Asrar Ahmed

Relative clinical and economic impact of exercise echocardiography vs. exercise electrocardiography, as first line investigation in patients without known coronary artery disease and new stable angina: a randomized prospective study

Aims Exercise electrocardiography (ExECG) is widely used in suspected stable angina (SA) as the initial test for the evaluation of coronary artery disease (CAD). We hypothesized that exercise stress echo (ESE) would be efficacious with cost advantage over ExECG when utilized as the initial test. Methods and results Consecutive patients with suspected SA, without known CAD were randomized into ExECG or ESE. Patients with positive tests were offered coronary angiography (CA) and with inconclusive tests were referred for further investigations. All patients were followed-up for cardiac events (death, myocardial infarction, and unplanned revascularization). Cost to diagnosis of CAD was calculated by adding the cost of all investigations, up to and including CA. In the 194 and 191 patients in the ExECG vs. ESE groups, respectively, pre-test probability of CAD was similar (34 ± 23 vs. 35 ± 25%, P = 0.6). Results of ExECG were: 108 (55.7%) negative, 14 (7.2%) positive, 72 (37.1%) inconclusive and of ESE were 181 (94.8%) negative, 9 (4.7%) positive, 1 (0.5%) inconclusive, respectively. Patients with obstructive CAD following positive ESE vs. Ex ECG were 9/9 vs. 9/14, respectively (P = 0.04). Cost to diagnosis of CAD was £266 for ESE vs. £327 for ExECG (P = 0.005). Over a mean follow-up period of 21 ± 5 months, event rates were similar between the two groups. Conclusion In this first randomized study, ESE was more efficacious and demonstrated superior cost-saving, compared with ExECG when used as the initial investigation for the evaluation of CAD in patients with new-onset suspected SA without known CAD.

Relative diagnostic, prognostic and economic value of stress echocardiography versus exercise electrocardiography as initial investigation for the detection of coronary artery disease in patients with new onset suspected angina

Objectives We hypothesised that stress echocardiography (SE), may be superior to exercise ECG (ExECG), for predicting CAD and outcome, and cost-beneficial, when performed as initial investigation in newly suspected angina. Methods All patients seen in 2011, with suspected angina, no history of CAD, pre-test likelihood of CAD of > 10% and who underwent SE or ExECG as first line were identified retrospectively. Cost to diagnosis was calculated by adding the cost of all tests, up to and including coronary angiography (CA), on an intention-to-treat basis. Follow-up data on cardiac death and myocardial infarction (MI) were collected, 26 months after the presentation of the last study patient. Results A total of 456 patients underwent ExECG (224 (49%) negative, 93 (20%) positive, 139 (31%) inconclusive) and 241 underwent SE (200 (83%) negative, 35 (15%) positive, 6 (2%) inconclusive) as first line. In patients subsequently undergoing CA, CAD was present in 46% (37/80) of patients with positive ExECG vs. 72% (23/32) patients with positive SE (p = 0.01). Mean cost to diagnosis was £456 for the ExECG vs. £360 for the SE group (p = 0.002). Over a mean follow-up period of 31 ± 5 months, cardiac events were 2% each in negative SE vs. negative ExECG (p = 0.9). Conclusions SE is superior to ExECG for prediction of CAD and is cost-beneficial when used as initial test in patients with no history of CAD presenting with suspected angina.

The Benefits of Revascularization in Chronic Heart Failure

Recent efforts have reduced the mortality from coronary artery disease (CAD), with the consequent increase in heart failure with reduced left ventricular function, referred to as ischaemic cardiomyopathy (ICM). As ischemic left ventricular (LV) dysfunction may be partially or completely reversible by revascularization in the presence of viable myocardium, the assessment of myocardial viability is central to the management of ICM. Decades of observational analyses have provided positive evidence for the role of revascularization in hibernating myocardium in improving survival. However, recently the Surgical Treatment for Ischaemic Heart Failure (STICH) trial has challenged this notion, highlighting the noninferiority of optimal medical therapy (OMT) over revascularization and OMT. In this review, we discuss noninvasive imaging modalities to assess myocardial viability and the impact of myocardial viability on revascularization. We critically appraise the STICH trial and suggest an algorithm for viability testing before revascularization in patients with ICM and significant LV dysfunction.

