Pharmacological prophylaxis of bleeding in surgical patients treated with aspirin

Safe and effective thrombolysis in free flap salvage: Intra-arterial urokinase infusion

Despite the high success rate in reconstruction using free tissue transfer, flap failure is often caused by microvascular thrombosis. In a small percentage of cases with complete flap loss, a salvage procedure is performed. In the present study, the effectiveness of intra-arterial urokinase infusion through the free flap tissue was investigated to develop a protocol to prevent thrombotic failure. The retrospective study evaluated the medical records of patients who underwent salvage procedure with intra-arterial urokinase infusion after reconstruction with free flap transfer between January 2013 and July 2019. Thrombolysis with urokinase infusion was administered as salvage treatment for patients who experienced flap compromise more than 24 hours after free flap surgery. Because of an external venous drainage through the resected vein, 100,000 IU of urokinase was infused into the arterial pedicle only into the flap circulation. A total of 16 patients was included in the present study. The mean time to re-exploration was 45.4 hours (range: 24-88 hours), and the mean quantity of infused urokinase was 69,688 IU (range: 30,000-100,000 IU). 5 cases presented with both arterial and venous thrombosis, while 10 cases had only venous thrombosis and 1 case had only arterial thrombosis; in a study of 16 patients undergoing flap surgery, 11 flaps were found to have survived completely, while 2 flaps experienced transient partial necrosis and 3 were lost despite salvage efforts. In other word, 81.3% (13 of 16) of flaps survived. Systemic complications, including gastrointestinal bleeding, hematemesis, and hemorrhagic stroke, were not observed. The free flap can be effectively and safely salvaged without systemic hemorrhagic complications using high-dose intra-arterial urokinase infusion within a short period of time without systemic circulation, even in delayed salvage cases. Urokinase infusion results in successful salvage and low rate of fat necrosis.

Lack of Complications in Minor Skin Lesion Excisions in Patients Taking Aspirin or Warfarin Products

Many patients undergoing surgical procedures take medications that influence the coagulation system. It is common practice to discontinue the use of aspirin and warfarin products 7 to 10 days before any major surgical procedure. However, there is some controversy as to whether these medications should be discontinued for minor dermatological procedures. Our aim was to study the incidence of complications in patients receiving aspirin or warfarin and undergoing minor dermatological procedures. Two thousand three hundred twenty-six patients, operated on by a single surgeon, were studied for complications. Warfarin was used by 28 patients, 228 took aspirin, and the remainder took neither. There was no difference in the complication rate among the three groups as long as the surgeon diligently obtained hemostasis. It appears that patients taking aspirin or warfarin do not need to discontinue these medications before minor dermatological procedures.

Antiplatelet drug use preceding the onset of intracerebral hemorrhage is associated with increased mortality

Recent studies highlight the contribution of antiplatelet therapy to clinical severity and increased mortality of intracerebral hemorrhage (ICH) but results are discrepant. The aim of this report was to evaluate the association between antiplatelet drug use preceding the onset of ICH and the mortality, assessed at regular intervals, among patients with acute ICH. We analyzed data from a randomized study which enrolled consecutive patients with a documented acute ICH to evaluate the efficacy of intermittent pneumatic compression of the legs in venous thrombosis prevention. Clinical characteristics and treatment used before the onset of ICH were checked at the time of inclusion. Mortality was assessed at regular intervals until 3 months after ICH diagnosis. Among 138 patients included in this report, 30 were current users of antiplatelet therapy at the time of ICH; they were significantly older and less frequently heavy drinkers than non-users of antiplatelet drugs. Mortality rates were 20% at 8 days, 40% at 1 month, and 47% at 3 months among antiplatelet drug users compared with 6.5%, 13% and 19% among non-users. The corresponding estimated risks for mortality related to antiplatelet drug use were 3.6 (95% CI 1.1-12), 4.5 (95% CI 1.8-11), and 3.6 (95% CI 1.5-8.6). Adjusted for age, hypertension and alcohol over use, antiplatelet therapy remained significantly associated with an increased mortality rate of acute ICH. Current antiplatelet drug use preceding the onset of ICH is associated with increased short-term ICH mortality, independently of age.

Blood conservation strategies in cardiac surgery

Despite the continuous efforts to increase the safety of blood components, red blood cell transfusions remain associated with some risks and side effects. Therefore, numerous techniques have been developed to decrease blood use, but they also carry risks and bear costs. Most of them are frequently used in cardiac surgery, which still consumes a large part of the available blood supply. Among western countries the use of alternative techniques, but also transfusion practice, has been shown to vary markedly. 'Blood conservation' is a global concept engulfing all possible strategies aimed at reducing patients' exposure to allogeneic blood components. The development of the 'best strategy' consists of the selection of those techniques that are most appropriate to the local specific situation. It implies the establishment of a reliable system, collecting data both at the surgical team and at the medical level.

