High Dose Bolus Heparin as Initial Therapy Before Primary Angioplasty for Acute Myocardial Infarction: Results of the Heparin in Early Patency (HEAP) Pilot Study

Objectives. We sought to determine the effect of high dose intravenous bolus heparin on early coronary patency before primary angioplasty.Background. Early coronary angiography after thrombolysis for acute myocardial infarction has shown better patency when intravenous heparin is used as an adjunct. The present study explores whether heparin alone can induce reperfusion.Methods. In the Heparin in Early Patency (HEAP) pilot study, 108 patients with signs and symptoms of acute myocardial infarction <6 h eligible for primary angioplasty received a single intravenous bolus of 300 U/kg of heparin together with aspirin (160 mg chewed) in the emergency room. The median dose of bolus heparin given was 27,000 U. Patency of the infarct-related artery (IRA) was assessed by coronary angiography at a median of 85 min after the heparin bolus.Results. In 55 patients (51%, 95% confidence interval 38% to 64%), Thrombolysis in Myocardial Infarction (TIMI) flow grade 2 or 3 was observed at 90 min: TIMI flow grade 3 in 33 patients (31%); TIMI flow grade 2 in 22 (20%). Thirty-two (64%) of 50 patients with symptoms ≤2 h had TIMI flow grade 2 or 3 versus 23 (40%) of 58 patients with symptoms >2 h (p = 0.02). No significant bleeding was seen. Two patients (2%) died in the hospital. The patency results obtained in patients treated with the high dose bolus heparin were compared with those in 108 patients from a large primary angioplasty database, who were treated with standard therapy, including aspirin but not intravenous heparin, and were matched for clinical and angiographic characteristics with the HEAP pilot study patients. They showed an 18% patency rate (p < 0.001) of the IRA (TIMI flow grade 3 in 9%, TIMI flow grade 2 in 9%) before primary angioplasty.Conclusions. Early therapy with high dose heparin is associated with full coronary reperfusion in a considerable number of patients with acute myocardial infarction, especially in those treated early (<2 h). This simple, inexpensive, probably safe and easily antagonizable treatment may be an attractive first treatment of acute myocardial infarction both before and during the hospital stay in conjunction with primary angioplasty.     

Effects of direct stenting on epicardial and myocardial perfusion in patients with acute ST segment elevation myocardial infarction

BACKGROUND: Results of studies comparing direct stenting (DS) with conventional stenting (CS) after balloon predilatation in patients with acute myocardial infarction (MI) have been reported in the past, however they are conflicting. There are only few randomised studies that aim to answer whether DS improves epicardial and myocardial patency. AIM: To assess the effects of DS on epicardial and myocardial patency in patients with acute MI. METHODS: Consecutive patients with acute MI were randomised either to DS or CS strategy. Clinical exclusion criteria were as follows: clinical and electrocardiographic features of reperfusion, pulmonary oedema, cardiogenic shock, contradictions to coronarography, allergy to aspirin, ticlopidine, clopidogrel, heparin and stainless steel. Angiographic exclusion criteria were as follows: lesion <50% with correct patency in the infarct-related artery (IRA), lesion in the left main coronary artery, previously performed percutaneous coronary intervention in the target vessel, diameter of the IRA <2 mm or >4 mm. We assessed epicardial patency according to the TIMI (thrombolysis in myocardial infarction) scale and myocardial patency according to the TMPG (TIMI myocardial perfusion grade) scale. In addition, we analysed ST segment resolution in 12-lead electrocardiography (ECG). The ECG was performed before and 30 minutes after PCI. RESULTS: We analysed 300 consecutive patients with acute ST segment elevation MI. After exclusion of patients not suitable for the study design, the DS group comprised 110 patients and the CS group - 107 patients. Clinical and angiographic results were similar in both groups. Initial TIMI 0 (48.2% vs. 43.0%), initial TIMI 3 (31.8% vs. 28.0%), initial TMPG 0-1 (77.3% vs. 78.5%), final TIMI 3 (95.5% vs. 93.5%) and final TMPG 2-3 (68.2% vs. 60.8%) were similar in the DS and CS groups, respectively (p=NS). The incidence of no-reflow phenomenon was comparable in both groups (4.5% vs. 6.5%, NS). The inclusive rate of no-reflow phenomenon plus worsening patency in the IRA were 6.4% vs. 10.3% in the DS and CS groups respectively. The ST segment resolution > or = 50% was 58.1% in the DS group and 56.1% in the CS group (NS). CONCLUSIONS: Direct stenting does not significantly improve epicardial and myocardial patency in an unselected group of patients with acute ST segment elevation MI.     

