High resting coronary flow velocity predicts worse survival in chronic coronary syndromes

Background

Coronary flow velocity (CFV) in the mid-distal left anterior descending coronary artery (LAD) can be easily assessed with transthoracic echocardiography (TTE). Although high resting CFV is associated with a reduced coronary flow velocity reserve which is a predictor of poor outcome, the prognostic significance of resting CFV remains unknown.

Aim

To assess the relationship between resting CFV and outcome.

Methods

Out of 11,410 initially screened, we prospectively enrolled 10,023 patients (age 64±12 years, 5,902 men, left ventricular ejection fraction [LVEF] 58±10%) with chronic coronary syndromes referred for resting TTE and with interpretable CFV. Recruitment (years 2004–2020) involved 5 accredited laboratories, with inter-observer variability <10% for CFV at study entry. Baseline peak diastolic CFV was obtained by pulsed-wave Doppler in mid-distal LAD. All-cause death was the only end-point.

Results

The feasibility of CFV was 95%. The mean CFV of LAD was 32±14 cm/s. By multivariable logistic regression analysis diabetes mellitus, prior myocardial infarction, lower LVEF and higher age, heart rate, and systolic blood pressure were associated with the highest quintile of CFV. During a mean follow-up of 4.6±3.7 years, 1,066 died. Mortality at 10-years was lowest (15%) in patients in the lowest quintile (≤24 cm/s) and highest (34%) in patients in the highest (≥38 cm/s) quintile of CFV. Age (HR 1.057, 95% CI 1.053–1.062; p<0.0001), diabetes mellitus (HR 1.845, 95% CI 1.573–2.164; p<0.0001), prior coronary surgery (HR 1.350, 95% CI 1.064–1.712; p=0.01), LVEF (HR 0.973, 95% CI 0.963–0.982; p<0.0001), the 4th quintile (HR 1.267, 95% CI 1.010–1.589; p=0.04), and the 5th quintile of CFV of LAD (HR 1.311, 95% CI 1.040–1.652; p=0.02) independently predicted mortality. At incremental analysis, CFV of LAD added prognostic information to clinical findings and LVEF.

Conclusion

CFV imaging in mid-distal LAD is highly feasible with TTE. High resting CFV predicts worse survival in the long-term.

Funding Acknowledgement

Type of funding sources: None.

Supra-normal values of resting left ventricular systolic function are associated with decreased survival: to good to be normal?

Background

Hyper-contractile phenotype of the left ventricle (LV) is generally considered prognostically benign, but recent data challenge this intuitive assumption.

Aim

To assess the effects of resting LV function on survival.

Methods

In a prospective, observational, multicenter study, we recruited 5,122 patients (age 65±11.1 years, 2974 males, 58%) with chronic coronary syndromes referred for resting transthoracic echocardiography with technically successful volumetric echocardiography in 14 accredited laboratories. All recruiting centers had a structured follow-up program with >90% follow-up rate. In each patient, we quantitatively assessed (by Simpson's biplane, apical single-plane or parasternal linear method) LV end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF). As a load-independent index of LV contractility, LV force was estimated as systolic blood pressure by cuff sphygmomanometer/ESV. All-cause death was the only considered outcome end-point.

Results

EF was 59±11% (normal reference sextile = 58.0–59.9%). Force was 4.51±2.11 mmHg/ml (normal reference sextile = 3.50–4.27 mmHg/ml). The correlation between EF and force was linear (r=0.585, p<0.001). After a median follow-up of 862 days, there were 265 all-cause deaths. Considering EF values, mortality was lowest in the highest sextile (>67%) and significantly higher in the lowest sextile (EF <52%): see figure, left panel. A U-shaped curve was found with force, with mortality values being lowest in the middle sextile and significantly higher in the lowest sextile (<2.59 mmHg/ml) and in the highest sextile (>6.36 mmHg/ml): see figure, right panel. At multivariable analysis, after adjustment for age, diabetes, EF, and prior myocardial infarction, both the highest sextile of force (HR 1.84, 95%, confidence intervals 1.12–3.03 p=0.015), and the lowest sextile of force (HR 1.77, 95%, confidence intervals 1.08–2.90 p=0.024) were associated with decreased survival.

Conclusion

Sub-normal values of resting ejection fraction and super- and sub-normal values of the force are associated with worse survival in patients with chronic coronary syndromes. This U-shaped curve of mortality is detectable only with the force, a load independent index of LV contractility: too much of a good thing such as LV contractility can be dangerous on the long-run.

Funding Acknowledgement

Type of funding sources: None.

Left atrial volume, function and B-lines at rest and during vasodilator stress echocardiography

Background

Left atrial volume index (LAVi), left atrial reservoir function assessed with global peak amplitude longitudinal strain (PALS), and B-lines at lung ultrasound are supplementary markers of left ventricular filling pressures.

Aim

To assess the relationship between LAVi, PALS and B-lines at rest and peak vasodilator stress.

Methods

A comprehensive dipyridamole stress echo was completed in 266 patients (187 male, 71%, age 65±10 years) with chronic coronary syndromes. LAVi was measured with the biplane disk summation method. PALS was measured from a single vendor with 2-dimensional speckle tracking echocardiography and expressed in % values as the mean of the 12 atrial segments from 4- and 2-chamber values. B-lines were assessed with the simplified 4-site scan in the third intercostal space, with global score from 0 to 40, and considered significant with global score ≥2 units.

Results

During dipyridamole, LAVi decreased (rest= 26±14 ml/m2 vs stress= 24±12 ml/m2, p<0.001), PALS increased (rest= 33±8 vs stress= 38±10%, p<0.001), and B-lines were more frequent (rest= 0.4, median interquartile range 0–30, vs stress= 0.7, median interquartile range 0–30, units, p<0.001). There was a significant, linear, inverse correlation between LAVi and PALS both at rest (r=−0.301, p<0.001) and at peak stress (r=−0.279, p<0.001, see figure). At group analysis, peak B-lines were directly correlated with peak LAVi (r=0.151, p=0.017) and inversely correlated with peak PALS (r=−0.234, p<0.001). At individual patient analysis, 4/93 patients (4.3%) showed stress B-lines (black dots in figure) with normal LAVi (<34 ml/m2) and preserved PALS (>42%).

Conclusion

Vasodilator stress echocardiography with combined assessment of left atrial volume, function and pulmonary congestion is feasible with high success rate in patients with chronic coronary syndromes. Pulmonary congestion is more frequent with dilated left atrium with reduced atrial contractile reserve, but it may occur in a minority of patients with normal LAVi and normal PALS.

Funding Acknowledgement

Type of funding sources: None.

Heart rate reserve complements regional wall motion abnormality for predicting outcome in hypertensives during stress echocardiography

Background

Stress echocardiography (SE) was recently upgraded to include imaging-independent heart rate reserve (HRR) which assesses cardiac sympathetic balance and is simply based on one-lead electrocardiogram present in the echo monitor. The value of HRR for risk stratification of hypertensive patients remains undetermined.

Aim

To assess the prognostic value of SE with HRR in hypertensive patients in a prospective, large scale, multicenter, international, effectiveness study.

Methods

From July 2016 to December 2020, we enrolled 2747 hypertensives (age 66±10 years, 1599 males, 58.2%; ejection fraction 61±8%) referred from 12 certified laboratories. All patients underwent clinically indicated SE. The employed stress modality was exercise (n=754) or pharmacological stress (n=1993). Exercise modality was either semi-supine bike (n=674) or treadmill (n=80). Pharmacological stress was either vasodilator (n=1695, 1661 with dipyridamole and 34 with adenosine) or dobutamine (n=298). SE response included the evaluation of regional wall motion abnormality (RWMA) and non-imaging HRR (peak/rest heart rate), with stress-specific cutoff values abnormal response <1.80 for exercise or dobutamine, <1.22 for dipyridamole or adenosine. All-cause death was the only end-point.

Results

Rate of abnormal results was 17% for RWMA and 40% for HRR. During a median follow-up of 624 days (interquartile range: 380–1037 days), 60 deaths occurred. Global X2 was 25.0 considering clinical and resting echocardiographic variables, with no change after stress-induced RWMA and a significant increase after HRR (Figure 1). Annual mortality rate was 0.7% person/year for patients (n=1496) with normal HRR and absence of stress-induced RMWA, 0.4% for patients (n=151) with RWMA and normal HRR, up to 2.1% person/year for patients (n=1101) with abnormal HRR with (n=321) or without (n=780) RWMA. At multivariable analysis, only age (HR: 1.070, 95% CI: 1.039–1.101, p<0.001) and abnormal HRR 2.651 (HR: 2.651, 95% CI: 1.550–4.543, p<0.001) showed independent value in predicting survival.

