Introduction
Worldwide, the majority of patients who are admitted to the hospital with acute myocardial infarction (MI) are treated with thrombolysis or receive no reperfusion therapy because of late presentation. In the ensuing months 20-30% of patients suffer from recurrent ischemic events because of plaque-instability in the infarct-related coronary artery. Thus, after initial salvage of myocardium - being the primary goal of thrombolytic therapy - the rescued, viable myocardium is at risk for recurrent ischemia and necrosis. Several studies have indeed shown that after thrombolysis patients with residual viability in the infarct-area are at increased risk of recurrent ischemia or reinfarction. Management of post-MI patients with viability has never been studied in a randomised trial. Therefore, in current clinical practice viability is not used as tool for risk-assessment and patient management.
The VIAMI trial
In the VIAMI trial we sought to determine if patients with acute myocardial infarction who were treated with thrombolysis or who were too late for reperfusion therapy would benefit from stenting of the infarct-related coronary artery when they had viability in the infarct-area. Patients without viability were studied as an observational group to determine the risk of ischemia in contemporary medicine. Low-dose dobutamine echocardiography was used as viability test and was carried out 2–3 days after the acute event. Only stable patients were allowed to participate. Patients with improvement in two or more myocardial segments were classified as viable. Otherwise, patients were considered non-viable.
By protocol, patients with viability were randomised to an invasive or a conservative treatment strategy. In the invasive arm patients were scheduled for stenting of the infarct-related artery as soon as possible with concomitant use of abciximab. In the conservative group an ischemia-guided approach was used and angioplasty was only performed when indicated by recurrent signs and/or symptoms of ischemia.
Results
A total of 293 patients were included in the trial. Of these, 216 patients showed viability in the infarct-area and were randomised and 75 patients showed no viability (registry group). The primary endpoint of the study was the composite of death, recurrent MI and unstable angina at 6 months follow-up. In the 106 patients randomised to the invasive strategy 73% actually underwent culprit-vessel stenting with the use of abciximab. Another 11% was treated with coronary bypass grafting and in 16% revascularisation was not indicated.
The primary endpoint was reached in 6.6% of patients in the invasive group and in 15.5% in the conservative group. This is a relative risk-reduction of 59% in favour of the invasive strategy (p=0.04; hazard-ratio 0.41). The reduction was mainly driven by a significant reduction in ischemic events (Table 1). When elective revascularisations (not driven by a primary endpoint) were added to the analysis, event-rate in the invasive group at 6 months was 6.6% and in the conservative group 32.7% with a relative risk-reduction of 82% (p<0.0001; hazard-ratio 0.18).
The sum of all revascularisation-procedures performed during 6 months follow-up was 4.7% in the invasive group and 23.7% in the conservative group (p<0.0001). Finally, at 6 months a low rate of ischemia was found in the non-viable group (5.3%) in comparison to the viable-conservative group (14.5%). (p<0.05; hazard-ratio 0.35).
Conclusion
The VIAMI trial is the first randomised trial to show that after acute myocardial infarction (treated with thrombolysis or without reperfusion therapy) patients with viability in the infarct-area significantly benefit from a strategy of early in-hospital stenting of the infarct-related coronary artery (with the use of abciximab). This treatment results in a clear reduction in ischemic events and a long-term uneventful clinical course. Furthermore, the study confirmed that the risk of recurrent ischemia is low in patients without viability.
Personal reporters opinion
Patients with viability after MI who are conservatively managed (ischemia-guided) have frequent readmissions to the hospital with unstable angina or recurrent MI and also have a great need for revascularisation-procedures. Almost all of this can be prevented with early in-hospital stenting of the infarct-related coronary artery (or bypass surgery when indicated).
Thus, viability testing should become a standard tool in the clinical evaluation of patients in the early phase after thrombolysis for acute myocardial infarction and also in patients with ST-elevation MI who did not receive reperfusion therapy. Patients with viability should be considered for revascularisation before hospital-discharge.
In the absence of viability, revascularisation does not seem indicated for the prevention of recurrent ischemia.
Presentation available
Introduction
Worldwide, the majority of patients who are admitted to the hospital with acute myocardial infarction (MI) are treated with thrombolysis or receive no reperfusion therapy because of late presentation. In the ensuing months 20-30% of patients suffer from recurrent ischemic events because of plaque-instability in the infarct-related coronary artery. Thus, after initial salvage of myocardium - being the primary goal of thrombolytic therapy - the rescued, viable myocardium is at risk for recurrent ischemia and necrosis. Several studies have indeed shown that after thrombolysis patients with residual viability in the infarct-area are at increased risk of recurrent ischemia or reinfarction. Management of post-MI patients with viability has never been studied in a randomised trial. Therefore, in current clinical practice viability is not used as tool for risk-assessment and patient management.
