A reappraisal of retrograde cerebral perfusion

A single-center experience in the use of hybrid techniques for thoracic aortic pathology

The hybrid method of treating thoracic aortic pathology is devoid of the disadvantages of traditional open surgery and, at the same time, has a broader range of applications than the endovascular method. From 2014 to 2019, we researched 122 patients with thoracic aortic pathology treated with the hybrid method (open surgery with thoracic endovascular aortic repair (TEVAR) at the National M. Amosov Institute of Cardiovascular Surgery National Academy of Medical Science of Ukraine. In the general group, 34 patients had a descending aortic aneurysm without dissection or rupture; 71 patients had an aortic dissection (10 - acute, 9 - subacute, 52 - chronic), penetrating aortic ulcer (PAU) - 7, thoracoabdominal aneurysm (Crawford I-II) - 4, isolated aortic arch aneurysm - 2, residual enlargement aorta after previous ascending aortic grafting causing type A acute aortic dissection (TAAD) - 3, primary aortic thrombosis - 1. Patients admitted as elective surgery candidates had switched aortic arch vessels (debranching) in the first stage and TEVAR in the second stage. For emergencies (aortic rupture with uncontrolled bleeding, malperfusion syndrome), TEVAR operation was performed first. Long-term results of treatment after three and six months are satisfactory. The hybrid technique of aortic arch treatment using modern minimally invasive technologies can eliminate the pathology in the most dangerous segment of the main artery of the body, providing a reasonable level of hospital mortality - 4.2%, and a small number of neurological complications.

The Role of Deep Hypothermia in Cardiac Surgery

Hypothermia is defined as a decrease in body core temperature to below 35 °C. In cardiac surgery, four stages of hypothermia are distinguished: mild, moderate, deep, and profound. The organ protection offered by deep hypothermia (DH) enables safe circulatory arrest as a prerequisite to carrying out cardiac surgical intervention. In adult cardiac surgery, DH is mainly used in aortic arch surgery, surgical treatment of pulmonary embolism, and acute type-A aortic dissection interventions. In surgery treating congenital defects, DH is used to assist aortic arch reconstructions, hypoplastic left heart syndrome interventions, and for multi-stage treatment of infants with a single heart ventricle during the neonatal period. However, it should be noted that a safe duration of circulatory arrest in DH for the central nervous system is 30 to 40 min at most and should not be exceeded to prevent severe neurological adverse events. Personalized therapy for the patient and adequate blood temperature monitoring, glycemia, hematocrit, pH, and cerebral oxygenation is a prerequisite and indispensable part of DH.

Brain protection in aortic arch aneurysm: antegrade or retrograde?

During open aortic arch repair, there is an interruption of cerebral perfusion and to prevent neurological sequelae, the hypothermic circulatory arrest has been established to provide sufficient brain protection coupled with adjuncts including retrograde and antegrade cerebral perfusion. To date, brain protection during open aortic arch repair is a contested topic as to which provides superior brain protection with little evidence existing to suggest supremacy of one modality over the other. This article reviews current literature reflecting on key and emerging studies in brain protection and their associated outcomes in patients undergoing open aortic arch surgery.

Hybrid repair of aortic arch aneurysms: a comprehensive review

Open total arch replacement (TAR) has become safer with refinements in cerebral protection techniques. The frequent extension of aortic arch aneurysms into the descending thoracic aorta customarily requires a two-staged conventional elephant trunk procedure, carrying relatively high mortality and morbidity risks and high rates of rupture in the interval between the two open surgeries. The technical demands and invasive nature of TAR has therefore precluded many high-risk patients from being surgical candidates for aneurysm repair. As a result, hybrid techniques and approaches to the aortic arch have become common since the adoption of thoracic endovascular aortic repair (TEVAR) and advancement in the commercial grafts that are available. The results of hybrid aortic arch repairs have been encouraging, though with higher rates of re-interventions than TAR and variable reported rates of stroke and spinal cord ischemia. The aim of this publication is to review the current literature on hybrid repair of aortic arch aneurysms.

Evaluation of cerebral circulation during retrograde perfusion by laser speckle flowgraphy

Laser speckle flowgraphy (LSFG) is an ophthalmologic equipment that qualitatively detects the blood flow of the optic nerve head, which is known to be related with cerebral microcirculation. LSFG can also measure the mean blur rate, which quantitatively calculates the blood flow. We aimed to assess the utility of LSFG in the evaluation of cerebral perfusion during aortic surgery under hypothermic circulatory arrest with retrograde and antegrade cerebral perfusion. Two patients underwent total arch replacement for aneurysm. The blood flow of the optic nerve head was monitored with LSFG and the mean blur rate value was measured during the surgery. The LSFG could detect the blood flow quantitatively in the optic nerve head during both retrograde and antegrade cerebral perfusion; and the value was correlated with rSO2 value.

[Paradoxical air embolism resulted in acute myocardial infarction and massive ischemic brain injury in a patient operated on in a sitting position]

Paradoxical air embolism (PAE) is a rare life-threatening complication when air emboli enter arteries of the systemic circulation and cause their occlusion. Here, we describe a clinical case of PAE developed during neurosurgery in a patient in the sitting position. PAE led to injuries to the cerebral blood vessels, coronary arteries, and lungs, which caused death of the patient. An effective measure for preventing PAE is abandoning surgery in the sitting position in favor of surgery in the prone position.