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
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