Significance of histologic subtype size as a prognostic indicator in stage IA lung adenocarcinoma.

Background: Predicting prognosis is complex due to a unique characteristic in stage IA lung adenocarcinoma. The feature indicated heterogeneous histologic subtype and ground glass opacity (GGO). Many studies demonstrated different prognoses according to histologic subtype or non-GGO lesion. This study aimed to evaluate the clinical outcomes following each histologic subtype size in stage IA lung adenocarcinoma and identify the prognostic impact of each histologic subtype size. Methods: The medical records of 550 patients with pathological stage IA lung adenocarcinoma were reviewed. Histologic subtype size was estimated by multiplying the tumor's maximum diameter by the proportion of each histologic subtype. Univariate and multivariate analyses were conducted to identify the prognostic role of each histologic subtype size in stage IA lung adenocarcinoma. Results: The median age and tumor size were 63 [25-82] years and 1.8 [0.3-3] cm, respectively. Acinar (42.0%) and lepidic (44.4%) were the most common among the predominant subtype. Each subtype size was estimated and re-categorized following the current staging system. The disease-free interval (DFI) was significantly different following each histologic subtype size. Multivariate analysis for DFI revealed more acinar, micropapillary, and solid subtypes and fewer lepidic subtypes with worse prognoses. Conclusions: The prognosis for DFI is determined through a complex process by various variables in stage IA lung adenocarcinoma. Each subtype size has a more prognostic impact than the predominant subtype.

Stem cell laden nano and micro collagen/PLGA bimodal fibrous patches for myocardial regeneration.

BACKGROUND: Although the use of cardiac patches is still controversial, cardiac patch has the significance in the field of the tissue engineered cardiac regeneration because it overcomes several shortcomings of intra-myocardial injection by providing a template for cells to form a cohesive sheet. So far, fibrous scaffolds fabricated using electrospinning technique have been increasingly explored for preparation of cardiac patches. One of the problems with the use of electrospinning is that nanofibrous structures hardly allow the infiltration of cells for development of 3D tissue construct. In this respect, we have prepared novel bi-modal electrospun scaffolds as a feasible strategy to address the challenges in cardiac tissue engineering . METHODS: Nano/micro bimodal composite fibrous patch composed of collagen and poly (D, L-lactic-co-glycolic acid) (Col/PLGA) was fabricated using an independent nozzle control multi-electrospinning apparatus, and its feasibility as the stem cell laden cardiac patch was systemically investigated. RESULTS: Nano/micro bimodal distributions of Col/PLGA patches without beaded fibers were obtained in the range of the 4-6% collagen concentration. The poor mechanical properties of collagen and the hydrophobic property of PLGA were improved by co-electrospinning. In vitro experiments using bone marrow-derived mesenchymal stem cells (BMSCs) revealed that Col/PLGA showed improved cyto-compatibility and proliferation capacity compared to PLGA, and their extent increased with increase in collagen content. The results of tracing nanoparticle-labeled as well as GFP transfected BMSCs strongly support that Col/PLGA possesses the long-term stem cells retention capability, thereby allowing stem cells to directly function as myocardial and vascular endothelial cells or to secrete the recovery factors, which in turn leads to improved heart function proved by histological and echocardiographic findings. CONCLUSION: Col/PLGA bimodal cardiac patch could significantly attenuate cardiac remodeling and fully recover the cardiac function, as a consequence of their potent long term stem cell engraftment capability.

Comparison of clinical results between high grade patterns in stage I lung adenocarcinoma.

BACKGROUND: The histological subtype has been introduced in invasive lung adenocarcinoma. The predominant micropapillary and solid subtypes are categorized as high-grade patterns and provide a worse prognosis. However, the prognostic analysis of high-grade patterns has not previously been fully investigated. Thus, this study aimed to investigate the prognostic role of high-grade patterns in pathological stage I lung adenocarcinoma. METHODS: Patients with stage I lung adenocarcinoma and micropapillary or solid components were reviewed. Clinicopathological features and clinical course were compared in these subtypes, and prognostic factors were analyzed in high-grade patterns. RESULTS: The patients were classified into five groups based on the presence of micropapillary or solid subtypes, namely, micropapillary predominant, solid predominant, both nonpredominant subtypes, only minor micropapillary subtype, and only minor solid subtype present. Disease-free interval was significantly different, and the micropapillary predominant group showed worse disease-free interval (p = 0.001). Contrastingly, the solid predominant group showed significantly worse overall survival among high-grade patterns (p = 0.035). The multivariate analysis revealed an association between smoking, micropapillary predominant, blood vessel invasion, and visceral pleural invasion with recurrence and more association between solid predominant and visceral pleural invasion with overall survival. CONCLUSIONS: Clinical results were different in stage I high-grade adenocarcinoma. The predominant micropapillary subtype is the independent prognostic factor for recurrence. However, the solid subtype is the significant factor for overall survival. Furthermore, the predominant subtype is the most valuable and independent prognostic factor for predicting recurrence or survival.

