The significance of persistent ST elevation versus early resolution of ST segment elevation after primary PTCA

Role of ST-Segment Resolution Alone and in Combination With TIMI Flow After Primary Percutaneous Coronary Intervention for ST-Segment-Elevation Myocardial Infarction

Background To evaluate the role of ST-segment resolution (STR) alone and in combination with Thrombolysis in Myocardial Infarction (TIMI) flow in reperfusion evaluation after primary percutaneous coronary intervention (PPCI) for ST-segment-elevation myocardial infarction by investigating the long-term prognostic impact. Methods and Results From January 2013 through September 2014, we studied 5966 patients with ST-segment-elevation myocardial infarction enrolled in the CAMI (China Acute Myocardial Infarction) registry with available data of STR evaluated at 120 minutes after PPCI. Successful STR included STR ≥50% and complete STR (ST-segment back to the equipotential line). After PPCI, the TIMI flow was assessed. The primary outcome was 2-year all-cause mortality. STR < 50%, STR ≥50%, and complete STR occurred in 20.6%, 64.3%, and 15.1% of patients, respectively. By multivariable analysis, STR ≥50% (5.6%; adjusted hazard ratio [HR], 0.45 [95% CI, 0.36-0.56]) and complete STR (5.1%; adjusted HR, 0.48 [95% CI, 0.34-0.67]) were significantly associated with lower 2-year mortality than STR <50% (11.7%). Successful STR was an independent predictor of 2-year mortality across the spectrum of clinical variables. After combining TIMI flow with STR, different 2-year mortality was observed in subgroups, with the lowest in successful STR and TIMI 3 flow, intermediate when either of these measures was reduced, and highest when both were abnormal. Conclusions Post-PPCI STR is a robust long-term prognosticator for ST-segment-elevation myocardial infarction, whereas the integrated analysis of STR plus TIMI flow yields incremental prognostic information beyond either measure alone, supporting it as a convenient and reliable surrogate end point for defining successful PPCI. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01874691.

Residual ST-segment elevation to predict long-term clinical and CMR-derived outcomes in STEMI

Residual ST-segment elevation after ST-segment elevation myocardial infarction (STEMI) has traditionally been considered a predictor of left ventricular (LV) dysfunction and ventricular aneurism. However, the implications in terms of long-term prognosis and cardiac magnetic resonance (CMR)-derived structural consequences are unclear. A total of 488 reperfused STEMI patients were prospectively included. The number of Q wave leads with residual ST-segment elevation > 1 mm (Q-STE) at pre-discharge ECG was assessed. LV ejection fraction (LVEF, %) and infarct size (IS, % of LV mass) were quantified in 319 patients at 6-month CMR. Major adverse cardiac events (MACE) were defined as all-cause death and/or re-admission for acute heart failure (HF), whichever occurred first. During a mean follow-up of 6.1 years, 92 MACE (18.9%), 39 deaths and 53 HF were recorded. After adjustment for baseline characteristics, Q-STE (per lead with > 1 mm) was independently associated with a higher risk of long-term MACE (HR 1.24 [1.07-1.44] per lead, p = 0.004), reduced (< 40%) LVEF (HR 1.36 [1.02-1.82] per lead, p = 0.04) and large (> 30% of LV mass) IS (HR 1.43 [1.11-1.85] per lead, p = 0.006) at 6-month CMR. Patients with Q-STE ≥ 2 leads (n = 172, 35.2%) displayed lower MACE-free survival, more depressed LVEF, and larger IS at 6-month CMR (p < 0.001 for all comparisons). Residual ST-segment elevation after STEMI represents a universally available tool that predicts worse long-term clinical and CMR-derived structural outcomes.

Post-ST-Segment-Elevation Myocardial Infarction Platelet Reactivity Is Associated With the Extent of Microvascular Obstruction and Infarct Size as Determined by Cardiac Magnetic Resonance Imaging

Background

Despite optimized medical management and techniques of primary percutaneous coronary intervention, a substantial proportion of patients with ST‐segment–elevation myocardial infarction (STEMI) display significant microvascular damage. Thrombotic microvascular obstruction (MVO) has been implicated in the pathogenesis of microvascular and subsequent myocardial damage attributed to distal embolization and microvascular platelet plugging. However, there are only scarce data regarding the effect of platelet reactivity on MVO.

Methods and Results

We prospectively evaluated 105 patients in 2 distinct periods (2012–2013 and 2016–2018) who presented with first ST‐segment–elevation myocardial infarction and underwent primary percutaneous coronary intervention. All patients were treated with dual antiplatelet therapy (DAPT). Blood samples were analyzed for platelet reactivity, and cardiac magnetic resonance imaging scans were evaluated for late gadolinium enhancement and MVO. DAPT suboptimal response was defined as hyporesponsiveness to either aspirin or P2Y12 receptor inhibitor agents and demonstrated in 31 patients (29.5%) of the current cohort. Suboptimal platelet response to DAPT was associated with a significantly greater extent of MVO when expressed as a percentage of the left ventricular mass, left ventricular scar, and the number of myocardial left ventricular segments showing MVO (P<0.01 for each). Adjusted multivariable logistic regression model revealed that suboptimal response to DAPT is significantly associated with both greater late gadolinium enhancement (P<0.01) and MVO extent (odds ratio, 3.7 [95% CI, 1.3–10.5]; P=0.01). Patients with a greater extent of MVO were more likely to sustain major adverse cardiovascular events at a 1‐year follow‐up (37% versus 11%; P<0.01).

Conclusions

In patients undergoing primary percutaneous coronary intervention for ST‐segment–elevation myocardial infarction, platelet reactivity in response to DAPT is a key predictor of the extent of both myocardial and microvascular damage.

Assessment of Selected Baseline and Post-PCI Electrocardiographic Parameters as Predictors of Left Ventricular Systolic Dysfunction after a First ST-Segment Elevation Myocardial Infarction

OBJECTIVE

To assess the performance of ten electrocardiographic (ECG) parameters regarding the prediction of left ventricular systolic dysfunction (LVSD) after a first ST-segment-elevation myocardial infarction (STEMI).

METHODS

We analyzed 249 patients (74.7% males) treated with primary percutaneous coronary intervention (PCI) included into a single-center cohort study. We sought associations between baseline and post-PCI ECG parameters and the presence of LVSD (defined as left ventricular ejection fraction [LVEF] ≤ 40% on echocardiography) 6 months after STEMI.

