Diabetes mellitus, myocardial reperfusion, and outcome in patients with acute ST-elevation myocardial infarction treated with primary angioplasty (from HORIZONS AMI)

Diabetes mellitus (DM) increases mortality in acute ST-segment elevation myocardial infarction (STEMI) but the responsible mechanism is not fully elucidated. We compared the rate of successful myocardial reperfusion measured by tissue myocardial perfusion grade (TMPG) and outcomes in patients with and without DM undergoing primary percutaneous coronary intervention (PCI) for STEMI. Patients enrolled in the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS AMI) trial were analyzed according to presence of DM with respect to TMPG after PCI and outcomes at 30 days and 3 years. Multivariable logistic regression was performed to identify the independent contribution to mortality of DM and TMPG and the interaction between the 2 was assessed. Complete data were available for 3,265 patients, of whom 533 (16.3%) had DM. Diabetic patients were significantly older and heavier and had more risk factors for coronary disease and more previous MI, revascularization, and heart failure. There were no differences in rates of Thrombolysis In Myocardial Infarction grade 3 flow after PCI in the infarct artery or TMPG 2/3 between patients with and without DM. Compared to nondiabetics, mortality was significantly higher at 30 days and at 3 years in the DM group (1.8% vs 4.5%, p = 0.0002 and 5.4% vs 11.0%, p <0.0001, respectively). DM and TMPG were significantly associated with 3-year mortality, but there was no statistical interaction between DM and TMPG (p = 0.70). In conclusion, DM is associated with a significantly higher risk of death but this association is not mediated by impaired epicardial or myocardial reperfusion.     

Application of the Thrombolysis in Myocardial Infarction risk index in non-ST-segment elevation myocardial infarction: evaluation of patients in the National Registry of Myocardial Infarction.

OBJECTIVES: The purpose of this research was to evaluate the Thrombolysis In Myocardial Infarction risk index (TRI) to characterize the risk of death among patients with non-ST-segment elevation myocardial infarction (NSTEMI). BACKGROUND: The TRI, calculated from baseline age, systolic pressure, and heart rate, was established in patients with ST-segment elevation myocardial infarction (STEMI) and is predictive of mortality. Patients presenting with NSTEMI are increasing compared to STEMI and constitute a group with varied risk. METHODS: The TRI was calculated in 337,192 patients from the National Registry of Myocardial Infarction with NSTEMI. Values and outcomes were compared with 153,486 patients with STEMI classified by reperfusion status. Comparisons of baseline characteristics and clinical outcomes stratified by TRI were made. RESULTS: There was a graded relationship between the TRI and mortality in patients with NSTEMI with a >30-fold difference in mortality rates between lowest and highest deciles (p < 0.0001). The index showed good discrimination (c = 0.73). Overall mortality in the group with NSTEMI was higher (10.9%) than patients with STEMI treated with (6.6%) but lower than for STEMI patients not receiving reperfusion therapy (18.7%). The higher risk in comparison to patients with STEMI treated with reperfusion therapy was explained largely by the higher-risk profile of the population with NSTEMI. CONCLUSIONS: There is a graded relationship between TRI and mortality in patients with NSTEMI. This simple risk index provides important information about mortality in patients across the spectrum of myocardial infarction, STEMI and NSTEMI. Early identification of NSTEMI patients who are at high risk of in-hospital mortality may provide clinicians with important information for initial triage and treatment.     

Quality of care by classification of myocardial infarction: treatment patterns for ST-segment elevation vs non-ST-segment elevation myocardial infarction

BACKGROUND: Practice guidelines for acute ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) recommend similar therapies and interventions, but differences in patterns of care between MI categories have not been well described in contemporary practice. METHODS: In-hospital treatments with similar recommendations from practice guidelines were compared with outcomes in 185 968 eligible patients (without listed contraindications) with STEMI (n = 53 417; 29%) vs NSTEMI (n = 132 551; 71%) from 1247 US hospitals participating in the National Registry of Myocardial Infarction 4 between July 1, 2000, and June 30, 2002. Hierarchical logistic regression modeling was used to determine adjusted differences in treatment patterns in MI categories. RESULTS: Unadjusted in-hospital mortality rates were high for NSTEMI (12.5%) and STEMI (14.3%), and the use of guideline-recommended medications and interventions was suboptimal in both categories of patients with MI. The adjusted likelihood of receiving early (within 24 hours of presentation) aspirin, beta-blockers, and angiotensin-converting enzyme inhibitors was higher in patients with STEMI. Similar patterns of care were noted at hospital discharge: the adjusted likelihood of receiving aspirin, beta-blockers, angiotensin-converting enzyme inhibitors, lipid-lowering agents, smoking cessation counseling, and cardiac rehabilitation referral was higher in patients with STEMI. CONCLUSIONS: Evidence-based medications and lifestyle modification interventions were used less frequently in patients with NSTEMI. Quality improvement interventions designed to narrow the gaps in care between NSTEMI and STEMI and to improve adherence to guidelines for both categories of patients with MI may reduce the high mortality rates associated with acute MI in contemporary practice.     

