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Biomedical subjects

W C Roberts

Publications and source records attributed to W C Roberts.

At least 541 records · Page 30Linked to original sources
PubMed1979

Infection of glutaraldehyde-preserved porcine valve heterografts.

Gross, histologic and ultrastructural changes associated with bacterial infection are described in four porcine valve heterografts that had been in place in patients for 6 days to 28 months. In one patient, culture of the aortic tissue tag included in the heterograft container grew Mycobacterium chelonei; however, examination of the heterograft, recovered at necropsy 6 days after implantation, revealed small colonies of bacteria that differed morphologically from mycobacteria. A second heterograft was the site of staphylococcal infection associated with extensive destruction of collagen in the leaflets. Similar destruction was observed in a third heterograft, which was found to have organisms on ultrastructural study even though bacterial cultures of the valve were negative. The fourth heterograft, from a patient who died of coronary embolism secondary to dislodgment of vegetative material, contained structures resembling lysed bacteria. Observations in these 4 patients and review of published reports of infection involving 43 other patients with porcine valve heterografts indicates that infection in these valves: (1) develops in the fibrin layer that covers the cusps, (2) can involve the collagen in the leaflets, and (3) is uncommonly (three patients) associated with valve ring abscesses.

Adult↗
PubMed1979

Sucking action of the left ventricle: demonstration of a physiologic principle by a gunshot wound penetrating only the right side of the heart.

This report describes a man who died after a gunshot wound that entered the right atrium and exited from the right ventricle without entering the cardiac septa or the left side of the heart. At necropsy, the left atrial appendage was found to be inverted and invaginated into the mitral orifice. The invagination of the left atrial appendage is viewed as anatomic evidence that a negative left ventricular pressure was created as the left ventricular volume rapidly decreased as a result of right-sided cardiac exsanguination. Previously reported experiments in animals demonstrating the sucking (negative pressure) action of the left ventricle during ventricular diastole are summarized. The prerequisite for creation of a negative pressure in the ventricles during diastole is an extreme diminution in left ventricular volume, in this case as a result of right-sided cardiac bleeding. Only a vacuum effect of the left ventricle during diastole can explain the inversion and invagination of the left atrial appendage in this patient.

Adult↗
PubMed1979

Quantitation of coronary arterial narrowing at necropsy in sudden coronary death: analysis of 31 patients and comparison with 25 control subjects.

A quantitative analysis of the degree and extent of coronary arterial narrowing by atherosclerotic plaques in the entire lengths of each of the four major coronary arteries in a group of patients dying suddenly from coronary heart disease ("sudden coronary death") is described at necropsy. Cross sections were examined histologically in a total of 1,564 five mm long segments of the left main, left anterior descending left circumflex and right coronary arteries in 31 patients with sudden coronary death, and the observations were compared with those from examination of 1,100 five mm segments of the major epicardial coronary arteries in 25 control subjects. An average of 25 cm (50 five mm segments) of coronary artery were examined from each patient and an average of 22 cm (44 five mm segments) from each control subject. Of the 1,564 five mm segments examined in the 31 study patients, 557 (36 percent) were 76 to 100 percent narrowed in cross-sectional area by atherosclerotic plaques (control subjects 3 percent), 536 (34 percent) were 51 to 75 percent narrowed (control subjects 22 percent), 360 (23 percent) were 26 to 50 percent narrowed (control subjects 42 percent) and only 111 segments (7 percent) had 25 percent or less narrowing (control subjects 33 percent). The amount of severe (greater than 75 percent) narrowing of the right, left anterior descending and left circumflex coronary arteries was similar. Additionally, the amount of severe (greater than 75 percent) narrowing in the distal one half of the right, left anterior descending and left circumflex coronary arteries was similar to that in the proximal halves of these three arteries. The number of 5 mm coronary arterial segments narrowed 76 to 100 percent in cross-sectional area in the 31 study patients was not affected by the patient's age of death, sex, presence or absence of previous angina pectoris or myocardial infarction or the weight of the heart.

Adult↗
PubMed1979

Thrombocytosis, coronary thrombosis and acute myocardial infarction.

