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Biomedical subjects

M L Nix

Publications and source records attributed to M L Nix.

9 recordsLinked to original sources
PubMed1992

Is anticoagulation indicated for asymptomatic postoperative calf vein thrombosis?

The purpose of this study was to determine the effect of anticoagulation on the incidence of thrombotic propagation and pulmonary embolism in patients with calf vein thrombosis after total hip or total knee arthroplasty. Patients undergoing arthroplasties had prospective surveillance for postoperative deep vein thrombosis by both bilateral contrast venography and venous duplex scanning. Calf vein thrombosis was documented by venography in 42 patients (50 limbs), including 29 of 253 patients undergoing total hip arthroplasty (11.4%) and 13 of 99 patients undergoing total knee arthroplasty (13%). Of patients on whom follow-up duplex scans were performed, heparin followed by warfarin anticoagulation was used in 11 (13 limbs) and withheld in 21 (25 limbs). Propagation of thrombosis to the popliteal or superficial femoral vein or both was detected by serial duplex scanning in 3 of 13 treated limbs (23%) and 2 of 25 untreated limbs (8%), (p = 0.43). All thrombus propagations were detected within 2 weeks of the operative procedure. There were no pulmonary emboli or deaths. Propagation of asymptomatic calf vein thrombosis after arthroplasty was not influenced by anticoagulation, suggesting that postoperative calf vein thrombosis need not be routinely treated. Serial venous duplex scanning is useful to identify the occasional patient in whom thrombotic propagation requiring anticoagulation develops.

Aged↗
PubMed1991

Duplex scanning versus venography as a screening examination in total hip arthroplasty patients.

Combined B-mode/Doppler (duplex) scanning and venography were compared in routine perioperative screening for proximal deep vein thrombosis (DVT) in 158 total hip arthroplasty (THA) patients. Preoperative scans were performed in the first 60 patients; the low preoperative prevalence of 2% for proximal DVT was thought not to warrant routine preoperative scanning. Postoperatively, duplex scanning had a sensitivity of 79%, a specificity of 98%, and an accuracy of 97% when venography was considered as the gold standard. The postoperative incidence of proximal DVT was 12% in this group of THA patients treated with mechanical and pharmacologic prophylaxis. Including calf vein thrombosis, 30% had DVT postoperatively. This study demonstrates the efficacy of duplex scanning for diagnosing proximal DVT and describes an effective noninvasive method of screening THA patients for the presence of proximal DVT.

False Negative Reactions↗
PubMed1989

Serial noninvasive studies do not herald postoperative failure of femoropopliteal or femorotibial bypass grafts.

We performed a 5-year retrospective case-control study of 232 patients undergoing femoropopliteal (n = 188) or femorotibial (n = 44) bypass to determine if serial noninvasive studies herald postoperative graft failure. We correlated serial ankle/arm pressure indices (API) with graft patency. An interval drop in API of greater than or equal to 0.20 was considered hemodynamically significant, but interventional therapy was carried out only for clinically symptomatic graft failure and an API less than 0.20 above the preoperative value. The cumulative 5-year limb salvage rate was 82% and the patient survival was 63%. A significant drop in API did not correlate with cumulative 5-year graft patency. The 5-year cumulative primary graft patency rates were 60% and 62% in patients with stable and interval drops in API, respectively (Z = 0.15, p = N.S.) These results suggest that a significant drop in postoperative API does not predict patients with impending femoropopliteal or femorotibial graft failure. We believe that routine noninvasive surveillance and prophylactic intervention on detected asymptomatic lesions in leg bypass grafts may not be justified.

Adult↗
PubMed1989

Clinical and noninvasive assessment of venous disease as related to pulmonary embolism.

Proper management of patients with venous disease requires recognition of the various syndromes and an accurate objective diagnosis. Unfortunately many physicians are unfamiliar with the different venous disorders and are unaware of the fallibility of the clinical diagnosis of these syndromes. This article reviews the six common venous conditions that collectively are more common than coronary or peripheral arterial disease. Acute and recurrent deep vein thrombosis, postthrombotic syndrome, superficial thrombophlebitis, varicose veins, and pulmonary embolism may all confront the physician regardless of his or her specialty. Clinical recognition and differentiation of these disorders along with appropriate use of objective, noninvasive isotopic and venographic studies should lead to accurate diagnosis and management of these venous syndromes. Such an approach will permit prompt and appropriate therapy for disabling and potentially life-threatening venous thromboembolism while avoiding unnecessary anticoagulation of patients with disorders mimicking venous disease.

Acute Disease↗
PubMed1989

Perioperative asymptomatic venous thrombosis: role of duplex scanning versus venography.

