RESUMO
To assess right ventricular functions by echocardiography in patients with proximal right coronary artery (RCA) CTO and correlating it with clinical and angiographic variables. We studied 60 consecutive patients with CTO of the proximal RCA and no other significant lesions in the left coronary system. Echocardiography was performed in order to measure left ventricular (LV) dimensions, LVEF, RV end diastolic area (RVEDA), RV end systolic area (RVESA), RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), Doppler myocardial performance index (MPI), trans-tricuspid E and A waves, E/A ratio, S', e' and a'. Grades of coronary collaterals was assessed. Doppler MPI showed negative correlation with TAPSE (r = -0.8997, p < 0.0001) and RVFAC (r = -0.928, p < 0.0001). Positive correlation with trans-tricuspid E/A ratio (r = 0.893, p < 0.0001) and E/e' ratio (r = 0.783, p < 0.0001). Patients with no evidence of MI had more well-developed (grade 3) coronary collaterals (83.8 vs. 17.4 %). Patients with evidence of MI had lower RVFAC 38.13 ± 5.39 versus 45.08 ± 4.99 % (p < 0.0001), lower TAPSE 20.17 ± 3.85 versus 25.35 ± 3.46 mm (p < 0.0001), higher MPI 0.4 ± 0.08 versus 0.31 ± 0.05 (p < 0.0001), higher trans-tricuspid E/A ratio 1.79 ± 0.38 versus 1.13 ± 0.36 (p < 0.0001) and E/e' ratio 5.23 ± 1.02 versus 3.61 ± 0.88 (p < 0.0001). Patients with poorly developed collaterals had lower TAPSE and RVFAC and a higher MPI (p < 0.0001 for each). Patients with proximal RCA CTOs and evidence of inferior wall MI have significant impairment of RV functions in addition to poorly developed coronary collaterals. Those with proximal RCA CTOs and well-developed coronary collaterals have better RV functions.