pass perfusion cardiovascular magnetic resonance imaging

Objective: To characterise the evolution of myocardial perfusion during the first 6 months after myocardial infarction by first-pass perfusion cardiovascular magnetic resonance imaging (CMR) and determine its significance. Design: Prospective cohort design. Setting: Single-centre study in a teaching hospital in Spain. Patients: 40 patients with a first ST-elevation myocardial infarction, single-vessel disease and thrombolysis in myocardial infarction (TIMI) grade 3 flow (stent in 33 patients) underwent rest and low-dose dobutamine CMR 7 (SD 1) and 184 (SD 11) days after infarction. Microvascular perfusion was assessed at rest by visual assessment and quantitative analysis of first-pass perfusion CMR. Of the 640 segments, 290 segments subtended by the infarct-related artery (IRA) were focused on. Results: Both 1 week and 6 months after infarction, segments with normal perfusion showed more wall thickening, contractile reserve and wall thickness, and less transmural necrosis, p <0.05 in all cases. Of 76 hypoperfused segments at the first week, 47 (62%) normalised perfusion at the sixth month. However, 42 segments (14% of the whole group) showed chronic abnormal perfusion; these segments showed worse CMR indices in the late phase (p<0.05 in all cases). Conclusions: In patients with an open IRA, more than half of the segments with abnormal perfusion at the first week are normally perfused after six months. First-pass perfusion CMR shows that in a small percentage of segments, abnormal perfusion may become a chronic phenomenon—these areas have a more severe deterioration of systolic function, wall thickness, contractile reserve and the transmural extent of necrosis.

Contractile Reserve and Extent of Transmural Necrosis in the Setting of Myocardial Stunning: Comparison at Cardiac MR Imaging

PURPOSE To perform a comparison of cardiac magnetic resonance (MR) imaging-derived ejection fraction (EF) during low-dose dobutamine infusion (EF(D)) with the extent of segments with transmural necrosis in more than 50% of their wall thickness (ETN) for the prediction of major adverse cardiac events (MACEs) and late systolic recovery soon after a first ST-segment elevation myocardial infarction (STEMI). MATERIALS AND METHODS Institutional ethics committee approval and written informed consent were obtained. One hundred nineteen consecutive patients with a first STEMI, a depressed left ventricular EF, and an open infarct-related artery underwent MR imaging at 1 week after infarction. EF(D) and ETN (by using a 17-segment model) were determined, and the prediction of MACEs and systolic recovery at follow-up was assessed by using area under the receiver operating characteristic curve (AUC) and multivariable regression analysis. RESULTS During follow-up (median, 613 days; range, 312-1243 days), 18 MACEs (five cardiac deaths, six myocardial infarctions, seven readmissions for heart failure) occurred. MACEs were associated with a lower EF(D) (43% +/- 12 [standard deviation] vs 49% +/- 10, P = .02) and a larger ETN (seven segments +/- three vs four segments +/- three, P < .001). Patients with systolic recovery (increase in EF of >5% at follow-up compared with baseline EF, n = 44) displayed a higher EF(D) (51% +/- 10 vs 47% +/- 9, P = .04) and a smaller ETN (three segments +/- two vs five segments +/- three, P = .002) at 1 week. ETN and EF(D) both related to MACEs (AUC: 0.78 vs 0.67, respectively, P = .1) and systolic recovery (AUC: 0.68 vs 0.62, respectively, P = .3). According to multivariable analysis, ETN was the only MR variable associated with time to MACEs (hazard ratio, 1.38; 95% confidence interval: 1.19, 1.60; P < .001) and systolic recovery (odds ratio, 0.76; 95% confidence interval: 0.64, 0.92; P = .004) independent of baseline characteristics. CONCLUSION ETN is as useful as EF(D) for the prediction of MACEs and systolic recovery soon after STEMI.

