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Biomedical subjects

D F Bandyk

Publications and source records attributed to D F Bandyk.

107 records · Page 6Linked to original sources
PubMed1984

Detection of technical error during arterial surgery by pulsed Doppler spectral analysis.

Pulsed Doppler spectral analysis of midstream flow was compared with arteriography in 90 patients following carotid endarterectomy (N = 60) or lower-extremity bypass grafting (N = 30) for the detection of unsuspected technical error. Spectral changes in the velocity waveform indicating flow disturbance were identified in the endarterectomy or anastomotic sites of 11 patients (12%). All were associated with an anatomic defect apparent on arteriography. The revision of major defects in six patients (7%) corrected the flow disturbance. The absence of flow disturbance in 79 patients (88%) predicted a technically satisfactory arterial reconstruction. Intraoperative assessment by pulsed Doppler spectral analysis is a noninvasive, rapid, and accurate method for detecting technical errors during arterial surgery. The high sensitivity of this method makes it suitable for use as a screening test, resulting in the selective use of operative arteriography.

Angiography↗
PubMed1984

Intravenous DSA examination of patients with suspected cerebral ischemia.

We analyzed the role of intravenous digital subtraction angiography (DSA), with neck and intracranial views as a definitive pretherapy study, in patients who had symptomatic cerebral ischemia. Eighty-six patients, 25 of whom had subsequent carotid thromboendarterectomy, were examined. An adequate pretherapy intravenous DSA study allowed us to define each carotid bifurcation as either normal, having insignificant stenosis, or having significant stenosis, and the examination excluded significant tandem stenosis in the intracranial internal carotid arteries. Adequate pretherapy intravenous DSA studies were obtained in 73% of patients, including 50% of those in the presurgical group. Selective carotid arteriography was not required in these patients. Inadequate presurgical studies were predominantly due to plaque misregistration, inadequate projection, and superimposition that obscured the proximal internal carotid arteries. Selective carotid arteriography was performed in these patients prior to surgery. Inadequate studies prior to initiation of medical therapy were predominantly due to soft tissue misregistration artifact, and superimposition. Intravenous DSA is a valuable screening test and can be used to guide therapy in the majority of patients who have symptomatic cerebral ischemia.

Arterial Occlusive Diseases↗
PubMed1984

Abnormal plasminogen: a genetically determined cause of hypercoagulability.

An inherited disorder of the fibrinolytic system has been discovered as a cause of unusual clotting. An abnormal immunoreactive plasminogen was identified in eight patients who presented with unexplained thrombosis. Six patients presented with spontaneous arterial or venous thrombosis, and two patients developed postoperative occlusion of an arterial reconstruction. Five of the six patients with spontaneous thrombosis had recurrent episodes involving both the arterial and venous system at time intervals between the thrombotic episodes varying from 1 month to several years. Detection of an abnormal plasminogen was made by immunoelectrophoresis of the patient's serum with an antiplasminogen sera. In normal patients, plasminogen migrates as a single band toward the anode. In these eight patients a separate immunoreactive band located nearer the anode and distinct from the normal band was detected. Examination of family members of two patients identified a similar abnormal plasminogen with an overall incidence suggestive of an autosomal dominant inheritance pattern. This study suggests the presence of a genetically determined plasminogen variant resulting in a functional deficiency of the plasminogen system causing a reduction of fibrinolytic activity and a latent thrombotic tendency. Recommended treatment is long-term warfarin anticoagulation.

Adult↗
PubMed1984

Intraoperative assessment of carotid endarterectomy.

The use of operative arteriography during carotid endarterectomy facilitates identification and correction of technical errors. Although arteriography is the standard for assessing surgical results, it prolongs the operation and may increase the overall risk. The purpose of this study was to evaluate pulsed Doppler spectral analysis and arteriography as methods of intraoperative assessment. Operative arteriography was performed in 150 consecutive carotid endarterectomies. In 50 of these cases a sterile 20 MHz pulsed Doppler probe and real-time spectrum analyzer were used to evaluate internal carotid velocity patterns before and after endarterectomy. Operative arteriograms were normal in 127 cases, whereas abnormalities were noted in 16 internal and seven external carotid arteries. Thirteen of the arteriographic defects were considered minor and accepted. Major defects requiring immediate repair occurred in eight (5%) internal and two external carotid arteries. In the 50 cases assessed by both techniques, seven internal carotid arteries had mild flow disturbances both before and after endarterectomy, whereas 38 of the remaining 43 arteries showed improvement in spectral characteristics after endarterectomy. In two patients who failed to show improvement on the initial postendarterectomy evaluation, operative arteriography demonstrated residual defects that required immediate repair. No other technical errors were encountered, and there were no perioperative deaths or neurologic complications in the 150 operations. Intraoperative assessment by pulsed Doppler spectral analysis is a safe, rapid, and accurate method for detecting technical errors during carotid endarterectomy. The high sensitivity of this method (no false negative assessments) makes it an ideal screening test to be used for selection of patients for operative arteriography. By indicating when a technical error is most likely, this approach precludes the need for routine operative arteriography.