Predicting prognosis using a pathological tumor cell proportion in stage I lung adenocarcinoma.

BACKGROUND: Tumor size is a valuable prognostic factor because it is considered a measure of tumor burden. However, it is not always correlated with the tumor burden. This study aimed to identify the prognostic role of pathological tumor proportional size using the proportion of tumor cells on the pathologic report after curative resection in pathologic stage I lung adenocarcinoma. METHODS: We retrospectively reviewed the medical records of 630 patients with pathologic stage I lung adenocarcinoma after lung resection for curative aims. According to the pathologic data, the proportion of tumor cells was reviewed and pathological tumor proportional size was estimated by multiplying the maximal diameter of the tumor by the proportion of tumor cells. We investigated the prognostic role of pathological tumor proportional size. RESULTS: The median tumor size was 2 cm (range: 0.3-4), and the median pathological tumor proportional size was 1.5 (range: 0.12-3.8). This value was recategorized according to the current tumor-node-metastasis (TNM) classification, and 184 patients showed down staging compared with the current stage. The survival curve for disease-free survival using pathological tumor proportional size showed more distinction than the current stage classification. Multivariate analysis revealed that a down stage indicated a favorable prognostic factor. CONCLUSION: Pathological tumor cell proportional size may be associated with prognosis in stage I lung adenocarcinoma. If the pathological tumor proportional size shows a downward stage, it may indicate a smaller tumor burden and better prognosis.

Evaluation of electroporated area using 2,3,5-triphenyltetrazolium chloride in a potato model.

Irreversible electroporation (IRE) is a tissue ablation method, uses short high electric pulses and results in cell death in target tissue by irreversibly permeabilizing the cell membrane. Potato is commonly used as a tissue model for electroporation experiments. The blackened area that forms 12 h after electric pulsing is regarded as an IRE-ablated area caused by melanin accumulation. Here, the 2,3,5-triphenyltetrazolium chloride (TTC) was used as a dye to assess the IRE-ablated area 3 h after potato model ablation. Comparison between the blackened area and TTC-unstained white area in various voltage conditions showed that TTC staining well delineated the IRE-ablated area. Moreover, whether the ablated area was consistent over time and at different staining times was investigated. In addition, the presumed reversible electroporation (RE) area was formed surrounding the IRE-ablated area. Overall, TTC staining can provide a more rapid and accurate electroporated area evaluation.

A supramolecular host-guest interaction-mediated injectable hydrogel system with enhanced stability and sustained protein release.

