SAT-066 EFFECTS OF PARATHYROIDECTOMY ON NOCTURNAL NON-DIPPING HEART RATE IN STAGE 5 CKD PATIENTS

Abstract

In healthy population 24-hour heart rate (HR) displays a circadian pattern, peaking shortly after waking and falling during the night, a phenomenon known as “dipping”. Non-dipping HR is defined as nighttime HR decreased less than 10% as compared to daytime readings, which is an independent risk factor for increased cardiovascular diseases (CVD) and all-cause mortality. It is well known that patients with chronic kidney disease-mineral and bone disorder (CKD-MBD) have high risk of CVD and mortality, however, the associations between CKD-MBD and non-dipping HR remain uncertain. Here we evaluated the features of 24-hour HR in stage 5 chronic kidney disease (CKD) and the effects of parathyroidectomy (PTX) on HR circadian rhythm in severe secondary hyperparathyroidism (SHPT) patients. The cross-sectional study included 213 stage 5 CKD patients and 96 controls. A prospective follow-up study was conducted in 47 PTX patients. Blood examinations and 24-hour Holter monitoring were measured. HR in each hour, daytime (8:00 AM-19:59 PM) and nighttime (20:00 PM-7:59 AM) mean HR values were recorded. Night/day HR ratio was calculated as nighttime/daytime ratio of heart rate, when greater than 0.90 could be considered as non-dipping HR. Stage 5 CKD patients and healthy controls were matched for age and sex. Compared with controls, CKD patients had higher blood pressure, lower body mass index (BMI), hemoglobin, hematocrit, serum albumin and total cholesterol values. In addition, stage 5 CKD group had higher circulating adjusted calcium (Ca), phosphorus (P), alkaline phosphatase (ALP) and intact parathyroid hormone (iPTH) levels. Stage 5 CKD patients display higher 24-hour, daytime and nighttime mean HR than controls. Night/day HR ratio in controls and CKD patients were 0.81±0.080, 0.91±0.075 respectively (P＜0.0001) (Table 1). Night/day HR ratio had closely positive correlations with baseline serum Ca, iPTH and ALP, while negatively related with serum urea and albumin levels. In CKD patients, the dipping patterns of 24-hour HR were shallower in both non-PTX and PTX group, especially in severe SHPT patients(Figure 1). After PTX (median follow-up interval: 11.84±11.33 months), the non-dipping HR pattern was reversed in severe SHPT patients, and Night/day HR ratio decreased from 0.92±0.077 to 0.88±0.075 (P=0.01) (Figure 2). Twenty four hour heart rate in stage 5 CKD patients displayed non-dipping pattern, mainly due to increased nighttime HR. Severe SHPT patients have more serious non-dipping HR, which could be reversed by parathyroidectomy. Rhythm abnormalities of heart rate are suggested to be taken seriously and treated effectively in order to decrease CVD and all-cause mortality in CKD-MBD patients.