A randomized comparison of direct stenting with conventional stent implantation in selected patients with acute myocardial infarction.

OBJECTIVES: We sought to determine whether direct stenting might prevent the adverse events associated with stent implantation during primary angioplasty and to compare it with conventional stent implantation in patients with acute myocardial infarction (AMI). BACKGROUND: No trial has demonstrated that stents favorably influence mortality rate. Recent studies have even suggested a negative impact of stents on coronary blood flow and clinical outcome. METHODS: Of 409 patients treated by primary angioplasty with stent implantation in our center, 206 (50%) were enrolled in this randomized, single-center trial and allocated to direct stent implantation (n = 102) or stent implantation after balloon pre-dilation (n = 104). The study end points included angiographic results (final corrected Thrombolysis In Myocardial Infarction [TIMI] frame count and a composite end point of slow and no-reflow or distal embolization), an electrocardiogram marker of myocardial reperfusion assessment (ST-segment resolution) and in-hospital clinical outcome (death and recurrent infarction). RESULTS: Direct stent implantation failed in eight patients but succeeded after pre-dilation in all. A non-significant increase in TIMI flow grade 3 was achieved after direct stenting (95.1% vs. 93.3%, p = 0.74) without significant difference in the corrected TIMI frame count (31.5 +/- 17 and 35.2 +/- 20 frames after direct and conventional stent, respectively, p = 0.42). The composite angiographic end point was significantly reduced by direct stent implantation (11.7% vs. 26.9%, p = 0.01). ST-segment resolution was also significantly improved after direct stent (no ST-segment resolution in 20.2% vs. 38.1% after direct and conventional stent, respectively, p = 0.01). Death and/or recurrent infarction occurred in six patients after conventional stent implantation and in two patients after direct stenting (p = 0.28). CONCLUSIONS: In selected patients with AMI, direct stenting can be applied safely and effectively. This strategy may result in a significant reduction of microvascular injury, as suggested by improved ST-segment resolution after reperfusion with major potential clinical consequences.     

Differences in TIMI frame count following successful reperfusion with stenting or percutaneous transluminal coronary angioplasty for acute myocardial infarction

The Thrombolysis In Myocardial Infarction (TIMI) flow grade achieved in the infarct-related artery (IRA) during reperfusion therapy for acute myocardial infarction (AMI) is directly related to myocardial salvage. Recently, several series have demonstrated the safety of stenting in AMI and documented a larger postprocedure luminal diameter than that found at angioplasty, although no study has compared the effect of PTCA and stenting in AMI on flow characteristics of the IRA. The residual stenosis and the number of frames required to opacify standardized angiographic landmarks normalized for vessel length (corrected TIMI frame count) or compared with flow in a corresponding normal coronary artery (TIMI frame count index) were determined for the IRA of 39 patients who underwent angioplasty or stenting for AMI. Baseline characteristics were similar for the 20 patients who underwent stenting and the 19 patients who underwent percutaneous transluminal coronary angioplasty. After intervention, the luminal diameter was greater (3.24 vs 2.09 mm, p <0.0001) and the residual stenosis was less (-9.4% vs. 26.7%, p <0.0001) after stenting than after percutaneous transluminal coronary angioplasty. These changes in vessel geometry were associated with a lower corrected TIMI frame count (16.1 vs 30.7, p <0.002) and a lower TIMI frame count index (0.68 vs 1.3, p <0.002). Thus, stenting in AMI is associated with a greater postprocedure luminal diameter and improvement in coronary blood flow as measured by the TIMI frame count method.     

Comparison of direct stenting versus conventional stent implantation on blood flow in patients with ST-segment elevation myocardial infarction

As compared with balloon angioplasty, stent implantation in treatment of acute myocardial infarction (AMI) reduces abrupt vessel closure, restenosis, and reocclusion rate. However, a few studies have demonstrated the safety and feasibility of direct stenting compared to conventional stent implantation technique. This study was designed to compare possible advantages of direct stenting with conventional stent implantation on immediate coronary blood flow and short-term clinical benefits in patients with AMI. Fifty patients with AMI who underwent mechanical revascularization were eligible for the study. The patients were randomly assigned to undergo either direct stenting (n = 25) or conventional stent implantation (n = 25). Before and after the procedure thrombolysis in myocardial infarction (TIMI) flow and postprocedural corrected TIMI frame count (cTFC) of the infarct-related artery were measured. There was no difference in TIMI flow distribution at baseline between the 2 groups. TIMI 3 flow rate significantly increased after procedure in both groups compared to baseline (p < 0.05). Postprocedural cTFC was found significantly lower in the direct stent arm compared to conventional stenting (p < 0.001). Both during and after the procedure the complication rate and procedural time were lower in the direct stenting arm. Direct stenting provides better immediate coronary blood flow and is a safe and feasible method compared with conventional stenting in patients with AMI. Improvement in coronary blood flow measured by the corrected TIMI frame count method may suggests a significant reduction of microvascular injury.     

