Minimally Invasive Direct Coronary Artery Bypass Surgery Under High Thoracic Epidural

摘要

Thoracic epidural analgesia is a well-established technique that provides intense intra and postoperative pain control after cardiothoracic surgery. Over the past several years high-thoracic epidural anesthesia (hTEA) has emerged as a potentially beneficial supplement to general anesthesia in patients undergoing cardiac surgery (1,2). Along with superior pain control (3), thoracic epidural analgesia with local anesthetics blocks cardiac sympathetic nerve activity and effectively inhibits the myocardial stress response associated with surgical procedures (4). Furthermore, cardiac sympathectomy decreases determinants of myocardial oxygen demand (5), beneficially affects myocardial blood flow (6,7), improves left ventricular function (8), and reduces thrombotic-related complications (9). Although the effectiveness of hTEA for thoracoscopic procedures (10) and mini-thoracotomy (11) has been reported in the literature, these procedures usually require the addition of endotracheal intubation. In July 2000, Karagoz et al. (11) reported the first successful coronary artery grafting using only a regional anesthetic technique. Under hTEA, this group was able to perform mini-thoracotomy and using a short segment of radial artery inserted a jump-graft between the internal thoracic artery and the left anterior descending artery (LAD). We hypothesized that hTEA could be used for mini-thoracotomy and minimally invasive direct coronary artery bypass (MID-CAB) with left internal mammary artery (LIMA) mobilization and direct grafting to LAD. We report a case of a MID-CAB that was managed with hTEA. Case Report A 53-yr-old man (weight 94 kg, height 178 cm) presented to the operating room (OR) for MID-CAB surgery as a result of a high-grade complex LAD lesion. Cardiac catheterization 2 days earlier showed LAD 95% lesion, LCx (left circumflex) 95% lesion, and distal RCA (right coronary artery) with 100% occlusion. Successful angioplasty and stent placement were performed to the LCx and RCA at the time of catheterization. The left ventricular ejection fraction was estimated at 60%. His medical history was significant for hypertension, hypercholesteremia, and peptic ulcer disease. The patient had a history of cigarette smoking (1 pack per day for 25 yr) and pulmonary function testing showed forced vital capacity of 4.8 L (89% predicted) and forced expiratory volume (1 s) of 2.6 L (74% predicted). The patient coagulation profile indicated a partial thromboplastin time 32.6 s, prothrombin time 13.1 s, international normalized ratio 1.0, and platelet count 253 K/mm (3). The patient was fully informed and understood all the risks and alternatives to the proposed anesthetic technique. IRB-approved informed consent was obtained from the patient for the MID-CAB procedure using hTEA with option for general anesthesia as a backup technique in case of patient discomfort or hemodynamic instability. In the OR after standard monitoring (heart rate [HR] 82 bpm, blood pressure [BP] 93/51 mm Hg, oxygen saturation [SaO2] 99%) and IV catheters were established, a 17-gauge Tuohy needle was used to localize the epidural space at the T1/2 interspace using a midline loss-of-resistance technique with the patient in the sitting position. A 19-gauge epidural catheter was then inserted 3 cm into the epidural space, and a test dose (3 mL 1.5% lidocaine with epinephrine 1:200,000) was administered to eliminate intravascular or intrathecal placement. The patient was then returned to the supine position and hemodynamic monitoring devices were placed, including a pulmonary artery catheter. Over the next 30 min, epidural anesthesia was established using carefully titrated small boluses of mixed local anesthetic solution (20 mL bupivacaine 0.5%, 20 mL of lidocaine 2%, and 5 mL fentanyl 0.005%) delivered in sequential 3–5 mL boluses (total 15 mL). The objective of this approach was to achieve both somatosensory (assessed by temperature and pinprick discrimination) and motor block (a