Prognostic significance of myocardial energy expenditure and myocardial efficiency in patients with heart failure with reduced ejection fraction

The relationships between acetylcholine-induced chest pain, objective measures of coronary vascular function and symptom status

Background

Acetylcholine-induced chest pain is routinely measured during the assessment of microvascular function.

Aims

The aim was to determine the relationships between acetylcholine-induced chest pain and both symptom burden and objective measures of vascular function.

Methods

In patients with angina but no obstructive coronary artery disease, invasive studies determined the presence or absence of chest pain during both acetylcholine and adenosine infusion. Thermodilution-derived coronary blood flow (CBF) and index of microvascular resistance (IMR) was determined at rest and during both acetylcholine and adenosine infusion. Patients with epicardial spasm (>90%) were excluded; vasoconstriction between 20% and 90% was considered endothelial dysfunction.

Results

Eighty-seven patients met the inclusion criteria. Of these 52 patients (60%) experienced chest pain during acetylcholine while 35 (40%) did not. Those with acetylcholine-induced chest pain demonstrated: (1) Increased CBF at rest (1.6 ± 0.7 vs. 1.2 ± 0.4, p = 0.004) (2) Decreased IMR with acetylcholine (acetylcholine-IMR = 29.7 ± 16.3 vs. 40.4 ± 17.1, p = 0.004), (3) Equivalent IMR following adenosine (Adenosine-IMR: 21.1 ± 10.7 vs. 21.8 ± 8.2, p = 0.76), (4) Increased adenosine-induced chest pain (40/52 = 77% vs. 7/35 = 20%, p < 0.0001), (5) Increased chest pain during exercise testing (30/46 = 63% vs. 4/29 = 12%, p < 0.00001) with no differences in exercise duration or electrocardiographic changes, and (6) Increased prevalence of epicardial endothelial dysfunction (33/52 = 63% vs. 14/35 = 40%, p = 0.03).

Conclusions

After excluding epicardial spasm, acetylcholine-induced chest pain is associated with increased pain during exercise and adenosine infusion, increased coronary blood flow at rest, decreased microvascular resistance in response to acetylcholine and increased prevalence of epicardial endothelial dysfunction. These findings raise questions about the mechanisms underlying acetylcholine-induced chest pain.

Epicardial Adipose Tissue Assessed by Computed Tomography and Echocardiography Are Associated With Adverse Cardiovascular Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

Epicardial adipose tissue (EAT) has garnered attention as a prognostic and risk stratification factor for cardiovascular disease. This study, via meta-analyses, evaluates the associations between EAT and cardiovascular outcomes stratified across imaging modalities, ethnic groups, and study protocols.

METHODS

Medline and Embase databases were searched without date restriction on May 2022 for articles that examined EAT and cardiovascular outcomes. The inclusion criteria were (1) studies measuring EAT of adult patients at baseline and (2) reporting follow-up data on study outcomes of interest. The primary study outcome was major adverse cardiovascular events. Secondary study outcomes included cardiac death, myocardial infarction, coronary revascularization, and atrial fibrillation.

RESULTS

Twenty-nine articles published between 2012 and 2022, comprising 19 709 patients, were included in our analysis. Increased EAT thickness and volume were associated with higher risks of cardiac death (odds ratio, 2.53 [95% CI, 1.17-5.44]; P=0.020; n=4), myocardial infarction (odds ratio, 2.63 [95% CI, 1.39-4.96]; P=0.003; n=5), coronary revascularization (odds ratio, 2.99 [95% CI, 1.64-5.44]; P<0.001; n=5), and atrial fibrillation (adjusted odds ratio, 4.04 [95% CI, 3.06-5.32]; P<0.001; n=3). For 1 unit increment in the continuous measure of EAT, computed tomography volumetric quantification (adjusted hazard ratio, 1.74 [95% CI, 1.42-2.13]; P<0.001) and echocardiographic thickness quantification (adjusted hazard ratio, 1.20 [95% CI, 1.09-1.32]; P<0.001) conferred an increased risk of major adverse cardiovascular events.

CONCLUSIONS

The utility of EAT as an imaging biomarker for predicting and prognosticating cardiovascular disease is promising, with increased EAT thickness and volume being identified as independent predictors of major adverse cardiovascular events.

REGISTRATION

URL: https://www.crd.york.ac.uk/prospero; Unique identifier: CRD42022338075.

Impact of Myocardial Energy Expenditure and Diastolic Dysfunction on One Year Outcome Patients With HFpEF

Objective: To explore the correlation between characteristics of myocardial energy expenditure (MEE) and the degree of diastolic dysfunction in patients of heart failure with preserved ejection fraction (HFpEF) and its clinical significance.

Methods: 125 consecutive patients diagnosed with HFpEF in the Department of Cardiology, Affiliated Zhongshan Hospital of Dalian University from January 2018 to October 2018 were enrolled. According to the degree of diastolic dysfunction, patients were divided into group A (8 ≤ E/e' ≤15) and group B (E/e'&gt; 15), and MEE was calculated, patients finished 1-year clinical follow-up.

