Increased risk for the development of postoperative severe hypoxemia in obese women with acute type a aortic dissection

Case report: Prone positioning in the improvement of severe post-operative hypoxia following aortic dissection

Postoperative hypoxemia after aortic dissection surgery presents a considerable clinical challenge, and acute respiratory distress syndrome (ARDS) is a common etiology. Prone positioning treatment has emerged as a potential intervention for improving respiratory function in this context. We report the case of a 27-year-old male who developed severe hypoxemia complicated by pulmonary embolism after aortic dissection surgery. He was diagnosed with postoperative hypoxemia combined with pulmonary embolism following aortic dissection. His respiratory status continued to deteriorate despite receiving standard postoperative care, thereby necessitating an alternative approach. Implementation of prone positioning treatment led to a substantial amelioration in his oxygenation and overall respiratory health, with a consistent hemodynamic state observed throughout the treatment. This technique resulted in significant relief in symptoms and improvement in respiratory parameters, facilitating successful extubation and, ultimately, discharge. This case underlines the possible efficacy of prone positioning therapy in managing severe hypoxia complicated by pulmonary embolism following aortic dissection surgery, warranting more thorough research to explore the potential of this treatment modality.

Study on risk factors and treatment strategies of hypoxemia after acute type a aortic dissection surgery

Acute type A aortic dissection is a life-threatening cardiovascular disease characterized by rapid onset and high mortality. Emergency surgery is the preferred and reliable treatment option. However, postoperative complications significantly impact patient prognosis. Hypoxemia, a common complication, poses challenges in clinical treatment, negatively affecting patient outcomes and increasing the risk of mortality. Therefore, it is crucial to study and comprehend the risk factors and treatment strategies for hypoxemia following acute type A aortic dissection to facilitate early intervention.

The impact of prolonged mechanical ventilation after acute type A aortic dissection repair

OBJECTIVE

Patients with type A aortic dissection have increased resource use. The objective of this study was to describe the relationship between prolonged mechanical ventilation and longitudinal survival in patients undergoing type A aortic dissection repair.

METHODS

We conducted a retrospective analysis of patients with type A aortic dissection undergoing repair from 2010 to 2018; Kaplan-Meier function and adjusted Cox regression analysis were used to compare in-hospital mortality and longitudinal survival accounting for time on mechanical ventilatory support.

RESULTS

A total of 552 patients were included. The study population was divided into 12 hours or less (n = 291), more than 12 to 24 or less hours (n = 101), more than 24 to 48 hours or less (n = 60), and more than 48 hours (n = 100) groups. Patients within the 12 or less hours group were the youngest (60.0 vs 63.5 years vs 63.6 vs 62.8 years; P = .03) and less likely to be female (31.6% vs 43.6% vs 46.7% vs 56.0%; P < .001). On the other hand, the more than 48 hours group presented with malperfusion syndrome at admission more often (24.4% vs 29.7% vs 28.3% vs 53.0%; P < .001) and had longer cardiopulmonary and ischemic times (P < .05). In-hospital mortality was significantly higher in the more than 48 hours group (5.2% vs 6.9% vs 3.3% vs 30.0%; P < .001). Multivariable analysis demonstrated worse longitudinal survival for the 24 to 48 hours group (hazard ratio, 1.94, confidence interval, 1.10-3.43) and more than 48 hours ventilation group (hazard ratio, 2.25, confidence interval, 1.30-3.92).

CONCLUSIONS

The need for prolonged mechanical ventilatory support is prevalent and associated with other perioperative complications. More important, after adjusting for other covariates, prolonged mechanical ventilation is an independent factor associated with increased longitudinal mortality.

Investigation of the Association between Bilateral Selective Anterograde Cerebral Perfusion and Postoperative Ischemic Stroke in Obese Patients with Emergency Surgery for Acute Type A Aortic Dissection

Background and objectives: The relationship between cerebral perfusion and new postoperative ischemic stroke in obese patients is not well defined. The aim of this study was to investigate the association between selective bilateral anterograde cerebral perfusion and new postoperative ischemic stroke in obese patients with emergency surgery for acute type A aortic dissection. Materials and methods: A total of 292 patients with emergency surgery for acute type A aortic dissection were included in this study. Patients with hemorrhagic stroke or ischemic stroke with severe neurological dysfunction at admission that were not candidates for surgery; patients who died in the first 48 h after intensive care admission and patients with incomplete medical records were excluded. Results: The mean age was 59.42 ± 10.68 years and the mean Euroscore was 9.12 ± 1.63. Obesity was present in 76.4%, the incidence of new postoperative ischemic stroke was 27.5%, and the postoperative mortality rate was 26.7%. The mean cardiopulmonary bypass time was 206.81 ± 75.48 min, the aortic cross-clamp time was 118.2 ± 46.42 min, and 90% of cases required cerebral perfusion. The mean cerebral perfusion time was 30.8 ± 24.41 min. Obese patients had a higher frequency of in-hospital death (p = 0.009), smoking (p = 0.036), hypertension (p = 0.023), left common carotid artery dissection (p < 0.001), right common carotid artery dissection (p = 0.029), femoral artery cannulation (p = 0.026), aortic root replacement (p = 0.009), aortic valve replacement (p = 0.005) and early reintervention for bleeding (p = 0.004). Using logistic regression, selective bilateral anterograde cerebral perfusion over 40 min in obese patients was independently associated with new postoperative ischemic stroke (OR = 2.35; 95%CI = 1.36-4.86; p = 0.021). Conclusions: A patient-tailored strategy for cerebral perfusion should be considered in obese patients, considering the high atheromatous burden of the supra-aortic vessels in these patients and the potential risk of atheromatous embolization associated with this technique.

