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Biomedical subjects

W H Pearce

Publications and source records attributed to W H Pearce.

137 records · Page 8Linked to original sources
PubMed1983

A comparison of digital subtraction angiography and noninvasive testing in the diagnosis of cerebrovascular disease.

Among the 1,892 patients who underwent cerebrovascular digital subtraction angiography at our hospital over the past 18 months, there was a subgroup of 34 patients (65 carotid arteries) for whom noninvasive cerebrovascular test results and standard cerebral arteriograms were also available. These patients were reviewed retrospectively and the ability of both methods to detect hemodynamically significant lesions, defined as a greater than 50 percent reduction in the diameter of the carotid artery, was determined using the arteriograms as the "gold standard." Noninvasive cerebrovascular tests had a sensitivity of 81 percent, a specificity of 95 percent, a positive predictive value of 92 percent, a negative prediction value of 88 percent, and an overall accuracy of 89 percent. Digital subtraction angiography had a sensitivity of 84 percent, a specificity of 92 percent, a positive predictive value of 88 percent, a negative predictive value of 89 percent, and an overall accuracy of 89 percent. If the four cases of hemodynamically significant stenosis of the carotid siphon not detected by digital subtraction angiography had been considered as false-negatives, its sensitivity would have been reduced to 72 percent. In patients with hemispheric cerebral ischemia, we found noninvasive cerebrovascular tests neither necessary nor cost-effective. Digital subtraction angiography, on the other hand, often provided definitive diagnostic information in such patients if the intracranial circulation was well defined and the extracranial lesion corresponded to the patients' symptoms. Noninvasive cerebrovascular testing was the safest and most cost-effective technique for screening patients with asymptomatic bruits, atypical, nonhemispheric cerebral symptoms, and those who have undergone carotid endarterectomy. If the noninvasive cerebrovascular test result was positive or equivocal, digital subtraction angiography was performed to localize the responsible lesion and exclude carotid occlusion.

Adolescent↗
PubMed1983

Modified technique of obturator bypass in failed or infected grafts.

The obturator bypass graft operation can be performed in a moderately simplified manner by a technique that allows extension of indications for the procedure beyond situations in which sepsis is present in the groin. Long-term analysis of the results of the cases available for study indicates that the procedure may very well be a permanent reconstruction, and that graft failure results from graft infection or insufficient distal runoff, as in other distal revascularization procedures. No significant change in ankle pressure is noted when the hip is placed in maximum flexion position.

Aged↗
PubMed1983

The use of operative prebypass arteriography and Doppler ultrasound recordings to select patients for extended femoro-distal bypass.

Of 113 preoperative arteriograms analyzed, 46 (40%) were unsatisfactory to determine operability for femoral-distal bypass. In 23 of these 46 arteriograms, there was complete nonvisualization of calf vessels (Group A) and in the remaining 23, there was limited visualization (Group B). Both prebypass, on-table operative arteriography and Doppler ultrasound recordings were helpful in predicting the best available artery for bypass in all but one patient (4%) in Group A. In Group B, 7 of 23 patients had the site of distal anastomosis altered after prebypass, ontable arteriography. There was no statistical difference in the patency rates of grafts in patients with inadequate visualization (Groups A and B) and those with adequate visualization (67 patients, Group C). Prebypass, on-table operative arteriography, supplemented by preoperative Doppler ultrasound recordings, helps to extend operability and to avoid unnecessary amputation.

Angiography↗
PubMed1983

Thoracic and abdominal injuries in skiers: the role of air evacuation.

The increasing popularity of skiing as a recreational sport has resulted in a greater number of major thoracic and abdominal injuries. These injuries, unlike the more common orthopedic injuries, are often life threatening. This 8-year study reviews 44 thoracic and abdominal ski injuries managed at an urban trauma center since the inception of a helicopter air evacuation program with in-flight resuscitation capabilities. Twenty-five per cent of the injured had signs of hemorrhagic shock, and nearly 60% required a major operation. The injuries were caused by high-speed collisions with stationary objects or other skiers and by falls. Three were penetrating injuries. Organs injured were: heart, lung, kidney, spleen, liver, rectum and abdominal wall, and more than half were multiple injuries. Almost half had associated orthopedic trauma. Resuscitation was initiated on helicopter arrival in these seriously injured patients (78% of helicopter-transported patients came to operation), and apparently contributed to the low mortality of 4.5%.

Abdominal Injuries↗
PubMed1983

Hemodynamic assessment of venous problems.

