Postoperative Thrombotic Events Research Articles

A Propensity-Score Matched Analysis on Outcomes Using Recombinant Activated Factor VII in Pediatric Cardiac Surgery

To evaluate the effect of recombinant activated factor VII (rFVIIa) administration on outcomes in pediatric cardiac surgery patients with postoperative bleeding. A propensity score-matched retrospective study. Single tertiary medical center. The study comprised 151 patients who received treatment with rFVIIa and were matched with control patients at a 1:2 ratio. None. The primary endpoints were thrombotic events, renal replacement therapy (RRT), and mortality. The secondary endpoints were length of intensive care unit stay and the reexploration rate. Patients in the rFVIIa group showed no significant differences in thrombotic events (odds ratio [OR] 1.03; 95% confidence interval [CI] 0.48-2.21; p = 0.948), mortality (OR 0.94; 95% CI 0.42-2.13; p = 0.891), and RRT (OR 1.38; 95% CI 0.73-2.58; p = 0.319). However, patients in the rFVIIa group experienced a prolonged length of intensive care unit stay (5.65 [3.00-12.28] d v 3.91 [1.83-6.77] d) and an increased reexploration rate (8.2% v 3.1%). High-dose rFVIIa was an independent risk factor of thrombotic events (OR 5.17; 95% CI 1.19-22.49; p = 0.029). This study found that rFVIIa is not associated with increased risks of postoperative thrombotic events, mortality, or RRT in pediatric patients undergoing cardiac surgery. Nevertheless, rFVIIa was associated with longer intensive care unit stay and increased reexploration rate. Furthermore, the risk for thrombotic events may increase with high-dose rFVIIa.

Lower Extremity Free Tissue Transfer in the Setting of Thrombophilia: Analysis of Perioperative Anticoagulation Protocols and Predictors of Flap Failure.

No consensus exists regarding the optimal strategy for perioperative thromboprophylaxis in high-risk microsurgical populations. We present our experience with lower extremity free tissue transfer (FTT) in thrombophilic patients and compare outcomes between non-stratified and risk-stratified anticoagulation protocols. Between January 2013 and December 2017, 57 patients with documented thrombophilia underwent FTT for non-traumatic, lower extremity reconstruction by a single surgeon. Patients were divided into two cohorts based on the introduction of a novel, risk-stratified algorithm for perioperative anticoagulation in July 2015. Demographic data, chemoprophylaxis profiles, flap outcomes, and complications were retrospectively compared across time periods. Fifty-seven free flaps were performed in hypercoagulable patients treated with non-stratified (n = 27) or risk-stratified (n = 30) thromboprophylaxis. Patients in the risk-stratified cohort received intravenous heparin more often than non-stratified controls (73 vs. 15%, p < 0.001). Lower rates of total (3 vs. 19%, p = 0.06) and partial (10 vs. 37%, p = 0.025) flap loss were observed among risk-stratified patients, paralleling a significant reduction in the prevalence of postoperative thrombotic events (1.2 vs. 12.3%, p = 0.004). While therapeutic versus low-dose heparin infusion was associated with improved flap survival following intraoperative microvascular compromise (86 vs. 25%, p = 0.04), salvage rates in the setting of postoperative thrombosis remained 0%, regardless of protocol. On multivariate analysis, recipient-vessel calcification (odds ratio [OR]: 16.7, p = 0.02) and anastomotic revision (OR, 3.3; p = 0.04) were independently associated with total flap failure. Selective therapeutic anticoagulation may improve microsurgical outcomes in high-risk patients with thrombophilia. Our findings highlight the importance of meticulous technique and recipient-vessel selection as critical determinants of flap success in this population.

Association of Perioperative Red Blood Cell Transfusions With Venous Thromboembolism in a North American Registry

