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Biomedical subjects

A H Cragg

Publications and source records attributed to A H Cragg.

At least 19 recordsLinked to original sources
PubMed2000

Safety of short stay observation after peripheral vascular intervention.

PURPOSE: To determine whether short observation periods (less than or equal to 4 hours) are safe in outpatients undergoing arterial peripheral vascular interventions. MATERIALS AND METHODS: A retrospective review of 203 patient medical records from the Interventional Vascular Department for 239 lower extremity or abdominal procedures (161 men and 78 women) during a 5-year period was completed. The average patient age was 62.2 years (range, 32-83 years). Thirty-six patients had more than one procedure. Indication, intervention, coagulation status, complication rate, and hospitalizations within 7 days after discharge from the short stay unit (SSU) were reviewed and the outcome was measured. Patients were grouped according to the length of their observation period (< or =4 hours or >4 hours) for statistical analysis. RESULTS: In 85% of the procedures (204 procedures), claudication was the primary indication for intervention. Angioplasty (203 procedures) was also commonly performed. Ninety procedures (38%) required stent placement, and other interventional procedures performed were pulse-spray thrombolysis (eight procedures), atherectomy (two procedures), and stent-graft placement (one procedure). None of the patients required hospitalization as a result of their radiologic intervention within 7 days after discharge from the SSU. Specifically, there were no major "at home" complications in patients discharged after an observation period of < or =4 hours. Two patients were admitted for outpatient procedures and were subsequently hospitalized as a result of a complication from the procedure. The complication rate (including minor complications) was 8% (seven of 87) in the < or =4 hour observation period group compared with 24.3% (37 of 152) in the >4 hour group (P < .01). This difference was due to a greater number of minor hematomas in the >4 hour group. CONCLUSION: Based on the authors' findings, many interventional vascular procedures can be performed safely on an outpatient basis with relatively short observation times. Early discharge from the SSU did not result in an increased readmission rate to the hospital because of delayed complications.

Abdomen↗
PubMed2000

New hemodynamic test for assessment of failing hemodialysis grafts: the saline infusion test.

PURPOSE: To validate the saline infusion test, a new hemodynamic test for assessment of failing hemodialysis access grafts. MATERIALS AND METHODS: Over a 12-month period, 31 procedures were performed in 25 patients with synthetic forearm loop grafts for hemodialysis. Pre- and postangioplasty measurements of static graft pressures and infusion pressures were obtained. For the saline infusion test, graft pressure was measured while saline was infused at a rate of 600 mL/min for 10 seconds with arterial inflow occluded. Comparison was made to percent outflow stenosis as determined with pre- and postangioplasty angiograms. RESULTS: There was no correlation between either the static intragraft pressure (r = .085, P = .654) or the normalized pressure ratio (r = .136, P = .4676) and venous outflow stenosis in the preangioplasty group. When pressure was measured during infusion, a significant Pearson correlation was observed between infusion pressure and percent of angiographic stenosis (r = .60, P = .0002). All three pressure tests were significantly correlated to the percent stenosis identified after angioplasty. CONCLUSIONS: Pressure measured in the graft during the saline infusion test at a standard rate that simulates optimal graft flow correlates with the angiographic degree of stenosis and warrants further investigation as a useful adjunct to the assessment of revascularization results.

Aged↗
PubMed1999

Synthetic dialysis shunts: thrombolysis with the Cragg thrombolytic brush catheter.

PURPOSE: To evaluate the effectiveness of the Cragg thrombolytic brush catheter for declotting of synthetic arteriovenous dialysis shunts. MATERIALS AND METHODS: In this randomized controlled trial, 77 patients with synthetic forearm loop shunts that were thrombosed were randomly assigned to undergo pharmacomechanical thrombolysis with a pulsed spray (n = 34) or a thrombolytic brush catheter (n = 43). The following findings were evaluated: declotting time, urokinase dose, procedure time, complications, and shunt patency at the first dialysis session and at 3 months. All data were collected prospectively in an unblinded manner. RESULTS: The total amount of urokinase used, including secondary interventions, was 243,657 IU with the catheter versus 476,563 IU with the pulsed spray (P = .001). At 15 minutes, clot lysis was successful in 66% of the patients with the catheter versus in 19% with the pulsed spray (P = .001). At 30 minutes, clot lysis was successful in 98% with the catheter versus 47% with the pulsed spray (P = .001). Procedure complication rates and patency at 3 months were similar for the catheter and the pulsed-spray groups. CONCLUSION: Use of the Cragg catheter with urokinase offered faster and more complete clot lysis than did use of the pulsed spray with urokinase. The amount of urokinase used with the catheter was half that used with the pulsed spray. Shunt patency at 3 months was similar for the two treatment methods.

