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Biomedical subjects

Harry L Bush

Publications and source records attributed to Harry L Bush.

16 recordsLinked to original sources
PubMed2006

Analysis of outcomes following failed endovascular treatment of chronic limb ischemia.

Despite recent studies highlighting the advantages of endoluminal intervention in the management of chronic limb ischemia (CLI), outcomes following failed peripheral angioplasty remain less well described. We present a retrospective analysis of failed transluminal infrainguinal percutaneous arterial angioplasty with or without stenting (PTA/S) in patients with CLI. A database of patients undergoing infrainguinal PTA/S between 2002 and 2005 was maintained. Patients underwent duplex scanning follow-up at 2 weeks, 3 months, and every 6 months after the intervention. Angiograms were reviewed in all cases to assess lesion characteristics. Results were standardized to current Transatlantic Inter-Society Consensus (TASC) criteria. Kaplan-Meier survival analyses were performed to assess time-dependent outcomes. In total, our analysis involved 246 patients who underwent treatment for CLI using PTA/S. Eighteen percent of procedures (n = 46) were considered an intervention failure secondary to restenosis by duplex ultrasound, returning clinical symptoms, a nonhealing foot lesion, or the absence of a prior palpable pulse. Indications for the original procedure in patients whose PTA/S failed were tissue loss in 44%, claudication in 44%, and rest pain in 12%, while TASC lesion grades were A (0%), B (18%), C (18%), and D (64%). Of patients failing PTA/S, 4% failed in the first 30 days, 78% failed between 1 and 18 months, while 18% failed following 18 months, with a mean time to failure of 8.7 months. Also, 82% of PTA/S failures were candidates for a second endovascular procedure, 11% were suitable for only traditional open bypass, and 4% demonstrated progression of disease necessitating amputation. Of patients undergoing a second endovascular procedure, limb salvage rates were 86% at 12-month follow-up and there was a single periprocedural mortality and complication rate of 6.6%. Of patients requiring open surgical bypass after failed PTA/S, 20% (n = 1) required a major amputation and there were no mortalities. Failure of endoluminal therapy for treatment of lower extremity arterial occlusive disease is amenable to subsequent endovascular intervention for limb salvage with limited morbidity and mortality.

Adult↗
PubMed2006

Simulation improves resident performance in catheter-based intervention: results of a randomized, controlled study.

OBJECTIVES: Surgical simulation has been shown to enhance the training of general surgery residents. Since catheter-based techniques have become an important part of the vascular surgeon's armamentarium, we explored whether simulation might impact the acquisition of catheter skills by surgical residents. METHODS: Twenty general surgery residents received didactic training in the techniques of catheter intervention. Residents were then randomized with 10 receiving additional training with the Procedicus, computer-based, haptic simulator. All 20 residents then participated in 2 consecutive mentored catheter-based interventions for lower extremity occlusive disease in an OR/angiography suite. Resident performance was graded by attending surgeons blinded to the resident's training status, using 18 procedural steps as well as a global rating scale. RESULTS: There were no differences between the 2 resident groups with regard to demographics or scores on a visuospatial test administered at study outset. Overall, residents exposed to simulation scored higher than controls during the first angio/OR intervention: procedural steps (simulation/control) (50 +/- 6 vs. 33 +/- 9, P = 0.0015); global rating scale (30 +/- 7 vs. 19 +/- 5, P = 0.0052). The advantage provided by simulator training persisted with the second intervention (53 +/- 6 vs. 36 +/- 7, P = 0.0006); global rating scale (33 +/- 6 vs. 21 +/- 6, P = 0.0015). Moreover, simulation training, particularly for the second intervention, led to enhancement in almost all of the individual measures of performance. CONCLUSION: Simulation is a valid tool for instructing surgical residents and fellows in basic endovascular techniques and should be incorporated into surgical training programs. Moreover, simulators may also benefit the large number of vascular surgeons who seek retraining in catheter-based intervention.

Angiography↗
PubMed2006

Safety and efficacy of carotid angioplasty and stenting in high-risk patients.

