Merli, Elisa

Abstract Introduction Transthoracic echocardiography (TTE) identifies a hypercontractile phenotype (HP) in chronic coronary syndromes (CCS), characterized by elevated resting left ventricular (LV) elastance (force = systolic blood pressure/end-systolic volume). To evaluate the prognostic significance and functional correlates of HP. Methods In a prospective multicentre study, 10 677 patients with CCS underwent resting TTE to assess LV ejection fraction (EF), stroke volume, and force by quantitative volumetric echocardiography. All patients were followed for the endpoint of all-cause mortality. In a subset of 5834 patients, stress echocardiography (exercise or dobutamine) was performed for LV contractile reserve and heart rate reserve. Results Patients were stratified into Force quintiles (Q1–Q5). Patients with hypercontractile phenotype exhibited lower stroke volume at rest (Q5 = 34.8 ± 12.3 vs Q1–Q4 = 57.4 ± 19.1 mL; P < .01) and higher EF at rest (Q5 = 64.8 ± 6.9% vs Q1–Q4 = 58.1 ± 8.7%, P < .01). During a median follow-up of 24 months (interquartile range = 12–40 months), 509 deaths occurred. The exposure-adjusted death rate was lowest in Q3 (3.53–4.51 mmHg/mL; 1.03 per 100 person/years) and higher in Q1 (≤2.62 mmHg/mL, 2.88), Q2 (2.63–3.52 mmHg/mL, 1.86), Q4 (4.52–6.11 mmHg/mL, 1.56), and Q5 (HP, >6.11 mmHg/mL; 1.88; P < .0001 vs Q1 and Q3). Multivariable analysis identified HP (Q5; HR 1.531 vs Q3, 95% CI 1.116–2.099; P = .006) and EF (HR 0.963, 95% CI 0.953–0.972; P < .0001) as independent predictors of death. During exercise or dobutamine stress, HP showed reduced LV contractile reserve (ΔEF: Q5 = 4.3 ± 9.4% vs Q1–Q4 = 7.0 ± 9.3%; P < .001) and blunted heart rate reserve (Q5 = 1.77 ± 0.33 vs Q1–Q4 = 1.85 ± 0.39; P < .01). All patients with force-based LV contractile reserve >4.1 (present in 185, 3.2% of the population) survived. Conclusion Patients with CCS with HP assessed by resting TTE demonstrate higher mortality and multilayered functional impairment, including reduced LV contractile and chronotropic reserves. Hypercontractile phenotype improved the prediction of mortality by EF. A ‘stronger’ heart is, in fact, functionally and prognostically weaker.

Abstract Background Exercise stress echocardiography (ESE) is recommended in patients with mitral regurgitation (MR) when resting echocardiographic findings and symptoms do not align. However, the role of MR assessment in patients undergoing ESE for any indication remains uncertain. Purpose This study aimed to investigate whether the assessment of MR during ESE provides prognostic value beyond the evaluation of inducible regional wall motion abnormalities (RWMA) in patients undergoing ESE for any clinical indication, including suspected coronary artery disease (CAD). Methods Data were analyzed from a large multicenter and multinational prospective study. Current analysis included patients who underwent ESE for any indication and had MR (from 0= absent, to 3= severe) assessed at rest and peak exercise with an integrated qualitative, semi-quantitative, and (in selected cases) quantitative assessment. The primary endpoint was all-cause mortality. Results Of 1,351 included patients (age 56±16 years; 66% women; 30% with known CAD). MR score increased during exercise (rest=0.74±0.7 vs. peak=0.89±0.8, p<0.001), with severe MR present in 2% of patients at rest and 7% at peak ESE. Patients with severe MR during exercise (n=96, Group 1) compared to those with non-severe MR during exercise (n=1255, Group 2) showed more B-lines, lower left ventricular contractile and chronotropic reserve, and trend (p=0.09) to more frequent decrease in ejection fraction during ESE (Table 1). After a median follow-up of 2.1 years (IQR 1.0–6.9), 99 patients (7%) had died. Severe MR at rest was associated with increased mortality (log-rank p<0.001). Patients with severe MR at peak ESE had a higher risk of death compared to the other patients (log-rank p 0.035) (Figure 1). After adjusting for age, CAD, and inducible RWMA, severe MR with exercise remained strongly associated with an increased risk of death (adjusted-HR: 2.2, 95%CI 1.3-3.8, p=0.002). Similar results were seen with further adjustment for rest MR severity (adjusted-HR:1.9, 95%CI 1.02-3.5, p=0.004). Conclusion Patients, with and without CAD, with severe MR during ESE have greater functional impairment expressed by more pulmonary congestion, blunted heart rate reserve, and lower left ventricular contractile reserve. The assessment of MR during ESE provides significant prognostic information, independent of resting RWMA or inducible ischemia. Incorporating MR evaluation into routine ESE protocols may improve clinical decision-making and patient outcomes.Fig 1 Survival by MR at peak exercise Table 1

