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Biomedical subjects

J P Carpenter

Publications and source records attributed to J P Carpenter.

At least 37 records · Page 2Linked to original sources
PubMed2000

Diagnosis and treatment of inferior mesenteric arterial endoleaks after endovascular repair of abdominal aortic aneurysms.

PURPOSE: To review the incidence and repair of inferior mesenteric arterial (IMA) type II endoleaks after endovascular repair of abdominal aortic aneurysms. MATERIALS AND METHODS: Fifty patients who underwent endovascular repair of abdominal aortic aneurysms were examined. If an endoleak was identified at 30-day postoperative computed tomography, conventional arteriography was performed to identify and eliminate its source. After the exclusion of attachment site leaks, a catheter was placed selectively in the superior mesenteric artery (SMA). If retrograde filling of the IMA and aneurysm was identified, coil embolization was attempted through the SMA and middle colic artery. Intrasac pressures were measured at embolization. RESULTS: Eight of 50 patients (16%) had type II endoleaks that were attributed to retrograde flow in the IMA. Intrasac measurements demonstrated systemic pressure in six patients and one-half systemic pressure in two patients. The IMA was embolized through the SMA and left colic artery in seven patients and through the translumbar aorta in one patient. CONCLUSION: Retrograde flow in the IMA is responsible for many type II endoleaks. Systemic pressures are transmitted into the aneurysm sac from the IMA. The IMA can be embolized successfully with an SMA approach in most patients.

Anastomosis, Surgical↗
PubMed1999

Perigraft air, fever, and leukocytosis after endovascular repair of abdominal aortic aneurysms.

BACKGROUND: The postimplantation syndrome of fever and leukocytosis after endovascular repair of infrarenal aortic aneurysms has not been previously characterized and its etiology is not known. METHODS: We studied the first 12 patients who underwent successful endovascular repair of infrarenal aortic aneurysms with Dacron-covered stent-grafts, as part of an ongoing phase II clinical trial. Sepsis syndrome evaluations (physical examination, urinalysis, chest radiograph, urine cultures, and blood cultures) were performed for all patients with postoperative temperature (T) greater than 101.4 degrees F. Computed tomography scans of the abdomen were performed, as part of the clinical protocol, on postoperative days 2 and 30. RESULTS: Fever (T > 101.4 degrees F) was seen in 8 of 12 (67%) patients (P < 05). An additional 2 of 12 (17%) patients had low-grade fevers (100.3 degrees F, 100.6 degrees F). Only 2 of 12 (17%) patients remained afebrile postoperatively. Leukocytosis with counts over 11,000 white blood cells (WBC)/dL was observed in 7 of 12 (58%) patients (P < 05). Sepsis evaluations failed to identify any source of infection in 11 of 12 (97%) patients. Computed tomography scan evidence of perigraft air was noted in 8 of 12 (67%) patients. All patients were afebrile, had normal white blood cell counts, and were discharged within 1 week postoperatively. There has been no evidence of graft infection after 1 to 6 months of follow-up. CONCLUSIONS: Fever and leukocytosis after stent-graft repair of aortic aneurysms does not represent evidence of systemic or graft infection and is not clearly related to nonspecific causes of postoperative fever and leukocytosis. Moreover, the finding of early postoperative perigraft air is not necessarily an indication of graft infection even when concurrently present with fever and leukocytosis.

Air↗
PubMed1999

Emergency repair of thoracoabdominal aortic aneurysms with immediate presentation.