Perioperative oxygenation impairment related to type a aortic dissection

Type A aortic dissection (TAAD) is a life-threatening disease with high mortality and poor prognosis, usually treated by surgery. There are many complications in its perioperative period, one of which is oxygenation impairment (OI). As a common complication of TAAD, OI usually occurs throughout the perioperative period of TAAD and requires prolonged mechanical ventilation (MV) and other supportive measures. The purpose of this article is to review the risk factors, mechanisms, and treatments of type A aortic dissection-related oxygenation impairment (TAAD-OI) so as to improve clinicians' knowledge about it. Among risk factors, elevated body mass index (BMI), prolonged extracorporeal circulation (ECC) duration, higher inflammatory cells and stored blood transfusion stand out. A reduced occurrence of TAAD-OI can be achieved by controlling these risk factors such as suppressing inflammatory response by drugs. As for its mechanism, it is currently believed that inflammatory signaling pathways play a major role in this process, including the HMGB1/RAGE signaling pathway, gut-lung axis and macrophage, which have been gradually explored and are expected to provide evidences revealing the specific mechanism of TAAD-OI. Numerous treatments have been investigated for TAAD-OI, such as nitric oxide (NO), continuous pulmonary perfusion/inflation, ulinastatin and sivelestat sodium, immunomodulation intervention and mechanical support. However, these measures are all aimed at postoperative TAAD-OI, and not all of the therapies have shown satisfactory effects. Treatments for preoperative TAAD-OI are not currently available because it is difficult to correct OI without correcting the dissection. Therefore, the best solution for preoperative TAAD-OI is to operate as soon as possible. At present, there is no specific method for clinical application, and it relies more on the experience of clinicians or learns from treatments of other diseases related to oxygenation disorders. More efforts should be made to understand its pathogenesis to better improve its treatments in the future.

Risk factors for intraprocedural hypoxemia in patients with acute cerebral ischemia treated with vascular intervention and its impact on prognosis: A retrospective cohort study

BACKGROUND

Acute cerebral infarction (ACI) is one of the most common ischemic cerebrovascular diseases in neurology, with high morbidity, mortality, and disability. Early thrombolytic treatment of ACI has significant efficacy, but intraprocedural complications of hypoxemia can significantly reduce the efficacy. This study aims to analyze the risk factors for intraprocedural hypoxemia in patients with ACI, so as to take effective measures in advance to reduce the likelihood of adverse patient outcomes.

METHODS

We retrospectively analyzed a total of 238 patients with ACI treated with vascular interventions from May 2017 to May 2022. To assess and collate the patients' characteristics, factors associated with the development of intraprocedural hypoxemia. The independent risk factors for the development of intraprocedural hypoxemia were analyzed by binary logistic regression.

RESULTS

A total of 238 patients were included in this study. Of these, intraprocedural hypoxemia occurred in 89 (37.4%). The results showed that old age (odds ratio [OR] = 2.666, P = 0.009), obesity (OR = 3.029, P = 0.003), smoking history (OR = 2.655, P = 0.010), preoperative oxygen saturation (SpO2) (OR = 0.001, P = 0.042), preoperative C-reactive protein (OR = 1.216, P = 0.002), and time from puncture to vascular recanalization (OR = 1.135, P = 0.000) were independent risk factors for intraprocedural hypoxemia in patients. The prognosis of the patients was assessed according to the modified Rankin scale, and the prognosis of the nonhypoxemia group was significantly better than that of the hypoxemia group. Regression analysis showed that intraprocedural hypoxemia (OR = 0.360, P = 0.001), postoperative lower extremity vein thrombosis (OR = 0.187, P = 0.018), hydrocephalus (OR = 0.069, P = 0.015), intracranial hemorrhage (OR = 0.116, P = 0.002), and reocclusion (OR = 0.217, P = 0.036) were independent risk factors for poor prognosis.

CONCLUSIONS

Currently, intravascular hypoxemia in patients with ACI has a serious impact on prognosis. Clinical work should attach great importance to the clinical characteristics of patients, identify relevant risk factors, and aggressively take personalized therapeutic actions to improve patients' prognosis.

Postoperative hypoxemia for patients undergoing Stanford type A aortic dissection

Clinically, it is widely recognized that surgical treatment is the preferred and reliable option for Stanford type A aortic dissection. Stanford type A aortic dissection is an emergent and serious cardiovascular disease characterized with an acute onset, poor prognosis, and high mortality. However, the incidences of postoperative complications are relatively higher due to the complexity of the disease and its intricate procedure. It has been considered that hypoxemia, one of the most common postoperative complications, plays an important role in having a worse clinical prognosis. Therefore, the effective intervention of postoperative hypoxemia is significant for the improved prognosis of patients with Stanford type A aortic dissection.

High preoperative bradykinin level is a risk factor for severe postoperative hypoxaemia in acute aortic dissection surgery

NEW FINDINGS

What is the central question of this study? Hypoxaemia can lead to increased postoperative mortality in patients: what are the independent risk factors for severe hypoxaemia after acute Stanford type A aortic dissection? What is the main finding and its importance? Severe postoperative hypoxaemia was found in 36.4% of patients, and it was determined that high preoperative bradykinin levels and increased BMI were independent predictors of severe postoperative hypoxaemia in patients with acute Stanford type A aortic dissection. For obese patients with high preoperative bradykinin levels, more attention should be paid to preventing severe postoperative hypoxaemia.