Increasing evidence supports the role of red blood cells (RBCs) in physiological hemostasis and pathologic thrombosis. Red blood cells are commonly transfused in the perioperative period; however, their association with postoperative thrombotic events remains unclear. To examine the association between perioperative RBC transfusions and postoperative venous thromboembolism (VTE) within 30 days of surgery. This analysis used prospectively collected registry data from the American College of Surgery National Surgical Quality Improvement Program (ACS-NSQIP) database, a validated registry of 525 teaching and nonteaching hospitals in North America. Participants included patients in the ACS-NSQIP registry who underwent a surgical procedure from January 1 through December 31, 2014. Data were analyzed from July 1, 2016, through March 15, 2018. Risk-adjusted odds ratios (aORs) were estimated using multivariable logistic regression. The primary outcome was the development of postoperative VTE (deep venous thrombosis [DVT] and pulmonary embolism [PE]) within 30 days of surgery that warranted therapeutic intervention; DVT and PE were also examined separately as secondary outcomes. Subgroup analyses were performed by surgical subtypes. Propensity score matching was performed for sensitivity analyses. Of 750 937 patients (56.8% women; median age, 58 years; interquartile range, 44-69 years), 47 410 (6.3%) received at least 1 perioperative RBC transfusion. Postoperative VTE occurred in 6309 patients (0.8%) (DVT in 4336 [0.6%]; PE in 2514 [0.3%]; both DVT and PE in 541 [0.1%]). Perioperative RBC transfusion was associated with higher odds of VTE (aOR, 2.1; 95% CI, 2.0-2.3), DVT (aOR, 2.2; 95% CI, 2.1-2.4), and PE (aOR, 1.9; 95% CI, 1.7-2.1), independent of various putative risk factors. A significant dose-response effect was observed with increased odds of VTE as the number of intraoperative and/or postoperative RBC transfusion events increased (aOR, 2.1 [95% CI, 2.0-2.3] for 1 event; 3.1 [95% CI, 1.7-5.7] for 2 events; and 4.5 [95% CI, 1.0-19.4] for ≥3 events vs no intraoperative or postoperative RBC transfusion; P < .001 for trend). In subgroup analyses, the association between any perioperative RBC transfusion and postoperative VTE remained statistically significant across all surgical subspecialties analyzed. The association between any perioperative RBC transfusion and the development of postoperative VTE also remained robust after 1:1 propensity score matching (47 142 matched pairs; matched OR, 1.9; 95% CI, 1.8-2.1). The results of this study suggest that perioperative RBC transfusions may be significantly associated with the development of new or progressive postoperative VTE, independent of several putative confounders. These findings, if validated, should reinforce the importance of rigorous perioperative management of blood transfusion practices.

Thrombotic and hemorrhagic complications during visceral transplantation: risk factors, and association with intraoperative disseminated intravascular coagulation-like thromboelastographic qualities: a single-center retrospective study.

This study describes the risk of thrombotic and hemorrhagic complications, both intraoperatively, and up to 1 month following visceral transplantation. Data from 48 adult visceral transplants performed between 2010 and 2017 were retrospectively studied [32 multivisceral (MVTx); 10 isolated intestine; six modified-MVTx]. Intraoperatively, intracardiac thrombosis (ICT)/pulmonary embolism (PE) occurred in 25%, 0% and 0% of MVTx, isolated intestine and modified MVTx, respectively, and was associated with 50% (4/8) mortality. Preoperative portal vein thrombosis (PVT) was a significant risk factor for ICT/PE (P = 0.0073). Thromboelastography resembling disseminated intravascular coagulation (DIC) (r time <4 mm combined with fibrinolysis or flat-line) was statistically associated with occurrence of ICT/PE (P < 0.0001). Compared to subgroup without ICT/PE, occurrence of ICT/PE was associated with an increased demand for all blood product components both overall, and each surgical stage. Hyperfibrinolysis (56%) was identified as cause of bleeding in MVTx. Incidence of postoperative thrombotic event at 1 month was 25%, 30% and 17% for MVTx, isolated intestine and modified MVTx, respectively. Incidence of postoperative bleeding complications at 1 month was 11%, 20% and 17% for MVTx, isolated intestine and modified MVTx. In conclusion, MVTx recipients with preoperative PVT are at an increased risk of developing intraoperative life-threatening ICT/PE events associated with DIC-like coagulopathy.

Administration of platelets to ruptured abdominal aortic aneurysm patients before open surgery: a prospective, single-blinded, randomised study.

In patients undergoing open surgery for a ruptured abdominal aortic aneurysm (rAAA), survivors demonstrate a high platelet count, and proactive administration of platelets (and fresh frozen plasma) appears to influence mortality. This trial investigated the effect of platelets administered before transport to surgery. In a prospective study design, patients were randomised to receive platelets (intervention; n = 61) or no platelets (control; n = 61) before transport to vascular surgery from 11 local hospitals. The study was terminated when one of the vascular surgical centres implemented endovascular repair for rAAA patients. Thirty days after surgery, mortality was 36% for patients with intervention vs 31% for controls (P=0·32). Post-operative thrombotic events (14 vs 15; P=0·69), renal failure (11 vs 10; P=0·15) and pulmonary insufficiency (34 vs 39; P=0·15) were similar in the two groups of patients. No adverse reactions to platelet administration were observed. In addition, length of stay in the intensive care unit was unaffected by intervention. For patients planned for open repair of a rAAA, we observed no significant effect of early administration of platelets with regard to post-operative complications and stay in the ICU or in hospital and also no significant effect on mortality.

Clinical Research of Combined Intravenous Administration and Topical Application of Tranexamic Acid to a Surgical Wound During Posterior Lumbar Fusion.

