Impact of hybrid thoracoabdominal aortic repair on visceral and spinal cord perfusion: The new and improved SPIDER-graft

Effects of fluids vs. vasopressors on spinal cord microperfusion in hemorrhagic shock induced ischemia/reperfusion

OBJECTIVE

Spinal cord injury induced by ischemia/reperfusion is a devastating complication of aortic repair. Despite developments for prevention and treatment of spinal cord injury, incidence is still considerably high majorly impacting patient outcome. Microcirculation is paramount for tissue perfusion and oxygen supply and often dissociated from macrohemodynamic parameters used to guide resuscitation. Effects of fluids vs. vasopressors in the setting of hemodynamic resuscitation on spinal cord microperfusion are unknown. Aim of this study was to compare the effects of vasopressor and fluid resuscitation on spinal cord microperfusion in a translational acute pig model of hemorrhagic shock induced ischemia/reperfusion injury.

METHODS

We designed this study as prospective randomized explorative large animal study. We induced hemorrhagic shock in 20 pigs as a model of global ischemia/reperfusion injury. We randomized animals to receive either fluid or vasopressor resuscitation. We measured spinal cord microperfusion using fluorescent microspheres as well as laser-Doppler probes. We monitored and analyzed macrohemodynamic parameters and cerebrospinal fluid pressure.

RESULTS

Spinal cord microperfusion decreased following hemorrhagic shock induced ischemia/reperfusion injury. Both fluids and vasopressors sufficiently restored spinal cord microperfusion. There were no important changes between groups (percentage changes compared to baseline: fluids 14.0 (0.31-27.6) vs. vasopressors 24.3 (8.12-40.4), p = .340). However, cerebrospinal fluid pressure was higher in animals receiving fluid resuscitation (percentage changes compared to baseline: fluids 27.7 (12.6-42.8) vs. vasopressors -5.56 ((-19.8)-8.72), p = .003). Microcirculatory resuscitation was in line with improvements of macrohemodynamic parameters.

CONCLUSIONS

Both, fluids and vasopressors, equally restored spinal cord microperfusion in a porcine acute model of hemorrhagic shock induced ischemia/reperfusion injury. However, significant differences in cerebrospinal fluid pressure following resuscitation were present. Future studies should evaluate these effects in perfusion disruption induced ischemia/reperfusion conditions of microcirculatory deterioration.

Endovascular Treatment of Aortic Pathologies in Patients With Marfan Syndrome: Single-Center Experience

OBJECTIVES

To study the outcome of endovascular treatment of aortic pathologies in patients with Marfan syndrome (MFS) at a single institution.

METHODS

Consecutive MFS patients who underwent endovascular repair or hybrid procedures for aortic pathologies from January 2010 to May 2020 were identified. Several endovascular and hybrid strategies have been used. Technical success, short- and mid-term survival, complications, and re-interventions were retrospectively analyzed.

RESULTS

During the study period, 24 patients with MFS (median age, 48 [13-78] years; 58% males) were treated. Indications for intervention were chronic aortic dissection with aneurysm degeneration in 16 patients (67%), acute type B aortic dissection in 4 patients (17%), aortic aneurysm without any dissection in 3 patients (13%), and aortic intramural hematoma in 1 patient (4%). Most patients were asymptomatic (83%), three (13%) were symptomatic and one (4%) had a contained rupture. The median aneurysm diameter was 56 (35-86) mm. Hybrid procedures were performed in 7 (29%) patients. Thoracic endovascular repair was performed in 12 (50%) patients, a fenestrated or branched endovascular aortic repair in 4 (17%) patients, and placement of an iliac artery stent-graft in 1 (4%) patient. Procedures were staged in 12 (50%) patients. Technical success was achieved in all patients. The median intensive care unit stay was 6 (range, 1-30) days, and the median hospital stay was 23 (range, 3-112) days. Early mortality was reported in 1 (4%) patient. Wound infection was seen in 7 (29%) patients and gastrointestinal complications in 3 (13%) patients. The median follow-up was 42 (range, 1-127) months. The cumulative survival rate was 87% at 24 months. The cumulative freedom from re-intervention was 77% at 12 months.

CONCLUSIONS

Endovascular treatment of aortic pathologies in patients with MFS appears feasible with acceptable early and mid-term outcomes in terms of mortality and re-intervention rates. Endovascular therapy plays an increasing role in MFS patients with aortic pathology.

