Impact of Incomplete Angiographic Revascularization After PCI in ACS

Amy Leigh Miller, M.D., Ph.D.; Joseph Loscalzo, M.D., Ph.D.


AccessMedicine from McGraw-Hill 

The relative benefit of complete versus incomplete revascularization remains a topic of debate. Using data from the Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) trial, Rosner and colleagues (2013) compared outcomes with complete and incomplete revascularization in patients presenting with acute coronary syndrome. ACUITY was a multicenter, randomized trial comparing three therapeutic strategies in moderate- to high-risk patients with non-ST-segment elevation acute coronary syndrome: heparin plus glycoprotein IIb/IIIa, bivalirudin plus glycoprotein IIb/IIIa, and bivalirudin monotherapy. All patients underwent angiography within 72 h of randomization and, at the discretion of their treating team, were managed with percutaneous coronary intervention (PCI), bypass surgery, or medical management. This analysis utilized the subset of patients managed with PCI for whom complete quantitative coronary angiography (QCA) was performed on both the baseline and post-PCI angiograms, allowing objective determination of complete or incomplete revascularization. Patients with a history of bypass surgery were excluded from the analysis.

Analyses were performed using QCA diameter stenosis cutoffs of ≥30%, ≥40%, ≥50%, ≥60%, and ≥70%, with corresponding prevalence rates of incomplete revascularization of 75%, 55%, 37%, 25%, and 17%. With a QCA threshold of ≥50% stenosis, untreated lesions in the treated vessel were observed in 19.2% of patients; untreated lesions in other vessels were observed in 24.2% of patients. Clinical predictors of incomplete revascularization (≥50% cutoff) included older age, greater weight, renal insufficiency, hypertension, elevated cardiac biomarkers at presentation, higher Thrombolysis in Myocardial Infarction (TIMI) risk score, and three-vessel disease. For all stenosis cutoffs, incomplete revascularization was significantly associated with higher rates of 1-year major adverse cardiovascular events (MACE). Greater MACE rates and higher hazard ratios for MACE were observed with increasing diameter stenosis cutoff. A diameter stenosis cutoff of 44% optimized the balance of sensitivity and specificity for MACE. MACE rates did not differ between patients with unrevascularized chronic total occlusions and incompletely revascularized patients without chronic total occlusions. In stepwise Cox multivariable regression, incomplete revascularization was independently associated with MACE (hazard ratio, 1.36; 95% confidence interval, 1.12–1.64).

While ACUITY was a randomized trial, neither the choice to revascularize nor the degree of revascularization was randomized in the trial; consequently, this is a retrospective observational analysis. Further work is needed to determine if complete revascularization can, in fact, improve patient outcomes. Importantly, the study underscores a weakness of the existing incomplete revascularization studies, which lack a uniform threshold for complete versus incomplete revascularization. Widely disparate rates of incomplete revascularization were observed as a function of diameter stenosis threshold. A standard definition of incomplete revascularization will facilitate future research to determine the clinical significance of the completeness of revascularization.