Staged Intervention Safe and Effective for Complex Chronic Total Occlusions PCI: INVEST-CTO Trial, TCT 2025

The INVEST-CTO study is a prospective, single-arm, international, multicenter trial evaluating whether a planned two-stage intervention could improve technical success and safety in complex CTOs, a subgroup in which PCI success has historically been low and complication rates high. A total of 150 patients were enrolled based on predetermined high-risk anatomical criteria, with adjudication by both an angiographic core laboratory and a clinical events committee.

Patients first underwent an “investment procedure,” consisting of balloon modification of the CTO segment without attempts at wire crossing, re-entry, or retrograde techniques. After 8–12 weeks, they returned for a planned completion PCI, performed at operator discretion. The primary endpoint was procedural success, defined as technical success with no in-hospital MACE, including death, myocardial infarction, or clinically driven target vessel revascularization (TVR).

Among 151 evaluable patients, cumulative procedural success was 86.7% (95% CI 80.3–91.7%), with identical rates for technical success. There were no in-hospital MACE events. Secondary analyses showed procedural success increased to 90.1% when partial technical success was included, and to 93.4% after a second attempt when required. The 30-day composite safety endpoint occurred in 4.6% of patients, including one death, one spontaneous MI, one stroke, one tamponade, two bleeding events (BARC ≥3), and one retained PCI device.

Baseline characteristics reflected a high-risk population: median age 66 years, 85% male, 42% prior MI, 28% diabetes, and 19.6% with chronic kidney disease (eGFR <60 mL/min/1.73 m²). Lesions were highly complex, with a mean J-CTO score of 3.4, 81.7% exceeding 20 mm in length, 80.4% with an ambiguous proximal cap, and severe calcification in 44.4%. 

Procedural burden remained low during the investment procedure, with median radiation exposure of 550 mGy, contrast use of 100 mL, and a 61-minute median duration. These increased during the completion PCI, as expected, with 1058 mGy radiation, 140 mL contrast, and 124-minute median duration.

Investigators noted that CTO PCI is often deferred due to low success rates and high complication risk when attempted in a single session. The findings support a staged approach as a safe and effective strategy in anatomically complex occlusions, particularly in experienced CTO centers.