Congenital Heart Defects: Early Surgical Correction and Heart Failure? Brief History

Abstract

The first successful cardiac surgical procedure was performed by Robert Gross in 1938 in Boston. A 7 year-old patient underwent ligation of the ductus arteriosus [1]. In 1945, Crawford carried out the first correction for coarctation of the aorta in Sweden [2,3].Technological development that allowed for the introduction of extracorporeal circulation devices led to the beginning of open heart surgery. The first heart surgery using an extracorporeal circulation device was performed by Kirklin. Extracorporeal circulation devices had multiple negative effects on the physiology of the infant and the newborn, so that at the beginning of pediatric heart surgery, the delay of surgical correction was preferred. Initially, these devices required an extremely high priming volume that exposed the child to exanguinotransfusion. Inflammation mediators [4] caused excessive vascular permeability and tissue edema, all the more so as the age of the child was younger at the time of surgery.At first, anesthesia and intensive care for children were practically non-existent, and diagnosis was made using invasive techniques (cardiac catheterization), which most frequently generated complications. Surgical kits did not contain microsurgical instruments required for working on the fragile heart tissue of the newborn and infant. Thus, a number of palliative procedures were developed, in order to help the patient survive until the performance of surgical correction.The pathophysiology of congenital heart defects includes 3 main categories. There may be a volume load in which one or both ventricles must pump more blood than normal. This usually happens because of an increased pulmonary blood flow, as a result of a septal defect. There may be a pressure load of one or both ventricles. This can be the result of an obstruction at the outlet of the ventricle. The third possibility is cyanosis that can be secondary to a reduction in pulmonary blood flow or inadequate mixing between the two parallel circulations.Systemic pulmonary shunt reduces cyanosis by increasing pulmonary blood flow. Although from a conceptual point of view it is an easy procedure, systemic pulmonary shunt can be a challenge for the surgeon. Assessing the size of the shunt depending on the weight of the child is most important. The size of the shunt must take into consideration the subsequent development of the child, but it must not be too large in order to avoid postoperative ventricular volume overload. The Blalock-Taussig shunt was introduced by the surgeon Alfred Blalock and the cardiologist Helen Taussig [5]. The original BT shunt directly connected the sectioned subclavian artery to the right pulmonary artery and was of an adequate size to substitute for the pulmonary blood flow deficiency. In addition, this shunt had growth potential and thus, it could pathophysiologically support the patient for many years. The Waterston shunt is an anastomosis between the ascending aorta and the right pulmonary artery [6]. This shunt has the disadvantage to produce excessive pulmonary blood flow and a distortion of pulmonary arteries.The Potts shunt consists of the anastomosis of the descending aorta and the left pulmonary artery. This shunt has all the disadvantages of the Waterston shunt and in addition, it is extremely difficult to remove at the time of surgical correction.The modified BT shunt, which consists of the anastomosis of the arterial brachiocephalic trunk with the right pulmonary artery, by means of a vascular prosthesis, was introduced by deLeval [7]. This shunt was initially performed in the left subclavian artery and the left pulmonary artery through thoracotomy. It has the following advantages: it does not cause pulmonary artery distortion and pulmonary overload.High blood pressure and flow in pulmonary circulation, most frequently due to a septal defect, may lead in time to pulmonary hypertension and pulmonary vascular disease. In 1950, Muller and Dammann introduced pulmonary artery banding in order to reduce high blood pressure and flow in pulmonary circulation [8]. Like in the case of shunts, banding does not allow for an increase in diameter, so that in time, with the child’s growth, this becomes increasingly tight. It can also result in pulmonary artery distortion, so that correction and the removal of banding should be initiated as soon as possible after the regression of pulmonary hypertension.In 1950, Blalock and Hanlon introduced surgical atrial septectomy for children with transposition of the great vessels with insufficient mixing [9]. Nowadays, this septectomy is an interventional procedure performed through the rupture of the septum with a balloon catheter, according to the procedure described by Rashkind [10,11].