ABSTRACT

Severe hypoxaemia after cardiac surgery is associated with serious complications and a high risk of mortality. The purpose of this study is to investigate the independent risk factors of severe postoperative hypoxaemia in patients with acute Stanford type A aortic dissection. We collected 77 patients with acute Stanford type A aortic dissection who underwent surgical treatment. The primary outcome was severe postoperative hypoxaemia (PaO2 /FiO2  ≤ 100 mmHg), and a multivariate logistic regression analysis was performed to assess the independent predictors of risk for this. A mixed-effects analysis of variance model and a receiver operating characteristic (ROC) curve were generated to evaluate the predictive probabilities of risk factors for severe postoperative hypoxaemia. A total of 36.4% of patients developed severe postoperative hypoxaemia. The multivariate logistic regression analysis identified high preoperative bradykinin level (odds ratio (OR) = 55.918, P < 0.001) and increased body mass index (BMI; OR = 1.292, P = 0.032) as independent predictors of severe postoperative hypoxaemia in patients with acute Stanford type A aortic dissection. The mixed-effect analysis of variance model and ROC curve indicated that high preoperative bradykinin level and BMI were significant predictors of severe postoperative hypoxaemia (area under the ROC curve = 0.834 and 0.764, respectively). High preoperative bradykinin levels and obesity were independent risk factors for severe postoperative hypoxaemia in patients with acute Stanford type A aortic dissection. For obese patients with high levels of bradykinin before surgery, clinicians should actively take measures to block bradykinin-mediated inflammatory reactions.

Association of preoperative monocyte/lymphocyte ratio with postoperative oxygenation impairment in patients with acute aortic syndrome

BACKGROUND

Postoperative oxygenation impairment represents a common complication in patients with the acute aortic syndrome (AAS). The study aimed to explore the relationship between inflammatory indicators and AAS patients with oxygenation impairment after operation.

METHODS

In this study, 330 AAS patients who underwent surgery were enrolled and divided into 2 groups based on postoperative oxygenation impairment (non-oxygenation impairment group and oxygenation impairment group). Regression analysis was performed to assess the relationship between inflammatory indicators and postoperative oxygenation impairment. A smooth curve and interaction analysis were further conducted. Stratified analysis was used according to preoperative monocyte/lymphocyte ratio (MLR) (Tertiles).

RESULTS

Multivariate analysis showed that preoperative MLR was independently related to oxygenation impairment after surgery in AAS patients (OR, 95% CI, P: 2.77, 1.10-7.00, 0.031). The smooth curve indicated the risk of postoperative oxygenation impairment was higher with the elevated preoperative MLR. Interaction analysis revealed that patients with AAS with high preoperative MLR who had coronary artery disease (CAD) had a higher risk of oxygenation impairment after operation. Moreover, stratified analysis was performed according to baseline MLR (Tertiles), and a higher baseline MLR level in AAS patients was correlated with a lower arterial oxygen tension (P_aO2) / inspiratory oxygen fraction (F_iO2) ratio perioperatively.

CONCLUSIONS

In AAS patients, preoperative MLR level was independently related to postoperative oxygenation impairment.

Study on the relationship among typhoon, climate change, and acute Stanford type A aortic dissection in southern of Zhejiang in China

BACKGROUND

The aim of this study was to investigate the relationship between typhoon, climate change, and acute Stanford type A aortic dissection (TAAD) in southern of Zhejiang Province in China.

METHOD

371 patients with TAAD were admitted to three hospitals (the aortic dissection center) in southern of Zhejiang Province, China from January 2015 to December 2020, and data were retrospectively collected, the data included (1) the number of patients admitted in different months and seasons, (2) daily meteorological data in southern of Zhejiang Province, and (3) typhoon information were retrospectively analyzed.

RESULTS

The number of TAAD occurred in winter was the highest and in summer was the lowest. The incidence of TAAD was correlated with minimum temperature, maximum wind speed, mean wind speed, and water vapor pressure (P < 0.05). Maximum wind speed (RR 0.37; 95% CI 0.17 to 0.80, P = 0.01) and water vapor pressure (RR 0.96; 95% CI 0.92 to 1, P = 0.03) were the protective factor. The occurrence incidence of TAAD under the influence of typhoon climate was less than that during the period not affected by typhoon (P < 0.05).

CONCLUSION

There was a correlation between typhoon, climate change, and the occurrence of TAAD in southern Zhejiang Province. Wind speed, vapor pressure, and typhoon may be protective factors.

Experience of the Postoperative Intensive Care Treatment of Stanford Type A Aortic Dissection

OBJECTIVE

To summarize the experience of the postoperative intensive care treatment of Stanford type A aortic dissection (STAAD) following Sun's procedure.

METHODS

A total of 124 patients with STAAD who underwent Sun's procedure from January 2014 to December 2021 at the General Hospital of Ningxia Medical University were retrospectively analyzed. All patients were admitted to the cardiac surgery intensive care unit (ICU) after surgery. According to the perioperative characteristics of the patients with STAAD, intensive care treatment was given to actively prevent the occurrence of postoperative complications.

RESULTS

In all the cases enrolled in this study, the causes of aortic dissection comprised hypertension (105 cases), trauma (six cases), Marfan's syndrome (six cases), and aorto-arteritis (seven cases). The history of past illnesses comprised hypertension (105 cases), coronary disease (25 cases), diabetes mellitus (16 cases), and chronic obstructive pulmonary disease (six cases). There were some preoperative complications, such as cardiac insufficiency, acute liver insufficiency, acute renal insufficiency, pleural effusion, pericardial effusion, pulmonary infection, lower limb ischemia, mesenteric arterial embolism, and digestive tract hemorrhage. The average cardiopulmonary bypass time was 186 ± 32.1 min, the aortic clamp time was 74 ± 12.8 min, the deep hypothermic circulatory arrest time was 21 ± 2.6 min, and the mechanical ventilation time was 34 ± 2.8 h. The average ICU and hospital residence times were 7 ± 1.6 days and 12 ± 3.6 days, respectively. Postoperative complications comprised hypoxemia (34 cases), pulmonary infections (22 cases), tracheostomy (four cases), cerebral hemorrhage (four cases), cerebral infarction (four cases), transient delirium (eight cases), secondary thoracotomies due to bleeding (two cases), alimentary tract hemorrhage (eight cases), and acute renal insufficiency (38 cases). There was no occurrence of hoarseness or chylothorax. There were 15 cases of death, and the total mortality rate was 12.1%. In four cases, the cause of death was one postoperative complication (3.2%), and in 11 cases, the cause of death was multiple postoperative complications (8.9%). The other patients were discharged from the hospital with a good prognosis for full recovery.