Persistent ST-segment elevation after primary stenting for acute myocardial infarction: its relation to left ventricular recovery

BACKGROUND: Early restoration of coronary artery patency in acute myocardial infarction (AMI) has been linked to improvement in survival. However, early recanalization of an occluded epicardial coronary artery by either thrombolytic agents or percutaneous transluminal coronary angioplasty (PTCA) does not necessarily lead to left ventricular (LV) function recovery. HYPOTHESIS: The aim of this study was to evaluate the relation between persistent ST elevation shortly after primary stenting for acute myocardial infarction (AMI) and LV recovery. METHODS: Thirty-one patients with primary stenting for AMI were prospectively enrolled. To evaluate the extent of microvascular injury, serial ST-segment analysis on a 12-lead electrocardiogram recording just before and at the end of the coronary intervention was performed. Persistent ST-segment elevation (Persistent Group, n = 11) was defined as > or = 50% of peak ST elevation and resolution (Resolution Group, n = 20) was defined as < 50% of peak ST elevation. Echocardiography was performed on Day 1 and 3 months after primary stenting. RESULTS: At 3 months, infarct zone wall-motion score index (WMSI, 2.1 +/- 0.6 vs. 2.7 +/- 0.3, p < 0.05) was smaller in the Resolution Group than in the Persistent Group, whereas wall motion recovery index (RI, 0.4 +/- 0.3 vs. 0.1 +/- 0.2, p < 0.05) and ejection fraction (58 +/- 5 vs. 43 +/- 10%, p < 0.05) were larger in the Resolution Group than in the Persistent Group. The extent of persistent ST elevation (% ST) shortly after successful recanalization of the infarct-related artery was significantly related to RI at 3 months (r = -0.4, p < 0.05). However, time to reperfusion was not related to RI at 3 months. There was also significant correlation between corrected TIMI frame count and %ST (r = 0.4, p < 0.05). CONCLUSIONS: Persistent ST-segment elevation shortly after successful recanalization (> or = 50% of the peak value), as a marker of impaired microvascular reperfusion, predicts poor LV recovery 3 months after primary stenting for AMI.     

Comparison in patients having primary coronary angioplasty of abciximab versus tirofiban on recovery of left ventricular function

In patients treated with primary coronary angioplasty, the use of abciximab improves microvascular perfusion and enhances the recovery of contractile function. This study compared the effects of the new dose regimen of tirofiban (25-microg/kg bolus followed by an 18-hour infusion at 0.15 microg/kg/min) on left ventricular function with those of abciximab in patients who underwent direct angioplasty. One hundred patients who underwent primary coronary angioplasty were randomized to receive a standard dose of abciximab or a large-dose bolus of tirofiban. The primary end point of the study was change in the infarct-zone wall motion score index between the initial and 30-day follow-up echocardiographic studies. The secondary end points were procedural evaluations before and after Thrombolysis In Myocardial Infarction (TIMI) grade flow, TIMI grade myocardial perfusion, and corrected TIMI frame count. Baseline global and regional ventricular functions were similar in the 2 treatment groups. After the procedure, a TIMI grade 3 flow was obtained in 86% of patients treated with abciximab and 88% of those receiving tirofiban (p = 1.0), whereas TIMI grade 3 myocardial perfusion was present in 70% and 76%, respectively (p = 0.65); corrected TIMI frame count was 22.5 +/- 1.9 and 22.1 +/- 2.5 (p = 0.37). After 30 days, we obtained 87 paired echocardiographic studies. The infarct-zone wall motion score index decreased from 2.20 +/- 0.3 to 1.99 +/- 0.2 in the abciximab group and from 2.18 +/- 0.3 to 1.95 +/- 0.3 in the tirofiban group (p = 0.67). Thus, in patients who had primary coronary angioplasty, abciximab, and the large-dose bolus of tirofiban showed similar effects on the initial angiographic results and 30-day recovery of left ventricular function.     

