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tality rate (N.=2), no significant associations between patients’ preoperative or intraoperative characteristics and outcomes were found. The current study shows that patients with isolated aneurysms of the ascending and proximal and total arch aorta have excellent outcomes following elective repair at an experienced aorta center. We have previously reported the incidence of the postoperative complications is higher during emergent/urgent repair of acute aortic dissection,2 suggesting the benefit of prophylactic aortic aneurysm repair. Concern for elective patients’ risk of postoperative complications must be balanced with the benefit they receive from reducing the risk of later aortic events (AD or rupture). Current guidelines suggest patients’ prognosis improves when elective aortic surgery is performed when the aortic diameter is 55 mm or higher (except with connective tissue diseases such as Marfan syndrome or strong family histories).3 In this study, there were patients with a family history or strong desire for repair that had aortic diameters less than 55 mm, and postoperative outcomes were excellent. This finding highlights the postoperative morbidity profile for contemporary elective aorta repair is acceptable. The baseline maximal aortic diameter has been found to be the only predictive factor of AD or rupture that is associated with a high rate of mortality.3 Patients with aortic diameters of 50 mm are at risk of 5.5-8% of aortic event within one-year; whereas, this rate increases to 9.3-15.6% when aortic diameters reach to 60 mm. It has also been suggested that aortic diameter should be adjusted by patients’ body size, age, and sex that is reported as “aortic size index”; however, Kim et al. did not find any significant difference between aortic size index and aortic diameter’s accuracy in prediction of aortic events.3 Importantly, patients with ascending aorta or aortic arch aneurysm are often younger than patients with descending or thoracoabdominal aneurysms,4 suggesting an increased risk of lifelong aortic events. Therefore, a safe prophylactic operation in patients with ascending aorta or aortic arch aneurysm in an elective setting could prevent aortic events and their fatal consequences. Some studies have reported higher rates of in-hospital and 30day mortality in patients with elective surgery; though that may be due to increased comorbidities when the aortic diameter reaches 5.5 cm, or from concomitant procedures (valve, CABG, descending aortic repair, and elephant trunk).5 However, in all of these studies mortality rate in an elective setting is much lower than emergent surgery. Patients with prior cardiac surgery are at especially high risk for emergent repair of dissection, reoperation for emergent dissection was found as a predictor for an in-hospital mortality of 38.7% (OR=2.9);2 whereas it was only 3.3% in the current study with almost the same sample size. This shows that elective aortic repair maybe especially important in REDO patients given the added complexity of that procedure.
Seyed H. AALAEI-ANDABILI 1, 2, Tomas MARTIN 1, Philip HESS 3, Teng LEE 1, George ARNAOUTAKIS 1, Thomas M. BEAVER 1 * 1Division of Thoracic and Cardiovascular Surgery, Department of Surgery, University of Florida, Gainesville, FL, USA; 2Division of Cardiology, Department of Medicine, University of Florida, Gainesville, FL, USA;
152
3Division
of Thoracic and Cardiovascular Surgery, Department of Surgery, Indiana University, Indianapolis, IN, USA
*Corresponding author: Thomas M. Beaver, Division of Thoracic and Cardiovascular Surgery, University of Florida, PO Box 100129, Gainesville, FL 32610, USA. E-mail:
[email protected]
References 1. Feldman M, Shah M, Elefteriades JA. Medical management of acute type A aortic dissection. Ann Thorac Cardiovasc Surg 2009;15:286–93. 2. Klodell CT, Karimi A, Beaver TM, Hess PJ, Martin TD. Outcomes for acute type A aortic dissection: effects of previous cardiac surgery. Ann Thorac Surg 2012;93:1206–12. 3. Kim JB, Kim K, Lindsay ME, MacGillivray T, Isselbacher EM, Cambria RP, et al. Risk of rupture or dissection in descending thoracic aortic aneurysm. Circulation 2015;132:1620–9. 4. Davies RR, Gallo A, Coady MA, Tellides G, Botta DM, Burke B, et al. Novel measurement of relative aortic size predicts rupture of thoracic aortic aneurysms. Ann Thorac Surg 2006;81:169–77. 5. Safi HJ, Miller CC 3rd, Lee TY, Estrera AL. Repair of ascending and transverse aortic arch. J Thorac Cardiovasc Surg 2011;142:630–3. Conflicts of interest.—The authors certify that there is no conflict of interest with any financial organization regarding the material discussed in the manuscript. Congresses.—The study was presented at the American Association for Thoracic Surgery aortic symposium, May 12th-16th, 2016, New York, NY, USA. Article first published online: May 22, 2018. - Manuscript accepted: May 16, 2018. - Manuscript revised: April 19, 2018. - Manuscript received: September 15, 2017. (Cite this article as: Aalaei-Andabili SH, Martin T, Hess P, Lee T, Arnaoutakis G, Beaver TM. Even redo ascending aorta replacement has low mortality in elective setting. J Cardiovasc Surg 2019;60:150-2. DOI: 10.23736/S00219509.18.10230-8)
