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Biomedical subjects

M C Donaldson

Publications and source records attributed to M C Donaldson.

At least 73 records · Page 4Linked to original sources
PubMed1990

Observations on the use of thrombolytic agents for thrombotic occlusion of infrainguinal vein grafts.

Vein graft failure remains a major challenge for the vascular surgeon. Thrombolysis of occluded vein grafts has shown promising short-term results in restoring vein graft patency, however, the long-term results are not established. This study examines the long-term patency and limb salvage after successful thrombolysis and revision of 22 thrombosed vein grafts in 21 patients. There were 17 men and four women with an average age of 60 years (38 to 77 years). Failed vein grafts had an average primary patency of 19 months (1 to 84 months) and included eight in situ grafts and 14 non-in situ grafts. Twelve grafts were to the popliteal level, whereas 10 were infrapopliteal. Thrombolytic agents used included urokinase (15), tissue plasminogen activator (5), and streptokinase (2). After successful thrombolysis, 19 grafts underwent 26 additional procedures including percutaneous transluminal angioplasty (9), vein patch angioplasty (4), vein interposition or jump extension graft (9), or other procedures (4). Three patients had no additional procedure, but one was placed on sodium warfarin (Coumadin). After successful initial vein graft salvage, life-table analysis revealed a 36.6% +/- 11.9% patency at 1 year and a 22.9% +/- 11.6% patency at 3 years. After secondary failure six patients had further interventions contributing to an improved limb salvage of 66.9% +/- 11.6% at 1 year and 60.3% +/- 19.0% at 3 years. The results suggest that thrombosed vein grafts initially salvaged with thrombolysis and revision do not have a favorable long-term patency, and that a premium must be placed on the detection of the failing vein graft before thrombosis.

Adult↗
PubMed1990

Screening for hypercoagulable states in vascular surgical practice: a preliminary study.

The prevalence and importance of hypercoagulable states in the general vascular surgical population is unknown. Antithrombin III, protein C, protein S, plasminogen, lupus-like anticoagulant, and heparin-induced platelet activation were determined prospectively in 158 patients with aneurysmal (27), renovascular (1), cerebrovascular (28), aortoiliac (31), or infrainguinal (71) disease. Sixteen abnormal test results were obtained in 15 patients (9.5%) as follows: deficiencies of antithrombin III (2), protein C (4), and protein S (1) and presence of lupus-like anticoagulant activity (5) and heparin-induced platelet activation (4). Reconstructive surgery was performed in 137 of the study patients. Five reconstructions, all infrainguinal bypass grafts, suffered thrombosis within 30 days. Early graft thrombosis occurred in three (27%) of 14 patients with abnormal preoperative test results compared to two (1.6%) of 123 patients with normal testing (p less than 0.01). Of the three patients with abnormal test results and graft thrombosis, lupus-like anticoagulant was detected in two and heparin-induced platelet activation in one. This preliminary study supports routine preoperative screening for lupus-like anticoagulant and heparin-induced platelet activation in patients undergoing infrainguinal reconstruction. Hypercoagulable states appear to be sufficiently common and important in the general vascular surgical population to warrant further investigation.

Adult↗
PubMed1990

Selective evaluation and management of coronary artery disease in patients undergoing repair of abdominal aortic aneurysms. A 16-year experience.

Reduction of cardiac mortality associated with abdominal aortic aneurysm (AAA) repair remains an important goal. Five hundred consecutive urgent or elective operations for infrarenal nonruptured AAA were reviewed. Patients were divided into three groups based on preoperative cardiac status: group I (n = 260, 52%), no clinical or electrocardiographic (ECG) evidence of coronary artery disease (CAD); group II (n = 212, 42.2%), clinical or ECG evidence of CAD considered stable after further evaluation with studies such as dipyridamole-thallium scanning, echocardiography, or coronary arteriography; group III (n = 28, 5.6%), clinical or ECG evidence of CAD considered unstable after further evaluation. Group I had no further cardiac evaluation and groups I and II underwent AAA repair without invasive treatment of CAD. Group III underwent repair of cardiac disease before (n = 21) or coincident with (n = 7) AAA repair. In all instances, perioperative fluid volume management was based on left ventricular performance curves constructed before operation. The 30-day operative mortality rate for AAA repair in all 500 patients was 1.6% (n = 8). There was one (0.4%) cardiac-related operative death in group I, which was significantly less than the five (2.4%) in group II (p less than 0.02). Total mortality for the two groups were also significantly different, with one group I death (0.4%) and seven group II deaths (3.3%), (p less than 0.02). These data support the conclusions that (1) the leading cause of perioperative mortality in AAA repair is myocardial infarction, (2) correction of severe or unstable CAD before or coincident with AAA repair is effective in preventing operative mortality, (3) patients with known CAD should be investigated more thoroughly to identify those likely to develop perioperative myocardial ischemia so that their CAD can be corrected before AAA repair, and (4) patients with no clinical or ECG evidence of CAD rarely die of perioperative myocardial infarction, and thus selective evaluation of CAD based on clinical grounds in AAA patients is justified.

