Screening for occult lower-extremity deep vein thrombosis on admission to acute inpatient rehabilitation: A cross sectional, prospective study

Leila Ettefagh; Mairin A Jerome; Joseph Porter; Hassan H Monfared; David T Burke

doi:10.4103/jisprm.jisprm_42_19

ORIGINAL ARTICLE

Year : 2019 | Volume : 2 | Issue : 3 | Page : 110-113

Screening for occult lower-extremity deep vein thrombosis on admission to acute inpatient rehabilitation: A cross sectional, prospective study

Leila Ettefagh¹, Mairin A Jerome¹, Joseph Porter¹, Hassan H Monfared², David T Burke¹
¹ Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA
² Department of Rehabilitation Medicine; Department of Orthopedics, Emory University, Atlanta, GA, USA

Date of Submission	24-Jan-2019
Date of Decision	20-Feb-2019
Date of Acceptance	28-Feb-2019
Date of Web Publication	12-Jul-2019

Correspondence Address:
Prof. Hassan H Monfared
Emory University School of Medicine, Atlanta, Georgia
USA

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jisprm.jisprm_42_19

Abstract

Introduction and Background: Early detection and treatment of deep venous thrombosis (DVT) can decrease the morbidity of postthrombotic syndrome as well as the mortality and morbidity resulting from pulmonary embolism. Despite this risk, it is not the standard of care to screen patients for DVT on admission to an inpatient rehabilitation facility (IRF). There are few studies examining the prevalence of occult DVT on admission to acute IRF and the effect of this screening. Guidelines for the prophylaxis of hospitalized patients have informed patient's care for years. Recently, however, the patient population in the inpatient rehabilitation hospitals has changed, and new prophylactic medications have been introduced. Given these changes, the study reviewed the frequency of lower-extremity DVT among consecutive patients admitted to a university-based freestanding rehabilitation facility. Materials and Methods: This pilot, prospective observational cross-sectional study was designed to better understand the prevalence of occult DVT among patients admitted to a freestanding IRF and to identify associated clinical factors. All consecutive patients admitted to our university-based IRF between October and December 2017, excluding those with a preexisting DVT diagnosis or the inability to undergo lower-extremity ultrasound, were consented. All patients were assessed with a bilateral duplex ultrasound of the lower extremities within 72 h of admission. Results: Of 98 patients screened, 47 (48.0%) were male and 51 (53.1%) were female, with a mean age of 61.4 (±14.2) years. The most common admission diagnoses were ischemic stroke (23.5%), debility/medical complexity (22.4%), and hemorrhagic stroke (11.2%). One patient was positive for a lower-extremity DVT on admission screening duplex ultrasound, yielding an incidence of 1.02%. Conclusions: Our study suggests that DVT screening by duplex ultrasound for all patients admitted to an acute IRF does not seem clinically warranted.

Keywords: Deep venous thrombosis, inpatient rehabilitation facility, screening

How to cite this article:
Ettefagh L, Jerome MA, Porter J, Monfared HH, Burke DT. Screening for occult lower-extremity deep vein thrombosis on admission to acute inpatient rehabilitation: A cross sectional, prospective study. J Int Soc Phys Rehabil Med 2019;2:110-3

How to cite this URL:
Ettefagh L, Jerome MA, Porter J, Monfared HH, Burke DT. Screening for occult lower-extremity deep vein thrombosis on admission to acute inpatient rehabilitation: A cross sectional, prospective study. J Int Soc Phys Rehabil Med [serial online] 2019 [cited 2023 May 28];2:110-3. Available from: https://www.jisprm.org/text.asp?2019/2/3/110/262681

*Leila Ettefagh and Mairin A. Jerome equally contributed to this work.

Introduction

Venous thromboembolism (VTE), such as deep venous thrombosis (DVT) and pulmonary embolism (PE), is a major health-care problem, resulting in significant mortality, morbidity, and expenditure of resources. Well-established risk factors for DVT include immobility, trauma, smoking, increased body mass index (BMI), and malignancy, as well as many other clinical characteristics.^[1],[2],[3] The previous studies showed a prevalence of DVT between 0.6% and 30% among patients with VTE risk factors. Much of the published literature suggests a high incidence of VTE for patients who are more critically ill and who have longer hospital lengths of stay.^{[4],[5],[6],[7],[8],[9],[10],[11],[12],[13]} The total incidence and prevalence of VTE remains elusive, which is likely due to the silent nature of this disease.^[14] Cook et al. demonstrated a comparative incidence of DVT in critically ill patients, with a 9.6% rate of DVT over the intensive care unit stays, despite standard of care chemoprophylaxis or mechanical prophylaxis.^[11] Cifu et al. reported an incidence of occult DVT of 11% among patients admitted to an inpatient rehabilitation facility (IRF) with a diagnosis of brain injury, with incidences of 18% for traumatic brain injury and 4% for nontraumatic brain injury.^[12] Yablon et al. reviewing IRF patients with brain trauma found the varied prevalence of DVT among those admitted to an IRF with brain pathology, including 21.2% among those with brain tumors, 16% among those with intracranial hemorrhage, and 6.7% among those with traumatic brain injury (6.7%).^[13]

