PubMed Health⌕ Search

Biomedical subjects

D F Bandyk

Publications and source records attributed to D F Bandyk.

At least 19 recordsLinked to original sources
PubMed1992

Use of stress thallium imaging to stratify cardiac risk in patients undergoing vascular surgery.

Reduction of the cardiac morbidity associated with major vascular procedures requires identification of high risk patients prior to operation. This retrospective study reviews the records of 126 consecutive patients who underwent 141 major vascular procedures to determine the accuracy of preoperative clinical, laboratory (ECG), and cardiac function testing (stress thallium-201 scintigraphy, left ventricular ejection fraction scan) in predicting perioperative cardiac complications. An abnormality on oral dipyridamole or treadmill thallium imaging was demonstrated prior to 71 (61%) of 116 procedures and included 20 fixed and 51 reperfusion (reversible) defects. No patient died within 30 days of operation, but 11 minor (ventricular arrhythmia) and 15 major (myocardial infarction, ischemic congestive heart failure) cardiac complications occurred. A reperfusion defect on stress thallium imaging accurately (94% sensitivity, 56% specificity, 98% negative predictive value) identified high-risk patients while accepted clinical rating systems (Goldman, Cooperman, Eagle) and preoperative level of left ventricular ejection fraction were less predictive of adverse cardiac events. Patients without myocardium at risk by coronary angiography, but a reperfusion defect on stress thallium imaging were found to be at high risk for a cardiac complication. The study data support the use of stress thallium imaging to stratify cardiac risk prior to major arterial surgery.

Adult↗
PubMed1992

Diagnosis and treatment of biomaterial-associated vascular infections.

Management of biomaterial-associated vascular infections requires an understanding of pathogenetic mechanisms, risk factors, and microbiologic characteristics. Staphylococci sp., especially slime-producing strains of S. epidermidis are the prevalent pathogens. Experimental and clinical studies have indicated in situ replacement, particularly with an antibiotic-bonded prosthesis, as effective treatment for infections caused by coagulase-negative staphylococci. When sepsis is a presenting sign, prompt intervention, total excision of the prosthesis, and antibiotic administration are required.

Animals↗
PubMed1992

The role of duplex scanning versus angiography in predicting outcome after balloon angioplasty in the femoropopliteal artery.

Duplex-derived velocity measurements were used to assess the hemodynamics of 64 femoropopliteal arterial sites in 59 patients after angiographically successful percutaneous transluminal balloon angioplasty. With use of angiography as the gold standard, percutaneous transluminal balloon angioplasty was judged to be successful if (1) evidence existed of a "split" caused by intimal dissection and splitting of atherosclerotic plaque; and (2) no significant diameter-reducing residual stenosis was observed at the percutaneous transluminal balloon angioplasty site. At 1 month, 55 limbs (86%) were hemodynamically and clinically improved by SVS/ISCVS clinical criteria for chronic limb ischemia. Of the 55 percutaneous transluminal balloon angioplasty sites, duplex scanning had identified 40 (63%) sites with a less than 50% diameter-reducing stenosis and 15 (27%) sites with a greater than 50% diameter-reducing stenosis within a week after percutaneous transluminal balloon angioplasty. Independent review of the 55 angiograms taken after percutaneous transluminal balloon angioplasty identified 39 sites (71%) with a split and 16 sites (29%) without. By life-table analysis, a greater than 50% diameter-reducing stenosis predicted a worse clinical outcome (15% at 1 year) compared with the presence of a less than 50% diameter-reducing stenosis (84% at 1 year) (p less than 0.001; log rank test). The presence or absence of an angiographic split was not a predictive factor of percutaneous transluminal balloon angioplasty outcome (split, 61% at 1 year; no split, 62% at 1 year) (p = 0.832; log rank test). The detection of a functional residual stenosis by duplex scanning did not correlate with angiographic appearance, but was predictive of clinical failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Monitoring functional patency of percutaneous transluminal angioplasty.

Duplex scanning and Doppler-derived blood pressure measurements were used to serially monitor lower limb hemodynamics in 73 patients who underwent percutaneous transluminal angioplasty. Ninety percutaneous transluminal angioplasty sites judged technically satisfactory by arteriography were evaluated. Significant hemodynamic improvement was seen in 81 (90%) of the 90 limbs, although both hemodynamic and clinical improvement were achieved in only 77 (86%) limbs. Duplex scanning within 1 week of successful angioplasty identified moderate (20% to 49% diameter reduction) or severe (greater than 50% diameter reduction) residual stenosis in 49 (63%) of 77 balloon-dilated arterial segments. The presence of a greater than 50% diameter reduction residual stenosis predicted further restenosis and late clinical failure (11% success rate at 1 year). When the degree of residual stenosis at the percutaneous transluminal angioplasty site was less than 50% diameter reduction by duplex scanning, the procedure was durable (80% success rate at 2 years), even in patients with critical ischemia, poor runoff, or diabetes mellitus.