Effects of a distal protection device during primary stenting in patients with acute anterior myocardial infarction.

BACKGROUND: The angiographic no-reflow phenomenon is an adverse prognostic factor in patients with acute myocardial infarction (AMI). The aim of the present study was to evaluate the effects of an occlusive balloon type distal protection device (PercuSurge GuardWire: GW) during primary stenting in patients with anterior AMI. METHODS AND RESULTS: The GW group included 42 patients treated by primary stenting with GW protection and the control group included 30 patients treated by primary stenting after thrombectomy without distal protection. Left ventricular (LV) function was measured and compared by left ventriculography obtained soon after percutaneous coronary intervention (PCI) and 3 weeks after onset. The corrected TIMI frame count values were lower in the GW group than in the control group (27.5+/-2.3 vs 35.1 +/-2.5, p=0.030). The number of patients with myocardial blush grade 3 after PCI was higher in the GW group than in the control group (45.7 vs 20.0%, p=0.029). Peak concentration of creatine kinase myocardial fraction was lower in the GW group than in the control group (326.6+/-41.5 vs 454.9+/-46.2 mg/dl, p=0.043). GW patients showed greater improvement at 3 weeks after PCI in terms of LV ejection fraction (+4.6+/-1.2 vs -1.1+/-1.5, p=0.004), LV end-systolic volume index (+0.5+/-2.4 vs +9.0+/-2.7, p=0.023), and regional wall motion abnormalities (-2.03+/-0.14 vs -2.51+/-0.14, p=0.018). CONCLUSION: Primary stenting with GW protection can restore epicardial coronary flow and myocardial perfusion, and also preserve LV function in anterior AMI.     

Determinants and prognostic significance of spontaneous coronary recanalization in acute myocardial infarction

Spontaneous recanalization (SR) occurs after the onset of acute myocardial infarction (AMI), but its clinical significance in the reperfusion era remains uncertain. We evaluated the determinants and prognostic significance of SR in 196 consecutive patients with AMI who underwent primary angioplasty at our institution. The study population was divided into 2 groups according to the presence (group I, n = 44) or absence (group II, n = 152) of SR (Thrombolysis In Myocardial Infarction [TIMI] anterograde > or = 2 flow on the preintervention angiogram). The primary end point was the occurrence, within 6-weeks after AMI, of death, nonfatal reinfarction, and congestive heart failure. Baseline characteristics were similar between the 2 groups. Peak levels of creatine kinase were lower in group I than in group II (2,500 +/- 1,800 vs 4,000 +/- 2,900 U/L, respectively, p < 0.05). The rate of TIMI flow grade 3 after intervention was higher in group I than in group II (93.2% vs 79.6%, respectively, p < 0.05), and patients in group I had a faster corrected TIMI frame count than those in group II (22.7 +/- 12.4 vs 30.3 +/- 22.8, respectively, p < 0.05). Preinfarction angina (odds ratio [OR] 2.18, 95% confidence interval [CI] 1.10 to 4.33, p < 0.05), heavy thrombi (OR 0.10, 95% CI 0.01 to 0.74, p < 0.05), and good angiographic collaterals (OR 0.12, 95% CI 0.02 to 0.89, p < 0.05) were independent predictors of SR. Death, reinfarction, and severe arrhythmia were not different between the 2 groups. However, heart failure occurred more frequently in group II than in group I (15.1% vs 2.3%, respectively, p < 0.05). The primary end point was also significantly lower in group I than in group II (4.5% vs 18.4%, respectively, p < 0.05). In conclusion, SR in AMI is associated with faster coronary flow, smaller infarct size, and a better clinical outcome after primary angioplasty.     

