Thoracic Epidural Reduces Risks of Increased Left Ventricular Mass Index During Coronary Artery Bypass Graft Surgery

Background: Increased left ventricular mass index (LVMI) results from aortic valve lesions as an adaptive mechanism to help limit systolic wall stress and preserve ejection fraction (EF).

Aim: to investigate the effects of sympathetic blockade by HTEA on systolic and diastolic LV function in patients undergoing aortic valve replacement (AVR) alone or in addition to coronary artery bypass graft (CABG).

Design: A prospective randomized controlled comparative study. Methods: Eighty patients received either general anesthesia ( control group n=40) or with high thoracic epidural analgesia(HTEA group n=40). Each group subdivided to normal (LVM) (n=20)or increased(LVM) group(n=20), all submitted to (AVR) alone or in addition to (CABG).Perioperative heart rate (HR), mean arterial blood pressure (MAP), incidence of ischemic ECG, LV systolic and diastolic function changes were measured till 48 h, postoperatively.

Patients were subjected to ambulatory Holter monitoring, Hemodynamic measures, intraoperative transesophageal echocardiography (iTEE) and postoperative Trans Thoracic Echocardiography (TTE) to assess myocardial ischemia and Left ventricular systolic/diastolic function.

Inclusion criteria

• patients between 65 and 75 years with:
• physical status of ASA II and IV
• who underwent aortic valve replacement (for isolated or mixed aortic valve lesions) alone or in addition to-coronary artery bypass grafting. in the Cardio-thoracic Surgery Department of Tanta University Hospital during a two year period were enrolled in this study.
• Before inclusion in the study, all patients were evaluated with extended echocardiographic imaging, full history including cardiac symptoms (dyspnea, orthopnea, paroxysmal nocturnal dyspnea, chest pain, and low cardiac output symptoms) was taken from all patients. General (including body weight and height) and systematic (including cardiac examination) examinations were done to all patients.

Exclusion criteria

• Patients with an ejection fraction of 0.3, myocardial infarction within the last 4 weeks
• diabetes
• severe pulmonary or arterial hypertension.
• a contraindication for HTEA.
• patients without preoperative optimal echocardiographic imaging were excluded.
• Among the exclusion criteria were the administration of ticlopidine within 15 days before surgery and the administration of platelet glycoprotein IIb/IIIa inhibitors. In common with previous investigators, we did not consider treatment with low-molecular-weight heparin and aspirin below the dosage of 160 mg/day to be contraindications to the procedure.
• Patients with significant aortic insufficiency were also excluded from the study in order to avoid introducing further variables that could influence hemodynamic response to the procedure.
• Patients were excluded if they underwent an AVR on an emergency basis, had poor acoustic windows for adequate echocardiographic assessment, and/or did not undergo an echocardiogram before the operation.