Transesophageal echocardiography evaluation of the thoracic aorta.

Transesophageal echocardiography (TEE) can be used to identify risk factors such as aortic atherosclerosis[2] before any sort of surgical manipulations involving aorta and its related structures. TEE has become an important noninvasive tool to diagnose acute thoracic aortic pathologies. TEE evaluation of endoleaks helps early detection and immediate corrective interventions. TEE is an invaluable imaging modality in the management of aortic pathology. TEE has to a large extent improved the patient outcomes.

Transesophageal echocardiography estimation of coronary sinus blood flow for the adequacy of revascularization in patients undergoing off-pump coronary artery bypass graft.

Aims and Objectives: Physiologically coronary sinus (CS) drains the left coronary artery (LCA) territory. Stenosis of the branches of LCA may decrease the coronary sinus blood flow (CSBF). Any intervention that aims at restoring the flow of the stenosed vessel increases coronary artery flow that should consequently increase the CSBF. Hence, this study was undertaken to assess the CSBF before and after each branch of LCA to determine the adequacy of surgical revascularization in patients undergoing elective off pump coronary artery bypass grafting (OPCAB) using transesophageal echocardiography (TEE). Materials and Methods: Thirty consecutive patients scheduled for elective OPCAB were enrolled. CSBF was assessed before and after each branch of LCA revascularization using TEE. Left internal mammary artery (LIMA) Doppler was also obtained post LIMA to left anterior descending (LAD) grafting. Results: Hemodynamic and echocardiographic variables were compared by means of Student’s t-test for paired data before and after revascularization. The CSBF per beat (1.28 ± 0.71), CSBF per minute (92.59 ± 59.32) and total velocity time integral (VTI) (8.93 ± 4.29) before LAD grafting showed statistically significant increase to CSBF per beat (1.70 ± 0.89), CSBF per minute (130.72 ± 74.22) and total VTI (11.96 ± 5.68) after LAD revascularization. The CSBF per beat (1.67 ± 1.03), CSBF per minute (131.91 ± 86.59) and total VTI (11.00 ± 5.53) before obtuse marginal (OM) grafting showed statistically significant increase to CSBF per beat (1.91 ± 1.03), CSBF per min (155.20 ± 88.70) and total VTI (12.09 ± 5.43) after OM revascularization. In 9 patients, color flow Doppler of LIMA could be demonstrated which showed diastolic predominant blood flow after LIMA to LAD grafting. Conclusion: Demonstration of CSBF was simple and monitoring the trend of CSBF values before and after each graft of LCA territory will guide to determine the adequacy of surgical revascularization.

Exploration of the Angiogenic Potential of Honey.

Aims: The present study was conducted to confirm the angiogenic potential of honey using Chick Chorioallantoic Membrane (CAM), an in ovo model and to study its effect on Vascular Endothelial Growth Factor (VEGF) expression in the CAM tissue. Attempts were also made to identify the probable active constituents present in honey that contributed to its angiogenic potential. Methodology: Honey was evaluated over concentrations ranging from 0.015 to 25% v/v and the extent of angiogenesis was quantified using stereomicroscopy. VEGF expression at transcript level was determined by RT-PCR. Erythropoietin and Heparin were used as positive and negative controls respectively. Four known constituents of honey viz., Glucose, Proline, Vitamin C and Hydrogen peroxide were tested by biochemical methods. Results: New blood formation was seen at all the concentrations tested, however the proangiogenic effect was greater at lower concentrations. These results were significantly greater than that seen with erythropoietin, the positive control. VEGF mRNA expression in CAM tissue also demonstrated similar findings. Among the constituents tested, Vitamin C and Hydrogen peroxide were observed to be associated with the angiogenic effect of honey. Conclusion: The study thus confirms the pro-angiogenic potential of honey at low concentrations. This effect is probably due to the presence of Hydrogen peroxide and Vitamin C and is mediated via alteration in VEGF expression.

Utility of pulmonary venous flow diastolic deceleration time in an adult patient undergoing surgical closure of atrial septal defect and coronary artery bypass grafting.