The safety and effectiveness of combined intravenous and topical administration of tranexamic acid (TXA) on the reduction of blood loss in patients undergoing posterior lumbar fusion are not yet clear. The study aimed to investigate the safety and effectiveness of the combined intravenous and topical administration of TXA on the reduction of blood loss in patients undergoing posterior lumbar fusion. One hundred and eighteen patients who underwent double-segment posterior lumbar decompression and fusion from February 2014 to May 2016 in our hospital were retrospectively reviewed. Patients were divided into two groups, the experimental group and the control group. Preoperative demographics, operative parameters, and adverse effect were recorded and compared. Intraoperative blood loss, postoperative 24-hour drainage volume, and blood transfusion ratio and volume were significantly lower in the experimental group than in the control group (P < .01); on postoperative 24 hours and 48 hours, hemoglobin and hematocrit levels were significantly higher in the experimental group than in the control group (P < .01). Prothrombin time and fibrinogen content were not significantly different between the 2 groups. The postoperative length of hospital stay was shorter in the experimental group than in the control group (P < .01). No postoperative thrombotic events were reported in either group. Combined intravenous and topical administration of TXA seems to be effective and safe in reducing allogenic blood transfusion and blood loss in double-segment posterior lumbar decompression and fusion surgery.

Prediction of thromboembolic complications after liver resection for cholangiocarcinoma: is there a place for thromboelastometry?

: Postoperative venous thromboembolism has a poor prognosis in patients with cancer. We aimed to investigate the utility of thromboelastometry in detecting the risk of postoperative venous thromboembolism in patients with cholangiocarcinoma. We prospectively included patients submitted to liver resection for cholangiocarcinoma at our hospital between May 2011 and July 2014. Patients undergoing major hepatectomy for adult living donor transplantation in the same time period served as a control group. Thromboelastometry was performed before anesthesia. Postoperative venous thrombotic events were recorded in the 6 months after surgery. Twenty-seven patients with cholangiocarcinoma and 17 living-donor liver transplantation patients were included. Maximum clot firmness and its derivative parameter G, pointed to hypercoagulability in patients with cholangiocarcinoma, whereas all parameters were within normal ranges in controls. Six postoperative thrombotic events were recorded: four portal vein thrombosis and two deep venous thrombosis, all in patients with cholangiocarcinoma. Patients with cholangiocarcinoma who displayed thrombotic complications showed a nonsignificant trend to more pronounced hypercoagulability compared with those without. The results suggest that first, in patients with cholangiocarcinoma, despite standard thromboprophylaxis, thrombotic events remain a substantial problem, and, second, thromboelastometry may be useful in identifying patients with cholangiocarcinoma at risk of postoperative venous thromboembolism. Large prospective studies are warranted to confirm these results.

Extended use of bemiparin as thromboprophylaxis during bariatric surgery: results of anti-factor Xa activity measurements

BackgroundThe incidence of venous thromboembolism (VTE) in morbidly obese patients after obesity surgery is between .2% and 3.5%. Because there are a lack of prospective studies on the type of drug, the correct dosage, and the optimal duration, there are no specific recommendations found in the guidelines on thrombophylaxis. ObjectivesTo compare the incidence of VTE and hemorrhagic events in bariatric surgical patients receiving bemiparin thromboprophylaxis who have prophylactic and nonprophylactic Anti-factor Xa (AFXa) levels. SettingUniversity General Hospital of Ciudad Real, Spain, public practice. MethodsA cohort study of 122 morbidly obese patients who underwent bariatric surgery. The thromboprophylactic regimen consisted of bemiparin 5000 IU/24 hr for 30 days. AFXa levels were measured on the second and third day postoperation (prophylactic range: .3–.5 IU/mL). Body mass index, co-morbidities, prothrombotic risk factors, and thrombotic and hemorrhagic events were noted. ResultsThe mean body mass index was 48.4 kg/m2. In 50 samples, the level of AFXa was within the prophylactic range; in 71, they were in the subprophylactic range. No VTEs were observed. Major hemorrhagic events were observed in 2.4%. We did not find a significant association between AFXa and thromboembolic and hemorrhagic events. There is a significant negative correlation between the level of AFXa and body mass index. ConclusionA regimen of 5000 IU/24 hr of bemiparin for 30 days after obesity surgery appears to prevent VTE without increasing the risk of a major hemorrhage. The level of AFXa is not associated with postoperative thrombotic or hemorrhagic events occurring after bariatric surgery.

