Review question
In people with narrowing of multiple coronary arteries (blood vessels that surround and supply the heart with blood), along with one completely occluded (blocked) that is causing a heart attack, whether it is better to open all arteries or only the one that is causing the heart attack.
Background
The co-existence of multiple significantly narrowed coronary vessels (called multi-vessel disease) with a completely occluded coronary artery that is causing the heart attack, is commonly seen among people having a heart attack. Current treatment of these narrowed or completely obstructed coronary arteries involves an intravascular (within a blood vessel) procedure known as percutaneous coronary intervention, which uses a balloon that is positioned and inflated at the site of the blockage thereby opening the artery and restoring normal blood flow. This is usually followed by placement of a stent (small mesh tube) to avoid the previously narrowed arteries closing again. In addition to the blocked artery, there may be other narrowed coronary arteries, but several cardiology societies recommend intervening only on the vessel(s) causing the heart attack thereby leaving the other narrowed arteries untreated unless the person continues to have symptoms.
Study characteristics
We searched for clinical trials in adults who had percutaneous coronary intervention for the management of heart attack and multi-vessel disease. The evidence is current to 4 January 2017. Only four trials reported funding from government organisations or charitable institutions. The other trials did not mention the source of funding and no private companies were mentioned as sources of finance. In the included trials, both the participants and researchers were aware of what treatment the participants received which may have biased the results. One trial ended enrolment earlier than planned because the difference between treatment was significant. This may have overestimated the difference between intervention groups. For most trials, the number of participants that were included was not enough to see a potential difference between treatments.
Key results
We included nine clinical trials with 2633 people with heart attack and multi-vessel disease. Compared with participants who underwent opening of only the coronary artery that caused heart attack, people who underwent treatment on all narrowed vessels had fewer deaths from diseases of the heart and blood supply (called cardiovascular disease), required fewer treatments to open the problematic coronary arteries, and had fewer heart attacks at the end of one year or later since the treatment. Based on our analyses, although the treatment on all narrowed vessels appears to be a better treatment strategy, there still exists a need for more well-designed clinical trials to confirm that this approach is associated with fewer deaths from cardiovascular diseases or heart attack, or both.
Quality of the evidence
The evidence is of very low quality. For instance, the number of participants in the included studies was insufficient, the medical team was aware of the study group that the participants were allocated to and that may have affected our conclusions. There is a need for well-designed clinical trials with more participants to determine which treatment strategy is superior.
Compared with culprit-only intervention, the complete revascularisation strategy may be superior due to lower proportions of long-term cardiovascular mortality, long-term revascularisation, and long-term non-fatal myocardial infarction, but these findings are based on evidence of very low quality. TSA also supports the need for more RCTs in order to draw stronger conclusions regarding the effects of complete revascularisation on long-term all-cause mortality, long-term cardiovascular mortality, and long-term non-fatal myocardial infarction.
Multi-vessel coronary disease in people with ST elevation myocardial infarction (STEMI) is common and is associated with worse prognosis after STEMI. Based on limited evidence, international guidelines recommend intervention on only the culprit vessel during STEMI. This, in turn, leaves other significantly stenosed coronary arteries for medical therapy or revascularisation based on inducible ischaemia on provocative testing. Newer data suggest that intervention on both the culprit and non-culprit stenotic coronary arteries (complete intervention) may yield better results compared with culprit-only intervention.
To assess the effects of early complete revascularisation compared with culprit vessel only intervention strategy in people with STEMI and multi-vessel coronary disease.
We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, World Health Organization International Clinical Trials Registry Platform Search Portal, and ClinicalTrials.gov. The date of the last search was 4 January 2017. We applied no language restrictions. We handsearched conference proceedings to December 2016, and contacted authors and companies related to the field.
We included only randomised controlled trials (RCTs), wherein complete revascularisation strategy was compared with a culprit-only percutaneous coronary intervention (PCI) for the treatment of people with STEMI and multi-vessel coronary disease.
We assessed the methodological quality of each trial using the Cochrane 'Risk of bias' tool. We resolved the disagreements by discussion among review authors. We followed standard methodological approaches recommended by Cochrane. The primary outcomes were long-term (one year or greater after the index intervention) all-cause mortality, long-term cardiovascular mortality, long-term non-fatal myocardial infarction, and adverse events. The secondary outcomes were short-term (within the first 30 days after the index intervention) all-cause mortality, short-term cardiovascular mortality, short-term non-fatal myocardial infarction, revascularisation, health-related quality of life, and cost. We analysed data using fixed-effect models, and expressed results as risk ratios (RR) with 95% confidence intervals (CI). We used GRADE criteria to assess the quality of evidence and we conducted Trial Sequential Analysis (TSA) to control risks of random errors.
We included nine RCTs, that involved 2633 people with STEMI and multi-vessel coronary disease randomly assigned to either a complete (n = 1381) versus culprit-only (n = 1252) revascularisation strategy. The complete and the culprit-only revascularisation strategies did not differ for long-term all-cause mortality (65/1274 (5.1%) in complete group versus 72/1143 (6.3%) in culprit-only group; RR 0.80, 95% CI 0.58 to 1.11; participants = 2417; studies = 8; I2 = 0%; very low quality evidence). Compared with culprit-only intervention, the complete revascularisation strategy was associated with a lower proportion of long-term cardiovascular mortality (28/1143 (2.4%) in complete group versus 51/1086 (4.7%) in culprit-only group; RR 0.50, 95% CI 0.32 to 0.79; participants = 2229; studies = 6; I2 = 0%; very low quality evidence) and long-term non-fatal myocardial infarction (47/1095 (4.3%) in complete group versus 70/1004 (7.0%) in culprit-only group; RR 0.62, 95% CI 0.44 to 0.89; participants = 2099; studies = 6; I2 = 0%; very low quality evidence). The complete and the culprit-only revascularisation strategies did not differ in combined adverse events (51/2096 (2.4%) in complete group versus 57/1990 (2.9%) in culprit-only group; RR 0.84, 95% CI 0.58 to 1.21; participants = 4086; I2 = 0%; very low quality evidence). Complete revascularisation was associated with lower proportion of long-term revascularisation (145/1374 (10.6%) in complete group versus 258/1242 (20.8%) in culprit-only group; RR 0.47, 95% CI 0.39 to 0.57; participants = 2616; studies = 9; I2 = 31%; very low quality evidence). TSA of long-term all-cause mortality, long-term cardiovascular mortality, and long-term non-fatal myocardial infarction showed that more RCTs are needed to reach more conclusive results on these outcomes. Regarding long-term repeat revascularisation more RCTs may not change our present result. The quality of the evidence was judged to be very low for all primary and the majority of the secondary outcomes mainly due to risk of bias, imprecision, and indirectness.