Abstract Background Obese patients often exhibit a clustering of cardiovascular risk factors and are frequently referred for noninvasive cardiac imaging. Coronary microvascular dysfunction (CMD) represents an early indicator of cardiovascular disease that can be noninvasively diagnosed using coronary flow velocity reserve (CFVR) measurements obtained during stress echocardiography (SE) in patients without evidence of obstructive coronary artery disease (CAD). Purpose This study aimed to evaluate the prognostic significance of CFVR in overweight and obese patients within a prospective multicenter cohort. Methods 2273 patients (mean age 65 ± 11 years; 51% women) classified as overweight or obese (for definition see Table) were included in 27 sites from 11 countries. All patients had normal left ventricular ejection fraction (EF ≥ 50%), no prior history of CAD, and underwent exercise or pharmacological SE, which was negative for inducible ischemia. CFVR of the left anterior descending coronary artery was assessed, with CMD defined as CFVR >2.0. Patients were divided into two groups based on the presence (Group 1) or absence (Group 2) of CMD. The primary endpoint was overall mortality. Results CMD was identified in 492 patients (22%), with a mean CFVR of 2.3 ± 0.5 across the study population. Group 1 patients (CMD) were older, with a greater prevalence of diabetes and metabolic syndrome compared to group 2 (no CMD) (Table). During a median follow-up period of 2.1 years (IQR: 1.2-3.7 years), 103 patients (5%) died. Patients with CMD had significantly worse late survival compared to those without CMD (3-year survival: 96 ± 1% vs. 96 ± 1%, p=ns; 6-year survival: 79 ± 4% vs. 93 ± 1%, p < 0.0001): see Figure. Multivariate analysis adjusting for age, sex, EF, body mass index, smoking habits, diabetes, dyslipidemia, arterial hypertension, and type of stress confirmed CMD as an independent predictor of mortality (hazard ratio: 1.8 [95% CI: 1.1–2.8], p = 0.01). Conclusions CMD, assessed via CFVR during SE, was a robust and independent prognostic marker of long-term mortality in obese patients with preserved EF and no evidence of inducible ischemia. These findings underscore the pivotal role of noninvasive assessment of CMD in refining risk stratification and guiding clinical decision-making in this high-risk population.

