Chang Hu Choi

Surgical Planning by 3D Printing for Primary Cardiac Schwannoma Resection

We report herein a case of benign cardiac schwannoma in the interatrial septum. A 42-year-old woman was transferred from a clinic because of cardiomegaly as determined by chest X-ray. A transthoracic echocardiography and chest computed tomography examination revealed a huge mass in the pericardium compressing the right atrium, superior vena cava (SVC), left atrium, and superior pulmonary vein. To confirm that the tumor originated from either heart or mediastinum, cine magnetic resonance imaging was performed, but the result was not conclusive. To facilitate surgical planning, we used 3D printing. Using a printed heart model, we decided that tumor resection under cardiopulmonary bypass (CPB) through sternotomy would be technically feasible. At surgery, a huge tumor in the interatrial septum was confirmed. By incision on the atrial roof between the aorta and SVC, tumor enucleation was performed successfully under CPB. Pathology revealed benign schwannoma. The patient was discharged without complication. 3D printing of the heart and tumor was found to be helpful when deciding optimal surgical approach.

Bronchial Artery Aneurysm Presenting as Hematemesis and Mediastinal Hemorrhage

Hematemesis is a rare manifestation of a ruptured bronchial artery aneurysm (BAA) in the mediastinum. It is difficult to diagnose a ruptured BAA presenting as hematemesis, because it can be confused with other diseases, such as Boerhaave’s syndrome, variceal disease, or a perforated ulcer. In this report, we describe a case of BAA resulting in hematemesis and mediastinal hemorrhage.

Early and Mid-term Changes of the Distal Aorta after Total Arch Replacement for Acute Type A Aortic Dissection

Background Total arch replacement (TAR) is being more widely performed due to recent advances in operative techniques and cerebral protective strategies. In this study, the authors reviewed the relationship between TAR and early- and mid-term changes of the false lumen after TAR in acute type A aortic dissection. Materials and Methods Twenty-six patients (aged, 54.7±13.3 years) who underwent TAR for acute type A dissection between June 2004 and February 2012 were reviewed. The relationship between the percentage change in the aortic diameter and the false lumen patency status was assessed by examining the early and late postoperative computed tomography imaging studies. Results There were two in-hospital mortalities, one late death, and three follow-up loses. The mean follow-up duration for the final 21 patients studied was 54±19.0 months (range, 20 to 82 months). The incidence of false lumen thrombosis within 2 weeks of surgery in the proximal, middle, and distal thoracic aorta, and the suprarenal and infrarenal abdominal aorta were 67%, 38%, 38%, 48%, and 33%, respectively, and 57%, 67%, 52%, 33%, and 33% for those examined at a mean of 49±18 months after surgery, respectively. The false lumen regressed in 11 patients (42.3%). The aortic diameters were larger in the patients with a patent false lumen than those with a thrombosed false lumen at all levels of the descending aorta (p<0.05). Conclusion TAR and a more complete primary tear-resection can be accomplished with a relatively low-risk of morbidity and mortality. Enlargement of the distal aorta significantly correlated with the false lumen patency status.

Age-related accumulation of advanced glycation end-products-albumin, S100β, and the expressions of advanced glycation end product receptor differ in visceral and subcutaneous fat.

Visceral fat induces more inflammation by activating macrophages than subcutaneous fat, and inflammation is an underlying feature of the pathogeneses of various diseases, including cardiovascular disease and diabetes. Advanced glycation end products (AGEs), S100β, and their receptors, the receptor for advanced glycation end products (RAGE), lead to macrophage activation. However, little information is available regarding the differential accumulations of AGE-albumin (serum albumin modified by AGEs), S100β, or expressions of RAGE in different adipocyte types in fat tissues. In this study, the authors investigated whether age-related AGE-albumin accumulations S100β level, and RAGE expressions differ in subcutaneous and visceral fat tissues. Subcutaneous and visceral fat were harvested from 3- and 28-week-old rats. Macrophage activation was confirmed by Iba1 staining, and AGE-albumin accumulations and RAGE expressions were assessed by confocal microscopy. S100β were analyzed by immunoblotting. It was found that activated macrophage infiltration, AGE-albumin accumulation, and S100β in visceral fat was significantly greater in 28-week-old rats than in 3-week-old rats, but similar in subcutaneous fat. The expression of RAGE in visceral fat was much greater in 28-week-old rats, but its expression in subcutaneous fat was similar in 3- and 28-week-old rats. Furthermore, inflammatory signal pathways (NFκB, TNF-α) and proliferation pathways (FAK) in visceral fat were more activated in 28-week-old rats. These results imply that age-related AGE-albumin accumulation, S100β, and RAGE expression are more prominent in visceral than in subcutaneous fat, suggesting that visceral fat is involved in the pathogenesis of inflammation-induced diseases in the elderly.

