Heart Surgery in New Zealand: The Dramatic Evolution of a Lifesaving Specialty (Part 3)
The first heart transplant unit in New Zealand was set up at Green Lane Hospital. The programme was led by surgeon Ken Graham, together with cardiologists Trevor Agnew and Arthur Coverdale and the first heart transplant took place in 1988. A lot of work went into getting to this point.
Emergency Treatment of Heart Attacks | Although surgery and later angioplasty were dramatically effective in relieving angina, they were much less effective in reducing mortality. Pathology showed that heart attacks were not usually due to stable narrowings in the coronary arteries, but rupture of so-called unstable atheromatous plaques.
These plaques result from accumulations of cholesterol in the vessel wall, which subsequently become oxidised and provoke an inflammatory reaction. This may lead to rupture of the plaque into the vessel with formation of a blood clot on the ragged surface and blockage of the vessel, with death of the area of heart muscle which it had supplied. This process is known as myocardial infarction.
The culprit plaque may not be big enough to narrow the vessel and produce angina, and some patients who have heart attacks have had no previous warning pain. It is now known that if the blocked artery can be reopened within two hours, damage to the heart muscle can be prevented, and emergency angioplasty has been dramatically effective. If the patient lives in an area where rapid access to a base hospital is impossible drugs which dissolve clot can be used, but are less effective.
The Last Resort – Heart Transplantation | On 3 December 1967 in Cape Town, South Africa Christiaan Barnard achieved near reputational immortality by performing the world’s first heart transplant. This soon turned to notoriety, at least in cardiac circles, when it became apparent that he had usurped techniques which had been developed by others, who had not proceeded because they knew that the drugs to prevent rejection were not adequately developed. One hundred patients worldwide were transplanted in that era. None survived for a worthwhile period.
Norman Shumway, in Palo Alto, California, who Barnard had visited shortly before his operation, continued his research. The turning point came with the discovery of the highly effective immunosuppressive drug, Cyclosporine in Basil, Switzerland by the pharmaceutical company Sandoz, and it was approved for clinical use in 1983.
In New Zealand the propriety of setting up a heart transplant unit was questioned, appropriately, in view of financial constraints and long waiting lists for other heart surgery, but it was decided to proceed at Green Lane. Strict criteria and protocols were set up, together with a committee which included nurses, a psychiatrist, and a lay representative. The programme was led by surgeon Ken Graham, together with cardiologists Trevor Agnew and Arthur Coverdale. The first operation was in 1988, and the programme continues to be outstandingly successful.
More Recent Developments | Over the past 30 years the pace of change has been, inevitably, slower, as existing techniques have been refined and become more generally available. “Hybrid” operating rooms with full surgical facilities, and x-ray equipment for transcatheter interventions now allow combined procedures to be performed with one anaesthetic.
The long-term dream of a permanent artificial heart remains elusive except for a few highly selected patients. However, support with an artificial heartfor weeks, or even months, until a suitable donor for heart transplantation becomes available, the so-called “bridge to transplantation” is now practicable.
Temporary support for patients with reversible heart or lung problems, such as inflammation of the heart muscle (myocarditis)or viral pneumonia is now widely provided using extracorporeal membrane oxygenation (ECMO). ECMO is a partial form of heart-lung bypass using catheters inserted through the skin and utilising specially modified centrifugal pumps and oxygenators capable of supporting circulation and oxygenation until recovery occurs.
Transcatheter aortic valve implantation (TAVI) was developed by Alain Cribier in France in the 1990s and is now widely used to replace narrowed aortic valves, avoiding the need for open surgery. In this technique a tissue valve, usually calf pericardium (the fibrous membrane which surrounds the heart), together with an expandable metal frame is mounted on a balloon. Using x-ray control the catheter is advanced from the femoral artery in the groin and the balloon positioned across the aortic valve. The balloon is then inflated, and the valve fixed in position. Similar techniques are now being developed to replace mitral valves.
Transcatheter techniques are also now widely used for a variety of common and simple congenital defects enabling avoidance of major surgery.
Where to now? | Huge advances have been made, and will no doubt continue. But perhaps the most major challenges we now face lie in promoting these services in developing countries with large populations where advanced heart care is currently unavailable.