© 2018 EDIZIONI MINERVA MEDICA Online version at http://www.minervamedica.it The Journal of Cardiovascular Surgery 2019 February;60(1):152-4 DOI: 10.23736/S0021-9509.18.10522-2
Abnormal blood flow and wall shear stress are present in corrected aortic coarctation despite successful surgical repair Coarctation of the aorta (CoA) is a complex and relatively common congenital cardiovascular disease. Although surgical intervention is the preferred treatment modality for infants with CoA and is associated with low rates of early morbidity and mortality, surgical repair does not restore the native anatomy and hemodynamic performance of the aorta. Abnormal aortic geometry after surgical repair of aortic coarctation (CoA) may cause changes
The Journal of Cardiovascular Surgery
February 2019
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This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies (either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo, or other proprietary information of the Publisher.
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LETTERS TO THE EDITOR
in blood flow patterns and result in altered aortic hemodynamics, leading to aortic wall tissue degeneration. Time-resolved 3-dimensional (3D) phase contrast MRI with three-directional velocity encoding, also known as 4-dimensional (4D) flow MRI, is a novel imaging modality that is capable of measuring blood flow in the three principal directions and as a function of time, allowing for the visualization and quantification of blood velocity in the aorta.1 In addition, volumetric aortic velocity vector fields measured with 4D flow MRI can be used to calculate novel hemodynamic parameters such as wall shear stress (WSS), the tangential force of blood flow on the endothelial cells. WSS is believed to be an important marker for vessel wall remodeling and may play a crucial role in recoarctation or aneurysm formation in CoA patients. In a recent study among patients with BAV disease, histological analysis revealed that aortic tissue subject to increased WSS results in increased deregulation of the aortic extracellular matrix and degeneration of elastic fibers, a process that may contribute to the development of late aortic dilatation or late aneurysm formation.2 We have evaluated aortic blood flow and WSS patterns in adults after CoA repair in childhood using 4D flow MRI. Thirty-nine CoA patients with a history of corrective surgery for CoA during childhood (age at intervention ≤17 years) and no clinical signs of recoarctation underwent 4D flow MRI, contrastenhanced magnetic resonance angiography (CE-MRA) and transthoracic echocardiography (TTE) at our institution. In addition, 17 healthy age- and gender-matched volunteers with no history of cardiovascular disease or surgery were enrolled. The institutional review board approved the study and all subjects provided informed consent. All study participants underwent cardiac and respiratory-gated sagittal 4D flow MRI of the thoracic aorta on a 3.0 Tesla Ingenia scanner (Philips Healthcare, Best, the Netherlands) with spatial and temporal resolution of 2.5 mm3 and ±42 ms, TE/TR/FA of 2.1 ms/3.4 ms/8° and k-t PCA acceleration of
8 (Figure 1A, B). The data was corrected for eddy currents and velocity aliasing as previously described.3 The thoracic aorta was segmented (Mimics, Materialize, Leuven, Belgium) from timeaveraged phase contrast magnetic resonance angiography images created by multiplication of the magnitude with the absolute velocity images. The peak systolic time frame, defined by the time frame with the highest velocity averaged over the segmentation, was used for WSS calculations. Peak systolic hemodynamic parameters (mean/peak velocity, WSS) and vessel diameters were compared between two regions of interest, at and distal to the CoA site (Figure 1C-F).4 A cohort-averaged 3D WSS map, created from the volunteer data, was used to make velocity and WSS “heat maps” of the CoA patients to delineate abnormally elevated velocity and WSS as previously described.5 Furthermore, 4D flow MRI derived blood flow velocities vs. aortic diameters were compared with TTE vs. CE-MRA. Compared to healthy volunteers, abnormally elevated velocity was seen in 64% and abnormally elevated WSS was observed in 69% of patients. 4D flow MRI derived CoA diameters negatively correlated with the mean WSS (R=-0.73, P
