Reoperative Aortic Arch Surgery under Mild Systemic Hypothermia: Two-Center Experience

Background The aim of the study was to assess the indications, surgical strategies, and outcomes after reoperative aortic arch surgery performed generally under mild hypothermia. Methods Ninety consecutive patients (60 males, mean age, 55 ± 16 years) underwent open reoperative aortic arch surgery after previous cardiac aortic surgery. The indications included chronic-progressive arch aneurysm (55.5%), chronic aortic dissection (17.8%), contained arch rupture (16.7%), and graft infection (10%). The reoperation was performed through a repeat sternotomy (96%) or clamshell thoracotomy (4%) using antegrade cerebral perfusion under mild systemic hypothermia (28.9 ± 2.5°C) in all except three patients. Results The surgery comprised hemiarch or total arch replacement in 41 (46%) and 49 (54%) patients, respectively. The distal extension included classic or frozen elephant trunk technique, each in 12 patients, and total descending aorta replacement in 4 patients. Operative mortality was 6 (6.7%) among all patients, with age identified as the only independent predictor of operative mortality (p = 0.05). Permanent and transient neurologic deficits occurred in 1% and 9% of the patients, respectively. Estimated survival at 8 years was 59 ± 8% with advanced heart failure predictive for late mortality (p = 0.014). Freedom from second reoperation or intervention on the aorta was 78 ± 6% at 8 years, with most of these events occurring downstream in patients with chronic degenerative aneurysms. Conclusion Aortic arch reoperations performed using antegrade cerebral perfusion under mild systemic hypothermia offer favorable operative outcomes with an exceptionally low rate of neurologic morbidity without any difference between hemiarch and complex arch procedures.

Artificial hibernation/life-protective state induced by thiazoline-related innate fear odors

Innate fear intimately connects to the life preservation in crises, although this relationships is not fully understood. Here, we report that presentation of a supernormal innate fear inducer 2-methyl-2-thiazoline (2MT), but not learned fear stimuli, induced robust systemic hypothermia/hypometabolism and suppressed aerobic metabolism via phosphorylation of pyruvate dehydrogenase, thereby enabling long-term survival in a lethal hypoxic environment. These responses exerted potent therapeutic effects in cutaneous and cerebral ischemia/reperfusion injury models. In contrast to hibernation, 2MT stimulation accelerated glucose uptake in the brain and suppressed oxygen saturation in the blood. Whole-brain mapping and chemogenetic activation revealed that the sensory representation of 2MT orchestrates physiological responses via brain stem Sp5/NST to midbrain PBN pathway. 2MT, as a supernormal stimulus of innate fear, induced exaggerated, latent life-protective effects in mice. If this system is preserved in humans, it may be utilized to give rise to a new field: “sensory medicine.”

Investigation of myocardial protection during pediatric CPB: Practical experience in 100 Chinese hospitals

Many measures have been proposed for myocardial protection in pediatric congenital heart surgeries, but little data is available for China. This study investigates myocardial protection strategies in pediatric cardiopulmonary bypass (CPB) throughout China. Online questionnaires were delivered to 100 hospitals in 27 provinces. The number of yearly on-pump pediatric cardiovascular surgeries in these hospitals varied greatly. About 91.0% of respondents believe that each surgery should have at least two perfusionists, while only 64.0% of hospitals actually met this requirement. For pediatric patients, crystalloid cardioplegia was more prevalent than blood-based cardioplegia. Histidine-tryptophan-ketoglutarate solution and St. Thomas crystalloid solution were dominant among crystalloid cardioplegia. Del Nido cardioplegia and St. Thomas blood-based cardioplegia ranked the top two in the popularity of blood-based cardioplegia. Dosages varied among different kinds of cardioplegia. In the choice of different cardioplegia, perfusionists mainly focused on myocardial protective effect and cost. Hypothermia of cardioplegia solution was maintained by ice buckets in 3/4 of the hospitals in this survey. In conclusion, the essence of myocardial protection management during pediatric CPB was cardiac arrest induced by cardioplegia under systemic hypothermia. However, there is no uniform standard for the type of cardioplegia, or dosages. Therefore, well-designed multicenter randomized controlled trials are warranted to provide tangible evidence for myocardial protection of cardioplegia in pediatric CPB.

Hypothermia for cardiogenic encephalopathy in neonates with dextro-transposition of the great arteries

OBJECTIVES Neonates with dextro-transposition of the great arteries (d-TGA) may experience rapid haemodynamic deterioration and profound hypoxaemia after birth. We report on d-TGA patients with severe acidosis, encephalopathy and their treatment with systemic hypothermia. METHODS This study is a single-centre retrospective cohort analysis of newborns with d-TGA. RESULTS Ninety-five patients (gestational age ≥35 weeks) with d-TGA and intended arterial switch operation were included. Ten infants (10.5%) with umbilical arterial blood pH > 7.10 experienced profound acidosis (pH < 7.00) within the first 2 h of life. Six of these patients displayed signs of encephalopathy and received therapeutic hypothermia. Apgar scores at 5 min independently predicted the development of neonatal encephalopathy during postnatal transition (unit Odds Ratio 0.17, 95% confidence interval 0.06–0.49, P = 0.001). Infants treated with hypothermia had a more severe preoperative course and required more often mechanical ventilation (100% vs 35%, P = 0.003), treatment with inhaled nitric oxide (50% vs 2.4%, P = 0.002) and inotropic support (67% vs 3.5%, P < 0.001), as compared to non-acidotic controls. The median age at cardiac surgery was 12 (range 6–14) days in cooled infants and 8 (4–59) days in controls (P = 0.088). Postoperative morbidity and total duration of hospitalization were not increased in infants receiving preoperative hypothermia. Mortality in newborns with severe preoperative acidosis was zero. CONCLUSIONS Newborn infants with d-TGA have a substantial risk for profound acidosis during the first hours of life. Systemic hypothermia for encephalopathic patients may delay corrective surgery without compromising perioperative outcomes.

