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Minimally invasive type A aortic dissection repair: aortic valve resuspension with neomedia creation and the Ascyrus Medical Dissection Stent
Type A aortic dissection is a life-threatening condition that requires immediate surgical intervention. The goal of traditional approaches is to treat the disease promptly, regardless of invasiveness, in order to achieve the quickest surgical outcome. This strategy has been shown to be associated with significant morbidity, extended recovery and postoperative complications. A minimally invasive technique, in particular a mini-sternotomy, even in cases of type A aortic dissection, can be a viable alternative, reducing surgical trauma and postoperative complications. Despite technical challenges, minimally invasive techniques offer benefits, especially for older patients. Beyond the surgical approach, new technologies and devices (like the Ascyrus Medical Dissection Stent) have also emerged, designed to streamline the surgical process while also ensuring effective results. This case highlights the feasibility and safety of minimally invasive techniques in type A aortic dissection in elderly patients, emphasizing the potential of a more conservative yet effective surgical approach.
During the last two decades, significant advancements have been made in surgical treatments to address type A aortic dissection (TAAD) by ascending aorta and arch repair [1]. Less aggressive surgical strategies have been attempted in several ways; however, a real minimally invasive cardiac surgery (MICS) approach to treat TAAD has rarely been described [2].
MICS, in particular a mini-sternotomy (MS), has shown superior outcomes, above all in terms of respiratory complications, compared to other surgical approaches in thoracic aortic surgery [3, 4]. Considering that the outcomes of TAAD repair, particularly in the elderly population, are heavily influenced by perioperative complications, an MS could be an effective strategy for this specific group of patients [5].
An MS has undoubtedly many advantages; however, it poses significant technical challenges, especially in the case of TAAD. In this scenario, devices like the Ascyrus Medical Dissection Stent (AMDS) can facilitate hemi-arch repair. The AMDS is characterized by fast and easy deployment and has been proven to reduce distal anastomotic new entry tears and to induce positive aortic arch remodelling [6–8]. These results suggest that the AMDS is a safe and effective adjunct to current surgical approaches for TAAD. Our team firmly believes in minimizing the invasiveness of a TAAD operation as much as possible while ensuring effective and durable results.
The MICS TAAD repair has been successfully performed at our centre on 10 patients [30% female, mean age 70.3 years old, 95% confidence interval (CI) 67.9–72.6]. All patients arrived in our emergency department or were referred from spoke hospitals with Stanford type A dissection with stable haemodynamic conditions. The patients selected for this approach did not show signs of coronary malperfusion. Contrast-enhanced computed tomography (CT) angiography (CTA) scans have been carefully reviewed to exclude involvement of the coronary ostia in the dissection process. All patients received transoesophageal echocardiography examinations before the skin incision to exclude associated mitral and tricuspid dysfunction. All patients had an MS either at the third or at the fourth intercostal space, depending on the patient’s anatomy. The same cannulation strategy (right axillary artery and right femoral vein) and selective cerebral perfusion modality have been used for all the patients. The average minimum temperature during the circulatory arrest was 27.2°C. Aortic valve resuspension was done for eight patients, whereas two patients needed an aortic valve replacement. Neo-media creation with Teflon was done for all. The AMDS was used in four out of 10 patients; the others received standard hemi-arch replacement.
1 - Case presentation and preoperative CT scan (0:13)
A 76-year-old woman was referred to our department with diagnosis of TAAD. The patient arrived in stable haemodynamic conditions with no signs of pericardial tamponade, neither coronary nor systemic malperfusion. The preoperative CTA scans revealed no coronary ostia involvement and no intimal tear inside the aortic arch. The epiaortic vessels were free from the dissection process, originating from the true lumen. The decision was made to proceed with a minimally invasive approach.
2 - Minimally invasive cannulation set-up for TAAD (0:51)
A minimally invasive cannulation set-up is paramount to achieve a safe procedure. A 4-cm incision is made under the right clavicle. The subclavian vein is surrounded by a vessel loop and gently pulled downward. The subclavian artery is exposed, and pulsatility is checked. The arteriotomy is performed using a #15 blade scalpel, and attention is paid to avoid injury to the posterior wall. An 8-mm Dacron graft prosthesis is sutured end to side to the subclavian artery. Haemostasis is checked, and a thin layer of biological glue is applied to ensure adequate sealing. Femoral venous cannulation is achieved by the percutaneous transoesophageal-guided technique. The vacuum can be applied to ensure adequate blood venous drainage.
3 - MS set-up and epiaortic vessel exposure (1:52)
A midline 6- to 7-cm incision is made 2 cm below the jugular notch. Subcutaneous tissues are mobilized. The third intercostal space is palpated and mobilized. After lung deflation, the intercostal space is entered with Kelly forceps. Great care is needed to avoid injury to the internal thoracic vessel bundle. An MS is performed either in a “J” or “inverted L” shape, as in this case. The pericardium is opened with a small hole in the case of tamponade to avoid rapid haemodynamic decompensation. Then, the pericardium is largely opened. Silk stay sutures are applied on the edge of the pericardium and then secured to the skin to ensure adequate space in the surgical field. The retractor is removed and re-applied, holding to the stay sutures, to provide excellent visualization of the surgical field. The heparin dosage is completed, the lines are connected and cardiopulmonary bypass is started. A carbon dioxide inflow line is tunneled as shown. The innominate vein is surrounded and gently pulled upward. A left ventricular vent is passed through the right superior pulmonary vein. The aorta and the pulmonary artery are mobilized. Epiaortic vessels are carefully dissected. The brachiocephalic trunk and the common carotid artery are surrounded by cotton tape.
