453 Can We Predict Normal Further Testing After EST? A Retrospective Review

Abstract

Exercise stress testing (EST) is recommended for low-intermediate risk chest pain on emergency department discharge [[1]Cullen L, Greenslade J, Hawkins T, Hammet C, OI’Kane S, Ryan K et al. Improved Assessment of Chest painTrial (IMPACT): assessing patients with possible acute coronary syndromes. Med J Aust. 2017 Sept; 207(5): 195-200.Google Scholar]. 10-20% of ESTs result in further testing [2Greenslade J, Parsonage W, Ho A, Scott A, Dalton E, Hammet A et al. Utility of Routine Exercise stress testing among Intermediate Risk Chest Pain Patients Attending an Emergency Department. Heart Lung Circ. 2015 Sep;24(9):879-884.Google Scholar, 3Hermann L, Newman D, Pleasant A, Rojanasarntikul D, Lakoff D, Goldberg S et al. Yield of Routine Provocative Cardiac Testing Among Patients in an Emergency Department-Based Chest Pain Unit. JAMA Intern Med. 2013 June;173(12):1128-1133Google Scholar, 4Mudrick D, Cowper P, Shah B, Patel M, Jensen N, Petersen E. Downstream procedures and outcvomes after stress testing for chest pain without known coronary artery disease in the United States. Am Heart J. 2012 Mar:163(3):454-461.Google Scholar] causing resource consumption with limited data regarding predictors of negative downstream testing [[5]Christman M, Bittencourt M, Hulten E, Saksena E, Hainer J, Skali H. The Yield of Downstream Tests after Exercise Treadmill Testing: A Prospective Cohort Study. J Am Coll Cardiol. 2014 April: 63(13):1264-1274Google Scholar]. Define testing post EST and identify predictors of negative further testing. We performed a retrospective single-centre study of 693 ESTs over 18 months. 91 patients underwent further testing. Indications were electrically / symptomatically positive (n=12) Can we predict normal further, electrically positive / symptomatically negative (n=32), symptomatically positive / electrically negative (n=23), uninterpretable (n=2), sub-maximal (n=11) or equivocal (n=11) ESTs. Downstream modalities included invasive coronary angiography (n=10), CTCA (n=34), ESE (n=30), MPS (n=16), and DSE (n=1). 9 patients were revascularised, 4 had obstructive CAD unsuitable for revascularisation. 1 patient with an equivocal EST was revascularized. No patients with uninterpretable, sub-maximal or isolated symptomatically positive EST had obstructive CAD. Cardiovascular risk factor burden was higher in revascularised patients (mean 2.3 vs 1.3, p<0.05). There was no difference in age (p=0.56), duration of EST (p=0.35) and workload (p=0.27) between those with vs without obstructive CAD. There was a trend towards female gender being associated with normal testing after electrically positive EST (p=0.06). Electrically/symptomatically positive EST was associated with obstructive CAD (n=6/12, 50%) more often than electrically positive/symptom negative EST (n=6/32, 18.75%, p<0.05). No patients referred for further investigation after isolated symptom positive EST or sub-maximal EST were diagnosed with obstructive CAD. Larger prospective studies may obviate routine further testing in these groups.