The influence of afterload on left ventricular contractility: 2D-strain and dyssynchrony in stress echocardiography

Funding Acknowledgements Type of funding sources: None. Background Hypertensive response to exercise (HRE) has negative prognostic value but its impact on the left ventricle (LV) contractility and on stress echocardiography (SE) results remains controversial. The global longitudinal strain (GLS) and LV dyssynchrony changes in response to afterload increase were shown even in patients with narrow QRS at rest, but not on exertion. Purpose We aimed to analyze the relation between the blood pressure (BP) during SE and LV GLS and dyssynchrony changes. Methods We performed exercise SE on treadmill in 96 patients without coronary artery stenosis (invasive or CT coronary angiography). Patients divided into two groups: HRE (n = 41) and normal response to exercise (NRE) (n = 55). We analyzed GLS and standard deviation of time between the onset of QRS and segmental longitudinal strain peaks (STE-TIME SD) using speckle tracking and 3d-ejection fraction (EF) at rest and on exertion. Results 2D-EF increase was higher in patients with NRE, but 3D-EF did not differ between groups. Wall motion abnormalities (WMA) on peak stress were detected more often in patients with HRE who had higher wall motion score index (WMSI). GLS on exertion and its increment were lower in HRE group (Fig. 1 - "Bull’s eye" diagrams of GLS at rest and on exertion in patient with NRE (upper panel) and HRE (lower panel)). Among dyssynchrony markers we revealed higher values of STE-TIME SD on exertion in HRE group (Table 1). Moreover the analysis showed positive correlations between BP level on exertion and peak GLS (r = 0.56, p < 0.0001), GLS increase (r = 0.54, p < 0.0001) and STE-TIME SD on exertion (r = 0.27, p < 0.02) Conclusions HRE is associated with less increment in GLS and 2D-EF on exertion. Besides LV dyssynchrony signs can appear in response to exaggerated afterload increase even in patients with narrow QRS complexes. Patients with HRE more often show stress-induced WMA and have greater WMSI on exertion in absence of coronary artery lesions, thus HRE can alter the specificity of the test in transient ischemia detection. Table 1 HRE NRE p Δ-2D ejection fraction 5.0 (4.0; 7.0) 10.0 (8.0; 12.5) <0.0000001 Δ-3D ejection fraction 8.25 (4.0; 8.25) 8.24 (8.15; 11.65) 0.09 Wall motion abnormalities on exertion 46.34% 1.8% <0.00001 Wall motion score index 1.0 (1.0; 1.18) 1.0 (1.0; 1.0) 0.00013 GLS on exertion -21.0 (-22.0; -19.0) -24.0 (-26.5; -23.0) <0.0000001 ΔGLS 0.0 (-1.0; 2.0) 4.0 (2.0; 6.0) <0.0000001 STE-TIME SD-IMPOST 42.0 (35.0; 53.0) 35.0 (27.5; 45.0) 0.012 Left ventricle systolic function and dyssynchrony in two groups. Abstract Figure 1.

Abstract 16032: Determinants of Exercise Capacity Assessed Using Combined Stress Echocardiography and Cardiopulmonary Exercise Testing in Patients Treated for Acute Myocardial Infarction

Introduction: Exercise capacity (EC) after acute myocardial infarction (AMI) influences prognosis, but the causes of its reduction are complex and not sufficiently studied. Methods: We prospectively enrolled consecutive patients who underwent percutaneous coronary intervention for their first AMI without residual coronary stenosis and with left ventricular ejection fraction (LVEF) > 40% more than 4 weeks after the AMI. We performed combined stress echocardiography and cardiopulmonary exercise testing (CPET-SE) using a semi-supine cycle ergometer to determine predictors of EC (peak oxygen uptake [VO 2 ]). Results: Among 81 patients (70% male, mean age 58 ± 11 years), 40% suffered AMI with ST-segment elevation (STEMI), and 60% non-STEMI, LVEF was 57 ± 7%; wall motion score index, 1.18 (IQR 1.06 - 1.31); peak VO 2 , 19.5 ± 5.4 mL/kg/min. Multivariate analysis ( Table ) revealed that parameters at peak exercise: heart rate (β = 0.17, p < 0.001), stroke volume (β = 0.09, p < 0.001), and arteriovenous oxygen difference (β = 93.51, p < 0.001) were independently positively correlated with peak VO 2 , with arteriovenous oxygen difference being its strongest contributor. At rest, left ventricular systolic and diastolic function parameters and the extent of myocardial scarring (wall motion score index) did not predict EC (p > 0.05). Conclusions: In patients treated for AMI with normal/mildly reduced LVEF, EC is associated with peak peripheral oxygen extraction as well as peak heart rate and peak stroke volume. CPET-SE is a useful tool to evaluate decreased fitness in this group.

The Coronary ARteriogenesis with combined Heparin and EXercise therapy in chronic refractory Angina (CARHEXA) trial: A double-blind, randomized, placebo-controlled stress echocardiographic study

