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Biomedical subjects

A Cragg

Publications and source records attributed to A Cragg.

15 recordsLinked to original sources
PubMed1996

[Endoluminal therapy of infrarenal abdominal aortic aneurysms: a new interventional technique].

PURPOSE: With a series of 31 transluminal stent-graft procedures, we assessed the feasibility and clinical effectiveness of a new stent-graft for the treatment of infrarenal abdominal aortic aneurysms (AAAs). METHODS: We treated the patients (male; mean age 71 years) with straight or bifurcated nitinol stents covered with woven dacron graft material for infrarenal eccentric saccular AAA (n = 4) or AAA involving the bifurcation and the common iliac arteries (n = 27). The 18-F delivery system was advanced via a surgical arteriotomy and the stent-graft was placed under fluoroscopic control. Follow-up period ranged from 8 days to 9 months. RESULTS: The implantation of the stent-grafts was technically successful in 30/31 cases. Procedure-related complications were acute hepatic failure due to gastric bleeding in a patient with liver cirrhosis, graft occlusion due to emboli originating from the left atrium (n = 1), macro-embolisation (n = 3), local haematoma (n = 1) and av-fistula (n = 1) requiring surgery. A post-implantation syndrome with leukocytosis and elevated C-reactive protein was observed in all patients. CONCLUSIONS: Endoluminal repair of infrarenal AAA with use of dacron covered nitinol stent-grafts is feasible, safe and clinically effective. However, careful long-term evaluation is necessary.

Aged↗
PubMed1996

Occlusive and aneurysmal peripheral arterial disease: assessment of a stent-graft system.

PURPOSE: To assess the use of a recently developed stent-graft system for treatment of occlusive lesions and aneurysms in the iliac and femoropopliteal arteries. MATERIALS AND METHODS: The stent-graft consisted of a nitinol stent framework covered by a thin-walled polyester fabric. The device was used in 105 patients with symptomatic peripheral vascular disease. Implant locations were iliac artery (n = 38), femoral artery (n = 62), and popliteal artery (n = 5). RESULTS: Initial technical success was achieved in all patients except one with occlusive disease and one with aneurysmal disease. Residual stenosis after stent-graft implantation was 0.5% +/- 3. Mean ankle-brachial index increased from 0.53 to 0.98. Complications were hematoma (n = 3), pseudoaneurysm (n = 2), puncture site thrombosis (n = 1), early graft thrombosis (n = 8), graft misplacement (n = 1), distal embolization (n = 2), delayed thrombosis (n = 14), pain and fever (n = 27). At the iliac level, primary patency was 97% and secondary patency was 100%. At the femoral level, primary patency was 59% and secondary patency was 81%. CONCLUSION: Endoluminal bypass with a percutaneously delivered stent-graft is feasible. Technical results are good, and the number of complications is few at the iliac level. At the femoropopliteal level, patency is not as good and the number of complications is higher.

Adult↗
PubMed1984

Infantile peliosis hepatis. A case report.

Peliosis in a 13-month-old infant is described. This patient appears to be the youngest reported case. The radiologic diagnosis of peliosis is difficult. The condition may be confused with other more common liver diseases. Peliosis is best assessed angiographically.

Diagnosis, Differential↗
PubMed1984

Nephrotoxicity of contrast media assessed by occlusion arteriography.

The authors describe an experimental model for the study of nephrotoxicity induced by contrast media, based on a standardized injection combined with occlusion of the renal artery so as to expose the kidney to a high concentration of contrast medium for ten minutes. Iopamidol, ioxaglate, and both isosmolar and hyperosmolar saline were well tolerated, but diatrizoate caused marked radiological and pathological changes. This model may be helpful in studies of the mechanisms underlying contrast medium nephrotoxicity and evaluating differences in toxicity between contrast agents.

Animals↗
PubMed1984

Long-term patency of the ductus arteriosus after balloon dilatation: an experimental study.

Balloon dilatation of the ductus arteriosus was carried out in vivo in eight piglets that were 12 to 16 days old. The ductus was functionally closed in all animals before dilatation. Long-term patency for periods of up to 6 months after the procedure was demonstrated in six animals by angiography, Doppler ultrasound examination, and at autopsy. The presence of hemodynamically significant shunts was indicated by clinical development of heart failure, pulmonary infections, and left ventricular hypertrophy. These results confirm the value of this laboratory preparation to create left-to-right shunts at the ductus level.

Angioplasty, Balloon↗
PubMed1984

Role of ischemia in contrast-induced renal damage: an experimental study.

Total and regional cortical blood flow was measured in dogs by the radioactive microsphere technique after renal damage of varying severity had been induced by combining selective injection of diatrizoate, iopamidol, or normal saline with a 10 min occlusion of the renal artery. There was extensive tubular and glomerular damage in the kidneys exposed to diatrizoate, but not in the kidneys exposed to saline. Iopamidol caused intermediate changes. Average cortical blood flow was reduced from baseline levels in all groups 5 min after perfusion was restored. After 1 hr the flow had returned to the baseline level. Analysis of variance did not show a statistically significant difference among the groups. A tendency for redistribution of flow from outer to inner cortical layers was seen, but this was present in all groups. The flow changes detected in this study cannot explain the varying severity of renal damage.

Animals↗
PubMed1984

Percutaneous transluminal angioplasty for treatment of renal artery stenosis in children.

Angioplasty was carried out in four children with hypertension and renal artery stenosis, including one patient with neurofibromatosis and one patient with multiple arterial stenoses. Two patients did not respond. In the patient with neurofibromatosis the stenosis persisted unchanged despite multiple balloon inflations. In one patient hypertension persisted despite successful dilatation, and was probably related to longstanding contralateral kidney disease. Two patients had excellent blood pressure response to dilatation. One of these patients required redilatation of bilateral recurrent stenoses.

