Bleeding in cardiac surgery: The use of aprotinin does not affect survival

Aprotinin-Drug against Respiratory Diseases

Aprotinin (APR) was discovered in 1930. APR is an effective pan-protease inhibitor, a typical "magic shotgun". Until 2007, APR was widely used as an antithrombotic and anti-inflammatory drug in cardiac and noncardiac surgeries for reduction of bleeding and thus limiting the need for blood transfusion. The ability of APR to inhibit proteolytic activation of some viruses leads to its use as an antiviral drug for the prevention and treatment of acute respiratory virus infections. However, due to incompetent interpretation of several clinical trials followed by incredible controversy in the literature, the usage of APR was nearly stopped for a decade worldwide. In 2015-2020, after re-analysis of these clinical trials' data the restrictions in APR usage were lifted worldwide. This review discusses antiviral mechanisms of APR action and summarizes current knowledge and prospective regarding the use of APR treatment for diseases caused by RNA-containing viruses, including influenza and SARS-CoV-2 viruses, or as a part of combination antiviral treatment.

Prophylactic Use of Antifibrinolytics During Pediatric Cardiac Surgery With Cardiopulmonary Bypass on Postoperative Bleeding and Transfusion: A Systematic Review and Meta-Analysis

OBJECTIVES

To determine the effect of intraoperative antifibrinolytics, including tranexamic acid (TXA), aminocaproic acid (EACA), or aprotinin, on bleeding in children undergoing cardiac surgery with cardiopulmonary bypass (CPB).

DATA SOURCES

Relevant articles were systematically searched from Ovid MEDLINE, Ovid EMBASE, CINAHL, Cochrane Library, and Web of Science to November 15, 2021.

STUDY SELECTION

Abstracts were screened, and full texts were reviewed using predetermined inclusion and exclusion criteria using the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline.

DATA EXTRACTION

A standardized data extraction tool was used.

DATA SYNTHESIS

Sixty-eight studies including 28,735 patients were analyzed. TXA compared with placebo resulted in a mean decrease in chest tube output of 9.1 mL/kg (95% CI, 6.0-12.3 mL/kg), I2 equals to 65.2%, p value of less than 0.001, platelet requirement of 2.9 mL/kg (95% CI, 0.1-5.8 mL/kg), I2 =72.5%, p value less than 0.001 and plasma requirement of 4.0 mL/kg (95% CI, 0.6-7.2 mL/kg), I2 equals to 94.5%, p value less than0.001. Aprotinin compared with placebo resulted in a mean decrease in chest tube output of 4.3 mL/kg (2.4-6.2 mL/kg), I2 equals to 66.3%, p value of less than 0.001, platelet transfusion of 4.6 mL/kg (95% CI, 0.6-8.6 mL/kg), I2 equals to 93.6%, p value of less than 0.001, and plasma transfusion of 7.7 mL/kg (95% CI, 2.1-13.2 mL/kg), I2 equals to 95.3%, p value of less than 0.001. EACA compared with placebo resulted in a mean decrease in chest tube output of 9.2 mL/kg (2.3-21.0 mL/kg), I2 equals to 96.4%, p value of less than 0.001, RBC transfusion of 7.2 mL/kg (95% CI, 2.4-12.1 mL/kg), I2 equals to 94.5%, p value equals to 0.002, and platelet transfusion of 10.7 mL/kg (95% CI, 2.9-18.5 mL/kg), I2 equals to 0%, p value of less than 0.001. No statistical difference was observed in chest tube output when TXA was compared with aprotinin. Subgroup analysis of cyanotic patients showed a significant decrease in chest tube output, platelet requirement, and plasma requirement for patients receiving aprotinin. Overall, the quality of evidence was moderate.

CONCLUSIONS

Antifibrinolytics are effective at decreasing blood loss and blood product requirement in children undergoing cardiac surgery with CPB although the quality of evidence is only moderate.

Multicenter International Survey on Cardiopulmonary Bypass Perfusion Practices in Adult Cardiac Surgery

OBJECTIVES

To assess current practice in adult cardiac surgery during cardiopulmonary bypass (CPB) across European and non-European countries.