The clinical efficacy and long-term prognostic value of stress echocardiography in octogenarians

Introduction Although stress echocardiography (SE) is invaluable in younger populations, its prognostic value may be attenuated in the elderly due to shorter life expectancy and the frequent presence of severe comorbidities. This study sought to evaluate the clinical effectiveness of SE in octogenarians, particularly its prognostic value over clinical variables, in predicting hard events. Methods A total of 374 consecutive octogenarians who underwent SE for evaluation of coronary artery disease (CAD) were assessed for feasibility, diagnostic accuracy and safety of the test, and followed up for hard outcomes (all-cause mortality, cardiovascular (CV) deaths and non-fatal myocardial infarction (NFMI)). Cox regression analysis was performed to identify predictors of outcome. Results Of the 374 tests, 360 (96.3%) were diagnostic. Of the 50 patients with inducible ischaemia, 33 patients (66%) proceeded to angiography of which 27 (82%) patients had significant CAD. During long-term follow-up of 4.0±2.0 years, there were 127 deaths and 36 NFMIs. The annualised mortality, NFMI and combined mortality /NFMI rates were 8.1%, 1.8% and 9.4% for patients with a normal SE and 12.1%, 5.5% and 14.1% for those with an abnormal SE, respectively. Predictors of NFMI on multivariate analysis were prior CAD (HR 2.89, CI 1.03 to 8.15, p=0.045), peripheral vascular disease (HR 3.33, CI 1.18 to 9.45, p=0.02), and inducible ischaemia (HR 3.97, CI 1.49 to 10.55, p=0.006). In patients without prior history of CAD, inducible ischaemia was the only independent predictor of NFMI (HR 8.72, CI 1.46 to 52.2, p=0.018). The larger the extent of ischaemia, the greater the incidence of NFMI. The independent predictors of CV events (NFMI or CV mortality) were PAD (HR 2.81, CI 1.21 to 6.52, p=0.016) and peak wall motion score index (HR 5.71, CI 1.67 to 19.6, p=0.006). Although inducible ischaemia predicted all-cause mortality on unadjusted analysis, it did not on multivariate analysis. Conclusions In octogenarians, SE demonstrated excellent feasibility, safety and diagnostic accuracy. SE parameters were independent predictors of NFMI and CV events, and the presence of inducible ischaemia was associated with a 50% increase in all-cause mortality.

Cost-effectiveness of a management strategy based on exercise echocardiography versus exercise electrocardiography in patients presenting with suspected angina during long term follow up: A randomized study

INTRODUCTION Exercise ECG (Ex-ECG) is advocated by guidelines for patients with low - intermediate probability of coronary artery disease (CAD). However, there are no randomized studies comparing Ex-ECG with exercise stress echocardiography (ESE) evaluating long term cost-effectiveness of each management strategy. METHODS Accordingly, 385 patients with no prior CAD and low-intermediate probability of CAD (mean pre-test probability 34%), were randomized to undergo either Ex-ECG (194 patients) or ESE (191 patients). The primary endpoint was clinical effectiveness defined as the positive predictive value (PPV) for the detection of CAD of each test. Cost-effectiveness was derived using the cumulative costs incurred by each diagnostic strategy during a mean of follow up of 3.0 years. RESULTS The PPV of ESE and Ex-ECG were 100% and 64% (p = 0.04) respectively for the detection of CAD. There were fewer clinic (31 vs 59, p < 0.01) and emergency visits (14 vs 30, p = 0.01) and lower number of hospital bed days (8 vs 29, p < 0.01) in the ESE arm, with fewer patients undergoing coronary angiography (13.4% vs 6.3%, p = 0.02). The overall cumulative mean costs per patient were £796 for Ex-ECG and £631 for ESE respectively (p = 0.04) equating to a >20% reduction in cost with an ESE strategy with no difference in the combined end-point of death, myocardial infarction, unplanned revascularization and hospitalization for chest pain between ESE and Ex-ECG (3.2% vs 3.7%, p = 0.38). CONCLUSION In patients with low to intermediate pretest probability of CAD and suspected angina, an ESE management strategy is cost-effective when compared with Ex-ECG during long term follow up.

