Free-Wall Rupture Post–Reperfused Acute Myocardial Infarction
Insights From Multimodality Cardiovascular Imaging
A 37-year-old man presented with acute inferior ST-segment–elevation myocardial infarction (MI). His only risk factor for coronary artery disease was smoking. He underwent urgent x-ray coronary angiography, which showed a chronically occluded left anterior descending artery and recannulized right coronary artery. A bedside echocardiogram was performed to assess left ventricular function and any postinfarct complications. It demonstrated severely impaired left ventricular systolic function and an aneurysmal apex with a mobile intracavity mass (Figure 1A and 1B, online-only Data Supplement Movies I and II). Further views demonstrated hemopericardium suggesting concealed free-wall rupture (Figure 1B, purple arrow). An intramyocardial tear at the level of the midinferior wall (Figure 1B, red arrow) was suspected.
The patient underwent further investigations including ECG-gated cardiac computed tomography and cardiac magnetic resonance (CMR) imaging.
Multiparametric CMR provided further insight into the pathophysiology of the free-wall rupture (Figure 2, online-only Data Supplement Movie III). Cine CMR confirmed the anatomic findings with evidence of contained rupture of the inferior wall leading to the formation of a pseudoaneurysm. Native T1 mapping and T2-weighted images showed edema in the inferior wall suggesting acute inferior infarction. T2-weighted images were also suggestive of microvascular obstruction and intramyocardial hemorrhage within the acute infarct. The intramyocardial hemorrhage was seen to extend from the midseptum to the inferoseptum where the free-wall rupture occurred. Early contrast-enhanced CMR confirmed the presence of microvascular obstruction in the acute inferior infarct and demonstrated a large burden of thrombus within the pseudoaneurysm. Finally, late gadolinium enhancement showed a large chronic anterior infarct resulting in extensive anteroseptal wall scarring, extending into the inferoseptum.
In the current era of urgent reperfusion therapy for ST-segment–elevation MI, the incidence of myocardial free-wall rupture is very low (<2%).1 Nevertheless, it carries with it a substantial mortality rate varying between 39% and 100%.2 From registry-based data, several risk factors have been identified with uncertain roles.3 These include the following: female sex, advanced age, hypertension, first MI, and poor coronary collateralization.
As this case illustrates, the use of multimodality imaging and, in particular, multiparametric CMR allows insights into the pathogenesis of free-wall rupture in acute MI. Both intramyocardial hemorrhage and microvascular obstruction result in adverse remodeling of the left ventricle after myocardial infarction by reducing the tensile strength of the affected myocardium.4 Over time, high left ventricle pressures lead to adverse remodeling and localized dilation. In this case, an acute inferior infarct with intramyocardial hemorrhage in the borderzone of a large chronic anterior MI resulted in intramural dissection and free-wall rupture.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.115.018932/-/DC1.
- © 2015 American Heart Association, Inc.
- Moreno R,
- López-Sendón J,
- García E,
- Pérez de Isla L,
- López de Sá E,
- Ortega A,
- Moreno M,
- Rubio R,
- Soriano J,
- Abeytua M,
- García-Fernández MA