A Technical Modification for Establishing Selective Antegrade Cerebral Perfusion during Pulmonary Endarterectomy

Abstract

Pulmonary endarterectomy (PEA) due to chronic thromboembolic pulmonary hypertension (CTEPH) is mainly performed in deep hypothermic circulatory arrest without additional cerebroprotective means. A 49-year-old man was treated by PEA for CTEPH by using selective antegrade cerebral perfusion by advancing the tip of the systemic perfusion cannula into the brachiocephalic trunk. The postoperative course was uneventful.

Keywords

pulmonary arteries - pulmonary endarterectomy - selective antegrade cerebral perfusion

Introduction

Selective antegrade cerebral perfusion (SACP) has emerged as a widely used cerebroprotective technique in proximal thoracic aortic surgery. However, the technique is not routinely used in patients undergoing pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH). We describe a simple technical modification for easily establishing SACP during PEA.

Technique

A 49-year-old man was referred for PEA due to CTEPH. The patient was treated by bilateral PEA in hypothermia at 23°C with lower body circulatory arrest but continuing cerebral perfusion using SACP via redirection of the systemic arterial inflow cannula (22-French Medtronic EOPA Arterial Cannula, Medtronic Inc., Minneapolis, Minnesota, United States) into the brachiocephalic trunk with consecutive snaring of the vessel and additional occlusion of the left common carotid artery as well the left subclavian artery via vessel loops ([Fig. 1]). The ascending aorta was merely clamped for cardioplegia administration. Our protocol includes a flow rate between 7 and 10 mL/kg bodyweight per minute with the perfusate temperature equal to the core temperature. Cerebral monitoring is performed via near-infrared spectroscopy using the Somanetics system (Cerebral Oximeter, Somanetics; Troy, Michigan, United States) showing regular cerebral oxygenation patterns during the SACP period. The postoperative course was uneventful.

Fig. 1 Intraoperative view depicting the 22-French Medtronic EOPA Arterial Cannula advancing into the brachiocephalic trunk with a snare around the vessel. Furthermore, the left common carotid artery and the left subclavian artery are snared with vessel loops. The left pulmonary artery mainstem is already opened.

Comment

PEA due to CTEPH is mainly performed in deep hypothermic circulatory arrest (DHCA) to provide a bloodless surgical field. Recently, DHCA alone has been shown to be noninferior to DHCA with SACP in patients undergoing PEA.[1] However, the benefits of SACP in proximal thoracic aortic surgery have been extensively demonstrated.[2] [3] Thereby, SACP in PEA may well present a means to enable higher circulatory arrest temperatures without increasing risk, thereby reducing hypothermic circulatory arrest time and consecutively bleeding complications associated with deep core temperatures and long DHCA times.

The PEACOG trial as well as many other reports on PEA refers to DHCA as a period of DHCA not exceeding 20 minutes interrupted by a period of 10 minutes of reperfusion between DHCA periods.[1] In other words, antegrade cerebral perfusion (ACP) is used but not in a continuing fashion. This may also well be the reason why the trial did not show any differences regarding cognitive function because DHCA periods always alternated with ACP.

In contrast to proximal thoracic aortic surgery, the ascending aorta and the aortic arch remain unaffected by surgery during PEA except for arterial cannulation. By using a straight cannula as in our case (22-French Medtronic EOPA Arterial Cannula), the tip of the cannula can easily be advanced into the brachiocephalic trunk by tactile control, thereby establishing SACP without additional clamping of the ascending aorta (except for cardioplegia administration) and the distal aortic arch. Without doubt, optimal visibility forms the basis of the surgical result—however, ACP and optimal visibility are not mutually exclusive in our opinion.

Summarizing, this simple technical modification may serve as an adjunct to the armamentarium of the surgeon in performing PEA with SACP to increase the safety margin during systemic circulatory arrest and to decrease DHCA alone–associated collateral injury.

• References

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• 3 Bonser RS, Ranasinghe AM, Loubani M , et al. Evidence, lack of evidence, controversy, and debate in the provision and performance of the surgery of acute type A aortic dissection. J Am Coll Cardiol 2011; 58 (24) 2455-2474

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