Conclusion

SE with either exercise or pharmacological stress allows an effective prediction of survival in hypertensive patients with chronic coronary syndromes, but only when the conventional criterion of RWMA is complemented with imaging-independent HRR.

Funding Acknowledgement

Type of funding sources: None.

Machine-learning algorithms for prediction of survival by stress echocardiography in chronic coronary syndromes

Background

Stress echocardiography (SE) is based on regional wall motion abnormalities and coronary flow velocity reserve (CFVR). They recognise different and complementary pathophysiological targets, and show independent and incremental value in predicting survival [1]. The approach based on machine-learning (ML) has the recognised potential to identify unsuspected patterns, and this can be especially relevant in the field of risk stratification by cardiac functional stress testing due to multiple parameters used in comprehensive stress testing and the variable weight of covariates [2].

Aim

To assess SE outcome data analysis with ML approach.

Methods

We included 6,881 prospectively recruited and retrospectively analyzed patients (median age 67 years, IQR 59–74) with suspected (n=4,279) or known (n=2,602) coronary artery disease submitted to clinically-driven dipyridamole SE in 5 Italian institutions (Figure 1). The primary outcome measure was all-cause death. A Random Forest Survival model has been implemented to model the survival function according to the patient's characteristics. The Random Forest predicted response dependency on covariates has been investigated by reporting the variable dependence and the partial dependency plot (Figure 2). A web application was developed to predict the survival function according to the patients' characteristics. The external validation cohort was made of additional 1,002 patients recruited by a single, independent center in the same time period.

Results

During a median duration of follow-up of 3.4 years (IQR 1.6–7.5), 814 (12%) patients died. The mortality risk was higher for patients aged more than 60 years, resting ejection fraction <60%, resting WMSI, positive delta WMSI scores, and CFVR <3.0. The C-index performance (perfect prediction=1) was 0.79 in the internal validation cohort and 0.81 in the external, independent validation data set. Survival functions for individual patient were easily obtained with an open-access web-app.

Conclusion

An ML approach can be fruitfully applied to outcome data obtained with SE. Survival showed a constantly increasing relationship between survival and CFVR <3.0 and stress-rest wall motion score index >0. Since processing is largely automated, this approach can be easily scaled to larger and more comprehensive data sets to further refine stratification, guide therapy and be ultimately adopted as an open-source on-line decision tool.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The study was partially funded by CNR-MIUR (National Research Council, Italian Ministry of University and Research) Ageing subproject.

Prognostic value of coronary flow and heart rate reserve in emergency department chest pain

Aims

To estimate the prognostic value of stress echo (SE) with the assessment of coronary flow velocity reserve (CFVR) and heart rate reserve (HRR) in patients admitted for chest pain with non-diagnostic EKG, negative troponin, and without inducible regional wall motion abnormalities (RWMA).

Methods

658 patients (age 67±12 years) admitted to our Emergency Department with chest pain, non-diagnostic EKG, and negative serial troponin underwent dipyridamole (0.84 mg/kg in 6') SE with simultaneous assessment of RWMA, CFVR in the left anterior descending artery, and HRR as peak/rest heart rate. The outcome measure was all-cause mortality.

Results

Of the 658 patients initially enrolled, 20 (3%) showed RWMA during SE and were referred to ischemia-driven revascularization. In the remaining 638, CFVR was abnormal (<2.0) in 148 patients (23%). HRR was abnormal (<1.22 in patients in sinus rhythm, or <1.17 in patients with permanent atrial fibrillation) in 196 patients (31%). The main clinical and echocardiographic characteristics according to CFVR and HRR response are shown in Table 1. During a follow-up of 7.3±4.3 years, 151 (24%) patients died. Survival at 8 years was 93% in patients with normal CFVR and HRR, 76% in patients with abnormal CFVR only, 73% in patients with abnormal HRR only, and 38% in those with abnormal CFVR and HRR (p<0.0001) (Figure 1). At multivariable analysis, abnormal CFVR (HR 1.49, 95% CI 1.05–2.10, p=0.02) and abnormal HRR (HR 2.01, 95% CI 1.43–2.84, p<0.0001) were independent predictors of survival.

Conclusions

In admitted patients with non-ischemic EKG, negative serial troponin, and whitout RWMA during dipyridamole SE, a reduced CFVR and blunted HRR independently identify a subset with worse survival in the long-term.

Funding Acknowledgement

Type of funding sources: None.

Prognostic value of rest B-lines with the simplified 4-site scan for predicting survival: incremental value over transthoracic echocardiography

Background

Lung ultrasound (LUS) detects pulmonary congestion as B-lines at rest.

Methods

After preliminary exclusion of 154 patients lost to follow-up, we analyzed transthoracic echocardiography (TTE) plus LUS (4-site simplified scan) data in 5165 subjects (age 64±11 years) referred to 19 certified centers of 9 countries for known or suspected coronary artery disease (n=3891, 75%), dyspnea (n=591, 12%), or screening in asymptomatic patients with risk factors (n=667, 13%). We analyzed the anterior and lateral hemi-thoraces, scanning from mid-axillary to mid-clavicular lines on the third intercostal space. B-lines score ranged from 0 (normal) to 40 (severely abnormal). By selection, follow-up information was available in all. All-cause death was the predetermined end-point.

Results

Feasibility of B-lines was 100% in all subjects. B-lines (median) were 0.1 [0–1]. Rest B-lines (≥2) were present in 863 patients (16.7%). Ejection fraction was 61±10%. After a median follow-up of 690 (Interquartile range 420–1065) days, 96 all-cause deaths occurred. Two-year mortality was 3.6% in patients with and 1.5% in patients without B-lines (p<0.001) and increased progressively with the increasing number of B-lines, from 2.4% in mild (2–4, n=630), 5.0% in moderate (5–9, n=160) and 8.2% in patients with severe (≥10, n=73) B-lines (see figure). At multivariable analysis, rest B lines (HR 1.812, 95% CI: 1.165–2.916, p=0.008) and ejection fraction (HR 0.987, 95% CI: 0.976–0.998, p=0.020) were independent predictors of all-cause death, in addition to age (HR 1.045, 95% CI: 1.023–01.067, p<0.001) and diabetes (HR 1.643, 95% CI: 1.079–2.503, p=0.021).

Conclusion

In all-comers referred for TTE, resting B-lines assessed by focused LUS with the simplified 4-site scan are detected in 1 out of 4 patients with symptos or coronary risk factors and are associated with worse survival. The severity of pulmonary congestion predicts the severity of outcomes. The prognostic value of resting B-lines is independent and additive over standard clinical and TTE predictors such as diabetes and ejection fraction. Focused LUS for pulmonary congestion can easily be incorporated in standard TTE examination.

Funding Acknowledgement

Type of funding sources: None.

The ischemic cascades in contemporary patients: five distinct phenotypes assessed by ABCDE stress echocardiography

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Stress Echo 2020 study group of the Italian Society of Echocardiography and Cardiovascular Imaging (SIECVI)

Background

The classical pathophysiological cornerstone of stress cardiac imaging is the ischemic cascade: alterations in coronary flow velocity reserve (CFVR) come first, regional wall motion abnormalities (RWMA) second, and global alterations of left ventricular diastolic and systolic function last.

Aim

To evaluate the ischemic cascade with stress echo (SE) assessed with ABCDE protocol.

Methods

We analyzed 1616 patients (age 66 ± 10 years, 1156, 72% males) with chest pain and angiographically documented coronary artery disease (CAD): 928 (57.4%) with previous myocardial infarction and 1451 (89.8%) with previous coronary revascularization. CAD patients were studied with ABCDE-SE protocol by 13 certified laboratories of 5 countries. Stress modality was exercise in 427 (26.4%) dobutamine in 173 (10.7%) and vasodilator stress in 1016 (62.9%) patients (dipyridamole in 982 – 60.8% and adenosine in 34 – 2.1% patients). Step A assessed RWMA; step B, B-lines (diastolic function); step C, left ventricular contractile reserve based on force; step D, CFVR in left anterior descending artery; step E, heart rate reserve. SE response ranged from score 0 (all steps normal) to score 5 (all steps abnormal). Follow up was obtained in all patients.

