Bleeding Avoidance Strategies
Peri-procedural major bleeding complications independently predict higher mortality and poorer outcomes. The importance of avoiding such complications is increasingly apparent and strategies to achieve this need to be a fundamental part interventional practice. The radial artery should be the preferred access route for PCI to avoid access site-related bleeding events although there may be circumstances, where this may not be possible or femoral devices, such as intra-aortic balloon pumps, may be required. There is evidence that the change in practice from femoral to radial access has influenced outcome. Analysis of the UK national PCI database, comparing primary PCI outcome for STEMI, demonstrated significantly fewer access-site related bleeding complications via the radial approach, which was independently associated with a 30 % reduction in 30-day mortality whose magnitude was similar to that observed following a move from thrombolysis to primary PCI in the management of STEMI.37 Similarly, a meta-analysis of randomised controlled trials of STEMI patients receiving primary PCI demonstrates a reduction in mortality and MACEs, driven by a reduction in major bleeding in patients who had their procedure via the radial rather than femoral route.38
The magnitude of the mortality benefit seen by pursuing a default radial strategy is related to the baseline bleeding risk of an individual patient.39 Patients with the highest risk of bleeding, assessed in this way, gained most from a transradial route for their PCI, with a greater mortality benefit than those at a lower risk of bleeding. Paradoxically, perhaps, patients assessed as having a higher risk of bleeding were unfortunately less likely to receive a transradial PCI in this retrospective study.
Adjuvant pharmacological agents also help determine the likelihood of major bleeding following PCI and therefore outcome. GPIs are potent antiplatelet agents effective in improving ischaemia-related outcomes in PCI,40–42 measured as reduction of a composite clinical end point (death, reinfarction or repeat revascularisation) at the price of an increased risk of major haemorrhage. An initial rise in popularity, due to this evidence, has been followed by a fall in GPI use due to their cost, the bleeding complications and data, such as the HORIZONS-AMI trial.12 HORIZONS-AMI demonstrated less major bleeding and a mortality benefit for using bivalirudin (a direct thrombin inhibitor) versus heparin and GPI. More recently, the HEAT trial43 did not show a mortality benefit or reduced major bleeding for bivalirudin and, indeed, unfractionated heparin alone had a comparable outcome to bivalirudin. The HEAT trial employed much more contemporary practice than HORIZONSAMI; well deployed, third-generation drug-eluting stents were used via a radial approach (80 %), with high use (90 %) of newer P2Y12 agents (prasugrel and ticagrelor). The newer P2Y12 agents also improve outcomes following the percutaneous treatment of acute coronary syndrome (ACS) compared with clopidogrel, at the expense of increased bleeding risk.44,45 Fondaparinux given instead of enoxaparin to ACS patients reduces major bleeding and improves long-term mortality.46
We should tailor our procedural practices and pharmacological therapies used in PCI procedures undertaken on an individual patient basis, balancing risk of ischaemia or failure of the procedure with the risk of bleeding. Pre-procedural assessment of a patient’s bleeding risk should be part of our routine assessment of a patient. Analysis of over a million PCIs recorded in the US CathPCI registry was used to develop and validate a PCI bleeding risk prediction score and simplified bedside tool. Entering only 10 variables, such as age, sex, body mass index (BMI), renal function and pre-procedural haemoglobin level, yields a score and a percentage bleeding risk on which a clinician can act.47 Other bleeding risk scores have also been developed to predict non-CABG–related TIMI major bleeding in patients undergoing PCI in the elective and acute setting, such as the Mehran score, through a patient-level pooled analysis of the REPLACE-2, ACUITY and HORIZONS-AMI trials.21 The risk score consists of seven variables: serum creatinine level, age, sex, presentation, white blood cell count, cigarette smoking and anticoagulant agent use. While many of these scores may identify patients at risk of bleeding complications the requirement of laboratory results such as creatinine, haemoglobin levels and white blood cell count for their calculation means that they cannot be used in the highest-risk patients, such as primary, PCI or other emergent cases where such lab results may not be available at the time of the PCI. Nevertheless, a high bleeding risk score should encourage bleeding avoidance strategies, such as a transradial approach and avoidance of high bleeding risk pharmacological agents, such as GPIs. Similarly, if the femoral route is required for arterial access, care should be taken using micro-puncture techniques and ultrasound guidance and vascular closure devices considered.48