However, as a group, diagnostic profiles of patients admitted to acute rehabilitation hospital have changed over time. Reviewing Medicare data, the percentage of patients diagnosed with stroke admitted to a rehabilitation hospital was 16.6% in 2004 and 19.4% in 2014. Other neurologic conditions accounted for 5.2% in 2004 and 13.1% in 2014. Other conditions have had a reduced population in the inpatient rehabilitation with joint replacements of the lower extremity accounting for 24.1% in 2004 and 7.8% in 2014. During this period, medication options for VTE prophylaxis have expanded to include factor Xa inhibitors as well as direct thrombin inhibitors. Therefore, both the patients and the treatment options have changed over the past decade. It is not clear, however, how this may affect the prevalence of DVT on admission to a rehabilitation hospital.^[10] Venous ultrasonography has clinical utility as a screening tool for DVT, with a sensitivity of 88%–98% and specificity of 97%–100% with a combined sensitivity of 98% for proximal venous thrombosis.^[15],[16] It is portable, noninvasive, and easy to use. We, therefore, used Doppler ultrasonography of consecutive admissions to a freestanding IRF, including all admission diagnoses, to determine the prevalence of occult lower-extremity DVT on admission and determine its potential value as a standard of care practice.

Materials and Methods

This prospective, cross-sectional pilot study invited all patients who were admitted between October and December 2017 to a freestanding university-based IRF to participate in the study. The project was reviewed and approved by the Emory University Institutional Review Board in accordance with the Declaration of the World Medical Association with ID number IRB00095304. Informed consent was obtained by physicians from all patients or a legally authorized representative. Patients were informed they would not incur a cost for the screening duplex. It was also explained that if further treatment was recommended due to positive results of the test, it would become part of their medical treatment and submitted to their insurance. Patients with positive DVT were treated per current standard of care. In the event there was clinical concern for DVT concurrent with an inability to obtain an immediate ultrasound per study protocol, a more emergent Doppler could be ordered per hospital's standard orders. When ordered due to emergent clinical concern, the patients' insurance providers would be charged per usual medical care. All collected data were deidentified and stored in a Microsoft Excel database.

Patients with known DVT diagnosis within the previous 6 months were excluded from the study. Compression ultrasonography was performed on all patients meeting criteria who provided informed consent. A licensed ultrasound technician performed the duplex scans 3 days/week, with all patients scanned within 72 h of admission. Per protocol, the technician was to alert the study team at the time of ultrasound if there was a concern for positive DVT, so as to not delay necessary treatment. A contracted cardiologist trained in readings of lower-extremity Doppler ultrasonography interpreted the studies and results were entered into the patients' medical records.

The primary outcome measure of this study was the presence of a previously undiagnosed lower-extremity DVT within 72 h of admission. Secondary outcome measures included any clinical factors associated with an increased risk of DVT, such as age, gender, BMI, admission diagnosis, presence of active malignancy, history of recent mechanical ventilation, surgeries, trauma, lower-extremity fractures, methods of DVT prophylaxis, and prior hospital length of stay.

Results

Among 127 patients admitted between October and December 2017, 7 (5.5%) were excluded due to prior active DVT and 21 (16.5%) declined to participate. Lower-extremity duplex ultrasound was performed on 99 patients. One patient was excluded due to an inconclusive study without the opportunity for follow-up. Of the 98 remaining patients, 47 (48.0%) were male, 51 (53.1%) were female, and the mean age was 61.4 years (±14.2). At the time of the scan, the average hospital length of stay had been 16.4 days (±14.6). Thirty patients (30.6%) received prior mechanical ventilation, 9 patients (9.2%) suffered multiple traumas, 6 patients (6.1%) had lower-extremity fractures, and 15 patients (15.3%) had an active diagnosis of cancer. Methods of prior anticoagulation prophylaxis most commonly included subcutaneous prophylactic-dose enoxaparin or heparin injections (72.4%), full-dose anticoagulation (13.3%), mechanical prophylaxis (12.2%), and aspirin (1%). Admission diagnoses included ischemic stroke (23.5%), debility/medical complexity (22.4%), hemorrhagic stroke (11.2%), other neurological disorders (9.1%), amputation (8.2%), spinal surgery (8.2%), recent organ transplant (7.1%), multiple trauma (5.1%), brain surgery (2%), nontraumatic spinal cord injury (2%), and traumatic spinal cord injury (1%). The category of “other neurological disorders” included seizure, acute inflammatory demyelinating polyradiculoneuropathy, and multiple sclerosis exacerbation. [Table 1] shows further data on our patients with the five major rehabilitation admission diagnoses.

