A simple technique for aortic valve replacement in patients with a patent left internal mammary artery bypass graft

Considering alternatives to transcatheter heart valves for managing patients with severe aortic valve stenosis

INTRODUCTION

Transcatheter aortic valve implantation (TAVI) is becoming the standard of care for severe symptomatic aortic stenosis (AS). Yet, some patients with AS are not indicated/eligible for TAVI. Several noninvasive, catheter-based or surgical alternatives exist, and other therapeutic options are emerging.

AREAS COVERED

This review provides an overview of non-TAVI options for severe AS. Non-invasive, transcatheter, and alternative surgical strategies are discussed, emphasizing their backgrounds, techniques, and outcomes.

EXPERT OPINION

Alternative therapies to TAVI, whether device-based or non-device-based, continue to evolve or emerge and provide either alternative treatments or a bridge to TAVI, for patients not meeting indications for, or having contraindications to TAVI.Although TAVI and SAVR are the current dominant therapies, there are still some patients that could benefit in the future from other alternatives.Data on alternative options for such patients are scarce. Many advantages and disadvantages arise when selecting a specific treatment strategy for individual patients.Head-to-head comparison studies could guide physicians toward better patient selection and procedural planning. Awareness of therapeutic options, indications, techniques, and outcomes should enable heart teams to achieve optimized patient selection. Furthermore, it can increase the use of these alternatives to optimize the management of AS among different patient populations.

Aortic root replacement in severe left ventricular dysfunction: The added value of beating-heart surgery

There are limits to the use of cardioplegic arrest during complex cardiac surgical procedures, especially in patients with severe left ventricular dysfunction. In the current report, we graphically present the detailed surgical strategy and technique for beating-heart aortic root replacement with concomitant coronary bypass grafting, for patients otherwise deemed inoperable. With support of cardiopulmonary bypass (CPB), beating-heart bypass surgery is realized, after which the bypass grafts can selectively be connected to the CPB, preserving coronary flow. Then, on the beating and perfused heart, a complex procedure such as aortic root replacement can be performed, without jeopardizing postoperative cardiac function. However, several important caveats and remarks regarding the use of beating-heart surgery should be considered, including: coronary perfusion verification and maintenance, temperature management, and prevention of air embolisms. By use of this strategy, risks associated with cardioplegic arrest are minimized, while it circumvents the potential need for long-term postoperative extracorporeal membrane oxygenation.

Ministernotomy aortic valve surgery in patients with prior patent mammary artery grafts after coronary artery bypass grafting

OBJECTIVES

Patients with patent internal thoracic artery (ITA) grafts after prior coronary artery bypass grafting surgery who require aortic valve replacement (AVR) pose unique technical challenges for safe and optimal myocardial protection. The purpose of this study is to review our short- and long-term outcomes with redo minimally invasive AVR in patients with patent in situ ITA grafts.

METHODS

From 2008 to 2016, 48 patients with at least 1 patent in situ mammary artery graft underwent minimally invasive AVR. Preoperative computed tomography was performed in all patients to evaluate the relationship of patent grafts to the sternum. Retrograde coronary sinus and pulmonary vent catheters were placed via the right internal jugular vein. The in situ ITA grafts were not clamped during AVR. Transverse aortotomy, taking care to avoid the grafts arising from the aorta, was performed to expose the aortic valve.

RESULTS

The median age of the patients was 78 years [Quartile 1 (Q1)-Quartile 3 (Q3): 71-81]. Thirty-nine (81%) patients were men, and 46 (96%) patients had aortic stenosis. The median cardiopulmonary bypass and cross-clamp times were 124 (Q1-Q3: 108-164) and 92 (Q1-Q3: 83-116) min, respectively. Moderate hypothermia at 28-30°C was used in all patients. Most patients received cold blood cardioplegia with antegrade induction and continuous retrograde delivery. Four patients received only retrograde delivery due to some degree of aortic insufficiency. Thirty-day mortality was 4% (2 of 48 patients). There was no conversion to full sternotomy, and no reoperations were performed for postoperative bleeding or sternal wound infection. Excluding the 2 patients who died in the hospital, the median postoperative length of stay was 7 days (Q1-Q3: 5-8). Overall survival at 1, 5 and 10 years was 94%, 87% and 44%, respectively.

CONCLUSIONS

Percutaneous retrograde cardioplegia combined with antegrade cardioplegia and moderate hypothermia, without interruption of ITA flow, is a safe and reliable strategy in patients with patent ITA grafts undergoing aortic valve replacement. This strategy combined with a minimally invasive approach may reduce surgical trauma, and is a safe and effective technique in these challenging patients.

Beating aortic valve replacement surgery as an alternative to transcatheter aortic valve implantation in a patient with severe aortic stenosis and left ventricular dysfunction

Background

Transcatheter aortic valve implantation (TAVI) is the standard treatment for high-risk patients with aortic stenosis (AS); however, alternative treatments for patients who are ineligible for TAVI are controversial.

