Spinal Cord Protection of Aorto-Iliac Bypass in Open Repair of Extent II and III Thoracoabdominal Aortic Aneurysm.

BACKGROUND: Spinal cord injury (SCI) is one of the serious complications of thoracoabdominal aortic aneurysm (TAAA) repair. Cardiopulmonary bypass (CPB) and left heart bypass (LHB) are well-established extracorporeal circulatory assistance methods to increase distal aortic perfusion and prevent spinal cord ischaemia in TAAA repair. Aorto-iliac bypass, a new surgical adjunct offering distal aortic perfusion without the need of complex perfusion skills, was developed as a substitute for CPB and LHB. However, its spinal cord protective effect is unknown. METHODS: The perioperative data of 183 patients who had elective open Crawford extent II and III TAAA repair at our aortic centre from July 2011 to May 2019 were retrospectively analysed. Spinal cord protection was compared between the aorto-iliac bypass group (n=106) and the extracorporeal circulatory assistance group (n=77 [65 CPB, 12 LHB]), and the risk factors for SCI in these patients were explored. RESULTS: Eleven (11) patients had postoperative SCI: five (6.5%) in the extracorporeal circulatory assistance group (four with CPB and one with LHB), and six (5.7%) in the aorto-iliac bypass group. The incidence of SCI was 6.0% (11/183 cases). There was no difference between the aorto-iliac bypass group and the extracorporeal circulatory assistance group (p=1.0), while operation time, proximal aortic clamp time, intercostal artery clamp time, and length of intensive care unit stay were all increased in the latter group. Multivariate logistic regression analysis showed that cerebrospinal fluid pressure (odds ratio [OR] 1.270; 95% confidence interval [CI] 1.092-1.478 [p=0.002]) and lowest haemoglobin on the first postoperative day (OR 0.610; 95% CI 0.416-0.895 [p=0.011]) were the independent predictors of SCI in TAAA repair. CONCLUSIONS: Spinal cord protection of aorto-iliac bypass is comparable to that of CPB and LHB in open TAAA repair.

Hybrid Left Heart Bypass Circuit for Repair of the Descending Aorta in an 8-kg Williams Syndrome Patient.

A 1-year old male patient with Williams syndrome and multiple prior interventions presented for surgical repair of his descending aorta (DA) through a left thoracotomy. Concerns for significant bleeding and spinal cord protection led the care team to consider a left heart bypass (LHB) circuit with options for pump sucker use, heat exchange capacity, and the possibility of converting to traditional cardiopulmonary bypass (CPB). A traditional CPB circuit with a roller-head arterial pump was assembled with a bypass line around the cardiotomy venous reservoir (CVR). Excluding the CVR with this line allowed for a closed LHB circuit. A second pump head was integrated to both recirculate the CVR volume and to serve as a means for controlled volume administration to the closed LHB circuit. Pump sucker return directed to the CVR could easily be transfused back to the patient. The patient was placed on the hybrid LHB circuit and cooled to 32°C. DA clamps were placed. Upper body dynamic blood pressure was managed for a target mean of 50 mmHg, the left atrial pressure (LAP) was maintained in the 5-7 mmHg range, and the nonpulsatile lower body blood pressure was targeted at 40-50 mmHg. Cerebral near-infrared spectroscopy (NIRS) helped guide volume and pressure management. The surgeons placed two long-segment patches on the DA, moving clamps as needed. The patient was rewarmed and separated from the hybrid LHB circuit after 82 minutes. Closed circuit LHB can be provided with a roller-head hybrid circuit incorporating an oxygenator for gas exchange, central cooling and warming, and arterial line filtration along with a CVR for pump sucker use and controlled transfusion to the patient.

Treatment of thoracoabdominal aortic aneurysm by prosthetic vessel replacement under left heart bypass. / å·¦å¿ƒè½¬æµä¸‹äººå·¥è¡€ç®¡ç½®æ¢æœ¯æ²»ç–—èƒ¸è ¹ä¸»åŠ¨è„‰ç˜¤.

