Increased pulmonary blood volume variation in patients with heart failure compared to healthy controls: a noninvasive, quantitative measure of heart failure

Abstract

Variation of the blood content of the pulmonary vascular bed during a heartbeat can be quantified by pulmonary blood volume variation (PBVV) using magnetic resonance imaging (MRI). The aim was to evaluate whether PBVV differs in patients with heart failure compared with healthy controls and investigate the mechanisms behind the PBVV. Forty-six patients and 10 controls underwent MRI. PBVV was calculated from blood flow measurements in the main pulmonary artery and a pulmonary vein, defined as the maximum difference in cumulative PBV over one heartbeat. PBVV was indexed to stroke volume (SV) in the main pulmonary artery (PBVVSV). Patients displayed higher PBVVSV than controls (58 ± 14 vs. 43 ± 7%, P < 0.001). The change in PBVVSV could be explained by left ventricular (LV) longitudinal contribution to SV ( R2 = 0.15, P = 0.02) and the phase shift between in- and outflow ( R2 = 0.31, P < 0.001) in patients. Both variables contributed to the multiple regression analysis model and predicted PBVVSV ( R2 = 0.38); however, the phase shift alone explained ~30% of the variation in PBVVSV. No correlation was found between PBVVSV and large vessel area. In conclusion, PBVVSV was higher in patients compared with controls. Approximately 40% of the variation of PBVVSV in patients can be explained by the LV longitudinal contribution to SV and the phase shift between pulmonary in- and outflow, where the phase shift alone accounts for ~30%. The remaining variation (60–70%) most likely occurs on a small vessel level. Future studies are needed to show the clinical added value of PBVVSV compared with right-heart catheterization. NEW & NOTEWORTHY This study shows that the pulmonary blood volume variation indexed to the stroke volume is higher in patients with heart failure compared with controls. The mechanisms behind this are lack of systolic suction from the left ventricular atrioventricular plane descent and increased phase shift between the in- and outflow to the pulmonary circulation (~40%), where the phase shift alone accounts for ~30%. The remaining variation (60–70%) is suggested to occur on a small vessel level.

Ventricular longitudinal shortening is an independent predictor of death in heart failure patients with reduced ejection fraction

“…The systolic movement of the mitral and tricuspid valves towards the apex ejects blood into the great arteries while simultaneously causing suction of blood into the atria 37 . This was corroborated by a recent CMR study measuring flow profiles in the pulmonary veins in both controls and heart failure patients 38 .…”

Left atrial conduit function: A short review

“…Less obvious, however, is that such an augmented conduit contribution may also be found in a totally opposite scenario, with conduit progressively contributing to filling volume during intensive exercise in competitive athletes (Wright et al, 2015). This is compatible with a U‐shaped behavior for this parameter across the spectrum (Figure 1, left), from a markedly diseased condition, like end‐stage HF, to a “supranormal” situation, like the one depicted in athletes, similarly to what happens for other functional imaging parameters (Al‐Mashat et al, 2020). In the “supranormal” scenario, in fact, conduit would track the apex‐to‐base intracavitary pressure gradient existing, in early diastole, within the single chamber formed by the atrium and the ventricle, when the mitral valve is open (Courtois et al, 1988).…”

Impact of Semi-Fowler's Position in Chronic Heart Failure (CHF) Patients: Scoping Review

“…The lower position affect vessel distenstion and vascular resistance especially on lateral lying position (David J Marlin & Thea L Vincent, 2007). Futhermore, interleration pulmonary blood flow and cardiac cycle measured by PBVV (Pulmonary blood volume variation) (Al-Mashat et al, 2020).…”