Results

Results were abnormal in 350 (21.7) % for step A, 572 (35.4%) for B, 666 (41.2%) for C, 546 (33.5%) for D and 643 (39.8%) for E. The distribution of positivity is shown in figure. The dominant "solitary phenotype" (only one biomarker abnormal during the test) was step A in 10 (0.6%), step B in 124 (7.7%) step C in 100 (6.2%), step D in 64 (4.0%) and step E in 157 (9.7%) patients. The overall sensitivity for CAD detection including each step of ABCDE score (≥1) was 95.7%. During median follow-up of 22 months [IQ range: 13-37 months] 279 coronary revascularizations occurred. ABCDE score predicted coronary revascularization with score 1: HR: 3.182, 95% CI: 1.699-6.067; score 2: HR: 4.921, 95% CI: 2.571-9.420; score 3: HR: 7.234, 95% CI: 3.743-13.979; score 4: HR: 24.570, 95% CI: 13.390-45.086; and score 5: HR: 38.720, 95% CI: 20.975-71.478

Conclusion

Inducible ischemia with CAD is characterized by the complexity and multiplicity of diagnostic phenotypes. The overall ABCDE score predicts clinically driven revascularization. Abstract Figure. The 5 circles of ischemia biomarkers

Left ventricular contractile reserve, coronary flow reserve, and heart rate reserve during dipyridamole stress echocardiography predict survival in non-ischemic heart failure

Background

Left ventricular contractile reserve (LVCR), coronary flow velocity reserve (CFVR), and heart rate reserve (HRR) have recognized independent impact on outcome in heart failure (HF). They all can be simultaneously measured during dipyridamole stress echocardiography (DSE).

Aim

To assess the value of comprehensive DSE in patients with non-ischemic heart failure.

Methods

We evaluated 613 patients with HF, no history of coronary artery disease and no inducible regional wall motion abnormalities: 270 patients with preserved (≥50%) ejection fraction; 147 with mid-range (40–49%) ejection fraction; 196 with HF and reduced (<40%) ejection fraction. All underwent DSE (0.84 mg/kg in 6') in 5 accredited laboratories. We measured LVCR (abnormal value ≤1.1), CFVR in left anterior descending artery (abnormal value ≤2.0), and HRR (peak/rest heart rate, abnormal value ≤1.22). All patients were followed-up.

Results

Abnormal CFVR, LVCR and HRR occurred in 29%, 44% and 46% of patients, respectively. After a median follow-up time of 20 months (interquartile range 12–32 months), 41 patients died. Annual mortality rate was lowest in patients (n=200) with normal response, and >10-fold higher in patients (n=96) with 3 abnormal criteria: see figure. At multivariable analysis, a reduced HRR (Hazard Ratio = 3.402, 95% Confidence Intervals 1.530–7.565, p=0.003) was the strongest SE independent predictor of all-cause death.

Conclusion

Abnormal LVCR, CFVR and HRR can be frequently observed during vasodilator SE in HF patients. They target different pathophysiological vulnerabilities (myocardial function, coronary microcirculation and cardiac autonomic system) and are useful for outcome prediction.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Consiglio nazionale delle ricerche - Institute of Clinical Physiology Figure 1

Comparison of coronary flow reserve feasibility and values in different stress echocardiography protocols: dobutamine, dipyridamole, exercise and rapid pacing

Background and aims

To compare the feasibility of Coronary Flow Velocity Reserve (CFVR) assessment in the left anterior descending (LAD) artery in four types of stress echocardiography (SE): dobutamine (DOB), dipyridamole (DIP), rapid pacing (PAC) and bicycle exercise (EXE).

Methods and results

We subjected 369 patients (mean age: 67±11 years) to SE with DOB (up to 40 mcg/kg/min, n=230), DIP (0.84 mg/kg, n=73), PAC (n=22) or EXE (n=44). CFVR was measured as the ratio of peak diastolic coronary flow velocity (CFV) during exercise, pharmacological stress or pacing and peak diastolic CFV at rest in distal or mid LAD.

The feasibility was excellent during PAC (100%), DOB (95%) and DIP (95%) and lower during EXE (73%, p<0.01 vs other groups) when assessed in all consecutive patients. When assessed in patients having readable LAD flow at rest the feasibility achieved even higher values, being however still lowered in EXE group, see Figure 1.

In multivariate analysis only the EXE protocol was a predictor of LAD flow loss during SE, with OR = 8.23 (95% CI 2.17 – 31.33), p=0.0019. CFVR was lower with PAC (1.8±0.4) as compared to DIP (2.2±0.6, p=0.0061) and DOB (2.2±0.6, p=0.0025), but similar to EXE (2.0±0.6, p=0.178), and correlated best with the peak heart rate in EXE and PAC, see Figure 2.

Conclusion

CFVR in LAD can be obtained during all forms of SE, but the feasibility is significantly higher with PAC and pharmacological tests as compared to EXE, which was identified in our study as the independent predictor of the loss of LAD flow recording at the peak of stress test. Moreover, CFVR values were the lowest in PAC group which however encompassed the older patients with more advanced coronary artery disease. Significant correlation between HR and CFVR observed in EXE and PAC suggests that in this type of SE cut-off value of CFVR should be probably indexed to maximal HR achieved.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Prognostic value of ABCDE stress echocardiography

Background

Stress echocardiography (SE) was recently upgraded to the ABCDE protocol: step A, regional wall motion abnormalities; step B, B-lines; step C, left ventricular contractile reserve; step D, Doppler-based coronary flow velocity reserve in left anterior descending coronary artery; and step E, EKG-based heart rate reserve. Aim: to assess the prognostic value of ABCDE-SE in a prospective, large scale, multicenter, international, effectiveness study.

Methods

From July 2016 to November 2020, we enrolled 3,574 all-comers (age 65±11 years, 2,070 males, 58%; ejection fraction 60±10%) with known or suspected chronic coronary syndromes referred from 13 certified laboratories. All patients underwent ABCDE-SE. The employed stress modality was exercise (n=952, with semi-supine bike, n=887, or treadmill, n=65 with adenosine for step D) or pharmacological stress (n=2,622, with vasodilator, n=2,151; or dobutamine, n=471). SE response ranged from score 0 (all steps normal) to score 5 (all steps abnormal). All-cause death was the only end-point.

Results

Rate of abnormal results was 16% for A, 30% for B, 36% for C, 28% for D and 37% for E step. During a median follow-up of 21 months, 73 deaths occurred. At univariable analysis, predictors of all-cause mortality were step B (hazard ratio, HR: 2.621, 95% Confidence Intervals, CI: 1.654–4.152, p<0.001), step D (HR: 2.578, 95% CI: 1.624–4.093, p<0.001), and step E (HR: 2.955, 95% CI: 1.848–4.725, p<0.001), but not step A (HR: 1.333, 95% CI: 0.731–2.430, p=0.349) and step C (HR1.581, 95% CI: 0.997–2.506, p=0.051). At multivariable analysis, ABCDE-SE was an independent predictor of mortality with score 3 (HR: 3.472, 95% CI: 1.483–8.135, p=0.004), 4 (HR: 4.045, 95% CI: 1.595–10.259, p=0.003) and 5 (HR: 5.678, 95% CI: 2.106–15.313, p=0.001) (Figure). Annual mortality rate ranged from 0.4% person/year for score 0 up to 2.4% person/year for score 5.

Conclusion

ABCDE-SE allows an effective risk stratification of patient global vulnerability.

Funding Acknowledgement

Type of funding sources: None. Survival curves based on ABCDE score

Additive prognostic value of coronary flow and heart rate reserve during vasodilator stress echocardiography in hypertrophic cardiomyopathy

Background

Coronary flow velocity reserve (CFVR) and heart rate reserve (HRR) during vasodilator stress echocardiography (SE) assess coronary microvascular function and cardiac sympathetic reserve respectively. Both CFVR and HRR can be impaired in hypertrophic cardiomyopathy (HCM).

Objectives

To evaluate the prognostic value of CFVR and HRR during vasodilator SE in HCM.

