Delayed vaccination does not improve antibody responses in splenectomized rats experiencing hypovolemic shock.

Delayed vaccination after splenectomy has been shown to increase the antibody response in normotensive rats. The purpose of this experiment was to study the effect of timing of vaccination on antibody responses in rats undergoing splenectomy and experiencing hypovolemic shock. Sixty male Sprague-Dawley rats weighing 250 to 400 g underwent either a sham abdominal surgery or splenectomy after a 30-minute period of controlled hypovolemic shock. All rats then received pneumococcal vaccinations one day, 7 days, or 28 days postoperatively. Antibody levels were determined by enzyme-linked immunosorbent assay 3 weeks after vaccination. Results were compared by analysis of variance. Animals vaccinated one day postoperatively had similar or higher antibody responses than did rats receiving delayed vaccinations after 7 or 28 days. These results were similar for immunoglobulins G and M and more importantly were consistent for animals undergoing splenectomy and sham operations. Delayed vaccinations failed to improve antibody responses when hypovolemic shock preceded splenectomy. We propose that this is the result of complex cytokine responses to hypovolemic shock. These responses have been studied extensively in the setting of septic shock but not in the setting of hypovolemic or hemorrhagic shock.

Improved antibody responses to delayed pneumococcal vaccination in splenectomized rats.

Pneumococcal vaccination following splenectomy is widely used as prophylaxis against overwhelming postsplenectomy infection. There remains controversy however, over the timing of vaccination. We hypothesized that delaying vaccination would increase the antibody response. Pneumococcal vaccinations were given at designated intervals to rats that had undergone either a sham abdominal surgery or splenectomy. Sixty male Sprague-Dawley rats, 250 to 400 g, were divided into three groups for vaccination: I, 1 day postoperatively; II, 7 days postoperatively; and III, 28 days postsplenectomy/sham. Serum antibody levels were then determined by enzyme-linked immunosorbent assay at 5 and 21 days after vaccination. Immunoglobulin (Ig) levels after delayed vaccination at 1 week postoperatively and 1 month postoperatively were significantly higher than levels from rats vaccinated 1 day postoperatively. IgM levels after vaccinations 1 week and 1 month postoperatively were also significantly higher than levels of rats vaccinated 1 day postoperatively (P < 0.05 for both IgG and IgM). On the basis of these results, we conclude that delaying vaccination after splenectomy enhances antibody responses.

Right ventricular outflow obstruction with intact ventricular septum in adults.

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.

Recurrent ischemic heart disease: the effect of advancing age.

Four thousand four hundred and thirty open heart operations were performed at Mercy Hospital of Pittsburgh from January 1, 1988, to June 30, 1992. During that period, 168 patients were evaluated for recurrent ischemic heart disease after prior coronary artery revascularization. Forty-four were treated non operatively, the mode of therapy being transluminal angioplasty or medical management. The remaining 124 patients underwent repeat coronary revascularization. An attempt was made to define the impact of advancing age on the magnitude of risk factors, morbidity, and mortality. Advancing age is not a contraindication to repeat coronary artery revascularization. The average interval between the initial operation and the need for repeat revascularization is eight years. Younger patients have progression of their coronary artery disease, but progression of the arteriosclerotic process is in their extracranial cerebral arteries, renal arteries, and aortic segments as well as the coronary arteries. The utilization of tobacco, recent myocardial infarction, diabetes mellitus, and elevation of cholesterol are strong indicators for recurrent disease and add to the risk of repeat surgical intervention.