RESULTS

Patients presenting with LVSD (n = 52) had significantly higher values of heart rate, number of leads with ST-segment elevation and pathological Q-waves, as well as total and maximal ST-segment elevation at baseline and directly after PCI compared with patients without LVSD. They also showed a significantly higher prevalence of anterior STEMI and considerably wider QRS complex after PCI, while QRS duration measurement at baseline showed no significant difference. Additionally, patients presenting with LVSD after 6 months showed markedly more severe ischemia on admission, as assessed with the Sclarovsky-Birnbaum ischemia score, smaller reciprocal ST-segment depression at baseline and less profound ST-segment resolution post PCI. In multivariate regression analysis adjusted for demographic, clinical, biochemical and angiographic variables, anterior location of STEMI (OR 17.78; 95% CI 6.45-48.96; p < 0.001), post-PCI QRS duration (OR 1.56; 95% CI 1.22-2.00; p < 0.001) expressed per increments of 10 ms and impaired post-PCI flow in the infarct-related artery (IRA; TIMI 3 vs. <3; OR 0.14; 95% CI 0.04-0.46; p = 0.001) were identified as independent predictors of LVSD (Nagelkerke's pseudo R2 for the logistic regression model = 0.462). Similarly, in multiple regression analysis, anterior location of STEMI, wider post-PCI QRS, higher baseline number of pathological Q-waves and a higher baseline Sclarovsky-Birnbaum ischemia score, together with impaired post-PCI flow in the IRA, higher values of body mass index and glucose concentration on admission were independently associated with lower values of LVEF at 6 months (corrected R2 = 0.448; p < 0.00001).

CONCLUSIONS

According to our study, baseline and post-PCI ECG parameters are of modest value for the prediction of LVSD occurrence 6 months after a first STEMI.

Accuracy of Post-thrombolysis ST-segment Reduction as an Adequate Reperfusion Predictor in the Pharmaco-Invasive Approach

Fundamento

A intervenção coronária percutânea primária é considerada o “padrão-ouro” para reperfusão coronária. Entretanto, quando não disponível, a estratégia fármaco-invasiva é método alternativo, e o eletrocardiograma (ECG) tem sido utilizado para identificar sucesso na reperfusão.

Objetivos

Nosso estudo teve como objetivo examinar alterações no segmento-ST pós-lise e seu poder de prever a recanalização, usando os escores angiográficos TIMI e blush miocárdio (MBG) como critério de reperfusão ideal.

Métodos

Foram estudados 2.215 pacientes com infarto agudo do miocárdio com supra-ST submetidos à fibrinólise [(Tenecteplase)-TNK] e encaminhados para angiografia coronária em até 24 h pós-fibrinólise ou imediatamente encaminhados à terapia de resgate. O ECG foi realizado pré-TNK e 60 min-pós. Os pacientes foram categorizados em dois grupos: aqueles com reperfusão ideal (TIMI-3 e MBG-3) e aqueles com reperfusão inadequada (fluxo TIMI <3). Foi definido o critério de reperfusão do ECG pela redução do segmento ST >50%. Consideramos p-valor <0,05 para as análises, com testes bicaudais.

Resultados

O critério de reperfusão pelo ECG apresentou valor preditivo positivo de 56%; valor preditivo negativo de 66%; sensibilidade de 79%; e especificidade de 40%. Houve fraca correlação positiva entre a redução do segmento-ST e os dados angiográficos de reperfusão ideal (r = 0,21; p <0,001) e baixa precisão diagnóstica, com AUC de 0,60 (IC-95%; 0,57-0,62).

Conclusão

Em nossos resultados, a redução do segmento-ST não conseguiu identificar com precisão os pacientes com reperfusão angiográfica apropriada. Portanto, mesmo pacientes com reperfusão aparentemente bem-sucedida devem ser encaminhados à angiografia brevemente, a fim de garantir fluxo coronário macro e microvascular adequados.

Primary percutaneous coronary intervention is appropriate in transient ST-elevation myocardial infarction

INTRODUCTION

Reperfusion therapy by primary percutaneous coronary intervention (PPCI) is generally indicated in patients suffering from acute myocardial infarction (MI) with ST-segment elevation (STEMI). Prior to hospital admission, full ST-segment resolution (fSTR) may occur. Optimal management of such patients with transient STEMI (TSTEMI) is potentially challenging. Our aim was to evaluate the hypothesis that in TSTEMI patients, patency of infarct related artery (IRA) is achieved before PPCI, and to compare the outcome of TSTEMI and STEMI patients during a prolonged follow-up.

MATERIAL AND METHODS

Three hundred consecutive adult STEMI patients were referred to catheterization laboratory. In all patients, standard 12 lead ECGs were obtained both at the time of the first medical contact, and on catheterization laboratory admission.

RESULTS

TSTEMI occurred in 20 patients (6.7%). Despite fSTR (isoelectric ST segment), occluded IRA was found in 5 of these patients (25%). Pre-PPCI TIMI flow grade 2 was found in 6 TSTEMI patients (30%). Troponin T value at 24 h after symptom onset was lower in the TSTEMI group (1.8±2.5 mg/L vs. 3.6±3.5 mg/L, P=0.008). These patients also had a lower value of brain natriuretic peptide (156.3±119.5 ng/L vs. 438.5±429.0 ng/L, P<0.001) and higher left ventricular ejection fraction (59.9±6.3% vs. 51.6±10.2%, P<0.001). All patients were followed for a median of 5.6 years during which the overall survival did not differ between the TSTEMI and STEMI groups.

CONCLUSION

Primary PCI is strongly recommended in TSTEMI patients because of a relatively high incidence of occluded infarct related arteries. The rate of patients with TSTEMI is relatively low.