Results: The level of MEE in group A was significantly lower than that in group B (p &lt; 0.05). During 1-year follow up, MEE over 3145.69 kcal/systole was associated with increased risk of death as compared to patients with MEE less 3145.69 kcal/systole, and in patients with MEE over 101.68 kcal/min than in patients with MEE less than 101.68 kcal/min.

Conclusion: There is a significant correlation between MEE and diastolic dysfunction and MEE over 3145.69 kcal/systole as well as MEE over 101.68 kcal/min are linked with increased risk of 1-year mortality in HFpEF.

Concurrently Low Coronary Flow Reserve and Low Index of Microvascular Resistance Are Associated With Elevated Resting Coronary Flow in Patients With Chest Pain and Nonobstructive Coronary Arteries

BACKGROUND

Coronary microvascular function can be distinctly quantified using the coronary flow reserve (CFR) and index of microvascular resistance (IMR). Patients with low CFR can present with low or high IMR, although the prevalence and clinical characteristics of these patient groups remain unclear.

METHODS

One hundred ninety-nine patients underwent coronary microvascular assessments using coronary thermodilution techniques. A pressure-temperature sensor-tipped guidewire measured proximal and distal coronary pressure, whereas the inverse of the mean transit time to room temperature saline was used to measure coronary blood flow. The CFR and IMR were quantified during adenosine and acetylcholine hyperemia.

RESULTS

Low adenosine and acetylcholine CFR was observed in 70 and 49 patients, respectively, whereas low CFR/low IMR to adenosine and acetylcholine was observed in 39(56%) and 19(39%) patients, respectively. Despite similar adenosine CFR, patients with low CFR/low IMR had increased resting (2.8±1.2 versus 1.3±0.4s^-1) and hyperemic coronary blood flow (4.8±1.5 versus 2.1±0.5s^-1) compared with patients with low CFR/high IMR (both P<0.01). The same pattern was observed in response to acetylcholine. Patients with low CFR/low IMR to adenosine were younger (56±12 versus 63±10 years), women (84% versus 66%), had fewer coronary risk factors (1.1±1.0 versus 1.6±1.1), lower hemoglobin A1c (5.8±0.7 versus 6.1±0.9 mmol/L), and thinner septal thickness (8.5±2.5 versus 9.9±1.6 mm) compared with patients with low CFR/high IMR to adenosine (all P<0.05).

CONCLUSIONS

Low CFR/low IMR to adenosine and acetylcholine are associated with elevated resting coronary blood flow and preserved hyperemic coronary blood flow. These patients present with distinct phenotypic characteristics. Simultaneous CFR and IMR measures appear necessary to differentiate these endotypes.

Predicted Cardiac Functional Responses to Renal Actions of SGLT2i in the DAPACARD Trial Population: A Mathematical Modeling Analysis

Sodium-glucose cotransporter-2 inhibitors (SGLT2is) have been shown to reduce the risk of worsening heart failure (HF) in subjects with HF and a reduced ejection fraction (HFrEF) in multiple clinical trials. The DAPACARD clinical trial was conducted to examine the effects of DAPAgliflozin on CARDiac substrate uptake, myocardial efficiency, and myocardial contractile work in type 2 diabetes mellitus (T2DM) subjects. As a complement to the clinical study, a mechanistic mathematical model of cardiorenal physiology was used to quantify the influence of established natriuretic/diuretic effects of SGLT2i on cardiac function (myocardial efficiency and global longitudinal strain). Virtual participants reflecting the participant-level characteristics in the DAPACARD trial were produced by varying model parameters over physiologically plausible ranges. A second virtual population was generated by inducing a state of HFrEF in the DAPACARD T2DM virtual participants (DAPACARD-HFrEF virtual participants) for comparison. Cardiac responses to placebo and SGLT2i were simulated over 42 days. Cardiac hemodynamic improvements were predicted in DAPACARD-HFrEF virtual participants but not in DAPACARD virtual participants. In particular, the natriuresis/diuresis induced by SGLT2i improved the global longitudinal strain and myocardial efficiency in DAPACARD-HFrEF virtual participants within the first 14 days (change from baseline: global longitudinal strain: -0.95% and myocardial efficiency: 0.34%), whereas the global longitudinal strain and myocardial efficiency in DAPACARD virtual participants were slightly worse (change from baseline: global longitudinal strain: 0.35% and myocardial efficiency: -0.01%). The results of the DAPACARD virtual participants modeling were in line with the clinical data but do not preclude additional effects from other mechanisms of SGLT2i. This article is protected by copyright. All rights reserved.

