Should bad angina be treated with stents or tablets first?
10 years ago it was not at all clear if it was best to operate on all patients who presented with severe angina or to try initially to simply manage these patients with tablets. The operation would be either placing a stent into a narrowed artery or performing coronary artery bypass surgery (CABG).
To answer this question as to which strategy was better – ‘early invasive’ or ‘wait and see’ a team of British Cardiologists performed a clinical trial called RITA3 (The Third Randomized Intervention Treatment of Angina) They put 1810 patients presenting with unstable angina into 2 groups (immediate intervention or wait and see) and monitored them for 5 years.
54% (485/895) of the rapid intervention group underwent revascularization – roughly 2 stents for every one CABG . 10.3% (94/915) of the wait and see patients had an intervention in the next 5 years. The trial ran for 5 years and the results showed that not only do you have less angina but are less likely to have a heart attack or dying by intervening rapidly. This came at the cost of performing many more invasive procedures.
The results also showed there was much more benefit when you had rapid intervention if you had a higher risk of dying from the outset. If you were at low risk the benefit was minimal. The message was clear: operate within 72 hours of symptom onset to get the maximum benefit.
Now the 10year follow up results are available from the trial and the data at first sight does not seem to be so clear cut. The authors Rob Henderson from Nottingham and colleagues have looked at government death records and shown that the beneficial effects of an early invasive treatment for unstable angina have disappeared by 10 years.
The graph below shows the cumulative death rate divided into 3 risk groups low, medium and high. As time goes on the chances of dying go up and if the data is collected for long enough all patients will die and there will therefore be 100% cumulative mortality (deaths) which will be seen on the left (y axis).
The initial interpretation amongst some of the cardiology press/fraternity seems to be that there is no point in performing early revascularization. After all there were many more patients undergoing unpleasant procedures in the early invasive group.
However lets look more carefully at the data …or lack of it. There is no data from the 10 year follow up about how many heart attacks people have had or whether they have more or less angina. It only tells us about the number of people who had died. This is important as most people who have an operation do so to improve the symptoms they are getting. It’s a bonus if they make you live longer.
Furthermore when you look closely at the curves there appears to be a clear divergence of the lines in the middle years especially in those at higher risk. This will mean for a significant period of time there will be more people alive if they have had an early interventional strategy. After all if you leave a trial long enough you will eventually see all curves converge at 100% mortality.
So if I were admitted to hospital with unstable angina I would still like an early angiogram with a follow-on interventional procedure if I had a major narrowing in my coronary arteries. I would also like to be given the best combination of medical therapy which would include a high dose of statins (see separate articles) and antiplatelet drugs.
1.Henderson R et al J Am Coll Cardiol. 2015;66(5):511-520