Role of ST-Segment Resolution in Patients With ST-Segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention (from the 5-Year Outcomes of the EXAMINATION [Evaluation of the Xience-V Stent in Acute Myocardial Infarction] Trial)

In patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI), lack of ST-segment resolution (STR) is associated with poor prognosis at short- and long-term follow-up. The aim of this study was to evaluate the role of STR on very long-term outcomes in patients with STEMI treated with pPCI included in the EXAMINATION (Evaluation of the Xience-V Stent in Acute Myocardial Infarction) trial. Patients were stratified according to the presence of STR < 50% and STR < 70% at the 30-minute post-pPCI electrocardiogram. Primary end point was the patient-oriented composite endpoint (POCE) of all-cause death, any myocardial infarction, or any revascularization at 5-year follow-up. Both baseline and post-PCI 30-minute electrocardiograms were available for STR assessment in 1,351 patients. Of these patients, 228 (16.9%) and 500 (37.0%) exhibited STR < 50% and STR < 70%, respectively. At 5-year follow-up, the POCE was observed more frequently in patients with STR < 50% (hazard ratio [HR] 1.556; 95% confidence interval [CI] 1.194 to 2.027; p <0.001) and in patients with STR < 70% (HR 1.460, 95% CI 1.169 to 1.824, p <0.001) compared with patients with STR > 50% and STR ≥ 70%, respectively. In both cases, this difference was mainly driven by a significant increase in the rate of all-cause death and any revascularization. After multivariable adjustment, STR < 70%, but not STR < 50%, resulted as a 5-year independent predictor of POCE (adjusted HR 1.338, 95% CI 1.008 to 1.778, p = 0.044). In conclusion, in patients with STEMI, the evaluation of 70% STR after pPCI provides independent prognostic information at 5-year follow-up and it can be used to identify patients at high risk of very long-term cardiovascular events.

Incidence and Significance of Spontaneous ST Segment Re-elevation After Reperfused Anterior Acute Myocardial Infarction - Relationship With Infarct Size, Adverse Remodeling, and Events at 1 Year

BACKGROUND

Up to 25% of patients with ST elevation myocardial infarction (STEMI) have ST segment re-elevation after initial regression post-reperfusion and there are few data regarding its prognostic significance.Methods and Results:A standard 12-lead electrocardiogram (ECG) was recorded in 662 patients with anterior STEMI referred for primary percutaneous coronary intervention (PPCI). ECGs were recorded 60-90 min after PPCI and at discharge. ST segment re-elevation was defined as a ≥0.1-mV increase in STMax between the post-PPCI and discharge ECGs. Infarct size (assessed as creatine kinase [CK] peak), echocardiography at baseline and follow-up, and all-cause death and heart failure events at 1 year were assessed. In all, 128 patients (19%) had ST segment re-elevation. There was no difference between patients with and without re-elevation in infarct size (CK peak [mean±SD] 4,231±2,656 vs. 3,993±2,819 IU/L; P=0.402), left ventricular (LV) ejection fraction (50.7±11.6% vs. 52.2±10.8%; P=0.186), LV adverse remodeling (20.1±38.9% vs. 18.3±30.9%; P=0.631), or all-cause mortality and heart failure events (22 [19.8%] vs. 106 [19.2%]; P=0.887) at 1 year.

CONCLUSIONS

Among anterior STEMI patients treated by PPCI, ST segment re-elevation was present in 19% and was not associated with increased infarct size or major adverse events at 1 year.

Outcomes of Patients Presenting With Clinical Indices of Spontaneous Reperfusion in ST-Elevation Acute Coronary Syndrome Undergoing Deferred Angiography

BACKGROUND

Few data are available regarding the optimal management of ST-elevation myocardial infarction patients with clinically defined spontaneous reperfusion (SR). We report on the characteristics and outcomes of patients with SR in the primary percutaneous coronary intervention era, and assess whether immediate reperfusion can be deferred.

METHODS AND RESULTS

Data were drawn from a prospective nationwide survey, ACSIS (Acute Coronary Syndrome Israeli Survey). Definition of SR was predefined as both (1) ≥70% reduction in ST-segment elevation on consecutive ECGs and (2) ≥70% resolution of pain. Of 2361 consecutive ST-elevation-acute coronary syndrome patients in Killip class 1, 405 (17%) were not treated with primary reperfusion therapy because of SR. Intervention in SR patients was performed a median of 26 hours after admission. These patients were compared with the 1956 ST-elevation myocardial infarction patients who underwent primary reperfusion with a median door-to-balloon of 66 minutes (interquartile range 38-106). Baseline characteristics were similar except for slightly higher incidence of renal dysfunction and prior angina pectoris in SR patients. Time from symptom onset to medical contact was significantly greater in SR patients. Patients with SR had significantly less in-hospital heart failure (4% versus 11%) and cardiogenic shock (0% versus 2%) (P<0.01 for all). No significant differences were found in in-hospital mortality (1% versus 2%), 30-day major cardiac events (4% versus 4%), and mortality at 30 days (1% versus 2%) and 1 year (4% versus 4%).

CONCLUSIONS

Patients with clinically defined SR have a favorable prognosis. Deferring immediate intervention seems to be safe in patients with clinical indices of spontaneous reperfusion.

Immediate response to prasugrel loading in patients with ST-elevation myocardial infarction: Predictors and outcome

INTRODUCTION

Information regarding immediate response to novel P2Y12 inhibitors in ST-elevation myocardial infarction (STEMI) is scarce and has been associated with adequate reperfusion. Recent studies have shown that the onset of anti-platelet effects of novel P2Y12 inhibitors in patients with STEMI might be slower and more variable than in stable coronary syndrome. We aimed to assess the predictors and significance of immediate platelet response to prasugrel loading in STEMI.

METHODS

Platelet aggregation (PA) was prospectively evaluated in STEMI patients upon prasugrel loading and at primary percutaneous coronary intervention (PPCI). Early platelet responsiveness was defined as percent reduction of PA from baseline to PPCI, divided by the time lapse from loading to PPCI. High- and low-platelet responsiveness was defined as above and below the median value respectively.

RESULTS

Fifty consecutive STEMI patients (age 58±8, 90% male) underwent PPCI with a mean door-to-balloon time of 42±15min. Mean PA upon prasugrel loading and at PPCI was 76±9% and 63±19%, respectively. Older age and prior aspirin use were predictors of low platelet responsiveness to prasugrel [β=(-0.33), p=0.02 and β=(-0.28), p=0.04, respectively]. Fast compared with slow responders demonstrated more frequent early ST resolution (93% vs. 72%, p=0.02) and lower peak troponin levels (76±62μg/L vs. 48±28μg/L, p=0.05).

CONCLUSIONS

Immediate platelet responsiveness to prasugrel among STEMI patients is highly variable and inversely associated with older age and prior aspirin use. Fast compared with slow responders have improved reperfusion and infarct size markers.

