Primary angioplasty for acute myocardial infarction

The comparative stability of eight different triplexes constituted with 16-mer pyrimidine-modified oligodeoxynucleotides (wild-type ODN, PS-ODN, alpha-ODN, or alpha-PS-ODN) or oligoribonucleotides (wild-type ORN, alpha-ORN, 4'-thio-ORN, or 2'-O-MeORN) and a DNA hairpin, termed H36, was studied in five different buffers by UV melting curve analysis. The composition of buffers varied in pH (5.5 and 6.5), in salt concentration (100 mM and 1 M Na+), and in the presence or absence of divalent cation (0 or 3 mM Mg2+) or spermine (0 or 1 mM). At pH 5.5, the eight triplexes are formed with Tm values ranging from 24.7 degrees C to 50.9 degrees C (delta G298K between -8.1 and -16.8 kcal/mol). At pH 6.5, the triplexes are less stable, and thus 4'-thio-ORN and PS-ODN showed broad transitions that did not allow us to conclude triplex formation. An increase of salt concentration or the presence of spermine stabilizes the triplexes, whereas Mg2+ has a destabilizing effect (excepted for alpha-ORN). In general ORN:H36 and 2'-O-MeORN:H36 triplexes were the most stable. Finally, introduction of alpha-anomeric nucleosides led to an alpha-ORN analog that showed low binding with H36 and to alpha-ODN and alpha-PS-ODN analogs. Triplexes formed with alpha-ODN were slightly less stable than those formed with unmodified ODN. Surprisingly, introduction of phosphorothioate in an alpha analog led only to a low destabilization.     

Abciximab in primary coronary angioplasty for acute myocardial infarction improves short- and medium-term outcomes

OBJECTIVES: The purpose of this study was to compare the outcome of primary percutaneous transluminal coronary angioplasty for acute myocardial infarction (MI) when performed with or without the platelet glycoprotein IIb/IIIa antibody, abciximab. BACKGROUND: Abciximab improves the outcome of angioplasty but the effect of abciximab in primary angioplasty has not been investigated. METHODS: Data were collected from a computerized database. Follow-up was by telephone or review of outpatient or hospital readmission records. RESULTS: A total of 182 consecutive patients were included; 103 received abciximab and 79 did not. The procedural success rate was 95% in the two groups. At 30-day follow-up, the composite event rate of unstable angina, reinfarction, target vessel revascularization and death from all causes was 13.5% in the group of patients who did not receive abciximab, 4% (p < 0.05) in the abciximab group and 2.4% (p < 0.05) in the subgroup of patients (n = 87) who completed the 12-h abciximab infusion. At the end of follow-up (mean 7+/-4 months), the composite event rate was 32.4%, 17% (p < 0.05) and 13.1% (p < 0.01) in these three categories respectively. Abciximab bolus followed by a 12-h infusion was an independent predictor of event-free survival, in a Cox proportional hazards model (relative risk 0.49; 95% confidence interval 0.24 to 0.99; p < 0.05). CONCLUSIONS: Abciximab given at the time of primary angioplasty may improve the short- and medium-term outcome of patients with acute MI, especially when a 12-h infusion is completed.     

Intravascular ultrasound findings after successful primary angioplasty for acute myocardial infarction: predictors of abrupt occlusion

OBJECTIVES: This study sought to evaluate the intravascular structure as depicted by intravascular ultrasound after successful primary angioplasty (i.e., without thrombolytic therapy) for acute myocardial infarction and to investigate the related predictors of acute coronary occlusion. BACKGROUND: The usefulness of primary angioplasty for acute myocardial infarction is still limited by early reocclusion. There are few data regarding the intravascular ultrasound findings after primary angioplasty. METHODS: Intravascular ultrasound was performed in 27 patients after successful primary angioplasty. Repeat coronary angiography was performed 15 min later, on the following day and 1 month after angioplasty. RESULTS: Abrupt occlusion occurred in 8 of 27 patients. Angiographic variables in patients with versus those without abrupt occlusion were not significantly different. Intravascular ultrasound disclosed a significantly smaller lumen area ([mean +/- SD] 2.49 +/- 0.72 vs. 5.06 +/- 1.52 mm2, p < 0.001) and a significantly greater percent plaque area (80.5 +/- 9.1% vs. 63.7 +/- 7.8%, p < 0.001) in patients with abrupt occlusion. There was no significant difference in external elastic membrane cross-sectional area. We classified the ultrasound appearance of the intravascular structure as smooth, irregular or filled. Abrupt occlusion occurred in none of 6 patients with a smooth intravascular structure, 24% of 17 patients with an irregular structure and in all 4 with a filled structure (p < 0.05). In the latter group, the lumen was filled with bright speckled or low echogenic material, although angiography revealed excellent coronary dilation in all these arteries. CONCLUSIONS: Intravascular ultrasound revealed a narrow lumen in coronary arteries showing abrupt occlusion after successful primary angioplasty, even though angiography disclosed successful dilation. Arteries with a lumen filled with bright speckled or low echogenic material frequently develop abrupt occlusion.     

