Influence of primary cancer site on clinical outcomes of anticoagulation for associated venous thromboembolism

INTRODUCTION

The outcome of anticoagulation for cancer-associated venous thromboembolism (Ca-VTE) differs according to cancer location, but data are limited and inconsistent.

MATERIALS AND METHODS

Patients with acute venous thromboembolism (VTE) enrolled between 03/01/2013 and 04/30/2021 were followed prospectively to assess VTE recurrence, major bleeding (MB), clinically relevant non-major bleeding (CRNMB), and death.

RESULTS

There were 1702 (45.3 %) patients with Ca-VTE including: gastrointestinal (n = 340), pancreatic (n = 223), hematologic (n = 188), genitourinary (n = 163), lung (n = 139), ovarian (n = 109), breast (n = 97), renal (n = 75), prostate (n = 73), hepatobiliary (n = 70), brain (n = 57), and other cancers (n = 168); 2057 VTE patients had no cancer (NoCa-VTE). Hepatobiliary cancer had the highest VTE recurrence (all rates 100 person-years) of all cancers and higher compared to NoCa-VTE (13.69, p = 0.01), while the MB rate, although numerically higher (15.91), was not different (p = 0.09). Another 3 cancers had higher VTE recurrence but similar MB rates compared to NoCa-VTE: genitourinary [(9.59, p = 0.01) and (7.03, p = 1.0)], pancreatic [(9.74, p < 0.001) and (5.47, p = 1.00)], and hematologic [(5.29, p = 0.05) and (3.59, p = 1.0)]. Renal cancer had the highest rate of MB among all cancers and was higher than that of NoCa-VTE (16.49; p < 0.001), with no difference in VTE recurrence (1.62; p = 1.0). VTE recurrence and MB rates were not significantly different between NoCa-VTE and gastrointestinal, lung, breast, prostate, and brain cancers. CRNMB rates were similar and mortality higher in Ca-VTE patients, except for prostate and breast cancer, compared to NoCa-VTE.

CONCLUSIONS

Significant differences in clinical outcomes indicate that anticoagulation strategies may need to be tailored to the primary cancer location.

Survival Implications of Thrombus Recurrence or Bleeding in Cancer Patients Receiving Anticoagulation for Venous Thromboembolism Treatment

BACKGROUND

 Study aims were to analyze prospectively collected data from patients with cancer-associated venous thromboembolism (VTE) to determine the impact of VTE recurrence and anticoagulant-related bleeding on all-cause mortality.

PATIENTS/METHODS

 Consecutive cancer patients with acute VTE treated with anticoagulants (March 1, 2013-November 30, 2021) were included in this analysis. Anticoagulant therapy-associated VTE recurrences, major bleeding, and clinically relevant nonmajor bleeding (CRNMB) were assessed for their impact on all-cause mortality outcomes.

RESULTS

 This study included 1,812 cancer patients with VTE. Of these, there were 97 (5.4%) with recurrent VTE, 98 (5.4%) with major, and 104 (5.7%) with CRNMB while receiving anticoagulants. Recurrent VTE (hazard ratio [HR]: 1.52; 95% confidence interval [CI]: 1.16-2.00; p = 0.0028), major bleeding (HR: 1.82; 95% CI: 1.41-2.31; p = 0.006), and CRNMB (HR; 1.38; 95% CI: 1.05-1.81; p = 0.018) each adversely influenced mortality outcomes. Deep vein thrombosis as the incident thrombotic event type was associated with VTE recurrence (HR: 1.78; 95% CI: 1.08-2.89; p = 0.02). Neither cancer type nor stage, chemotherapy, or Ottawa risk category influenced VTE recurrence. Higher body weights (HR: 1.01; 95% CI: 1.00-1.01; p = 0.005) were associated with increased major bleeding, while high Ottawa scores (HR: 0.66; 95% CI: 0.46-0.96; p = 0.03) and apixaban treatment (HR: 0.62; 95% CI: 0.45-0.84; p = 0.002) were associated with fewer major bleeding outcomes.

