Cytomegalovirus-associated venous thromboembolism in renal transplant recipients: a report of 7 cases

Prevalence, risk, and outcomes of venous thromboembolic events in kidney transplant recipients: a nested case-control study

INTRODUCTION

Thromboembolism is more common in kidney transplant recipients (KTRs) than in the general population. Studies evaluating arterial and venous thromboembolism (VTE) in KTRs are scarce and the magnitude and risk factors are mostly undefined.

METHODS

A nested control study was conducted from January 1, 2007, to December 31, 2019. Adult KTRs who were detected to have VTE events during this period were included. The primary outcome was to assess the prevalence of VTE in this population. Secondary outcomes were the assessment of the time to occurrence of the thromboembolic events after transplantation and assessing the risk factors and patient survival. For each subject studied, 4 controls were matched from the data set.

RESULTS

Amongst 2158 patients, 97 (4.5%) were found to have VTE. The median follow-up time was 3.9 years (6-156 months). A total of 101 VTE events were recorded. The most common site of VTE was the lower limb deep vein thrombosis in 79 patients (0.03%)).In multivariate Cox regression analysis, serum creatinine of more than 3 mg/dl [HR 1.30, 95% CI (1.03-1.38)] was independently associated with increased VTE risk. Patients who developed a VTE had higher mortality as compared to patients who did not develop VTE. No increased risk of graft failure was found in VTE patients.

CONCLUSION

This study suggests that kidney transplantation surgery is a moderate risk factor for VTE, and VTE is associated with higher morbidity and mortality. However, prospective studies are needed to establish a definite role of VTE in outcomes in KTRs.

Pathophysiological Changes in the Hemostatic System and Antithrombotic Management in Kidney Transplant Recipients

Nowadays, the main cause for early graft loss is renal graft thrombosis because kidney transplant outcomes have improved drastically owing to advances in immunological techniques and immunosuppression. However, data regarding the efficacy of antithrombotic therapy in the prevention of renal graft thrombosis are scarce. Adequate antithrombotic management requires a good understanding of the pathophysiological changes in the hemostatic system in patients with end-stage kidney disease (ESKD). Specifically, ESKD and dialysis disrupt the fine balance between pro- and anticoagulation in the body, and further changes in the hemostatic system occur during kidney transplantation. Consequently, kidney transplant recipients paradoxically are at risk for both thrombosis and bleeding. This overview focuses on the pathophysiological changes in hemostasis in ESKD and kidney transplantation and provides a comprehensive summary of the current evidence for antithrombotic management in (adult) kidney transplant recipients.

Postoperative statin therapy is not associated with reduced incidence of venous thromboembolic events following kidney transplantation

BACKGROUND

The pleiotropic effects of statin therapy on inflammation and coagulation may reduce the risk of venous thromboembolism. This study evaluated whether statin therapy is associated with decreased venous thromboembolic (VTE) events following kidney transplantation.

METHODS

We performed a retrospective analysis of all primary kidney transplants performed between January 2014 and December 2019 at Mayo Clinic Arizona. Patients were divided into two groups depending on sustained statin therapy during the first year following transplantation. Recipient and donor clinical and demographic data were collected. The primary outcome was admission for symptomatic VTE events (deep vein thrombosis [DVT] or pulmonary embolism [PE]).

RESULTS

Sustained statin therapy in the first year following transplant was observed in 16.1% (n = 223) of 1384 kidney transplants. The overall incidence of VTE events in the year following kidney transplant was 3.8%. VTE occurred in 4.1% of recipients treated with statins and 3.8% of the controls - (hazard ratio [HR] .92, 95% confidence interval [95% CI] .39, 2.21, p = .86). However, there were significant differences between the groups in terms of age, sex, race/ethnicity, body mass index, indication for transplant, diagnosis of diabetes and discharge antiplatelet or anticoagulant therapy. Following sensitivity analysis in which cohort matching was performed to account for these differences, there was no difference in VTE event-free survival (HR .89, 95% CI .41, 1.96, p = .78) or overall survival (HR .54, 95% CI .15, 1.94, p = .35) between patients treated with statins compared to controls.

CONCLUSION

Statin therapy in the year following successful kidney transplant was not associated with a reduction in risk of VTE.