Right ventricular involvement in anterior myocardial infarction: a translational approach

AIMS The aim of the present study was to evaluate the involvement of the right ventricle (RV) in reperfused anterior ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS Left anterior descending (LAD)-perfused area (using thioflavin-S staining after selective infusion in proximal LAD artery, %), infarct size (using triphenyltetrazolium chloride staining, %), and salvaged myocardium (% of LAD-perfused area) in the right and left ventricle (LV) were quantified in a 90-min LAD occlusion 3-day reperfusion model in swine (n = 8). Additionally, we studied, using cardiovascular magnetic resonance, 20 patients with a first STEMI due to proximal LAD occlusion treated with primary angioplasty. Area at risk (T2-weighted sequence, %), infarct size (late enhancement imaging, %), and salvaged myocardium (% of area at risk) in the right and LV were quantified. In swine, a large LAD-perfused area was detected both in the right and LV (30 +/- 5 vs. 62 +/- 15%, P< 0.001) but more salvaged myocardium (94 +/- 6 vs. 73 +/- 11%, P< 0.001) resulted in a smaller right ventricular infarct size (2 +/- 1 vs. 16 +/- 5%, P< 0.001). Similarly, in patients a large area at risk was detected both in the right and LV (34 +/- 13 vs. 43 +/- 12%, P = 0.02). More salvaged myocardium (94 +/- 10 vs. 33 +/- 26%, P < 0.001) resulted in a smaller infarct size (2 +/- 3 vs. 30 +/- 16%, P< 0.001) in the RV. CONCLUSION In reperfused extensive anterior STEMI, a large area of the RV is at risk but the resultant infarct size is small.

Prognostic implications of dipyridamole cardiac MR imaging: a prospective multicenter registry.

PURPOSE To evaluate dipyridamole cardiac magnetic resonance (MR) imaging in the prediction of major events (MEs) in patients with ischemic chest pain in a large multicenter registry. MATERIALS AND METHODS Institutional ethics committee approval and written informed consent were obtained. A total of 1722 patients who were undergoing cardiac MR imaging for chest pain were included. Wall motion abnormalities (WMAs) at rest, hyperemia perfusion defect (PD), late gadolinium enhancement (LGE), and inducible WMA were analyzed (abnormal if more than one abnormal segment was seen) with the 17-segment model. A cardiac MR categorization was created: category 1, no PD, LGE, or inducible WMA; category 2, PD without LGE and inducible WMA; category 3, LGE without inducible WMA; and category 4, inducible WMA. The association with ME was analyzed by using Cox proportional hazard regression multivariate models. RESULTS During a median follow-up period of 308 days, 61 MEs (4%) occurred (36 cardiac deaths, 25 nonfatal myocardial infarctions). MEs were associated with a greater extent of WMA, PD, LGE, and inducible WMA (P ≤ .001 for all analyses). In multivariable analyses, PD (P = .002) and inducible WMA (P = .0001) were the only cardiac MR predictors. ME rate in categories 1, 2, 3, and 4 was 2% (14 of 901 patients), 3% (six of 219 patients), 4% (15 of 409 patients), and 14% (26 of 193 patients), respectively (category 4 vs category 1, adjusted P < .001). Cardiac MR-directed revascularization was performed in 242 patients (14%) and reduced the risk of ME in only category 4 (7% [six of 92 patients] vs 26% [26 of 101 patients], P = .0004). CONCLUSION Dipyridamole cardiac MR imaging can be used to predict MEs in patients with ischemic chest pain. Patients with inducible WMA are at the highest risk for MEs and benefit the most from revascularization.

Resultados de la estrategia farmacoinvasiva y de la angioplastia primaria en la reperfusión del infarto con elevación del segmento ST. Estudio con resonancia magnética cardiaca en la primera semana y en el sexto mes

INTRODUCTION AND OBJECTIVES Pharmacoinvasive strategy represents an attractive alternative to primary angioplasty. Using cardiovascular magnetic resonance imaging we compared the left ventricular outcome of the pharmacoinvasive strategy and primary angioplasty for the reperfusion of ST-segment elevation myocardial infarction. METHODS Cardiovascular magnetic resonance was performed 1 week and 6 months after infarction in two consecutive cohorts of patients included in a prospective university hospital ST-segment elevation myocardial infarction registry. During the period 2004-2006, 151 patients were treated with pharmacoinvasive strategy (thrombolysis followed by routine non-immediate angioplasty). During the period 2007-2008, 93 patients were treated with primary angioplasty. A propensity score matched population was also evaluated. RESULTS At 1-week cardiovascular magnetic resonance, pharmacoinvasive strategy and primary angioplasty patients showed a similar extent of area at risk (29±15 vs. 29±17%, P=.9). Non-significant differences were detected by cardiovascular magnetic resonance at 1 week and at 6 months in infarct size, salvaged myocardium, microvascular obstruction, ejection fraction, end-diastolic volume index and end-systolic volume index (P>.2 in all cases). The same trend was observed in 1-to-1 propensity score matched patients. The rate of major adverse cardiac events (death and/or re-infarction) at 1 year was 6% in pharmacoinvasive strategy and 7% in primary angioplasty patients (P=.7). CONCLUSIONS A pharmacoinvasive strategy including thrombolysis and routine non-immediate angioplasty represents a widely available and logistically attractive approach that yields identical short-term and long-term cardiovascular magnetic resonance-derived left ventricular outcome compared to primary angioplasty.

