Predicting PCI Benefits in cath lab: Study Validates Symptom Verification with Ischemic Stimulus

The similarity score strongly correlated with symptom improvement following PCI. The findings, published in the Journal of the American College of Cardiology, support the potential for individualized symptom mapping to optimize PCI targeting for patients most likely to experience benefits.

"Patients undergoing PCI for single-vessel CAD, whose symptoms validated through an ischemic balloon occlusion test, showed a higher likelihood of angina resolution during follow-up. Conversely, those whose induced pain or discomfort did not closely resemble their usual symptoms were more likely to experience persistent symptoms post-procedure," the researchers reported.

In stable CAD, 30% to 60% of patients remain symptomatic despite successful revascularization. Not all symptoms reported by a patient with myocardial ischemia may qualify as angina. Considering this, Christopher A. Rajkumar, Imperial College Healthcare NHS Trust, London, United Kingdom, and colleagues aimed to determine whether independent symptom verification using a placebo-controlled ischemic stimulus could distinguish which patients achieve the greatest symptom relief from PCI.

The research team performed a multicenter, n-of-1, placebo-controlled study (ORBITA-STAR) in patients undergoing single-vessel PCI for stable symptoms.

Participants experienced four episodes (each lasting 60 seconds) of low-pressure balloon occlusion across their coronary stenosis, randomly alternating with four episodes of placebo inflation.

After each episode, patients assessed how closely the induced symptom matched their usual symptom. The similarity score ranged from −10 (indicating the placebo replicated the symptom more closely than balloon occlusion) to +10 (indicating balloon occlusion exactly replicated the symptom). The primary goal was to determine whether the similarity score could predict symptom relief following PCI.

The researchers reported the following findings:

• Fifty-one patients were recruited, aged 62.9 ± 8.6 years. The median fractional flow reserve was 0.68, and the instantaneous wave-free ratio was 0.80.
• The median similarity score was 3.
• The similarity score was a strong predictor of symptom improvement following PCI: a patient with an upper quartile similarity score of 5.25 was significantly more likely to have lower angina frequency at follow-up (OR: 8.01) than a patient with a lower quartile similarity score of 0.875 (OR: 1.31).

To conclude, in the investigation involving symptomatic patients referred for PCI of single-vessel coronary stenosis, using placebo-controlled symptom verification with balloon occlusion proved highly predictive of symptom improvement following PCI. Tailoring therapy based on symptom verification in stable CAD holds promise for optimizing PCI benefits, targeting patients likely to derive the greatest benefit while potentially mitigating risks associated with unnecessary revascularization in non-responsive patients.

Reference:

Rajkumar CA, Foley MJ, Ahmed-Jushuf F, Simader FA, Mohsin M, Ganesananthan S, Nowbar AN, Chotai S, Sen S, Petraco R, Nijjer SS, Sehmi J, Ruparelia N, Dungu JN, Kabir A, Tang K, Gamma R, Davies JR, Kotecha T, Cole GD, Howard JP, Keeble TR, Clesham G, O'Kane PD, Harrell FE Jr, Francis DP, Shun-Shin MJ, Al-Lamee RK. N-of-1 Trial of Angina Verification Before Percutaneous Coronary Intervention. J Am Coll Cardiol. 2024 Jul 2;84(1):1-12. doi: 10.1016/j.jacc.2024.04.001. Epub 2024 May 14. PMID: 38752902.