PREVALENCE AND MOLECULAR CHARACTERIZATION OF DIROFILARIA IMMITIS (FILARIOIDEA: ONCHOCERCIDAE) IN DOGS FROM ENDEMIC AREAS OF RIO DE JANEIRO STATE, BRAZIL.

Canine dirofilariasis is common in Brazil, but molecular diagnosis is rare even though molecular studies increase our knowledge about molecular epidemiology and circulating genotypes from helminths worldwide. This study aims to estimate the prevalence of infection with a modified Knott's test and to perform molecular characterization of Dirofilaria immitis (Leidy, 1856) Railliet and Henry, 1911, in dogs from endemic areas of Maricá and Niterói municipalities, Rio de Janeiro State, Brazil. Molecular characterization was performed in 33 blood samples from dogs positive for microfilariae and 4 adult worms obtained from 2 other dogs. DNA extraction followed by PCR for mitochondrial target 12S rDNA and cytochrome oxidase subunit 1 (COI) of D. immitis were performed, and the amplified products were sequenced. All sequences were identical for both gene targets and showed 100% identity with D. immitis sequences from different animal species from various countries. The study concluded that this genotype of D. immitis might be dispersed worldwide.

Cheilospirura hamulosa (Diesing, 1851) (Nematoda, Acuarioidea) in turkeys in Brazil: occurrence and pathology

Relata-se o primeiro caso de infecção de perus, Meleagris gallopavo, por Cheilospirura hamulosa no Brasil, com base no achado de três espécimes fêmeas de C. hamulosa, inseridos na submucosa da moela de um peru, retirado de um lote de 15 aves, provenientes de criadouros domésticos no estado de Minas Gerais. A ocorrência foi de 6,7 por cento. A ave parasitada não apresentava sinais clínicos. As lesões microscópicas da moela eram severas, caracterizando-se por intensos processos inflamatórios crônicos e difusos, com infiltrados mistos de granulócitos, estendendo-se à mucosa e às camadas musculares. Nessa área, foram observados fragmentos dos parasitos e perfuração da mucosa, com destruição das camadas musculares.

Frequência de enteroparasitas em amostras fecais de cães e gatos dos municípios do Rio de janeiro e Niterói / Frequency of enteric parasites in fecal samples of dogs and cats in Rio de Janeiro and Niterói

Foram analisadas 252 amostras de fezes de cães e gatos provenientes dos municípios do Rio de Janeiro e Niterói no período de 1999 a 2000. Foram 212 (84,12

Freqüência de enteroparasitas em amostras fecais de cães e gatos dos municípios do Rio de Janeiro e Niterói

Foram analisadas 252 amostras de fezes de cães e gatos provenientes dos municípios do Rio de Janeiro e Niterói no períodode 1999 a 2000. Foram 212 (84,12%) amostras de cães e 40 (15,87%) de gatos. Do total de amostras examinadas 81(32,14%), foram positivas para pelo menos uma espécie de parasita. Dos 212 exames de material fecal canino, 70 (33,01%)estavam positivos e de felinos 11 (27,5%). As infecções mistas foram observadas em 10 amostras caninas (14,28%) e quatrofelinas (36,36%). Nas amostras caninas, ovos de ancilostomídeos foram os mais encontrados em 43 (61,43%) amostras,enquanto os coccídeos foram mais freqüentemente observados nas fezes de felinos em três (27,27%) amostras. Quanto àidade dos animais, 37 (52,85%) amostras positivas eram provenientes de animais com mais de 1 ano de idade, indicandoprovável vermifugação dos filhotes, enquanto nos gatos a faixa etária mais parasitada foi de menos de seis meses, com 7(63,63%) positivos.

Combined off-pump myocardial revascularization and carotid endarterectomy: early experience.

