Prophylaxis with enoxaparin for prevention of venous thromboembolism after lung transplantation: a retrospective study

Venous thromboembolism following lung transplantation

Lung transplantation (LT) is currently a surgical therapy option for end-stage lung disease. Venous thromboembolism (VTE), which can occur after LT, is associated with significant morbidity and mortality. Because of improved outcomes, increasing numbers of patients are receiving LT as treatment. Patients on the waitlist for LT tend to be older with weakness and frailty in addition to pulmonary symptoms. These factors contribute to a heightened risk of postoperative VTE. Furthermore, patients who clinically deteriorate while on the waitlist may require extra corporeal membrane oxygenation as a bridge to LT. Bleeding and thromboembolism are common in these patients. Pulmonary embolism (PE) in a freshly transplanted lung can have significant effects leading to morbidity and mortality. PE typically leads to impairment of gas exchange and right ventricular strain. In LT, PE can affect healing of bronchial anastomosis and may even contribute to the development of chronic allograft lung dysfunction. This article discussed the incidence, clinical features and diagnosis of VTE after LT. Furthermore, the treatment modalities, complications, and outcomes of VTE were reviewed.

Pulmonary Embolism as a Cause of Death in Lung Transplant Recipients: Data From a Nationwide Registry

Pulmonary embolism (PE) is a leading cause of mortality in lung transplant recipients, with early cases associated with particularly poor outcomes. Identified risk factors include elevated BMI, renal dysfunction, ABO mismatch, donor malignancy, and specific immunosuppressive agents. Tailored risk assessments and targeted interventions are essential to mitigating PE-related mortality.

Pulmonary Embolism Following Lung Transplantation: Prevention and Management

Thromboembolic events are the third leading cardiovascular diagnosis following stroke and myocardial infarction. In the United States, 300,000 to 600,000 people per year are diagnosed with venous thromboembolism, either deep venous thrombosis or pulmonary embolism (PE). Of those patients, thousands die from PE despite heightened vigilance and improved therapies. Lung transplant recipients are at increased risk of developing PE due to multiple risk factors unique to this population. Additionally, the transplant recipients are more susceptible to morbid complications from PE. As a result, prevention, timely recognition, and intervention of PE in the lung transplant population are of the utmost importance.

Limited Effect of Prevention Strategies on Incidence of Clinically Detectable Venous Thromboembolism After Lung Transplantation

BACKGROUND

Thromboembolic complications are common post-lung transplant, leading to significant morbidity. We instituted multiple interventions because of an observed 36.8% incidence of venous thromboembolism (VTE) (Incidence rate (IR) 5.74/1000 pt days) in our recipients.

METHODS

Our initiative commenced January 2015 with enoxaparin initiation within 6-8 hours of intensive care unit arrival and continuation for 4-6 weeks. We evaluated the IR of VTE in lung transplant recipients within 90 days of transplant. In 2017, the protocol was modified to extend the time to initiation of prophylaxis to within 72 hours of ICU arrival. In 2019, we further amended our intraoperative vascular access strategy.

RESULTS

Eighteen of 26 lung transplant recipients (LTR) met inclusion criteria in the 2015 cohort. Six of 18 (33.3%) developed VTE, 50% of which were upper extremity (UE), line associated. Fifty two of 75 LTR were eligible for enoxaparin prophylaxis in the 2017 cohort. Fifteen of 52 subjects (28.8%) developed VTE, 77.8% of which were UE and line associated. Despite improved adherence in 2017, there was little change in VTE IR (3.90/1000 pt days compared with 3.85/1000 pt days). Twenty six of 43 LTR met protocol inclusion criteria in the 2019 cohort. Ten subjects (38.5%) developed VTE, 67% of which were UE and line associated (IR 5.18/1000 pt days).

CONCLUSION

Our prospective study found that LTR remain at high risk for VTE despite aggressive prophylaxis with 4-6 weeks of enoxaparin and adjustment of vascular access approach. Alternative interventions should be investigated to minimize VTE development in this vulnerable population.

Heparin-Free Lung Transplantation on Venovenous Extracorporeal Membrane Oxygenation Bridge

Extracorporeal membrane oxygenation (ECMO) bridge to lung transplantation (LuTX) exposes the patients to a high risk of perioperative bleeding secondary to systemic anticoagulation and coagulation factors deficiency. With this case series, we propose innovative "no-heparin" management of ECMO-bridge support during LuTX, based upon 1) control heparin resistance with antithrombin III in the preoperative period; 2) relying upon a fully functional, brand new heparinized ECMO circuit; 3) completely avoiding perioperative heparin; 4) hampering fibrinolysis with tranexamic acid; and 5) limiting venoarterial (VA) ECMO escalation, and the following need for full anticoagulation. Following the application of this new approach, we carried out three challenging clinical cases of bilateral ECMO-bridged LuTX effectively, with limited intraoperative blood requirement and no major postoperative bleeding or thromboembolic events. Of note, two of them had an extremely high risk for hemorrhage due to complete right lung anatomic derangement in case number 2 and surgical adhesion following first LuTX in case number 3, while for the case number 1, no blood products were administered during surgery. Despite the limited patient population, such an approach relies on a strong rationale and may be beneficial for managing ECMO bridging to LuTX. Prospective studies are necessary to confirm the validity of our strategy.

