Jan M. Quaegebeur

Severe stenotic scar contracture of the microvel hemashield right-sided extracardiac conduit

We report 2 patients who developed severe scar contracture of a Microvel Hemashield valveless right-sided extracardiac conduit implanted 14 months earlier. In both cases, the diameter of the conduit was reduced along its entire length, with the prosthetic material plicated inward by retraction and organization of connective fibrous tissue on either side of the conduit.

ASSESSMENT OF VENTRICULAR SEPTAL DEFECT CLOSURE BY INTRAOPERATIVE EPICARDIAL ULTRASOUND

Intraoperative epicardial two-dimensional echocardiographic imaging, color flow mapping and contrast echocardiography were used in 31 patients after patch closure of a ventricular septal defect to determine their respective values in the assessment of residual shunting after cardiopulmonary bypass and for the prediction of long-term results. Epicardial imaging showed no incidence of patch dehiscence. Residual shunting detected by color flow mapping or contrast echocardiography was graded into one of four categories (0 to III). Real time analysis of color flow mapping studies suggested no shunting (grade 0) in 2 patients, grade I shunting in 20, grade II in 8 and grade III in 1; contrast studies suggested grade 0 in 15, grade I in 6, grade II in 8 and grade III in 2. Interobserver variation in real time encoding of grade I or II shunting was 25% by color flow mapping and 6% by contrast echocardiography. Subsequent frame by frame analysis revealed that both diastolic and early systolic right ventricular turbulence gave rise to false positive results during real time analysis of color flow mapping studies. Color flow mapping allowed exact localization of residual shunting, whereas contrast echocardiography allowed better semiquantification. Postbypass results were correlated in 30 patients with late postoperative precordial studies (mean interval 7.5 months). Persistent shunts were found in 6 (20%) of 30 patients. No patient required reoperation for residual shunting. The predictive value of immediate grade I or II shunting as a marker for persistent long-term shunting was poor, whereas both patients with immediate grade III shunting had shunt persistence, indicating that immediate revision should be considered in such patients. Intraoperative epicardial ultrasound is valuable for the immediate exclusion of important residual shunting after ventricular septal defect closure. Maximal information is obtained when color flow mapping and contrast echocardiography are used in combination.

Determinants of survival after surgery for mitral valve regurgitation in patients with and without coronary artery disease

Mortality and its determinants were assessed in 181 consecutive patients undergoing primary mitral valve surgery for pure mitral regurgitation with coronary artery disease (MR + CAD, 79 patients) or without (MR no CAD, 102 patients). Early mortality (C10% vs. 3%) and 6-year estimate of survival (55% +/- 7.1% vs. 82% +/- 4.4%) were significantly different. Mortality was not significantly different in patients with CAD + MR of an ischemic (49 patients) or a non-ischemic etiology (30 patients). Multivariate testing using Cox regression models of overall mortality in patients with MR + CAD indicated that preoperative renal dysfunction, high right atrial pressure, ejection fraction less than 45% as well as qualitatively reduced left ventricular function and left ventricular end-diastolic volume index greater than 120 ml/m2 are associated with decreased survival. Multivariate testing in patients with MR no CAD only identified insertion of a mechanical prosthesis and a degenerative etiology of mitral valve disease as independent predictors of survival. Thus, a common denominator of preoperative pathology (renal dysfunction) and indices of right and left ventricular dysfunction determined overall survival of patients with MR + CAD. Survival of patients with MR no CAD was determined by the valve prosthesis and the etiology of valve disease.

Aortic atresia with normal left ventricle: one-stage repair in early infancy.

Successful one-stage repair of aortic atresia with a left ventricle was performed in a 6-week-old infant using a new technique. After patch enhancement of the hypoplastic aortic arch, the transected proximal pulmonary artery was directly anastomosed to the aortic arch. An intraventricular baffle established continuity between the left ventricle and neoaortic valve, and a homograft conduit was inserted between the right ventricle and pulmonary artery bifurcation.