The VIAMI trial
In the VIAMI trial we sought to determine if patients with acute myocardial infarction who were treated with thrombolysis or who were too late for reperfusion therapy would benefit from stenting of the infarct-related coronary artery when they had viability in the infarct-area. Patients without viability were studied as an observational group to determine the risk of ischemia in contemporary medicine. Low-dose dobutamine echocardiography was used as viability test and was carried out 2–3 days after the acute event. Only stable patients were allowed to participate. Patients with improvement in two or more myocardial segments were classified as viable. Otherwise, patients were considered non-viable.
By protocol, patients with viability were randomised to an invasive or a conservative treatment strategy. In the invasive arm patients were scheduled for stenting of the infarct-related artery as soon as possible with concomitant use of abciximab. In the conservative group an ischemia-guided approach was used and angioplasty was only performed when indicated by recurrent signs and/or symptoms of ischemia.
Results
A total of 293 patients were included in the trial. Of these, 216 patients showed viability in the infarct-area and were randomised and 75 patients showed no viability (registry group). The primary endpoint of the study was the composite of death, recurrent MI and unstable angina at 6 months follow-up. In the 106 patients randomised to the invasive strategy 73% actually underwent culprit-vessel stenting with the use of abciximab. Another 11% was treated with coronary bypass grafting and in 16% revascularisation was not indicated.
The primary endpoint was reached in 6.6% of patients in the invasive group and in 15.5% in the conservative group. This is a relative risk-reduction of 59% in favour of the invasive strategy (p=0.04; hazard-ratio 0.41). The reduction was mainly driven by a significant reduction in ischemic events (Table 1). When elective revascularisations (not driven by a primary endpoint) were added to the analysis, event-rate in the invasive group at 6 months was 6.6% and in the conservative group 32.7% with a relative risk-reduction of 82% (p<0.0001; hazard-ratio 0.18).
The sum of all revascularisation-procedures performed during 6 months follow-up was 4.7% in the invasive group and 23.7% in the conservative group (p<0.0001). Finally, at 6 months a low rate of ischemia was found in the non-viable group (5.3%) in comparison to the viable-conservative group (14.5%). (p<0.05; hazard-ratio 0.35).
Conclusion
The VIAMI trial is the first randomised trial to show that after acute myocardial infarction (treated with thrombolysis or without reperfusion therapy) patients with viability in the infarct-area significantly benefit from a strategy of early in-hospital stenting of the infarct-related coronary artery (with the use of abciximab). This treatment results in a clear reduction in ischemic events and a long-term uneventful clinical course. Furthermore, the study confirmed that the risk of recurrent ischemia is low in patients without viability.
Personal reporters opinion
Patients with viability after MI who are conservatively managed (ischemia-guided) have frequent readmissions to the hospital with unstable angina or recurrent MI and also have a great need for revascularisation-procedures. Almost all of this can be prevented with early in-hospital stenting of the infarct-related coronary artery (or bypass surgery when indicated).
Thus, viability testing should become a standard tool in the clinical evaluation of patients in the early phase after thrombolysis for acute myocardial infarction and also in patients with ST-elevation MI who did not receive reperfusion therapy. Patients with viability should be considered for revascularisation before hospital-discharge.
In the absence of viability, revascularisation does not seem indicated for the prevention of recurrent ischemia.
Presentation available
Session Number : 709007
Session Title: Hotline II
Conclusion
DISCUSSANT: Prof. Carlo Di Mario. Royal Brompton Hospital, London.
This important study by Veen et al addresses one of the most controversial points of the recently published first ESC guidelines for PCI coordinated by Prof Silber: What to do after successful thrombolysis?
The current ESC guidelines strongly recommends sending all these patients to angiography and possible PTCA, but this choice remains controversial, sparkling one of the few major discrepancies between ESC and American guidelines.
The solution proposed in this study is the universal use of low dose dobutamine to screen these patients and the utilisation of stent implantation in all the patients with viability.
The main limitation of the study is the inclusion of an equal number of pts who have been treated with thrombolysis and who have received no reperfusion treatment, two groups very heterogeneous in terms of coronary patency and myocardial viability (SLIDE 1).
The second main criticism is that the 48-72 hrs delay before low dose dobutamine echocardiography and the following 24 hours before PTCA negate more than half of the potential benefit stenting offers to pts with successful thrombolysis, as shown by the cumulative 30 day survival curves from GRACIA 1, SIAM III and CAPITAL-AMI (SLIDE 2).
Finally, the difference in the primary composite ischaemic end-point is only due to a reduction of unstable angina and you may argue whether utilisation of PTCA in all the patients with proven viability is a cost-effective strategy to prevent a “soft” end-point such as unstable angina with an absolute difference of only 9% in the first 6 months and no significant difference in recurrent MI and death.
Presentation available