Minimally invasive mitral valve replacement redo surgery under ventricular fibrillation in a patient with dextrocardia and situs inversus totalis: a case report

Abstract

Background

Dextrocardia is a rare cardiac malposition where the heart’s normal orientation is reversed and is most commonly associated with situs inversus totalis (SIT). Such cases are technically challenging when heart surgery is needed, especially re-do surgery.

Case presentation

A 72-year-old female patient was referred to our hospital with complaints of chest tightness and reduced activity tolerance. The patient had a history of mitral valve replacement (MVR) with a bioprosthesis ten years prior. Chest X-ray showed dextrocardia with SIT in the patient. Structural valve degeneration of the mitral bioprosthesis and moderate tricuspid regurgitation were observed by transthoracic echocardiography. The patient underwent a successful re-do mitral valve replacement under ventricular fibrillation (VF) via a left anterolateral mini-thoracotomy. The recovery of the patient was uneventful.

Conclusions

Redo MVR under VF without aortic cross-clamping through a mini-thoracotomy can be safely and effectively carried out in patients with SIT.

Background

Mirror image dextrocardia is a rare congenital condition characterized by the reversal of the heart’s normal orientation within the chest cavity. Like in levocardia, atrial situs can be variable in dextrocardia which is either solitus, inversus, or ambiguous; out of these, dextrocardia with situs inversus totalis (SIT) is the most common variant. This case study presents the successful management of a 72-year-old female patient with dextrocardia and SIT who underwent a redo mitral valve replacement (MVR) surgery due to structural failure of a previously implanted biological mitral prosthesis under ventricular fibrillation (VF). The surgery was performed using minimally invasive techniques, posing significant challenges due to the patient’s complex anatomical variation.

Case presentation

Patient history

The patient had a history of a successful MVR surgery via sternotomy with a bioprosthesis implanted ten years prior, with regular follow-ups indicating no irregular findings. However, she presented to our hospital with complaints of chest tightness and reduced activity tolerance and requested surgical treatment. Coronary angiography revealed mild stenosis of the circumflex artery. Echocardiography showed structural valve degeneration of the mitral bioprosthesis, with an effective orifice area of 1.6cm², and a peak velocity of 3.2 m/s and an elevated mean pressure gradient of 18 mmHg. Echocardiography also showed moderate tricuspid regurgitation, mild aortic regurgitation, left atrial enlargement with an ejection fraction of 55%. Additionally, X-ray (Fig. 1A) and CT scan (Fig. 1B) image of the patient exhibited SIT and dextrocardia, further complicating surgical intervention.

Fig. 1

Pre-operative chest X-ray (A) and CT scan (B) images showed dextrocardia with SIT

Surgical procedure

A pioneering approach was adopted to perform minimally invasive mitral valve replacement redo surgery through a left thoracotomy under VF in the patient with mirror image dextrocardia. The procedure commenced with meticulous preoperative planning, including detailed imaging studies to ascertain the patient’s unique cardiac anatomy. Intraoperative positioning was crucial, with the patient placed in a modified lateral decubitus position to accommodate the mirror image orientation of the heart.

• 1. Patient Positioning and Incision: A double-lumen endotracheal tube was used for intubation and transesophageal echocardiography (TEE) was placed for cardiac monitoring. The patient was positioned with the left side elevated approximately 30 degrees. A left mini-thoracotomy was performed with a 6-centimeter-long incision at the 4th anterolateral intercostal space under right lung ventilation. The endoscopic port was placed at the left 3rd anterior intercostal space and used as a CO2 port so that the CO2 was continuously insufflated into the chest throughout the procedure to displace intracardiac air which reduces the time spent de-airing.

• 2. Pericardial Adhesion Separation: Dense pericardial adhesions in the left thoracic cavity, mediastinum, and pericardium were carefully separated to expose the heart and facilitate further surgical manipulation. In consideration of the severe adhesions, dangerous dissection around the aorta was avoided, and a strategy of myocardial protection using VF with systemic hypothermia was made.

• 3. Establishment of Cardiopulmonary Bypass (CPB): The heart-lung machine was set-up via left femoral cannulation, with a Fr17 femoral artery cannulation and a Fr23 femoral vein cannulation. Aortic root venting was not performed to avoid the risk of dangerous dissection around the root of aorta. Systemic hypothermia was achieved by cooling to below 25 °C and continuous ventricular fibrillation was induced.

• 4. Atriotomy and Valve Excision: An atriotomy was made to decompress the heart and provide access to the failed biological prosthesis. The valve was excised meticulously, ensuring minimal damage to the surrounding structures.

