Aprotinin use in thoracic aortic surgery: Safety and outcomes

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.

Pulmonary complications of cardiopulmonary bypass

Pulmonary complications after the use of extracorporeal circulation are common, and they range from transient hypoxemia with altered gas exchange to acute respiratory distress syndrome (ARDS), with variable severity. Similar to other end-organ dysfunction after cardiac surgery with extracorporeal circulation, pulmonary complications are attributed to the inflammatory response, ischemia-reperfusion injury, and reactive oxygen species liberated as a result of cardiopulmonary bypass. Several factors common in cardiac surgery with extracorporeal circulation may worsen the risk of pulmonary complications including atelectasis, transfusion requirement, older age, heart failure, emergency surgery, and prolonged duration of bypass. There is no magic bullet to prevent or treat pulmonary complications, but supportive care with protective ventilation is important. Targets for the prevention of pulmonary complications include mechanical, surgical, and anesthetic interventions that aim to reduce the contact activation, systemic inflammatory response, leukocyte sequestration, and hemodilution associated with extracorporeal circulation.

Trends in aortic dissection hospitalizations, interventions, and outcomes among medicare beneficiaries in the United States, 2000-2011

BACKGROUND

The epidemiology of aortic dissection (AD) has not been well described among older persons in the United States. It is not known whether advancements in AD care over the last decade have been accompanied by changes in outcomes.

METHODS AND RESULTS

The Inpatient Medicare data from 2000 to 2011 were used to determine trends in hospitalization rates for AD. Mortality rates were ascertained through corresponding vital status files. A total of 32 057 initial AD hospitalizations were identified. The overall hospitalization rate for AD remained unchanged at 10 per 100 000 person-years. For 30-day and 1-year mortality associated with AD, the observed rate decreased from 31.8% to 25.4% (difference, 6.4%; 95% confidence interval [CI], 6.2-6.5; adjusted, 6.4%; 95% CI, 5.7-6.9) and from 42.6% to 37.4% (difference, 5.2%; 95% CI, 5.1-5.2; adjusted, 6.2%; 95% CI, 5.3-6.7), respectively. For patients undergoing surgical repair for type A dissections, the observed 30-day mortality decreased from 30.7% to 21.4% (difference, 9.3%; 95% CI, 8.3-10.2; adjusted, 7.3%; 95% CI, 5.8-7.8) and the observed 1-year mortality decreased from 39.9% to 31.6% (difference, 8.3%; 95% CI, 7.5-9.1%; adjusted, 8.2%; 95% CI, 6.7-9.1). The 30-day mortality decreased from 24.9% to 21% (difference, 3.9%; 95% CI, 3.5-4.2; adjusted, 2.9%; 95% CI, 0.7-4.4) and 1-year decreased from 36.4% to 32.5% (difference, 3.9%; 95% CI, 3.3-4.3; adjusted, 3.9%; 95% CI, 2.5-6.3) for surgical repair of type B dissection.

CONCLUSIONS

Although AD hospitalization rates remained stable, improvement in mortality was noted, particularly in patients undergoing surgical repair.

Bleeding and management of coagulopathy

Bleeding after cardiac surgery remains a significant problem, increasing both length of stay and mortality, and is caused by multiple factors including dilutional changes, ongoing fibrinolysis, and platelet dysfunction. The evaluation of coagulopathy is problematic because of the long turnaround time of standard coagulation tests. Algorithms involving point of care testing, including thromboelastography and thromboelastometry, have been published; all have the potential to reduce transfusion requirements. Massive transfusion coagulopathy that occurs in trauma can also be seen in complex aortic surgery and other massive bleeding patients and should prompt consideration of a transfusion protocol involving fixed ratios of fresh frozen plasma, platelets, and red blood cells. Pharmacologic agents such as antifibrinolytics are commonly administered, but a multimodal approach to management is important. Recombinant and purified coagulation products are being studied and provide clinicians specific agents to treat targeted deficiencies. A general multi-modal approach is required and recommendations are made for the management of bleeding and coagulopathy in cardiac surgical patients.

Managing fibrinolysis without aprotinin

Cardiopulmonary bypass increases perioperative bleeding and produces a consumptive coagulopathy, which is defined as the simultaneous production of thrombin and fibrinolysis. Thrombin formation and fibrinolysis primarily occur in the surgical wound and peak at the time heparin is reversed by protamine. Neither aprotinin nor lysine analogs successfully control bleeding in many complex procedures, reoperations, aortic resections, or in implantations of mechanical circulatory devices. This analysis reviews the mechanisms involved and current treatment protocols, with the conclusion that changes in treatment protocols rather than use of a specific anti-fibrinolytic drug may provide better control of bleeding in these patients.

