NEW YORK (Reuters Health) – Cardiologists should perform percutaneous coronary intervention (PCI) as soon as possible if initial treatment for ST-segment elevation myocardial infarction (STEMI) is thrombolysis, researchers suggest.

A report in the July issue of the American Heart Journal showed that postponing PCI for a few days after thrombolysis didn’t jeopardize left ventricular function at 3 months in a cohort of relatively low risk patients. However, earlier data from the same cohort showed that clinical outcomes were worse at 12 months. (See Reuters Health story of September 24, 2009).

Furthermore, a meta-analysis published online on July 2nd in the European Heart Journal “showed that early routine PCI after fibrinolysis in STEMI patients significantly reduced reinfarction and recurrent ischemia at 1 month, with no significant increase in adverse bleeding events compared to standard therapy,” co-author Dr. Sigrun Halvorsen, from Oslo University Hospital Ullevaal, Norway, told Reuters Health in an email.

Primary PCI performed within 90 to 120 minutes is the preferred treatment for STEMI. But when long transport time makes timely PCI impossible, guidelines recommend thrombolysis. Researchers have not settled the issue of the best strategy after thrombolysis.

Dr. Halvorsen pointed out that “the advantages with an early invasive strategy are a reduction in reinfarction rate and in the rate of new ischemic events. The risk associated with early PCI after thrombolysis for STEMI is a higher frequency of bleedings, and also of other PCI-related complications if PCI is performed very early after thrombolysis.”

The NORDISTEMI study included 266 patients who had transfer delays to PCI of more than 90 minutes. Clinicians treated all of them with aspirin, tenecteplase, enoxaparin, and clopidogrel, and randomly assigned 134 to an early invasive strategy and 132 to a late invasive strategy.

With the early protocol, patients were transferred to the PCI center as soon as possible for immediate coronary angiography and PCI if indicated. Patients assigned the late protocol underwent urgent angiography only in the absence of reperfusion with thrombolysis. Otherwise, their doctors told them to have angiography within 2 to 4 weeks.

Median time from lysis to angiography was 130 minutes in the early group and 4 days in the late group. Eighty-nine percent of those treated right away underwent PCI versus 75% of those treated later. Doctors assessed left ventricular function at 3 months for 123 patients in the early group and 118 in the late group

Both strategies preserved left ventricular volumes and function, which was “literally identical in the 2 treatment groups when extensively investigated with different imaging modalities,” the investigators report.

One potential reason for this is that “the left ventricular function was surprisingly normal in both groups, making it difficult to detect smaller differences between groups,” Dr. Halvorsen explained. “The very early treatment with thrombolysis (within 2 hours from symptom onset in 50% of patients) was probably the most important contributing factor for the high median EF values.”

According to Dr. Vincent Bufalino, CEO of Midwest Heart Specialists in Chicago and past board member of the American Heart Association, “This was a very select study looking at a narrow population. They all had good hearts to start with, so it’s no surprise that there was no difference (in ventricular function) at 3 months.” Dr. Bufalino was not involved in the research.

However, the composite endpoint of death, stroke, or reinfarction at 12 months occurred in 6% of patients in the early group vs 16% in the late group (p = 0.01).

The authors note that their findings can’t be extended to patients with severely reduced left ventricular function following STEMI

The meta-analysis, also co-authored by Dr. Halvorsen, included seven trials in which 2961 patients who had undergone successful fibrinolysis were randomized to early routine PCI or to PCI only in cases without evidence of reperfusion.

Early routine PCI reduced the rate of reinfarction (odds ratio 0.55, p = 0.003), the combined endpoint of death/reinfarction (OR 0.65, p = 0.004) and recurrent ischemia (OR 0.25, p < 0.001). These benefits were maintained at 6 to 12 months, the investigators report. Rates of major bleeding events and stroke were similar between the two groups. “I recommend the early invasive strategy,” Dr. Halvorsen concluded. “With modern adjunctive anti-thrombotic medication and use of the radial approach, the risk of bleedings and other PCI-related complications were few in our study.” However, the more pertinent issue, Dr. Bufalino told Reuters Health, is getting patients to facilities where PCI can be done without delay so thrombolysis isn’t needed. “In the US at least, almost everyone is just a helicopter ride away from a cath lab, so PCIs can be performed within 90 minutes.” Am Heart J 2010;160:73-79. Eur Heart J 2010.