CONCLUSION

Postoperative intensive care treatment was an important part of the successful surgical treatment of STAAD.

Risk factors and long-term prognosis for postoperative hypoxemia in patients with acute type A aortic dissection: A retrospective observational study

Hypoxemia is 1 of the most common complications in the patients with acute Type A aortic dissection (ATAAD). This study aimed to summarize the risk factors, management strategies and long-term prognosis for postoperative hypoxemia in ATAAD patients. Baseline characteristics and clinical data of all the patients were collected. Patients were divided into 2 groups according to the PaO2/FiO2 after surgery: Hypoxemia group (n = 142) and Non-hypoxemia group (n = 68). The differences in gender, age, body mass index, operation time, cardiopulmonary bypass (CPB) time, aortic cross-clamping time, deep hypothermic circulatory arrest time, preoperative PaO2/FiO2, postoperative PaO2/FiO2, PaO2/FiO2 before extubating, time of mechanical ventilation, length of intensive care unit stay, length of hospital stay, in-hospital mortality, and overall mortality were compared between the 2 groups. The incidence of postoperative hypoxemia in this study was 67.6% (142/210). body mass index (26.4 ± 3.8 vs 24.4 ± 3.3kg/m2, P < .001) in the hypoxemia group were markedly higher and CPB time (196.3 ± 41.0 vs 181.0 ± 37.3 minutes, P = .010) in the hypoxemia group were significantly longer than those in the non-hypoxemia group. While preoperative PaO2/FiO2 (229.7 ± 91.4 vs 299.7 ± 101.2mmHg, P < .001) was significantly lower than those in the non-hypoxemia group. In the hypoxemia group, PaO2/FiO2 before extubating was significantly higher than that after operation, and the difference was significant. Logistic regression analysis showed that overweight (odds ratio [OR]: 1.113, P = .030), CPB time (OR: 1.009, P = .043) and preoperative PaO2/FiO2 (OR: 0.994, P = .001) were independent risk factors for postoperative hypoxemia. Further follow-up results showed no significant difference in long-term mortality between the 2 groups. Logistic regression analysis revealed that PaO2/FiO2 before extubating (OR: 0.985, P < .001), paraplegia (OR: 10.994, P = .019), acute renal failure (OR: 12.590, P < .001), re-operation (OR: 4.721, P = .014) and re-admission to intensive care unit (OR: 13.727, P = .001) were independent risk factors for long-term mortality. Our results showed that overweight and prolonged CPB time were risk factors for postoperative hypoxemia in ATAAD patients. While PaO2/FiO2 before extubating were independent risk factors for long-term mortality, indicating that active correction of hypoxemia and maintain a higher PaO2/FiO2 before extubating may help to improve the prognosis of the ATAAD patients.

Impact of body mass index on postoperative oxygenation impairment in patients with acute aortic syndrome

Objective: Oxygenation impairment is a common complication of acute aortic syndrome (AAS) patients after surgical repair. The aim of this study is to identify the relationship between body mass index (BMI) and the risk of postoperative oxygenation impairment in AAS patients.

Methods: A total of 227 consecutive patients who were diagnosed as AAS and underwent surgical repair were recruited. They were divided into two groups based on the postoperative oxygenation impairment (non-oxygenation impairment group and oxygenation impairment group). Logistic regression was conducted to evaluate the association between BMI and the risk of oxygenation impairment after surgery. Dose-response curve and subgroup analysis were used to test the reliability of the results of regression analysis. A meta-analysis was then performed to further confirm these results using Pubmed, Embase, and Web of Science databases.

Results: For the retrospective study, a significant association was observed after adjusting for a series of variables. BMI was significantly correlated with postoperative oxygenation impairment in patients with AAS (OR, 95% CI, P: 1.27, 1.17–1.46, 0.001). Compared with the normal weight group (18.5 kg/m² ≤ BMI <23.0 kg/m²), patients with excessive BMI were at a higher risk of oxygenation impairment for the overweight group (23.0 kg/m² ≤ BMI <25 kg/m²) and obesity group (BMI ≥25 kg/m²) (OR, 95% CI, P: 4.96, 1.62–15.15, 0.005; 9.51, 3.06–29.57, <0.001). The dose-response curve showed that the risk of oxygenation impairment after surgery increased with the increased BMI. Besides, subgroup analysis showed that AAS patients who have an excess weight with a TNF-α ≥ 8.1 pg/ml carried an excess risk of postoperative oxygenation impairment. For the meta-analysis, the pooled result also indicated that AAS patients with high BMI had a significantly increased risk of oxygenation impairment after surgery (OR, 95% CI, P: 1.40, 1.18–1.66, 0.001).

Conclusion: Excessive BMI was an independent risk factor for AAS with postoperative oxygenation impairment.

Nomogram and risk calculator for severe hypoxemia after heart valve surgery

Background

Hypoxemia is a very common issue in patients undergoing heart valve surgery (HVS), related to poor clinical outcomes. However, studies on severe hypoxemia (SH) after HVS have not been reported. The aims of this study were to identify predictors for SH in patients undergoing HVS and to develop and validate a risk prediction model.

Methods

Patients undergoing HVS between 2016 and 2019 in a cardiovascular center were enrolled and were assigned to training and validation sets by a 7:3 ratio. Based on whether patients developed SH, they were divided into two groups. By univariate and multivariate analysis, predictors for SH were identified. Based on the predictors and logistic rule, a nomogram and a risk calculator were generated. The model was evaluated using calibration, discrimination and clinical utility.

