|Year : 2013 | Volume
| Issue : 2 | Page : 68-71
Caval division technique and venous drainage after surgery for sinus venosus atrial septal defect
Kelechi E Okonta1, Vijay Agarwal2
1 Department of Surgery, Division of Cardiothoracic Surgery, University of Port-Harcourt, PMB 5323, Port-Harcourt, Nigeria
2 Department of Cardiac Surgery, Institute of Cardiovascular Diseases, Madras Medical Mission, Chennai, Tamil Nadu, India
|Date of Web Publication||13-Feb-2014|
Kelechi E Okonta
Department of Surgery, Division of Cardiothoracic Surgery, University of Port-Harcourt, PMB 5323, Port-Harcourt
Source of Support: None, Conflict of Interest: None
Bacgrounnd: The main reason for the adoption of the caval division technique is primarily to avoid sinus node dysfunction post-operatively. Equally, this technique also has the advantage of reduced complication of venous obstruction either across the superior vena cava right atrial (SVC-RA) appendage junction and/or pulmonary veins area.
Objectives: To assess the impact of Caval Division Technique on venous drainage after surgery.
Methods: The medical records for 38 consecutive patients who had a sinus venous atrial septal defect repair using the caval division technique from September 2009 to October 2011 were retrospectively reviewed and grouped into two: A total of 33 patients with normal intraoperative pressure across the anastomotic and venous areas (Group 1) and 5 patients with increased intraoperative venous pressure gradient across these areas (Group 2) with 1 patient in Group 2 having immediate surgical intervention.
Results: The pressure across the cavoatrial anastomotic sites in 2 patients was 8 mmHg, in 2 patients was 6 mmHg and in 1 patient was 11 mmHg as indicated by the intraoperative pressure monitoring line and/or transesophageal echocardiograpy. However, the echocardiography performed at follow up showed no gradient across the SVC-RA appendage anastomotic site and there was no mortality recorded.
Conclusion: In conclusion, the early operative impact of the caval division technique on venous drainage is of a good outcome and even when detected by intraoperative pressure line monitoring or transesophageal echocardiography, it can resolved spontaneous or attended to by additional band resections, especially in young children.
Keywords: Caval division technique, pulmonary venous obstruction, superior vena cava obstruction
|How to cite this article:|
Okonta KE, Agarwal V. Caval division technique and venous drainage after surgery for sinus venosus atrial septal defect. Nig J Cardiol 2013;10:68-71
| Introduction|| |
While the impact of the caval division technique on the sinus rhythm has been extensive written in the literature, on the contrary there is a paucity of literature on the effect of the adoption of this technique on the venous drainage. ,,
The main reason for adopting the caval division technique is primarily to avoid sinus node dysfunction post-operatively. ,, There has also been the observation that the complication of venous obstruction involving the superior vena cava (SVC) and/or pulmonary vein, was less with this method, especially when employing adequate cavoatrial drainage and pericardial or prosthetic patch placement. ,, It was also observed that double-patch technique was attended by less complication of the venous obstruction as this technique allows for the enlargement of the cavoatrial junction. 
The aim of the study was to review the impact of the technique on venous drainage following surgery for sinus venosus atrial septal defect with the partial anomalous pulmonary venous connection (PAPVC).
The basic surgical guides to ensuring adequate drainage are thus: After performing median sternotomy and initiating cardiopulmonary bypass following the cannulation of the aorta, left innominate and inferior vena cava and the patient cooled with the heart arrested using cold blood antegrade cardioplegia, the azygos vein was doubly ligated and transected to increase visibility; the SVC was transected above the opening of PAPVC with the distal stump over sewn above the anomalous pulmonary vein while avoiding stenosis and/or distortion of the veins. The tip of the right atrial (RA) appendage was opened and the pectinate muscles resected to provide wide opening and then anastomosed to proximal SVC using of absorbable sutures to accommodate future growth. An autologous pericardium was used to suture the margin of the sinus venosus defect, baffling the SVC orifice to direct blood flow from the anomalous pulmonary veins, through the conduit, through the sinus venosus defect into the left atrium. The atriotomy was then closed and de-airing maneuvers performed and cross-clamp released. Intraoperatively, the gradients across the anastomotic site were measured using pressure monitor line by piercing the proximal and distal points of the anastomotic site and taking their difference. To avoid the atrial tissue blocking/clogging the pressure monitoring (PM) puncturing needle, the PM line should be flushed regularly and after every piercing carried out.
| Materials and Methods|| |
The medical records of 38 consecutive patients with sinus venous atrial septal defect and who had repair using the caval division technique from September 2009 to October 2011 were retrospectively reviewed. Five out of these patients had pressure increase to ≥6 mmHg across the cavoatrial anastomotic site and the pulmonary venous area intraoperatively as detected by PM line or transesophageal echocardiography forming Group 2 while the rest 33 patients with normal pressure across these sites as Group 1. One out of the 5 patients had further surgical intervention intraoperatively by trabecula resections. The mean and standard deviations (SD) for the age, the weight; the aortic cross clamping time, the mean cardiopulmonary bypass time, the mean hospital stay and the mean intensive care unit (ICU) stay were analyzed using International Business Machine SPSS Statistics version 21 for Windows. The t-test for independent samples was applied for the grouped data with P < 0.05 taken as level of significance.
| Results|| |
The mean age for the whole patients was 14.7 years ± SD 12.8, the male to female ratio was 3:4, the mean weight was 32.9 kg ± SD 21.2; the mean cross aortic time was 60.8 min ± SD 22.9, the mean cardiopulmonary bypass time was 92.0 min ± SD 38.2; the length of hospital stay was 9.4 days ± SD 1.9; the ICU day was1.5 days ± 0.8 [Table 1].