Performance of carotid endarterectomy (CEA) may be associated with an increased risk in patients with significant comorbid medical conditions, neck irradiation, or previous CEA. This study compared the results of CEA with carotid angioplasty and stenting (CAS) in high-risk patients treated for carotid stenosis. Five hundred forty-five patients who underwent CEA and 148 patients who underwent CAS were evaluated. For patients undergoing CEA, general anesthesia was used in 91 per cent, electroencephalographic monitoring was used in 63 per cent, and shunting was performed in 19.8 per cent. Cerebral protection devices were used in 145/148 of CAS cases, and self-expanding stents were used in all cases. Evaluated end points included major cardiovascular events, and a composite of death, stroke, or myocardial infarction for the duration of the follow-up. Mean follow-up was 18 months for CAS and 23 months for CEA. Significant differences were present in patient age (CAS, 75 +/- 11.0 years vs CEA, 71 +/- 9 years, P = 0.012), however, there were no significant differences (P = NS) in gender or smoking history. The mean modified Goldman Score was significantly higher for CAS (21.1 +/- 14.8 [95% confidence interval = 18, 24]) than for CEA (6.3 +/- 6.8 [95% confidence interval = 5.7, 6.9]; P = 0.0001) patients. The incidence of periprocedural complications did not vary significantly between patients treated with CAS (CVA, 1.4%; myocardial infarction [MI], 1.4%; death, 0.7%; CVA/MI/death, 3.4%) compared with CEA (CVA, 1.8%; MI, 1.1%; death, 0.4%; CVA/MI/death, 4.0%). CAS is equivalent to CEA in safety and efficacy, even when performed in patients who may be at increased surgical risk.

Age Factors↗
PubMed2005

Comparison of results in endovascular interventions for infrainguinal lesions: claudication versus critical limb ischemia.

This study analyzed clinical success, patency, and limb salvage after endovascular repair in patients treated for chronic limb ischemia presenting with claudication versus critical limb ischemia. Between October 2001 and August 2004, 115 patients (mean age 71) underwent endovascular treatment for infrainguinal arterial disease. Techniques included subintimal angioplasty and transluminal angioplasty with or without stents. Lesions were classified according to Transatlantic InterSociety Consensus. Follow-up (mean 11 months) included physical exam, ankle-brachial index, and duplex ultrasound. Patency rates were determined using Kaplan-Meier and compared by log-rank analysis. One hundred ninety-nine lesions were treated in 121 limbs using percutaneous techniques. Comorbidities were similar except higher rates of diabetes mellitus (67% vs 41%, P < 0.001) and chronic renal insufficiency (22% vs 7%, P < 0.05) were found in critical limb ischemia patients. Primary patency for claudicants was 100 per cent, 98 per cent, and 85 per cent at 3, 6, and 12 months and 89 per cent, 80 per cent, and 72 per cent for critical limb ischemia, respectively (P = 0.06). Limb salvage was 91 per cent at 12 months for critical limb ischemia patients. Morbidity was similar between groups, and there was no perioperative mortality. Percutaneous intervention for both claudication and critical limb ischemia provides acceptable 12 month patency with limited morbidity.

Adult↗
PubMed2004

Soft tissue enhancement on time-resolved peripheral magnetic resonance angiography.

PURPOSE: To evaluate the incidence and locations of soft tissue enhancement on time-resolved two-dimensional projection magnetic resonance angiography (MRA) of the calf and foot. MATERIALS AND METHODS: Time-resolved two-dimensional projection MRA of the knee, calf, and foot, performed at 1.5 Tesla using the head coil, was retrospectively reviewed in 326 patients. Soft tissue enhancement of the foot was identified and graded by blinded review. Subsequently, patient medical records were reviewed to determine the presence or absence of diabetes, cellulitis, gangrene, and ulceration of the foot and presence of neuropathic joints. RESULTS: Enhancing spots were identified in 228 patients. For those feet without clinical abnormalities, diabetic patients had an average of 1.2 enhancing spots per foot, while nondiabetics had only 0.6 (P < 0.001). Higher-grade lesions were more prevalent in diabetics and in heavier patients. Of 64 patients with follow-up, 8 (13%) developed cellulitis (N = 4) or ulceration (N = 4) at the location of an enhancing spot, including 5 diabetic and 3 nondiabetic patients. CONCLUSION: Pedal soft tissue enhancement frequently occurs on time-resolved gadolinium (Gd):MRA of the feet. The etiology is uncertain, but the high frequency in diabetic patients and observation of progression to cellulitis/ulceration suggest this soft tissue enhancement may identify sites of subclinical pedal soft tissue injury.