Clinical and morphologic findings are described in a 22 year old man with prolonged thromboyctosis, and coronary and splenic arterial thrombi causing myocardial and splenic infarcts. The absence of preexistent extensive coronary atherosclerosis, the presence of thrombus in more than one epicardial artery and in multiple intramural coronary arteries, the presence of arterial thrombosis in a noncoronary artery (splenic) and the absence of another apparent cause of the arterial thromboses are evidences that the intraarterial clotting in this patient was related to the severe thrombocytosis. A reveiw of the reported cases of vascular occlusion associated with thrombocytosis indicates that thrombi have infrequently been confirmed as the mechanism of the vascular occlusion. Although the frequency of vascular thrombi in patients with thrombocytosis has not been established, it is clear that vascular thrombosis can be a consequence of thrombocytosis and, as demonstrated by the present patient, that the coronary artery may be the site of the vascular occlusion, a heretofore unconfirmed event.

Adult↗
PubMed1979

Nongenetically transmitted disproportionate ventricular septal thickening associated with left ventricular outflow obstruction.

Clinical, haemodynamic, and morphological features are described in 2 patients with disproportionate ventricular septal thickening, left ventricular outflow obstruction with systolic anterior motion of the anterior mitral leaflet, and either acquired or congenital heart disease. The disproportionate septal thickening in these patients appeared to be secondary to their underlying cardiac disease rather than a manifestation of genetically transmitted hypertrophic cardiomyopathy. One patient with combined aortic and mitral stenosis had severe systolic anterior motion of the anterior mitral leaflet and a residual large systolic pressure gradient between left ventricle and systemic artery after aortic valve replacement. In this patient the systolic anterior motion was evident in the presence of mitral valve stenosis. The other patient with mild aortic stenosis and a previously repaired coarctation of the aorta also had mild systolic anterior motion and a small subaortic systolic pressure gradient. Hence, these 2 patients demonstrate that disproportionate septal thickening secondary to acquired or congenital heart disease may be associated with left ventricular outflow obstruction and systolic anterior motion of the anterior mitral leaflet.

Adolescent↗
PubMed1979

Syndrome of valvular pulmonary stenosis and valvular aortic stenosis with atrial septal defect.

Clinical and morphological findings are described in 2 adults with combined valvular pulmonary and aortic stenosis with atrial septal defect, an extremely rare combination of lesions. The direction of the shunt via the atrial septal defect in this combination appears to be dependent on the relative degree of outflow obstruction on the right side compared with the left side of the heart. In 1 patient the degree of obstruction at the pulmonary valve was nearly three times that at the aortic valve and, therefore, the shunt was right to left and the patient was severely cyanotic. In the other patient, the degree of obstruction at the pulmonary valve was slightly less than that at the aortic valve and, therefore, the shunt was entirely left to right and the patient was acyanotic. Diagnosis of an associated obstructive lesion on the left side of the heart in a patient with an obstructive lesion on the right side of the heart is essential because operative relief of the right-sided obstruction without relief of the left-sided obstruction may lead to rapid, fatal pulmonary congestion.

Adult↗
PubMed1979

Morphologic-physiologic correlates of the severity of fibrosis and degree of cellularity in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive disease of lung parenchyma characterized by a chronic inflammatory cellular infiltration and varying degrees of interstitial fibrosis. Current data indicate that the severity of fibrosis and the degree of cellularity determine, in part, the prognosis of IPF and the response to therapy. Whereas lung biopsy gives the best assessement of fibrosis and cellularity, physiologic studies are used to stage and monitor the disease process. To determine which physiologic studies correlate best with severity of fibrosis and degree of cellularity, these parameters were graded in lung biopsies of 23 patients with IPF and compared with a variety of physiologic studies. Although vital capacity, total lung capacity, and diffusing capacity are commonly used as objective monitors of the disease process, none of these parameters correlated with either the severity of fibrosis or the degree of cellularity in biopsy specimens. In contrast, almost all parameters of lung distensibility correlated with the morphologic assessment of degree of fibrosis; compliance had the best correlation. Parameters of distensibility, however, correlated poorly with the degree of cellularity. In comparison, gas exchange during exercise correlated with both morphologic parameters; the exercise-induced changes in arterial oxygen pressure per liter of oxygen consumed had a high correlation with the degree of fibrosis (r = 0.89; P less than 0.001) and correlated to a lesser extent with the degree of cellularity (r = 0.56; P = 0.009). In contrast, neither the resting arterial oxygen tension nor the arterial oxygen tension at maximal exercise correlated with the morphologic assessment of degree of fibrosis or the degree of cellularity. These morphologic-physiologic comparisons suggest that (a) lung volumes and diffusing capacity are poor monitors of both the degree of fibrosis and the degree of cellularity; (b) the fibrotic process contributes, at least in part, to parameters of lung distensibility, and both fibrosis and cellularity contribute to gas exchange alterations during exercise; and (c) parameters of lung distensibility and exercise-induced gas exchange alterations may be useful in staging the severity of disease in IPF.

