Renal function and urate metabolism in late survivors with cyanotic congenital heart disease.

Abstract

Diminished glomerular filtration rate, proteinuria, and large hypercellular congested glomeruli with segmental sclerosis are found in late survivors with cyanotic congenital heart disease (CCHD). Hyperuricemia is common, acute gouty arthritis is less common than uric acid levels would predict, and overt tophaceous deposits of uric acid are exceptional. The role of the kidney in causing the basic biochemical disturbances, and the relative importance of impaired urate excretion vs urate overproduction have not been established. Accordingly, we reviewed the courses of two index patients and prospectively studied eight additional CCHD patients from 28 years to 46 years old with mean hematocrits of (62 +/- 10%). Plasma creatinine concentration was normal (0.9 +/- 0.1 mg/dl) yet glomerular filtration rate was mildly reduced to 93 +/- 14 ml/min as measured by creatinine clearance and to 81 +/- 6 ml/min as measured by 111In DTPA. Three patients had significant proteinuria and one was nephrotic. Plasma uric acid concentration was high in all but one (8.2 +/- 2.1 mg/dl), mean 24 hr uric acid excretion was normal (564 +/- 221 mg), and fractional uric acid excretion was relatively low (6.3 +/- 2.6%). The two patients with highest plasma uric acid levels (12.0 and 10.2 mg/dl) had the lowest fractional excretions (2.8% and 4.0%). Both of these patients had diminished capacity to excrete a water load (38% and 27%/4 hr) and to maximally concentrate urine (520 and 635 mOsm/kg after water deprivation and vasopressin). In conclusion, high plasma uric acid levels in late survivors with CCHD are secondary to inappropriately low fractional uric acid excretion, not to urate overproduction.(ABSTRACT TRUNCATED AT 250 WORDS)

The Effects of Sevoflurane Anesthesia and Cardiopulmonary Bypass on Renal Function in Cyanotic and Acyanotic Children Undergoing Cardiac Surgery

“…12,16 In our study, urinary uric acid excretions were also lower in the cyanotic patients than in the acyanotic patients, although these differences did not reach statistical significance. Enhanced urate reabsorption appears to result from renal hypoperfusion reinforced by high filtration fraction.…”

“…17 Hyperuricemia serves as a marker of abnormal intrarenal hemodynamics. 12 In our patient cohort, serum uric acid levels at all times were higher in the cyanotic patients compared with the acyanotic patients. Classifications such as acute kidney injury network (AKIN) and risk, injury, failure, loss, end-stage (RIFLE) are used for evaluating the severity of postoperative renal dysfunction in adults.…”

“…The deranged intrarenal hemodynamics in patients with cyanotic heart disease are associated with proteinuria, increased renal blood flow, increased renal vascular resistance, decreased renal plasma flow, normal or reduced glomerular filtration rates, and histologic changes on biopsy or at autopsy. 5,12 Cyanotic glomerulopathy has been shown to be associated with elevated hematocrit. Perfusion of the tubular apparatus, which is most vulnerable to ischemic damage, is provided by the capillaries of the peritubular plexus.…”

“…Enhanced urate reabsorption appears to result from renal hypoperfusion reinforced by high filtration fraction. 12 The serum uric acid levels have been found previously to be higher in the cyanotic children compared with the acyanotic children undergoing cardiac operations. 17 Hyperuricemia serves as a marker of abnormal intrarenal hemodynamics.…”

A Case of Abdominal Pain, Hypoxia and Clubbing

“…Cyanotic congenital heart disease is rarely diagnosed in adults, but carries a five-year mortality of 12.6% [4]. Complications from untreated cyanotic congenital heart disease include erythrocytosis, problems with hemostasis, hyperuricemia, renal dysfunction, cerebrovascular accidents, endocarditis, brain abscesses, supraventricular and ventricular arrhythmias, and the development of Eisenmenger's Syndrome [3,[5][6][7][8]. Female patients may experience a delay in menarche or menorrhagia and if they chose to become pregnant, pregnancies may result in a high incidence of miscarriage, premature births or low birth weight babies [9,10].…”