Low-dose aspirin before intracranial surgery--results of a survey among neurosurgeons in Germany

BACKGROUND

Increasing numbers of patients presenting for intracranial surgery are receiving concurrent medication with low-dose aspirin, leading to dysfunctional circulating platelets, which might increase the peri-operative risk of bleeding.

OBJECTIVE

To survey the opinions and working practices of neurosurgical facilities in Germany regarding patients who present with low-dose aspirin medication before elective intracranial surgery. Methods. Questionnaires were sent to 210 neurosurgical facilities asking five main questions: (1) the adherence of any policy of stopping aspirin pre-operatively, (2) the personal risk assessment for patients with brain surgery under low-dose aspirin medication, (3) the preferred method of treatment for excessive bleeding in this context, (4) personal knowledge of haemorrhagic complications in this group of patients, and (5) the characteristics of the neurosurgical units concerned.

RESULTS

There were 138 (65.7%) valid responses. Of the respondents, 111 (80.4%) had a departmental policy for the discontinuation of pre-operative aspirin treatment. The mean time for discontinuation of aspirin pre-operatively was 7.3 days (range: 0-21 days). 107 respondents (77.5%) considered that patients taking low-dose aspirin were at increased risk for excessive peri-operative haemorrhage, and 80 (58%) reported having personal experience of such problems. Ninety-seven respondents (70.3%) would use special medical therapy, preferably desmopressin, if haemorrhagic complications developed intra-operatively. The mean amount of intracranial operations per year in each neurosurgical facility was 494 (range: 50-1700).

CONCLUSIONS

The majority of neurosurgical facilities in Germany have distinct departmental policies concerning the discontinuation of low-dose aspirin pre-operatively, with an average of 7.3 days. Three-quarter of the respondents felt that aspirin was a risk factor for haemorrhagic complications associated with intracranial procedures, and more than half of the interviewees reported having personal experience of such problems. Various medicamentous methods of counteracting aspirin-induced platelet dysfunction and excessive bleeding in this context are discussed and evaluated.

Low-dose aspirin before spinal surgery: results of a survey among neurosurgeons in Germany

The main problem faced by the increasing numbers of patients presenting for spinal surgery are receiving concurrent medication with low-dose aspirin, leading to dysfunctional circulating platelets. The contribution of low-dose aspirin to increased peri-operative risk of bleeding and blood loss is a contentious issue with conflicting published results from different surgical groups. Data from neurosurgical spine patients is sparse, but aspirin has been identified as an important risk factor in the development of post-operative hematoma following intracranial surgery. We surveyed the opinions and working practices of the neurosurgical facilities performing spinal operations in Germany regarding patients who present for elective spinal surgery. Identical questionnaires were sent to 210 neurosurgical facilities and proffered five main questions: (1) the adherence of any policy of stopping aspirin pre-operatively, (2) the personal risk assessment for patients with spinal surgery under low-dose aspirin medication, (3) the preferred method of treatment for excessive bleeding in this context, (4) personal knowledge of hemorrhagic complications in this group of patients, and (5) the characteristics of the neurosurgical units concerned. There were 145 (69.1%) responses of which 142 (67.6%) were valid. Of the respondents, 114 (80.3%) had a (written) departmental policy for the discontinuation of pre-operative aspirin treatment, 28 (19.7%) were unaware of such a policy. The mean time suggested for discontinuation of aspirin pre-operatively was 6.9 days (range: 0-21 days), with seven respondents who perform the operations despite the ongoing aspirin medication. Ninety-four respondents (66.2%) considered that patients taking low-dose aspirin were at increased risk for excessive peri-operative hemorrhage or were indetermined (8.6%), and 73 (51.4%) reported having personal experience of such problems. Ninety-two respondents (65.5%) would use special medical therapy, preferably Desmopressin alone or in combination with other blood products or prohemostatic agents (46.1%), if hemorrhagic complications developed intra- or post-operatively. The average number of spinal operations per year in each service was 607.9 (range: 40-1,500). Despite the existence of distinct departmental policies concerning the discontinuation of low-dose aspirin pre-operatively in the majority of neurosurgical facilities performing spinal operations, there is a wide range of the moment of this interruption with an average of 7 days. Two-thirds of the respondents felt that aspirin was a risk factor for hemorrhagic complications associated with spinal procedures, and more than half of the interviewees reported having personal experience of such problems. Finally, various medicamentous methods of counteracting aspirin-induced platelet dysfunction and excessive bleeding in this context are elicited, discussed and evaluated.

