DK2985_C000 1..28 - AlSharqia Echo Club

474 Transesophageal Echocardiography(A)(B)ATRIALANASTOMOSISLAAoLVRVFigure 20.4 Mid-esophageal long-axis view of a 47-year-old man after cardiac transplantation. Note the flow acceleration in the leftventricular outflow tract upon weaning from cardiopulmonary bypass. Aliasing was also present at the level of the mitral valve most likelyfrom the compressing effect of the edematous atrial anastomosis. This may simulate cor triatriatum (Ao, aorta; LA, left atrium; LV, leftventricle; RV, right ventricle).vascular resistance (PVR) .480 dyne s/cm 5 or 6 Woodunits, is currently considered as a contraindication toorthotopic cardiac transplantation. Patients with markedpulmonary hypertension (PVR .640 dyne s/cm 5 or 8Wood units) should be considered for heart and lung transplantationand more recently long term left ventricularassistance followed with transplantation. To date, therehave been no reports in the literature of a thresholdbeyond which donor right ventricular heart failure couldoccur which would constitute a clear contraindication toheart transplantation. A normal preoperative PVR doesprovide some potential protection from acute increase inPVR causing right ventricular failure after hearttransplantation.Organ preservation and CPB may have deleteriouseffects on ventricular function. Indeed CPB has beenRVLVLADFigure 20.5 A 50-year-old man died from acute rejection aftercardiac transplantation. The autopsy showed an hypertrophied leftventricle (LV) and a dilated right ventricle (RV) (LAD, leftanterior descending). (Courtesy of Dr. Tack Ki Leung.)shown to cause an increase in PVR (5). Management ofright ventricular failure after heart transplantation andthe role for inhaled nitric oxide (NO) treatment has beenrecently reviewed (6).Pericardial effusions are commonly observed in 85% ofpatients after cardiac transplantation (7). The loss of lymphaticdrainage and the discrepancy in size between thenew donor heart and the large remaining pericardialcavity are plausible explanations (8). Even if the pericardialeffusions are common, rarely do they precipitatehemodynamic instability such as cardiac tamponade.While large but slowly accumulating pericardial effusionsusually cause little hemodynamic impairment a loculatedhematoma developing at a critical location may converselycause acute cardiac tamponade (see Chapter 11). Thus, therelationship between the size of the effusion and the clinicaloutcome is likely to show a poor correlation (8). Mosteffusions are nearly, or completely, resolved by 30 daysafter surgery (7).Transesophageal echocardiography is also useful toevaluate surgical anastomosis in the posttransplantationperiod (Fig. 20.6). The main pulmonary artery anastomosisappears as a suture ridge within the vessels. Stenosisshould be ruled out by two-dimensional (2D) color flowimaging to detect turbulent flow and by continuous-wave(CW) Doppler to measure the systolic gradient acrossthe anastomosis. The pulmonary artery catheter can alsobe used to document any gradient across the RV and thepulmonary artery (Fig. 20.7C) (9). The mid-esophageallong-axis or two-chamber view shows an elongated LAnow composed of both donor and recipient atrial tissue(Fig. 20.8). The suture line within the left and right atriaalso appears predominantly as an echodense ridge(Fig. 20.6). Acquired cor triatriatum may develop secondaryto infolding of the redundant tissue from excessivedonor atrial tissue. Post-CPB examination should thus