Intra-atrial Tunnel Research Articles

Cavopulmonary anastomosis in staging toward fontan operation: pathologic substrates

Background. A review of the history and practice of cavopulmonary connections in staging toward Fontan operation and the pathologic experience at Padua University is presented. Methods. Gross and histologic assessment of the heart-lung blocks removed at autopsy in the cases in which the cause of death could be related to a dysfunction of the cavopulmonary anastomosis were performed. Results. The main complications were distortion of the intraatrial tunnel and thrombosis of the pulmonary branches of the cavopulmonary anastomosis. Conclusions. The cavopulmonary anastomosis remains a widespread procedure, both as a preliminary step to a Fontan operation and as an integral part of a Fontan or modified Fontan procedure in all those cardiac malformations characterized by a hypoplastic right or left ventricle in which these ventricles are too small to support the whole circulation.

Some techniques for the correction of the congenital heart disease with autologous flap

14 living flaps in 8 children were used to repair for the congenital heart disease, because artificial material and xeno grafts were shrunk in growing children but living flaps were going to glow with children. It were possible to use the living flaps to reconstruct of pulmonary outflow in truncus arteriosus, for septoplasty in partial anomarous of pulmonary venous return and reconstruction of unloofed coronary sinus in endocardial defect with triatriatum and intraatrial tunnel in TCPC or Fontan type operation.

Cavo-pulmonary anastomosis excluding the portal venous return: an alternative for patients with protein-losing enteropathy secondary to the Fontan procedure

AbstractSevere protein losing enteropathy occurred in 3 of our 128 patients undergoing the Fontan procedure in the period of 1982 to 1994. The complication occurred 4, 4.5 and 5 years after the procedure, respectively. One patient had double inlet left ventricle while the other two had tricuspid atresia. All had initially undergone an atrio-pulmonary connection, and the duration of the enteropathy was 12, 13,5 and 15 months. All patients were in functional class IV of the New York Heart Association. The presence of protein losing enteropathy was confirmed by determining levels of fecal alfa-1 antitrypsin, enteric clearance of 51 Cromo labeled albumin, and endoscopy with histopathological study of the small bowel.They underwent further surgery to convert the atrio-pulmonary to a cavo-pulmonary anastomosis which excluded all the hepatic veins. A bovine pericardial baffle was sutured in the inferior caval vein so as to leave the hepatic venous flow draining to the right atrium and thence through an atrial septal defect to the left atrium and systemic circulation. The inferior caval venous flow was directed through an intra-atrial tunnel to the right pulmonary artery, and the superior caval vein was anastomosed to the superior aspect of the right pulmonary artery, thus completing the total cavo-pulmonary anastomosis with exclusion of the portal venous flow.Postoperatively, there was total regression of the clinical and laboratory findings. All patients are now in functional class I or II of the New York Heart Association. They have mild to moderate cyanosis up to three and a half years from the reoperation. We recommend the technique as an alternative for patients with severe protein losing enteropathy occurring after the Fontan procedure.

Total cavopulmonary connection without the use of prosthetic material: Technical considerations and hemodynamic consequences

Total cavopulmonary connection with use of an autogenous intraatrial tunnel to create a straight tube between the inferior vena cava and the pulmonary artery was attempted in several types of cardiac anomaly in eight consecutive candidates for the Fontan operation. A small right atrium with an extraordinary location of the inferior vena cava and a short superior vena cava prevented the use of this procedure in two cases. By preserving the crista terminalis and the sinus node and its arteries we prevented the development of postoperative atrial arrhythmias in the short follow-up period, and the P trigger-signal averaged P waves were not different from those of other cardiac anomalies. The proximal stump of the superior vena cava was not incised in any case to enlarge the anastomosis, even when size mismatch between the superior and inferior venae cavae existed, as in a case of bilateral superior venae cavae. Stretching the vessels by approximately 150% was possible and permitted an adequate anastomosis. Cavopulmonary connections via the intraatrial tunnel ensured smooth, nonturbulent, somewhat pulsatile flow without a pressure gradient. We concluded that the creation of an autogenous intraatrial tunnel was possible in many cases without serious complications and that this procedure has potential benefit for the pulmonary circulation in the aspect of pulsatility. (J T HORAC C ARDIOVASC S URG 1995;110: 625-32)