The pressure across the cavoatrial anastomosis in 2 patient was 8 mmHg, in 2 patients was 6 mmHg in and in 1 patient was 11 mm in 1 patients as shown by the intraoperative pressure line monitoring and/or echocardiography findings [Table 2]. However, the echocardiography performed at follow-up showed no gradient across the SVC-RA appendage anastomotic site. There was no vena cava or pulmonary vein obstruction noted at follow-up and no mortality was recorded.
|Table 2: The characteristics of the patients with pressure gradient across the SVC‑RA>6 mmHg|
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| Discussion|| |
The caval division technique as reported in the literature is of a good outcome in terms of reduced sinus node dysfunction post-operatively. However, there are sparse accounts on this surgical technique on, specifically, venous obstruction. The reason for the late venous obstruction is usually as a result of the continual fibrosis at the anastomosis between the caval end and the atrial appendage.  The other notable complications following the repair of sinus venosus atrial septal defect with partial anomalous pulmonary venous congestion are sinus node dysfunction and residual intracardiac defects. ,,,,,,,
The intraoperative measuring of the pressure gradient across these anastomotic sites can be performed using the pressure monitor line or with the transesophageal echocardiography. The record of turbulence and/or a significant SVC-right atrium causing turbulence across the right superior pulmonary vein at the level of the patch will indicate evidence of venous obstruction ,, and of course, the need for intervention even before coming off bypass. The late venous obstruction on the other hand can be identified by the clinical features the patient may present with or the echocardiography findings during the follow-up. ,,
The causes of the initial turbulence or increase pressure gradient across the different venous points, as was observed in our patients were: The inertia after the establishment of the new anastomosis; lack of adequate resection of the trabecula strands (this was demonstrated in one of the patients) and the real problem result from improper surgical techniques of anastomosis.  The other causes, especially for late complications, apart from the progression of fibrosis at the cavoatrial anastomotic site, are the contraction of the pericardium or prosthetic patch with the consequent compromise of the various caliber of the orifices. , Furthermore, in some anatomical variants such as sinus venous-atrial septal defect with a high PAPVC; that is, the anomalous pulmonary vein is inserted more than 2 cm from the cavoatrial junction, the surgical repair with intra-atrial autologous pericardial patch has a high incidence of venous obstruction because of increased tendency for the patch to contract thereby resulting to symptomatic pulmonary venous obstruction. So, for this variant, the use of caval division technique was advocated as being the effective surgical options. , Other methods that could be adopted in other to avoid venous obstructions are; ensuring adequate anastomosis when using the caval division techniques, the use of the atrium as a patch option, the creation of double barrel kind of anastomosis and the use of double-patch technique or modification of the single-patch technique by the use of the transcaval approach. ,,,,
From our review, out of the 38 patients who had repair using the caval division technique 5 (13.2%) had initial turbulence across the SVC-RA appendage anastomotic point and non at the pulmonary venous side while in 33 patients the pressure was normal intraoperatively and evidently, the cardiopulmonary bypass time was less in this patients [Table 2], though not statistically significant. The pressure gradient resolved spontaneously after some waiting time intraoperatively in 4 patients without deteriorating clinical effect while 1 patient required refashioning of the anastomosis by further resection of the trabecula bands at the immediate post-operation period. Interestingly, the increased pressure gradient noted were amongst the younger age patients (Group 1) as against the older patients (Group 2); the reason may be from the small caliber vessels and organs in these patients (though not statistically significant) that could have leads to some technical challenges during anastomosis at the cavoatrial area. This was DiBardino et al. observation in 30 patients who had this procedure, with 4 of patients developing post-operative venous obstruction. The obstructions in 3 patients were systemic vein; at the cavoatrial anastomotic point and in 1 patient was pulmonary vein. The authors concluded that the venous obstruction, which was common among the younger and smaller children was as a result of their vessels, which were commensurately smaller and suggested that an argumentation patch should be performed in those cases.  And to forestall possible future obstruction in this kind of patients; absorbable sutures are considered veritable.  However, it appeared that the caval division technique was apt in solving these problems.
The atriotomy occasioned by the use of this technique allowed for the better assessment of the septal defect and tension free placement of the harvested pericardial patch. Equally, during the immediate post-operative and the follow-up periods of these patients, there was no further evidence of venous obstruction as noted from our previous review. 
| Conclusion|| |
The early operative impact of the caval division technique on venous drainage is of a good outcome and even when detected by intraoperative pressure line monitoring or transesophageal echocardiography, it can resolved spontaneous or attended to by additional band resections especially in young children.
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[Table 1], [Table 2]