Adult↗
PubMed1979

Calcific pulmonic stenosis in adulthood: treatment by valve replacement (porcine xenograft) with postoperative hemodynamic evaluation.

Clinical and morphologic features are described in a 56-year-old man in whom severe, isolated pulmonic valve stenosis was treated by valve replacement with a porcine prosthesis. The calcific deposits were located on the ventricular aspect of the pulmonic valve, opposite the location (arterial aspect) of calcific deposits on stenotic aortic valves, and calcific deposits also were present in the tricuspid valve anulus.

Animals↗
PubMed1979

Coronary artery narrowing in coronary heart disease: comparison of cineangiographic and necropsy findings.

Of 10 patients with fatal coronary heart disease undergoing coronary angiography 0 to 69 d (average, 21) before necropsy, the amount of narrowing in 61 coronary arteries observed angiographically (diameter reduction) during life by three angiographers was compared with that observed histologically (cross-sectional area) at necropsy. No overestimations of the degree of narrowing were made angiographically. Of 11 coronary arteries or their subdivisions narrowed 0 to 50% in cross-sectional area histologically, none were underestimated angiographically; of eight narrowed 51% to 75% histologically, seven had been underestimated, and of 42 narrowed 76% to 100% histologically, 17 were underestimated angiographically. The coronary atherosclerotic plaquing was diffuse (greater than 25% cross-sectional area narrowing) in 90% of 467 five-millimetre segments of coronary artery examined (24 cm per patient), and this diffuseness of the atherosclerotic process seems to be the major reason for angiographic underestimation of coronary narrowings.

Adult↗
PubMed1979

Selective arterialization of the coronary venous system. Encouraging long-term flow evaluation utilizing radioactive microspheres.

The long-term effectiveness of a retrograde coronary venous bypass graft (CVBG) to an ischemic left ventricle was evaluated in 18 dogs. A saphenous vein was interposed between the aorta and left anterior descending (LAD) vein. The LAD vein was ligated cephalad to the CVBG to prevent an arteriovenous fistula. The LAD artery was ligated at its origin to create anterior wall ischemia. Operative graft flow averaged 53 ml. per minute. The 14 surviving dogs were catheterized 3 to 5 months later. Ten of the 14 CVBG's were patent angiographically. The chests were opened and graft flow now averaged 50 ml. per minute. 141Ce microspheres were injected into the left atrium to measure myocardial flow to the anterior wall. In the 10 dogs with patent grafts, transmural flow was 39 +/- 1 (S.E.M.) ml. per 100 Gm. of tissue per minute. The endocardial/epicardial flow ratio was 1.4/1, indicating that retrograde venous perfusion effectively delivered blood to the subendocardium. After ligation of the CVBG, microsphere measured flow dropped to 15 +/- 1 ml. per 100 Gm. per minute. In 15 control dogs, anterior wall flow was 100 +/- 3 ml. per 100 Gm. per minute, decreasing to 13 +/- 2 ml. 45 minutes after ligation of the LAD artery and vein. None of the eight control dogs with simple ligation of the LAD artery and vein survived more than 5 days. Histologic examination of the anterior wall of the left ventricle, the area served by the CVBG's for 3 to 5 months, disclosed no evidence of venous sclerosis or thrombosis and no evidence of interstitial edema or hemorrhage. Thus a CVBG permitted long-term survival in an otherwise nonviable anatomic preparation. Moreover, restoration of flow with a CVBG was effective because it perfused all layers of the myocardium, especially the subendocardium--the crucial layer of myocardial muscle.

Animals↗