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Increased left ventricular mass in normotensive type 1 diabetic patients with diabetic nephropathy
A Sato1, L Tarnow, H H Parving
1Steno Diabetes Center, Gentofte, Denmark.
Insights
Diabetic nephropathy in type 1 diabetes is linked to increased left ventricular mass, a risk factor for heart disease. This occurs independently of blood pressure, suggesting glycemic control and the renin-angiotensin system play key roles.
Area of Science:
- Cardiology
- Nephrology
- Endocrinology
Background:
- Diabetic nephropathy significantly elevates the risk of cardiovascular disease and mortality in type 1 diabetes patients.
- Left ventricular hypertrophy (LVH) is a potential mechanism linking diabetic nephropathy to adverse cardiovascular outcomes.
- Evaluating cardiac structure and function in normotensive type 1 diabetic patients with and without nephropathy is crucial.
Purpose of the Study:
- To assess left ventricular structure and function in normotensive type 1 diabetic patients with and without diabetic nephropathy.
- To investigate potential mechanisms, such as glycemic control and renin-angiotensin system activation, contributing to cardiac changes.
Main Methods:
- M-mode and Doppler echocardiography were used to compare 17 type 1 diabetic patients with nephropathy and 34 matched controls without nephropathy.
- Patients were matched for arterial blood pressure, age, diabetes duration, and BMI.
- Albuminuria levels were measured to define nephropathy status.
Main Results:
- Left ventricular mass (LVM) index was significantly higher in patients with nephropathy (100.8 g/m2) compared to controls (88.2 g/m2).
- Ventricular septum width was greater in the nephropathic group (9.4 mm vs. 8.2 mm).
- The nephropathic group showed a trend towards reduced diastolic function (E/A ratio 1.2 vs. 1.4) and had elevated HbA1c, plasma renin, and prorenin levels.
Conclusions:
- Increased LVM in normotensive type 1 diabetic patients with diabetic nephropathy may contribute to higher cardiac morbidity and mortality.
- Glycemic abnormalities and renin-angiotensin system activation are potential drivers of this ventricular enlargement.
- These findings highlight the importance of managing metabolic control and the renin-angiotensin system in type 1 diabetic patients with nephropathy.
Objective:
Diabetic nephropathy increases the risk of premature cardiovascular disease and sudden death, particularly in type 1 diabetic patients. One possible mechanism for this risk may be left ventricular hypertrophy. In our study, we aimed to evaluate left ventricular structure and function in normotensive type 1 diabetic patients with and without nephropathy.
Research Design And Methods:
M-mode and Doppler echocardiography was performed in 17 type 1 diabetic patients with nephropathy (albuminuria [median (range)], 345 (135-2,846) mg/24 h) and compared with 34 normotensive, normoalbuminuric (10 [3-30] mg/24 h) type 1 diabetic patients matched for arterial blood pressure (mean +/- SD) ([134/77] +/- [13/7] vs. [129/78] +/- [12/7] mmHg), age (40 +/- 11 vs. 42 +/- 10 years), duration of diabetes (28 +/- 7 vs. 28 +/- 6 years), and BMI (24.2 +/- 4.2 vs. 24.6 +/- 2.4 kg/m2).
Results:
Left ventricular mass (LVM) index was significantly higher in patients with nephropathy compared with patients with normoalbuminuria (100.8 +/- 10.3 vs. 88.2 +/- 21.0 g/m2, respectively; P = 0.02). Greater ventricular septum width was demonstrated in the nephropathic group compared with the control group (9.4 +/- 1.0 vs. 8.2 +/- 1.3 mm, respectively; P = 0.002). No significant difference in posterior wall thickness was apparent. The nephropathic group tended to have reduced diastolic function (E/A ratio, 1.2 +/- 0.3 vs. 1.4 +/- 0.4; P = 0.09). Fractional shortening was normal and about the same in the two groups. The groups did not differ with respect to serum creatinine or hemoglobin, while metabolic control (assessed by HbA1c) and plasma renin and prorenin levels were elevated in the nephropathic group compared with the normoalbuminuric group.
Conclusions:
A blood pressure-independent increase in LVM may contribute to the increased cardiac morbidity and mortality in normotensive type 1 diabetic patients with diabetic nephropathy. Glycemic abnormalities and activation of the renin-angiotensin system may lead to the ventricular enlargement.