Percutaneous coronary intervention in patients receiving enoxaparin or unfractionated heparin after fibrinolytic therapy for ST-segment elevation myocardial infarction in the ExTRACT-TIMI 25 trial.

OBJECTIVES: We sought to evaluate whether enoxaparin (ENOX) is superior to unfractionated heparin (UFH) as adjunctive therapy for patients with ST-segment elevation myocardial infarction (STEMI) who receive fibrinolytic therapy and subsequently undergo percutaneous coronary intervention (PCI) by analyzing data from the ExTRACT-TIMI 25 (Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment-Thrombolysis In Myocardial Infarction 25) trial. BACKGROUND: Limited data are available on the use of ENOX compared with UFH as adjunctive therapy in STEMI patients treated with fibrinolytic therapy and subsequent PCI. METHODS: A total of 20,479 STEMI patients who received fibrinolytic therapy were randomized to a strategy of ENOX throughout index hospitalization or UFH for at least 48 h, with blinded study drug to continue if PCI was performed. The primary end point of death or recurrent MI through 30 days was compared for ENOX versus UFH among the patients who underwent subsequent PCI (n = 4,676). RESULTS: After initial fibrinolysis, fewer patients underwent PCI through 30 days in the ENOX versus the UFH group (22.8% vs. 24.2%; p = 0.027). Among patients who underwent PCI by 30 days, the primary end point occurred in 10.7% of ENOX and 13.8% of UFH patients (0.77 relative risk; p < 0.001). There were no differences in major bleeding for ENOX versus UFH (1.4% vs. 1.6%; p = NS). Results were similar when PCI was carried out in patients receiving blinded study drug during PCI (n = 2,178). CONCLUSION: Among patients treated with fibrinolytic therapy for STEMI who underwent subsequent PCI, ENOX administration was associated with a reduced risk of death or recurrent MI without difference in the risk of major bleeding. The strategy of ENOX support for fibrinolytic therapy followed by PCI is superior to UFH and provides a seamless transition from the medical management to the interventional management phase of STEMI without the need for introducing a second anticoagulant in the cardiac catheterization laboratory.     

Comparison of angiographic and other findings and mortality in non-ST-segment elevation versus ST-segment elevation myocardial infarction in patients undergoing early invasive intervention

We sought to compare the angiographic findings and mortality in patients with non-ST-segment elevation (NSTEMI) versus ST-segment elevation myocardial infarction (STEMI) undergoing early invasive intervention. Of 11,872 patients enrolled in the Korean Acute Myocardial Infarction Registry from November 2005 to January 2008, we studied patients with NSTEMI undergoing early invasive intervention (n = 1,486) and those with STEMI undergoing primary percutaneous coronary intervention (n = 4,392). Multivessel coronary disease, baseline Thrombolysis In Myocardial Infarction (TIMI) flow grade 3, and the left circumflex artery as a culprit lesion occurred more frequently in patients with NSTEMI than in those with STEMI. Those with NSTEMI had a significantly lower mortality rate than those with STEMI during a median follow-up of about 12 months (3.8% vs 6.7%, p <0.001). In the patients with NSTEMI, the independent predictors of mortality included postprocedural TIMI flow grade 0 to 2 (hazard ratio [HR] 3.07, 95% confidence interval [CI] 1.01 to 9.29, p = 0.047) and multivessel coronary disease (HR 3.83, 95% CI 1.36 to 10.81, p = 0.010) but not baseline TIMI flow or infarct location. However, baseline TIMI flow grade 0 to 2 (HR 1.56, 95% CI 1.03 to 2.36, p = 0.035), anterior infarction (HR 1.69, 95% CI 1.28 to 2.23, p <0.001), multivessel coronary disease (HR 1.45, 95% CI 1.10 to 1.91, p = 0.008), and postprocedural TIMI flow grade 0 to 2 (HR 2.00, 95% CI 1.42 to 2.82, p <0.001) were all independent predictors of mortality in the patients with STEMI. In conclusion, the angiographic findings in patients from NSTEMI differ from those in patients with STEMI. Postprocedural TIMI flow and multivessel coronary disease were independent predictors of mortality in patients with NSTEMI undergoing early invasive intervention.     