Association between clinical parameters and ST-segment resolution after primary percutaneous coronary intervention in patients with acute ST-segment elevation myocardial infarction

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate and compare various parameters between complete and incomplete ST-segment resolution (STR) patients' groups and to identify associates of STR in patients with acute ST-segment elevation myocardial infarction (STEMI) after primary percutaneous coronary intervention (PPCI) (primary outcome).

MATERIALS AND METHODS

A total of 203 consecutive patients were divided into two groups according to the degree of STR: <70% (incomplete) and ≥70% (complete resolution) 5-15min after the PPCI. The cardiovascular risk factors, sex, Killip class, Thrombolysis in Myocardial Infarction (TIMI) flow, symptom-onset-to-balloon time and door-to-balloon time, and adverse cardiovascular events (secondary outcome) were assessed and compared between two groups.

RESULTS

There were 147 patients with incomplete STR and 56 patients with complete STR. Patients with complete STR were younger, had lower Killip class, shorter duration of the chest pain and were less likely to have anterior myocardial infarction (AMI). Patients in the incomplete STR group had longer symptom-onset-to-balloon and door-to-balloon intervals. TIMI3 flow after PPCI was more common in the complete STR group. TIMI flow ≤2 after PCI, AMI and symptom onset-to-balloon time were inversely associated with STR (beta coefficients -28.635, -28.611, and -0.917, respectively). AMI (OR=29.9), symptom onset-to-balloon time (OR=1.7) and patient's age (OR=1.1) were associated with an increased likelihood of having incomplete STR.

CONCLUSIONS

Patients with complete STR were younger, had lower Killip class, shorter duration of STEMI, were less likely to have AMI, were more likely to recover TIMI3 flow. Age, TIMI-flow grade 2 or less after PPCI, AMI and symptom-onset-to-balloon time were associated with STR.

Effect of thrombus aspiration on postprocedural outcomes in elderly patients with acute ST-elevation myocardial ınfarction

AIM

The effects of thrombus aspiration (TA) during primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) have been evaluated in several studies. The aim of the present study was to evaluate postprocedural outcomes in elderly STEMI patients who have a tendency for vasoconstruction and decreased coronary flow reserve.

METHODS

A total of 124 patients (aged ≥65 years) with STEMI who underwent primary PCI (71.2% men, 29.8% women, mean age 74 ± 7 years) were enrolled in the study. Patients were divided into two groups according to intervention with and without TA. Acute angiographic, electrocardiographic and echocardiographic results were compared between the two groups.

RESULTS

TA was carried out in 42 patients (33.8%). Baseline clinical characteristics and predischarge echocardiographic features did not differ between TA(+) and TA(-) patients (ejection fraction 37.26 ± 8.91 vs 38.53 ± 11.18, P = 0.558, wall motion index 1.69 ± 0.38 vs 1.76 ± 0.37, P = 0.316, septal E' 0.058 ± 0.022 vs 0.053 ± 0.015, P = 0.267, E/E' 11.82 ± 4.30 vs 13.12 ± 5.09, P = 0.370). Acute angiographic and electrocardiographic results did not differ between the two groups, but were slightly better in the thrombectomy group than those without TA corrected TIMI frame count (31.63 ± 16.33 vs 34.97 ± 15.81, P = 0.197, TIMI-3 88.1% vs 79.3%, P = 0.223, ST segment resolution 81.3% vs 70.3%, P = 0.250).

CONCLUSIONS

Thrombectomy during primary PCI has no effect on postprocedural outcomes in an elderly group with STEMI. Geriatr Gerontol Int 2015; ●●: ●●-●●.

ST peak during percutaneous coronary intervention serves as an early prognostic predictor in patients with ST-segment elevation myocardial

AIMS

To evaluate the clinical importance of the ST peak phenomenon during primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS AND RESULTS

Continuous ST monitoring was performed in 942 STEMI patients from arrival until 90 minutes after revascularisation. ST peak was defined as ≥1 mm increase in the ST-segment during PCI compared with the ST elevation before intervention. ST peak was observed in 26.9% of patients. During median follow-up of 4.1 years, 20.7% of patients experienced a major adverse cardiac event (MACE). ST peak was associated with higher rates of mortality (13.4% versus 9.3%; p=0.044), admission for heart failure (10.6% versus 5.2%; p=0.002) and MACE (26.9% versus 18.2%; p=0.002), but not reinfarction (7.1% versus 5.2%; p=0.14). In two different Cox regression analyses, adjusting for predictors of MACE and ST peak including ST resolution and epicardial flow, ST peak remained significantly associated with MACE: adjusted hazard ratio (HR) 1.40 (95% confidence interval [CI] 1.01-1.95) and 1.41 (95% CI: 1.02-1.96).

CONCLUSIONS

In the largest study hitherto evaluating the ST peak phenomenon during primary PCI, we demonstrated that ST peak is a strong predictor of adverse long-term outcome and provides independent prognostic information beyond that provided by ST resolution and epicardial flow.

Deeply reinverted T wave at 14 days after the onset of first anterior acute myocardial infarction predicts improved left ventricular function at 6 months

BACKGROUND

Changes in electrocardiogram (ECG), especially in the ST segment and T wave, have been recognized as a noninvasive diagnostic tool for coronary flow or myocardial injury.

HYPOTHESIS

A deeply inverted T wave at 14 days after successful percutaneous coronary intervention (PCI) in patients with ST-segment elevation acute myocardial infarction (STEMI) predicts improved left ventricular (LV) function at 6 months.

METHODS

We enrolled 112 consecutive patients (88 men, 63 ± 11 years) with first anterior STEMI who underwent successful PCI. A 12-lead ECG was recorded everyday from admission through 14 days. After PCI, the first T-wave inversion was observed within 2 days, and the second occurred at 14 days. We measured the maximum depth of the reinverted T wave (Neg-T) and divided the patients into 2 groups based on the median value of Neg-T: the deep group (≥0.6 mV, n = 62) and the nondeep group (<0.6 mV, n = 50).

RESULTS

LV ejection fraction (LVEF) at 14 days did not differ between the 2 groups, but it was greater in the deep than in the nondeep group at 6 months (50.0% ± 8.8% vs 42.5% ± 9.8 %, P < 0.0001). The maximum creatinine phosphokinase-myocardial band (CPK-MB) value was significantly lower in the deep than in the nondeep group. Reappearance of the R wave in precordial leads at 6 months was more frequently observed in the deep than in the nondeep group (68% vs 46%, P = 0.02). Multivariate regression analysis showed that the Neg-T and max CPK-MB were independent contributors to LVEF at 6 months.

