Randomized comparison of coronary stenting with balloon angioplasty in selected patients with acute myocardial infarction

Stent placement for non-STRESS/BENESTENT lesions: a critical review

Stenting lesions with favorable characteristics as required for inclusion in the STRESS/BENESTENT trials have yielded superior results to that of PTCA alone. Results for less favorable lesions such as in small vessels, diffuse disease, ostial disease, and saphenous vein grafts are less well established. This review seeks to analyze available data for stent placement in this subset of non-STRESS/BENESTENT lesions.

Facilitated percutaneous coronary intervention for acute myocardial infarction

Facilitated percutaneous coronary intervention is a treatment strategy for acute myocardial infarction in which patients are given medications in the emergency department that open or partially open infarct-related coronary arteries. The patients are then taken to the cardiac catheterization laboratory for early angiography and angioplasty or placement of a coronary artery stent. Preliminary evidence suggests that this treatment strategy may offer outcomes similar to or better than primary angioplasty and superior to solitary fibrinolytic therapy. In addition, the treatment can be started even in hospitals that do not have primary intervention capability. Currently, large-scale clinical trials are assessing the impact of the facilitated percutaneous coronary intervention treatment strategy on the clinical outcomes of patients with acute myocardial infarction.

Absence of preinfarction angina is associated with a risk of no-reflow phenomenon after primary coronary angioplasty for a first anterior wall acute myocardial infarction

BACKGROUND

No-reflow phenomenon after primary coronary angioplasty is associated with poorer left ventricular (LV) function and prognosis after acute myocardial infarction (AMI). The purpose of this study was to determine the clinical significance of preinfarction angina in the no-reflow phenomenon.

METHODS AND RESULTS

A total of 40 patients with first anterior AMI were examined. All patients underwent primary balloon angioplasty or stenting within 12 h of the onset of AMI. No-reflow, defined as TIMI grade 2 flow or less without residual stenosis after angioplasty, was observed in 15 patients. Patients with no-reflow were older (67+/-9 vs. 58+/-10 years, P=0.006) and had a lower incidence of preinfarction angina (7% vs. 48%, P=0.01) than those without no-reflow. Patients with no-reflow had poorer LV function at predischarge and a higher incidence of pump failure, LV aneurysm, malignant ventricular arrhythmias or cardiac death during the hospital course in association with higher peak serum C-reactive protein levels (12.7+/-8.0 vs. 7.1+/-5.5 mg/dl, P=0.02). Multivariate analysis showed that the absence of preinfarction angina was a major independent determinant of no-reflow (RR=17.1, P=0.02).

CONCLUSIONS

The absence of preinfarction angina is more frequently observed in patients with no-reflow. The beneficial effect of preinfarction angina on LV function may be explained, at least in part, by prevention of no-reflow after reperfusion.

[Coronary angioplasty in the acute myocardial infarction: in which patients is it less likely to obtain an adequate coronary reperfusion?]

INTRODUCTION

In patients with acute myocardial infarction treated with primary angioplasty, the inability to achieve successful coronary reperfusion is associated with higher mortality. The objective of the study was to identify which characteristics may predict a lower angiographic success rate in patients with acute myocardial infarction treated with coronary angioplasty.

PATIENTS AND METHODS

The study population is constituted by the 790 patients with acute myocardial infarction that were treated with angioplasty within the 12 hours after the onset of symptoms from 1991 to 1999 at our institution. A successful angiographic result was considered in presence of a residual stenosis < 50% and a TIMI flow 2 or 3 after the procedure.

RESULTS

A successful angiographic result and a final TIMI 3 flow were achieved in 736 (93.2%) and 652 (82.5%) patients, respectively. In-hospital mortality was higher in patients with angiographic failure than in those with angiographic successful result (48 vs. 10%; p < 0.01). Age under 65 (91 vs. 95%; p = 0.02), non smoking (90 vs. 96%; p < 0,01), previous infarction (87 vs. 94%; p < 0.01), angioplasty after failed thrombolysis (83 vs. 94%; p = 0. 02), cardiogenic shock (80 vs. 95%; p < 0.01), undetermined location (67 vs. 93%; p < 0.01), non-inferior location (92 vs. 96%; p = 0.04), left bundle branch block (64 vs. 94%; p < 0.01), multivessel disease (91 vs. 95%; p = 0.02), left ventricular ejection fraction < 0.40 (89 vs. 97%; p < 0.01), no utilization of coronary stenting (90 vs. 96%; p < 0.01), and use of intraaortic balloon counterpulsation pump (82 vs. 95%; p < 0.01) were associated with a lower angiographic success rate. In the multivariable analysis, the following were independent predictors for angiographic failure: left bundle branch block (odds ratio [OR], 12.95; CI 95%, 3.00-53.90), cardiogenic shock (OR, 4.20; CI 95%, 1.95-8.75), no utilization of coronary stent (OR, 3.44; CI 95%, 1.71-7.37), and previous infarction (OR, 2.82; CI 95%, 1.29-5.90).

CONCLUSIONS

Coronary angioplasty allows a successful coronary recanalization in most patients with acute myocardial infarction. Some basic characteristics, however, may identify some subsets in which a successful angiographic result may be more difficult to obtain.

