Did you know that in the United States alone 400,000 blood clot events occur in patients recently discharged from the hospital? And that blood clots are the most common cause of preventable hospital deaths?

Researchers are investigating this problem and trying to find a solution. The most recent trial conducted was the MARINER trial, whose results were just released in August at the European Society of Cardiology Congress.


The MARINER trial was a randomized, double-blind study that examined the safety and efficacy of rivaroxaban in preventing venous thromboembolism (VTE or blood clot) events and VTE-related deaths in medically ill patients after they were discharged from the hospital.

“The MARINER trial’s aim was to optimize the thromboprophylaxis in medically ill patients with the specific aim of reducing venous thrombosis,” explained Dr. Ebrahim Barkoudah, Associate Director of Hospital Medicine Unit at Brigham and Women’s Hospital.

In the trial, 12,024 medically ill patients were randomized to either receive 10 mg of rivaroxaban once daily, or a placebo. These patients took the medication or the placebo for 45 days. The primary efficacy outcome was symptomatic VTE or VTE-related death, and the principal safety outcome was major bleeding.

Out of the 12,024 patients in the trial, 50 of the 6,007 patients on rivaroxaban and 66 of the 6,012 patients on the placebo experienced symptomatic VTE or VTE-related death. In relation to major bleeding, 12 out of 5982 patients on rivaroxaban experienced major bleeding and 9 out of 5,980 patients in the placebo group experienced major bleeding.

The trial results were considered neutral. The investigators on the study concluded, “Rivaroxaban was not associated with a significant lower risk of symptomatic venous thromboembolism and death due to venous thromboembolism than placebo. The incidence of major bleeding was low.”

According to Dr. Barkoudah, MARINER suggests that rivaroxaban should not be prescribed to medically ill patients in general until researchers examine the evidence further. Secondary endpoints show that certain groups of patients—those with heart failure, for instance—might benefit more from extended VTE thromboprophylaxis, but additional examination and studies will be needed to confirm these results.

Recognizing Risk

While the trial results may not be immediately revolutionizing how patients will be treated, the MARINER trial does emphasize the risk that patients face while in the hospital and post-discharge.

“This trial added to our knowledge and shed light on how we look at the risk,” explained Dr. Barkoudah, emphasizing the importance of hospitalists recognizing the risk of VTE after hospital discharge. “Hospitalists do not see the risk in their patient community because they are discharging the patient, but the risk is out there. The patient leaves with the risk.”

“We need to do more to prevent this,” Dr. Barkoudah stressed. “We can do a better job to make sure that these VTEs are prevented.”

Part of the risk comes from patients being immobile in the hospital and after discharge, when they are no longer being motivated to move by a treatment team. By raising awareness around this issue, patients can be empowered to make sure they are getting the care they need to avoid a blood clot.

“The risk for each patient is individual. I would encourage every patient to start a discussion with their healthcare providers,” said Dr. Barkoudah. “The ultimate cure is for everyone to move. Please, if you can get out of bed safely, with the help of physical therapy or the help of a treatment team, do it and do it as soon as possible.”

What can Patients do?

If you are a patient spending time in the hospital, talk to your doctor about your risk of developing a blood clot.

If you have a history of blood clots, it’s important that your healthcare team knows about your medical history and any medications you may be taking, including anticoagulants. Once your healthcare provider knows about your history, there are precautions to help protect you from developing a new blood clot.

Being in the hospital is a scary and stressful time, but knowing the right questions to ask can make all the difference.