Effects of the early administration of heparin in patients with ST-elevation myocardial infarction treated by primary angioplasty.

BACKGROUND: The effect of adjunctive heparin for primary angioplasty in patients with ST-elevation myocardial infarction (STEMI) is not well established, so the authors investigated the effect of early heparin administration in the emergency room (ER) on initial patency of the infarct-related artery (IRA) and on the clinical outcome in STEMI patients. METHODS AND RESULTS: One hundred and twenty consecutive patients who presented with STEMI less than 12 h from pain onset and who were eligible for primary percutaneous coronary intervention were allocated to an early heparin group (heparin administered in ER) or a late heparin group (heparin administered after angiography). In the early heparin group, unfractionated heparin (60 U/kg bolus IV, then 14 U . kg(-1) . h(-1) IV infusion) or enoxaparin (1 mg/kg bolus SC) were administered 144+/-95 min before angioplasty. No significant differences in baseline characteristics were observed between the early heparin group (n=56) and the late heparin group (n=64). However, initial Thrombolysis In Myocardial Infarction (TIMI) flow grade in the IRA was significantly different between the 2 groups (frequency of TIMI 0/1/2/3; 48/4/7/41% vs 70/8/11/11%, early vs late respectively, p=0.002). TIMI 2 or 3 flow was significantly more frequent in the early heparin group than in the late heparin group (48% vs 22%, p=0.002). However, no significant differences were noted between the 2 groups in terms of in-hospital major adverse cardiac events (7% vs 11%, p=0.472) and TIMI major bleeding (2% vs 3%, p=0.639). CONCLUSIONS: In STEMI patients, early heparin therapy administered in the ER improves coronary patency, despite not reaching clinical benefit.     

Benefit of coronary reperfusion before intervention on outcomes after primary angioplasty for acute myocardial infarction

Primary percutaneous transluminal coronary angioplasty has become the preferred reperfusion strategy for acute myocardial infarction in most institutions with interventional facilities and experienced operators. The benefit of establishing coronary reperfusion, with or without pharmacologic therapy, before primary angioplasty has not been established. Consecutive patients (n = 1,490) with acute myocardial infarction treated with aspirin and heparin followed by primary percutaneous transluminal coronary angioplasty were followed for 13 years. Follow-up angiography was obtained in 737 patients at 7.7 months. Thrombolysis In Myocardial Infarction (TIMI) 2 to 3 flow in the infarct artery at initial angiography was present in 18.3% of patients, and TIMI 0 to 1 flow in 81.7% of patients. Baseline variables were similar between the 2 groups, except patients with initial TIMI 2 to 3 flow had significantly less cardiogenic shock (1.7% vs 9.4%, p <0.0001) and a lower incidence of depressed ejection fraction <40% (12.6% vs 19.9%, p = 0.007). Procedural success was better in patients with initial TIMI 2 to 3 flow (97.4% vs 93.8%, p = 0.02), and catheterization laboratory events were less frequent. Patients with initial TIMI 2 to 3 flow had lower peak creatine kinase values (1,328 vs 2,790 IU/L, p <0.0001), higher acute ejection fraction (54.3% vs 51.6%, p = 0.05), higher late ejection fraction (59.2% vs 54.9%, p = 0.004), and lower 30-day mortality (4.8% vs 8.9%, p = 0.02). These data indicate that when reperfusion occurs before primary angioplasty, outcomes are strikingly better with less cardiogenic shock, improved procedural outcomes, smaller infarct size, better preservation of left ventricular function, and reduced mortality. This should encourage new strategies to establish reperfusion before "primary" angioplasty with "catheterization laboratory friendly" platelet inhibitors and/or low-dose thrombolytic drugs.     