Injectable hydrogels have been studied as drug delivery systems because of their minimal invasiveness and sustained drug release properties. Pluronic F127, consisting of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers, exhibits thermo-responsive properties and hence is injectable due to its rapid sol-gel transition. Unmodified Pluronic F127-based hydrogels, however, have limited long-term stability and controllable release of drugs entrapped within them. In this study, host-guest interactions between adamantane-conjugated Pluronic F127 (F127-Ad) and polymerized ß-cyclodextrin (CDP) were employed to develop a hydrogel-based protein delivery system. Single or multiple adamantane units were successfully introduced at the termini of Pluronic F127 with a 100% conversion yield, and the synthesized F127-Ad polymer produced a physically crosslinked micelle-packing structure when mixed with CDP. As the number of adamantanes at the terminal ends of Pluronic F127 increased, the critical gelation concentration of F127-Ad/CDP hydrogel decreased from 15 to 6% (w/v). The F127/CDP hydrogel was able to maintain its structure even with lower polymer content, and its injectability improved with a reduction of the hydrogel viscosity. The long-term stability of F127/CDP hydrogels was evaluated in vitro and in vivo, and it was demonstrated that the subcutaneously injected hydrogel did not disintegrate for up to 30 d. Throughout the drug release test using gelatin and insulin as model drugs, it was demonstrated that their release rates could be regulated via complexation between the protein drugs and the ß-cyclodextrin molecules inside the hydrogel. In conclusion, the F127-Ad/CDP hydrogel is expected to be a versatile protein delivery system with controllable durability and drug release characteristics. STATEMENT OF SIGNIFICANCE: Pluronic F127 is one of the widely studied polymeric materials for thermo-sensitive injectable hydrogels due to its high biocompatibility and rapid sol-gel transition. Since the Pluronic F127-based hydrogel has some limitations in its long-term stability and mechanical property, it is inevitable to modify its structure for the application to drug delivery. In this study, mono- or multi- adamantane-conjugated Pluronic F127s were synthesized and mixed with ß-cyclodextrin polymers to form hydrogels with host-guest interaction-mediated micelle-packing structures. The host-guest interaction introduced into the hydrogel system endowed it a sustained protein drug release behavior as well as high durability in vitro and in vivo. By increasing the number of adamantane molecules at the end of the Pluronic F127, both the stability and injectability of the hydrogel could be also modulated.

Significant difference in recurrence according to the proportion of high grade patterns in stage IA lung adenocarcinoma.

BACKGROUND: Patients with early lung cancer are the best candidates for surgical resection. However, those patients with high grade patterns (micropapillary or solid) do not have a good prognosis, even if they have been diagnosed with stage I lung adenocarcinoma. A new modified grading system has been introduced and this study aimed to identify the prognostic role of the new grading system in patients with stage IA lung adenocarcinoma. METHODS: Patients with pathological stage IA lung adenocarcinoma, according to the eighth TNM classification who underwent curative resection, were reviewed. The pathological data of stage IA adenocarcinoma was reviewed 1 (grade 1: lepidic predominant with no or less than 20% of high grade patterns, grade 2: acinar or papillary predominant with no or less than 20% of high grade patterns, grade 3: any tumor with 20% or more of high grade patterns). Prognostic factors were analyzed for disease-free interval (DFI) and overall survival (OS) using Cox proportional models. RESULTS: The medical records of 429 patients with stage IA lung adenocarcinoma were reviewed. DFI (p < 0.001) and OS (p < 0.001) were significantly lower in patients diagnosed with grade 3 compared with grade 1 and grade 2. Multivariate analysis showed that smoking (p = 0.013), value of SUVmax (p = 0.005), lymphovascular invasion (p = 0.004) and grade 3 (p = 0.008) were significant prognostic factors for DFI. CONCLUSIONS: The proportion of high grade patterns showed a different prognosis, even if curative resection had been performed for stage IA adenocarcinoma. This new grading system is more simple and useful in the prediction of a prognosis in patients with stage IA lung adenocarcinoma.

Prognostic impact according to the proportion of the lepidic subtype in stage IA acinar-predominant lung adenocarcinoma.

BACKGROUND: Adenocarcinoma is the most common type of lung cancer and most adenocarcinomas have heterogeneous subtypes. Acinar-predominant adenocarcinoma is the most common. This study aimed to identify the prognostic impact of other mixed histological subtypes in acinar-predominant lung adenocarcinoma. METHODS: The medical records of patients with pathological stage IA acinar-predominant lung adenocarcinoma between January 2010 and April 2016 were reviewed. The patients were divided into two groups according to the proportion of the lepidic subtype, with a cutoff value of 20%, and prognostic factors were analyzed. RESULTS: A total of 215 patients with stage IA acinar-predominant adenocarcinoma were reviewed. The 20% or more lepidic subtype group had a low value of SUVmax (p = 0.001), good differentiation (p < 0.001) and a low incidence of the solid histological subtype (p = 0.016). Recurrence was significantly lower in the 20% or more lepidic subtype group (p = 0.008). The disease-free survival (p = 0.007) and overall survival (p = 0.046) were significantly different between the two groups. Multivariate analysis showed that lymphovascular invasion (p = 0.006) and no or less than 20% lepidic subtype (p = 0.036) were significant prognostic factors for disease-free survival. CONCLUSIONS: The lepidic proportion may be useful to predict recurrence in acinar-predominant stage IA lung adenocarcinoma.