Methods

We enrolled 244 HCM patients (age=51±15 years, 116 men) studied with vasodilator SE from 1999 to 2019 in 5 certified centers. Stress modality was either adenosine (Ado, 0.14 mg/kg/min in 2', n=171) or dipyridamole (Dip, 0.84 mg/kg in 6', n=73). Left ventricular outflow tract obstruction was present at rest in 80 patients (33%). We assessed CFVR in left anterior descending coronary artery (by TTE in 225, and TEE in 19 patients) and HRR (peak/rest heart rate). Abnormal values of HRR were based on receiver operating characteristics for Ado and Dip separately calculated. All patients completed the follow-up.

Results

CFVR was 2.17±0.46 for Dip and 2.13±0.43 for Ado (p=ns); HRR was 1.36±0.19 for Dip and 1.10±0.16 for Ado (p<0.001). An abnormal CFVR (<2.0 for both Ado and Dip) was present in 28 patients for Dip and 73 for Ado (38% vs 43%, p=ns). An abnormal HRR (≤1.34 for Dip and ≤1.03 for Ado) was present in 39 patients for Dip and in 70 patients for Ado (53% vs 41%, p=ns). During a median follow-up of 67 months (interquartile range: 29–103 months), 97 spontaneous events occurred in 71 patients: 29 all-cause deaths, 32 new hospital admission for acute heart failure, 3 sustained ventricular tachycardias, 32 atrial fibrillations and 1 heart transplantation. Event rate was 2.5%/year in patients with normal CFVR and HRR, 4.7%/year in patients with only one abnormal criterion and 10.9%/year in patients with abnormal responses of both criteria (see figure). At multivariate analysis, abnormality of both CFVR and HRR (Hazard ratio 4.033, 95% CI 1.863–8.729, p<0.001) was independent predictor of events.

Conclusions

A reduced CFVR and blunted HRR during vasodilator SE identify distinct phenotypes and show independent value in predicting outcome in HCM patients.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Kaplan-Meier spontaneous event-free survival curves based on HRR and CFVR. Kaplan-Meier survival curves (considering spontaneous events) in patients stratified with the abnormal HRR and/or CFVR. Number of patients at risk per year is shown.

Hemodynamic heterogeneity of inadequate cardiac output increase identified by 2-dimensional volumetric exercise echocardiography: slow, stiff or weak heart?

Background

Two-dimensional (2-D) volumetric exercise stress echocardiography (ESE) provides an integrated view of preload reserve through end-diastolic volume (EDV) and left ventricular contractile reserve (LVCR) through end-systolic volume (ESV) changes.

Purpose

To assess the dependence of stroke volume (SV) and cardiac output (CO) upon LVCR EDV changes and heart rate (HR) during ESE.

Methods

We prospectively performed semi-supine bicycle or treadmill ESE in 1,344 patients (age 59.8±11.4 years; 550 female; ejection fraction = 62.5±8%) referred for known or suspected coronary artery disease in 20 quality controlled laboratories of 16 countries from 2016 to 2019. SV was calculated at rest and peak stress from raw measurement of LV EDV and ESV by biplane Simpson rule, 2-D echo. LVCR was the stress-rest ratio of force (systolic blood pressure by cuff sphygmomanometer/ESV, abnormal values <2.0 identify a “weak” heart). Preload reserve was defined by an increase in LV EDV. Abnormal values (lack of EDV increase, peak EDV ≤ rest EDV) identify a “stiff” heart. Cardiac output was calculated as SV * HR (measured with standard EKG). HR reserve (stress/rest ratio) <1.85 identifies a “slow” heart with chronotropic incompetence.

Results

By selection, all patients had negative SE by wall motion criteria. Of the 1,344 patients included in the study, 448 belonged to the lowest tertile of CO increase. Of them 326 (73%) achieved HR reserve <1.85; 220 (49%) had a blunted LVCR and 374 (83%) a reduction of preload reserve, with 348 patients (78%) showing ≥2 abnormalities. The more the abnormal criteria, the worse the CO response, which was lowest in slow, stiff and weak hearts: see figure.

Conclusion

Patients with normal CO reserve during exercise usually have a fast, compliant and strong heart. Abnormal CO reserve is associated with heterogeneous hemodynamic responses, with slow, stiff and/or weak hearts. The clarification of underlying hemodynamic heterogeneity is the prerequisite for a personalized treatment, and can be easily extracted from a standard 2-D volumetric SE. Hearts with normal CO are all alike; every heart with abnormal CO is abnormal in its own way.

CO % changes in subsets (*p<0.001)

Funding Acknowledgement

Type of funding source: None

Functional correlates of left atrial volume dilatation during vasodilator stress echocardiography

Background

Exercise and dobutamine stress may induce acute left atrial volume index (LAVI) dilatation in 1 out 10 patients. The effect of vasodilator stress in LAVI remains unknown.

Purpose

To assess the feasibility and functional correlates of LAVI change during dipyridamole stress echocardiography (SE).

Methods

We studied 149 patients (99 male, age 66±10 years, ejection fraction 59±8%, 64 with previous myocardial infarction), who underwent dipyridamole ABCDE-SE. LAVI was measured with the biplane disk summation method at rest and peak stress: LAVI-dilators were defined as those with stress-rest increase ≥6.8 ml/m2. Criteria for abnormal response of ABCDE-SE were: stress-induced changes in regional wall motion abnormalities (RWMA) for step A; B-lines at peak stress ≥2 for step B (4-site simplified scan, each site scored from 0= A-lines or black lung to 10= white lung for coalescing B-lines); reduced left ventricular contractile reserve (LVCR, peak/ rest based on force) ≤1.1 for step C; abnormal coronary flow velocity reserve (CFVR) ≤2.0, assessed by pulsed wave Doppler sampling in left anterior descending coronary artery for step D; abnormal heart rate reserve (HRR, peak/rest heart rate) ≤1.22 for step E.

Results

LAVI dilation occurred in 13 patients (9%). The positivity was for step A: RWMA in 6 pts (4%); step B: presence of peak B-lines in 12 pts (8%); step C: abnormal LCVR in 14 pts (9%); step D: reduced CFVR in 17 pts (11%) and step E: abnormal HRR in 46 pts (31%). LAVI dilators showed significantly higher incidence of positivity of steps A-B-C-D (see figure) compared to patients without LAVI dilatation.

Conclusion

Evaluation of LAVI change during vasodilator SE is feasible, and LAVI dilatation is more frequently found with ischemic (step A), wet (step B), weak (step C) and cold (step D) heart.

Figure 1

Funding Acknowledgement

Type of funding source: None

The spectrum of functional responses during ABCDE stress echocardiography

Background

The new methodological standard in stress echo (SE) is the comprehensive approach with ABCDE protocol: step A for regional wall motion abnormalities (RWMA); step B for B-lines by lung ultrasound; step C for left ventricular contractile reserve (LVCR); step D for Doppler-based coronary flow velocity reserve (CFVR) in left anterior descending coronary artery; and step E for imaging-independent EKG-based heart rate reserve (HRR).

Purpose

To assess the feasibility of ABCDE-SE in a prospective, large scale, multicenter, international, effectiveness study.

Methods

From September 2016 to December 2019, we enrolled 4,585 all-comers patients (age 63±11 years, 2,566 males, 56%; ejection fraction 61±9%) with known or suspected chronic coronary artery disease referred to clinically-driven SE with exercise (n=1,774, 38.7%), dipyridamole (n=2,403, 52.4%), dobutamine (n=375, 8.2%) or adenosine (n=33, 0.7%). Recruitment involved 13-certified laboratories of 7 countries. All patients underwent ABCDE-SE. The same transducer was used for cardiac and lung scan. Criteria for abnormal response were: stress-induced changes in RWMA in 2 contiguous segments for step A; stress-rest increase in B-lines ≥2 for step B (4-site simplified scan, each site scored from 0= A-lines or black lung to 10= white lung for coalescing B-lines); LVCR ≤2.0 for exercise and dobutamine (≤1.1 for vasodilators) for step C; CFVR in LAD ≤2.0 for step D; HRR (peak/rest heart rate) ≤1.80 for exercise and dobutamine (≤1.22 for vasodilators) for step E.

