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Biomedical subjects

W H Pearce

Publications and source records attributed to W H Pearce.

At least 109 records · Page 6Linked to original sources
PubMed1991

Excimer laser-assisted femoral angioplasty: early results.

The ability to ablate atheroma without generating heat makes the excimer laser wavelength a promising intraluminal technique for the treatment of arterial occlusive disease. This series reviews a preliminary experience treating patients with superficial femoral arterial disease admitted with limb-threatening ischemia or claudication. Twenty-six diseased superficial femoral arteries (5 stenotic and 21 occluded) were treated in 23 consecutive patients. Patients with claudication (18) reluctant to undergo bypass or with limb-threatening ischemia (8) at extremely high risk for surgery were included. There were 10 men and 13 women with a mean age of 67 years. A 308 nm excimer laser with an over-the-wire catheter (19) or balloon-centered end-on catheter (7) was used followed by balloon angioplasty. Twenty-four procedures were performed percutaneously, and two were performed with the vessel open in the operating room. Technical success, defined as disobliteration confirmed by angiography and greater than 0.15 increase of the ankle/brachial index, was achieved in 15 of 26. Eleven of 21 occlusions (52%) and four of five stenoses (80%) were opened. Only two of 11 lesions longer than 10 cm were successfully treated. Unsuccessful attempts (technical failure) occurred in 11 of 26 patients and resulted in four elective and one emergency femoral-popliteal bypass. Five patients were discharged with their claudication unchanged, and one had an elective amputation. Six arterial perforations with three arteriovenous fistulas occurred, all resolved without operation. No unanticipated limb loss occurred. In the 15 successful cases, the mean ankle/brachial index increase was 0.34. Seven (47%) of these 15 remain patent with a mean follow-up of 9.5 months (1.5 to 14 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Aneurysm or occlusive disease--factors determining the clinical course of atherosclerosis of the infrarenal aorta.

Atherosclerosis of the infrarenal aorta results in distinct clinical entities--aortoiliac occlusive disease (AOD) and abdominal aortic aneurysm (AAA). Although loss of collagen has been implicated in AAA, collagen accumulation plays a role in AOD. In vivo collagen-gene expression can be assessed using complementary DNA for collagen types I and III alpha-chains. The purpose of this study is to compare total collagen (type I + III) and collagen types I and III messenger RNA in AAA, AOD and normal aorta. Specimens were collected from the infrarenal aorta during operation for AOD (n = 7), AAA (n = 7), autopsy, or organ procurement (normal; n = 7). Northern transfer analysis of total RNA was used to compare mRNA levels for type I and III collagen. After preliminary extraction, specimens were hydrolyzed for hydroxyproline analysis used to calculate total collagen (type I + III). Relative levels of type I (pro-a1[1]) mRNA were greater in both AOD (0.77 +/- 0.35) and AAA tissue (0.94 +/- 0.24; p = 0.6) than in normal aorta (0.02 +/- 0.03). Type III (pro-a1[III]) mRNA levels were also greater in AOD (2.52 +/- 0.19; p = 0.09) and AAA tissue (3.15 +/- 1.3) than in normals (0.97 +/- 0.47). Total collagen concentration was increased in AOD (45.6% +/- 3.1% dry weight; p less than 0.05) but not AAA tissue (27.8% +/- 4%) when compared to normal aorta (34.7% +/- 2.3%). Collagen type I and III gene expression is greater in older, diseased aorta, yet collagen accumulated only in AOD. This implies a similar synthetic response in both AOD and AAA. Thus, proteolytic degradation in AAA appears to determine collagen content and possibly the clinical course of the atherosclerotic process.

Aged↗
PubMed1991

Spontaneous aorto-left renal vein fistula: the "abdominal pain, hematuria, silent left kidney" syndrome.

