Diabetes mellitus (DM) increases the risk of heart failure (HF) independent of coronary heart disease and hypertension and may cause a cardiomyopathy.
DEFINITION
Diabetic cardiomyopathy has been defined as ventricular dysfunction that occurs in diabetic patients independent of a recognized cause (eg, coronary heart disease, hypertension)
EPIDEMIOLOGY
There is a well established association between diabetes and HF that is partly but not entirely linked to coronary heart disease and hypertension. Associations have also been reported between absolute blood glucose levels, glycemic control, and HF.
Factors associated with HF in adult diabetic patients are:
- Age
- Duration of diabetes
- Insulin use
- Ischemic heart disease
- Peripheral artery disease
- Elevated serum creatinine
- Poor glycemic control
- Microalbuminuria
CHARACTERISTICS
- Functional abnormalities — Left ventricular dysfunction due to diabetic cardiomyopathy is manifested by systolic and/or diastolic dysfunction.
- Pathology — These include :
- fibrosis,
- infiltration of the interstitium with periodic acid-Schiff (PAS)-positive material,
- and alterations in the myocardial capillary basement membrane, including the formation of microaneurysms.
ETIOLOGY
A variety of derangements may contribute to ventricular dysfunction, these include:
- Autonomic neuropathy may play a role in the development of left ventricular dysfunction.
- The capacity of the vascular bed to meet metabolic demands may be impaired by abnormal epicardial vessel tone and microvascular dysfunction.
- Advanced glycation end product deposition may increase LV diastolic stiffness directly by cross-linking collagen, or indirectly by enhancing collagen formation or reducing nitric oxide bioavailability.
- Decreased insulin availability or responsiveness can impair energy-independent transport of glucose across the cell membrane.
Other factors that may contribute include:
- myocardial accumulation of lipid and other toxic products of fatty acid metabolism,
- impaired calcium handling,
- upregulation of the renin-angiotensin system,
- increased reactive oxygen species,
- and mitochondrial defects.
PROGNOSIS
- Among patients with HF, those with diabetes have higher mortality rates.
- Among patients with diabetes, those who develop HF have markedly poorer survival than in those who do not.
DIABETES DRUGS TO USE WITH CAUTION IN HF
The thiazolidinediones and metformin, two classes of oral hypoglycemic drugs, have toxicities that have made them relatively or absolutely contraindicated in patients with HF.
- Thiazolidinediones can cause fluid retention which can precipitate HF. As a result, they are not recommended in patients with symptomatic heart failure and are contraindicated in NYHA class III or IV HF. TZDs may be considered as part of diabetes management in selected patients with class I-II HF with careful monitoring for fluid retention.
- Metformin is contraindicated in HF requiring pharmacologic therapy because of the risk of lethal lactic acidosis, especially in the presence hemodynamic instability or of other concurrent medical conditions such as renal insufficiency, liver disease, or severe infection with decreased tissue perfusion. The risk of lactic acidosis is probably small in patients with stable, well-compensated heart failure who have a serum creatinine concentration below 1.5 mg/dL (133 µmol/L).
THERAPY
- General considerations — Diabetic patients with heart failure are treated in the same fashion as nondiabetics. Data supporting this approach are available for both beta blockers and ACE inhibitors.
- Role of glycemic control — Tighter glycemic control is associated with lower risk of HF.
- Heart transplantation — Diabetes mellitus, even without evidence of significant end-organ damage (neuropathy, retinopathy, or nephropathy), is a relative contraindication to heart transplantation.
- Possible prevention with angiotensin inhibition — Angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) reduce disease progression and mortality in patients with overt HF.
Reviewed from UptoDate.