Mary C. Proctor

Twenty-year clinical experience with the Greenfield filter

The purpose of this study was to characterize the long-term safety and efficacy of the stainless-steel Greenfield filter. All patients who underwent Greenfield filter placement at three institutions during tenure of the senior author (L.J.G.) were entered prospectively into a filter registry and followed on an annual basis. Follow-up consisted of clinical examination to evaluate the status of venous disease or recurrence of pulmonary embolism, abdominal radiographs to determine the stability of the filter and an evaluation of the patency of the inferior vena cava and lower extremities. This report summarizes the 20-year experience. The rate of recurrent pulmonary embolism was 4% and the caval patency rate was 96%. Some filter movement of no clinical significance was seen in 8% of cases. There was no procedural mortality and morbidity was minimal. Greenfield filter insertion provides long-term protection from pulmonary embolism while preserving caval patency.

Early placement of prophylactic vena caval filters in injured patients at high risk for pulmonary embolism.

OBJECTIVE Pulmonary embolism (PE) is a major problem in patients with multiple injuries. We present our experience with early placement of prophylactic vena caval filters (VCFs). DESIGN Prospective study group with historical control. MATERIALS AND METHODS From March 1993 to December 1993, VCFs were placed in 40 consecutive patients with three or more risk factors for PE and had demographic, physiologic, venous thromboembolic prophylaxis, and outcome data collected prospectively (VCF group). They were compared to 80 injured patients admitted between November 1991 and February 1993 who survived > 48 hours and who were matched with the VCF group for mechanism of injury and risk factors for PE (NO VCF group). MEASUREMENTS AND MAIN RESULTS VCF placement affected a significant reduction in the incidence of PE (2.5% vs. 17%) and a clinical reduction in PE-related mortality. Embolic trapping was suggested by a 10% incidence of documented vena caval thrombi and although two patients developed significant venous stasis disease, no other VCF-related morbidity was noted. CONCLUSIONS In spite of long-term morbidity, early prophylactic VCF placement is safe and should be considered in the prophylaxis of PE in the high-risk injured patients. This intervention may be effective in eliminating PE as a major cause of posttrauma morbidity and mortality.

Results of a multicenter study of the modified hook-titanium Greenfield filter

Initial efforts to modify the stainless steel Greenfield filter for percutaneous insertion led to development of a titanium Greenfield filter, which could be inserted by use of a 12F carrier. This device functioned well as a filter but had an unacceptable 30% rate of migration, tilting, and penetration. Therefore a titanium Greenfield filter with modified hooks was developed and has been tested in 186 patients at 10 institutions. Successful placement occurred in 181 (97%); placement of the remainder was precluded by unfavorable anatomy. A contraindication to anticoagulation was the most frequent indication for insertion (75%). All but two were inserted percutaneously, predominantly via the right femoral vein (70%). Initial incomplete opening was seen in four patients (2%), which was corrected by guide wire manipulation and asymmetry of the legs in 10 (5.4%). Insertion site hematoma occurred in one patient, and apical penetration of the cava during insertion occurred in a second patient. Both events were without sequelae. Follow-up examinations were performed at 30 days at which time 35 deaths had occurred. Recurrent embolism was suspected in six patients (3%) and two of three deaths were confirmed by autopsy. Filter movement greater than 9 mm was seen in 13 patients, (11%) and increase in base diameter greater than or equal to 5 mm was seen in 17 patients (14%). CT scanning showed evidence of caval penetration in only one patient (0.8%). Insertion site venous thrombosis was seen in 4/46 (8.7%) patients screened. The modified hook titanium Greenfield filter is inserted percutaneously or operatively through a sheath, eliminating concern for misplacement from premature discharge.(ABSTRACT TRUNCATED AT 250 WORDS)

Posttrauma thromboembolism prophylaxis.