[One-year clinical and angiographic follow-up after primary stenting]

INTRODUCTION AND OBJECTIVES

The late reocclusion or restenosis rate of the infarct related artery is frequent after primary angioplasty. An implanted stent may be able to improve the coronary angioplasty results and long-term outcome of these patients. We present the clinical and angiographic outcome of a cohort of patients treated with primary stenting.

PATIENTS AND METHODS

A group of 74 consecutive patients with acute myocardial infarction treated with primary angioplasty and stenting were followed for one year. An angiographic control was performed at the 6th month of follow-up in 91% of patients to assess the restenosis and reocclusion rates of the infarct-related artery.

RESULTS

There were eight in-hospital deaths and three during follow-up (mortality rate 14.8%) and one non-fatal reinfarction (1.5%). The cumulative rate of recurrent ischemia was 6% at 3 months and 15% at 6 months, without any further increment at one-year follow-up. A new angioplasty was performed in 7 patients and three patients underwent surgical revascularization. Thus 80% of patients after discharge were free of events. The angiographic control showed only one reocclusion of the infarct related artery and a restenosis rate of 27%.

CONCLUSIONS

These results show that primary stenting is an effective procedure in treating non-selected patients with acute myocardial infarction with a low long-term incidence of adverse events and a low restenosis rate.

A comparison of short- and long-term outcomes for balloon angioplasty and coronary stent placement

OBJECTIVES

We sought to compare patient outcomes for coronary stent placement and balloon angioplasty.

BACKGROUND

Since 1994, the number of patients treated only with balloon angioplasty has decreased nationally, whereas the use of coronary stents as an alternative has grown tremendously. The objectives of this study were to compare short- and long-term survival and subsequent revascularization rates for patients undergoing single-vessel balloon angioplasty and coronary stent placement.

METHODS

New York's Coronary Angioplasty Registry was used to identify New York patients undergoing either balloon angioplasty or stent placement between July 1, 1994, and December 31, 1996. Statistical models were used to compare risk-adjusted short- and long-term survival and subsequent coronary artery bypass graft surgery (CABG) and percutaneous coronary interventions (PCIs).

RESULTS

No significant differences were found in adjusted in-patient mortality, but patients who had balloon angioplasty were, on average, 1.36 times more likely to have died at any time during the two-year period after the index procedure (p = 0.003). The adjusted in-patient CABG rate was significantly higher for balloon angioplasty (2.72% vs. 1.66%, p<0.0001), and the adjusted two-year CABG rate was also significantly higher for balloon angioplasty (10.81% vs. 7.25%, p<0.001). The adjusted two-year rate for subsequent PCIs was also significantly higher for balloon angioplasty (19.6% vs. 14.3%, p<0.0001). Although measures were taken to eliminate or minimize the effect of selection bias, it should be noted that patients with stents were healthier at hospital admission than patients who had balloon angioplasty.

CONCLUSIONS

Stent placement is associated with significantly lower risk-adjusted long-term mortality, CABG and subsequent PCI rates, as compared with balloon angioplasty.

A comparison of systematic stenting and conventional balloon angioplasty during primary percutaneous transluminal coronary angioplasty for acute myocardial infarction. STENTIM-2 Investigators

OBJECTIVES

In a multicenter, randomized trial, systematic stenting using the Wiktor stent was compared to conventional balloon angioplasty with provisional stenting for the treatment of acute myocardial infarction (AMI).

BACKGROUND

Primary angioplasty in AMI is limited by in-hospital recurrent ischemia and a high restenosis rate.

METHODS

A total of 211 patients with AMI <12 h from symptom onset, with an occluded native coronary artery, were randomly assigned to systematic stenting (n = 101) or balloon angioplasty (n = 110). The primary end point was the binary six-month restenosis rate determined by core laboratory quantitative angiographic analysis.

RESULTS

Angiographic success (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3 and residual diameter stenosis <50%) was achieved in 86% of the patients in the stent group and in 82.7% of those in the balloon angioplasty group (p = 0.5). Compared with the 3% cross-over in the stent group, cross-over to stenting was required in 36.4% of patients in the balloon angioplasty group (p = 0.0001). Six-month binary restenosis (> or = 50% residual stenosis) rates were 25.3% in the stent group and 39.6% in the balloon angioplasty group (p = 0.04). At six months, the event-free survival rates were 81.2% in the stent group and 72.7% in the balloon angioplasty group (p = 0.14), and the repeat revascularization rates were 16.8% and 26.4%, respectively (p = 0.1). At one year, the event-free survival rates were 80.2% in the stent group and 71.8% in the balloon angioplasty group (p = 0.16), and the repeat revascularization rates were 17.8% and 28.2%, respectively (p = 0.1).

CONCLUSIONS

In the setting of primary angioplasty for AMI, as compared with a strategy of conventional balloon angioplasty, systematic stenting using the Wiktor stent results in lower rates of angiographic restenosis.

Coronary artery stents: review and patient-management recommendations

BACKGROUND

Coronary artery stents are metallic scaffold devices that physically support narrowed coronary arteries to alleviate symptoms of ischemic coronary artery disease. They are placed during invasive procedures similar to that of percutaneous transluminal coronary angioplasty, and patients are maintained with antiplatelet medications to lessen the chances of stent stenosis.

METHODS

The authors provide a brief overview of coronary artery stents and discuss the dental management of patients who have received stents.