OBJECTIVES: Thoracoabdominal aortic aneurysm (TAAA) prosthetic vessel replacement is one of the most complex operations in the field of cardiovascular surgery. The key to success of this operation is to prevent and avoid ischemia of important organs while repairing TAAA. This study aims to summarize and analyze the effect of prosthetic vessel replacement under left heart bypass in the treatment of TAAA. METHODS: Data of 15 patients with TAAA who underwent prosthetic vessel replacement under left heart bypass in Xiangya Hospital of Central South University were retrospectively analyzed. According to Crawford classification, there were 2 cases of type I, 8 cases of type II, 3 cases of type III, and 2 cases of type V. There were 14 cases of selective operation and 1 case of emergency operation. All operations were performed under left heart bypass, and cerebrospinal fluid drainage was performed before operation. Left heart bypass was established by intubation of left inferior pulmonary vein and distal abdominal aorta or left femoral artery. The thoracoabdominal aorta was replaced segment by segment. After aortic dissection, the kidneys were perfused with cold crystalloid renal protective solution, and the celiac trunk and superior mesenteric artery were perfused with warm blood. RESULTS: One patient with TAAA after aortic dissection of type A died. During the operation, straight blood vessels were used to repair TAAA, and the celiac artery branches were trimmed into island shape and anastomosed with prosthetic vessels. After the operation, massive bleeding occurred at the anastomotic stoma, then anaphylactic reaction occurred during massive blood transfusion, resulting in death. One patient suffered from paraplegia due to ischemic injury of spinal cord. The other patients recovered well and were discharged. The postoperative ventilation time was (16.5±13.8) h and the postoperative hospital stay was (10±4) d. The amount of red blood cell transfusion was (13±9) U. The patients were followed up for 2 months to 2 years, and the recovery was satisfactory. CONCLUSIONS: The effect of prosthetic vessel replacement under left heart bypass in the treatment of TAAA is good, which is worthy of clinical promotion.

Impact of Left Heart Bypass on Arterial Oxygenation During One-Lung Ventilation for Thoracic Aortic Surgery.

OBJECTIVE: The aim of this study was to reveal the mechanism of improved arterial oxygenation by measuring the changes in oxygenation before and after initiation of left heart bypass (LHB) during one-lung ventilation (OLV) for thoracic aortic surgery. DESIGN: Prospective, observational study. SETTING: Single-institution, private hospital. PARTICIPANTS: The study comprised 50 patients who underwent aortic surgery via a left thoracotomy approach with LHB circulatory support. INTERVENTIONS: Patients were ventilated using pure oxygen during OLV, and the ventilator setting was left unchanged during the measurement period. MEASUREMENTS AND MAIN RESULTS: The measurement of partial pressure of arterial oxygen (PaO2) was made at the following 4 time points: 2 minutes after heparin infusion (point 1 [P1]), 2 minutes after inflow cannula insertion through the left pulmonary vein (P2), immediately before LHB initiation (P3), and 10 minutes after LHB initiation (P4). The mean±standard deviation (mmHg) of PaO2 measurements at the P1, P2, P3, and P4 time points were 244±121, 250±123, 419±122, and 430±109, respectively, with significant increases between P1 and P3, P1 and P4, P2 and P3, and P2 and P4 (p<0.0001, respectively). No significant increase in PaO2 was seen between P1 and P2 or between P3 and P4. CONCLUSIONS: The improved arterial oxygenation during OLV in patients who underwent thoracic aortic surgery using LHB can be attributed to the insertion of an inflow cannula via the left pulmonary vein into the left atrium before LHB.

Intraoperative immunomodulation during left heart bypass in open thoracoabdominal aortic aneurysm repair.

Despite the technical innovations introduced in the previous decades, open thoracoabdominal aortic aneurysm repair still represents an enormous challenge for patients and surgeons. Logically, the systemic inflammatory response resulting from these massive operations appears considerable; however, the response has never been thoroughly investigated. In addition, intraoperative adjuncts to modulate the postoperative activation of the immune system have not yet been introduced into clinical practice. We report a case of intraoperative hemadsorption during open repair of a thoracoabdominal aortic aneurysm through the introduction of a CytoSorb device (CytoSorbents Corp) in the left heart bypass circuit. The technique appeared feasible and safe and probably contributed to the good clinical outcomes.

Distal Perfusion With Modified Centrifugal Pump Circuit in Thoracic and Thoracoabdominal Aortic Aneurysm Repair.

