Bidirectional Glenn shunt with tricuspid valve resection in patients with infective endocarditis

From the Departments of Anesthesiology, and Surgery, National Taiwan University Hospital, Taipei, Taiwan. Disclosures: The authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest. Received for publication Nov 22, 2021; accepted for publication March 30, 2022; available ahead of print April 2, 2022. Address for reprints: Shu-Chien Huang, MD, PhD, Department of Surgery, National Taiwan University College of Medicine and National University Hospital, 7 Chung-Shan South Rd, Taipei, 10002, Taiwan (E-mail: cvshuang@gmail.com). JTCVS Techniques 2022;13:58-61 2666-2507 Copyright 2022 The Author(s). Published by Elsevier Inc. on behalf of The American Association for Thoracic Surgery. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). https://doi.org/10.1016/j.xjtc.2022.03.002 RV dysfunction after BDG and TV resection.

Video clip is available online.
In drug abusers with infective endocarditis, tricuspid valve (TV) replacement involves high recurrence risk. 1 We have treated these patients with resection of infected tricuspid valve leaflets, TV annular reduction, and bidirectional Glenn shunt (BDG). 2 BDG diverts flow from the superior vena cava (SVC) to pulmonary artery to unload right ventricular (RV). In this study, we report the follow-up of patients with TV endocarditis who received BDG with TV resection.

CLINICAL DATA
We retrospectively reviewed the medical records of 4 patients who received BDG and TV resection. 2 The study was approved by the Ethical Committee of National Taiwan University Hospital (no. 202108103RINA; approval date September 24, 2021). Informed consent was waived because of deidentified patient data. Three patients successfully overcame their drug addiction in 1 year, and 1 patient was lost to follow-up because of criminal problems (Table 1). Their functional status improved. Moreover, patient 1 delivered a healthy baby 5 years after surgery. However, congestive heart failure progressed after delivery. Because her right atrium (RA) and RV were dilated (right ventricular end-diastolic volume index ¼ 117.7 mL/m 2 ), and RV systolic function deteriorated (right ventricular ejection fraction ¼ 39%), her TV was replaced with a 31-mm porcine valve (Hancock II; Medtronic). After TV replacement and RA closure, the SVC was removed from the pulmonary artery and reanastomosed to the RA through continuous suture. She had sinus rhythm afterwards. Her RA and RV regained their normal sizes 2 years after surgery, with improved functional status. Patient 2 experienced exertional dyspnea 4 years after BDG with TV resection. The maximal oxygen consumption was only 9.77 mL/min/kg (37% of the predicted value). Cardiac magnetic resonance imaging revealed severe RA dilatation, mild RV dilatation (right ventricular end-diastolic volume index ¼ 100.96 mL/m 2 ), and preserved RV contractility (right ventricular ejection fraction ¼ 58%) (Video 1). SVC angiography revealed patent BDG with multiple collateral veins from the right subclavian vein to the inferior vena cava (IVC). She received TV replacement with a 33-mm St Jude Medical Epic porcine bioprosthetic valve, and her SVC was reconnected to the RA by using a 22-mm GORE-TEX graft 7 years after first operation. Her RV size normalized in the first year after surgery. She had sinus rhythm and improved exercise function during follow-up. Patient 3 first experienced exertional dyspnea 2 years after BDG and TV resection. Echocardiography revealed patent BDG, severe RA dilation, RV dilatation (RV From the Departments of a Anesthesiology, and b Surgery, National Taiwan University Hospital, Taipei, Taiwan. Disclosures: The authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest.

CENTRAL MESSAGE
BDG unloads the RV volume in acute endocarditis patients after TV resection, but severe tricuspid regurgitation leads to RV dysfunction in the long term. diastolic diameter ¼ 3.9 cm), and left ventricle (LV) compression. Decreased antegrade flow in the right ventricular outflow tract was disclosed because of severe tricuspid regurgitation. Atrial fibrillation was also noted. The dyspnea exacerbated during follow-up; hence, her TV was replaced with a 33-mm SJM Masters Series Mechanical Heart Valve 16 years after the first operation. The SVC was re-anastomosed to the RA with continuous suture. She had sinus rhythm afterwards, and her LV compression was relieved, with improved LV diastolic function.

DISCUSSION
The long-term outcomes of BDG and TV resection in adult patients have limited reference. We previously demonstrated that BDG with TV resection provides a good short-term hemodynamic profile 2 and an adequate observation period for infection control and drug abstinence. However, because of severe tricuspid regurgitation, RV unloading after BDG is insufficient in the long term. TV insufficiency causes blood backflow, which leads to progressive right-side chamber dilatation, function deterioration, and decreased right ventricular outflow tract antegrade flow 3 (Video 1). TV replacement corrects this and improves functional status.
BDG is applied in congenital heart disease with insufficient RV function. 4 BDG failure has several risk factors, such as pulmonary hypertension and elevated left atrial pressure. There was no evidence of pulmonary emboli or pulmonary hypertension in our patients, but all our patients had LV diastolic dysfunction before TV replacement. One patient even had a reduced LV volume due to septal displacement by RV dilatation. Last but not least, the pressure difference in the SVC and IVC could lead to venous collateral circulation, as observed in one of our patients. If venous collateral circulation from the SVC to IVC is significant, the RV workload increases, and BDG lost its unloading function (Figure 1). Because tricuspid insufficiency disappears after TV replacement, RV unloading by using BDG is no longer needed. Thus, we converted one and a half circulation to the biventricular status through the reconnection of the SVC to the RA in all our patients.
In summary, TV resection with BDG can provide a stable hemodynamic condition in the short term and offer an adequate observation period for drug abstinence. In the  long-term follow-up, prosthetic TV replacement and SVC reimplantation are needed in case of severe tricuspid insufficiency and worsened RV function.