Drug-Coated Balloon Only Strategy After Recanalization of Chronic Total Coronary Occlusions

Difference between the minimal luminal diameter measured by quantitative coronary angiography immediately after the index procedure and the minimal luminal diameter at nine-month follow-up angiography. This is the sole endpoint against which the pre-specified performance goal of 0.50 mm is formally tested, using the upper bound of the one-sided 97.5% confidence interval, in the per-protocol population.

Proportion of enrolled, successfully recanalized lesions treated exclusively with a drug-coated balloon without bailout stent implantation, defined consistent with Drug-Coated Balloon Academic Research Consortium recommendations and calculated on the full intention-to-treat denominator. Reported descriptively with an exact Clopper-Pearson 95% confidence interval; not hypothesis-tested against a performance goal.

Late lumen loss measured across the analysis segment including the 5 mm proximal and distal margins adjacent to the treated segment, reported as a supportive quantitative coronary angiography measure.

Quantitative flow ratio (QFR) derived by the frame-count contrast-flow method from at least two angiographic projections separated by 25 degrees or more, with intracoronary nitrate administered before each acquisition, compared between the post-procedural baseline and nine-month follow-up. Exploratory and hypothesis-generating.

Unit of Measure: ratio

Percent diameter stenosis of 50% or greater within the in-balloon analysis segment at follow-up angiography, defined consistent with Drug-Coated Balloon Academic Research Consortium (DCB-ARC) recommendations and reported as a proportion of lesions with a 95% confidence interval.

Unit of Measure: percentage of lesions

Percent diameter stenosis of 50% or greater within the in-segment analysis segment, which includes the 5 mm proximal and distal margins adjacent to the treated segment, at follow-up angiography, defined consistent with Drug-Coated Balloon Academic Research Consortium (DCB-ARC) recommendations and reported as a proportion of lesions with a 95% confidence interval.

Unit of Measure: percentage of lesions

Complete occlusion of the target lesion, defined as 100% diameter stenosis with TIMI 0 antegrade flow at follow-up angiography, reported as a proportion with 95% confidence interval.

Any clinically driven repeat revascularization of the target lesion, percutaneous or surgical, reported as a proportion with 95% confidence interval.

Any clinically driven repeat revascularization of the target vessel outside the target lesion, reported as a proportion with 95% confidence interval.

Minimal lumen area within the treated segment measured by IVUS at matched anatomical cross-sections, compared between the immediate post-procedure acquisition and nine-month follow-up.

External elastic membrane cross-sectional area measured by intravascular ultrasound (IVUS) at matched anatomical cross-sections within the treated segment, compared between the immediate post-procedure acquisition and nine-month follow-up. Together with the vascular remodeling index this forms the mechanistic centerpiece of the study, testing whether an exclusive drug-coated balloon strategy preserves the vessel's capacity for positive remodeling.

Unit of Measure: square millimeters (mm^2)

Ratio of the external elastic membrane cross-sectional area at nine-month follow-up to the external elastic membrane cross-sectional area immediately after the index procedure, measured by intravascular ultrasound (IVUS) at matched anatomical cross-sections. Values above 1.0 indicate positive remodeling and values below 1.0 indicate negative remodeling.

Unit of Measure: ratio

Plaque plus media cross-sectional area divided by external elastic membrane cross-sectional area, measured by intravascular ultrasound (IVUS) at matched anatomical cross-sections within the treated segment, compared between the immediate post-procedure acquisition and nine-month follow-up. Reported as the absolute change in percentage points.

Unit of Measure: percentage of external elastic membrane area

Volumetric percent atheroma volume across the treated segment, calculated as the sum of plaque plus media areas divided by the sum of external elastic membrane areas across all analyzed cross-sections, measured by intravascular ultrasound (IVUS) and compared between the immediate post-procedure acquisition and nine-month follow-up. Reported as the absolute change in percentage points.

Unit of Measure: percentage of total vessel volume

Change from baseline in the Physical Limitation domain of the Seattle Angina Questionnaire (SAQ), which measures the degree to which angina restricts physical activities. The Seattle Angina Questionnaire is a 19-item disease-specific instrument for coronary artery disease. Each domain is scored from 0 to 100, where 0 is the worst possible and 100 the best possible status; higher scores indicate a better outcome. Change from baseline is reported, so positive values indicate improvement.

Change from baseline in the Angina Stability domain of the Seattle Angina Questionnaire (SAQ), which measures the change in angina frequency relative to four weeks earlier. The Seattle Angina Questionnaire is a 19-item disease-specific instrument for coronary artery disease. Each domain is scored from 0 to 100, where 0 is the worst possible and 100 the best possible status; higher scores indicate a better outcome. Change from baseline is reported, so positive values indicate improvement.

Change from baseline in the Angina Frequency domain of the Seattle Angina Questionnaire (SAQ), which measures how often angina and nitroglycerin use occur. The Seattle Angina Questionnaire is a 19-item disease-specific instrument for coronary artery disease. Each domain is scored from 0 to 100, where 0 is the worst possible and 100 the best possible status; higher scores indicate a better outcome. Change from baseline is reported, so positive values indicate improvement.

Change from baseline in the Treatment Satisfaction domain of the Seattle Angina Questionnaire (SAQ), which measures satisfaction with the explanation and management of angina. The Seattle Angina Questionnaire is a 19-item disease-specific instrument for coronary artery disease. Each domain is scored from 0 to 100, where 0 is the worst possible and 100 the best possible status; higher scores indicate a better outcome. Change from baseline is reported, so positive values indicate improvement.

Change from baseline in the Angina-Related Quality of Life domain of the Seattle Angina Questionnaire (SAQ), which measures the perceived impact of angina on enjoyment of life. The Seattle Angina Questionnaire is a 19-item disease-specific instrument for coronary artery disease. Each domain is scored from 0 to 100, where 0 is the worst possible and 100 the best possible status; higher scores indicate a better outcome. Change from baseline is reported, so positive values indicate improvement.

Number of participants experiencing the composite of all-cause death, myocardial infarction, or stroke. Death is classified as cardiovascular or non-cardiovascular where possible; myocardial infarction is defined by the Fourth Universal Definition and includes procedural type 4a and spontaneous events; stroke includes ischemic and hemorrhagic events. The reported value is the number of participants with at least one component event; individual components are reported as separate categories within this measure.

Number of participants experiencing a bleeding event classified according to Bleeding Academic Research Consortium (BARC) criteria. The reported value is the number of participants with any BARC type 1 through 5 bleeding event; events are reported as separate categories for major bleeding (BARC type 3 or 5), clinically relevant non-major bleeding (BARC type 2), and minor bleeding (BARC type 1).

Number of participants developing acute kidney injury as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria, assessed after the index procedure and after the nine-month follow-up angiography. Cumulative contrast volume across both procedures is recorded.