Adult↗
PubMed2004

Decreased venous contamination on 3D gadolinium-enhanced bolus chase peripheral mr angiography using thigh compression.

OBJECTIVE: We evaluated the potential for improving bolus chase peripheral MR angiography in patients with fast arterial flow using thigh compression to prevent venous contamination. SUBJECTS AND METHODS: We performed bolus chase peripheral MR angiography in 32 consecutive patients in whom the travel time for a contrast agent to reach the popliteal artery trifurcation was less than 25 sec. Thigh compression was applied by a tourniquet (n = 13) or blood pressure cuff inflated to 60 mm Hg (n = 19). We compared the results with those of 36 consecutive patients who underwent angiography without thigh compression. The effect of thigh compression on arterial flow and tissue enhancement was assessed in patients with symmetric travel time in both legs by applying compression to one leg during the time-resolved 2D-projection MR angiography with 6 mL of gadolinium. On 3D bolus chase MR angiography, thigh compression was applied bilaterally. Venous contamination on the 3D images of the calf was graded as 0, none; 1, trace; 2, mild; 3, moderate; and 4, severe. Signal-to-noise ratio was measured in the popliteal artery. RESULTS: Thigh compression slowed the arterial travel time by a mean +/- SD of 4.7 +/- 2 sec (p < 0.001) with a blood pressure cuff and 3.1 +/- 1 sec (p < 0.001) with a tourniquet. Blood pressure cuffs reduced the score of venous contamination on the calf station from 1.9 to 0.4 (p < 0.05) for intermediate flow (contrast travel time, 20-25 sec) and from 2.5 to 0.9 (p < 0.05) for fast flow (< 20 sec). Thigh compression increased the popliteal artery signal-to-noise ratio (81 vs 52, p < 0.001). CONCLUSION: Thigh compression with blood pressure cuffs inflated to 60 mm Hg slows down arterial flow, increases arterial signal-to-noise ratio, and reduces venous contamination on 3D gadolinium-enhanced bolus chase peripheral MR angiography.

Aged↗
PubMed2003

Atherosclerotic disease distribution in carotid and vertebrobasilar arteries: clinical experience in 100 patients undergoing fluoro-triggered 3D Gd-MRA.

PURPOSE: To determine how often three-dimensional gadolinium-enhanced magnetic resonance angiography (3D Gd-MRA) shows disease outside of the standard two-dimensional time-of-flight magnetic resonance angiography (2D TOF-MRA) imaging volume. MATERIALS AND METHODS: One hundred consecutive patients with known or suspected cerebrovascular disease were examined using fluoro-triggered 3D Gd-MRA with a 1.5 Tesla scanner. All vessel segments from the aortic arch to the circle of Willis were independently evaluated for the presence of occlusive disease, ulceration, aneurysm, and anatomic variations by two radiologists blinded to clinical information. Branch vessel and circle of Willis visibility were also assessed. Kappa statistics were calculated to determine interobserver agreement. RESULTS: Interobserver agreement for the degree of stenosis was good to excellent (kappa = 0.83-1.0). Disagreement was more frequent in the cases of mild stenoses and was less frequent for stenoses > or = 50%. In 38% of the patients, 3D Gd-MRA demonstrated either ulcerated plaques in carotid arteries (N = 14) or stenosis > or = 50% in great vessel (N = 20) and/or vertebral artery (N = 38) origins, none of which can be readily evaluated on standard TOF-MRA. CONCLUSION: Fluoro-triggered 3D Gd-MRA provides a comprehensive evaluation of the carotid arteries including all vessel segments from the aortic arch to the circle of Willis.