BACKGROUND: Controversy remains regarding the optimal surgical management of patients with coexisting significant carotid and coronary artery disease. The debate has deepened by the evolution of new approaches for the treatment of both coronary and carotid disease. We report our early experience with combined off-pump coronary artery bypass (OPCAB) and carotid endarterectomy (CEA) for the treatment of patients with coexisting coronary and carotid disease. METHODS: Our computer database was examined to obtain patients and their demographics and clinical profiles. Operative reports were reviewed. Telephone interviews were conducted to assess follow-up status. RESULTS: Thirteen patients underwent combined OPCAB and CEA. Average age was 71 years. The CEA was performed with intraluminal shunting and patch reconstruction. On average, 3.6 bypass grafts were performed. There were no gross neurologic complications or myocardial infarctions. Excluding an outlier, mean length of hospital stay was 8.2 days. All patients were well on follow-up (2 weeks to 16 months). CONCLUSIONS: A combined OPCAB and CEA strategy appears safe and effective. Further follow-up and experience is warranted before conclusions regarding potential benefits of this approach for staged or conventional OPCAB/CEA procedures can be made.

Does low-dose aspirin therapy complicate oral surgical procedures?

BACKGROUND: The fear of uncontrolled bleeding often prompts medical practitioners to stop aspirin intake for seven to 10 days before any surgical procedure. The authors initiated this study to evaluate the effect of aspirin on bleeding in patients undergoing oral surgery. METHODS: The study group consisted of 39 patients who were scheduled to undergo dental extractions. All patients were receiving 100 milligrams of aspirin daily on a regular basis. The authors randomly divided the patients into two groups: those who stopped the aspirin therapy before the procedure and those who continued the aspirin therapy. One hour before the procedures, all patients underwent a bleeding time test. In addition, the amount of bleeding during the procedure was measured. RESULTS: The mean (+/- standard deviation) bleeding time was 1.8 +/- 0.47 minutes for patients who stopped aspirin therapy one week before the procedure. For patients who continued aspirin therapy, the bleeding time was 3.1 +/- 0.65 minutes. The difference was statistically significant (P = .004). However, both groups were within the normal bleeding time range, and in both groups, a local hemostatic method was sufficient to control bleeding. No episodes of uncontrolled intraoperative or postoperative bleeding were noted. CONCLUSION: Low-dose aspirin therapy should not be stopped before oral surgery. Local hemostasis is sufficient to control bleeding. CLINICAL IMPLICATIONS: Patients receiving aspirin therapy to prevent blood clot formation may be subject to emboli formation if the treatment is stopped. The results of this study show that aspirin therapy should be continued throughout oral surgical procedures. Local measures are sufficient to control any bleeding during surgery.

Chondrosarcoma of the aorta: a rare source of bowel and lower extremity emboli.

Malignant aortic tumors occur infrequently. At least 70 cases of primary aortic malignancies have been reported in the literature. Within this group, chondrosarcoma is exceedingly rare, with only 1 case having been reported. An aortic chondrosarcoma developed in our patient and embolized to the small bowel and lower extremities. Although initially thought to arise from the abdominal aorta, this tumor, in fact, originated from the thoracic aorta. This case illustrates the need for complete aortic imaging when unexplained recurrent embolization occurs. In general, the survival rates with chondrosarcoma are diminished, but this patient survived 69 months after he was initially seen.

Abdominal aortic aneurysm in a young child: a 25-year follow-up study.

Although abdominal aortic aneurysm (AAA) is a common problem in elderly patients, AAA is rare in children. Despite its rarity, early diagnosis is imperative to prevent limb-threatening or fatal complications. The treatment may be complicated, because it must allow for the growth of the child. A saccular AAA in an 11-year-old boy, complicated by three repeated embolizations to the lower extremities and treated by aneurysmorrhaphy 25 years ago, was studied. In addition, the long-term function of a vein interposition graft in the common femoral artery was identified.

Endothelial cell adaptation to chronic thrombosis.