4 - Aortic valve resuspension and neomedia creation (5:12)
The core temperature is cooled to 28°C, the aorta is cross-clamped and the left ventricular vent is activated. The false lumen is entered. The true lumen is opened, and the aortotomy is extended. After a rapid check, a large intimal tear is noted just above the non-coronary sinus. The coronary ostia are assessed and noted free from the dissection process. Del Nido cold blood cardioplegia is administered directly into the ostia. After careful inspection, the aortic valve appears to be not involved in the disease, and the root is deemed repairable. Resuspension of the aortic valve with neomedia is the procedure of choice due to its efficacy and good long-term results [9, 10].
The ascending aorta is cut down to the intimal tear. The aorta is further resected and trimmed up to 4 to 5 mm above the aortic valve commissures. The commissures of the aortic valve are resuspended with the usual technique. A subcommissural repair is also performed. The neosinotubular junction is then reinforced with Prolene continuous over-and-over sutures [11].
A large Teflon felt strip is cut to size for the non-coronary sinus. The Teflon piece is placed between the intimal and the adventitial layers to form a neomedia. Biological glue is applied in the residual space. The layers are pinched between the thumb and index fingers to enhance the effect of the glue.
5 - Circulatory arrest and AMDS deployment (9:05)
After the root and the aortic valve have been addressed, the pump flow is reduced and the brachiocephalic trunk is clamped. The aortic clamp is removed, and a soft pump sucker is inserted inside the descending aorta. The selective antegrade cerebral perfusion cannula is inserted into the left common carotid artery under direct vision. The brain oxygen saturation levels are monitored during the entire procedure. The aortic arch is carefully inspected. In the absence of any visible intimal tears, the AMDS is used to stabilize the true lumen within the arch and the first part of the descending aorta [12].
The device has been sized previously based on the CT angiogram parameters. The stent is gently advanced inside the true lumen. When the correct position is reached, the protective sheath is removed. The green cap is pulled until the wire is fully out. The blue holder is then retracted.
The 4-0 polypropylene suture is passed through the polytetrafluoroethylene sewing cuff of the AMDS and the aorta, then through the Teflon felt strip and the Dacron straight graft tube.
When the anastomosis is almost finished, the cannula inside the left common carotid artery is removed. The anastomosis is completed, and the graft is de-aired. The pump is stopped for a few seconds. The clamp is removed from the brachiocephalic trunk and reapplied to the graft. The pump flow is then restored.
The Dacron graft is shortened and beveled to size the proximal anastomosis. The aortic root vent is placed on the Dacron tube. The proximal anastomosis is carried out with the standard technique. De-airing manoeuvres are performed, and the cross-clamp is released.
6 - Postoperative CT scan and follow-up results (13:09)
The patient was extubated 16 hours postoperatively, and the in-hospital stay was uneventful. She was discharged to cardiology rehabilitation on postoperative day 9. The predischarge CTA scans showed no residual dissection of the root and ascending aorta and the correct position of the AMDS. The aortic regurgitation was trivial at discharge. The patient is alive and conducting a normal life after nine months.
The 30 day-mortality in this group of patients was 0%. One patient out of 10 was re-explored for mediastinal bleeding. The mean endotracheal intubation time was 46.6 hours (95% CI 30.2–62.9) and the average hospital length of stay was 8.1 days (95% CI 5.7–10.9). All the patients were discharged to a cardiac rehabilitation centre.
Our experience with MICS thoracic aortic surgery showed improved respiratory outcomes compared to the standard approach [4]. This result led us to push the boundaries of MICS not only in elective surgery but also in the emergency setting of TAAD repair, the goal being to decrease the intubation time and length of in-hospital stay.
Nowadays, surgeons can rely on multiple strategies, tools and devices to accomplish safe and less invasive TAAD repair. The AMDS can be a game-changer in this scenario due to its fast deployment and the reduction of new entry tears in the distal anastomosis. The AMDS should not be applied universally to all patients; instead, its use should be carefully restricted to specific anatomical conditions. These include patients in whom intimal tears are located within the aortic arch, in whom dissection extensively involves the supra-aortic vessels or in the presence of large aortic aneurysms. Such scenarios may increase the risk of complications and limit the device's effectiveness [12].
We acknowledge that addressing TAAD repair by an MS can pose a considerable challenge for the surgeon and should be attempted only by experienced aortic surgeons. Although an MS can add complexity to TAAD repair, it also allows the surgeon to accomplish the entire spectrum of an aortic root repair or replacement.
Finally, this technique should be tailored to the patient’s clinical condition and should be avoided in patients with clear signs of coronary malperfusion due to the inherent difficulty of bypassing the coronaries if needed.
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Authors
Francesco Cabrucci1,2, Giulio Pellegrini2, Beatrice Bacchi2, Francesco Ferrara2, Paolo Balestracci2, Dario Petrone2, Giulia Bessi2 & Riccardo Codecasa2
Affiliations
1 Lankenau Institute for Medical Research, Main Line Health, Wynnewood, PA, USA
2 Cardiac Surgery Unit, AOU Careggi University Hospital, Florence, Italy
Corresponding Author
Francesco Cabrucci
Lankenau Institute for Medical Research
Main Line Health
Wynnewood
PA
USA
Keywords
© The Author 2024. Published by MMCTS on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