Anticoagulation therapy in microsurgery: a review

The advent of microsurgical tissue transfer including replantation greatly has expanded the scope of reconstructive surgery. There are few recent innovations in anticoagulation therapies for microsurgery, however, and anastomotic thrombosis remains an occasional cause of surgical failure. No consensus exists on the ideal anticoagulation protocol for microsurgery. This article reviews major pharmacologic modalities of anticoagulation, delineates the mechanism of action and study of efficacy of each agent, and compares the risks and benefits of popular anticoagulation therapies. Finally, it examines available human outcomes-based data and attempts to provide a glimpse of the future direction of microsurgical anticoagulation research.

Venous Thromboembolism in the ICU and Reversal of Bleeding on Anticoagulants

Venous thromboembolic disease is a very common complication in the ICU. This article reviews incidence, prevention, and therapy related to venous thromboembolism, including both deep venous thrombosis and pulmonary embolism. Special diagnostic and treatment considerations in the ICU setting are highlighted. The increased use of antithrombotic agents has led to an increased number of patients who experience bleeding complications on anticoagulant therapy. This review also addresses the methods of reversing various anticoagulants.

Outcome of aspirin use during excision of cutaneous lesions

The perioperative course of 253 patients undergoing excision of cutaneous and subcutaneous lesions by the same surgeon was evaluated, comparing patients using aspirin and those not using aspirin. Intraoperative methods of obtaining hemostasis and the incidence of postoperative complications were evaluated. Suture ligatures were used more frequently in the group using aspirin, but there was no statistical difference in the use of electrocautery. There was also no difference in the incidence of wound dehiscence, erythema, or hematoma. The outcome of excision of cutaneous and subcutaneous lesions under local anesthesia is not affected by patients using aspirin.

Complications of minor cutaneous surgery in patients under anticoagulant treatment

Anticoagulant use is common in the elderly population. The role of these medications in the postoperative period is not well defined. We designed a prospective study to evaluate the incidence of postoperative complications in patients taking aspirin and warfarin. A prospective study was performed on 102 patients undergoing minor cutaneous plastic surgery. The number of subjects using regular aspirin, warfarin, and that of the patients with no anticoagulant medication were 37, 21, and 44, respectively. Complications were defined as minor, moderate, or major based on predetermined criteria. Of patients taking warfarin, 57% had some complication, significantly more than complications in the control group. The number of major complications in the warfarin group was significantly higher than those of the control and aspirin groups (p = 0.02). Also, the total number of complications in the warfarin group was significantly higher than the control group, but there was no significant difference between aspirin and control groups (p > 0.05). Cutaneous surgery in patients who receive warfarin is associated with a risk of major complication, but this risk does not exist in the patients receiving chronic aspirin treatment.

Effects of desmopressin on thrombogenesis in aspirin-induced platelet dysfunction

Aspirin causes a coagulation disorder. Desmopressin has haemostatic effects by increasing the plasma levels of coagulation factor VIII and von Willebrand factor. The precise effects of desmopressin on thrombogenesis are not known. In an in vivo model, we investigated the effect of the drug on thrombus formation and platelet function after aspirin use. Male Lewis rats weighing 250-300 g were used. Four groups with 10 animals each were formed: control, aspirin, desmopressin and aspirin + desmopressin. In each animal, the femoral artery was dissected. A thrombogenic vessel injury was created by inverting a full thickness portion of the proximal edge of the incised artery into the lumen. The following parameters were measured: maximum thrombus size, time period until maximum thrombus size was reached and overall platelet function. In addition, the thrombi generated were investigated histologically. Thrombus formation time was significantly shorter with desmopressin compared with the animals treated with aspirin (P < 0.0001) and controls (P = 0.008). Maximum thrombus size was larger in the desmopressin and desmopressin + aspirin groups when compared with the group treated with aspirin only. Overall platelet function was significantly enhanced with desmopressin compared with controls (P = 0.025) and with aspirin (P < 0.0001). The differences were confirmed histologically. In conclusion, desmopressin significantly accelerates thrombus formation in aspirin-treated animals. It can also re-establish thrombus size after the use of aspirin. Overall platelet function is significantly increased by desmopressin.

[Does the time between preoperative interruption of aspirin intake and operation influence postoperative blood loss and transfusion requirement in coronary artery bypass graft?]

OBJECTIVE

Impact of the interval between interruption of aspirin intake and surgery on postoperative bleeding and transfusion in coronary artery bypass graft (CABG), with extracorporeal circulation (ECC).

STUDY DESIGN

Retrospective study.

PATIENTS AND METHODS

Four hundred and twelve patients having undergone CABG were retrospectively reviewed. Three groups were evaluated according to the length of the interval defined above: Group I (< 3 days), Group II (3-7 days), Group III (> 7 days or without aspirin intake). Postoperative blood loss at 3rd, 6th, 12th, and 24th hour and transfusion requirements were assessed for the 3 groups. Aprotinin (low dose, 2 M KIU) was systematically included in the priming of the ECC circuit.

