Cardiac Surgery

Excerpt

Cardiac surgery is the specialty of medicine concerning the surgical treatment of pathologies related to the heart and thoracic aorta. The spectrum of modern cardiac surgery can be understood by its history beginning at the end of the 19th century. Since then cardiac surgery developed through the work of numerous dedicated surgeons offering more and more treatments for diverse cardiac pathology. This development is still ongoing today.

In 1882, Billroth performed the first pericardiectomy. The first successful treatment of cardiac trauma was done by Ludwig Rehn when he operated on a cardiac stab wound in 1896 against the wide held belief that the heart is not an organ on which surgeons should operate. The development of cardiopulmonary bypass was necessary to reach the structures of interest and was pushed by the high mortality of the early cardiac operations like embolectomy (first completed by Trendelenburg).

Surgical revascularization is one option to relieve ischemic heart disease with complicated atherosclerosis. Vineberg implanted the left internal mammary artery (LIMA) into the anterior free wall forming no direct anastomoses to the coronary vessels. He has observed, in earlier experiments, that collaterals develop when ischemia is present. During the 1960s several surgeons in different locations pioneered the first coronary artery bypass grafting (CABG) operations. The era of reversing coronary artery disease started with the invention of cardiac catheterization by Forssman in 1929 and injection of contrast media to visualize coronary vessels and locate stenosis by Shirey in 1962. Bypass grafting and interventional revascularisation form the 2 main possibilities to treat ischemic heart disease besides drug treatment.

Surgical treatment of valvulopathies started closed mitral commissurotomy by passing a finger or instrument through the narrow orifice of the mitral stenosis to dilate or cut it as did Cutler in 1923 for the first time. The Hufnagel cage and ball valve was the first artificial valve introduced in 1952. It was placed in the descending thoracic aorta to prohibit blood flow reversal in aortic regurgitation. In 1967 a similarly structured valve, the Edwards cage and ball valve, had been implanted 1000 times for mitral valve disease. Surgical techniques improved from early, single valve procedures to 4-valve replacement in 1992. Special techniques were introduced, for example, the Ross procedure replacing the aortic valve with pulmonic valve autograft. To treat proximal aortic dissection or aneurysm, Bentall implanted an artificial aortic valve combined with ascending aortic vessel prosthesis.

In 1944, cardiac surgeons Blalock, Taussig, and Thomas first forayed into the field of congenital heart lesions, when they operated on the tetralogy of Fallot, one of the cyanotic heart lesions.There are also acyanotic heart lesions such as pulmonary stenosis.

Regarding cardiac arrhythmias, the Cox-Maze procedure offers surgical treatment of atrial fibrillation. The evolution of cardiac pacemakers started by applying external electrodes to stimulate the heart. Lillehei placed electrodes directly to the heart during open heart surgery. The first implanted pacemaker lasted only 8 hours. Modern aggregates offer long-lasting solutions to diverse rhythm abnormalities.

In 1967, several surgical teams around the world performed the first heart transplantations: Barnard in South Africa, Shumway in Stanford (offering increased post-transplant survival by adding immunosuppressive treatment), and Kantrowitz with pediatric transplantation in New York.

Some devices can supply mechanical circulatory support. Since 1963, the intra-aortic balloon pump (IABP) enhanced left ventricular function through the mechanism of counterpulsation. Open heart surgery requires a cardiopulmonary bypass (CPB) to temporarily replace the human heart and lung by an external circuit consisting of pumps and an oxygenation membrane. Artificial hearts were first applied extracorporal in 1982. Later devices allowed for implantation.

Cardiac surgery represents high operative and perioperative risk requiring professional staff and advanced equipment. Besides the diseases that require cardiac surgery, the perioperative period shows a variety of characteristic pathologies: systemic inflammatory response following CBP, myocardial stunning and low cardiac output syndrome, arrhythmias, massive transfusion requirements and multiorgan involvement with kidney injury, stroke, and respiratory distress.

With the surge of interventional and minimally invasive methods to treat cardiac pathologies, the medical fields of cardiology and cardiac surgery recently need to adapt to these changes. As Lytle and Mack described in their 2005 editorial, "The times they are changing" the field of cardiac surgery is undergoing a fundamental transformation. In his presidential address, Guyton said: "if we do not embrace innovation we will become its victims." Recent developments include the upcoming of cardiac arrest centers, broader and simpler application of extracorporeal membrane oxygenation (ECMO), organizational changes such as fast-track hospital stay, and interprofessional decision making by heart teams, and challenges posed by an aging patient population.