Stress Test Risk Classification And Health Status Outcomes After Chronic Total Occlusion Angioplasty

Chronic total occlusions (CTO) are present in over 20% of patients with obstructive coronary artery disease the time of diagnostic angiography.  These lesions can be difficult to treat, but recent advances in crossing these lesions have increased success rates of angioplasty to over 90%.

Current American College of Cardiology/American Heart Association Appropriate Use Criteria (AUC) for management of stable ischemic heart disease use two key criteria to identify appropriate candidates for revascularization – patients’ symptom burden after treatment with medical therapy, and risk for adverse events, largely determined by the results of non-invasive stress tests.  Clinicians routinely incorporate non-invasive stress testing in the decision-making process when selecting a strategy of medical therapy alone or medical therapy plus revascularization when treating symptomatic patients with CTOs, and sometimes withhold invasive therapy from patients with low-risk stress test findings.

Since relief of symptoms is frequently the primary indication for CTO PCI,⁴ this study from the Outcomes, Patient Health Status, and Efficiency IN Chronic Total Occlusion Hybrid Procedures (OPEN-CTO) registry was designed to better understand the association between stress test risk classification, extent of coronary ischemia and patients’ health status (their symptoms, functional capacity and quality of life).

How was this study conducted?

The OPEN CTO registry is a prospective, single-arm study that prospectively enrolled consecutive patients with CTOs who underwent attempted CTO PCI at 12 US sites between January 21, 2014, and July 22, 2015. In total, 1000 patients were enrolled, and their symptoms, function, and quality of life were assessed with the coronary artery disease-specific Seattle Angina Questionnaire (SAQ) in followup. Long-term health status change after CTO PCI was the primary focus of the study, defined as the change in the Angina Frequency, Quality of Life and Summary Score domains of the SAQ between baseline and 12-month follow-up interviews.

Data were collected for the most recent stress test prior to the angioplasty procedure, including treadmill exercise stress testing, exercise or pharmacologic echocardiography, exercise or pharmacologic single photon emission computed tomography, pharmacologic positron emission tomography or pharmacologic cardiac magnetic resonance imaging.

Stress test results were reviewed by the treating physician, and categorized into low, intermediate or high-risk classes by operators based upon their working knowledge of the 2012 Appropriate Use Criteria for percutaneous intervention in patients with stable ischemic heart disease.  Given that the recently updated ACC/AHA Appropriate Use Criteria document defines appropriateness by categorizing stress test findings into either low risk (LR) or intermediate to high risk (IHR) findings, we compared the health status outcomes of patients who had LR to those with IHR findings

What were the findings and how are they significant?

Nearly 1 in 10 patients undergoing successful CTO PCI in the OPEN CTO registry had low risk findings on stress testing performed prior to the procedure.  We observed large, clinically important improvements in health status from baseline to 1-year after CTO PCI as quantified by each SAQ domain in both patients with LR and IHR stress tests.  Health status improvement on SAQ QoL and Summary domains was similar between groups, with greater reduction in angina symptoms among patients with IHR stress test findings.  Moreover, we found no correlation between the proportion of ischemic myocardium on stress testing and symptom improvement after CTO PCI.

In total, while we found that patients with IHR stress tests experience a greater reduction in angina symptoms after CTO PCI, patients with refractory symptoms and lower risk stress test findings were also likely to experience robust improvement in angina symptoms, with similar improvement in quality of life and overall health status, suggesting that these procedures should not be withheld from symptomatic patients with appropriate indications for revascularization simply because of low-risk findings on stress tests.  CTOs remain common, and providers should consider referral to experienced CTO angioplasty centers if patients continue to experience lifestyle-limiting symptoms on optimal medical therapy.

These findings are described in the article entitled Association of Stress Test Risk Classification With Health Status After Chronic Total Occlusion Angioplasty (from the Outcomes, Patient Health Status and Efficiency in Chronic Total Occlusion Hybrid Procedures [OPEN-CTO] Study), recently published in the journal The American Journal of Cardiology.

This work was conducted by Adam C. Salisbury, John T. Saxon, Kensey L. Gosch, Mohammed Qintar, John A. Spertus, David J. Cohen, and Aaron Grantham from Saint Luke’s Mid America Heart Institute, James Sapontis from Monash Heart Hospital, William L. Lombardi from the University of Washington School of Medicine, and Dimitri Karmpaliotis, Jeffery W. Moses, and Ajay J. Kirtane from Columbia Univeristy, New York Presbyterian Hospital.