Aorta, Abdominal↗
PubMed1990

Early detection of saphenous vein arterial bypass graft stenosis by color-assisted duplex sonography: a prospective study.

We propose a simple and rapid technique for the postoperative surveillance of developing stenosis in lower extremity saphenous vein arterial bypass grafts that uses color-assisted duplex sonography. Color Doppler flow images are used to identify points of altered flow dynamics. These points are subsequently analyzed by duplex sonography, with doubling of the peak systolic velocity at the point of suspected stenosis considered the diagnostic threshold for significant stenosis. A segment-by-segment comparison made with arteriography in 14 patients (15 grafts, 92 segments) showed this approach to be 95% sensitive (18/19) and 100% specific (73/73) for the detection and localization of focal graft stenoses that involve greater than 50% narrowing of the lumen diameter. We conclude that color-assisted duplex sonography can accurately detect the presence of saphenous vein arterial bypass graft stenoses.

Aged↗
PubMed1990

Determination of the extent of lower-extremity peripheral arterial disease with color-assisted duplex sonography: comparison with angiography.

Color-assisted duplex sonography combines color Doppler flow imaging with duplex sonography to rapidly survey the vasculature. Color Doppler sonography displays the motion of flowing blood on a sonogram and is used to visualize directly arterial lumen narrowing of greater than 50%. Absence of Doppler signals signifies arterial occlusion. Preangiographic triage of patients for surgical or interventional therapy requires that a rapid and accurate survey be performed of the extent of arterial disease. Color-assisted duplex sonography was applied prospectively in 17 consecutive patients with the clinical diagnosis of peripheral arterial disease who had not previously undergone angiography. Results of angiography of the femoropopliteal arteries were graded and localized in one of seven approximately equal arterial segments. These were compared with similar segmental maps made with sonography. For the detection of stenosis or occlusion in any of the 238 segments, the sensitivity was 0.88 (49/56), specificity 0.95 (173/182), and accuracy 0.93 (222/238). The average time taken to survey both limbs was 29 min. We conclude that color-assisted duplex sonography is an accurate and rapid tool for the noninvasive mapping of the extent of femoropopliteal arterial disease.

Adult↗
PubMed1989

What is the proper role of polytetrafluoroethylene grafts in infrainguinal reconstruction?

Polytetrafluoroethylene grafts have been used extensively for infrainguinal vascular reconstruction either as the conduit of choice or as a substitute when saphenous vein is unavailable. Although numerous studies have shown satisfactory early patency rates, the long-term efficacy of these grafts in a large number of patients for specific indications and in various positions has been less well defined. From 1977 to 1987 we used four PTFE grafts from three different manufacturers to perform 300 infrainguinal reconstructions on 240 patients on our vascular service. The indications for surgery were disabling claudication in 28% and limb salvage in 72%. The 30-day operative mortality of 1% was not different from the 1.4% associated with infrainguinal autogenous vein grafting. The 5-year cumulative patency rate achieved with all infrainguinal polytetrafluoroethylene grafts was 35%, significantly higher for grafts placed for claudication (57%) than those placed for limb salvage (24%). There were no significant differences between the above-knee and below-knee locations for distal anastomoses regardless of indication, but femoropopliteal grafts provided significantly higher 5-year patency (37%) than infrapopliteal grafts (12%). Comparison of the 5-year patency rates among the three manufacturers of polytetrafluoroethylene grafts showed no significant differences. Fifty-four polytetrafluoroethylene grafts that failed underwent 67 revisions after catheter thrombectomy or thrombolysis, which resulted in a minimal 11% 5-year patency rate. Based on this experience, it is concluded that infrainguinal polytetrafluoroethylene prostheses provide significantly inferior results when compared with autogenous reconstruction.

Adult↗
PubMed1989

Pulsatile masses surrounding vascular prostheses: real-time US color flow imaging.

A prospective evaluation of color flow mapping and real-time ultrasound was performed to determine if pseudoaneurysms could be distinguished from other causes of masses surrounding vascular grafts of the lower extremities. Twelve palpable pulsatile masses were imaged. Diagnoses were confirmed at angiography (n = 11), computed tomography (n = 7), aspiration biopsy (n = 5), and operative intervention (n = 6). A swirling pattern of blood flow was seen in six of seven cases of pseudoaneurysm. Lack of flow signals was noted in four of the five collections representing hematoma (n = 2) or infection (n = 2). The seventh case was later shown to be an infected, thrombosed pseudoaneurysm. The single false-positive diagnosis was made early in the series when the flow signals detected were due to transmitted arterial pulsations. The authors conclude that color Doppler flow imaging is useful in the differential diagnosis of pulsatile masses associated with prosthetic grafts. Prosthetic graft pseudoaneurysms have a specific appearance of swirling blood flow arising from a wide neck and are distinguishable from traumatic or iatrogenic pseudoaneurysms of the native vascular tree.