Spontaneous aorto-left renal vein fistula (ALRVF) is a rare occurrence; with this case, only 16 have been reported to date. Common features in patients with ALRVF include abdominal pain (81%), hematuria (100%), impaired renal function (85%), and nonvisualization of the left kidney (100%). Less common but also present in the majority of cases are a left sided bruit (73%), pulsatile abdominal mass (63%), and proteinuria (50%). Also important, 94% have a retroaortic left renal vein, unlike the six cases of traumatic ALRVF that have been reported. This magnifies the diagnostic value of contrast abdominal computed tomographic scanning, which demonstrates not only the anomalous location of the left renal vein but also the abdominal aortic aneurysm and poor enhancement of the left kidney. These findings rule out the possibility of the "nutcracker syndrome" (left renal vein compression between aorta and superior mesenteric artery). Although confirming the presence of a fistula by early caval opacification, aortography does not always distinguish ALRVF from the more common aortocaval fistula. This can be accomplished by Duplex scanning with deep probes and even preferably color coding of velocity signals. With such precise preoperative localization, surgical repair is relatively easy and safe.

Abdominal Pain↗
PubMed1990

A comparative study of intraoperative angioscopy and completion arteriography following femorodistal bypass.

A prospective comparison of the findings on standard completion arteriography with those seen using videoangioscopy was done following 49 cases of "femorodistal" bypass grafting in 47 patients. The two techniques were compared with respect to the detection of technical defects, modification of the surgical procedures, early graft patency (72 hours), and complications. Completion arteriography was specific (95%) but only moderately sensitive (67%) compared with angioscopy for detection of technical problems. Following angioscopy, significant alterations in the surgical procedure were noted in 5 (10%) of the 49 cases. Early graft failure occurred in 3 (6.1%) cases but none were identifiably due to technical problems. Four patients suffered postoperative myocardial infarctions, 2 (4.2%) of which were fatal; no patients had contrast-induced allergies or renal failure. Angioscopy was measurably more accurate for the detection of technical problems than completion arteriography, but offered little information about distal arterial anatomy that may have an impact on graft patency or the use of antithrombotic therapy.

Aged↗
PubMed1990

Scalene muscle abnormalities in traumatic thoracic outlet syndrome.

Thoracic outlet syndrome (TOS) is not a single disorder but a collection of abnormalities in the same anatomic area that elicit similar symptoms. The many causes of TOS are best classified into one of three groups: osseous, traumatic, and nontraumatic. Although patients with traumatic TOS constituted 86% of our last 600 patients with TOS who underwent surgical treatment, the precise mechanism underlying the condition remains obscure. To determine if there was microscopic abnormalities, 45 anterior and middle scalene muscles from patients with traumatic TOS were studied by means of histochemical stains applied after freezing of the muscles. The results revealed a consistent abnormal histologic pattern in patients with traumatic TOS: type II fibers were atrophied; there was an increase in the average number of type I fibers (78% versus 53% in muscles from control patients); and there was a significant increase (mean: 36%) in connective tissue (muscles from control patients averaged less than 15%). Although type II fiber atrophy and type I fiber predominance are seen in a variety of other conditions, their association with fibrosis is rare. Following neck injuries, the changes in the anterior and middle scalene muscles are compatible with trauma, suggesting that fibrotic scalene muscles are an important cause of symptoms in traumatic TOS.

Adult↗
PubMed1990

Distal embolization as a presenting symptom of aortic aneurysms.

The records of 302 patients who underwent abdominal aortic aneurysm (AAA) repair between 1985 and 1990 were reviewed. Two hundred and forty-eight patients (82%) were asymptomatic, while 32 patients (11%) had ruptured aneurysms. During this period, 15 patients (5%) presented with distal embolization as the first manifestation of their AAA. The preoperative embolic event resulted in limb-threatening ischemia in 3 patients, digital ischemia in 11, and calf myonecrosis in 1. CT scan was performed in 14 of 15 patients demonstrating irregular, heterogeneous thrombus within the AAA. Only two of the AAAs were larger than 5 cm. Angiography demonstrated occlusive lesions but was not diagnostic for AAA in seven patients and resulted in three episodes of embolization. AAA was repaired with a tube graft in 4 patients while a bifurcated graft was required in 11 patients for aneurysmal (in 4 patients) and occlusive disease (in 7 patients) of the iliac arteries. All cases employed a transperitoneal approach, systemic heparin, and distal occlusion prior to aortic clamping. Complications included three major (below-knee) and five minor amputations, developing or worsening renal failure in five patients (33%), and death in two (13%). In comparison, mortality was 5% for elective repair and 66% for rupture during this same period. CT scan was safer and more informative than angiography. The morbidity of patients with AAA presenting with emboli is comparable with rupture. The risk of embolization does not correlate with size and indicates the potentially dangerous nature of small AAAs.

