michael s
(Michael S)
#1
23 Under what circumstances should the patient
with unstable angina undergo PTCA or CABG?
Diana Holdright
Until recently, published trials and registry data comparing early
invasive and conservative strategies in patients with unstable
angina (UA) and non-Q wave myocardial infarction (NQMI)
suggested no overall benefit from an early invasive approach.
Indeed, there was the impression that patients fared better with
an initial conservative approach. However, the most recently
published trial (FRISC II),^1 reflecting modern interventional
practice, new stent technology and adjunctive medical therapies
(e.g. the glycoprotein IIb/IIIa antagonists) together with
improved bypass and myocardial preservation techniques and
greater use of arterial conduits has shown significant mortality
and morbidity benefit from an early invasive approach.
The first trial to assess these two management strategies, TIMI
IIIB, randomised patients with UA/NQMI to angiography within
24–48 hours followed by PTCA/CABG if appropriate.^2 The
primary end point of death/MI/positive treadmill test at 6 weeks
was 18.1% for the conservative strategy and 16.2% for the
invasive strategy (p = NS). Death/MI occurred in 7.8% and 7.2%
at 6 weeks (p = NS) and in 12.2% and 10.8% at 1 year (p = NS).
However, 64% of patients crossed over to the invasive strategy
because of recurrent angina or an abnormal treadmill test, raising
doubts about the clinical application of the trial results.
The VANQWISH study similarly randomised patients with
NQMI.^3 Death or non-fatal MI occurred in 7% (invasive) vs 3.2%
(conservative, p = 0.004) at hospital discharge, in 10.3% vs 5.7%
at 1 month (p = 0.0012) and in 24% vs 18.6% at 1 year (p = 0.05).
However, with longer follow up (23 months) the mortality
difference was lost. Of note, 9% of eligible patients were excluded
due to very high-risk ischaemic complications. In contrast to TIMI
IIIB, only 29% patients crossed over from the conservative arm.
The OASIS registry highlighted different management
strategies for UA by country.^4 Angiography rates varied from 2%
(Poland) to 58% (US) and 60% (Brazil) at 7 days. Rates of PTCA
and CABG by 7 days were highest in the US and Brazil (15.9%
and 11.7%) and lowest in Canada/Australia/Hungary/Poland
(5% and 1.6%). However, MI and death rates were similar for all