Aged↗
PubMed1988

Femoropopliteal reconstruction for claudication. The risk to life and limb.

The current study was undertaken to examine the results of femoropopliteal bypass grafting with intermittent claudication as the indication. Of 1173 infrainguinal reconstructions carried out on our service during the past decade, 249 (21%) consecutive femoropopliteal grafts were performed for disabling claudication in 191 patients. The primary five-year cumulative patency rates were 78% for autogenous vein and 52% for polytetrafluoroethylene grafts. There were two (0.8%) 30-day operative deaths and a subsequent five-year amputation rate of 2.4% for both groups. Femoropopliteal reconstruction for claudication may therefore be carried out with acceptably low operative mortality and a subsequent amputation rate comparable with that anticipated from the natural history of the disease. While the five-year patency rate is significantly higher utilizing autogenous vein grafts, symptomatic relief may be expected with prosthetic grafts in approximately half the patients without incurring a higher risk of limb loss.

Adult↗
PubMed1987

Recent experience with the asymptomatic cervical bruit.

To document our recent experience with asymptomatic cervical bruit, we reviewed the records of 418 patients referred to the noninvasive vascular laboratory. Mean follow-up of 23.7 months was obtained for 370 patients by record review or telephone. In a group of 313 patients not operated on, transient ischemic attacks occurred in 14 and stroke in seven (6.7%). The risk of neurologic morbidity was highest in patients with advanced carotid stenosis. Carotid endarterectomy was performed 62 times in 57 patients, with one stroke (1.6%). If carotid endarterectomy is performed with low morbidity, identification of selected surgical candidates with advanced carotid stenosis is reasonable.

Auscultation↗
PubMed1987

Markers of thrombotic activity in arterial disease.

Levels of the platelet degranulation product beta-thromboglobulin (BTG) and the fibrinogen degradation product fibrinopeptide A (FPA) were measured in 26 asymptomatic subjects (group 1), 17 patients with peripheral vascular disease (PVD) (group 2), and 12 patients with PVD and bypass grafts (group 3). Mean BTG and FPA levels were elevated in both groups 2 and 3, indicating increased thrombotic activity in patients with PVD. Results of serial BTG and FPA assays in group 3 patients suggested a trend downward. These markers may be useful for estimating disease severity and prognosis, extent of graft healing and patency, and efficacy of therapeutic intervention.

Arterial Occlusive Diseases↗
PubMed1986

Axillofemoral bypass: a tool with a limited role.

Axillofemoral bypass (AXB) was performed on 100 patients who had claudication (19), pain at rest (42), gangrene or ulcer (22), aortic sepsis (14), or unresectable abdominal aneurysm (3). Unilateral (27 grafts), double unilateral (1), or axillobifemoral (72) grafts with Dacron (58), polytetrafluoroethylene (PTFE) (28), ring-supported Dacron or PTFE (12), or other material (2) were performed by 13 surgeons. Eight patients died within 30 days and three major amputations were necessary. Fifty-two (57%) of the 92 survivors had a total of 92 graft complications during a mean follow-up period of 21.5 months. Thirty-two patients underwent 57 reoperations of various types, incurring an additional three deaths and three amputations. Sixty (65%) of the original 92 survivors of AXB avoided reoperation. The 89 patients who survived the original and repeat procedures were followed up through the end of 1984 (62 patients), to late death (23), or to late graft removal (4), whichever occurred first. At these end points, 83 of the 89 (93%) patients had patent grafts. The graft patency rate of the original 100 AXBs by life table was 54% at 36 months; but with reoperation, it was 72%. Among those patients who left the hospital after AXB, the survival rate at 36 months was 69%. Statistically insignificant trends toward improved early patency were noted with bilateral femoral anastomoses, total iliac occlusion, and less severe ischemia. AXB provided safe palliation of severe arterial disease, with overall graft patency exceeding postoperative patient survival according to life-table analysis. However, the safety of AXB was tempered by frequent complications and the necessity for many reoperations to provide maximum efficacy.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1985

Hypertension from isolated thoracic aortic coarctation associated with neurofibromatosis.

A 14-year-old boy presented with hypertension and symptomatic cervical root neurofibromatosis. Isolated thoracic aortic coarctation and large collaterals adjacent to the cervical spine were identified. Surgical correction of the coarctation allowed safe excision of the neurofibroma and reversal of hypertension. Hypertension in the presence of neurofibromatosis requires evaluation of a number of correctable etiologies.

Adolescent↗
PubMed1985

Unusual presentation of DDD pacemaker system malfunction.

A DDD pacemaker utilizing an atrial J electrode was implanted in a patient whose right atrial appendage had been removed 7 years prior during aortic valve replacement. Alternating QRS morphologies produced by pacemaker stimulus artifacts occurred as a consequence of atrial lead dislodgement. The screw-in atrial electrode has superior stability in patients with right atrial appendage removal; stability of the atrial J electrode cannot be obtained in such cases.

Electrocardiography↗