Image of the Month - January 2016 - Acute onset chest pain and ST elevation

Submitted by Dr Yan Ning Neo, Dr Jonathan Weir-McCall
Ninewells Hospital and Dundee Medical School, UK

This 61 year old male presented with acute onset chest pain, and now onset ST elevation on his ECG on a background of prior left circumflex stenting several years previously for stable angina.  He was immediately transferred to the cath lab where engagement of the left coronary was technically challenging.  After stenting of the LMS, angiography continued to show marked irregularity of the left circumflex artery and complete occlusion of the LAD, and a markedly abnormal appearance of the aortic sinus.  In addition the right coronary artery could not be cannulated.  The suspicion of an aortic dissection was raised and the patient was transferred straight from the cath lab for an emergency ungated CT. 

The short axis view of the left ventricle (Figure A) demonstrates, even on this ungated exam, a transmural perfusion defect involving the anterior and septal walls consistent with LAD occlusion. Oblique axial (Figure B), and sagittal images (Figure C) of the aorta root show a highly unusual circumferential aortic dissection which involves both coronary ostia with the dissection flap intussuscepting into the ascending aorta.  Note is also made of the intra-aortic balloon pump on the oblique sagittal view (Figure C) where the CO2 filled tube is inflating and deflating during image acquisition.

2016 Jan IOTM

Diagnosis: Circumferential ascending aorta dissection with intimal intussusception with extension of the dissection into the left coronary artery causing a left anterior descending artery (LAD) infarct.

Circumferential intimal dissection as seen in this case is a rare but hazardous complication of aortic dissection, and is termed “intimo-intimal intussusception”.[1] Complications of this can arise due to the dissection flap extending into vessels such as the coronary ostia, or alternatively, unique to this kind of dissection, the cylindrical-shaped dissection flap can intussuscept proximally into the left ventricle outflow tract during diastole causing coronary ostia occlusion and potentially severe aortic valve insufficiency.[2] Complete or persistent coronary malperfusion can then lead to myocardial infarction as seen in the current case.[3]

References:

  1. Hufnagel CA, Conrad PW. Intimo-intimal intussusception in dissecting aneurysms. Am J Surg. 1962:103:727-31
  1. Whitley W, Tanaka KA, Chen EP et al. Acute aortic dissection with intimal layer prolapse into the left ventricle. Anesth Analg. 2007;104(4):774-6
  1. Lentini S, Sossio Perrotta. Aortic dissection with concomitant acute myocardial infarction: From diagnosis to management. J Emerg Trauma Shock. 2011;4(2):273-8.