Reduction of Venous Thromboembolism in Surgical Patients Using a Mandatory Risk-Scoring System: 5-Year Follow-Up of an American College of Surgeons National Surgical Quality Improvement Program


• Abdelrahman A. Nimeri, MD, FACS1
• Maysoon M. Gamaleldin, MD2
• Karen L. McKenna, RN, MPH2
• Nicolas P. Turrin, PhD3
• Bisher O. Mustafa, MD4


Background: Sheikh Khalifa Medical City’s (SKMC) surgery institute was identified as a high outlier in the incidence of venous thromboembolism (VTE; deep vein throm­bosis [DVT] and pulmonary embolism [PE]) based on the semiannual report of the Amer­ican College of Surgeon’s National Surgical Quality Improvement Program (ACS NSQIP) in June 2010. Aim: To report our rates of VTE at SKMC, the results, and 5-year follow-up after an ACS NSQIP quality improvement program. Methods: A multidisciplinary VTE task force was established in June 2010. We instituted a compulsory risk assessment for VTE and utilized the ACS NSQIP best practice guidelines to review cases of VTE. We pro­spectively evaluated the observed/expect­ed (O/E) ratio for DVT/PE after implement­ing the action plan. Results: The O/E ratio for PE/DVT in general and general/vascular (GV) surgery was 6.00 and 4.86 in June 2010. Our compliance with ordering antithrombotic prophylactic measures was as low and it im­proved to 100% and our O/E ratio decreased to 1.18 and 1.5 in July 2011 and stabilized for the next 4 years. Currently, our compliance with ordering antithrombotic prophylactic measures is 100%, and our last 2 O/E ratio for DVT/PE are 0.74 and 0.75 in GV surgery and 0.82 and 0.78 in the entire surgery institute, respectively, and we are considered an ex­emplary site of the ACS NSQIP in GV surgery. Conclusion: A compulsory risk assessment for VTE has led to an overall improvement in DVT/PE rates in the surgery institute and for GV surgery to become an exemplary site for the ACS NSQIP

venous thromboembolism, ACS NSQIP, quality improvement project.



The prevention of venous thromboembo­lism (VTE) in the hospital is a priority, since pulmonary embolism is the most common preventable cause of death in hospital ad­missions. The cost of VTE (deep venous thrombosis [DVT] and pulmonary embolism [PE]) is enormous. Most hospitalized patients will have at least one or more risk factors for developing VTE, and programs to protect these patients are vital in order to decrease the morbidity associated with the disease. Despite educational efforts, physician’s use of VTE prophylaxis remains low in many hos­pitals. Sheikh Khalifa Medical City (SKMC) was identified as a high outlier for VTE based on the semiannual report (SAR) of the ACS NSQIP in June 2010.4 In an internal audit, we found that our compliance with institut­ing prophylaxis against DVT/PE was low. We aimed to measure the impact of a quality im­provement project (QIP) in the reduction of VTE rates among surgical patients in SKMC.




The SKMC is a tertiary referral center with 790 beds and a Joint Commission Interna­tional (JCI)-accredited hospital. Our surgery institute has been an ACS NSQIP multispe­cialty participating site since August 2009, and we submit all our cases to the ACS NS­QIP, except transplant, cardiac, and pediat­ric surgery cases. Our study is a prospective evaluation of a QIP utilizing the risk-adjusted SARs of the ACS NSQIP at SKMC. The statis­tical statis­tical analysis of these risk adjusted reports is done by ACS NSQIP comparing SKMC to more than 450 other ACS NSQIP hospitals. The sampling of patients enrolled to the ACS NSQIP at SKMC is done randomly by an independent surgical clinical reviewer by a standardized sampling method similar to all other ACS NSQIP hospitals.

Our semiannual report (SAR) in 2010 identified the division of general/vascular (GV) surgery and the entire surgery insti­tute as high outliers (worse 90th percentile compared to other ACS NSQIP hospitals) for VTE. A hospital-wide multidisciplinary VTE task force was established in June 2010. The task force included members from surgery, nursing, quality, medicine, pharmacy, IT, the ACS NSQIP surgeon champion, and surgi­cal clinical reviewer and was chaired by an experienced hematologist. Our initial high rates of VTE represented in our high O/E ra­tios placed our institute as a high outlier for DVT/PE compared to other hospitals partici­pating in the ACS NSQIP.