Arteriovenous Shunt, Surgical↗
PubMed1996

Abdominal aortic aneurysms: preliminary technical and clinical results with transfemoral placement of endovascular self-expanding stent-grafts.

PURPOSE: To evaluate treatment of infrarenal abdominal aortic aneurysm (AAA) with a new endoluminal stent-graft. MATERIALS AND METHODS: In 26 male patients, straight or bifurcated nitinol stents covered with woven Dacron graft material were implanted to treat eccentric saccular AAA (n = 3) or AAA involving the bifurcation and common iliac arteries (n = 23), with follow-up from 8 days to 8 1/2 months. RESULTS: Implantation was technically successful in all but one of the 26 (96%) patients (leak of the stent-graft for more than 3 months necessitated implantation of an additional covered stent). In seven of the 26 patients, minor residual perfusion persisted immediately after implantation, but complete thrombosis occurred within 7 days. Five procedure-related complications occurred: distal embolization (n = 2); local hematoma, which necessitated surgery (n = 1); acute hepatic failure due to gastric bleeding, in a patient with liver cirrhosis (n = 1); and stent-graft occlusion due to emboli originating from the left atrium (n = 1). CONCLUSION: Exclusion of AAA from circulation was feasible, safe, and clinically effective with the new stent-graft.

Aged↗
PubMed1994

Iliac artery stent placement: clinical experience with a nitinol stent.

PURPOSE: To determine the effectiveness of a prototype nitinol stent in the iliac arteries. MATERIALS AND METHODS: Fourteen patients with arteriosclerotic lesions of the iliac arteries (nine stenoses, five occlusions) were treated percutaneously with a prototype nitinol vascular stent (Cragg stent) after unsuccessful percutaneous transluminal angioplasty. RESULTS: In 13 patients available for follow-up, the mean ankle-brachial index (ABI) increased from 0.4 +/- 0.32 (standard deviation) before the procedure to 0.81 +/- 0.27 after the procedure (P < .01). After 6, 12, and 24 months, the mean ABI was 0.97 +/- 0.2, 0.87 +/- 0.15, and 0.89 +/- 0.1, respectively. In two patients, radial stiffness of the stent was too low to completely eliminate a high-grade, calcified stenosis; long-term patency of the vessel, however, was preserved. In all other patients, stent placement achieved good vascular reconstitution. No stent occlusion or restenosis was observed. CONCLUSION: The results with the Cragg stent were similar to those with other commercially available stents. These preliminary results require confirmation with a larger series.

Aged↗
PubMed1993

Percutaneous femoropopliteal graft placement.

Femoropopliteal bypass surgery is now recommended for the treatment of long-segment or diffuse superficial femoral artery disease. The authors describe a technique for percutaneous placement of a prosthetic femoropopliteal graft. The technique has been accomplished with conventional polytetrafluoroethylene graft material and a variety of implantation techniques. Technical success was achieved in eight patients who underwent graft placement. Grafts up to 28 cm in length were placed, and graft patency was demonstrated up to 6 months after implantation. Six of the eight patients were asymptomatic during the follow-up period; one patient who had symptoms during this time underwent thrombolysis and redilation of the distal stent, and the symptoms resolved. This study demonstrates the feasibility of percutaneous graft placement in the femoral artery, but durability must be established in relation to traditional bypass surgery before it can be recommended on a wider scale.

Aged↗
PubMed1993

Nitinol intravascular stent: results of preclinical evaluation.

PURPOSE: To test an expandable nitinol intraluminal stent for hoop strength, biocompatibility, corrosion resistance, and patency. MATERIALS AND METHODS: Forty-four stents were implanted in the iliac arteries of 22 sheep. Follow-up was performed with angiography and histologic examination for up to 6 months. RESULTS: All but one stent remained widely patent during the follow-up period. Two stents in two sheep were placed incorrectly early in the study; these sheep were not followed up. Hoop strength was found to be superior to that of a similar, commercially available, self-expanding stent. Minimal corrosion was seen at 6 months, and the stent appears to be biocompatible. The stent has good radiopacity and deploys with minimal foreshortening. CONCLUSION: The stent can be reliably and safely deployed in the vascular system. Clinical trials in humans are warranted.

Alloys↗
PubMed1992

Management of infrainguinal occluded vein bypasses with a combined approach of thrombolysis and surveillance. A prospective study.