RESULTS

There were no significant differences among groups for weight, size, duration of ECC, and number of bypasses. No significant correlation was noted among the 3 groups for postoperative blood loss and transfusion. Multivariate analysis showed that factors associated to a higher risk of excessive bleeding were ECC duration and number of arterial grafts. Factors associated with a higher risk of transfusion were: emergency, minimum patient temperature during ECC, weight and preoperative haemoglobin level. Aspirine intake was not associated with an increase of bleeding or transfusion.

CONCLUSION

Our study showed that in our practice using systematic low dose of aprotinin when priming the ECC circuit, aspirin did not significantly increase bleeding or transfusion requirements in CABG with ECC, whatever the interval between interruption of aspirin intake and surgery. Consequently, in our practice, aspirin intake is interrupted on hospitalisation, one day before surgery.

Examining the evidence in anesthesia literature: a critical appraisal of systematic reviews

Systematic reviews are structured reviews that use scientific strategies to reduce bias in the collection, appraisal, and interpretation of relevant studies. We undertook a systematic review of published systematic reviews in perioperative medicine to summarize the areas currently covered by this type of literature, to evaluate the quality of systematic reviews in this field, and to assess some of the methodologic and reporting issues that are unique to systematic reviews. Computerized bibliographic databases, citation review, and hand searches were performed to identify eligible articles. Quality was assessed using the Overview Quality Assessment Questionnaire. Eight-two systematic reviews were found. Reviews in perioperative medicine tended to evaluate prophylactic or therapeutic interventions. No differences were seen in quality between reviews published in anesthesia and nonanesthesia journals. Nearly half of all systematic reviews had only minor or minimal flaws; however, methods can be improved with expanded search strategies, use of least two reviewers to assess each study, use of validated methods to evaluate quality, and assessment of potential sources of bias.

IMPLICATIONS

The quality of systematic reviews relating to perioperative medicine was examined systematically and found to be similar in quality to those in other specialties. Adoption of recently published criteria on writing and methods could further improve this type of literature.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have prompted re-consideration of the use of allogeneic (blood from an unrelated donor) blood transfusion.

OBJECTIVES

To assess the effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid, and epsilon aminocaproic acid, on peri-operative red blood cell (RBC) transfusion.

SEARCH STRATEGY

We searched MEDLINE (to May 1998), EMBASE (to December 1997), web sites of international health technology assessment agencies (to May 1998). References in identified trials and review articles were checked and authors contacted to identify any additional studies.

SELECTION CRITERIA

Randomised controlled trials of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

We found 61 trials of aprotinin (7027 participants). Aprotinin reduced the rate of RBC transfusion by a relative 30% (RR=0.70: 95%CI: 0.64 to 0.76). The average absolute risk reduction (ARR) was 20.4% (95%CI: 15.6% to 25.3%). On average, aprotinin use saved 1.1 units of RBC (95%CI: 0.69 to 1.47) in those requiring transfusion. Aprotinin also significantly reduced the need for re-operation due to bleeding (RR=0.40: 95%CI: 0.25 to 0.66). We found 18 trials of tranexamic acid (TXA) (1,342 participants). TXA reduced the rate of RBC transfusion by a relative 34% (RR=0.66: 95%CI: 0.54 to 0.81). This represented an ARR of 17.2% (95%CI: 8.7% to 25.7%). TXA use resulted in a saving of 1.03 units of RBC (95%CI: 0.67 to 1.39) in those requiring transfusion. We found four trials of epsilon aminocaproic acid (EACA) (208 participants). EACA use resulted in a statistically non-significant reduction in RBC transfusion (RR=0.48: 95%CI: 0.19 to 1.19). Comparisons between agents Eight trials made 'head-to-head' comparisons between TXA and aprotinin. There was no significant difference between the two drugs in the rate of RBC transfusion: RR=1.21 (95%CI: 0.83 to 1.76) for TXA compared to aprotinin. Adverse Effects Aprotinin did not seem to be associated with an excess risk of adverse effects, including thrombo-embolic events (thrombosis RR=0.64: 95%CI: 0.31 to 1.31) and renal failure (RR=1.19: 95%CI: 0.79 to 1.79). Fewer data were available for TXA and EACA.

REVIEWER'S CONCLUSIONS

From this review it appears that aprotinin reduces the need for red cell transfusion, and the need for re-operation due to bleeding, without serious adverse effects. However, there was significant heterogeneity in trial outcomes, and some evidence of publication bias. Similar trends were seen with TXA and EACA, although the data were rather sparse. The poor evaluation of these latter drugs is unfortunate as results suggest they may be equally as effective as aprotinin, but are significantly cheaper. The evidence reviewed here supports the use of aprotinin in cardiac surgery. Further small trials of this drug are not warranted. Future trials should be large enough to compare the efficacy and cost-effectiveness of aprotinin with that of TXA and EACA.