Thrombosis Associated With Cytomegalovirus (CMV) in a Kidney Transplant Recipient

Cytomegalovirus (CMV) infection is a common infectious complication after kidney transplantation. Indirect effects of CMV infection include an increased risk of secondary infections, increased risk of acute rejection, and chronic allograft dysfunction. However, it is not well known that CMV may also increase the risk of venous and arterial thrombosis. Here, we present a case of acute deep venous thromboembolism associated with acute CMV disease in a kidney transplant recipient. We also performed a literature review of cytomegalovirus-associated thrombosis in immunocompromised individuals.

Statin Therapy and the Incidence of Thromboembolism and Vascular Events Following Liver Transplantation

Statin therapy may reduce the risk of venous thromboembolism (VTE), which may impact solid organ transplant outcomes. We evaluated the incidence of VTE and other complications after liver transplantation stratified by hyperlipidemia status and statin use using a retrospective cohort study approach. We reviewed all primary orthotopic liver transplantation (OLT) records from January 2014 to December 2019 from our center. Intraoperative deaths were excluded. Recipient, donor clinical and demographic data were collected. We developed risk-adjusted models to assess the effect of statin use on the occurrence of VTE, hepatic artery complications (HACs), graft failure, and death, accounting for clinical covariates and competing risks. A total of 672 OLT recipients were included in the analysis. Of this cohort, 11.9% (n = 80) received statin therapy. A total of 47 patients (7.0%) had VTE events. HACs occurred in 40 patients (6.0%). A total of 42 (6.1%) patients experienced graft loss, whereas 9.1% (n = 61) of the cohort died during the study interval. Eighty OLT recipients (29.8%) were treated with statins. In the statin treated group, 0% of patients had VTE versus 7.9% of those not on statins (P = 0.02). HACs were identified in 1.2% of the statin group and 6.8% of the nonstatin group. Untreated hyperlipidemia was associated with a 2.1-fold higher risk of HACs versus patients with no hyperlipidemia status (P = 0.05). Statin therapy was associated with significantly better risk-adjusted thromboembolic event-free survival (absence of VTE, cerebrovascular accident, myocardial infarction, HACs, and death); hazard ratio, 2.7; P = 0.01. These data indicate that statin therapy is correlated with a lower rate of VTE and HACs after liver transplantation.

Donor Graft Cytomegalovirus Serostatus and the Risk of Arterial and Venous Thrombotic Events in Seronegative Recipients After Non-Thoracic Solid Organ Transplantation

BACKGROUND

Cytomegalovirus (CMV) is the most common opportunistic pathogen, following solid organ transplantation (SOT), that leads to direct and indirect effects. The aim of this study was to assess the impact of CMV exposure at transplantation on the rate of posttransplant thrombotic events (TEs).

METHODS

We conducted a retrospective cohort study of patients transplanted at the University of Alberta Hospital between July 2005 and January 2018. We included adult SOT CMV-seronegative recipients at transplantation who received an allograft from either a seropositive donor (D+/R-) or a seronegative donor (D-/R-).

RESULTS

A total of 392 SOT recipients were included: 151 (39%) liver, 188 (48%) kidney, 45 (11%) pancreas, and 8 (2%) other transplants. The mean age was 47 years, 297 (76%) were males, and 181 (46%) had a CMV D+/R- donor. Patients in the CMV D+/R- cohort were slightly older (51 years versus 48 years in the D-/R- cohort; P = .036), while other variables, including cardiovascular risk factors and pretransplant TEs, were not different between groups. Overall, TEs occurred in 35 (19%) patients in the CMV D+/R- group, versus 21 (10%) in the CMV D-/R- group, at 5 years of follow-up (P = .008); the incidence rates per 100 transplant months were 5.12 and 1.02 in the CMV D+/R- and CMV D-/R- groups, respectively (P = .003). After adjusting for potential confounders with a Cox regression model, a CMV D+/R- transplantation was independently associated with an increased risk of a TE over 5 years (adjusted hazard ratio, 3.027; 95% confidence interval, 1.669-5.488).

CONCLUSIONS

A CMV D+/R- transplantation is associated with an increased risk of a TE posttransplantation.

