Download Integrated care pathways for acute stroke More questions than

Letters to the Editor
Integrated care pathways for acute stroke
SIR—I read with interest the article ‘Integrated care pathways for acute stroke’ [1]. We use a care pathway in our
Acute Stroke Assessment Area. Our audit showed the same
benefits. We also found that it improved the interdisciplinary working and a source to identify the lack of resource.
The difficulty is the time, supervision and training needed to
keep the process efficient.
KRISHNAMURTHY GANESHRAM
Countess of Chester Hospital,
Chester CH2 1UL, UK
Email: [email protected]
1. Kwan J, Hand P, Dennis M, Sandercock P. Effects of introducing an integrated care pathway an acute stroke unit. Age
Ageing 2004; 33: 362–7.
doi:10.1093/ageing/afh225
More questions than answers for stroke
prevention in the elderly with AF
SIR—Dr Morgan demonstrates well in her article ‘Between
the devil and the deep blue sea’ [1] that there is a clear association between atrial fibrillation (AF) and stroke and that
the prevalence of AF increases with age. She reviews the
randomised trials and meta-analysis which have demonstrated the efficacy of thromboprophylactic therapy and the
superiority of coumarin-derived anticoagulants such as warfarin compared with aspirin. However, her review also
raises all the problems which carers of the elderly have in
interpreting this information. Many of the studies excluded
the very old.
One study, SPAF II, did have a cohort of 385 patients
over the age of 75, but unfortunately the warfarin control
was based on the prothrombin time rather than the INR
although the results were translated into INR. The prothrombin time takes no account of the characteristics of the
thromboplastin used to measure the prothrombin time.
Two patients in two different hospitals can have the same
prothrombin time but be anticoagulated to quite different
degrees. This study also used relatively high intensity anticoagulation. In this cohort, warfarin showed no overall benefit
because of the incidence of intracranial haemorrhage [2].
Dr Morgan’s review raises the argument that the incidence of stroke in different studies is variable. Also the
importance of increasing age differs in different studies. To
the factors of AF and age have to be added other clinical
variables such as hypertension, previous stroke, diabetes
and poor left ventricular function when evaluating the risk
of stroke. Dr Morgan points out that many other social and
cognitive risk factors could be added to these known clinical
factors which are particularly important in the elderly.
Three published studies have attempted to derive a profile of patients who are at higher than average risk of bleeding while taking oral anticoagulants. Van der Meer and
colleagues [3] demonstrated an increased risk of bleeding
for every 10 year increase in age of 46 to 57%.
In 1998 Beyth and colleagues developed an Outpatient
Bleeding Risk Index (OBRI) on a large cohort of patients
and subsequently evaluated it on a separate cohort [4]. The
OBRI evaluates age, history of stroke, diabetes, MI, GI
bleeding, severe anaemia and significant renal impairment.
Patients can then be divided into low risk, intermediate risk
and high risk. In the evaluated cohort the risk of bleeding in
12 months was 3, 12 and 48% for these three groups.
Kuijer et al. [5] undertook a similar exercise. The variables which they found to be predictive of bleeding were age
over 65, sex, with women more likely to bleed, and the presence of malignancy. In the validation group there was 4%
bleeding in the low risk group, 8% in the intermediate risk
group and 17% in the high risk group.
Both Kuijer and Beyth have developed a system that
seems to predict patients most likely to bleed. What is further needed is a refinement of this system, particularly for
the elderly, which looks at the many social and cognitive factors which Dr Morgan described in her review. Furthermore,
the elderly do not escape the influence of genetics. Patients
with variant alleles for CYP2C9 in the cytochrome system can
present with unanticipated over-anticoagulation [6].
Dr Morgan asks the question whether doctors are
under-treating AF in the elderly. There is already published evidence that this is so. In a community-based
study in the north-east of England a prevalence of AF in
the elderly of 4.7% was demonstrated. Using criteria from
recent AF studies the authors estimated that anywhere
from one-third to two-thirds of these AF patients would
have benefited from anticoagulation, depending upon the
criteria used to measure risk, yet only a quarter of patients
were receiving oral anticoagulants [7]. A survey conducted
in Australia demonstrated that while general practitioners
were better than cardiologists at identifying the risk of
stroke in AF patients, they were less likely to recommend
anticoagulation and were likely to overestimate the risk of
bleeding [8].
A word of caution should be sounded however. A recent
report of statistical modelling, incorporating data from USA
life tables up to age 100, demonstrated that the benefits of anticoagulation of ‘the oldest old’ were extremely small or nonexistent [9]. Even for individuals in their model with additional
risk factors for stroke as well as AF, anticoagulation appeared
to be of little benefit for those over 80 years of age. This work
needs to be confirmed in living patients but it serves to highlight the dilemma for clinicians treating the elderly.
Dr Morgan has asked important questions concerning
anticoagulation of elderly AF patients. There needs to be a
better method of predicting risk from anticoagulants in the
elderly which includes risk factors such as recurrent falls or
episodes of confusion particularly pertinent to the elderly.
There is also a need for more randomised clinical studies
which include the most difficult population: the over 75
years age group. Finally, there needs to be improved and
continuing education of doctors so that those patients who
would benefit from anticoagulation are offered safe, wellmonitored therapy.
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