Results

The incidence rates of SH, moderate hypoxemia and mild hypoxemia were respectively 2.4, 23.9, and 58.2%. By multivariate analysis, seven independent risk factors for SH after HVS were identified, including body mass index, chronic obstructive pulmonary disease, renal insufficiency, white blood cell count, serum globulin, cardiopulmonary bypass time, and surgical types. The logistic model demonstrated satisfactory discrimination, calibration and clinical utility in both the training and validation sets. A nomogram and a risk calculator based on the logistic model were generated for easy application. Risk stratification was performed and three risk intervals were defined according to the nomogram and clinical practice. In addition, compared to patients without SH, patients with SH had significantly poorer clinical outcomes.

Conclusions

Postoperative hypoxemia was prevalent after HVS, related to poor clinical outcomes. A logistic model including seven independent predictors for SH after HVS were established and validated, which demonstrated satisfactory discrimination, calibration and clinical utility. The results of this study may provide help to individualized risk assessment, early prevention and perioperative management.

Incidence, Risk Factors, and Outcomes of Severe Hypoxemia After Cardiac Surgery

Background

Hypoxemia is common in patients undergoing cardiac surgery, however, few studies about severe hypoxemia (SH) after cardiac surgery exist. The objectives of this study were to clarify the incidence, risk factors, and outcomes of SH after cardiac surgery.

Methods

Patients undergoing cardiac surgery from 2016 to 2019 in a single center were enrolled and were divided into two groups based on whether postoperative SH developed. Independent risk factors for SH were identified by univariate and multivariate analysis. Model selection statistics were applied to help determine the most parsimonious final model.

Results

Severe hypoxemia developed in 222 of the 5,323 included patients (4.2%), was associated with poorer clinical outcomes. Six independent risk factors for SH after cardiac surgery were identified by multivariate analysis, such as surgical types, white blood cell (WBC) count, body mass index (BMI), serum albumin, cardiopulmonary bypass (CPB) time, and intraoperative transfusion of red blood cells (RBCs). After comprehensively considering the discrimination, calibration, and simplicity, the most appropriate and parsimonious model was finally established using four predictors, such as WBC count, BMI, CPB time, and intraoperative transfusion of RBCs. A nomogram and a web-based risk calculator based on the final model were constructed to facilitate clinical practice. Patients were stratified into three risk groups based on the nomogram and clinical practice.

Conclusion

Severe hypoxemia was common after cardiac surgery and was associated with poorer clinical outcomes. A parsimonious final model with good discrimination, calibration, and clinical utility was constructed, which may be helpful for personalized risk assessment and targeted intervention.

Metabolic syndrome and its components are associated with hypoxemia after surgery for acute type A aortic dissection: an observational study

Background

The aim of this study was to explore whether or to what extent metabolic syndrome (METs) and its components were associated with hypoxemia in acute type A aortic dissection (ATAAD) patients after surgery.

Methods

This study involved 271 inpatients who underwent surgery. Demographic and clinical data were collected. Subgroup analysis, mixed model regression analysis, and receiver operating characteristic (ROC) curve analysis were performed, and a scoring system was evaluated.

Results

The 271 inpatients were assigned to the hypoxemia group (n = 48) or no hypoxemia group (n = 223) regardless of METs status. Compared to the no hypoxemia group, the hypoxemia group had a higher incidence of METs. Hypoxemia was present in 0%, 3.7%, 19.8%, 51.5%, 90.0% and 100% in the groups of individuals who met the diagnostic criteria of MetS 0, 1, 2, 3, 4 and 5 times, respectively. In the multivariable logistic regression analysis, BMI quartile was still a risk factor for hypoxemia after adjustment for other risk factors. After adjustment for potential confounding factors, METs was an independent risk factor for hypoxemia in several models. After assigning a score for each METs component present, the AUCs were 0.852 (95% CI 0.789–0.914) in all patients, 0.728 (95% CI 0.573–0.882) in patients with METs and 0.744 (95% CI 0.636–0.853) in patients without METs according to receiver operating characteristic analysis.

Conclusions

METs, especially body mass index, confers a greater risk of hypoxemia in ATAAD after surgery.

Zone proximalization in frozen elephant trunk: what is the optimal zone for open intervention? A systematic review and meta-analysis

INTRODUCTION

The treatment of complex aortic lesions involving the ascending, arch, and proximal descending aorta, remains challenging for surgeons despite the evolution of surgical techniques and aortic prostheses over decades. The frozen elephant trunk (FET) approach offers a one-stage repair of this entity of aortic pathologies. The main scope of this systematic review and meta-analysis is to evaluate the clinical outcomes and effectiveness of FET.

EVIDENCE ACQUISITION

In a systematic review, multiple electronic databases including EMBASE, Scopus, and PubMed/MEDLINE were searched from inception to June 2021 to identify relevant studies reporting on outcomes of total arch replacement (TAR) with FET.

EVIDENCE SYNTHESIS

Eighty-five studies met inclusion criteria, encompassing 10960 patients. Meta-analysis was conducted using the R-studio (RStudio, Boston, MA, USA) and STATA software (StataCorp LLC, College Station, TX, USA). The pooled in-hospital mortality rate was 7% (95% CI 0.05-0.09; I²=76%) and 12% for renal failure (95% CI 0.09-0.15; I²=88%), while the rates for paraplegia and cerebrovascular accidents were 3% (95% CI 0.02-0.04; I²=0%) and 6% (95% CI 0.05-0.08; I²=73%), respectively. Lower heterogeneity was attained after the stratification by the aortic pathologies, except for the renal failure. The distal anastomosis of the stent in zone 2 was significantly correlated with a lower renal failure development compared to zone 3 (odds ratio 0.52; 95% CI 0.33-0.82; P=0.069; I²=0%).

CONCLUSIONS

Our results indicate that the morbidities and mortality following TAR with FET were acceptable. We also associated the distal anastomosis in zone 2 with fewer renal failure development compared to that in zone 3.

Preoperative Nomogram and Risk Calculator for Postoperative Hypoxemia and Related Clinical Outcomes Following Stanford Type A Acute Aortic Dissection Surgery

Background

Hypoxemia is a common complication after Stanford type A acute aortic dissection surgery (AADS), however, few studies about hypoxemia after AADS exist. The aims of this study were to identify independent risk factors for hypoxemia after AADS and to clarify its association with clinical outcomes.

