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Team approach for clinical cardiac surgery research
CORRESPONDENCE
Team Approach for Clinical Cardiac Surgery Research To the Editor: Recent advances in computer technology have made it possible to compile data about various characteristics of patient populations, such as surgical procedures performed, postoperative management options, and the clinical outcome of patients. As a result, many academic institutions have placed an increased emphasis on clinical research. To take advantage of advances in the areas of computer technology, biostatistics, and data compilation, researchers must have expertise in these specific branches of science. The importance of the coordinated effort of many professionals is central to achieving quality clinical research in academic surgery, particularly in the field of cardiac surgery. Many factors should be considered when planning data collection and research strategies. These factors include the logistics of data collection, storage, and retrieval, as well as the difficulties associated with complex data analysis, interpretation, and presentation. A comprehensive research plan requires staff with expertise in data collection, data entry, database programming, research design, statistics, and data analysis. Database management has become an efficient means of conducting clinical research; one computer can replace vast filing systems, and electronic data storage can quickly produce multiple reports. Because the task of data collection, analysis, interpretation, presentation, and reporting, when it involves computerized databases, is a complex process, it is important to include experts in research design and statistics as members of the research team. These professionals can help to prevent design flaws that may threaten the validity of the studies. Using the technique of power analysis, they can make critical suggestions on sample size [l], which in many cases may determine whether the findings of the study will achieve statistical significance. A preferred research team comprises specialized staff for data collection, data entry, database management, microcomputer work, mainframe programming, and research designktatistics. The clinical data collector abstracts data from many complex sources (eg, medical records, patient charts). The data entry expert transfers the abstracted data to the computer. The computer programmer provides software programming to facilitate data entry. The microcomputer expert solves database and data entry problems and converts data into an exchangeable form. The mainframe computer expert is responsible for the conversion of data entered in alphanumeric or database form (eg, yedno) to purely numeric or research form (eg, 1, 0), the analysis of these data using a variety of statistical methods, and the storage of data. The statistician and research experts must be involved from the beginning of the research project to ensure that potential problems are identified before data collection. They can identify areas where precise data collection will provide a more accurate estimate of clinical impact. The value of sample size analysis before conducting a research study is paramount, and this determination most often falls in the domain of the statistician. Predetermining the sample size is important because insufficient sample size will result in the inability to demonstrate statistical and thus clinical importance. A reduced sample size is beneficial because it may decrease the time and cost involved in a study. The statistician also determines what type of statistical analysis should be applied to the clinical data. Current research designs usually involve repeated measures and multifactorial occurrences. Therefore, complex research designs may require a sophisticated statistical analysis, thus demonstrating the need for an expert who can solve multifactorial problems. Clinical research in an academic center is helpful for improving 0 1992 by The Society of Thoracic Surgeons
patient care, identifying important surgical risk factors, and reducing operative mortality and morbidity. As a result, researchers are taking an increased interest in the easily obtainable data collected at various hospitals at the regional [2], state [3], and national [4] levels. The ideal cardiac surgery research team is a true collaboration of efforts among cardiac surgeons and various experts in database management. This team approach provides a productive scientific atmosphere and enhances the quality of the research work. Thus, a coordinated cardiac surgery research team may increase the academic productivity of an institution where clinical research is an important priority.
Charles C. Canver, M D Section of Cardiothoracic Surge y Dartmou th Medical School Dartmou th-Hitchcock Medical Center One Medical Center Dr Lebanon, N H 03756 Roger C. Fiedler, PhD Department of S u r g e y
SUNY at Buffalo
100 High St Buffalo, NY 14203
References 1. Cohen J. Statistical power analysis for the behavioral sciences. Hillsdale, NJ: Lawrence Erlbaum Associates, 1988. 2. OConnor GT, Plume SK, Olmstead EM, et al. A regional prospective study of in-hospital mortality associated with coronary artery bypass grafting. JAMA 1991;266:80%9. 3. Hannan EL, Kilburn H Jr, O’Donnell JF, Lukacik G, Shields EP. Adult open heart surgery in New York state: an analysis of risk factors and hospital mortality rates. JAMA 1990;264: 2768-74. 4. Grover FL, Hammermeister KE, Burchfiel C, Cardiac Surgeons of the Department of Veterans Affairs. Initial report of the Veterans Administration preoperative risk assessment study for cardiac surgery. Ann Thorac Surg 1990;50:12-28.
