The Correlation of a D-dimer Testing Protocol With Venous Thromboembolism in Surgical Colorectal Patients

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the use of a D-dimer based protocol to screen for thrombotic events in colorectal surgical patients. This study is unique because of the multistage screening process for DVT's using a standardized D-dimer testing methodology and ultrasound that will take place throughout the preoperative, perioperative, and postoperative processes. The data collected from this screening study will help establish the baseline DVT rates in UTMB's colorectal surgical patients before and after surgery. Additionally, the data from this study can help determine if a D-dimer blood test has predictive value in UTMB's colorectal surgical patient population. This study may also provide preliminary evidence for further research regarding the adjustment of D-dimer cutoff values. Specifically for patient subsets such as surgical colorectal patients with a moderate pretest probability and clinical conditions associated with low test specificity

Detailed Description
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This will be a quantitative prospective cohort study conducted at the University of Texas Medical Branch (UTMB) Galveston and League City campuses. Candidates include subjects who will have elective colorectal surgery at UTMB. This study looks to enroll 100 subjects who meet inclusion criteria. The subjects will undergo screening for DVT using a lower limb bilateral venous duplex and a plasma D-dimer assay no longer than 10 days before their operation. This data will be used to observe the point prevalence of DVT's in preoperative colorectal subjects prior to having colorectal surgery. On the day of surgery, the subject will have a D-dimer test. After the operation, for next 2 days the subjects will have a daily D-dimer test and a lower limb bilateral venous duplex on the second day only. This data will determine the incidence of DVT's that were detected by lower limb bilateral venous duplex on inpatient stay day 2 and possibly indicated by an upward trending D-dimer value during the first 2 days of the inpatient stay. Approximately 2 weeks after surgery, at the postoperative clinic appointment, the subject will have a D-dimer assay and a lower limb bilateral venous duplex. This information will be used to determine the number of DVT events in postoperative colorectal hospitalized subjects that were on the D-dimer monitoring protocol. The D-dimer assay detects the presence of fibrin degradation products, which may indicate a fibrin blood clot in the body.6 A maximum of 5 milliliters of blood will be collected for each D-dimer test. If a DVT is detected by the gold standard method which is a bilateral lower limb duplex during any point of study, the subject will be treated as per standard of care at UTMB by the colorectal surgical team

Official Title
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The Correlation of a D-dimer Testing Protocol With Venous Thromboembolism in Surgical Colorectal Patients

Conditions
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Venous Thromboses, Colorectal Cancer, Diverticular Diseases, Crohn Disease, Ulcerative Colitis, Deep Vein Thrombosis

Intervention / Treatment
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* Diagnostic Test: D-dimer and lower limb venous duplex


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Colorectal cancer requiring surgical intervention-elective a)Benign or Malignant Inflammatory colorectal conditions requiring surgical intervention-elective Diverticulitis Ulcerative Colitis Crohn's Disease Exclusion Criteria: Pregnancy Emergency procedures

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| UTMB's Colorectal Surgical Cohort<br>Subjects who meet the inclusion criteria that will have colorectal surgery at UTMB | Diagnostic Test: D-dimer and lower limb venous duplex<br>* D-dimer blood test- The D-dimer assay detects the presence of fibrin degradation products, which can indicate the breakdown of a fibrin clot Lower Limb Venous Duplex- Using an ultrasound to visually look for a clot<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Observe the point prevalence of DVT's in preoperative colorectal patients at UTMB prior to having colorectal surgery. | The data will be used to discover the prevalence of DVT prior to surgery and to establish DVT baseline rates at UTMB. | 1 year | 
| Determine the incidence of postoperative DVT that occurred during the first 2 days of the inpatient stay that was discovered by a lower limb venous duplex | Subjects will have a venous duplex on day two after surgery to look for a DVT | 1 year | 
| Compare the number of DVT events in postoperative hospitalized patients that were on the D-dimer monitoring protocol. | The data will be used to determine the number of DVT's that were discovered in the subject population and to establish baseline rates of DVT after surgery and hospital discharge | 1 year | 
| Determine if there is a statistical difference between the D-dimer value of patients with DVT prior to surgery compared to patients who develop DVT after surgery | This data will be used to compare the D-dimer values in subjects that had DVT prior to surgery to those who developed a postoperative DVT while inpatient or at the postoperative clinic appointment | 1 year | 
| Compare the D-dimer results of DVT positive subjects to DVT negative subjects to identify a specific result range seen in the DVT positive subjects. | These results will be used as preliminary evidence for future research to determine if revised D-dimer cut off values can be diagnostic in conditions known to have low test specificity | 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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D-dimer, Colorectal Surgery, Thrombosis, DVT