Fibrinolysis or angioplasty in acute myocardial infarction?

Early reperfusion during myocardial infarction limits myocardial injury and reduces mortality. Fibrinolysis (with streptokinase, or tissue or recombinant plasminogen activators) is today an established method for the treatment of myocardial infarction patients manifesting ST-segment elevation or left bundle branch block at ECG (electrocardiography), effective reperfusion being obtained in fifty per cent of cases. Extensive developments are under way, both of fibrinolytic substances and of various adjuvant treatments. A satisfactory alternative treatment to fibrinolysis is percutaneous transluminal coronary angioplasty (PTCA), a method which can be used when fibrinolysis is contraindicated or during cardiogenic shock, or when there is no sign of reperfusion in response to fibrinolytic treatment. Provided the facilities and competence are available, PTCA can even be used as primary treatment instead of fibrinolysis.     

Pericardial effusion after primary percutaneous transluminal coronary angioplasty in first Q-wave acute myocardial infarction

To evaluate the incidence and clinical significance of infarction-associated pericardial effusion in patients with successful primary percutaneous transluminal coronary angioplasty, we studied 214 consecutive patients with a first Q-wave acute myocardial infarction. Based on 9 clinical variables, multivariate analysis was performed to determine the important variables related to the occurrence of pericardial effusion. Pericardial effusion was detected by echocardiography in 45 patients (21%); pericardial rub (p <0.001), number of advanced asynergic segments (p <0.001), ventricular aneurysmal motion (p = 0.03), and pulmonary capillary wedge pressure (p = 0.04) were found to be the important variables related to pericardial effusion. Among 45 patients with pericardial effusion, 29 patients with no pericardial rub had significantly higher pulmonary capillary wedge pressure than those with pericardial rub, whereas 16 patients with pericardial rub had a higher incidence of angiographic no reflow and ventricular aneurysmal motion than those without pericardial rub. Patients with pericardial effusion and a pericardial rub had a higher mortality rate than those without pericardial effusion (19% vs 3%; p = 0.02). Thus, pericardial effusion is still a relatively common clinical finding after primary percutaneous transluminal coronary angioplasty, and those with pericardial effusion and a pericardial rub were associated with more severe transmural myocardial damage and higher in-hospital mortality.     

Heterogeneity of prognosis in patient subsets treated by primary coronary angioplasty during acute myocardial infarction

Among 377 patients consecutively treated with primary coronary angioplasty for acute myocardial infarction, in-hospital mortality was higher in patients ineligible than in patients eligible for thrombolysis (14.4% vs 7.8%, p <0.05). It remained dismal (75.9%) in patients with cardiogenic shock, but was similar in lytic-eligible patients and in those who were ineligible because of an increased bleeding risk (7.8% vs 7.2%, p = NS), and was zero in patients with nondiagnostic electrocardiograms.     

Comparison of primary coronary stenting to primary balloon angioplasty with stent bailout for the treatment of patients with acute myocardial infarction

This study compares the immediate and long-term outcomes of a primary coronary stenting strategy with primary balloon angioplasty with stent bailout in the treatment of patients with acute myocardial infarction (AMI). One hundred forty-seven consecutive patients who underwent primary balloon angioplasty with stent bailout (n = 94) or primary stenting (n = 53) for AMI were clinically followed for 8.1 +/- 5.7 and 8.5 +/- 4.5 months, respectively. Immediate results, as well as in-hospital and long-term ischemic events (death, reinfarction, and repeat revascularization) were compared between both groups. Angiographic success was 91.5% in the balloon angioplasty group and 94% in the stent group. In-hospital and late follow-up combined ischemic events were 22 of 94 (23%) versus 0 of 53 (0%); p < 0.001 and 33 of 78 (42%) versus 13 of 53 (25%), p = 0.04 for the balloon angioplasty and stent groups, respectively. At 6 months, the cumulative probability of repeat target lesion revascularization was higher in the balloon angioplasty group (47% vs 18%, p = 0.0006) as was the probability of late target revascularization (36% vs 18%, p = 0.046); the cumulative event-free survival after 6 months was significantly lower in the balloon angioplasty group (44% vs 80%, p = 0.0001). This study demonstrates that a primary stent placement strategy in patients with AMI is safe, feasible, and superior to primary balloon angioplasty with stent bailout. Primary stenting results in a larger postprocedural minimal luminal diameter, a lower early and late recurrent ischemic event rate, and a lower incidence of target lesion revascularization at follow-up.     

