Stenting of Spontaneous Coronary Artery Dissection From a Pathological Point of View
A 32-year-old female recently postpartum was admitted with chest pain and shortness of breath. She was diagnosed with acute inferior myocardial infarction and taken to catheterization laboratory in cardiogenic shock. The proximal right coronary artery was occluded, and an everolimus-eluting stent (Abbott Vascular, Santa Clara, CA) was implanted successfully. Left coronary angiography showed 50% stenosis of proximal left anterior descending (LAD) and total occlusion of left circumflex. The patient remained in cardiogenic shock despite insertion of an intra-aortic balloon pump and temporary pacemaker and died after cardiac arrest.
At autopsy (Figure [A]), coronary arteries showed no gross atherosclerosis, but diffuse coronary artery dissections, involving left main, LAD, left circumflex, and right coronary artery. The stent was implanted in the true lumen (TL, Figure [A3 through A5]), though it was not well expanded and the underlying dissection was still observed. The dissection in the right coronary artery extended both proximally and distally, but severe narrowing was only observed in the distal right coronary artery. The underlying vessel wall showed disorganization of the media with smooth muscle cell loss, fragmentation of elastic fibers, and increased proteoglycan deposition.
A 40-year-old female presented with acute coronary syndrome 1 week after delivering her second child. She had coronary artery dissection of the left main with extension into the distal LAD. Three everolimus-eluting stents were placed in the left main/LAD, and a separate stent was placed in left circumflex. Her left ventricular function deteriorated, and a left ventricular assist device was placed. Her condition stabilized, but 4 months later underwent orthotopic cardiac transplantation. The explanted heart with the stented coronary artery segments was submitted to our Institute for examination.
Histological examination of stented sections from the proximal and mid-LAD showed the presence of stent in the false lumen (Figure [B]) with collapse of the TL (Figure [B]). The stent was covered by neointimal tissue with an uneven distribution smooth muscle cells in proteoglycan matrix. In the left circumflex, the stent was within the TL; however, it was not fully expanded such that false lumen was still present (Figure [B5 through B8]). Neointimal tissue covered the stent struts in the TL, while the false lumen showed significant narrowing from the presence of a large number of smooth muscle cell in a proteoglycan matrix (Figure [B5 through B8]).
Stenting of spontaneous coronary artery dissection is challenging, and its effectiveness for this particular indication remains understudied. Here, we illustrate one case with acute poor outcome and the other that survived and received a cardiac transplant. Stenting must be considered with extreme caution because of the inability of distinguish TL from false lumen. Saw et al1 reported that revascularization of spontaneous coronary artery dissection is performed in 10% to 60% of patients, and >80% of these procedures are percutaneous coronary intervention. However, success rate for percutaneous coronary intervention is not high (50%–90%).1 Further research is required to understand the optimal treatment of these lesions.
Sources of Funding
The study was sponsored by CVPath Institute, a nonprofit organization dedicated to cardiovascular research.
CVPath Institute has research grants from Abbott Vascular, Atrium Medical, Boston Scientific, Biosensors International, Cordis—Johnson & Johnson, Medtronic, CardioVascular, OrbusNeich Medical, and Terumo Corporation. Dr Virmani has speaking engagements with Merck; receives honoraria from Abbott Vascular, Boston Scientific, Lutonix, Medtronic, and Terumo Corporation; and is a consultant for 480 Biomedical, Abbott Vascular, Medtronic, and W.L.Gore. Dr Finn has sponsored research agreements with Boston Scientific and Medtronic CardioVascular and is an advisory board member to Medtronic CardioVascular. Dr Mori has received honorarium from Abbott Vascular Japan, Goodman, and Terumo Corporation. The other authors report no conflicts.
- © 2016 American Heart Association, Inc.