Results

Success rate was 98%, 100%, 99%, 86% and 100% for A, B, C, D and E steps, respectively. The positivity rate was 19% for A, 27% for B, 35% for C, 27% for D and 37% for E. All 5 parameters were normal in 1,496 patients (32.6%), all 5 were abnormal in 183 patients (4.0%). Most patients had abnormal response of 1 (n=1,356, 29.6%), 2 (n=788, 17.2%), 3 (n=477, 9.7%) or 4 (n=315, 6.9%) criteria (see Figure).

Conclusions

ABCDE-SE is extremely feasible, user-friendly, with minimal increase in imaging and off-line analysis time. It allows a comprehensive and personalized functional stratification assessing different vulnerabilities: epicardial coronary artery stenosis (step A), pulmonary congestion (step B), global myocardial dysfunction (step C), coronary microcirculatory dysfunction (step D), and cardiac autonomic nervous system imbalance (step E). The SE response is not only black and white with step A but can be effectively titrated from benign green code (all steps negative) to more functionally malignant red code (at least 3 steps positive).

Figure 1

Funding Acknowledgement

Type of funding source: None

The additive prognostic value of B-lines and heart rate reserve during “kindergarten” stress echocardiography

Background

B-lines by lung ultrasound (LUS) were added to stress echo (SE) as a direct sign of pulmonary congestion useful to establish an objective link between dyspnoea symptoms and acute heart failure. They are feasible with “kindergarten” training of few hours and pocket size instruments.

Aim

To assess the prognostic value of “kindergarten SE” only based on B-lines and imaging-independent heart rate reserve (HRR).

Methods

We enrolled 2,149 patients (age 63±16 yrs, 831 women, 39%) with known or suspected coronary artery diseasereferred for exercise (n=1,015), dipyridamole (n=1,039), adenosine (n=16) or dobutamine (n=79) SE. By LUS, we adopted the 4-site simplified scan, each site scored from 0=normal A-lines, to 10=coalescing B-lines. HRR was assessed as peak/rest ratio of heart rate. All patients were followed-up.

Results

Interpretable HRR and LUS data were obtained in all patients (feasibility=100%). Abnormal B-lines (≥2) at peak stress were present in 756 patients (35%). Abnormal HRR (≤1.80 for exercise and dobutamine and ≤1.22 for vasodilator) was found in 986 patients (46%), both positivity in 388 patients (18%). During a median follow-up time of 15 months, 137 spontaneous events occurred in 120 patients: 38 deaths, 28 myocardial infarctions, 60 acute heart failures, 11 strokes. B-lines ≥2 and/or reduced HRR were independently associated with adverse outcome (see figure). At multivariable analysis, a three-fold increased risk of death was observed when both B-lines and HRR were abnormal (Hazard ratio: 3.097, 95% Confidence Intervals 1.095–8.754, p=0.03).

Conclusions

A super-simplified stress test (“SE without SE”) with simple heart rate assessment by EKG and LUS for B-lines evaluates key variables such as chronotropic incompetence (due to reduced sympathetic reserve) and pulmonary congestion (due to backward acute heart failure) and allows an accurate prediction of outcome.

Figure 1

Funding Acknowledgement

Type of funding source: None

Prognostic role of coronary flow velocity reserve in hypertrophic cardiomyopathy

Background

A reduction in coronary flow velocity reserve (CFVR) related to coronary microvascular dysfunction is a major mechanism for ischemia in hypertrophic cardiomyopathy (HCM).

Hypothesis

To assess the functional correlates and prognostic value of CFVR during stress echocardiography (SE) in HCM.

Methods

We enrolled 201 HCM patients (age 51±14 years, 105 male, 52%; maximal wall thickness: 18±3 mm) studied with CFVR during exercise (n=33, 16.4%), dipyridamole (n=89, 44.3%) or adenosine (n=79, 39.3%) SE in 6 certified centers. CFVR was assessed using pulsed wave Doppler sampling in left anterior descending coronary artery. All patients completed the clinical follow-up.

Results

During SE mean value of CFVR was 2.11±0.46. No patients showed regional wall motion abnormalities during stress. LV outflow tract obstruction (LVOTO) was present in 34 (16.9%) patients at rest and in 47 (23.4%) at peak stress. CFVR was inversely related to age (r=−0.229, p=0.001) and maximal wall thickness (r=−0.197, p=0.031). During a median follow-up of 26 months (IQ range: 12–48 months), 75 events in 63 patients occurred: 10 deaths, 33 new hospital admission for acute heart failure, 8 sustained ventricular tachycardias and 24 atrial fibrillations. Patients in the lowest tertile (≤1.88) showed the worse prognosis with higher incidence of follow-up events compared to median tertile (1.89–2.29) and highest tertile (≥2.30) (see figure). At multivariable analysis, NYHA functional class (HR: 2.234, 95% CI: 1.398–3.517, p=0.001), presence of LVOTO at rest (HR: 2.958, 95% CI: 1.074–3.570, p=0.028) and lowest tertile of CFVR (HR: 2.144, 95% CI: 1.126–4.081, p=0.011) were the independent predictors of follow-up events.

Conclusions

In HCM patients, reduction in CFVR is associated to a clearly worse outcome. The spectrum of prognostic stratification is expanded if the response is titrated according to a continuous scale.

Figure 1

Funding Acknowledgement

Type of funding source: None

P1793 Blunted heart rate reserve during exercise or vasodilator stress echo is a predictor of outcome

OnBehalf

Stress Echo 2020 study group of the Italian Society of Cardiovascular Imaging

Background

A blunted heart rate reserve (HRR) during exercise or vasodilator stress echo (SE) has been associated with a poor outcome in retrospective studies.

Aim. To assess the prognostic value of HRR in patients undergoing SE in prospective study.

Methods

We prospectively recruited a sample of 1825 patients (none with pacemakers or atrial fibrillation; mean age 63 ± 11 years; 1099 male, 60%; 1125, 62% on beta-blockers at the time of testing). All underwent SE with either exercise (n= 631, 543 with semi-supine bicycle and 88 with post-treadmill) or vasodilator (n = 1194, 1184 with accelerated high dose dipyridamole and 10 with adenosine) SE for evaluation of known or suspected coronary artery disease and/or heart failure in 7 accredited laboratories of 5 countries. HRR was calculated by ECG as the peak/rest HR ratio. All patients were followed-up.

Results

During a median follow-up time of 480 days, 211 events occurred: 20 deaths, 22 non-fatal myocardial infarctions, 58 hospital admissions for acute decompensated heart failure and 111 late (> 3 months from SE) myocardial revascularizations. Positivity cutoff for HRR identified by ROC analysis was ≤1.67 (sensitivity 51.0, specificity 63.4) in the exercise group and ≤1.32 (sensitivity 65.0, specificity 48.9) in the vasodilator group. The separation was present both in the exercise (left panel) and the vasodilator (right panel) subsets : see figure. At multivariable analysis, blunted HRR was an independent predictor of event-free survival in the overall group (Hazard Ratio 1.422, 95 % Confidence Intervals: 1.055-1.917, p=.021), independent of beta-blocker therapy.

Conclusion

A blunted HRR is a useful non-imaging predictor of adverse events during both vasodilator and exercise SE, independent of inducible ischemia and beta-blocker therapy.

Abstract P1793 Figure. HRR and event-free survival curves

P1792 Coronary flow velocity reserve and prognosis during stress echocardiography

OnBehalf

Stress Echo 2020 study group of the Italian Society of Cardiovascular Imaging

Background

Stress echocardiography (SE) based on regional wall motion abnormalities (RWMA) has established risk stratification capabilities, further enhanced by assessment of coronary flow velocity reserve (CFVR) on mid-distal left anterior descending coronary artery which assesses not only epicardial coronary artery stenosis but also coronary microcirculation.

Aim

To assess the value of CFVR in predicting outcome

Methods

From September 2016 to December 2018, we enrolled 1848 patients (age 63 ± 11 years; 1121 males, 60%) with known or suspected coronary artery disease and/or heart failure evaluated with SE (exercise in 631, dipyridamole in 1184, adenosine in 10, dobutamine in 43) in 9 quality-controlled centers of 6 countries. CFVR was measured from pulsed wave Doppler as peak/rest ratio of peak diastolic flow. All patients were followed-up for a median of 16 months.