Elevated preoperative von Willebrand factor is associated with perioperative thrombosis in infants and neonates with congenital heart disease

Essentials Perioperative thrombosis is a major cause of morbidity and mortality in congenital heart disease. Neonates and infants undergoing repair of congenital heart lesions were prospectively followed. Elevated von Willebrand factor (VWF) to ADAMTS-13 activity ratios typified the postoperative period. Thrombosis was associated with preoperative VWF activity and cryoprecipitate transfusion SUMMARY: Background The surgical repair of congenital heart malformations is frequently complicated by perioperative thrombosis of unclear etiology. An imbalance between von Willebrand factor (VWF) and ADAMTS-13 is an emerging variable in thrombosis. Objectives To describe perioperative changes to VWF, ADAMTS-13 and NETosis, and evaluate clinical and biochemical associations with postoperative thrombosis. Methods Neonates and infants undergoing palliation or definitive surgical repair of congenital heart malformations were recruited (n=133). Preoperative and postoperative plasma levels of VWF, ADAMTS-13 and markers of NETosis were determined. Patients were followed for up to 30days for the occurrence of thrombosis. Univariate and multivariate logistic regression analyses were conducted to identify variables associated with thrombosis. Results We identified significant postoperative increases in VWF activity, VWF level, DNA-histone complexes and cell-free DNA with an overall decrease in ADAMTS-13 activity. Patients experiencing postoperative thrombotic events (9%) were characterized by surgery performed at a lower intraoperative temperature, higher preoperative lactic acid levels, and higher preoperative VWF activity and level. A multivariate logistic regression model identified preoperative VWF activity (odds ratio (OR)8.39 per IUmL-1 , 95% confidence interval [CI]1.73-40.55) and transfusion of cryoprecipitate (OR1.10 per mLkg-1 , 95%CI1.03-1.17) as being associated with thrombosis. Conclusions Pediatric patients undergoing surgical repair of congenital heart malformations are exposed to high levels of VWF with diminished or minimal change to ADAMTS-13 in the immediate postoperative period. Elevated preoperative VWF activity is associated with postoperative thrombosis in pediatric congenital heart disease.

PO-62 - Remote ischemic preconditioning in head and neck cancer reconstruction – a randomized controlled trial

In reconstructive head and neck cancer surgery, tissue flaps are transferred to the surgical defect and revascularized by anastomosis of small vessels. Cancer patients are in a hypercoagulable state with high risk of peri- and postoperative thrombotic events. Thrombosis to the tissue flap anastomoses or microcirculation is the main reason for total flap necrosis with potential fatal consequences for the patient. Remote ischemic preconditioning (RIPC), where brief cycles of upper extremity ischemia are induced with an inflatable tourniquet, triggers a global protection of tissues subjected to ischemia-reperfusion injury. RIPC has also been shown to impact the coagulation system. The aim of the trial is to investigate, if RIPC attenuates platelet aggregation during reconstructive head and neck cancer surgery. Sixty patients with head and neck cancer will be included in the trial. The subjects will be randomized to RIPC or sham during surgery. RIPC is administered by four 5-minute cycles of upper extremity ischemia, each separated by five minutes of reperfusion. Blood samples will be drawn preoperatively, before RIPC/sham, 3 hours after RIPC/ sham, 6 hours after RIPC/sham, and on the first postoperative day. Platelet aggregation will be measured with the Multiplate® analyzer using collagen, ADP and TRAP as agonists. Furthermore, platelet count, mean platelet volume, immature platelet fraction, and von Willebrand factor antigen are determined. The trial is ongoing. Preliminary results will be presented at ICTHIC 2016. If RIPC proves to attenuate platelet aggregation, it could become a novel antithrombotic treatment in oncologic reconstructive surgery. Hence, morbidity and mortality related to surgery is reduced, and adjuvant oncologic therapy can be initiated in timely fashion.

Lower Extremity Flap Salvage in Thrombophilic Patients: Managing Expectations in the Setting of Microvascular Thrombosis.

Background Undiagnosed thrombophilia is a risk factor for flap failure; however, its prevalence in patients undergoing microsurgical reconstruction is unknown. We present our experience with free tissue transfer (FTT) in a high-risk population of lower extremity patients with documented thrombophilia, identified through preoperative screening. Methods Between January 2012 and April 2014, 41 patients underwent 43 free flaps for nontraumatic, lower extremity reconstruction by a single surgeon. Patients were preoperatively screened for thrombophilia using historical information and standardized laboratory testing. Demographic data, perioperative management, outcomes, and salvage rates for thrombophilic and nonthrombophilic cohorts were compared. Results Routine preoperative screening identified 52 thrombophilic traits among 25 patients in this series (61%). The most common traits were the plasminogen activator inhibitor-1 4G/5G variant (n = 12) and the methylenetetrahydrofolate reductase A1298C (n = 10) and C677T (n = 9) polymorphisms. While success rates were similar between thrombophilic and nonthrombophilic patients (84 vs. 94%; p = 0.15), thrombotic complications (25 vs. 14%; p = 0.09) and flap failure following postoperative thrombosis (100 vs. 33%; p = 0.05) appeared to be more common in patients with thrombophilia. On average, microvascular complications manifested later in the setting of thrombophilia (mean 4.8 days vs. 18 hours; p = 0.20) and were associated with a worse overall prognosis (salvage rate, 0 vs. 67%; p = 0.05). Conclusions Despite high success rates, thrombophilia appears to increase the risk of nonsalvageability following lower extremity FTT. This information should be used to help counsel patients regarding the risks and benefits of microsurgical reconstruction, as salvage rates following postoperative thrombotic events approach 0% in the presence of thrombophilia.