Association of peripheral neutrophilia with adverse angiographic outcomes in ST-elevation myocardial infarction

We hypothesized that absolute and relative neutrophilia would be associated with adverse angiographic outcomes in the 394 patient Limitation of Myocardial Infarction Following Thrombolysis in Acute Myocardial Infarction (LIMIT) Acute Myocardial Infarction (AMI) trial of fibrinolysis in ST-elevation myocardial infarction. The mean neutrophil count was 7.9 x 10(9)/L, with a mean neutrophil percentage of 72%. Patients with time from symptom onset to fibrinolytic treatment more than the median (2.7 hours) had a higher neutrophil count and percentage of neutrophils than patients with shorter time to treatment. Patients with a closed infarct-related artery at 90 minutes (Thrombolysis In Myocardial Infarction [TIMI] grade 0/1 flow) had higher neutrophil counts (8.8 +/- 3.8 vs 7.6 +/- 3.0, p = 0.02) but no difference in the percentage of neutrophils than patients with an open artery. Higher neutrophil counts were also mildly correlated with longer corrected TIMI frame counts (CTFC) in the infarct-related artery (r = 0.14, p = 0.02). Patients with impaired myocardial perfusion by TIMI myocardial perfusion grade (TMPG) had a greater percentage of neutrophils (73.2 +/- 10.7% for TMPG 0/1 vs 69.9 +/- 12.6% for TMPG 2/3, p = 0.047) but no detectable difference in neutrophil counts (8.2 +/- 3.3 vs 7.7 +/- 2.9, p = 0.24). There were no significant associations between other indexes in the cell differential and angiographic or clinical outcomes. Higher neutrophil counts remained independently associated with both closed arteries and CTFC in multivariable models controlling for age, left anterior descending artery infarct location, time to treatment, and pulse and blood pressure on admission. A greater percentage of neutrophils remained independently associated with impaired microvascular perfusion in a similar multivariable model. In patients with ST-elevation myocardial infarction, absolute and relative neutrophilia were associated with impaired epicardial and microvascular perfusion.     

Randomized early versus late abciximab in acute myocardial infarction treated with primary coronary intervention (RELAx-AMI Trial).

OBJECTIVES: This prospective randomized trial evaluates the impact of early abciximab administration on angiographic and left ventricular function parameters. BACKGROUND: Glycoprotein IIb/IIIa inhibitors improve myocardial reperfusion in patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI), but optimal timing of administration remains unclear. METHODS: Two-hundred ten consecutive patients with first AMI undergoing primary PCI were randomized to abciximab administration either in the emergency room (early group: 105 patients) or in the catheterization laboratory, after coronary angiography (late group: 105 patients). Primary end points were initial Thrombolysis In Myocardial Infarction (TIMI) flow grade, corrected TIMI frame count (cTFC), and myocardial blush grade (MBG), as well as left ventricular function recovery as assessed by serial echocardiographic evaluations. RESULTS: Angiographic pre-PCI analysis showed a significantly better initial TIMI flow grade 3 (24% vs. 10%; p = 0.01), cTFC (78 +/- 30 frames vs. 92 +/- 21 frames; p = 0.001), and MBG 2 or 3 (15% vs. 6%; p = 0.02) favoring the early group. Consistently, post-PCI tissue perfusion parameters were significantly improved in the early group, as assessed by 60-min ST-segment reduction > or =70% (50% vs. 35%; p = 0.03) and MBG 2 or 3 (79% vs. 58%; p = 0.001). Left ventricular function recovery at 1 month was significantly greater in the early group (mean gain ejection fraction 8 +/- 7% vs. 6 +/- 7%, p = 0.02; mean gain wall motion score index 0.4 +/- 0.3 vs. 0.3 +/- 0.3, p = 0.03). CONCLUSIONS: In patients with AMI treated with primary PCI, early abciximab administration improves pre-PCI angiographic findings, post-PCI tissue perfusion, and 1-month left ventricular function recovery, possibly by starting early recanalization of the infarct-related artery.     

Facilitated primary coronary intervention with abciximab and very low dose of alteplase during off-hours compared with direct primary intervention during regular hours.

