Open heart surgery (OHS) is defined as any operation where the chest is opened to allow the surgeon direct access to the heart muscle, valves, or arteries. For centuries, the heart was viewed as an organ too delicate and complex to be touched. The development of techniques to safely open the heart chambers and fix congenital or acquired damage fundamentally changed modern medicine, allowing physicians to repair previously untreatable internal heart defects.
Early Attempts at Heart Repair
Before surgeons could venture inside the heart, they focused on “closed heart” operations performed on the beating heart without opening its internal chambers. The successful repair of congenital defects, such as patent ductus arteriosus and coarctation of the aorta, marked the beginning of cardiac surgery. Surgeons were limited by the necessity of continuous blood flow to the brain and other organs, meaning the heart could not be stopped for more than a few moments without causing irreversible damage. This fundamental challenge meant that complex internal problems, like holes between the chambers, remained untouchable.
Strategies for Limited Open Access
A transitional phase in the early 1950s allowed surgeons a brief window of time to work inside the heart. The primary strategy involved systemic hypothermia, the controlled cooling of the patient’s entire body. Lowering the body temperature slows metabolism, reducing oxygen demands and extending the time a patient could survive without blood circulation. Surgeon F. John Lewis performed the first successful internal cardiac repair using this technique on September 2, 1952, closing an atrial septal defect. This method, often combined with controlled inflow occlusion (clamping major blood vessels), provided a critical window measured in single-digit minutes, meaning only simple defects could be corrected.
The Breakthrough of Artificial Circulation
The definitive solution to the time constraint of cardiac surgery was the invention of a machine that could temporarily take over the functions of the heart and lungs. This technology, known as Cardiopulmonary Bypass (CPB) or the heart-lung machine, was the culmination of decades of work by surgeon John Gibbon. The CPB machine works by diverting deoxygenated blood away from the heart and lungs, oxygenating it outside the body, and then returning the oxygen-rich blood to the patient’s arterial system. This process allows the surgeon to stop the heart, creating a bloodless, motionless surgical field for an extended period. On May 6, 1953, Dr. Gibbon used the heart-lung machine to successfully close an atrial septal defect in 18-year-old Cecelia Bavolek. This procedure marked the first time a human heart defect was repaired with circulation supported artificially, ushering in the modern era of cardiac surgery.
Expanding the Range of Cardiac Procedures
The clinical impact of reliable Cardiopulmonary Bypass was significant, allowing surgeons to move beyond the simple defects limited by hypothermia. The ability to safely stop the heart for prolonged periods made repairs for complex congenital heart defects, such as Tetralogy of Fallot, possible. Following Gibbon’s success, the scope of cardiac surgery expanded rapidly in the ensuing decade. Surgeons began performing life-saving interventions such as heart valve replacement surgery, where damaged valves could be replaced with artificial ones. This also enabled the development of coronary artery bypass grafting (CABG), a procedure that reroutes blood flow around blocked arteries.