CONCLUSION

 Among cancer patients receiving anticoagulant therapy for VTE, adverse outcomes such as VTE recurrence, major bleeding, or CRNMB increase mortality risk by 40 to 80%. Identifying variables predicting these outcomes may help risk-stratify patients with poor prognosis.

Incidental pulmonary embolism in cancer and noncancer patients: Prospective cohort study

BACKGROUND

Clinical picture and outcome of incidental pulmonary embolism (iPE) compared to symptomatic pulmonary embolism (sPE) remain unclear.

METHODS

Demographics, recurrent venous thromboembolism (VTE), mortality, major bleeding, and clinically relevant nonmajor bleeding (CRNMB) were compared between iPE and sPE patients who were followed prospectively at Mayo Thrombophilia Clinic (March 1, 2013 to August 1, 2020).

RESULTS

Out of 3576 VTE patients, 1417 (39.6%) had PE: 562 (39.7%) iPE and 855 sPE. Patients with cancer were more likely to have iPE (400 iPE vs. 314 sPE) compared to those without cancer (162 iPE vs. 541 sPE). VTE recurrence rate (all per 100 person-years) was similar in all iPE and sPE patients (3.34 vs. 3.68, p = .50), with cancer (4.16 vs. 4.89, p = .370), and without cancer patients (0.89 vs. 2.80, p = .25). Higher mortality observed in all patients with iPE compared to sPE (46.45 vs. 23.47, p < .001) and with cancer (56.41 vs. 45.77, p = .03) became not significant after adjustment for age, antiplatelet therapy, metastases, and cancer location. Noncancer iPE patients had higher mortality (15.95 vs. 7.18, p = .006) even after adjustment (p = .05). The major bleeding rate was also higher in all patients iPE compared to sPE (7.10 vs. 3.68, p = .03), but not after adjustment (p = .974); higher major bleeding rate in noncancer patients (6.49 vs. 1.25, p = .007) remained significant after adjustment (.02). CRNMB rate was similar to iPE and sPE patients.

CONCLUSION

iPE represents a more serious clinical condition compared to sPE as indicated by the higher mortality and major bleeding but these differences reflect underlying comorbidities rather than the seriousness of the embolic event.

Pulmonary artery capacitance and pulmonary vascular resistance as prognostic indicators in acute pulmonary embolism

Aims

The non-invasive calculation of right ventricular (RV) haemodynamics as pulmonary artery (PA) capacitance (PAC) and pulmonary vascular resistance (PVR) have proved to be feasible, easy to perform, and of high prognostic value. We, therefore, evaluated whether baseline PAC and PVR could predict clinical outcomes for patients with acute pulmonary embolism (PE).

Methods and results

We prospectively followed 373 patients [mean (standard deviation) age, 64.1 (14.9) years; 58.4% were men, and 27.9% had cancer] who had acute PE and transthoracic echocardiography within 1 day of diagnosis from 1 March 2013 through 30 June 2020. Pulmonary artery capacitance was calculated as left ventricular stroke volume/(PA systolic pressure − PA diastolic pressure). Pulmonary vascular resistance was calculated as (tricuspid regurgitant velocity/RV outflow tract velocity time integral) × 10 + 0.16. These two variables were calculated retrospectively from the values obtained with transthoracic echocardiography. Pulmonary artery capacitance was acquired in 99 (27%) patients and PVR in 65 (17%) patients. Univariable and bivariable logistic regression analyses, and receiver operating characteristic curves were used to evaluate the ability of these haemodynamic measurements to predict mortality up to 6 months. After using bivariable models to adjust individually for age, cancer, and pulmonary hypertension. Pulmonary vascular resistance was associated with all-cause mortality at 3 months [area under the curve (AUC) 0.75, 95% confidence interval (CI) 0.61–0.86; P = 0.01], and 6 months (AUC 0.81; 95% CI 0.69–0.91; P≤ 0.03). Pulmonary artery capacitance was associated with all-cause mortality at 30 days (AUC 0.95; 95% CI 0.82–0.99; P &lt; 0.001) and 3 months (AUC 0.84; 95% CI 0.65–0.99; P = 0.003).