CONCLUSIONS

After stent placement, patients usually are maintained with antiplatelet regimens, which may necessitate choosing medications that do not potentiate their effects. Any discussion as to the possible need for antibiotic prophylaxis of patients with stents largely is missing from the literature. Recent literature, however, indicates that antibiotic prophylaxis, if required, may only be needed during the first few weeks after stent placement.

CLINICAL IMPLICATIONS

Dental professionals should become knowledgeable about coronary artery stents. Although these devices have a higher success rate than other procedures in alleviating symptoms of ischemic coronary artery disease, some patients are still at risk of experiencing significant cardiac events.

Triple therapy for acute myocardial infarction: combining fibrinolysis, platelet IIb/IIIa inhibition, and percutaneous coronary intervention

Reperfusion for acute myocardial infarction (MI) has generally been approached in 1 of 2 ways-fibrinolysis or primary angioplasty. Although fibrinolysis is widely available and has been shown to reduce mortality and improve left ventricular function, its disadvantages include hemorrhage, failure to reperfuse in up to 40% of patients, and early reocclusion in up to 10% of patients. Alternatively, primary angioplasty offers the advantages of anatomic definition, the potential for higher rates of reperfusion, and a lower rate of intracranial hemorrhage. Recently, a better understanding of platelet physiology and its inhibition, and advances in mechanical revascularization with stents have led to combined approaches (fibrinolytic agents, glycoprotein IIb/IIIa inhibitors, and percutaneous coronary interventions [PCI]). Faciliated PCI, the use of planned PCI after pharmacologic reperfusion therapy, has the best potential to fuse the best aspects of thrombolysis and primary angioplasty. This article reviews recent advances and trials studying use of these combinations.

Effect of glycoprotein IIb/IIIa receptor blockade with abciximab on clinical and angiographic restenosis rate after the placement of coronary stents following acute myocardial infarction

OBJECTIVES

In the Intracoronary Stenting and Antithrombotic Regimen-2 trial (ISAR-2), we sought to investigate the effect of abciximab on angiographic and clinical restenosis after stenting following acute myocardial infarction (AMI). We also intended to assess the impact of abciximab on clinical outcome in this setting.

BACKGROUND

It is unclear whether abciximab reduces neointima formation after stenting. Such an effect may be particularly prominent in thrombus-containing lesions.

METHODS

Patients undergoing stenting within 48 h after onset of AMI were randomly assigned to receive either standard-dose heparin or abciximab plus reduced-dose heparin. Of 401 patients randomized, 366 without 30-day adverse events were eligible for six-month angiographic follow-up. Scheduled angiography was performed in 80% of these patients.

RESULTS

By 30 days, the composite clinical end point of death, reinfarction, and target lesion revascularization (TLR) was reached in 5.0% of the abciximab group and in 10.5% of the control group (p = 0.038). At one year, absolute reduction in the composite clinical end point by abciximab was still 5.7% but had lost its statistical significance. Our primary end point, late lumen loss, was 1.26+/-0.85 mm with abciximab and 1.21+/-0.74 mm with standard heparin (p = 0.61), and binary angiographic restenosis rates were 31.1% and 30.6%, respectively (p = 0.92).

CONCLUSIONS

In patients undergoing stenting following AMI, abciximab exerted beneficial effects by substantially reducing the 30-day rate of major adverse cardiac events. During one-year follow-up, there was no additional benefit from a reduction in TLR nor did abciximab reduce angiographic restenosis.

Emerging concepts in the management of acute myocardial infarction in patients with diabetes mellitus

Although fibrinolysis has improved survival of patients after myocardial infarction (MI), such therapy is less likely to be administered to patients with diabetes. Furthermore, these patients present later (15 min) than nondiabetics. Moreover, even with the use of early potent fibrinolytic agents, patients with diabetes continued to suffer excessive morbidity and mortality. This finding is not related to the ability of fibrinolytic agents to restore complete reperfusion or increased risk of reocclusion of the infarct-related artery. Instead, the impaired ventricular performance at the noninfarct areas and metabolic derangements during the acute phase of MI may account for the adverse outcome. The efficacy of percutaneous coronary revascularization procedures for treatment of acute MI requires further evaluation. Therapeutic approaches should consider correcting these abnormalities to afford greater survival benefit for this subset of high-risk patients.

Predictors of death and reinfarction at 30 days after primary angioplasty: the GUSTO IIb and RAPPORT trials

BACKGROUND

Thirty-day death among recipients of fibrinolytic therapy for acute myocardial infarction (MI) is tightly correlated with easily obtainable key demographic and clinical parameters such as age, blood pressure, heart rate, and infarct location. Similar data for primary angioplasty are not available.

