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Biomedical subjects

G C Morris

Publications and source records attributed to G C Morris.

At least 73 records · Page 4Linked to original sources
PubMed1977

Celiac axis, superior mesenteric artery, and inferior mesenteric artery occlusion: surgical considerations.

Occlusion of the celiac, superior mesenteric, and inferior mesenteric artery has been studied in 46 patients treated by operation. The condition was acute and was caused by embolic obstruction of the superior mesenteric artery in four cardiac patients and detachment of the inferior mesenteric artery in two patients during removal of infrarenal abdominal aortic aneurysms. The condition was chronic and involved two or all three of the vessels in 40 patient. Embolic obstruction caused severe abdominal pain but few physical signs early in the process,, but the picture of an acute abdomen indicating bowel gangrene developed in a few hours. Ischemia from inferior mesenteric detachment was observed at operation. Patients with chronic obstruction had abdominal pain, weight loss, and diarrhea. Patients with embolic obstruction were treated successfully by embolectomy, and patients developing intraoperative sigmoid ischemia were treated by reattachment of inferior mesenteric arteries to aortic graft. Various procedures were employed in patients with chronic multiple obstruction. However, graft bypass using Dacron tubing was preferable because of its simplicity and because the frequently (48%) associated occlusive disease and aneurysm of the distal aorta were treated at the same time. Confining operation to the abdomen significantly reduced the magnitude of operation and eliminated risks in this age group. Of the 46 patients, 91% survived and were relieved of their symptoms despite associated disease. The 5-year survival rate in this group of patients was 62%.

Adult↗
PubMed1977

Patterns of patency of 596 vein grafts up to seven years after aorta-coronary bypass.

The long-term behavior of vein grafts and their effect on the native circulation were studied by examining 596 vein grafts in 343 patients at a mean follow-up of 15.4 months, range zero to 84 months. Serial studies were performed on 27 patients with 38 grafts. The over-all graft patency rate was 84 per cent, and the rate after more than 5 years was 89 per cent. The patency rate in asymptomatic patients was 91 per cent compared with 81 per cent in the remainder. The patency of grafts attached distal to total occlusions was 82 per cent (78/82). The angle of origin of the grafts from the aorta did not appear to influence patency or the severity of intimal proliferative changes. In 76 patients with 126 grafts, pre- and postoperative cineangiograms were compared, and changes in the graft and underlying coronary artery classified as Groups 1 to to 6: Group 1, patent graft, bidirectional flow in the grafted vessel, proximal lesion unchanged; Group 2, patent graft, bidirectional flow, proximal lesion progressed to occlusion locally; Group 3; patent graft, distal flow only, occlusion of lesion and segment between graft and lesion; Group 4, graft occluded, native artery unaltered; Group 5, graft occluded, native artery now occluded at lesion and region of anastomosis; Group 6, new distal lesion. Results were as follows; Group 1, 58 per cent; Group 2, 21.2 per cent; Group 3, 5 per cent, Group 4, 12.5 per cent; Group 5, 2.5 per cent; and Group 6, 0.8 per cent. Native coronary arteries undergoing closure (Group 2) had lesions 95 per cent or greater in 93 per cent of patients. The rate of closure of ungrafted lesions was 2 per cent. We believe these results encourage the continued used of vein bypass grafts.

Coronary Artery Bypass↗
PubMed1976

Vein graft patency and intimal proliferation after aortocoronary bypass: early and long-term angiopathologic correlations.