Arterial Occlusive Diseases↗
PubMed1983

A systematic approach to the assessment of aortoiliac disease.

The accurate localization of hemodynamically significant disease in the aortoiliac segment remains a major clinical dilemma that contributes to the less than optimal results reported for aortofemoral bypass grafting in patients with disabling lower limb claudication. We assessed the hemodynamic status of the aortoiliac segment with direct intraarterial pressure measurements obtained prior to arteriography. This served as a basis for determining the role of the femoral pulsatility index (FPI) in evaluating the hemodynamics of the aortoiliac segment. A stepwise decision making algorithm, developed from the results, enabled accurate identification of the location of the hemodynamic disturbance in 94% of the limbs studied. In 62% of the limbs, the FPI could be used, while in the remaining 38%, intra-arterial pressure measurements were used.

Aorta, Abdominal↗
PubMed1983

Streptokinase treatment of acute arterial occlusion.

In selected cases, streptokinase, a thrombolytic agent, is an effective alternative to surgical intervention for the treatment of acute arterial occlusions. Successful thrombolysis was achieved in 12 of 16 arterial occlusions (75%) following the intra-arterial infusion of streptokinase at a dosage of 5,000 U per hour. Neither the etiology nor the duration of the occlusions influenced the ability to achieve effective thrombolysis. The major limitation of the technique was the time required to ensure complete thrombolysis (37.5 +/- 17.5 hours). Despite the localized infusion of streptokinase proximal to the arterial obstruction at low dosages, hypofibrinogenemia (100 mg/dl) occurred in five patients and four patients developed a bleeding complication. The use of concomitant heparin (300-500 U per hour) increased the risk of bleeding without increasing thrombolytic potential. Streptokinase treatment of acute arterial occlusions should be used selectively depending on the degree of ischemia, the etiology of the obstruction, and the clinical status of the patient.

Aged↗
PubMed1983

Noninvasive assessment of carotid artery disease.

Noninvasive methods of detecting carotid disease were developed to avoid the morbidity and occasional mortality associated with cerebral angiography. The tests developed are of the following two types: direct, which uses imaging or the detection of flow disturbances to identify disease at the bifurcation, and indirect, which infers the presence of bifurcation disease by detecting changes at a remote site. The initial goal of only detecting disease has now been broadened, with this technology being used to address important clinical and epidemiologic questions such as the natural history of carotid bifurcation disease. The recognition of these important contributions has been compounded, however, by the large number of tests that are available, producing the problem of deciding which test or tests should be used for a particular patient. The use of multiple tests avoids the deficiencies of single tests but compounds medical costs. For a cost-effective single form of testing for all circumstances, duplex scanning methods offer the greatest possibility of detecting all degrees of disease.

Angiography↗
PubMed1983

Safe intraluminal shunting during carotid endarterectomy.

The major complications associated with shunting include embolization at the time of insertion and shunt thrombosis. Increased technical difficulty of performing the endarterectomy with an inlying shunt hs also contributed to lack of surgeon acceptance. These problems can be minimized by using a short, flexible shunt with a sidearm attachment. The shortness enables the shunt to lie within the vessel, while the flexibility enables manipulation of the shunt to optimize exposure of all segments of the vessel. The sidearm allows flushing of both limbs and helps prevent embolization while providing a means for rapid assessment of shunt patency. The technique provides a safe and simple method of shunting during carotid endarterectomy.

Carotid Arteries↗
PubMed1982

Carotid artery stenosis following endarterectomy.

