This guideline is dedicated to the memory of SIGN's founding chairman, Professor Jim Petrie, CBE.

It was Jim's insight which recognised the importance of a professionally led national clinical guideline programme for Scotland; his energy, commitment and the irresistible force of his personality which nurtured SIGN to fruition; and his rigorous, challenging intellect which steered its development into the nationally and internationally respected organisation it is today. Amongst his innumerable achievements, both personal and professional, we hope that SIGN will stand as a lasting tribute to Jim's memory.

Jim was an inspirational leader, a wise teacher, and trusted friend to everyone in SIGN. He is greatly missed. But we are thankful that we had the great good fortune to know Jim; and we will continue his work to improve the quality of health care for patients in Scotland and worldwide.