OBJECTIVE: The left heart bypass is currently the most frequent adjunct to provide distal aortic perfusion during aortic clamping. However, closed-circuits cannot respond to sudden hemodynamic fluctuations during aortic clamping which may lead to complications. In this report, we aim to give the technical aspects of reservoir-added centrifugal pump circuit system, its implementation and the clinical outcomes. METHODS: Between 2002 and 2020, the data of 35 patients underwent aortic aneurysm repair with the use of modified pump circuit were analyzed. The mean age was 53.4 years (range 24-73) and 91.4% of all was male. Preoperative demographics, intraoperative pump data and postoperative clinical outcomes were reported. RESULTS: Thoracoabdominal incision was used in 22 patients (62.9%) and cerebrospinal fluid (CSF) drainage catheter was placed in 15 patients (42.9%). The left inferior pulmonary vein for outflow and the left femoral artery for inflow cannulation were used preferably. Median duration of pump support was 50 mins (13-121) in the cohort. The median transfusion of red packed cells was 2 units. Renal failure was observed in two patients and permanent paraplegia in one patient. Only one patient died in the elective group (1/34) and one patient in the emergent. CONCLUSIONS: The reservoir-added centrifugal pump is an effective, practical, and flexible perfusion system which should be in the armamentarium of surgeons in order to solve difficult problems during open repair of descending and thoracoabdominal aortic aneurysms.

Left heart bypass for repair of aortic coarctation in children: Technical tips and pitfalls.

Spinal cord injury secondary to coarctation repair in children is a serious, though relatively uncommon, complication. Several measures have been proposed to minimize this risk, which seems to affect more older children than neonates and those with inadequate collateral circulation. Left heart bypass has been proposed as a protective strategy.

Asymptomatic Giant Aneurysm of the Arteria Lusoria Treated by Debranching and Aneurysmal Resection.

The aberrant right subclavian artery (ARSA, arteria lusoria) is the most common intrathoracic vascular anomaly, affecting up to 2% of the population. However, aneurysms of congenital anomalies are extremely unusual and often present with dysphagia, dysphonia, or dyspnea due to compression of the surrounding structures. We report a case of an asymptomatic 57-year-old male with chronic kidney disease who was incidentally found to have a large aneurysm of the ARSA on preoperative computed tomography for laparoscopic nephrectomy. Surgery is unequivocally warranted as these aneurysms are associated with a high risk of complications, including thrombosis, embolism, and rupture. We debranched the ARSA, followed by anastomosis to the right carotid artery through a right neck incision. Subsequently, aneurysmal resection was performed through left thoracotomy. The patient had an uneventful postoperative recovery and was asymptomatic during the follow-up.

The application of modular multifunctional left heart bypass circuit system integrated with ultrafiltration in thoracoabdominal aortic aneurysm repair.

Open thoracoabdominal aortic aneurysm (TAAA) repair is a complex and challenging operation with a high incidence of serious complications, and high perioperative mortality and morbidity. Left heart bypass (LHB) is a circulatory support system used to perfuse the distal aorta during TAAA operation, and the advantages of LHB include guaranteeing distal perfusion, reducing the use of heparin, and diminishing the risk of bleeding and postoperative neurological deficits. In China, the circuit for TAAA repair is deficient, and far from the perfusion requirements. We designed a modular multifunctional LHB circuit for TAAA repair. The modular circuit consisted of cannulation pipelines, functional consumables connection pipelines, and accessory pipelines. The accessory pipelines make up lines for selective visceral perfusion and kidney perfusion, suckers and rapid infusion. The circuit can be assembled according to surgical requirements. The ultrafilter and heat exchanger are integrated into the circuit to fulfill the basic demands of LHB. The LHB circuit also has pipelines for selective visceral perfusion to the celiac artery and superior mesenteric artery and renal perfusion pipelines. Meanwhile, the reserved pipelines facilitate the quick switch from LHB to conventional cardiopulmonary bypass (CPB). The reserved pipelines reduce the time of reassembling the CPB circuit. Moreover, the rapid infusion was integrated into the LHB circuit, which can rapid infusion when massive hemorrhage during the open procedures such as exposure and reconstruction of the aorta. The ultrafiltration can diminish the consequent hemodilution of hemorrhage and rapid infusion. A hemoperfusion cartridge also can be added to reduce the systemic inflammatory during operation. The circuit can meet the needs of LHB and quickly switch to conventional CPB. No oxygenator was required during LHB, which reduce the use of heparin and reduce the risk of bleeding. The heat exchanger contributes to temperature regulation; ultrafiltration, arterial filter, and rapid-infusion facilitated the blood volume management and are useful to maintain hemodynamic stability. This circuit made the assembly of the LHB circuit more easily, and more efficient, which may contribute to the TAAA repair operation performed in lower volume centers easily. 26 patients who received TAAA repair under the modular multifunctional LHB from January 2018-March 2022 were analyzed, and we achieved acceptable clinical outcomes. The in-hospital mortality and 30-day postoperative mortality were 15.4%, and the postoperative incidences of paraparesis (4%), stroke (4%), and AKI need hemodialysis (12%) were not particularly high, based on the limited patients sample size in short research period duration.

