Importance of blood pressure regulation in maintaining adequate tissue perfusion during cardiopulmonary bypass

Postoperative stroke in acute type A aortic dissection: incidence, outcomes, and perioperative risk factors

BACKGROUND

Despite advances in surgical techniques, the incidence of stroke following acute type A aortic dissection (ATAAD) repair remains markedly high, with substantial immediate and long-term adverse outcomes such as elevated mortality, extended hospital stays, and persistent neurological impairments. The complexity of managing ATAAD extends beyond the operation itself, highlighting a crucial gap in research concerning modifiable preoperative patient conditions and perioperative anesthetic management strategies.

OBJECTIVES

This investigation aimed to elucidate the incidence, consequences, and perioperative determinants of stroke following surgical intervention for acute type A aortic dissection (ATAAD).

METHODS

In a multicenter retrospective analysis, 516 ATAAD surgery patients were evaluated. The data included demographic information, clinical profiles, surgical modalities, and outcomes. The primary endpoint was postoperative stroke incidence, with hospital mortality and other complications serving as secondary endpoints.

RESULTS

Postoperative stroke occurred in 13.6% of patients (70 out of 516) and was associated with significant extension of the ICU (median 10 vs. 5 days, P < 0.001) and hospital stay (median 18 vs. 12 days, P < 0.001). The following key independent stroke risk factors were identified: modified Frailty Index (mFI) ≥ 4 (odds ratio [OR]: 4.18, 95% confidence interval [CI]: 1.24-14.1, P = 0.021), common carotid artery malperfusion (OR: 3.76, 95% CI: 1.23-11.44, P = 0.02), pre-cardiopulmonary bypass (CPB) hypotension (mean arterial pressure ≤ 50 mmHg; OR: 2.17, 95% CI: 1.06-4.44, P = 0.035), ≥ 20% intraoperative decrease in cerebral regional oxygen saturation (rSO2) (OR: 1.93, 95% CI: 1.02-3.64, P = 0.042), and post-CPB vasoactive-inotropic score (VIS) ≥ 10 (OR: 2.24, 95% CI: 1.21-4.14, P = 0.01).

CONCLUSIONS

Postoperative stroke significantly increases ICU and hospital durations in ATAAD surgery patients. These findings highlight the critical need to identify and mitigate major risks, such as high mFI, common carotid artery malperfusion, pre-CPB hypotension, significant cerebral rSO2 reductions, and elevated post-CPB VIS, to improve outcomes and reduce stroke prevalence.

TRIAL REGISTRATION

Thai Clinical Trials Registry (TCTR20230615002). Date registered on June 15, 2023. Retrospectively registered.

Effect of near-infrared spectroscopy on postoperative delirium in cardiac surgery with cardiopulmonary bypass: a systematic review and meta-analysis

Background

Postoperative delirium (POD) is a common anesthetic side effect in cardiac surgery. However, the role of oxygen saturation monitoring in reducing postoperative delirium has been controversial. Therefore, this meta-analysis aimed to analyze whether NIRS monitoring during cardiac surgery under cardiopulmonary bypass could reduce the incidence of postoperative delirium.

Methods

PubMed, Web of Science, Cochrane Library, Embase and China National Knowledge Infrastructure (CNKI) databases were systematically searched using the related keywords for randomized-controlled trials (RCTs) published from their inception to March 16, 2024. This review was conducted by the Preferred Reporting Project and Meta-Analysis Statement (PRISMA) guidelines for systematic review. The primary outcome was postoperative delirium, and the second outcomes included the length of ICU stay, the incidence of kidney-related adverse outcomes, and the incidence of cardiac-related adverse outcomes.

Results

The incidence of postoperative delirium could be reduced under the guidance of near-infrared spectroscopy monitoring (OR, 0.657; 95% CI, 0.447-0.965; P = 0.032; I2 = 0%). However, there were no significant differences in the length of ICU stay (SMD, 0.005 days; 95% CI, -0.135-0.146; P = 0.940; I2 = 39.3%), the incidence of kidney-related adverse outcomes (OR, 0.761; 95% CI, 0.386-1.500; P = 0.430; I2 = 0%), and the incidence of the cardiac-related adverse outcomes (OR, 1.165; 95% CI, 0.556-2.442; P = 0.686; I2 = 0%) between the two groups.

