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Biomedical subjects

R T Gregory

Publications and source records attributed to R T Gregory.

At least 19 recordsLinked to original sources
PubMed1994

Vein harvest ischemia: a peripheral vascular complication of coronary artery bypass grafting.

Lower-extremity ischemia can lead to impaired healing of saphenous vein excision sites in patients with significant peripheral vascular disease (PVD). Five patients who required infrainguinal revascularization for wound necrosis of the harvest site after coronary artery bypass grafting are described. The male/female ratio was 2:3 with a mean age of 67 (range 45-87) years. The most commonly associated problems were insulin-dependent diabetes mellitus (80%) and congestive heart failure (60%). The saphenous vein was harvested from the thigh and leg in three patients and exclusively from the leg in the others. Manifestations of ischemia ranged from persistent ulceration to complete wound disruption threatening limb loss. Impaired healing was isolated to infragenicular wounds in all patients. Pedal pulses were not detected in any of the affected extremities. Determination of the ankle/brachial pressure indices (ABI) revealed values of < 0.5 in three affected limbs. Non-compressible vessels resulted in falsely raised ABI of > 1.0 in the remaining two limbs; however, Doppler waveform analysis in these patients demonstrated significant PVD. Aggressive wound care and antibiotic therapy were continued for mean of 9 weeks before operative intervention. Infrainguinal reconstruction included femoropopliteal (two), femorotibial (two) and popliteal-tibial bypass (one). Autologous arm and saphenous veins in addition to expanded polytetrafluoroethylene grafts were used effectively. Limb salvage and wound healing were achieved in 100% of the patients without untoward sequelae. It is concluded that unrecognized PVD in patients undergoing coronary artery bypass grafting can lead to significant morbidity. Patients at risk may be identified with a combination of history, physical examination and non-invasive testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Intraoperative iliac artery stents: combination with infra-inguinal revascularization procedures.

Iliac artery percutaneous transluminal angioplasty (PTA) can effectively provide in-flow for subsequent distal vascular reconstruction. Iliac artery stents may improve the initial hemodynamics and long term patency of PTA, and thus may be well-suited for combined proximal PTA with distal bypass procedures. This report reviews our preliminary experience with iliac artery stenting in combination with infra-inguinal vascular reconstruction. Thirteen iliac artery stent procedures combined with simultaneous distal revascularization were performed in 11 patients. Ten procedures were performed for limb salvage, two for disabling claudication, and one before planned orthopedic surgery. Distal revascularization procedures included seven femoropopliteal, four femorotibial bypasses, one common femoral endarterectomy, and one thrombectomy of a femoropopliteal bypass. Stent placement was technically successful in all patients. Mean pre-operative ankle-brachial index (ABI) was 0.41 (+/- 0.28), which improved to 0.91 (+/- 0.18) post-operatively (P < 0.0001). Mean systolic iliac artery gradients across the lesions improved from 27.1 (+/- 9.8) mm Hg to 2.7 (+/- 3.4) mm Hg after stent placement (P < 0.0001). Mean follow-up is 5.8 months (range 1-12 months). Two femoropopliteal bypass grafts occluded in the follow-up period. One occlusion was caused by a mid-vein graft stenosis that was repaired with subsequent graft patency. The other graft occlusion occurred in a patient with rest pain who did not require a second bypass procedure, as the ABI increased from 0.3 to 0.7 following stent placement with resolution of symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Coexistent abdominal aortic aneurysm and renal carcinoma: management options.

Renal carcinoma (RCA) presenting in association with abdominal aortic aneurysm (AAA) is extremely rare, with only sporadic case reports previously described. The management of six cases of AAA and concomitant RCA presenting to a single institution from March, 1991 through December, 1993 was reviewed and management options considered. AAAs ranged in size from 4.5-7.0 cm (mean, 5.6 cm). Three left renal carcinomas were resected via a retroperitoneal approach simultaneous to repair of the AAA. One right renal carcinoma was resected in combination with repair of an AAA through a transperitoneal approach. The fifth case was managed by left nephrectomy, followed by interval aneurysmectomy, and the sixth case was managed by nonsurgical methods because of the presence of widely metastatic disease. Renal malignancies included five renal cell carcinomas and one transitional cell carcinoma. Three patients remain free of disease 8-11 months postoperatively, and one patient had metastatic disease detected 19 months postoperatively. Two deaths have occurred; one due to a massive CVA 1 month following a combined aneurysmectomy and left nephrectomy, and a second due to unknown etiology in the patient managed non-surgically. No peripheral vascular or aortic graft related complications have occurred. The treatment of AAA and RCA should be governed by the size of the AAA, the location of the cancer, and the extent of malignant disease. Simultaneous resection is safe and effective in patients with coexistent AAA and renal cancer. Left sided tumors should be resected via a retroperitoneal approach that also provides excellent exposure for simultaneous AAA resection.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Duplex scanning for the intraoperative assessment of infrainguinal arterial reconstruction: a useful tool?

