Plasma alpha-human atrial natriuretic peptide and volume status in chronic haemodialysis patients

The relationship between inferior vena cava diameter (VCD), collapse-index (CI) determined by echography, and alpha-human atrial natriuretic peptide (alpha-h-ANP) concentrations were studied in 19 chronic haemodialysis patients. A significant correlation was found between VCD and alpha-h-ANP before dialysis (r = 0.78; P less than 0.0001). No such correlation was found between CI, left atrial diameter and left ventricular end-diastolic diameter, and alpha-h-ANP values. In nine patients who according to vena cava indices were hypervolaemic before dialysis (group I), alpha-h-ANP concentrations were significantly greater than in ten normo- or hypovolaemic patients (group II): 392.8 +/- 134.1 pg/ml and 168.0 +/- 62.5 pg/ml respectively. Although the same amount of fluid was ultrafiltrated in both groups, alpha-h-ANP decreased significantly in group I only, whereas in group II the decrease was not significant: 392.8 +/- 134.1 to 185.2 +/- 81.7 (P less than 0.001); 168.0 +/- 62.5 to 130.0 +/- 59 respectively. After achieving normovolaemia alpha-h-ANP concentrations in patients with a mitral valve insufficiency grade I was doubled compared to normovolaemic patients without mitral valve insufficiency, suggesting that alpha-h-ANP release will also occur from the left atrium. In the latter group alpha-h-ANP values were approximately doubled compared to healthy controls. The highly significant correlation between VCD before dialysis and changes in alpha-h-ANP during dialysis with fluid removal underlines the value of vena cava diameter in estimating volume status.     

The effect of sublingual captopril versus intravenous enalaprilat on angiotensin II plasma levels

A 44-year-old woman, with a history of familial adenomatous polyposis, complicated by carcinoma of the colon, for which a proctocolectomy had been performed, now presented with metastasis located in the pancreas. Treatment consisted of chemotherapy followed by a partial pancreaticoduodenectomy. Due to ischemia, resection of the small intestines was performed the same day. After admission, a transesophageal echocardiography showed an ejection fraction of 40%. Because enteral administration of drugs was impossible, intravenous enalaprilat 2 mg once a day for 1 day followed by sublingual captopril 25 mg twice a day were started. Blood samples were taken before and after administration. After 1 day of sublingual captopril treatment the angiotensin II level decreased with more than 50%, comparable to the decrease seen after intravenous administration of enalaprilat. Sublingual captopril has been used in the treatment of hypertensive crisis and heart failure. Although frequently reported, no study has investigated the effect on angiotensin II levels after sublingual administration in heart failure patients. This case-report demonstrated that sublingual administration of 25 mg captopril twice a day yielded a considerable decrease in angiotensin II plasma levels which was comparable to the effect seen after an intravenous administration of 2 mg enalaprilat.