Venous Thromboembolism in Pediatric Hematopoietic Cell Transplant: A Multicenter Cohort Study

Hematopoietic cell transplant (HCT) is associated with a proinflammatory, procoagulant environment that places recipients at increased risk of venous thromboembolism (VTE). Although the incidence of VTE in adult HCT recipients has been extensively studied, similar data for children are lacking. We conducted a multicenter retrospective study to analyze the prevalence of VTE and associated risk factors in a large cohort of patients who underwent HCT at tertiary care US children's hospitals. The Pediatric Health Information System database, a large administrative database that contains clinical and resource utilization data from 49 freestanding children's hospitals in the United States, was used to extract data. International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify HCT recipients, VTE events, post-HCT complications, and associated risk factors up to 1 year post-transplant. Data on patients who received HCT from January 2010 through September 2014 were collected. A total of 4158 unique patients mean ± standard deviation age at transplant admit, 8.8 ± 6.5 years; range, birth to 33.4 years) were identified. After HCT 290 subjects (6.9%) developed VTE. VTE prevalence was greater in patients aged ≥ 13 versus <13 years (8.54% versus 6.33%; P = .01) and in recipients of allogeneic versus autologous grafts (7.7% versus 5%; P ≤ .01). VTE was associated with prolonged median duration of hospitalization (81 versus 54 days; P ≤.01) and increased 1-year mortality (13.9% versus 5.9%; P ≤ .01). Infections and presence of any graft-versus-host disease (GVHD) were significantly associated with VTE occurrence in recipients of allogenic grafts. Prevalence of VTE in patients who underwent HCT at pediatric tertiary care hospitals is about 7%. Age ≥ 13 years and allogeneic grafts were significant pre-HCT VTE risk factors, with GVHD and infections seen more frequently in patients with VTE.

Acute cytomegalovirus infection in liver transplant recipients: An independent risk for venous thromboembolism

Acute cytomegalovirus (CMV) infection is a commonly encountered complication in the post liver transplant setting. We present a case of a 71-year-old male with acute CMV infection, initially presenting with a gastrointestinal bleed due to acute CMV gastritis and later on complicated by acute venous thromboembolism occurring as an unprovoked event in the post liver transplant period. Traditional risk factors for venous thromboembolism have been well described in the medical literature. Sporadic cases of thromboembolism due to CMV infection in the immune compromised patients have been described, especially in the post kidney transplant patients. Liver transplant recipients are equally prone to CMV infection particularly in the first year after successful transplantation. Venous thromboembolism in this special population is particularly challenging due to the fact that these patients may have persistent thrombocytopenia and anticoagulation may be a challenge for the treating physician. Since liver transplantation is severely and universally limited by the availability of donor organs, we feel that this case report will provide valuable knowledge in the day to day management of these patients, whose clinical needs are complex and require a multidisciplinary approach in their care and management. Evidence and pathophysiology linking both the conditions is presented along with a brief discussion on the management, common scenarios encountered and potential impact in this special group of patients.

Cytomegalovirus-induced cutaneous microangiopathy manifesting as lower limb ischemia in a human immunodeficiency virus-infected patient

Cutaneous infections by cytomegalovirus (CMV) are rare and often difficult to diagnose both clinically and histopathologically. A wide range of different clinical manifestations have been described in the literature, especially in immunosuppressed patients. CMV-induced thrombosis has also been reported in these patients, and various mechanisms have been proposed to explain the role of CMV in the thrombotic process, including direct damage of the endothelial cells, activation of coagulation factors and inducing the production of antiphospholipid antibodies. We present the case of a human immunodeficiency virus (HIV)-infected woman who developed distal ischemic lesions of the lower extremities during a generalized CMV infection. We discuss the role of CMV and antiphospholipid antibodies in the pathogenesis of thrombosis in immunosuppressed patients.

