MRI evaluation of a coronary artery perforation

1. Case history 

A 75-year-old man with a past medical history of hyperlipidemia, hypertension, chronic renal insufficiency, and chronic obstructive pulmonary disease was electively admitted for cardiac catheterization due to angina and evidence of myocardial ischemia on nuclear stress test imaging. The diagnostic left heart catheterization demonstrated severe obstructive disease of the proximal circumflex, as well as a diffusely diseased heavily calcified right coronary artery (RCA). Anticoagulation was commenced using heparin. First, the circumflex lesion was successfully treated without complication by intravascular ultrasound (IVUS) guided stenting, using a sirolimus-coated stent (3.0×18 mm Cypher, Guidant). Percutaneous intervention of the RCA was then undertaken. After successfully crossing the lesion with a 0.014 in. balanced medium weight wire (Guidant), IVUS of the RCA was attempted but failed due to inability to cross the lesions with an Atlantis IVUS catheter. Therefore, percutaneous coronary intervention (PCI) with rotational atherectomy (Rotablator, Boston Scientific) was undertaken using a 1.75 burr over a 0.09 in. Rota floppy wire. The RCA angiogram immediately after rotational atherectomy revealed contrast media extravasation consistent with a coronary perforation of the mid RCA (Grade III; Fig. 1). Prolonged occlusion with a 2.5×15 mm Maverick balloon failed to control the perforation. Several attempts to place a covered stent (JoStent, Boston Scientific) were unsuccessful due to the inability to cross the lesion. The perforation was successfully controlled by placement of a bare metal stent (2.5×24 mm S660 OTW). During the immediate post-PCI period the patient required pericardiocentesis due to hypotension and early signs of cardiac tamponade. Twenty-four hours after PCI, the patient was brought back to the cardiac catheterization lab for a follow-up angiogram (Fig. 2). Seventy-two hours later, a cardiac MRI was performed for further evaluation (Fig. 3, Fig. 4). After a short hospitalization, the patient was discharged home in stable condition.

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Fig. 1. RCA angiogram immediately after rotational atherectomy (Rotablator). The arrow points to the area of perforation in the mid segment of the RCA evidenced by contrast extravasation.

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Fig. 2. RCA angiogram follow up at 24 h.

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Fig. 3. Four-chamber delayed hyperenhancement 3-D image (20 min postgadolinium). The arrow points to the myocardial hematoma seen in the AV groove without evidence of postgadolinium enhancement after delayed injection.

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Fig. 4. Short axis cine MRI image of the LV and RV in cross-section. The red arrow points to an area of normal appearing RV free wall myocardium (roof of RV). The blue arrow indicates the area of RV free wall thickening with clot and blood, as well as clot and blood within the pericardial space. The signal is heterogeneous due to differing tissue characteristics in this area, indicative of clot at differing stages of coagulation and myocardium. The RV myocardium is thickened in this region as compared with the normal region indicated by the red arrow.

This case highlights the technical challenges of treatment of calcified and tortuous lesions and the inability to successfully use covered stents in all cases. It also demonstrates the utility of MRI to evaluate the extension of myocardial hematoma after coronary perforations. Fortunately, in this case, with a bare metal stent, we could contain the extravasation of blood into the pericardial cavity.