Angioplasty, Balloon↗
PubMed1991

Antibiotic-bonded PTFE vascular grafts: the effect of silver antibiotic on bioactivity following implantation.

Use of an infection-resistant vascular prosthesis has appeal for grafting in sites of potential contamination or to replace graft segments involved in low-grade infections caused by coagulase-negative staphylococci (CNS). In this study, antibiotic retention on polytetrafluoroethylene (PTFE) grafts prepared using three antibiotic-bonding methods was compared following implantation into the arterial circulation. Ciprofloxacin or silver-ciprofloxacin was bonded to PTFE surfaces by surfactant-mediated or direct bonding methods. Antibiotic-bonded grafts of each type (n = 8) or control grafts (n = 2) were used to replace the carotid or femoral arteries of 10 dogs. Duplicate grafts segments (0.5 x 0.5 cm) were explanted at various time intervals ranging from 1 hr to 14 days later and imprinted onto culture plates of Klebsiella pneumonia. Antibiotic retention (micrograms/ml) was determined by measuring zones of inhibition and correlated with known disc concentrations of ciprofloxacin. Antibacterial bioactivity of grafts bonded with silver-antibiotic complexes was superior (P less than 0.02) to bonding of antibiotic alone at 3 and 24 hr following implantation. Ciprofloxacin retention in excess of the minimum bactericidal concentration (0.5 microgram/ml) of Staphylococcus epidermidis was demonstrated on all silver-antibiotic-bonded grafts after 14 days of implantation. At 7 and 14 days following implantation, the bioactivity of all antibiotic-bonded grafts exceeded 0.125 micrograms/ml of ciprofloxacin, the minimum inhibitory concentration of S. epidermidis. Bonding of silver-ciprofloxacin on PTFE grafts provided an effective source of local antibiotic release at levels which may be useful for bypass grafting in contaminated wounds or for in situ replacement of grafts infected by CNS.

Animals↗
PubMed1991

Experience with in situ saphenous vein bypasses during 1981 to 1989: determinant factors of long-term patency.

From 1981 to 1989, 361 consecutive in situ saphenous vein bypasses were performed. Indications for revascularization were critical limb ischemia (n = 335, 93%), popliteal aneurysm (n = 15, 4%), and claudication (n = 11, 3%). Outflow tract was the popliteal artery in 116 (32%) and tibial artery in 245 (68%) of bypasses. At 6 years primary patency was 63% and secondary patency was 81%. During the performance of the in situ bypass procedure, 86 (24%) venous conduits were modified because of a technical failure (n = 49, 13%) or an inadequate vein segment (n = 37, 10%). Secondary patency at 4 years for bypasses requiring modification was 72% compared to 84% for bypasses not modified (p less than 0.05). Atherosclerotic disease of the inflow artery necessitating endarterectomy, patch angioplasty, or replacement lowered primary patency at 3 years (69%) compared to the inflow artery not requiring reconstruction (46%, p less than 0.02). In the follow-up period, 95 (26%) bypasses were revised because of thrombosis or hemodynamic failure. Bypasses requiring revision had a 4-year secondary patency of 68% compared to 88% for bypasses not revised (p less than 0.02). The first 179 cases (1981 to 1985) were compared to the subsequent 182 cases (1986 to 1989). The secondary patency at 3 years for the latter half (92%) compared to the first half (80%) of the experience was significantly improved (p less than 0.02). The secondary patency for bypasses not requiring revision was significantly improved (p less than 0.02) for the latter half (n = 142, 97%) compared to the first half (n = 124, 83%) of the series. Long-term patency with the in situ saphenous vein bypass is dependent on surgical experience, quality of the venous conduit, and atherosclerotic disease of the inflow artery that necessitates reconstruction. Meticulous surgical technique and compulsive bypass surveillance results in superior long-term patency.

Anastomosis, Surgical↗
PubMed1991

Durability of vein graft revision: the outcome of secondary procedures.

