The sham effect of invasive interventions in chronic coronary syndromes: a systematic review and meta-analysis

• Published in: BMC cardiovascular disorders Vol. 22; no. 1; p. 223
• Main Authors: Palma, Catarina, Antunes David, Cláudio Virgílio, Fernandes, Ricardo, Pinto, Fausto J., Costa, João, Ferreira, Joaquim J, Caldeira, Daniel
• Format: Journal Article
• Language: English
• Published: England Springer Nature 14.05.2022; BioMed Central Ltd; BioMed Central; BMC
• Subjects: Angina; Angina pectoris; Bias; Cardiac stress tests; Cardiovascular disease; Care and treatment; Chronic coronary syndromes; Clinical trials; Confidence intervals; Coronary vessels; Data collection; Evaluation; Heart diseases; Heart failure; Intervention; Invasive treatment; Meta-analysis; Patients; Placebo effect; Quality of life; Sensitivity analysis; Sham effect; Sham procedure; Software reviews; Systematic review; Therapeutics, Experimental; Portugal; Sham effect; Chronic coronary syndromes; Sham procedure; Invasive treatment
• ISSN: 1471-2261; 1471-2261
• DOI: 10.1186/s12872-022-02658-x

© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativeco mmons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Background: Some patients with chronic coronary syndromes undergo invasive procedures but the efficacy of such interventions remains to be robustly established by randomised sham-controlled trials (RCTs). Purpose: To determine the sham effect in patients with chronic coronary syndromes enrolled in RCTs by performing a systematic review and meta-analysis. Methods: In April 2022, we performed a literature search for published patient-blind RCTs (CENTRAL, MEDLINE®, PsycINFO, and reference lists) with sham procedures, reporting the pre-post effects in the invasive sham arm among patients with Canadian cardiovascular society (CCS) angina or angina equivalents. Results: 16 RCTs were included with 546 patients in the sham arm. Pooled results showed that sham interventions were associated with: improvement of 7% (95% CI 2-11%; I2 = 0%) in exercise time; decrease of 0.78 (95% CI - 1.10 to - 0.47; I2 = 75%) in CCS angina class; decrease of 53% (95% CI 24-71%; I2 = 96%) and 25% (95% CI 20-29%; I2 = 0%) in anginal episodes and nitroglycerine (NTG) use, respectively. Pooled results also showed an improvement in the physical functioning, angina frequency, treatment satisfaction, and disease perception domains of the Seattle Angina Questionnaire (SAQ). Conclusion: Sham interventions in patients with chronic coronary syndromes were associated with a significant decrease in anginal episodes, NTG use, and CCS angina class and increased SAQ quality of life and exercise time. These results highlight the need for previous non sham-controlled trials to be interpreted with caution, and the importance of new invasive interventions to be evaluated versus a sham procedure.