Left heart bypass versus circulatory arrest for open repair of thoracoabdominal aortic pathologies.

BACKGROUND: Most large-volume centres use left heart bypass (LHB) as their preferred organ protection strategy during repair of descending thoracic aortic (DTA) and thoracoabdominal aortic (TAA) pathologies. We investigate the use of hypothermic circulatory arrest (HCA) for similar pathologies and compare the outcomes of both. METHODS: A PubMed, Embase and Scopus search for studies in English on LHB versus HCA for repair of DTA and TAA pathologies published from inception till February 2020 was performed. Our analysis excluded studies without direct comparison of the two organ protection strategies. Clinical endpoints that were studied were 30-day mortality, post-operative stroke, spinal cord deficit, renal failure and respiratory failure. Random effects meta-analyses of the effect of the two strategies across all clinical endpoints were conducted. RESULTS: HCA is non-inferior to LHB across all clinical endpoints. In terms of 30-day mortality (odds ratio (OR) 1.19, 95% confidence interval (CI) 0.31-4.59, P = 0.14, I2 = 49%), stroke (OR 0.41, 95% CI 0.12-1.39, P = 0.97, I2 = 0%), spinal cord deficit (OR 0.56, 95% CI 0.22-1.45, P = 0.78, I2 = 0%), renal failure (OR 1.33, 95% CI 0.37-4.76, P = 0.98, I2 = 0%) and respiratory failure (OR 0.86, 95% CI 0.37-1.97, P = 0.16, I2 = 46%), there was no statistically significant difference between the two cohorts. CONCLUSION: Evidence is limited, but suggests that HCA alone provides adequate organ protection during repair of DTA and TAA pathologies, and has equivalent outcomes when compared to LHB.

Thoracoabdominal aneurysmectomy: Operative steps for Crawford extent II repair.

BACKGROUND: Open surgical repair remains the gold standard for treatment of thoracoabdominal aortic aneurysm (TAAA). Surgery aims to replace the whole length of the diseased distal aorta while protecting the spinal cord and the visceral organs to limit ischemia-related complications. The substantial associated surgical risks, including death, paraplegia, renal failure requiring permanent dialysis, and respiratory complications leading to prolonged intensive care unit stay, still outweigh the natural history of TAAA with conservative treatment. METHODS: We describe in detail our current approach to open extent II TAAA repair with a step-by-step illustration of the technique and the surgical adjuncts. RESULTS: We routinely perform left heart bypass with mild passive hypothermia (34°C), cerebrospinal fluid drainage, sequential aortic cross-clamping, monitoring of motor evoked potentials (MEPs) and cerebral, paraspinal, and lower limb oxygen saturation by near-infrared spectrometry, as well as selective visceral perfusion via the celiac and superior mesenteric arteries and renal protection with intermittent administration of Custodiol HTK (histidine-tryptophan-ketoglutarate) solution via the renal arteries. We advocate for individual branch reimplantation using a branched thoracoabdominal graft when possible, and we selectively reattach 1 or more pairs of the lower thoracic intercostal arteries and/or high lumbar arteries, even in the absence of a significant reduction in the MEPs signal. The distal anastomosis is usually constructed above the aortic bifurcation and occasionally to each iliac separately using a bifurcated graft. CONCLUSIONS: Favorable early outcomes and a durable TAAA repair can be achieved at experienced high-volume centers with standardized preoperative selection and multidisciplinary team-based intraoperative and postoperative management of these patients.