Occlusive lesions that reduced graft blood flow and ankle systolic pressure were identified in 83 femorodistal saphenous vein bypasses by use of duplex scanning or arteriography. Sites of stenosis included vein conduit (n = 41), anastomoses (n = 20), outflow arteries (n = 15), or inflow (n = 9) arteries. One hundred three secondary procedures consisting of vein-patch angioplasty (n = 31), sequential (n = 21) or interposition (n = 17) graft placement, percutaneous transluminal balloon angioplasty (n = 17), or excision of the lesion and primary anastomosis (n = 16) were performed to correct primary (n = 85) or recurrent (n = 18) graft stenoses. Cumulative graft patency after reintervention was 96% at 1 year, and 85% at 5 years. Stenosis or occlusion of revision sites was less after excision (0 of 16) or replacement (1 of 17) of abnormal segments compared to vein-patch angioplasty (8 of 31) or balloon angioplasty (9 of 18). Sequential or jump grafts constructed to improve graft outflow impaired by either myointimal or atherosclerotic occlusive lesions were the least durable secondary procedures. Five of eight graft failures in this series resulted from sequential/jump graft occlusion. All categories of secondary procedures normalized graft and limb hemodynamics, although only one third of patients reported symptoms of limb ischemia before revision. Surveillance of infrainguinal vein bypasses for occlusive lesions is a valid concept to salvage patent but hemodynamically-failing grafts. Secondary procedures that excised the lesion, used autologous tissue reconstruction, and normalized hemodynamics at the revision site and in the vein bypass were associated with a low incidence of restenosis and prolonged graft patency.

Aged↗
PubMed1991

Percutaneous intraarterial thrombolysis in the treatment of thrombosis of lower extremity arterial reconstructions.

Vascular grafts may be salvaged with thrombolytic therapy after acute occlusion as an alternative to balloon catheter thrombectomy. From October 1987 to May 1990, 15 arterial bypasses to the lower extremity (infrainguinal saphenous vein [n = 7] or expanded polytetrafluoroethylene [n = 6], and Dacron aortofemoral bifurcation graft limbs [n = 2]) were treated for 30 occulsions with intraarterial urokinase (390,000 IU to 5,808,000 IU) infused from 3 to 40 hours. The origins of 15 graft occlusions were morphologic defects (intimal hyperplasia with anastomotic or conduit stricture), pseudoaneurysm, or progression of disease distal to the graft. Two occlusions were attributed to coagulation disorders. A cause could not be identified for 13 occlusions. Patency was initially restored to all grafts with use of thrombolytic therapy, however, adjunctive surgical thrombectomy to remove persistent thrombus from the graft or outflow vessels was required after six thrombolytic infusions. One graft in the series could not be salvaged leading to below-knee amputation. Graft defects were corrected by balloon angioplasty (n = 7) or surgical revision of the conduit (n = 8). Five significant hemorrhagic complications occurred from the catheter insertion site requiring four emergent surgical procedures and resulting in the death of a fifth patient from a myocardial infarction. This technique allows chemical thrombectomy of branch arteries distal to the graft and inaccessible to a balloon embolectomy catheter, and permits diagnosis of abnormal graft morphology that may be the cause of the graft occlusion. Graft reocclusion can be expected if technical defects in the arterial reconstruction are not revised or hypercoagulable states are not treated.

Angioplasty, Balloon↗
PubMed1991

Comparison of serum and tissue antibiotic levels in diabetes-related foot infections.

Parenteral antibiotics are used as an adjunct to amputation or operative debridement for patients with diabetes who require emergency surgery for a septic foot. In 26 patients with a diabetes-related foot infection, one dose of various intravenous antibiotic regimens (gentamicin and clindamycin, ticarcillin/clavulanate, ampicillin/sulbactam) was administered during the hour before the procedure, and assays were performed to measure the antibiotic serum and tissue levels at the time of surgical debridement. Aerobic and anaerobic cultures were performed on infected tissue. The 172 bacterial isolates, including 95 aerobes and 77 anaerobes, (6.6 isolates per patient) underwent antibiotic susceptibility testing. Antibiotic levels were calculated by biologic assay from serum and tissue biopsies from the viable margins of the surgical site, which subsequently healed primarily or supported a split-thickness skin graft. Sixteen of the patients achieved therapeutic serum levels, and therapeutic tissue levels were reached in six patients at the time of surgery. A significantly lower number of patients had therapeutic tissue levels compared to serum levels (p less than 0.01, chi square). Initial intravenous antibiotic administration provides inadequate tissue concentrations for treating foot infections in patients with diabetes. Adequate serum antibiotic levels do not reflect therapeutic tissue antibiotic levels at the surgical margins in this group of patients.