Methods

Patients undergoing AADS from 2016 to 2019 in our hospital were identified and used as a training set. Preoperative variables were first screened by univariate analysis and then entered into a multivariate logistic regression analysis to identify independent risk factors. A nomogram and an online risk calculator were constructed based on the logistic model to facilitate clinical practice and was externally validated in an independent dataset.

Results

Severe hypoxemia developed in 119 of the 492 included patients (24.2%) and poorer clinical outcomes were observed in these patients. Five independent risk factors for severe hypoxemia after AADS were identified by multivariate analysis, including older age, smoking history, renal insufficiency, higher body mass index, and white blood cell count. The model showed good calibration, discrimination, and clinical utility in the training set, and was well validated in the validation set. Risk stratification was performed and three risk groups were defined as low, medium, and high risk groups. Hypertension was identified as an independent risk factor for moderate hypoxemia besides the five predictors mentioned above, and renal insufficiency was not significant for mild hypoxemia by multivariate analysis. In addition, although frozen elephant trunk was associated with increased risk of postoperative hypoxemia in the univariate analysis, frozen elephant trunk was also not identified as an independent risk factor for postoperative hypoxemia in the multivariate analysis.

Conclusion

Hypoxemia was frequent following AADS, related to poorer clinical outcomes. Predictors were identified and a nomogram as well as an online risk calculator predicting severe hypoxemia after AADS was developed and validated, which may be helpful for risk estimation and perioperative management.

Prediction model for postoperative severe acute lung injury in patients undergoing acute type A aortic dissection surgery

OBJECTIVE

This study aimed to establish a risk assessment model to predict postoperative severe acute lung injury (ALI) risk in patients with acute type A aortic dissection (ATAAD).

METHODS

Consecutive patients with ATAAD admitted to our hospital were included in this retrospective assessment and placed in the postoperative severe ALI and nonsevere ALI groups based on the presence or absence of ALI within 72 h postoperatively (oxygen index [OI] ≤ 100 mmHg). Patients were then randomly divided into training and validation groups in a ratio of 8:2. Univariate and multivariate stepwise forward logistic regression analyses were used to statistically assess data and establish the prediction model. The prediction model's effectiveness was evaluated via 10-fold cross-validation of the validation group to facilitate the construction of a nomogram.

RESULTS

After the screening, 479 patients were included in the study: 132 (27.6%) in the postoperative severe ALI group and 347 (72.4%) in the postoperative nonsevere ALI group. Based on multivariate logistics regression analyses, the following variables were included in the model: coronary heart disease, cardiopulmonary bypass (CPB) ≥ 257.5 min, left atrium diameter ≥ 35.5 mm, hemoglobin ≤ 139.5 g/L, preCPB OI ≤ 100 mmHg, intensive care unit OI ≤ 100 mmHg, left ventricular posterior wall thickness ≥ 10.5 mm, and neutrophilic granulocyte percentage ≥ 0.824. The area under the receiver operating characteristic (ROC) curve of the modeling group was 0.805 and differences between observed and predicted values were not deemed statistically significant via the Hosmer-Lemeshow test (χ²  = 6.037, df = 8, p = .643). For the validation group, the area under the ROC curve was 0.778, and observed and predicted value differences were insignificant when assessed using the Hosmer-Lemeshow test (χ²  = 3.3782, df = 7; p = .848). The average 10-fold cross-validation score was 0.756.

CONCLUSIONS

This study established a prediction model and developed a nomogram to determine the risk of postoperative severe ALI after ATAAD. Variables used in the model were easy to obtain clinically and the effectiveness of the model was good.

Nitric Oxide Inhalation Therapy Attenuates Postoperative Hypoxemia in Obese Patients with Acute Type A Aortic Dissection

Objective

To investigate the differences between inhaled nitric oxide (iNO) treatment and conventional therapy in the treatment of postoperative hypoxemia in obese patients with acute type A aortic dissection (ATAAD).

Methods

ATAAD patients diagnosed and treated with emergency surgery in our hospital from June 2017 to December 2019 were retrospectively analyzed. Patients with postoperative hypoxemia were divided into the iNO group and control group. Propensity score matching was used to analyze clinical characteristics and results of the two groups.

Results

A total of 218 ATAAD patients with BMI ≥ 25 were treated with surgery. Among them, 115 patients developed refractory hypoxemia (64 in the control group and 51 in the iNO group). Patients in the iNO group had significantly shorter invasive mechanical ventilation time, intensive care unit (ICU) stay, and hospital stay. After 6 h of iNO treatment, the PaO2/FiO2 ratio in the iNO group increased significantly, and this ratio was higher than that in the control group at 6, 12, 24, 48, and 72 h after treatment.

Conclusion

Low-dose iNO could improve oxygenation and shorten mechanical ventilation and ICU stay in patients with hypoxemia after ATAAD surgery, but without significant side effects or increase in postoperative mortality or morbidity. These findings provide a basis for a randomized multicenter controlled trial to assess the efficacy of iNO in the treatment of hypoxemia after ATAAD surgery.

