Kirklin, John W.

Open operation by means of extracorporeal circulation has been used on 47 patients with congenital aortic stenosis at the Mayo Clinic between April 1955 and July 1, 1960; 33 patients had valvular stenosis, 11 had subvalvular stenosis, and three had supravalvular stenosis. The over-all operative mortality rate was 13 per cent; 6 per cent of patients with valvular aortic stenosis died in the hospital. Severe aortic insufficiency did not develop in any patient operated on for valvular aortic stenosis although a diastolic murmur was present after operation in some. Rarely, however, was the transvalvular gradient completely eliminated by operation although 90 per cent of the surviving patients were either asymptomatic or had definite clinical improvement. Late follow-up hemodynamic studies suggest that a persistent transvalvular gradient may regress in time. Relief of obstruction caused by subvalvular variety of aortic stenosis is difficult whether stenosis is localized or diffuse. Even in this gruop, however, it has been possible to achieve good results with careful attention to certain technical details. Patients with congenital aortic stenosis should be operated on before the development of the sequelae of severe left ventricular hypertension.

From March 1955 to April 1959, 174 patients with ventricular septal defect and 124 patients with ventricular septal defect associated with pulmonic stenosis were referred from the Section of Pediatrics of the Mayo Clinic for open intracardiac repair. Forty-eight of these 298 patients had complete heart block at some time following operation. Eighteen of the patients with heart block died in the immediate postoperative period, 18 had reversion to normal sinus rhythm, and 12 were discharged from the hospital with complete heart block. Three of these 12 patients died subsequently. Two died presumably as a direct result of complete heart block and a third died following a second open cardiac operation. Of the 9 surviving patients, 3 have had serious bradycardia or periods of asystole and 6 have no symptoms from heart block. One of 3 surgical technics was employed for all the patients in this study with variation in incidence of block with the use of each technic. Other factors that might relate to the incidence of heart block are discussed. The management of the patient with complete heart block both in the immediate post-operative period and after dismissal from the hospital is described.

Calcareous disease of the aortic valve, diagnosed by fairly uniform signs and measurements, has been treated in 14 cases at the Mayo Clinic by an open surgical technic with utilization of extracorporeal circulation. One patient died during the operation and another died after leaving the hospital. Among 7 cases followed 6 to 9 months after operation, definite symptomatic improvement has been shown in 6. This disease is very dangerous, but a small improvement in the size of the valvular orifice can bring important benefits. The open operation is advantageous in avoidance of creating or aggravating insufficiency while relieving stenosis. Presently this operation is advised for patients whose disability is significant or progressing. Severe coexisting coronary artery disease is a contraindication; but associated aortic valvular insufficiency, advanced degrees of disability, and left ventricular failure are not.

Of 128 children with anatomically confirmed interatrial communications 74 had ostium secundum, 37 had ostium primum defects, 5 had common atrium, and 12 had total anomalous pulmonary venous connection. Analysis of the medical history, physical examination, roentgenogram, and electrocardiogram resulted in accurate diagnosis in most instances. In 6 of the 128 patients the proper diagnosis was not made: 3 infants with total anomalous pulmonary venous connection died within a few hours after admission to the hospital and did not have proper diagnostic evaluation; the condition of 3 other patients with ostium secundum defects was misdiagnosed as ostium primum defect before surgical treatment. In patients with ostium secundum and ostium primum defects the symptoms, signs, roentgenologic data, and findings at cardiac catheterization are similar, but differences in respect to the electrocardiograms are striking when the latter are subjected to vectorial analysis. The QRS loop is clockwise in the presence of ostium secundum defect and counterclockwise when ostium primum defect is at hand. Clinical and roentgenologic manifestations also are noted among patients with common atrium and total anomalous pulmonary venous connection, and the findings at cardiac catheterization likewise may be similar, but the electrocardiographic differences are significant. The QRS loop is counterclockwise in patients with common atrium and clockwise in patients with total anomalous pulmonary venous connection.

Estimation of pulmonary blood flow relative to systemic blood flow is a critical point in selecting patients with ventricular septal defect and severe pulmonary hypertension for operation. A detailed medical history, physical examination, thoracic roentgenograms, careful interpretation of electrocardiograms, cardiac catheterization, and biopsy of the lung provide approaches to the problem. In borderline cases, decision still may be extremely difficult. The authors usually favor operation, however, with recognition that this decision may be in error. Obviously proper evaluation for operation cannot assure uniformly good results. Method of conduct of operation, perfusion, and postoperative care determine the results.

Analysis of accumulated experience with the repair of atrial septal defect in 119 adults has revealed several factors determinable preoperatively that appear to have a strong influence on the operative risk. These factors are related to the presence of pulmonary vascular disease or heart failure and contribute importantly to the selection of patients for operation.

The relative importance of organic changes and vasoconstrictive influences in the production of increased pulmonary vascular resistance in congenital heart disease is problematic. With use of a grading system previously described, a study was made of the relation between each of the grades of hypertensive pulmonary vascular disease associated with ventricular or atrial septal defects and the change of pulmonary artery blood pressure immediately following closure of the abnormal communications. The immediate reversibility of the pulmonary hypertension varies inversely with the severity of the structural changes.