19 Association between exercise time, quantitative coronary angiography and CMR ischaemia burden: a CE-MARC sub study

<h3>Introduction</h3> Recent sham-controlled trials have suggested that percutaneous coronary intervention (PCI) has little effect on exercise time in patients with angina.¹ We aimed to investigate the relationship between ischaemia burden and exercise capacity in patients with stable angina by using data from Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease (CE-MARC)² in which patients underwent stress perfusion cardiovascular magnetic resonance (CMR), treadmill exercise stress testing and quantitative coronary angiography (QCA). <h3>Materials and Methods</h3> In this analysis 525 patients with suspected angina and complete data were analysed. Ischaemic segments on CMR were assessed visually by comparing adenosine stress and late gadolinium enhancement images.³ Maximum and cumulative coronary stenosis were measured by QCA. The correlation between exercise time ischaemia burden and QCA findings were assessed by linear regression with correction for clinically important variables which may influence exercise time. <h3>Results</h3> Baseline patient demographics are summarised in table 1. Mean exercise time was 6 minutes 36 seconds [SD 2 minutes 51 seconds] and energy expenditure was 9.2 METs [SD 3.2 METS]. There were significant negative correlations between exercise time and both ischaemia burden assessed by CMR and number of vessels with significant coronary stenosis (figure 1). From CMR data ischaemia burden was also associated with exercise time β -0.20 (95% CI -0.29 to -0.10), even after correction for age, BMI and sex (p &lt; 0.001). From QCA data maximum coronary stenosis β -0.014 (95% CI -0.020 to -0.0082) and cumulative coronary stenosis β -0.0043 (95% CI -0.0063 to -0.0024) are both associated with exercise time, even after correction for age, BMI and sex (p &lt; 0.0001). <h3>Discussion</h3> Exercise capacity is a strong prognostic indicator in patients with coronary artery disease. This study demonstrates that progressive coronary artery disease reflected by increased ischaemic burden on CMR and QCA is associated with reduced exercise capacity. However, whether reducing ischaemia burden by revascularisation leads to objective improvements in exercise capacity remains an ongoing area of debate. <h3>Conclusion</h3> The severity of coronary artery disease reflected by ischaemic burden on CMR and coronary stenosis by QCA is associated with exercise capacity in patients with stable angina. <h3>References</h3> Al-Lamee R, Thompson D, Dehbi HM, Sen S, Tang K, Davies J, <i>et al</i>. Percutaneous coronary intervention in stable angina (ORBITA): a double-blind, randomised controlled trial. <i>Lancet</i>. 2018;<b>391</b>(10115):31–40. Greenwood JP, Maredia N, Younger JF, Brown JM, Nixon J, Everett CC, <i>et al</i>. Cardiovascular magnetic resonance and single-photon emission computed topography for diagnosis of coronary heart disease (CE-MARC): a prospective trial. <i>Lancet</i> 2012;<b>379</b>(9814):453–460. Swoboda PP, Matthews GDK, Garg P, Plein S, Greenwood JP. Comparison of stress-rest and stress-LGE analysis strategy in patients undergoing stress perfusion cardiovascular magnetic resonance. <i>Circ Cardiovasc Imaging</i> 2023;<b>16</b>(12):e014765.