Sluggish blood flow in a poorly functioning heart is associated with the development of blood clots which break away, and block blood vessels in the brain causing strokes. Medications that reduce the chances of clot formation (anticoagulants) can improve the health and life expectancy of heart failure patients. Since 2006, NICE treatment guidelines have recommended anticoagulant treatment for patients diagnosed with heart failure who have an irregular heartbeat (atrialfibrillation) which increases the likelihood of blood clots forming even further.
The problem is that they are also associated with significant bleeding risks in the stomach and brain. Currently, there are two different classes of anticoagulant commonly used. Warfarin, an old, inexpensive drug that requires close monitoring to ensure the dose is neither too high, which causes bleeding, or too low which allows clots to form. More recently, a newer alternative group known as novel, or non-vitamin K, oral anticoagulants (NOACs) has emerged.These require virtually no monitoring but unlike warfarin they are not easily reversible if bleeding occurs. They are also considerably more expensive.
Previous studies have shown that the use of anticoagulants in heart failure patients with atrial fibrillation reduces the risk of ischemic stroke and death. Importantly, in many cases the benefit of anticoagulation outweighs the risk of bleeding.
However, heart failure patients have an increased rate of clot related conditions even in the absence of atrial fibrillation. Despite this, previous trials have failed to produce evidence which supports the use of anticoagulants in these patients as the reduction in the risk of stroke was outweighed by a substantially increased risk of bleeding.
But what is happening in the real world of clinical practice?
Sensyne Health has undertaken an analysis to study the role of anticoagulation in heart failure patients. using routinely collected data from its partner NHS Trusts, to answer two key questions:
- Should all heart failure patients discharged from secondary care be prescribed long-term anticoagulants, regardless of the presence of atrial fibrillation?
- Do the newer anticoagulant drugs offer advantages over the older but still widely used drug Warfarin?
The Discovery Sciences team has used statistical methods to analyse ethically sourced de-identified and anonymised heart failure data from Sensyne’s partner NHS Trusts. Heart failure patients with no record of anti-coagulants prescription (the ‘control arm’) were compared to patients prescribed either warfarin or non-vitamin K oral anticoagulants (NOACs). This rapid, preliminary analysis suggests promising survival benefits for heart failure patients on anticoagulants and that the NOACs offer a further survival benefit above warfarin. Furthermore, the data indicate there may be clinically relevant differences between the newer agents.
This work is proof that Sensyne’s approach allows rapid, meaningful analysis of therapeutic efficacy outside the limited confines of strict, randomised clinical trials in a way that reflects the reality of routine clinical practice. This analytical approach offers the prospect of new insights and significant, iterative improvements in healthcare.