DESIGN

International, multicenter, web-based survey including 28 multiple choice questions addressing hemodynamic and tissue oxygenation parameters, organ protection measures, and the monitoring and usage of anesthetic drugs as part of the anesthetic and perfusion practice during CPB.

SETTING

Online survey endorsed by the European Association of Cardiothoracic Anesthesiologists.

PARTICIPANTS

Representatives of anesthesiology departments in European and non-European adult cardiac surgical centers.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The survey was distributed via e-mail to European Association of Cardiothoracic Anesthesiologists members (n = 797) and kept open for 1 month. The response rate was 34% (n = 271). After exclusion of responses from the same centers and of incomplete answers, data from 202 cardiac centers in 56 countries, of which 67% of centers were university hospitals, were analyzed. Optimization of pump flows and tissue oxygenation parameters during CPB were applied by the majority of centers, with target flow rates of >2.2 L/min/m² in 93% (n = 187) of centers and mean arterial blood pressures between 51 and 90 mmHg in 85% (n = 172). Hemoglobin transfusion triggers were either individualized or between 7 and 8 g/dL in 92% (n = 186) of centers. Mixed venous oxyhemoglobin saturations were assessed routinely in 59% (n = 120) and lactate in 88% (n = 178) of cardiac surgery units. Noninvasive cerebral saturation monitoring was used in a subgroup of patients or routinely in 84% (n = 169) of sites, and depth-of-anesthesia monitoring was used routinely in 53% (n = 106). Transesophageal echocardiography and pulmonary artery catheters were used routinely or in subgroups of patients in 97% (n = 195) and 71% (n = 153) of centers, respectively. The preferred site for temperature monitoring was the nasopharynx in 66% (n = 134) of centers. Anesthetic techniques were variable, with 26% of centers (n = 52) using low-tidal-volume ventilation and 28% (n = 57) using continuous positive airway pressure during CPB. Volatile agents were used routinely as the only agent during CPB in 36% sites (n = 73) and propofol in 47% (n = 95). Other drugs routinely administered included magnesium in 45% (n = 91), steroids in 18% (n = 37), tranexamic acid in 88% (n = 177), and aprotinin in 15% (n = 30) of the centers.

CONCLUSION

This international CPB survey revealed that techniques for optimization of pump flow and oxygenation during CPB usually were applied. Furthermore, cerebral and hemodynamic monitoring devices were frequently used during CPB. However, most CPB-related anesthetic techniques and medications were more variable. More high-quality randomized controlled trials are needed to assess anesthetic techniques and organ protection.

Effectiveness and Safety of Aprotinin Use in Thoracic Aortic Surgery

OBJECTIVE

To determine the effectiveness and safety of aprotinin use in adult patients undergoing thoracic aortic surgery.

DESIGN

Single-center, retrospective study.

SETTING

All cases performed at a single university hospital.

PARTICIPANTS

Between January 2004 and December 2014, 846 adult patients underwent thoracic aortic surgery. Due to missing or duplicated data on primary outcomes, 314 patients were excluded. The final sample of 532 patients underwent surgery on the thoracic aorta.

INTERVENTIONS

The patients were divided in the following 2 groups: 107 patients (20.1%) received aprotinin during the surgery, which represented the study group, whereas the remaining 425 patients (79.9%) underwent surgery without the use of aprotinin.

MEASUREMENTS AND MAIN RESULTS

To adjust for patient selection and preoperative characteristics, a propensity score-matched analysis was conducted. Mean total blood loss at 12 hours after surgery was similar between the 2 groups. The blood product transfusion rates did not differ in the 2 groups, except for the rate of fresh frozen plasma transfusion being significantly higher in the aprotinin group. Re-exploration for bleeding and the incidence of a major postoperative bleeding event were similar between the groups. Rates of in-hospital mortality, renal failure, and cerebrovascular accidents did not show any statistically significant difference. Aprotinin did not represent a risk factor for mortality over the long term (hazard ratio 1.14, 95% confidence interval 0.62-2.08, p = 0.66).