Adult↗
PubMed2003

Is carotid angioplasty and stenting more cost effective than carotid endarterectomy?

OBJECTIVE: Carotid angioplasty and stenting (CAS) has been advocated as a minimally invasive and inexpensive alternative to carotid endarterectomy (CEA). However, a precise comparative analysis of the immediate and long-term costs associated with these two procedures has not been performed. To accomplish this, a Markov decision analysis model was created to evaluate the relative cost effectiveness of these two interventions. METHODS: Procedural morbidity/mortality rate for CEA and costs (not charges) were derived from a retrospective review of consecutive patients treated at New York Presbyterian Hospital/Cornell (n = 447). Data for CAS were obtained from the literature. We incorporated into this model both the immediate procedural costs and the long-term cost of morbidities, such as stroke (major stroke in the first year = $52,019; in subsequent years = $27,336/y; minor stroke = $9419). We determined long-term survival rate in quality-adjusted life years and lifetime costs for a hypothetic cohort of 70-year-old patients undergoing either CEA or CAS. Our measure of outcome was the cost-effectiveness ratio. RESULTS: The immediate procedural costs of CEA and CAS were $7871 and $10,133 respectively. We assumed major plus minor stroke rates for CEA and CAS of 0.9% and 5%, respectively. We assumed a 30-day mortality rate of 0% for CEA and 1.2% for CAS. In our base case analysis, CEA was cost saving (lifetime savings = $7017/patient; increase in quality-adjusted life years saved = 0.16). Sensitivity analysis revealed major stroke and death rates as the major contributors to this differential in cost effectiveness. Procedural costs were less important, and minor stroke rates were least important. CAS became cost effective only if its major stroke and mortality rates were made equivalent to those of CEA. CONCLUSION: CEA is cost saving compared with CAS. This is related to the higher rate of stroke with CAS and the high cost of stents and protection devices. To be economically competitive, the mortality and major stroke rates of CAS must be at least equivalent if not less than those of CEA.

Aged↗
PubMed2003

Gadodiamide administration causes spurious hypocalcemia.

PURPOSE: To evaluate the prevalence of spurious hypocalcemia after gadodiamide-enhanced magnetic resonance (MR) imaging. MATERIALS AND METHODS: Eight hundred ninety-six inpatients with available serum calcium data obtained before and after gadodiamide-enhanced MR imaging were identified. Changes in serum calcium measurements following gadodiamide administration in 1,049 MR imaging examinations performed in these patients were correlated with gadodiamide dose, renal function, and time between gadodiamide administration and phlebotomy. RESULTS: Following 42 gadodiamide-enhanced examinations, serum calcium measurements spuriously decreased by more than 2 mg/dL (0.5 mmol/L), resulting in laboratory reports of "critical" hypocalcemia (ie, calcium level < 6 mg/dL [1.5 mmol/L]) in 25 examinations. These reduced calcium measurements were correlated with serum creatinine level (r = 0.39, P <.001), gadodiamide dose (r = 0.37, P <.001), and time between gadodiamide injection and phlebotomy (r = -0.28, P <.001). Spurious reductions in calcium measurements after administration of 0.1 mmol of gadodiamide per kilogram of body weight were greater in patients with renal insufficiency (0.6 mg/dL [0.15 mmol/L] +/- 0.5 [0.125, SD]) than in those with normal renal function (0.14 mg/dL [0.035 mmol/L] +/- 0.4 [0.1]) (P <.001). After administration of more than 0.2 mmol/kg of gadodiamide, spurious calcium measurement decreases were greater in patients with renal insufficiency (2.4 mg/dL [0.6 mmol/L] +/- 3.6 [0.9]) than in those with normal renal function (0.4 mg/dL [0.1 mmol/L] +/- 0.7 [0.175]) (P <.001). Patients with renal insufficiency had spuriously low calcium measurements up to 4(1/2) days after gadodiamide administration. Seven patients were inappropriately treated with intravenous calcium and eleven with oral calcium in response to false-positive laboratory reports of critical hypocalcemia. No patient had characteristic symptoms of hypocalcemia or injuries attributed to the inappropriate medical treatment. CONCLUSION: Gadodiamide administration causes spurious hypocalcemia, particularly at doses of 0.2 mmol/kg or higher and in patients with renal insufficiency.