Cytomegalovirus infection is associated with venous thromboembolism of immunocompetent adults--a case-control study

Cytomegalovirus (CMV) seems to contribute to the development of venous thromboembolism (VTE) in immunocompromised patients whereas literature data on the role in immunocompetent individuals are mainly limited to case reports. This study aimed to investigate if cytomegalovirus infection contributes to the development of VTE in immunocompetent individuals. CMV-IgG and CMV-IgM antibody titres, CMV-IgG avidity and CMV-DNA were identified in samples from 166 VTE patients and from 166 healthy blood donors matched for gender and age. CMV-IgG antibodies were found more frequently in VTE patients compared to controls [57.8% vs. 44.0%; adjusted OR 1.75 (95% CI 1.13-2.70); p = 0.016]. Accordingly, median CMV-IgG titres were significantly higher in the case group (89.4 vs. 1.8 AU/ml; p = 0.002). Although the overall rate was low, CMV-IgM antibodies were detected more often among cases than controls. The difference was significant in patients with an unprovoked VTE event [7.4% vs. 0.6%; adjusted OR 5.26 (95% CI 1.35-20.8); p = 0.017]. CMV-IgG antibodies of almost all VTE patients (98.9%) and controls (98.6%) were found to be of high avidity. The rate of positive CMV-DNA samples was low and not different between cases and controls. With the exception of age, no association was found between CMV seropositivity and established VTE risk factors within the VTE group. CMV infection seems to play a role in the development of VTE in immunocompetent patients. Recurrent infection might be more important than acute CMV infection.

Thrombosis associated with acute cytomegalovirus infection: a meta-analysis

BACKGROUND

Thrombosis associated with acute cytomegalovirus (CMV) infection has been reported in the medical literature almost 100 times thus far. Still, the clinical characteristics of patients with both conditions have never been systematically reviewed and described.

METHODS

A literature search was conducted for all (n=97) reports concerning thrombosis associated with acute CMV infection. The current knowledge concerning this unique association and previous clinical experience are presented here.

RESULTS

The incidence of thrombosis among acute CMV infection hospitalized patients was 6.4%, and the incidence of acute CMV infection among thrombosis hospitalized patients was 1.9-9.1%. Most (n=64; 65.9%) reported patients were immunocompetent. Mean age of reported patients was 39.7 ± 14.9 years. Female-male ratio was 1:1. DVT/PE, splanchnic vein thrombosis and splenic infarction were the most prevalent thromboses associated with acute CMV infection. While DVT/PE was more prevalent among immunocompromised patients, splanchnic vein thrombosis was more prevalent among immunocompetent patients. Inherited predispositions for thrombosis were significantly more prevalent among immunocompetent patients. Immunocompromised patients were treated with antiviral agents significantly more often. Duration of anticoagulation therapy varied significantly between reported patients. In-hospital mortality rates were 4.9-22.2%.

CONCLUSIONS

We believe physicians should be alert for symptoms and signs of thrombosis in patients with acute CMV infection, and for symptoms and signs of acute CMV infection in patients with thrombosis.

Pulmonary embolism and pulmonary infarction after lung transplantation

Venous thromboembolism (VTE), which includes pulmonary embolism (PE) and deep vein thrombosis (DVT), is a common occurrence in patients undergoing surgery and is a potentially fatal complication. Especially after lung transplantation, vascular complications can compromise the function of the allograft and limit survival. Typically, the risk of pulmonary infarction after PE in lung transplant recipients is high because the absence or poor development of the collateral bronchial circulation may predispose lung transplant recipients to pulmonary infarction. This article reports 2 cases of PE with associated pulmonary infarction after lung transplantation with significant morbidity.

The incidence of and risk factors for venous thromboembolism (VTE) and bleeding among 1514 patients undergoing hematopoietic stem cell transplantation: implications for VTE prevention

Venous thromboembolism (VTE) is increasingly diagnosed among individuals with hematologic malignancies. However, the risk of VTE among patients undergoing hematopoietic stem cell transplantation (HSCT) is unclear. We examined the incidence and risk factors for VTE and bleeding among 1514 patients undergoing in-patient HSCT. No protocolized VTE prophylaxis was used. By HSCT day 180, 75 symptomatic VTE occurred in 70 patients (4.6%; 95% confidence interval [CI], 3.6%-5.8%). Fifty-five (3.6%) were catheter-associated, 11 (0.7%) were non-catheter-associated deep venous thromboses, and 9 (0.6%) were pulmonary emboli. Thirty-four percent of VTE occurred at a platelet count less than 50 x10(9)/L; 13% occurred at a platelet count less than 20 x10(9)/L. In multivariate analysis, VTE was associated with prior VTE (odds ratio [OR], 2.9; 95% CI, 1.3-6.6) and with graft-versus-host disease (GVHD; OR, 2.4; 95% CI, 1.4-4.0). Clinically significant bleeding occurred in 230 patients (15.2%; 95% CI, 13.4%-17.1%); 55 patients (3.6%; 95% CI, 2.7%-4.7%) had fatal bleeding. Bleeding was associated with anticoagulation (OR, 3.1; 95% CI, 1.8-5.5), GVHD (OR, 2.4; 95% CI, 1.8-3.3), and veno-occlusive disease (OR, 2.2; 95% CI, 1.4-3.6). In HSCT patients, VTE is primarily catheter-related and 3-fold less common than clinically significant bleeding. These findings warrant consideration when selecting VTE prophylaxis in HSCT patients.