High dose heparin as pretreatment for primary angioplasty in acute myocardial infarction: the Heparin in Early Patency (HEAP) randomized trial

OBJECTIVES: In the Heparin in Early Patency (HEAP) pilot study a beneficial effect of high-dose heparin on early patency in acute myocardial infarction (MI) was observed in a matched-control study. BACKGROUND: High dose bolus intravenous injection of heparin may achieve lysis of coronary thrombi and could enhance early patency of the infarct related vessel in patients with MI scheduled for primary angioplasty. METHODS: Before primary angioplasty, 584 patients with MI entered an open randomized trial of high dose (300 IU/kg) or low dose (0 or 5,000 IU) heparin. Of the 584 patients, 299 were randomized to high dose and 285 patients to low dose heparin. RESULTS: Thrombolysis In Myocardial Infarction (TIMI) flow grade 2 or 3 was observed before primary angioplasty in 65 patients (22%) in the high dose group and 60 patients (21%) in the low dose heparin group (p > 0.1), whereas TIMI flow grade 3 was observed in 38 (13%) and 24 patients (9%), respectively (p = 0.11). There were no differences in the clinical end points between the two groups. There were no hemorrhagic strokes, while 10% of the patients in the high dose group required blood transfusion versus 6% in the low dose/no heparin group (p = 0.07). No subsets of patients showed beneficial effects of high dose heparin, such as patients with longer delay between heparin administration and diagnostic angiogram or patients with short delay between symptom onset and admission. CONCLUSIONS: There is no benefit of high dose bolus heparin on early patency compared with no or low dose heparin.     

Prehospital fibrinolysis with dual antiplatelet therapy in ST-elevation acute myocardial infarction: a substudy of the randomized double blind CLARITY-TIMI 28 trial

Background Fibrinolytic therapy for acute ST-elevation myocardial infarction (STEMI) is frequently limited by delays in administration and by incomplete reperfusion or reocclusion of the infarct-related artery. Intensified prehospital management of STEMI may shorten time to treatment and improve outcomes. Methods We carried out a prospective substudy in 11 ambulance systems in 216 of the 3,491 patients with STEMI who were enrolled in the CLARITY-TIMI 28 trial. They were randomized in the ambulance to clopidogrel (n = 109) or placebo (n = 107) along with fibrinolysis, aspirin, and heparin. The primary endpoint was the composite of an occluded infarct-related artery (TIMI flow grade 0 or 1), or death or recurrent myocardial infarction before angiography. Results All patients received a fibrin-specific lytic and the baseline characteristics in both groups were comparable. The incidence of the primary endpoint was 16.5% in the clopidogrel-treated and 27.1% in the placebo patients (adj OR 0.62, 95% CI 0.31–1.21, p = 0.16), an effect that was consistent with the effects seen in the in-hospital patients in the main CLARITY-TIMI 28 trial. Prehospital clopidogrel therapy reduced the incidence of an occluded infarct-related artery on the predischarge angiogram (11.8% vs. 22.3%, adj OR 0.52, 95% CI 0.24–1.13, p = 0.10). The 30-day incidence of cardiovascular death, recurrent MI or recurrent myocardial ischemia requiring urgent revascularization was 12.8% vs. 14.0% (adj OR 1.07, 95% CI 0.48–2.39, p = 0.87). Early TIMI major bleeding occurred in no clopidogrel patients compared with two placebo patients (1.9%). Conclusions Addition of clopidogrel to medical reperfusion of STEMI with fibrinolysis, heparin, and aspirin before reaching the hospital is feasible in medically equipped ambulances without an apparent increase in bleeding. Furthermore, prehospital clopidogrel tended to show better early coronary patency compared to placebo, a result consistent with that observed in patients randomized in-hospital in the CLARITY-TIMI 28 trial.     

C-reactive protein on admission and the success of thrombolytic therapy with streptokinase: is there any relation?

BACKGROUND: Recent evidence has demonstrated that inflammation plays a major role in the initiation and progression of atheroma plaques. C-reactive protein (CRP) is shown to have prognostic significance in acute coronary syndromes. We investigated the influence of CRP levels before thrombolytic therapy on infarct-related artery (IRA) patency and the degree of residual stenosis. METHODS: 45 consecutive patients with a first attack of acute myocardial infarction (MI) who underwent streptokinase therapy and subsequently coronary angiography were enrolled into the study. Patients were divided into 2 groups according to the level of CRP on admission. RESULTS: Serum CRP levels were > or =0.5 mg/dL in 26 patients (Group-I) and <0.5 mg/dL in 19 patients (Group-II). The patency of IRA (TIMI-2 and 3) evaluated at 90th minute after the initiation of thrombolytic therapy was similar between the two groups (62% vs. 68%, p>0.05). However, the presence of TIMI-3 flow was significantly lower and TIMI-2 flow was higher in Group-I as compared to Group-II (12% vs. 53%, p=0.003 and 50% vs. 16%, p=0.018 respectively). Additionally, among patients with patent IRA, the degree of residual stenosis was significantly higher in Group-I (80 +/- 14% vs. 68 +/- 15%, p=0.032). CONCLUSION: High serum CRP levels on admission in patients within 6 hours after the start of acute ST-segment elevation MI are associated with lower TIMI flow grades and higher residual stenosis of IRA after intravenous streptokinase. Our observations imply that patients with higher CRP levels on admission require closer follow-up during and after acute MI.     