Table 1: Patient characteristics of the five major admission diagnosis

Click here to view

Of 98 screened patients, 1 (1.02%) had a positive duplex ultrasound, indicative of a lower-extremity DVT. This patient presented on admission with unilateral lower-extremity swelling and calf tenderness. This patient had a spinal cord injury secondary to rhabdomyosarcoma with metastasis to the spine and was on chemoprophylaxis with enoxaparin at prior hospitalization. With only one DVT, statistical analysis was hampered by a lack of power.

Discussion

As per recent studies, the number of patients admitted to rehabilitation hospitals is increasing due to changes in insurance company policies, increasing awareness of both patients and medical staff about the benefits of rehabilitation, improvements in rehabilitation services, and an increased number of elderly patients who require postacute care.^{[1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17]} Most patients admitted to an IRF are transferred from an acute care setting, many with multiple VTE risk factors, affecting both acute and postacute care.

Diagnostic categories, prevention methods, and management protocols have changed dramatically over the past 10 years. Therefore, data on previous patients' population can change the prevalence and incidence of DVT seen on admissions to an IRF and may need to be updated to determine whether more vigilant surveillance might be needed.^[10] This study was undertaken to see if all these have changed the incidence of VTE on admission.

This study of consecutive patients admitted to an inpatient IRF revealed a prevalence of previously undiagnosed DVT to be 1.02%. Adding these findings to assessments made in the acute care facilities, the prevalence of DVT at the time of our study was 6.3%. These findings are similar to those found among similar populations but much lower than those reported by studies of IRF admissions of limited diagnoses.^{[12],[13],[18],[19]} Our findings may be indicative of better screening and more thorough prophylaxis at the acute care hospitals. As it was shown in previous studies, thromboprophylaxis decreases the incidence of VTE in hospitalized patients,^{[20],[21],[22]} although not eliminating the total VTE risk and its related mortality rates.

It is noteworthy that the patient who was positive in our study did have signs and symptoms of a DVT that were evident at the time of our admission assessment, and duplex ultrasound for lower extremities DVT evaluation would have been performed regardless. The lower-extremity swelling and calf tenderness were not described in the acute hospital medical records and therefore may have been newly developed. Bendayan and Boccalon reported that physical examinations alone is not cost-effective and cannot replace noninvasive screening methods to screen occult DVT.^[23] Based on the previous studies, duplex ultrasound can increase the chance of DVT diagnosis but such utilization requires the guidance of a good history and physical examination in order to be cost-effective.^[24] In regard to DVT risk stratification and screening cost-effectiveness, Meythaler et al. and Wilson and Murray demonstrated that DVT screening with Doppler ultrasound on brain injury patients had been more cost-effective compared to other patients including stroke patients.^[25],[26] Pini and Spyropoulos reported that prior hospitalization (52%), cancer (48%), and surgery (42%) are the most common VTE risk factors.^[27] Yumoto et al. reported that a higher injury severity score and the presence of lower-extremity fractures were the two most frequently reported significant VTE-related risk factors among the severely injured patients presented to a single-center intensive care unit.^[18] Alper et al. categorized the patients into low and high risk for DVT based on the previous DVT, presence of active cancer, hospitalization more than 6 days, and age above 46 years. The incidence of lower-extremity DVT among high-risk patients was found to be 21% compared to 5.2% in low-risk patients. Their model demonstrated a 98.1% sensitivity for predicting DVT, which can be a very useful model to better risk stratify patients with suspected DVT.^[19]

In summary, literature shows that appropriate method of thromboprophylaxis, thorough history, and physical examinations accompanying with screening of patients with the highest risk of VTE are the most cost-effective methods for an early detection of occult DVT and preventing DVT-related morbidity and mortality.^{[18],[19],[20],[21],[22],[23],[24],[25],[26],[27]}

Study limitations

Nearly 17% of the patient population declined to participate, potentially altering the incidence of DVT. Second, as this was a small pilot study from a single academic center, one might anticipate that findings might differ, where other such centers in diverse geographic and economic regions as well as nonacademic IRF centers might attract different populations and produce different findings.

Conclusions

Our study suggests that DVT screening for all patients admitted to acute inpatient rehabilitation may not be clinically warranted. We did not find a significant number of patients with previously undiagnosed DVT through our screening process. However, to conclusively make such a recommendation, a study with a larger population and more complete patient enrollment is warranted. Further, research studies are recommended to define patients at the highest risk of VTE and to consider a time-based DVT screening during their acute inpatient rehabilitation stay.

Financial support and sponsorship

The project received support and funding through department of Rehabilitation Medicine, Emory University School of Medicine.

Conflicts of interest

There are no conflicts of interest.

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