BACKGROUND: The autogenous vein graft has proven to be the most durable conduit in lower extremity vascular bypass grafts. Failures due to thrombosis, intimal hyperplasia, and progression of atherosclerotic disease commonly plague the vascular surgeon. Part of the ability of vein grafts to provide a nonthrombogenic surface relies on the capability of the endothelial cell to produce prostacyclin, a potent vasodilator and inhibitor of platelet aggregation. Once a graft fails and thromboses, little is known as to the effects of the thrombus on the function and morphology of endothelial cells. Earlier studies by this laboratory demonstrated the ability of arterialized canine vein grafts to recover function after 5 days of exposure to thrombus. This investigation sought to explore the limits of endothelial cell viability and recovery to extended periods of thrombosis. METHODS: Using a canine model of arterialized vein grafts, prostacyclin production (measured as 6-keto-PGF1a) was assessed in an ex vivo perfusion system from grafts exposed to thrombus for 10 days (group I) and 20 days (group II). Both groups underwent thrombectomy and a recovery period of 30 days. The grafts were perfused with Hanks' balanced salt solution and samples were obtained at 5 and 30 minutes to determine prostacyclin levels. Arachidonic acid was then added to a new perfusate of Hanks' solution and samples were again obtained at 5 and 30 minutes. Results were expressed as PGF/graft area (cm2/min). Representative samples of each graft underwent scanning electron microscopy. RESULTS: Without arachidonic acid, prostacyclin production of group II (20 day) grafts was greater than group I (10 day) grafts at 5 minutes of perfusion (4.31 versus 2.42, P = 0.08) and at 30 minutes (1.86 versus 0.95, P = 0.02). In response to the addition of arachidonic acid both groups increased prostacyclin production (group I, P = 0.004; group II, P = 0.12). A comparison was made between prostacyclin production at baseline and after addition of arachidonic acid. Group I grafts demonstrated a greater percent increase in prostacyclin production compared to group II (385% versus 229%, P = 0.01). Scanning electron microscopy showed no differences in endothelial coverage between the study groups. CONCLUSIONS: These results demonstrate that although endothelial cells are able to recover a basal level of prostacyclin production, the response to substrate stimulation diminishes with increased exposure time to thrombus. This diminished response may be important in understanding the ability of vein grafts to survive after a period of thrombosis.

Ultrasound-guided pseudoaneurysm compression: efficacy after coronary stenting and angioplasty.

PURPOSE: Ultrasound-guided compression of femoral pseudoaneurysms has often obviated the need for open operative repair. Increasing use of percutaneous interventional cardiac procedures has created pseudoaneurysms with a large-caliber arterial defect, often in patients who are placed immediately on anticoagulation therapy. This report describes the prospectively collected information from our vascular laboratory regarding ultrasound-guided compression of these pseudoaneurysms after cardiac procedures, both interventional and diagnostic. METHODS: Since March 1994 prospective data collection for patients who have undergone pseudoaneurysm compression in our vascular laboratory has recorded information including cardiac procedure, size of catheter or sheath, coagulation parameters, pseudoaneurysm size and location, and time to compression. Forty-one patients underwent attempted ultrasound-guided pseudoaneurysm compression after cardiac procedures: 19 after cardiac catheterization alone, seven after angioplasty, one after atherectomy, two after insertion and subsequent removal of an intraaortic balloon pump, and 12 after coronary stenting. RESULTS: Compression was successful overall in 88% of the patients (36 of 41). Successful compression of the pseudoaneurysm was seen in 95% after catheterization alone, 100% after angioplasty, 100% after atherectomy, and 100% after intraaortic balloon pumping, as compared with 67% after stenting (eight of 12 vs 28 of 29; p = 0.02). A sheath size of 9F or greater was a significant factor in predicting unsuccessful compression (three of eight vs two of 33; p = 0.04). Abnormal coagulation parameters were present in 20 of the 41 patients and was not significantly different in patients who were successfully or unsuccessfully treated (four of five vs 16 of 36; p = 0.40). CONCLUSIONS: Pseudoaneurysms after cardiac procedures and interventions can often be successfully compressed with an ultrasound-guided technique. The presence of abnormal coagulation parameters was not identified as a risk factor for compression failure and should not dissuade attempted compression. Stent placement was more likely to result in unsuccessful compression, and this appeared to be a result of the larger size of the arterial defect. Even in this setting, compression achieved obliteration of the pseudoaneurysm in more than half of the patients.

The effect of thrombus on the vascular endothelium of arterialized vein grafts.

