Hepatic veins as a site of clot formation following liver resection

Post-hepatectomy venous thromboembolism: a systematic review with meta-analysis exploring the role of pharmacological thromboprophylaxis

PURPOSE

Patients undergoing hepatectomy are at moderate-to-high risk of venous thromboembolism (VTE). This study critically examines the efficacy of combining pharmacological (PTP) and mechanical thromboprophylaxis (MTP) versus only MTP in reducing VTE events against the risk of hemorrhagic complications.

METHODS

A systematic review of major reference databases was undertaken, and a meta-analysis was performed using common-effects model. Risk of bias assessment was performed using Newcastle-Ottawa scale. Trial sequential analysis (TSA) was used to assess the precision and conclusiveness of the results.

RESULTS

8 studies (n = 4238 patients) meeting inclusion criteria were included in the analysis. Use of PTP + MTP was found to be associated with significantly lower VTE rates compared to only MTP (2.5% vs 5.3%; pooled RR 0.50, p = 0.03, I² = 46%) with minimal type I error. PTP + MTP was not associated with an increased risk of hemorrhagic complications (3.04% vs 1.9%; pooled RR 1.54, p = 0.11, I² = 0%) and had no significant impact on post-operative length of stay (12.1 vs 10.8 days; pooled MD - 0.66, p = 0.98, I² = 0%) and mortality (2.9% vs 3.7%; pooled RR 0.73, p = 0.33, I² = 0%).

CONCLUSION

Despite differences in the baseline patient characteristics, extent of hepatectomy, PTP regimens, and heterogeneity in the pooled analysis, the current study supports the use of PTP in post-hepatectomy patients (grade of recommendation: strong) as the combination of PTP + MTP is associated with a significantly lower incidence of VTE (level of evidence, moderate), without an increased risk of post-hepatectomy hemorrhage (level of evidence, low).

Prospective implementation of a standardized screening protocol for deep venous thrombosis in abdominal surgical oncology patients

BACKGROUND AND OBJECTIVES

Venous thromboembolism (VTE) remains a major cause of perioperative morbidity and mortality despite implementation of prophylaxis guidelines. We sought to identify risk factors for occult deep venous thrombosis (DVT) following abdominal surgery for cancer and measure the clinical impact of a prospectively implemented standardized postoperative DVT screening protocol.

METHODS

Patients undergoing abdominal surgery for malignant indication were screened with early postoperative lower extremity duplex to identify DVT. Clinical and pathologic factors associated with DVT were identified.

RESULTS

Among 255 patients meeting study criteria, 25 (9.8%) had occult lower extremity DVT on routine postoperative screening. Prior history of VTE and lower preoperative hemoglobin were independently associated with DVT (OR, 9.05; P = 0.004; and OR, 1.27; P = 0.025, respectively). Preoperative chemotherapy within 1 year and thrombocytopenia were associated with DVT in univariate analyses only. Five patients developed postoperative pulmonary emboli (2.0%); three following negative duplex and two following positive duplex for distal DVT for which the patients were not therapeutically anticoagulated due to a contraindication. There were no pulmonary emboli in duplex-positive patients who were anticoagulated or who had vena cava filter placed.

CONCLUSION

Despite prophylaxis, the prevalence of occult DVT in abdominal oncologic surgery patients is considerable. Postoperative screening duplex can identify these events to guide management.

Review article: the aetiology of primary Budd-Chiari syndrome - differences between the West and China

BACKGROUND

China may have the largest number of Budd-Chiari syndrome (BCS) cases in the world (at least 1914 original papers were published, and at least 20 191 BCS patients were reported). Considering the discrepancy in the clinical profiles and preferred treatment selection of primary BCS between the West and China, understanding its aetiology in these two different regions is very important.

AIM

To review the data from large cohort studies and meta-analyses to illustrate the epidemiology of risk factors for BCS in the West and China.

METHODS

Relevant papers were identified by major English- and Chinese-language databases, conference abstracts, and by manual search.

RESULTS

Risk factors reviewed include myeloproliferative neoplasms (MPNs) and their related gene mutations, anti-phospholipid syndrome, paroxysmal nocturnal haemoglobinuria (PNH), hyperhomocysteinaemia and 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T mutation, factor V Leiden (FVL) and prothrombin G20210A mutations, inherited anti-thrombin, protein C and protein S deficiencies, pregnancy and puerperium, poverty, and family history.

CONCLUSIONS

We examined the differences in the aetiological distribution of BCS between the West and China. Several recommendations should be considered in Chinese BCS patients: (i) screening for hyperhomocysteinaemia and MTHFR mutation should be regularly performed; (ii) screening for MPNs, PNH, and anti-phospholipid syndrome should be selectively performed; (iii) inherited anti-thrombin, protein C, and protein S deficiencies should be actively explored; (iv) screening for FVL and prothrombin G20210A mutations may be unnecessary; and (v) the clinical significance of pregnancy and puerperium, poverty with bacterial infections and unsanitary environments, and family history as possible risk factors should never be neglected.

