Beneficial haemodynamic effects of insulin in chronic heart failure

Predictors of Health-Related Quality of Life Among Patients with Type II Diabetes Mellitus Who Are Insulin Users: A Multidimensional Model

BACKGROUND

Diabetes Mellitus is a progressive, chronic and multifactorial endocrine disorder characterized by elevated serum glucose levels. It has a direct effect to social and health related quality of life.

OBJECTIVE

This study aimed to determine the health-related quality of life among patients with type II diabetes mellitus (T2DM) using insulin therapy.

METHODS

Cross-sectional observational study design was used to collect data from Malaysian patients with T2DM. Subjective and objective assessments were made either by using several questionnaires or each patient's specific medication profile registered to care sites. Study participants were recruited from both public hospitals and community health clinics located in Kuala Lumpur, Malaysia.

RESULTS

A total of 430 patients with T2DM were recruited in this study with a response rate of 94.7%. The oral antidiabetic medication (OAM) group consisted of 63.0% of the study population and the rest (37.0%) were Insulin users. The body mass index and glycosylated hemoglobin patterns were significantly different between groups (P < 0.011 and P < 0.001). Insulin users showed high percentages of healthy body mass index index (44.7%) compared with OAM users (35.8%) and controlled glycemic index (glycosylated hemoglobin ≤7.5%) was significantly (P = 0.001) better among the insulin-user group compared with the OAM group. The Euro Quality of Life-5 dimension domain analysis indicated significant differences with domains of usual work (P < 0.047), pain and discomfort (P < 0.041), and anxiety and depression (P < 0.001) among insulin users versus OAM users. We also observed a significant difference between the groups regarding diet, monitoring, and disease-specific knowledge. The mean (SD) adherence score showed that insulin users were significantly (P < 0.001) more adherent (6.09 [2.98]) than OAM were nonadherent (4.19 [4.68]).

CONCLUSIONS

This study suggests the valuable effect of insulin therapy among patients with T2DM compared with OAMs on health-related quality of life, medication adherence, and health state. Insulin users reported they had better diabetes-related knowledge and treatment adherence characteristics than noninsulin users.

Dose Modification of Antidiabetic Agents in Patients with Type 2 Diabetes Mellitus and Heart Failure

Heart failure is the most common comorbidity of diabetes. The incidence of heart failure in patients with diabetes is about 9%-22%, which is four times higher Than that in patients without diabetes. Heart failure and diabetes are collectively associated with increased morbidity and mortality compared to either condition alone. Several epidemiological studies have demonstrated an increased risk of heart failure in patients with diabetes; moreover, poor glycemic control accounts for the increased risk of heart failure. At present, several oral (metformin, sulfonylureas, thiazolidinediones, dipeptidyl peptidase-4 inhibitors, etc.) as well as injectable (insulins, glucagon-like peptide 1 receptor agonists) antidiabetic agents are available. However, optimal treatment strategy to achieve adequate glycemic control in patients with type 2 diabetes mellitus (T2DM) and heart failure has not been well studied. In the view of rising prevalence of heart failure in patients with diabetes mellitus, clinicians need to understand the potential implications of antidiabetic agents in patients with heart failure. A group of experts from across India were involved in a consensus meeting in Pondicherry during the National Insulin Summit in November 2015. They evaluated agents currently available for the treatment of diabetes looking at existing scientific evidence relevant to each class of therapy. In addition, the existing guidelines and prescribing literature available with all these agents were also reviewed. Findings from the expert evaluations were then factored into the national context incorporating personal experience and common clinical practices in India. The purpose of this consensus document is to assist the clinicians while treating patients with T2DM and heart failure.

Effect of acute hyperglycemia on left ventricular contractile function in diabetic patients with and without heart failure: two randomized cross-over studies

BACKGROUND

It is unknown whether changes in circulating glucose levels due to short-term insulin discontinuation affect left ventricular contractile function in type 2 diabetic patients with (T2D-HF) and without (T2D-nonHF) heart failure.

