VIENNA — Immediate transfer for percutaneous coronary intervention after successful thrombolytic therapy in patients with ST-elevation MI provides markedly better outcomes than does a more conventional strategy of continued medical treatment in the non-PCI hospital, with transfer for rescue PCI only in the event of continued ST elevation at 90 minutes, Dr. Carlo Di Mario reported at the annual congress of the European Society of Cardiology.
This was the key finding of the Combined Abciximab Reteplase Stent Study in Acute Myocardial Infarction (CARESS in AMI). The three-country European trial compared two strategies for managing ST-segment elevation myocardial infarction (STEMI) patients for whom the preferred treatment—primary PCI—is anticipated to be unavailable within 90 minutes of their presentation at a non-PCI hospital.
CARESS involved 600 such patients who received half-dose reteplase, abciximab, aspirin, and unfractionated heparin. They were then randomized to immediate transfer for PCI or to transfer for rescue PCI only in the event of continued ST elevation at 90 minutes, which occurred in 36% of patients assigned to that study arm, explained Dr. Di Mario of Royal Brompton Hospital, London.
The primary study end point was a composite of death, repeat MI, or refractory ischemia at 30 days. The rate was 4.1% in the immediate transfer/PCI-for-all group, compared with 11.1% in the rescue PCI group. That's a 63% relative risk reduction in favor of the immediate-transfer strategy, noted Dr. Di Mario, a CARESS coprincipal investigator.
Patients averaged 170 minutes from onset of chest pain to reteplase. The median time from reteplase to PCI was 136 minutes in the immediate transfer group and 212 minutes in the rescue PCI patients.
Although the rate of any bleeding was significantly increased in the immediate transfer/PCI-for-all group—12.2% compared with 7.4%—severe bleeding and intracranial hemorrhages were rare and not significantly different between the two study arms.
“I believe this was due to the exclusion of patients at high risk of bleeding,” he commented. “This is a strategy for patients under 75 years old who have high-risk MIs and a low risk of bleeding.”
Indeed, the mean age of study participants was just 60 years.
Discussant Dr. Freek W.A. Verheugt noted that CARESS is the fourth study to show that STEMI patients should routinely undergo early PCI following successful lytic therapy. All four trials were small to moderate in size.
Where do things stand with respect to STEMI management in 2007 in light of CARESS and other recent studies? If PCI can be performed by experienced operators within 90 minutes of patient presentation, the treatment of choice is clearly primary PCI. If primary PCI within 90 minutes isn't available, a lytic should be given. If it doesn't accomplish reperfusion, urgent transfer for rescue PCI is warranted, said Dr. Verheugt, professor and chairman of the department of cardiology at University Hospital, Nijmegen, the Netherlands.
Even if there is reperfusion, however, PCI is still clearly necessary as shown in CARESS and three other trials. The key question is, when should it be done? That's unresolved. CARESS showed excellent outcomes with an average interval between lytic therapy and PCI of about 21/4 hours. That brief an interval could be tough to duplicate in clinical practice, especially for patients who present to hospitals in remote areas. At the other extreme, the Spanish GRACIA-1 trial showed similar benefits with a 17-hour interval, which is a lot more convenient for patients, transport crews, and cath lab personnel than a rushed dead-of-night transfer, he continued.
“We need a randomized trial of early versus late transport for auxiliary PCI in patients who are reperfused and stable after lytic therapy,” Dr. Verheugt concluded.
CARESS was sponsored by the Italian Society of Interventional Cardiology, with grants from Eli Lilly & Co. and Biotronik AG.
'This is a strategy for patients under 75 years old who have high-risk MIs and a low risk of bleeding.' DR. DI MARIO