Case presentation

56 year-old female who required 6 γ dobutamine support due to congestive heart failure was diagnosed as severe aortic stenosis with bicuspid valve. Echocardiography revealed left ventricular ejection fraction (LVEF) was 15%. The patient was relatively young for TAVI, and TAVI was not licensed for patient presenting with a bicuspid aortic valve in places other than the limited institutions in Japan. On pump beating aortic valve replacement (AVR) was performed with selective antegrade coronary artery blood perfusion. She resumed a completely normal lifestyle by 3 weeks after the operation.

Conclusions

A relatively young patient for TAVI who was diagnosed as aortic stenosis with severely reduced ejection fraction and bicuspid valve is reported. Beating AVR with a continuously selective antegrade-perfusion was achieved safely with good clinical results in a patient with severely reduced left ventricular (LV) function. Beating AVR can be considered as a potential alternative for patients who are ineligible for conventional surgical aortic valve replacement (SAVR) and TAVI.

Myocardial protection using del nido cardioplegia solution in adult reoperative aortic valve surgery

BACKGROUND AND AIMS

The immediate postischemic period is marked by elevated intracellular calcium levels, which can lead to irreversible myocyte injury. Del Nido cardioplegia was developed for use in the pediatric population to address the inability of immature myocardium to tolerate high levels of intracellular calcium following cardiac surgery. Our aim in this study is to determine if this solution can be used safely and effectively in an adult, reoperative population.

METHODS

All patients undergoing isolated reoperative aortic valve replacement at our institution from 2010 to 2012 were retrospectively reviewed. Demographics, comorbidities, operative variables, postoperative complications, and patient outcomes were collected. Patients were divided into two groups based on cardioplegia strategy used: whole blood cardioplegia (WB, n = 61) and del Nido cardioplegia (DN, n = 52).

RESULTS

Mean age in the study was 73.4 ± 14.3 years and 86 patients were male (76.1%). Eighty-four patients had undergone prior coronary artery bypass graft (CABG) (74.3%). Patients in the DN group required significantly lower total volume of cardioplegia (1147.6 ± 447.2 mL DN vs. 1985.4 ± 691.1 mL WB, p < 0.001) and retrograde cardioplegia dose (279.3 ± 445.1 mL DN vs. 1341.2 ± 690.8 mL WB, p < 0.001). There were no differences in cross-clamp time, bypass time, postoperative complication rate, or patient outcomes between groups.

CONCLUSIONS

Del Nido cardioplegia use in an adult, reoperative aortic valve population offers equivalent postoperative outcomes when compared with whole blood cardioplegia. In addition, use of del Nido solution requires lower total and retrograde cardioplegia volumes in order to achieve adequate myocardial protection.

Beating heart continuous coronary perfusion for valve surgery: what next for clinical trials?

Prior to the introduction of cardioplegia, beating heart continuous coronary perfusion (BHCCP) was the only available method of myocardial protection. Currently, cardiac surgery on cardiopulmonary bypass with cardioplegic arrest is the gold standard strategy. Cardioplegic arrest provides an easier and safer way to operate on a still heart. It enables the performance of a broader range of cardiac procedures, and avoids the potential difficulties of continuous perfusion on a beating heart. Despite the overall effectiveness and safety of cardioplegia, some adverse effects remain, mainly due to the insult of ischemia, which results in ischemic reperfusion injury. As a result BHCCP has seen a revival as an alternative to cardioplegia for performing complex valvular surgery. Increasing experience reporting safety and efficacy of BHCCP is being published. However, despite the reported advantages, current available evidence validating safety and efficacy of BHCCP is controversial. This article provides an overview of BHCCP highlighting the current best available evidence supporting this strategy, concerns, controversies and potential areas for further research.

Beating heart composite valve graft replacement and hemiarch aortic reconstruction in a patient with patent internal thoracic artery graft

Effective myocardial protection is often challenging in patients who have undergone prior myocardial revascularization and require reintervention on the aortic root with patent grafts. We report the case of a patient who underwent composite valve graft replacement and hemiarch aortic reconstruction after repair of a ruptured aneurysm of the right coronary sinus of valsalva combined with a right internal thoracic artery to right coronary artery bypass grafting. Because the right coronary artery ostium was obstructed by the previously placed patch, we performed the redo operation on the beating heart using continuous patent graft flow and left coronary artery ostial perfusion.

Simple Techniques to Manage the Patent Internal Mammary Artery in Redo Cardiac Surgery

The presence of a patent internal mammary artery (IMA) represents a well-known technical challenge in redo cardiac surgery. Dissection of the IMA and controlling its flow during cardioplegic delivery has thus been considered essential steps. This maneuver however, is associated with the risk of damaging the IMA. Herein, we report a technique, which involves no attempts to dissect, or clamp the IMA in 44 consecutive redo cardiac surgery procedures. The results demonstrate that this technique is simple, safe, and reduces the chance of IMA injury.