Myocardial contrast echocardiography versus dobutamine echocardiography for predicting functional recovery after acute myocardial infarction treated with primary coronary angioplasty

OBJECTIVES: We sought to compare myocardial contrast echocardiography with low dose dobutamine echocardiography for predicting 1-month recovery of ventricular function in acute myocardial infarction treated with primary coronary angioplasty. BACKGROUND: The relation between myocardial perfusion and contractile reserve in patients with acute myocardial infarction, in whom anterograde flow is fully restored without significant residual stenosis, is still unclear. METHODS: Thirty patients with acute myocardial infarction treated successfully with primary coronary angioplasty underwent intracoronary contrast echocardiography before and after angioplasty and dobutamine echocardiography 3 days after the index infarction. One month later, two-dimensional echocardiography and coronary angiography were repeated in all patients and contrast echocardiography in 18 patients. RESULTS: After coronary recanalization, 26 patients showed myocardial reperfusion within the risk area, although 4 did not. At 1-month follow-up, all patients had a patient infarct-related artery without significant restenosis. Both left ventricular ejection fraction and wall motion score index within the risk area significantly improved in the patients with reperfusion ([mean +/- SD] 38 +/- 8% vs. 48 +/- 12%, p < 0.005; and 2.35 +/- 0.5 vs. 2 +/- 0.6, p < 0.001, respectively), but not in those with no reflow. Of the 72 nonperfused segments before angioplasty, 27 showed functional improvement at follow-up. Myocardial contrast echocardiography had a sensitivity and a negative predictive value similar to dobutamine echocardiography in predicting late functional recovery (96% vs. 89% and 89% vs. 93%, respectively), but a lower specificity (18% vs. 91%, p < 0.001), positive predictive value (41% vs. 86%, p < 0.001) and overall accuracy (47% vs. 90%, p < 0.001). CONCLUSIONS: Microvascular integrity is a prerequisite for myocardial viability after acute myocardial infarction. However, contrast enhancement shortly after recanalization does not necessarily imply a late functional improvement. Thus, contractile reserve elicited by low dose dobutamine is a more accurate predictor of regional functional recovery after reperfused acute myocardial infarction than microvascular integrity.     

A comparison of thrombolytic therapy with primary coronary angioplasty for acute myocardial infarction. Myocardial Infarction Triage and Intervention Investigators

BACKGROUND: Several relatively small randomized trials have shown that primary angioplasty results in a better short-term outcome than thrombolytic therapy in patients with acute myocardial infarction. These results, however, have not been duplicated other than in investigational trials. METHODS: We compared mortality during hospitalization and long-term mortality, as well as the use of resources, among 1050 patients in a primary-angioplasty group and 2095 patients in a thrombolytic-therapy group. Patients were selected from the Myocardial Infarction Triage and Intervention Project Registry cohort of 12,331 consecutive patients admitted with acute myocardial infarction to 19 Seattle hospitals between 1988 and 1994. Because of the potential for selection bias, several subgroup analyses were performed that included patients eligible for thrombolysis, high-risk patients, and patients in the primary-angioplasty group who were treated at hospitals with high volumes of angioplasty. RESULTS: There was no significant difference in mortality during hospitalization or long-term follow-up between patients in the thrombolytic-therapy group and those in the primary-angioplasty group (mortality during hospitalization, 5.6 percent and 5.5 percent, respectively; P=0.93; adjusted hazard ratio for the risk of death within three years after primary angioplasty, 0.95; 95 percent confidence interval, 0.8 to 1.2). There was also no significant difference in mortality between high-risk subgroups of patients in the two treatment groups. The rates of procedures and costs were lower among patients in the thrombolytic-therapy group both at the time of hospital discharge and after three years of follow-up (30 percent fewer coronary angiograms, 15 percent fewer coronary angioplasties, and 13 percent lower costs after three years of follow-up). CONCLUSIONS: In a community setting, we observed no benefit in terms of either mortality or the use of resources with a strategy of primary angioplasty rather than thrombolytic therapy in a large cohort of patients with acute myocardial infarction.     