To determine the clinical significance of intimal proliferation as a cause of aortocoronary bypass vein graft obstruction, 492 vein grafts from 281 patients were studied 0 to 75 months postoperatively. All grafts had been inserted between 1968 and 1975 by one surgeon using one technique. The graft patency rate was 92 percent (55 to 60) in the first month; 91 percent (49 of 54) at 1 to 3 months; 84 percent (37 to 44) at 4 to 6 months; 77 percent (33 of 43) at 7 to 12 months; 81 percent (113 of 140) at 13 to 24 months; 82 percent (59 of 72) at 25 to 36 months; and 84 percent (66 of 79) at 37 to 75 months. Vein graft samples were obtained from 41 patients: In 27 patients with 51 grafts (early group), they were obtained 0 to 30 days (mean 14 days) postoperatively; in 14 patients with 27 grafts (late group) they were obtained 7 to 75 months (mean 34 months) postoperatively. Intimal proliferation was graded 1 to 4 corresponding to an intima/media thickness ratio of 1,2,3 or 4, respectively. In the early group, all 51 vein grafts howed grade 1 to 2 intimal proliferation; 5 of these grafts were occluded, all as a result of recent thrombosis. In the late group, 17 of the 27 grafts were studied histologically. All patent vein grafts showed grade 2 to 3 intimal prolferation. Four vein grafts were occluded but only one as a result of grade 4 intimal proliferation. In 14 patients in the late group, angiograms performed shortly before vein graft samples were obtained revealed 14 patent and 4 occluded vein grafts. Ten of the 14 patent vein grafts showed grade 2 to 3 intimal proliferation but were of uniformly good caliber angiographically (graft/artery ratio more than 1.5).

Adult↗
PubMed1976

Aortocoronary saphenous vein autograft accidentally attached to a coronary vein: follow-up angiography and surgical correction of the resultant arteriovenous fistula.

The fate of aortocoronary saphenous vein bypass graft to the left anterior descending (LAD) coronary vein is reported. The vein graft communicated with the coronary sinus through the proximal LAD vein, producing a functional coronary arteriovenous fistula. The LAD vein was totally occluded distally at follow-up four months after operation. The natural history of congenital fistulas between coronary arteries and the coronary sinus suggested that bacterial endocarditis, pulmonary hypertension, and cardiac failure were all possible future complications in this patient. Operation was performed to revascularize the LAD artery to relieve persistent angina, and to close the fistula. Postoperative angiography showed a patent graft to the LAD artery with complete obliteration of the fistula. The patient is asymptomatic ten months after operation.

Adult↗
PubMed1976

Clinical experience with the Teflo disposable membrane oxygenator.

A simple, inexpensive, highly efficient disposable membrane oxygenator with low priming volume and a microporous membrane recently has become available. Animal and clinical investigations of its use have been most satisfactory, and clinical experience now has been extended to include 285 patients. Its primary advantage has been the ability to control oxygenation and carbon dioxide separately. Disadvantages have included the somewhat increased complexity of the system as compared with bubble oxygenator systems, the necessity of converting pumps for its use, and excessive condensation of water vapor in the gas phase of the oxygenator unless certain precautions are followed.

Adolescent↗
PubMed1976

Left subcostal insertion of the sutureless myocardial electrode.

This report describes the use of a left subcostal extrapleural supradiaphragmatic approach to the heart for myocardial sutureless electrode insertion. Electrode insertion by this approach has consistently produced low electrode thresholds, and the ability to insert electrodes into the left ventricle or septal area of the right ventricle is considered an advantage. This technique has now been used in 52 patients. Postoperative morbidity and complications have been minimal. The procedure appears to be well tolerated in the elderly, poor-risk patient and has been a useful technique for revision of failed pacemaker systems. We believe this procedure reduces the indications for permanent transvenous pacing.

Adult↗
PubMed1976

Growth of rats' kidneys after unilateral uretero-caval anastomosis.

1. The relative significance of reduced excretion of urinary constituents and reduced renal mass, as stimuli to growth of one kidney after the other has been removed, has been investigated. 2. To abolish the excretory function of one kidney without removing it, the right ureter was drained into the vena cava through a compound cannula for 6 weeks. Uretero-caval anastomoses were performed in twenty-four male rats at 10 weeks of age: six survived without evidence of ureteric obstruction (and a further five with minimal obstruction). 3. The rats with anastomoses grew less than six other rats from which the right kidney had been removed or six which had been submitted to a sham operation, and their plasma urea and creatinine concentrations were higher. 4. Relative to body weight, the dry weight of each kidney after uretero-caval anastomosis without obstruction was 18% greater than after sham operation; taking both kidneys together, the total increase was almost as much as in the left kidney alone after right nephrectomy (46%). 5. Histologically and in terms of DNA concentration, the growth of both kidneys after uretero-caval anastomosis was of the same kind as in the left kidney after right nephrectomy. 6. The return of urine from one kidney into the blood provided a powerful stimulus to renal growth in spite of the restraining effect of increased renal mass.

Animals↗