Changes in the Inferior Vena Cava Are More Sensitive Than Venous Pressure During Fluid Removal: A Proof-of-Concept Study.

BACKGROUND: Congestion is central to the pathophysiology of heart failure (HF); thus, tracking congestion is crucial for the management of patients with HF. In this study we aimed to compare changes in inferior vena cava diameter (IVCD) with venous pressure following manipulation of volume status during ultrafiltration in patients with cardiac dysfunction. METHODS AND RESULTS: Patients with stable hemodialysis and with systolic or diastolic dysfunction were studied. Central venous pressure (CVP) and peripheral venous pressure (PVP) were measured before and after hemodialysis. IVCD and PVP were measured simultaneously just before dialysis, 3 times during dialysis and immediately after dialysis. Changes in IVCD and PVP were compared at each timepoint with ultrafiltration volumes. We analyzed 30 hemodialysis sessions from 20 patients. PVP was validated as a surrogate for CVP. Mean ultrafiltration volume was 2102 ± 667 mL. IVCD discriminated better ultrafiltration volumes ≤ 500 mL or ≤ 750 mL than PVP (AUC 0.80 vs 0.62, and 0.80 vs 0.56, respectively; both P< 0.01). IVCD appeared to track better ultrafiltration volume (P< 0.01) and hemoconcentration (P< 0.05) than PVP. Changes in IVCD were of greater magnitude than those of PVP (average change from predialysis: -58 ± 30% vs -28 ± 21%; P< 0.001). CONCLUSIONS: In patients undergoing ultrafiltration, changes in IVCD tracked changes in volume status better than venous pressure.

Noninvasive measurement of cardiac performance in recovery from exercise in heart failure patients.

OBJECTIVE: To examine the association between cardiac performance during recovery and the severity of heart failure, as determined by clinical and cardiopulmonary exercise test responses. METHODS: As part of a retrospective cohort study, 46 heart failure patients and 13 normal subjects underwent cardiopulmonary exercise testing while cardiac output was measured using a noninvasive device. Cardiac output in recovery was expressed as the slope of a single exponential relationship between cardiac output and time; the recovery-time constant was assessed in relation to indices of cardiac function, along with clinical, functional, and cardiopulmonary exercise responses. RESULTS: The recovery time constant was delayed in patients with heart failure compared with normal subjects (296.7 ± 238 vs. 110.1 ±27 seconds, p <0.01), and the slope of the decline of cardiac output in recovery was steeper in normal subjects compared with heart failure patients (p<0.001). The slope of the decline in cardiac output recovery was inversely related to peak VO(2) (r = -0.72, p<0.001) and directly related to the VE/VCO(2) slope (r = 0.57, p,0.001). Heart failure patients with abnormal recovery time constants had lower peak VO(2), lower VO(2) at the ventilatory threshold, lower peak cardiac output, and a heightened VE/VCO(2) slope during exercise. CONCLUSIONS: Impaired cardiac output recovery kinetics can identify heart failure patients with more severe disease, lower exercise capacity, and inefficient ventilation. Estimating cardiac output in recovery from exercise may provide added insight into the cardiovascular status of patients with heart failure.

Noninvasive measurement of cardiac performance in recovery from exercise in heart failure patients

OBJECTIVE: To examine the association between cardiac performance during recovery and the severity of heart failure, as determined by clinical and cardiopulmonary exercise test responses. METHODS: As part of a retrospective cohort study, 46 heart failure patients and 13 normal subjects underwent cardiopulmonary exercise testing while cardiac output was measured using a noninvasive device. Cardiac output in recovery was expressed as the slope of a single exponential relationship between cardiac output and time; the recovery-time constant was assessed in relation to indices of cardiac function, along with clinical, functional, and cardiopulmonary exercise responses. RESULTS: The recovery time constant was delayed in patients with heart failure compared with normal subjects (296.7 + 238 vs. 110.1 +27 seconds, p <0.01), and the slope of the decline of cardiac output in recovery was steeper in normal subjects compared with heart failure patients (p,0.001). The slope of the decline in cardiac output recovery was inversely related to peak VO2 (r = -0.72, p<0.001) and directly related to the VE/VCO2 slope (r = 0.57, p,0.001). Heart failure patients with abnormal recovery time constants had lower peak VO2, lower VO2 at the ventilatory threshold, lower peak cardiac output, and a heightened VE/VCO2 slope during exercise. CONCLUSIONS: Impaired cardiac output recovery kinetics can identify heart failure patients with more severe disease, lower exercise capacity, and inefficient ventilation. Estimating cardiac output in recovery from exercise may provide added insight into the cardiovascular status of patients with heart failure.