Comparison of outcome in patients with ST-elevation versus non-ST-elevation acute myocardial infarction treated with percutaneous coronary intervention (from the National Heart, Lung, and Blood Institute Dynamic Registry)

Patients with ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) are increasingly being treated with percutaneous coronary intervention (PCI) and we sought to determine risk of adverse outcomes by type of MI. Patients enrolled in the National Heart, Lung, and Blood Institute Dynamic Registry from 1999 to 2004 who presented with an acute MI as an indication for PCI were studied. Baseline data and in-hospital and 1-year outcomes were compared based on ST-segment elevation (STEMI, n = 903; NSTEMI, n = 583) at presentation. Patients with STEMI were younger, had fewer co-morbidities, and had less extensive coronary artery disease than did patients with NSTEMI. Angiographic success and periprocedural complications were similar by MI type. In-hospital coronary artery bypass grafting, stroke, bleeding and recurrent MI were similar but mortality was higher in patients with STEMI (4.0% vs 1.4%, p = 0.004). Cardiogenic shock was associated with the greatest risk of in-hospital death (odds ratio 26.7, 95% confidence interval 11.4 to 62.3, p = 0.0001), but STEMI was also independently predictive of mortality. At 1 year, there was no influence of MI type on outcome. Age, cardiogenic shock, renal disease, peripheral vascular disease, and cancer were predictive of death and MI. Multivessel disease and a larger number of >50% lesions were associated with the need for repeat revascularization. In conclusion, STEMI was associated with a higher likelihood of in-hospital death than was NSTEMI, but long-term outcomes after PCI were independent of MI type. At 1 year, associated co-morbidities were strongly associated with death and MI, whereas only angiographic characteristics predicted the need for repeat revascularization.     

Hyperglycemia is an important predictor of impaired coronary flow before reperfusion therapy in ST-segment elevation myocardial infarction

OBJECTIVES: This study was designed to investigate whether elevated glucose is associated with impaired Thrombolysis In Myocardial Infarction (TIMI) flow before primary percutaneous coronary intervention (PCI). BACKGROUND: Reperfusion before primary PCI in patients with ST-segment elevation myocardial infarction (STEMI) is associated with an improved outcome. Hyperglycemia in patients with STEMI is associated with an adverse prognosis. Hyperglycemia may induce a pro-thrombotic state and therefore be of influence on TIMI flow before PCI. METHODS: A total of 460 consecutive patients with STEMI treated with primary PCI were included in this analysis. Hyperglycemia was defined as a glucose > or =7.8 mmol/l (140 mg/dl). RESULTS: Hyperglycemia was observed in 70% and TIMI flow grade 3 before primary PCI in 17% of the patients. Patients with hyperglycemia less often had TIMI flow grade 3 before primary PCI (12% vs. 28%, p < 0.001). After adjustment for differences in baseline variables, hyperglycemia was a strong predictor of absence of reperfusion before primary PCI (odds ratio 2.6, 95% confidence interval 1.5 to 4.5). CONCLUSIONS: Hyperglycemia in patients with STEMI is an important predictor of impaired epicardial flow before reperfusion therapy has been initiated. Investigation of methods improving coronary flow before primary PCI in these patients is warranted.     

Mean platelet volume on admission predicts impaired reperfusion and long-term mortality in acute myocardial infarction treated with primary percutaneous coronary intervention

OBJECTIVES: We sought to determine the prognostic value of mean platelet volume (MPV) for angiographic reperfusion and six-month mortality in patients with acute ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI). BACKGROUND: Mean platelet volume is predictive of unfavorable outcome among survivors of STEMI when measured after the index event. No data are available for the value of admission MPV in patients with STEMI treated with primary PCI. METHODS: Blood samples for MPV estimation, obtained on admission in 398 consecutive patients presenting with STEMI, were measured before primary PCI. Follow-up up to six months was performed. RESULTS: No-reflow was significantly more frequent in patients with high MPV (> or =10.3 fl) compared with those with low MPV (<10.3 fl) (21.2% vs. 5.5%, p < 0.0001). The MPV was correlated strongly with corrected Thrombolysis In Myocardial Infarction frame count (CTFC) (r = 0.698, p < 0.0001). Kaplan-Meier survival analysis showed six-month mortality rate of 12.1% in patients with high MPV versus 5.1% in low MPV group (log rank = 6.235, p = 0.0125). After adjusting for baseline characteristics, high MPV remained a strong independent predictor of no-reflow (odds ratio [OR] 4.7, 95% confidence interval [CI] 2.3 to 9.9, p < 0.0001), CTFC > or =40 (OR 10.1, 95% CI 5.7 to 18.1, p < 0.0001), and mortality (OR 3.2, 95% CI 1.1 to 9.3, p = 0.0084). Abciximab administration resulted in significant mortality reduction only in patients with high MPV values (OR 0.02, 95% CI 0.01 to 0.48, p = 0.0165). CONCLUSIONS: Mean platelet volume is a strong, independent predictor of impaired angiographic reperfusion and six-month mortality in STEMI treated with primary PCI. Apart from prognostic value, admission MPV may also carry further practical, therapeutic implications.     