Anti-Bacterial Agents↗
PubMed1991

In situ replacement of vascular prostheses infected by bacterial biofilms.

Late prosthetic graft infections are commonly the result of coagulase-negative staphylococci that survive within a biofilm on prosthetic surfaces and provoke perigraft inflammation. The indolent nature and microbiologic characteristics of bacterial biofilm infections coupled with the morbidity of graft excision and extraanatomic bypass grafting prompted us to use in situ graft replacement in 15 patients admitted to the hospital with 17 infected graft segments at a mean (+/- SEM) time interval of 70 +/- 16 months after graft implantation (n = 6) or revision (n = 9). Since 1986, 17 grafts (14 aortofemoral, 2 axillofemoral, and 1 femoropopliteal) infected by bacterial biofilms have been treated. Signs on admission included femoral pseudoaneurysm (n = 7), perigraft abscess (n = 6), or graft-cutaneous sinus tract (n = 4). No patient exhibited septicemia. At operation graft incorporation was absent and Gram's stain of perigraft exudate showed polymorphonuclear leukocytes but no bacteria. Culture of explanted graft material isolated coagulase-negative staphylococci (n = 12), Staphylococcus aureus (n = 1), and no growth (n = 2). All patients were successfully treated by a regimen that included parenteral antibiotics, removal of involved graft material, excision of inflamed perigraft tissue, and in situ replacement with an expanded polytetrafluoroethylene prosthesis. No deaths, graft thromboses, or deep wound infections occurred after operation. Recurrent graft infection did not develop during a follow-up interval that ranged from 5 to 50 months (mean, 21 months). Diagnosis of vascular prosthesis infection caused by bacterial biofilms can be based on signs at admission and operative findings. Complications of this perigraft infection can be eradicated by antibiotic administration, local debridement, and in situ graft replacement.

Aged↗
PubMed1990

Early patency of in situ saphenous vein bypasses as determined by intraoperative velocity waveform analysis.

Intraoperative velocity waveform analysis following in situ saphenous vein bypass grafting can identify abnormal hemodynamic conditions that correlate with the presence of a technical error or likelihood of perioperative thrombosis. Pulsed Doppler spectral analysis was used at operation to measure peak systolic blood flow velocity in the distal graft segment of 83 in situ saphenous vein bypasses to the popliteal (n = 35) or tibial (n = 48) arteries. Blood flow velocities were measured in the smallest diameter graft segment below the knee. Peak systolic blood flow velocity was greater than 40 cm/sec in 77 (93%) of grafts, and no early graft failures occurred. Low blood flow velocity (peak systolic blood flow velocity less than 40 cm/sec) was measured in six bypasses (7%) and was attributed to large (greater than 5 mm) vein diameter, residual hemodynamically significant lesions (intact valve leaflet, proximal arteriovenous fistula), or sclerosed vein segments. With the correction of these abnormalities, the 30 day patency for the entire series was 100%. The measurement of low blood flow velocity in the distal segment of an in situ saphenous vein bypass is an uncommon occurrence and mandates a thorough evaluation of the arterial reconstruction for correctable lesions.

Adult↗
PubMed1990

Impact of postantibiotic effect on bacterial adherence to vascular prostheses.

The brief exposure of bacteria to high antibiotic concentrations can result in prolonged suppression of bacterial growth termed postantibiotic effect (PAE). A pathogenic Staphylococcus epidermidis strain (RP-62) was exposed to 2X and 6X minimum inhibitory concentrations (MIC) of cefazolin, vancomycin, or rifampin for 1 hr and incubated for 2 to 24 hr in inhibitory-free broth. PAE was defined as the difference in time required for a 1.0 log increase in test (T) vs control (C) cultures (PAE = T-C). PAE was observed only for rifampin: 6 hr at 2X MIC and 8 hr at 6X MIC. Bacterial adherence to Dacron grafts was calculated in PAE vs control cultures by a quantitative culture technique for graft specimens incubated 2 to 24 hr. A demonstrable PAE and its impact on adherence were found to be both antimicrobial and concentration dependent. A significant decrease in staphylococcal adherence to velour-knitted Dacron was demonstrated by rifampin at 2X MIC (P less than 0.05) and 6X MIC (P less than 0.01). This phenomena may be useful in reducing bacterial adherence and colonization of bioprosthetics in the perioperative period. Preoperative suppression of staphylococcal skin flora by high dose antimicrobials can alter the capacity of these organisms to adhere to vascular prosthetic grafts and, if incorporated into antibiotic prophylaxis regimens, may reduce graft colonization.

