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Biomedical subjects

William Clifford Roberts

Publications and source records attributed to William Clifford Roberts.

At least 19 recordsLinked to original sources
PubMed2006

Relation of weights of intraaneurysmal thrombi to maximal right-to-left diameters of abdominal aortic aneurysms.

We determined the weight of operatively excised thrombi within abdominal aortic aneurysms (AAAs) in 42 patients aged 52 to 92 years (mean 73 +/- 9). The thrombi in the 32 men ranged in weight from 12 to 586 g (mean 162 +/- 135) and in the 10 women, from 12 to 351 g (mean 94 +/- 102). The maximal right-to-left diameter of the AAA by computed tomography immediately preoperatively in the 32 men ranged from 5.0 to 11.0 cm (mean 7.6 +/- 1.7), and in the 10 women from 4.0 to 10.5 cm (mean 6.7 +/- 1.9). The relation of the weight of the intraaneurysmal thrombus to the maximal right-to-left diameter of the AAA preoperatively was highly significant in both men (r = 0.72, p <0.001) and women (r = 0.88, p <0.001). In conclusion, the intraaneurysmal thrombi consisted virtually entirely of fibrin, indicating no evidence of organization.

Aged↗
PubMed2006

Aortic valve replacement for aortic stenosis in nonagenarians.

We reviewed certain clinical and morphologic findings in 9 patients who had aortic valve replacement (AVR) for aortic stenosis (AS) when >or=90 years of age. All had AVR from February 2000 to April 2006. The aortic valve areas ranged from 0.41 to 1.00 cm2, and the transvalvular peak systolic gradients ranged from 20 to 110 mm Hg. The left ventricular ejection fractions were >or=50% in 6 of the 9 patients. The aortic valve was congenitally bicuspid in 3 patients, and the operatively excised valves in them weighed 4.20, 5.73, and 9.75 g, respectively (mean 6.56). The other 6 patients had 3-cuspid valves without commissural fusion, and the operatively excised valves in them weighed 0.43, 0.94, 1.08, 1.51, 1.98, and 4.43 g, respectively (median 1.30, mean 1.73). Coronary artery bypass grafting (CABG) was performed at the time of AVR in 8 of the patients. One patient died a day postoperatively and 2 others died 874 and 1,011 days, respectively, after operation. Two were in skilled nursing units postoperatively for several weeks. In conclusion, AS can be severe in nonagenarians and may be superimposed on a congenitally bicuspid aortic valve.

Aged, 80 and over↗
PubMed2006

Causes of pure aortic regurgitation in patients having isolated aortic valve replacement at a single US tertiary hospital (1993 to 2005).

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."

Adult↗
PubMed2006

Frequency of atrial fibrillation in patients having mitral valve repair or replacement for pure mitral regurgitation secondary to mitral valve prolapse.

Relatively little attention has been paid to the frequency of atrial fibrillation (AF) in patients with mitral regurgitation (MR) secondary to mitral valve prolapse (MVP). We reviewed clinical, electrocardiographic, echocardiographic, hemodynamic, and angiographic findings in 246 patients aged 21 to 84 years (mean 61) (66% men) who had mitral valve repair or replacement for MR secondary to MVP. Immediately before the mitral operation by electrocardiogram, only 37 patients (15%) had AF and the other 209 patients were in sinus rhythm. Of the latter, 32 had had a history of AF that had reverted to sinus rhythm spontaneously or with antiarrhythmic therapy. Thus, a total of 69 patients (28%) had AF at some time. In conclusion, the frequency of AF in patients with MR secondary to MVP and sick enough to warrant a mitral valve operation have a relatively low frequency of AF (persistent in 15%, paroxysmal in another 13%), percentages considerably lower than that seen in patients with mitral stenosis just before a mitral commissurotomy or replacement.

Adult↗
PubMed2006

Comparison of findings in patients with versus without atrial fibrillation just before isolated mitral valve replacement for rheumatic mitral stenosis (with or without associated mitral regurgitation).

Among 104 patients with mitral stenosis (MS) severe enough or symptomatic enough to warrant mitral valve replacement (MVR), 47 (45%) had atrial fibrillation (AF) and 57 (55%) had sinus rhythm just before the MVR. Of the latter 57 patients, 21 (37%) had had previous episodes compatible with AF. If these 21 patients were included with the 47 patients with electrocardiographic documentation of AF just before MVR, a total of 68 (65%) would have had > or =1 presumed episodes of AF before MVR. The 13 patients with previous mitral commissurotomy had a frequency of AF similar to that of the 91 whose first operation was MVR. Compared with the patients with sinus rhythm just before MVR, those with AF had more heart failure (functional class III or IV preoperatively, 79% vs 62%), larger left atria (6.0 vs 5.2 cm), larger left ventricles in peak systole (4.0 vs 2.6 cm), and more had 2 or 3 coronary arteries narrowed >50% in diameter (23% vs 10%).

Adult↗
PubMed2005

Comparison of valve structure, valve weight, and severity of the valve obstruction in 1849 patients having isolated aortic valve replacement for aortic valve stenosis (with or without associated aortic regurgitation) studied at 3 different medical centers in 2 different time periods.

BACKGROUND: Aortic valve replacement (AVR) for patients with aortic stenosis (AS) has now been available for 45 years. During this period, indications for the procedure have changed. METHODS AND RESULTS: Operatively excised stenotic aortic valves (with or without associated aortic regurgitation and without associated mitral valve disease) from 3 different medical centers (National Institutes of Health, Georgetown University Medical Center, and Baylor University Medical Center) were examined during 2 different time periods by the same physician to compare aortic valve structure, valve weight, age at operation, preoperative transvalvular peak pressure gradient, calculated aortic valve area, and whether simultaneous coronary artery bypass grafting (CABG) was performed. Compared with the first 3 decades (1961-1990) of AVR, patients having this operation during the fourth and fifth decades (1991-2004) had a lower frequency of congenitally malformed aortic valves, a higher frequency of tricuspid aortic valves, an older age, valves of lighter weight and lower transvalvular peak pressure gradients, and more often simultaneous CABG. CONCLUSIONS: Although patients having isolated AVR for AS in the present and last decade were older than in the first 3 decades of valve replacement surgery, congenitally malformed aortic valves continue to be more common than tricuspid aortic valves, but the degree of AS and therefore, valve weight was significantly lower than in the earlier decades.

Adult↗