Length of the In Situ Right Gastroepiploic Artery for Coronary Artery Bypass To the Editor: In a recent article, Saito and colleagues [l] described the availability of right gastroepiploic artery (GEA) grafts in terms of length and diameter as examined at the time of operation and angiographically. In a recently published study, we [2] described an anatomical study of the GEA in cadavers to assess the length of this arterial conduit in situ and try to determine the shortest route (antegastric versus retrogastric) to the recipient coronary arteries for its use in coronary revascularization. The length of the conduit was measured from its origin until the point where the internal diameter allowed a 1.5-mm-caliber probe, which is enough to perform an anastomosis. In our study, in all patients the midpoint of all coronary arteries could be reached with an in situ GEA. The length of the harvested GEA conduits varied from 25 to 31 cm (mean, 26.7 2 1.9 cm). The shortest route to the right main coronary artery, the posterior descending artery, and the circumflexbranch was retrogastric and posterior to the left lobe of the liver, whereas to the diagonal branch and the left anterior descending artery the antegastric route was shorter (in 3 patients with hepatomegaly a route posterior to the left lobe of the liver was shorter). However the differences between the antegastric and retrogastric routes were not statistically significant. Ann Thorac Surg 1992;54:124.1-9
0003-4975/92/$5.00
Team Approach for Clinical Cardiac Surgery Research To the Editor: Recent advances in computer technology have made it possible to compile data about various characteristics of patient populations, such as surgical procedures performed, postoperative management options, and the clinical outcome of patients. As a result, many academic institutions have placed an increased emphasis on clinical research. To take advantage of advances in the areas of computer technology, biostatistics, and data compilation, researchers must have expertise in these specific branches of science. The importance of the coordinated effort of many professionals is central to achieving quality clinical research in academic surgery, particularly in the field of cardiac surgery. Many factors should be considered when planning data collection and research strategies. These factors include the logistics of data collection, storage, and retrieval, as well as the difficulties associated with complex data analysis, interpretation, and presentation. A comprehensive research plan requires staff with expertise in data collection, data entry, database programming, research design, statistics, and data analysis. Database management has become an efficient means of conducting clinical research; one computer can replace vast filing systems, and electronic data storage can quickly produce multiple reports. Because the task of data collection, analysis, interpretation, presentation, and reporting, when it involves computerized databases, is a complex process, it is important to include experts in research design and statistics as members of the research team. These professionals can help to prevent design flaws that may threaten the validity of the studies. Using the technique of power analysis, they can make critical suggestions on sample size [l], which in many cases may determine whether the findings of the study will achieve statistical significance. A preferred research team comprises specialized staff for data collection, data entry, database management, microcomputer work, mainframe programming, and research designktatistics. The clinical data collector abstracts data from many complex sources (eg, medical records, patient charts). The data entry expert transfers the abstracted data to the computer. The computer programmer provides software programming to facilitate data entry. The microcomputer expert solves database and data entry problems and converts data into an exchangeable form. The mainframe computer expert is responsible for the conversion of data entered in alphanumeric or database form (eg, yedno) to purely numeric or research form (eg, 1, 0), the analysis of these data using a variety of statistical methods, and the storage of data. The statistician and research experts must be involved from the beginning of the research project to ensure that potential problems are identified before data collection. They can identify areas where precise data collection will provide a more accurate estimate of clinical impact. The value of sample size analysis before conducting a research study is paramount, and this determination most often falls in the domain of the statistician. Predetermining the sample size is important because insufficient sample size will result in the inability to demonstrate statistical and thus clinical importance. A reduced sample size is beneficial because it may decrease the time and cost involved in a study. The statistician also determines what type of statistical analysis should be applied to the clinical data. Current research designs usually involve repeated measures and multifactorial occurrences. Therefore, complex research designs may require a sophisticated statistical analysis, thus demonstrating the need for an expert who can solve multifactorial problems. Clinical research in an academic center is helpful for improving 0 1992 by The Society of Thoracic Surgeons
patient care, identifying important surgical risk factors, and reducing operative mortality and morbidity. As a result, researchers are taking an increased interest in the easily obtainable data collected at various hospitals at the regional [2], state [3], and national [4] levels. The ideal cardiac surgery research team is a true collaboration of efforts among cardiac surgeons and various experts in database management. This team approach provides a productive scientific atmosphere and enhances the quality of the research work. Thus, a coordinated cardiac surgery research team may increase the academic productivity of an institution where clinical research is an important priority.
Charles C. Canver, M D Section of Cardiothoracic Surge y Dartmou th Medical School Dartmou th-Hitchcock Medical Center One Medical Center Dr Lebanon, N H 03756 Roger C. Fiedler, PhD Department of S u r g e y
SUNY at Buffalo
100 High St Buffalo, NY 14203
References 1. Cohen J. Statistical power analysis for the behavioral sciences. Hillsdale, NJ: Lawrence Erlbaum Associates, 1988. 2. OConnor GT, Plume SK, Olmstead EM, et al. A regional prospective study of in-hospital mortality associated with coronary artery bypass grafting. JAMA 1991;266:80%9. 3. Hannan EL, Kilburn H Jr, O’Donnell JF, Lukacik G, Shields EP. Adult open heart surgery in New York state: an analysis of risk factors and hospital mortality rates. JAMA 1990;264: 2768-74. 4. Grover FL, Hammermeister KE, Burchfiel C, Cardiac Surgeons of the Department of Veterans Affairs. Initial report of the Veterans Administration preoperative risk assessment study for cardiac surgery. Ann Thorac Surg 1990;50:12-28.
Length of the In Situ Right Gastroepiploic Artery for Coronary Artery Bypass To the Editor: In a recent article, Saito and colleagues [l] described the availability of right gastroepiploic artery (GEA) grafts in terms of length and diameter as examined at the time of operation and angiographically. In a recently published study, we [2] described an anatomical study of the GEA in cadavers to assess the length of this arterial conduit in situ and try to determine the shortest route (antegastric versus retrogastric) to the recipient coronary arteries for its use in coronary revascularization. The length of the conduit was measured from its origin until the point where the internal diameter allowed a 1.5-mm-caliber probe, which is enough to perform an anastomosis. In our study, in all patients the midpoint of all coronary arteries could be reached with an in situ GEA. The length of the harvested GEA conduits varied from 25 to 31 cm (mean, 26.7 2 1.9 cm). The shortest route to the right main coronary artery, the posterior descending artery, and the circumflexbranch was retrogastric and posterior to the left lobe of the liver, whereas to the diagonal branch and the left anterior descending artery the antegastric route was shorter (in 3 patients with hepatomegaly a route posterior to the left lobe of the liver was shorter). However the differences between the antegastric and retrogastric routes were not statistically significant. Ann Thorac Surg 1992;54:124.1-9
0003-4975/92/$5.00