METHODS AND RESULTS

Data from 2 large, contemporary, primary angioplasty trials were formally combined and analyzed with respect to death and death/repeat MI at 30 days through the use of multivariate logistic regression models. The 1048 patients had a median age of 62 years, and 26% were women. Thirty-eight percent had an anterior infarction. The patients underwent angioplasty at a median delay from symptom onset of 3.8 hours. Death was independently predicted by increasing age (adjusted odds ratio [OR] per decade 2.32, 95% confidence interval [CI] 1.60 to 3.42), whereas a history of smoking (OR 0.29, CI 0.13 to 0.64), Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 after angioplasty (OR vs TIMI <3 0.21, CI 0.10 to 0.45) and higher systolic blood pressure (OR per 10 mm Hg 0.73, CI 0.62 to 0. 87) were associated with lower mortality rates. Death or repeat MI was independently associated with increasing age (OR per decade 1.40, CI 1.13 to 1.76) and anterior location of the index MI (OR 1.89, CI 1.12 to 3.20). TIMI grade 3 flow (OR vs TIMI <3 0.40, CI 0.23 to 0. 68) and higher systolic blood pressure (OR per 10 mm Hg 0.79, CI 0. 71 to 0.89) were associated with a lower incidence of death/repeat MI. Time to angioplasty, heart rate, extent of coronary artery disease, participation in 1 of the 2 trials, and all common coronary risk factors did not significantly predict outcome.

CONCLUSIONS

Death and reinfarction after primary angioplasty are predominantly predicted by age, hemodynamic instability, and the attainment of TIMI 3 flow in the infarct artery.

[The practical clinical guidelines of the Sociedad Española de Cardiología on interventional cardiology: coronary angioplasty and other technics]

Interventional cardiology has had an extraordinary expansion in last years. This clinical guideline is a review of the scientific evidence of the techniques in relation to clinical and anatomic findings. The review includes: 1. Coronary arteriography. 2. Coronary balloon angioplasty. 3. Coronary stents. 4. Other techniques: directional atherectomy, rotational atherectomy, transluminal extraction atherectomy, cutting balloon, laser angioplasty and transmyocardial laser and endovascular radiotherapy. 5. Platelet glycoprotein IIb/IIIa inhibitors. 6. New diagnostic techniques: intravascular ultrasound, coronary angioscopy, Doppler and pressure wire. For the recommendations we have used the classification system: class I, IIa, IIb, III like in the guidelines of the American College of Cardiology and the American Heart Association.

[Results of coronary stenting in acute myocardial infarction]

OBJECTIVE

To describe the angiographic results and the in-hospital clinical outcome of patients with an acute phase of myocardial infarction treated with coronary angioplasty and stent placement.

METHODS

268 patients with myocardial infarction were treated with angioplasty and coronary stenting within in our center 12 hours after the onset of symptoms from January in 1992 to March 1998. 366 stents were placed (1.4 +/- 0.7 per patient), 35% being Palmaz-Schatz, 26% Wiktor, 21% Multi-Link and 18% others. Stenting was elective in 171 patients (64%), and the majority of patients (91%) were treated with aspirin plus ticlopidine.

RESULTS

A successful angiographic result was achieved in 258 patients (96%). Minimum lumen diameter was increased from 0.2 +/- 0.3 to 2.7 +/- 0.7 mm (p < 0.001), and stenosis decreased from 94 +/- 8% to 13 +/- 11% (p < 0.001). Mortality was 15.3% (3.2%, 24.4% and 67.7% in patients in Killip class I, II-III and IV, respectively). Nonfatal reinfarction and recurrent ischemia rates were 2.6% and 9%, respectively. Stent thrombosis occurred in 8 patients (3.0%), and new target vessel revascularization was needed in 12 (4.5%).

CONCLUSIONS

Stent placement in acute myocardial infarction is associated with high angiographic success rate, as well as a good in-hospital outcome. Mortality is localized, especially in patients with cardiac failure at the beginning of the procedure.

Coronary angioplasty with or without stent implantation for acute myocardial infarction. Stent Primary Angioplasty in Myocardial Infarction Study Group

BACKGROUND

Coronary-stent implantation is frequently performed for treatment of acute myocardial infarction. However, few studies have compared stent implantation with primary angioplasty alone.

METHODS

We designed a multicenter study to compare primary angioplasty with angioplasty accompanied by implantation of a heparin-coated Palmaz-Schatz stent. Patients with acute myocardial infarction underwent emergency catheterization and angioplasty. Those with vessels suitable for stenting were randomly assigned to undergo angioplasty with stenting (452 patients) or angioplasty alone (448 patients).

RESULTS

The mean (+/-SD) minimal luminal diameter was larger after stenting than after angioplasty alone (2.56+/-0.44 mm vs. 2.12+/-0.45 mm, P<0.001), although fewer patients assigned to stenting had grade 3 blood flow (according to the classification of the Thrombolysis in Myocardial Infarction trial) (89.4 percent, vs. 92.7 percent in the angioplasty group; P=0.10). After six months, fewer patients in the stent group than in the angioplasty group had angina (11.3 percent vs. 16.9 percent, P=0.02) or needed target-vessel revascularization because of ischemia (7.7 percent vs. 17.0 percent, P<0.001). In addition, the combined primary end point of death, reinfarction, disabling stroke, or target-vessel revascularization because of ischemia occurred in fewer patients in the stent group than in the angioplasty group (12.6 percent vs. 20.1 percent, P<0.01). The decrease in the combined end point was due entirely to the decreased need for target-vessel revascularization. The six-month mortality rates were 4.2 percent in the stent group and 2.7 percent in the angioplasty group (P=0.27). Angiographic follow-up at 6.5 months demonstrated a lower incidence of restenosis in the stent group than in the angioplasty group (20.3 percent vs. 33.5 percent, P<0.001).