Relation between electrocardiographic ST-segment resolution and early and late outcomes after primary percutaneous coronary intervention for acute myocardial infarction

ST-segment resolution (STR) is a surrogate end point in reperfusion trials of acute myocardial infarction, but there are few data regarding the optimum methods of measurement, clinical predictors, and correlation with late cardiac mortality. Consecutive patients (n = 1,005) who had acute myocardial infarction and >/=2 mm ST-segment elevation controlled with primary percutaneous coronary intervention (PCI) constituted our study group. Follow-up was obtained in 97% of patients at a median of 6.2 years. STR measured as maximum ST-segment elevation after PCI provided better discrimination of late cardiac mortality than did STR measured as percent resolution. Complete STR (<1.0 mm ST-segment elevation after PCI) was achieved in only 42% of patients. Anterior infarction, Killip's class 3 to 4, and Thrombolysis In Myocardial Infarction flow grades <2 before PCI and <3 after PCI were strong independent predictors of partial or poor STR. STR (complete [<1.0 mm] vs partial [1.0 to 2.0 mm] vs poor [>2.0 mm]) correlated with in-hospital mortality (4.0% vs 6.7% vs 11.6%, p = 0.005), reinfarction (1.4% vs 3.4% vs 6.1%, p = 0.01), and late cardiac mortality (17% vs 25% vs 44%, p <0.0001). Correlation with late mortality was stronger for nonanterior than for anterior infarction. Poor STR was a strong independent predictor of late mortality (hazard ratio 1.63, 95% confidence interval 1.06 to 2.50, p = 0.028), even after adjusting for Thrombolysis In Myocardial Infarction flow. These data support the use of STR as a simple method to stratify patients by risk after primary PCI for acute myocardial infarction and support the use of STR as a surrogate end point in reperfusion trials of acute myocardial infarction.     

Association of duration of symptoms at presentation with angiographic and clinical outcomes after fibrinolytic therapy in patients with ST-segment elevation myocardial infarction.

OBJECTIVES: We sought to determine if an underlying mechanism of the association between prolonged symptom-to-treatment times and adverse outcomes may be an association of symptom-to-treatment times with impaired Thrombolysis In Myocardial Infarction myocardial perfusion grades (TMPGs). BACKGROUND: Prolonged symptom duration among ST-segment elevation myocardial infarction (STEMI) patients undergoing fibrinolytic therapy is associated with adverse outcomes. METHODS: Angiography was performed 60 min after fibrinolytic administration in 3,845 Thrombolysis In Myocardial Infarction (TIMI) trial patients. RESULTS: The median time from symptom onset to treatment was longer among patients with impaired myocardial perfusion (3.0 h for TMPG 0/1 vs. 2.7 h for TMPG 2/3; p = 0.001). In a multivariate model, impaired tissue perfusion (TMPG 0/1) remained associated with increased time to treatment (odds ratio 1.14 per hour of delay; p = 0.007) even after adjusting for Thrombolysis In Myocardial Infarction flow grade (TFG) 3, left anterior descending infarct location, and baseline clinical characteristics. Impaired myocardial perfusion after rescue/adjunctive percutaneous coronary intervention (PCI) was associated with longer median times to treatment (3.0 h for TMPG 2/3 vs. 2.7 h for TMPG 0/1; p = 0.017), as was abnormal epicardial flow after rescue/adjunctive PCI (3.3 h for TFG 0/1/2 vs. 2.8 h for TFG 3; p = 0.005). Thirty-day mortality was associated with longer time from onset of symptoms to treatment (6.6% mortality for time to treatment >4 h vs. 3.3%; p < 0.001), even among patients undergoing rescue PCI. CONCLUSIONS: A prolonged symptom to treatment time among STEMI patients is associated with impaired myocardial perfusion independent of epicardial flow both immediately after fibrinolytic administration and after rescue/adjunctive PCI. These data provide a pathophysiologic link between prolonged symptoms due to vessel occlusion, impaired myocardial perfusion, and poor clinical outcomes.     