Use of imaging studies to predict postoperative recurrences of primary spontaneous pneumothorax.

BACKGROUND: Bullectomy with pleural procedure is the most effective means of treating primary spontaneous pneumothorax (PSP). However, recurrences after thoracoscopic bullectomy are unexpectedly frequent. Our aim was to identify the premonitory imaging features after thoracoscopic bullectomy that may associate with recurrences in PSP. METHODS: The medical records of all patients undergoing thoracoscopic bullectomy for PSP between January 2013 and September 2016 were subject to review. A total of 154 procedures performed on 147 patients qualified for study. Clinical outcomes and characteristics of patients were reviewed and serial chest radiographies were assessed, analyzing risk factors for postoperative recurrences. RESULTS: Median age of the male-predominant cohort (93.5%) was 19 (range, 15-39) years. Median operative time was 35 min, none reflecting complications. Postoperatively, diaphragmatic tenting was identified in 78 patients (50.6%), and pleural residual cavity was identified by chest radiography in 102 (66.2%). After discharge, remained diaphragmatic tenting (38/154, 24.7%) and pleural residual cavity (52/154, 33.8%) were identified by chest radiography. In univariate analysis, remained diaphragmatic tenting (P=0.026) and length of pleural residual cavity (P=0.024) emerged as risk factors for recurrence; and both reached significance in multivariate analysis (P=0.020 and P=0.018, respectively). CONCLUSIONS: Remained diaphragmatic tenting after thoracoscopic surgery for PSP may be associated with the risk of postoperative recurrence.

Should We Consider the Resected Lung Volume in Primary Spontaneous Pneumothorax?

BACKGROUND: Although bullectomy is the most curative treatment in primary spontaneous pneumothorax (PSP), postoperative recurrence is not uncommon. New bulla formation at the staple line is the most common cause of recurrence. However, the mechanism is not known. We believe that the pressure gradient plays the main role in new bulla formation. A large resection amount induces a prolonged pressure gradient for obliteration of the residual space. This study aimed to identify the association between resected lung volume and recurrence. METHODS: The medical records of patients who underwent video-assisted thoracoscopic surgery (VATS) bullectomy were reviewed between October 2010 and December 2017. A total of 396 patients underwent surgery for spontaneous pneumothorax. The electronic medical records (EMRs) of the patients were reviewed. Patients with secondary spontaneous pneumothorax were excluded. Patients who were diagnosed with emphysema on CT were excluded. Patients with PSP were excluded from the study if the bulla was not located in the apex or if there was no ruptured bulla at the time of the operation. Patients who lacked EMRs were also excluded. We reviewed the medical records of 276 patients. The apical resected lung volume was estimated using a conical volumetric formula with the use of the specimen size. The risk factors for postoperative recurrence were analyzed. RESULTS: The median age was 19 years old (range 13-36). A total of 261 patients were male (94.6%). The median body weight and body mass index (BMI) were 58 kg (range 40-82) and 18.92 (range 15.21-26.47), respectively. In 24 patients, both sides were operated on simultaneously. The resected lung volume was obtained by using a conical volumetric formula, and the value was divided by the BMI value. The median value was 1.43 (0.03-5.67). The median operative time was 35 min (range 15-120). The median postoperative day was 4 (range 2-12). Age (p = 0.006), the value of the resected lung volume divided by BMI (p = 0.003), bilateral bullectomy (p = 0.013) and transverse diameter (p = 0.034) were associated with postoperative recurrence according to the univariate analysis. According to the multivariate analysis, age and the value of the lung volume divided by BMI were significant risk factors for postoperative recurrence. CONCLUSIONS: Younger age and a large resected lung volume and a low BMI are associated with postoperative recurrence after VATS bullectomy for PSP.

Stem cell-loaded adhesive immiscible liquid for regeneration of myocardial infarction.