Calcium↗
PubMed2002

Endarterectomy vs stent angioplasty: what is the optimal treatment of carotid stenosis?

Very few operations have been subject to more scientific scrutiny than carotid endarterectomy (CEA). Since its introduction in the 1950s, CEAs have been performed in great numbers with the goal of preventing ischemic stroke. In the mid 1980s concern about over utilization of CEA and reports of excessive perioperative stroke morbidity and mortality prompted the initiation of several multicenter, randomized trials designed to evaluate the efficacy of CEA. As the results of these trials became available, the number and frequency of CEA in the United States increased significantly. However, now a new wave of uncertainty has arisen related to the availability of an alternative to CEA, carotid angioplasty and stent (CAS). Now, more than ever, there is uncertainty as to the proper management of carotid artery stenosis. In this review we summarize the existing data regarding the efficacy of CEA and compare these data to a critical analysis of the recent results of CAS.

Angioplasty↗
PubMed2002

The cost-effectiveness of a "quick-screen" program for abdominal aortic aneurysms.

BACKGROUND: The incidence of abdominal aortic aneurysm (AAA) is increasing, and the prognosis of ruptured AAA remains dismal. Early diagnosis and intervention are crucial. We designed this study to determine whether selected population screening with a brief "quick-screen" ultrasound could be cost-effective. METHODS: A series of 25 patients with risk factors for AAA were evaluated in a blinded fashion by a quick-screen ultrasound and a full conventional study. Times and accuracy for the 2 approaches were compared. An analysis of the cost-effectiveness of screening for AAA was then performed using a Markov model. We determined the long-term survival in quality-adjusted life years and lifetime costs for a hypothetical cohort of 70-year-old males undergoing either AAA screening or not. Our measure of outcome was the cost-effectiveness ratio (CER). RESULTS: The average time for a quick screen was one-sixth that of a conventional study (4 vs 24 minutes). The accuracy of the quick screen was 100%. In our base-case analysis, screening for AAA was cost-effective with a CER of $11,215. Society usually is willing to pay for interventions with CER of less than $60,000 (eg, CER for coronary artery bypass grafting, $9500; breast cancer screening, $16,000). In sensitivity analysis, reducing the cost of screening from $259 (approximate Medicare reimbursement) to $40 (the quick screen) improved the CER to $6850. Moreover, screening populations with increased prevalence of AAA (eg, male with family history [18%]) further improved the CER. CONCLUSIONS: Our analysis demonstrates that ultrasound screening for AAA should be offered to all males above the age of 60. Widespread screening for AAA should be adopted and reimbursed by Medicare and other insurers.

Aged↗
PubMed2002

Why insurers should reimburse for compression stockings in patients with chronic venous stasis.

BACKGROUND: Chronic venous stasis ulcers produce substantial morbidity rates and result in a significant expense to society. Fortunately, compression stockings (CS) have been found to reduce the rate of recurrence in patients with previous ulceration. Surprisingly, Medicare and other insurers do not reimburse the expense associated with CS or with patient education (Ed), which is essential to ensure compliance. METHODS: A Markov decision analysis model was used for analysis of the cost-effectiveness of a strategy of reimbursement for CS and Ed (prophylaxis) versus one that does not supply these resources in a 55-year-old patient with prior venous stasis ulceration. The mean time to ulcer recurrence (53 months with CS+Ed; 18.7 months without prophylaxis), the mean time for ulcer healing (4.6 months), the probabilities of hospitalization (12%) and amputation (0.4%) after the development of an ulcer, and quality-adjustment factors (0.80 during ulcer treatment) were derived from the literature. The cost of CS ($300/year) and Ed ($93 for initial evaluation; $58/year; $40/recurrence) and the medical cost of ulcer treatment (average cost, $1621/recurrence) were calculated from our hospital cost accounting system. RESULTS: A strategy of CS and Ed was cost saving, with 0.37 quality-adjusted life years and $5904 saved, compared with a strategy that does not provide these resources. The inclusion of loss of revenue related to absence from work in the analysis increased cost savings to $17,080 during the patient's lifetime. With sensitivity analysis, CS and Ed remained cost-effective (lifetime cost per quality-adjusted life year saved, <$60,000) if amputations and the cost of ulcer treatment were eliminated or if the cost of prophylaxis was increased to 600% of the base-case. The mean time to recurrence in patients with CS and Ed needed to be reduced from 53 months to 21.1 months before this strategy was no longer cost-effective. CONCLUSION: Prophylactic CS and Ed in patients with prior venous stasis ulceration are cost saving, even with the most conservative of assumptions. Insurers should routinely reimburse for these interventions.

