Magnetic resonance imaging in coronary artery bypass surgery – improvement of global and segmental function in patients with severely compromized left ventricular function

Matthias Thielmann¹, Peter Hunold², Claudia Böhm¹, Parwis Massoudy¹, Heinz Jakob¹

¹Department of Thoracic and Cardiovascular Surgery (M.T., P.M., H.J.), West-German Heart Center Essen, University Hospital Essen; ²Department of Diagnostic and Interventional Radiology (P.H.), University Hospital Essen, Essen, Germany

Objectives: In the present study, patients with severely compromized left ventricular function underwent magnetic resonance imaging (MRI) before and after coronary artery bypass grafting (CABG). Although improvement of global myocardial contractile function has been shown before, we sought to evaluate whether a functional contractile improvement may be determinable on a myocardial segmental basis after CABG surgery.

Methods: Thirty-three CABG patients with left ventricular ejection fraction (LVEF) ≤30% prospectively underwent MRI to compare pre- and postoperative functional data. At follow-up, all survivors underwent clinical assessment. In 16 patients (three patients died perioperatively, 13 could were lost to MRI follow-up because of cardiac resynchronization therapy and other reasons) postoperative MRI scanning was performed.

Results: In-hospital mortality was 9%. At 20 ± 2 months after surgery, New York Heart Association class improved from 3.0 ± 0.1 to 2.2 ± 0.2 (p < 0.01). Left ventricular end-diastolic volumes decreased significantly from 229 ± 14 mL to 189 ± 19 mL (p < 0.05). LV end-systolic volumes decreased significantly from 163 ± 13 mL to 126 ± 17 mL (p < 0.05). LVEF improved from 30 ± 2% to 36 ± 3% (p < 0.05). On a segmental basis, 42 out of 875 segments (4.8%) had normal function before surgery, at follow-up, 177 segments (20.4%) had normal regional function (p < 0.05).

Conclusions: Patients who undergo CABG surgery with severely compromized left ventricular function, postoperative MRI shows improved global and segmental cardiac function at mid-term follow-up. At the same time there is considerable clinical improvement.

Keywords: coronary artery bypass grafting, magnetic resonance imaging, left ventricular function, outcomes