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Bleeding and Transfusion in Acute Coronary Syndromes and Percutaneous Coronary Interventions
oxygen is reduced. Depletion of 2,3-diphosphoglycerate (2,3DPG) is filtration rate (GFR) must be systematically measured for every patient
practically immediate once fresh blood has been collected and stored. and monitored during treatment to guide the choice of drug and dose.
2,3DPG is intimately linked to oxygen affinity and regulates oxygen Renal failure is a major determinant of bleeding complications, with an
transport and delivery at tissue level. Microvascular circulation is exponential increase in risk of bleeding with declining renal function,
impaired by transfused red blood cells, since transfusion induces an particularly for creatinine clearance <60ml/minute or GFR <60ml/
important vasoconstrictive reaction, which could be due to depletion minute/1.73m
2
. As a result, inappropriate dosage or unnecessary
in nitric oxide (NO). Red blood cell deformability observed under prolonging of treatment may lead to an accumulation of the drug in
normal shear stress conditions is altered in preserved blood cells, the organism and thereby to a higher risk of bleeding, even for
thereby impairing microcirculation. moderate renal dysfunction. The selection of drugs known to reduce
the risk of bleeding is necessary to minimise risk of bleeding
Decreased Bleeding Risk Leads to Improved Outcome complications. In summary, the following steps should be taken to
In the Fifth Organization to Assess Strategies in Acute Ischemic address the risk of bleeding:
Syndromes (Oasis-5) study, which compared enoxaparin with a new
anticoagulant, fondaparinux, a 50% risk reduction for bleeding at • evaluation of ischaemic risk, according to the presence or absence
nine days was observed in favour of fondaparinux, leading in turn to a of predictors of bleeding (see Table 1);
significant risk reduction for death at 30 days and six months.
14
Most
of the reduction in the death rate was imputable to the risk reduction • baseline characteristics must be taken into account, particularly
for bleeding. Similarly, in the Harmonizing Outcomes with age, female sex and low bodyweight;
RevascularIzation and Stents (HORIZONS) study, the use of bivalirudin
in the setting of primary PCI for ST-elevation myocardial infarction led • renal function has to be evaluated by calculating creatinine
to a significant risk reduction of bleeding compared with a clearance and/or GFR; and
combination of anticoagulants plus GPIIb/IIIa inhibitors.
20
In this study,
a significant reduction in death at 30 days was observed, probably • previous history of bleeding must be recorded, and recent or
linked to the risk reduction for bleeding. Therefore, the loop is ongoing bleeding must be searched for.
closed: an increased risk of bleeding leads to an increased risk
of death, but a risk reduction for bleeding leads to a risk reduction With these simple measures, the bleeding risk of an individual patient
for death. can be well evaluated and the treatment strategy can be customised
to favour drug associations and duration of therapy that minimise
The paradigm in the treatment of patients suffering from ACS is now
shifting. Prevention of bleeding has become equally important as the
prevention of ischaemic events. Therefore, when dealing with ACS
The paradigm in the treatment of
patients at the time of risk stratification, the risk of bleeding must be
considered in the same way as the risk of ischaemic events. The most patients suffering from acute coronary
appropriate therapeutic strategy should be chosen depending on the
syndromes is now shifting. Prevention
proven capacity of a drug, treatment or procedure to reduce bleeding
risk (see Table 1).
of bleeding has become equally
important as the prevention of
In this regard, the choice of vascular approach is critical. It has been
shown in a meta-analysis that using a radial approach leads to a
ischaemic events.
significant reduction of bleeding complications at the site of vascular
approach.
21
Furthermore, in a large registry involving more than
30,000 patients in Canada, the use of the radial approach was shown bleeding risk. In addition, the need for invasive strategy has to be
to significantly reduce the need for blood transfusion, taken as a evaluated according to the initial ischaemic risk of patient, also taking
surrogate marker for bleeding. The radial approach was also shown to into account co-morbidities and expected beneficial effect in
reduce the risk of death at one year by 17% (odds ratio [OR] 0.83 perspective with the bleeding risk. The appropriate vascular access
[0.71-0.98]; p=0.001 radial versus femoral).
22
route must be chosen, favouring radial access where possible.
Practical Approaches to the Risk of Bleeding Management of Bleeding Complications
The management of ACS or PCI patients should incorporate risk No interruption of active treatments is required in cases of minor
stratification for both ischaemic and bleeding risk. Risk scores exist for bleeding. However, major bleeding such as gastrointestinal bleeding,
the stratification of both risk of death and risk of bleeding, in both retro-peritoneal bleeding, intracranial haemorrhage or severe blood
ACS and PCI. However, clinical judgement is critical to the decision- loss requires the interruption of antiplatelet and anticoagulant
making process. Decisions must be made on a case-by-case basis, treatment, and neutralisation where possible, particularly if bleeding
particularly among more frail patients. This implies that a careful cannot be brought under control by specific interventions. If local
approach has to be taken when selecting drugs and their dosage and treatment is successful in controlling active bleeding, such as
interventions. Since many of the drugs used in the treatment of ACS gastrointestinal bleeding, interruption of anticoagulant and
are eliminated by the renal route, extreme attention has to be paid to antiplatelet therapy is unnecessary. However, the risk of withdrawing
renal function. Creatinine clearance or, preferably, the glomerular antithrombotic and/or antiplatelet agents must be put into perspective
INTERVENTIONAL CARDIOLOGY 87
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