Managing PEs: When anticoagulation is not enough

The Haematology Association of Ireland (HAI) celebrated 25 years with a notable line-up of eminent national and international guest speakers at its 2024 Annual Scientific Meeting, which took place on 11-12 October at the Europa Hotel, Belfast.

Reflecting on the origins of the Association, President of the HAI Prof Paul Browne, Professor of Haematology at Trinity College Dublin, and Consultant Haematologist and Director of the National Adult Stem Cell Transplant Programme at St James’s Hospital, Dublin, warmly welcomed the delegates and said that returning to Northern Ireland was “very appropriate”, as the first inaugural meeting occurred in Antrim in 1999.

The packed event featured an array of medical and scientific oral presentations, research updates, and ‘state-of-the-art’ lectures, as well as a nursing and advanced haematology practitioner programme, a laboratory session programme, and a post-conference educational session for specialist registrars and haematology trainees.

The meeting heard from Dr Karen Breen, Consultant Haematologist, Joint Clinical Director for Haematology, Haemostasis, Cellular Pathology, Oncology, and Haematology Clinical Trials, Guy’s and St Thomas’ NHS Foundation Trust, London, UK, who delivered a practical and evidence-informed overview of recent advances in the management of pulmonary embolism (PE), and shared her experiences of implementing a PE response team (PERT) at Guy’s and St Thomas’.

Dr Breen began by presenting clinical cases to address the complexity of diagnosing and categorising PEs according to the European Society of Cardiology (ESC) classification system. She outlined the deficits in current guidance on how intermediate-risk PE, in particular, is treated. “Massive PE in a way is easy to manage because we know these patients have such a significant risk of mortality that they need to be treated,” she said, noting that the risk of bleeding post-thrombolysis is generally outweighed by the risk of death for this group.

Similarly, “low-risk PE is also relatively straightforward,” she said, explaining that these patients are not haemodynamically compromised and show no signs of hypotension, no signs of right ventricular dysfunction on CTPA (computed tomography pulmonary angiography), and have a normal serum troponin. Generally, this group can be sent home on direct oral anticoagulants and treated via outpatient pathways, the conference heard.

“It’s the sub-massive, or intermediate-risk, patients that we need to think about,” Dr Breen said, describing the significant associated mortality, and “difficult-to-treat” nature, of this cohort, for whom “anticoagulation alone is often not sufficient”. She went on to outline the clinical presentation of patients, including elevated right ventricle to left ventricle ratio, and elevated troponin. She reminded delegates that these patients are not always hypotensive, but have a substantial risk of adverse cardiovascular events and death. “Even extended 30-day mortality is high,” she added.

Dr Breen emphasised that patients with intermediate-risk PE “can become unwell really quickly” and “deteriorate before our eyes” when increased right ventricular pressure ignites what she called the “spiral of doom”. She then moved on to explore the pros and cons of current and emerging reperfusion strategies, including intravenous systemic lysis and novel catheter-based therapies. “There is an increasing indication for ECMO [extracorporeal membrane oxygenation] for patients who need a bridge to become stable for therapy,” Dr Breen said. “Some patients may require surgical embolectomy, although it is quite rare these days.”

Attendees heard that guidelines are conflicting regarding intermediate-risk PE, and that “the evidence is not quite there yet” for newer approaches. Dr Breen presented the available data from the PEITHO study – which found that fibrinolytic therapy did prevent haemodynamic decompensation in intermediate-risk PE, but also increased the risk of major haemorrhage – and the MOPETT study – which demonstrated that a lower dose of thrombolysis was effective, with a lower risk of bleeding.

She also described “a lot of development around catheter-based therapies” in particular. “Catheter-based research is primarily observational and industry sponsored,” Dr Breen said. She outlined the value of “having radiology nearby”, as well as the importance of “discussing individual cases” to achieve best outcomes.

Addressing care disparities, the conference heard that many patients are “at the mercy of their geography”, and Dr Breen advocated that all patients should “at the very least have access to a discussion around whether or not they are suitable candidates for these treatments”.

The ESC guidelines recommended the establishment of PERTs for management of intermediate- and high-risk PE, when resources are available, in view of the positive data generated since the first team was established in 2012. PERTs improve time to PE diagnosis, initiation of therapy time, cost of therapy, and mortality, Dr Breen told delegates. She described the implementation of PERTs across the world, before sharing her own experiences at Guy’s and St Thomas’.

“We are the triage for the PERT,” she said, and talked about aiding in categorising PEs, arranging appropriate referrals and investigations, and assessing bleeding risk for patients before treatment. She stressed the value of multidisciplinary discussion around treatment options, saying “we don’t actually have to use additional therapies”, and that around 41 per cent of patients require no intervention.

Among the “service highlights” Dr Breen shared were an improved time to referral, external referrals from other care centres, improved decision-making, and positive long-term outcomes for patients. She also discussed the risks associated with delayed referral and some of the professional challenges faced by PERT members.

Dr Breen concluded her talk by saying: “I would urge everyone to get the basics right, make sure these patients are assessed appropriately…. There are lots of promising potential reperfusion options, but we need to make sure that patients are selected properly for these devices, and equally there’s an equity of care that patients can at least be discussed. Try to establish PERT services if you have those facilities, or at least have access to a PERT network.”