CONCLUSIONS

In patients with acute myocardial infarction, routine implantation of a stent has clinical benefits beyond those of primary coronary angioplasty alone.

Long-term benefit of primary angioplasty as compared with thrombolytic therapy for acute myocardial infarction

BACKGROUND

As compared with thrombolytic therapy, primary coronary angioplasty results in a higher rate of patency of the infarct-related coronary artery, lower rates of stroke and reinfarction, and higher in-hospital or 30-day survival rates. However, the comparative long-term efficacy of these two approaches has not been carefully studied.

METHODS

We randomly assigned a total of 395 patients with acute myocardial infarction to treatment with angioplasty or intravenous streptokinase. Clinical information was collected for a mean (+/-SD) of 5+/-2 years, and medical charges associated with the two treatments were compared.

RESULTS

A total of 194 patients were assigned to undergo primary angioplasty, and 201 to receive streptokinase. Mortality was 13 percent in the angioplasty group, as compared with 24 percent in the streptokinase group (relative risk, 0.54; 95 percent confidence interval, 0.36 to 0.87). Nonfatal reinfarction occurred in 6 percent and 22 percent of the two groups, respectively (relative risk, 0.27; 95 percent confidence interval, 0.15 to 0.52). The combined incidence of death and nonfatal reinfarction was also lower among patients assigned to angioplasty than among those assigned to streptokinase, with a relative risk of 0.13 (95 percent confidence interval, 0.05 to 0.37) for early events (within the first 30 days) and a relative risk of 0.62 (95 percent confidence interval, 0.43 to 0.91) for late events (after 30 days). The rates of readmission for heart failure and ischemia were also lower among patients in the angioplasty group than among patients in the streptokinase group. Total medical charges per patient were lower in the angioplasty group (16,090 dollars) than in the streptokinase group (16,813 dollars, P=0.05).

CONCLUSIONS

During five years of follow-up, primary coronary angioplasty for acute myocardial infarction was associated with lower rates of early and late death and nonfatal reinfarction, fewer hospital readmissions for ischemia or heart failure, and lower total medical charges than treatment with intravenous streptokinase.

Coronary stent deployment without predilation in acute myocardial infarction: a feasible, safe, and effective technique

Direct percutaneous transcatheter revascularization (PTCR) is becoming an acceptable therapy for acute myocardial infarction (AMI). Stenting in the setting of AMI, once considered contraindicated, is emerging as a suitable option in this situation. Coronary stenting without predilation (SWOP) may potentially shorten the procedure and radiation time, reduce costs, and decrease procedural complications such as coronary dissection and distal embolization. It is expected to cause less vascular injury, with a reduction in the rate of in-stent restenosis. In this preliminary study the authors evaluated the feasibility of the SWOP procedure in 22 selected patients with AMI. Indications for catheter-based myocardial reperfusion were the following: extensive anterior wall MI (68%), inferior wall and right ventricular MI (23%), and inferior wall MI with contraindication for thrombolytic therapy (9%). Patients with cardiogenic shock or with contraindications for aspirin or ticlopidine were excluded. SWOP was successful in 21 attempts (95%), and final procedural success was achieved in all. Proximal or distal dissections were seen in three cases and were treated by additional three stents. Thrombolysis in myocardial infarction (TIMI) flow 3 was restored in all patients. There were no distal embolizations, side branch occlusions, coronary perforations, procedure-related emergency bypass operations, or deaths. It is concluded that in selected patients with AMI, coronary artery stenting without predilation is feasible and safe and does not introduce additional risk to the patients.

Primary stent implantation is superior to balloon angioplasty in acute myocardial infarction: final results of the primary angioplasty versus stent implantation in acute myocardial infarction (PASTA) trial. PASTA Trial Investigators

Several studies have shown that stent implantations in acute myocardial infarction (AMI) result in better short- and long-term outcomes than primary balloon angioplasty. These results, however, have not been ascertained in randomized trials. We randomized 136 patients out of 208 patients with AMI within 12 hr from onset into two groups: 69 patients with primary balloon angioplasty (POBA group) and 67 patients with primary stent implantation (STENT group). We compared the incidences of major cardiac events (repeat MI, target lesion revascularization, and cardiac death) and angiographic parameters during hospitalization and follow-up periods up to 12 months in these two groups. There was no significant difference in the reperfusion success rates. The incidences of major cardiac events were lower in the STENT group than in the POBA group during hospitalization, the first 6 months and 12 months (6% vs. 19%, P = 0.023; 21% vs. 46%, P < 0.0001; 22% vs. 49%, P = 0.0011). Minimum lumen diameters were significantly bigger in the STENT group than the POBA group at predischarge angiogram and 6-month follow-up (2.85 +/- 0.62 vs. 2.08 +/- 0.82 mm, P < 0.0001; 2.24 +/- 0.64 vs. 1.72 +/- 0.76, P = 0.002). Restenosis rates at 6-month follow-up were significantly lower in the STENT group than in the POBA group (17% vs. 37.5%, P = 0.02). In selected patients with AMI, primary stent implantation results in a lower incidence of major cardiac events during the first 12 months, postprocedure, and less frequent 6-month restenosis than primary balloon angioplasty.

