Viability-Guided PCI After Acute MI Cuts Recurrence


BARCELONA — Dobutamine echocardiography performed a couple of days after nonrevascularized acute MI reliably distinguishes those patients likely to benefit from percutaneous coronary revascularization prior to hospital discharge from those who don't need PCI, Dr. Gerrit Veen said at a joint meeting of the European Society of Cardiology and the World Heart Federation.

The purpose of the imaging procedure in this situation is to identify patients who have viable—and therefore vulnerable—myocardium in the infarct area. They are the ones at high risk for reinfarction during the next 3–6 months during the post-MI recovery phase. Stenting their infarct-related artery as soon as possible is warranted.

On the other hand, patients without viable myocardium in the infarct zone are at little risk. They can be managed medically, added Dr. Veen of the VU University Medical Center, Amsterdam.

These were the key findings of the Viability-Guided Angioplasty After Acute Myocardial Infarction (VIAMI) trial. The 12-center Dutch randomized trial was the first-ever formal study of viability-guided revascularization in patients not undergoing primary PCI.

VIAMI involved 291 MI patients not treated by primary PCI. About half got thrombolytic therapy, while the remainder experienced spontaneous reperfusion and presented too late to be eligible for thrombolysis. All underwent dobutamine echocardiography when stabilized 2–3 days post MI.

The 216 patients who displayed viability—meaning two or more myocardial segments responded to dobutamine stimulation—were randomized to immediate PCI with stenting of the infarct-related artery, with interhospital transport if needed, or to a more conservative watchful-waiting approach with PCI reserved for those who developed ischemic symptoms. Patients without viability in the infarct zone were followed in a registry.

The primary study end point was the 6-month combined rate of death, recurrent MI, or unstable angina. It was 6.6% in the PCI group, a 59% risk reduction relative to the 15.5% rate in the watchful-waiting arm. The difference resulted from a marked disparity in unstable angina: 2.8% in the PCI group, compared with 11.8% with watchful waiting.

In addition, 17.3% of patients in the watchful-waiting arm underwent elective revascularization in 6 months. None in the PCI group did.

“We believe viability testing should become a standard tool in the clinical evaluation of patients in the first days after thrombolysis in acute MI patients without revascularization. And in patients with viability, revascularization should be considered prior to hospital discharge,” the cardiologist said.

The primary end point rate in registry participants lacking viable infarct-zone myocardium was low, 5.3%. “The message here is that when you don't have viability, it's not necessary to routinely do angioplasty,” Dr. Veen noted.

Discussant Dr. Carlo Di Mario of Royal Brompton Hospital, London, observed that the VIAMI message is out of step with the most recent European Society of Cardiology guidelines on management of acute MI, which call for angiography with an eye toward possible PCI within 24 hours in all patients.

He voiced concern that even a 2- to 3-day delay for viability testing as in VIAMI could be sufficient to lose two-thirds of the benefit provided by a routine early invasive strategy.

But other observers were impressed with the efficiency of the Dutch strategy, which offers a more selective approach than the current popular practice of performing routine PCI in all in order to protect the 20%–30% who would otherwise develop recurrent ischemia during the post-MI recovery phase.

The VIAMI trial was funded by the Netherlands Heart Foundation, Eli Lilly, Boehringer Ingelheim, and Bristol-Myers Squibb.

In acute MI patients with viability, revascularization should be considered prior to hospital discharge. Dr. Veen

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