Valve surgeries have been reported to be successfully performed in patients with dextrocardia and SIT[1–2]. Minimally invasive approaches have also been shown to be accessible in such patients[3–4]. However, all redo mitral valve surgery in SIT patients reported were through re-sternotomy. To our knowledge, this is the first report of minimally invasive redo mitral and tricuspid valve surgery in a patient with SIT.
Traditional redo mitral valve surgery through median sternotomy is associated with an increased perioperative risk and has several challenges as it requires more extensive and time-consuming dissection of adhesions to the apex, aortic clamp, and myocardial protection. In the presence of dense adhesions, re-entry via sternotomy adds to an increased risk of injury to the right heart or vessel grafts in case of previous coronary artery bypass surgery. Minimally invasive mitral surgery through a mini-thoracotomy approach can usually achieve an adequate, and sometimes even better operative view of the mitral valve than re-sternotomy, without requiring dissection of adhesions. The mini-thoracotomy approach has been demonstrated to be as safe as sternotomy but with reduced length of intensive care unit stay, fewer blood transfusions, and reduced postoperative pain [5–6]. Also, in this case, a decision was made to perform the operation under VF with systemic hypothermia, hence, avoiding the risk of dangerous dissection around the ascending aorta and the pulmonary artery trunk without necessarily compromising myocardial protection. Whereas, cases combined with aortic insufficiency should be excluded as the retrograde flow may interfere with the operative field.
SIT patients could also benefit from re-do atrioventricular valve surgeries through a mini-thoracotomy. However, several special conditions should be taken into consideration for the whole surgical team when making surgical planning of such dextrocardia with SIT anatomy. For example, the selection of a suitable double-lumen endotracheal tube or bronchial blocker to ensure single right lung ventilation, rearrangement of the operation room for an opposite side surgeon position and adjustment of an opposite angle of TEE probe for monitoring.
The mitral valve has a symmetrical structure. Therefore, with adequate surgical exposure, the SIT and dextrocardia situation does not significantly add difficulty to the mitral valve procedures. Extra attention should be paid to avoid injury of the circumflex coronary artery which runs near the lateral scallop of the posterior leaflet, when inserting stitches. Whereas on the other hand, the tricuspid valve does have an asymmetric three-dimensional figure. A turned-over rigid three-dimensional ring, such as a Medtronic Contour 3D ring, Edwards Physio Tricuspid or MC3 ring, would not have fit. Thus, in this case, a Kay procedure was chosen for annuloplasty.
In conclusion, current knowledge and the success of this case suggest that redo MVR under VF without aortic cross-clamping through a mini-thoracotomy can be safely and effectively carried out in patients with SIT.