Conclusion

Non-invasive measurement of RV haemodynamics could provide prognostic information of patients with acute PE. Pulmonary artery capacitance and PVR are potentially important predictors of all-cause mortality in these patients and should be explored in future studies.

Single versus multiple and incidental versus symptomatic subsegmental pulmonary embolism: clinical characteristics and outcome

It remains unexplored if the clinical picture and outcome of subsegmental pulmonary embolism (SSPE) differ between single versus multiple, and incidental versus symptomatic embolism. Consecutive patients anticoagulated for SSPE at the Mayo Thrombophilia Clinic (03/01/2013-12/31/2020) were followed forward to assess venous thromboembolism (VTE) recurrence, mortality, major bleeding, and clinically relevant non-major bleeding (CRNMB); expressed as a rate per 100 person-years. Among 3878 VTE patients, 1541 had pulmonary embolism including 224 (14.6%) with SSPE either single (n = 139) or multiple (n = 85; 46 bilateral and 39 unilateral emboli); 134 had incidental and 90 symptomatic SSPE. Patients with single were less often symptomatic and less often had coexisting DVT than multiple SSPE. Patients with incidental had a two-fold higher frequency of cancer compared to symptomatic SSPE. During the study period, 1 patient with single and 2 with multiple SSPE had VTE recurrence (rate of 1.14 vs 3.63, p = 0.280). Single SSPE patients experienced 2 episodes of major bleeding (rate of 2.36) while the multiple SSPE group had no major bleeding. Seven patients in each group had CRNMB events (rate of 8.20 vs 13.58 for single and multiple SSPE, respectively, p = 0.282). Patients with single SSPE had a higher death rate compared to multiple SSPE (43.07 vs 22.22, p = 0.031) but no difference was noted after adjusting for cancer (p = 0.388). Also, incidental had similar clinical outcomes to symptomatic SSPE.Interpretation Anticoagulated SSPE patients with single and multiple as well as incidental and symptomatic have a different clinical profile but similar clinical outcomes.

Bleeding in Patients With Gastrointestinal Cancer Compared With Nongastrointestinal Cancer Treated With Apixaban, Rivaroxaban, or Enoxaparin for Acute Venous Thromboembolism

OBJECTIVE

To compare the bleeding risk in patients with gastrointestinal (GI) cancer with that in patients with non-GI cancer treated with anticoagulation for acute cancer-associated venous thromboembolism (Ca-VTE).

PATIENTS AND METHODS

Consecutive patients with Ca-VTE seen at the Mayo Thrombophilia Clinic between March 1, 2013, and April 20, 2020, were observed prospectively to assess major bleeding and clinically relevant nonmajor bleeding (CRNMB).

RESULTS

In the group of 1392 patients with Ca-VTE, 499 (35.8%) had GI cancer including 272 with luminal GI cancer (lower GI, 208; upper GI, 64), 176 with pancreatic cancer, and 51 with hepatobiliary cancer. The rate of major bleeding and CRNMB in patients with GI cancer was similar to that in 893 (64.2%) patients with non-GI cancer treated with apixaban, rivaroxaban, or enoxaparin. Apixaban had a higher rate of major bleeding in luminal GI cancer compared with the non-GI cancer group (15.59 vs 3.26 per 100 person-years; P=.004) and compared with enoxaparin in patients with luminal GI cancer (15.59 vs 3.17; P=.04). Apixaban had a lower rate of CRNMB compared with rivaroxaban in patients with GI cancer (3.83 vs 9.40 per 100 person-years; P=.03). Patients treated with rivaroxaban in the luminal GI cancer group had a major bleeding rate similar to that of patients with non-GI cancer (2.04 vs 4.91 per 100 person-years; P=.37).

CONCLUSION

Apixaban has a higher rate of major bleeding in patients with luminal GI cancer compared with patients with non-GI cancer and compared with enoxaparin in patients with luminal GI cancer. Rivaroxaban shows no increased risk of major bleeding in patients with GI cancer or luminal GI cancer compared with patients with non-GI cancer.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03504007.