Primary coronary infarct artery stenting in acute myocardial infarction

Completed and ongoing randomized trials have provided results that favor primary infarct-related artery (IRA) stenting as opposed to primary percutaneous transluminal coronary angioplasty, but the applicability of the trial results to all patients with acute myocardial infarction (AMI) has not yet been investigated. This study sought to determine the applicability of an unconditional IRA stenting strategy in nonselected patients with AMI. After successful mechanical recanalization of the IRA, all patients with AMI and a reference diameter > or =2.5 mm were considered eligible for primary IRA stenting without any restriction regarding age or clinical status on presentation. The primary end point of the study was a composite end point defined as death, reinfarction, or repeat target lesion revascularization. Primary IRA stenting was successfully performed in 161 of 190 consecutive patients with AMI (85%), and of 162 (99%) considered suitable for stenting. Patients with nonstented IRA had a reference IRA diameter smaller than patients with a stent (2.71+/-0.48 vs 3.20+/-0.41 mm, p <0.001). Overall, the 6-month mortality was 5%. Mortality was 2% for patients without, and 32% for patients with cardiogenic shock. The incidences of reinfarction and of repeat target lesion revascularization were 1% and 12%, respectively. The 6-month angiographic follow-up showed an IRA patency rate of 94% and a restenosis rate of 26%. The results of this study strengthen the hypothesis that unconditional primary IRA stenting is highly feasible, and may actually improve the outcome of patients with AMI.

Clinical trials in acute myocardial infarction

Long-term follow-up of placebo-controlled thrombolysis trials has proven that the survival benefit from thrombolysis in acute myocardial infarction (AMI) is maintained for up to 10 years. Ongoing research is being conducted with the aim to further improve early restoration of blood flow in the infarct vessel and, thus, reperfusion of the infarcted myocardium in patients with AMI, with the ultimate goal to improve survival. In two recent mega-trials, two new single-bolus fibrinolytics (lanoteplase and TNK-tissue plasminogen activator) were shown to be equivalent to front-loaded alteplase in reducing infarct mortality. The ease of application of these agents might help reduce the time from symptom onset to start of therapy. More potent thrombin inhibitors such as hirudin and hirulog seem to speed up thrombolysis with streptokinase and reduce the rate of reinfarctions. Very promising results are derived from angiographic trials combining reduced doses of thrombolytics with glycoprotein IIb/IIIa inhibitors. Advances in mechanical revascularization can be achieved with the use of stents and better conjunctive therapies. All of these developments are expected to further improve clinical outcome of patients with AMI in the near future.

Current role of stenting in acute myocardial infarction

Primary infarct artery stenting has the potential to advance treatment of acute myocardial infarction. The postulated mechanisms of the benefit of stenting in acute myocardial infarction are the achievement of an acute optimal angiographic result and correction of any residual dissection to decrease the incidence of early and late restenosis and reocclusion and of the correlated events such as fatal and nonfatal reinfarction and repeat target vessel revascularization for recurrent ischemia. The results of 5 completed randomized trials comparing primary stenting with primary percutaneous transluminal coronary angioplasty show a lower incidence of the composite end point of death, myocardial infarction, and repeat target vessel revascularization in the stent groups as compared with the angioplasty groups and support the more extensive use of stents in patients with acute myocardial infarction. The efforts of the next years will be focused on further refinement of stent design and composition and the evaluation of pharmacological agents effective in restoring myocardial reperfusion to the fullest extent.

Results of coronary stenting after delayed angioplasty of the culprit vessel in patients with recent myocardial infarction

Little information is available concerning the effect of late coronary stenting in patients with recent myocardial infarction, especially long-term results. We retrospectively reviewed our results of 57 stent placements in 52 consecutive patients who received stents at an infarct-related lesion 24 hr to 30 days after an acute myocardial infarctions (median, 14 days). The average age was 67 years; 90% were male. Two patients who suffered from acute stent thrombosis received revascularization again and two early deaths were due to refractory cardiogenic shock before discharge. Mean patient clinical follow-up was 18.3 +/- 6.5 months. There were 1 subacute stent thrombosis, 1 cardiogenic death, and 10 patients (20.8%) in total suffering from angina class II to IV. Angiographic follow-up was performed in 36 patients (80%) at a mean of 7.5 +/- 3.1 months. Of these 36 patients, only 1 (3% of the total population undergoing follow-up angiography) had reocclusion at follow-up, but restenosis existed in 18 patients (50%). We conclude that there is still relatively high incidence of angiographic recurrence that is often silent in long-term follow-up, though the long-term result of late stenting in recent MI is low incidence of reocclusion.

Do new devices add to the results of PTCA in acute myocardial infarction?

Several randomized trials have established that timely mechanical reperfusion with the use of balloon angioplasty is superior to thrombolytic therapy in patients with acute myocardial infarction. Furthermore, recent data from prospective randomized trials suggest that primary stent implantation may further improve the results of balloon angioplasty by reducing the need for repeat interventions at follow-up. The role of IIb-IIIa platelet receptor antagonists as adjunctive therapy to catheter-based coronary interventions in acute myocardial infarction is promising, but the incremental benefit that these agents add to stent implantation awaits the results of dedicated randomized trials. Mechanical thrombolysis or thrombectomy devices may have a role in a minority of patients with large thrombus burden.

