High Bleeding Risk in Acute MI: Impact on Treatment and Need for Further Research
Nearly one-third of patients experiencing an acute myocardial infarction (MI), commonly known as a heart attack, are identified as being at high bleeding risk (HBR). New data reveals that these patients, regardless of whether they receive percutaneous coronary intervention (PCI) or are managed with medication alone, face significantly higher rates of both major adverse cardiac events (MACE) and major bleeding over time. This highlights a critical need to broaden the assessment of bleeding risk beyond those undergoing PCI and to generate more evidence-based strategies for this vulnerable population.
Understanding High Bleeding Risk
The Academic Research Consortium (ARC)-HBR criteria, introduced in 2019, assess bleeding risk using 20 clinical variables. These criteria, while initially focused on PCI patients, are increasingly recognized as overlapping with indicators of frailty and systemic vulnerability. Recent research, analyzing data from England, Wales and Sweden, demonstrates that 39% of patients with acute MI meet ARC-HBR criteria.
Registry Data: MINAP and SWEDEHEART
Researchers analyzed data from 563,251 patients with acute MI in England and Wales (MINAP registry) and 189,102 patients in Sweden (SWEDEHEART registry) between 2005 and 2019. The findings consistently showed that HBR patients were, on average, older than those without high bleeding risk – with a signify age of 81 years in the MINAP registry and 80 years in the SWEDEHEART registry, compared to 63 and 66 years respectively (P <. 0.001 for both). HBR patients also tended to have a lower body mass index and were less likely to present with STEMI (P < 0.001 for all).
Increased Risks for HBR Patients
The analysis revealed a substantially increased risk of both MACE and major bleeding for HBR patients, irrespective of their treatment strategy – whether they underwent PCI or received medical management. Specifically, adjusted hazard ratios showed:
- MACE: 2.99 (95% CI 2.95-3.02) in MINAP; 2.68 (95% CI 2.64-2.73) in SWEDEHEART
- Major Bleeding: 2.28 (95% CI 2.21-2.35) in MINAP; 2.71 (95% CI 2.58-2.85) in SWEDEHEART
Patients managed medically were more likely to be older than 75, and have conditions like cancer, anemia, or moderate/severe chronic kidney disease (CKD) compared to those treated invasively.
The Role of Revascularization and Antiplatelet Therapy
Experts suggest that clinicians should proactively evaluate why HBR patients are not undergoing revascularization procedures. Questions arise regarding potential biases and whether a more conservative approach is being taken due to perceived higher risks. There is also a lack of data regarding optimal antiplatelet therapy strategies for non-revascularized patients.
Current research, such as the MASTER DAPT trial, indicates that a short course of dual antiplatelet therapy (DAPT) can reduce the risk of recurrent events in HBR patients undergoing PCI. However, it is unclear whether similar benefits would be observed in medically managed HBR patients. Findings suggest that continuing DAPT for longer than one month in HBR patients may actually be harmful.
Future Directions and the Need for More Research
The current findings underscore the need for more research specifically focused on HBR patients, both those undergoing PCI and those managed medically. Larger studies are required to determine the optimal duration of DAPT and to identify strategies to improve outcomes in this high-risk population. A broader consideration of bleeding risk, encompassing both invasive and conservative treatment approaches, is crucial for providing individualized and evidence-based care to all patients with acute MI.