Aged↗
PubMed1990

Noninvasive evaluation of the upper extremity.

Vascular problems of the arm and hand can be assessed by a number of noninvasive modalities that are chosen on the basis of the history and physical examination. For suspected upper-extremity ischemia, we begin with SLPs and velocity-waveform analysis. The former test will define the extent and approximate location of the disease process, and subjective assessment of the waveform will further determine the degree and location of occlusive disease. When digital ischemia is suspected, the Doppler examination combined with intermittent compression of the radial and ulnar arteries is valuable for defining the variable arterial anatomy of the hand and the patency of the common and proper digital arteries. The extent of distal ischemia can be assessed by digital pressures. Duplex scanning has been found to be of value in determining the source of upper-extremity micro-emboli, in imaging suspected aneurysmal changes, and for evaluating arteriovenous fistulae and bypass grafts. Cold testing is used to confirm the diagnosis of Raynaud's disease after excluding proximal occlusive disease. When symptoms suggest intermittent arterial obstruction, arterial compression at the thoracic outlet is assessed by monitoring the arterial waveform during a series of maneuvers that change the anatomy of the outlet. Although a combination of IPG and venous Doppler examination accurately identifies venous occlusion, we routinely use duplex scanning in this setting. In addition to providing both anatomic and hemodynamic information about the subclavian vein, the jugular vein and the junction of the innominate vein can also be studied. Because of its ability to image in a coronal plane, MRI scanning is another nonivasive study that we have found useful for evaluation of venous anatomy and patency of the subclavian, jugular, and innominate veins. Venous thrombosis, often the first manifestation of subclavian vein compression at the thoracic inlet, is best evaluated using duplex scanning.

Arm↗
PubMed1990

Computed tomography for evaluation of arterial disease in the popliteal fossa.

The clinical details, arteriograms, and computerized tomographic (CT) scans of 28 patients with popliteal arteriopathies were reviewed retrospectively to determine the usefulness of CT for the diagnosis and treatment of these disorders. Arteriography diagnosed 70% and CT diagnosed 98% of the 45 popliteal disorders. Popliteal aneurysms were not detected by arteriography because of occlusion in seven (20%) patients and intraaneurysmal thrombus that produced no luminal compromise in two. Thrombus was identified by CT in 22 of 24 patient aneurysms and suspected as the source of digital embolization in 7. Graft aneurysms were identified by CT in two cases, but one was not detected by arteriography because of graft occlusion. Two mycotic aneurysms were identified, one by arteriography and not by CT because of misinterpretation of a periarterial hematoma. Popliteal entrapment was diagnosed by CT in three cases, and in two cases occlusion precluded diagnosis of entrapment by arteriography. Adventitial cystic disease was diagnosed accurately by CT in three cases, and in two there were no characteristic arteriographic abnormalities. In cases of entrapment and cystic disease, the CT findings allow the surgeon to plan his approach through a posterior incision, which in these two instances facilitates surgical technique. CT provides detail of the arterial wall, intraarterial contents, and surrounding musculoskeletal anatomy, all of which are useful for accurate evaluation of arterial disorders of the popliteal fossa.

Adult↗
PubMed1990

Human abdominal aortic aneurysms. Immunophenotypic analysis suggesting an immune-mediated response.