Duplex scan, arteriography, and graft flow rates were used intraoperatively to assess 56 infrainguinal arterial reconstructions for technical error. Intraoperative duplex scan identified a technical defect or low graft flow velocity in 22 of 56 (39%) grafts. Eleven of the defects were judged to be clinically significant and were corrected. Four of these defects were missed by the completion arteriogram. One technical defect identified by completion arteriography was missed by duplex scan. Fifty percent (5/10) of grafts with an abnormal intraoperative duplex scan which were not corrected occluded within 30 days. Graft flow rates measured by the electromagnetic flowmeter were neither predictive of technical defect nor early graft outcome. Although the sensitivity of arteriography and duplex scan (88% sensitivity for both) were both high for predicting early graft occlusion, the combination of duplex scan and completion arteriography was significantly more accurate (p less than .0001) in predicting early graft outcome than either study alone. Duplex scan identified significant graft defects which were not detected by completion arteriography or graft flow rate measurement. The duplex scan also provided hemodynamic information which was predictive of early graft outcome. The duplex scan can be an important adjunct to completion arteriography for the intraoperative assessment of infrainguinal arterial reconstruction.

Adult↗
PubMed1992

The ischemic window: a method for the objective quantitation of the training effect in exercise therapy for intermittent claudication.

Twenty-two patients with intermittent claudication were prospectively enrolled in a 12-week program of supervised, graded treadmill exercise therapy. Severity and distribution of arterial occlusive disease were ascertained by noninvasive determination of segmental lower extremity blood pressures and waveforms. No attempt was made to modify risk factors for atherosclerotic occlusive disease. The exercise-induced reduction of the ankle pressure and its recovery were recorded over time, and the area under this curve, the "ischemic window," represents the severity of the ischemic deficit. Absolute systolic ankle pressure, ankle-brachial index, maximum walking time, claudication pain time, and the ischemic window were measured before and after exercise training in all subjects. Maximum walking time and claudication pain time increased 659% and 846%, respectively, among the 19 patients completing the 12-week program (p = 0.001; p = 0.0002). These patients underwent a mean reduction of 58.7% in the ischemic window after a standardized workload (p less than 0.05), and this correlated with the degree of symptomatic improvement. Absolute ankle pressure and ankle-brachial index were unchanged after exercise training. This study confirms the utility of supervised exercise therapy in the treatment of intermittent claudication. The ischemic window is a useful method for quantifying the ischemic deficit produced by exercise and provides a reproducible means of documenting functional improvement in patients undergoing exercise training.

Aged↗
PubMed1991

Thoracic aortic ectasia in a patient with Takayasu's disease.

Arterial aneurysm formation occurs in 15 to 20% of patients with Takayasu's disease. The timing of surgical intervention of these aneurysms is controversial. A case of ectasia of the descending thoracic aorta in a patient with Takayasu's disease is presented. The diagnosis and timing of surgical intervention of aneurysms associated with Takayasu's disease are discussed.

Adult↗
PubMed1991

Spontaneous carotid dissection: duplex scanning in diagnosis and management.

The clinical, duplex, and angiographic findings in six patients with seven spontaneous extracranial carotid artery dissections are reported. Four dissections resulted in internal carotid artery occlusion. These patients complained of ipsilateral headache followed by contralateral hemiplegia. The other three dissections involved the common carotid artery and resulted in dual (one true and one false) lumens. Two of these dissections were asymptomatic. All dissections were treated nonoperatively with anticoagulant therapy. Neurologic deficits improved or disappeared in all symptomatic patients. On follow-up studies, one of the four internal carotid occlusions completely resolved with normalization of the duplex examination. All three dual lumen dissections remained patent on serial studies. Diagnostic duplex characteristics, both conclusive and supportive, of carotid dissections are described. Duplex scanning is shown to be accurate in diagnosing and ideally suited for serially following spontaneous carotid dissections.

