The Effect of Incorporating Vessel Compliance in a Computational Model of Blood Flow in a Total Cavopulmonary Connection (TCPC) with Caval Centerline Offset

Background—The total cavopulmonary connection (TCPC), a palliative correction for congenital defects of the right heart, is based on the corrective technique developed by Fontan and Baudet. Research into the TCPC has primarily focused on reducing power loss through the connection as a means to improve patient longevity and quality of life. The goal of our study is to investigate the efficacy of including a caval offset on the hemodynamics and, ultimately, power loss of a connection. As well, we will quantify the effect of vessel wall compliance on these factors and, in addition, the distribution of hepatic blood to the lungs. Methods—We employed a computational fluid dynamic model of blood flow in the TCPC that includes both the non-Newtonian shear thinning characteristics of blood and the nonlinear compliance of vessel tissue. Results—Power loss in the rigid-walled simulations decayed exponentially as caval offset increased. The compliant-walled results, however, showed that after an initial substantial decrease in power loss for offsets up to half the caval diameter, power loss increased slightly again. We also found only minimal mixing in both simulations of all offset models. Conclusions—The increase in power loss beyond an offset of half the caval diameter was due to an increase in the kinetic contribution. Reduced caval flow mixing, on the other hand, was due to the formation of a pressure head in the offset region which acts as a barrier to flow.

Bronchocentric mycosis occurring in transplant recipients

Although a variety of long-term, probably immunologically induced pulmonary changes have been described in recipients of both combined heart-lung and bone marrow transplantation, pulmonary infections continue to remain causes of significant morbidity and mortality as well. Herein we describe three patients (two heart-lung and one bone marrow transplant recipient) who had bronchocentric granulomatous mycosis, a tissue manifestation of fungal infection not previously described in the setting of a transplant host. Although one patient was being treated successfully with antifungal agents for his mucormycosis, two other patients eventually died of invasive aspergillosis. This emphasizes that although this process is histologically somewhat similar to bronchocentric granulomatosis, a high index of suspicion for infection needs to be maintained when this pathologic process is identified in a transplant host.

Relationship in very elderly veterans of nutritional status, self-perceived chewing ability, dental status, and social isolation

The relationship of nutritional status, self-perceived chewing ability, dental status, and social isolation was examined. Seventy-three ambulatory, elderly (means = 86 years) veterans were studied. Parameters of nutritional status included intakes of protein, carbohydrate, fat, and total calories, and hemoglobin, serum albumin, total lymphocyte count, and height/weight ratio were determined. Dental status was measured, and self-perceived chewing problems and social isolation were assessed by interview. Results showed a significant correlation between perceived chewing problems and diminished protein and total caloric intake and increased carbohydrate intake. No association was found between measured dental status and nutritional status. Social isolation was weakly correlated with greater protein and calorie intake. These results support the contention that the presence of self-perceived chewing problems are more reliable than the quality of the dentition itself as an indicator of altered nutritional status.