Subaortic obstruction : intraoperative echocardiography as an adjunct to operation

Fourteen patients undergoing operation for subaortic obstruction (membranous obstruction in 11 patients, tunnel obstruction in 2 patients, obstruction due to reduplicated mitral valve tissue in 1 patient) were evaluated by intraoperative epicardial echocardiography. In all 9 patients with discrete obstruction who underwent prebypass epicardial echocardiography, the septal and lateral attachments of the lesion were correctly demonstrated. The precise extent of tunnel stenosis was seen in both patients. The lateral attachment of the membrane in 4 patients and multiple extensions in another 2 were identified by the epicardial study (having been missed on precordial echocardiography). The discrete membrane was enucleated in 10 of the 11 patients and was partially resected in 1. One tunnel obstruction was completely relieved; the other was partially relieved. Reduplicated mitral valve tissue in the remaining patient was completely resected. Epicardial imaging after bypass showed remnants of the membrane in 2 patients. Intraoperative Doppler echocardiography and color flow imaging confirmed the absence of clinically significant residual gradients (less than 20 mm Hg) in all but 1 patient with tunnel obstruction. Epicardial imaging provided excellent morphological information about obstructive lesions of the left ventricular outflow tract and enabled immediate assessment of surgical repair.

Intraoperative Echocardiography in Congenital Heart Disease: An Overview

Intraoperative epicardial cross-sectional imaging has now been available for some 8 years [1—5] without gaining widespread acceptance as an essential aid to the cardiac surgery of congenital heart disease. Despite the high-quality imaging of cardiac morphology obtained by direct epicardial scanning, the epicardial two-dimensional image alone may provide little important additional diagnostic information when compared to the preoperative findings. As the primary morphologic diagnosis is seldom incomplete in such cases after combined preoperative cardiac catheterisation and echo studies, most cardiac surgeons consider additional prebypass intraoperative ultrasound studies as an unnecessary prolongation of surgical time. In recent years, the use of intraoperative contrast echocardiography to assess the results of surgical repair has, after a period of initial surgical enthusiasm [6, 7], largely been abandoned. The reason for this was that in clinical decision making, intraoperative contrast echo proved to be an unreliable technique; it must be analysed over only the initial heartbeats following injection and the findings are dependent on a number of variables: (a) the amount of contrast medium injected, (b) the velocity with which the agent is injected, (c) the precise site of injection, and (d) the haemodynamics at that particular moment. In addition, although an intraoperative contrast study may prove the existence of a significant intracardiac shunt, it usually fails to localise its site and also fails to distinguish between one or multiple residual defects.

Role of intraoperative ultrasound examination in patients undergoing a Fontan-type procedure.

To determine its potential impact on perioperative surgical management intraoperative ultrasound examination (cross sectional imaging, colour flow mapping, pulsed and continuous wave Doppler) was used in 16 consecutive patients undergoing a Fontan-type procedure. Epicardial cross sectional imaging before bypass defined the precise intracardiac morphology in 15 of 16 patients. The preoperative morphological diagnosis was refined in four patients (25%), and this influenced surgical management in two (12%). Epicardial studies after bypass identified seven residual haemodynamic lesions in five patients (three residual intercardiac shunts, one ventricular outflow obstruction, one pulmonary artery obstruction, two mitral valve regurgitation), and led to immediate revision during a second period of bypass in three (18%). In one patient who required early reoperation residual shunting was not detected after bypass by either colour flow mapping or a contrast study. Final intraoperative studies showed a good surgical result in 14 patients (87%). Flow characteristics and flow velocities within the Fontan circulation could be assessed immediately after the patient came off cardiopulmonary bypass by means of combined pulsed wave Doppler and colour flow mapping in 14 of the 16 patients. Cross sectional studies of the left heart after bypass showed no change in ventricular function and allowed monitoring of volume replacement and ventricular filling. Intraoperative ultrasound was a valuable monitoring technique in patients undergoing a Fontan-type procedure. It refined preoperative diagnosis, monitored ventricular function, and identified or excluded residual haemodynamic lesions in most patients.