MATERIALS AND METHODS

In two randomized cross-over-designed trials, 18 insulin-treated type 2 diabetic patients with (Ejection Fraction (EF) 36 ± 6%, n = 10) (trial 2) and without systolic heart failure (EF 60 ± 3%, n = 8) (trial 1) were subjected to hyper- and normoglycemia for 9-12 hours on two different occasions. Advanced echocardiography, bicycle exercise tests and 6-minute hall walk distance were applied.

RESULTS

Plasma glucose levels differed between study arms (6.5 ± 0.8 mM vs 14.1 ± 2.6 mM (T2D-HF), 5.8 ± 0.4 mM vs 9.9 ± 2.1 mM (T2D-nonHF), p<0.001). Hyperglycemia was associated with an increase in several parameters: maximal global systolic tissue velocity (Vmax) (p<0.001), maximal mitral annulus velocity (S'max) (p<0.001), strain rate (p = 0.02) and strain (p = 0.05). Indices of increased myocardial systolic contractile function were significant in both T2D-HF (Vmax: 14%, p = 0.02; S'max: 10%, p = 0.04), T2D-nonHF (Vmax: 12%, p<0.01; S'max: 9%, p<0.001) and in post exercise S'max (7%, p = 0.049) during hyperglycemia as opposed to normoglycemia. LVEF did not differ between normo- and hyperglycemia (p = 0.17), and neither did peak exercise capacity nor catecholamine levels. Type 2 diabetic heart failure patients' 6-minute hall walk distance improved by 7% (p = 0.02) during hyperglycemia as compared with normoglycemia.

CONCLUSIONS

Short-term hyperglycemia by insulin discontinuation is associated with an increase in myocardial systolic contractile function in type 2 diabetic patients with and without heart failure and with a slightly prolonged walking distance in type 2 diabetic heart failure patients. (Clinicaltrials.gov identifier NCT00653510).

The effect of chronic heart failure and type 2 diabetes on insulin-stimulated endothelial function is similar and additive

Aim

Chronic heart failure is associated with endothelial dysfunction and insulin resistance. The aim of this investigation was to study insulin-stimulated endothelial function and glucose uptake in skeletal muscles in patients with heart failure in comparison to patients with type 2 diabetes.

Methods

Twenty-three patients with systolic heart failure and no history of diabetes, seven patients with both systolic heart failure and type 2 diabetes, 19 patients with type 2 diabetes, and ten healthy controls were included in the study. Endothelial function was studied by venous occlusion plethysmography. Insulin-stimulated endothelial function was assessed after intra-arterial infusion of insulin followed by co-infusion with serotonin in three different dosages. Forearm glucose uptake was measured during the insulin infusion.

Results

Patients with systolic heart failure had impaired insulin-stimulated endothelial function. The percentage increase in blood flow during co-infusion with insulin and serotonin dose response study was 24.74% ± 6.16%, 23.50% ± 8.32%, and 22.29% ± 10.77% at the three doses respectively, compared to the healthy control group 45.96% ± 11.56%, 67.40% ± 18.11% and 84.57% ± 25.73% (P = 0.01). Insulin-stimulated endothelial function was similar in heart failure patients and patients with type 2 diabetes, while it was further deteriorated in patients suffering from both heart failure and diabetes with a percentage increase in blood flow of 19.15% ± 7.81%, −2.35% ± 11.76%, and 5.82% ± 17.70% at the three doses of serotonin, respectively. Forearm glucose uptake was impaired in patients with heart failure compared to healthy controls (P = 0.03) and tended to be further impaired by co-existence of diabetes (P = 0.08).

Conclusion

Systolic heart failure and type 2 diabetes result in similar vascular insulin resistance and reduced muscular insulin-stimulated glucose uptake. The effects of systolic heart failure and type 2 diabetes appear to be additive.