Long-term prognosis of first myocardial infarction according to the electrocardiographic pattern (ST elevation myocardial infarction, non-ST elevation myocardial infarction and non-classified myocardial infarction) and revascularization procedures

The aim of this study was to describe differences in the characteristics and short- and long-term prognoses of patients with first acute myocardial infarction (MI) according to the presence of ST-segment elevation or non-ST-segment elevation. From 2001 and 2003, 2,048 patients with first MI were consecutively admitted to 6 participating Spanish hospitals and categorized as having ST-segment elevation MI (STEMI), non-ST-segment elevation MI (NSTEMI), or unclassified MI (pacemaker or left bundle branch block) according to electrocardiographic results at admission. The proportions of female gender, hypercholesterolemia, hypertension, and diabetes were higher among NSTEMI patients than in the STEMI group. NSTEMI 28-day case fatality was lower (2.99% vs 5.26%, p = 0.02). On multivariate analysis, the odds ratio of 28-day case fatality was 2.23 for STEMI patients compared to NSTEMI patients (95% confidence interval 1.29 to 3.83, p = 0.004). The multivariate adjusted 7-year mortality for 28-day survivors was higher in NSTEMI than in STEMI patients (hazard ratio 1.31, 95% confidence interval 1.02 to 1.68, p = 0.035). However, patients with unclassified MI presented the highest short- and long-term mortality (11.8% and 35.4%, respectively). The excess of short-term mortality in unclassified and STEMI patients was mainly observed in those patients not treated with revascularization procedures. In conclusion, patients with first NSTEMI were older and showed a higher proportion of previous coronary risk factors than STEMI patients. NSTEMI patients had lower 28-day case fatality but a worse 7-year mortality rate than STEMI patients. Unclassified MI presented the worst short- and long-term prognosis. These results support the invasive management of patients with acute coronary syndromes to reduce short-term case fatality.     

Safety and efficacy of the FilterWire EZ in acute ST-segment elevation myocardial infarction

Primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) achieves a high epicardial reperfusion rate; however, it is often suboptimal in achieving myocardial reperfusion due to distal embolization of atherothrombotic particles. The present study assessed whether the capture of embolic particles during PCI would improve myocardial reperfusion outcome. In a multicenter, prospective, randomized, controlled study, 100 patients with STEMI and coronary angiographic evidence of thrombotic occlusion were randomly assigned to PCI using the FilterWire EZ (n=51) or a control group (n=49) using regular guidewires. The FilterWire EZ was successfully delivered across the lesion in 84% of patients in the FilterWire EZ group. Primary efficacy end points, including markers of epicardial (Thrombolysis In Myocardial Infarction grade flow) and myocardial reperfusion (myocardial blush score and percent early resolution of ST-segment elevation), did not differ between the 2 study groups. Further, 60- and 90-minute percent ST-segment resolutions were identical in the 2 groups. In a subgroup analysis, a blush score of 3 was achieved in 94% of patients in whom the filter's landing zone was in a vessel diameter>2.5 mm compared with only 55% in those with smaller vessel diameter (p=0.04). This corresponds to a better debris capture in filters located in large versus small vessels (p=0.08). In conclusion, in patients with STEMI, use of the FilterWire EZ as an adjunct to primary PCI did not improve angiographic or electrocardiographic measurements of reperfusion compared with conventional PCI only.     

Relation between leucocyte count, myonecrosis, myocardial perfusion, and outcomes following primary angioplasty