Intra-arterial thrombolysis with urokinase was attempted on 23 occluded infrainguinal vein bypasses. Lesions revealed by thrombolysis included 11 anastomotic stenoses, five midbypass stenoses, five native artery stenoses, and five unusable diffusely stenotic vein conduits. Adjunctive procedures performed immediately after successful thrombolysis included 10 local surgical revisions, five balloon angioplasties, and five new vein bypasses. Three nonanastomotic vein bypass stenoses and two common iliac artery stenoses were detected using a surveillance protocol in subsequent follow-up of patients with patent bypasses. Twelve-month patency following thrombolysis (including immediate failures) was 52.4%. The use of thrombolysis in the management of occluded vein bypasses allows the identification and correction of pathological lesions. Once revised, continued vein bypass patency may be improved with a surveillance program.

Angioplasty, Balloon↗
PubMed1992

Effect of antineoplastic agents on smooth muscle cell proliferation in vitro: implications for prevention of restenosis after transluminal angioplasty.

The effect of several antineoplastic agents on vascular smooth muscle cell proliferation was studied in vitro. Both fluorouracil and cytarabine produced significant concentration-dependent inhibition of smooth muscle cell proliferation in cultured porcine pulmonary artery in vitro, while cyclophosphamide stimulated growth. For fluorouracil, inhibition was near maximal at a concentration of 13.0 microgram/mL and was seen with both coincubation and 2-hour preincubation of fluorouracil with quiescent cells. Fluorouracil is a promising agent for inhibition of intimal proliferation. Further work is warranted to determine its effect in vivo.

Angioplasty, Balloon↗
PubMed1992

Comparison of the efficacy of digital subtraction and film-screen angiography of the lower limb: prospective study in 50 patients.

We prospectively compared current digital subtraction angiography (DSA) with conventional film-screen angiography (FSA) of the lower limb for evaluation of areas of arterial stenosis and degree of arterial visualization. Fifty patients had both DSA and FSA of a single lower limb. Specific anatomic sites (examiner-selected sites) throughout the lower limb were marked on each film by an experienced angiographer (examiner). These sites consisted of the common femoral, superficial femoral, popliteal, anterior tibial, posterior tibial, peroneal, and dorsalis pedis arteries and bypass grafts, when present. The films were then reviewed blindly by two different experienced angiographers (observers). All sites were graded for the degree of arterial narrowing based on a standard scale (grade 1 = normal, grade 5 = occluded) that also included grading for nonvisualization (grade 6). Each observer also selected the most stenotic site in each anatomic area (observer-selected sites). The data were analyzed for the entire lower limb and at specific anatomic sites. DSA sites were judged to be slightly more narrowed (p less than .05) in the superficial femoral artery by both observers and in the common femoral artery, bypass graft, and overall by a single observer. No other significant differences were found in grade of stenosis or vessel visualization for examiner-selected sites. For observer-selected sites, observers agreed on the location of the most stenotic site 76% of the time for FSA and 69% of the time for DSA. No significant difference was found in grade of stenosis or vessel visualization for either observer for the entire lower limb or at specific anatomic sites. These findings were present when all sites chosen were considered and when there was agreement between sites chosen on FSA and DSA for each observer. In conclusion, optimal-quality FSA and DSA produced virtually equivalent results for angiography of the lower limb for both grade of stenosis/occlusion and vessel visualization.

Angiography↗
PubMed1991

Hematoma formation after diagnostic angiography: effect of catheter size.

The authors studied the effect of catheter size on the development of hematomas after catheterization. Four hundred ninety-nine patients who underwent routine diagnostic angiography were randomized to receive either 5-F or 7-F catheters. Small hematomas were more frequent in the 7-F catheter group (P less than .05); however, there was no difference in the frequency of larger hematomas between groups. Compression time was slightly but significantly (P less than .001) longer in the 7-F group. When catheter size; duration of the procedure; and patient age, weight, blood pressure and coagulation status were considered as independent variables, patient weight was the most accurate predictor of hematoma formation. The authors conclude that catheter size does not affect the development of a clinically significant hematoma after diagnostic angiography and that other factors such as patient weight are more important in this regard.

Angiography↗
PubMed1991

Time course of satisfaction of search.