CONCLUSIONS

A deeply reinverted T wave at 14 days after onset of first anterior STEMI can be a useful predictive marker for improved LV function at 6 months.

B-type natriuretic peptide as a predictor of ischemia/reperfusion injury immediately after myocardial reperfusion in patients with ST-segment elevation acute myocardial infarction

BACKGROUND

In animal models of acute myocardial infarction (AMI), B-type natriuretic peptide (BNP) administered before and during coronary occlusion limits infarct size. However, the relation between plasma BNP levels and ischemia/reperfusion injury remains unclear.

METHODS

302 patients with ST-segment elevation AMI (STEMI) received emergency percutaneous coronary intervention within six hours from the onset. The patients were divided into two groups according to the plasma BNP level before angiography: group L (n=151), BNP ≤ 32.2 pg/ml; group H (n=151), BNP >32.2 pg/ml. The Selvester QRS-scoring system was used to estimate infarct size.

RESULTS

The rate of ischemia/reperfusion injury immediately after reperfusion, defined as reperfusion ventricular arrhythmias (26% vs. 11%, p=0.001) and ST-segment re-elevation (44% vs. 22%, p=0.008), was higher in group L than in group H. Group L had a greater increase in the QRS score during percutaneous coronary intervention (3.55 ± 0.17 vs. 2.09 ± 0.17, p<0.001) and a higher QRS score 1 h after percutaneous coronary intervention (5.77 ± 0.28 vs. 4.51 ± 0.28, p=0.002). On multivariate analysis, plasma BNP levels in the lower 50th percentile were an independent predictor of reperfusion injury (odds ratio, 2.620; p<0.001). The odds ratios of reperfusion injury according to decreasing quartiles of BNP level, as compared with the highest quartile, were 1.536, 3.692 and 4.964, respectively (p trend=0.002).

CONCLUSIONS

Plasma BNP level before percutaneous coronary intervention may be a predictor of ischemia/reperfusion injury and the resultant extent of myocardial damage. Our findings suggest that high plasma BNP levels might have a clinically important protective effect on ischemic myocardium in patients with STEMI who receive percutaneous coronary intervention.

Antiplatelet effect of thienopyridine (clopidogrel or prasugrel) pretreatment in patients undergoing primary percutaneous intervention for ST elevation myocardial infarction

Although previous retrospective studies have suggested the clinical benefits of clopidogrel pretreatment in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI), the antiplatelet effect of thienopyridines during a narrow door-to-balloon time frame has not been evaluated. Seventy-nine consecutive patients with STEMI were treated with either 600 mg of clopidogrel (n = 49) or 60 mg of prasugrel (n = 30) loading on admission. All patients underwent PPCI with a door-to-balloon time of 48 ± 20 minutes. Adenosine diphosphate (ADP)-induced platelet aggregation (PA) was determined by light transmission aggregometry before thienopyridine loading, at PPCI, and after 72 hours. Baseline ADP-induced PA was comparable in clopidogrel- and prasugrel-treated patients (79 ± 10% vs 76 ± 9%, p = 0.2). Although ADP-induced PA was reduced significantly in both clopidogrel- and prasugrel-treated patients (p <0.01 for both), it was significantly lesser in prasugrel-treated patients (63 ± 18% vs 74 ± 12%, p = 0.002). Yet, <50% of the prasugrel-treated patients achieved adequate platelet inhibition (ADP-induced PA <70%) at PPCI. Prasugrel-treated patients, compared with clopidogrel-treated patients, were more likely to have Thrombolysis In Myocardial Infarction myocardial perfusion grade of ≥2 (79% vs 49%, p = 0.01), lower Thrombolysis In Myocardial Infarction frame count (10.2 ± 5.7 vs 13.6 ± 7.2, p = 0.03), and a numerically greater incidence of early ST-segment resolution >50% (26 of 30 [87%] vs 35 of 49 [71%], p = 0.1), suggesting better myocardial reperfusion. In conclusion, overall, prasugrel compared with clopidogrel pretreatment resulted in greater platelet inhibition at PPCI, but even with prasugrel, only <50% of the patients achieved early adequate platelet response.

Relationship between ST-segment resolution and anterior infarct size after primary percutaneous coronary intervention: analysis from the INFUSE-AMI trial

AIMS

ST-segment resolution (STR) after reperfusion therapy has been shown to correlate with prognosis in patients with ST-segment elevation myocardial infarction (STEMI). We investigated whether acute ECG measurements also correlate with ultimate infarct size.

METHODS AND RESULTS

The INFUSE-AMI trial randomized 452 patients with anterior STEMI to intracoronary bolus abciximab vs. no abciximab, and to thrombus aspiration vs. no aspiration. Infarct size as percentage of total LV mass was calculated by cardiac magnetic resonance imaging (MRI) 30 days post intervention. Five ECG methods were analysed for their ability to predict MRI infarct mass: (1) summed STR across all infarct-related ECG leads (ΣSTR); (2) STR in the single lead with maximum baseline ST-segment elevation (maxSTR); (3) summed residual ST-segment elevation across all infarct-related leads at 60 min post intervention (ΣST residual); (4) maximum residual ST-segment elevation in the worst single lead at 60 min post intervention (maxST residual); (5) number of new significant Q-waves (Qwave) at 60 min. All ECG methods strongly correlated with 30-day MRI infarct mass (all p<0.003). Simpler ECG measurements such as maxSTresidual and Qwave were as predictive as more complex measurements. A subset analysis of 158 patients who had microvascular obstruction (MVO) determined by MRI 5 days post intervention also showed strong correlations of MVO with the ECG measures.

CONCLUSIONS

ST-segment and Q-wave changes after primary PCI in anterior STEMI strongly correlated with 30-day infarct size by MRI. In particular, maxST residual and Qwave at 60 min are simple ECG parameters that offer rapid analysis for prognostication.

Relationship Between ST-Segment Recovery and Clinical Outcomes After Primary Percutaneous Coronary Intervention

Background—

In patients with ST-segment elevation myocardial infarction undergoing thrombolytic therapy, the degree of ST-segment resolution (STR) correlates with long-term cardiovascular mortality. The long-term predictive value of STR after primary percutaneous coronary intervention (PCI) is less well understood. We sought to determine the long-term prognostic value of STR after primary PCI in ST-segment–elevation myocardial infarction.

