Abnormal Glucose Tolerance Is Associated with a Reduced Myocardial Metabolic Flexibility in Patients with Dilated Cardiomyopathy

Impact of type 2 diabetes mellitus on left ventricular deformation in non-ischemic dilated cardiomyopathy patients assessed by cardiac magnetic resonance imaging

Background

Type 2 diabetes mellitus (T2DM) increases the risk of worse long-term outcomes in patients with non-ischemic dilated cardiomyopathy (NIDCM). However, the additive effects of T2DM on left ventricular (LV) function in NIDCM remain unclear. Accordingly, we aimed to investigate the impact of comorbid T2DM on LV deformation in NIDCM individuals.

Materials and methods

Three hundred forty-two NIDCM patients without T2DM [NIDCM (T2DM−)], 93 with T2DM [NIDCM (T2DM+)] and 80 age- and sex-matched normal controls who underwent cardiac magnetic resonance scanning were included. LV geometry, function, and LV global strains, including peak strain (PS), peak systolic strain rate (PSSR) and peak diastolic strain rate (PDSR) in the radial, circumferential and longitudinal directions, were measured. NIDCM (T2DM+) patients were divided into two subgroups based on the HbA1c level (< 7.0% and ≥ 7.0%). The determinants of reduced LV myocardial strain for all NIDCM individuals and NIDCM (T2DM+) patients were assessed using multivariable linear regression analyses.

Results

Compared with normal controls, both NIDCM (T2DM −) and NIDCM (T2DM+) patients exhibited increased LV end-diastolic and end-systolic volume index and decreased LV ejection fraction. LV global strains progressively declined from the normal controls to the NIDCM (T2DM−) group to the NIDCM (T2DM+) group (all p < 0.017), except for radial PDSR and PSSR. Subgroup analysis showed that LV global radial PS and longitudinal PS, PSSR-L and PDSR-L were worse in NIDCM patients with poor glycemic control than in those with good glycemic control (p < 0.017). T2DM was an independent determinant of reduced LV global circumferential PS and longitudinal PS in patients with NIDCM (both p < 0.05). An increased HbA1c level was independently associated with a decreased global radial PS (β = − 0.285, p < 0.01) and longitudinal PS (β = 0.320, p < 0.01) in NIDCM (T2DM+) patients.

Conclusions

T2DM has an additive deleterious effect on LV systolic and diastolic function in NIDCM patients. Among NIDCM patients with T2DM, HbA1c was found to be associated with reduced LV myocardial strain.

Use of cardiac magnetic resonance to detect changes in metabolism in heart failure

The heart has a massive adenosine triphosphate (ATP) requirement, produced from the oxidation of metabolic substrates such as fat and glucose. Magnetic resonance spectroscopy offers a unique opportunity to probe this biochemistry: ³¹Phosphorus spectroscopy can demonstrate the production of ATP and quantify levels of the transport molecule phosphocreatine while 13Carbon spectroscopy can demonstrate the metabolic fates of glucose in real time. These techniques allow the metabolic deficits in heart failure to be interrogated and can be a potential future clinical tool.

Impact of diabetes mellitus on left ventricular longitudinal function of patients with non-ischemic dilated cardiomyopathy

Background

Left ventricular (LV) longitudinal dysfunction has been identified in type 2 diabetes mellitus (T2DM) patients with preserved LV ejection fraction (LVEF). However, the impact of T2DM on LV longitudinal function or the association of LV longitudinal function with outcome for dilated cardiomyopathy (DCM) remains unclear.

Methods

We retrospectively studied 206 patients with non-ischemic DCM, mean age of 59 ± 17 years and LVEF of 31 ± 8% (all < 45%). All patients underwent a standard echocardiographic examination, and LV longitudinal function was assessed in terms of global longitudinal strain (GLS). Long-term outcomes were assessed, with a median follow-up period of 6.2 years, as primary endpoints of death from or hospitalization for deteriorating heart failure.

Results

GLS of DCM patients with T2DM (n = 55) was significantly lower than that in DCM patients without T2DM (n = 151) in spite of similar conventional LV function (7.0 ± 2.0% vs. 7.8 ± 2.2%, p = 0.03). Kaplan–Meier curves indicated that long-term outcomes for DCM patients without T2DM were better than for those with T2DM (log-rank p = 0.001). Subdividing the two groups into four with by using the median value of GLS (7.9%) showed long-term outcome was worst for DCM patients with T2DM and low GLS. Cox proportional hazards analyses demonstrated an independent association of T2DM, GLS and left atrial volume index with long-term outcome. Moreover, multiple regression analysis for the association of GLS showed that T2DM was the independent determinant parameter for GLS as well as for LVEF and left atrial volume index.

Conclusion

Management of DCM patients with T2DM may be improved by using GLS guidance.