Effects of GIK (glucose-insulin-potassium) on stress-induced myocardial ischaemia

Despite the evidence in experimental animal models that insulin, or GIK (glucose-insulin-potassium), improves left ventricular function and perfusion during both acute and chronic ischaemia, clinical studies have generated conflicting results. We tested the hypothesis that pretreatment with GIK attenuates the vascular and functional effects of stress-induced myocardial ischaemia in humans. Twenty-two patients with evidence of inducible myocardial ischaemia were enrolled; 11 patients with normal ventricular function underwent two dipyridamole echocardiography tests, and 11 with regional contractility defects from previous myocardial infarction were submitted to two ECG exercise tests combined with 201Tl myocardial perfusion scintigraphy; the tests were preceded by 60 min of either normal saline or an isoglycaemic GIK infusion. On a stress echocardiogram, a 30% reduction in the severity of ischaemia was observed. On ECG ergometry, GIK infusion slightly increased the time to ischaemia (+0.6 min, P=0.07); however, the higher workload (+8%, P=0.07) was achieved at a similar rate-pressure plateau. On scintigraphy, an increase in ischaemic segments (+48%, P<0.001) was imaged mainly at the expense of viable (but non-ischaemic) and non-viable segments, which were reduced by 60%. GIK affected stress-induced left ventricular underperfusion only marginally (GIK: 39.7+/-2.5 compared with saline: 35.4+/-2.2 units, P<0.05), but significantly improved its acute reversibility (-42+/-4 compared with -25+/-4%, P<0.001). We conclude that GIK pretreatment attenuates the effect of ischaemia on myocardial contractility, slightly improves exercise tolerance and causes a more rapid and diffuse recovery of post-ischaemic reperfusion.

Heart failure and diabetes mellitus: epidemiology and management of an alarming association

Diabetes mellitus is a growing epidemic with a prevalence among patients with heart failure (HF) approaching 30%. Diabetes worsens the prognosis of HF, and the pathophysiology is complex and multifactorial. Early detection of subtle alterations in cardiac function by modern tools, such as Doppler echocardiography or brain natriuretic peptide dosage, is thus important in these patients. All drugs known to be effective in HF with systolic dysfunction are also effective in patients with diabetes. Angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists also seem particularly useful. Overall, however, little is known about the treatment of diabetic patients with HF, especially in case of preserved systolic function. Ongoing and future trials should help to determine the best treatment for these patients with or without associated diabetes. This review assesses the relationships between diabetes mellitus and HF and discusses the various medical strategies.

Metabolic effects of phosphodiesterase III inhibitors: another reason to promote their use?

Phosphodiesterase III inhibitors combine positive inotropic and vasodilator properties. These inhibitors are therefore frequently used to treat low cardiac output and/or severe left heart failure associated with cardiac surgery. Their effects on energy metabolism and visceral organ function are not well studied, however, particularly in comparison with their 'competitors' in daily practice (that is, catecholamines).

Influence of insulin and free fatty acids on contractile function in patients with chronically stunned and hibernating myocardium

It is unknown whether short-term modulation of substrate supply affects cardiac performance in heart failure patients with chronic ischemic myocardium. The aim of this study was to determine whether modulation of myocardial substrate metabolism with insulin and free fatty acids (FFAs) affects contractile function of chronically stunned (CST) and hibernating (HIB) myocardium at rest and after maximal exercise. We studied eight nondiabetic patients with ejection fraction (EF) 30 ± 4% (SE) and CST/HIB in 49 ± 6% of the left ventricle: 36 ± 6% CST and 13 ± 2% HIB as determined by 99mTechnetium-Sestamibi single photon emission computed tomography (SPECT) and [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET). Each patient was subjected to a 3-h infusion of 1) saline, 2) insulin-glucose (i.e., euglycemic insulin clamp; high insulin, suppressed FFA), and 3) somatostatin-heparin (suppressed insulin, high FFA). Echocardiographic endpoints were global EF and regional contractile function [maximum velocity ( Vmax) and strain rate (εmax)] as determined by tissue Doppler imaging at steady state and after maximal exercise. EF was similar at baseline and steady state and increased after exercise to 36 ± 5% ( P < 0.05). Baseline regional Vmax and εmax were highest in control, intermediate in CST and HIB, and lowest in infarct regions ( P < 0.05). Steady-state EF, Vmax, and εmax were not affected by metabolic modulation in any region. After maximal exercise, contractile function increased in control, CST, and HIB ( P < 0.05), but not in infarct, regions. Exercise-induced contractile increments were unaffected by metabolic modulation. Metabolic modulation does not influence contractile function in CST and HIB regions. Chronic ischemic myocardium has preserved ability to adapt to extreme, short-term changes in substrate supply at rest and after maximal exercise.

