Cardioprotective effects of acute isovolemic hemodilution in a rat model of transient coronary occlusion*

Myocardial injury is a risk factor for 6-week mortality in liver cirrhosis associated esophagogastric variceal bleeding

This study sought to investigate risk factors for 6-week mortality of patients with decompensated liver cirrhosis associated esophagogastric variceal bleeding (EGVB) and clinical characteristics of myocardial injury in cirrhotic patients with EGVB. This retrospective cohort study included 249 patients with decompensated liver cirrhosis associated EGVB in the Department of Emergency. Patients were divided into two groups including liver cirrhosis associated EGVB without myocardial injury and liver cirrhosis associated EGVB with myocardial injury. Myocardial injury, recurrent bleeding, total bilirubin (TBIL) level and dyslipidemia are independent risk factors for 6-week mortality in liver cirrhosis associated EGVB. Among all patients with liver cirrhosis associated EGVB, 90 (36.2%) had myocardial injury and 159 individuals (63.8%) not. The 6-week mortality in the group with myocardial injury was 21%, which was significantly higher than that of 7% in the group without myocardial injury. More patients in the myocardial injury group smoked, had moderate to severe esophageal varices, liver failure, and Child-Pugh C liver function compared to the non-myocardial injury group. Myocardial injury, recurrent bleeding, TBIL level and dyslipidemia are independent risk factors for death within 6 weeks in liver cirrhosis associated EGVB. The 6-week mortality is considerably higher in patients with myocardial injury in liver cirrhosis associated EGVB than those without myocardial injury.

Risk factors, prediction model, and prognosis analysis of myocardial injury after acute upper gastrointestinal bleeding

Background

Cardiovascular complications in patients with acute upper gastrointestinal bleeding (AUGIB) have been associated with a high-risk of subsequent adverse consequences. This study aimed to analyze the risk factors for myocardial injury in AUGIB patients, predict the risk of myocardial injury, and explore the clinical prognosis and influencing factors in AUGIB patients with myocardial injury.

Materials and methods

A retrospective case-control study based on AUGIB patients in the First Affiliated Hospital of Xi'an Jiaotong University from 2016 to 2020 was performed. We divided the enrolled patients into a myocardial injury group and a control group according to whether they developed myocardial injury. The variables significant in the univariate analysis were subjected to binary logistic regression for risk factor analysis and were used to establish a nomogram for predicting myocardial injury. In addition, logistic regression analysis was performed to better understand the risk factors for in-hospital mortality after myocardial injury.

Result

Of the 989 AUGIB patients enrolled, 10.2% (101/989) developed myocardial injury. Logistic regression analysis showed that the strong predictors of myocardial injury were a history of hypertension (OR: 4.252, 95% CI: 1.149-15.730, P = 0.030), blood urea nitrogen (BUN) (OR: 1.159, 95% CI: 1.026-1.309, P = 0.018) and left ventricular ejection fraction (LVEF) <68% (OR: 3.667, 95% CI: 1.085-12.398, P = 0.037). The patients with a tumor history (digestive system tumors and non-digestive system tumors) had no significant difference between the myocardial injury group and the control group (P = 0.246). A prognostic nomogram model was established based on these factors with an area under the receiver operator characteristic curve of 0.823 (95% CI: 0.730-0.916). The patients with myocardial injury had a much higher in-hospital mortality rate (10.9% vs. 2.0%, P < 0.001), and an elevated D-dimer level was related to in-hospital mortality among the AUGIB patients with myocardial injury (OR: 1.273, 95% CI: 1.085-1.494, P = 0.003).

Conclusion

A history of hypertension, renal dysfunction, and cardiac function with LVEF <68% were strong predictors of myocardial injury. Coagulopathy was found to be associated with poor prognosis in AUGIB patients with myocardial injury.

