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Left ventricular diastolic impairment in type 1 diabetic patients with microalbuminuria
B Watschinger1, C Brunner, A Wagner
1Universitätsklinik für Innere Medizin III, Abteilung für Nephrologie und Dialyse, Wien, Austria.
Abstract:
The high incidence of cardiac mortality in type 1 diabetic patients is further increased when diabetic nephropathy is present. Since microalbuminuria (albumin excretion rate > 30 mg/day) represents an incipient stage of diabetic nephropathy, we decided to investigate whether incipient renal changes correlate with early diastolic cardiac dysfunction, known to preceed systolic dysfunction. To test this hypothesis, 13 normotensive type 1 diabetics with incipient nephropathy (mean age 37.8 +/- 3.5, diabetes duration 18.8 +/- 2.6 years), 13 type 1 diabetics without nephropathy (matched for age, diabetes duration and metabolic control) or other microangiopathic changes and 13 normal controls were studied. Diseases known to affect left ventricular performance were ruled out before investigation. Right and left ventricular parameters were assessed by M-mode and Doppler echocardiography. While parameters for left ventricular systolic function stayed within the normal range and did not differ between the two diabetic groups (ejection fraction 69.3 +/- 2.4 vs. 69.6 +/- 1.4%; fractional shortening 40.3 +/- 2.2 vs. 38.5 +/- 1.1%), diastolic function was significantly impaired in diabetic patients with microalbuminuria. This is expressed by an inversed early and late peak flow velocity ratio in patients with microalbuminuria (0.988 +/- 0.04 vs. 1.362 +/- 0.1; p < 0.05) and a significant percentual increase in late (atrial) filling (39.1 +/- 1.7 vs. 29.9 +/- 1.4% when compared to whole filling; p < 0.05) despite a similar rate-corrected isovolumetric relaxation period in both diabetic groups (98.4 +/- 5.8 vs. 95.5 +/- 6.2).(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Type 1 diabetes with incipient nephropathy shows early diastolic cardiac dysfunction. Microalbuminuria, an early kidney change, correlates with impaired heart function in diabetic patients.
Area of Science:
- Cardiology
- Nephrology
- Endocrinology
Background:
- Type 1 diabetes mellitus (T1DM) carries a high risk of cardiac mortality, exacerbated by diabetic nephropathy.
- Microalbuminuria signifies early-stage diabetic nephropathy and may indicate broader microvascular complications.
Purpose of the Study:
- To investigate the correlation between incipient renal changes (microalbuminuria) and early diastolic cardiac dysfunction in type 1 diabetic patients.
- To assess if early kidney damage precedes detectable systolic dysfunction in T1DM.
Main Methods:
- Studied three groups: T1DM with microalbuminuria, T1DM without nephropathy, and healthy controls.
- Utilized M-mode and Doppler echocardiography to assess right and left ventricular parameters.
- Excluded participants with conditions known to affect cardiac performance.
Main Results:
- Left ventricular systolic function remained normal and similar in both diabetic groups.
- Diastolic function was significantly impaired in T1DM patients with microalbuminuria.
- Impaired diastolic function manifested as an altered early/late peak flow velocity ratio and increased atrial filling.
Conclusions:
- Incipient nephropathy, indicated by microalbuminuria, is associated with early diastolic cardiac dysfunction in type 1 diabetes.
- Diastolic dysfunction may be an early indicator of cardiac involvement in T1DM, preceding systolic impairment.