Which risk factors of sternal wound dehiscence should be considered to evaluate the efficacy of water-soluble polymer wax for sternal healing?

We have read the great article by Vestergaard and colleagues [1], which showed that water-soluble polymer wax (WSW) for topical hemostasis on the sternum is better than bone wax (BW). Bone healing was impaired in the BW group more than in the WSW group [1]. In this study, 64% of patients underwent coronary artery bypass grafting (CABG) [1]. Because harvesting the internal thoracic artery for CABG could be associated with sternal wound dehiscence [2], we would like to know whether the proportions of CABG in both the WSW and BW groups were significantly different. Sternal dehiscence is associated with many risk factors such as osteoporosis, obesity, chronic obstructive pulmonary disease, smoking, renal failure, and diabetes [2, 3]. Although the authors addressed the limitation that perfect randomization between the WSW and BW groups was impossible for ethical reasons [1], we believe that the proportion of several risk factors of sternal wound healing such as diabetes, chronic obstructive pulmonary disease, and smoking should be described in both the WSW and BW groups. If the proportions of risk factors are different between groups, it is difficult to say that WSW is better for sternal wound healing than BW. The authors stated that only 2 surgeons were engaged in the study to minimize the variation in sternal closure technique [1]. The key factor for preventing sternal wound dehiscence is stable sternal approximation [4]. Because wiring technique and number of wires could affect sternal approximation [5], we would like to know whether there are differences in the wiring technique or number of wires for sternal fixation in both the WSW and BW groups.

Can the female gender influence risk factor identification for aortic valve surgery

We have read the interesting article by Elmistekawy et al. [1], which showed that preoperative haemoglobin (Hb) was an independent predictor of mortality after aortic valve replacement (AVR) [1]. Although the authors defined that anaemia depends on gender and showed no difference in the incidence of preoperative anaemia between both males and females [1], we believe that gender should be considered a confounder in assessing preoperative Hb as a risk factor for AVR. Several studies showed that female AVR patients have a worse preoperative risk profile than males [2]. Whether gender is an independent risk factor of mortality after AVR is controversial. Several studies showed that female gender was an independent predictor in the AVR population for risk-adjusted 30-day mortality [2], but others failed to show the association between gender and mortality after AVR [3]. In these aspects, gender could be a confounder, while the association between preoperative Hb and mortality after AVR is evaluated. The authors showed that mortality was significantly higher with lower levels of preoperative Hb, with threshold effect at Hb of 120 g/l [1]. We would like to know whether the threshold effect was the same in both genders. Although baseline and nadir haematocrit were lower in females than males, females had a lower relative risk of mortality than males at lower nadir haematocrit [4]. In other words, females have better tolerance to haemodilution than males during cardiopulmonary bypass [4]. In this aspect, we believe that the threshold effect of preoperative Hb on mortality after AVR may differ between males and females. van Straten et al. [5] showed that preoperative low Hb level is an independent risk factor for late mortality, but not for early mortality in patients undergoing isolated AVR. The authors described that the association between preoperative low Hb level and early mortality after heart surgery is more remarkable in coronary artery bypass surgery (CABG) than AVR, because the pathophysiological adverse effects of anaemia are more marked in the presence of coronary artery disease [5, 6]. Elmistekawy et al. [1] reported that the concomitant procedures were equally distributed between the two groups, so the conclusion that mortality of AVR is affected by preoperative Hb is still valid in the appendix section. We think the number of concomitant CABG case might affect the result of study, because it can be a confounder.