Reperfusion therapy in cardiogenic shock complicating acute myocardial infarction

The most frequent cause of cardiogenic shock complicating acute myocardial infarction is extensive myocardial damage involving a relevant amount of myocardium. Treatment is aimed at support for the circulation with the use of drugs and mechanical devices and at restoration of perfusion to the ischemic myocardium as soon as possible. Therefore, emergency coronary angiography is indicated in all patients. Coronary angioplasty is the first option in patients with suitable anatomy because it is the fastest available technique able to recanalize the infarct-related vessel. Stenting of the infarct artery must be considered because stent implantation has been shown to improve results in comparison with the balloon alone. Complete revascularization is likely to offer a better outcome in patients with multivessel disease. Coronary surgery is indicated as first-line intervention in patients who have a coronary anatomy not suitable for angioplasty; it may also serve to complete revascularization in patients with multivessel disease initially treated with emergency coronary angioplasty. In a hospital without facilities for emergency coronary interventions, mechanical circulatory support with an intra-aortic balloon pump should be instituted and thrombolysis started; then patients should be transferred immediately to a tertiary center to undergo coronary angiography and revascularization procedures, if needed. In patients not benefiting from this aggressive revascularization strategy who develop irreversible extensive myocardial damage, heart transplantation must be considered.

Primary stenting and glycoprotein IIb/IIIa inhibitors in acute myocardial infarction

Early patency of the infarct-related vessel improves in-hospital and long-term survival. Mechanical reopening is as effective as or superior to pharmacological therapy in the treatment of acute myocardial infarction. However, in patients treated with primary percutaneous transluminal coronary angioplasty, recurrent ischemia occurs in 10% to 15% before hospital discharge, and angiographic restenosis occurs in 30% to 50% of infarct-related vessel within 6 months. Primary stenting in acute myocardial infarction has been found to be safe and feasible and reduces early and late events. In particular, restenosis rate has been found to be lowered by stent implantation. Use of glycoprotein IIb/IIIa receptor inhibitors alone has resulted in infarct-related vessel patency rates approximately the same as with the use of thrombolytic therapy. Furthermore, glycoprotein IIb/IIIa receptor blockers reduce the occurrence of acute complications during percutaneous transluminal coronary angioplasty. Preliminary results of some ongoing trials showed that the combined therapeutic approach (ie, primary stenting plus glycoprotein IIb/IIIa inhibitors) in patients with acute myocardial infarction reduces both early and late complications of percutaneous transluminal coronary angioplasty. This finding supports the concept that optimal mechanical resolution of the plaque and the inhibition of platelet aggregation are the key of the treatment of the infarct-related vessel.

Coronary angioplasty or intravenous thrombolysis: the dilemma of optimal reperfusion in acute myocardial infarction: A critical review of the literature

Thrombolytic therapy in acute myocardial infarction reduces infarct size and prolongs survival. Coronary reperfusion can also be achieved by direct (primary) percutaneous transluminal coronary angioplasty (PTCA). Whereas thrombolysis has the benefits of simplicity and ease of administration, PTCA achieves high reperfusion rates at a relatively low risk of bleeding and is less frequently contraindicated. These two strategies were evaluated in randomized trials as well as in a number of large registries. In most of the randomized trials, PTCA was found to yield better results than thrombolysis, although the largest randomized trial found only a modest and transient benefit. The registries, on the other hand, found no difference between the two treatment strategies. We analyze the available data and discuss the possible causes for the discrepant results in different studies. PTCA seems to be a better strategy to open occluded coronary arteries, but its clinical benefit is critically dependent on operator experience and on the time to treatment. It is the treatment of choice if the culprit lesion can be crossed within 1 hour of presentation. Home thrombolysis offers the chance of very early reperfusion and may be the most cost-effective way of improving the overall results of reperfusion therapy in the community. Coronary stenting and more effective platelet inhibition may improve the results of medical and interventional reperfusion, and further comparisons of these two strategies will be required.

Optimal management of acute myocardial infarction at the dawn of the next millennium

At the dawn of the next millennium, the optimal management of acute myocardial infarction will have been defined by multiple clinical trials of acute reperfusion strategies, in conjunction with adjunctive pharmacotherapy. Reperfusion therapy with thrombolytic agents or primary angioplasty is the standard of care for many patients examined with ST-segment elevation or left bundle branch block within approximately 12 hours of symptoms. The superiority of fibrin-specific agents over streptokinase has been established, as have the advantages of primary angioplasty in selected institutions with the requisite expertise and logistical capabilities. The key to successful reperfusion lies more in the efficiency of delivery than in the choice of modality. Reocclusion remains the "Achilles' heel" of reperfusion therapy, as does the presence of reperfusion injury microvascular dysfunction and the "no-reflow" phenomenon. These entities are major targets for further investigation in the next 5 years. The wealth of adjunctive pharmacologic agents currently available presents a challenge to the optimal treatment of myocardial infarction. A major objective is to define the magnitude of the incremental benefits and risks of using the available and new drugs, both alone and in combination. Moreover, community-wide studies indicate a marked underutilization of therapies that are available and are of proven effectiveness. The key to optimal management, as we enter the new millennium, lies in the search for new therapies in concert with the most effective use of those agents already at our disposal.

