Background: Lung ultrasound detects pulmonary congestion as B-lines at rest, and more frequently, during exercise stress echocardiography (ESE). Methods: We performed ESE plus lung ultrasound (4-site simplified scan) in 4392 subjects referred for semi-supine bike ESE in 24 certified centers in 9 countries. B-line score ranged from 0 (normal) to 40 (severely abnormal). Five different populations were evaluated: control subjects (n=103); chronic coronary syndromes (n=3701); heart failure with reduced ejection fraction (n=395); heart failure with preserved ejection fraction (n=70); ischemic mitral regurgitation ≥ moderate at rest (n=123). In a subset of 2478 patients, follow-up information was available. Results: During ESE, B-lines increased in all study groups except controls. Age, hypertension, abnormal ejection fraction, peak wall motion score index, and abnormal heart rate reserve were associated with B-lines in multivariable regression analysis. Stress B lines (hazard ratio, 2.179 [95% CI, 1.015–4.680]; P =0.046) and ejection fraction <50% (hazard ratio, 2.942 [95% CI, 1.268–6.822]; P =0.012) were independent predictors of all-cause death (n=29 after a median follow-up of 29 months). Conclusions: B-lines identify the pulmonary congestion phenotype at rest, and more frequently, during ESE in ischemic and heart failure patients. Stress B-lines may help to refine risk stratification in these patients. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT 03049995.
Hemodynamic Heterogeneity of Reduced Cardiac Reserve Unmasked by Volumetric Exercise Echocardiography
Background: Two-dimensional volumetric exercise stress echocardiography (ESE) provides an integrated view of left ventricular (LV) preload reserve through end-diastolic volume (EDV) and LV contractile reserve (LVCR) through end-systolic volume (ESV) changes. Purpose: To assess the dependence of cardiac reserve upon LVCR, EDV, and heart rate (HR) during ESE. Methods: We prospectively performed semi-supine bicycle or treadmill ESE in 1344 patients (age 59.8 ± 11.4 years; ejection fraction = 63 ± 8%) referred for known or suspected coronary artery disease. All patients had negative ESE by wall motion criteria. EDV and ESV were measured by biplane Simpson rule with 2-dimensional echocardiography. Cardiac index reserve was identified by peak-rest value. LVCR was the stress-rest ratio of force (systolic blood pressure by cuff sphygmomanometer/ESV, abnormal values ≤2.0). Preload reserve was defined by an increase in EDV. Cardiac index was calculated as stroke volume index * HR (by EKG). HR reserve (stress/rest ratio) <1.85 identified chronotropic incompetence. Results: Of the 1344 patients, 448 were in the lowest tertile of cardiac index reserve with stress. Of them, 303 (67.6%) achieved HR reserve <1.85; 252 (56.3%) had an abnormal LVCR and 341 (76.1%) a reduction of preload reserve, with 446 patients (99.6%) showing ≥1 abnormality. At binary logistic regression analysis, reduced preload reserve (odds ratio [OR]: 5.610; 95% confidence intervals [CI]: 4.025 to 7.821), chronotropic incompetence (OR: 3.923, 95% CI: 2.915 to 5.279), and abnormal LVCR (OR: 1.579; 95% CI: 1.105 to 2.259) were independently associated with lowest tertile of cardiac index reserve at peak stress. Conclusions: Heart rate assessment and volumetric echocardiography during ESE identify the heterogeneity of hemodynamic phenotypes of impaired chronotropic, preload or LVCR underlying a reduced cardiac reserve.