michael s
(Michael S)
#1
32 What is the mortality rate for cardiogenic
shock complicating myocardial infarction? How
should such patients be managed to improve
outcome and what are the results?
Prithwish Banerjee and Michael S Norrell
The advent of the thrombolytic era has not altered the incidence
or mortality rate for cardiogenic shock complicating myocardial
infarction (MI). It still represents almost 10% of patients with MI,
with almost 90% dying within 30 days.^1
Pooled results from retrospective, unrandomised data or
historical reviews, which examined the effects of early re-
vascularisation, have suggested reduced mortality following bypass
surgery (CABG) or coronary angioplasty (PTCA) to 33%^2 and 42%^3
respectively. Recently, a few randomised trials have attempted to
compare such early (within 48 hours) revascularisation with a
strategy of initial medical stabilisation. The latter might include
thrombolysis, inotropic support and intra-aortic balloon pump
counterpulsation (IABP), still with the option of delayed inter-
vention. It is unfortunate that most of these studies have faltered on
slow patient recruitment^4 leaving only one completed study
(SHOCK, SHould we emergently revascularise Occluded
Coronaries for Shock) to guide our management of these patients.^5
Over a 5 year period, the SHOCK trial randomised 302 patients
to receive either early revascularisation within hours from
randomisation, or initial medical stabilisation with the option of
delayed intervention. Thirty day mortality was reduced in the
early intervention group (46% vs 56%) with this benefit
extending out to 6 months and particularly apparent in the
younger (<75 years) age group. The low mortality in the control
group is striking, and explains the lack of a large difference
between the two groups. Nevertheless, it suggests benefit even
with a relatively aggressive conservative policy in these patients.
Because of trial recruitment difficulties it is unlikely that
further randomised data will emerge in the foreseeable future.
Evidence from the SHOCK trial would seem to suggest that at
present it would be reasonable to consider an aggressive
approach with early revascularisation in patients with shock
complicating myocardial infarction. However, access to surgery
should be available – 36% of patients required this intervention