Single-Stage Treatment of Aneurysm of the Distal Aortic Arch and Proximal Descending Aorta Using the Frozen Elephant Trunk Procedure. Case Report

Aneurysms of the thoracic aorta involving the distal arch and the proximal descending aorta have traditionally been treated with two open procedures. During the first stage, the aortic arch pathology has been addressed through a median sternotomy. Several weeks or months later, a second stage followed and included completing the repair of the descending aorta through a lateral thoracotomy.We, herein, report a single stage repair of an aneurysm involving the distal aortic arch and the proximal descending aorta using the frozen elephant trunk operative technique. Vascular hybrid stent graft prosthesis, specifically designed for treatment of extensive aortic aneurysms, has been used to replace the arch component and exclude the descending aorta component of the aneurysm through a median sternotomy, using bilateral antegrade cerebral perfusion and mild systemic hypothermia for intraoperative organ protection.

Minimally Invasive Aortic Arch Repair: Technical Considerations and Mid-Term Outcomes

Background: Reports of minimal invasive aortic arch surgery are scarce. We reviewed our experience with minimal access aortic arch surgery performed through an upper mini-sternotomy, with emphasis on details of operative technique and early and mid-term outcomes. Methods: The medical records of 123 adult patients (mean age 66 ± 12 years), who underwent primary elective minimal access aortic arch surgery in two aortic referral centers, were reviewed. The most common indication was degenerative aortic arch aneurysm in 92 (75%) patients. Standard operative and organ protection techniques used in all patients were upper mini-sternotomy, uninterrupted antegrade cerebral perfusion, and moderate systemic hypothermia (27.4 ± 1°C). Results: Sixty-eight (55%) patients received partial aortic arch replacement; the remaining 55 (45%) patients received total arch replacement, further extended with either a frozen elephant trunk in 43 (35%) patients or a conventional elephant trunk procedure in nine (7%) patients. No conversion to full sternotomy was required. New permanent renal failure occurred in one (0.8%) patient, stroke in two (1.6%), and spinal cord injury in four (3.3%) patients. Early mortality was observed in four (3.3%) patients. At five years, survival was 80 ± 6% and freedom from reoperation was 96 ± 3%. Conclusion: Minimal invasive aortic arch repair through an upper mini-sternotomy can be safely performed, with early and mid-term outcomes well comparable to series performed through a standard median sternotomy.

Acute peripheral ischemia in healthy female patient: an indirect and unanticipated diagnosis of spontaneous thrombus in the aortic arch

Background In this case we discuss the management of a pediculated floating thrombus in the aortic arch which led to peripheral embolization and acute ischemia oft he left leg. Case presentation A healthy 46 year old female patient presented with pain in her left leg and progressive numbness. Computed Tomography Angiography (CTA) showed an acute ischemia of the left leg (Rutherford 2 B) with a 2 cm thrombus distal of the aortic bifurcation. Emergency operation with embolectomy, selective thrombembolectomy and patch plasty on the tibioperoneal trunk and local lysis was performed. As part of a further diagnostic examination a thoracic CT scan has been performed revealing a pediculated-floating 2 cm thrombus in the aortic arch. Four days after the initial operation thrombus excision via a minimally invasive access way has been performed. After initiation of the extracorporeal circulation, selective unilateral antegrade cerebral perfusion has been established in mild (30–32 °C) systemic hypothermia. Patients postoperative course was uneventful. Histological evaluation of the mass demonstrated thrombotic material without evidence of infection or malignacy. Conclusion A pediculated spontaneous thrombus may develop in aortic arch in patients without traditional risk factors or family history of embolic events. Two stage operation was feasible and safe.

PROTECTION OF CENTRAL AND PERIPHERAL ORGANS IN AORTIC SURGERY

The introduction into clinical practice of hypothermic circulatory arrest, both in the non−perfusion version and with an artificial circulation, was the beginning of active use of systemic hypothermia as an effective element of cerebral and visceral protection during combined cardiac surgeries, including in aorta pathology. To evaluate ways of protecting visceral organs and spinal cord, namely the "no perfusion" technique with drainage of cerebrospinal fluid, lateral aortic compression, left−atrial−femoral bypass, deep hypothermia with cardiac arrest, i.e. hypothermic circulatory arest, bypass grafting, artificial blood circulation and moderate hypothermia in surgery for acute aortic syndrome the results of treatment of the patients with acute bundle aortic aortic abdominal localization were analyzed. There was characterized the proposed and implemented in practice original method of protection, consisting in an access to aorta, which is pressed above the aneurysm at the level of bifurcation, and selective perfusion into the mouth of vessels supplying the internal organs with a custodiol solution with a temperature of 3−4°. All the patients with combined occlusion−stenotic lesions of different arterial pools have aortic prostheses with the inclusion of visceral arteries into bloodstream in different variants. The tendency of the more favorable post−surgery period in the patients to whom the implemented methods of protection were applied. Key words: aortic aneurysm, surgical treatment, organ protection.