"Satisfaction of search" (SOS) refers to the effect in which a second lesion remains undetected after detection of another lesion on the same radiograph. The objective of this study was to clarify our understanding of SOS by relating it to total time of inspection and time intervals before, between, and after discovery of lesions. Detection accuracy of native lesions in chest radiographs, before and after the addition of a simulated nodular lesion, was measured for ten observers. Analysis of data from this and a previous experiment showed that average perceptual accuracy of individual receiver operating characteristic curves was significantly reduced with the addition of the nodules. Plots and analyses of search time revealed that, on average, during a typical 46-second inspection of a case, simulated nodules were found at 18 seconds, native abnormalities at 25 seconds, and false positives occurred at 33 seconds. Time needed to find nodules did not depend on whether native lesions were present; time to find native lesions did not change with addition of nodules; and total search time was the same for images with one, two, or no lesions. The detection results show that the SOS effect was obtained, but that interrupting search in order to measure it also diminishes accuracy. Analysis of the time course data relates SOS to perceptual capture and strategic halting of search.

Diagnostic Errors↗
PubMed1991

Two urokinase dose regimens in native arterial and graft occlusions: initial results of a prospective, randomized clinical trial.

The effects of two urokinase (UK) dose regimens on lysis time, lytic success, primary clinical success, and frequency of complications of peripheral thrombolysis were compared. Seventy-two intraarterial UK infusions were performed by means of standard catheter-directed infusion techniques in 63 patients with symptomatic peripheral arterial or bypass graft occlusions. Patients were prospectively randomized to high-dose (250,000 U/h for 4 hours and then 125,000 U/h) or low-dose (50,000 U/h) regimens. The mean time to complete lysis was 20.8, 26.0, 16.5, and 18.2 hours for the high-dose artery, low-dose artery, high-dose graft, and low-dose graft groups, respectively (P was not significant). Respective mean infusion durations were 27.1, 35.4, 22.2, and 25.3 hours. Clinical success was achieved in 65%-85% of cases. The frequency of complications was equivalent between groups, except for a higher frequency of minor bleeding complications in the high-dose group. The two urokinase dose regimens studied were equally effective in enabling peripheral thrombolysis.

Angiography↗
PubMed1991

Nephrotoxicity from contrast material in renal insufficiency: ionic versus nonionic agents.

Controversy exists over whether use of low-osmolality contrast agents is of any benefit in mitigating the risk of contrast material-induced nephrotoxicity (CN) in patients with impaired renal function. To test this hypothesis, 101 adult inpatients with high serum creatinine levels (range, 1.4-2.4 mg/dL [120-210 mumol/L]) undergoing contrast material-enhanced computed tomography were randomized to receive ionic or nonionic (low-osmolality) contrast agents in a uniform dose. Changes in serum creatinine level at 48 hours were measured. Seven (14%) of the 50 patients receiving ionic contrast media experienced an increase of 25% or more in serum creatinine level. Only one (2%) of the 51 patients receiving nonionic contrast agents experienced such an increase, a statistically significant difference (P less than .05). In the subset of 25 diabetic patients, the difference was of a similar magnitude. These data suggest that ionic contrast media are more likely than nonionic contrast agents to cause mild exacerbation of renal insufficiency when given intravenously. However, there were no cases of clinically important CN in the study.

Adult↗
PubMed1991

Randomized double-blind trial of midazolam/placebo and midazolam/fentanyl for sedation and analgesia in lower-extremity angiography.

Safety and efficacy of two drug regimens used for sedation and analgesia during lower-extremity angiography were studied. Midazolam (loading dose 14.5 micrograms/kg; maintenance dose, 7.2 micrograms/kg) with or without fentanyl (loading dose, 0.725 micrograms/kg; maintenance dose, 0.362 micrograms/kg) was administered in a blind fashion as an IV bolus to 50 patients. Hemodynamic responses were monitored, and a standardized questionnaire was given to the patient before, immediately after, and 8-24 hr after the procedure. Physicians also were asked questions after the procedure. Heart rate and oxygen saturation were not significantly different before and 2 min after administration or between groups. A small but significant decrease in blood pressure occurred 2 min after the loading dose was given in both groups. Both drug regimens had statistically significant anxiolytic effects; however, anxiolytic effects were superior in the midazolam/fentanyl group (p less than .02). Patients rated the overall effectiveness of anesthesia with midazolam/fentanyl as superior (p less than .02). Analysis of physicians' judgments of the effectiveness of sedation and analgesia showed a statistically significant advantage for the midazolam/fentanyl group (p less than .01). We conclude that midazolam/fentanyl appears to be as safe as and more efficacious than midazolam alone for sedation and analgesia during lower-extremity angiography.

Angiography↗