D-dimer

Superficial vein thrombosis (SVT) occurs when blood in a vein directly under the skin clots. SVT causes vein tenderness, pain, and skin discolouration. Over time, the vein hardens into a firm, nontender, easily palpable lump. SVT commonly occurs in the veins of the leg. Each year, 1 per 1000 people over the age of 18 have a superficial vein thrombosis (SVT). SVT is painful but usually gets better within a month. Four in 100 people with SVT develop progressively worse blood clotting involving the deep veins or lungs. If a deep vein clot in the leg occurs it can cause permanent disability with post-thrombotic syndrome (long-term leg pain and swelling) and reduced quality of life. If a pulmonary embolism occurs it may causes chest pain, breathlessness, pulmonary hypertension, psychological distress, and potentially death. Risk factors for SVT include varicose veins, pregnancy, cancer, the use of intravenous catheters, a history of venous thromboembolism, age, and thrombophilia. Guidelines tell doctors to use ultrasound scanning to decide whether SVT needs treatment with a blood thinner or not. Blood thinners prevent the clot from worsening. Many people who have SVT go to the emergency department. Scanning is limited to the daytime so often people have multiple trips to the emergency department for their scan and they spend many hours waiting for a doctor to see them. Our research group developed simple ways to limit the need for scans for other types of blood clots, like blood clots in the lungs or in the deep veins. We use a simple blood test called D-dimer. We believe we may be able to use D-dimer to help limit the need for SVT scanning. This is an exploratory study to document what happens to patients tested for SVT in the emergency department, and to see if the D-dimer blood test might be useful in reducing scans. We will review the emergency department charts for patients who came to the emergency department with SVT. Our results will tell us whether further studies would be helpful.

It is important to diagnose pulmonary embolism in a timely manner to prevent death and long-term disability. More than half a million people (4-5% of emergency department patients) are tested for pulmonary embolism, although the positive rate is low. Imaging for PE testing exposes patients to radiation, is expensive, adds time to the emergency visit, and can lead to a false positive diagnoses. Existing protocols aimed at reducing unnecessary pulmonary embolism imaging are complex and seldom used by emergency physicians. Too many patients undergo unnecessary pulmonary embolism imaging. A new tool (called Adjust-Unlikely) could safely reduce pulmonary embolism imaging in Canada. A research group composed of researchers, emergency physicians, and patients developed the Adjust-Unlikely clinical decision rule: a rule which has been customized for emergency physicians and emergency patients. Adjust-Unlikely is highly sensitive at the bedside, meaning there are very few false negative results. The study aim is to prospectively validate Adjust-Unlikely pulmonary embolism testing in emergency patients with suspected pulmonary embolism.

This observational study aims to investigate the association between elevated plasma D-dimer levels and the inflammatory response, as well as its impact on survival in adult patients with community-acquired pneumonia. the study participants will be subjected to sampling for D-dimer and calculation of CURB-65 score. this aims to find the relation between them

INVISIBLE-1 aims to prospectively follow patients up to one year after ischemic stroke to: 1. Determine the cumulative incidence of occult cancer in patients with embolic stroke of undetermined source (ESUS) and elevated D-dimer 2. Describe occult cancer characteristics and spontaneous course of occult cancer Methodology The investigators will include 370 stroke patients with elevated D-dimer (≥ 820 μg/L) at the time of stroke, suspicion of ESUS after initial workup and without known cancer. The investigators will perform a follow-up telephone interview at one year to assess the occurrence of a new cancer and characterize the course of the disease. Significance Determining the real incidence of occult cancer in high-risk patients will help support the implementation of screening trials in the future. Faster detection and treatment of occult cancers would significantly impact patient' outcomes by offering faster cancer treatment and optimal secondary stroke prevention.