In patients with acute myocardial infarction (AMI), the off-hour presentation is one of the major determinants of door-to-balloon delay. Moreover, the nighttime presentation is associated with increased mortality after primary coronary intervention (PCI). The prompt starting of a therapy able to start recanalization of the infarct-related artery before intervention might improve the results of off-hour primary PCI. We compared the outcome of 212 consecutive patients with AMI undergoing either direct or facilitated PCI according to the hour of presentation. Patients arriving off-hours were pretreated with alteplase (20 mg) and abciximab and underwent facilitated PCI. Patients presenting on-hours underwent direct PCI. A basal Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 was observed in 1.0% of patients undergoing direct PCI and in 44% of patients undergoing facilitated PCI (P = 0.001). More patients starting PCI with a TIMI 3 flow achieved a postinterventional fast TIMI frame count (72.0% vs. 38.8% direct PCI group vs. 34.9% facilitated PCI group with basal TIMI 0-2; P = 0.001) and a TIMI perfusion grade 3 (66.0% vs. 38.8% direct PCI group vs. 39.7% facilitated PCI group with basal TIMI 0-2; P = 0.004). Preinterventional TIMI flow grade 3 was associated with a higher gain in left ventricular ejection fraction at 1 month (10.9% +/- 6.4% vs. 7.0% +/- 9.6% direct PCI group vs. 6.1% +/- 6.0% facilitated PCI group with basal TIMI 0-2; P = 0.005). No significant difference was observed in major bleedings, although there was a trend toward a higher risk in the facilitated PCI group. Patients in the facilitated PCI group achieving a basal TIMI 3 flow showed improved myocardial reperfusion and better left ventricular function recovery. Bleeding complications associated with combination therapy remained an important concern.     

Intracoronary thrombectomy improves myocardial reperfusion in patients undergoing direct angioplasty for acute myocardial infarction

OBJECTIVES: We sought to evaluate the effects of mechanical thrombectomy on myocardial reperfusion during direct angioplasty for acute myocardial infarction (AMI). BACKGROUND: Embolization of thrombus and plaque debris may occur during direct angioplasty for AMI. This may lead to distal vessel or side branch occlusion and to obstructions in the microvascular system, resulting in impaired myocardial reperfusion. Mechanical thrombectomy is used to reduce distal embolization. METHODS: Ninety-two patients with AMI and angiographic evidence of intraluminal thrombus were randomized to either intracoronary thrombectomy followed by stenting or to a conventional strategy of stenting. Thrombectomy was performed using the X-Sizer catheter (EndiCOR Inc., San Clemente, California). Myocardial reperfusion was assessed by myocardial blush and ST resolution. RESULTS: Postprocedure Thrombolysis in Myocardial Infarction-3 flow was not different between groups (93.5% vs. 95.7%, p = 0.39). Myocardial blush-3 was observed in 71.7% of patients undergoing thrombectomy and in 36.9% of patients undergoing conventional strategy (p = 0.006). ST-segment resolution >or=50% occurred more often in patients undergoing thrombectomy (82.6% vs. 52.2%, p = 0.001). By multivariate analysis, adjunctive thrombectomy was an independent predictor of blush-3 (odds ratio, 3.27; 95% confidence interval, 1.06 to 10.05; p = 0.039). CONCLUSIONS: Intracoronary thrombectomy as adjunct to stenting during direct angioplasty for AMI improves myocardial reperfusion as assessed by myocardial blush and ST resolution.     

Percutaneous thrombectomy with the RESCUE system in acute myocardial infarction

BACKGROUND: Percutaneous coronary interventions (PCI) in acute myocardial infarction with ST segment elevation (STEMI) are associated with distal coronary embolisation. It may be speculated that percutaneous thrombectomy preceding stent implantation may prevent coronary microcirculation from embolisation. AIM: To assess safety and efficacy of percutaneous thrombectomy in patients with STEMI. METHODS: Seventy two patients with STEMI were randomised to PCI with stent implantation alone (n=32) or percutaneous thrombectomy with the RESCUE system, followed by stent implantation (n=40). Coronary flow in infarct related artery before and after the procedure was assessed using TIMI scale and corrected TIMI frame count - cTFC. Myocardial blood flow was measured using TIMI myocardial perfusion grade - tMPG. The degree of ST segment resolution 60 min after PCI was also assessed. Left ventricular ejection fraction (LVEF) was measured in hospital and three months later. RESULTS: The two groups did not differ with respect to the time from the onset of symptoms to the procedure (236+/-162 min vs 258+/-198 min, NS) or the baseline TIMI, cTFC and tMPG values. An effective thrombectomy procedure was performed in 35 (87%) patients from group B. After the procedure, the number of patients with TIMI 3 grade as well as cTFC values and the proportion of patients with tMPG 3 were similar in both groups (86% vs 85%, NS; 19 vs 21, NS; and 38% vs 54%, NS). The sum of ST segment elevations after the procedure was significantly greater in patients who underwent PCI only compared with patients who had thrombectomy and PCI (6.8+/-5.2 mm vs 3.6+/-2.9 mm, p=0.004). Complete normalisation of ST segment was achieved in 68% of patients treated with thrombectomy and PCI compared with 25% of patients who had PCI only (p=0.005). CK-MB peak values occurred significantly earlier in patients treated with thrombectomy (92.1% vs 66.7% up to 360 min, p=0.01). After 3 months of follow-up, LVEF tended to be greater in patients treated with thrombectomy and PCI than in those who underwent PCI only (55.3+/-14.7% vs 60.3+/-9.2%, NS). CONCLUSIONS: Thrombectomy with the RESCUE system in patients with STEMI is safe and effectively restores patency of infarct related artery. Thrombectomy better improves myocardial perfusion than standard PCI.     