We examined whether leukocytosis is a negative prognostic factor in patients who underwent primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI), and, if so, determined whether it is associated with impaired myocardial perfusion. Previous studies have identified leukocytosis as a predictor of mortality in AMI. Whether this association holds in patients how have undergone primary PCI using contemporary pharmacotherapy and correlates with impaired myocardial perfusion is unknown. Clinical outcomes and reperfusion success, using Thrombolysis In Myocardial Infarction (TIMI) flow and myocardial blush grades, were examined according to tertiles of baseline leukocyte count in 1,268 patients who underwent primary PCI for AMI in the CADILLAC trial. Patients with higher leukocyte count were younger and more likely to be current smokers. Preprocedure TIMI grade 0 flow was more frequent in patients with higher leukocyte counts, but postprocedural TIMI grade 3 flow rates were equally high (>94%) in all 3 groups. Myocardial blush grade 2/3 was achieved at similar rates after PCI in patients with low, intermediate, and high baseline leukocyte counts (52.0% vs 51.5% vs 50.1%, p = 0.8). Higher baseline leukocyte counts were associated with greater myonecrosis (p <0.0001) and increased mortality at 1 year (2.7% vs 4.6% vs 5.4%, respectively, p = 0.047). By multivariate analysis, baseline leukocyte count (in increments of 1,000, hazard ratio 1.07, 95% confidence interval 1.02 to 1.10, p = 0.005) and peak creatine phosphokinase (hazard ratio 1.22, 95% confidence interval 1.14 to 1.29, p <0.001) were independent predictors of 1-year mortality. In conclusion, baseline leukocytosis is an independent correlate of larger infarct and increased mortality after primary PCI in AMI, an effect not explained by decreased myocardial perfusion.     

Association of a negative residual stenosis following rescue/adjunctive percutaneous coronary intervention with impaired myocardial perfusion and adverse outcomes among ST-segment elevation myocardial infarction patients

OBJECTIVES: We hypothesized that <0% residual stenosis (RS) after rescue/adjunctive percutaneous coronary intervention (PCI) following fibrinolytic administration in ST-segment elevation myocardial infarction (STEMI) would be associated with improved outcomes. BACKGROUND: Prior studies have associated larger lumen diameters after PCI with reduced rates of restenosis and target vessel revascularization. METHODS: Data were drawn from 748 patients with open epicardial arteries and with optimal luminal results (RS <20%) following rescue/adjunctive PCI after fibrinolytic administration in six STEMI trials. Patients were divided into two groups: 1) <0% RS and 2) 0% to 20% RS. RESULTS: A RS <0% was associated with greater gains in lumen diameter and smaller reference diameters after PCI (p < 0.001 for each), with a trend toward less frequent Thrombolysis In Myocardial Infarction flow grade (TFG) 3. A RS <0% was associated with a greater incidence of abnormal post-PCI Thrombolysis In Myocardial Infarction myocardial perfusion grades (TMPGs) (odds ratio 2.6 [1.2 to 5.9] for TMPG 0/1/2, p = 0.02), even when the analysis was restricted to patients with post-PCI TFG 3. CONCLUSIONS: A RS <0% following rescue/adjunctive PCI after fibrinolytic therapy for STEMI was independently associated with a reduction in the frequency of normal myocardial perfusion. Potential mechanisms of this finding include greater downstream embolization, increased stimulation of arterial stretch receptors with resultant coronary vasoconstriction, and increased vessel-wall injury after PCI. These findings suggest that additional prospective studies are needed to assess optimal RS that minimizes long-term restenosis without adverse effects.     

Effects of glucose-insulin-potassium infusion on myocardial perfusion and left ventricular remodeling in patients treated with primary angioplasty for ST-elevation acute myocardial infarction

The role of glucose-insulin-potassium (GIK) infusion in the management of acute coronary syndrome is controversial. Limited data are available on the effects of adjunctive high-dose GIK (30% glucose, 50 IU of insulin, 80 mEq of potassium chloride infused at 1.5 ml/kg/hour over 24 hours) on myocardial perfusion and left ventricular (LV) remodeling in patients treated with primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction. In this prospective study, 73 patients were randomized to receive GIK infusion (n = 40) or saline (placebo, n = 33) in addition to standard therapy. The primary end points were myocardial perfusion after PCI and LV remodeling at 6 months. Thrombolysis In Myocardial Infarction frame count and myocardial blush grade were evaluated before and after reperfusion treatment. LV end-diastolic and end-systolic volumes, ejection fraction, and wall motion score index were assessed in each patient after PCI and after 6 months. Although no differences in final Thrombolysis In Myocardial Infarction flow were observed between the 2 groups, myocardial blush grade 3 was more frequently achieved in the GIK group (p <0.05). At 6 months, ventricular remodeling was more often observed in the control group (24% vs 3%, p <0.05). In conclusion, GIK infusion in adjunct to primary PCI in patients with ST-segment elevation myocardial infarction was safe, improved myocardial perfusion after revascularization, and was associated with less LV remodeling at follow-up.     