PURPOSE The need to study methods of thromboembolism prophylaxis in high-risk trauma patients is well established. The purpose of this study was to evaluate the feasibility of a proposed study design, including current methods of prophylaxis, performance of a risk assessment profile scale, and the use of serial color-flow duplex studies in detecting deep venous thrombosis (DVT). METHODS Patients were enrolled into the study, stratified as to their ability to receive anticoagulation and randomized to low-dose unfractionated heparin, low molecular weight heparin, pneumatic compression devices, or foot pumps with or without vena caval filters. Serial ultrasound scans were performed at designated intervals for 4 weeks. Pulmonary angiograms were obtained for clinical signs or symptoms of pulmonary embolism. RESULTS Fifty-three patients, 32 male and 21 female patients with a mean age of 44 years, completed the study. The incidence of DVT was 43% (23 of 53 patients) and significantly higher in older patients. There were no pulmonary embolisms. Color-flow duplex proved to be a sensitive method for detecting both proximal and distal thrombi. The risk assessment profile for thromboembolism (RAPT) scale identified a group of patients with a high incidence of DVT. However, the occurrence of DVT was not correlated with the magnitude of the RAPT score. CONCLUSION The ability to identify a population with a high incidence of thromboembolism by using the RAPT score to detect asymptomatic DVT, and the suggested advantage of low molecular weight heparin, all support the need for an appropriately powered randomized clinical trial.

Long-term experience with transvenous catheter pulmonary embolectomy

PURPOSE Massive pulmonary embolism (PE), defined by systemic hypotension and need for inotropic support, has a high mortality rate. Transvenous catheter pulmonary embolectomy performed with the patient receiving local anesthetic provides an expeditious alternative to lytic therapy or open embolectomy on cardiopulmonary bypass. METHODS The indication for embolectomy in this series of 46 patients was hypotension despite inotropic support in all but four patients (91%); the latter sustained major embolism and were respirator dependent. In the first 10 patients treated from 1970 to 1974, a metal cup attached to a straight catheter was used. RESULTS Hemodynamic improvement occurred in nine of 10 initial patients, but recurrent PE and a mortality rate of 50% prompted addition of a vena caval filter and directional control to the catheter. Subsequently 36 patients were treated with this combination from 1975 to 1992. Emboli were extracted in 76% (35 of 46) of the total series with a 30-day survival rate of 70% (32 of 46). Hemodynamic data showed an average reduction in mean pulmonary artery pressure of 8 mm Hg and a significant increase in mean cardiac output from 2.59 L/min to 4.47 L/min (p = 0.003) after embolectomy. Complications included wound hematoma (15%), pulmonary infarct (11%), recurrent deep venous thrombosis (6%), pleural effusion (4%), and myocardial infarction (4%). CONCLUSIONS Successful embolectomy was most likely for categories of major PE (4 of 4, 100%) and massive PE (27 of 33, 82%) and least likely for chronic PE (5 of 9, 56%) (p < 0.03). Successful embolectomy also predicted long-term survival (p < 0.01), which was 89 months for the series (range 1 to 237 months). Catheter pulmonary embolectomy by surgeon and radiologist is of maximal benefit for major or massive PE but less likely to benefit patients with chronic recurrent PE.

A National and Single Institutional Experience in the Contemporary Treatment of Acute Lower Extremity Ischemia

Objective To determine the contemporary clinical relevance of acute lower extremity ischemia and the factors associated with amputation and in-hospital mortality. Summary Background Data Acute lower extremity ischemia is considered limb- and life-threatening and usually requires therapy within 24 hours. The equivalency of thrombolytic therapy and surgery for the treatment of subacute limb ischemia up to 14 days duration is accepted fact. However, little information exists with regards to the long-term clinical course and therapeutic outcomes in these patients. Methods Two databases formed the basis for this study. The first was the National Inpatient Sample (NIS) from 1992 to 2000 of all patients (N = 23,268) with a primary discharge diagnosis of acute embolism and thrombosis of the lower extremities. The second was a retrospective University of Michigan experience from 1995 to 2002 of matched ICD-9-CM coded patients (N = 105). Demographic factors, atherosclerotic risk factors, the need for amputation, and in-hospital mortality were assessed by univariate and multivariate logistic regression analysis. Results In the NIS, the mean patient age was 71 years, and 54% were female. The average length of stay (LOS) was 9.4 days, and inflation-adjusted cost per admission was

Suprarenal filter placement

25,916. The amputation rate was 12.7%, and mortality was 9%. Decreased amputation rates accompanied: female sex (0.90, 0.81–0.99), age less than 63 years (0.47, 0.41–0.54), angioplasty (0.46, 0.38–0.55), and embolectomy (0.39, 0.35–0.44). Decreased mortality accompanied: angioplasty (0.79, 0.64–0.96), heparin administration (0.50, 0.29–0.86), and age less than 63 years(0.27, 0.23–0.33). The University of Michigan patients’ mean age was 62 years, and 57% were men. The LOS was 11 days, with a 14% amputation rate and a mortality of 12%. Prior vascular bypasses existed in 23% of patients, and heparin use was documented in 16%. Embolectomy was associated with decreased amputation rates (0.054, 0.01–0.27) and mortality (0.07, 0.01–0.57). Conclusions In patients with acute limb ischemia, the more widespread use of heparin anticoagulation and, in select patients, performance of embolectomy rather than pursuing thrombolysis may improve patient outcomes.