Results CFV was 28 ± 10 cm/s at rest and 62 ± 19 cm/s at peak stress (p<.001) with a CFVR of 2.25 ± 0.58. At individual patient analysis, CFVR was abnormal (≤2.0) in 528 (28%) patients: 265 (42%) with exercise, 254 (21%) with vasodilator and 9 (21%) with dobutamine stress. At follow-up, there were 218 events: 22 deaths, 22 non-fatal myocardial infarctions, 62 acute heart failures, and 112 late (> 3 months from SE) myocardial revascularizations. At multivariable analysis, stress-induced RWMA (Hazard Ratio 3.883, 95% Confidence Intervals: 2.379-6.336, p<.0.001) and CFVR (Hazard Ratio 1.590, 95% Confidence Intervals: 1.123-2.275, p<.009) were independent predictors. Kaplan-Meier curves showed progressively worsening event-free survival with progressively lower values of CFVR: see figure

Conclusion In patients referred to SE, CFVR assessing coronary microvascular dysfunction allows a more accurate prediction of outcome than RWMA which only detect epicardial coronary artery stenoses.

Abstract P1792 Figure. CFVR and event-free survival curves

P1401 The prognostic value of the reduction of coronary flow velocity reserve in non-ischemic heart failure patients

OnBehalf

Stress Echo 2020 study group of the Italian Society of Cardiovascular Imaging

Background

Coronary microvascular abnormalities determining a reduction of coronary flow velocity reserve (CFVR) have been described in patients (pts) with non-ischemic heart failure (HF).

Aim

To assess the prognostic value of CFVR in HF.

Methods

In a prospective, observational, multicenter study, we recruited 333 pts with angiographically normal coronary arteries: 105 patients with HF and preserved (>50%) ejection fraction (HFpEF); 71 with HF and mid-range (40-50%) ejection fraction (HFmrEF); 157 with HF and reduced (<40%) ejection fraction (HFrEF). All patients underwent vasodilator SE with dipyridamole (0.84 mg/kg) in 10 accredited laboratories of 5 countries (Argentina, Brazil, Italy, Mexico, Serbia). CFVR was calculated as the stress/rest ratio of diastolic peak flow velocity pulsed wave-Doppler assessment of LAD flow. In all patients we also assessed left ventricular contractile reserve (LVCR) based on force (systolic blood pressure/end-systolic volume) Abnormal cutoff values were ≤2.0 for CFVR and ≤1.1 for LVCR. All pts were followed-up.

Results

After a median follow-up time of 15 months, 78 events occurred: 36 hospital admissions for acute decompensated heart failure, 23 deaths, 16 worsening in NYHA functional class, 2 stroke and 1 late revascularization. Event-free survival was best in patients with preserved CFVR and LVCR and worst in pts with reduced CFVR and impaired LVCR, with intermediate values for patients with either one (CFVR or LVCR) abnormal results: see figure. A preserved CFVR was associated with a better 24-month event-free survival than reduced CFVR in a subset analysis in pts with HFpEF (HR = 16.2, 95% CI, 1.8-145.1, p = 0.001) and in HFrEF (HR = 3.06, 95% CI, 1.6-5.6, p < 0.001). A multivariable analysis in the overall group of HF pts identified a reduced CFVR as the only independent predictor of event-free survival (HR = 3.455,95% CI 1.723-6.929).

Conclusions

A reduction in CFVR identifies a high risk subset in HF patients, outlining a shared role of coronary microvascular abnormalities as a marker and potential therapeutic target of HF, independently of underlying EF.

Abstract P1401 Figure. Event-free survival based on CFVR-LVCR

P1791 Outcome prediction with regional wall motion abnormalities during stress echocardiography

OnBehalf

Stress Echo 2020 study group of the Italian Society of Cardiovascular Imaging

Background

Over the last 3 decades, we observed a progressive decline in the prognostic value of a negative stress echo (SE) test based on regional wall motion abnormalities (RWMA), likely reflecting both an increase in risk in patients (older and more often diabetics) as well as a potential decrease in test performance due to concomitant anti-ischemic therapy.

Aim

To assess the value of SE in predicting outcome in contemporary populations

Methods

From September 2016 to December 2018, we enrolled 1848 patients (age 63 ± 11 years; 1121 males, 60%) with known or suspected coronary artery disease and/or heart failure evaluated with SE (exercise in 543, dipyridamole in 1184, adenosine in 10, dobutamine in 43) in 9 quality-controlled centers of 6 countries. Wall motion score index (WMSI) was evaluated at rest and peak stress (17-segment model, from 1 = normal-hyperkinetic to 4 = dyskinetic).All patients were followed-up for a median of 16 months.

Results WMSI was 1.09 ± 0.23 at rest and increased during stress (1.17 ± 0.32, p<.001). At individual patient analysis, inducible ischemia with RWMA was present in 352 pts (18.8%). At follow-up, there were 218 events: 22 deaths, 22 non-fatal myocardial infarctions, 62 hospital admissions for acute heart failures, and 112 late (>3 months from SE) myocardial revascularizations. Multivariable analysis identified stress-induced RWMA (Hazard Ratio 2.754, 95% Confidence Intervals: 2.053-3.963, p<.0.001) as an independent predictor of events. Kaplan-Meier curves showed progressively worsening event-free survival for 1247 pts with normal (WMSI = 1.0), 298 pts with mildly (1.05-1.39), 250 pts with moderately (1.4-1.99) or 73 pts with severely (>2.0) abnormal peak WMSI: see figure. In patients with negative SE, event-rate was 1.4% per year considering hard events (death and myocardial infarction) and 0.8 % per year considering only death.

Conclusion RWMA show risk stratification capability in contemporary patients referred to SE testing. The higher the peak WMSI, and the worse the prognosis. Nevertheless, the positivity rate is low (< 20%) and patients with normal baseline and stress function still have a significant event rate. A more comprehensive risk assessment with other parameters is warranted

Abstract P1791 Figure. Survival curves and peak WMSI

P1403 Prognostic value of B-lines during stress lung ultrasound

OnBehalf

Stress Echo 2020 study group of the Italian Society of Cardiovascular Imaging

Background

B-lines (also known as comets) by lung ultrasound (LUS) are a marker of pulmonary congestion and interstitial pulmonary edema during stress echocardiography (SE).

Aim

To assess the prognostic value of B-lines during SE.

Methods

We prospectively performed transthoracic echocardiography (TTE) and LUS (4-site simplified scan) evaluation at rest and peak stress in 1437 patients (age 63 ± 11 years; 874 males, 61%) referred for exercise (n = 581), vasodilator (n = 819: dipyridamole, n= 809 and adenosine, n= 10) or dobutamine (n = 37) SE for known or suspected coronary artery disease or heart failure. B-lines were assessed by LUS with a 4-site simplified scan (total score from 0-1, dry lung, to 40, alveolar pulmonary edema). Follow-up (median 16 months) was completed in all.

Results

B-lines were 1.14 [0-35] at rest and increased during stress (2.10 [0-40], p<.001). At individual patient analysis, B-lines appeared de novo/increased (≥2 points) during stress in 306 (21.3%), remained absent or fixed in 1097 (76.3%) and decreased/disappeared in 34 (2.4%). At follow-up, there were 174 events: 17 deaths, 14 non-fatal myocardial infarctions, 51 hospital admissions for acute heart failures, and 92 late (> 3 months from SE) myocardial revascularizations. At multivariable analysis, stress-induced regional wall motion abnormalities (Hazard Ratio, HR, 2.842, 95% Confidence Intervals, CI: 2.016-4.005, p<.0.001) and B-lines change during stress (HR 1.471, 95% CI: 1.054-2.052, p=.022) were independent predictors. Kaplan-Meier curves showed progressively worsening event-free survival for 943 pts with absent (score 0-1), 333 with mild (2-5), 90 with moderate (6-10) and 71 with severe (>10) B-lines at peak stress: see figure.

Conclusion

B-lines by LUS are a useful adjunct to regional wall motion abnormalities for risk stratification during SE. The presence and number of B-lines during stress allow a titration of risk. The outcome is darker with more comets in the SE sky.

Abstract P1403 Figure. Survival curves and peak stress B-lines

1675 ABCDE vasodilator stress echocardiography in non-ischemic heart failure

OnBehalf

Stress Echo 2020 study group of the Italian Society of Cardiovascular Imaging

Background

ABCDE-stress echocardiography (SE) may explore different aspects in the heterogeneous entity of known or suspected heart failure (HF).

