Pre-operative Diagnosis of Silent Coronary Ischaemia May Reduce Post-operative Death and Myocardial Infarction and Improve Survival of Patients Undergoing Lower Extremity Surgical Revascularisation.

Abstract

Patients undergoing peripheral vascular surgery have increased risk of death and myocardial infarction (MI), which may be due to unsuspected (silent) coronary ischaemia. The aim was to determine whether pre-operative diagnosis of silent ischaemia using coronary computed tomography (CT) derived fractional flow reserve (FFR_CT) can facilitate multidisciplinary care to reduce post-operative death and MI, and improve survival. This was a single centre prospective study with historic controls. Patients with no cardiac symptoms undergoing lower extremity surgical revascularisation with pre-operative coronary CTA-FFR_CT testing were compared with historic controls with standard pre-operative testing. Silent coronary ischaemia was defined as FFR_CT ≤ 0.80 distal to coronary stenosis with FFR_CT ≤ 0.75 indicating severe ischaemia. End points included cardiovascular (CV) death, MI, and all cause death through one year follow up. There were no statistically significant differences between CT angiography (CTA-FFR_CT) (n = 135) and control (n = 135) patients with regard to age (66 ± 8 years), sex, comorbidities, or surgery performed. Coronary CTA showed ≥ 50% stenosis in 70% of patients with left main stenosis in 7%. FFR_CT revealed silent coronary ischaemia in 68% of patients with severe ischaemia in 53%. The status of coronary ischaemia was unknown in the controls. At 30 days, CV death and MI in the CTA-FFR_CT group were not statistically significantly different from controls (0% vs. 3.7% [p = .060] and 0.7% vs. 5.2% [p = .066], respectively). Post-operative coronary revascularisation was performed in 54 patients to relieve silent ischaemia (percutaneous coronary intervention in 47, coronary artery bypass graft in seven). At one year, CTA-FFR_CT patients had fewer CV deaths (0.7% vs. 5.9%; p = .036) and MIs (2.2% vs. 8.1%; p = .028) and improved survival (p = .018) compared with controls. Pre-operative diagnosis of silent coronary ischaemia in patients undergoing lower extremity revascularisation surgery can facilitate multidisciplinary patient care with selective post-operative coronary revascularisation. This strategy reduced post-operative death and MI and improved one year survival compared with standard care.