bims-hafaim 2023-05-21 papers

Issue of 2023–05–21
three papers selected by
Kyle McCommis, Saint Louis University

Circulation. 2023 May 18.

Retained Metabolic Flexibility of the Failing Human Heart.

William D Watson, Peregrine G Green, Andrew J M Lewis, Per Arvidsson, Giovanni Luigi De Maria, Hakan Arheden, Einar Heiberg, William T Clarke, Christopher T Rodgers, Ladislav Valkovič, Stefan Neubauer, Neil Herring, Oliver J Rider.

BACKGROUND: The failing heart is traditionally described as metabolically inflexible and oxygen starved, causing energetic deficit and contractile dysfunction. Current metabolic modulator therapies aim to increase glucose oxidation by increasing oxygen efficiency of adenosine triphosphate production, with mixed results.
METHODS: To investigate metabolic flexibility and oxygen delivery in the failing heart, 20 patients with nonischemic heart failure with reduced ejection fraction (left ventricular ejection fraction 34.9±9.1) underwent separate infusions of insulin+glucose infusion (I+G) or Intralipid infusion. We used cardiovascular magnetic resonance to assess cardiac function and measured energetics using phosphorus-31 magnetic resonance spectroscopy. To investigate the effects of these infusions on cardiac substrate use, function, and myocardial oxygen uptake (MVo2), invasive arteriovenous sampling and pressure-volume loops were performed (n=9).
RESULTS: At rest, we found that the heart had considerable metabolic flexibility. During I+G, cardiac glucose uptake and oxidation were predominant (70±14% total energy substrate for adenosine triphosphate production versus 17±16% for Intralipid; P=0.002); however, no change in cardiac function was seen relative to basal conditions. In contrast, during Intralipid infusion, cardiac long-chain fatty acid (LCFA) delivery, uptake, LCFA acylcarnitine production, and fatty acid oxidation were all increased (LCFA 73±17% of total substrate versus 19±26% total during I+G; P=0.009).Myocardial energetics were better with Intralipid compared with I+G (phosphocreatine/adenosine triphosphate 1.86±0.25 versus 2.01±0.33; P=0.02), and systolic and diastolic function were improved (LVEF 34.9±9.1 baseline, 33.7±8.2 I+G, 39.9±9.3 Intralipid; P<0.001). During increased cardiac workload, LCFA uptake and oxidation were again increased during both infusions. There was no evidence of systolic dysfunction or lactate efflux at 65% maximal heart rate, suggesting that a metabolic switch to fat did not cause clinically meaningful ischemic metabolism.
CONCLUSIONS: Our findings show that even in nonischemic heart failure with reduced ejection fraction with severely impaired systolic function, significant cardiac metabolic flexibility is retained, including the ability to alter substrate use to match both arterial supply and changes in workload. Increasing LCFA uptake and oxidation is associated with improved myocardial energetics and contractility. Together, these findings challenge aspects of the rationale underlying existing metabolic therapies for heart failure and suggest that strategies promoting fatty acid oxidation may form the basis for future therapies.

Keywords: adenosine triphosphate; heart failure; magnetic resonance spectroscopy; metabolism

DOI: https://doi.org/10.1161/CIRCULATIONAHA.122.062166

Circ Heart Fail. 2023 May 19. e009837

Dapagliflozin Improves Heart Failure Symptoms and Physical Limitations Across the Full Range of Ejection Fraction: Pooled Patient-Level Analysis From DEFINE-HF and PRESERVED-HF Trials.

Michael E Nassif, Sheryl L Windsor, Kensey Gosch, Barry A Borlaug, Mansoor Husain, Silvio E Inzucchi, Dalane W Kitzman, Darren K McGuire, Bertram Pitt, Benjamin M Scirica, Sanjiv J Shah, Guillermo Umpierrez, Bethany A Austin, Sumant Lamba, Taiyeb Khumri, Kavita Sharma, Mikhail N Kosiborod.