Aim

To assess ABCDE-vasodilator SE in non-ischemic HF

Methods

In a prospective, observational, multicenter study, we recruited 428 patients with angiographically normal coronary arteries: 148 patients with HF and preserved (>50%) ejection fraction (HFpEF, Group 1); 100 with HF and mid-range (40-50%) ejection fraction (HFmrEF, Group 2); 180 with HF and reduced (<40%) ejection fraction (HFrEF, Group 3). A group of 75 healthy asymptomatic patients (30 male, 40%, age 57 ± 14 years) referred to testing for screening was also selected (Controls). All patients underwent vasodilator SE with dipyridamole (0.84 mg/kg) in 14 accredited laboratories of 5 countries (Argentina, Brasil, Russian Federation, Serbia and Italy). The ABCDE-SE protocol was adopted: A for regional wall motion abnormalities; B for B-lines (positivity criterion: stress ≥ rest for ≥ 2 points in a 4-site simplified scan available in 181 pts and 10 controls); C for left ventricular contractile reserve (LVCR) based on force (systolic blood pressure/end-systolic volume, positivity criterion: peak/ rest ≤1.1); D for pulsed wave Doppler-based assessment of coronary flow velocity reserve (CFVR) in left anterior descending coronary artery (positivity criterion: peak/rest ≤2.0); E for EKG-based assessment of heart rate reserve (positivity criterion: peak/rest ≤1.22).

Results

All positivity criteria, except A, were more prevalent (p<.01) in Group 3 compared to Group 2, in Group 2 compared to Group 1, and Group 1 compared to controls: see figure. In particular, a blunted heart rate reserve was found in 4/75 controls (5%), 27/148 pts of Group 1 (18%), 28/100 of Group 2 (28%) and 98/180 of Group 3 (54%).

Conclusions

ABCDE-vasodilator SE can help to identify the profound pathophysiological heterogeneity underlying a similar clinical presentation in patients with known or suspected HF with angiographically normal coronary arteries. These patients rarely show stress-induced regional wall motion abnormalities (A), but may exhibit pulmonary congestion (B), reduced myocardial functional reserve (C), altered coronary microcirculation (D) and cardiac autonomic dysfunction (E).

Abstract 1675 Figure. The positivity rate of ABCDE criteria

P329 Outcome prediction with force-based left ventricular contractile reserve during stress echocardiography

OnBehalf

Stress Echo 2020 study group of the Italian Society of Cardiovascular Imaging

Background

Stress echo (SE) risk stratification is based on regional wall motion abnormalities (RWMA). The assessment of global left ventricular contractile reserve (LVCR) based on load-independent Force may refine prognosis.

Aim

To assess the value of LVCR during SE in predicting outcome

Methods

From September 2016 to December 2018, we prospectively enrolled 1848 patients (age 63 ± 11 years; 1121 males, 60%) with known or suspected coronary artery disease and/or heart failure evaluated with SE (exercise in 543, dipyridamole in 1184, adenosine in 10, dobutamine in 43) in 9 quality-controlled centers of 6 countries. Force was measured at rest and peak stress as the ratio of systolic blood pressure by cuff sphygmomanometer/end-systolic volume by 2D and biplane Simpson method of disks. When Simpson method was not feasible, apical single plane or linear parasternal methods were used to calculate volumes. Abnormal values of LVCR (peak/ rest) based on force were ≤1.10 for dipyridamole and adenosine; ≤1.61 for exercise or dobutamine. All patients were followed-up for a median of 16 months.

Results RWMA and Force-based LVCR were obtained in all pts. Force was 4.24 ± 1.88 mmHg/ml at rest and increased during stress (7.07 ± 4.60 mmHg/ml, p<.001). At individual patient analysis, LVCR was abnormal in 495 (26%) and normal in 1373 (74%) patients. At follow-up, there were 218 events: 22 deaths, 22 non-fatal myocardial infarctions, 62 hospital admissions for acute heart failures, and 112 late (> 3 months from SE) myocardial revascularizations. At multivariable analysis, stress-induced RWMA (Hazard Ratio, HR, 2.899, 95% Confidence Intervals, CI: 2.032-4.137, p<.0.001), force-based LVCR (HR 1.747, 95% CI: 1.245-2.470, p=.002) were independent predictors. Kaplan-Meier curves showed worse event-free survival for pts with abnormal LVCR: see figure.

Conclusion LVCR based on Force is a useful adjunct to RWMA for risk stratification with SE.

Abstract P329 Figure. Survival curves and LVCR

P4982Blunted heart rate reserve as an imaging-independent prognostic predictor during dipyridamole-echocardiography test

Background

A blunted heart rate (HR) response during dipyridamole myocardial perfusion imaging have been associated with a poor outcome.

Aim

To assess the value of HR response in patients undergoing high dose dipyridamole stress echocardiography (SE).

Methods

We retrospectively selected a consecutive sample of 1,622 patients (none with pacemakers or atrial fibrillation), mean age 66±12 years, 431 (27%) on beta-blockers. All underwent high dose (0.84 mg/kg) dipyridamole SE for known or suspected coronary artery disease and/or heart failure from January 1988 to January 2018 in our Cardiology Division. HR (with 12-lead ECG) was obtained each minute and recorded at rest and peak stress. HR reserve (HRR) was calculated as the peak/rest HR ratio. All patients were followed-up. The composite end-point was made of all cause-death, non-fatal myocardial infarction and late (>3 months) symptoms-driven myocardial revascularizations.

Results

SE was positive for regional wall motion abnormalities (RWMA) in 192 patients (12%). HR increased (rest=70±11 beats/min vs stress= 92±17 beats/min, p<0.0001). During a median follow-up time of 904 days, 462 events occurred: 73 deaths, 57 non-fatal myocardial infarctions, 332 myocardial revascularizations. Receiver operating curve analysis identified a HRR ≤1.27 as the best cutoff. At multivariate analysis a reduced HRR was a significant predictor of hard events (Hazard Ratio, HR=2.02, 95% Confidence Intervals, CI, 1.38–2.95, P<0.0001), additive to ischemic regional wall motion abnormalities (HR=2.11, 95% CI 1.28–3.48, P=0.004), resting RWMA (HR =1.88, 95% CI 1.31–2.72, P<0.001), age (HR =1.06, 95% CI 1.04–1.08, P<0.001) and beta-blockers at the time of testing (HR =1.55, 95% CI 1.06–2.29, P=0.03). Five-year hard event-free survival increased from 6% to 26% from the highest to the lowest HRR quartile: see figure.

Survival curve

Conclusion

A blunted HRR is a useful non-imaging predictor of adverse events during high dose dipyridamole-SE. It is additive over resting or inducible regional wall motion abnormalities, and unmasks a prognostically meaningful autonomic unbalance. Chronotropic incompetence during dipyridamole SE is a negative prognostic finding, equally important than RWMA.

P4985Blunted heart rate reserve as an imaging-independent predictor of abnormal left ventricular contractile reserve

Background

Stress echocardiography (SE) relies on regional wall motion and left ventricular contractile reserve (LVCR) based on force (systolic blood pressure/end-systolic volume). An additional non-imaging parameter based on EKG is the blunted heart rate reserve (HRR) which is a simple marker of altered autonomic balance and is associated with worse prognosis independently of ischemia.

Aim

To assess the relationship between HRR and LVCR in patients undergoing SE.

Methods

We enrolled 4707 patients (age 63.6±11.3 yrs, 2800 males) referred to SE for known or suspected coronary artery disease (CAD) and/or heart failure (HF) in 21 SE laboratories in 8 countries. The employed stress was exercise (n=2062), dipyridamole (n=2007) or dobutamine (n=638). We assessed LVCR (stress/rest ratio of force=systolic blood pressure/end-systolic volume, ESV). Stress-specific abnormal cutoff value of LVCR were <2.0 for exercise and dobutamine and <1.1 for dipyridamole. All readers had passed the upstream quality control reading for wall motion abnormalities and ESV. HR (with 12-lead ECG) was obtained each minute and recorded at rest and peak stress. HR reserve (HRR) was calculated as the peak/rest HR ratio.