Cellular immunity may play a role in the pathogenesis of atherosclerosis. In this report the potential role of these cells in the formation of abdominal aortic aneurysms by immunohistochemistry was investigated. Aortic tissues from 32 patients were examined: 4 normal aortas, 6 aortas with occlusive atherosclerotic disease, 17 abdominal aortic aneurysms, and 5 inflammatory abdominal aneurysms. Using monoclonal anti-CD3 (T cells), anti-CD19 (B cells), anti-CD11c (macrophages), anti-CD4 (T helper cells), and anti-CD8 (T suppressor cells), several distinctions among these groups were found. The amount of inflammatory cell infiltrate was as follows: inflammatory aneurysms more than abdominal aortic aneurysms more than occlusive aortas more than normal aortas. CD3-positive T lymphocytes rarely were found in the adventitia of normal or occlusive aortas. In contrast, abdominal aortic aneurysms and inflammatory aneurysms exhibited most of the CD3-positive infiltrates in the adventitia. CD19-positive B lymphocytes were present mainly in the adventitia of all pathologic tissues. The CD4-positive:CD8-positive ratio was greater in abdominal aortic aneurysms and inflammatory aneurysms than in the other groups, both in the adventitia and in the media of the aortas. CD11c-positive macrophages were present throughout the diseased tissues, often surrounded by lymphoid aggregates; the greatest numbers of macrophages were found in the inflammatory aneurysm group. Our data suggests that the aneurysmal disease may progress from occlusive disease and is accompanied by an increase in chronic inflammatory cells as well as a redistribution of these cell types. Therefore it is suggested that aneurysmal disease may represent an immune-mediated event.

Antibodies, Monoclonal↗
PubMed1990

Recurrent thoracic outlet syndrome.

Recurrent symptoms develop in 15% to 20% of patients undergoing either first rib resection or scalenectomy for thoracic outlet syndrome. Over the past 22 years 134 operations for recurrence were performed in 97 patients. Four operations were used: transaxillary first rib resection (26); supraclavicular first rib resection with neurolysis (15); scalenectomy with neurolysis (58); and brachial plexus neurolysis (35). Complications included temporary plexus injury (0.7%), temporary phrenic palsy (3.7%), and permanent phrenic palsy (1.4%). The combined primary success rate of all four operations for recurrence was 84% in the first 3 months. This fell to 59% at 1 to 2 years; 50% at 3 to 5 years; and 41% at 10 to 15 years. No significant difference was found in results between the four operations used for recurrence. When recurrence was caused by trauma the results of reoperations were better than when recurrence was spontaneous. The primary success rates of three initial operations for thoracic outlet syndrome were compared to their secondary success rates (improved after reoperation). By use of life-table methods, reoperation improved the 5- to 10-year success rate of transaxillary first rib resection from 69% to 86% and for scalenectomy from 69% to 84%. Reoperation is successful in most cases of recurrent thoracic outlet syndrome and better when recurrence is the result of a neck injury.

Adolescent↗
PubMed1989

The treatment of thoracic outlet syndrome: a comparison of different operations.

Although transaxillary first rib resection is one of the popular treatments for thoracic outlet syndrome today, recurrences and nerve injuries have led to investigation of other operations that might reduce complications and improve results. This article compares the results of transaxillary first rib resection with (1) scalenectomy (anterior and middle) and (2) supraclavicular first rib resection with scalenectomy. Between 1964 and 1987, 668 primary operations were performed for thoracic outlet syndrome on 491 patients. Seventy-one percent were women. Eight-six percent gave histories of neck trauma, often a whiplash injury (traumatic thoracic outlet syndrome); 4.5% had cervical ribs. Common symptoms included paresthesia in the hands (90%); arm pain (80%); neck pain (86%); and occipital headaches (69%). On physical examination, tenderness over the scalene muscles and duplication of symptoms with the arms abducted to 90 degrees in external rotation were present in over 90% of patients. By use of life-table analysis methods, success after surgery was found to be the same for all operations: 91% to 93% at 3 months; 76% to 79% at 1 to 2 years; 70% to 73% at 3 to 5 years; and 69% to 72% at 5 to 10 years. After rib resection plexus injuries occurred in 2.6%, with partial disability in 0.5%. No plexus injuries occurred after scalenectomy, but temporary phrenic nerve palsy occurred in 4.4%. Scalenectomy is as successful an operation as first rib resection for traumatic thoracic outlet syndrome and has fewer serious complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Traumatic injuries of the brachial artery.