A safe and effective regimen without heparin therapy after successful primary coronary stenting in patients with acute myocardial infarction

Short-term heparin therapy has been administered routinely after primary coronary stenting. However. heparin therapy results in a significantly higher incidence of bleeding and vascular complications. A new therapeutic regimen of ticlopidine and aspirin without further heparin after coronary stenting in patients without AMI has been shown to be safe and reduce the incidence of stent thrombosis. The aim of this study was to evaluate whether a new therapeutic regimen of aspirin and ticlopidine without heparin is safe and effective in patients with acute myocardial infarction (AMI) who have undergone primary coronary stenting and have Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow in the infarct-related artery. Between January 1997 and September 1999, one hundred and fifty two consecutive patients with AMI on Killip score 1 or 2 who underwent primary coronary stenting resulting in TIMI grade 3 flow were enrolled and divided into two groups: Group 1 (n = 95 patients) received aspirin, ticlopidine and further intravenous heparin infusion for 48 hours following primary coronary stenting; Group 2 (n = 57 patients) received only aspirin and ticlopidine without further heparin therapy following primary coronary stenting. No in-hospital major cardiac events were observed in either group. However, the combined incidence of bleeding and vascular complications (27.4% vs 12.3%, p = 0.029) and the need for blood transfusions (9.5% vs 0%, p = 0.013) were significantly higher in Group I patients. Furthermore, hospital stay was also longer in Group I patients (5.8+/-2.4 vs 4.7+/-1.7 days, p = 0.0003). At the 30-day follow-up, there were no differences (1.05% vs 0%, p = 0.63) in the combined incidence of vascular complications and the major cardiac events were similar (1.05% vs 1.75%, p = 0.71) between the groups. The results suggest that further heparin therapy following primary coronary stenting increases the combined incidence of bleeding and vascular complications as well as the need for blood transfusions and prolongs the length of hospital stay without further benefit to those patients with coronary flow restored to TIMI 3 grade flow.     

Predictors of infarct size after primary coronary angioplasty in acute myocardial infarction from pooled analysis from four contemporary trials

Determinates of infarct size in patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) have been incompletely characterized, in part because of the limited sample size of previous studies. Databases therefore were pooled from 4 contemporary trials of primary or rescue PCI (EMERALD, COOL-MI, AMIHOT, and ICE-IT), in which the primary end point was infarct size assessed using technetium-99m sestamibi single-photon emission computed tomographic imaging, measured at the same core laboratory. Of 1,355 patients, infarct size was determined using technetium-99m sestamibi imaging in 1,199 patients (88.5%), at a mean time of 23 +/- 15 days. Median infarct size of the study population was 10% (interquartile range 0% to 23%; mean 14.9 +/- 16.1%). Using multiple linear regression analysis of 18 variables, left anterior descending infarct artery, baseline Thrombolysis In Myocardial Infarction grade 0/1 flow, male gender, and prolonged door-to-balloon time were powerful independent predictors of infarct size (all p <0.0001). Other independent correlates of infarct size were final Thrombolysis In Myocardial Infarction grade <3 flow (p = 0.0001), previous AMI (p = 0.005), symptom-onset-to-door time (p = 0.021), and rescue angioplasty (p = 0.026). In conclusion, anterior infarction, time to reperfusion, epicardial infarct artery patency before and after reperfusion, male gender, previous AMI, and failed thrombolytic therapy were important predictors of infarct size after angioplasty in patients with AMI assessed using technetium-99m sestamibi imaging and should be considered when planning future trials of investigational drugs or devices designed to enhance myocardial recovery.     