OBJECTIVE: The objective of this report was the study of the clinical outcome of emergently repaired thoracoabdominal aortic aneurysms (TAAAs). METHODS: We retrospectively reviewed our experience with TAAA repairs from 1990 to 1998. During this interval, 110 TAAA procedures were performed, 33 (30%) of which were for immediate presentations. The chi(2) test and regression analysis were used for the analysis of mortality, paraplegia, and renal failure (hemodialysis) rates and of factors that predict these complications, respectively. RESULTS: There were no significant differences between the elective and immediate presentations with respect to the use of adjunctive procedures (lumbar drain, hypothermia, and bypass grafting). The overall mortality rate was 13%. There were no statistically significant differences between the 30-day mortality rates or the complication rates in elective versus immediate presentations. Subgroup analysis results showed a significantly higher in-hospital mortality rate in type II TAAA with immediate presentation and free rupture presentation as compared with the overall mortality rate (50% vs 13%, P <.05, and 67% vs 13%, P <.01, respectively). Multiple regression analysis results identified the use of bypass grafting (atrial-femoral or cardiopulmonary) and lumbar drain and shorter bypass grafting time as significant predictors of decreased overall mortality (P <.05). The mortality rates were not significantly different among aneurysm types and were not significantly decreased with the use of hypothermia. Paraplegia (5%) and renal failure (9%) rates were not predicted with aneurysm type, immediate versus elective presentation, or the adjunctive use of hypothermia, lumbar drain, or bypass grafting. CONCLUSION: The emergency repair of TAAA with immediate presentation can be performed with mortality and morbidity rates that approach those of elective presentations, except in the setting of free rupture or symptomatic type II TAAA. Adjunctive circulatory management techniques and lumbar drains may reduce mortality in TAAA repair.

Adult↗
PubMed1999

Decreasing carotid endarterectomy length of stay at a university hospital.

In 1995, a clinical pathway for carotid endarterectomy patients was instituted at the authors' institution. The effect of this program on length of stay and patient outcomes was investigated. Records of 152 consecutive carotid endarterectomies performed by a single surgeon over a 45-month period with identical technique (general anesthesia, routine shunting, closure with a dacron patch) were reviewed. Comparison of patients treated under the pathway (n = 119) and those prior to that policy (n = 33) revealed no significant differences (P>0.05) in age, sex, co-morbid conditions, or surgical indication. No difference (P>0.05) was found for occurrence of complications, which included two fatal perioperative strokes (1.3%) and two myocardial infarctions (1.3%) (one fatal). No complications occurred after discharge and no patients required readmission to the hospital. Average length of stay was reduced from 6.0 to 3.3 days, with 78% of patients discharged within 48 h. Preoperative hospitalization decreased from 100 to 21%. A decrease in the use of preoperative arteriography from 100 to 10% was noted. The cost of vascular studies decreased from $2451 to $1228. Cost-saving measures, including early discharge of stable patients, elimination of preoperative hospitalization and decreased use of arteriography, can be accomplished while maintaining acceptable complication rates following carotid endarterectomy in a university hospital setting.

Adult↗
PubMed1998

Local advancement flap for coverage of vascular anastomoses.

Outflow anastomoses of infrainguinal distal bypass grafts are often located beneath compromised skin wounds, which may dehisce leading to exposure of the distal graft anastomosis. Debridement of necrotic skin and flap coverage of the graft are standard remedial procedures for this complication. Very distal sites in the lower extremity offer few local muscle flap coverage options and may require free tissue transfer. We describe a simple local advancement flap technique that we have found to be successful without the need to perform free tissue transfer in the majority of cases.

Anastomosis, Surgical↗
PubMed1998

Magnetic resonance angiography of lower-extremity arterial disease.

Improvements in vascular technique have expanded the treatment options for patients with severe occlusive peripheral vascular disease. The decision to perform a major revascularization procedure in patients who are often at high risk for cardiovascular morbidity and mortality depends on the risk-benefit ratio. Detailed and accurate vascular imaging is essential and evaluating the likelihood of a successful revascularization with subsequent limb salvage. Although contrast angiography has been the time-honored reference standard imaging technique, the method is an invasive procedure with limitations and risks. MRA is a new, noninvasive vascular imaging technique that may now be added to the imaging options with the potential for improved sensitivity for finding patent runoff vessels, avoidance of morbidity, and cost equivalent to that of conventional contrast angiography. Magnetic resonance angiography is a rapidly developing and exciting new vascular imaging technique. As with any new technique, it is imperative that individual centers validate their MRA results and interpretations against the time-honored standard, which continues to be contrast arteriography. Several studies now indicate that MRA can be a cost-effective outpatient imaging technique sufficient for planning and successfully performing peripheral bypass procedures. As developments in hardware, software, and non-nephrotoxic contrast agents continue to increase, applicability of MRA in vascular surgery will continue to expand. Predictably, MRA will have a major role in the future of vascular imaging, and it is likely to supplant the need for conventional contrast angiography in the majority of patients.

Angiography, Digital Subtraction↗
PubMed1998

Endovascular surgery based solely on noninvasive preprocedural imaging.