Predictors of hypoxemia in type-B acute aortic syndrome: a retrospective study

Acute aortic syndrome (AAS) can be life-threatening owing to a variety of complications, and it is managed in the intensive care unit (ICU). Although Stanford type-B AAS may involve hypoxemia, its predictors are not yet clearly understood. We studied clinical factors and imaging parameters for predicting hypoxemia after the onset of type-B AAS. We retrospectively analyzed patients diagnosed with type-B AAS in our hospital between January 2012 and April 2020. We defined hypoxemia as PaO₂/FiO₂ ≤ 200 within 7 days after AAS onset and used logistic regression analysis to evaluate prognostic factors for hypoxemia. We analyzed 224 consecutive patients (140 males, mean age 70 ± 14 years) from a total cohort of 267 patients. Among these, 53 (23.7%) had hypoxemia. The hypoxemia group had longer ICU and hospital stays compared with the non-hypoxemia group (median 20 vs. 16 days, respectively; p = 0.039 and median 7 vs. 5 days, respectively; p < 0.001). Male sex (odds ratio [OR] 2.87; 95% confidence interval [CI] 1.24–6.63; p = 0.014), obesity (OR 2.36; 95% CI 1.13–4.97; p = 0.023), patent false lumen (OR 2.33; 95% CI 1.09–4.99; p = 0.029), and high D-dimer level (OR 1.01; 95% CI 1.00–1.02; p = 0.047) were independently associated with hypoxemia by multivariate logistic analysis. This study showed a significant difference in duration of ICU and hospital stays between patients with and without hypoxemia. Furthermore, male sex, obesity, patent false lumen, and high D-dimer level may be significantly associated with hypoxemia in patients with type-B AAS.

Correlation of coagulopathy and frozen elephant trunk use in aortic arch surgery: A systematic review and meta-analysis

BACKGROUND

The advent of frozen elephant trunk (FET) for reconstruction of elective and nonelective aortic arch surgery has augmented the treatment of complex aortic pathologies in a single-stage operation. To date, no studies have been focused on the prevalence and predictors of coagulopathy potentiated by FET procedure.

METHODS

In a systematic review, we searched databases up to June 2020 to find studies reporting coagulopathy complications after FET procedure. A proportional meta-analysis was carried out using STATA software (StataCorp).

RESULTS

A total of 46 studies consisting of 6313 patients were eligible. The pooled estimation of reoperation for postoperative bleeding was 7% (95% confidence interval [CI:] 5-8; I²  = 84.73%; reported by 39 studies including 4796 patients). The mean volume of transfused packed blood cells and fresh frozen plasma was 1677 ml (95% CI: 1066.4-2287.6) and 1016.5 ml (95% CI: 450.7-1582.3). The subgroup by the stent type showed a decrease in the heterogeneity (I²  = 0.01%, I²  = 53.95%, I²  = 0.01%, and I²  = 54.41% for Thoraflex® Hybrid, E-vita®, Frozenix®, and Cronus®, respectively). The subgroup by the chronicity of operation resulted in less heterogeneity among patients undergoing elective compared with nonelective operation (I²  = 29.22% vs. I²  = 80.56% in nonelective). Meta-regression analysis showed that age and male gender significantly impacted on the reoperation for postoperative bleeding.

CONCLUSIONS

The FET procedure for arch replacement is associated with coagulopathy complications and the transfusion of blood products. Male, age, and selective choice of FET use were found to be the heterogeneity sources of reoperation for postoperative bleeding.

The risk factors for postoperative acute respiratory distress syndrome in Stanford type a acute aortic dissection patients

OBJECTIVE

To explore the risk factors for postoperative acute respiratory distress syndrome (ARDS) in Stanford type A acute aortic dissection (AAD) patients.

METHODS

This study included 64 patients with Stanford type A AAD who underwent Sun's procedure. The patients were divided into an ARDS group (PaO₂/FiO₂ < 200 mmHg) and a non-ARDS group (PaO₂/FiO₂ ≥ 200 mmHg). We compared the patients' perioperative clinical features in the two groups. A multivariate binary logistic regression was used to analyze the risk factors for ARDS in the Stanford type A AAD patients.

RESULTS

The incidence of postoperative ARDS was 56.25%. There were 13 deaths in the 6-month follow-up, including 8 in the ARDS group and 5 in the non-ARDS group. There were differences in the body mass index (BMI) levels, the times from onset to operation, the preoperative white blood cell counts, the preoperative hemoglobin levels, the preoperative alanine aminotransferase levels, the preoperative blood creatinine levels, the preoperative PaO₂/FiO₂, intraoperative blood transfusion volumes, the assisted mechanical ventilation times, and the durations of the intensive care unit stays between the two groups (all P < 0.05). The logistic regression analysis revealed that a BMI ≥ 25 kg/m², a time from onset to operation ≥ 24 hours, a preoperative white blood cell count ≥ 10×10⁹/L, and a preoperative PaO₂/FiO₂ < 300 mmHg were the independent risk factors for postoperative ARDS in patients with Stanford type A AAD.

CONCLUSIONS

ARDS occurs often in Stanford type A AAD patients. A BMI ≥ 25 kg/m², a time from onset to operation ≥ 24 hours, a preoperative white blood cell count ≥ 10×10⁹/L, and a preoperative PaO₂/FiO₂ < 300 mmHg are the independent risk factors for postoperative ARDS in these patients.

Hypothermic circulatory arrest time affects neurological outcomes of frozen elephant trunk for acute type A aortic dissection: A systematic review and meta-analysis

BACKGROUND

The treatment of complex thoracic aorta pathologies remains a challenge for cardiovascular surgeons. After introducing Frozen Elephant Trunk (FET), a significant evolution of surgical techniques has been achieved. The present meta-analysis aimed to assess the efficacy of FET in acute type A aortic dissection (ATAAD) and the effect of circulatory arrest time on post-operative neurologic outcomes.

METHODS

A standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses search was conducted for all observational studies of patients diagnosed with ATAAD undergoing total arch replacement with FET reporting in-hospital mortality, bleeding, and neurological outcomes. A random-effect meta-analysis was performed using STATA software (StataCorp, TX, USA).

RESULTS

Thirty-five studies were eligible for the present meta-analysis, including 3211 patients with ATAAD who underwent total arch replacement with FET. The pooled estimate for in-hospital mortality, postoperative stroke, and spinal cord injury were 7% (95% CI 5 - 9; I²  = 68.65%), 5% (95% CI 4 - 7; I²  = 63.93%), and 3% (95% CI 2 - 4; I²  = 19.56%), respectively. Univariate meta-regression revealed that with increasing the duration of hypothermic circulatory arrest time, the effect sizes for postoperative stroke and SCI enhances.