Comparison of effectiveness of primary angioplasty for proximal versus distal right coronary artery culprit lesion during acute myocardial infarction

From the cohort of 4,023 patients enrolled in the Primary Angioplasty for Myocardial Infarction (PAMI) trials, we pooled clinical, angiographic, and outcomes data on 1,521 patients with culprit lesions in the right coronary artery (RCA). We compared angiographic results, procedural complications, and in-hospital and 1-year clinical outcomes between patients with proximal RCA (n = 572) versus nonproximal RCA culprit lesions (n = 949). Patients with proximal RCA culprit lesions were older, had lower systolic blood pressure, greater diameter stenosis, and were less likely to have Thrombolysis In Myocardial Infarction (TIMI) 2 or 3 flow (19% vs 31%; p <0.0001) before percutaneous coronary intervention (PCI). After PCI, the incidence of TIMI 3 flow (94% vs 93%) was similar between groups. Patients with proximal RCA lesions were more likely to have bradyarrhythmias (30% vs 23%, p = 0.016) and require an intra-aortic balloon pump (IABP; 4.6% vs 2%, p = 0.034) during PCI. In-hospital complications, including mortality (2.3% vs 2.2%) and reinfarction (1.4% vs 1.1%), and the 1-year incidence of death, reinfarction, ischemia driven target vessel revascularization, and major adverse cardiovascular events were similar between groups. After adjustment for baseline differences, proximal RCA location of the culprit lesion was independently associated with greater IABP use (odds ratio 2.41, 95% confidence interval 1.04 to 5.58) but not with bradyarrhythmias during PCI. Thus, in patients with acute myocardial infarction referred for primary angioplasty, proximal RCA location of the culprit lesion is associated with excellent clinical outcomes that are similar to nonproximal RCA lesions.     

Impact of Scheduled Angiographic Follow‐Up in Patients Treated With Primary Percutaneous Coronary Intervention for ST‐Segment Elevation Myocardial Infarction

Routine scheduled angiographic follow‐up (SAF) after percutaneous coronary intervention (PCI) has been associated with a higher rate of target vessel revascularization (TVR). Its benefits are not known. SAF at 13 months after ST‐segment elevation myocardial infarction (STEMI) was planned in the first 1,800 successfully stented patients enrolled in the Harmonizing Outcomes with RevascularIZatiON and Stents in Acute Myocardial Infarction (HORIZONS‐AMI) trial. We compared the outcomes of patients with and without SAF at 1 year (before SAF) and at 3 years (after SAF). There were 1,197 patients (66.5% of expected) with and 2,207 patients without SAF. Prior to SAF, the 1‐year composite rate of death or myocardial infarction (MI) was not significantly different between the 2 groups (2.7% vs. 3.9%, respectively, P = 0.06), although the rate of death was lower (0.1% vs. 2.2%, P < 0.0001), nor were there differences in the 1‐year rates of TVR, stent thrombosis or major adverse cardiac and cerebral events). At 3 years, death or MI rates were again similar between the groups (8.3% vs. 9.5%, P = 0.22), but TVR was more common in the SAF group (17.0% vs. 8.6%, P < 0.0001), due to an increase in TVR at time of SAF. In the SAF group, patients in whom TVR was performed before or after the 13‐month SAF window had markedly higher 3‐year rates of MI and stent thrombosis than patients in whom TVR was performed during SAF or not at all. In conclusion, SAF after primary PCI in STEMI is associated with doubling of the rate of revascularization without an improvement in death or MI, and therefore cannot be recommended.

     

Effect of impaired myocardial reperfusion on left ventricular remodeling in patients with anterior wall acute myocardial infarction treated with primary coronary intervention

We assessed the effect of impaired myocardial blush after primary coronary intervention (PCI) on left ventricular remodeling in patients with ST-segment elevation myocardial infarction (STEMI). The study population consisted of 145 patients with first anterior STEMI that was treated successfully (Thrombolysis In Myocardial Infarction grade 3 flow) with PCI. Left ventricular remodeling was defined as an increase of > or =20% in end-diastolic volume based on repeated echocardiographic measurements in patients. The study population was divided into 2 groups according to the presence (myocardial blush grade [MBG] 2 to 3, n = 86) or absence (MBG 0 to 1, n = 59) of myocardial reperfusion. Left ventricular remodeling appeared in 21% of the entire study group. Poor myocardial blush after PCI was associated with an increased rate of remodeling compared with good myocardial reperfusion (32% vs 14%, hazard ratio 2.308, 95% confidence interval [CI] 1.21 to 4.39, p=0.014). Symptoms of heart failure were observed significantly more often in patients with MBG 0 to 1 (35.6% vs 18.6%, p = 0.032) than in patients with MBG 2 to 3. In multivariate analysis, only age (odds ratio 0.96, 95% CI 0.92 to 0.99, p = 0.02) and MBG 0 to 1 (odds ratio 3.15, 95% CI 1.35 to 7.31, p = 0.008) were associated with left ventricular dilation. In conclusion, impaired microvascular reperfusion is associated with left ventricular remodeling and development of congestive heart failure in patients with anterior STEMI that is treated with primary coronary angioplasty.     