We compared combined B-mode/Doppler (duplex ultrasonic scanning and venography in routine preoperative and postoperative screening for major proximal deep vein thrombosis in 78 patients undergoing total hip or knee arthroplasty. Of 309 extremity examinations, duplex scanning had an overall sensitivity of 85.7% (12/14) and a specificity of 97.3% (287/295). The preoperative prevalence and postoperative incidence of major deep vein thrombosis were 2.5% and 14.1% of patients, respectively, despite intensive mechanical and pharmacologic prophylaxis. In addition, venography documented a preoperative prevalence and postoperative incidence of isolated calf deep vein thrombosis in 2.5% and 16.7% of patients, respectively. Whereas such disease extended proximally even in the absence of anticoagulation in only 18% of patients studied by serial duplex scans, calf deep vein thrombosis accounted for the only two instances of pulmonary embolism in this study. There were no deaths related to pulmonary embolism. This study suggests that duplex scanning is useful in screening for perioperative deep vein thrombosis in patients undergoing total hip or knee arthroplasty, which carries a significant risk of venous thromboembolism despite routine prophylaxis.

Adult↗
PubMed1986

The blue toe syndrome: hemodynamics and therapeutic correlates of outcome.

We reviewed the limb and digit hemodynamics of 67 extremities of 48 patients evaluated for blue toe syndrome in our vascular laboratory during 7 years. These patients represented 1.4% of the arterial examinations during this period. Abnormal ankle/arm pressure indices (less than 0.9), signifying proximal arterial obstruction, were present in 31 limbs (47%). Toe/ankle indices were abnormal (less than 0.6) in 57 extremities (85%), indicating pedal or digital artery obstruction. Arteriograms were obtained in 40 of 64 extremities (63%) available for follow-up, which revealed atherosclerotic disease in 90% (aortoiliac 20%, femoropopliteotibial 30%, and combined 40%), aneurysm in 7.5%, and no disease in only one extremity (2.5%). Of 64 extremities followed for 1 to 84 months (mean, 26 months), only 28 (44%) manifested an uncomplicated outcome. Tissue loss was noted in 24 (38%), recurrent digital ischemia occurred in nine (14%), and 14 limbs (22%) required amputation of toe(s) (seven), forefeet (three) or legs (four). Nine patients (20%) died in the follow-up period. Outcomes did not correlate with limb or digit hemodynamics or with therapy (surgical in 31, medical in 11, or none in 22) except that tissue necrosis was more common in patients undergoing operation. The blue toe syndrome deserves recognition as an important sign of potential limb-threatening arterial disease, but the optimal therapy remains to be established.

Adult↗
PubMed1986

Recurrent versus residual carotid stenosis. Incidence detected by Doppler ultrasound.

A sterile Doppler probe was used for intraoperative monitoring of the integrity of carotid endarterectomy of 125 vessels of 107 patients. Our objective was to reduce the contribution of residual carotid lesions to recurrent stenosis, which was evaluated by Doppler spectrum analysis in the early (less than 3 months, 66 arteries) and late (3-77 months, mean 32 months, 47 arteries) postoperative period. Intraoperative Doppler monitoring detected residual occlusion in six (4.8%) external carotid arteries and stenosis in ten (8.0%) internal carotid arteries permitting selected arteriography and correction of all significant lesions. Follow-up revealed one (1.5%) asymptomatic common carotid occlusion at 6 weeks and three (6.4%) asymptomatic internal carotid stenoses at 6, 10 and 25 months after operation. When compared to previous published experience, these results suggest that intraoperative correction of residual carotid obstruction detected by Doppler ultrasound may reduce the incidence of postoperative "recurrent" carotid stenosis.

Adult↗
PubMed1985

Late outcome of untreated asymptomatic carotid disease following cardiovascular operations.

In a previous prospective study of 449 patients undergoing coronary or peripheral arterial reconstruction, 85 patients had preoperative evidence of asymptomatic bruit and/or greater than 50% carotid obstruction by routine Doppler screening. No patient had prophylactic carotid endarterectomy. This article reviews the late postoperative outcome (2 to 61 months, mean 35 months) of 67 patients with asymptomatic carotid disease who survived operation without perioperative deficit. Eleven patients died (16%) including four of myocardial infarction and two of stroke. Neurologic deficits occurred in the late postoperative period in 22 patients (32.8%) after an average interval of 31 months, including transient ischemic attacks in 15 patients (22.4%); only four of these 15 were appropriate to the side of carotid disease documented preoperatively. Seven patients (10.4%) suffered stroke, only three (4.5%) of which were in the territory of carotid disease detected preoperatively. The cumulative rate of carotid disease progression was 34%, including three patients who suffered carotid occlusion. Two of the latter had the only fatal strokes. This study suggests that patients with asymptomatic carotid disease, although not at significant risk of perioperative stroke, require careful follow-up for late postoperative neurologic deficits, the majority of which (68%) are transient ischemic attacks.

Adult↗