Methods and Results—

In a formal substudy from the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, 2484 patients with ST-segment–elevation myocardial infarction undergoing primary PCI with interpretable baseline and 60-minute post-PCI electrocardiograms had at least 1 mm of baseline ST-segment elevation in ≥2 contiguous leads. Patients were categorized by the degree of STR at 60 minutes: (1) complete (>70%); (2) partial (30%–70%); and (3) absent (<30%). Absent, incomplete, and complete STR were achieved in 514 (20.7%), 712 (28.7%), and 1258 (50.5%) patients, respectively. STR <30% was associated with a greater likelihood of hypertension, diabetes mellitus, longer symptom onset to balloon time, lower left ventricular ejection fraction, and final thrombolysis in myocardial infarction flow <3. At 3 years, patients with STR<30% experienced a higher rate of major adverse cardiovascular events (death, reinfarction, ischemia-driven target vessel revascularization or stroke; 29.9% versus 20.1% versus 19.6%; P <0.0001), ischemia-driven target vessel revascularization (20.4% versus 14.0% versus 11.7%; P <0.001), and mortality (8.4% versus 5.0% versus 5.6%; P =0.03) than those with partial and complete STR, respectively. By multivariable analysis, STR<30% was an independent predictor of 3-year major adverse cardiovascular events (hazard ratio, 1.58; 95% confidence interval, 1.24–2.00; P =0.0002) and 3-year ischemia-driven target vessel revascularization (hazard ratio, 1.87; 95% confidence interval, 1.41–2.48; P <0.0001).

Conclusions—

In this large international study, absent STR 60 minutes after primary PCI was present in ≈1 in 5 patients with ST-segment–elevation myocardial infarction and was a significant independent predictor of major adverse cardiovascular events and target vessel revascularization at 3 years.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00433966

ST peak during primary percutaneous coronary intervention predicts final infarct size, left ventricular function, and clinical outcome

BACKGROUND AND PURPOSE

One third of patients treated with primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction develop a secondary increase in electrocardiographic ST segment (ST peak) during reperfusion. The purpose was to determine the clinical importance of ST peak during primary PCI.

METHODS

A total of 363 patients with ST-elevation myocardial infarction were stratified to no ST peak or ST peak. Final infarct size and ejection fraction (EF) were assessed by cardiovascular magnetic resonance.

RESULTS

Patients with ST peak had a larger infarct size (14% vs 10%; P = .003) and lower EF (53% vs 57%; P = .022). Rates of cardiac mortality (8% vs 3%; P = .047) and cardiac events (cardiac mortality and admission for heart failure; 19% vs 10%; P = .018) were higher among patients with ST peak, but not all-cause mortality (8% vs 5%; P = .46). In a multivariable Cox regression analysis, ST peak remained significantly associated with cardiac events (adjusted hazard ratio, 2.03 [1.08-3.82]).

CONCLUSION

ST peak during primary PCI is related to larger final infarct size, a reduced EF, and adverse cardiac clinical outcome.

The impact of age on effects of pre-hospital initiation of high bolus dose of tirofiban before primary angioplasty for ST-elevation myocardial infarction

PURPOSE

Glycoprotein IIb/IIIa inhibitors are favourable in ST-elevation myocardial infarction (STEMI) patients, and the additional value of early pre-hospital high bolus dose tirofiban has recently been established. The aim of this study was to determine the impact of age on myocardial reperfusion and clinical outcomes of pre-hospital administration of high bolus dose tirofiban.

METHODS

This is a pre-specified sub-analysis of the multicentre, double-blind, placebo-controlled, randomised On-TIME 2 trial and it's open label phase. The primary endpoint was mean residual ST segment deviation 1 h after primary PCI and was evaluated in three age groups.

RESULTS

Of the 466 patients in the highest tertile (≥68 years), median age was 74.4 years (IQR 71.3-78.6 years) and 231 (50%) were randomised to tirofiban. Mean residual ST segment deviation 1 h after PCI was significantly lower in elderly patients pre-treated with tirofiban compared to elderly patients without tirofiban pre-treatment (4.2 ± 5.2 mm vs 6.4 ± 7.5 mm, p = 0.001). Furthermore, elderly patients pre-treated with tirofiban had a non-significantly higher rate of 30-day major or minor bleeding compared to elderly patients without tirofiban pre-treatment (14.2% vs 9.0%, p = 0.088). 30-day net adverse clinical events in elderly patients with- or without tirofiban was not significantly different (11.9% vs 15.2%, p = 0.300).

CONCLUSION

The effect of pre-hospital initiation of high bolus dose tirofiban on myocardial reperfusion, as determined by ST-segment resolution is highest in the elderly patients. However, this was associated with a trend towards more bleeding complications, resulting in a balanced clinical effect after 30-day follow-up. Future studies should evaluate whether the elderly STEMI patient may benefit from highly effective and safer antiplatelet therapy.

Histopathology of aspirated thrombus and its association with ST-segment recovery in patients undergoing primary percutaneous coronary intervention with routine thrombus aspiration

BACKGROUND

In patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) with thrombus aspiration, the histopathology of aspirated thrombus was previously related to long-term mortality. In this study, we sought to investigate the association between histopathology of aspirated thrombus and ST-segment recovery, a marker of microvascular dysfunction, immediately at the end of the PCI procedure.

METHODS

We included 892 STEMI patients who underwent primary PCI with routine thrombus aspiration and for whom combined data on histopathology of aspirated thrombus and ST-segment recovery were available. Patients were categorized according to histopathology of aspirated thrombus: fresh only (<1 day), older (>1 day), or no material aspirated. ST-segment recovery was defined as incomplete if <50%.

RESULTS

Incomplete ST-segment recovery occurred in 134 of 363 patients (37%) with fresh thrombus, in 104 of 238 patients (44%) with older thrombus, and in 142 of 291 patients (49%) with no material. Unadjusted odds ratios for incomplete ST-segment recovery of patients with older thrombus and no material, when compared with patients with fresh thrombus, were 1.33 (95% CI, 0.95-1.85; P = 0.097) and 1.63 (95% CI 1.19-2.23; P = 0.002), respectively. Both associations were unchanged after multivariable adjustment for clinical predictors of ST-segment recovery. ST-segment recovery was a strong predictor of long-term mortality, independent of the histopathology of aspirated thrombus.

