Treatment with n-acetylcysteine in patients with heart failure and chronic renal failure leads to improvements in vascular function and in renal function.

Ten patients will be invited to participate in the trial. After obtaining informed consent, the ten patients will be randomly assigned to one month of treatment with oral n-acetylcysteine 500mg or placebo twice daily for thirty days in addition to their regular therapy. At enrolment the patients will be educated and counselled about the trial and the intervention medication. Patients will also have a blood test (serum creatinine) that will allow the calculation of their renal function by use of the Cockroft Gault equation. Blood samples will also be frozen and stored. Patients will also undergo an ultrasound test of the function of their arm blood vessels. Both the blood test and the ultrasound test will be repeated at the completion of the thirty day trial period. Again the blood test sample will be frozen and stored. Subjects will then cross over to the other treatment arm for a further one month period, with the same testing at the end.

Inclusion Criteria:

• Age 18 to 75 years inclusive;
• Patients with chronic heart failure NYHA II, III and IV and LVEF<40%. Stable medications for 1 month. Not admitted to hospital in the past month.
• Chronic renal failure with GFR (as estimated by the Cockroft Gault equation) of >30 ml/min and <50 ml/min not on any form of dialysis.

Exclusion Criteria:

• Age <18 and >75 years;
• Myocardial infarction in the preceding six months;
• Acute decompensation of renal function or heart failure in the last 30 days;
• Allergy to n-acetylcysteine or glyceryl trinitrate;
• Contraindications to the use of glyceryl trinitrate as per the product information lodged with the PBS (Australia);
• On treatment with allopurinol, vitamin C or vitamin E or other antioxidant therapy at time of randomisation (statins are acceptable);
• Acute decompensation of another organ system in the last 30 days;
• Current pregnancy.