Duplex scanning and spectral analysis were used to detect carotid artery stenosis following 89 endarterectomies in 76 patients with a mean postoperative follow-up interval of 16 months. Operative arteriography was used in all cases to verify the technical result. Spectral changes indicating greater than 50%-diameter internal carotid stenosis were observed postoperatively in 32 of the 89 sides. Serial follow-up of 22 stenotic sides showed persistent stenosis in 12, regression of stenosis in nine, and internal carotid occlusion in one. The estimated overall incidence of persistent high-grade stenosis was 19%. Recurrent neurologic symptoms occurred in eight patients. This incidence of postoperative carotid stenosis is higher than estimates based on clinical criteria. The transient nature of some early postoperative stenosis is consistent with proliferation and regression of myointimal lesions in response to arterial injury.

Carotid Arteries↗
PubMed1982

Role of intraoperative pancreatography in patients with injury to the pancreas.

Over a 10 year period, 54 patients presented with pancreatic trauma. During the first 5 years of the study, when pancreatography was not utilized for the assessment of pancreatic duct injury, 55 percent of the patients had major pancreatic complications. During the subsequent 5 years, suspected proximal duct injury was evaluated by intraoperative pancreatography. This resulted in a decrease of postoperative morbidity to 15 percent. In addition, there were not postoperative deaths during this period. The reduction in adverse sequelae after pancreatic trauma leads us to support the following principles of treatment: early recognition of pancreatic injury with immediate surgical intervention, complete exploration of the pancreas with the liberal use of intraoperative pancreatography to determine the presence of major duct injury, and the use of techniques which ensure control of duct disruption.

Abdominal Injuries↗
PubMed1981

Upper-extremity emboli secondary to axillofemoral graft thrombosis.

Four episodes of upper-extremity arterial emboli following axillofemoral bypass graft thrombosis are described. The source of the embolus was the blind stump of the proximal portion of the graft limb that remained patent after graft occlusion. With axillofemoral graft thrombosis, management requires treatment of the lower-limb ischemia and an awareness of the embolic potential of the acutely thrombotic graft limb. Patient evaluation and the surgical management of axillofemoral graft thrombosis with and without the complication of upper-extremity ischemia are discussed, as well as the etiology and prevention of this complication.

Arm↗
PubMedDate not supplied

Intraoperative pulsed Doppler assessment of carotid endarterectomy.

A 20 MHz pulsed Doppler velocimeter and fast Fourier transform spectrum analyzer were used at operation to assess the velocity patterns just prior to and immediately following carotid endarterectomy (TEA). In all 45 sides studied, the status of the endarterectomized segment was verified by operative arteriography. Corresponding Pre-TEA and Post-TEA internal carotid artery spectra were compared to each other and classified according to criteria developed using the ultrasonic Duplex scanner. Of 39 arteries with significant Pre-TEA flow disturbances, improvement in Post-TEA spectral characteristics was observed in 35, and 4 were not changed. Six arteries had only minimal flow disturbances both before and after endarterectomy. In one case the initial Post-TEA spectrum showed a worsening of the flow disturbance which was found on operative arteriography to be due to a stenosis secondary to a technical error. After vein patch angioplasty, the spectrum and repeat arteriogram were both improved. No other significant technical problems were encountered. Although the velocity patterns were improved by endarterectomy in most cases, some residual flow disturbance often remained. Technical factors were not a major cause of the Post-TEA flow disturbances. Lack of improvement or deterioration in the spectra after closure of the arteriotomy may be useful in selecting patients for operative arteriography. Intraoperative spectra also provide important baseline data for long term followup studies.

Blood Flow Velocity↗
PubMedDate not supplied

Pulsed Doppler velocity patterns produced by arterial anastomoses.

Centerstream velocity waveforms produced by end-to-end and end-to-side anastomoses constructed in the dog illeofemoral arterial system were studied with a 20 MHz pulsed Doppler velocimeter combined with spectral analysis. Flow disturbance was identified by changes in spectral width during the systolic phase of the cardiac cycle. Measurement of the maximum frequency and the spectral width at peak systole was used to quantify the magnitude of flow disturbance at varying locations proximal and distal to the anastomoses. Disruption of the normal laminar flow pattern observed in the unoperated dog artery was evident distal to both anastomotic configurations. An increase in spectral width reflecting disturbed flow was maximal during the deceleration phase of systole. Flow disturbance was localized to a zone within one diameter distal to the anastomosis and dissipated rapidly downstream. The velocity spectrum changes observed downstream of an anastomosis resemble the flow disturbances produced by low grade, nonpressure reducing arterial stenoses. This study suggests that spectral analysis of pulsed Doppler waveforms is a potentially useful method of anastomosis assessment both to rule out major flow disruption produced by technical error, and to provide insight into the role of turbulence in the development of anastomotic intimal hyperplasia.