CONCLUSIONS

The use of aprotinin demonstrated a limited effect in reducing postoperative bleeding and prevention of major bleeding events. Aprotinin did not adversely affect early outcomes and long-term survival.

A Randomized Trial of the Topical Effect of Antifibrinolytic Epsilon Aminocaproic Acid on Coronary Artery Bypass Surgery Without Cardiopulmonary Bypass

We assessed the effect of the topical application of epsilon-aminocaproic antifibrinolytic acid (EACA) on the pericardium of patients submitted to coronary artery bypass graft (CABG) without the use of cardiopulmonary bypass (CPB). This is a prospective, randomized, and double-blind study. We evaluated 26 patients with chronic coronary heart disease indicated for CABG without CPB (EACA and placebo groups). The analysis of the postoperative hematological results showed no difference between groups in hemoglobin and hematocrit. There was no difference between the groups regarding the postoperative bleeding through the drains in the first 24 hours, 48 hours, and accumulated loss until removal of drains. The use of EACA in patients undergoing CABG without CPB presented no difference in the reduction of the amount of bleeding and the need for blood transfusions.

Aprotinin revisited

In 2008, we saw the withdrawal of aprotinin from the US markets after preliminary results from a large, randomized clinical trial in Canada. This drug, a potent antifibrinolytic, was used primarily in complex and/or redo cardiac surgery as an adjunct to decrease postoperative bleeding and complications. The Canadian study raised questions previously brought up in similar studies-does aprotinin increase the risk of mortality and renal failure after cardiac surgery? Recently, a re-review of the Canadian data noted flaws in the study, as well as in the interpretation of the results. The present review revisits the aprotinin controversy.

Natural and engineered plasmin inhibitors: applications and design strategies

The serine protease plasmin is ubiquitously expressed throughout the human body in the form of the zymogen plasminogen. Conversion to active plasmin occurs through enzymatic cleavage by plasminogen activators. The plasminogen activator/plasmin system has a well-established function in the removal of intravascular fibrin deposition through fibrinolysis and the inhibition of plasmin activity; this has found widespread clinical use in reducing perioperative bleeding. Increasing evidence also suggests diverse, although currently less defined, roles for plasmin in a number of physiological and pathological processes relating to extracellular matrix degradation, cell migration and tissue remodelling. In particular, dysregulation of plasmin has been linked to cancer invasion/metastasis and various chronic inflammatory conditions; this has prompted efforts to develop inhibitors of this protease. Although a number of plasmin inhibitors exist, they commonly suffer from poor potency and/or specificity of inhibition that either results in reduced efficacy or prevents clinical use. Consequently, there is a need for further development of high-affinity plasmin inhibitors that maintain selectivity over other serine proteases. This review summarises clearly defined and potential applications for plasmin inhibition. The properties of naturally occurring and engineered plasmin inhibitors are discussed in the context of current knowledge regarding plasmin structure, specificity and function. This includes design strategies to obtain the potency and specificity of inhibition in addition to controlled temporal and spatial distribution tailored for the intended use.

Effects of aprotinin on short-term and long-term outcomes after coronary artery bypass grafting surgery

BACKGROUND

Recent studies demonstrated that aprotinin use would increase the short-term and long-term mortality and complications after coronary artery bypass grafting (CABG). This study was to investigate effects of aprotinin during isolated primary CABG on short-term and long-term outcomes in Chinese patients.

METHODS

We studied 5,103 consecutive Chinese patients who underwent isolated primary CABG from 1999 to 2005. Of all the patients, 4,122 received aprotinin during operation (aprotinin group) and 981 received no aprotinin or other antifibrinolytic therapy (control group). Short-term and long-term mortality and major complications were analyzed with multivariate regression analysis. Propensity adjustment method was used to minimize the selection bias between the two groups, and propensity matching method was used to yield two well-matched groups for further comparison.

