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Revascularisation choices

Systematic review
Results
Comment

Most of us would agree that cardiac ischaemia is not a good thing, and most of us would want someone to do something about it if it was our heart that was affected. In such circumstances most of us would follow the advice of our physician or surgeon about what was the most appropriate way to proceed for us as individuals. We might, though, want to consider what is best on average, and a meta-analysis comparing two approaches provides some information [1].

Systematic review

The review sought studies reporting on minimally invasive direct coronary bypass with left internal thoracic artery anastomosis compared with percutaneous transluminal coronary artery stenting. They had to compare the two interventions for isolated lesions of the left anterior descending artery as a primary intervention. A number of different outcomes were sought, either within 30 days of the procedure, or at maximum follow up.

Results

Information was available on eight patient groups in 12 studies, including six prospective randomised studies with 802 patients.

Results for the main outcomes in these six randomised trials are in Table 1. For repeat revascularisation and recurrence of angina there was a greater rate of events with stenting than with surgery, with numbers needed to harm (NNH) of 10 and 6 respectively. Major adverse coronary or cardiovascular events also appeared to be increased with stenting, though this outcome was reported in only two of the trials. There were no differences for myocardial infarction either early or late, or stroke or TIA, or mortality (Table 1).



Table 1: Main outcomes of trials comparing coronary artery stents with minimally invasive thoracic artery bypass surgery



Number events/total
(%)
Event
Number of trials
Coronary artery stent
Minimally invasive thoracic artery bypass
Relative risk
(95% CI)
NNH
(95% CI)
Repeat vascularisation at maximum follow up
6
57/425
(13)
14/377
(3.7)
3.8 (2.2 to 6.6)
10 (7.4 to 17)
Recurrence of angina
4
77/259
(30)
36/259
(14)
2.1 (1.5 to 3.0)
6.3 (2.4 to 11)
Major adverse coronary or cerebrovascular event
2
48/159
(30)
21/159
(13)
2.3 (1.4 to 3.6)
5.9 (3.9 to 12)
MI within 30 days postoperatively
5
14/378
(3.7)
9/329
(2.7)
1.3 (0.6 to 3.0)
Not calculated
MI at maximum follow up
5
8/327
(2.4)
13/375
(3.5)
0.7 (0.3 to 1.6)
Not calculated
Post procedure stroke of TIA
3
4/209
(1.9)
1/209
(0.5)
2.5 (0.5 to 13)
Not calculated
Mortality at maximum follow up
4
3/179
(1.7)
6/175
(3.4)
0.6 (0.2 to 1.9)
Not calculated


Figure 1 shows that trials were consistent in having low revascularisation rates with surgery, but had very different revascularisation rates with stents. The two largest trials, in particular, were very different in their outcomes, one showing a large difference, the other none. Repeating the analyses omitting the trial with the largest difference resulted in a higher NNH of 16 that was still statistically significant, while omitting the trial with no difference resulted in a more important NNH of 7.5.



Figure 1: Revascularisation procedures with stents and surgery





Comment

Given the choice between a relatively simple procedure that would probably allow one to go home and watch the football that afternoon or someone fiddling around inside one's chest, Bandolier would tend to vote for the football. But is that the right choice? This meta-analysis would suggest that it was not.

An accompanying editorial [2] argues that it may well not be the right choice for many, especially those with more severe disease, or more risk factors, like diabetics. It points out that the trials were limited in follow up, so limiting any observation of mortality benefit (and there were only nine deaths observed in 350 or so patients), and that trials usually recruited patients with less severe conditions.

When stents come with a 1 in 10 chance of having a second procedure, and a 1 in 3 chance of recurrence of angina, the football choice does seem less attractive.

References:

  1. O Aziz et al. Meta-analysis of minimally invasive internal thoracic artery bypass versus percutaneous revascularisation for isolated lesions of the left anterior descending artery. BMJ 2007 334: 617-621. 2 DP Taggart. Coronary revascularisation. BMJ 2007 334: 593-594.

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