Pediatric En Bloc Kidney Transplants: Clinical and Immediate Postoperative US Factors Associated with Vascular Thrombosis.

Purpose To evaluate clinical and immediate postoperative ultrasonographic (US) risk factors associated with vascular thrombosis of pediatric en bloc kidney grafts. Materials and Methods This institutional review board-approved HIPAA-compliant retrospective study consisted of 195 recipients of pediatric en bloc kidney grafts throughout a 10-year period. The average recipient and donor age was 45 years (range, 7-74 years) and 9 months (range, 0-84 months), respectively. Clinical factors and immediate postoperative US findings were assessed. Categorical variables were evaluated by using the Fisher exact test and linear models with generalized estimating equations. Results Seventeen patients (23 kidneys) experienced thrombotic events. In six patients (eight kidneys), thrombosis occurred intraoperatively. The remaining 11 patients (15 kidneys) received a diagnosis of thrombosis on postoperative days 1-13. Recipients more than 40 years old had a higher incidence of arterial thrombosis than did younger recipients (eight of 62 vs three of 133, respectively; P < .01). Recipients were more likely to develop thrombosis with donor weight less than 5 kg (10 of 52 vs seven of 140 with donor weight of ≥ 5 kg; P < .01), with intraoperative perfusional concern (10 of 21 vs seven of 174 without; P < .01), or with right-sided allograft placement (10 of 64 vs seven of 131 left sided; P = .03). At US of the 15 postoperative thrombotic events, the incidence of thrombosis was greater when donor arterial velocity was less than 100 cm/sec (seven of 56 vs four of 126 with velocity ≥ 100 cm/sec; P = .04). An intrarenal arterial resistive index of less than 0.6 was associated with higher incidence of arterial thrombosis (nine of 123 vs zero of 217, respectively; P = .01). A resistive index greater than 0.8 was associated with a higher incidence of venous thrombosis (four of 13 vs one of 217, respectively; P = .04). Conclusion Clinical factors and immediate US findings can help stratify patients receiving pediatric en bloc kidneys into risk categories for vascular thrombosis that, if proven in prospective studies, could affect immediate postoperative treatment. (©) RSNA, 2015.

Role of Extended Thromboprophylaxis after Abdominal and Pelvic Surgery in Cancer Patients: A Systematic Review and Meta-Analysis

IntroductionAbdominal or pelvic surgery for cancer increases the risk of postoperative venous thromboembolism (VTE) by 2- to 3-fold. The use of low-molecular weight heparin (LMWH) to prevent post-operative thrombotic events is recommended in high VTE-risk patients; however, the role of extended thromboprophylaxis in this setting is controversial. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) and prospective observational studies to determine the effect of extended LMWH thromboprophylaxis on all VTE, deep vein thrombosis (DVT), pulmonary embolism (PE), major bleeding, and all-cause mortality after abdominal or pelvic surgery for cancer.MethodsWe searched MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials, conference abstracts, and trial registries with no language restriction. Studies were included if they compared extended duration (i.e., administration of prophylactic doses of LMWH for more than 2 weeks, up to 6 weeks) versus conventional duration of thromboprophylaxis (i.e., administration of LMWH for two weeks or less) after cancer surgery. Two reviewers independently performed study selection, data extraction, and quality assessment. Studies were evaluated according to a priori inclusion criteria and critically appraised using the Newcastle-Ottawa Quality Assessment Scale (NOQA). Pooled relative risk was estimated using a random effects model.ResultsThree RCTs and 4 observational studies were included, comprising 4807 adult patients who underwent open or laparoscopic abdominal or pelvic surgery for gastrointestinal, gynecological or urological cancers. The 3 RCTs employed screening for asymptomatic DVT using bilateral lower limb compression ultrasound or venography after 4 weeks of surgery. Most of studies were of good quality (NOQA higher or equal to 6). The extended thromboprophylaxis regimen was associated with a significantly reduced incidence of all VTE (2.6% [59/2292] vs 5.6% [124/2209]; RR=0.44 [95% CI 0.28-0.70]) and proximal DVT (1.4% [14/966] vs 2.8% [24/862]; RR=0.33 [95% CI 0.15-0.73]). No data were available for symptomatic DVT. There was no statistically significant difference in the incidence of symptomatic PE between the two groups (0.8% [8/966] vs 1.3% [11/862]; RR= 0.56 [95% CI 0.23-1.40]). We found no significant difference in major bleeding at 1.8% (14/787) in the extended thromboprophylaxis group vs 1.0% (7/713) in the short thromboprophylaxis group (RR=1.19 [95% CI 0.47-2.97]). There was no significant difference in all-cause mortality at 3 months (4.2% [30/720] vs 3.6% [23/643], respectively; RR= 0.79 [95% CI 0.47-1.33]). There was minor heterogeneity between the studies in all extracted outcomes.ConclusionExtended thromboprophylaxis with LMWH after abdominal or pelvic surgery for cancer significantly decreased the incidence of all VTE and proximal DVT, but had no impact on symptomatic PE, major bleeding or 3-month mortality. [Display omitted] DisclosuresLee:Pfizer: Consultancy, Honoraria; LEO Pharma: Consultancy, Honoraria; BMS: Research Funding; Bayer: Consultancy. Wu:Leo Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