Comparative analysis of reperfusion time in primary angioplasty vs thrombolysis. Success vs time

We studied 398 patients with diagnosis of acute myocardial infarction who arrived within the first six hours of symptom onset that were treated with thrombolysis or primary angioplasty, they were divided in two groups: Group 1 (n = 198), those treated with 1.5 million U of streptokinase over 60 min and Group 2 (n = 200), those treated with primary angioplasty. In Group 1 the "pain-door" time was 3.7 +/- 1.7 hs vs 3.8 +/- 2.4 hs in group 2 (p = NS). The "door-needle" time was 48 +/- 12 min. compared with the "door-balloon" time of 84 +/- 30 min (p < 0.001). In Group 1, 154 (77.6%) of the patients had clinical of reperfusion after thrombolysis, 58 of them underwent coronary angiography and had an infarct related artery (IRA) patency rate of 45.3%. In Group 2 the IRA patency rate was 85.5% (p < 0.005). Conclusion: Thrombolysis was achieved in a lesser period of time but our findings showed that primary angioplasty was more effective obtaining a TIMI 3 flow.     

Angiographic morphologic features of infarct-related arteries and timely reperfusion in acute myocardial infarction: predictors of slow-flow and no-reflow phenomenon

BACKGROUND: Growing evidence suggests that no-reflow reperfusion after direct percutaneous coronary intervention (d-PCI) is associated with an unfavorable clinical outcome. The purpose of this study was to evaluate whether prerevascularization angiographic morphologic features of infarct-related arteries (IRAs) and timely reperfusion could convey information on slow-flow (Thrombolysis In Myocardial Infarction [TIMI] 2 flow) or no-reflow (TIMI grade < or = 1 flow) reperfusion after d-PCI. METHODS AND RESULTS: Between May 1993 and September 2000, d-PCI was performed in 794 consecutive patients with acute myocardial infarction. Coronary blood flow failed to normalize in 120 patients (15.1%). The incidence of failure to achieve TIMI 3 flow in the IRAs was significantly higher in patients with vs those without the following distinctive prerevascularization angiographic morphologic features: cutoff pattern of occlusion in the IRA (52.4% vs 10.3%, p < 0.001), accumulated thrombus (> 5 mm) proximal to the occlusion (37.5% vs 3.4%, p < 0.001), presence of floating thrombus (66.7% vs 12.7%, p < 0.001), persistent dye stasis distal to the obstruction (51.9% vs 13.8%, p < 0.001), reference lumen diameter (RLD) of the IRA > or = 4 mm (46.3% vs 9.6%, p < 0.001), and incomplete obstruction with presence of accumulated thrombus more than three times the RLD of the IRA (51.7% vs 3.9, p < 0.0001). Each of these six angiographic morphologic features indicated "high-burden thrombus formation." Multiple stepwise logistic regression analysis demonstrated that each of six angiographic morphologic features was an independent predictor of combined slow-flow and no-reflow phenomenon in the IRAs after d-PCI (p < 0.05). In contrast, early reperfusion time (< 240 min, p = 0.0017), prerevascularization TIMI flow grade > or = 2 (p = 0.0006), and the taper pattern of occlusion in the IRA (p = 0.0284) were independent predictors of freedom from slow-flow or no-reflow phenomenon in the IRAs after d-PCI. The 30-day overall mortality was 8.7% (69 of 794 patients). The 30-day mortality was significantly higher in patients with combined slow-flow and no-reflow phenomenon than in patients with normal coronary blood flow after d-PCI (27.5% vs 5.3%, p < 0.001). CONCLUSIONS: Early reperfusion reduces the incidence of slow-flow or no-reflow phenomenon in the IRA and overall 30-day mortality. The specific angiographic morphologic features in the IRAs can be used as a simple and efficacious method to predict slow-flow or no-reflow phenomenon. These findings provide apparently clinically useful information for the selection of patients who are potential candidates for subsequent prepercutaneous coronary intervention adjunctive therapy.     