Thrombolysis in myocardial infarction myocardial perfusion grade in angiography correlates with myocardial salvage in patients with acute myocardial infarction treated with stenting or thrombolysis

OBJECTIVES: We sought to assess the relationship between the Thrombolysis In Myocardial Infarction (TIMI) myocardial perfusion (TMP) grade and myocardial salvage as well as the usefulness of TMP grade in comparing two different reperfusion strategies. BACKGROUND: The angiographic index of TMP grade correlates with infarct size and mortality after thrombolysis for acute myocardial infarction (AMI). Its relationship to myocardial salvage and its usefulness in comparing different reperfusion strategies are not known. METHODS: We analyzed the TMP grade on angiograms obtained at one to two weeks after treatment in 267 patients enrolled in two randomized trials that compared stenting with thrombolysis in AMI. Patients were classified into two groups: 159 patients with TMP grade 2/3 and 108 patients with TMP grade 0/1. Two scintigraphic studies were performed: before and one to two weeks after reperfusion. The salvage index was calculated as the proportion of the area at risk salvaged by reperfusion. RESULTS: Patients with TMP grade 2/3 had a higher salvage index (0.49 +/- 0.42 vs. 0.34 +/- 0.49, p = 0.01), a smaller final infarct size (15.4 +/- 15.5% vs. 22.1 +/- 16.2% of the left ventricle, p = 0.001), and a trend toward lower one-year mortality (3.8% vs. 8.3%, p = 0.11) than patients with TMP grade 0/1. The relationship between TMP and salvage index was independent of the form of reperfusion therapy. The proportion of patients with TMP grade 2/3 was significantly higher after stenting than after thrombolysis (70.9% vs. 48.1%, p = 0.001). CONCLUSIONS: These findings show that the TMP grade is a useful marker of the degree of myocardial salvage achieved with reperfusion and a sensitive indicator of the efficacy of reperfusion strategies in patients with AMI.     

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.     

Comparison of outcomes of direct stenting versus stenting after balloon predilation in patients with acute myocardial infarction (DIRAMI)

Due to recent advances in stent design, stenting without balloon predilation (direct stenting) has become more extensively used in patients with acute myocardial infarction (AMI). We performed a randomized study with broad inclusion criteria and early randomization after presentation to compare direct stenting with stenting after balloon predilation in patients with AMI. A total of 248 patients was randomized. After exclusion of patients not suitable for stenting, the final study group comprised 217 patients. Direct stenting strategy was feasible in 88% of patients with no meaningful complications. Final Thrombolysis In Myocardial Infarction grade 3 flow (96% vs 94%), final Thrombolysis In Myocardial Infarction myocardial perfusion grade 2 or 3 (68% vs 61%), and average ST-segment resolution after the procedure (49% vs 51%) were similar in the direct stenting and predilation groups, respectively (p = NS). Rate of in-stent restenosis was higher in the direct stenting group (30% vs 16%, p = 0.024), which was due to a worse angiographic result after the procedure. At 5 years, a composite of cardiac death, reinfarction, and target lesion revascularization had occurred in 39% in the direct stenting group and 34% in the predilated group (p = 0.40). In conclusion, although at 5 years clinical outcome did not differ significantly between groups, direct stenting was associated with a higher incidence of in-stent restenosis at 1 year. Direct stenting did not improve epicardial and myocardial reperfusion indexes. Direct stenting strategy should not be recommended in all patients with AMI as an alternative strategy to stenting after predilation.     

Platelet glycoprotein IIb/IIIa inhibition using eptifibatide with primary coronary stenting for acute myocardial infarction: a 30-day follow-up study.