Adult↗
PubMed1991

Experience with laser-assisted balloon angioplasty and a rotary angioplasty instrument: lessons learned.

Favorable early results with mechanical angioplasty devices and laser-assisted balloon angioplasty have resulted in aggressive marketing and a rapid increase in the use of these devices for the treatment of femoropopliteal occlusive disease. Recent reports, however, have questioned the durability of these less invasive procedures. Since 1986 we have been involved in the clinical investigation of the Kensey dynamic angioplasty instrument and laser-assisted balloon angioplasty. One hundred two balloon angioplasty procedures assisted by the Nd:YAG laser (n = 56) and the Kensey dynamic angioplasty instrument (n = 46) were performed for the treatment of femoropopliteal occlusive lesions. Both Kensey dynamic angioplasty instrument and laser-assisted balloon angioplasty groups were similar with regard to age, operative indication, preoperative ankle-brachial index, lesion length, and distal runoff. Mean follow-up was 19 months in the Kensey dynamic angioplasty instrument group and 15 months in the laser-assisted balloon angioplasty group. Technically successful recanalization was achieved in 67% of Kensey dynamic angioplasty instrument-assisted balloon angioplasty procedures and 82% of laser-assisted balloon angioplasty procedures. Early hemodynamic and clinical improvement was obtained in 59% of Kensey dynamic angioplasty instrument-assisted balloon angioplasty procedures and 57% of laser-assisted balloon angioplasty procedures. Two-year clinical success by life-table analysis was 37% in the Kensey dynamic angioplasty instrument group and 19% in the laser-assisted balloon angioplasty group. The level of subsequent surgical revascularization was not altered in any patient by Kensey dynamic angioplasty instrument-assisted balloon angioplasty or laser-assisted balloon angioplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Initial results and subsequent outcome of laser thermal-assisted balloon angioplasty of 56 consecutive femoropopliteal lesions.

Laser thermal-assisted balloon angioplasty (LABA) was prospectively applied in the treatment of 56 atherosclerotic femoropopliteal occlusive lesions in 51 consecutive patients. All procedures were performed in the operating room using a neodynium:yttrium-aluminum-garnet (Nd:YAG) laser source, and patients were evaluated for immediate and long-term hemodynamic and clinical improvement. Technically successful recanalization was achieved in 82% of cases, with 57% of all patients (32 of 56) obtaining early hemodynamic and clinical improvement. Long-term clinical success (by life-table analysis) was obtained by only 22.5% at 6 months, and only 13.5% at 12 months. Patients presenting with intermittent claudication did significantly better than those presenting for limb salvage (p = 0.01), and trends toward improved outcome were noted for short versus long lesions as well as for patients with "good" versus "poor" distal runoff (NS). Procedure-related morbidity occurred in 14%, and there was one peri-procedural mortality (1.8%). We conclude that the use of LABA is associated with long-term clinical success in only a small proportion of patients, and that widespread clinical application of this technique is not indicated at the present time.

Adult↗
PubMed1990

Increased infection rate in double-lumen versus single-lumen Hickman catheters in cancer patients.

Over the 48-month period from January 1983 through December 1986, 51 single-lumen (SL) and 94 double-lumen (DL) indwelling central venous (Hickman) catheters were placed in 118 patients with malignant disease. We reviewed these cases retrospectively to determine the types and frequency of complications requiring catheter removal. The catheters were in place a total of 18,397 days. Overall, 14% (7/51) of SL and 21% (20/94) of DL catheters were removed due to infection. Of those catheters becoming infected, DL catheters were infected earlier. SL catheters that became infected averaged 213 days of use before removal, whereas DL catheters becoming infected averaged only 78 days before removal (P less than or equal to .02). The infection rate was significantly less in SL (one infection per 1,210 days) than in DL catheters (one infection per 496 days) (P less than or equal to .02). Thus because of its significantly reduced risk of infection, the single-lumen Hickman may be the preferred catheter for long-term venous access in many patients.