Abciximab in the treatment of acute myocardial infarction eligible for primary percutaneous transluminal coronary angioplasty. Results of the Glycoprotein Receptor Antagonist Patency Evaluation (GRAPE) pilot study.

OBJECTIVES: We sought to study the effect of early infusion of abciximab on coronary patency before primary angioplasty in patients with acute myocardial infarction. BACKGROUND: Glycoprotein IIb/IIIa antagonists have proved to be effective in reducing ischemic events associated with coronary angioplasty. The present study explores whether abciximab alone, without administration of thrombolytic therapy, may induce reperfusion in patients with acute myocardial infarction. METHODS: In the Glycoprotein Receptor Antagonist Patency Evaluation pilot study 60 patients with less than 6 h signs and symptoms of acute myocardial infarction eligible for primary angioplasty received in the emergency room a bolus of abciximab 250 microg/kg followed by a 12-h infusion of 10 microg/min. All patients were also treated with an oral dose of 160 mg aspirin and 5,000 IU of heparin intravenously. As soon as possible a diagnostic angiography was performed to evaluate the patency of the infarct-related artery. RESULTS: The median time between onset of symptoms and the administration of the abciximab bolus was 150 min (range 45 to 345), and the median time between abciximab bolus and first contrast injection in the infarct-related artery was 45 min (range 10 to 150). In 24 patients (40%, 95% confidence interval 28% to 52%) Thrombolysis in Myocardial Infarction (TIMI) flow grade 2 or 3 was observed at a median time of 45 min (range 10 to 150) after abciximab bolus; TIMI flow grade 3 was observed in 11 patients (18%, 95% confidence interval 9% to 28%). There was no difference in percentage of TIMI flow grade 2 or 3 between patients who received abciximab within 2.5 h after onset of symptoms or thereafter. CONCLUSIONS: Abciximab therapy given in the emergency room in patients awaiting primary angioplasty is associated with full reperfusion (TIMI flow grade 3) in about 20% and with TIMI flow grade 2 or 3 in about 40% of the patients at a median time of 45 min. These figures are higher than those in primary angioplasty trials without such pretreatment. Randomized controlled trials of very early infusion of abciximab, either prehospital or in-hospital, in patients eligible for angioplasty are warranted.     

Relationship of admission haematological indices with infarct-related artery patency in patients with acute ST-segment elevation myocardial infarction treated with primary angioplasty

OBJECTIVE: Mean platelet volume (MPV), a marker for platelet reactivity, and white blood cell count (WBC-C), a marker for inflammation, have been shown to be predictive of unfavourable outcomes among survivors of ST elevation myocardial infarction (STEMI). The relationship of admission MPV and WBC-C with infarct-related artery (IRA) patency is not clear. We aimed to evaluate the value of admission MPV and WBC-C for the prediction of IRA patency, in patients with acute STEMI treated with primary percutaneous coronary intervention. METHODS: Blood samples were obtained on admission in 351 STEMI patients. The patients who had thrombolysis in myocardial infarction (TIMI) 3 flow in initial angiography constituted the IRA patent group and others having less than TIMI 3 flow constituted the IRA occluded group. RESULTS: In 16% of the patients, IRAs were found to be patent on initial angiography. Patients in the IRA occluded group had higher admission MPVs (9.3+/-1.2 vs. 8.6+/-1.3 fl, P<0.001) and higher WBC-C (13.3+/-4.8 vs. 11.0+/-2.9, P=0.002) compared with patients in the patent IRA group. In regression analysis, WBC-Cs [beta, 0.131; odds ratio (OR), 1.140; 95% confidence interval (CI), 1.043-1.245, P=0.004)] and MPV (beta, 0.519; OR, 1.680; 95% CI, 1.206-2.339, P=0.002) were found to be independent predictors of occluded IRA. The best cutoff value of MPV for predicting an occluded IRA was determined to be 8.55 fl with a sensitivity of 74% and a specificity of 60%. CONCLUSION: MPV and WBC-C at admission might be valuable in the prediction of IRA patency and in planning the need for adjunctive therapy to improve outcomes in patients with STEMI undergoing percutaneous coronary intervention.     

Importance of a patent infarct-related artery for hospital and late survival after direct coronary angioplasty for acute myocardial infarction.

