Sextuple Coronary Bypasses

Matthias May, MD
Department of Radiology, University Hospital Erlangen, Erlangen, Germany
 |  19-12-2019

History

A 60-year-old male patient, who had undergone multiple coronary artery bypass graft (CABG) and thromboendarterectomy (TEA) surgery 10 years ago, returned for a follow-up due to atypical chest pain. A coronary CT angiography (CTA) was performed for evaluation.

Diagnosis

Coronary CTA images revealed three bypass grafts with sixfold coronary anastomoses. A left internal mammary artery (LIMA) graft, originating off the left subclavian artery, was anastomosed side-to-side to the second diagonal branch (D2) of the left anterior descending artery (LAD) and end-to-side to the distal LAD. A free right internal mammary artery (RIMA) graft, originating from the anterior wall of the ascending aorta, had been laid over the main pulmonary artery and was anastomosed side-to-side to the middle of the first diagonal branch (D1) of the LAD and the first marginal branch (M1) of the left circumflex artery (LCX). A large third marginal (M3) branch of the LCX was also anastomosed end-to-side to the RIMA graft. A right saphenous vein graft (SVG), originating next to the free RIMA graft from the ascending aorta, was anastomosed end-to-end to the distal right coronary artery (RCA). All grafts and anastomoses remained patent, with no evidence of stenosis or occlusion. The original left main coronary artery (LM), LAD, LCX and RCA showed severe stenoses caused by mixed plaques in the proximal segments.

Fig. 1:
Curved MIP images show a LIMA to the D2 and the distal LAD (Fig. 1a, arrows), a SVG to the distal RCA (Fig. 1b, arrow), and a free RIMA to the D1 (Figs. 1c and 1d, arrows), M1 (Figs. 1c and 1d, dotted arrows), and M3 (Fig. 1c, arrowhead). All grafts and anastomoses are patent.

Fig. 2:
cVRT images demonstrate the patency of the sextuple bypasses and anastomoses in three dimensions.

Comments

CABG surgery is performed to bypass the diseased coronary arteries using arterial or venous grafts. A sextuple bypass is considered to be the most intricate and surgically challenging, especially when a free arterial RIMA graft is reserved for complex anatomy and advanced diseases, such as in this case. The long-term clinical outcome depends upon the patency of the CABG, particularly that of the vulnerable venous grafts. Coronary CTA is non-invasive and depicts the entire course of the grafts in both curved maximum intensity projection (MIP) and 3D cinematic volume rendering technique (cVRT). In CABG cases, it is however essential, as well as technically challenging, to provide good image quality for evaluation of the vessel lumen due to the large volume coverage and the presence of calcifications and clip material. In this case, the coronary CTA was performed with a SOMATOM X.cite, which provides both sophisticated hardware and intelligent software support. Optimal image quality can hence be achieved not only in standard patients but in exceptional cases as well.

Examination Protocol

ScannerSOMATOM X.cite
Scan areaHeart
Scan modeProspective ECG triggered sequential scan
Scan length206 mm
Scan directionCranio-caudal
Scan time10.3 s
Tube voltage120 kV
Effective mAs112 mAs
Dose modulationCARE Dose4D
CTDIvol13.8 mGy
DLP286 mGy cm
Rotation time0.3 s
Slice collimation128 x 0.6 mm
Slice width0.8 mm
Reconstruction increment0.3 mm
Reconstruction kernelBv40 and Bv48 (ADMIRE 3)
Heart rate48 - 52 bpm
Contrast350 mg/mL
Volume70 mL + 50 mL saline
Flow rate5 mL/s
Start delayTest bolus + 2 s