Major Finding: ST-elevation myocardial infarction patients who underwent multivessel percutaneous coronary intervention had an 11% rate of shock, 9% rate of renal failure, and 7.5% rate of in-hospital mortality. In patients with single vessel PCI, the rates were 8%, 7%, and 6.2%, respectively.
Data Source: Retrospective analysis of 24,106 Medicare beneficiaries who underwent primary PCI for STEMI during fiscal year 2007.
Disclosures: Dr. Kugelmass had no financial disclosures relevant to this study.
ATLANTA — One in seven U.S. patients undergoing percutaneous coronary intervention for an ST-elevation myocardial infarction received multivessel revascularization, despite society guidelines that recommend revascularizing only the culprit coronary artery, according to a retrospective review of more than 24,000 Medicare beneficiaries.
“Based on this retrospective analysis, continuing to follow the American College of Cardiology/American Heart Association recommendations that ST-elevation myocardial infarction patients undergo percutaneous coronary intervention of only the culprit vessel at the time of initial reperfusion therapy is prudent,” Dr. Aaron D. Kugelmass said at the annual meeting of the American College of Cardiology. But, he added, “We feel that a prospective assessment of this question is needed to identify the best PCI strategy for STEMI patients with multivessel coronary artery disease.”
The retrospective nature of his study, and hence its inability to gather information on what prompted operators to perform multivessel PCI, created a major limitation, said Dr. Kugelmass, chief of the division of cardiology at Baystate Medical Center in Springfield, Mass.
“There is potential for a lot of confounding [in the current study], and I think the biggest confounder is that we don't know what we're dealing with,” that is, what were the clinical characteristics of patients that led operators to perform PCI on more than one coronary vessel? “The advantage of a prospective registry is that you can ask questions about operator intent. Randomizing patients to single-vessel versus multivessel PCI at the time of primary PCI for STEMI may be ambitious. But a prospective registry may not be bad for identifying exactly which patients” get multivessel PCI, he said.
“Most operators have a pretty good idea of what they're doing. In real-world practice, they can often discriminate which patients are likely to benefit and which ones won't. Operators usually get it right. But to extrapolate from this to changing the ACC/AHA guidelines, when we see no advantage and without prospective information, would be a bold move.”
Dr. Kugelmass speculated that several different circumstances probably prompt an operator to perform multivessel primary PCI in patients with a STEMI: One scenario involves patients with multiple sites of plaque rupture, defined by angiography, in whom the culprit lesion was not immediately identified and who were quite sick and did not improve following initial revascularization, prompting the operator to treat a second vessel. Another situation involves patients in whom the first candidate vessel contains a total chronic occlusion, which leads to treatment of a second coronary artery. A third case includes patients who had rapid reperfusion of a “straightforward” lesion, but despite that the operator decided to treat another vessel at the same time.
“Some operators believe that complete revascularization should be done, and that it should be done” during the primary PCI, Dr. Kugelmass said.
His study used data collected in the Medicare Provider Analysis and Review file, an administrative database for Medicare patients, during fiscal year 2007, covering patients treated during October 2006–September 2007. The database included 24,106 evaluable beneficiaries who underwent primary PCI for a STEMI, with 20,828 patients (86%) who underwent single-vessel PCI and 3,278 (14%) who received multivessel PCI.
Patients who underwent multivessel PCI had a significantly higher rate of shock associated with their STEMI, 11% compared with 8%, and a significantly higher prevalence of acute renal failure, 9% compared with 7%.
The multivessel PCI patients also had a significantly higher mortality rate while hospitalized following PCI, 7.5% compared with 6.2%. In a risk-adjusted analysis that took into account 31 potential demographic and clinical confounders, the multivessel-PCI patients had a higher than expected mortality rate, and the single-vessel PCI patients had a slightly lower than expected mortality rate.
Despite this, in a multivariate model, multivessel PCI was not a significant determinant of in-hospital mortality, nor did it confer a survival advantage. The strongest mortality predictor in the analysis was cardiogenic shock. Other significant determinants included older age, end-stage renal disease, prior coronary bypass surgery, and a ventricular arrhythmia.
“At first pass, the multivessel PCI patients appear to be sicker, but there is potential for a lot of confounding,” Dr. Kugelmass said.