Professor Denis Melrose

Heart-lung machine designer

Denis Graham Melrose, clinical physiologist: born Cape Town, South Africa 20 June 1921; Lecturer, then Reader, Royal Postgraduate Medical School 1948-68, Professor of Surgical Science 1968-83 (Emeritus); married 1948 Ann Warter (two sons); died Santa Eulalia, Ibiza 2 July 2007.

Denis Melrose was a doctor who specialised in clinical physiology and became a professor in the new discipline of clinical rheology – the science of flow in the body. He made two important contributions to the development of open-heart surgery in the 1950s, a time when this type of surgery was only just becoming a practical possibility: he designed a heart-lung machine, and he invented a method of producing cardiac arrest during surgery.

Heart operations before then had been limited to procedures on the intact beating heart, such as dilating the mitral valve with a finger placed though the wall of the heart or on operations on the vessels around the heart.

Melrose came from a medical family, his father being a doctor in Cape Town, where Denis was born in 1921. The family came to Britain before the Second World War and after pre-clinical studies at University College, Oxford, Melrose went to London, to University College Hospital Medical School for his clinical work. One of his teachers there was the cardiologist Sir Thomas Lewis.

After qualifying in 1945 Melrose served in the Royal Navy for two years and then had the good fortune to obtain a lecturer's post in the Department of Surgery at the Royal Postgraduate Medical School at Hammersmith Hospital, whose head was Professor Ian Aird.

Aird had the vision of creating artificial heart and kidney machines and he enthusiastically supported Melrose in his ambition to design a heart-lung machine that would enable the surgeon to operate on a bloodless heart with cardio-pulmonary bypass, and repair defects such as holes in the heart under direct vision. At about that time a Hungarian refugee, Francis Kellerman, had established a medical instrument firm called New Electronic Products (NEP) and, in spite of severe financial constraints, he collaborated with Melrose to design and manufacture the Melrose-NEP heart-lung machine.

This was first used at Hammersmith Hospital on 17 April 1957 on a 30-year-old woman with an atrial septal defect – she was in good health 25 years later. The apparatus was soon in use in other centres across the UK, and also in New Zealand and Australia. Melrose gave great personal support to the units starting to do open-heart surgery.

A group of Russian surgeons in Moscow were also keen to carry out open-heart surgery and decided to buy the Melrose machine. In May 1959, a team from Hammersmith Hospital led by Melrose – with the surgeons Bill Cleland and Hugh Bentall, the anaesthetist John Beard, theatre sister Phyllis Bowtle, technician John Robson and the cardiologist Arthur Hollman – went to the Institute of Cardiovascular Surgery on Leninsky Prospect, Moscow, with half a ton of equipment.

Four children with severe congenital heart lesions were successfully operated on. Indeed, two of them had lesions on which the surgeons had not previously operated. This was possibly the first time that a group of foreign doctors had actually worked in the Soviet Union as distinct from being shown the alleged wonders of Soviet medicine.

The team were congratulated by the Soviet deputy prime minister Anastas Mikoyan, who embraced Phyllis Bowtle and said, "Medicine is clean, politics are dirty." The group flew home on the inaugural flight of the Tupolev 104, the Soviet copy of the Comet aircraft.

Although cardio-pulmonary bypass allowed the surgeon to open the heart and correct defects inside with no time constraints, the heart itself was still beating, which was tiresome for the surgeon and made precise surgery difficult. Several other centres in Europe and the United States were also designing heart-lung machines, but Melrose's unique contribution was the development of elective cardiac arrest. He and others devised a method of stopping the heart from beating during open-heart surgery using a chemical method.

Laboratory work on animals by Melrose, Bentall, B. Dryer and J.B.E. Baker in 1955 led to the clinical application whereby a solution of potassium citrate was perfused into the heart at the time of open-heart surgery and cardiac arrest produced under control of the surgeon. By 1984 this method had been used with complete success in over 100 patients at Hammersmith. Potassium arrest is today a standard procedure in cardiac surgical units throughout the world, but now using the St Thomas' Hospital cardioplegic solution.

Melrose continued to work at the Royal Postgraduate Medical School until his retirement in 1983, when he was made Emeritus Professor.

Denis Melrose had the ideal temperament to lead innovative methods in medicine. He had an exceptionally friendly, outgoing personality, was full of fun, and yet had an obviously firm understanding of apparatus and clinical procedures. Outside medicine his great love was sailing and after his retirement he and his wife Ann went to live in Ibiza, where his hobby could be pursued to the full.

Arthur Hollman