Objective assessment of venous function based on venous refilling time recorded by photoplethysmography (PPG) was done in 89 patients with postphlebitic syndrome (47), primary varicose veins (29), and after an episode of acute deep vein thrombosis (13). Limbs with symptomatic postphlebitic changes had a shortened venous refilling time of 15.6 +/- 11 seconds (normal greater than 20 seconds). When venographic findings (ascending and descending) in 47 patients with postphlebitic syndrome were analyzed, it was noted that femoral valve incompetence demonstrated by descending venography was a common finding (81%), even in asymptomatic limbs (85%). Venous refilling time bore no relationship to the degree of femoral venous valve reflux. However, if there were associated diseased deep veins with incompetent perforating veins, the venous refilling time was much shorter (14 +/- 4 seconds) than in limbs without calf perforating veins (27 +/- 11.9 seconds, P less than 0.05). A tourniquet was used to impede saphenous flow, and changes in refilling time were recorded in 34 limbs with varicosities of the long saphenous vein. Refilling time normalized after tourniquet application in 31 limbs (14.43 +/- 4.34 to 30.64 +/- 11.9 seconds), and all patients underwent vein stripping. Postoperative recording confirmed the improvement in venous refilling time (29.52 +/- 27.8 seconds, P less than 0.05). Thirteen patients with acute deep vein thrombosis had serial PPG tests during a follow-up period of 27 months (mean 15.8 months). Seven had initial abnormal PPG results and persistently abnormal readings, and all developed postphlebitic changes. Venous refilling time is an useful test to determine the hemodynamic significance of femoral venous valve incompetence and to assess the effect of vein stripping on varicose veins. In acute deep vein thrombosis, follow-up study may help to identify patients at risk for development of postphlebitic changes.

Femoral Vein↗
PubMedDate not supplied

Staged embolization and operative treatment of multiple visceral aneurysms in a patient with fibromuscular dysplasia--a case report.

The importance of following a prioritized sequential approach to patients with complex multianeurysm disease cannot be overemphasized. The following patient with multiple visceral aneurysms first had coil embolization of bilateral renal artery aneurysms and then operative excision of her remaining splenic artery aneurysms to minimize the potential morbidity of a larger operation. This case also demonstrates the potential for following levels of specific degradative enzymes associated with aneurysmal disease (matrix metalloproteinase-9 (MMP-9) in this case) preoperatively and postoperatively and in long-term follow-up to monitor for disease recurrence.

Aneurysm↗
PubMedDate not supplied

Morphometric analysis of the popliteal artery for endovascular treatment.

This study intended to determine the precise diameter of the popliteal artery in patients at risk for popliteal aneurysms. Accurate sizing is necessary to develop devices for endovascular treatment of popliteal aneurysms. Fifty-four patients with abdominal aortic aneurysms (AAAs) had computed tomography (CT) scans of the popliteal arteries. Age- and gender-matched control subjects were measured by ultrasound. NIH Image was used to measure the minor diameter at the adductor hiatus (proximal) and femoral condyles (midpopliteal artery). There were 4 unsuspected popliteal aneurysms (7.4%). The proximal popliteal artery was ectatic in these patients: 13.4 +/- 5.2 mm. Proximal and midpopliteal arteries were significantly larger in the other patients with AAAs compared with controls: 9.6 +/- 1.8 mm vs 7.9 +/- 1.1 mm at the hiatus (p<0.001) and 10.2 +/- 2 mm vs 7.9 +/- 0.9 mm at the condyles (p<0.001). The popliteal artery was focally larger in patients with AAAs without popliteal aneurysms. The popliteal artery was larger in men compared with women; 9.8 +/- 1.8 mm vs 8.8 +/- 1.9 mm at the hiatus (p=0.024) and 10.5 +/- 1.9 mm vs 9.0 +/- 2.4 mm at the condyles (p=0.005). The proximal popliteal artery was 2 mm larger in patients at risk for popliteal aneurysms and 5 mm larger in patients with popliteal aneurysms compared to controls. Focal ectasia of the midpopliteal artery was common. Planning for endovascular treatment of popliteal aneurysms must incorporate this striking enlargement.

Aged↗
PubMedDate not supplied

Semi-quantitative photoplethysmography in the diagnosis of lower extremity venous insufficiency.

A new standardization device has permitted calibration of the Photopulse Adaptor, thus, making venous photoplethysmography (PPG) a more accurate, semiquantitative technique. Using this device, we studied 10 normal volunteers and 151 extremities in 69 symptomatic patients We also developed a formula for calculating the slope of the venous recovery curve which took into consideration the degree of venous emptying as well as the duration of venous recovery. The PPG was "abnormal" if there was no measurable venous emptying despite effective calf contraction or if the calculated venous recovery rate (VRR) exceeded 2.0 mm/sec. VRR clearly separated normal extremities (1.28 mm/sec) from those in which venous reflux was present (3.34 mm/sec). If we had relied on measurement of venous recovery time (VRT) alone, 30% of hour normal volunteers and 52% of our symptomatic patients would have been misdiagnosed. We feel that these modifications have made PPG a more accurate technique less subject to the vagaries of arterial inflow, and thereby more valuable to the vascular surgeon in elucidating venous pathophysiology and following the results of his therapy.

Adolescent↗