Postsurgical course of patients with congenitally corrected transposition of the great arteries

Because congenitally corrected transposition is a rare congenital anomaly, little is known about the prognosis of patients with this syndrome. The present study evaluated the functional status and clinical course of 73 patients (42 male and 31 female) aged 10 days to 73 years. Follow-up was 1 week to 37 years (mean 12.7 years). Particular attention was paid to the systemic right ventricle, considering the current controversies about long-term right ventricular function. Survival of patients with this condition in general was significantly below normal. The total mortality rate was 11% (8 patients) after a mean follow-up of 12.7 years (range 10 days to 37 years). Mean age at death was 18.5 years (range 6 days to 63 years). The mean age of the survivors at latest follow-up was 21.4 years (range 4 months to 73 years). In most patients, right ventricular function deteriorated and tricuspid valve regurgitation increased, which began at a very young age. Patients without associated lesions developed complications at a higher age compared with the total group. Right ventricular and tricuspid valvular function deteriorated more frequently in patients following intracardiac operation (28% and 52%, respectively) compared with patients undergoing palliative intervention (16%) or no surgery at all (28%). We conclude that survival of patients with this condition is substantially reduced compared with the natural history of an age- and gender-matched general population. This could be explained by the associated cardiac defects, but also by the anatomic condition itself.

Renal amylin binding in normotensive and hypertensive rats: effects of angiotensin converting enzyme inhibition with perindopril

OBJECTIVES

To investigate the effect of angiotensin converting enzyme inhibition with perindopril on the binding density of [125I]-rat amylin in the renal cortex in normotensive Sprague-Dawley rats, renally ablated hypertensive rats and spontaneously hypertensive rats.

DESIGN

Sprague-Dawley rats, renally ablated hypertensive rats and spontaneously hypertensive rats were administered either the angiotensin converting enzyme inhibitor perindopril or no treatment.

METHODS

The density of [125I]-rat amylin binding was measured in the renal cortex using autoradiography in vitro. The systolic blood pressure was measured by indirect tail-cuff plethysmography. The plasma renin activity was measured by radioimmunoassay.

RESULTS

The density of [125I]-amylin binding was reduced by approximately 50% in Sprague-Dawley and subtotally nephrectomized Sprague-Dawley rats after treatment with perindopril. These changes were associated with a reduction in systolic blood pressure and an increase in plasma renin activity. In contrast, amylin binding in the perindopril-treated spontaneously hypertensive rats was not reduced, despite the prevention of a rise in systolic blood pressure and an increase in plasma renin activity.

CONCLUSIONS

These findings provide further evidence for the hypothesis that there is an association among renal amylin binding, the renin-angiotensin system and blood pressure for rats of the Sprague-Dawley strain. In contrast, the lack of an effect of angiotensin converting enzyme inhibition on renal amylin binding for rats of the spontaneously hypertensive rat strain is consistent with previous findings that the changes in amylin binding in rats of this strain are not linked directly to the prevailing systemic blood pressure but may be associated with a developmental abnormality in the kidney of these rats.

Increased density of renal amylin binding sites in experimental hypertension

High-affinity binding sites for the pancreatic beta-cell hormone amylin have been reported in the kidney, and it has been postulated that these sites may be involved in the genesis of hypertension. In the present study, we have used in vivo injection of 125I-amylin and in vitro autoradiographic techniques to assess renal amylin binding in both a genetic and a surgically induced model of hypertension. In the spontaneously hypertensive rat (SHR) at 6 weeks of age, before the rise in systolic blood pressure, there was a 36% increase in density of amylin binding compared with their normotensive counterpart, the Wistar-Kyoto rat (WKY). In SHR, there was a further increase in the density of amylin binding (to 53% greater) as the systolic blood pressure rose between 6 and 12 weeks of age. Histological examination of kidneys from SHR at 12 weeks of age revealed staining for a brush border glycoprotein, normally restricted to the proximal tubules, extending from the urinary pole into half of the epithelial lining of the glomerular capsule. In contrast to WKY, these cells also bound 125I-amylin with high density in SHR. In a rat model of renal ablation and hypertension, systolic blood pressure correlated with the density of 125I-amylin binding in the renal cortex (r=.54, P=.003, n=28). The changes in amylin binding reported here suggest a possible role for this peptide and/or activation of its receptor in the genesis as well as the maintenance of hypertension.