PURPOSE: Conventional pre-endovascular procedural evaluation uses both noninvasive testing and diagnostic arteriography. Diagnostic and therapeutic procedures often must be performed separately because of concerns about excessive contrast administration or inappropriate location of vascular access for the interventional procedure. We wanted to determine if patients could successfully undergo endovascular procedures based on noninvasive modalities alone. METHODS: One hundred nineteen consecutive patients requiring intervention for lower-extremity ischemia were evaluated by means of physical examinations and segmental pressure measurements. Patients then underwent magnetic resonance angiography (MRA) to image native vessels or duplex scanning for failing bypass grafts. Suitable patients underwent endovascular procedures with "road map" arteriography, which was compared with preoperative duplex scanning or MRA findings. Costs of the conventional and noninvasive approaches were compared, on the basis of estimated hospital cost schedule. RESULTS: Sixty consecutive endovascular procedures were performed in 56 patients (105 lesions angioplastied), either alone (30, 50%) or in combination (30, 50%) with another vascular reconstruction. Completely noninvasive evaluation was accomplished in 43 procedures (72%), either by means of duplex scanning (11, 18%) or MRA (32, 53%). Conventional arteriography (CA) was required in 2 patients (3%) because of MRA contraindications and in 1 patient because of complex previous arterial reconstruction. Fourteen patients had earlier CAs. The findings of the noninvasive modalities were confirmed in every case by means of intraoperative arteriography, and no additional lesions were revealed (no false positive or negative studies). After endovascular interventions, the mean patient ankle-brachial index (ABI) improved from 0.64 +/- 0.03 to 0.81 +/- 0.03 (P <.001) and the mean limb-status category improved from 3.4 +/- 0.2 to 0.8 +/- 0.2 (P <.001). There were 4 initial technical failures (7%), 1 morbidity (1%), and no mortalities. The noninvasive approach was less costly than if preprocedural diagnostic CA had been used, allowing $551 saved for each duplex scanning case and $235 saved for each MRA case. If the cost of a short-stay unit after a diagnostic arteriogram was included, the savings were greater: $695 saved for each duplex scanning case and $379 saved for each MRA case. CONCLUSION: Endovascular procedures can be performed based on preprocedural noninvasive modalities alone. For patients requiring endovascular procedures, knowledge of the arterial anatomy before obtaining arterial access avoids the need for additional punctures or sessions (eg, antegrade puncture for femoral angioplasty after retrograde puncture for the diagnostic arteriogram). This approach is less costly than performing preprocedural diagnostic arteriography and avoids the hazards of arterial puncture and nephrotoxic contrast agents.

Aged↗
PubMed1998

Human saphenous vein allograft bypass grafts: immune response.

Although it has been claimed that allografts of blood vessels might be successful because of minimal immunogenicity, they are subject to frequent and early failure, the cause of which has not been thoroughly investigated. We sought to define the immune response to allograft bypass. In a prospective trial, 40 patients underwent cryopreserved venous allograft bypass. Allograft biopsies were performed at implantation and at allograft explantation in instances of graft failure. Tissues were evaluated in a blinded manner by means of standard histologic examination and paraffin immunohistochemical analysis with monoclonal antibodies against a variety of immune markers. During the 31-month follow-up period, 22 allografts were removed, and 19 were suitable for immunohistochemical study. Of these 19, 6 (32%) had moderate or severe infiltrates, which were evenly distributed throughout the intima, media, and adventitia. Immunohistochemical study of the explants demonstrated all of these infiltrates to be leukocytes (+LCA), which were predominantly activated T lymphocytes (+CD3, CD8, CR3) containing cytotoxic granules (+TIA-1). Macrophages were uncommon (+CD68); B cells (+L26, CD79) and natural killer cells (+CD56) were rare. Immunosuppression was associated with decreased presence of cytotoxic granules (TIA-1). Human venous allografts are immunogenic and prompt a T cell-mediated response. Allografts also fail without strong evidence of rejection, presumably because of local injury, hypercoagulability, or stasis. It may be possible to modify the contribution of rejection to venous allograft failure by means of immunosuppression and to modify the contribution of local hypercoagulability by means of anticoagulation.

Adult↗
PubMed1998

Cost-effectiveness of screening for asymptomatic carotid stenosis.