115 Diagnostic concordance and clinical outcomes in patients undergoing fractional flow reserve and stress echocardiography for the assessment of coronary stenosis of intermediate severity

Introduction The ischaemic consequences of a coronary artery stenosis can be assessed by invasive fractional flow reserve (FFR) or by non-invasive imaging. We sought to determine (i) the concordance between wall thickening assessment and FFR during clinically indicated stress echocardiography (SE) and FFR measurements and (ii) the predictors of hard events in these patients. Methods and Results 194 patients who underwent SE and invasive FFR measurements in close succession were analysed for diagnostic concordance and clinical outcomes. At the vessel level, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of SE for identifying significant disease as assessed by FFR was 70%, 78%, 46% and 91% respectively. In patients with single vessel disease, the sensitivity, specificity, PPV and NPV were 86%, 66%, 38% and 95% respectively. The greatest discordance was seen in patients with wall thickening abnormalities (WTA) and negative FFR. During a follow up of 3.0±1.9 years there were 15 cardiovascular (CV) events. The number of wall segments with inducible WTAs emerged as the only independent predictor of CV events (HR 1.22 (1.05–1.43), p=0.01). FFR was not a predictor of outcome. There was a significant increase in event rate in patients with WTA/negative FFR and WTA/positive FFR, compared to patients with no WTA (p=0.04). However, no significant difference was seen between patients with WTA/negative FFR versus WTA/positive FFR (p=0.38) Conclusion In a patient population with significant CV risk factors, a normal SE effectively ruled out abnormal FFR. The greatest discordance was seen in patients with abnormal SE/normal FFR. In this group, patients had similar outcomes compared to those with abnormal SE/positive FFR but worse outcomes compared to patients with a normal SE. These findings have significant clinical implications.Abstract 115 Figure 1Abstract 115 Figure 2

145 Stress Echocardiography Demonstrates Excellent Feasibility, Safety and Diagnostic Accuracy in Patients with Significant Obesity: First Results from the Stress Ultrasonography in Morbid Obesity (SUMO) Study

Background Significant obesity is an increasing global health problem. Obese individuals often have a clustering of cardiovascular risk factors such as hypertension, diabetes and dyslipidaemia. Thus, symptomatic patients often have a high pre-test probability of coronary artery disease (CAD) and are frequently referred for cardiac stress testing. These patients can provide significant technical challenges for imaging due to body habitus. The feasibility, safety and accuracy of stress echocardiography in patients with morbid obesity is unknown. Methods In this prospective multi-centre study, height, weight, body mass index (BMI) and body surface area (BSA) of all patients clinically referred for SE were measured. For patients with BMI >35, patient demographics and SE test results were also collected. The feasibility of SE was defined as the ability to perform and complete the test, achieving interpretable images for all three coronary artery territories. Agreement with angiography findings in patients subsequently referred for cardiac catheterization was also evaluated. Results Over an 11 month period across 3 hospitals, 2601 patients underwent SE, by 12 different operators, of whom 170 (6.5%) had BMI >35. Mean age was 59yrs, 44% were male and 25% had known CAD. Mean BMI was 39.5 and mean BSA was 2.2 m2. Dobutamine and exercise stress were performed in 60% and 40% respectively. Ultrasound contrast was used in 96% cases. There were no complications during the SE studies. SE demonstrated excellent feasibility, with a diagnostic test result achieved in 163/170 (96%) patients. Of the 7 patients with inconclusive SE, 2 were due to side-effects from dobutamine, 2 due to failure to reach target heart rate and 3 were due to poor image quality (thus just 3/170 [2%] due to poor image quality). Of 23 patients with inducible ischaemia, 19 proceeded to angiography and 17 had corresponding significant CAD (positive predictive value 89%). Conclusions SE demonstrates excellent feasibility, safety and positive predictive value in real-world clinical practice in patients with morbid obesity. These results are clinically pertinent given the increasing proportion of such patients sent for non-invasive testing. Follow-up of this cohort to delineate event-free survival will reveal the accuracy of risk stratification of SE in this high-risk population.