The importance of a patent infarct-related artery (IRA) for hospital and late survival was examined in 383 patients with acute myocardial infarction treated with direct coronary angioplasty. At hospital discharge, 317 of 348 patients (91%) had a patent IRA and mean follow-up left ventricular (LV) ejection fraction (EF) was 58%. Cardiac survival after hospital discharge at 1, 3 and 6 years was 99, 95 and 90%. Patency of the IRA was the most important determinant of hospital mortality: patent versus occluded IRA, 5 vs 39% mortality, p less than 0.001. Follow-up LVEF was the most important determinant of late cardiac mortality: follow-up LVEF greater than or equal to 45 versus less than 45%, 2 versus 24% mortality, p less than 0.001. Patency of the IRA was not a significant predictor of late cardiac mortality in the group as a whole: patent versus occluded IRA, 4.7 versus 6.5% mortality, p = 0.67. In the subgroup of patients with depressed initial LVEF less than 45%, patency was a significant predictor of late cardiac mortality: patent versus occluded IRA, 9.2 versus 40% mortality, p = 0.03. Patients with a patent IRA had better recovery of LV function than patients with an occluded IRA (follow-up LVEF 58.5 versus 47.6%, p less than 0.001). When late cardiac mortality was adjusted for differences in follow-up LVEF, patency was no longer a significant predictor of late mortality. Our results indicate patency of the IRA is the most important determinant of hospital survival, and LV function (measured after recovery) is the most important determinant of late cardiac survival.(ABSTRACT TRUNCATED AT 250 WORDS)     

A matched comparison of the combination of prehospital thrombolysis and standby rescue angioplasty with primary angioplasty

This study sought to assess the rate of acute Thrombolysis In Myocardial Infarction (TIMI) trial grade 3 patency that can be achieved with the combination of prehospital thrombolysis and standby rescue angioplasty in acute myocardial infarction. No large angiographic study has been performed after prehospital thrombolysis to determine the 90-minute TIMI 3 patency rate in the infarct-related artery. Hospital outcome and artery patency were compared to 170 matched patients treated with primary angioplasty. Prehospital thrombolysis was applied 151+/-61 minutes after the onset of pain in 170 patients (56+/-12 years, 86% men), using recombinant tissue-type plasminogen activator, streptokinase, or eminase. Emergency 90-minute angiography was performed in every case. All patients in whom thrombolysis failed underwent rescue angioplasty. After thrombolysis alone, TIMI grade 3 flow in the infarct-related artery was observed in 108 patients (64%), TIMI grade 2 in 12 (7%), and TIMI grade 0 or 1 in 50 (29%). Rescue angioplasty was successful in 47 of 50 attempts. Overall, TIMI 3 patency was achieved in 91%, and additionally TIMI 2 flow in 7% of patients, an average of 113+/-39 minutes after thrombolysis and 55+19 minutes after admission. Therefore, < 2 hours after thrombolysis, only 2% of patients had persistent occlusion (TIMI 0 or 1) of the infarct-related artery. In-hospital mortality was 4% overall (7 of 170), and 3% in the 155 patients in whom TIMI 3 was obtained during the acute phase. Severe hemorrhagic complications occurred in 14 patients (8%) with 2 fatal cerebral hemorrhages (7% of patients required transfusions). The matched comparison with primary PTCA showed no significant difference in hospital outcome. Combined prehospital thrombolysis, 90-minute angiography, and rescue angioplasty yield a high rate of acute TIMI 3 patency rate early after thrombolysis and hospital admission. A randomized, prospective comparison between these 2 reperfusion strategies may be now warranted.     

The Prehospital Electrocardiogram in Acute Myocardial Infarction: Is Its Full Potential Being Realized?