Relation of Preprocedural Hemoglobin Level to Outcomes After Percutaneous Coronary Intervention

Adverse effects have been reported in patients with preprocedural anemia after percutaneous coronary intervention (PCI), but data regarding the relation between elevated hemoglobin (Hb) level and post-PCI prognosis remain limited. This study assessed the impact of elevated Hb on major adverse cardiac and cerebrovascular event (MACCE) at 12 months, a composite of all-cause mortality, nonfatal myocardial infarction, and ischemic stroke after PCI. We pooled patient-level data from four Korean multicenter drug-eluting stent registries from 2010 to 2016. In total, 5,107 patients were divided into 5 categories according to the baseline Hb level (<10, 10 to 12.9, 13 to 14.9, 15 to 16.9 and ≥17 g/dl). Patients with higher Hb levels were significantly younger, predominantly male, current smokers with higher body mass index, and more frequent dyslipidemia. Hypertension, diabetes, chronic kidney disease, and cerebrovascular accident were more prevalent in lower Hb groups. Categorically, a U-shaped curvilinear relation was observed between baseline Hb and clinical outcomes showing significantly higher MACCE rate in <10g/dl (hazard ratio [HR], 4.62 [2.81 to 7.68]) and ≥17 g/dl (HR, 4.06 [1.57 to 10.5]) groups compared with the reference group (13 to 14.9 g/dl), especially in men. In nonanemic patients (Hb ≥13 g/dl), adjusted HRs of MACCE, mortality, and stroke were significantly higher in ≥17 g/dl group than in the reference group. Furthermore, ≥17 g/dl was an independent predictor for MACCE and all-cause mortality after PCI. In conclusion, not only low Hb but also elevated Hb of ≥17 g/dl was significantly associated with higher MACCE rates and all-cause mortality after PCI. An appropriate treatment strategy for patients with high Hb level should be identified through future studies.

A feasibility and safety study of intracoronary hemodilution during primary coronary angioplasty in order to reduce reperfusion injury in myocardial infarction

OBJECTIVES

We designed a pilot study to evaluate safety and feasibility of an inexpensive and simple approach to intracoronary hemodilution during primary angioplasty (PPCI) to reduce reperfusion injury.

INTRODUCTION

Early revascularization in acute myocardial infarction decreases infarct size and improves outcomes. However, abrupt restoration of coronary flow results in myocardial reperfusion injury and increased final infarct size. Dilution of coronary blood during revascularization may help reduce this damage. If proved effective, such an approach would need to be simple and suitable for widespread adoption.

METHODS

Ten patients presenting with STEMI underwent intracoronary dilution with room temperature Hartmann's solution delivered through the guiding catheter during primary angioplasty (PPCI). Infusion of perfusate began prior to crossing the occluded artery with the guidewire, continuing until 10 min after completion of the balloon and stenting procedure. Infusion was briefly interrupted for contrast injection and pressure monitoring. The outcome measures were safety, including intracoronary temperature reduction and volume of intracoronary perfusate infused, and technical feasibility.

RESULTS

There were no significant symptomatic, hemodynamic, ECG ST/T segment or rhythm changes observed during perfusate administration. The median (interquartile range) volume of perfusate administered was 550 mL (350-725 mL) and the median intracoronary temperature reduction observed was 3.4°Celsius. Myocardial salvage was 0.54 (0.43-0.65).

CONCLUSIONS

Transcatheter intracoronary hemodilution with room temperature perfusate during PPCI is feasible and appears safe. Such a strategy is simple and inexpensive, with potential to be widely applied. Further mechanistic and subsequent outcome powered studies are required to evaluate whether this strategy can reduce reperfusion injury in STEMI.

Impact of blood transfusion on short- and long-term mortality in patients with ST-segment elevation myocardial infarction

OBJECTIVES

We sought to examine the short- and long-term outcomes of blood transfusion in patients presenting with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

The short- and long-term consequences of blood transfusion in anemic patients with recent STEMI remain controversial.

