The Novel Use of a Rapid Deployment Valve in Type A Aortic Dissection

Introduction

Rapid deployment valves (RDVs) are bioprosthetic valves that are relatively new to cardiac surgery. Initially designed for the aortic valve position, unlike conventional surgical prosthetic valves, circumferential sutures are not required to implant these valves into position. Given their mode of implantation, these valves have played an important role in the evolution of valve and complex cardiac surgery over the past decade. In particular, minimally invasive cardiac surgeons have greatly benefited from RDVs as these valves can be deployed through small incisions. Moreover, there is mounting evidence showing that these valves can reduce operative times,^1–4 hence facilitating complex and concomitant operations. In the TRANSFORM trial, for isolated aortic valve replacement (AVR), the mean cross-clamp and cardiopulmonary bypass (CPB) times were 49.3 ± 26.9 min and 69.2 ± 34.7 min, respectively, which are favorable compared with the Society of Thoracic Surgeons database (76.3 min for cross-clamp and 104.2 min for CPB). ⁴ The TRITON trial also showed that the use of Intuity valves (Edwards Lifesciences, Irvine, CA, USA) was associated with reduced operative times. ⁵ In addition to demonstrating the safety and feasibility of using Intuity valves, this trial also highlighted their excellent hemodynamic performance up to 1 year after implantation. ⁵ Finally, RDVs have also been safely and effectively used in the elderly and those with active infective endocarditis. ⁶ However, to date, there are no examples of RDVs being used in a patient presenting with type A aortic dissection. Herein, we report the case of a patient who presented with type A aortic dissection and underwent ascending aorta and hemiarch replacement under deep hypothermic circulatory arrest and AVR using a 19 mm Intuity RDV.

Case Report

An 82-year-old female patient presented to the emergency room with chest pain. A chest computed tomography scan revealed aortic dissection originating from the aortic root and extending to the level of the gastroesophageal junction. The dissection involved the innominate, right subclavian, and right axillary artery. The patient was taken to the operating room for AVR and ascending aorta and hemiarch replacement. Intraoperative transesophageal echocardiography confirmed acute type A aortic dissection, with a dissection flap extending from the coronary sinuses throughout the ascending aorta, aortic arch, and into the descending thoracic aorta. A fibrocalcific aortic valve with mild-moderate aortic stenosis and moderate insufficiency (AI) was also noted. The patient provided informed consent for the preparation and publication of this case.

First, the left common femoral artery was exposed. Then, 5,000 units of heparin was given and 2 multipurpose DeBakey clamps were applied to the femoral artery distally and proximally. The femoral artery was opened, and an 8 mm Dacron graft was sewn to it. The aortic limb of the CPB circuit was connected to the 8 mm Dacron graft. The arterial line was Y-ed off to facilitate antegrade cerebral perfusion.

A median sternotomy was performed, and the pericardium was opened. The innominate vein was isolated using a vessel loop. The innominate artery was then isolated with an umbilical tape. The left common carotid artery was also mobilized with a vessel loop. CPB was initiated using a two-stage venous cannula in the right atrium and the left femoral artery, and the patient was actively cooled to 18 °C. A left ventricular vent was inserted through the right superior pulmonary vein, and a retrograde catheter was inserted into the coronary sinus. While cooling, the aorta was mobilized from the pulmonary artery and surrounding tissue, a cross-clamp was applied, and cold-blood cardioplegia was administered via the retrograde catheter. The aorta was opened through a transverse incision, which was extended to the sinotubular junction (STJ). On opening the aorta, the true and false lumens were identified. There was no thrombus in the false lumen.

More cardioplegia was delivered via the left and right coronary ostia and the aortic valve was inspected. The noncoronary cusp was calcified and prolapsing. Interestingly, the dissection extended proximally only to the level above the commissures in the noncoronary sinus; the left and right coronary sinuses had not dissected. It became evident that the moderate AI, which was noted on the intraoperative echocardiogram, was secondary to the prolapsing cusp and not due to the dissection. Thus, a decision was made to replace the aortic valve. The native aortic valve was excised, and the annulus was debrided from calcium and measured to fit a 19 mm bioprosthetic valve. The dissection flap in the noncoronary sinus was repaired with injecting BioGlue into the false lumen. The aortic wall at the STJ was reinforced with Teflon polytetrafluorethylene felt using interrupted 4-0 Prolene sutures. A 19 mm Intuity RDV was subsequently implanted in routine fashion, resulting in a well-seated prosthetic valve with a transvalvular mean pressure gradient of 6 mm Hg. The surgery was completed by replacing the ascending aorta and hemiarch. The total CPB time was 198 min, cross-clamp was applied for 113 min, and deep hypothermic circulatory arrest time was 29 min. Postoperative course was complicated by acute renal failure requiring continuous renal replacement therapy and dialysis, shock liver, atrial fibrillation, and acute respiratory distress syndrome. The patient was discharged home on postoperative day 37. On 8-month follow-up, transthoracic echocardiography revealed a well-seated and normally functioning Intuity RDV (Supplemental Video).

Discussion

Acute type A aortic dissection carries a significant clinical burden on patients and care providers.^7,8 The extent of the dissection increases the complexity of the operation, which may also affect the outcome. An operation for type A aortic dissection may involve extended repair, including deep hypothermic arrest to address repairing the aortic arch. These surgeries are often long, resulting in a spectrum of complications, including ischemia-induced end-organ damage and coagulopathy. Therefore, strategies that can shorten the operation should be sought and utilized. Herein, we report the case of a patient who presented with type A aortic dissection that involved the noncoronary sinus and extended to the gastroesophageal junction. The aortic valve was trileaflet, while the noncoronary cusp was calcified and prolapsing. The mechanism of aortic regurgitation was due to leaflet pathology, so resuspending the commissures would not have been effective. Thus, in addition to replacing the ascending aorta and the hemiarch, an AVR was indicated. To expedite the operation and reduce intraoperative times, an Intuity RDV was used for the AVR to great effect.

This is a unique case that demonstrates the safety and feasibility of using an RDV in complex situations, such as a type A aortic dissection in which the mechanism of aortic valve regurgitation was due to leaflet pathology rather than dissection involving the aortic annulus. Given the current lack of clinical data, this is not a strategy that should be commonplace when addressing aortic valve/root pathology in the dissection setting. However, our case shows that an RDV may be considered for patients presenting with type A aortic dissection and aortic valve disease. Using an RDV in this case helped reduce the operative time and mitigate the surgical risk and complexity. Conventional AVR would have resulted in longer CPB and cross-clamp times. The advent of RDVs offers more options to surgeons when faced with aortic valve disease and should be included in their armamentarium even in type A aortic dissection.

Conclusions

RDVs have revolutionized different areas of cardiac surgery, including valve surgery, minimally invasive cardiac surgery, and complex and concomitant operations. Herein, we present the rare and unique case of a patient who presented with type A aortic dissection that involved the noncoronary cusp of the aortic valve. To facilitate a faster and less complex operation, an Intuity RDV was used to replace the aortic valve to great effect. This case further demonstrates the safety and feasibility of using these prostheses in unique and challenging situations.