An initial chart review of cases of VTE picked up by the ACS NSQIP showed that we were not always prescribing antithrom­botic prophylactic measures appropriately. In addition, we realized that we had poor ad­herence to risk assessment for VTE in many of our surgery patients admitted to SKMC. The recommendations of the task force were rolled out at the end of 2010 and included reviewing and updating the hospital’s VTE prophylaxis policy, physician and nursing staff education about the importance of per­forming VTE risk assessment, implementing a compulsory risk assessment to all patients undergoing surgery or being admitted to the surgery institute, and a continuous in­ternal audit to evaluate the compliance with implementation of accepted prophylactic measures for VTE was done. This compulsory risk assessment form was attached to each patient’s file whether the patient was ad­mitted through the emergency department or scheduled for elective surgery. Once the initial implementation phase of the VTE risk assessment form was done, the form was converted to an electronic form which was embedded in the electronic medical record (Figure 1). Furthermore, education about the importance of assessing patients for the risk of VTE both on admission and at discharge was done for the nursing and house staff.

To improve the compliance with perform­ing VTE risk assessment, a hard stop was in­stituted from the start of the implementation of the risk assessment if the VTE risk assess­ment form was not completed. Other efforts to improve compliance included reminders to fill the risk assessment form in our elec­tronic medical record to alert physicians and improve our compliance with instituting antithrombotic prophylactic measures. The physicians would be prompted when open­ing the patient’s electronic medical record to complete the VTE risk assessment form.

To help physicians in prescribing VTE prophylaxis, once the paper-based or elec­tronic form was completed, a score was calculated stratifying the patient’s VTE risk into low (0-1), moderate (2-3), and high (4 or more) for VTE. This stratification was linked to suggested prophylaxis for VTE based on the previously reported incidence of VTE ac­cording to the level of risk. Balancing the use of suggested pharmacologic prophylaxis for each group was the physician’s evaluation of the patients potential risk of bleeding. The risk assessment score is based on the Caprini et al VTE risk assessment scoring sys­tem.

Figure 1. Electronic medical record venous thromboembolism risk assessment form.


Patients with score of 2 to 4 received antithrombotic prophylaxis while admitted to the hospital if there was no contraindica­tion to anticoagulation, while patients with score 5 or above received chemoprophylaxis for 2 weeks postdischarge. We use low-mo­lecular-weight heparin 40 mg once a day for patients with BMI less than 40 kg/m2 and 40 mg twice daily for patients with BMI >40 kg/m2. In addition, we send anyone with a Caprini score of 5 or more on 2 to 3 weeks of antithrombotic prophylaxis.

To evaluate and monitor our progress, we elected to use the adherence to the use of the compulsory VTE risk assessment form on a monthly basis and the observed/expected (O/E) ratio for VTE every 6 months. Our re­sults were compared to the ACS NSQIPs uti­lizing the semiannual riskadjusted reports.


The data collected randomly by our in­dependent surgical clinical reviewer were submitted to the ACS NSQIP. The statistical analysis and risk adjustment that compares our VTE rates to other US ACS NSQIPs are done by the statistical team at the ACS NS­QIP headquarters in the United States.



During the study period, we enrolled 2280 patients from 2010 to 2014, and our cases enrolled in 2010 were lower than 100 because we enrolled in the ACS NSQIP in Au­gust 2009 (4 months of data collection). Our adherence to filling the VTE risk assessment improved from below 80% to 100%, and at the same time, our rates of VTE decreased from a high rate of 3.1% (3 of 98) in 2010 to 0.9% (6 of 637) in 2011 and stabilized at a low exemplary rate of 0.1% (1 of 735) and 0.2% (2 of 810) in 2013 and 2014, respectively. Similarly, the O/E ratio for VTE in general sur­gery and GV surgery decreased from a high outlier status of 6.00 confidence interval [CI] (1.24-17.5) and 4.86 CI (1.0-14.19) in 2010 to an exemplary O/E ratio of 0.74 CI (0.43-1.32) and 0.75 CI (0.42-1.32), respectively, in 2013 and 2014 (Figure 2 and Table 1).

Figure 2. Real-time risk and shrinkage-adjusted projected odds ratio report.

After implementation of the DVT/PE task force recommendations, the adherence to performing the VTE risk assessment im­proved to 100%. However, our adherence to prescribing antithrombotic prophylactic measures was still below 80% (Table 2).

In our last SAR, the O/E ratio for DVT/PE was 0.75 in general and GV surgery, and we are considered an exemplary site of the ACS NSQIP in general, GV surgery, and orthope­dic surgery (Table 1).



Our QIP proved that installing the Caprini model as a compulsory stratifica­tion method and VTE prevention strategies were effective in reducing VTE in general and vascular surgery patients. Several pa­tient-related factors contributed to the in­cidence of VTE. In addition, major surgery is one of the wellrecognized risk factors for VTE. Despite the presence of recognized evidence-based guidelines by organiza­tions such as the American College of Chest Physicians,compliance worldwide continues to be suboptimal.

The Institute of Medicine has classified the failure to provide appropriate screening and preventive treatment to hospitalized, at-risk patients as a medical error, and the Agency for Healthcare Research and Qual­ity has ranked the provision of such preven­tive treatment as one of the most important things that can be done to improve patient safety.