Conclusion

Near-infrared spectroscopy monitoring in cardiac surgery with cardiopulmonary bypass helps reduce postoperative delirium in patients.

Systematic Review Registration

PROSPERO, identifier, CRD42023482675.

Endothelial Function and Hypoxic–Hyperoxic Preconditioning in Coronary Surgery with a Cardiopulmonary Bypass: Randomized Clinical Trial

A hypoxic–hyperoxic preconditioning (HHP) may be associated with cardioprotection by reducing endothelial damage and a beneficial effect on postoperative outcome in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Patients (n = 120) were randomly assigned to an HHP and a control group. A safe, inhaled oxygen fraction for the hypoxic preconditioning phase (10–14% oxygen for 10 min) was determined by measuring the anaerobic threshold. At the hyperoxic phase, a 75–80% oxygen fraction was used for 30 min. The cumulative frequency of postoperative complications was 14 (23.3%) in the HHP vs. 23 (41.1%), p = 0.041. The nitrate decreased after surgery by up to 20% in the HHP group and up to 38% in the control group. Endothelin-1 and nitric oxide metabolites were stable in HHP but remained low for more than 24 h in the control group. The endothelial damage markers appeared to be predictors of postoperative complications. The HHP with individual parameters based on the anaerobic threshold is a safe procedure, and it can reduce the frequency of postoperative complications. The endothelial damage markers appeared to be predictors of postoperative complications.

Lactate level during cardiopulmonary bypass as a predictor of postoperative outcomes in adult patients undergoing cardiac surgery

Background

It has been reported that prolonged intensive care unit (ICU) stay after cardiac surgery is associated with poor patient outcome. In addition, prolonged stay can block the efficient use of ICU beds with an increase in expenditure of health-care costs. The aim of the present study was to retrospectively determine which pre- and intra-operative factors could significantly affect ICU-free survival days (IFSD) which has been suggested to reflect postoperative patients’ outcome, as well as variables significantly associated with the main predictors of IFSD.

Findings

We reviewed anesthesia charts and medical records of 145 patients undergoing cardiac surgery under cardiopulmonary bypass (CPB) in our hospital from January 2014 to October 2015, and 72 patients’ records were finally used for the analysis. IFSD was a median of 25 days (95% CI 24–26). The multiple regression analysis indicated that preoperative estimated glomerular filtration rate, differences between preoperative mean arterial pressure and mean CPB pressure, and blood lactate level at 2 h after CPB (CPB-2 h) were independently associated with IFSD (β regression coefficients 0.086, −0.083, and −3.601, respectively).

Conclusion

In addition to preoperative renal function and differences between preoperative MAP and CPB pressure, the lactate level at CPB-2 h could be a major predictor of postoperative outcome in patients undergoing cardiac surgery.

Gastrointestinal complications following cardiac surgery with cardiopulmonary bypass

Gastrointestinal complications following cardiac surgery with cardiopulmonary bypass include paralytic ileus, stress ulcer, acute ischemic colitis, gastrointestinal bleeding, acute cholecystitis, acute pancreatitis, acute hepatic failure and so on. Due to the lack of diagnostic tests with high specificity and sensitivity, the early diagnosis of these complications is difficult, which leads to a higher mortality rate. Therefore, accurately identifying the risk factors is important for early diagnosis and treatment. The purpose of this paper is to review the pathogenesis, risk factors, diagnosis and treatment of gastrointestinal complications after cardiac surgery with cardiopulmonary bypass.

