Coronary Laser in Undilatable or Uncrossable Lesions

Inclusion Criteria: * Patients aged over 18 years. * Patients with either stable coronary artery disease or acute coronary syndromes as the clinical presentation. * Patients with severe coronary lesions (\>70% by visual estimation) in native vessels or coronary bypass grafts. * "Uncrossable" coronary lesions (i.e., lesions that cannot be crossed with a 0.7:1 balloon after successful guidewire passage) or "Undilatable" lesions (i.e., those in which balloon dilation with a 1:1 non-compliant balloon at 18 atm results in less than 80% expansion relative to the distal reference vessel diameter; this group includes both de novo lesions and in-stent restenosis or underexpanded stents). Exclusion Criteria: * Patients with known allergies to aspirin (ASA), clopidogrel, prasugrel, or ticagrelor. * Patients unable to provide informed consent, either personally or through a legal representative. * Patients with clinical or hemodynamic instability defined as: sustained hypotension (systolic blood pressure ≤ 90 mmHg for ≥ 30 minutes or use of pharmacological and/or mechanical support to maintain an SBP ≥90 mmHg) or evidence of end-organ hypoperfusion including urine output of \<30 mL/h, cool extremities, altered mental status, and/or serum lactate \>2.0 mmol/L. * Patients with significant comorbidities and a life expectancy of less than one year.