Sothinathan Gurunathan

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.

Prognostic usefulness of contemporary stress echocardiography in patients with left bundle branch block and impact of contrast use in improving prediction of outcome.

Aims Patients with symptomatic left bundle branch block (LBBB) may have myocardial ischaemia due to both coronary artery disease and/or cardiomyopathy (microcirculatory abnormalities) and may have concomitant left ventricular (LV) dysfunction. We aimed to assess the feasibility and prognostic value of contemporary stress echocardiography (SE), which can uncover both pathophysiologies in LBBB patients in routine clinical practice, and also aimed to assess the additive value of contrast SE. Methods and results Accordingly, 190 consecutive patients (age 70.5 ± 11.3 years, LV ejection fraction = 50.1 ± 10%) with symptomatic LBBB who underwent SE over 6 years were assessed, of which 142 (75%) underwent contrast SE and 176 (92.6%) had diagnostic SE. Inducible ischaemia was present in 25 (14.2%) patients. During follow-up (35.4 ± 20.2 months) there were 32 deaths (18%) and 18 (10.2%) first cardiovascular (CV) events (acute myocardial infarction/mortality) in the 176 patients with diagnostic studies. Wall thickening score index at peak stress (WTSIpeak), which measures combined LV function and inducible ischaemia, was an independent predictor of mortality (HR = 3.78, 95% CI = 1.39-10.31, P = 0.01) and CV events (HR = 3.96, 95% CI = 1.1-14.3, P = 0.036). An abnormal SE (myocardial ischaemia and/or abnormal LV function) predicted an almost three-fold increase in all-cause mortality and CV events compared with normal SE. Amongst the confounders affecting assessment of wall thickening in LBBB and conventional prognostic variables, use of contrast was an independent predictor (P = 0.034) of WTSI1.16 (optimal predictor of mortality/CV outcome). Conclusion SE in patients with LBBB demonstrated high feasibility and the combination of LV systolic function and myocardial ischaemia provided important prognostic information. Contrast-enhanced SE improved the prediction of outcome.

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.

Stress Echocardiography in Stable Coronary Artery Disease

Purpose of ReviewStress echocardiography (SE) is a well-established technique for the diagnosis and risk stratification of patients with known or suspected coronary artery disease (CAD). This review article summarizes the status of SE in CAD, including testing protocols, clinical efficacy and current use of newer technologies: myocardial perfusion, strain imaging, three-dimensional echocardiography and adjunctive carotid ultrasonography.Recent FindingsRecent major findings in SE include the clinical value of myocardial perfusion imaging in multicentre studies, as well as when added to left ventricular (LV) wall motion assessment in clinical service. Additionally, SE has been shown to be more cost-effective than exercise ECG in patients with low-intermediate pre-test probability of CAD. Adjunctive atherosclerosis imaging by carotid ultrasonography (CU) to ischaemia testing by SE provides synergistic prognostic value, equivalent to hybrid imaging by PET-CT.SummaryDespite the development of newer and more expensive imaging modalities, SE remains the cornerstone for the assessment of CAD and has excellent clinical efficacy, is safe and is cost-effective.

Long-Term Association of Dipyridamole Stress Myocardial Contrast Echocardiography versus Single-Photon Emission Computed Tomography with Clinical Outcomes in Patients with Known or Suspected Coronary Artery Disease

Background: Single‐photon emission computed tomography (SPECT) is a well‐established method to evaluate patients with coronary artery disease. Myocardial contrast echocardiography (MCE) is an imaging technique that allows the assessment of myocardial perfusion in real time. Previous research has shown that vasodilator MCE is superior to SPECT for the prediction of hard events. The aim of this study was to investigate the long‐term association of SPECT and MCE with clinical outcomes in patients with known or suspected coronary artery disease. Methods: Accordingly, 258 patients who underwent MCE and SPECT as part of multicenter studies performed prospectively were followed up for hard events (all‐cause mortality and nonfatal myocardial infarction). The mean age was 63.4 ± 5.5 years, 186 (72.1%) were men, and 32 (12.4%) had left ventricular systolic dysfunction. We calculated the ratio of the number of abnormal segments (at rest and/or stress) to the total number of segments expressed as MCE and SPECT indices. Results: Over a mean follow‐up period of 80.4 ± 6.1 months, 46 patients had hard events. MCE and SPECT indices were associated with all‐cause mortality on univariate analysis (P = .008 and P = .035, respectively) but only MCE index was independently associated with hard events (hazard ratio, 4.24; 95% CI, 1.27–14.15; P = .019), beyond clinical data and left ventricular function, and independently associated with hard cardiac events (hazard ratio, 4.78; 95% CI, 1.06–21.59; P = .042). Conclusions: MCE but not SPECT showed a long‐term association with outcome. These results thus favor the routine use of MCE in the long‐term assessment of patients with known or suspected coronary artery disease. HIGHLIGHTSMCE has better long‐term association with outcome than SPECT.MCE was associated with hard events independent of clinical prognostic markers.MCE was also independently associated with hard cardiac events.MCE, not SPECT, is associated with long‐term hard events in assessment of CAD.