METHODS

We evaluated 30-day, 6-month, and 1-year all-cause mortality among 4,131 STEMI patients enrolled in the GUSTO (Global Use of Strategies to Open Occluded Coronary Arteries) IIb trial. Patients were categorized according to whether they received a blood transfusion during hospitalization. Cox proportional hazards survival models with transfusion as a time-dependent covariate were conducted for the whole and for the propensity-matched groups. Additionally, a series of sensitivity analyses assessed the magnitude of hidden bias that would need to be present to explain the associations actually observed.

RESULTS

Death at 30 days (13.7% vs. 5.5%), 6 months (19.7% vs. 6.9%), and 1 year (21.8% vs. 8.7%) was significantly higher for transfused patients than for nontransfused patients, respectively. After adjusting for over 25 baseline characteristics, nadir hemoglobin, and propensity score for transfusion, and using transfusion as a time-dependent covariate, transfusion remained significantly associated with increased risk of mortality at 30 days (hazard ratio [HR]: 3.89, 95% confidence interval [CI]: 2.66 to 5.68, p < 0.001), 6 months (HR: 3.63, 95% CI: 2.67 to 4.95, p < 0.001), and 1 year (HR: 3.03, 95% CI: 2.25 to 4.08, p < 0.001). Similar results were observed in the propensity-matched patients.

CONCLUSIONS

Blood transfusion is associated with increased short- and long-term mortality in the setting of STEMI.

The effects of hemodilution on acute inflammatory responses in a bleomycin-induced lung injury model

Acute normovolemic hemodilution (ANH) can be used in acute lung injury (ALI) patients who refuse blood transfusions. To investigate the effects of hemodilution on the acute inflammatory response in lung injury, the authors studied the effects of ANH in a rat model of bleomycin-induced lung injury. Bleomycin (10 mg/kg) was used to induce lung injury in 2 groups of rats. The treatment groups included a lung injury group with hemodilution (HI), a lung injury group without hemodilution (NHI), and a control group. Hemodilution was performed by removing blood and substituting the same amount of hydroxyethyl starch solution targeted to 7.0 g/dL via the right and left internal jugular veins. At day 3 after bleomycin instillation, systemic hemoglobin concentration was 9.5 +/- 1.1 g/dL. Tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 levels measured in the bronchoalveolar lavage fluid (BALF), blood, and lung tissue were not significantly different between the HI and NHI groups 3 days after lung injury. Microscopic findings showed fibrosis and inflammation in the HI and NHI groups 28 days after lung injury, but no significant differences were found between the 2 groups. Hemodilution after bleomycin administration did not further affect the acute inflammatory response or lung injury.

Red blood cell transfusion in the treatment and management of anaemia: the search for the elusive transfusion trigger

Therapeutic red blood cell (RBC) transfusion is widely utilized in the management of anaemia. Critically ill intensive care unit (ICU) patients in particular, as well as medical and haematology-oncology patients, are among the largest groups of users of RBC products. While anaemia is common in these patients, its treatment and management, including appropriate thresholds for RBC transfusion, remain controversial. We review here the function of RBCs in oxygen transport and physiology, with a view to their role in supporting and maintaining systemic tissue oxygenation. Adaptive and physiological compensatory mechanisms in the setting of anaemia are discussed, along with the limits of compensation. Finally, data from clinical studies will be examined in search of evidence for, or against, a clinically relevant transfusion trigger.

Acute normovolaemic haemodilution with a novel hydroxyethyl starch (130/0.4) reduces focal cerebral ischaemic injury in rats

BACKGROUND AND OBJECTIVES

This study investigated the neuroprotective effect of acute normovolaemic haemodilution with a novel hydroxyethyl starch (130/0.4, HES) on focal cerebral ischaemia-reperfusion injury and determined optimum degree for haemodilution in the rat.