Acute left ventricular (LV) failure has been reported after surgical closure of atrial septal defect (ASD) in adult patients. We report acute LV failure in a 56 year old gentleman following coronary artery bypass grafting (CABG) and surgical closure of ASD. Transesophageal echocardiography examination of the patient following closure of ASD and CABG showed a residual ASD and a shunt (Qp :Qs = 1.5). The residual ASD was closed after re-institution of cardiopulmonary bypass (CPB) under cardioplegic cardiac arrest. However, the patient did not tolerate closure of the residual ASD. The CPB was re-established and under cardioplegic cardiac arrest residual ASD was reopened to create a fenestration. This time patient was weaned easily from CPB. Postoperatively, 16 hours after extubation, patient became hemodynamically unstable, the patient was electively put on ventilator and intra-aortic balloon pump. Later the patient was weaned off successfully from ventilator. Retrospective analysis of pulmonary venous flow diastolic deceleration time (PVDT D ) recorded during prebypass period measured 102 msec suggestive of high left atrial pressure which indicate possibility of LV failure after ASD closure.

Comparison of simultaneous estimation of cardiac output by four techniques in patients undergoing off-pump coronary artery bypass surgery--a prospective observational study.

We prospectively compared four techniques of cardiac output measurement: bolus thermodilution cardiac output (TDCO), continuous cardiac output (CCO), pulse contour cardiac output (PiCCO), and Flowtrac (FCCO), simultaneously in fifteen patients undergoing off-pump coronary artery bypass grafting (OPCAB). All the patients received pulmonary artery catheter (capable of measuring both bolus thermodilution cardiac output and CCO), PiCCO arterial cannula in the left and FCCO in the right femoral artery. Cardiac indices (CI) were obtained every fifteen minutes by using all the four techniques. TDCO was treated as 'control' and the rest were treated as 'test' values. Interchangeability of techniques with TDCO was assessed by Bland and Altman plotting and mountain plot. Four hundred and thirty eight sets of data were obtained from fifteen patients. The values of cardiac output varied between 1 to 6.9 L/min. We found that the values of all the techniques were interchangeable. At certain times, the values of CI measured by both PiCCO and FCCO appeared erratic. The values of CI measured simultaneously appeared in the following descending order of accuracy; TDCO>CCO>FCCO>PiCCO (the % times TDCO correlated with CCO, FCCO, PiCCO was 93, 86 and 80 respectively). The bias and precision (in L/min) for CCO were 0.03, 0.06, PiCCO 0.13, 0.1 and flowtrac 0.15, 0.04 respectively suggesting interchangeability. We conclude that the cardiac output measured by CCO technique and the pulse contour as measured by PiCCO and FCCO were interchangeable with TDCO more than 80% of the times.

Conscious off-pump coronary artery bypass surgery.

BACKGROUND: Cardiothoracic surgery has been previously performed successfully under thoracic epidural anesthesia alone. Between October 2001 and December 2003, we performed 123 conscious off-pump coronary artery bypass surgeries using epidural anesthesia as the sole anesthetic. This technique is an alternative to cardiothoracic surgery performed under general anesthesia. Certain modifications in the technique facilitate the process. METHODS AND RESULTS: There were 24 female patients and 99 male patients with mean age of 58.6 +/- 6.2 years; 12 patients underwent repeat coronary artery bypass surgery. All the patients underwent epidural catheterization on the evening before surgery. Out of the 123 patients scheduled for coronary artery bypass graft surgery, 120 underwent off-pump coronary artery bypass graft surgery successfully; 4 patients underwent off-pump surgery via left thoracotomy and the rest through mid sternotomy. These patients received 295 grafts in all (single graft in 26 patients, double in 42 patients, triple in 35 patients, and quadruple in 20 patients). Three patients required conversion to general anesthesia and one to cardiopulmonary bypass. There was no mortality in the group. CONCLUSIONS: Our experience suggests that by modifying the surgical techniques, we can accomplish conscious coronary artery bypass surgery.