124 Stroke volume determined flow reserve does not predict the true severity of low-flow low-gradient aortic stenosis and is not a robust marker of contractile reserve in patients undergoing low-dose dobutamine echocardiography

Background During low-dose dobutamine stress echocardiography (LDDSE) in low-flow low-gradient aortic stenosis (LFLGAS), both the aortic stenosis (AS) severity and the presence of contractile reserve (CR) are conventionally assessed based on stroke volume flow reserve (SVFR), which is defined as stroke volume [SV] increase 20%. However frequent exaggerated chronotropic response to dobutamine with shortening left ventricular time result in SV drop. On the contrary, transvalvular flow rate (FR) (SV/ejection time) and left ventricular ejection fraction (LVEF) may increase. We aimed to assess the value of FR 200 ml/s (normal FR) and LVEF change in the identification of true severe AS (TSAS) and the assessment of CR respectively. Methods Accordingly 74 consecutive patients (mean age 78 years) with LFLGAS referred for LDDSE for determination of AS severity and CR underwent retrospective assessment of SV, FR, LVEF and standard echocardiographic parameters of AS severity (Table 1). The outcome assessed was all-cause mortality censored for aortic valve intervention. Results SVFR was present in 30 (40.5%) of the 74 patients whereas FR 200 ml/s was achieved in 60 (81.1%) (p<0.001). During the median follow-up of 316.5 days 28 (37.8%) deaths occurred. Amongst all standard echocardiographic predictors of AS severity at peak stress (aortic valve mean and peak gradient, peak velocity and area [AVA]) and clinical prognostic factors, AVA was an independent predictor of death (HR=0.1, 95%CI=0.02–0.7, p=0.03), and was therefore used to define TSAS (stress AVA 1.01cm2). TSAS was present in 47 (63.5%) patients of whom SVFR correctly identified 17 (36.2%) compared to 34 (72.3%) with FR 200 ml/s (p=0.001). In the 48 patients with LVEF 50%, amongst SV, FR and LVEF changes, only the latter was an independent predictor of death (HR=0.92, 95% CI=0.87–0.98, p=0.02) (Table 2). LVEF change of <5% was the best cut-off for the prediction of death (log rank p=0.004) and therefore for determination of CR (Figures 1-2). Increase in LVEF 5% had a significant impact on survival both on patients that underwent aortic valve intervention (log rank p=0.03) and those who underwent medical management (log rank p=0.01), as opposed to presence of SVFR (log rank p=0.234 and p=0.708 respectively). Conclusions During LDDSE in LFLGAS normalised FR, not SVFR, is a better determinant of TSAS, whereas assessment of LVEF change instead of SVFR determines CR.Abstract 124 Table 1 Patient echocardiographic characteristics Rest Stress p HR (bpm) 74.9±14.5 97.5±18.7 <0.001 LVEF (%) 43±15.7 53.5±18.5 <0.001 AVA (cm2) 0.77±0.13 0.92±0.2 <0.001 AVMG (mmHg) 25.7±6.7 35.3±10.9 <0.001 AVVmax (cm/sec) 328.1±43.3 384.8±52.5 <0.001 SV (ml) 56.6±14.1 64.4±16 <0.001 SVi (ml/m2) 32.3±8.2 36.8±9.7 <0.001 Flow Rate (ml/sec) 179.8±34.6 240.1±55.4 <0.001Abstract 124 Table 2 Univariable and multivariable analysis for prediction of all-cause mortality in patients with LVEF 50% Univariable Multivariable HR 95% CI p value HR 95% CI p value Age 1.002 0.9–1.1 0.96 Hypertension 0.9 0.3–2.5 0.85 Diabetes 0.9 0.3–2.6 0.88 Presence of ischaemia on stress echo 2.68 0.59–12.14 0.20 Change SV (ml) 0.99 0.9–1.04 0.67 Change FR (ml/sec) 0.99 0.98–1.004 0.19 Change LVEF (%) 0.92 0.87–0.98 0.02 0.92 0.87–0.98 0.02Abstract 124 Figure 1Abstract 124 Figure 2