METHODS

Male Sprague-Dawley rats were randomly divided into three groups (n = 10 each): hydroxyethyl starch, saline and controls. Animals in the hydroxyethyl starch and saline groups were haemodiluted until haematocrit decreased to 30% of baseline. In another experiment male Sprague-Dawley rats were randomly assigned to four groups (n = 10 each): HES30, HES25 and HES20 and controls. Rats in the HES30, HES25 and HES20 groups were haemodiluted with hydroxyethyl starch until the haematocrit decreased to 30%, 25% and 20%, respectively. At 15 min after haemodilution, all the rats were subjected to a right middle cerebral artery occlusion for 120 min. Neurologic deficit scores and infarct volumes were assessed 24 h after reperfusion.

RESULTS

Haemodilution with hydroxyethyl starch improved neurologic outcome (P < 0.01) and reduced infarct volume (P < 0.01) compared to saline and controls. Haemodilution with saline augmented infarct volume (P < 0.05 vs. controls). Neurologic deficit scores in HES30 and HES25 groups were significantly lower compared to controls (P < 0.05) while infarct volumes in controls and HES20 were significantly larger compared to HES30 and HES25 (P < 0.01).

CONCLUSIONS

This study demonstrates that acute normovolaemic haemodilution with a novel hydroxyethyl starch (130/0.4) reduces infarct volume and improves neurological outcome after focal cerebral ischaemia in a rat stroke model. Neuroprotection by haemodilution was highest at haematocrit dilution between 25% and 30%, while ischaemic injury was exacerbates when haematocrit was diluted to 20%.

[Tolerance to perioperative anemia. Mechanisms, influencing factors and limits]

The expected cost explosion in transfusion medicine increases the socio-economic significance of specific institutional transfusion programs. In this context the estimated use of the patient's physiologic tolerance represents an integral part of any blood conservation concept. The present article summarizes the mechanisms, influencing factors and limits of this natural tolerance to anemia and deduces the indication for perioperative red blood cell transfusion. The current recommendations coincide to the effect that perioperative transfusion is unnecessary up to a Hb concentration of 10 g/dl (6.21 mmol/l) even in older patients with cardiopulmonary comorbidity and is only recommended in cases of Hb <6 g/dl (<3.72 mmol/l) in otherwise healthy subjects including pregnant women and children. Critically ill patients with multiple trauma and sepsis do not seem to benefit from transfusions up to Hb concentrations >9 g/dl (>5.59 mmol/l). In cases of massive hemorrhaging and diffuse bleeding disorders the maintenance of a Hb concentration of 10 g/dl (6.21 mmol/l) seems to contribute to stabilization of coagulation.

Cardioprotective effects of acute normovolemic hemodilution in patients with severe aortic stenosis undergoing valve replacement

BACKGROUND

After acute normovolemic hemodilution (ANH), improvement of the rheologic conditions may contribute to optimize tissue oxygen delivery and attenuate ischemia-reperfusion injuries. It was hypothesized that ANH would confer additional cardioprotection in patients with ventricular hypertrophy undergoing open heart surgery.

STUDY DESIGN AND METHODS

This study was a randomized controlled trial. Forty patients scheduled for elective aortic valve replacement were randomly assigned to a control group (standard care) or an ANH group (target hematocrit level of 28%). All patients were managed with standard myocardial preservation techniques (cold blood cardioplegia, anesthetic preconditioning). The outcome measures included the release of myocardial enzymes, perioperative hemodynamic changes, the need for pharmacologic cardiovascular support, and cardiac complications.

RESULTS

In the ANH group, the postoperative release of troponin I (mean peak plasma concentrations, 1.7 ng/mL; 95% confidence interval, 1.4-2.1 ng/mL) and myocardial fraction of creatine kinase (22 U/L; range, 18-24 U/L) was significantly lower than in the control group (3.6 [range, 3.0-4.2] ng/mL and 45 [range, 39-51] U/L, respectively). In addition, requirement for inotropic support was significantly lower and fewer hemodiluted patients presented adverse cardiac events. After ANH, there was a significant decrease in heart rate (-11 +/- 6%) and rate-pressure product (-16 +/- 8%) until the aortic cross-clamping time and, at the end of surgery, the circulating levels of erythropoietin (EPO) were higher than in control patients (13.6 +/- 4.2 mUI/mL vs. 7.3 +/- 2.4 mUI/mL; p < 0.05).