Abstract Aims Chronotropic incompetence (CI) is a biomarker of cardiac autonomic dysfunction. The aim of the study is to assess the risk stratification value of CI during exercise or pharmacological stress echocardiography in patients with chronic coronary syndromes. Methods and results In a prospective, multicenter, international, observational study, we enrolled 13 445 patients with known or suspected chronic coronary syndromes who underwent stress echocardiography in 19 clinical sites from 10 countries using either exercise (n = 2594), dobutamine (n = 2440), or dipyridamole (n = 8411). Heart rate was automatically measured from the 1-lead ECG in the echocardiography monitor. We considered CI as failure to reach 85% of the maximal predicted (220-age) heart rate for exercise and dobutamine, and heart rate reserve (peak/rest heart rate) ≤ 1.22 (≤1.17 if in permanent atrial fibrillation) for dipyridamole stress. The primary outcome was all-cause death. CI was observed in 5045 patients (38%) and stress-induced regional wall motion abnormalities in 1648 (13%). Over a median follow-up time of 3.4 years (interquartile range, 1.6–9.1 years), there were 2426 (18%) deaths. The 10-year mortality was 39% in patients with and 21% in patients without CI (P < 0.0001). CI was associated with a significant increase in 10-year mortality in all age groups ranging from ≤54 years to ≥75 years (P < 0.0001). In addition, it was associated with increased mortality (P < 0.0001) irrespective of β-blocker use. Cox multivariable analysis revealed that CI was an independent predictor of mortality (HR: 1.60, 95% confidence interval: 1.47–1.74; P < 0.0001) together with age, male sex, diabetes mellitus, left ventricular ejection fraction, and resting heart rate. Conclusion In patients with chronic coronary syndromes, CI during exercise or pharmacological stress is a simple and objective predictor of survival.

Over the past decade, stress echocardiography has evolved from a test for assessing epicardial artery stenosis to a comprehensive functional test, targeting multiple cardiovascular parameters. The new approach includes several structured steps: (a) evaluating regional wall motion abnormalities to detect epicardial artery stenosis or vasospasm; (b) assessing pulmonary congestion and diastolic function via B-lines with lung ultrasound; (c) gauging preload and contractile reserve with volumetric echocardiography; (d) measuring coronary microvascular reserve using Doppler-based coronary flow velocity in the middistal left anterior descending artery; and (e) determining cardiac sympathetic reserve by tracking heart rate reserve on an ECG. This evolution was supported extensively by the Italian Society of Echocardiography and Cardiovascular Imaging (SIECVI), which played a key role in five areas: (1) developing the initial, curiosity-driven project; (2) disseminating protocols and results at national and international conferences, supporting logistic infrastructure and publication expenses; (3) establishing a digital platform (customized Redcap) for data entry and storage; (4) facilitating patient recruitment across 19 Italian centers; and (5) offering formal endorsement through six presidencies, adding credibility and reach beyond any single institution. The protocol quickly advanced from concept to high-impact publications, earning inclusion in 2024 specialty guidelines. Initially Italian-led, the study now includes 50 centers across 20 countries (e.g. USA and China). Beyond the 50 peer-reviewed papers published in 2016–2024, this study offers a novel, sustainable approach to cardiac stress testing, providing more information at lower costs, with zero radiation and minimal environmental impact. SIECVI’s endorsement was instrumental in amplifying the study’s rigor and outreach.

Abstract Background Atrial fibrillation (AF) is the most prevalent atrial tachyarrhythmia, affecting an estimated 2-4% of adults worldwide. AF is a well-recognized and treatable risk factor for stroke, but it often remains asymptomatic or subclinical, leading to underdiagnosis. This study aimed to identify distinguishing signs during exercise stress echocardiography (ESE) among patients in sinus rhythm (SR), with and without history of paroxysmal/persistent AF (PAF). Methods An international prospective cohort comprising 1035 consecutive patients was initially considered from 12 cardiology institutions. These patients were referred for clinically-driven ESE as part of the Stress Echo 2020-2030 study network. All patients underwent comprehensive ESE with the ABCDE protocol, which included assessment of B-lines, left ventricle contractile reserve (LVCR), ECG-based heart rate reserve (HRR), LV ejection fraction (EF), LV end-diastolic volume, E/e’, pulmonary artery systolic pressure estimation, tricuspid annular plane sytolic excursion (TAPSE), left atrium volume index (LAVi) and left atrium reservoir phase strain (LASr) at rest and with exercise. Results After excluding 89 patients who were in AF during the ESE, 946 patients in SR were included as the main study cohort (101 with and 845 without a history of PAF). A scoring system was then constructed using all independent variables that differentiate the two groups (those with and without history of PAF). Presence of systemic hypertension, rest LAVI>31ml/m2, rest |LASr|< 21%, stress LAVI >29 ml/m2, stress |LASr| <24%, stress E/e’ >7, ∆TAPSE <4.5 mm, HRR<1.87, and LVCR<1.6 were identified as the discriminators between patients with and without PAF. The composite score, summing all 9 items (with a total score range from 0 to 9), yielded a score of >4 as the best balance between sensitivity (87%) and specificity (60%) in predicting those with PAF. The receiver operating characteristic curve analysis of the scoring model showed an AUC of 0.79 (p-value <0.0001), Figure. Conclusion ESE evaluation can be a valuable adjunct for identifying patients in SR with history of PAF. This multifaceted approach enhances the potential for more accurate detection and clinical management of individuals in SR at risk for AF, who could be considered for aggressive monitoring programs to prevent the development of new onset AF and subsequent increase in cardiovascular risk.