X-sizer for thrombectomy in acute myocardial infarction improves ST-segment resolution: results of the X-sizer in AMI for negligible embolization and optimal ST resolution (X AMINE ST) trial

OBJECTIVES: We sought to compare, in a prospective randomized multicenter study, the effect of adjunctive thrombectomy using X-Sizer (eV3, White Bear Lake, Minnesota) before percutaneous coronary intervention (PCI) versus conventional PCI in patients with acute myocardial infarction (AMI) for <12 h and Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 to 1. The primary end point was the magnitude of ST-segment resolution after PCI. BACKGROUND: Despite a high rate of TIMI flow grade 3 achieved by PCI in patients with AMI, myocardial reperfusion remains relatively low. Distal embolization of thrombotic materials may play a major role in this setting. METHODS: We conducted a prospective, randomized, multicenter study in patients with AMI <12 h and initial TIMI flow grade 0 to 1 who were treated with primary PCI. The magnitude of ST-segment resolution 1 h after PCI was the primary end point. RESULTS: A total of 201 patients were included. Treatment groups were comparable by age (61 +/- 13 years), diabetes (22%), previous MI (8%), anterior MI (52%), onset-to-angiogram (258 +/- 173 min), and glycoprotein IIb/IIIa inhibitor use (59%). The magnitude of ST-segment resolution was greater in the X-Sizer group compared with the conventional group (7.5 vs. 4.9 mm, respectively; p = 0.033) as ST-segment resolution >50% (68% vs. 53%; p = 0.037). The occurrence of distal embolization was reduced (2% vs. 10%; p = 0.033) and TIMI flow grade 3 was obtained in 96% vs. 89%, respectively (p = 0.105). Myocardial blush grade 3 was similar (30% vs. 31%; p = NS). Six-month clinical outcome was comparable (death, 6% vs. 4% and major adverse cardiac and cerebral events, 13% vs. 13%, respectively). By multivariate analysis, independent predictors of ST-segment resolution >50% were: younger age, non-anterior MI, use of the X-Sizer, and a short time interval from symptom onset. CONCLUSIONS: Reducing thrombus burden with X-Sizer before stenting leads to better myocardial reperfusion, as illustrated by a reduced risk of distal embolization and better ST-segment resolution.     

Performance of the thrombolysis in myocardial infarction risk index in the National Registry of Myocardial Infarction-3 and -4: a simple index that predicts mortality in ST-segment elevation myocardial infarction

OBJECTIVES: We sought to evaluate a simple risk index based on age and vital signs in a community sample of patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND: A simple risk index based on age and vital signs (heart rate x [age/10](2)/systolic blood pressure) developed from patients with STEMI accurately predicts mortality in clinical trials of fibrinolysis. The application of such a tool in an unselected population is necessary to evaluate its utility in clinical practice. METHODS: To evaluate the Thrombolysis In Myocardial Infarction (TIMI) risk index for routine practice, we tested it in the National Registry of Myocardial Infarction (NRMI)-3 and -4. The risk index was evaluated as a continuous variable in patients with STEMI from NRMI and in subgroups based on age and reperfusion status. RESULTS: A total of 153,486 patients with STEMI were eligible. As anticipated, STEMI patients in NRMI had a higher risk index profile, as compared with those in the clinical trial (median 26.9 vs. 20, p < 0.0001). Classification of NRMI patients with STEMI into risk groups revealed a significant graded relationship with mortality (0.9% to53.2%, p(trend) < 0.0001, c statistic 0.79). The discriminatory capacity of the risk index was particularly strong in the 81,679 patients receiving reperfusion therapy (0.6% to60%, p(trend) < 0.0001, c statistic 0.81). For the 71,807 patients not receiving reperfusion therapy, a strong graded relationship remained (1.9% to 52.2%, p(trend) < 0.0001, c statistic 0.71). Among the elderly, although the distribution of scores was shifted toward higher risk, the performance remained (0% to 53.1%, p(trend)< 0.0001, c statistic 0.71). CONCLUSIONS: A simple risk index from baseline clinical variables routinely obtained at the first patient encounter predicted mortality in a large unselected heterogeneous group of patients with STEMI.