Off-Pump Right-Sided Minimally Invasive Direct Coronary Artery Bypass using the Right Internal Mammary Artery to the Right Coronary Artery: A Case Report.

BACKGROUND: Minimally Invasive Direct Coronary Artery Bypass (MIDCAB) is usually performed through a left-sided approach; however, in carefully selected patients, right-sided MIDCAB (r-MIDCAB) may provide an alternative surgical approach for isolated right coronary artery disease. In this case, the Right Internal Mammary Artery (RIMA) was used as an in situ graft to the Right Coronary Artery (RCA). CASE PRESENTATION: We report a 65-year-old man with a history of inferior myocardial infarction treated with two RCA stents in 2015. Recurrent anginal symptoms developed in 2024 despite medical therapy. Coronary angiography demonstrated a severely calcified, tortuous subocclusive RCA lesion immediately distal to the previously stented segment. Repeat PCI was unsuccessful because the lesion could not be crossed. Following multidisciplinary Heart Team evaluation, off-pump r-MIDCAB was performed through a right mini-thoracotomy using an in situ RIMA-to-RCA graft. Transit-Time Flow Measurement (TTFM) showed a mean graft flow of 25 mL/min, pulsatility index of 1.6, diastolic filling of 54%, and backflow of 0.1%. At five-month follow-up, CT coronary angiography demonstrated a patent graft with good distal runoff. CONCLUSION: This case demonstrates the technical feasibility of RIMA-to-RCA revascularization via a right mini-thoracotomy in a carefully selected patient with isolated RCA disease that is unsuitable for PCI. The short-term clinical and imaging findings were favorable; however, a single case with five months of follow-up cannot establish safety, effectiveness, or long-term graft durability. Larger studies with longer follow-up are required.