Opening a blocked artery during a heart attack is one of modern medicine's greatest achievements, and rapid reperfusion to restore blood flow remains the gold standard for saving lives. But new imaging research led by the Medical Imaging Research Institute’s Cardiovascular Imaging Research Center at Indiana University School of Medicine suggests that in a subset of patients, the story and the risk doesn't end in the catheterization lab — and further investigation and intervention is needed.
According to cardiovascular imaging researcher Keyur P. Vora, MD, director of CIRC at IU School of Medicine, a second, more volatile emergency risk could unfold inside the heart muscle that current routine evaluation may not fully capture.
The condition, called intramyocardial hemorrhage (IMH), is bleeding that occurs within the heart muscle after blood flow is restored. It affects more than 40% of heart attack patients who undergo emergency artery-opening procedures.
“In many cases, IMH resolves without consequence,” Vora said. “But when a severe case emerges, IMH can trigger a chain of mechanical events that could lead to heart failure and death.”
Measured IMH shows brunt force
New findings published in JACC: Case Reports show that extensive IMH generates an intense internal “tug of war” in and around the heart muscle. The healthy heart wall contracts powerfully while the hemorrhagic, damaged segment stretches in the opposite direction.
Authors of the case study measured the resulting shear force at nearly twice the level seen in typical heart attacks. That force can tear the heart's inner lining and expose a raw surface that becomes a highly potent trigger for blood clot formation — a mechanism entirely separate from the classic post-heart attack clot, which forms due to sluggish blood flow in a weakened ventricle.
“This distinction matters clinically,” said co-author Rohan Dharmakumar, PhD, executive director of the Medical Imaging Research Institute and vice chair of research for the Department of Radiology and Imaging Sciences at IU School of Medicine.
“A clot anchored to a structural wound in the heart wall behaves differently from one resting on a slow-moving pool of blood in its morphology, its persistence and potentially its response to blood thinners,” Dharmakumar explained. “Recognizing which type is present directly shapes how aggressively blood pressure should be controlled, how anticoagulation should be balanced and how closely the patient needs to be followed.”
With hemorrhagic heart attacks carrying nearly a three-fold higher in-hospital mortality rate, identifying these patients early and understanding the full extent of their injury is necessary to deploy the next frontier in optimizing STEMI care after successful reperfusion.