RESULTS

Blood loss after operation was significantly reduced in the aprotinin group compared with the control group (p < 0.001). Aprotinin use was neither associated with the perioperative mortality (p = 0.45, relative risk, 1.34) or major complications, nor was it associated with long-term mortality (p = 0.21, relative risk, 1.26) and major adverse cardiac and cerebrovascular events (p = 0.82, relative risk, 0.98). After propensity adjustment for the baseline characteristics, we obtained similar results. In addition, comparison between the two well-matched groups showed no significant difference either in baseline characteristics or in short-term and long-term outcomes.

CONCLUSIONS

Aprotinin use during isolated primary CABG reduced blood loss significantly, but was not associated with short-term or long-term mortality and complications. Aprotinin use in relatively low-risk CABG patients was effective and safe in a Chinese (Asian) population.

Lessons from aprotinin: is the routine use and inconsistent dosing of tranexamic acid prudent? Meta-analysis of randomised and large matched observational studies

In view of the safety concerns that led to the withdrawal of aprotinin, should antifibrinolytics be used indiscriminately in cardiac surgery? This meta-analysis examines the efficacy and safety profile of tranexamic acid, and in comparison to aprotinin. We identified randomised trials and large observational studies investigating the use tranexamic acid from January 1995 to January 2009 using Pubmed/Cochrane search engine and included them in a two-tier meta-analysis. There were 25 randomised trials and four matched studies with a total of 5411 and 5977 patients, respectively, reporting tranexamic acid use in varying dosages. Tranexamic acid is administered intravenously either as single dose, infusion or both, sometimes added to pump prime or applied topically. Total intravenous dose of tranexamic acid varies from 1g to 20 g, administered over a period of 20 min to 12h. Compared with placebo, tranexamic acid is associated with a lower mean difference in blood loss (random effect -298 ml, 95% confidence [CI] -367 to -229, p<0.001) and decease in rates of re-operation for bleeding by 48%, transfusion of packed red cell by 47% and use of haemostatic blood products by 67%. A non-significant tendency for postoperative neurological events but a decrease in operative mortality was observed in patients treated with tranexamic acid compared with non-treatment group. Compared to aprotinin, tranexamic acid has less effective blood-conserving effect and mortality risk. Given the potential to increase neurological complications, the current trend towards indiscriminate use of tranexamic acid for all cardiac patients needs to be re-evaluated. Further studies are needed to clarify the neurological risk, appropriate indications and dosing of tranexamic acid.

Aprotinin in severe acute pancreatitis

Aprotinin, a Kunitz protease inhibitor, has a wide inhibitory action with particular activity against trypsin, chymotrypsin and kallikrein, making it theoretically attractive in ameliorating the effects of acute pancreatitis. Its use in acute pancreatitis has been studied for the last 50 years with disappointing results. In this paper, we review the previous studies and argue that all the studies have not been adequately powered, have inappropriate end-points, but most importantly have not attained adequate plasma and peritoneal levels of aprotinin to produce sufficient inhibitory activity. We hypothesise that a well-powered study with adequate aprotinin dosing may clarify its clinical benefit in severe acute pancreatitis.

Social deprivation and prognostic benefits of cardiac surgery: observational study of 44 902 patients from five hospitals over 10 years

OBJECTIVE

To assess the effects of social deprivation on survival after cardiac surgery and to examine the influence of potentially modifiable risk factors.

DESIGN

Analysis of prospectively collected data. Prognostic models used to examine the additional effect of social deprivation on the end points.

SETTING

Birmingham and north west England.

PARTICIPANTS

44 902 adults undergoing cardiac surgery, 1997-2007.

MAIN OUTCOME MEASURES

Social deprivation with census based 2001 Carstairs scores. All cause mortality in hospital and at mid-term follow-up.

