Real-World Analysis Supports Culprit-Lesion Over Multivessel PCI in STEMI Patients

November 06, 2014

LONDON, UK — A real-world analysis of ST-segment-elevation MI (STEMI) patients undergoing primary PCI has shown that treating the culprit lesion only is associated with a lower rate of in-hospital major adverse cardiovascular events (MACE) and lower mortality at 30 days and 1 year compared with individuals who undergo a more comprehensive multivessel intervention[1].

For those undergoing culprit-lesion primary PCI, the in-hospital MACE, 30-day mortality, and 1-year mortality rates were 4.6%, 4.7%, and 7.4%, respectively, whereas the corresponding event rates were 7.2%, 7.7%, and 10.1% for patients undergoing multivessel PCI. These differences were statistically significant and support the current European practice guidelines that recommend culprit-lesion PCI in STEMI patients, according to the researchers.

The results, which are published November 4, 2014 in Circulation: Cardiovascular Quality and Outcomes, contrast with the recent findings from the Complete Versus Lesion-Only Primary PCI Trial (CVLPRIT). As reported by heartwire when the results were presented at the European Society of Cardiology 2014 Congress, CVLPRIT compared an infarct-related artery revascularization strategy against complete revascularization at the time of index admission and showed the more comprehensive approach significantly reduced the risk of MACE at 1 year.

Similarly, the Preventive Angioplasty in Acute Myocardial Infarction (PRAMI) study also showed treating nonculprit lesions in STEMI patients resulted in a significant 65% relative reduction in the MACE risk, a reduction driven by decreases in nonfatal MI and refractory angina.

Speaking with heartwire , Dr Bilal Iqbal (Royal Brompton and Harefield NHS Foundation Trust, Middlesex, UK), the lead investigator of the newest analysis, said both PRAMI and CVLPRIT were excellent studies but pointed out that the end points in those trials were composite end points. In CVLPRIT, the primary MACE end point included all-cause mortality, recurrent MI, heart failure, and repeat revascularizations. In PRAMI, the primary end point included death from cardiac causes, nonfatal MI, and refractory angina.

"The end points that they use in their study are very different from the end point we have used," said Iqbal. "We looked at mortality, which is a hard end point. If you look at PRAMI and CVLPRIT, they have composite end points, which include death, MI, and more important, include end points like refractory angina and ischemia-driven revascularization. These events can be dictated by the treatment strategy. For example, if you're not going to be treating bystander coronary disease then you are going to be getting refractory angina. You are going to have ischemia-driven revascularization."

In PRAMI and CVLPRIT, when all-cause mortality was assessed as an individual end point, there was no difference between culprit-lesion and multivessel coronary revascularization. Iqbal also noted that the CVLPRIT study compared complete revascularization prior to hospital discharge, whereas their analysis compared only culprit- vs multivessel interventions at the time of the index intervention.

"There are differences between all these studies, and it does make it very difficult to compare and generalize," said Iqbal.

The London Analysis

For their analysis, Iqbal and his collaborators, all of whom are part of the London Heart Attack Center Group, included 3984 STEMI patients with multivessel disease undergoing primary PCI at eight tertiary cardiac centers in London, UK. Of these, 3429 patients underwent culprit-lesion revascularization and 555 patients were treated with complete revascularization.

In their analysis, culprit-lesion PCI was associated with lower mortality at 30 days and 1 year. For in-hospital outcomes, treating the culprit lesion resulted only in lower in-hospital MACE, a reduction that was driven by significant reductions in reinfarction, reintervention, and mortality. In a multivariate-adjusted model, culprit-lesion PCI was an independent predictor of death at 30 days (hazard ratio 0.45; P<0.001) and 1 year (hazard ratio 0.65; P=0.011). For the in-hospital outcomes, culprit-lesion PCI was an independent predictor of MACE, as well as in-hospital reinfarction and in-hospital mortality.

In a propensity-matched analysis adjusted for differences in demographics and clinical, anatomic, and procedural variables, the results were consistent with the overall findings.

To heartwire , Iqbal said their study is a registry study, but the results are in line with other registry analyses showing that culprit-vessel revascularization at the time of the index intervention is associated with better outcomes. He pointed out that despite adjustments to their risk models, registry studies are subject to potential confounding, which is one of the drawbacks. He suggests their results should be viewed as hypothesis generating.

"CVLPRIT and PRAMI have certainly provided a lot of evidence in the treatment of multivessel disease in the context of STEMI, but there are more trials under way, particularly the COMPLETE trial," said Iqbal. "PRAMI and CVLPRIT, those are randomized trials — those are hard data — but we still need to wait for other trials to come in so we can refine our treatment strategy for these patients."

Officially known as the Complete vs Culprit-Only Revascularization to Treat Multi-vessel Disease After Primary PCI for STEMI, the COMPLETE study is being led by researchers at the Population Health Research Institute out of McMaster University in Ontario. The investigators plan to enroll approximately 4000 patients, and full results are expected in 2018.

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