Management of perioperative microvascular thrombotic complications – The use of multiagent anticoagulation algorithm in 395 consecutive free flaps

Thrombotic complications remain a major barrier to successful microsurgical reconstruction, but their effective management remains controversial. A retrospective review of 395 consecutive microvascular transfers was performed with the focus on treatment of thrombotic complications utilizing an algorithm, which employed multiagent anticoagulation. Three-hundred-ninety-five free flaps were performed in 255 patients for breast (n = 316), head and neck (n = 57), extremity (n = 16), trunk (n = 3), and pelvis (n = 3) defects that were oncologic in 95.2% and irradiated in 33.4% of cases. Patients with a hypercoagulable history (8 of 9) and intraoperative thrombosis (16 of 16) were anticoagulated without developing postoperative thrombotic events. The hematoma exploration rate among the patients anticoagulated during the initial free flap procedure was 27%. Twenty four (9.4%) patient were returned to the operating room postoperatively for threatened free flaps: 6 had non-microvascular issues and 18 (7.1%) patients underwent microsurgical explorations. Fourteen (5.5%) patients had 15 postoperative free flap thrombotic events in 14 free flaps, of which 12 flaps were successfully salvaged with a combination of flap intra-arterial (n = 15), subcutaneous/intramuscular (n = 6), and intravenous (n = 3) tissue plasminogen activator (tPA), microvascular explorations (n = 20), and therapeutic multiagent anticoagulation/antiplatelet therapy (n = 17); none had a hematoma of the reconstructed site. Two free flaps were lost to arterial thrombosis, with an overall microvascular salvage rate of 89% and a free flap success rate of 99.5%. Thrombophilia uncovered by microvascular procedures can be effectively treated with anticoagulation upon discovery and prevent postoperative free flap thrombotic events. High free flap salvage can be achieved with the early intervention combined with thrombolysis and multiagent anticoagulation and antiplatelet therapy.

A Prospective, Active-control, Non-inferiority Study of the Effectiveness of Low Molecular Weight Heparin in the Prophylaxis of Postoperative Thrombotic Events in Patients Undergoing Spinal Surgery

Background: The Incidence of verified thrombotic events after elective spine surgery is 18%. Low-Molecular- Weight-Heparin (LMWH) is routinely given on the day before surgery. A postoperative start of the thrombotic prophylaxis could be an advantage in cases with opening of the spinal canal and for preventing epidural bleeding. Patient and methods: This active-controlled non-inferiority trial compared the effectiveness and safety of LMWH started pre- or postoperatively in patients undergoing spinal surgery. We analysed the incidence of clinically symptomatic venous thromboembolism. Results: A total number of 241 patients were followed over 14.6 patient-years. The incidence risk of fatal thromboembolisms was 0.011 (95%CI 0.0003 to 0.06) for the group with preoperative treatment and 0.01 (95% CI 0.0002 to 0.04) for the postoperatively treated group. The crude risk ratio was 1.65 (95%CI 0.10 to 26.03). There was no statistically significant difference in risk across groups (p=0.72). The Poisson regression model including follow-up time showed an incidence rate ratio of 0.67 (95% 0.04 to 10.74, p=0.779). There was no increased risk for complications (p=0.211). Conclusion: This study demonstrates that the postoperative start of LMWH in the prophylaxis of thrombotic events in patients undergoing spinal surgery does not affect safety or the incidence of complications.

Intraoperative perfusion management impacts postoperative outcomes: An analysis of 682 autologous breast reconstruction patients

