Percutaneous Left Ventricular Unloading During High-Risk Coronary Intervention: Rationale and Design of the CHIP-BCIS3 Randomized Controlled Trial

Abstract

Introduction: Percutaneous coronary intervention for complex coronary disease is associated with a high risk of cardiogenic shock. This can cause harm and limit the quality of revascularization achieved, especially when left ventricular function is impaired at the outset. Elective percutaneous left ventricular unloading is increasingly used to mitigate adverse events in patients undergoing high-risk percutaneous coronary intervention, but this strategy has fiscal and clinical costs and is not supported by robust evidence.

Methods: CHIP-BCIS3 (Controlled Trial of High-Risk Coronary Intervention With Percutaneous Left Ventricular Unloading) is a prospective, multicenter, open-label randomized controlled trial that aims to determine whether a strategy of elective percutaneous left ventricular unloading is superior to standard care (no planned mechanical circulatory support) in patients undergoing nonemergent high-risk percutaneous coronary intervention. Patients are eligible for recruitment if they have severe left ventricular systolic dysfunction, extensive coronary artery disease, and are due to undergo complex percutaneous coronary intervention (to the left main stem with calcium modification or to a chronic total occlusion with a retrograde approach). Cardiogenic shock and acute ST-segment-elevation myocardial infarction are exclusions. The primary outcome is a hierarchical composite of all-cause death, stroke, spontaneous myocardial infarction, cardiovascular hospitalization, and periprocedural myocardial infarction, analyzed using the win ratio. Secondary outcomes include completeness of revascularization, major bleeding, vascular complications, health economic analyses, and health-related quality of life. A sample size of 250 patients will have in excess of 80% power to detect a hazard ratio of 0.62 at a minimum of 12 months, assuming 150 patients experience an event across all follow-up.

Conclusions: To date, 169 patients have been recruited from 21 National Health Service hospitals in the United Kingdom, with recruitment expected to complete in 2024.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05003817.

Keywords: coronary artery disease; heart-assist devices; left ventricular systolic dysfunction; percutaneous coronary intervention; randomized controlled trial.

Figure 1.

Contemporary guidelines on the use of mechanical circulatory support in high-risk percutaneous coronary intervention (PCI). The National Institute for Health and Care Excellence guideline committee does not provide a summary estimate of the level of evidence but acknowledged the lack of high-quality evidence. B-R indicates level of evidence B, one or more randomized trials; N/A, not available; and UK, United Kingdom.

Figure 2.

Trial organization. LSHTM indicates London School of Hygiene & Tropical Medicine.

Figure 3.

Inclusion criteria for CHIP-BCIS3 (Controlled Trial of High-Risk Coronary Intervention With Percutaneous Left Ventricular Unloading). BCIS indicates British Cardiovascular Intervention Society; LVEF, left ventricular ejection fraction; PCI, percutaneous coronary intervention; and SYNTAX, Synergy Between PCI With Taxus and Cardiac Surgery.

Figure 4.

CHIP-BCIS3 (Controlled Trial of High-Risk Coronary Intervention With Percutaneous Left Ventricular Unloading) flowchart. BCIS-JS indicates British Cardiovascular Intervention Society Jeopardy Score; CAD, coronary artery disease; LV, left ventricle; and PCI, percutaneous coronary intervention. *Severe LV dysfunction is defined as an LV ejection fraction ≤35% or ≤45% in the presence of severe mitral regurgitation.

Figure 5.

Definitions of periprocedural myocardial infarction in CHIP-BCIS3 (Controlled Trial of High-Risk Coronary Intervention With Percutaneous Left Ventricular Unloading). Specific definitions for participants where baseline high-sensitivity cardiac troponin (hs-cTn) is lower than the upper reference limit (URL; left), above the URL and stable or falling (middle), or above the URL and rising (right).

Figure 6.

The win ratio. Theoretical pair of participants in CHIP-BCIS3 (Controlled Trial of High-Risk Coronary Intervention With Percutaneous Left Ventricular Unloading). In this example, neither participant died or experienced a stroke or spontaneous myocardial infarction (MI). Both patients had a cardiovascular (CV) hospitalization, and as participant X had fewer of these events, they are declared the winner. Periprocedural MI is not considered, as at least 1 participant in the pair experienced a more significant event. LV indicates left ventricle.