Non-invasive CMR-Based Quantification of Myocardial Power and Efficiency Under Stress and Ischemic Conditions in Landrace Pigs

Background: Myocardial efficiency should be maintained stable under light-to-moderate stress conditions, but ischemia puts the myocardium at risk for impaired functionality. Additionally, the measurement of such efficiency typically requires invasive heart catheterization and exposure to ionizing radiation. In this work, we aimed to non-invasively assess myocardial power and the resulting efficiency during pharmacological stress testing and ischemia induction. Methods: In a cohort of n = 10 healthy Landrace pigs, dobutamine stress testing was performed, followed by verapamil-induced ischemia alongside cardiac magnetic resonance (CMR) imaging. External myocardial power, internal myocardial power, and myocardial efficiency were assessed non-invasively using geometrical and functional parameters from CMR volumetric as well as blood flow and pressure measurements. Results: External myocardial power significantly increased under dobutamine stress [2.3 (1.6-3.1) W/m² vs. 1.3 (1.1-1.6) W/m², p = 0.005] and significantly decreased under verapamil-induced ischemia [0.8 (0.5-0.9) W/m², p = 0.005]. Internal myocardial power [baseline: 5.9 (4.6-8.5) W/m²] was not affected by dobutamine [7.5 (6.9-9.0) W/m², p = 0.241] nor verapamil [5.8 (4.7-8.8) W/m², p = 0.878]. Myocardial efficiency did not change from baseline to dobutamine [21% (15-27) vs. 31% (20-44), p = 0.059] but decreased significantly during verapamil-induced ischemia [10% (8-13), p = 0.005]. Conclusion: In healthy Landrace pigs, dobutamine stress increased external myocardial power, whereas myocardial efficiency was maintained stable. On the contrary, verapamil-induced ischemia substantially decreased external myocardial power and myocardial efficiency. Non-invasive CMR was able to quantify these efficiency losses and might be useful for future clinical studies evaluating the effects of therapeutic interventions on myocardial energetics.

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

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.

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

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 (mVO₂). 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 mVO₂ 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 x-: 0.44, 95% CI: 0.39–0.49 for controls and adjusted x-: 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 mVO₂ 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.

Relationship between myocardial energy expenditure and postoperative ejection fraction in patients with severe mitral regurgitation

Objective:

This prospective study aimed to investigate the myocardial energy metabolism in severe mitral regurgitation (MR) and explore its effect on postoperative differentiation of ejection fraction (EF).

Methods:

A total of 85 patients with severe MR were prospectively enrolled from October 2018 to June 2019. During the study period, a total of 50 patients underwent mitral valve surgery and 49 patients were finally enrolled due to 1 missing data. Left ventricular function, circumferential end-systolic stress (cESS), and myocardial energy expenditure (MEE) were measured by transthoracic echocardiography preoperatively and 3 months after surgery. Patients were divided into 2 groups according to absolute difference of postoperative differentiation of EF.

Results:

Nine patients underwent mitral valve repair and 40 underwent prosthetic valve replacement. Patients with reduced EF had higher MEE demonstrated with cESS and MEE. Negative correlation between preoperative EF and N-terminal pro-brain natriuretic peptide (NT-proBNP), cESS, MEEs, and MEEm and positive correlation between preoperative EF and effective regurgitant orifice area were found. Complications occurred in 12 patients during hospitalization. Basal NT-proBNP, left atrium (LA), and cESS were significantly higher in postoperatively decreased EF group. Taking into consideration the covariates of multiple logistic regression analysis, LA and cESS were found to be independent predictors of EF reduction postoperatively.

Conclusion:

Higher LA and cESS are independent predictors of postoperative EF reduction. Preoperative high end-systolic stress could predict postoperative EF reduction and hence could be helpful for determining the timing of mitral valve surgery. Although MEE was higher in postoperatively decreased EF group, it did not reach statistical significance.

Resting Cardiac Efficiency Affects Survival Following Transcatheter Aortic Valve Replacement

OBJECTIVE

Cardiac power to left ventricular mass (LVM) ratio, also termed cardiac efficiency (CE), reflects the rate of cardiac work delivered to the potential energy stored in LVM. We sought to assess the association between baseline resting CE and survival post transcatheter aortic valve replacement (TAVR).

METHODS

We retrospectively extracted data of patients who received TAVR in the Mayo Clinic Foundation with follow up data available at 1 year. Cardiac output was measured using Doppler echocardiography at baseline. CE was calculated using the formula, (cardiac output × mean arterial blood pressure)/(451 × LVM × 100) W/100 g. Survival score analysis was performed to identify cut off value for CE to identify the maximum difference in mortality in the study cohort. Patients were subsequently divided into 2 groups CE < 0.38 W/100 g and CE ≥ 0.38 W/100 g. Survival was determined using Kaplan-Meier method.

RESULTS

We included 954 patients in the final analysis. CE in group1 vs group 2 was 0.31 ± 0.05 W/100 g vs 0.59 ± 0.18 W/100 g. Patients in group1 were more likely to be male, had a higher prevalence of atrial fibrillation, prior myocardial infarction, mitral and tricuspid regurgitation. They also had a higher STS risk score, NYHA functional class, and lower aortic valve area. The remainder of the baseline characteristics was similar in both groups. A lower CE was associated with higher 1-year mortality following TAVR based on multivariate analysis. (Group1: 22.18% vs Group 2: 9.89%, p < .0001).

CONCLUSION

In our cohort, a low baseline CE (<0.38 W/100 g) conferred higher mortality risk following TAVR.