Sixty-four patients with traumatic brachial artery injuries were treated. Fifty had penetrating and 14 had blunt injuries. Associated extremity and torso injuries were common. Despite an excellent vascular patency rate of 97 percent, limb loss resulted from severe soft-tissue injury and functional disability occurred due to nerve injury.

Adolescent↗
PubMed1988

Carotid and vertebral arterial injuries.

Injuries of the extracranial cerebral vessels represent only a small fraction of all reported arterial injuries but pose a significant dilemma over whether to repair or ligate the involved vessel. This article reviews recognition and repair of both penetrating and blunt injuries of the carotid and vertebral arteries, with special comment on the surgical exposure of the less accessible injuries.

Carotid Artery Injuries↗
PubMed1988

Nuclear magnetic resonance imaging: its diagnostic value in patients with congenital vascular malformations of the limbs.

Congenital vascular malformations (CVMs) of the limb include simple and cavernous hemangiomas, microarteriovenous and macroarteriovenous fistulas, venous angiomas, and mixed CVMs. In differentiating these lesions, Doppler waveform analysis, labeled microsphere studies, arteriography, closed-space phlebography, and contrast-enhanced CT scans have all been advocated, but each has significant limitations. This article evaluates the ability of magnetic resonance imaging (MRI) in characterizing CVMs. Limb CVMs were evaluated by MRI in eight patients: four in the upper and four in the lower extremity. Before MRI, seven of the patients had arteriography, five had phlebography, and five had Doppler waveform analysis. MRI showed a highly cellular network with little arteriovenous flow in five patients. In four of these, arteriography and phlebography confirmed the presence of a predominantly venous or microfistulous anomaly. In the other three patients, MRI demonstrated high-flow arterial and venous channels and were confirmed by arteriography to have macrofistulous arteriovenous malformations. In all eight patients, MRI revealed the anatomic location and the longitudinal and transverse extent of the vascular malformation as well as their relationships with contiguous muscle groups, bones, and vessels. We conclude that CVMs of the limbs can be characterized accurately with MRI, with the anatomic extent, degree of cellularity, and flow characteristics readily gauged. Because MRI provides the same basic information supplied by angiography and the noninvasive laboratory and assesses anatomic extent and cellularity, it serves well as the primary diagnostic test for suspected CVMs, particularly in infants and children in whom competitive tests pose additional limitations.

Adolescent↗
PubMed1988

Aortobifemoral bypass: the operation of choice for unilateral iliac occlusion?

Aortobifemoral bypass (ABF) is the preferred operation for patients with bilateral aortoiliac occlusive disease, but for those with unilateral occlusion without significant stenosis of the contralateral iliac artery, alternative reconstructions, such as femorofemoral (FF) or iliofemoral (IF) bypass have been advocated. We compared the surgical outcome in 96 such patients after ABF (n = 32), FF (n = 47), or IF (n = 17) bypasses, with biplane arteriography and noninvasive laboratory testing used to assess the contralateral iliac artery and runoff status, in particular, patency of the superficial femoral artery (SFA). Graft patencies were assessed by noninvasive criteria and analyzed by the life-table method. The only death occurred after ABF bypass (3.1%). Primary patency rates at 1, 3, and 5 years with an open SFA were 100%, 89% and 89%, respectively, for ABF; 92%, 92%, and 92% for FF; and 71%, 71%, and 36% for IF. When the SFA was occluded, the primary patency rates at 1, 3, and 5 years were 100%, 100%, and 72%, respectively, for ABF; 72%, 53%, and 35% for FF; and 56%, 56%, and 56% for IF bypasses. There were no later occlusions on the contralateral ("good") side after ABF. Significant progression of atherosclerosis in donor iliac artery was observed in 6% of both FF and IF bypasses. We conclude that ABF is the preferred operation for extensive iliac artery occlusive disease that is hemodynamically significant only on the symptomatic side unless specifically contraindicated by prohibitive risk or abdominal disease. This is particularly true in the face of SFA occlusion.

Actuarial Analysis↗