Coronary stenting during rescue angioplasty after failed thrombolysis

Compared with primary angioplasty [percutaneous transluminal coronary angioplasty (PTCA)], rescue PTCA is associated with lower angiographic success and higher reocclusion rates, especially after thrombolysis with tissue-type plasminogen activator (tPA). Although stent placement during primary PTCA has been demonstrated to be safe and even to improve the angiographic results achieved by balloon-alone PTCA, there are few data on stent placement during rescue PTCA after failed thrombolysis. This study sought to assess the feasibility and safety of stent implantation during rescue angioplasty in myocardial infarction after failed thrombolysis. The study population consisted of 20 patients with acute myocardial infarction referred for rescue PTCA after failed thrombolysis consecutively treated with coronary stenting. The thrombolytic agent was tPA in 15 patients (75%), streptokinase in 1 (5%), and anisoylated streptokinase plasminogen activator complex (APSAC) in 1 (5%); 3 patients (15%) were included in the INTIME II study (tPA vs. lanoteplase). After stenting, aspirin 200 mg daily plus ticlopidine 250 mg b.i.d. were administered. Thirty stents (1.5+/-1.0 per patient) were implanted. Angiographic success was achieved in 19 patients (95%). Two patients (10%) died, both because of severe bleeding complications. One patient (5%) suffered a reinfarction, but no patients suffered postinfarction angina or needed new target vessel revascularization. Eighteen patients (90%) were discharged alive and free of events. All these patients remained asymptomatic and free of target vessel revascularization at 6-month follow-up. Stent placement during rescue PTCA after failed thrombolysis is feasible and safe and is associated with a good angiographic result and clinical outcome. Bleeding complications seem to be, however, the main limitation of this reperfusion strategy.

Coronary stent implantation in acute myocardial infarction

BACKGROUND

The purpose of this study was to provide an overview on stenting in acute myocardial infarction (MI).

METHODS AND RESULTS

A search of MEDLINE and the scientific sessions abstracts in peer review journals through May 1998 was carried out to identify any publications on stenting in MI. The settings were retrospective and prospective case series on stenting in MI, nonrandomized and randomized trials comparing primary stenting and primary percutaneous transluminal coronary angioplasty (PTCA) in MI, and stenting in cardiogenic shock complicating MI. Reported outcomes included procedural success, reocclusion, restenosis, and target vessel revascularization rates; incidence of death, MI, recurrent ischemia, major bleeding, and vascular complications; and incidence of cerebrovascular accidents. Procedural success rates were better for stenting than primary PTCA, and postprocedural minimum luminal diameters were larger. This resulted in lower reocclusion and restenosis rates and a lesser need for target vessel revascularization with primary stenting. The incidence of death, MI, and recurrent ischemia was also reduced with primary stenting. Major bleeding and vascular complications were confined to patients receiving anticoagulation as opposed to antiplatelet agents after stenting. Finally, a strategy of bailout stenting for failed PTCA in MI appears to be inferior to a primary stenting strategy.

CONCLUSIONS

Stenting in MI is an effective and safe reperfusion strategy with many advantages compared with primary PTCA.

Efficacy of transradial primary stenting in patients with acute myocardial infarction

We conducted a prospective observational study to assess the effectiveness of "transradial primary stenting" in 33 patients with acute myocardial infarction, along with acute risk stratification and accelerated patient care. With use of adequate inclusion and exclusion criteria, the radial artery can be used as an access site for catheterization, and transradial primary stenting can be performed rapidly and successfully by trained coronary interventionalists.

Angiographic assessment of myocardial reperfusion in patients treated with primary angioplasty for acute myocardial infarction: myocardial blush grade. Zwolle Myocardial Infarction Study Group

BACKGROUND

The primary objective of reperfusion therapies for acute myocardial infarction is not only restoration of blood flow in the epicardial coronary artery but also complete and sustained reperfusion of the infarcted part of the myocardium.

METHODS AND RESULTS

We studied 777 patients who underwent primary coronary angioplasty during a 6-year period and investigated the value of angiographic evidence of myocardial reperfusion (myocardial blush grade) in relation to the extent of ST-segment elevation resolution, enzymatic infarct size, left ventricular function, and long-term mortality. The myocardial blush immediately after the angioplasty procedure was graded by two experienced investigators, who were otherwise blinded to all clinical data: 0, no myocardial blush; 1, minimal myocardial blush; 2, moderate myocardial blush; and 3, normal myocardial blush. The myocardial blush was related to the extent of the early ST-segment elevation resolution on the 12-lead ECG. Patients with blush grades 3, 2, and 0/1 had enzymatic infarct sizes of 757, 1143, and 1623 (P<0.0001), respectively, and ejection fractions of 50%, 46%, and 39%, respectively (P<0.0001). After a mean+/-SD follow-up of 1.9+/-1.7 years, mortality rates of patients with myocardial blush grades 3, 2, and 0/1 were 3%, 6%, and 23% (P<0.0001), respectively. Multivariate analysis showed that the myocardial blush grade was a predictor of long-term mortality, independent of Killip class, Thrombolysis In Myocardial Infarction grade flow, left ventricular ejection fraction (LVEF), and other clinical variables.

CONCLUSIONS

In patients after reperfusion therapy, the myocardial blush grade as seen on the coronary angiogram can be used to describe the effectiveness of myocardial reperfusion and is an independent predictor of long-term mortality.