Recent Advances in Application of Cerebral Oximetry in Adult Cardiovascular Surgery

Cerebral oximetry is a noninvasive technology that continuously monitors cerebral tissue oxygen saturation, which is a sensitive index of global cerebral hypoperfusion. On the basis of near-infrared spectroscopy technology, information is provided on the availability of oxygen in brain tissue at risk during numerous pathological conditions. Complementary to the arterial oxygen saturation measured by pulse oximetry, cerebral tissue oxygen saturation reflects regional cerebral metabolism and the balance of local cerebral oxygen supply/demand. Recently, patient management with the guidance of cerebral oximetry has resulted in improved patient outcomes. This review will briefly describe the physics behind cerebral oximetry and will provide an overview of the literature focusing primarily on articles published within the past 5 years.

Moderate hypothermia induces a preferential increase in pancreatic islet blood flow in anesthetized rats

The aim of the study was to characterize the effects of induced moderate hypothermia on splanchnic blood flow, with particular reference to that of the pancreas and the islets of Langerhans. We also investigated how interference with the autonomic nervous system at different levels influenced the blood perfusion during hypothermia. For this purpose, hypothermia (body temperature of 28°C) was induced by external cooling, whereas normothermic (37.5°C) anesthetized Sprague-Dawley rats were used as controls. Some rats were pretreated with either propranolol, yohimbine, atropine, hexamethonium, or a bilateral abdominal vagotomy. Our findings suggest that moderate hypothermia elicits complex, organ-specific circulatory changes, with increased perfusion noted in the pylorus, as well as the whole pancreas and the pancreatic islets. The pancreatic islets maintain their high blood perfusion through mechanisms involving both sympathetic and parasympathetic mediators, whereas the increased pyloric blood flow is mediated through parasympathetic mechanisms. Renal blood flow was decreased, and this can be prevented by ganglionic blockade and is also influenced by β-adrenoceptors.

Pexelizumab reduces death and myocardial infarction in higher risk cardiac surgical patients

BACKGROUND

Morbidity and mortality after coronary artery bypass graft surgery are directly related to specific preoperative risk factors. We assessed the influence of preoperative risk factors on the effect of pexelizumab, a C5 complement inhibitor, to reduce postoperative morbidity and mortality in this post hoc analysis of the Pexelizumab for Reduction in Myocardial Infarction and MOrtality in Coronary Artery Bypass Graft surgery (PRIMO-CABG) trial, a phase III double-blind, placebo-controlled study of 3,099 patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass.

METHODS

The composite endpoint of death or myocardial infarction or both through postoperative day 30 was examined in subpopulations of patients with pre-specified risk factors, which included diabetes mellitus, prior coronary artery bypass graft, urgent intervention, female sex, history of neurologic event, history of congestive heart failure, and two or more previous myocardial infarctions or a recent myocardial infarction. Stratified post hoc analyses were also performed on patients presenting with two or more and three or more of those risk factors.

RESULTS

Pexelizumab significantly reduced the incidence of the composite endpoint of death or myocardial infarction through postoperative day 30 by 28% in patients with two or more risk factors (p = 0.004) and 44% in patients with three or more risk factors (p < 0.001).

CONCLUSIONS

The C5 complement inhibitor, pexelizumab, reduced morbidity and mortality among high-risk patients undergoing coronary artery bypass grafting with cardiopulmonary bypass.

Construction of a pulmonary artery pump for unifocalization and repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals

Single-stage repair has been presented as the treatment of choice for pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals. This surgical approach may result in the difficult decision of whether to close the ventricular septal defect. This decision may significantly affect the postoperative course of the patient. There are several diagnostic techniques clinicians may use to help them decide if closure is indicated. One technique is to modify an extracorporeal circuit to deliver precise flow rates of blood into the newly created pulmonary arterial system, at the same time supporting the patient during the operative procedure. While this technique is not novel, there is only a single published description of the circuit. This report is brief and does not discuss potential complications that these modifications may cause. Therefore, it is the purpose of this paper to describe a circuit modification to perform this diagnostic measurement as well as elucidating potential risks of this technique.