The Important Role of Endothelium and Extracellular Vesicles in the Cellular Mechanism of Aortic Aneurysm Formation

Homeostasis is a fundamental property of biological systems consisting of the ability to maintain a dynamic balance of the environment of biochemical processes. The action of endogenous and exogenous factors can lead to internal balance disorder, which results in the activation of the immune system and the development of inflammatory response. Inflammation determines the disturbances in the structure of the vessel wall, connected with the change in their diameter. These disorders consist of accumulation in the space between the endothelium and the muscle cells of low-density lipoproteins (LDL), resulting in the formation of fatty streaks narrowing the lumen and restricting the blood flow in the area behind the structure. The effect of inflammation may also be pathological dilatation of the vessel wall associated with the development of aneurysms. Described disease entities strongly correlate with the increased migration of immune cells. Recent scientific research indicates the secretion of specific vesicular structures during migration activated by the inflammation. The review focuses on the link between endothelial dysfunction and the inflammatory response and the impact of these processes on the development of disease entities potentially related to the secretion of extracellular vesicles (EVs).

The use of pulse pressure variation for predicting impairment of microcirculatory blood flow

Dynamic parameters of preload have been widely recommended to guide fluid therapy based on the principle of fluid responsiveness and with regard to cardiac output. An equally important aspect is however to also avoid volume-overload. This accounts particularly when capillary leakage is present and volume-overload will promote impairment of microcirculatory blood flow. The aim of this study was to evaluate, whether an impairment of intestinal microcirculation caused by volume-load potentially can be predicted using pulse pressure variation in an experimental model of ischemia/reperfusion injury. The study was designed as a prospective explorative large animal pilot study. The study was performed in 8 anesthetized domestic pigs (German landrace). Ischemia/reperfusion was induced during aortic surgery. 6 h after ischemia/reperfusion-injury measurements were performed during 4 consecutive volume-loading-steps, each consisting of 6 ml kg⁻¹ bodyweight⁻¹. Mean microcirculatory blood flow (mean Flux) of the ileum was measured using direct laser-speckle-contrast-imaging. Receiver operating characteristic analysis was performed to determine the ability of pulse pressure variation to predict a decrease in microcirculation. A reduction of ≥ 10% mean Flux was considered a relevant decrease. After ischemia–reperfusion, volume-loading-steps led to a significant increase of cardiac output as well as mean arterial pressure, while pulse pressure variation and mean Flux were significantly reduced (Pairwise comparison ischemia/reperfusion-injury vs. volume loading step no. 4): cardiac output (l min⁻¹) 1.68 (1.02–2.35) versus 2.84 (2.15–3.53), p = 0.002, mean arterial pressure (mmHg) 29.89 (21.65–38.12) versus 52.34 (43.55–61.14), p < 0.001, pulse pressure variation (%) 24.84 (17.45–32.22) versus 9.59 (1.68–17.49), p = 0.004, mean Flux (p.u.) 414.95 (295.18–534.72) versus 327.21 (206.95–447.48), p = 0.006. Receiver operating characteristic analysis revealed an area under the curve of 0.88 (CI 95% 0.73–1.00; p value < 0.001) for pulse pressure variation for predicting a decrease of microcirculatory blood flow. The results of our study show that pulse pressure variation does have the potential to predict decreases of intestinal microcirculatory blood flow due to volume-load after ischemia/reperfusion-injury. This should encourage further translational research and might help to prevent microcirculatory impairment due to excessive fluid resuscitation and to guide fluid therapy in the future.

Experimental Devices Versus Hand-Sewn Anastomosis of the Aorta: A Systematic Review and Meta-Analysis

BACKGROUND

To minimize complications associated with the construction of the hand-sewn aortic anastomosis, alternative experimental methods have been pursued. This study aimed to evaluate the efficacy of experimental anastomotic devices in relation to time and point of rupture of the anastomosis in comparison to the conventional technique.

MATERIALS AND METHODS

An electronic search was performed using MEDLINE, Scopus, Science Direct, and Cochrane Library databases by two independent authors. Our exclusion criteria referred to studies reporting results solely from end-to-side anastomosis, results on vessels other than the aorta, studies that did not involve animal experiments, and non-English publications. The last search date was January 1, 2020.

RESULTS

The meta-analysis included 22 studies with 34 anastomosis samples and a total of 316 animals. The pooled mean automated anastomosis time was 10.38 min, and the mean point of rupture was 32.7 N. In the subgroup analysis of automated anastomosis time by device category, the anastomotic stenting technique reported significantly lower anastomosis time but also showed significantly lower point of rupture. Comparing the efficacy of experimental devices and the hand-sewn technique, our pooled analysis showed that automated devices significantly decrease the time needed to perform the anastomosis (weighted mean difference -7.24 min). On the other hand, the automated anastomosis is also associated with decreased tensile strength (weighted mean difference -20.68 N).

CONCLUSIONS

Although experimental devices seem to offer a faster anastomosis, they lack endurance when compared with the hand-sewn technique. Further research is needed for the development of an "ideal" anastomotic technique.

Aneurysms and dissections - What is new in the literature of 2019/2020 - a European Society of Vascular Medicine annual review

More than 6,000 publications were found in PubMed concerning aneurysms and dissections, including those Epub ahead of print in 2019, printed in 2020. Among those publications 327 were selected and considered of particular interest.