Objectives. This study sought to examine the management and subsequent outcomes of patients with a prehospital electrocardiogram (ECG) in a large, voluntary registry of myocardial infarction.Background. The prehospital ECG has been proposed as a means of rapidly identifying patients with acute myocardial infarction who might be eligible for reperfusion therapy.Methods. The characteristics and outcomes of patients with a prehospital ECG were compared with those without a prehospital ECG in the National Registry of Myocardial Infarction 2 data base. Included in the analysis were those patients who presented to the hospital within 12 h of an acute myocardial infarction. Excluded were patients with an in-hospital infarction, transferred-in referrals and self-transported patients.Results. Prehospital ECGs were obtained in 3,768 (5%) of 66,995 National Registry of Myocardial Infarction 2 patients meeting study criteria. Median time from myocardial infarction symptom onset until hospital arrival was longer among those having a prehospital ECG (152 vs. 91 min, p < 0.001). However, once in the hospital, the prehospital ECG group experienced a shorter median time to the initiation of either thrombolysis (30 vs. 40 min, p < 0.001) or primary angioplasty (92 vs. 115 min, p < 0.001). The prehospital ECG group was more likely to receive thrombolytic therapy (43% vs. 37%, p < 0.001) and to undergo primary angioplasty (11% vs. 7%, p < 0.001). Also, the prehospital ECG group was more likely to undergo coronary arteriography (55% vs. 40%, p < 0.001), angioplasty (24% vs. 16%, p < 0.001) or bypass surgery (10% vs. 6%, p < 0.001). The in-hospital mortality rate was 8% in patients with a prehospital ECG and 12% in those without a prehospital ECG (p < 0.001). After adjusting for baseline covariates utilizing multiple logistic regression analysis, this mortality difference remained statistically significant (odds ratio 0.83, 95% confidence interval 0.71 to 0.96, p = 0.01).Conclusions. The prehospital ECG is infrequently utilized for diagnosing myocardial infarction, and among patients with a prehospital ECG, is associated with a longer time from symptom onset to hospital arrival. Despite these shortcomings, the prehospital ECG is a test that may potentially influence the management of patients with acute myocardial infarction through wider, faster in-hospital utilization of reperfusion strategies and greater usage of invasive procedures, factors that may possibly reduce short-term mortality. Efforts to implement the prehospital ECG more widely and more rapidly may be indicated.(J Am Coll Cardiol 1997;29:498–505)     

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.     

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.     

A randomized trial comparing primary angioplasty with a strategy of short-acting thrombolysis and immediate planned rescue angioplasty in acute myocardial infarction: the PACT trial. PACT investigators. Plasminogen-activator Angioplasty Compatibility Trial

OBJECTIVES

The study evaluated the efficacy and safety of a short-acting reduced-dose fibrinolytic regimen to promote early infarct-related artery (IRA) patency during the inherent delay experienced by infarct patients referred for angioplasty as the principal recanalization modality.

BACKGROUND

Previous approaches using long-acting, full-dose thrombolytic infusions rarely showed benefit, but they did increase adverse event rates.

METHODS

Following aspirin and heparin, 606 patients were randomized to a 50-mg bolus of recombinant tissue-type plasminogen activator (rt-PA) (alpha half-life 4.5 min) or to placebo followed by immediate angiography with angioplasty if needed. The end points included patency rates on catheterization laboratory (cath lab) arrival, technical results when PTCA (percutaneous transluminal coronary angioplasty) was performed, complication rates, and left ventricular (LV) function by treatment assignment and time to restored patency following angioplasty.

RESULTS

Patency on cath lab arrival was 61% with rt-PA (28% Thrombolysis in Myocardial Infarction trial [TIMI]-2, 33% TIMI-3), and 34% with placebo (19% TIMI-2, 15% TIMI-3) (p = 0.001). Rescue and primary PTCA restored TIMI-3 in closed arteries equally (77%, 79%). No differences were observed in stroke or major bleeding. Left ventricular function was similar in both treatment groups, but convalescent ejection fraction (EF) was highest with a patent IRA (TIMI-3) on cath lab arrival (62.4%) or when produced by angioplasty within an hour of bolus (62.5%). However, in 88% of angioplasties, the delay exceeded 1 h: convalescent EF 57.3%.

CONCLUSIONS

Tailored thrombolytic regimens compatible with subsequent interventions lead to more frequent early recanalization (before cath arrival), which facilitates greater LV function preservation with no augmentation of adverse events.     

Patient outcomes after fibrinolytic therapy for acute myocardial infarction at hospitals with and without coronary revascularization capability

