Every rose has its thorns
Jim DiNardo MD, Viviane Nasr MD, Lindsey Loveland Baptist, MD, Susan Nicolson MD
After reading today’s cardiac PAAD, I have to admit I did not understand the new biventricular conversion “plumbing” nor could I find a good image using a Google search. I asked Lindsey Loveland Baptist, one of our cardiac PAAD reviewers for help and this is what she sent me:
LV recruitment – catch all term for a number of interventions aimed at making a small LV or Left sided structures larger and increasing EF, including: Resection of EFE (endocardial fibroelastosis), Mitral valvuloplasty, Aortic valvuloplasty, Atrial septal defect restriction, Transcatheter interventions: Addition of accessory pulmonary blood flow - increase pulmonary venous return and LV preload
Biventricular conversion –
I watched the video that was linked in the article. The Fontan is completely taken down and the IVC is again anastomosed to the RA. Same with the Glenn – totally taken down and the right SVC is re-anastomosed to the RA. If there is a LSVC, (as in the video) it was connected via tube graft to the RA. Aortic outflow was optimized, main pa outflow optimized.
This article was helpful - Sitaram M. Emani, Doff B. McElhinney, Wayne Tworetzky, Patrick O. Myers, Brian Schroeder, David Zurakowski, Frank A. Pigula, Gerald R. Marx, James E. Lock, Pedro J. del Nido: Staged Left Ventricular Recruitment After Single-Ventricle Palliation in Patients With Borderline Left Heart Hypoplasia, Journal of the American College of Cardiology, Volume 60, Issue 19, 2012, Pages 1966-1974,
Myron Yaster MD
ORIGINAL ARTICLE
Doulamis IP, Marathe SP, Piekarski B, Beroukhim R, Marx GR, del Nido PJ, Emani SM: Biventricular Conversion After Fontan Completion: A Preliminary Experience; J Thorac Cardiovasc Surg. 2021 May 4;S0022-5223(21)00761-3. doi: 10.1016/j.jtcvs.2021.04.076. Online ahead of print. PMID: 34045059
COMMENTARY
Karamlou T. Biventricular conversion: A decade of data delivers more debate. J Thorac Cardiovasc Surg. 2021 May 25:S0022-5223(21)00872-2. doi: 10.1016/j.jtcvs.2021.05.028. Online ahead of print. PMID: 34127278
That the combined expertise of professionals in the field of CHD developed and refined an approach to provide long-term survival, in the form of the Fontan palliation, for children born with one ventricle is truly remarkable. Nonetheless, over time it has become increasingly apparent that Fontan failure occurs as the long term consequence of elevated systemic venous pressure ( 2-3 times normal), non-pulsative pulmonary blood flow, and a chronically volume underloaded ventricle exposed to high afterload 1,2. Fontan failure, as rigorously defined, is death, heart transplantation, Fontan takedown or conversion, protein-losing enteropathy (PLE), plastic bronchitis, or New York Heart Association functional class III or IV at follow-up. In addition, it has recently been recognized that Fontan associated liver disease (FALD) is highly prevalent in the Fontan population and is a significant mortality risk factor 3. Obviously, Fontan failure negatively impacts end organ function and quality of life.
Given this harsh reality, there has been increasing interest in conversion of suitable Fontan patients to a biventricular circulation based on prior experience staging children with borderline left heart structures to a biventricular repair 4. In this PAAD we critique a retrospective analysis of 23 patients of median age 10 (7.5-13) years who had takedown of Fontan circulation that existed for more than 6 years and conversion to biventricular circulation at a single center from September 2007 to April 2020 5. In this study, failing Fontan physiology was defined as Fontan circulation pressure >15 mm Hg and/or the presence of associated complications. Indications for conversion included failing Fontan physiology in 15 (65%) and elective takedown in 8 (35%). Biventricular conversion (BiVC ) in 17 patients included takedown of the Fontan circulation and redirection of the blood flow from left ventricle to the aorta and from right ventricle to the pulmonary arteries with atrial and ventricular septation. The left ventricle was used as the systemic ventricle in all cases. Staged BiVC (S-BiVC) in 6 patients was defined as a patient with Fontan circulation who received a recruitment procedure before Fontan takedown and complete BiVC. Biventricular conversion with or without staged ventricular recruitment led to a significant increase in indexed end-diastolic volume (EDV), indexed end-systolic volume (ESV), and ventricular mass of the nondominant ventricle (14 right, 9 left ventricle). The overall, 3-year reoperation-free survival was 86.7%. Two-year survival for children who underwent elective biventricular conversion was 100%, whereas 2-year survival rate for patients with a failing Fontan circulation was 72.7%. The most common parameters used to determine primary versus staged approach were EDV of 62.5 mL/m2 and ESV of 17.5 mL/m2. At a minimum LV end-diastolic volume > 30 mL/m2 was considered adequate to be considered for BiVC in the absence of endocardial fibroelastosis (EFE) and LV end-diastolic volume > 45 mL/m2 was considered adequate in the presence of EFE.
At first glance these results are encouraging but there is reason to be cautiously optimistic. The establishment of BiV circulation was associated with a non-trivial reintervention rate (11/23 patients) for surgical or catheter-based reintervention on the right ventricular outflow tract, LVOT, coronary arteries, and pulmonary arteries. In addition, given the smaller than normal LVEDV and the inherent diastolic dysfunction associated with EFE there must be concern that BiVC for Fontan patients trades elevated systemic venous pressure for elevated pulmonary venous pressure and the risk for development of post-capillary pulmonary hypertension and secondary development of precapillary hypertension. Obviously, this would seriously impact quality of life and in the worst-case scenario this would preclude consideration for subsequent heart transplantation.
The development and refinement of the Fontan palliation has given countless children the opportunity to pursue a meaningful life with a relatively high functional capacity. We are now acutely aware that this rose has it thorns. Imagination and the courage to innovate has been a hallmark of congenital cardiac care. We should move cautiously forward recognizing the thorns of the newest variety of rose as we seek to improve on our past successes.
References
1. Rychik J. The Relentless Effects of the Fontan Paradox. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu 2016;19:37–43.
2. Rychik J, Atz AM, Celermajer DS, Deal BJ, et al. Evaluation and Management of the Child and Adult With Fontan Circulation: A Scientific Statement From the American Heart Association. Circulation 2019;26:CIR0000000000000696.
3. Emamaullee J, Zaidi AN, Schiano T, Kahn J, Valentino PL, Hofer RE, Taner T, Wald JW, Olthoff KM, Bucuvalas J, Fischer R. Fontan-Associated Liver Disease: Screening, Management, and Transplant Considerations. Circulation 2020;142:591–604.
4. Herrin MA, Zurakowski D, Baird CW, Banka P, Esch JJ, Del Nido PJ, et al. Hemodynamic parameters predict adverse outcomes following biventricular conversion with single-ventricle palliation takedown. J Thorac Cardiovasc Surg. 2017;154:572-82.
5. Doulamis IP, Marathe SP, Piekarski B, Beroukhim RS, Marx GR, Nido PJ del, Emani SM. Biventricular conversion after Fontan completion: A preliminary experience. J Thorac Cardiovasc Surg 2021.