Effects of insulin on left ventricular function during dynamic exercise in overweight and obese subjects

AIMS

We designed this study in order to determine the effect of insulin on cardiac function in overweight and obese subjects during exercise.

METHODS AND RESULTS

The cardiac function of 62 normal glucose tolerant subjects, aged 30-40 and divided into normal weight (group 1, n=22, BMI 20-24.9 kg/m(2)), overweight (group 2, n=20, BMI 25-29.9 kg/m(2)), and obesity (group 3, n=20, BMI 30-35 kg/m(2)) was evaluated at rest and during dynamic exercise through angiocardioscintigraphy, when on hyperinsulinaemic euglycaemic clamp (test A) and when on normal saline infusion (test B). Left ventricular function at rest was statistically greater (P<0.05) in both tests in overweight and obese subjects compared with normal weight controls, with no statistical difference (P=0.057) within groups between insulin and normal saline infusion. During exercise, cardiac function improved in all the subjects in both tests. The increase was lower in overweight and obese patients, even if statistically significant only in obese vs. control subjects in both tests (P<0.05). Insulin sensitivity showed a significant correlation (P< or =0.001) with left ventricular ejection fraction (LVEF) at rest and with change in LVEF during clamp.

CONCLUSION

Our findings suggest a metabolic pathogenesis for the impaired LV function in obesity.

Determinants of insulin sensitivity in chronic heart failure

OBJECTIVE

To describe the determinants of insulin sensitivity (IS) in chronic heart failure (CHF), we created a model in which the influence of lifestyle factors and etiology of heart failure on IS were incorporated concomitantly with age, left ventricular ejection fraction (LVEF) and parameters of body composition.

DESIGN

Observational cohort study.

SETTING

Outpatient clinic for chronic heart failure.

PATIENTS

Fifty-seven male CHF patients [NYHA class II-III, age 61+/-9 years, body mass index (BMI) 26.9+/-3.3 kg/m2 (mean+/-S.D.)].

INTERVENTIONS

Euglycemic hyperinsulinemic clamp, cycle ergometry, anthropometric measurements, LVEF and a physical activity questionnaire.

MAIN OUTCOME MEASURES

A model explaining the variance of IS in CHF.

RESULTS

IS was 18.2+/-8.6 microg.kg(-1).min(-1).mU(-1).l(-1), fasting insulin level was 15.9+/-11.0 mU/l and fasting glucose level was 5.5+/-0.6 mmol/l. Peak VO2 was 19.1+/-4.9 ml.kg(-1).min(-1) and LVEF 26.2+/-7.1%. IS was inversely associated with fasting insulin concentration (r=-0.50, P<0.001) and BMI (r=-0.54, P<0.001). After controlling for BMI, IS also revealed a correlation with age (r=-0.36, P<0.01). The model explained 60% of variance in IS: BMI contributed 20%, smoking 17%, age 17% and physical activity in daily life (DPA) 16% (all P<0.05) to the variance of IS, whereas LVEF (9%) and etiology of heart failure (8%) contributed moderately.

CONCLUSIONS

In CHF patients, IS is for a major part predicted by BMI, smoking, age, daily physical activity, LVEF and etiology of heart failure.