Anti-Bacterial Agents↗
PubMed1990

An outpatient anticoagulation protocol managed by a vascular nurse-clinician.

Lifetime anticoagulation has become a therapeutic option for surgical patients with hypercoagulable states or prosthetic arterial bypass grafts. However, physicians may not achieve optimal anticoagulation or may attempt to limit the length of the therapy period because of the perceived morbidity from hemorrhagic complications of Coumadin therapy. A protocol for anticoagulant therapy monitored and regulated by a vascular nurse-clinician was reviewed. Coumadin was prescribed for 1,891 patient-months to 93 patients to maintain their prothrombin time 1.5 to 2 times control (range: 18 to 24 seconds). The mean (+/- SD) prothrombin time for the study population was 19.8 +/- 1.8 seconds. During follow-up, 472 (14%) of 3,479 prothrombin times measured were below the therapeutic range (n = 232) or prolonged (n = 240), prompting an adjustment in the Coumadin dose in 82 (88%) patients. Four patients developed recurrent vascular graft thrombosis while receiving anticoagulation. There were 6 major and 11 minor hemorrhagic complications. Patients with a chronic risk for arterial or venous thrombosis can have out-patient anticoagulant therapy administered at optimal intensity and regulated safely with a low incidence of hemorrhagic and thrombotic events.

Adolescent↗
PubMed1990

Postoperative surveillance of infrainguinal bypass.

An effective graft-surveillance protocol needs to be applicable to all patients; practical in terms of time, effort, and cost; reliable; and able to detect, grade, and assess progression of lesions. The combination of pressure measurements and duplex color-flow imaging is the most effective technique for infrainguinal bypass surveillance. The accuracy of this protocol for the detection of graft stenosis is comparable to arteriography, and graft revision can be recommended and implemented based on noninvasive testing alone. Although similar anatomic and blood-flow data can be obtained by conventional duplex scanning, graft surveillance using color-flow imaging is preferred because both vascular anatomy and hemodynamics are evaluated simultaneously, a feature that improves diagnostic accuracy and reduces examination time. By contrast, resting ABI measurements alone are unable to identify reliably a failing graft; they are useful primarily for confirming technical adequacy and relief of ischemia. Data exist that confirm that long-term patency of infrainguinal bypasses is improved if hemodynamically significant stenoses are revised prior to graft thrombosis rather than revised or replaced after thrombosis. Both symptomatic and asymptomatic patients should undergo graft revision when noninvasive testing has confirmed the presence of a correctable lesion that reduces both limb pressure (change in ABI greater than 0.15) and graft blood-flow velocity (Vp less than 45 cm per second). Drops in pressure can occur in the absence of abnormalities in graft blood flow, but this condition does not indicate impending graft thrombosis. The identification of high-grade (greater than 75 per cent) stenosis by duplex scanning or color-flow imaging has been uniformly associated with a reduced ABI and increased risk of graft thrombosis. Less-severe lesions can be followed for disease progression as long as graft blood flow is adequate to sustain patency. In bypasses with low flow but no correctable abnormality, oral anticoagulation with warfarin sodium may decrease the incidence of graft thrombosis.

Arterial Occlusive Diseases↗
PubMed1990

Anastomotic femoral pseudoaneurysm: an investigation of occult infection as an etiologic factor.

Occult infection was investigated as an etiologic factor in the formation of femoral anastomotic pseudoaneurysms associated with prosthetic vascular grafts. Forty-five femoral pseudoaneurysms with no clinical evidence of infection 10 to 173 months after prosthetic graft placement were consecutively studied. The explanted Dacron or explanted polytetrafluoroethylene graft material was cultured in trypticase soy broth and ultrasonically oscillated to remove adherent bacteria. All patients were treated by excision of the pseudoaneurysm and surrounding perigraft capsule and in situ replacement with an interposition prosthetic graft. Thirty-two bacterial isolates were recovered from 27 (60%) of the specimens, with coagulase negative staphylococci (Staphylococcus epidermidis S. warneri, S. hominis, S. capitis) accounting for 24 of the recovered species. No infection of the replacement graft developed in any patient and no recurrent pseudoaneurysms were observed. Bacterial colonization may occur at implantation or during subsequent procedures when the prosthetic graft is exposed. This chronic infection can be diagnosed by means of sensitive culture techniques that dislodge adherent bacteria from the graft surface. On grounds of the observations reported in this study, there appears to be suggestive evidence that an occult infectious process may be one of the factors that play a role in the development of some femoral anastomotic pseudoaneurysms.

Aged↗