Microbial risk factors of cardiovascular and cerebrovascular diseases: potential therapeutical options

Infection and inflammation may have a crucial role in the pathogenesis of atherosclerosis. This hypothesis is supported by an increasing number of reports on the interaction between chronic infection, inflammation, and atherogenesis. Assessment of serological and inflammatory markers of infection may be useful adjuncts in identifying those patients who are at a higher risk of developing vascular events, and in whom more aggressive treatments might be warranted.

Infection of human endothelium in vitro by cytomegalovirus causes enhanced expression of purinergic receptors: a potential virus escape mechanism?

BACKGROUND

Human cytomegalovirus (CMV) uses different strategies to escape from human host defense reactions. Previously we have observed that infection of endothelial cells with CMV in vitro leads to enhanced activity of endothelial ectonucleotidases. These ectoenzymes are responsible for hydrolysis of extracellular adenine nucleotides, resulting in the formation of adenosine. Infection with CMV in vivo therefore may result in local increase of adenosine production, providing an anti-inflammatory and antiaggregatory microenvironment, which may facilitate entry of the virus into the target cell.

METHODS

The present study focuses on the expression of P2 type purinergic receptors on endothelial cells after infection with CMV. Human endothelial cells were infected with CMV and compared with either uninfected cells or endothelial cells infected with other herpesviruses (herpes simplex virus [HSV] 1 or 2) for the expression of P2 receptors such as P2Y1, P2Y2, or P2X7. For comparison, cells stimulated with nonspecific agents were also studied.

RESULTS

A strong upregulation of the P2 receptors tested was shown, exclusively in CMV-infected cells. Stimulation with either HSV-1 or HSV2, nonspecific stimulants, or various cytokines did not affect the expression of these P2 receptors significantly.

CONCLUSION

Infection of endothelium with CMV causes significant upregulation of the P2 receptors studied. As these receptors may potentially be able to concentrate nucleotides along the ectonucleotidases of the endothelial cell membrane, rapid local hydrolysis of adenosine triphosphate and adenosine diphosphate may be facilitated by enhanced P2 receptor expression. Such a CMV induced mechanism might enable the virus to escape from an important host defense response, such as local microthrombus formation.

Association between cytomegalovirus infection and venous thromboembolism

It has been suggested that cytomegalovirus (CMV) infection may be associated with thrombosis in immunocompromised patients. In addition, an association between CMV infection and thrombotic events in immunocompetent hosts has been sporadically reported. We report on 1 immunocompromised and 8 immunocompetent adults who were admitted to a tertiary medical center and experienced a venous thromboembolic event during CMV infection. None reported previous thromboembolic events. All patients were diagnosed as suffering from acute CMV infection. Seven of the patients had vein thromboses. Significant additional thrombophilia was identified in 5 patients; 1 had 15.3 U/mL anti-cardiolipin IgM antibodies (elevated >7), 2 others were not evaluated for genetic procoagulant tendency. The exact nature of the procoagulant effect of CMV has not yet been clarified. Even though these mechanistic studies are incomplete, we suggest that from the clinical perspective, the presence of CMV infection should be considered a possible risk factor for thrombophilia, justifying a high index of suspicion for possible thrombotic events and subsequent decisions regarding prophylactic anticoagulation.

Risk Factors for Venous Thromboembolism After Lung Transplantation

BACKGROUND

The risk factors for venous thromboembolism (VTE) following lung transplantation are not well established. We aimed to estimate the incidence of VTE and to identify the risk factors for VTE after lung transplantation.