RESULTS

In hospital mortality for all cardiac procedures was 3.25% and mid-term follow-up (median 1887 days; range 1180-2725 days) mortality was 12.4%. Multivariable analysis identified social deprivation as an independent predictor of mid-term mortality (hazard ratio 1.024, 95% confidence interval 1.015 to 1.033; P<0.001). Smoking (P<0.001), body mass index (BMI, P<0.001), and diabetes (P<0.001) were associated with social deprivation. Smoking at time of surgery (1.294, 1.191 to 1.407, P<0.001) and diabetes (1.305, 1.217 to 1.399, P<0.001) were independent predictors of mid-term mortality. The relation between BMI and mid-term mortality was non-linear and risks were higher in the extremes of BMI (P<0.001). Adjustment for smoking, BMI, and diabetes reduced but did not eliminate the effects of social deprivation on mid-term mortality (1.017, 1.007 to 1.026, P<0.001).

CONCLUSIONS

Smoking, extremes of BMI, and diabetes, which are potentially modifiable risk factors associated with social deprivation, are responsible for a significant reduction in survival after surgery, but even after adjustment for these variables social deprivation remains a significant independent predictor of increased risk of mortality.

Aprotinin and renal dysfunction

Aprotinin is a polypeptide serine protease inhibitor used to prevent bleeding and need for transfusions in patients having heart surgery. A recent analysis of an observational study data set suggested the use of aprotinin was associated with an increased risk of developing renal failure. The present article reviews the data from basic science studies in tissues, animals and man together with the data from observational studies and randomised controlled trials. The interpretation of the data is hampered owing to the use of different endpoints to describe mild/moderate renal impairment. Nonetheless, the evidence points to aprotinin use being associated with a transient small rise in plasma creatinine concentration in certain patients. There is no evidence for an increased risk of developing new renal failure requiring dialysis/renal replacement therapy.

Biostatistical aspects for the use of evidence based medicine in health technology assessment

Health systems throughout the world are increasingly concerned with the evaluation of the effectiveness and cost-effectiveness of pharmaceuticals (and health technologies more generally), in order to enhance the extent to which scarce health resources are used efficiently. Regulatory processes designed to demonstrate efficacy, quality and safety are added to the concept of efficiency or value for money. These regulatory processes serve to identify and ensure that a product does indeed have a therapeutic effect; that it is manufactured to acceptable standards; and that it does not bring undue hazard to patients with use. A subsequent appraisal process considers if and where society might rationally bring the intervention into usage. It may be efficient for a health system to adopt a less effective but less costly treatment where overall limited resources may be allocated in such a way as to achieve greater health benefit. In this article, I consider aspects of the statistical synthesis of evidence intended to support decisions on pharmaceutical reimbursement.

Aprotinin in primary cardiac surgery: operative outcome of propensity score-matched study

BACKGROUND

Some recent multicenter series have questioned the safety of aprotinin in primary cardiac operations. We report a large, single-center experience with aprotinin therapy in primary cardiac operations and discuss the limitations and potential confounders of current treatment strategies.

METHODS

We compared myocardial infarction, neurologic events, renal insufficiency, and operative death after first-time coronary or valve procedures, or both, in 3334 patients treated with full-dose aprotinin with 3417 patients not treated with aprotinin who underwent operation between March 1998 and January 2007. Further analysis was performed for 341 propensity score-matched pairs.

RESULTS

There were substantial differences between the groups. Aprotinin patients were higher risk on account of older age, unstable symptoms, poor ejection fraction, preoperative hemodynamic support, emergency/urgent operations, and combined coronary/valve operations. Postoperative bleeding and blood product transfusion were considerably reduced in aprotinin patients, as was median duration of mechanical ventilation. Aprotinin was neither a predictor of postoperative myocardial infarction, renal insufficiency, neurologic dysfunction, or operative death. Achieving parity between the groups by propensity score matching eliminated the elevated rates of postoperative renal insufficiency, neurologic dysfunction, and operative death observed in aprotinin patients in the unmatched comparison. These adverse outcomes were evenly distributed between matched groups. Conversely, blood transfusion had univariate associations with all adverse outcome measures.

CONCLUSIONS

Full-dose aprotinin use was not associated with myocardial infarction, neurologic dysfunction, renal insufficiency, or death after coronary or valve operations. We observed less postoperative bleeding and blood product transfusion, and early extubation with the use of aprotinin.