Beating-Heart Valve Surgery: A Systematic Review

Beating-heart continuous coronary perfusion (BHCCP) has been promoted as an alternative to the technique of cardioplegic arrest in valve surgery. Its potential advantage is the elimination of cardioplegia and the corollary risk of ischemic reperfusion injury. The use of CCP has been recommended especially when performing more complex operations, such as mitral valve repair, and particularly as surgeons become more familiar with beating-heart coronary surgery. We conducted a systematic review to assess the strength of the evidence supporting the efficacy of BHCCP compared to cardioplegia in valve surgery. Thirty nine reports were identified. Of these, only two were randomized control trials. Overall the studies were generally of poor quality and had a low evidence level. In those studies, mortality and major morbidity from BHCCP were within acceptable levels, nevertheless, there was no advantage over cardioplegic arrest. On the other hand there is weak evidence that it may reduce functional and biochemical markers of myocardial injury. In conclusion, BHCCP is an operative strategy in valve surgery with some potential benefits. There is, however a need for a high quality, prospective, randomized control trial to establish the exact role for BHCCP in complex valve surgery.

Aortic valve replacement with patent bilateral internal thoracic artery grafts using cross-clamp fibrillation

Aortic valve replacement in patients with patent coronary grafts poses many challenges. Intraoperative myocardial protection remains one of the key technical issues in these redo cases. We present a case of aortic valve replacement with patent bilateral internal thoracic artery grafts, using cross-clamp fibrillation.

Aortic Valve Replacement With On-Pump Beating Heart Technique

BACKGROUND

The aim of this study was to assess the efficacy and applicability of on-pump beating heart aortic valve replacement with retrograde coronary sinus (CS) warm blood perfusion.

METHODS

The prospective study included 14 consecutive patients who underwent aortic valve replacement with mechanical prosthesis using retrograde CS perfusion. The operative variables and early outcome of this procedure are presented.

RESULTS

Retrograde CS perfusion and venting the heart from the pulmonary vein provided good visualization of the operative field and performance of the operations without any difficulty. Partial oxygen pressures of CS perfusion blood and the returning blood from the coronary ostia were 288.5 +/- 34.4 and 39.6 +/- 4.6 mmHg, respectively. Postoperative peak creatine kinase-MB and troponin T values were mean 77.0 +/- 63.6 IU/L and mean 0.8 +/- 0.7 ng/mL, respectively. No mortality or major complication was observed and all the patients were discharged from the hospital in good condition.

CONCLUSIONS

On-pump beating heart aortic valve replacement with retrograde CS warm blood perfusion is a good surgical option, and has the advantage of maintaining physiologic condition of the heart throughout the procedure.

Beating heart aortic valve replacement after previous coronary artery bypass surgery with a patent internal mammary artery graft

Re-sternotomy for aortic valve replacement (AVR) in patients with a patent internal mammary artery (IMA) graft may present a challenging surgical problem. Thus, strategies to prevent IMA graft injury include avoiding its dissection and leaving the graft open. However, when aortic cross clamping and cardioplegia are required, this approach may be associated with cardioplegia washout, suboptimal myocardial protection, and anterior myocardial wall injury. We herein describe an alternative technique for AVR on the beating heart in 4 patients with patent IMA grafts. The IMA was left unclamped and continuous retrograde coronary sinus perfusion (RCSP) was administered. Additional simultaneous antegrade venous bypass graft perfusion was established according to the extent of native coronary artery disease as well as patency and level of aortic proximal anastomoses. Using additional coronary ostia backflow control, the aortic valve was successfully replaced on the beating heart in all four cases without perivalvular leak. Postoperatively, low creatine kinase-MB fraction levels and preserved or improved ventricular function suggested very good myocardial protection. No myocardial infarction occurred in any patient. In our experience, aortic valve replacement on the beating heart using simultaneous antegrade-retrograde blood perfusion is a safe and effective method in this challenging subset of patients to prevent myocardial injury and to minimize the risk of patent IMA injury.

Endovascular Control of Patent Internal Thoracic Artery Graft in Aortic Valve Surgery

Aortic valve replacement in patients who underwent previous coronary artery bypass with a patent internal thoracic artery is often a challenge because of the risk of graft injury during dissection or difficulties to obtain optimum myocardial protection. Different approaches to myocardial protection or internal thoracic graft dissection and control have been described. Endovascular control of the internal thoracic graft by an angioplasty balloon catheter positioned in the operating room before the operation can be a safe and simple alternative. We report the case of a patient who underwent this technique for aortic valve replacement.

Aortic valve replacement in a patient with a patent internal thoracic artery graft

Myocardial protection in patients requiring a second open-heart surgical procedure after coronary artery bypass grafting, especially when there is a patent left internal thoracic artery graft to the left anterior descending coronary artery, remains controversial. We present the case of a patient in whom aortic valve replacement was undertaken 18 months after coronary artery revascularization. Unusual features included beating-heart aortic valve replacement with continuous retrograde coronary sinus perfusion and avoidance of dissection of the patent grafts, including the left internal thoracic artery and a saphenous vein graft.

A technique for aortic valve replacement on the beating heart with continuous retrograde coronary sinus perfusion with warm oxygenated blood

The protection of ventricular myocardium in aortic valve operations is always an issue because those hearts do not tolerate global ischemia well. A technique of aortic valve replacement is described involving continuous retrograde coronary sinus perfusion with warm oxygenated blood used in 34 patients to date without any complications. This technique maintains a beating heart throughout the procedure.