OBJECTIVES: This study evaluated clinical outcomes in patients with acute myocardial infarction (MI) treated with fibrinolytic therapy in hospitals with and without coronary revascularization capability. BACKGROUND: Patients with MI may have better outcomes when admitted to certain hospitals with coronary revascularization capability. Development of regional heart care centers for the treatment of MI has been proposed. METHOD: We performed a retrospective analysis of 25,515 U.S. patients enrolled in the Global Use of Streptokinase and TPA (alteplase) for Occluded Coronary arteries (GUSTO)-I trial. Outcomes of patients admitted to hospitals with and without coronary revascularization capability were analyzed. We also analyzed patients who remained in hospitals without coronary revascularization capability compared with those transferred to hospitals with revascularization capability. RESULTS: Baseline characteristics and complications were similar between patients in the two hospital types. Patients in hospitals with coronary revascularization capability more often underwent cardiac catheterization (78.1% vs. 59.2%; p < 0.001), angioplasty (34.6% vs. 22.6%; p < 0.001), or bypass surgery (14.1% vs. 10.4%; p < 0.001) but had a similar adjusted 30-day (odds ratio [OR] 0.91, 95% confidence interval [CI] 82 to 1.02) and one-year (OR 0.98, 95% CI 0.90 to 1.07) mortality. Forty percent of patients admitted to hospitals without revascularization capability were transferred, with 94% of transfer patients undergoing angiography. Almost 80% of transfers occurred >48 h after hospital admission. CONCLUSION: Patients receiving fibrinolytic therapy for acute MI admitted to hospitals without coronary revascularization capability appear to have outcomes similar to those of patients admitted to hospitals with such capability when aspirin and beta-adrenergic blocking agents are given appropriately and transfer is available for angiography and angioplasty as needed.     

Impact of tirofiban on angiographic morphologic features of high-burden thrombus formation during direct percutaneous coronary intervention and short-term outcomes

BACKGROUND: Recently, we demonstrated that angiographic morphologic features of high-burden thrombus formation are independent predictors of combined slow flow (ie, Thrombolysis in Myocardial Infarction [TIMI] grade 2) and no reflow (ie, or = 4.0 mm (p = 0.001), were independent predictors of combined slow flow and no reflow. In stratified analysis, the rates of slow flow and no reflow after d-PCI rose rapidly as the number of independent predictors increased (0 predictors, 3.8%; 1 predictor, 29.0%; and 2 predictors, 70.6%). The overall 30-day mortality rate was 6.7%. The mortality rate was significantly higher in patients with TIMI flow lower than or equal to grade 2 than in those with TIMI grade 3 flow (15% vs 1.3%, respectively; p = 0.003). CONCLUSIONS: Tirofiban did not provide additional clinical benefits when administered in conjunction with d-PCI for AMI, even in the subgroup of patients with a high-burden thrombus. Those distinct angiographic morphologic features of high-burden thrombus formation remained as independent predictors of combined slow flow and no reflow after d-PCI, and were independent of the use of tirofiban.     

Postinfarctional remodeling: increased dye intensity in the myocardial risk area after angioplasty of infarct-related coronary artery is associated with reduction of ventricular volumes

OBJECTIVES: We sought to evaluate if angiographic dye videointensity of the risk area during percutaneous transluminal coronary angioplasty (PTCA) of the infarct-related artery (IRA) relates to remodeling. BACKGROUND: Poor reflow after myocardial infarction (MI) predicts worse ventricular remodeling. METHODS: Fifty-three patients with a first anterior MI and isolated disease of the left anterior descending (LAD), who underwent "primary" (n = 14), "rescue" (n = 7) or "late" (after 10 +/- 4 days, n = 32) PTCA, were retrospectively selected. In 10 patients prospectively collected, we assessed Doppler flow velocities and Doppler flow reserve (DFR), relating them to the videointensity technique. Coronary stenosis and TIMI flow were determined, and echocardiographic volumes (end-diastolic and end-systolic volume indexes) and regional asynergy were computed before hospital discharge (baseline) and at six months. Assuming higher peak videointensity reflects greater myocardial blood volume, a 1- to 5-point (poor-optimal) perfusion scale was devised. RESULTS: The correlation of Doppler peak velocity and DFR with videointensity was significant (r = 0.58, p = 0.007 and r = 0.71, p < 0.001, respectively). Patients were subdivided into group A (increased videointensity post-PTCA > or = 1.5 points, n = 29) and group B (unchanged videointensity, n = 24). Analysis of variance showed a time-group interaction for end-diastolic volume index (-4.6 +/- 23% vs. +22 +/- 22%, p = 0.003) and end-systolic volume index (-3.05 +/- 11.1% vs. +4.1 +/- 12.5%, p = 0.027). There was no interaction for changes in LAD stenosis (p = 0.39) and TIMI flow after PTCA (p = 0.27), or regional asynergy at six months (p = 0.31). CONCLUSIONS: Angiographic dye videointensity in the risk area correlates with Doppler peak velocity and DFR, and its increase after PTCA of IRA has a limiting effect on ventricular volumes, independent of coronary stenosis resolution, changes in Thrombolysis In Myocardial Infarction (TIMI) flow or extent of regional asynergy.