Admission Hyperglycemia as a Predictor of Mortality in Acute Heart Failure: Comparison between the Diabetics and Non-Diabetics

Background: To investigate the impact of admission hyperglycemia (HGL) on in-hospital death (IHD) and 1-year mortality in acute heart failure (AHF) patients with or without diabetes mellitus (DM). Methods: Among 5625 AHF patients enrolled in a nationwide registry, 5541 patients were divided into four groups based on the presence of admission HGL and diabetes mellitus (DM). Admission HGL was defined as admission glucose level > 200 mg/dL. IHD and 1-year mortality were compared. Results: IHD developed in 269 patients (4.9%), and 1-year death developed in 1220 patients (22.2%). DM was a significant predictor of 1-year death (24.8% in DM vs. 20.5% in non-DM, p < 0.001), but not for IHD. Interestingly, admission HGL was a significant predictor of both IHD (7.6% vs. 4.2%, p < 0.001) and 1-year death (26.2% vs. 21.3%, p = 0.001). Admission HGL was a significant predictor of IHD in both DM and non-DM group, whereas admission HGL was a significant predictor of 1-year death only in non-DM (27.8% vs. 19.9%, p = 0.003), but not in DM group. In multivariate analysis, admission HGL was an independent predictor of 1-year mortality in non-DM patients (HR 1.32, 95% CI 1.03–1.69, p = 0.030). Conclusion: Admission HGL was a significant predictor of IHD and 1-year death in patients with AHF, whereas DM was only a predictor of 1-year death. Admission HGL was an independent predictor of 1-year mortality in non-DM patients with AHF, but not in DM patients. Careful monitoring and intensive medical therapy should be considered in AHF patients with admission HGL, regardless of DM.

Triheptanoin versus trioctanoin for long-chain fatty acid oxidation disorders: a double blinded, randomized controlled trial

BACKGROUND

Observational reports suggest that supplementation that increases citric acid cycle intermediates via anaplerosis may have therapeutic advantages over traditional medium-chain triglyceride (MCT) treatment of long-chain fatty acid oxidation disorders (LC-FAODs) but controlled trials have not been reported. The goal of our study was to compare the effects of triheptanoin (C7), an anaplerotic seven-carbon fatty acid triglyceride, to trioctanoin (C8), an eight-carbon fatty acid triglyceride, in patients with LC-FAODs.

METHODS

A double blinded, randomized controlled trial of 32 subjects with LC-FAODs (carnitine palmitoyltransferase-2, very long-chain acylCoA dehydrogenase, trifunctional protein or long-chain 3-hydroxy acylCoA dehydrogenase deficiencies) who were randomly assigned a diet containing 20% of their total daily energy from either C7 or C8 for 4 months was conducted. Primary outcomes included changes in total energy expenditure (TEE), cardiac function by echocardiogram, exercise tolerance, and phosphocreatine recovery following acute exercise. Secondary outcomes included body composition, blood biomarkers, and adverse events, including incidence of rhabdomyolysis.

RESULTS

Patients in the C7 group increased left ventricular (LV) ejection fraction by 7.4% (p = 0.046) while experiencing a 20% (p = 0.041) decrease in LV wall mass on their resting echocardiogram. They also required a lower heart rate for the same amount of work during a moderate-intensity exercise stress test when compared to patients taking C8. There was no difference in TEE, phosphocreatine recovery, body composition, incidence of rhabdomyolysis, or any secondary outcome measures between the groups.

CONCLUSIONS

C7 improved LV ejection fraction and reduced LV mass at rest, as well as lowering heart rate during exercise among patients with LC-FAODs.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov NCT01379625.

Predictors of Left Ventricular Functional Recovery and Their Impact on Clinical Outcomes in Patients With Newly Diagnosed Dilated Cardiomyopathy and Heart Failure

BACKGROUND

To identify the predictors of left ventricular functional recovery (LVFR) and its impacts on clinical outcomes in acute heart failure (AHF) patients with newly diagnosed dilated cardiomyopathy (DCM).

METHODS

A total of 175 consecutive patients with newly diagnosed DCM and AHF were divided into two groups according to LVFR on FU echocardiography; the recovered group (n=54, 54.3±18.5years, 31 males) vs. the non-recovered group (n=121, 60.5±15.1years, 79 males). Clinical, laboratory, and echocardiographic findings were compared, and major adverse cardiac and cerebrovascular events (MACCE) including death, rehospitalisation, and stroke were analysed.

RESULTS

Left ventricular function (LV) was normalised in 54 patients (30.8%) on follow-up echocardiography. The change in the level of N-terminal pro-B-type natriuretic peptide (ΔNT-proBNP) between initial presentation and discharge >1633.5pg/mL was an independent predictor of LVFR, whereas diabetes and LV end-systolic diameter >50mm were negative predictors of LVFR on multivariate analysis. During five years of clinical follow-up, MACCE developed in 91 patients: 58 deaths, 29 rehospitalisations, and 4 strokes. On multivariate analysis, baseline LVEF <30% and no LVFR were independent predictors of MACCE.

CONCLUSION

Left ventricular functional recovery was not uncommon in newly diagnosed DCM with AHF. The changes in NT-proBNP level during hospitalisation, diabetes, and larger initial LV size were independent predictors of LVFR, and LVFR was an independent predictor of future MACCE. Serial monitoring of NT-proBNP and LV function would be useful in the risk stratification of newly diagnosed DCM with AHF.