PURPOSE: The benefit of carotid endarterectomy for patients who are asymptomatic with > 60% carotid stenosis has been established by the Asymptomatic Carotid Atherosclerosis Study (ACAS). Which screening strategy is most appropriate is still unclear. This study assessed the cost-effectiveness of ultrasound screening for asymptomatic carotid stenosis. METHODS: Cost-effectiveness analysis was performed with a Markov model and with data from ACAS and other studies. RESULTS: For 60-year-old patients with a 5% prevalence of 60% to 99% asymptomatic stenosis, duplex ultrasound screening increased average quality-adjusted life years (QALY; 11.485 vs 11.473) and lifetime cost of care ($5500 vs $5012) under base-case assumptions. The incremental cost per QALY gained (cost-effectiveness ratio) was $39,495. Screening was cost-effective with the following conditions: disease prevalence was 4.5% or more, the specificity of the screening test (ultrasound) was 91% or more, the stroke rate of patients who were medically treated was 3.3% or more, the relative risk reduction of surgery was 37% or more, the stroke rate associated with surgery was 160% or less than that of the North American Symptomatic Carotid Endarterectomy Trial or ACAS perioperative complication rates, and the cost of ultrasound screening was $300 or less. A one-time screening, compared with a screening every 5 years, had more QALY (11.485 vs 11.482) and lower cost ($5500 vs $5790). Screening without arteriography, compared with screening with arteriographic verification, provided few additional QALYs (11.486 vs 11.485) at additional cost ($6896 vs $5500). The cost-effectiveness ratio was sensitive to assumptions about the stroke rate of patients who were asymptomatic and other variables. CONCLUSIONS: Screening for asymptomatic carotid stenosis can be cost-effective when both screening and carotid endarterectomy are performed in centers of excellence.

Carotid Stenosis↗
PubMed1998

Extracranial atherosclerotic carotid artery disease: evaluation of non-breath-hold three-dimensional gadolinium-enhanced MR angiography.

OBJECTIVE: The purpose of this study was to compare the diagnostic information provided by a combination of two-dimensional and three-dimensional (3D) time-of-flight (TOF) techniques with that provided by non-breath-hold 3D spoiled gradient-echo gadolinium-enhanced MR angiography. MATERIALS AND METHODS: Fifty patients suspected of having extracranial atherosclerotic carotid artery disease were examined with all three imaging techniques using a 1.5-T MR imaging system. Three observers independently and retrospectively measured the degree of stenosis according to the North American Symptomatic Carotid Endarterectomy trial criteria. The observers were unaware of the results of other MR imaging pulse sequences and digital subtraction angiography. The standard of reference was established by digital subtraction angiography. Results were evaluated with receiver operating characteristic curve analysis. The degree of interobserver agreement was determined using pairwise kappa statistics. RESULTS: The grading of carotid artery stenosis as measured by the area under the receiver operating characteristic curve was less accurate with non-breath-hold 3D gadolinium-enhanced MR angiography than with TOF imaging. Interobserver variability was greater for non-breath-hold 3D gadolinium-enhanced MR angiography than for TOF techniques. CONCLUSION: Routine evaluation of carotid artery stenosis at the level of the bifurcation using non-breath-hold 3D gadolinium-enhanced MR angiography is less accurate than is TOF imaging and is therefore not recommended. The weakness of this technique may be due to problems in timing the injection of gadolinium and the masking of the carotid bifurcation by the venous jugular system.

Aged↗
PubMed1997

Immunosuppression for human saphenous vein allograft bypass surgery: a prospective randomized trial.