Aprotinin attenuates genomic expression variability following cardiac surgery

BACKGROUND

Aprotinin was the subject of recent controversy regarding adverse clinical outcomes following cardiac surgery. We compared the role of Aprotinin and epsilon-aminocaproic acid on clinical outcomes and the attenuation of the postcardiopulmonary bypass (CPB) response at the genomic expression and cytokine (protein) level.

METHODS

Thirty-nine low-risk patients undergoing coronary revascularization (CABG) and/or valve procedures using cardiopulmonary CPB were enrolled into a prospective cohort study. Aprotinin or epsilon-aminocaproic acid was administered to patients. Gene expression was assessed from whole blood mRNA samples collected preoperatively (PRE) and 6 hours (6H) postoperatively. Validation of gene expression was performed with SYBR Green real-time polymerase chain reaction. Cytokine values were quantified from serum preoperatively and postoperatively at 6 H and 4 days and analyzed in a blinded fashion.

RESULTS

No difference was detected in baseline characteristics. Inflammatory markers measured did not reveal significant difference between patients receiving Aprotinin (APR) and those receiving epsilon-aminocaproic acid (Amicar). Intraoperative parameters and postoperative outcomes were not significantly different. Compared with PRE samples, 6H samples had 264 upregulated and 548 downregulated genes uniquely in the APR group compared to 4826 upregulated and 1114 downregulated genes uniquely in the Amicar group (p < 0.001). Compared to patients in the Amicar group, APR patients had significantly different gene expression pathways involving NF-kappabeta regulation, programmed cell death and cell-cell adhesion. None of the patients developed postoperative stroke, myocardial infarction, or systemic infections.

CONCLUSIONS

Aprotinin leads to significantly less genomic expression variability following CPB compared to Amicar and has a differential effect on specific genomic pathways.

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.

Aprotinin in Cardiac Surgery: A Review of Conventional and Novel Mechanisms of Action

Induction of the coagulation and inflammatory cascades can cause multiorgan dysfunction after cardiopulmonary bypass (CPB). In light of these observations, strategies that can stabilize the coagulation process as well as attenuate the inflammatory response during and after cardiac surgery are important. Aprotinin has effects on hemostasis. In addition, aprotinin may exert multiple biologically relevant effects in the context of cardiac surgery and CPB. For example, it decreases neutrophil and macrophage activation and chemotaxis, attenuates release and activation of proinflammatory cytokines, and reduces oxidative stress. Despite these perceived benefits, the routine use of aprotinin in cardiac surgery with CPB has been called into question. In this review, we examined this controversial drug by discussing the classical and novel pathways in which aprotinin may be operative in the context of cardiac surgery.

Safety of Thoracic Aortic Surgery in the Present Era

BACKGROUND

Advances in graft materials, hemostasis, and surgical techniques have facilitated surgery on the thoracic aorta. We investigate the current safety level of these operations--for the purposes of enabling risk/benefit decisions for surgery and also to serve as a benchmark for comparison with emerging endovascular approaches.

METHODS

Five hundred six consecutive patients (315 male, 191 female; aged 14 to 91 years [mean, 61]) underwent surgery on the thoracic aorta at one institution from 1995 to 2004. In all, 360 operations involved the ascending and arch (71.1%) and 130 (25.7%) involved the descending or thoracoabdominal aorta, or both, and 16 (3.2%) were classified as miscellaneous aortic operations. Clinical data collected prospectively were analyzed retrospectively using chi2 and multivariable logistic regression statistics for the outcomes reoperation for bleeding, perioperative (hospital or 30-day) mortality and stroke. Midterm survival was assessed by Kaplan-Meier methodology.

RESULTS

Mortality for elective operations on the ascending/arch was 3.0%; mortality for elective operations on the descending aorta was 2.9%. Mortality for elective thoracoabdominal operations was 11.9%. Mortality for all operations was 8.6%. Probability of stroke was 3.0% for ascending/arch, 4.2% for descending, and 2.1% for thoracoabdominal operations. The paraplegia rate was 7.3% for all descending and thoracoabdominal operations. Age and emergency operation predicted increased risk of death, stroke, and reoperation for bleeding. For young patients (less than 55 years old) having elective ascending/arch operations, freedom from permanent complications of operation (death, stroke, paraplegia) was 98%. Overall survival at 1, 3, and 5 years was 84.7%, 78.3%, and 72.5%, respectively.

CONCLUSIONS

Aortic surgery is quite safe in the current era and leads to good long-term survival for this patient group. These data support prophylactic replacement of the thoracic aorta in patients with poor expected natural history (based on aneurysm size or symptoms). As catheter-based therapies proliferate, surgical data provide a benchmark that must be equaled or exceeded by newer endovascular approaches.