702–5 Improved Survival After Fontan Operation for 62 Heterotaxy Patients

The modified Fontan operation (MF) is the preferred palliative procedure for heterotaxy pts (HP) with complex cyanotic heart disease. Early mortality (EM) after MF has been reported to be greater for HP In our recent experience (1987 – 92) EM after MF has improved dramatically. In order to determine if these improved results applied to HP, we reviewed all HP who had a MF atour institution between 1973 – 92 (n = 111). From 1973–92, 111/839 (13%) pts having a MF were HP 154 (6.5%1 polysplenia, 57 (6.8%) asplenia]. HP were significantly older than non-HP at the time of MF (median age = 11 yrs vs 9 yrs; p < 0.05). We compared EM after MF for HP in two time periods: early 11973–86 In = 49)] and recent [1987–92 (n = 62)]. EM decreased significantly in the recent group [9/62 (14.5%)] compared to the early group 121/49 (43%); p < 0.001]. In our early experience, asplenia pts had increased EM compared to polysplenia pts (65% vs 23%) but, recent experience shows that EM is similar for these two subsets of HP [asplenia: 5/34 (15%) vs polysplenia: 4/28 (14%)]. Many factors, including use of an intra-atrial tunnel, have contributed to these improved results. Despite the recent reduction in EM for HP. this group remains at higher risk after MF than pts with tricuspid atresia (EM = 4%) or double inlet left ventricle (EM = 4%). This is most likely due to increased frequency of complicating features present in HP compared to non-HP For example, atrioventricular valve (AW) repair/replacement, a recognized risk factor for EM, was more frequent in HP than non-HP [28/62 (45%) vs 40/277 (14%); P < 0.001]. In HP who did not have AW procedures EM was 9% (3/34) compared to 21% (6/28) in HP who had AVV procedures. The 9% EM rate observed in HP without AW procedures is not significantly different from the 4% EM rate observed in non-HP (p = 0.2). Survival after MF for HP has improved dramatically. Although HP still experience a greater overall operative risk, some subgroups had EM rates which were not significantly different from non-HP.

Persistent Left Superior Vena Cava Draining into the Left Atrium

An 8-year-old male presented with persistent left superior vena cava draining into the left atrium, hemizygous continuation, double outlet right ventricle, cor triatriatum, and visceroatrial discordance. After correction of the double outlet right ventricle and cor triatriatum at the age of 5, he developed mild cyanosis due to a persistent left superior vena cava draining into the left atrium. At the age of 8, an intraatrial tunnel was successfully constructed with bovine pericardium to reroute the abnormal systemic venous flow.

Total cavopulmonary anastomosis: selection criteria related to postoperative results.

In this study we review our experience with total cavopulmonary anastomosis (modified Fontan procedure) which was performed in 31 patients. One patient died from postoperative cardiac low-output syndrome, the other died from a neurological complication (early mortality 6.5%). During a mean follow-up period of 15 months there was no late mortality. Preoperative assessment showed that one, two, or three of the Choussat criteria (defining the ideal Fontan candidate) were not fulfilled by 39%, 16% and 6% of our patients. In the 2 patients who died 2 and 3 of those criteria were not fulfilled. Poor outcome could not be predicted based on assessment of the pulmonary artery size (expressed as the McGoon-ratio or the Nakata-index) alone. In order to assess the relationship of pulmonary artery size and pulmonary arteriolar resistance (PVR) as a predictor of outcome, we introduced two new indices (McGoon-ratio/PVR and Nakata-index/PVR). The patient who died from poor postoperative hemodynamics had the lowest values of all patients. Among the 29 survivors we did not observe significant acquired postoperative arrhythmias. In our experience the total cavopulmonary anastomosis can be performed with a low mortality and good postoperative results. Patients who do not fulfill at least 8 of the Choussat criteria and children with a low ratio of pulmonary artery size to PVR are high-risk patients. In these children we recommend either a bidirectional Glenn anastomosis as a first-step procedure or a total cavopulmonary anastomosis with a fenestration of the intraatrial tunnel.