PURPOSE: Vein allografts are an alternative bypass conduit for patients who lack adequate autogenous vein. Animal studies have demonstrated that patency can be augmented by low-dose immunosuppression with azathioprine. METHODS: In a prospective trial, 40 patients (20 men, 20 women) were randomly assigned to receive (17) or to not receive (23) azathioprine (1 mg/kg/day) after cryopreserved vein allograft bypass grafting. Patients had pain or tissue loss that required bypass grafting to pedal or crural outflow and lacked adequate autogenous saphenous vein. Anti-HLA antibody screens were obtained before and after surgery. Biopsies of allografts were performed at implantation and at all subsequent opportunities. Postoperative physical and vascular laboratory examinations occurred every 3 months. RESULTS: During the 31-months follow-up interval (mean, 15.7 months) there were 10 deaths (none immunosuppression-related). The primary graft patency rate at 12 months was 13%, and the limb salvage rate was 42%. No significant difference (p > 0.05) was noted between immunosuppressed and control groups for mortality rate, primary graft patency rate, or limb salvage rate. As a predictor of graft failure, positive preoperative anti-HLA antibody screen (8 patients) approached significance (p = 0.09). Of 22 explanted grafts, 13 (59%) had histologic evidence of rejection (six immunosuppressed, seven control). Seven patients who had negative results of preoperative anti-HLA antibody screens converted after surgery, and six patients had positive results of preoperative screens that became more strongly positive. CONCLUSION: Vein allograft failure is in part mediated by rejection, which is not eliminated by low-dose azathioprine. Both humoral (antibody) and cellular responses to vein allografts develop. The poor patency rates of vein allograft bypass grafts may be improved by more potent immunosuppression as well as improvement in allograft procurement, preservation, and matching.

Aged↗
PubMed1997

Upper abdominal aortic injury during spinal surgery.

We describe a rare case of iatrogenic injury to the upper abdominal aorta during spine surgery. The case is reviewed, and diagnosis as well as management of this injury is discussed. No similar previous reports of iatrogenic injury to the upper abdominal/lower thoracic aorta were identified in the literature. Reports of iatrogenic injury to the lower abdominal aorta during spinal surgery have been frequent. With more aggressive operative treatment of spinal disorders, injury to the upper abdominal/lower thoracic aorta may become more common. Timely diagnosis and treatment are essential to prevent both early and delayed complications and death.

Aged↗
PubMed1997

Magnetic resonance angiography of the aortic arch.

Duplex ultrasound and magnetic resonance angiographic (MRA) studies are the principal noninvasive methods for evaluation of extracranial occlusive disease in patients at risk for stroke, but each has limited ability to diagnose aortic arch and arch vessel disease. Recent favorable reports of the nonnephrotoxic contrast agent Gadolinium (Gd) being used to enhance MRA images of the abdominal aorta prompted us to examine its utility for the aortic arch vessels. Prospectively, 28 patients with suspected carotid or arch vessel disease were imaged by contrast arteriographic examination and MRA + Gd of the aortic arch within 30 days of each other. One (for contrast arteriograms) or two (for MRA) blinded readers measured stenoses with the contrast arteriograms as the standard. A total of 196 arch vessels containing 58 stenoses and four occlusions (by arteriogram) were examined with each method. Interobserver agreement for interpretation of MRA studies was substantial (kappa = 0.68). MRA detected all anatomic anomalies (e.g., bovine arch). The correlation of MRA with arteriographic scans for arch vessel stenoses > 50% was sensitivity, 73% (readers 1 and 2); specificity, 98% (reader 1), 89% (reader 2); positive predictive value, 73% (reader 1), 89% (reader 2); negative predictive value, 98% (readers 1 and 2); accuracy, 97% (reader 1), 98% (reader 2). MRA + Gd is an accurate new noninvasive imaging method for detection of significant aortic arch disease. In its current state of development, however, it cannot obviate the need for contrast arteriographic examination.

Aorta, Thoracic↗
PubMed1996

The fate of bypass grafts to angiographically occult runoff vessels detected by magnetic resonance angiography.

PURPOSE: Magnetic resonance angiography (MRA) is a noninvasive vascular imaging technique that is more sensitive than contrast arteriography (CA) for the detection of patent distal runoff vessels. This technique has facilitated performance of MRA-directed bypass procedures for patients who were believed not to be bypass candidates because of the absence of a suitable target vessel on the preoperative CA. The fate of bypasses to these angiographically occult runoff vessels is unknown, however, and it has been proposed that patients with angiographically occult runoff may have aggressive occlusive disease, rendering bypass procedures ultimately futile. METHODS: Between April 1992 and February 1995, 212 autogenous vein infrageniculate bypasses were performed for limb-salvage indications, 22 (12%) to angiographically occult runoff vessels. Results of bypasses performed to angiographically occult vessels were compared with those of bypasses to CA-detected runoff vessels. Life-table analysis of graft-patency and limb-salvage rates was performed. RESULTS: The accuracy of the MRA-predicted patency of angiographically occult vessels was confirmed in every case by the operative findings. Life-table analysis revealed no significant difference in primary graft patency (p > 0.05) or limb-salvage (p > 0.05) rates between patients with bypasses to runoff vessels seen by MRA alone. At 35 months after surgery, the primary graft patency rate was 68% for bypasses to CA-detected vessel bypass and 67% for MRA-detected vessels. The limb salvage rate was 83% for CA-detected vessel bypass patients and 78% for patients with angiographically occult runoff. CONCLUSIONS: MRA can accurately identify patent runoff vessels not visualized by CA. Results of bypasses performed to angiographically occult runoff vessels are similar to those of bypasses performed to vessels detected by CA. MRA should be performed in patients in whom CA fails to reveal runoff vessels suitable for use in a limb-salvage procedure. The greater sensitivity of MRA may facilitate successful bypass surgery and improve the overall limb-salvage rate.