Myocardial infarction (MI) causes serious loss of cardiac muscle and dysfunction. To restore MI, exogenous stem cells should be efficiently delivered. However, due to severe physical and physiological cardiac environment, recent strategies have faced challenges, including low cell persistence, low integration, and delayed therapeutic effects. Herein, we proposed mesenchymal stem cell (MSC) therapeutic platform using adhesive protein-based immiscible condensed liquid system (APICLS) derived from bioengineered mussel adhesive protein (MAP). With high encapsulation efficiency and survival rate of encapsulated MSCs, APICLS was successfully grafted by intramyocardial injection and distributed throughout the scarred myocardium. Its underwater adhesiveness and biocompatibility fostered integration with damaged tissue, resulting in high cell persistence and maximized paracrine effects. Bioactive molecules released from APICLS with MSCs induced angiogenesis and cardioprotection, delayed cardiac remodeling, reduced fibrosis, and recovered contractive force. Thus, our proposed strategy represents an innovative approach for recovering infarcted cardiac tissues with damaged structural and contractive function.

Comprehensive Examination of Mechanical and Diffusional Effects on Cell Behavior Using a Decoupled 3D Hydrogel System.

Hydrogels possess several physical and chemical properties suitable for engineering cellular environments for biomedical applications. Despite recent advances in hydrogel systems for cell culture, it is still a significant challenge to independently control the mechanical and diffusional properties of hydrogels, both of which are well known to influence various cell behaviors when using hydrogels as 3D cell culture systems. Controlling the crosslinking density of a hydrogel system to tune the mechanical properties inevitably affects their diffusional properties, as the crosslinking density and diffusion are often inversely correlated. In this study, a polymeric crosslinker is demonstrated that allows for the adjustment of the degree of substitution of reactive functional groups. By using this polymeric crosslinker, the rigidity of the resulting hydrogel is controlled in a wide range without changing the polymer concentration. Furthermore, their diffusional properties, as characterized by their swelling ratios, pore diameters, and drug release rates, are not significantly affected by the changes in the degree of substitution. 3D cell studies using this hydrogel system successfully demonstrate the varying effects of mechanical properties on different cell types, whereas those in a conventional hydrogel system are more significantly influenced by changes in diffusional properties.

The Longitudinal Trend of Cardiac Surgery in Korea from 2003 to 2013.

BACKGROUND: The purpose of this study was to investigate longitudinal changes of the utilization of operational and surgical medical care inside and outside a metropolitan area over 10 years, analyzing the residential areas of patients and the locations of medical facilities for major cardiovascular surgery. METHODS: Data analysis was conducted by classifying the addresses of patients and the locations of medical care facilities of metropolitan cities and provinces, using data from the National Health Insurance Corporation from January 2003 to December 2013. RESULTS: There is serious concentration of major heart surgery to medical facilities in Seoul; this problem has not improved over time. There were differences in percentages of surgical procedures performed in the metropolitan areas according to major diseases. In the case of Busan and Daegu provinces, at least 50% of the patients underwent surgery in medical facilities in the city, but there are other regions where the percentage is less than 50%. In the case of provinces, the percentage of surgical procedures performed in medical facilities in Seoul or nearby metropolitan cities is very high. CONCLUSION: Policies to strengthen the regional capabilities of heart surgery and to secure human resources are required to mitigate the concentration of patients in the capital area. Many regional multi-centers must be designated to minimize unnecessary competition among regional university hospitals and activate a win-win partnership model for medical services.

Imbalance in Cardiovascular Surgery Medical Service Use Between Regions.

BACKGROUND: This study uses the relevance index to understand the condition of regional medical service use for cardiovascular surgery and to identify the medical service use imbalance between regions. METHODS: This study calculated the relevance index of 16 metropolitan cities and provinces using resident registration address data from the Ministry of Government Administration and Home Affairs and the 2010-2014 health insurance, medical care assistance, and medical benefits claims data from the Health Insurance Review and Assessment Service. We identified developments over the 5-year time period and analyzed the level of regional imbalance regarding cardiovascular surgery through the relative comparison of relevance indexes between cardiovascular and other types of surgery. RESULTS: The relevance index was high in large cities such as Seoul, Daegu, and Gwangju, but low in regions that were geographically far from the capital area, such as the Gangwon and Jeju areas. Relevance indexes also fell as the years passed. Cardiovascular surgery has a relatively low relevance index compared to key types of surgery of other fields, such as neurosurgery and colorectal surgery. CONCLUSION: This study identified medical service use imbalance between regions for cardiovascular surgery. Results of this study demonstrate the need for political intervention to enhance the accessibility of necessary special treatment, such as cardiovascular surgery.

