Study Suggests Nonculprit Revascularization Enhances Health Status of STEMI Patients

Opening nonculprit arteries either at the time of or shortly after primary PCI is associated with clinically meaningful improvements in angina and quality of life (QoL) over the next year in patients with STEMI, an observational study suggests. The use of multivessel revascularization is not, however, related to clinical outcomes.

These findings fill a gap created by prior randomized trials of complete vs culprit-only revascularization that have failed to look at the impact on health status, study author John Spertus, MD, MPH, of Saint Luke’s Mid America Heart Institute (Kansas City, MO), told TCTMD.

“What this should highlight is that if you’re going to test these 2 strategies, you ought to also measure the patients’ symptoms, function, and quality of life,” Spertus said. “And I think if [researchers] do that, they’ll give us a more complete insight into the risks and benefits of doing complete vs incomplete revascularization.”

For the study, published in the November 10, 2015, issue of the Journal of the American College of Cardiology, the investigators looked at data from TRIUMPH, a prospective cohort study that enrolled 4,340 patients with acute MI at 24 US sites between April 2005 and December 2008.

The current analysis included 664 patients with STEMI who had multivessel disease and did not have a history of CABG. Among them, 38% underwent multivessel revascularization, defined as treatment of all major coronary stenoses during the index hospitalization or within 6 weeks of discharge with either CABG or PCI (PCI was used in 88%). Most of the nonculprit interventions (64.1%) were staged during the initial admission, with 8.0% performed shortly after discharge and 27.9% performed during primary PCI.

Angina frequency and QoL improved through 1 year regardless of the use of multivessel revascularization, but the gains were greater in patients who had their nonculprit arteries opened after patient differences were accounted for using multivariate regression with inverse probability weighting. Using the Seattle Angina Questionnaire (SAQ), angina frequency score was a mean 4.45 points higher (95% CI 0.99-7.91) and QoL score a mean 6.63 points higher (95% CI 2.67-10.59) in the patients who underwent multivessel vs culprit-only revascularization. Both differences are clinically meaningful and at least as large as those seen in the COURAGE trial, Spertus told TCTMD.

Timing of complete revascularization (ie, during primary PCI, later in the hospital stay, or after discharge) did not influence the findings.

At 1 year, there were no differences between the multivessel and culprit-only revascularization groups in mortality, repeat revascularization, recurrent MI, or severe angina, although the study was not powered to detect disparities in mortality or repeat revascularization, Spertus and colleagues note.

Patient-Reported Outcomes Needed in Trials

When and how to treat nonculprit vessels in STEMI patients remains debated, although accumulating evidence supports intervening on them either at the time of primary PCI or later in a staged fashion, which has been reflected in a recent focused guideline update.

However, those recent trials, though showing a benefit of multivessel PCI on hard clinical outcomes, did not focus on patient-reported outcomes and offered no data related to long-term impacts on health status.

The current analysis complements the trial findings but is subject to various limitations, including the observational design, the potential influence of unmeasured confounding or selection bias because of the lack of information on why one strategy was chosen over the other, and the fact that SAQ data were missing in about one-third of patients at 1 year.

“Our findings thus emphasize the need for future randomized trials to compare these 2 revascularization strategies and to explicitly measure the effects of treatment strategy on QoL, an outcome of critical importance to patients,” Spertus and colleagues write.

Assessing QoL in STEMI a Challenge

In an accompanying editorial, Timothy Henry, MD, of Cedars-Sinai Heart Institute (Los Angeles, CA), and Anthony Gershlick, MBBS, of the University of Leicester (Leicester, England), say that “determining the effect of any therapy or treatment strategy on QoL depends clearly on the quality of the source data, and herein lie 2 problems for this group [of researchers]—the overall lack of certainty that multivessel PCI is beneficial, and some inherent weaknesses in data available to these investigators.”

First, it is uncertain whether multivessel PCI is beneficial because of the lack of differences observed in clinical outcomes, they say. And second, there are some holes in the data, including missing SAQ data, ambiguity about the definition of baseline (whether it is 1 week before STEMI, at the time of STEMI, or the day after PCI), and the use of registry data that are several years old and do not reflect changes in practice patterns and outcomes that have occurred since then.

Although these shortcomings underscore the importance of studying QoL prospectively in clinical trials, Henry and Gershlick note that it can be challenging in the acute setting of STEMI because of all of the factors that go into decision making.

“What this group has done well is to highlight (again) that there is more to clinical research studies than hard endpoints, with QoL often felt to be ‘soft and unimportant’—something our patients (and families) would contest vigorously,” the editorialists write.

What Should Be ‘Standard of Care’?

Shamir Mehta, MD, MSc, of McMaster University (Hamilton, Canada), told TCTMD that this is an important study and also said the authors should be congratulated, adding that “I agree with the message and the plea to include QoL as an outcome in trials.” Mehta is the principal investigator for the ongoing COMPLETE trial, which includes assessments of QoL.

He added, however, that “we have known for years that PCI is effective in reducing angina. But that is not really the question that needs to be answered. The question is whether a routine preventive PCI strategy where everyone receives a stent to the nonculprit lesion to prevent an MI or death should be the standard of care.” If the answer is yes, he said, it “would result in a fundamental change in practice globally and result in tens of thousands, if not hundreds of thousands, more PCI procedures per year globally.”

Spertus said a rational extension of the current study would be to develop tools to determine which patients are most likely to have reductions in angina and improvements in quality of life from complete revascularization and which ones will not.

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Sources: 
1. Jang J-S, Spertus JA, Arnold SV, et al. Impact of multivessel revascularization on health status outcomes of patients with ST-segment elevation myocardial infarction and multivessel coronary artery disease. J Am Coll Cardiol. 2015;66:2104-2113.
2. Henry TD, Gershlick A. Going beyond the hard endpoints: “quality of life” may be dependent on quality of available data [editorial]. J Am Coll Cardiol. 2015;66:2114-2115.

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