Abstract Background Guidelines recognize the role of exercise stress testing in evaluating functional capacity in patients with asymptomatic severe aortic stenosis (AS). The study aimed to identify the prognostic role of exercise stress echocardiography (ESE) in asymptomatic severe AS. Methods We enrolled 153 asymptomatic patients (70±13 years; 88 male, 57%) with severe AS, aortic valve area (AVA) <1.0 cm2, mean aortic gradient ≥ 40 mmHg, ejection fraction (EF) ≥55%. All were referred for ESE in 7 quality-controlled centers from 5 countries. Rest and ESE assessment also included global longitudinal strain (GLS) and left atrial volume index (LAVI). B-lines were assessed by LUS with the 4-site simplified scan of the third intercostal space. A 4-point ESE score was based on 4 parameters (0 for normal, 1 for abnormal), with the following pre-determined cutoffs of abnormality: ∆-maximal aortic gradient (MAG) ≥20 mmHg; GLS at peak ≤ 19%, according to receiver operating characteristics curve analysis, stress B-lines ≥2; stress LAVI ≥ 34 mL/m2. Follow-up was completed in 142/153 patients (92%). Results At rest, AVA was 0.85±0.14 cm2, maximal aortic gradient: 79±14 mmHg, and peak aortic velocity: 4.42 ± 0.41 m/s. Mean EF at rest: 63.4±5.3% During a median follow-up of 1802 days (IQ range 651-2302), 41 events occurred in 39 patients: 15 all-cause deaths, 17 acute HF, 1 stroke, 1 myocardial infarction, and 7 coronary revascularization. Patients experiencing events displayed a greater increase in MAG during peak ESE, more B-lines with exercise, greater degree of LAVI dilation with exercise and slightly lower GLS compared to those without events (Table). Increase in ESE score was associated with a significant rise (p=0.001) in event incidence from score 0 (n=0/13, 0%) to score 1 (n=2/21, 9.5%), score 2 (n=10/42, 23.8%), and ≥3 (n=27/66, 40.9%), see figure. Conclusions In asymptomatic severe AS cases with preserved LV EF, comprehensive ESE provides early marker of potential cardiac decompensation at follow-up. The composite ESE index, including MAG, GLS, LAVI, and B-lines, holds promise as a prognostic predictor.TableFigure