METHODS

We performed a nested case-control study within the cohort of 121 patients who underwent lung transplantation at our center between August 2001 and July 2005. Control subjects were matched to case patients on the number of days from the time of transplant. Cox proportional hazards models were used to identify risk factors for VTE.

RESULTS

Twenty-four patients had deep vein thromboses, and 6 patients had pulmonary emboli (3 patients had both) [22% of the cohort]. In multivariate models, older age (p < 0.05), diabetes mellitus (p = 0.03), and pneumonia (p = 0.02) were associated with a higher rate of VTE.

CONCLUSIONS

VTE is a frequent complication of lung transplantation. Older age, diabetes, and pneumonia increase the rate of VTE. Future studies of intensive VTE prophylaxis may be warranted.

Acute cytomegalovirus infection complicated by venous thrombosis in a renal transplant recipient

We report a case of simultaneous acute cytomegalovirus infection and venous thrombosis in a renal transplant recipient. On posttransplant month 3, the patient started complaining of left leg pain and swelling. Tibiopopliteal and femoral deep venous thrombosis were confirmed by Doppler ultrasonography. A serological test for CMV ELISA was strongly positive for IgM antibodies. Acute CMV infection was diagnosed by serum quantitative DNA polymerase chain reaction. Genetic predisposing risk factors for thrombosis (eg, protein C and S deficiency, factor V Leiden and prothrombin G20210A mutations, and antithrombin III deficiency) were not present. Results of tests for anticardiolipin antibodies, lupus anticoagulant, and antinuclear antibodies were also negative. No other clinical or biologic risk factors for thrombosis were detected in the patient. The patient responded well to intravenous gancyclovir and low-molecular weight heparin therapy. He was discharged in good condition. Our observation suggests that acute CMV infection may be the cause of a thrombotic event in renal transplant recipients.

Perioperative concerns for transplant recipients undergoing nontransplant surgery

At some time in a general surgeon's career it is likely that they will be asked to care for a surgical problem in a transplant recipient. In many instances, the treating surgeon may opt for transferring the patient to a transplant center more familiar with organ transplant recipients, but at other times transfer may not be the optimal option for the patient. This article is intended to touch on some of the more common situations that a general surgeon in community practice might encounter in dealing with organ transplant recipients, and highlight perioperative and in a few cases, intraoperative, concerns.

Acute cytomegalovirus infection and venous thrombosis: role of antiphospholipid antibodies

Cytomegalovirus (CMV)-induced thrombosis has been reported in immunocompromised patients, such as transplant recipients and patients with AIDS. Recent cases also describe thrombotic phenomena in immunocompetent patients with CMV infection. Various mechanisms may explain the role of CMV in thrombosis: this virus can damage endothelial cells, activate coagulation factors, and induce production of antiphospholipid (aPL) antibodies. We present a case report of a previously healthy white woman with a pulmonary embolism associated with CMV infection and the presence of aPL antibodies, and we discuss the role of the aPL antibodies associated with CMV infection in the pathogenesis of thrombosis.

Acute portal and mesenteric thrombosis: unusual presentation of cytomegalovirus infection

Cytomegalovirus infection is a benign disease in immunocompetent patients. In-vitro and in-vivo studies show that cytomegalovirus may cause arterial and venous thrombosis through different mechanisms. We describe two cases of acute cytomegalovirus infection complicated by portal and mesenteric vein thrombosis leading to intestinal ischemia. Both patients carried the heterozygous prothrombin G20210A mutation. The presence of this unusual complication should be searched for in patients with acute cytomegalovirus infection and abdominal symptoms in order to start early anticoagulation. The necessity for full thrombophilic screening is also pointed out.

Cytomegalovirus-associated bleeding diathesis in renal transplant recipients

Cytomegalovirus (CMV) infection is reported to be capable of modifying endothelial surface with subsequent increased risk of thromboembolic complications. Nevertheless, there are only sparse reports on its role in the development of bleeding diathesis. Here we report two renal transplant recipients who manifested severe coagulation disorders associated with acute CMV infection. Antiviral therapy was followed by consistent correction of coagulation abnormalities.