BACKGROUND: It is known that vein grafts can be salvaged by clot removal, but patency rates are diminished. This study was designed to determine the effects of thrombus on vascular endothelium and the ability of the endothelium to recover normal function. METHODS: Thirty external jugular vein grafts were placed as bilateral femoral artery interposition grafts in 15 mongrel dogs and allowed to arterialize for a period of at least 12 weeks. Six control grafts were not exposed to thrombus (C-NT). Six other control grafts were exposed to thrombus for 7 days and removed, ie, allowed no in vivo recovery (C-T). The remaining 18 grafts in 9 canines were exposed to autologous thrombus for 5 days and then flow was restored. The right femoral graft was removed 7 days after thrombectomy and the left removed 30 days after thrombectomy. At the time of removal, the grafts were perfused with a balanced salt solution alone and then with arachidonic acid added to the same volume of the salt solution. Perfusates were collected at 5, 15, and 30 minutes. These perfusates were assayed for the presence of 6-keto-prosglandin F1 alpha (6-keto-PGF1(1 alpha)), a metabolite of prostacyclin (PGI2). Over the 30-day recovery period, the amounts of 6-keto-PGF1(1 alpha) produced with and without arachidonic acid added were compared to assess endothelial response. Electron micrographs of the endothelium of all vein grafts were compared to the assay findings. RESULTS: When arachidonic acid was added to the perfusion system, there was a several fold increase in the production of 6-keto-PGF1(1 alpha) over baseline in all grafts allowed recovery. Grafts (C-T) that were allowed no in vivo recovery had no response to arachidonic acid. Ratios of 6-keto-PGF1(1 alpha) production with arachidonic acid stimulation to 6-keto-PGF1(1 alpha) production without stimulation were calculated to compare endothelial function. The electron micrographs showed the vascular endothelium to be severely injured after contact with thrombus, but recovered by 7 days. CONCLUSIONS: This study suggests that the endothelium of canine vein grafts is injured by contact with thrombus for 5 days but can recover structure and function. This recovery is detectable at 7 days post-thrombectomy.

Guidelines for carotid endarterectomy. A multidisciplinary consensus statement from the Ad Hoc Committee, American Heart Association.

BACKGROUND AND PURPOSE: Indications for carotid endarterectomy have engendered considerable debate among experts and have resulted in publication of retrospective reviews, natural history studies, audits of community practice, position papers, expert opinion statements, and finally prospective randomized trials. The American Heart Association assembled a group of experts in a multidisciplinary consensus conference to develop this statement. METHODS: A conference was held July 16-18, 1993, in Park City, Utah, that included recognized experts in neurology, neurosurgery, vascular surgery, and healthcare planning. A program of critical topics was developed, and each expert presented a talk and provided the chairman with a summary statement. From these summary statements a document was developed and edited onsite to achieve consensus before final revision. RESULTS: The first section of this document reviews the natural history, methods of patient evaluation, options for medical management, results of surgical management, data from position statements, and results to date of prospective randomized trials for symptomatic and asymptomatic patients with carotid artery disease. The second section divides 96 potential indications for carotid endarterectomy, based on surgical risk, into four categories: (1) Proven: This is the strongest indication for carotid endarterectomy; data are supported by results of prospective contemporary randomized trials. (2) Acceptable but not proven: a good indication for operation; supported by promising but not scientifically certain data. (3) Uncertain: Data are insufficient to define the risk/benefit ratio. (4) Proven inappropriate: Current data are adequate to show that the risk of surgery outweighs any benefit. CONCLUSIONS: Indications for carotid endarterectomy in symptomatic good-risk patients with a surgeon whose surgical morbidity and mortality rate is less than 6% are as follows. (1) Proven: one or more TIAs in the past 6 months and carotid stenosis > or = 70% or mild stroke within 6 months and a carotid stenosis > or = 70%; (2) acceptable but not proven: TIAs within the past 6 months and a stenosis 50% to 69%, progressive stroke and a stenosis > or = 70%, mild or moderate stroke in the past 6 months and a stenosis 50% to 69%, or carotid endarterectomy ipsilateral to TIAs and a stenosis > or = 70% combined with required coronary artery bypass grafting; (3) uncertain: TIAs with a stenosis < 50%, mild stroke and stenosis < 50%, TIAs with a stenosis < 70% combined with coronary artery bypass grafting, or symptomatic, acute carotid thrombosis; (4) proven inappropriate: moderate stroke with stenosis < 50%, not on aspirin; single TIA, < 50% stenosis, not on aspirin; high-risk patient with multiple TIAs, not on aspirin, stenosis < 50%; high-risk patient, mild or moderate stroke, stenosis < 50%, not on aspirin; global ischemic symptoms with stenosis < 50%; acute dissection, asymptomatic on heparin. Indications for carotid endarterectomy in asymptomatic good-risk patients performed by a surgeon whose surgical morbidity and mortality rate is less than 3% are as follows. (1) Proven: none. As this statement went to press, the National Institute of Neurological Disorders and Stroke issued a clinical advisory stating that the Institute has halted the Asymptomatic Carotid Atherosclerosis Study (ACAS) because of a clear benefit in favor of surgery for patients with carotid stenosis > or = 60% as measured by diameter reduction. When the ACAS report is published, this indication will be recategorized as proven. (2) acceptable but not proven: stenosis > 75% by linear diameter; (3) uncertain: stenosis > 75% in a high-risk patient/surgeon (surgical morbidity and mortality rate > 3%), combined carotid/coronary operations, or ulcerative lesions without hemodynamically significant stenosis; (4) proven inappropriate: operations with a combined stroke morbidity and mortality > 5%.