Effets cardiovasculaires de la rosiglitazone

PROVEN EFFICACY

Since their launch on the French market in 2002, thiazolidinediones ("glitazones") prescribing conditions and therapeutic indications have progressively widened, although remaining strictly defined by the marketing licence. Clinical efficacy on glycemic control (HbA1c and glycemia), as well as beneficial metabolic effects (on lipids, insulinresistance and beta-cellular function) are now well established. Their side effects, generally minor or mild, are also well known. The problem of cardiovascular adverse events, although of a low incidence, should be known and recognized, notably fluid retention (and oedema) and risk of heart failure, more frequent in diabetic than in non diabetic patients. Clinicians must know and take into account the particular risk factors, clinical and diagnosis characteristics, possible pathophysiological mechanisms and their main preventive measures. POTENTIAL BENEFICIAL EFFECTS: On the other hand, numerous experimental and/or preliminary data in type 2 diabetic patients, including favourable effects on the various pathophysiological mechanisms involved in atherosclerosis and effects on cardiovascular risk factors or markers, justifies further large prospective long term clinical studies to assess glitazone effects on cardiovascular morbidity and mortality in type 2 diabetic patients at high cardiovascular risk. Several controlled studies are currently ongoing with rosiglitazone (ADOPT, BARI-2D, DREAM, RECORD, etc.), their results within the next coming Years will answer the questions on the anticipated benefits of rosiglitazone in terms of cardiovascular prevention and/or protection in type 2 diabetic patients.

Cœur, Diabète et Glitazones

Beneficial metabolic effects of rosiglitazone are now well established and its adverse events, generally minor or mild well known too. Following a brief review of these metabolic effects and main adverse events, we mainly describe fluid retention (and edema) and the heart failure risk, their risk factors, clinical and diagnosis characteristics, possible pathophysiological mechanisms and the main preventive measures are reviewed. Numerous experimental data and/or preliminary studies in type 2 diabetic patients, including effects on cardiovascular risk factors or markers, justify to conduct a large prospective long term clinical program to assess rosiglitazone effects on cardiovascular morbidity and mortality in type 2 diabetic patients at high cardiovascular risk, these studies are briefly described.

Insulin ameliorates exercise ventilatory efficiency and oxygen uptake in patients with heart failure–type 2 diabetes comorbidity

OBJECTIVES

This study sought to test whether insulin improves exercise ventilatory efficiency (VE/VCO2 slope) and oxygen uptake at peak exercise (peak VO2) in patients with type 2 diabetes-heart failure (HF) comorbidity.

BACKGROUND

In type 2 diabetes-HF comorbidity, depression of alveolar-capillary diffusion (DL(CO)) correlates with deterioration of exercise VE/VCO2 slope and peak VO2. Insulin potentiates DL(CO) in these patients.

METHODS

Exercise ventilatory efficiency and peak VO2 (cycle ergometry ramp protocol), as well as DL(CO) at rest and its subdivisions (membrane conductance [D(M)] and pulmonary capillary blood volume [V(C)]) were assessed in 18 patients with type 2 diabetes-HF comorbidity at baseline and after 50 ml of saline + regular insulin (10 IU), or saline, was infused on consecutive days, according to a random crossover design. Glycemia was kept at pre-insulin level for the experiment duration.

RESULTS

Baseline DL(CO), D(M), peak VO2, and VE/VCO2 slope were compromised in these patients. At measurements performed in the 60 min after infusions, compared with at baseline, saline was ineffective, whereas insulin augmented peak VO2 (+13.5%) and lowered VE/VCO(2) slope (-18%), and also increased time to anaerobic threshold (+29.4%), maximal O2 pulse (+12.3%), aerobic efficiency (+21.2%), DL(CO) (+12.5%), and D(M) (+21.6%), despite a reduction in V(C) (-16.3%); insulin did not vary cardiac index and ejection fraction at rest. Changes in peak VO2 and VE/VCO2 slope (r = 0.67, p = 0.002; r = -0.73, p < 0.001, respectively) correlated with those in DL(CO). These responses were unrelated to glycohemoglobin and baseline fasting blood sugar. They were persistent at 6 h after insulin infusion, and were undetectable at 24 h.