• 5. Valve Replacement and Repair: Following excision, MVR was performed in standard fashion using instruments for minimally invasive mitral surgery. A 25# BalMedic bovine pericardial bioprosthetic valve (Beijing Balance Medical Tech Co., Ltd., Beijing, China) was meticulously sutured into place using 2 − 0 pledgeted sutures. Knots were tied securely to ensure valve fixation and optimal functionality (Fig. 2).

Fig. 2

Follow-up echocardiography at 6 months showed well-functioned mitral bioprosthesis (A) with mild tricuspid regurgitation (B)

• 6. De-airing, Tricuspid Repair and Closure of Atrial Incisions: Before closure of atriotomy, a cannula (the left ventricle vent) was positioned across the opening of the mitral bioprosthesis via the atriotomy incision to perfuse blood to minimize air entrapment and to provide left ventricle decompression after cardioversion. The lungs are intermittently ventilated to express air from the pulmonary veins and then the atriotomy was closed with continuous 3 − 0 prolene sutures in two layers to restore the integrity of the left atrium. Upon completion of the procedure, the patient was placed in the Trendelenburg position and de-airing ascertained under TEE guidance. When rewarming was completed, cardioversion was performed, and the heart recovered to sinus rhythm. Subsequently, a right atrial transverse incision was made, and the tricuspid annulus was reshaped using the Kay technique with a pledgeted mattress suture. The right atriotomy was closed with continuous 5 − 0 prolene sutures in two layers.

• 7. Hemostasis and Closure: After confirming the satisfactory performance of the newly implanted valve by TEE, the patient was weaned from cardiopulmonary bypass. The femoral venous and artery cannula were removed, and the femoral artery and vein were sutured. Meticulous hemostasis was then performed. The chest incision was closed layer by layer, and a pleural chest drainage tube was placed on the left side through a separate intercostal puncture. Altogether, the cardiopulmonary bypass time was 200 min, operating time was 289 min, ventricular fibrillation time was 95 min, and no blood transfusion was needed.

Postoperative management and patient outcome

Following the surgical procedure, the patient was transferred to the surgical intensive care unit for close monitoring and postoperative management. The recovery of the patient was uneventful with no perioperative complications registered. The patient was discharged on postoperative day 7. Follow-up echocardiography at 6 months showed well-functioned mitral bioprosthesis (Fig. 2A) with mild tricuspid regurgitation (Fig. 2B).

Discussion and conclusions

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 perfused VF with systemic hypothermia, hence, avoiding the risk of dangerous dissection around the ascending aorta and the pulmonary artery trunk to make space for Chitwood clamp. VF with moderate hypothermia has been proved safe in redo mitral valve surgeries either via sternotomy of right thoracotomy, without necessarily compromising myocardial protection [7, 8]. 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. The original valve sewing ring should be removed with caution because it is frequently “socked in,” and when removal of the old sewing ring will result in severe annular disruption, the ring may be left in place and used as a “neoannulus” for suturing. Extra attention should be paid to avoid injury of the circumflex coronary artery which runs near the lateral scallop of the posterior leaflet in such cases, and bites must not be overly aggressive in depth when inserting stitches. Whereas on the other hand, the tricuspid valve does have an asymmetric three-dimensional figure. Annuloplasty with rigid ring or flexible band has been showed with superior long-term outcome. However, a turned-over rigid three-dimensional ring, such as a Medtronic Contour 3D ring, Edwards Physio Tricuspid or MC3 ring, would not have fit in such patients. Due to financial reasons of some poor patients in China, we sometimes perform Kay’s tricuspid repair in our center and have achieved satisfying outcomes. In this case, a Kay procedure was chosen for annuloplasty. And one-year follow-up echocardiography showed mild tricuspid regurgitation (Fig. 2B).

Caused by the previous surgery via sternotomy, there was dense adhesions of the sternum, mediastinum and the heart, hence the left atrial appendage was considerably fixed in position with poor compliance. Therefore, the left atrial appendage was not managed for fear that an aggressive closure might increase tension leading to unexpected rupture of the left atrial appendage.

Also, in this case, a traditional left atriotomy was selected instead of superior transseptal (STS) incision for two reasons. First, it is reported that the STS incision is associated with higher incidence of new pacemaker and new junctional rhythm [9]. Since a redo procedure is already a risk for postoperative arrhythmia, STS incision was not selected. Also, a traditional left atriotomy incision was selected because a cannula (the left ventricle vent) could be positioned across the opening of the mitral bioprosthesis via the atriotomy incision to perfuse blood to the left heart chambers to minimize air entrapment and to provide left ventricle decompression after cardioversion.

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.