Results

HRR was related to LVCR at cumulative (n=4707; r=0.351; p<0.001: see figure) and stress-specific analysis for exercise (r=0.351; p<0.001), dipyridamole (r=0.241; p<0.001) and dobutamine (r=0.214; p<0.001). At multivariate logistic regression analysis, blunted HRR (optimal cutoff: 1.73 for exercise, 1.306 for dipyridamole, 1.932 for dobutamine) was a significant predictor of abnormal LVCR at stress-specific analysis for exercise (Odds ratio = 0.285, 95% Confidence Intervals: 0.149–0.546, p=0.0001), dobutamine (Odds ratio = 0.187, 95% Confidence Intervals: 0.057–0.617, p=0.0001) and dipyridamole (Odds ratio = 0.263, 95% Confidence Intervals: 0.115–0.602, p=0.002).

Conclusion

A blunted HRR is a useful non-imaging predictor of abnormal LVCR response during exercise or pharmacological SE. HRR is a simple biomarker of autonomic unbalance of physiologic and potentially prognostic meaning. A “slow heart” during stress (with blunted HRR) is more often a “weak heart”, with blunted increase in force.

P1502Age- and gender-specific prognostic cutoff values of coronary flow velocity reserve in vasodilator stress echocardiography

Background

Coronary flow velocity reserve (CFVR) of left anterior descending artery is useful for risk stratification during stress echocardiography (SE) as an add-on to regional wall motion abnormalities (RWMA), but the age-and sex-dependence of prognostic cutoff values remains unclear.

Purpose

To provide sex and age-specific prognostic cut-off values which may be needed to account for the physiologic decline of CFVR with age, and sex-related differences in resting flow.

Methods

In an observational, prospective, multicenter, registry study design, we enrolled from August 2003 to August 2017 in 4 Italian cardiology referral centers with accredited, quality-controlled stress echo laboratory a consecutive sample of 5,577 patients (of them, 2,284 women and 110 aged ≥85 years) referred to the SE lab for known or suspected coronary artery disease, after exclusion of patients with inadequate acoustic window (n=295), premature test interruption (n=105), and lost to follow-up (n=173).All underwent dual imaging (RWMA and CFVR) dipyridamole SE (0.84 mg/kg over 6') and were followed-up. All-cause death and non-fatal myocardial infarction were the main outcome measures. Median follow-up of 20 months (1st quartile 8, 3rd quartile 43 months),

Results

There were 649 hard events (236 deaths and 413 non-fatal myocardial infarctions), 288 of which occurred in women and 38 in patients ≥85 years. With a ROC analysis, the best prognostic cut-off value for CFVR was almost the same for men (2.03) and women (2.02) and consistent across all age strata (<45 years: 2.03; 45–54 years: 2.04; 45–64 years: 2.03; 65–74 and 75–84 years: 2.0) except for the very elderly (>85 years) who showed an optimal value of 1.90. Independent prognostic indicators were RWMA (HR=5.42, 95% CI=2.42–12.15; p<0.0001) and reduced CFVR (HR=3.26, 95% CI 2.27–3.90; p<0.0001) in patients aged <85 years, and RWMA (HR=5.42, 95% CI=2.42–12.15; p<0.0001) in patients aged >85 years.

Best prognostic cut-off value of CFVR

Conclusion

A sex-independent cut-off value of CFVR ≤2.0 provides the optimal risk stratification across all age groups, except those >85 years in whom a lower cut-off <1.90 is needed. Risk stratification is more effective for all age groups when CFVR is combined with RWMA.

P4981The reduction of coronary flow velocity reserve in heart failure with reduced, mid-range or preserved ejection fraction

Background

Coronary microvascular disease has been described in heart failure (HF) in presence of angiographically normal epicardial coronary arteries. The prevalence of a reduction of coronary flow velocity reserve (CFVR) in different types of HF and its link with left ventricular contractile reserve (LVCR) is unclear.

Aim

To assess CFVR and LVCR in HF.

Methods

In a prospective, observational, multicenter study, we recruited 380 patients (234 male, 61%, age 66±11 years): 143 (38%) with HF and reduced (<40%) ejection fraction (HFrEF); 98 (26%) with HF and mid-range (40–50%) ejection fraction (HFmrEF); 139 (36%) patients with HF and preserved (>50%) ejection fraction (HFpEF). A control group of 52 asymptomatic patients (23 male, 44%, age 61±14 years) referred to testing for screening was also selected (Controls). All patients underwent dipyridamole (0.84 mg/kg) stress echocardiography in 12 accredited laboratories of 3 countries (Argentina, Brazil and Italy). CFVR was calculated as the stress/rest ratio of diastolic peak flow velocity pulsed-Doppler assessment of left anterior descending (LAD) artery flow. We assessed left ventricular contractile reserve (LVCR) based on global LV Force (systolic blood pressure/end-systolic volume).

Results

Reduced (≤2.0) CFVR was observed in 0/52 controls (0%); 25/139 HFpEF (18%); 28/98 HFmrEF (29%); 78/143 HFrEF (54%, p<0.001 vs all other groups). CFVR was highest in controls (2.80±0.57), lower in HFpEF (2.51±0.57) and HFmrEF (2.26±0.44), lowest in HFrEF (2.04±0.48, p<0.001 vs all other groups). The correlation with LVCR was absent in controls (r=0.098, p=0.491) and HFmrEF (r=0.032, p=0.756), present in HFrEF (r=0.375, p<0.001) and HFpEF (r=0.314, p<0.001).

LVCR vs CFVR

Conclusions

CFVR is frequently abnormal in all types of HF, although more frequently and more profoundly in HFrEF. CFVR mirrors contractile reserve in HFrEF and - less tightly - in HFpEF.

P4984The functional and coronary anatomic correlates of coronary flow velocity reserve during stress echocardiography

Background

The assessment of coronary flow velocity reserve (CFVR) on left anterior descending coronary artery (LAD) expands the risk stratification potential of stress echocardiography (SE) based on regional wall motion abnormalities (RWMA).

Aim

To assess the feasibility and functional correlates of CFVR.

Methods

In a prospective, observational, multicenter study, we initially screened 3,410 patients (2061, 60%, male; age 63±11 years; ejection fraction, EF=61±9%) with known or suspected coronary artery disease (CAD) and/or heart failure (HF). All patients underwent SE (exercise, n=1288; vasodilator, n=1860; dobutamine, n=262) based on RWMA in 20 accredited laboratories of 8 countries. CFVR was calculated as the stress/rest ratio of diastolic peak flow velocity pulsed-Doppler assessment of LAD flow. We also assessed B-lines (a sign of pulmonary congestion) with lung ultrasound and left ventricular contractile reserve (LVCR) based on Force (systolic blood pressure/end-systolic volume).

Results

The success rate for CFVR on LAD was 3,002/3,410 (feasibility=88%): 1,025/1,288 for exercise (80%), 1,766/1,860 (95%) for vasodilator (dipyridamole, n=1,841 and adenosine= 18) and 211/262 (81%) for dobutamine (p<0.001 vs vasodilator, p=NS vs exercise). Imaging time was <3 min and analysis time <1 min per patient. Reduced (≤2.0) CFVR was found in 896/3,002 (30%) patients. At multivariate logistic regression analysis, age (odds ratio, OR: 1.025, 95% Confidence intervals, CI: 1.015–1.036, p<0.001), diabetes (OR: 2.271, 95% CI: 1.218–4.235, p=0.10), RWMA (OR: 6.550, 95% CI: 4.989–8.599, p<0.01), abnormal LVCR (OR: 3.446, 95% CI: 2.774–4.281, p<0.01) and stress-rest B-lines change (OR: 1.519, 95% CI: 1.174–1.99, p=0.01) were associated with reduced CFVR. In the 1149 patients with coronary angiographic information, a reduced CFVR was present in 103/455 patients (23%) with no CAD, 119/432 (27%) with 1-, 72/167 (43%) with 2-, and 62/95 (65%) with 3-vessel disease (p<0.001 by ANOVA for trend).

Figure 1

Conclusions

CFVR is feasible with all SE protocols. The reduced CFVR is often accompanied by RWMA, abnormal LVCR and pulmonary congestion during stress.

[The Clinical use of Stress Echocardiography in Ischemic Heart Disease Cardiovascular Ultrasound (2017)15:7. Translation authors: Arystan A.Zh., Fettser D.V.]

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows detecting myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependence on operator expertise, the lack of outcome data (a widespread problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.