Anesthetic management remains an understudied aspect of free autologous breast reconstruction. This study aims to critically examine intraoperative anesthetic management as it relates to free flap perfusion and its effect on major complications. A retrospective cohort study was performed examining all abdominally based free autologous breast reconstructions from 2005 to 2011 at a single institution. Analysis focused on perioperative care and specifically fluid administration, urine output (UOP), vasopressor administration, and case duration. Outcomes included major intraoperative and postoperative complications. A post-hoc analysis was performed to determine anesthetic factors associated with thrombotic events. Overall, 682 patients (1033 flaps) were included. Patients with low UOP had lower rates of intraoperative fluid infusion rates/kg (p=0.0001), Estimated Blood Loss (EBL) (p=0.006) and pressor administration (p=0.03), but no significant differences were noted in intraoperative thrombotic events according to UOP. However, the below normal UOP cohort demonstrated a significant increased rate of delayed postoperative thromboses (p=0.03). A post hoc analysis of postoperative thrombotic events revealed that low rates of fluid resuscitation (OR=3.01, p=0.04) and low intraoperative UOP (OR=3.67, p=0.04) were independently associated with delayed thrombosis. A sub-analysis demonstrated that patients with ≥2 comorbidities and below normal UOP were at particular risk (any delayed thrombotic event OR=4.3, p=0.03; any delayed venous thrombosis OR=9.1, p=0.03). This study demonstrates that intraoperative fluid under-resuscitation may place patients at increased risk for postoperative flap thrombosis, and low UOP is an important metric whereby intraoperative resuscitation should be gauged. Patients with comorbid conditions and below normal intraoperative UOP should be monitored particularly closely for delayed thrombotic events. Prognostic/risk category, level II.

Hemorrhagic shock occurring due to a concealed hematoma after insertion of a subclavian venous catheter in a patient undergoing anticoagulation therapy: a case report.

A 74-year-old man who had been receiving warfarin for atrial fibrillation, underwent emergency thrombectomy. A central venous catheter (CVC) was inserted via the left subclavian vein, and heparin was administered to prevent preoperative and postoperative thrombotic events. After an uneventful thrombectomy, the patient was transferred to the intensive care unit (ICU). On the second postoperative day, the patient developed syncope and his blood pressure and oxygen saturation decreased. A computed tomography (CT) revealed a huge hematoma under the pectoralis major muscle. The patient was then treated with continuous renal replacement therapy and mechanical ventilation for multiorgan dysfunction syndrome, which developed due to hemorrhagic shock in the ICU. These findings suggest that when a CVC is inserted in patients requiring anticoagulant therapy, the possible risk of excessive bleeding must be carefully considered. Further, choosing a proper insertion site and performing an ultrasound-guided aspiration may be helpful in preventing these complications.

Endovascular treatment of iliofemoral chronic post-thrombotic venous flow obstruction.

Patients with deep vein thrombosis affecting the iliac and vena cava veins develop a more severe post-thrombotic syndrome than those with femoropopliteal disease. It has been traditionally treated only with medical therapy. During the last decade, endovascular repair has become the treatment of choice. The aim of this study is to report our midterm results using this technique. From 2009 to 2012, 41 limbs in 36 patients with post-thrombotic chronic flow obstruction of iliofemoral vein secondary to stenotic or occlusive lesions and with a clinical CEAP class 3 or higher or venous pain underwent percutaneous treatment. Stent-related outcome (patency and thrombotic events), clinical outcome (improvement of revised Venous Clinical Severity Score [VCSS] and Villalta score) were evaluated after intervention. The procedure was successful in 39 limbs (95%) withno mortality and low morbidity. Thrombotic events occurred in nine limbs (23%) during the follow-up period. At33 months, primary, assisted-primary, and secondary cumulative patency rates were 74%, 87%, and 89%, respectively. The main risk factor associated with stent occlusion was the severity of thrombotic disease. All postoperative thrombotic events occurred in occluded veins; no previously stenotic veins presented any complication (P= .04). Presence of thrombophilia, stent brand, and stent extension into the common femoral vein were not significantly associated with stent thrombosis. After surgery, the mean revised VCSS and Villalta scores improved substantially (P< .0001). The cumulative rate of revised VCSS improvement was 89% at 33months. Clinical improvement was observed despite deep venous system reflux remaining uncorrected. Percutaneous treatment of post-thrombotic venous flow obstruction is an excellent therapeutic option withlow morbidity and no mortality. It can be performed with high midterm patency rates and midterm clinical improvement.

Serum Antibodies to the Heparin/Platelet Factor 4 Complex Are an Independent Predictor of Thrombotic Complications Following Pediatric Fontan Surgery

Antibodies to the heparin/platelet factor 4 complex (heparin/PF4) are linked to the pathogenesis of heparin-induced thrombocytopenia (HIT) and to the thrombotic complications. We investigated thrombotic events during early follow-up in a pediatric cardiac surgical population to ascertain whether there is a relation between heparin/PF4 antibody concentration and post-surgical thrombotic complications. One hundred and five consecutive pediatric patients treated by Fontan surgery were studied. The presence of serum heparin/PF4 immunoglobulins IgG, IgA, and IgM (collectively termed HIT antibodies) were measured in preoperative and postoperative blood samples by enzyme-linked immunosorbent assay. On day six after Fontan surgery, HIT-related thromboses was identified in total of 11 patients (10.5%). HIT antibodies were detected in 34 of 105 patients (32.4%). The post-surgical nadir platelet count was significantly lower in patients who developed antibodies (p < 0.001). We found the odds ratio (OR) for this composite endpoint was 4.06 (p < 0.001). Seropositive status for heparin/PF4 antibodies was an independent predictor of thrombotic events (OR 2.28; p < 0.001). Quintile analysis revealed that the median nadir platelet value was significantly lower in patients with higher HIT antibody titers. Patients in the highest quintile of HIT antibody titer all experienced thrombotic events, while only two thrombotic events occurred in patients in the lowest quintile (p < 0.001). Heparin-induced thrombocytopenia is a rare occurrence in pediatric cardiac surgical patients. Patients who develop antibodies to the heparin/PF4 complex have a significantly higher rate of postoperative thrombotic events than patients who lack these antibodies. Within the seropositive group, the risk of developing thrombosis increased with the plasma antibody concentration.