Osteomyelitis of the Foot and Toe in Adults Is a Surgical Disease: Conservative Management Worsens Lower Extremity Salvage

PURPOSE This study was undertaken to determine the clinical outcomes for patients with Greenfield filters placed in the suprarenal (SR) inferior vena cava (IVC). METHODS We collected data prospectively from annual follow-up evaluations of patients with filters. Patients underwent venous color-flow duplex examinations of the IVC and lower extremities, abdominal radiographs, and physical assessment. The outcomes for those patients with filters in the SR IVC were compared with the outcomes previously reported and with the outcomes for patients with filters in the infrarenal cava. RESULTS SR placement accounted for 7.6% (148/1932) of all filter placements. Follow-up data were available for 73 placements, or 49%. No cases of renal dysfunction were related to filter placement. The rate of recurrent pulmonary embolism (PE) was 8%, and the rate of long-term caval occlusion was 2.7%. These rates did not differ statistically from the rates for patients with infrarenal filters (P > .05). Male patients tended to be older by 15 years, to have more recurrent PE, and to experience more filter migration (6 vs 2 mm). Failure of SR filters to prevent PE was associated statistically with the primary indication for placement. Recurrent PE was the indication in 5 of 6 patients who sustained PE after SR filter placement (P = .007). Filter limb fracture was seen only with the stainless-steel Greenfield filter. CONCLUSION Greenfield filters placed above the renal vein provide protection from PE with a minimal risk of occlusion. Twenty-five years of experience with Greenfield filters shows that they are safe and effective both in young female patients of child-bearing potential and in all patients with appropriate indications for SR placement.

Extended evaluation of the titanium Greenfield vena caval filter

Objective:To characterize the national epidemiology of adult osteomyelitis (OM) and, using a single institutions’ experience, test the hypothesis that early surgical therapy as compared with antibiotics alone results in an improved chance of wound healing and limb salvage. Background:Foot and digit OM is a very common problem for which management is variable and for which few guidelines exist. Methods:The Nationwide Inpatient Sample (NIS) and a single institution review from 1993 to 2000 form the basis of this study, using ICD-9CM codes for lower extremity foot and digit OM. Demographics, risk factors, and treatments were analyzed against the outcomes of a healed wound, limb salvage, and death. Results:The NIS included 51,875 patients (incidence = 9/10,000 patients per year) with a mean age of 60 years, and 59% were men. The median length of stay decreased from 9 to 6 days (P < 0.001), but the average admission charge of

Experimental embolic capture by asymmetric Greenfield filters

19,000 did not significantly decrease over 7 years. Of these patients, 23% underwent a digit amputation and 8.5% suffered proximal limb loss. Single-institution analysis of 237 consecutive patients with OM confirmed a similar mean age (58 years), gender (67% men), and most presented with a foot or digit ulcer (56%). Wound healing was achieved in 56% and overall limb salvage was 80%. Decreased wound healing was associated with peripheral vascular occlusive disease (odds ratio, 0.4; 95% confidence interval, 0.2–0.8, P = 0.006) and preadmission antibiotic use (odds ratio, 0.2; 95% confidence interval, 0.05–1.1, P=0.07), while surgical debridement (odds ratio, 2.2; 95% confidence interval, 1.2–4.2, P = 0.02) was associated with increased healing. Limb salvage was improved with an arterial bypass (odds ratio, 3.9; 95% confidence interval, 1.1–14, P = 0.04), while preadmission solid organ transplant (odds ratio, 0.37; 95% confidence interval, 0.14–0.96, P = 0.04), peripheral vascular occlusive disease (odds ratio, 0.25; 95% confidence interval, 0.12–0.5, P = 0.001), and preadmission antibiotic use (odds ratio, 0.34; 95% confidence interval, 0.15–0.77, P = 0.009) were associated with greater limb loss. Conclusion:Digit OM is an expensive and morbid disease. Aggressive surgical debridement/digit amputation and selected use of arterial bypass should improve wound healing and limb salvage, respectively. In contrast, antibiotic therapy alone is associated with decreased wound healing and limb salvage.