Venous thromboembolism in lung transplant recipients real world experience from a high volume center

BACKGROUND

Venous thromboembolism (VTE) post lung transplantation is common and has been associated with worse post transplant survival. We report a comprehensive single center review of VTE incidence in the first post transplant year, investigate modifiable risk factors and assess impact on short term outcomes.

METHODS

Retrospective review of all lung transplant recipients between August 2016 to 2018 at Temple University Hospital. Patients were followed for 1 year post transplant. All patients were screened for deep venous thrombosis (DVT) within the first 2 weeks with a venous duplex study. Pre transplant, intra operative, post operative variables, and peri-operative practice patterns were compared between VTE positive and VTE negative groups. Logistic regression modeling was used to identify risk factors for early VTE (VTE within 30 days after transplant).

RESULTS

A total of 235 patients were included in the study, 58 patients (24.7%) developed a VTE in the first post transplant year. Median time to diagnosis was 17 days. Of the patients with VTE, 76% had an isolated DVT, 13.5 % had an isolated pulmonary embolism (PE), and 10.3% had concomitant DVT and PE. In a multivariate logistic regression model, cardiopulmonary bypass (CPB) (OR 1.93 p = 0.015) and interruption of VTE prophylaxis (OR 4.42 p < 0.0001) were predictive of early VTE.

CONCLUSION

VTE post lung transplant is common despite the use of prophylactic anticoagulation. CPB use and interruption of DVT prophylaxis are risk factors for early post transplant VTE. Measures to ensure consistent and uninterrupted prophylaxis may help decrease VTE incidence after lung transplantation.

Venous thromboembolism in solid-organ transplant recipients: Findings from the RIETE registry

BACKGROUND

Venous thromboembolism (VTE) represents a relevant cause of morbidity in patients with solid-organ transplant (SOT), but there are scarce data on the management and outcomes in these patients.

METHODS

RIETE is a worldwide, ongoing observational registry of patients with objectively confirmed, acute VTE. We used the RIETE database to compare the clinical characteristics, treatment and outcomes in SOT recipients vs. non-recipients.

RESULTS

From January 2001 to December 2019, 83,210 patients were enrolled in RIETE. Of these, 329 (0.4%) were SOT recipients: in the kidney 221, liver 41, lung 28 and heart 25. Median duration of anticoagulation was similar in SOT recipients and non-recipients (174 vs. 182 days). During anticoagulation, 1180 patients developed deep vein thrombosis (DVT) recurrences, 1028 pulmonary embolism (PE) recurrences, 2392 had major bleeding, 3119 non-major bleeding and 8157 died. SOT recipients had a higher rate of major bleeding (hazard ratio [HR]: 2.55; 95% CI: 1.62-3.84) and clinically relevant non-major bleeding (HR: 1.94; 95% CI: 1.23-2.93) than non-recipients, with no differences in the rates of DVT recurrences (HR: 0.96; 95% CI: 0.30-2.32), PE recurrences (HR: 1.11; 95% CI: 0.35-2.67) or death (HR: 0.98; 95% CI: 0.67-1.40). On multivariable analysis, only liver transplant recipients were at an increased risk for major bleeding compared to non-recipients (adjusted HR: 3.17; 95% CI: 1.02-9.87).

CONCLUSIONS

Treatment of VTE in SOT recipients is associated with an increased risk of bleeding compared to non-recipients. This is mainly due to the influence of liver transplant recipients. In non-liver SOT recipients, the risk for bleeding was similar to that in non-recipients.

Characteristics and Outcomes Among Patients With Early Venous Thromboembolic Events After Lung Transplant

BACKGROUND

Despite several previous studies reporting a high frequency of venous thromboembolism (VTE) after lung transplant (LT), few actionable risk factors have been identified. There are limited data regarding the practice patterns of anticoagulation use among patients with LT.

METHODS

All adult patients with single or bilateral LT between 2012 and 2016 were included (n = 324; mean age, 56.3 ± 13.3 years; male, 61.1%). Demographic, clinical, and laboratory variables before and after LT were recorded. Follow-up data included survival up to 3 years post-transplant. Development of VTE during the first 30 days after LT was the primary outcome variable.

RESULTS

The overall incidence of VTE during the first 30 days after LT was 29.9% (n = 97), among which the majority were upper extremity thromboses. Female sex, personal history of VTE, hospitalization at the time of transplant, and use of 3 or more central venous catheters during index hospitalization were independently associated with VTE. The use of anticoagulants was independently associated with a reduced risk of VTE. Despite increased morbidity, the development of VTE was not associated with worse post-transplant survival.

CONCLUSIONS

A significant proportion of patients develop early VTE after LT. Limiting the number of central catheters to < 3 during the post-transplant period, along with the early institution of thromboprophylaxis, may lower the risk of VTE.