Safety and efficacy of a novel, dry powder fibrin sealant for hemostasis in hepatic resection

BACKGROUND/AIMS

Fibrocaps is a dry powder fibrin sealant containing human plasma-derived fibrinogen and thrombin. The safety, efficacy, and application methods for Fibrocaps were evaluated in an exploratory, first-in-human, noncomparative, clinical study.

METHODS

Patients with minor bleeding/oozing after elective partial hepatic resection had Fibrocaps applied to the bleeding site either directly from the vial or from a spray device, with manual pressure applied using a cellulose, collagen, or gelatin sponge, if needed. Safety was evaluated at screening and postoperative days 1, 2, and 5, and weeks 4 and 12. The formation of anti-thrombin antibodies was assessed at baseline, and after 4 and 12 weeks. Time to hemostasis (TTH) within 10 min was determined.

RESULTS

Twenty-nine patients were treated with Fibrocaps; 6 experienced serious adverse events that were not related to the course of treatment. Adverse events occurring in >10% of patients were nausea, constipation, hypotension, obstipation, hypokalemia, and postoperative pain. Most adverse events were mild or moderate in severity. No patient developed anti-thrombin antibodies. The percentage of patients who achieved hemostasis was 93%; the median TTH was 3.8 min (range 0.3-10.3). Manual pressure was applied with Fibrocaps in 19 patients and considered beneficial in most.

CONCLUSION

Fibrocaps was well tolerated in patients undergoing elective hepatic resection and resulted in rapid hemostasis. These safety and efficacy results support further clinical testing of this ready-to-use fibrin sealant as an adjunct to surgical hemostasis.

Pulmonary embolism after elective liver resection: a prospective analysis of risk factors

BACKGROUND & AIMS

Impairment of clotting factors after liver resection (LR) is considered to protect from the risk of pulmonary embolism (PE). We aimed at formally investigating the risk of PE after elective LR.

METHODS

From 2007 to 2009, 410 consecutive patients were prospectively analyzed to assess the risk of postoperative PE after LR with a thoracic CT scan, with or without a CT pulmonary angiography (CTPA). All patients were on a standardized thromboprophylaxis regimen.

RESULTS

PE was diagnosed in 24 (6%) patients within the first 10 postoperative days. Comparison between the PE group (n=24) and the non-PE group (n=386) showed a similar rate of metastatic liver disease (25 vs. 31%, p=0.308) but higher rates of BMI ≥ 25 kg/m(2) (75 vs. 46%, p=0.006), major LR (79 vs. 45%, p=0.003) and normal or minimally fibrotic liver parenchyma (92 vs. 73%, p=0.05). No patients with PE had inherited or acquired coagulation disorders. The 90-day mortality rate was similar in the two groups (4% vs. 3%, p=0.77), but the median hospital stay was longer in the PE group (20(IQR 16-27) vs. 11(IQR 8-16) days, p=0.001). On multivariate analysis, the independent predictors for PE were a BMI ≥ 25 kg/m(2) (adj. OR 5.27), major LR (adj. OR 3.13) and normal or minimally fibrotic liver parenchyma (adj. OR 4.21).

CONCLUSIONS

In addition to patient characteristics (high BMI), major resection and normal liver parenchyma increase the risk of PE after LR. This suggests that specific thromboembolic mechanisms are involved in liver regeneration and advocates more aggressive thromboprophylaxis in the high-risk groups.

Multivariate analysis of risk factors for pulmonary complications after hepatic resection

OBJECTIVE

To generate the first evaluation of risk factors for postoperative pulmonary complications (PPCs) after hepatectomy.

BACKGROUND

Postoperative pulmonary complications (PPCs) after surgery are associated with significant morbidity and have been shown to increase the length of hospital stays. Several studies have been conducted to identify the risk factors for PPCs after abdominal surgery.

METHODS

Between January 2006 and December 2009, 555 patients underwent elective hepatectomy. We prospectively collected and retrospectively analyzed demographic data, pathological variables, associated pathological conditions, and preoperative, intraoperative, and postoperative variables. The dependent variables studied were the occurrence of PPCs, pleural effusion, pneumonia, and pulmonary embolism.

RESULTS

Multivariate analysis identified 5 independent risk factors for global PPCs: prolonged surgery [odds ratio (OR) = 1], presence of a nasogastric tube (OR = 1.6), intraoperative blood transfusion (OR = 1.7), diabetes mellitus (OR = 2.7), and a transverse subcostal bilateral muscle cutting incision (OR = 3.4). There were 4 independent risk factors for pleural effusion: prolonged surgery (OR = 1), surgery on the right lobe of the liver (OR = 1.6), neoadjuvant chemotherapy (OR = 2), and a transverse subcostal bilateral muscle cutting incision (OR = 2.5). There were 3 independent risk factors for pneumonia: intraoperative blood transfusion (OR = 1.9), diabetes mellitus (OR = 2.2), and atrial fibrillation (OR = 3). For pulmonary embolism, history of previous thromboembolic events was identified as the only risk factor (OR = 8.8).

CONCLUSIONS

The correction of modifiable risk factors among the identified factors could reduce the incidence of PPCs and, as a consequence, improve patient outcomes and reduce the length of hospital stays.