Research findings suggest that unseen sources of significant blood loss may pose the greatest risk.
Time is of the essence to administer the best possible treatment when a patient enters the hospital with a heart attack. In the case of patients with ST-elevation myocardial infarction (STEMI) — one of the most dangerous and potentially deadly forms of heart attack — the coronary artery is completely blocked, restricting life-giving blood from flowing through the arteries to the heart muscle.
“When a patient arrives at the emergency department with STEMI, it is a race against time to open up the artery and get blood flowing again,” explains cardiologist and Vancouver Coastal Health Research Institute researcher Dr. Graham Wong.
Patients with STEMI are often treated with an emergency procedure called primary percutaneous coronary intervention (pPCI) to open up the blockage. This is a non-surgical approach in which clinicians thread a flexible, long and hollow tube through an artery in the patient’s groin or arm. The tube is mounted with a small balloon that is inflated in the blockage to expand the artery and restore blood flow. A small metal stent is then usually inserted to ‘scaffold’ the artery open.
A leading potential negative consequence of pPCI is major bleeding: when patients may require blood transfusions and/or another urgent procedure to stop blood loss and replenish depleted blood stores.
Access-site major bleeding can occur at the incision point for the balloon-mounted tube. Non-access-site major bleeding can be located anywhere else in a patient’s body. This is largely due to either medications used during treatment or other factors, such as comorbidities, a patients’ age and a drop in hemoglobin — a protein found in red blood cells — that can starve the organs of oxygenated blood.
“With any intervention that is used to treat a blocked artery that caused a heart attack, you need to use powerful blood thinners, which can also lead to problems such as major bleeding,” adds Wong.
Non-access-site major bleeding shown to be the greater risk factor
Among STEMI patients, major bleeding prevention is not only important for stopping excess blood loss, it can also decrease the risk of short- and long-term consequences such as heart attack, stroke or even death.
“Any major bleeding experienced by heart attack patients has the potential to lead to poorer outcomes.”
Wong’s research study, published in CJC Open, the journal of the Canadian Cardiovascular Society, examined in-hospital access-site and non-access-site major bleeding among 1,494 STEMI patients who received pPCI between 2012 and 2018.
He found that 121 patients (8.1 per cent) experienced major bleeding. Among these, 87 had major bleeding away from the incision site and 34 experienced it where the stent tube was inserted. While 23 patients passed away as a result of non-access-site major bleeding, only two passed away from access-site major bleeding.
“Previously, a lot of attention has been paid to access-site major bleeding, and I think our research has shown that non-access-site major bleeding is just as important, and may even be more important with respect to outcomes.”
Similarly, cardiac arrest — when the heart stops beating after not receiving oxygenated blood for a prolonged period of time — was more associated with non-access-site major bleeding than access-site major bleeding (23 patients versus one) and stroke (12 patients versus one).
Around one third of patients bled from the stomach, which Wong says may indicate the need for further research into how to prevent gastrointestinal bleeding among STEMI patients.
“Our findings are a clear indicator that non-access-site bleeding produced worse in-hospital outcomes, which could mean that we need to develop new approaches to prevent these bleeds.”