Adult↗
PubMed1990

The use of composite grafts in femorocrural bypasses performed for limb salvage: a review of 108 consecutive cases and comparison with 57 in situ saphenous vein bypasses.

We retrospectively reviewed the results of 108 consecutive femorocrural bypasses performed with prosthetic/autogenous composite graft material and compared these with the results of 57 crural bypasses using greater saphenous vein by the in situ technique. Indication for operation in all cases was the salvage of an otherwise imminently threatened limb. Polytetrafluoroethylene-composite grafts (n = 87) and human umbilical vein-composite grafts (n = 21) were placed only in patients lacking suitable autogenous material for in-line reconstruction. Patient groups were similar with respect to mean age, prevalence of arterial disease risk factors, quality of the distal runoff, and location of the distal anastomosis. Cumulative patency rates at 1 year by life-table analysis were 81.9%, 34.6%, and 12.1% for the in situ, polytetrafluoroethylene-composite and human umbilical vein-composite groups, respectively. At 2 years these were 63.9%, 29.9%, and 6.0%, respectively (p less than 0.025). Cumulative limb salvage at 1 year was 70.6%, 62.3%, and 32.7%, respectively. Wound-related complications occurred in 52.4% of human umbilical vein-composite, 38.6% of in situ, and 18.3% of polytetrafluoroethylene-composite bypasses (p less than 0.05). On the basis of these results, we conclude that femorocrural bypass with polytetrafluoroethylene-composite graft is an acceptable form of distal reconstruction for limb salvage in patients lacking sufficient lengths of autogenous vein. We no longer use human umbilical vein for composite construction.

Aged↗
PubMed1988

The Kensey catheter: preliminary results with a transluminal atherectomy tool.

The Kensey dynamic angioplasty instrument is an atherectomy device approved by the Food and Drug Administration that uses a rotating cam tip housed within a flexible polyurethane catheter to recanalize obstructed and stenotic arteries. Twenty patients with significant femoral arteriosclerotic occlusive disease underwent attempted transluminal endarterectomy of 23 extremities with the Kensey catheter. Significant improvements of superficial femoral artery luminal diameter was achieved in 10 of 13 patients with stenosis and passage of the spinning catheter tip at 60,000 to 90,000 rpm through areas of complete occlusion was successful in 4 of 10 cases. Balloon dilatation was used as an adjunct to increase the diameter of the superficial femoral artery lumen in 11 of 14 successful cases. This preliminary report provides technical data and short-term follow-up of this new innovative vascular tool.

Angioplasty, Balloon↗
PubMed1987

Arterialization of reversed autogenous vein grafts: quantitative light and electron microscopy of canine jugular vein grafts harvested and implanted by standard or improved techniques.

To provide sequential, quantitative analysis of the cellular events occurring in reversed autogenous vein grafts after implantation and potential modifications of these events, two groups of veins were evaluated. Veins prepared by standard techniques of unmonitored pressure distension with cold heparinized saline solution, tributary ligation adjacent to the wall, and storage at 4 degrees C were morphometrically compared with veins harvested by means of a modified protocol of papaverine irrigation, tributary ligation away from the graft wall, pressure distension to 100 mm Hg with heparinized blood containing papaverine at body temperature, storage in identical solution at 4 degrees C, and implantation while distended. Unilateral jugular veins harvested from dogs with the modified technique (IRJV,N = 9) or standard technique (SRJV,N = 9) were implanted into carotid arteries, retrieved at 30 minutes, 2 days, and 10 days postoperatively along with the contralateral control vein after perfusion fixation in situ, and examined microscopically to quantitate intimal-medial thickness and endothelial damage (denudation and ultrastructural alterations). All IRJVs remained endothelialized, whereas SRJVs had 19% and 40% endothelial denudation at 30 minutes and 2 days, respectively, as well as massive neutrophil, platelet, and monocyte involvement. In contrast, IRJVs had only a modest infiltration of monocytes beginning early after implantation and culminating in their localization beneath endothelial cells; these endothelial cells increased in number during the 10-day period. Although SRJVs exhibited nearly complete reendothelialization over the luminal surface of macrophages by 10 days, endothelial damage was consistently higher than that of IRJVs at all periods and intimal-medial thickness was significantly greater at 10 days (65 +/- 0 vs. 57 +/- 0 micron, respectively; p less than 0.001). These findings suggest that endothelial preservation with improved harvesting techniques inhibits thrombosis and limits wall thickening and also that macrophages may play a protective role by promoting endothelial proliferation.

