ORBITA-STAR Highlights Variability in Symptom Changes Post-PCI

Verifying patient symptoms with an ischemic stimulus on the cath lab table can help predict which stable patients with coronary artery disease will benefit from PCI, ORBITA-STAR, an n-of-1 study, shows.

Patients with single-vessel CAD undergoing PCI who had their symptoms confirmed with an ischemic balloon occlusion test were more likely to be free from angina during follow-up, while residual symptoms were more likely to continue if the pain or discomfort felt with the ischemic stimulus wasn’t the same as their day-to-day symptoms, report investigators.

“ORBITA-STAR provides data to inform precision medicine in the field of stable angina,” Christopher Rajkumar, MBBS (Imperial College London, England), and colleagues write in the July 2, 2024, issue of Journal of the American College of Cardiology. The data also were presented at EuroPCR 2024. “[O]ur findings suggest that to maximize symptom relief, more could be gained by focusing instead on identifying the symptoms that we can genuinely address with existing treatments.”

Arman Qamar, MD, MPH (Endeavor Health, Evanston, IL), who was not involved in the study, said that while there are effective tests for diagnosing CAD in symptomatic patients, those diagnostic tests have limitations.  

“Importantly, what they do not tell you is if the findings are contributing to the chest discomfort,” he told TCTMD. “It’s interesting, as we saw from ORBITA-2, many patients will continue to have symptoms. It could be that the lesions that were fixed or treated weren’t the cause. It’s possible the symptoms are noncardiac. It could also be microvascular disease. We would not expect these patients to benefit from coronary revascularization.”

In ORBITA-2, which was led by Rajkumar and senior investigator Rasha Al-Lamee, MBBS, PhD (Imperial College London), PCI was shown to be an effective antianginal treatment above and beyond the placebo effect. Despite being a positive study, nearly 60% of treated patients had residual symptoms.

Matching Symptoms

In ORBITA-STAR, which included 51 patients (mean age 62.9 years; 78.0% male) with stable angina and hemodynamically significant single-vessel CAD, investigators assessed the degree of similarity between experimentally induced ischemia with an angioplasty balloon and day-to-day symptoms. The protocol consisted of a balloon-occlusion and placebo-occlusion episode delivered in a randomized order and repeated four times. Each episode lasted 60 seconds and patients were told when it began and stopped but not told if it was the balloon-occlusion or placebo-occlusion episode.

After each episode, symptoms were assessed and rated on intensity and similarity scores (both scored on a scale of 0 to 10, with the higher number reflective of greater pain and degree of similarity to day-to-day symptoms).

The similarity score was a strong predictor of symptom improvement after PCI. At 12 weeks of follow-up, a patient with a symptom score of 5.25—the upper quartile—was significantly more likely to have less angina frequency (OR 8.01; 95% CI 2.39-15.86) than a patient with a similarity score in the lowest quartile (OR 1.31; 95% CI 0.71-1.99). Additionally, a higher similarity score was more likely to predict greater improvements in physical limitation, quality of life, and treatment satisfaction.

To TCTMD, Qamar said this is something he often sees in his own lab.

“When we’re doing the procedure and we inflate the balloon, we are always talking to the patient,” he said. “If they are having symptoms while we are working on the lesions, especially with inflated balloons and things like that, we feel reassured that we’re addressing, or have found, the main problem.”

Given the improvements in PCI, as well as the evidence from ORBITA-2 showing that PCI does help symptoms, Qamar said there is a need to improve the diagnostic technology, specifically in “trying to ascertain if the patient’s symptoms are related to the ischemia or the findings from the CT angiogram and stress testing.”

Performing an n-of-1 study on the cath lab table for everybody is not feasible, he said, noting that when operators are inflating a low-pressure balloon, they are generally committed to performing PCI. He highlighted a recent study from the ORBITA investigators showing the importance of characterizing angina phenotype. As reported by TCTMD, the researchers found that stable CAD patients who have angina with typical features are more likely than those who do not to achieve symptom relief from PCI.

“The nature of the symptoms is the best predictor of which patient is going to derive maximum benefit after coronary revascularization,” said Qamar, noting that this is something they assess in his hospital. With relatively simple tools, such as the Rose Angina Questionnaire and the Guideline-Based Typical Angina assessment, physicians can routinely assess patient symptoms to determine if they are likely to benefit from revascularization, said Qamar.  

In an editorial, Christina Lalani, MD, and Robert Yeh, MD (both from Beth Israel Deaconess Medical Center, Boston, MA), also say that greater attention to the nature or quality of a patient’s symptoms, as opposed to anatomical or physiologic measures, could help improve shared decision-making in those with stable CAD. “Against a background of rapidly changing technology, an important solution may be found simply in taking more careful histories from our patients,” they write.