RESUMEN
Cardiothoracic surgeons whose practice is limited to adults rarely see patients with right ventricular outflow obstruction and an intact ventricular septum. Of more than 10,000 open-heart procedures performed at our institution from 1983 to 1993 (in patients 18 to 75 years old), only 5 procedures were for correction of this problem. Both the pulmonary valve and the subvalvular area were abnormal in these 5 patients, and 4 of the 5 had subvalvular stenosis. The gradient across the right ventricular outflow tract was measured by cardiac catheterization before repair in all patients and averaged 118 mmHg. Various surgical approaches were used for repair. In the 2 patients whose pressures were measured postoperatively, the gradients were 25 mmHg and 45 mmHg, respectively. There were no operative deaths. At follow-up (range, 2 months to 5 years after surgery), all patients were in New York Heart Association functional class I and all had murmurs. Those who underwent echocardiography were found to have minimal gradients across the right ventricular outflow tract.
Asunto(s)
Cardiomiopatía Hipertrófica/complicaciones , Válvula Pulmonar/anomalías , Obstrucción del Flujo Ventricular Externo/cirugía , Adulto , Anciano , Cateterismo Cardíaco , Ecocardiografía Transesofágica , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Obstrucción del Flujo Ventricular Externo/complicaciones , Obstrucción del Flujo Ventricular Externo/diagnósticoRESUMEN
Normothermic retrograde continuous cardioplegia is a revolutionary development for myocardial preservation in cardiac surgery. Despite excellent reports regarding this technique, the surgical community has expressed concern over technical problems encountered. The method of normothermic retrograde continuous cardioplegia in current use requires both large total crystalloid volumes and large potassium loads to deliver adequate cardioplegia. We have developed a technique that eliminates these problems. The heart is stopped by an initial infusion of normothermic cardioplegic solution through a coronary sinus catheter. The infusate is then converted to normothermic pump blood. Small boluses of potassium chloride are added intermittently to maintain cardiac arrest. We applied this technique to 35 patients undergoing cardiac valve surgery. The average volume of crystalloid cardioplegia required was 125 mL (range, 40 to 155 mL), and the average total potassium load was 52 mEq (range, 2 to 100 mEq). Clinically significant sequelae were noted in 4 patients (11%), and 1 (3%) died of pneumonia on the 28th postoperative day. The method we describe is a safe and effective alternative to the current technique of normothermic retrograde continuous cardioplegia and offers both physiologic and technical advantages to patients undergoing cardiac valve procedures.