Disorders of calcium and phosphate metabolism in patients with significant mitral regurgitation

INTRODUCTION    Although there are several known risk factors of cardiovascular diseases (CVDs), the search for new factors continues. In recent years, clinical trials have reported vitamin D and other calcium (Ca) and phosphate (P) metabolism disorders as potential new cardiovascular risk factors, but literature data on this association are limited.
OBJECTIVES    We aimed to assess the extent of Ca and P metabolism disorders in patients with mitral regurgitation (MR) and potential role of these disorders as risk factors of CVD.
PATIENTS AND METHODS    We enrolled adult patients with significant MR (vena contracta >3 mm, effective orifice area >0.2 cm2, and MR volume >30 ml/s) hospitalized in our department between July and September 2013. Anthropometric data were collected. Moreover, all patients underwent blood and urine analysis, transthoracic echocardiography, and 6‑minute walking test.
RESULTS    A total of 99 patients were enrolled (median age, 75 years; [Q1–Q3, 66.0–81.5]; women, 35.4%). The median serum Ca level corrected by albumin was 3.22 mmol/l [Q1–Q3, 3.14–3.27]. The mean (SD) serum ionized Ca level corrected by pH was 1.05 (0.08) mmol/l. The median levels of parathyroid hormone (PTH) and 25(OH)D3 were 63.10 pg/ml [Q1–Q3, 40.95–88.55] and 14.80 ng/ml [Q1–Q3, 9.93–20.12], respectively. Patients with a history of heart failure (HF) with reduced ejection fraction (New York Heart Association class IV), shorter distance in the 6‑minute walking test, lower left ventricular ejection fraction, and larger left ventricular end‑diastolic diameter had significantly higher probability of elevated PTH levels.
CONCLUSIONS    Disorders of Ca and P metabolism in patients with significant MR are a noteworthy clinical problem. Our study is the first to systematically describe these disorders in patients with CVD. However, larger studies are needed to confirm the significance of our results.