Background Coronary collateral circulation exerts protective effects on myocardial ischaemia due to coronary artery disease and can be promoted by exercise with heparin co-administration. Whether this arteriogenetic effect is accompanied by functional improvement of left ventricle during stress and lessening of angina symptoms remains unknown. Aims To evaluate the anti-ischaemic efficacy of heparin plus exercise in coronary artery disease. Methods In a prospective, single-centre, randomized, double-blind study we recruited 32 ‘no-option’ patients (27 males; mean age 61 ± 8 years) with stable angina, exercise-induced ischaemia and coronary artery disease not suitable for revascularization. All underwent a two-week cycle of exercise (two exercise sessions per day, five days per week) and were randomized ( n = 16 per group) to intravenous placebo (0.9% saline) versus unfractionated heparin (5.000 IU intravenously), 10 min prior to exercise. We assessed Canadian Cardiovascular Society angina class, stress electrocardiogram and echo parameters (wall motion score index) and computed tomography angiography for collaterals. Results After two-week cycle, Canadian Cardiovascular Society class statistically decreased in both groups (heparin plus exercise group: 2.6 ± 0.7 to 1.9 ± 0.7, p < 0.001, exercise group: 2.4 ± 0.7 to 2.1 ± 0.9, p = 0.046). Only the heparin plus exercise group improved time-to-ST segment depression (before 270, 228–327 s vs. after 339, 280–360 s, p = 0.012) and wall motion score index (before 1.38 ± 0.25 vs. after 1.28 ± 0.18, p = 0.005). By multi-slice computed tomography angiography, collaterals improved in 12/15 (80%) in the heparin plus exercise group versus 2/16 (12.5%) in the exercise group ( p < 0.001). Conclusion A two-week, 10-test cycle of heparin plus exercise is better than exercise in improving angina class, myocardial ischaemia and collaterals by computed tomography angiography.

P1786 Impact of exercise on platelet activity in patients with significant ischemic mitral regurgitation qualified for cardiosurgery treatment

Purpose Platelet activity is believed to play an important role in patients (pts)after myocardial infarction (MI). This study sought to examine a change in platelet activity after 2D echocardiography semi-supine exercise test (ExE) in pts with at least moderate ischemic mitral regurgitation (IMR) qualified for cardiosurgical treatment - coronary artery bypass grafting alone (CABG) or CABG with mitral reconstruction (CABGmr). Methods We collected venous blood samples from 70 patients (M 41, 66 ± 9 years) with at least moderate IMR, 3-24 weeks after MI. Platelet activity was estimated with the use of rapid, point-of-care platelet analyzer as the time (in seconds) for flowing whole blood to occlude a collagen-epinephrine ring, with shorter closure times, indicating greater activity (CEPI-CT- for assessing the thromboxane A2 –dependent activation pathway). CEPI-CT was evaluated before (CEPI-CT rest) and 20 min after ExE (CEPI-CT ExE). All the patients received 75-100 mg of aspirin daily (without clopidogrel treatment). Effective regurgitation orifice (ERO) was used for quantitative IMR assessment (moderate ≥10-20, severe ≥ 20 mm²). All the pts were referred for CABG (multivessel coronary disease, ejection fraction (EF) 42,6 ± 10,1%, wall motion score index (WMSI) 1.65 ± 0.36). Results We observed a significant decrease in CEPI–CT’s in all analyzed group (rest vs exe: 202 sec vs 124 sec, respectively; p &lt; 0,0001) and in pts with moderate IMR as well as in pts with severe IMR, despite aspirin treatment. The results of the analysis of CEPI-CT and IMR size at rest and after ExE in both groups of pts are shown in Table 1. A negative correlation was found between CEPI-CT ExE and ERO ExE (r=-0,752, p = 0,0042). Conclusions 1. Significant increase in platelet activity after exercise was observed in patients after MI with IMR qualified for cardiosurgical treatment. 2. The increase in platelet activity after exercise is correlated with exercise changes of IMR size. 3. Aspirin may have a limited antithrombotic effect after physical exercise in patients after MI with significant IMR. Table 1. CEPI-CT rest CEPI-CT ExE p ERO rest ERO exe p All 202 124 &lt; 0,0001 17 22 &lt;0,001 Moderate IMR 201 124 0,0001 15 20 &lt; 0,0001 Severe IMR 235,5 123,5 &lt; 0,0001 25 31 &lt; 0,0001

P1509The novel application of speckle tracking during dobutamine stress echo for assessment of coronary artery diseases

Background Major cause of death across the world is coronary artery disease. The choice of treatment strategy should be primarily based on the hemodynamic significance of coronary artery stenosis. Two-dimensional speckle tracking provides valuable information for regional wall motion abnormalities. The purpose of this study was to determine the diagnostic value of left ventricular longitudinal strain and torsion to diagnose coronary artery disease during dobutamine stress echocardiography. Purpose The purpose of this study was to evaluate the diagnostic value of speckle tracking imaging-derived myocardial deformation parameters at rest and during dobutamine stress to determine the hemodynamic significance of coronary artery stenosis in patients with moderate and high probability of CAD. Methods We studied 204 patients (mean age 54.2±9.8 years, 128 male and 76 female) with known or suspected coronary artery disease, excluding those with prior history of transmural infarction. All of them underwent dobutamine stress echo and coronary angiography within one month. Wall-motion score index, left ventricular global longitudinal strain and torsion were measured at rest and peak stress. Optimal cut-offs were derived from receiver operating characteristic curves for strain and torsion values. Additionally, the respective differences between rest and stress were also calculated. Results During dobutamine stress echocardiography we revealed mean left ventricular ejection fraction was 53±6.2%. Coronary angiography revealed significant stenotic lesions in 124 patients (60.7%). Values regarding sensitivity, and specificity for wall motion score index difference were 76% and 84% respectively (area under curve 0.84). Global longitudinal strain difference (median 0.6%) illustrated 83% sensitivity and 74% specificity for disease detection (area under curve 0.82, cut-off value ≤0.5%). The respective values for torsion difference (median 5.1°) were 84% and 79% (area under curve 0.80, cut-off value ≤5.9°). Combination of wall motion score index difference and torsion difference for disease detection showed 89% sensitivity and 77% specificity (area under curve 0.84). Conclusions Left ventricular strain and strain rate analyses during DSE can be used in the assessment of hemodynamic significance of coronary artery stenosis in patients with moderate and high risk for CAD. The implementation of speckle tracking during dobutamine stress echo could serve as an adjunct method for coronary artery disease assessment, providing quantitative diagnostic information.