Animals↗
PubMed1987

Freshly harvested cadaveric venous homografts as arterial conduits in infected fields.

Six patients with patent multilevel prosthetic grafts (three axillofemoral-femoral grafts, an aortobifemoral graft, an axillofemoral and femoral-anterior tibial graft, and an axillofemoral and femoral-popliteal graft) that demonstrated overt infection involving both the proximal inflow (one infrarenal aorta, five axillary arteries) and groin anastomoses required complete graft excision. Cadaveric inferior vena cava, common and external iliac, common and superficial femoral, and greater saphenous veins were harvested in conjunction with multiple organ donor procedures. Identical anatomic reconstruction within the infected fields was accomplished, with patency and distal perfusion maintained for intervals sufficient to achieve complete resolution of infection in all cases. This interval of revascularization with a venous homograft has served as a temporizing maneuver, which permitted eradication of infection and allowed subsequent reimplantation of prosthetic graft material without associated reinfection in the two instances in which it was required. Use of freshly harvested large-caliber caval, iliac, and femoral homograft veins as arterial substitutes in infected fields has not been previously reported. Case histories and a review of the venous homografting literature are included.

Aged↗
PubMed1985

The mangled extremity syndrome (M.E.S.): a severity grading system for multisystem injury of the extremity.

The severely mangled extremity presents a challenge in appropriate surgical management. Very few objective data were found about this problem. To clarify the situation, criteria for a "mangled extremity' were defined, a multidisciplined approach employed, and a retrospective graduated grading system developed. Sixty consecutive trauma patients with severely injured extremities during the past 3 years were reviewed. Seventeen patients fit the category of Mangled Extremity Syndrome (M.E.S.). Injuries were retrospectively classified using a graduated grading system directed at four major tissue systems of the extremity involved (integument, nerve, artery, and bone). Additional scoring items were included to define the significance of trauma sustained outside the extremities. Patients who ultimately came to amputation could have been identified preoperatively at initial emergency evaluation utilizing this graduated grading system. Retrospective data suggest that a Mangled Extremity Syndrome Index (M.E.S.I.) of 20 is the dividing line below which functional limb salvage can be expected and above which limb salvage is improbable. Prospective application of this system, as well as an organized multidisciplined approach, could be useful in the identification of functionally retrievable versus probably irretrievable extremities, thus identifying and helping define the indications for amputation. The grading system criteria and results in these 17 patients form the basis of this report.

Adult↗
PubMed1984

Optimal techniques for harvesting and preparation of reversed autogenous vein grafts for use as arterial substitutes: a review.

Since the first successful use of an autogenous vein graft for arterial reconstruction by Gluck in 1898 and the establishment of the scientific basis for the use of veins as arterial substitutes by Carrell and Guthrie in the early 1900s, reversed autogenous veins have been used extensively in arterial reconstructive operations. Despite being the preferred material for reconstruction, reversed autogenous vein is not an ideal graft material. The primary problem is structural alterations in the implanted vein predisposing to graft failure. Most of these failures occur within the first few months after graft implantation and are though to be due, in part, to endothelial damage incurred during harvesting and preparation of the vein. This review focuses on technical aspects of vein graft harvesting associated with alterations in endothelial morphology including dissection technique, types of irrigation and storage solutions used, temperature of these solutions, distension pressures, and pharmacologic agents. An optimal technique incorporating subcutaneous and perivenous infiltration with papaverine, atraumatic dissection, controlled gradual distension, and storage of the distended vein in cold heparinized blood containing papaverine should produce grafts with improved endothelial preservation and patency rates compared with grafts harvested by techniques in widespread use at present. The importance of morphologically and functionally intact endothelium in reversed vein grafts, a comparison to that produced by in situ vein grafting, and its possible clinical implications are discussed.

Arterial Occlusive Diseases↗