Pulmonary artery capacitance a simple and novel prognostic variable in acute pulmonary embolism

Background

The non-invasive calculation of right ventricular hemodynamics such as the pulmonary artery capacitance (PAC) has proven to be feasible and easy to perform. The simplified pulmonary embolism severity index (sPESI) and pulmonary vascular resistance (PVR) are other prognostic tools that have been used in the past.

Purpose

To evaluate if baseline PAC can outperform PVR and sPESI to predict all-cause short-term mortality in patients with acute pulmonary embolism (PE).

Methods

373 patients with acute PE and a transthoracic echocardiogram performed within one day of diagnosis from March 2013 through June 2020 were followed prospectively. PAC was calculated as: Left ventricular stroke volume/ (Pulmonary artery systolic pressure – Pulmonary artery diastolic pressure). PVR was calculated as: Tricuspid regurgitant velocity / Right ventricular outflow tract velocity time integral x 10 + 0.16. The sPESI was used to evaluate prognosis by categorizing patients into low and high-risk categories. Multiple logistic regression analyses and receiver-operating characteristic curves were used to evaluate the ability of PAC, PVR, and sPESI to predict all-cause mortality up to six months. The Youden index was used to determine the cut-off value with the highest sensitivity and specificity. Kaplan–Meier curves were performed to determine event-free survival rate, differences between groups were assessed using the Wilcoxon Test.

Results

Mean age was 64±15 years (58% male, 28% cancer). PAC was associated with mortality at thirty days (p 0.0003), three months (p 0.003), and six months (p 0.011) (Table). PVR was associated with mortality at thirty days, three months, and six months (p 0.045, 0.012, and 0.031 respectively). The sPESI score ≥1 (high risk) was associated with all-cause mortality at three months and six months (p 0.0136 and &lt;0.0001 respectively). PAC was the strongest predictor of all-cause mortality with an AUC of 0.95 (CI 0.82- 0.99) at thirty days, 0.84 (CI 0.65–0.99) at three months, and 0.77 (CI 0.57–0.96) for six months. Corresponding Kaplan-Meier survival curve of PAC and thirty days all-cause mortality is presented in the Figure. PVR had an AUC of 0.75 (CI 0.48–0.95) at thirty days, 0.79 (CI 0.58–0.94) at three months, and 0.72 (CI 0.50–0.90) at six months. The sPESI had an AUC of 0.62 (CI 0.54–0.66) at three months and 0.64 (CI 0.59–0.67) at six months.

Conclusion

In patients with acute PE, PAC outperforms sPESI and PVR as a predictor of short-term all-cause mortality at thirty days, three months, and six months. These three variables should be explored head to head prospectively for their utility to predict short term all-cause mortality.

Funding Acknowledgement

Type of funding sources: None.

Outcome of anticoagulation in isolated distal deep vein thrombosis compared to proximal deep venous thrombosis

BACKGROUND

Isolated, distal deep vein thrombosis (IDDVT) is thought to have low rates of propagation, embolization, and recurrence compared with proximal DVT (PDVT), but the data are limited.

OBJECTIVES

The objective of this study was to assess outcomes among patients with IDDVT compared with PDVT.

PATIENTS/METHODS

Consecutive patients with ultrasound-confirmed acute DVT (March 1, 2013-August 1, 2020) were identified by reviewing the Mayo Clinic Gonda Vascular Center and VTE Registry databases. Patients were divided into two groups depending on the DVT location (isolated, distal vs. proximal DVT). Outcomes including venous thromboembolism (VTE) recurrence, major bleeding, and death were compared by thrombus location and anticoagulant therapy, warfarin vs. direct oral anticoagulant (DOAC).

RESULTS

Isolated, distal deep vein thrombosis (n = 746) was more often associated with recent surgery, major trauma, or confinement (p < .001), whereas patients with PDVT (n = 1176) were more frequently unprovoked, had a prior history of VTE, or active cancer (p < .001). There was no overall difference in VTE recurrence or major bleeding between groups during follow-up. Patients with IDDVT had a higher death rate at 3 months (p = .001) and when propensity scored for cancer (p = .003). Independent predictors of mortality included warfarin (vs. DOAC) therapy, increasing age, and active cancer. DOAC therapy resulted in lower VTE recurrence, major bleeding, and death rates in both groups.

