Opening a Completely Blocked Artery During a Heart Attack With Cardiogenic Shock: New Multicenter Data

A heart attack that sends the body into cardiogenic shock is one of the most dangerous emergencies in cardiology. Dr. Michael Megaly served as senior and corresponding author of a new multicenter study in the Canadian Journal of Cardiology that followed patients with this condition after a complex procedure to open a chronically blocked artery. Co-investigators included Drs. Khaldoon Alaswad, Stephane Rinfret, and Emmanouil Brilakis.

The problem

In cardiogenic shock, a heart attack has damaged the heart so severely that it cannot pump enough blood to keep the body's organs working. Treatment starts with opening the artery that caused the heart attack. Many of these patients also have other arteries narrowed or blocked, and some have a chronic total occlusion (CTO), an artery that has been completely blocked for months or years. A CTO can leave a large area of heart muscle short of blood flow just when the heart can least afford it.

Whether to open a CTO in this setting has remained an open question. Earlier trials compared treating only the artery that caused the heart attack against treating every blocked artery immediately, but they did not test CTO procedures specifically. More recent data suggest that treating additional arteries may help in selected patients, particularly when blood flow to the heart muscle stays poor after the main artery is open.

What the study looked at

The investigators used TriNetX, a research network that pools health records from 161 healthcare organizations. They identified 617 patients who underwent a CTO procedure while in cardiogenic shock between 2014 and 2025, and tracked their outcomes for up to five years. The average age was about 67, and two-thirds were men.

Many of these patients needed temporary mechanical heart support to stabilize them. About one in three received an intra-aortic balloon pump, and more than one in four received an Impella heart pump.

What they found

• 27 out of 100 patients died within 30 days.

• 34 out of 100 had died by one year.

• 40 out of 100 had died by five years.

• Within 30 days, 5.5% had a stroke, 7.8% needed a repeat procedure, and 2.0% needed bypass surgery.

Most of the risk came in the first month. Patients who got through that period faced a much lower rate of further events.

Why the operator matters

A 27% death rate at 30 days is serious. It is also lower than the near-50% figures reported in larger studies of cardiogenic shock. The study did not directly compare the two groups, so it cannot say the procedure caused the difference. The investigators point to two possible explanations: opening the blocked artery may restore blood flow to a large area of heart muscle, and these procedures are usually performed at experienced centers by advanced operators who use mechanical support early.

That second point is the practical one. A CTO procedure in a patient in shock is among the most technically demanding procedures in cardiology. It requires an operator with CTO expertise, the ability to place and manage mechanical support, and a team ready to do both at once. The study cannot separate the benefit of the procedure from the benefit of who performs it and where, but it raises a question that matters for these patients: whether an operator with that experience is available when the emergency happens.

The investigators note the study's limits, including a modest sample size, no comparison group, and an observational design. They conclude that treating large blocked arteries, including CTOs, may be worthwhile in carefully selected patients, and that further research is needed to define the role of this approach.

Doma M, Ramadan A, Cogar B, McEntegart MB, Mashayekhi K, Alaswad K, Rinfret S, Leibundgut G, Brilakis ES, Megaly M. Percutaneous Coronary Intervention for Chronic Total Occlusion in Acute Myocardial Infarction Complicated by Cardiogenic Shock. Can J Cardiol. 2026;42(7):1513-1515. doi:10.1016/j.cjca.2026.03.047

Dr. Michael Megaly specializes in complex and high-risk coronary interventions, chronic total occlusion (CTO) PCI, surgical turn-downs, complex peripheral artery disease, and limb salvage at Integris Health Heart Hospital in Oklahoma City.