The Association Between Treatment Frequency and Treatment Outcome for Cardiovascular Surgeries.

BACKGROUND: This study analyzed the association between the volume of heart surgeries and treatment outcomes for hospitals in the last five years. METHODS: Hospitals that perform heart surgeries were chosen throughout Korea as subjects using from the Health Insurance Review and Assessment Service. The treatment outcome of the heart surgeries was defined as the mortality within 30 postoperative days, while the annual volume of the surgeries was categorized. Logistic regression was used as the statistical analysis method, and the impacts of the variables on the heart surgery treatment outcomes were then analyzed. RESULTS: The chance of death of patients who received surgery in a hospital that performed 50 or more surgeries annually was noticeably lower than patients receiving operations from hospitals that performed fewer than 50 surgeries annually, indicating that the chance of death decreases as the annual volume of heart surgeries in the hospital increases. In particular, the mortality rate in hospitals that performed more than 200 surgeries annually was less than half of that in hospitals that performed 49 or fewer surgeries annually. CONCLUSION: These results indicate that accumulation of a certain level of heart surgery experience is critical in improving or maintaining the quality of heart surgeries. In order to improve the treatment outcomes of small hospitals, a support policy must be implemented that allows for cooperation with experienced professionals.

Development of Models for Regional Cardiac Surgery Centers.

BACKGROUND: This study aimed to develop the models for regional cardiac surgery centers, which take regional characteristics into consideration, as a policy measure that could alleviate the concentration of cardiac surgery in the metropolitan area and enhance the accessibility for patients who reside in the regions. METHODS: To develop the models and set standards for the necessary personnel and facilities for the initial management plan, we held workshops, debates, and conference meetings with various experts. RESULTS: After partitioning the plan into two parts (the operational autonomy and the functional comprehensiveness), three models were developed: the 'independent regional cardiac surgery center' model, the 'satellite cardiac surgery center within hospitals' model, and the 'extended cardiac surgery department within hospitals' model. Proposals on personnel and facility management for each of the models were also presented. A regional cardiac surgery center model that could be applied to each treatment area was proposed, which was developed based on the anticipated demand for cardiac surgery. The independent model or the satellite model was proposed for Chungcheong, Jeolla, North Gyeongsang, and South Gyeongsang area, where more than 500 cardiac surgeries are performed annually. The extended model was proposed as most effective for the Gangwon and Jeju area, where more than 200 cardiac surgeries are performed annually. CONCLUSION: The operation of regional cardiac surgery centers with high caliber professionals and quality resources such as optimal equipment and facility size, should enhance regional healthcare accessibility and the quality of cardiac surgery in South Korea.

Projections of Demand for Cardiovascular Surgery and Supply of Surgeons.

BACKGROUND: While demand for cardiovascular surgery is expected to increase gradually along with the rapid increase in cardiovascular diseases with respect to the aging population, the supply of thoracic and cardiovascular surgeons has been continuously decreasing over the past 10 years. Consequently, this study aims to achieve guidance in establishing health care policy by analyzing the supply and demand for cardiovascular surgeries in the medical service area of Korea. METHODS: After investigating the actual number of cardiovascular surgeries performed using the National Health Insurance claim data of the Health Insurance Review and Assessment Service, as well as drawing from national statistics concerning the elderly population aged 65 and over, this study estimated the number of future cardiovascular surgeries by using a cell-based model. To be able to analyze the supply and demand of surgeons, the recent status of new surgeons specializing in thoracic and cardiovascular surgeries and the ratio of their subspecialties in cardiovascular surgeries were investigated. Then, while taking three different scenarios into account, the number of cardiovascular surgeons expected be working in 5-year periods was projected. RESULTS: The number of cardiovascular surgeries, which was recorded at 10,581 cases in 2014, is predicted to increase consistently to reach a demand of 15,501 cases in 2040-an increase of 46.5%. There was a total of 245 cardiovascular surgeons at work in 2014. Looking at 5 year spans in the future, the number of surgeons expected to be supplied in 2040 is 184, to retire is 249, and expected to be working is 309-an increase of -24.9%, 1.6%, and 26.1%, respectively compared to those in 2014. This forecasts a demand-supply imbalance in every scenario. CONCLUSION: Cardiovascular surgeons are the most central resource in the medical service of highly specialized cardiovascular surgeries, and fostering the surgeons requires much time, effort, and resources; therefore, by analyzing the various factors affecting the supply of cardiovascular surgeons, an active intervention of policies can be prescribed for the areas that have failed to meet the appropriate market distributions.