CONCLUSIONS

This study shows that ST-segment recovery immediately at the end of the PCI procedure was a significant prognosticator, independent of the histopathology of aspirated thrombus. We found that the histopathology of aspirated thrombus (fresh, older, no material) was associated with ST-segment recovery in STEMI patients undergoing primary PCI with thrombus aspiration.

The first clinical pilot study of intravenous adrenomedullin administration in patients with acute myocardial infarction. J Cardiovasc Pharmacol. 2010;56:413-419. [PMID: 20930593 DOI: 10.1097/FJC.0b013e3181f15b45]

Adrenomedullin (AM) is a 52-amino-acid vasodilator peptide that was originally isolated from human pheochromocytoma. In the previous experimental study with rat ischemia/reperfusion model, AM reduced infarct size and inhibited myocyte apoptosis. AM also suppressed the production of oxygen-free radicals. The present study was designed to evaluate the feasibility of intravenous administration of AM in patients with acute myocardial infarction. We studied 10 patients with first acute myocardial infarction [male to female ratio: 9 to 1, age: 65 ± 9 (mean ± SD) years, peak creatine phosphokinase level: 4215 ± 1933 (SD) U/L], who were hospitalized within 12 hours of symptom onset. Proceeding reperfusion therapy, AM infusion was initiated and continued at concentration of 0.0125-0.025 μg·kg·min for 12 hours. Follow-up coronary angiography and left ventriculography were performed at 3 months. Cardiac magnetic resonance was examined at 1 month and 3 months after AM therapy. During infusion of AM, hemodynamics kept stable except 2 patients. Wall motion index in the infarct area at 3 months was significantly improved compared with that at baseline, and infarct size evaluated by cardiac magnetic resonance was significantly decreased at 3 months. In conclusion, intravenous administration of AM, which possesses a variety of potential cardiovascular protective actions, can be adjunctive to percutaneous coronary intervention.

Does ST resolution achieved via different reperfusion strategies (fibrinolysis vs percutaneous coronary intervention) have different prognostic meaning in ST-elevation myocardial infarction? A systematic review

OBJECTIVE

We perform a systematic review to discern if ST resolution achieved via percutaneous coronary intervention (PCI) has a different meaning to that achieved via fibrinolysis.

BACKGROUND

Resolution of ST-segment elevation in acute myocardial infarction has been widely used as a surrogate for treatment success. A recent randomized study suggested that after primary PCI, the prognostic significance of ST resolution may have been overemphasized.

METHODS

Using the MEDLINE, COCHRANE, EMBASE, and PUBMED databases to search for the relevant papers, we analyze the data with a new ST-resolution score. ST-resolution groups of <30%, 30% to < 70%, and ≥ 70% are given scores of 1, 2, and 3 respectively, whereas ST-resolution groups reported as < 50% are scored as 1.5, and ≥ 50% scored as 2.5.

RESULTS

We identify 18 fibrinolysis cohorts (32,341 patients) and 5 PCI cohorts (1,913 patients). The mean ST-resolution score weighted for the number of patients in each cohort is 1.87 ± 0.15 for PCI and 1.66 ± 0.20 for fibrinolysis (P < .001). The raw combined 30-day mortality is 4.9% with fibrinolysis and 4.3% with PCI (P = .452 by Poisson regression). There is a linear relationship with lower 30-day mortality associated with higher ST-resolution score. The regression line for the PCI cohorts almost overlaps with that from the fibrinolysis cohorts. On multivariate regression, only ST-resolution score is significant in predicting 30-day mortality. When tested, the interaction term (treatment group × ST resolution score) is never a significant predictor (P > .25 in all models).

CONCLUSION

ST resolution after different reperfusion therapies has similar prognostic meaning.

Dynamic Changes in ST Segment Resolution After Myocardial Infarction and the Association with Microvascular Injury on Cardiac Magnetic Resonance Imaging

BACKGROUND

persistent ST elevation after reperfused ST elevation myocardial infarction (STEMI) is believed to be related to poor microvascular perfusion. Cardiac magnetic resonance imaging (CMR) can evaluate microvascular obstruction (MVO) and intramyocardial haemorrhage (IMH) both of which represent severe microvascular damage, have independent prognostic value and are dynamic and evolving over the first 48hours after reperfusion. The aim of this study was to assess whether the development of MVO or IMH has an impact upon ST segment resolution.

METHODS

patients undergoing primary percutaneous coronary intervention (PCI) for STEMI had serial 12 lead electrocardiograms (ECG) from one hour after PCI until discharge. Persistent single lead maximal residual ST elevation (maxSTE) at each time point was calculated. ST segment deterioration (re-elevation) was calculated on each ECG until discharge compared with one hour post PCI ECG. CMR was performed within seven days post infarct utilising T2 weighted imaging to evaluate culprit artery area at risk (AAR) and IMH. Gadolinium delayed enhancement CMR quantified infarct size and MVO.

RESULTS

in the 41 patients studied 58% had MVO and 41% had IMH. ST segment deterioration was more common in those with MVO or IMH (p=0.03 and p=0.008 respectively). MaxSTE was higher at each time point after PCI in those with MVO but only became statistically significant after 24hours. The measurement of maxSTE at 48 or 72hours after revascularisation provided the best correlation with the combination of infarct size, AAR, MVO and intramyocardial haemorrhage.

CONCLUSION

microvascular injury as defined on CMR is associated with dynamic changes and persistence of ST segment elevation in the first 72hours after reperfusion.

Early versus late ST-segment resolution and clinical outcomes after percutaneous coronary intervention for acute myocardial infarction

Background. Absence of complete ST-segment resolution (STR) after percutaneous coronary intervention (PCI) for ST-segment-elevation myocardial infarction (STEMI) is a determinant of mortality. Traditionally, STR is determined on the coronary care unit (CCU) 60 to 90 minutes after the initiation of reperfusion therapy. We studied the prognostic value of STR immediately after PCI. Methods. We analysed 223 consecutive patients with STEMI and successful PCI. Continuous ECG data were collected during PCI and at 30 minutes after arrival on the CCU (mean time 81±17 minutes after reflow of the culprit artery). Patients were divided into three groups: patients with complete STR immediately after PCI ('early'), patients with complete and persistent STR at 30 minutes on the CCU, but not immediately after PCI ('late') and patients without STR. One-year follow-up was obtained for death and rehospitalisation for major adverse cardiac events. Cox proportional hazards regression was used to evaluate the association between STR and outcome. Results. Early STR occurred in 115 (52%) and late STR in 43 (19%) patients. Patients with early or late STR had a lower incidence of one-year cardiac death than those without STR (1.9 vs. 9.2%; p=0.02). In contrast, rehospitalisation occurred more frequently in patients with early or late STR (20.3 vs. 6.2%; p=0.009). As compared with patients without STR, early and late STR had a similar prognostic value (hazard ratios [95% confidence interval] for cardiac death 0.40 [0.08-2.03] and 0.25 [0.03-2.08]).Conclusions. We found no (major) change in prognostic value of STR during the 0 to 90 minutes time window after PCI. (Neth Heart J 2010;18:416-22.).