Aged↗
PubMed1996

Determination of duplex Doppler ultrasound criteria appropriate to the North American Symptomatic Carotid Endarterectomy Trial.

BACKGROUND AND PURPOSE: The North American Symptomatic Carotid Endarterectomy Trail (NASCET) demonstrated the benefit of carotid endarterectomy for symptomatic patients with > or = 70% carotid stenosis. Screening for detection of significant carotid occlusive disease has relied on duplex Doppler imaging. However, traditional duplex categories (50% to 79%, 80% to 99%) are not directly applicable to NASCET. We sought to evaluate duplex criteria for determination of > or = 70% carotid stenosis. METHODS: Duplex scan and arteriograms of 110 patients (210 carotids), performed within 1 month of each other, were reviewed by blinded readers. Arteriographic stenosis was determined by the NASCET method. Duplex measurements of peak systolic and end-diastolic velocity (PSV, EDV) were recorded, and ratios of velocities in the internal and common carotid arteries (ICA, CCA) were calculated. Receiver-operator characteristic (ROC) curves of sensitivity, specificity, positive and negative predictive values (PPV, NPV), and accuracy were determined. RESULTS: Interobserver agreement for measurement of arteriographic stenosis was "almost perfect" (kappa=0.86). The criteria chosen for detection of > or = 70% stenosis were PSVICA>210 cm/s (sensitivity, 94%; specificity, 77%; PPV, 68% NPV, 96% accuracy, 83%) EDVICA>70 cm/s (sensitivity, 92%; specificity, 60%; PPV, 73%; NPV, 86%; accuracy 77%), PSVica/PSVCCA >3.0 (sensitivity, 91%; specificity, 78%; PPV, 70%; NPV, 94%; accuracy, 83%), and EDVICA/EDVCCA>3.3 (sensitivity, 100%; specificity, 65%; PPV, 65% NPV, 100%; accuracy, 79%). CONCLUSIONS: We conclude that > or = 70% carotid stenosis can be reliably determined by duplex Doppler ultrasound. Individual vascular laboratories must validate their own results.

Carotid Artery, Common↗
PubMed1996

Breath-hold ultrafast three-dimensional gadolinium-enhanced MR angiography of the aorta and the renal and other visceral abdominal arteries.