CONCLUSION

Outcomes of IDDVT including VTE recurrence and bleeding rates were similar to PDVT despite higher early mortality rates. Outcomes for both groups were positively influenced by the use of DOACs.

Delayed anticoagulation in venous thromboembolism: Reasons and associated outcomes

Objective

We assessed the number of cases with delayed anticoagulation initiation, explored the reasons for the delay, and its impact on outcome in patients with acute venous thromboembolism (VTE) treated in an organized setting of treatment initiation and continuous, prospective follow‐up.

Methods

Patients with anticoagulation initiation delay >24 hours were identified within the cohort of patients with acute VTE enrolled in the Mayo Clinic Venous Thromboembolism Registry between 2013 and 2020. The reasons for treatment delay were explored by reviewing the electronic database. VTE recurrence, all‐cause mortality, major bleeding, and clinically relevant nonmajor bleeding (CRNMB) were compared to those with no anticoagulation delay.

Results

Of 2378 patients with acute VTE, 100 (4.2%) experienced an anticoagulation delay. We identified seven reasons for treatment delays: deferring anticoagulation initiation to specialists (n = 38), thrombocytopenia (n = 10), planned or recent procedure (n = 16), active or recent bleeding (n = 12), missed diagnosis (n = 7), logistics (n = 6), and patient decision (n = 4). In seven cases, no reason was identified. We identified modifiable reasons for anticoagulation delay in 55%. At 90‐day follow‐up, patients with anticoagulation delay had a higher rate of mortality and major bleeding. VTE recurrence and CRNMB were not statistically different compared to those without anticoagulation delay. After adjustment for age, weight, and cancer, hazard ratios (HRs) for VTE recurrence and major bleeding remained elevated but not to a statistically significant level.

Conclusion

In the setting of a highly organized system of anticoagulation initiation, the incidence of treatment delay is low. Yet most delays could be avoided. A low number of cases provide insufficient power to evaluate the clinical consequences of anticoagulation initiation delay; however, elevated HR for VTE recurrence and major bleeding suggest association and need for further investigation.

Calf vein thrombosis outcomes comparing patients with and without cancer

Distal or calf deep vein thrombosis (DVT) are said to have low rates of propagation, embolization, and recurrence. The objective of this study was to determine outcomes among cancer patients with calf DVT compared to those without cancer. Consecutive patients with ultrasound confirmed acute calf DVT (3/1/2013-8/10/2019) were assessed for venous thromboembolism (VTE) recurrence and bleeding outcomes compared by cancer status. There were 830 patients with isolated calf DVT; 243 with cancer and 587 without cancer. Cancer patients were older (65.9 ± 11.4 vs. 62.0 ± 15.9 years; p = 0.006), with less frequent recent hospitalization (31.7% vs. 48.0%; p < 0.001), surgery (30.0% vs. 38.0%; p = 0.03), or trauma (3.7% vs. 19.9%; p < 0.001). The four most common cancers included hematologic malignancies (20.6%), lung (11.5%), gastrointestinal (10.3%), and ovarian/GYN (9.1%). Nearly half of patients had metastatic disease (43.8%) and 57% were receiving chemotherapy. VTE recurrence rates were similar for patients with (7.1%) and without cancer (4.0%; p = 0.105). Major bleeding (6.3% vs. 2.3%; p = 0.007) were greater for cancer patients while clinical relevant non major bleeding rates did not differ (7.1% vs. 4.6%; p = 0.159). In this retrospective analysis, cancer patients with calf DVT have similar rates of VTE recurrence but higher major bleeding outcomes compared to patients without cancer.

Calf Vein Thrombosis Comparison of Outcomes for Axial and Muscular Venous Thrombosis

BACKGROUND

 The objective of this study was to characterize clinical features and outcomes among patients with calf deep vein thrombosis (DVT) limited to the muscular veins compared with axial veins.

