Strain estimation in aortic roots from 4D echocardiographic images using medial modeling and deformable registration.

Even though the central role of mechanics in the cardiovascular system is widely recognized, estimating mechanical deformation and strains in-vivo remains an ongoing practical challenge. Herein, we present a semi-automated framework to estimate strains from four-dimensional (4D) echocardiographic images and apply it to the aortic roots of patients with normal trileaflet aortic valves (TAV) and congenital bicuspid aortic valves (BAV). The method is based on fully nonlinear shell-based kinematics, which divides the strains into in-plane (shear and dilatational) and out-of-plane components. The results indicate that, even for size-matched non-aneurysmal aortic roots, BAV patients experience larger regional shear strains in their aortic roots. This elevated strains might be a contributing factor to the higher risk of aneurysm development in BAV patients. The proposed framework is openly available and applicable to any tubular structures.

The Program Evaluation Committee in the Adult Cardiothoracic Anesthesiology Fellowship - Harnessing Opportunities for Program Improvement.

The Program Evaluation Committee has an essential role in the quality improvement process of the adult cardiothoracic anesthesiology fellowship. The annual program evaluation presents all stakeholders with an opportunity to evolve with the changing needs and opportunities of the fellowship milieu. The active engagement of the program in this process is a high-quality approach to successful planning, preparation and conduct of the self-study and site visit that are important extensions of the annual program evaluation and the program evaluation committee.

Clinical update in liver transplantation.

There has been considerable recent progress liver transplantation (LTX). The postreperfusion syndrome has clearly defined and typically responds to vasopressin and/or methylene blue when refractory to catecholamine therapy. Diastolic dysfunction and cirrhotic cardiomyopathy are prevalent and important in LTX recipients. The high cardiovascular risk and the increasing medical complexity of the current liver transplant recipient have stimulated the publication of guidelines for cardiovascular assessment before LTX. Cardiac surgery is increasingly more successful in patients with cirrhosis, including simultaneous heart-liver transplantation. Cardiopulmonary bypass in LTX is indicated for hemodynamic rescue and, at some centers, serves as the hemodynamic platform for liver implantation. Although acute renal injury is common after LTX, early diagnosis is now possible with novel biomarkers. Earlier detection of postoperative renal dysfunction may prompt intervention for renal rescue. The metabolic milieu in LTX remains critical. Regular insulin therapy may be more effective than infrequent large bolus therapy for potassium homeostasis. Careful titration of insulin therapy may improve freedom from severe hyperglycemia to decrease morbidity. Since the organization of dedicated anesthesia care teams for LTX improves perioperative outcome, this aspect of perioperative care is receiving systematic attention to optimize safety and quality. The specialty of LTX is likely to continue to flourish even more, given these pervasive advances.

Preoperative cardiac risk assessment for noncardiac surgery: defining costs and risks.

Cardiac risk stratification before noncardiac surgery remains important. Two major areas have been emphaized, namely, cost-effective risk stratification and enhanced identification of high risk populations. Recent studies have highlighted the lack of quality and affordable medical consultation. The indications for resting preoperative echocardiography merit streamlining, given recent data that failed to demonstrate tangible benefit. Further more, noninvasive cardiac stress testing is expensive and unnecessary in low risk patients. Perioperative troponin determination significantly improves the detection of myocardial infarction, facilitating its early management. The revised cardiac risk index is a standard tool for risk stratification, despite multiple limitations. The first approach has been tore calibrate the traditional risk index to specific high-risk surgical subgroups. The second approach has been to develop new cardiac risk models with more power. Both approaches have yielded risk calculators that out perform the traditional risk model. Furthermore, this latest generation of risk models is available as online calculators that can be accessed at the bedside. Further clinical trials are indicated to test the validity, clinical utility, and cost-effectiveness of these novel risk calculators. It is likely that these powerful instruments will refine the indications for specialized cardiac testing, offering multiple opportunities to reduce perioperative risk and cost simultaneously.

Leukotoxin confers beta-hemolytic activity to Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans is the etiologic agent of localized aggressive periodontitis, a rapidly progressing oral disease that occurs in adolescents. A. actinomycetemcomitans can also cause systemic disease, including infective endocarditis. In early work on A. actinomycetemcomitans workers concluded that this bacterium is not beta-hemolytic. More recent reports have suggested that A. actinomycetemcomitans does have the potential to be beta-hemolytic. While growing A. actinomycetemcomitans on several types of growth media, we noticed a beta-hemolytic reaction on media from one manufacturer. Beta-hemolysis occurred on Columbia agar from Accumedia with either sheep or horse blood, but not on similar media from other manufacturers. A surprising result was that mutants of A. actinomycetemcomitans defective for production of leukotoxin, a toxin that is reportedly highly specific for only human and primate white blood cells, are not beta-hemolytic. Purified leukotoxin was able to lyse sheep and human erythrocytes in vitro. This work showed that in contrast to the accepted view, A. actinomycetemcomitans leukotoxin can indeed destroy erythrocytes and that the production of this toxin results in beta-hemolytic colonies on solid medium. In light of these results, the diagnostic criteria for clinical identification of A. actinomycetemcomitans and potentially related bacteria should be reevaluated. Furthermore, in studies on A. actinomycetemcomitans leukotoxin workers should now consider this toxin's ability to destroy red blood cells.