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The limited utility of currently available venous thromboembolism risk assessment tools in gynecological oncology patients

Published:October 20, 2016DOI:https://doi.org/10.1016/j.ajog.2016.10.014
      To the Editors:
      We have read with interest the manuscript by Barber and Clarke-Pearson
      • Barber E.L.
      • Clarke-Pearson D.L.
      The limited utility of currently available venous thromboembolism risk assessment tools in gynecological oncology patients.
      because we share the interest on a topic of large impact. We have comments, however, regarding some of their conclusions.
      Although the title claims that the available risk assessment tools have limited utility, this is not an accurate generalization. The studied patients in the study by Barber and Clarke-Pearson
      • Barber E.L.
      • Clarke-Pearson D.L.
      The limited utility of currently available venous thromboembolism risk assessment tools in gynecological oncology patients.
      had a 1 month, 1.8% incidence of symptomatic venous thromboembolism (VTE) despite at least 95% compliance with prophylaxis. Consistent with prior literature on bariatric, orthopedic, oncologic surgery and current guideline opinion, this rate may be considered as high.
      • Steele K.E.
      • Canner J.
      • Prokopowicz G.
      • et al.
      The EFFORT trial: preoperative enoxaparin versus postoperative fondaparinux for thromboprophylaxis in bariatric surgical patients: a randomized double-blind pilot trial.
      • Lassen M.R.
      • Gallus A.
      • Raskob G.E.
      • et al.
      Apixaban versus enoxaparin for thromboprophylaxis after hip replacement.
      • Khorana A.A.
      The NCCN Clinical Practice Guidelines on Venous Thromboembolic Disease: strategies for improving VTE prophylaxis in hospitalized cancer patients.
      • Whitlock R.P.
      • Sun J.C.
      • Fremes S.E.
      • Rubens F.D.
      • Teoh K.H.
      American College of Chest Physicians
      Antithrombotic and thrombolytic therapy for valvular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.
      Thus, it is not surprising that the Caprini risk score (CRS) classified most gynecological cancer patients as individuals in need of pharmacological prophylaxis.
      Given that there was a presumed high thromboprophylaxis rate done with no stratification based on either CRS or Rogers score, one cannot conclude that the scores and consequently risk-based prophylaxis are inadequate. There was no appropriate standard for comparison or an organized strategy by risk tier. Moreover, although the authors interpret that the scores do not stratify the thrombosis risk among patients with gynecological malignancy, their findings show that higher Caprini and Rogers scores exhibited a matching higher probability of VTE with good statistical linearity. They actually found, in concordance with other authors, a subgroup of adequately classified patients with high VTE risk despite conventional prophylaxis.
      • Lobastov K.
      • Barinov V.
      • Schastlivtsev I.
      • Laberko L.
      • Rodoman G.
      • Boyarintsev V.
      Validation of the Caprini risk assessment model for venous thromboembolism in high-risk surgical patients in the background of standard prophylaxis.
      It is concerning that the authors used 2 different stratifications of the CRS (Table 2 vs Table 3) but did not clarify the rationale for using them interchangeably in the conclusion. In addition, many of the CRS variables were not available, which limits the interpretation, including the paradoxical VTE incidence in a misclassified CRS risk group. Indeed, contrary to the findings by Barber and Clarke-Pearson,
      • Barber E.L.
      • Clarke-Pearson D.L.
      The limited utility of currently available venous thromboembolism risk assessment tools in gynecological oncology patients.
      Stroud et al
      • Stroud W.
      • Whitworth J.M.
      • Miklic M.
      • et al.
      Validation of a venous thromboembolism risk assessment model in gynecologic oncology.
      have validated the CRS in a gynecology-oncology population. Among 1123 patients, the 3 month rate of VTE was 3.3% and the CRS accurately predicted all VTE events.
      What the authors have successfully presented is that both the Rogers and Caprini scores have a demonstrable linearity with respect to the occurrence VTE among patients with gynecological malignancies. What needs to be urgently defined is which intensity and duration of thomboprophylaxis shall be offered to patients with very high scores, which despite conventional prevention had a potentially fatal 1 month VTE >2% in the present study. The idea of personalized duration of prophylaxis is not a new concept and has been successfully implemented in other surgical entities.
      • Cassidy M.R.
      • Rosenkranz P.
      • McAneny D.
      Reducing postoperative venous thromboembolism complications with a standardized risk-stratified prophylaxis protocol and mobilization program.

      References

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        • Clarke-Pearson D.L.
        The limited utility of currently available venous thromboembolism risk assessment tools in gynecological oncology patients.
        Am J Obstet Gynecol. 2016; 215: 445.e1-445.e9
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        • Canner J.
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        Apixaban versus enoxaparin for thromboprophylaxis after hip replacement.
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        Validation of the Caprini risk assessment model for venous thromboembolism in high-risk surgical patients in the background of standard prophylaxis.
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        • Stroud W.
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      Linked Article

      • The limited utility of currently available venous thromboembolism risk assessment tools in gynecological oncology patients
        American Journal of Obstetrics & GynecologyVol. 215Issue 4
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          Use of risk assessment tools, such as the Caprini score or Rogers score, is recommended by national societies to stratify surgical patients by venous thromboembolism risk and guide prophylaxis. However, these tools were not developed in a gynecological oncology patient population, and their utility in this population is unknown.
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      • Reply
        American Journal of Obstetrics & GynecologyVol. 216Issue 3
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          We thank Dr Tafur et al for their comments on our article, which raises issues specific to the gynecologic oncology patient. Regarding the utility of the risk assessment tools, we agree that when the highest-risk group of the Caprini score is substratified (score ≥5 group divided into smaller groups), it is highly correlated with venous thromboembolism (VTE) as reported in Figure 1 of our paper.1
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