Abstract Background Hypercontractile phenotype (HP) of the left ventricle (LV) is an actionable therapeutic target in patients with chronic coronary syndromes (CCS) or heart failure (HF), but its clinical recognition remains difficult. Objectives To assess the clinical variables associated with the HP. Methods In a prospective, observational, multicenter study, we recruited 5,122 patients (age 65 ± 11 years, 2974 males, 58%) with CCS and/or HF with preserved ejection fraction (EF). Systolic blood pressure (SBP) was measured. We assessed wall motion score index (WMSI), LV end-diastolic volume (EDV), end-systolic volume (ESV), EF, force (SBP/ESV), stroke volume (SV), arterial elastance (SBP/SV), and ventricular-arterial coupling (VAC, as SV/ESV). Univariable and multivariable logistic regression analysis assessed independent factors associated with the highest force sextile. Results For all the studied patients, force was 4.51 ± 2.11 mmHg/ml, with the highest sextile (Group 6) > 6.36 mmHg/ml. By multivariable logistic regression model, the highest sextile of force was associated with age > 65 years (OR 1.62, 95% CI 1.36–1.93, p < 0.001), hypertension (OR 1.76, 95% CI 1.40–2.21, p < 0.001), female sex (OR 4.52, 95% CI 3.77–5.42, p < 0.001), absence of beta-blocker therapy (OR 1.41, 95% CI 1.16–1.68), rest SBP ≥ 160 mmHg (OR 2.81, 95% CI 2.21–3.56, p < 0.001), high heart rate (OR 2.08, 95% CI 1.61–2.67, p < 0.001), and absence of prior myocardial infarction (OR 1.34, 95% CI 1.07–1.68, p = 0.012). Patients in the highest sextile of force showed lower values of WMSI, SV, EDV, and ESV, and higher values of arterial elastance and VAC. Conclusions HP of the LV with high force was clinically associated with advanced age, female sex, high resting SBP, and the absence of 𝛽-blocker therapy. By transthoracic echocardiography, HP was associated with a small heart with reduced EDV, reduced SV despite high EF, and higher arterial elastance.

Abstract Background Guidelines recognize the role of exercise stress testing in evaluating functional capacity in patients with asymptomatic severe aortic stenosis (AS). Exercise stress echocardiography (ESE) allows the detection of pulmonary congestion with B-lines by lung ultrasound (LUS). Aim To identify the prevalence, determinants, and functional correlates of B-lines during ESE in asymptomatic severe AS. Methods We enrolled 35 asymptomatic patients (age= 69±16 years, 69% male) with severe AS, aortic valve area (AVA) &lt;0.6 cm2/m2, mean aortic gradient (MAG) ≥ 40 mmHg, left ventricular ejection fraction ≥55%. All patients were referred for ESE (treadmill in 1, bicycle in 34 patients) in 7 experienced centers from 4 countries between 2021-2022. ESE assessment at rest and peak stress included global longitudinal strain (GLS), left atrial volume index (LAVI) and cardiac output (CO). B-lines were assessed by simplified LUS from 4 lung zones across the third intercostal space (2 on each side). Heart rate reserve (HRR) was measured as the peak/rest heart rate. CO reserve was calculated as the difference between peak stress CO and rest CO. Results B-lines (≥2) were present in 2 patients at rest and in 15 patients during ESE (6% vs 43%, p&lt;0.001). When compared to patients without B-lines during ESE (Group 1, n=20), patients with B-lines during ESE (Group 2, n=15) were older (Group 1= 64±18 vs Group 2=75±8 years, p=0.030) had larger LAVI, higher logNT-pro-BNP and a trend to higher systolic pulmonary artery pressures (SPAP), see Table. The 2 groups showed similar values of resting AVA (Group 1= 0.52±0.11 vs Group 2=0.47±0.15 cm2/m2, p=0.311), stress AVA (Group 1= 0.45±0.09 vs Group 2=0.49±0.13 cm2/m2, p=0.663), resting MAG (Group 1= 45±15 vs Group 2=46±10 mm Hg, p=0.491), and stress MAG (Group 1= 59±19 vs Group 2=58±11 mm Hg, p=0.665). Patients with B-lines during ESE showed lower HRR and CO reserve, with a trend towards lower peak GLS, see Table. Conclusions Exercise-induced pulmonary congestion as evidenced by development of sonographic B- lines on LUS were present commonly (43%) among patients with "asymptomatic" severe AS undergoing ESE. Patients with exercise-induced B-lines have larger resting LAVI, higher NT-pro-BNP levels, lower CO reserve, and blunted HRR. Exercise-induced B-lines might provide an early sign of cardiac decompensation in "asymptomatic" patients with severe AS, which is an important factor to consider in the decision to intervene.TableFigure