Off pump coronary revascularization is an old technique performed first in St Petersburg in 1964, Off pump coronary artery surgery has been developed following two different approaches. Minimally invasive direct-access coronary artery bypass (MIDCAB) that consists of anastomosing the left internal mammary artery to the left anterior descending coronary artery through small anterior left thoracotomy, The second approach is multi-vessel grafting without CPB performed through standard median sternotomy. Dexmedetomidine (Dex), a highly selective α2-adrenergic receptor agonist, is widely used for sedation and analgesia in the ICU or as an anesthetic adjuvant.~This study will be a prospective comparative controlled randomized double blinded clinical trial on 36 patients divided into control ,and dexmedetomidine group.
the study will assess the impact of intraoperative dexmedetomidine infusion on myocardial performance by investigating the left ventricular (LV) systolic and diastolic function and right ventricular (RV) fraction area change (which reflect RV systolic function) using two-dimensional trans-esophageal echocardiography (TEE) in patients undergoing elective first-time isolated off-pump coronary artery bypass (OPCAB) grafting. LV Systolic function will be measured by the TEE via the fractional area change, fraction shortening, and ejection fraction.