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Dive into the research topics where Jong Mi Ko is active.

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Featured researches published by Jong Mi Ko.


Circulation | 2011

Comparison of the Structure of the Aortic Valve and Ascending Aorta in Adults Having Aortic Valve Replacement for Aortic Stenosis Versus for Pure Aortic Regurgitation and Resection of the Ascending Aorta for Aneurysm

William C. Roberts; Travis James Vowels; Jong Mi Ko; Giovanni Filardo; Robert F. Hebeler; Albert Carl Henry; Gregory John Matter; Baron L. Hamman

Background— There is debate concerning whether an aneurysmal ascending aorta should be replaced when associated with a dysfunctioning aortic valve that is to be replaced. To examine this issue, we divided the patients by type of aortic valve dysfunction—either aortic stenosis (AS) or pure aortic regurgitation (AR)—something not previously undertaken. Methods and Results— Of 122 patients with ascending aortic aneurysm (unassociated with aortitis or acute dissection), the aortic valve was congenitally malformed (unicuspid or bicuspid) in 58 (98%) of the 59 AS patients, and in 38 (60%) of the 63 pure AR patients. Ascending aortic medial elastic fiber loss (EFL) (graded 0 to 4+) was zero or 1+ in 53 (90%) of the AS patients, in 20 (53%) of the 38 AR patients with bicuspid valves, and in all 12 AR patients with tricuspid valves unassociated with the Marfan syndrome. An unadjusted analysis showed that, among the 96 patients with congenitally malformed valves, the 38 AR patients had a significantly higher likelihood of 2+ to 4+ EFL than the 58 AS patients (crude odds ratio: 8.78; 95% confidence interval: 2.95, 28.13). Conclusions— These data strongly suggest that the type of aortic valve dysfunction—AS versus pure AR—is very helpful in predicting loss of aortic medial elastic fibers in patients with ascending aortic aneurysms and aortic valve disease.


Circulation | 2006

Causes of Pure Aortic Regurgitation in Patients Having Isolated Aortic Valve Replacement at a Single US Tertiary Hospital (1993 to 2005)

William C. Roberts; Jong Mi Ko; Timothy Richard Moore; William Hampton Jones

Background— The causes of aortic regurgitation (AR) severe enough to warrant aortic valve replacement (AVR) have received little attention in the last 20 years. Methods and Results— We analyzed the causes of pure AR in 268 patients >20 years of age having isolated AVR at Baylor University Medical Center from 1993 to 2005 that was unassociated with mitral stenosis, mitral valve replacement, or a previous operation involving a cardiac valve or ascending aorta. In 122 patients (46%), the AR resulted from a problem with the aortic valve: congenital malformation unassociated with infective endocarditis, 66 patients (54%); infective endocarditis, 46 patients (38%; 15 with bicuspid valves); probable rheumatic heart disease, 8 patients (6%); and miscellaneous, 2 patients (2%). In the other 146 patients (54%), the AR was the consequence of a condition affecting the ascending aorta: dissection, 28 patients (19%); the Marfan syndrome or its forme fruste variety, 15 patients (10%); aortitis, 12 patients (8%), and in the remaining 91 patients (62%), the cause of the AR was not determined. This latter group was the oldest (mean age 66 years), 83 (91%) had hypertension, 26 (29%) had small calcific deposits in the valve cusps, and 46 (51%) had simultaneous coronary artery bypass grafting. Conclusions— The causes of pure AR severe enough to warrant isolated AVR are diverse. The most common category in this study was “cause unclear.”


American Journal of Cardiology | 2009

Natural History of Syphilitic Aortitis

William C. Roberts; Jong Mi Ko; Travis James Vowels

No large studies of cardiovascular syphilis at necropsy have been reported since 1964. We examined at necropsy 90 patients who had characteristic morphologic findings of syphilitic aortitis. None had ever undergone cardiovascular surgery. With the exception of 2 cases seen more recently, the hearts and aortas of the 90 patients were examined and categorized by one of us (W.C.R.) from 1966 to 1990. All 90 had extensive involvement of the tubular portion of the ascending aorta by the syphilitic process, which spared the sinuses of Valsalva in all but 4 patients. The aortic arch was also involved in 49 (91%) of 54 patients and the descending thoracic aorta in 47 (90%) of 52 patients. Syphilis was the cause of death in 23 (26%) of the 90 patients. It was secondary to rupture of the ascending or descending thoracic aorta in 12, severe aortic regurgitation leading to heart failure in 10, and severe narrowing of the aortic ostium of the right coronary artery in 1 patient. Of the 40 patients who had undergone serologic testing for syphilis, 28 (70%) had a positive (reactive) finding. Those patients with a negative or nonreactive test or who did not undergo a serologic test for syphilis had morphologic and histologic findings in the aorta at necropsy similar to the findings of those patients who had had a positive serologic test for syphilis. In conclusion, cardiovascular syphilis has not disappeared. In patients with dilated ascending aortas, with or without aortic regurgitation, a serologic test for syphilis is recommended. If the findings are positive or if characteristic morphologic features of cardiovascular syphilis are suspected, irrespective of the results of the serologic tests, antibiotic therapy appears desirable.


American Journal of Cardiology | 2012

Frequency of Congenitally Bicuspid Aortic Valves in Patients ≥80 Years of Age Undergoing Aortic Valve Replacement for Aortic Stenosis (With or Without Aortic Regurgitation) and Implications for Transcatheter Aortic Valve Implantation

William C. Roberts; Kaitlin Georgeanne Janning; Jong Mi Ko; Giovanni Filardo; Gregory John Matter

The purpose of the present report was to determine the frequency of a congenitally bicuspid aortic valve in patients ≥80 years of age old with aortic stenosis (AS) severe enough to warrant aortic valve replacement. Transcatheter aortic valve implantation (TAVI) has traditionally been reserved for patients ≥80 years of age with severe AS involving a 3-cuspid aortic valve. Traditionally, AS involving a 2-cuspid aortic valve has been a contraindication to TAVI. We examined operatively excised stenotic aortic valves in 364 patients aged ≥80 years to determine the frequency of an underlying congenitally bicuspid aortic valve. Of the 347 octogenarians and 17 nonagenarians, 78 (22%) and 3 (18%) had stenotic congenitally bicuspid aortic valves, respectively. In conclusion, because the results of TAVI are less favorable in patients with stenotic congenitally bicuspid valves than in patients with stenotic tricuspid aortic valves, proper identification of the underlying aortic valve structure is important when considering TAVI as a therapeutic procedure for AS in older patients.


American Journal of Cardiology | 2007

Valve Structure and Survival in Quadragenarians Having Aortic Valve Replacement for Aortic Stenosis (±Aortic Regurgitation) With Versus Without Coronary Artery Bypass Grafting at a Single US Medical Center (1993 to 2005)

William C. Roberts; Jong Mi Ko; Giovanni Filardo; Benjamin L. Kitchens; Albert Carl Henry; Robert F. Hebeler; Edson H Cheung; Gregory John Matter; Baron L. Hamman

The purpose of this study was to determine the effect of simultaneous coronary artery bypass grafting (CABG) and the influence of valve structure on both early and late survival in quadragenarians having aortic valve replacement (AVR) for aortic stenosis (AS) (with or without aortic regurgitation). We analyzed survival and valve structure in 48 adults (12 women), aged 40 to 49 years, having AVR for AS from 1993 through 2005 at Baylor University Medical Center, including 7 (15%) with and 41 (85%) without simultaneous CABG. Of the 48 quadragenarians, none died within 60 days of operation. Assessment of the relation between long-term survival and gender, aortic valve structure, preoperative severity of the AS, and concomitant CABG was not possible due to the low mortality. Four patients (9%) died >60 days after AVR: at 1.8, 6.3, 7.1, and 9.9 years, respectively. The aortic valve was congenitally unicuspid in 15 patients (31%), congenitally bicuspid in 32 (67%), and 3-cuspid in 1 (2%). In conclusion, of the 48 quadragenarians having AVR for AS, 47 (98%) had a congenitally malformed aortic valve, 60-day mortality was zero, and late mortality was low (8%).


American Journal of Cardiology | 2011

Effect Of Body Mass Index On Survival In Patients Having Aortic Valve Replacement For Aortic Stenosis With Or Without Concomitant Coronary Artery Bypass Grafting

William C. Roberts; Carey Camille Roberts; Travis James Vowels; Jong Mi Ko; Giovanni Filardo; Baron L. Hamman; Gregory John Matter; Albert Carl Henry; Robert F. Hebeler

The purpose of this report is to describe the effect of body mass index (BMI) on 30-day and late outcome in patients having aortic valve replacement (AVR) for aortic stenosis (AS) with or without concomitant coronary artery bypass grafting. From January 2002 through June 2010 (8.5 years), 1,040 operatively excised stenotic aortic valves were submitted to the cardiovascular laboratory at Baylor University Medical Center at Dallas. Of the 1,040 cases 175 were eliminated because they had a previous cardiac operation. The present study included 865 adults whose AVR for AS was their first cardiac operation. Propensity-adjusted analysis showed that 30-day and late mortality were strongly and significantly associated with BMI. Decreased risk of 30-day and long-term mortality was observed for patients with BMI in the low 30s compared to patients with BMI in the mid 20s or >40 kg/m(2). In conclusion, the findings in this study indicate a strong and significant adjusted association between BMI and 30-day and long-term mortality in patients having AVR for AS with or without concomitant coronary artery bypass grafting. Better survival was observed in patients with BMIs in the low 30s compared to patients with BMIs in the mid 20s and >40 kg/m(2).


American Journal of Cardiology | 2011

Accuracy of Two-Dimensional Echocardiography in Determining Aortic Valve Structure in Patients >50 Years of Age Having Aortic Valve Replacement for Aortic Stenosis

Ramy F. Ayad; Paul A. Grayburn; Jong Mi Ko; Giovanni Filardo; William C. Roberts

We sought to measure the accuracy of 2-dimensional transthoracic echocardiography in determining aortic valve structure in patients with aortic stenosis (AS) undergoing aortic valve replacement (AVR). Few studies have compared aortic valve structure determined by echocardiogram to that determined by examination of the operatively excised stenotic aortic valve. Two-dimensional echocardiograms were reviewed and interpreted by an expert echocardiographer in blinded fashion in 100 patients >50 years of age (mean 70) who had undergone AVR for isolated AS ± aortic regurgitation and the aortic valve structure (unicuspid, bicuspid, tricuspid) was compared to that from examination of the operatively excised stenotic valve. After excluding 14 cases in which echocardiograms were uninterpretable because of heavy calcium and/or poor image quality, congenitally malformed valves were present in 44 patients (51%) and tricuspid valves in 42 of the 86 patients (49%). Ten of the 14 patients (71%) with uninterpretable echocardiograms had congenitally malformed valves. Valve structure by echocardiogram was concordant with morphologic interpretation in 57 of 86 patients (66% accuracy, kappa = 0.33). Accuracy trended toward improvement as degree of AS decreased. In patients with valve areas similar to those enrolled in the recent transcatheter aortic valve implantation trial (PARTNER; 0.7 ± 0.2 cm(2)), aortic valve structure was accurately determined by echocardiography in 21 of 35 patients (60%). In conclusion, aortic valve structure was interpretable by transthoracic echocardiogram in 86 of 100 patients and accurate in 57 of these 86 patients (66%).


Medicine | 2012

Natural history of adults with congenitally malformed aortic valves (unicuspid or bicuspid).

William C. Roberts; Travis James Vowels; Jong Mi Ko

AbstractAppreciation of the frequency of the congenitally malformed aortic valve has come about during the last 50 years, a period during which aortic valve replacement became a predictably successful operation. Study of patients at necropsy with either a congenitally unicuspid (1 true commissure) or bicuspid (2 true commissures) valve in whom no aortic valve operation has been performed has not been conducted during these 50 years, to our knowledge. We studied 218 patients at necropsy with congenitally malformed aortic valves: 28 (13%) had a unicuspid valve and 190 (87%), a bicuspid valve. Their ages at death ranged from 21 to 89 years (mean, 55 yr), and 80% were men. Of the 218 adults, the aortic valve functioned normally during life in 54 (25%) and abnormally in 164 (75%): aortic stenosis in 142 (65%), pure aortic regurgitation without superimposed infective endocarditis (IE) in 2 (1%), and IE superimposed on a previously normally functioning aortic valve in 20 (9%). IE occurred in a total of 31 (14%) of the 218 patients: involving a previously normally functioning valve in 20 (65%) and a previously stenotic valve in 11 (35%). Of the 218 patients, at least 141 (65%) died as a consequence of aortic valve disease (124 patients) or ascending aortic tears with or without dissection (17 patients). An estimated 1% of the population, maybe higher in men, has a congenitally malformed aortic valve. Data from this study suggest that about 75% of them will develop a major complication. Conversely, and encouragingly, about 25% will go through life without a complication.


The Cardiology | 2007

Clinical and Morphologic Features of the Congenitally Unicuspid Acommissural Stenotic and Regurgitant Aortic Valve

William C. Roberts; Jong Mi Ko

Five adults, aged 30–75 years, are described with stenotic and regurgitant unicuspid acommissural aortic valves. Because none of these patients had clinical, echocardiographic or hemodynamic evidence of mitral valve disease, a case is made that these valves were congenitally malformed and not the result of an acquired condition.


American Journal of Cardiology | 2014

Morphologic features of cardiac sarcoidosis in native hearts of patients having cardiac transplantation.

William C. Roberts; Monica S. Chung; Jong Mi Ko; John E. Capehart; Shelley A. Hall

Described herein are 10 patients who underwent cardiac transplantation (CT) for severe chronic systolic heart failure resulting from cardiac sarcoidosis. None had the diagnosis of sarcoidosis established before CT except for the 3 patients who earlier had had a portion of left ventricular wall excised for insertion of a left ventricular assist device and non-caseating granulomas were present in the removed myocardium. Although none of the 10 patients had significant narrowing of any of the epicardial coronary arteries, all had focal scarring of the walls of the left and right ventricles and ventricular septum and all had dilated ventricular cavities. The patients with the most ventricular wall scarring tended to have the fewest sarcoid granulomas in the ventricular walls. Two patients had no sarcoid granulomas in the excised heart although one did have typical sarcoid granulomas in the portion of left ventricular wall excised to insert a left ventricular assist device. Patients with cardiac sarcoidosis severe enough to warrant CT had characteristic cardiac ventricular morphologic findings, and no dysfunction of other non-cardiac organs, making clinical diagnosis of cardiac sarcoidosis rather difficult.

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William C. Roberts

Baylor University Medical Center

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Shelley A. Hall

University of Texas Southwestern Medical Center

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Gregory John Matter

Baylor University Medical Center

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Baron L. Hamman

Baylor University Medical Center

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Robert F. Hebeler

Baylor University Medical Center

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Travis James Vowels

Baylor University Medical Center

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Albert Carl Henry

Baylor University Medical Center

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Joseph M. Guileyardo

Baylor University Medical Center

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Paul A. Grayburn

Baylor University Medical Center

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Carey Camille Roberts

Baylor University Medical Center

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