ST-segment resolution prior to primary percutaneous coronary intervention is a poor indicator of coronary artery patency in patients with acute myocardial infarction

BACKGROUND

The prognostic value of ST-segment resolution (STR) after initiation of reperfusion therapy has been established by various studies conducted in both the thrombolytic and mechanic reperfusion era. However, data regarding the value of STR immediately prior to primary percutaneous coronary intervention (PCI) to predict infarct-related artery (IRA) patency remain limited. We investigated whether STR prior to primary PCI is a reliable, noninvasive indicator of IRA patency in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

The study population consisted of STEMI patients who underwent primary PCI at our institution between 2000 and 2007. STR was analyzed in 12-lead electrocardiograms recorded at first medical contact and immediately prior to primary PCI and defined as complete (> or =70%), partial (70%- 30%), or absent (<30%).

RESULTS

In 1253 patients with a complete data set, STR was inversely related to the probability of impaired preprocedural flow (P(for trend) < 0.001). Although the sensitivity of incomplete (<70%) STR to predict a Thrombolysis in Myocardial Infarction (TIMI) flow of <3 was 96%, the specificity was 23%, and the negative predictive value of incomplete STR to predict normal coronary flow was only 44%.

CONCLUSIONS

This study establishes the correlation between STR prior to primary PCI and preprocedural TIMI flow in STEMI patients treated with primary PCI. However, the negative predictive value of incomplete STR for detection of TIMI-3 flow is only 44% and therefore should not be a criterion to refrain from immediate coronary angiography in STEMI patients.

Influence of ST-segment recovery on infarct size and ejection fraction in patients with ST-segment elevation myocardial infarction receiving primary percutaneous coronary intervention

In patients with ST-segment elevation myocardial infarction treated with fibrinolytics, electrocardiogram-derived measures of ST-segment recovery guide therapy decisions and predict infarct size. The comprehension of these relationships in patients undergoing mechanical reperfusion is limited. We studied 144 patients treated with primary percutaneous coronary intervention. We aimed to define the association between infarct size as determined by cardiac magnetic resonance imaging and different metrics of ST-segment recovery. Electrocardiograms were assessed at baseline and 90 minutes after primary percutaneous coronary intervention. Three methods for calculating and categorizing ST-segment recovery were used: (1) summed ST-segment deviation (STD) resolution analyzed in 3 categories (> or = 70%, > or = 30% to <70%, and <30%); (2) single-lead STD resolution analyzed in the same 3 categories; (3) worst-lead residual STD analyzed in 3 categories (<1 mm, 1 to <2 mm, and > or = 2 mm). Infarct size and ejection fraction were assessed at 4 months by cardiac magnetic resonance imaging. All 3 ST-segment recovery algorithms predicted the final infarct size and cardiac function. Worst-lead residual STD performed the same as, or better than, the more complex methods and identified large subgroups at either end of the risk spectrum (median infarct size from the lowest to highest risk category (percentage of left ventricle: 7.7% [interquartile range 10.8], 13.1% [interquartile range 13.6]; 24.6% [interquartile range 21.1]); with adjusted odds ratios for infarct size greater than the median (reference <1 mm): 1 to <2 mm, odds ratio 2.3 (95% confidence interval 0.8 to 5.9); > or = 2 mm, odds ratio 6.3 (95% confidence interval 1.7 to 23.7; c-index 0.781). In conclusion, an electrocardiogram obtained early after primary percutaneous coronary intervention analyzed by a simple algorithm provided prognostic information on the final infarct size and cardiac function.

Myocardial salvage by CMR correlates with LV remodeling and early ST-segment resolution in acute myocardial infarction

OBJECTIVES

The purpose of this study was to assess the association of myocardial salvage by cardiac magnetic resonance (CMR) with left ventricular (LV) remodeling and early ST-segment resolution in patients with acute myocardial infarction (MI).

BACKGROUND

Experimental studies revealed that MI size is strongly influenced by the extent of the area at risk (AAR), limiting its accuracy as a marker of reperfusion treatment efficacy in acute MI studies. Hence, an index correcting MI size for AAR extent is warranted. T2-weighted CMR and delayed-enhancement CMR, respectively, enable the determination of AAR and MI size, and the myocardial salvage index (MSI) is calculated by correcting MI size for AAR extent. Nevertheless, the clinical value of CMR-derived MSI has not been evaluated yet.

METHODS

In a prospective cohort of 137 consecutive patients with acutely reperfused ST-segment elevation MI, CMR was performed at 1 week and 4 months. T2-weighted CMR was used to quantify AAR, whereas MI size was detected by delayed-enhancement imaging. MSI was defined as AAR extent minus MI size divided by AAR extent. Adverse LV remodeling was defined as an increase in LV end-systolic volume of >or=15%. The degree of ST-segment resolution 1 h after reperfusion was also calculated.

RESULTS

AAR extent was consistently larger than MI size (32+/-15% of LV vs. 18+/-13% of LV, p<0.0001), yielding an MSI of 0.46+/-0.24. MI size was closely related to AAR extent (r=0.81, p<0.0001). After correction for the main baseline characteristics by multivariate analyses, MSI was a major and independent determinant of adverse LV remodeling (odds ratio: 0.64; 95% confidence interval: 0.49 to 0.84, p=0.001) and was independently associated with early ST-segment resolution (B coefficient=0.61, p<0.0001).

CONCLUSIONS

In patients with reperfused ST-segment elevation MI, CMR-derived MSI is independently associated with adverse LV remodeling and early ST-segment resolution, opening new perspectives on its use in studies testing novel reperfusion strategies.