METHODS

 Consecutive patients with ultrasound confirmed acute DVT involving the calf veins (January 1, 2016-August 1, 2018) were identified from the Gonda Vascular Center ultrasound database. Patients were divided into axial or muscular groups based on thrombus location. Demographics, management, and outcomes were compared.

RESULTS

 Over the study period, there were 647 patients with calf DVT equally distributed between axial (n = 321) and muscular (n = 326) locations. Within these groups, peroneal and soleal veins were most commonly involved. Nearly all cases were provoked (97%). Synchronous pulmonary embolism (PE) were more common for axial (30.8%) compared to muscular groups (20.2%; p = 0.001); nearly one-third had no pulmonary symptoms. Anticoagulation for a median of 3 months was initiated for 85.5% of both groups. Venous thromboembolism (VTE) recurrence was more common in the axial group (15.9% vs. 7.1%, p = 0.0015) including more frequent DVT propagation (9.4% vs. 3.1%; p = 0.0017) and PE (3.4% vs. 0.6%; p = 0.0168). Major bleeding, clinically relevant nonmajor bleeding, and mortality rates did not differ between groups. Withholding anticoagulation led to more frequent thrombus propagation in the axial group (3.4% vs. 0.9%; p = 0.029).

CONCLUSION

 Several important features distinguish muscular from axial DVT. Axial DVT are more likely to have an associated PE and are more likely to experience recurrent VTE, particularly if anticoagulation is withheld.

Comparison of apixaban to rivaroxaban and enoxaparin in acute cancer-associated venous thromboembolism

To provide direct comparison between apixaban and rivaroxaban in patients with acute cancer-associated venous thromboembolism (Ca-VTE), consecutive patients treated with apixaban, rivaroxaban, or enoxaparin at Mayo Thrombophilia Clinic (March 1, 2013 to January 31, 2018)) were followed prospectively. The primary effectiveness outcome was venous thromboembolism (VTE) recurrence, and the secondary was mortality. The primary safety outcome was major bleeding, the secondary clinically relevant safety outcome was non-major bleeding (CRNMB), and the third a composite of major and CRNMB. There were 750 patients treated for acute Ca-VTE with apixaban (n = 224), rivaroxaban (n = 163), and enoxaparin (n = 363) within 14 days of diagnosis and for at least 3 months, or until study event. Recurrent VTE was diagnosed in 11 receiving apixaban, 7 receiving rivaroxaban (apixaban vs rivaroxaban hazard ratio (HR) 1.31, 95% confidence interval (95% CI) 0.51-3.36) and 17 in the enoxaparin receiving group (apixaban vs enoxaparin HR 1.14, 95% CI: 0.54, 2.42 and rivaroxaban vs enoxaparin HR 0.85, 95% Cl: 0.36, 2.06). There were 82 deaths in apixaban, 74 rivaroxaban (apixaban vs rivaroxaban HR 1.67, 95% Cl: 1.20, 2.33) and 171 in enoxaparin group (rivaroxaban vs enoxaparin HR 0.73, 95% Cl: 0.56, 0.96). Major bleeding occurred in 11 apixaban, 12 rivaroxaban (apixaban vs rivaroxaban HR 0.73, 95% Cl: 0.32, 1.66) and 21 enoxaparin group (apixaban vs enoxaparin HR 0.89, 95% Cl: 0.43, 1.84 and rivaroxaban vs enoxaparin HR 1.23, 95% Cl: 0.61, 2.50). The CRNMB rate was higher in rivaroxaban compared to apixaban (P = .03) and LMWH (P = .01) groups. Recurrence of VTE and major bleeding were similar in apixaban, rivaroxaban, and enoxaparin groups. Rivaroxaban was associated with higher CRNMB but lower mortality compared to apixaban and enoxaparin.

Apixaban and Rivaroxaban in Patients With Acute Venous Thromboembolism

OBJECTIVE

To compare the clinical efficacy and safety of apixaban with those of rivaroxaban for the treatment of acute venous thromboembolism (VTE).