Adolescent↗
PubMed1983

Vessel wall arachidonate metabolism after angioplasty: possible mediators of postangioplasty vasospasm.

The mechanism of postangioplasty vasospasm is uncertain. It was postulated that a reduction in vasodilator prostaglandin I2 (PGI2) or prostaglandin E2 (PGE2) or an increase in vasoconstrictor hydroperoxy acids might contribute to spasm of a dilated artery. Twelve mongrel dogs were anesthetized, intubated, and mechanically ventilated. Heart rate and aortic pressures were continuously monitored and arterial blood gases maintained within physiologic limits. A single carotid artery was dilated in each animal (4 atm X 1 minute X 3) using nonexpandable polyethylene balloon catheters with inflated balloon diameters 50 to 100% larger than the internal arterial lumen. The opposite carotid artery served as a control. In 4 animals, aspirin (10 mg/kg, intravenously) was injected 30 minutes before dilation. Sixty minutes after dilation, animals were heparinized and the carotid arteries carefully removed. The in vitro conversion of carbon-14(14C)-arachidonic acid (AA) to 6-keto PGF1 alpha (PGI2), PGE2, and 12L-hydroxy-5,8,10,14-eicosatetraenoic acid (HETE) was determined using thin-layer radiochromatography. Angioplasty caused a 70% decrease in vessel wall PGI2 production and a 44% decrease in PGE2 production (n = 4, p less than 0.05). Reductions in in vitro conversion of 14C-AA to PGI2 and PGE2 induced by angioplasty were comparable to that produced by cyclooxygenase inhibition with aspirin. Angioplasty, in addition, caused a 104% increase in vessel wall HETE production (n = 4, p less than 0.05). Therefore, angioplasty results in a local derangement of AA metabolism characterized by decreases in vasodilator prostaglandins and increases in vasoconstrictor hydroperoxy acids. These local changes may contribute, in part, to sudden arterial occlusion after angioplasty.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1983

Maximal postextrasystolic potentiation following multiple extrasystoles: a simple means of myocardial assessment.

To obtain consistent, reproducible postextrasystolic potentiation (PESP), a single closely coupled extrasystole (ES) must be introduced using transvenous pacing. We hypothesized that multiple ES (spontaneous or catheter induced) produce maximal PESP at all coupling intervals (CI). Differences in PESP between single and double ES were assessed in dogs at varying CI by two different methods [systolic time intervals--PEP/LVET, and endocardial markers--ejection fraction (EF)]. Single ES produced variable decreases in PEP/LVET (-8.6 +/- 2.7% (SE) to -22.9 +/- 4.0%) depending on the CI duration. Double ES produced maximal decreases (-26.0 +/- 1.2%) at all CI. A similar relationship was noted for EF following single ES (8.6 +/- 2.7% to 43.0 +/- 4.0%) and double ES (42.9 +/- 1.3%). Double ES produced maximal PESP at all CI. This finding may allow simple myocardial assessment during routine left ventricular catheterization without simultaneous right ventricular catheterization.

Animals↗
PubMed1983

Nonsurgical placement of arterial endoprostheses: a new technique using nitinol wire.

A new type of endovascular prosthesis has been developed using a unique metal alloy (nitinol) with a heat-sensitive memory. Nitinol wire coil grafts were straightened in ice water and passed into the canine aorta via catheter, where they reformed into their original shapes. Follow-up aortograms demonstrated long-term patency with minimal thrombus formation. Nitinol endovascular coil grafts may eventually be used in the nonsurgical treatment of several forms of vascular disease.

Alloys↗
PubMed1983

Patency of the ductus arteriosus after balloon dilatation: an experimental study.

Balloon dilatation of the ductus arteriosus was carried out in vivo in newborn pigs and on postmortem specimens from humans and piglets. The ductus was functionally closed in all newborn animals but patency resulted in all animals after balloon dilatation. Left-to-right shunts of 50% to 70% were found with anatomic lumen sizes of 3 to 5 mm. Patency was demonstrated up to 6 weeks after dilatation. Histologic examination showed splitting of the internal elastic layer and media, areas of hemorrhage confined to the media, and preservation of the adventitia. Mediastinal hemorrhage did not occur. This new technique is useful as an animal model of patent ductus arteriosus and could theoretically be used for palliative treatment of ductus-dependent congenital heart disease.

Angioplasty, Balloon↗
PubMed1983

Effect of aspirin on angioplasty-induced vessel wall hyperemia.

Angioplasty produces a persistent 20-fold increase in blood flow through mural vasa vasorum. To assess the role of prostaglandins in this phenomenon, vessel wall blood flow in experimentally dilated carotid arteries of aspirin treated dogs was measured. Aspirin (10 mg/kg, intravenously) significantly attenuated the increase in blood flow produced by dilation (+283 +/- 91% SE, n = 6) when compared to non-aspirin-treated controls (+2356 +/- 885% SE, n = 10). This suggests that aspirin, by interfering with arachidonate metabolism, may decrease local vasodilation after angioplasty. The effect of aspirin therapy on the long-term success of angioplasty requires further study.

Angioplasty, Balloon↗
PubMed1983

A new percutaneous vena cava filter.

A new, percutaneous vena cava filter was developed and tested in 11 dogs. Nitinol wire (0.045 cm diam) spirals were straightened and passed through an 8 French Teflon catheter into the inferior vena cava. The filter resumed its original spiral shape on warming to body temperature and was left in place up to 6 weeks. Long-term patency and capture of injected radiopaque clots were demonstrated. This new filter design may be a simple alternative to currently used implants.

Animals↗