Aims: Our aim was to follow changes in myocardial function and physiology in patients awaiting coronary artery bypass surgery (CABG) and relate changes to post-revascularisation functional response. Methods: and results In 21 patients with CAD and LV dysfunction, myocardial glucose utilisation (MGU) and blood flow (MBF) were measured with positron emission tomography using F-18-fluorodeoxyglucose and oxygen-15-labelled water. Left ventricular function, MGU, and MBF were re-assessed after one year, immediately prior to CABG. At baseline, dysfunctional myocardium displayed a reduction in MGU, hyperaemic MBF, and coronary vasodilator reserve (CVR) compared to normally functioning muscle. In the year preceding CABG, the overall wall motion score index increased (2. 09 ± 0.65 vs. 2.3 ± 0.7, p = 0.0001) and the LV ejection fraction decreased (30.6 ± 11.1% vs. 27.3 ± 11.5%, p <0.001). LVEF fell in 14 patients (28.7 ± 9.4 vs. 23.8, p <0.0001). Aggregate regional wall motion worsened in 15 patients. In contrast to myocardium displaying stable function at echocardiography, myocardium with evidence of deterioration showed a parallel decrease in hyperaemic MBF and CVR (1.57 ± 0.67 vs. 1.19 ± 0.7 ml/min/g, [p = 0.004] and 1.9 ± 0.75 vs. 1.33 ± 0.6, [p = 0.005], respectively). Such myocardium displayed attenuated recovery postoperatively (21/68 [31%] LV segments) versus 'waiting-time' stable myocardium (98/169 [58%], p = 0.0002). Conclusion: Delayed revascularisation in ischaemic left ventricutar impairment results in declining function and a reduced likelihood of contractile improvement.
- Blood flow
- Coronary disease
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine