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Featured researches published by Jong M. Ko.


Circulation | 2005

Frequency by Decades of Unicuspid, Bicuspid, and Tricuspid Aortic Valves in Adults Having Isolated Aortic Valve Replacement for Aortic Stenosis, With or Without Associated Aortic Regurgitation

William C. Roberts; Jong M. Ko

Background—Aortic valve stenosis (with or without aortic regurgitation and without associated mitral stenosis) in adults in the Western world has been considered in recent years to most commonly be the result of degenerative or atherosclerotic disease. Methods and Results—We examined operatively excised, stenotic aortic valves from 932 patients aged 26 to 91 years (mean±SD, 70±12), and none had associated mitral valve replacement or evidence of mitral stenosis: A total of 504 (54%) had congenitally malformed valves (unicuspid in 46 [unicommissural in 42; acommissural in 4] and bicuspid in 458); 417 (45%) had tricuspid valves (either absent or minimal commissural fusion); and 11 (1%) had valves of undetermined type. It is likely that the latter 11 valves also had been congenitally malformed. Of the 584 men, 343 (59%) had either a unicuspid or a bicuspid valve; of the 348 women, 161 (46%) had either a unicuspid or a bicuspid aortic valve. Conclusions—The data from this large study of adults having isolated aortic valve replacement for aortic stenosis (with or without associated aortic regurgitation) and without associated mitral stenosis or mitral valve replacement strongly suggest that an underlying congenitally malformed valve, at least in men, is more common than a tricuspid aortic valve.


Journal of the American College of Cardiology | 2014

Gross and Histological Features of Excised Portions of Posterior Mitral Leaflet in Patients Having Operative Repair of Mitral Valve Prolapse and Comments on the Concept of Missing (= Ruptured) Chordae Tendineae

William C. Roberts; Travis J. Vowels; Jong M. Ko; Robert F. Hebeler

OBJECTIVESnThe aim of the study is to describe gross and histological features of operatively excised portions of mitral valves in patients with mitral valve prolapse (MVP).nnnBACKGROUNDnAlthough numerous articles on MVP (myxomatous or myxoid degeneration, billowing or floppy mitral valve) have appeared, 2 virtually constant histological features have been underemphasized or overlooked: 1) the presence of superimposed fibrous tissue on both surfaces of the leaflets and surrounding many chordae tendineae; and 2) the absence of many chordae tendineae on the ventricular surfaces of the leaflets as the result of their being hidden (i.e., covered up) by the superimposed fibrous tissue.nnnMETHODSnWe examined operatively excised portions of prolapsed posterior mitral leaflets in 37 patients having operative repair.nnnRESULTSnHistological study of elastic-tissue stained sections disclosed that the leaflet thickening was primarily due to the superimposed fibrous tissue. All leaflets had variable increases in the spongiosa element within the leaflet itself with some disruption and/or loss of the fibrosa element and occasionally complete separation of it from the spongiosa element. Both the leaflet and chordae were separated from the superimposed fibrous tissue by their black-staining elastic membranes.nnnCONCLUSIONSnThese findings demonstrate that the posterior leaflet thickening in MVP is mainly due to the superimposed fibrous tissue rather than to an increased volume of the spongiosa element of the leaflet itself. The superimposed fibrous tissue on both leaflet and chordae is likely the result of subsequent abnormal contact of the leaflets and chordae with one another. Chordal rupture (i.e., missing chordae) occurred in all 37 patients, but finding individual ruptured chords was rare.


American Journal of Cardiology | 2013

Natural history of unoperated aortic stenosis during a 50-year period of cardiac valve replacement.

William C. Roberts; Travis J. Vowels; Giovanni Filardo; Jong M. Ko; Raj P. Mathur; Jamshid Shirani

Although a number of publications have described the natural history of patients with aortic stenosis (AS), the definition of natural history varies widely. Those describing a large number of patients with AS without operative therapy with necropsy findings are rare. Two hundred sixty patients >15 years of age with AS were studied at necropsy over a 50-year period by the same investigator. Of the 260 patients, the valve in 37 (14%) was congenitally unicuspid, in 123 (47%), congenitally bicuspid, and in 100 (38%), tricuspid. Aortic valve structure varied with age of death (in years; unicuspid 52 ± 17, bicuspid 63 ± 12, and tricuspid 70 ± 14 years); gender (men/women: unicuspid 95%/5%, bicuspid 78%/22%, and tricuspid 63%/37%), and frequency of calcium in the mitral valve annulus and epicardial coronary arteries. The patients with cardiac-related symptoms compared with those without were more likely to have a congenitally malformed valve (unicuspid 17% vs 12%; bicuspid 51% vs 29%; tricuspid 31% vs 60%; unadjusted p = 0.013), to die from cardiac disease (86% vs 54%; unadjusted p = 0.001), and to have larger hearts (mean cardiac weight 606 ± 138 g vs 523 ± 121 g; unadjusted p = 0.009) and a larger quantity of calcium in the aortic valve cusps. In conclusion, the length of survival in adults with AS is related to valve structure, gender, presence of cardiac-related symptoms, cardiac mass, and quantity of calcium in the aortic valve cusps.


Journal of the American College of Cardiology | 2014

Anomalous cord from the raphe of a congenitally bicuspid aortic valve to the aortic wall producing either acute or chronic aortic regurgitation.

Travis J. Vowels; Gonzalo V. Gonzalez-Stawinski; Jong M. Ko; Gregory D. Trachiotis; Brad J. Roberts; Charles S. Roberts; William C. Roberts

OBJECTIVESnThis report calls attention to an unappreciated cause of both acute and chronic aortic regurgitation (AR).nnnBACKGROUNDnAlthough stenosis develops in most patients with a congenitally bicuspid aortic valve (BAV), in others with this anomaly, pure AR (no element of stenosis) develops, some in the absence of infection or other clear etiology.nnnMETHODSnWe describe 5 men who underwent aortic valve replacement for pure AR associated with a BAV containing an anomalous cord attaching the raphe of the conjoined cusp near its free margin to the wall of the ascending aorta cephalad to the sinotubular junction.nnnRESULTSnThree of these 5 patients had a history of progressive dyspnea, and the anomalous cord, which was intact at operation, appeared to cause chronic AR by preventing proper coaptation of the 2 aortic valve cusps. The other 2 patients heard a pop during physical exertion and immediately became dyspneic, and at operation, the anomalous cord was found to have ruptured. Prolapse of the conjoined aortic valve cusp toward the left ventricular cavity resulted in severe acute AR.nnnCONCLUSIONSnThis variant of the purely regurgitant BAV may cause either chronic AR (when the anomalous cord does not rupture) or acute severe AR (when the cord ruptures).


American Journal of Cardiology | 2015

Electrocardiographic Total 12-Lead QRS Voltage in Patients Having Operative Resection of Syphilitic Aortic Aneurysm

William C. Roberts; Clay M. Barbin; Matthew R. Weissenborn; Jong M. Ko

Electrocardiographic voltage has been used to determine the presence of left ventricular hypertrophy for about 70 years. Varying electrocardiographic criteria have been applied. We have found total 12-lead QRS voltage to be most useful in this regard. We measured total 12-lead QRS voltage in 24 patients in whom an ascending aortic aneurysm was resected and histologic study of its wall was classic of syphilitic aortitis. In these 24 patients total 12-lead QRS voltage ranged from 57 to 161 mm, averaging 120 ± 32 in the 11 men and 106 ± 24 mm in the 13 women. If normal 12-lead QRS voltage in adults is considered to be >175 mm not a single one of the 24 patients had normal voltage. Indeed, most were in the low normal area. Thus, this study provides some evidence via this indirect means that the heart itself is infrequently involved by syphilitic aortitis which produces an ascending aortic aneurysm of sufficient size to warrant resection.


Proceedings (Baylor University. Medical Center) | 2014

Infective endocarditis superimposed on a massively calcified severely stenotic congenitally bicuspid aortic valve

Syed A. Sarmast; Jeffrey M. Schussler; Jong M. Ko; William C. Roberts

We describe a 55-year-old man who presented with a stroke resulting from active infective endocarditis (IE) involving a heavily calcified bicuspid aortic valve. The case highlights the infrequency of IE involving a heavily calcified valve, the inability of the infection to penetrate the calcific deposits, and the ability of the infection to spread to the adjacent soft tissues, leading to ring abscess and its multiple complications.


American Journal of Cardiology | 2013

Necropsy Findings Early After Transcatheter Aortic Valve Implantation for Aortic Stenosis

William C. Roberts; Robert C. Stoler; Paul A. Grayburn; Robert F. Hebeler; Jong M. Ko; David L. Brown; Michael J. Mack; Joseph M. Guileyardo

Although transcatheter aortic valve implantation has been available for 10 years, reports of cardiovascular morphologic studies after the procedure are virtually nonexistent. The investigators describe such findings in 2 patients, both 86 years of age, who died early (hours or several days) after transcatheter aortic valve implantation. Although the prosthesis in each was seated well, and each of the 3 calcified cusps of the native aortic valves was well compressed to the wall of the aorta, thus providing a good bioprosthetic orifice, the ostium of the dominant right coronary artery in each was obliterated by the native right aortic valve cusp. Atherosclerotic plaques in the common iliac artery led to a major complication in 1 patient, who later died of hemorrhagic stroke. The other patient developed fatal cardiac tamponade secondary to perforation of the right ventricular wall by a pacemaker catheter.


Journal of the American College of Cardiology | 2004

Relation of weights of operatively excised stenotic aortic valves to preoperative transvalvular peak systolic pressure gradients and to calculated aortic valve areas

William C. Roberts; Jong M. Ko


/data/revues/00029149/unassign/S0002914915016902/ | 2015

Syphilis as a Cause of Thoracic Aortic Aneurysm

William C. Roberts; Clay M. Barbin; Matthew R. Weissenborn; Jong M. Ko; A.Carl Henry


/data/revues/00029149/unassign/S0002914915016859/ | 2015

Computed Tomographic and Morphologic Features of Syphilis of the Aorta

Clay M. Barbin; Matthew R. Weissenborn; Jong M. Ko; Joseph E. Guileyardo; William C. Roberts

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William C. Roberts

Baylor University Medical Center

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Clay M. Barbin

Baylor University Medical Center

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Matthew R. Weissenborn

Baylor University Medical Center

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Travis J. Vowels

Baylor University Medical Center

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Robert F. Hebeler

Baylor University Medical Center

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A.Carl Henry

Baylor University Medical Center

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Brad J. Roberts

Baylor University Medical Center

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Charles S. Roberts

Brigham and Women's Hospital

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