Importance of infarct-related artery patency for recovery of left ventricular function and late survival after primary angioplasty for acute myocardial infarction

OBJECTIVES: The purpose of this study was to evaluate the importance of late infarct-related artery patency for recovery of left ventricular function and late survival after primary angio-plasty for acute myocardial infarction. BACKGROUND: Infarct-related artery patency is thought to improve late survival by its effect on preservation of left ventricular function. Patency may also enhance late survival by preventing left ventricular dilation and reducing arrhythmias, independent of myocardial salvage. However, most studies have not shown patency to be an independent predictor of survival when late left ventricular function is taken into account. METHODS: We followed up 576 hospital survivors of acute myocardial infarction treated with primary angioplasty for 5.3 years. Ejection fraction and infarct-related artery patency were determined at follow-up catheterization at 6 months. Predictors of late cardiac survival were determined using Cox regression models. RESULTS: Patients with patent arteries had more improvement and a better late ejection fraction than patients with occluded arteries (56.3% vs. 47.9%, p = 0.001). In patients with acute ejection fraction < 45%, late survival was better in those with patent versus occluded arteries (89% vs. 44%, p = 0.003), but patency was not a significant predictor after improvement in ejection fraction was taken into account. In patients with a large anterior infarction, patency was a significant independent predictor of late survival. CONCLUSIONS: Infarct-related artery patency is important for recovery of left ventricular function, and in patients with acute ejection fraction < 45%, patency is important for late survival. Our data are consistent with the hypothesis that the survival benefit is due primarily to the effect of patency on recovery of left ventricular function. In patients with a large anterior infarction, patency appears to provide an additional late survival benefit independent of myocardial salvage. These observations support the need for additional clinical trials of late reperfusion in patients with a large anterior infarction.     

Randomized trial of direct coronary angioplasty versus intravenous streptokinase in acute myocardial infarction

OBJECTIVES: The objective of this study was to obtain preliminary data on the relative clinical utility of direct coronary angioplasty compared with that of intravenous thrombolytic therapy for patients with acute myocardial infarction. BACKGROUND: The relative merits of intravenous thrombolytic therapy and direct coronary angioplasty as treatment for acute myocardial infarction are incompletely understood, and randomized trials of these treatments have been extremely limited. METHODS: One hundred patients with ST segment elevation presenting to a single high volume interventional center within 6 h of the onset of chest pain were randomized to receive either streptokinase (1.2 million U intravenously over 1 h) or immediate catheterization and direct coronary angioplasty. Patients were excluded for age > or = 75 years, prior bypass surgery, Q wave infarction in the region of ischemia or excessive risk of bleeding. All patients were then treated with aspirin (325 mg orally/day) and heparin (1,000 U intravenously/h) for 48 h until catheterization was performed to determine the primary study end point, namely, infarct-related artery patency at 48 h. Secondary end points were in-hospital death, left ventricular ejection fraction at 48 h and time to treatment. RESULTS: There was no difference in the baseline characteristics of the two treatment groups. Overall patient age was 56 +/- 10 years, 83% of patients were male, 11% had prior infarction, 40% had anterior infarction and 97% were in Killip class I or II. Although time to treatment was delayed in the angioplasty group (238 +/- 112 vs. 179 +/- 98 min, p = 0.005), there was no difference in 48-h infarct-related artery patency or left ventricular ejection fraction (patency 74% vs. 80%; ejection fraction 59 +/- 13% vs. 57 +/- 13%; angioplasty vs. streptokinase, p = NS for both). There were no major bleeding events, and the mortality rate with angioplasty (6%) and streptokinase (2%) did not differ (p = NS). CONCLUSIONS: These results suggest that intravenous thrombolytic therapy might be preferred over coronary angioplasty for most patients because of the often shorter time to treatment.     