Prevalence of reoperation for pathway obstruction after Fontan operation

Among 334 patients undergoing the Fontan operation at two institutions and followed for a long time, freedom from reoperation for Fontan pathway obstruction was 99% at 1 year after operation and 96%, 86%, and 59%, respectively, at 5, 10, and 15 years after operation. The hazard function for reoperation had an initial very rapidly declining phase and a second phase that was still rising 15 years after operation. Twelve (17%; confidence limits [CL], 13% to 23%) of 69 patients with a right atrial to right ventricular conduit (valved or nonvalved) connection underwent reoperation for pathway obstruction, whereas only 2 (4%; CL, 1% to 10%) of 45 patients with a direct connection to the right ventricle required reoperation. Five (8%; CL, 4% to 13%) of 65 patients with a right atrial to pulmonary artery conduit connection required reoperation for pathway obstruction, and only 2 (1.3%; CL, 0.4% to 3%) of 155 patients with a direct right atrial to pulmonary artery connection required reoperation. These findings have implications as to the optimal technique of the Fontan operation and also as to use of an intraatrial tunnel as part of the repair.

Total cavopulmonary connection: A logical alternative to atriopulmonary connection for complex Fontan operations: Experimental studies and early clinical experience

To understand better the contribution of a right atrium in a valveless atriopulmonary connection, we performed some basic hydrodynamic studies. Pulsation of a valveless chamber in a simple continuous flow circuit was found to generate turbulence and thereby to increase resistance to net forward flow. Visualization of flow through cavities and around corners and measurements of energy losses across nonpulsatile cavities, corners, and stenoses indicated the importance of streamlining. These studies suggested ways in which hydrodynamic designs of the Fontan circulation might be improved. In parallel with these in vitro studies, we have developed a modified approach to Fontan reconstruction that entails exclusion of most or all of the right atrium (total cavopulmonary connection). The operation consists of three parts: (1) end-to-side anastomosis of the superior vena cava to the undivided right pulmonary artery; (2) construction of a composite intraatrial tunnel with the use of the posterior wall of the right atrium; and (3) use of a prosthetic patch to channel the inferior vena cava to the enlarged orifice of the transected superior vena cava that is anastomosed to the main pulmonary artery. The operation was performed in 20 patients between March 1987 and March 1988. The diagnoses were double-inlet ventricle (11 patients), hypoplastic systemic or pulmonary ventricle (seven patients), and absent right atrioventricular connection (two patients). There were two early deaths and one late death. None of the deaths was related to the actual procedure but rather to increased pulmonary vascular resistance (two patients) or systemic ventricular failure (one patient). Total cavopulmonary connections have the following advantages: (1) They are technically simple and reproducible in any atrioventricular arrangement and are away from the atrioventricular node; (2) most of the right atrial chamber remains at low pressure, which reduces the risk of early or late arrhythmias; (3) reduction of turbulence prevents energy losses and should minimize the risk of atrial thrombosis; (4) postoperative cardiac catheterization performed in 10 patients confirmed these favorable flow patterns with minimal gradients throughout the connections. These encouraging early results support the continuing use of total cavopulmonary connection, at least for patients with a nonhypertrophied right atrium.

Secondary Flows In The Total CavopulmonaryConnection

Total cavopulmonary connection (TCPC) is an operation commonly performed to repair some complex congenital heart defects. It consists in connecting the superior vena cava to the right pulmonary artery and in constructing a composite intraatrial tunnel connecting the inferior vena cava to the right pulmonary artery, as well. In order to clarify the local fluid dynamics in the newly created circuit, a 3-D computational model of the TCPC has been developed, using the Finite Element Method. In particular, different TCPC configurations have been studied which correspond to differently located caval anastomoses. Different patterns for secondary flows in the two outlet (pulmonary) branches have been detected, depending on the geometry of the caval anastomoses. In this paper they are discussed with reference to flow distribution into the outlet branches.