Our initial poor adherence to perform­ing risk assessment for VTE is not a unique problem to SKMC. In 2008, results from the multinational ENDORSE (Epidemiologic International Day for the Evaluation of Pa­tients at Risk for Venous Thromboembolism in the Acute Hospital Care Setting) trial showed that only two-thirds of at-risk surgi­cal patients and fewer than half of at-risk medical patients received any form of an­tithrombotic prophylaxis.9 In our institute, our initial adherence rate was less than 80% in surgery patients. The initial lack of adher­ence could have been attributed to the lack of awareness of VTE risk and its implications on both patients and health care systems or unreasonable fear of intra- or postoperative bleeding in surgical patients.

The concept of risk assessment is not new. Caprini et al developed a risk assessment tool in 1988 following several similar reports of noncompliance at the time. Stratification was classified into low, moderate, and high risk, which is similar to the risk stratification we are using. Our risk stratification model follows the Caprini score model (Figure 1). We believe that the score generated at the end of the form gives the health care pro­vider immediate feedback on the overall VTE risk of the patient. This score enhances the awareness for VTE further and helps in deciding on which patients need antithrom­botic prophylaxis after discharge.

The goal of our QIP for prevention was to eliminate all episodes of preventable VTE events by improving compliance with antithrombotic prophylaxis guidelines. Our efforts in forming a task force to address our adherence problem and the recom­mendations of our VTE task force are simi­lar to several reports in the literature.10,11 For example, Vyas et al reported an audit on general internal medicine patients after implementing a VTE order set on all admis­sions. Similar to our improvement in adher­ence with VTE risk assessment form, Vyas et al showed that adherence increased from 75% to 91% at 2 months postintervention and to 95% at 1 year.10 Likewise, Novis et al instituted a standardized computerized DVT risk assessment program. Pharmacological antithrombotic prophylaxis increased from 14% to 36%, and use of sequential devices doubled to 40%.

Adherence to performing VTE risk assess­ment was excellent in our study. We believe the hard stops we instituted as well as the education of nursing and house staff and the increased awareness to the problem of VTE helped in improving our adherence more than that seen by others. Our adher­ence rate with performing VTE risk assess­ment has reached 100%, but not all these patients actually received antithrombotic prophylaxis because the physician did the risk assessment but did not follow through in ordering antithrombotic prophylaxis. In an internal audit, we discovered that the adherence with performing the risk assess­ment has greatly improved, and it is done 100% of the time. However, when it comes to ordering VTE prophylactic measures, our compliance is still less than 80%.

Another reason for our excellent adher­ence to performing VTE risk assessment is embedding the VTE risk assessment form in the electronic medical record (EMR). Utiliz­ing the EMR to improve adherence with VTE risk assessment is well described in the liter­ature as well. Kucher et al demonstrated that the implementation of an electronic alert system increased prophylaxis and reduced the incidence of DVT or PE by 41% at 90 days.12 A Cochrane database systematic re­view consolidated similar results for various methods of intervention, including electron­ic alerts and other interventions. The review concluded that interventions with an alert system were most effective. Similarly, Bahl et al and Cassidy et al have shown that VTE risk assessment correlates with probability of VTE and that mandatory prophylaxis and physical ambulation in surgery patients can lower the risk of VTE postoperatively.

Improving physicians’ behaviors in the ac­tual prescription of antithrombotic prophy­laxis whether chemical or mechanical was of equal importance as completion of the compulsory assessment forms. Passive dis­semination of guidelines as a QIP does not ensure actual compliance with prescription rates. Our prescription rates before the com­pulsory form in SKMCwas 76%in 2010 that improved to a 100% in 2013, after institut­ing the compulsory form. Wehave observed that appropriate education for physicians and other healthcare professionals also played an integral role in improving both compliance in assessment and prescription. Similarly, Cohn et al demonstrated an im­provement in appropriate VTE prophylaxis from 43% to 86% at 12 months after insti­tuting an educational program consisting of regular education and repeated audits and assessments.



A compulsory risk assessment for VTE has led to an overall improvement in VTE rates in the entire surgery institute, and our general and vascular rates of VTE have be­come among the best compared to other ACS NSQIP hospitals. The ACS NSQIP and the hospitals participating in the ACS NSQIP are the source of the data used herein. They are not verified and are not responsible for the statistical validity of the data analysis or the conclusions derived by the authors.


Author’s Note

This article was presented as an oral pres­entation at the ACS NSQIP National Confer­ence in San Diego, California, on July 2013.


Declaration of Conflicting Interests

The author(s) declared no potential con­flicts of interest with respect to the research, authorship, and/or publication of this article.



The author(s) received no financial sup­port for the research, authorship, and/or publication of this article.





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