OBJECTIVES: The objectives of this study were to develop and show the efficacy of a breath-hold ultrafast three-dimensional (3D) spoiled gradient-echo (SPGR) gadolinium-enhanced MR angiographic technique for imaging the aorta and the renal and other visceral arteries of the abdomen; and to compare breath-hold ultrafast 3D SPGR with two-dimensional (2D) time-of-flight (TOF) and non-breath-hold ultrafast 3D SPGR in the same patients. SUBJECTS AND METHODS: We prospectively studied the abdominal aorta and the renal and other visceral arteries 68 times in 63 consecutive patients with 2D TOF and ultrafast 3D SPGR MR angiography. Thirty-two patients had contrast angiography (n = 23) and/or surgery (n = 24) to serve as a gold standard. All MR imaging studies were performed on a 1.5-T scanner (General Electric Medical Systems, Milwaukee, WI) using an enhanced gradient system with maximum gradient strength of 2.3 gauss/cm reached in 150 microseconds. Axial 2D TOF parameters were: TR/TE, 33/5.5 msec; flip angle, 45 degrees; slice thickness, 2 mm; and no presaturation pulses. Coronal ultrafast 3D SPGR was performed before and after the i.v. administration of 40-60 cc of gadolinium. For the coronal ultrafast 3D SPGR, our parameters were: TR/TE, 4.8-7/1.1; flip angle, 60 degrees; 28-50 slices of 2.0-2.6 mm thickness; and acquisition time, 18-32 sec. Studies were read by a single radiologist [corrected] and were evaluated for the degree of stenosis in the renal, celiac, superior mesenteric, and inferior mesenteric arteries; any vascular anomalies (i.e., retroaortic renal veins and accessory renal or variant hepatic arteries) were noted. RESULTS: Breath-hold ultrafast 3D SPGR correctly identified 31 of 31 stenoses of the renal artery for a sensitivity, specificity, and accuracy of 100%. Two-dimensional TOF detected 23 of 31 renal artery stenoses for a sensitivity, specificity, and accuracy of 74%, 98%, and 87% respectively. Breath-hold ultrafast 3D SPGR underestimated two renal arteries as having severe osteal stenoses that were graded correctly by 2D TOF and by angiography as occlusions. Eight of nine (89%) accessory renal arteries were correctly identified with breath-hold ultrafast 3D SPGR: Two-dimensional TOF identified six of nine (67%). Breath-hold ultrafast 3D SPGR identified one accessory and two reconstituted renal arteries missed by 2D TOF and conventional contrast angiography that were confirmed at surgery. Ultrafast 3D SPGR and 2D TOF correctly identified 20 of 20 celiac, superior mesenteric, and inferior mesenteric artery osteal stenoses or occlusions for a sensitivity, specificity, and accuracy of 100%. Three Riolan's arcs were correctly identified by breath-hold 3D SPGR but were missed by 2D TOF: Forty of the 63 patients did not have conventional contrast angiography and were managed surgically (n = 9) or medically (n = 31) based on the results of the MR angiograms and clinical data. Breath-hold ultrafast 3D SPGR MR angiography correctly identified and graded 48 of 51 renal, celiac, superior mesenteric, and inferior mesenteric artery stenoses or occlusions. Two-dimensional TOF MR angiography correctly identified and graded 45 of 51 renal, celiac, superior mesenteric, and inferior mesenteric artery stenoses and occlusions. CONCLUSION: Breath-hold ultrafast 3D SPGR when combined with 2D TOF accurately identified and graded all (51 of 51) renal, celiac, superior mesenteric, and inferior mesenteric artery stenoses or occlusions.

Adolescent↗
PubMed1996

Intraoperative urokinase as an alternative to heparin for patients with suspected heparin-induced thrombocytopenia requiring arterial reconstruction: report of a case and review of the literature.

Patients with heparin-induced thrombocytopenia (HIT) require an alternative antithrombotic treatment to heparin during arterial reconstruction. Ancrod and Iloprost have been employed but are not readily available and carry the risks of systemic side effects (depletion of fibrinogen, hypotension). A patient with HIT in whom intraoperative intraarterial urokinase (UK) was successfully utilized to enable safe arterial reconstruction is described. An 80 year old white female with diffuse arteriosclerotic cardiovascular disease and multiple vascular reconstructions had thrombotic complications following use for heparin during two of her prior operations associated with documented thrombocytopenia and anti-platelet antibodies. She presented with limb-threatening ischemia which was evaluated with angiography revealing severe stenosis of the proximal left superficial femoral artery, occlusion of both anterior tibial and peroneal arteries and several digital vessels, with intact posterior tibial runoff. A common femoral to mid-superficial femoral artery bypass was performed, utilizing contralateral reversed greater saphenous vein, while being treated with aspirin and a continuous intravenous infusion of low molecular weight dextran. During the procedure the clamped arteries were locally perfused with a high volume of dilute UK solution to prevent blood stasis, and enable local delivery of a thrombolytic agent. Although clot formation was observed in the operative field, none occurred within the clamped arteries. A total of 191,200 units of UK were employed with no bleeding complications. Following surgery the patient had a palpable pedal pulse and markedly improved perfusion of her toes. She was discharged on aspirin and coumadin on postoperative day five. It is concluded that for patients with HIT, systemic aspirin and dextran combined with local intraarterial UK are a simple and effective substitute for systemic anticoagulation with heparin during arterial reconstruction.

Aged↗