Prophylactic efficacy of low-dose dihydroergotamine and heparin in postoperative deep venous thrombosis following intra-abdominal operations

Thromboembolism prevention in surgery of digestive cancer

BACKGROUND

The venous thromboembolism is a common complication after surgical treatment in general and, in particular, on the therapeutic management on cancer. Surgery of the digestive tract has been reported to induce this complication. Patients with digestive cancer have substantial increased risk of initial or recurrent thromboembolism.

AIM

To provide to surgeons working in digestive surgery and general surgery guidance on how to make safe thromboprophylaxis for patients requiring operations in the treatment of their gastrointestinal malignancies.

METHODS

The guideline was based on 15 relevant clinical issues and related to the risk factors, treatment and prognosis of the patient undergoing surgical treatment of cancer on digestive tract. They focused thromboembolic events associated with operations and thromboprophylaxis. The questions were structured using the PICO (Patient, Intervention or Indicator, Comparison and Outcome), allowing strategies to generate evidence on the main primary bases of scientific information (Medline / Pubmed, Embase, Lilacs / Scielo, Cochrane Library, PreMedline via OVID). Evidence manual search was also conducted (BDTD and IBICT). The evidence was recovered from the selected critical evaluation using discriminatory instruments (scores) according to the category of the question: risk, prognosis and therapy (JADAD Randomized Clinical Trials and New Castle Ottawa Scale for studies not randomized). After defining potential studies to support the recommendations, they were selected by the strength of evidence and grade of recommendation according to the classification of Oxford, including the available evidence of greater strength.

RESULTS

A total of 53,555 papers by title and / or abstract related to issue were found. Of this total were selected (1st selection) 478 studies that were evaluated as full-text. From them to support the recommendations were included in the consensus 132 papers. The 15 questions could be answered with evidence grade of articles with 31 A, 130 B, 1 C and 0 D.

CONCLUSION

It was possible to prepare safe recommendations as guidance for thromboembolism prophylaxis in operations on the digestive tract malignancies, addressing the most frequent topics of everyday work of digestive and general surgeons.

Heparins and mechanical methods for thromboprophylaxis in colorectal surgery

BACKGROUND

Colorectal surgery implies higher risk of postoperative thromboembolic complications as deep venous thrombosis (DVT) and pulmonary embolism (PE) than general surgery. The best prophylaxis in general surgery is heparin and graded compression stockings. No systematic review on combination prophylaxis or on thrombosis prophylaxis in colorectal surgery has been published.

OBJECTIVES

To compare the incidence of postoperative thromboembolism after colorectal surgery using prophylactic methods focussing on heparins and mechanical methods alone and in combinations.

SEARCH STRATEGY

Electronic searches was performed in MEDLINE, EMBASE back to 1970. Abstract books from major congresses were handsearched as were reference lists from previously performed reviews.

SELECTION CRITERIA

RCT or CCT comparing prophylactic interventions and/or placebo. Outcomes were ascending venography, 125 I-fibrinogen uptake test, ultrasound methods, pulmonary scintigraphy. Studies, using thermographic methods, other isotopic methods, plethysmographic methods, and purely clinical methods as the only diagnostic measure were excluded. 558 studies were identified - 477 were excluded. Only 3 of the identified studies focused exclusively on colorectal surgery. Studies of general surgery contain considerable numbers of colorectal patients. The authors of 66 studies in general and/or abdominal surgery were contacted for retrieving the results from the colorectal patients. Answers were received from very few. 19 studies entered this review.

DATA COLLECTION AND ANALYSIS

All studies and all data extraction were performed independently by at least two of the authors. Outcome was deep venous thrombosis and/or pulmonary embolism. Analysis of bleeding complications were unfeasible. 12 meaningful outcomes were analysed by means of the fixed effects model with Peto Odds Ratios.

MAIN RESULTS

Heparins versus no treatment: Any kind of heparincompared to no treatment or placebo (comparison 07.03, 11 studies). Heparin is better in preventing DVT and/or PE with a Peto Odds ratio at 0.32 (95% Confidence Interval 0.20-0.53) Unfractionated heparin versus low molecular weight heparin (comparison 08.03, 4 studies). The two treatments were found equally effective in preventing DVT and/or PE with a Peto Odds ratio 1.01 (95% Confidence Interval 0.67-1.52). Mechanical methods (comparison 10.3, 2 studies). The combination of graded compression stockings and LDH is better than LDH alone in preventing DVT and/or PE with a Peto Odds ratio at 4.17 (95% Confidence Interval 1.37-12.70).

REVIEWER'S CONCLUSIONS

The optimal prophylaxis in colorectal surgery is the combination of graduated compression stockings and low-dose unfractionated heparin. The unfractionated heparin can be replaced with low molecular weight heparin.

Two strategies for prophylaxis of fatal postoperative pulmonary embolism. Cost-effectiveness analysis

While subcutaneous heparin is a standard prophylaxis for death from pulmonary embolism following general surgery, it has been suggested that adding the vasoconstricting drug dihydroergotamine would improve survival compared to heparin alone. Dihydroergotamine may be associated with rare but life-threatening side effects; thus, reduced mortality from pulmonary embolism could be offset by increased mortality from other causes. Because a clinical trial to examine this possibility would be impractical, we performed a cost-effectiveness analysis to evaluate the effects of prophylactic dihydroergotamine on mortality. Based on published data, despite its favorable effects on the prevention of deep vein thrombosis, the addition of dihydroergotamine did not appear to save lives when added to heparin as prophylaxis. Probabilistic sensitivity analysis demonstrated that even if published risk estimates are in error, substantial changes would still not support the conclusion that dihydroergotamine is life-saving. In the absence of clear potential for improved survival, the increased costs associated with dihydroergotamine provide reason to question its routine prophylactic use in general surgery.

Combination dihydroergotamine mesylate and heparin sodium with lidocaine HCl. Pharmacokinetics, mechanism of action, clinical efficacy, and adverse effects

Dihydroergotamine(DHE)-heparin combination offers a unique treatment modality for the prevention of deep vein thrombosis. The combination appears to affect all 3 limbs of Virchow's triad: hypercoagulability, venous stasis, and endothelial damage. In most efficacy studies, data indicated that the combination of DHE 0.5 mg and heparin 5000 IU was superior to low-dose heparin alone. Even when the efficacy of DHE-heparin was the same as that of heparin alone, the use of the combination allowed for a decrease in the heparin dose required.