CONCLUSIONS

It seems that employing the FET procedure for acute type A dissection is associated with acceptable neurologic outcomes and a similar mortality rate comparing with other aorta pathologies. Besides, increasing hypothermic circulation arrest time appears to be a significant predictor of adverse neurologic outcomes after FET.

Inhaled nitric oxide reduces the intrapulmonary shunt to ameliorate severe hypoxemia after acute type A aortic dissection surgery

BACKGROUND

To assess the relationship between the intrapulmonary shunt and PaO₂/FiO₂ in severe hypoxemic patients after acute type A aortic dissection (ATAAD) surgery and to evaluate the effect of inhaled nitric oxide (iNO) on intrapulmonary shunt.

METHODS

Postoperative ATAAD patients with PaO₂/FiO₂ ≤ 150 mmHg were enrolled. Intrapulmonary shunt was calculated from oxygen content of different sites (artery [CaO₂], mixed venous [CvO₂], and alveolar capillary [CcO₂]) using the Fick equation, where intrapulmonary shunt = (CcO₂-CaO₂)/(CcO₂-CvO₂). Related variables were measured at baseline (positive end expiratory pressure [PEEP] 5 cm H₂O), 30 min after increasing PEEP (PEEP 10 cm H₂O), 30 min after 5 ppm iNO therapy (PEEP 10 cm H₂O + iNO), and 30 min after decreasing PEEP (PEEP 5 cm H₂O + iNO).

RESULTS

A total of 20 patients were enrolled between April 2019 and December 2019. Intrapulmonary shunt and PaO₂/FiO₂ were correlated in severe hypoxemic, postoperative ATAAD patients (adjusted R² = 0.467, p < 0.001). A mixed model for repeated measures revealed that iNO, rather than increasing PEEP, significantly decreased the intrapulmonary shunt (by 15% at a PEEP of 5 cm H₂O and 16% at a PEEP of 10 cm H₂O, p < 0.001 each) and increased PaO₂/FiO₂ (by 63% at a PEEP of 5 cm H₂O and 65% at a PEEP of 10 cm H₂O, p < 0.001 each). After iNO therapy, the decrement of intrapulmonary shunt and the increment of PaO₂/FiO₂ were also correlated (adjusted R² = 0.375, p < 0.001).

CONCLUSIONS

This study showed that intrapulmonary shunt and PaO₂/FiO₂ were correlated in severe hypoxemic, postoperative ATAAD patients. Furthermore, iNO, rather than increasing PEEP, significantly decreased the intrapulmonary shunt to improve severe hypoxemic conditions.

Frozen elephant trunk in total arch replacement: A systematic review and meta-analysis of outcomes and aortic proximalization

BACKGROUND AND AIM OF THE STUDY

The frozen elephant trunk (FET) procedure became a popular entity for utilization in aortic arch aneurysm disease. However, its proper mortality and morbidities as well as the predictors of outcomes are poorly identified. This systematic review and meta-analysis explore FET outcomes and its predictors with a focus on zone aortic proximalization.

METHODS

We searched PubMed/MEDLINE, EMBASE, and Scopus databases from their beginning to June 2020 to find studies reporting the outcomes of the FET procedure for the total arch replacement (TAR).

RESULTS

A total of 64 studies including 7967 patients were evaluated. The pooled estimates of cerebrovascular accidents, paraplegia, renal failure, and in-hospital mortality were 7.104 (95% confidence interval [CI], 5.691-8.661; I²  = 78.53%), 3.465 (95% CI, 2.852-4.136; I²  = 15.96), 14.969 (95% CI, 11.361-18.977; I²  = 91.26%), and 8.933 (95% CI, 7.128-10.919; I²  = 78.51%), respectively. Stratification by the geographical locations and by the aortic pathologies led to lower heterogeneity, but not for renal failure. The distal anastomosis in Zone 2 was associated with a lower rate of renal failure compared with Zone 3 (odds ratio, 0.54; 95% CI, 0.36-0.81; p = .003; I²  = 0%).

CONCLUSIONS

The FET procedure for TAR can be performed with acceptable mortality and morbidities among patients with complex aortic pathologies. Moreover, the distal anastomosis in Zone 2 was associated with lower renal failure compared to Zone 3.

Effects of Obesity on Outcomes of Acute Type A Aortic Dissection Repair in Japan

Background: The prevalence of obesity among Japanese acute type A aortic dissection (ATAAD) patients and its effect on repair outcomes remain to be elucidated.

Methods and Results: The prevalence of obesity (body mass index [BMI] ≥30.0 kg/m²) among 1,059 patients (mean [±SD] age 64.3±12.7 years) who underwent ATAAD repair between 1990 and 2018 was compared with that among the general Japanese population (National Health and Nutrition Survey data). The prevalence of obesity among male patients (17.1% [6/35], 20.0% [18/90], and 14.4% [20/139] for those aged 20–39, 40–49, and 50–59 years, respectively) was significantly higher than that among the age- and sex-matched general population. The 1,059 patients were divided into groups according to weight (normal [BMI <25.0 kg/m²; n=742], overweight [BMI 25.0–29.9 kg/m²; n=248], or obese [BMI ≥30.0 kg/m²; n=69]). Comparing the normal weight, overweight, and obese groups revealed significant differences among the 3 groups in median cardiopulmonary bypass time (143, 167, and 183 min, respectively), ventilation >48 h (44.5%, 60.1%, and 78.3%, respectively), and in-hospital mortality (7.0%, 7.3%, and 17.4%, respectively), but not in 30-day survival. Shock, visceral malperfusion, operation time >360 min, obesity, and coronary malperfusion were identified as predictors of in-hospital mortality.

Conclusions: The prevalence of obesity is increased among Japanese male patients with ATAAD aged ≤59 years. Obesity may increase these patients’ operative risk; overweight does not.