Current strategies of spinal cord protection during thoracoabdominal aortic surgery.

Despite improved survival rates after thoracoabdominal aortic aneurysm repairs, paraplegia remains a devastating complication with high incidence, ranging from 3 to 10%. Ischemic insults to the spinal cord are unavoidable during thoracoabdominal aortic aneurysm repairs. There is no single measure that can prevent paraplegia alone. A multimodality approach is required to minimize the ischemic insults during thoracoabdominal aortic aneurysm repairs and postoperative second hit to the spinal cord. Distal aortic perfusion is important to maintain the collateral network perfusion pressure, while cerebrospinal drainage allows to directly maintain the spinal cord perfusion. Reattachment of segmental arteries T8-T12 is encouraged to lower the incidence of both immediate and delayed paraplegia. Systemic arterial pressure should be maintained above 130 mmHg and cerebrospinal drainage should be continued until the second postoperative day, despite intact neurological status. In this article, we describe our current operative techniques and perioperative management in patients undergoing repairs of thoracoabdominal aortic aneurysm. A review of recent updates on spinal protection strategies is also reported.

Left heart bypass for thoracoabdominal aortic aneurysm repair: technical aspects.

There are different surgical techniques for providing circulatory support during the repair of thoracoabdominal aortic aneurysms. They all aim at reducing the afterload of the heart and the preservation of distal organ perfusion. Partial or total extracorporeal circulation with or without cooling and left heart bypass (LHB) are actually the most used surgical approaches. The objective of this study was to describe and comment on the technical aspects of the LHB. We briefly describe our results and put them into perspective based on the current literature.

Coronary Microcirculation During Left Heart Bypass with a Centrifugal Pump.

To estimate coronary microcirculation during left heart bypass (LHB), we performed an experimental comparison study of LHB and intraaortic balloon pumping (1ABP). LHB was performed with a BioMedicus BP-80 pump supporting half of the flow of cardiac output whereas the IABP was pumped in a 1:1 mode for cardiogenic shock in a swine model. Coronary circulations were analyzed by electromagnetic flowmeter, pulsed Doppler velocimeter, and laser Doppler flowmeter. Left ventricular end-diastolic pressure (LVEDP) was reduced significantly by LHB. Although there was no significant difference in epicardial flow between the LHB and IABP groups, endocardial flow was increased significantly by LHB. In the LHB group, the systolic reverse wave of the coronary velocity called a myocardial invalid circulation was reduced remarkably. There was a significant inverse correlation between endocardial flow and LVEDP. These results suggested that LHB was more effective for myocardial microcirculation than was IABP.

A New Supportive Method for Aortic Aneurysm Surgery: Centrifugal Left Heart Bypass Combined with an Oxygenator and a Heat Exchanger.

A new supportive method of centrifugal left heart bypass with oxygenation was performed in 25 patients and compared with standard left heart bypass in 45 patients. Femoro-femoral bypass was selected in another 6 patients because of the presence of a left atrial adhesion. Intraoperative complications related to standard left heart bypass, hypoxia, hypothermia, and ventricular fibrillation, were eliminated by using this method. This supportive method maintained good hemodynamics and improved the surgical result of extended thoracoabdominal aortic replacement. Hospital deaths decreased from 6.7% to 3.2%.

Tuberculous aortitis complicated with pseudoaneurysm formation in the descending thoracic aorta: a case report.

A 51-year-old male with sustained fever was diagnosed with military tuberculosis and tuberculous aortitis complicated with pseudoaneurysm formation at the proximal descending aorta. A follow-up computed tomography evaluation showed an increased size of the pseudoaneurysm in this area, suggestive of a contained rupture. Consequently, the patient underwent emergency excision and replacement of the aorta using a left heart bypass. The patient was discharged without postoperative complications on post-operative day 12. During the one-year follow-up period, the patient was free of any complications or recurrence of tuberculosis. We report a case of pseudoaneurysm of the descending aorta that was successfully surgically repaired.