CONCLUSIONS

Besides conventional cardiac preservation techniques, preoperative ANH further attenuates myocardial injuries. Optimization of preischemic myocardial oxygen delivery and/or consumption and the postconditioning effects of endogenous EPO are potential mechanisms for ANH-induced cardioprotection.

Indications for Blood Transfusion in Cardiac Surgery

In addition to its life-saving effect in hemorrhagic shock, transfusion of allogenic packed red blood cells can be beneficial in situations where a critically low hematocrit is contributing to a state of oxygen-supply dependency. These benefits are countered by the risks of transfusion-associated lung injury, transfusion-associated immunomodulation, and cellular hypoxia after RBC transfusion. The critical hematocrit is patient and organ specific, and varies intraoperatively according to the duration and temperature of bypass, as well as for a variable postoperative period. Future randomized studies must prospectively evaluate regional indicators of tissue oxygenation in transfusion algorithms.

[Tolerance to perioperative anemia. Mechanisms, influencing factors and limits]

The expected cost explosion in transfusion medicine (increasing imbalance between donors and potential recipients, treatment of transfusion-associated complications) increases the socio-economic significance of specific institutional transfusion programs. In this context the estimated use of the patient's physiologic tolerance to anemia enables 1) the tolerance of larger blood losses (loss of "diluted blood"), 2) the onset of transfusion to the time after surgical control of bleeding to be delayed and 3) the perioperative collection of autologous red blood cells. The present review article summarizes the mechanisms, influencing factors and limits of this natural tolerance to anemia and deduces the indication for perioperative red blood cell transfusion. Under strictly controlled conditions (anesthesia, normovolemia, complete muscular relaxation, hyperoxemia, mild hypothermia) extremely low hemoglobin concentrations [Hb <3 g/dl (<1.86 mmol/l)] are tolerated without transfusion by individuals with no cardiopulmonary disease. In the clinical routine these situations are limited to borderline situations e.g. unexpected massive blood losses in Jehovah's Witnesses or unexpected shortcomings in blood supply. The current recommendations coincide to the effect that perioperative red blood cell transfusion 1) is unnecessary up to a Hb concentration of 10 g/dl (6.21 mmol/l) even in older patients with cardiopulmonary comorbidity and 2) is only recommended in cases of Hb <6 g/dl (<3.72 mmol/l) in otherwise healthy subjects including pregnant women and children. Critically ill patients with multiple trauma and sepsis do not seem to benefit from transfusions up to Hb concentrations >9 g/dl (>5.59 mmol/l). In cases of massive hemorrhaging and diffuse bleeding disorders the maintenance of a Hb concentration of 10 g/dl (6.21 mmol/l) seems to contribute to stabilization of coagulation.

Anemia and perioperative red blood cell transfusion: a matter of tolerance

In the past, anemia in the perioperative period has been treated by red blood cell (RBC) transfusions relatively uncritically. RBC transfusions were believed to increase oxygen delivery by increasing hemoglobin concentration. Arbitrary transfusion triggers such as the "10/30 rule" (i.e., RBC transfusion indicated below a hemoglobin concentration of 10 g/dL or a hematocrit of 30%) were applied. However, there is now increasing evidence that RBC transfusions are associated with adverse outcomes and should be avoided whenever possible. Restraining from RBC transfusions and maintaining normovolemia in patients suffering from surgical blood loss results in acute anemia. Therefore, knowing the compensatory mechanisms during acute anemia is crucial. This review focuses on acute anemia tolerance, its limits, and physiologic transfusion triggers in the perioperative period.