Hybrid Approach in Acute and Chronic Aortic Disease

The management of patients with aortic disease that involves the ascending aorta, the aortic arch, and the descending aorta represent a surgical challenge. Open surgical repair remains the gold standard for aortic arch pathologies. However, this operation requires a cardiopulmonary bypass and a period of profound hypothermia and circulatory arrest, which carries a substantial rate of mortality and morbidity. For these reasons, hybrid arch repair that involves a combination of open surgery with endovascular aortic stent graft placement has been introduced as a therapeutic alternative for those patients deemed unfit for open surgical procedures. Hybrid repair requires varying degrees of invasiveness and can be performed as a single-stage procedure or as a two-stage procedure. The choice of the technique is multifactorial, depending on the characteristics of the diseased arch with regard to position of the stent graft proximal landing zone, patient fitness and comorbid status, as well as surgical expertise and hospital facilities. Among the evolving hybrid procedures is the so-called “frozen” or stented elephant trunk technique. Adapted from the classical elephant trunk technique, this approach facilitates the repair of a concomitant aortic arch and proximal descending aortic aneurysms in a single stage under circulatory arrest. This technique is increasingly being used to treat extensive thoracic aortic disease and has shown promising results.

Stem cell behavior at hypothermia: A review article

Temperature is a fundamental factor that affects many functions and structural aspects of physiological systems. Despite its importance, little studies have performed so far for investigating the compartments and mechanisms engaged in the response of cellular systems to temperature perturbation. In this review, focusing on stem cells, we tried to perform a literature review for investigating the possible ways that temperature reduction [hypothermia] affects stem cell function and behavior. Besides, using the obtained results of this investigation, the possible mechanisms are proposed. The survey indicates that profound hypothermia enhances cell adhesion by increasing the stability of E-cadherins. Furthermore, mild hypothermia increases stem cell survival by reducing oxidative stress and prevents apoptosis via the overexpression of anti-apoptotic heat shock proteins. Mild-hypothermia also promotes cell proliferation by affecting gene expression in several ways. Even though it seems that hypothermia generally reduced stem cell differentiation, some inconsistencies are observed between obtained results from the literature. Based on the obtained results, mechanisms responsible for temperature effect of hypothermia in profound and mild ranges are given that might help researcher for real experiments.

Get out of trouble during redo surgery for false aneurysm of the ascending aorta

Postoperative thoracic aortic false aneurysm is a challenging complication of aortic surgery. We describe our surgical approach for an 8-cm thoracic aorta false aneurysm in a 59-year-old woman who had previously undergone aortic surgery. Surgery must be planned carefully because massive hemorrhage during resternotomy is a dreadful complication of postoperative false aneurysm surgery. We decided to start cardiopulmonary bypass before resternotomy and use a ventricular vent from the apex, an endo-vent from the pulmonary artery, and an endo-balloon with antegrade blood cardioplegia. We successfully performed the procedure without profound hypothermia and circulatory arrest and with a low risk of hemorrhage.

Myxedema Coma in a Hypothermic, Obtunded Patient with Post-renal Acute Kidney Injury and Bacteremia in the Intensive Care Unit

We present a case of a hypothermic, unconscious patient transferred to our Intensive Care Unit with sepsis requiring mechanical ventilation. The absence of any known past medical history as well as concurrent obstructive uropathy and bacteremia made initial diagnosis challenging. He was eventually found to be in myxedema coma in light of evolving signs and laboratory investigations. This case emphasizes the need to consider myxedema coma in the differential diagnosis of profound hypothermia, especially when other clinical signs and symptoms may obscure its initial diagnosis, and lead clinicians to focus on the triggering event in isolation rather than concurrently managing hypothyroidism. This case highlights a challenging presentation of an uncommon, but life-threatening condition. We discuss the signs and symptoms present in the hypothyroid patient with myxedema coma; emphasize the pathophysiology of myxedema coma as well as the evidence-based acute management of this condition.

Comparative characteristics of the hemostasis system state during hypothermic and early reactive periods of general freeze injury in rats

Aim. To study the hemostasis system state in rats during hypothermic and post-hypothermic periods. Methods. Male Wistar rats (53 individuals) were used in the study. The animals from the experimental group underwent single immersion cooling in water at a temperature of 5 °C until profound hypothermia was reached, the control group of the animals was placed in water at a temperature of 30 °C. From the animals of the first group, blood was taken immediately after reaching profound hypothermia and from the second group - 24 hours after cooling was stopped. Results. Comparative analysis of the results showed that immediately after the end of a single cold exposure, significant increase in platelet aggregation activity occured, as well as appearance of thrombinemia markers in the bloodstream and inhibition of fibrinolytic system activity. 24 hours after the experimental exposure, these parameters returned to the initial values. When assessing the activity of external and internal ways of coagulation immediately after the termination of cooling, development of hypocoagulation was established, both with routine tests and from thromboelastography. After 24-hour period, hypocoagulation, recorded immediately after reaching the sought rectal temperature, persisted. Thus, after the end of a 24-hour period after cold exposure termination, most of the parameters of hemostatic system that had deviated immediately after the end of the experiment, returned to the normal level. The delayed effect of hypothermia in such cold exposure regimen manifested only by hypocoagulative shift at the initial stages of coagulation. Conclusion. Signs of abnormal hemostasiological blood properties, recorded immediately after the cooling termination, disappear within 24 hours, and only hypocoagulation persists in the blood.