Effect of ischemic postconditioning on microvascular obstruction in reperfused myocardial infarction. Results of a randomized study in patients and of an experimental model in swine.

BACKGROUND Ischemic postconditioning (PCON) appears as a potentially beneficial tool in ST-segment elevation myocardial infarction (STEMI). We evaluated the effect of PCON on microvascular obstruction (MVO) in STEMI patients and in an experimental swine model. METHODS A prospective randomized study in patients and an experimental study in swine were carried out in two university hospitals in Spain. 101 consecutive STEMI patients were randomized to undergo primary angioplasty followed by PCON or primary angioplasty alone (non-PCON). Using late gadolinium enhancement cardiovascular magnetic resonance, infarct size and MVO were quantified (% of left ventricular mass). In swine, using an angioplasty balloon-induced anterior STEMI model, MVO was defined as the % of area at risk without thioflavin-S staining. RESULTS In patients, PCON (n=49) in comparison with non-PCON (n=52) did not significantly reduce MVO (0 [0-1.02]% vs. 0 [0-2.1]% p=0.2) or IS (18 ± 13% vs. 21 ± 14%, p=0.2). MVO (>1 segment in the 17-segment model) occurred in 12/49 (25%) PCON and in 18/52 (35%) non-PCON patients, p=0.3. No significant differences were observed between PCON and non-PCON patients in left ventricular volumes, ejection fraction or the extent of hemorrhage. In the swine model, MVO occurred in 4/6 (67%) PCON and in 4/6 (67%) non-PCON pigs, p=0.9. The extent of MVO (10 ± 7% vs. 10 ± 8%, p=0.9) and infarct size (23 ± 14% vs. 24 ± 10%, p=0.8) was not reduced in PCON compared with non-PCON pigs. CONCLUSIONS Ischemic postconditioning does not significantly reduce microvascular obstruction in ST-segment elevation myocardial infarction. Clinical Trial Registration http://www.clinicaltrials.gov. Unique identifier: NCT01898546.

Long-term Prognostic Value of a Comprehensive Assessment of Cardiac Magnetic Resonance Indexes After an ST-segment Elevation Myocardial Infarction

INTRODUCTION AND OBJECTIVES A variety of cardiac magnetic resonance indexes predict mid-term prognosis in ST-segment elevation myocardial infarction patients. The extent of transmural necrosis permits simple and accurate prediction of systolic recovery. However, its long-term prognostic value beyond a comprehensive clinical and cardiac magnetic resonance evaluation is unknown. We hypothesized that a simple semiquantitative assessment of the extent of transmural necrosis is the best resonance index to predict long-term outcome soon after a first ST-segment elevation myocardial infarction. METHODS One week after a first ST-segment elevation myocardial infarction we carried out a comprehensive quantification of several resonance parameters in 206 consecutive patients. A semiquantitative assessment (altered number of segments in the 17-segment model) of edema, baseline and post-dobutamine wall motion abnormalities, first pass perfusion, microvascular obstruction, and the extent of transmural necrosis was also performed. RESULTS During follow-up (median 51 months), 29 patients suffered a major adverse cardiac event (8 cardiac deaths, 11 nonfatal myocardial infarctions, and 10 readmissions for heart failure). Major cardiac events were associated with more severely altered quantitative and semiquantitative resonance indexes. After a comprehensive multivariate adjustment, the extent of transmural necrosis was the only resonance index independently related to the major cardiac event rate (hazard ratio=1.34 [1.19-1.51] per each additional segment displaying>50% transmural necrosis, P<.001). CONCLUSIONS A simple and non-time consuming semiquantitative analysis of the extent of transmural necrosis is the most powerful cardiac magnetic resonance index to predict long-term outcome soon after a first ST-segment elevation myocardial infarction.