Aortic Valve Replacement With On-Pump Beating Heart Technique

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.

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.

Donor heart preservation in an empty beating state under mild hypothermia

BACKGROUND

Cardiac surgery during an empty beating heart state has proven to be beneficial in myocardial protection. Based on this, we hypothesized that maintaining this state for donor heart preservation would have the same efficacy and a prolonged preservation period.

METHODS

Part 1: 12 pigs were divided into two groups (n = 6 per group). Donor hearts were preserved in group A by perfusion with leukocyte-depleted blood in the beating state, and in group B, in the traditional hypothermic static state with University of Wisconsin solution. After 8 hours, myocardial samples were obtained to detect myocardial edema, adenosine triphosphate, and ultrastructure. Part 2: 12 donor-recipient swine pairs were randomly allocated to either beating heart preservation with perfusion (group C) or traditional static preservation (group D). Donor hearts were stored for 8 hours after isolation, followed by implantation into recipient animals. Implanted hearts recovered for 120 minutes in an empty and beating state followed by 30 minutes in a working state, after which cardiac function was measured.

RESULTS

After preservation, myocardial adenosine triphosphate levels in group A were significantly higher than in group B. However, myocardial water content was not significantly different between these two groups. The damage of myocardial ultrastructure in group A was slight compared with that of group B. The experimental transplant group C showed excellent heart function after implantation when compared with group D.

CONCLUSIONS

Our study reveals greater effects of donor heart preservation in a beating state rather than simply with hypothermic storage in University of Wisconsin solution.

Surgical correction of ruptured aneurysms of the sinus of Valsalva using on-pump beating-heart technique

BACKGROUND

Rupture of aneurysms of the sinus of Valsalva results in abrupt onset of congestive heart failure. On-pump beating-heart surgery may reduce cardiac impairment by maintaining coronary blood flow and avoiding cardioplegia. Herein, we report the operative correction of thirty-one patients of ruptured aneurysms of the sinus of Valsalva, using the on-pump beating-heart technique.

METHODS

Thirty-one patients with ruptured aneurysms of the sinus of Valsalva underwent operative corrections using the on-pump beating-heart technique. In patients with fistula diameter less than 1 cm and no aortic regurgitation, the aorta was unclamped throughout cardiopulmonary bypass(CPB) while receiving antegrade heart perfusion. In remainder of patients, retrograde perfusion was used.

RESULTS

After intracardiac manipulation was complete and the nasopharyngeal temperature was raised to 36-37 degrees C, the patients were smoothly weaned off CPB. There were no early or late postoperative deaths. All patients were in New York Heart Association functional class I at follow-up (range, 0.5-1 year). Mild-to-moderate aortic valve regurgitation was observed in one patient. No recurrence of the left-to-right shunt from ruptured aneurysms of the sinus of Valsalva was observed.

CONCLUSIONS

Beating heart on pump allows adequate examination of the aortic lesion under near-physiologic conditions, allows decrease in ischemia-reperfusion injury and potentially decreases the risk of serious or fatal rhythm disturbances. On-pump beating-heart technique for repair of ruptured aneurysm of sinus of Valsalva is feasible and promising. Antegrade heart perfusion is suitable for patients with a fistula diameter <1 cm and no aortic regurgitation, and retrograde perfusion is suitable for the others.

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.