PATIENTS AND METHODS

Consecutive patients enrolled in the Mayo Thrombophilia Clinic Registry (between March 1, 2013, and January 30, 2018) and treated with apixaban or rivaroxaban for acute VTE were followed forward in time. The primary efficacy outcome was VTE recurrence. The primary safety outcome was major bleeding; the second safety outcome was clinically relevant nonmajor bleeding (CRNMB); and the third was a composite of major bleeding or CRNMB.

RESULTS

Within the group of 1696 patients with VTE enrolled, 600 (38%) were treated either with apixaban (n=302, 50%) or rivaroxaban (n=298, 50%) within the first 14 days of VTE diagnosis and who completed at least 3 months of therapy or had a study event. Recurrent VTE was diagnosed in 7 patients (2.3%) treated with apixaban and in 6 (2%) treated with rivaroxaban (adjusted hazard ratio [aHR], 1.4; 95% CI, 0.5-3.8). Major bleeding occurred in 11 patients (3.6%) receiving apixaban and in 9 patients (3.0%) receiving rivaroxaban (aHR, 1.2; 95% CI, 0.5-3.2). Clinically relevant nonmajor bleeding was diagnosed in 7 patients (2.3%) receiving apixaban and in 20 (6.7%) receiving rivaroxaban (aHR, 0.4; 95% CI, 0.2-0.9). The rates of composite major bleeding or CRNMB were similar (aHR, 0.6; 95% CI, 0.3-1.2). Most study events occurred in patients with cancer.

CONCLUSION

In the setting of a standardized, guideline-directed, patient-oriented clinical practice, the efficacy and safety of apixaban and rivaroxaban for the treatment of acute VTE were comparable.

Spillover of Fatty acids during dietary fat storage in type 2 diabetes: relationship to body fat depots and effects of weight loss

Spillover of lipoprotein lipase-generated fatty acids from chylomicrons into the plasma free fatty acid (FFA) pool is an important source of FFA and reflects inefficiency in dietary fat storage. We measured spillover in 13 people with type 2 diabetes using infusions of a [(3)H]triolein-labeled lipid emulsion and [U-(13)C]oleate during continuous feeding, before and after weight loss. Body fat was measured with dual energy X-ray absorptiometry and computed tomography. Participants lost ∼14% of body weight. There was an ∼38% decrease in meal-suppressed FFA concentration (P < 0.0001) and an ∼23% decrease in oleate flux (P = 0.007). Fractional spillover did not change (P = NS). At baseline, there was a strong negative correlation between spillover and leg fat (r = -0.79, P = 0.001) and a positive correlation with the trunk-to-leg fat ratio (R = 0.56, P = 0.047). These correlations disappeared after weight loss. Baseline leg fat (R = -0.61, P = 0.027) but not trunk fat (R = -0.27, P = 0.38) negatively predicted decreases in spillover with weight loss. These results indicate that spillover, a measure of inefficiency in dietary fat storage, is inversely associated with lower body fat in type 2 diabetes.

Kinetics of saturated, monounsaturated, and polyunsaturated fatty acids in humans

Plasma free fatty acid (FFA) kinetics in humans are often measured with only one tracer. In study 1, healthy volunteers received infusions of [U-¹³C]linoleate, [U-¹³C]oleate, and [U-¹³C]palmitate during continuous feeding with liquid meals low (n = 12) and high (n = 5) in palmitate and containing three labeled fatty acids to measure FFA appearance and fractional spillover of lipoprotein lipase-generated fatty acids. Study 2 used an intravenous lipid emulsion to increase FFA concentrations during infusion of linoleate and palmitate tracers. In study 1, there were no differences in spillover of the three fatty acids for the low-palmitate meal, but linoleate spillover was greater than oleate or palmitate for the high-palmitate meal. In studies 1 and 2, clearance was significantly greater for linoleate than for the other FFAs. There was a negative correlation between clearance and concentration for each fatty acid in the two studies. In study 1, concentration and spillover correlated positively for oleate and palmitate but negatively for linoleate. In conclusion, linoleate spillover is greater than that of other fatty acids under some circumstances. Linoleate clearance is greater than that of palmitate or oleate, indicating a need for caution when using a single FFA to infer the behavior of all fatty acids.