Prosthetic Grafting and Arteriovenous Fistula for the Surgical Management of a Common Femoral Vein Injury Using a Staged Approach

A 27-year-old female patient was referred due to an edematous left lower extremity. Both saphenous veins had been ablated with an endovenous laser procedure used to treat varicose veins. Venography revealed that the left common femoral vein had been divided and that thrombosis was present at the site of division. No veins were available around the thighs. The patient was treated using a staged procedure. During the first stage, a ringed polytetrafluoroethylene graft was used to repair the common femoral vein, and an arteriovenous fistula was constructed from the femoral artery to the graft using a short segment of cephalic vein to increase graft patency. The edema was relieved postoperatively and the graft was patent. During the second stage, which was performed 6 months later, the fistula was occluded by coil embolization. The staged procedure described herein provides an alternative for venous reconstruction when autologous vein is unavailable.

Which Variables Should be Considered as Confounders of p38-Mitogen Activated Protein Kinase Activation Measurements?

Pectus excavatum repair in adults has traditionally been performed through an open approach using a modified Ravitch repair, with excellent long-term results [1]. A minimally invasive approach, the Nuss procedure, was introduced in 1998 for pectus repair in children [2]. The Nuss procedure has been used in adult patients with pectus excavatum, with conflicting results related to an increase in bar dislodgement, significant pain, less than perfect cosmetic results, and increased recurrence after bar removal. Therefore controversy exists about which technique is most appropriate for adults with primary and recurrent pectus deformities. In 2009, we published a series of 41 adult patients who underwent operative treatment for primary and recurrent pectus deformities within the Emory Healthcare System from 1999 through 2006; 13 cases (32%) were reoperations, and the median patient age was 26 years (range, 16–46 years). Eight patients (62%) had undergone a Nuss procedure with a pectus index (PI) greater than 4.0 and an asymmetrical defect. Bar removal was at a median of 18 months (range, 14–36 months) after placement. Because of those poor results, we suggested that when adults have a PI greater than 4.0 and an asymmetrical defect, they are at a greater risk of recurrence after a Nuss procedure and should undergo an open modified Ravitch repair [3]. In their Letter to the Editor, Oncel and colleagues [4] noted that our recommendation that patients with a PI greater than 4.0, an asymmetrical defect, and calcified costal cartilages should not undergo a Nuss procedure for correction of pectus excavatum is contrary to their practice of successful Nuss procedures, in which “most patients with a pectus index of 6.0” and is superior to open surgical techniques in every aspect. Oncel and colleagues [4] referenced an article from their institution published in 2013 [5]. That series of 77 patients with pectus deformities was from 2004 through 2011 and they underwent repair with an open Ravitch procedure and a K-wire for posterior sternal support. The mean age of their patients was 17 years (range, 10–22 years), and 52% of them were younger than 17 years of age. Follow-up was by telephone only (at 3–36 months) and was available in only 81% of patients; results were good or excellent. The recurrence rate was 4.8%. Oncel and colleagues [4] stated

Which Variables Should be Considered as Confounders of Florescence Intensity During Indocyanine Green Bronchoscopy

1. Bleiziffer S, Eichinger WB, Hettich I, et al. Prediction of valve prosthesis-patient mismatch prior to aortic valve replacement: which is the best method. Heart 2007;93:615–20. 2. Hernandez-Vaquero D. Patient prosthesis mismatch in adult congenital heart disease. Heart 2016;102:89–90. 3. Swinkels BM, de Mol BA, Kelder JC, Vermeulen FE, ten Berg JM. Prosthesis-patient mismatch after aortic valve replacement: effect on long-term survival. Ann Thorac Surg 2016;101:1388–94.

Should the gender and age of an animal be considered for studies on postconditioning

perfusion cannula. Generally we agree with Mariani and colleagues: a full percutaneous approach can lower cannulation site complications, especially bleeding, during perfusion. However, in situations where a safe (ie, ultrasound or angiographically controlled) insertion of a distal perfusion cannula is not possible or if the perfusion provided by such is not sufficient, the presented surgical technique can be helpful.We do not agreewith the statement that the open technique would bear higher risks for dissection, laceration, thrombosis, embolization, arteriovenous fistula compared with the percutaneous technique. In our experience, the contrary is the case. This is the reason we insist on a safe and controlled punction and insertion for both primary and distal perfusion cannulas. Infection of the prosthesis could theoretically be an issue, however the rather short duration of arteriovenous perfusion and the subsequent removal of the long prosthesis minimize this risk. In any case, the cannulation site is monitored by standardized clinical protocols several times a day. Both techniques described in our technical reports should be perceived as additional elements in the armamentarium of a cardiovascular surgeon. The more alternatives we have, the better we can serve our patients, especially in critical situations.