Hemostatic Outcomes of Hip and Knee Joint Replacement Surgery in Von Willebrand Disease (VWD) Patients: A Single Center Study

Abstract▪2279▪This icon denotes a clinically relevant abstractSurgery for patients with von Willebrand disease (VWD) is increasingly common, however there is a paucity of data on hemostatic outcomes for VWD patients undergoing joint replacement surgery when compared to patients without bleeding disorders. The aim of this study was to evaluate hemostatic prophylaxis and outcomes in VWD patients who underwent hip or knee joint replacement, with comparison to matched case control patients. Methods: We retrospectively reviewed medical records of VWD patients who underwent total hip (THA) or total knee (TKA) arthroplasty between February 1993 and January 2011 at Mayo Clinic Rochester. Outcomes for each VWD patient were compared with two case controls matched for age, gender, surgeon and surgery. For VWD patients the hemostatic prophylaxis regimen during and following surgical procedures was evaluated including results of serial monitoring of plasma levels of VWF:RCo, VWF:Ag and FVIII:C. We compared VWD and control cases for bleeding complications (major and minor), transfusion requirements, DVT (deep vein thrombosis) prophylaxis and occurrence, duration of hospitalization, and other complications. Results: Twelve VWD patients (7 female) underwent 12 TKA and 7 THA surgeries; the median age was 62 (range 42–76) years. Seven had Type 1 VWD, one had Type 3 and four had Types 2A, 2B or 2M VWD. The 19 surgical episodes were matched to 38 control surgeries. Indications for arthroplasties were mainly degenerative joint disease in both subject groups. The median BMI was 30 (range 21–45) in the VWD patients and 31.9 (20–53) in controls. Three patients with mild Type 1 VWD received during 5 surgeries only one preoperative dose of DDAVP (desmopressin 0.3μg/kg body weight). Infusions of VWF/FVIII concentrates (Humate-P or occasionally Koate-DVI) were prescribed for twelve procedures, with median preoperative dose 52 IU/kg (range 19–71). Postoperative maintenance doses were infused once or twice daily usually for up to 7 days (more than 7 days only for one Type 3 and one Type 2A VWD patient), with median ranges 22 to 38 IU/kg, and highest dose 90 IU/kg and lowest dose 11 IU/kg (typically when treatment was administrated twice daily). These substantial ranges may be explained by dose adjustments based on monitoring postoperative plasma levels of VWF:RCo and FVIII:C. The median number of infusions per procedure was 5.5 (range 1–13). One hour after the preoperative dose the median of all factors was more than 110 IU/dL, specifically VWF:RCo 154 UI/dL (range 72–277), VWF:Ag 178 IU/dL (range 101–307), and FVIII:C 114 IU/dL (range 64–290). The lowest factor levels measured during daily postoperative follow-up are represented in Figure 1. Assessment of red blood cell transfusion requirements showed no difference between baseline and D1 blood hemoglobin levels for VWD and control groups (decline of 3.0 g/dL). During follow-up, hemoglobin levels and total blood losses were also not different between both groups. However, the number of patients transfused was twice as high for the VWD group (63% vs 32% for controls, respectively), and the mean number of RBC units transfused was higher in VWD patients than in controls (1.5 vs. 0.6 units, respectively). DVT prophylaxis (low molecular weight heparin (LMWH) injections or warfarin), was administrated to 58% of VWD patients vs. 97% of controls. No postoperative thrombotic events were identified in either group. Finally, the median duration of hospitalization for VWD patients and controls was not different: 5 days (range 3–13) and 5 days (range 3–7) respectively. Conclusions: Few data are available in published literature analyzing treatment regimens and hemostatic outcomes for patients with VWD undergoing THA or TKA, a relatively common treatment for advanced degenerative joint disease. This is the first large retrospective study which reports the effectiveness of prophylactic regimens specifically in joint replacement for patients with VWD. Our results support that, as recommended in the 2008 NHLBI/NIH treatment guidelines, monitoring of plasma VWF and FVIII levels at least once daily allows for efficient and relatively low dose maintenance administration. Further, our study helps identify an adequate duration of treatment for these major surgeries, without substantively increased blood loss for VWD patients compared with controls. Disclosures:No relevant conflicts of interest to declare.