Selective Use of Off-Pump Coronary Bypass Surgery Reduces Mortality and Neurologic Morbidity Associated with High-Risk Coronary Bypass Surgery: A 400-Case Comparative Experience

The frequency of use of off-pump coronary artery bypass (CAB) surgery to surgically treat coronary artery disease has varied greatly from center to center and from surgeon to surgeon because of preference, training, and experience. We report an experience with 400 consecutive isolated CAB procedures selectively managed with on-pump or off-pump surgery, according to the perceived potential for aortic embolization or stroke as determined by clinical and imaging determinations. The off-pump CAB group (46 patients) was 7.1 years older (P < .05) and had an 11% lower ejection fraction (P < .03) than the on-pump group. There was no difference in gender, urgency of surgery, hemodynamic stability, angina class, or incidence of prior myocardial infarction. All 400 patients underwent intraoperative transesophageal echocardiography, and many underwent an epiaortic study to supplement image quality. Patients without palpable or imaged advanced aortic disease or deemed to be at clinically high risk for stroke (advanced age, prior strokes, or advanced cerebrovascular or peripheral vascular disease) underwent on-pump procedures requiring 55 minutes of aortic ischemia and 97 minutes of high-flow, high-pressure bypass on average. All others underwent off-pump procedures. The numbers of grafts per patient were similar (3.2 on-pump, 2.8 off-pump; = ns). There was no in-hospital or 30-day mortality in either group. Using the New York State risk-adjustment algorithm, we found the predicted mortality rate for the off-pump group was higher (2.24% on-pump versus 5.54% off-pump, P = .008). The postoperative length of stay was longer in the off-bypass group (3.67 days versus 4.31 days, P = .003). The frequencies of hospital readmission and perioperative complications (renal, pulmonary, infection, bleeding, cardiac, neurologic) were similar, and there were no postoperative strokes in either group. The selective use of off-pump surgery safely managed patients at higher risk for perioperative stroke and associated embolic multisystem organ failure and death. Individual surgeon and center-wide use of a selective approach is recommended as an alternative to a single-procedure nonselective approaches.

Improving Outcomes in Coronary Surgery: The Impact of Echo-Directed Aortic Cannulation and Perioperative Hemodynamic Management in 500 Patients

BACKGROUND

Stroke and death continue to occur perioperatively associated with on-pump and off-pump coronary artery bypass grafting surgery (CABG) procedures. We report on a prospectively implemented multifaceted strategy to improve short-term outcomes associated with on-pump CABG.

METHODS

Five hundred consecutive patients from a single teaching institution undergoing standardized on-pump nonreoperative CABG between June 1996 and July 2003 were entered into the New York State Cardiac Surgery database, a verified comprehensive clinical registry. Risk factors and outcomes were analyzed and compared with the statewide New York State CABG registry. All patients underwent intraoperative transesophageal echocardiography to guide distal aortic cannulation and high flow-high pressure cardiopulmonary bypass perfusion, arterial filtration, centrifugal pump perfusion, and membrane oxygenation. Intraoperative and early postoperative blood pressures were continuously targeted to match the patient's preoperative range.

RESULTS

The mean patient age was 63.5 years, 335 (67%) were male, and 320 (64%) were deemed to be of elective surgical priority. The mean ejection fraction was 0.434, with 255 (51%) having sustained a prior myocardial infarction. The mean cardiopulmonary bypass time was 95 minutes with an ischemic time of 51 minutes to accomplish a mean of 3.19 grafts/patient. The predicted group mortality was 2.28%, which was greater than the simultaneously measured 1.98% New York statewide CABG mortality during the same period for comparable patients (p < 0.05). There was no in-hospital or 30-day mortality nor were there any perioperative strokes in this group (p < 0.05). The mean postoperative hospital length of stay was 3.61 days with a 5.1% 30-day readmission rate.

CONCLUSIONS

A standardized approach to CABG using echocardiographic guided aortic cannulation and perioperative hemodynamic management reduces perioperative stroke and death associated with on-pump coronary surgery.