Surrogates for myocardial power and power efficiency in patients with aortic valve disease

Aruğaslan

et al. 2020

J Cardiovasc Imaging

BACKGROUND It is difficult to determine left ventricular systolic performance in patients with severe mitral regurgitation (MR) since left ventricular ejection fraction (EF) could be preserved until the end stages of the disease. Myocardial efficiency (MEf) describes the amount of external work (EW) done by the left ventricle per unit of oxygen consumed (mVO 2 ). In the present study, we aimed to investigate MEf in patients with asymptomatic severe MR using a novel echocardiographic method. METHODS A total of 27 patients with severe asymptomatic MR and 26 healthy volunteers were included in this cross-sectional study. EW was measured using stroke volume and blood pressure, while mVO 2 was estimated using double product and left ventricular mass. RESULTS There were no differences between the groups with regards to EF (66% ± 5% vs. 69% ± 7%), while MEf was significantly reduced in patients with severe MR (25% ± 11% vs. 44% ± 12%, p < 0.001). This difference was maintained even after adjustment for age, gender and body surface area (adjusted : 0.44, 95% CI: 0.39–0.49 for controls and adjusted : 0.24, 95% CI: 0.19–0.29 for patients with severe MR). Further analysis showed that this reduction was due to an increase in total mVO 2 in the severe MR group. MEf of thepatients who were both on β-blockers and angiotensin converting enzyme inhibitors/angiotensin receptor blockers were higher than those who were not on any drugs, but this difference was not statistically significant (32% ± 15% vs. 23% ± 9%, p = 0.41). CONCLUSIONS MEf was significantly lower in patients with asymptomatic severe MR and preserved EF.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

An Analysis of Myocardial Efficiency in Patients with Severe Asymptomatic Mitral Regurgitation

Aruğaslan

et al. 2020

J Cardiovasc Imaging

Journal of Cardiovascular Magnetic Resonance

“…The temporal solution was 25 timesteps for 4D flow measurements and 30 timesteps for 2D flow measurements. We could show that 4D flow measurements with 25 timesteps are a feasible alternative to flow measurements with higher temporal solution in a prior study [ 15 ].…”

Section: Methodsmentioning

confidence: 99%

“…The ratio of the power needed to pump a given blood volume against a given afterload (circulatory power, CP) to the power used by the heart to perform one heartbeat (Left ventricular myocardial power, LVMP) is described as circulatory efficiency (CircE). LVMP was defined as the surrogate power of the LV to perform one heartbeat since the applied method is an estimation [ 15 , 19 ]: …”

Section: Methodsmentioning

confidence: 99%

“…A reduced surrogate marker of circulatory efficiency in patients with different stages of AS has been found using a recent noninvasive and radiation-free CMR method [ 15 ]. In the present study, we aimed to apply this novel noninvasive method to assess surrogate markers of circulatory efficiency and power in a cohort of 41 patients with severe AS before and after surgical AVR and in 10 age and sex-matched controls.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Circulatory efficiency in patients with severe aortic valve stenosis before and after aortic valve replacement

Nordmeyer

Lee

Goubergrits

et al. 2021

Background Circulatory efficiency reflects the ratio between total left ventricular work and the work required for maintaining cardiovascular circulation. The effect of severe aortic valve stenosis (AS) and aortic valve replacement (AVR) on left ventricular/circulatory mechanical power and efficiency is not yet fully understood. We aimed to quantify left ventricular (LV) efficiency in patients with severe AS before and after surgical AVR. Methods Circulatory efficiency was computed from cardiovascular magnetic resonance (CMR) imaging derived volumetric data, echocardiographic and clinical data in patients with severe AS (n = 41) before and 4 months after AVR and in age and sex-matched healthy subjects (n = 10). Results In patients with AS circulatory efficiency was significantly decreased compared to healthy subjects (9 ± 3% vs 12 ± 2%; p = 0.004). There were significant negative correlations between circulatory efficiency and LV myocardial mass (r = − 0.591, p < 0.001), myocardial fibrosis volume (r = − 0.427, p = 0.015), end systolic volume (r = − 0.609, p < 0.001) and NT-proBNP (r = − 0.444, p = 0.009) and significant positive correlation between circulatory efficiency and LV ejection fraction (r = 0.704, p < 0.001). After AVR, circulatory efficiency increased significantly in the total cohort (9 ± 3 vs 13 ± 5%; p < 0.001). However, in 10/41 (24%) patients, circulatory efficiency remained below 10% after AVR and, thus, did not restore to normal values. These patients also showed less reduction in myocardial fibrosis volume compared to patients with restored circulatory efficiency after AVR. Conclusion In our cohort, circulatory efficiency is reduced in patients with severe AS. In 76% of cases, AVR leads to normalization of circulatory efficiency. However, in 24% of patients, circulatory efficiency remained below normal values even after successful AVR. In these patients also less regression of myocardial fibrosis volume was seen. Trial Registration clinicaltrials.gov NCT03172338, June 1, 2017, retrospectively registered.

Pulsatile energy consumption as a surrogate marker for vascular afterload improves with time post transcatheter aortic valve replacement in patients with aortic stenosis

et al. 2022

The effect of arterial stiffening on elevated pulsatile left ventricular afterload patients with aortic stenosis (AS) is pronounced beyond systemic hypertension. Circulatory afterload pulsatile efficiency (CAPE) is a marker of vascular function, defined as the ratio of steady state energy consumption (SEC) to maintain systemic circulation and pulsatile energy consumption (PEC). Twenty patients aged 80 ± 7 years were assessed at baseline and a median of 60 days post transcatheter aortic valve replacement (TAVR), with pulsatile vascular load calculated using simultaneous radial applanation tonometry derived aortic pressure and cardiac magnetic resonance phase-contrast imaging derived ascending aortic flow. Eight out of 20 patients had a reduction in PEC post TAVR, and the reduction of PEC correlated strongly with the number of days post TAVR ( R = 0.62, P < 0.01). Patients assessed within the 100 days of TAVR had a rise in their PEC when compared to baseline (0.19 ± 0.09 vs 0.14 ± 0.08 W, P = 0.04). Baseline PEC correlated moderately with baseline SEC ( R = 0.49, P = 0.03), and a high baseline PEC was predictive of post TAVR PEC reduction ( R = 0.54, P =0.01). Overall, no significant differences were found between baseline and post TAVR for systolic aortic pressure (131 ± 20 vs 131 ± 20 mmHg), systemic vascular resistance (1894 ± 493 vs 2015 ± 519 dynes.s/cm 5 ), aortic valve ejection time (337 ± 22 vs 324 ± 34 ms) or aortic characteristic impedance (120 ± 48 vs 107 ± 41 dynes.s/cm 5 ). Improved flow profiles after TAVR likely unmask the true vascular properties by altering ventriculo-valvulo-arterial coupling, leading to downstream vascular remodelling secondary to flow conditioning, and results in eventual improvement of pulsatile afterload as reflected by our proposed index of CAPE.