Partial Anterior Papillary Muscle Rupture Due to Diagonal Branch Occlusion

A 72-year-old man in cardiogenic shock was referred to hospital for partial papillary muscle rupture (PMR). Emergency intra-aortic balloon pumping and veno-arterial extracorporeal membrane oxygenation were initiated. Coronary artery angiography revealed total occlusion and severe stenosis of the first and second diagonal branches (Figure A). Moreover, left ventriculography (Figure B), transthoracic echocardiography (Figure C1,C2) and transesophageal echocardiography (Supplementary Movie) revealed an anterior PMR and severe mitral regurgitation (MR). Therefore, the patient underwent emergency mitral valve replacement.

Figure.

(A) Coronary artery angiography shows total occlusion and severe stenosis of the first (upper yellow arrow) and second (lower yellow arrow) diagonal branches. (B) Left ventriculography and (C1,C2) transthoracic echocardiography show severe mitral regurgitation. (D) Gross and (E) histological (H&E, ×400) pathology demonstrate inflammatory changes of the anterior mitral valve leaflet (upper yellow arrow) and anterior papillary muscle (lower yellow arrow).

Gross pathologic examination showed inflammatory changes in the middle scallop of the anterior leaflet and papillary muscle (Figure D), and histological examination revealed acute coagulative necrosis of the anterior papillary muscle with inflammatory cell infiltration and fibrous organization (Figure E). The anterior papillary muscle has dual blood supply from the left anterior descending artery and the diagonal or marginal branch of the left circumflex artery. Therefore, anterior PMR is extremely rare,¹ and PMR due to diagonal branch occlusion is even rarer.² The present case is uncommon because a single diagonal branch occlusion caused a partial rupture of the anterior papillary muscle due to acute myocardial infarction-induced severe MR.

Disclosures

The authors declare no conflicts of interest.

Supplementary Files

Supplementary Movie. Transesophageal echocardiography shows partial anterior papillary muscle rupture and severe mitral valve regurgitaiton.

Please find supplementary file(s);

http://dx.doi.org/10.1253/circj.CJ-22-0391

References

• 1.   Damluji AA, van Diepen S, Katz JN, Menon V, Tamis-Holland JE, Bakitas M, et al. Mechanical complications of acute myocardial infarction: A Scientific Statement from the American Heart Association. Circulation 2021; 13: e16–e35.
• 2.   Okamoto Y, Minakata K, Yunoki T, Katsu M. Complete rupture of the anterolateral papillary muscle complicated with acute myocardial infarction due to diagonal branch occlusion. J Cardiol Cases 2012; 5: e76–e79.