Thrombolysis for acute myocardial infarction

Thrombolytic therapy has been a major advance in the management of acute myocardial infarction. Unfortunately, it continues to be underused or is administered later than is optimal. Thrombolytic therapy works by lysing infarct artery thrombi and achieving reperfusion, thereby reducing infarct size, preserving left ventricular function, and improving survival. The most effective thrombolytic regimens achieve angiographic epicardial infarct-artery patency in only approximately 50% of patients within 90 minutes. Bleeding requiring transfusion occurs in approximately 5% of patients and stroke in approximately 1.8% with these regimens, which include adjunctive aspirin and intravenous heparin. There are several ways in which reperfusion rates and thus patient outcomes might be improved, such as different dosing regimens of established agents; combinations of different agents; improved adjunctive therapy such as direct antithrombin agents, low-molecular-weight heparin, or glycoprotein IIb/IIIa receptor antagonists; or the development of novel thrombolytic agents with enhanced fibrin specificity, resistance to native inhibitors, or prolonged half-lives allowing bolus administration. All of these strategies are being tested in clinical trials. The best approach currently is to administer thrombolytic therapy as soon as possible to all patients without contraindications who present within 12 hours of symptom onset and have ST-segment elevation on the ECG or new-onset left bundle-branch block, unless an alternative reperfusion strategy is planned.     

Long-term beneficial effect of late reperfusion for acute anterior myocardial infarction with percutaneous transluminal coronary angioplasty

BACKGROUND: Although the short-term and long-term beneficial effects of early coronary revascularization by primary PTCA or thrombolytic therapy have been established for acute myocardial infarction, thrombolytic therapy >24 hours after the onset of acute myocardial infarction has not been shown to improve clinical outcome. The purpose of this study was to assess the effect of late revascularization by primary PTCA over a 5-year period. METHODS AND RESULTS: Eighty-three patients with initial Q-wave anterior myocardial infarction >24 hours after onset were randomized into a PTCA group (n=44) and a no-PTCA group (n=39). Long-term follow-up was conducted with regard to end points, which included cardiac death, nonfatal recurrence of myocardial infarction, and development of congestive heart failure. Left ventricular ejection fraction and regional wall motion at 6 months after myocardial infarction were similar in the 2 groups. Left ventricular end-diastolic and end-systolic volume indexes were significantly smaller in the PTCA group than in the no-PTCA group (P<0.0001). With cardiac events as end points, a 5-year Kaplan-Meier event-free survival analysis revealed that the no-PTCA group had a worse prognosis than the PTCA group (P<0.0001). Patency of the infarct-related artery, left ventricular ejection fraction, end-diastolic volume index, and end-systolic volume index were significantly associated with cardiac events by a Cox proportional hazards analysis (hazard ratios 0.120, 0.845, 1.065, and 1.164, respectively). CONCLUSIONS: In initial Q-wave anterior myocardial infarction, we conclude that even with late reperfusion, PTCA had beneficial effects on cardiac events over the 5-year period after myocardial infarction, with the prevention of left ventricular dilation after myocardial infarction being a possible mechanism.     

Percutaneous transluminal coronary angioplasty in acute myocardial infarction. A prospective controlled study

In the present study we compared the outcome of primary percutaneous coronary angioplasty (PTCA) (PTCA without prior or concomitant administration of thrombolytic drugs) in 82 consecutive patients with acute myocardial infarction (AMI) with the outcome of 82 AMI patients, who were treated with intravenous thrombolysis. The thrombolysis patients were prospectively matched to the angioplasty patients regarding age, sex, duration of symptoms and infarct localisation. The in-hospital mortality was 3.7% in the PTCA group versus 4.9% in the thrombolysis group. Thrombolysis-treated patients had increased use of diuretics and ACE-inhibitors as compared to PTCA-treated patients. The mean ejection fraction was 52 +/- 11% in the PTCA group versus 47 +/- 10% (p = 0.01) in the thrombolysis group. We conclude that initial Danish experience with primary PTCA is promising, and that this treatment may favourably affect the outcome of acute myocardial infarction.     

Primary angioplasty using a urokinase-coated hydrogel balloon in acute myocardial infarction during pregnancy

A 38-year-old multigravid white female presented at 16 weeks gestation with an acute inferoposterolateral myocardial infarction. Emergent coronary angiography demonstrated a total proximal occlusion of a large dominant left circumflex artery with a filling defect at the site of the occlusion suggestive of thrombus. Primary angioplasty using a urokinase-coated hydrogel balloon resulted in successful recanalization of the vessel with restoration of normal TIMI Grade III flow and, most notably, apparent complete lysis of the intracoronary thrombus. After a subsequently uneventful pregnancy, a healthy baby was delivered.