Animals↗
PubMedDate not supplied

Primary axillary-subclavian venous thrombosis: is aggressive surgical intervention justified?

Multimodal (thrombolysis, surgical decompression, venous reconstruction, oral anticoagulation) treatment of primary axillary-subclavian venous thrombosis was reviewed to assess the impact of venous patency on functional outcome. Since 1996, 7 patients (6 men, 1 woman) of ages 16-53 years (mean 33 years) presented with symptomatic acute axillosubclavian venous thrombosis as a result of a recent athletic or strenuous arm activity. Five patients had undergone previous (>2 weeks) catheter-directed thrombolysis and venous angioplasty. Diagnostic contrast venography followed by repeat catheter-directed thrombolysis demonstrated abnormal (residual stenosis [n=6] or occlusion [n=1]) axillosubclavian venous segments in all patients. Surgical intervention was performed at a mean interval of 7 days (range 1-19 days) after thrombolysis and consisted of thoracic outlet decompression with scalenectomy and 1st rib resection via a paraclavicular (n=4) or supraclavicular (n=3) approach. Medial claviculectomy or cervical rib resection was performed in 2 patients. Concomitant venous surgery was performed in all patients to restore normal venous patency by circumferential venolysis (n=7) and balloon catheter thrombectomy (n=3), or vein-patch angioplasty (n=2), or endovenectomy (n=5), or internal jugular transposition (n=2). Postoperative venous duplex testing beyond 1 month identified recurrent thrombosis in 4 patients despite therapeutic oral anticoagulation. Subsequent venous recanalization was documented in 3 patients. Poor functional outcome was associated with an occluded venous repair and extensive venous thrombosis on initial presentation. A patent or recanalized venous repair present in 6 of 7 patients was associated with good functional outcome and may justify multimodal intervention in patients with primary axillosubclavian effort thrombosis presenting with recurrent thrombosis and significant residual disease after thrombolysis.

Adolescent↗
PubMedDate not supplied

The effect of vein diameter on patency of in situ grafts.

In an attempt to evaluate the effect of vein diameter on early patency and long-term durability of in situ lower limb bypasses, we evaluated 195 femoral-distal, popliteal, and/or tibial bypasses constructed in 189 patients (153 men, 36 women), consisting of tibial bypasses in 116 (60%), and popliteal in 79 (40%). The operative angiograms were reviewed and the vein diameter was measured to the nearest 0.5 mm. Postoperative follow-up consisted of visits every three months where graft patency was assessed by physical examination and measurement of graft flow velocity and ankle-brachial indices. Conduits less than 3 mm had a higher rate of occlusion in the 0-30 day interval, but following that period performed satisfactorily. No conduit less than 2 mm was successfully utilized, because of inability to incise valves without injury in these tiny conduits. Following the perioperative period, conduit diameter does not affect the long-term durability of in situ bypass grafts.

Blood Vessel Prosthesis↗
PubMedDate not supplied

Graft excision and extra-anatomic revascularization: the treatment of choice for the septic aortic prosthesis.

Graft excision and extra-anatomic revascularization is the treatment of choice for the septic aortic prosthesis. From 1979 to 1988, 20 patients underwent resection of aortic grafts and extra-anatomic bypass for the treatment of graft infections (No. 11) and aorto-enteric fistulas (No.9). The mean time interval from primary aortic surgery to the reoperative procedure was 65 months (range 1-192 months). Three patients died (one less than 30 days) after the secondary procedure for a mortality rate of 15%. One patient developed infection of the extra-anatomic bypass graft which resulted in an above-knee amputation. This was the only major limb loss in this series. A second patient developed contralateral buttock necrosis when he had unilateral axillary-femoral bypass without femoral-femoral bypass because of a previous above-knee amputation on the affected side. Major complications occurred in 7 patients (35%). Mean duration of follow-up after the reoperative aortic procedure was 44 months (range 6-120 months). One patient suffered aortic stump blowout 7 months after repair of an aortic duodenal fistula. Aortic graft excision and extra-anatomic revascularization of the lower extremities can be performed with low mortality and risk of limb loss and should remain the treatment of choice for aorto-enteric fistulas and infected aortic prostheses. Bilateral groin revascularization is important even in patients who have had a previous lower extremity amputation to provide pelvic blood flow.

Aged↗