Thoracic and Cardiovascular Surgeons' Perception of the Concentration of Cardiovascular Operations in Seoul Metropolitan Area's Hospitals.

BACKGROUND: The purpose of this study is to evaluate the concentration of cardiovascular surgical procedures in a metropolitan area and investigate the perception of specialists regarding governmental policies to resolve this imbalance. METHODS: From March to May 2015, surveys were distributed to members of the Thoracic and Cardiovascular Surgery Association. The final pool of research subjects consisted of 75 respondents. Subjects were queried regarding the concentration of cardiovascular operations in metropolitan areas, alternatives to the imbalance, and governmental policies to resolve the inequalities. RESULTS: Survey participants responded that South Korea needs governmental policies to alleviate the concentration of cardiovascular surgery patients in large metropolitan hospitals. Participants agreed that the freedom to choose medical institutions and improved accessibility to metropolitan hospitals due to advanced transportation systems were some of the causes for the concentration. A majority (98.7%) of respondents thought establishing thoracic and cardiovascular surgery centers in provinces was an appropriate solution to alleviate the concentration. Thoracic and cardiovascular surgery specialists were ranked as the number one group on which to focus development. CONCLUSION: Developing and carrying out policies to establish thoracic and cardiovascular surgery centers in provinces will alleviate the regional imbalance in available heart surgery services and an overall improvement in cardiovascular disease treatment in South Korea.

Trends in Percutaneous Coronary Intervention and Coronary Artery Bypass Surgery in Korea.

BACKGROUND: Coronary angioplasty has been replacing coronary artery bypass grafting (CABG) because of the relative advantage in terms of recovery time and noninvasiveness of the procedure. Compared to other Organization for Economic Cooperation and Development (OECD) countries, Korea has experienced a rapid increase in coronary angioplasty volumes. METHODS: We analyzed changes in procedure volumes of CABG and of percutaneous coronary intervention (PCI) from three sources: the OECD Health Data, the National Health Insurance Service (NHIS) surgery statistics, and the National Health Insurance claims data. RESULTS: We found the ratio of procedure volume of PCI to that of CABG per 100,000 population was 19.12 in 2014, which was more than triple the OECD average of 5.92 for the same year. According to data from NHIS statistics, this ratio was an increase from 11.4 to 19.3 between 2006 and 2013. CONCLUSION: We found that Korea has a higher ratio of total procedure volumes of PCI with respect to CABG and also a more rapid increase of volumes of PCI than other countries. Prospective studies are required to determine whether this increase in absolute volumes of PCI is a natural response to a real medical need or representative of medical overuse.

Pure ground-glass opacity on chest computed tomography: predictive factors for invasive adenocarcinoma.

BACKGROUND: Pure ground-glass opacity (GGO) on computed tomography (CT) is considered a diagnostic feature of noninvasive lung adenocarcinoma. However, pure GGO can sometimes be associated with invasive adenocarcinoma (IA). The purpose of this study was to determine the predictive factors for IA when pure GGO is present. METHODS: Between 2011 and 2014, 83 patients with persistent pure GGO on chest CT underwent surgical treatment for lung cancer. We compared the clinical, surgical, and pathological characteristics of non-IA with those of IA. RESULTS: A total of 66 patients (79.5%) were diagnosed with non-IA and 17 patients (20.5%) were diagnosed with IA. The mean axial diameter of the GGO lesions in IA was larger than that in non-IA (1.9 vs. 1.2 cm; P<0.001). The incidence of pleural retraction was higher in IA than in non-IA (76.5% vs. 15.2%; P<0.001). Multivariate logistic regression analysis identified GGO lesion size and the presence of pleural retraction as significant predictive factors for IA. CONCLUSIONS: Both preoperative GGO lesion size on CT and the computed-tomography or operative finding of pleural retraction are predictive factors for IA. In patients with these findings, curative lobectomy is preferable to limited resection.