BACKGROUND: Patients with heart failure (HF) have a high burden of symptoms and physical limitations, regardless of ejection fraction (EF). Whether the benefits of SGLT2 (sodium-glucose cotransporter-2) inhibitors on these outcomes vary across the full range of EF remains unclear.
METHODS: Patient-level data were pooled from the DEFINE-HF trial (Dapagliflozin Effects on Biomarkers, Symptoms, and Functional Status in Patients With Heart Failure With Reduced Ejection Fraction) of 263 participants with reduced EF (≤40%), and PRESERVED-HF trial (Effects of Dapagliflozin on Biomarkers, Symptoms and Functional Status in Patients With Preserved Ejection Fraction Heart Failure) of 324 participants with preserved EF (≥45%). Both were randomized, double-blind 12-week trials of dapagliflozin versus placebo, recruiting participants with New York Heart Association class II or higher and elevated natriuretic peptides. The effect of dapagliflozin on the change in the Kansas City Cardiomyopathy Questionnaire (KCCQ) Clinical Summary Score (CSS) at 12 weeks was tested with ANCOVA adjusted for sex, baseline KCCQ, EF, atrial fibrillation, estimated glomerular filtration rate, and type 2 diabetes. Interaction of dapagliflozin effects on KCCQ-CSS by EF was assessed using EF both categorically and continuously with restricted cubic spline. Responder analyses, examining proportions of patients with deterioration, and clinically meaningful improvements in KCCQ-CSS were conducted using logistic regression.
RESULTS: Of 587 patients randomized (293 dapagliflozin, 294 placebo), EF was ≤40, >40-≤60, and >60% in 262 (45%), 199 (34%), and 126 (21%), respectively. Dapagliflozin improved KCCQ-CSS at 12 weeks (placebo-adjusted difference 5.0 points [95% CI, 2.6-7.5]; P<0.001). This was consistent in participants with EF≤40 (4.6 points [95% CI, 1.0-8.1]; P=0.01), >40 to ≤60 (4.9 points [95% CI, 0.8-9.0]; P=0.02) and >60% (6.8 points [95% CI, 1.5-12.1]; P=0.01; Pinteraction=0.79). Benefits of dapagliflozin on KCCQ-CSS were also consistent when analyzing EF continuously (Pinteraction=0.94). In responder analyses, fewer dapagliflozin-treated patients had deterioration and more had small, moderate, and large KCCQ-CSS improvements versus placebo; these results were also consistent regardless of EF (all Pinteractionvalues nonsignificant).
CONCLUSIONS: In patients with HF, dapagliflozin significantly improves symptoms and physical limitations after 12 weeks of treatment, with consistent and clinically meaningful benefits across the full range of EF.
REGISTRATION: URL: https://www.
CLINICALTRIALS: gov; Unique identifiers: NCT02653482 and NCT03030235.

Keywords: Kansas City Cardiomyopathy Questionnaire; SGLT2 inhibitors; dapagliflozin; ejection fraction; health status; heart failure; quality of life

DOI: https://doi.org/10.1161/CIRCHEARTFAILURE.122.009837

J Am Heart Assoc. 2023 05 16. 12(10): e026950

Progressive Cardiac Metabolic Defects Accompany Diastolic and Severe Systolic Dysfunction in Spontaneously Hypertensive Rat Hearts.

Jie Li, Krzysztof Minczuk, Qiao Huang, Brandon A Kemp, Nancy L Howell, Mahendra D Chordia, R Jack Roy, James T Patrie, Zoraiz Qureshi, Christopher M Kramer, Frederick H Epstein, Robert M Carey, Bijoy K Kundu, Susanna R Keller.

Background Cardiac metabolic abnormalities are present in heart failure. Few studies have followed metabolic changes accompanying diastolic and systolic heart failure in the same model. We examined metabolic changes during the development of diastolic and severe systolic dysfunction in spontaneously hypertensive rats (SHR). Methods and Results We serially measured myocardial glucose uptake rates with dynamic 2-[18F] fluoro-2-deoxy-d-glucose positron emission tomography in vivo in 9-, 12-, and 18-month-old SHR and Wistar Kyoto rats. Cardiac magnetic resonance imaging determined systolic function (ejection fraction) and diastolic function (isovolumetric relaxation time) and left ventricular mass in the same rats. Cardiac metabolomics was performed at 12 and 18 months in separate rats. At 12 months, SHR hearts, compared with Wistar Kyoto hearts, demonstrated increased isovolumetric relaxation time and slightly reduced ejection fraction indicating diastolic and mild systolic dysfunction, respectively, and higher (versus 9-month-old SHR decreasing) 2-[18F] fluoro-2-deoxy-d-glucose uptake rates (Ki). At 18 months, only few SHR hearts maintained similar abnormalities as 12-month-old SHR, while most exhibited severe systolic dysfunction, worsening diastolic function, and markedly reduced 2-[18F] fluoro-2-deoxy-d-glucose uptake rates. Left ventricular mass normalized to body weight was elevated in SHR, more pronounced with severe systolic dysfunction. Cardiac metabolite changes differed between SHR hearts at 12 and 18 months, indicating progressive defects in fatty acid, glucose, branched chain amino acid, and ketone body metabolism. Conclusions Diastolic and severe systolic dysfunction in SHR are associated with decreasing cardiac glucose uptake, and progressive abnormalities in metabolite profiles. Whether and which metabolic changes trigger progressive heart failure needs to be established.

Keywords: cardiac magnetic resonance imaging; diastolic and systolic function; dynamic FDG PET; left ventricular hypertrophy; myocardial metabolism; spontaneously hypertensive rats

DOI: https://doi.org/10.1161/JAHA.122.026950