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Cardiovascular abnormalities in patients with X-linked hypophosphatemia
1Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Insights
Cardiovascular abnormalities, including hypertension and left ventricular hypertrophy, may occur in X-linked hypophosphatemia (XLH) patients. Close monitoring for these conditions is recommended.
Area of Science:
- Pediatric Nephrology
- Cardiovascular Medicine
- Medical Genetics
Background:
- X-linked hypophosphatemia (XLH) treatment can cause hypercalcemia and nephrocalcinosis.
- Cardiovascular abnormalities are not previously reported in XLH patients.
Purpose of the Study:
- To evaluate cardiovascular status in patients with X-linked hypophosphatemia.
- To investigate potential cardiovascular complications in XLH.
Main Methods:
- Assessed cardiovascular status in 13 XLH patients.
- Utilized electrocardiogram and ultrasonography for left ventricular hypertrophy diagnosis.
- Performed exercise stress testing to evaluate blood pressure response.
Main Results:
- All patients had mild to moderate nephrocalcinosis.
- Left ventricular hypertrophy diagnosed in 7/13 children.
- XLH patients showed abnormal diastolic blood pressure increase during exercise stress testing.
Conclusions:
- Patients with XLH may develop hypertension and left ventricular hypertrophy.
- Further investigation into the mechanisms and therapeutic guidelines for XLH cardiovascular complications is needed.
- Close monitoring of XLH patients for cardiovascular abnormalities is recommended.
Abstract:
Treatment for X-linked hypophosphatemia (XLH; vitamin D metabolites and phosphate salts) may result in hypercalcemia, hypercalciuria, nephrocalcinosis, and hyperparathyroidism. Cardiovascular abnormalities occur in association with these complications, but have not been reported in XLH. We hypothesized that such abnormalities may occur in XLH and evaluated cardiovascular status in 13 patients with this disease. All patients were asymptomatic and had normal cardiovascular physical examinations and Holter studies. Serum calcium and creatinine clearance were normal in all. However, all patients had mild to moderate nephrocalcinosis. Left ventricular hypertrophy was diagnosed by electrocardiogram in three and by ultrasonography in seven children. Baseline blood pressure (BP) was normal (mean +/- SD, 116 +/- 15/74 +/- 6 mm Hg). During exercise stress testing, systolic BP increased in all patients, but the maximal systolic pressure was less than that in healthy age- and sex-matched controls (156 +/- 20 vs. 175 +/- 23; P = 0.002, by t test). An abnormal increase in diastolic BP occurred at all levels of work load in XLH patients; their peak exercise diastolic BP was 91 +/- 12 vs. 72 +/- 6 mm Hg in controls (P < 0.0001, by t test). Whether these abnormal findings are primary defects in XLH or represent complications of treatment is unclear. Patients with XLH should be monitored closely for the development of hypertension and left ventricular hypertrophy. Investigation of the mechanisms involved and establishment of therapeutic guidelines are indicated.