Bandages↗
PubMed2002

Bolus arterial-venous transit in the lower extremity and venous contamination in bolus chase three-dimensional magnetic resonance angiography.

RATIONALE AND OBJECTIVES: To investigate the phenomena and causes for undesired venous signal in the distal station of bolus chase 3D MRA. METHODS: Consecutive patients (in 8 months) undergoing peripheral MRA consisting of 2D projection MRA of the tibial trifurcation and 3D bolus chase MRA were retrospectively evaluated. Venous contamination in mid-calf in bolus chase 3D MRA was correlated to the arterial phase duration, the time between the contrast bolus arrival and venous return measured on time resolved 2D images. Statistical analyses were performed to identify the clinical parameters indicative of venous contamination. RESULTS: The arterial phase durations at the mid-calf were 49 +/- 8 seconds on 101 legs without venous signal in the bolus chase 3D MRA, 35 +/- 9 seconds on 13 legs with moderate venous signal, and 20 +/- 4 seconds on 40 legs with substantial venous signal; the differences were significant among different venous signal levels (P < 0.001 for all pairs). Legs with cellulitis had shorter arterial phase and more venous contamination than legs without cellulitis (P < 0.05). Patients with myocardial infarction had longer arterial phase and less venous contamination than patients without myocardial infarction (P < 0.01). CONCLUSION: Venous signal in the distal calf station of bolus chase 3D peripheral MRA is caused by fast arterial-venous transit. It is worse in legs with cellulitis and less in patients with a history of myocardial infarction.

Aged↗
PubMed2002

Peripheral vascular disease: combined 3D bolus chase and dynamic 2D MR angiography compared with x-ray angiography for treatment planning.

PURPOSE: To compare combined three-dimensional (3D) and two-dimensional (2D) contrast material-enhanced magnetic resonance (MR) angiography with x-ray angiography for planning treatment of peripheral vascular disease. MATERIALS AND METHODS: Three radiologists retrospectively reviewed the pretreatment x-ray angiographic and MR angiographic studies obtained in 30 consecutive patients: 15 patients (15 limbs) evaluated for limb salvage and 15 patients (20 limbs) evaluated because of claudication. MR angiography included acquisition of 2D contrast-enhanced MR digital subtraction angiograms of the area from the adductor canal to the feet and 3D spoiled gradient-recalled-echo bolus chase MR angiograms obtained in three stations from the aorta to the middle portion of the calf. Each reader reviewed the x-ray and MR angiograms to determine the inflow and outflow segments for a hypothetical bypass graft placement. RESULTS: The three readers selected identical segments for inflow at MR angiography and x-ray angiography in 32, 32, and 35 of the 35 limbs evaluated (mean percentages of agreement [95% CI ]: 91% [77%, 98%], 91% [77%, 98%], and 95% [90%, 100%], respectively). The readers selected identical segments for outflow in 32, 32, and 34 of the 35 limbs evaluated (mean percentages of agreement [95% CI]: 91% [77%, 98%], 91% [77%, 98%], and 97% [85%, 100%], respectively). CONCLUSION: Preliminary data support the combining of 2D MR digital subtraction angiography with 3D bolus chase MR angiography to extend the utility of 3D MR angiography in treatment planning to include patients being evaluated for limb salvage, as well as those being evaluated for claudication.

Adult↗