CONCLUSIONS

In diabetes-HF comorbidity, insulin causes a prolonged improvement in physical performance through activation of multiple factors, among which facilitation of gas conductance seems to be predominant.

Effects of glucose-insulin-potassium infusion on chronic ischaemic left ventricular dysfunction

BACKGROUND

Glucose-insulin-potassium (GIK) infusion improves cardiac function and outcome during acute ischaemia.

OBJECTIVE

To determine whether GIK infusion benefits patients with chronic ischaemic left ventricular dysfunction, and if so whether this is related to the presence and nature of viable myocardium.

METHODS

30 patients with chronic ischaemic left ventricular dysfunction had dobutamine echocardiography and were given a four hour infusion of GIK. Segmental responses were quantified by improvement in wall motion score index (WMSI) and peak systolic velocity using tissue Doppler. Global responses were assessed by left ventricular volume and ejection fraction, measured using a three dimensional reconstruction. Myocardial perfusion was determined in 15 patients using contrast echocardiography.

RESULTS

WMSI (mean (SD)) improved with dobutamine (from 1.8 (0.4) to 1.6 (0.4), p < 0.001) and with GIK (from 1.8 (0.4) to 1.7 (0.4), p < 0.001); there was a similar increment for both. Improvement in wall motion score with GIK was observed in 55% of the 62 segments classed as viable by dobutamine echocardiography, and in 5% of 162 classed as non-viable. There was an increment in peak systolic velocity after both dobutamine echocardiography (from 2.5 (1.8) to 3.2 (2.2) cm/s, p < 0.01) and GIK (from 3.0 (1.6) to 3.5 (1.7) cm/s, p < 0.001). The GIK effects were not mediated by changes in pulse, mean arterial pressure, lactate, or catecholamines, nor did they correlate with myocardial perfusion. End systolic volume improved after GIK (p = 0.03), but only in 25 patients who had viable myocardium on dobutamine echocardiography.

CONCLUSIONS

In patients with viable myocardium and chronic left ventricular dysfunction, GIK improves wall motion score, myocardial velocity, and end systolic volume, independent of effects on haemodynamics or catecholamines. The response to GIK is observed in areas of normal and abnormal perfusion assessed by contrast echocardiography.

Differentiation of the metabolic and vascular effects of insulin in insulin resistance in patients with chronic heart failure

Chronic heart failure (HF) is associated with insulin resistance. Putative mechanisms of insulin resistance are abnormal skeletal muscle blood flow and antagonism of insulin action due to sympathetic nervous system activation. We measured insulin sensitivity, the vasoactive properties of insulin, and the association between insulin resistance and markers of neurohormonal activation in 10 patients with chronic HF and in 9 healthy controls. Noninvasive hemodynamic measurements and an hyperinsulinemic, euglycemic clamp were used. Patients were insulin resistant compared with the controls (p <0.05 for area under insulin dose-response curve). Insulin infusion led to a selective increase in forearm blood flow accompanied by a decrease in mean arterial pressure and superior mesenteric blood flow. Heart rate decreased in patients but not in controls; however, when baseline measurements were controlled for, there was no difference in the overall hemodynamic response to insulin infusion between the study groups. In univariate analysis, age, serum creatinine, fasting insulin, and triglyceride levels correlated inversely with insulin sensitivity (p <0.05 for all). Cardiac output had a significant correlation with insulin sensitivity (p <0.05). On stepwise multiple linear regression analysis, only age and fasting plasma insulin emerged as significant predictors of insulin sensitivity (R(2) 0.613, p = 0.001). In particular, we found no evidence of a relation between insulin sensitivity and plasma noradrenaline. Patients with chronic HF exhibit significant metabolic insulin resistance. Insulin resistance is not secondary to failure of insulin-mediated vasodilatation or sympathetic nervous system activation and is likely due to abnormalities at the level of the skeletal myocyte.