The results of primary coronary stenting for acute myocardial infarction (AMI) have been reported to improve significantly with the concomitant administration of platelet glycoprotein IIb/IIIa inhibitor abciximab. There are, however, no data available with the use of eptifibatide, a more cost-effective, small-molecule GP IIb/IIIa blocker with a shorter half-life. In a prospective multicenter feasibility and efficacy study, we assigned 55 consecutive patients with AMI being taken up for primary stenting to receive eptifibatide just before the procedure (two boluses of 180 microg/kg 10 min apart and a 24-hr infusion of 2 microg/kg/min). Clinical outcomes were evaluated at 30 days after the procedure. The angiographic patency of the vessel with TIMI flow rates, TIMI myocardial perfusion (TMP) grade, and corrected TIMI frame counts were assessed at the end of procedure and before hospital discharge. At 30 days, the primary endpoint, a composite of death, myocardial infarction, and urgent target vessel revascularization (TVR) was seen in 12.7% of patients. The TIMI 3 and TMP grade 3 flow, which was seen in 93% and 86% of patient, respectively, at the end of the procedure, declined to 86% and 78%, respectively (P < 0.05) before hospital discharge. Corrected TIMI frame counts also decreased from 25.7 +/- 7.2 to 22.9 +/- 6.8 (P < 0.05). There were five (9.1%) instances of subacute thrombosis (SAT) presenting as AMI, needing urgent TVR in all, within 3-5 days of the primary procedure. No excessive bleeding complication, directly attributable to the use of eptifibatide, was observed. The study was terminated prematurely because of an unacceptable SAT rate. Administration of eptifibatide along with primary stenting for AMI is associated with a high TIMI 3 and TMP grade 3 flow acutely. However, these flows decline significantly before hospital discharge and lead to a high rate of SAT. The dosage and duration of infusion of eptifibatide in this setting needs further evaluation.     

Early abciximab administration in acute myocardial infarction treated with primary coronary intervention

BACKGROUND: Glycoprotein IIb/IIIa inhibitors improve myocardial reperfusion and clinical outcomes of patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI), but optimal timing of administration remains unclear. In this prospective randomized trial, we evaluated the impact of early abciximab administration on angiographic findings, myocardial salvage and left ventricular function. METHODS AND RESULTS: Fifty-five consecutive patients with first AMI, undergoing primary PCI, were randomized to abciximab administration either in the emergency room (early group: 27 patients) or in the catheterization laboratory after coronary angiography (late group: 28 patients). The primary outcome measures were initial Thrombolysis In Myocardial Infraction (TIMI) grade flow, corrected TIMI frame count and myocardial blush grade as well as salvage index and left ventricular function recovery as assessed by serial scintigraphic scans performed at admission, and 7 days and 1 month after PCI. Angiographic analysis showed a significant difference in initial TIMI grade 3 flow, corrected TIMI frame count and myocardial blush grade favouring early group. Moreover, salvage index and left ventricular function recovery were significantly greater in the early group (P=0.007; and P=0.043, respectively). CONCLUSIONS: In patients with AMI, treated with primary PCI, early abciximab administration improves myocardial salvage and left ventricular function recovery probably by starting early recanalization of the infarct-related artery.     

The effects of prior use of atorvastatin on coronary blood flow after primary percutaneous coronary intervention in patients presenting with acute myocardial infarction

BACKGROUND: Statins exert a variety of favourable effects on the vascular system not directly related to their lipid lowering function known as pleiotropic effects. There are not enough data regarding the effects of prior statin use on coronary blood flow after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). Accordingly, in the present study, we aimed to investigate the effects of prior statin use on coronary blood flow after primary PCI in patients with AMI using the Thrombolysis In Myocardial Infarction (TIMI) frame count method. METHODS: The study population consisted of 200 patients (161 men; mean age=62+/-7 years) referred to cardiology clinics with AMI who subsequently underwent successful primary PCI. The study population was divided into two groups according to statin use before primary PCI. Group 1 consisted of 98 patients (75 men; mean age=63+/-7 years) not taking statin and group 2 consisted of 102 patients (86 men; mean age=61+/-7 years) taking daily dose of at least 40 mg atorvastatin for at least 6 months. Coronary blood flow was determined by TIMI frame count method using the angiographic images obtained just after PCI and stenting. RESULTS: Only mean TIMI frame count was detected to be significantly lower in patients taking at least 40 mg atorvastatin for at least 6 months compared with that of the patients taking no statin (P<0.001). After confounding variables were controlled for, the mean TIMI frame count of patients in group 2 was significantly lower than that of the patients in group 1 (P=0.001). Pain to balloon time and vessel type were detected as important confounding variables of TIMI frame count after analysis of covariances. CONCLUSIONS: Prior statin use may improve coronary blood flow after PCI in patients with AMI, possibly by its beneficial effects on microvascular function.