Guidelines for carotid endarterectomy. A multidisciplinary consensus statement from the ad hoc Committee, American Heart Association.

BACKGROUND AND PURPOSE: Indications for carotid endarterectomy have engendered considerable debate among experts and have resulted in publication of retrospective reviews, natural history studies, audits of community practice, position papers, expert opinion statements, and finally prospective randomized trials. The American Heart Association assembled a group of experts in a multidisciplinary consensus conference to develop this statement. METHODS: A conference was held July 16-18, 1993, in Park City, Utah, that included recognized experts in neurology, neurosurgery, vascular surgery, and healthcare planning. A program of critical topics was developed, and each expert presented a talk and provided the chairman with a summary statement. From these summary statements a document was developed and edited onsite to achieve consensus before final revision. RESULTS: The first section of this document reviews the natural history, methods of patient evaluation, options for medical management, results of surgical management, data from position statements, and results to date of prospective randomized trials for symptomatic and asymptomatic patients with carotid artery disease. The second section divides 96 potential indications for carotid endarterectomy, based on surgical risk, into four categories: (1) Proven: This is the strongest indication for carotid endarterectomy; data are supported by results of prospective contemporary randomized trials. (2) Acceptable but not proven: a good indication for operation; supported by promising but not scientifically certain data. (3) Uncertain: Data are insufficient to define the risk/benefit ratio. (4) Proven inappropriate: Current data are adequate to show that the risk of surgery outweighs any benefit. CONCLUSIONS: Indications for carotid endarterectomy in symptomatic good-risk patients with a surgeon whose surgical morbidity and mortality rate is less than 6% are as follows. (1) Proven: one or more TIAs in the past 6 months and carotid stenosis > or = 70% or mild stroke within 6 months and a carotid stenosis > or = 70%; (2) acceptable but not proven: TIAs within the past 6 months and a stenosis 50% to 69%, progressive stroke and a stenosis > or = 70%, mild or moderate stroke in the past 6 months and a stenosis 50% to 69%, or carotid endarterectomy ipsilateral to TIAs and a stenosis > or = 70% combined with required coronary artery bypass grafting; (3) uncertain: TIAs with a stenosis < 50%, mild stroke and stenosis < 50%, TIAs with a stenosis < 70% combined with coronary artery bypass grafting, or symptomatic, acute carotid thrombosis; (4) proven inappropriate: moderate stroke with stenosis < 50%, not on aspirin; single TIA, < 50% stenosis, not on aspirin; high-risk patient with multiple TIAs, not on aspirin, stenosis < 50%; high-risk patient, mild or moderate stroke, stenosis < 50%, not on aspirin; global ischemic symptoms with stenosis < 50%; acute dissection, asymptomatic on heparin. Indications for carotid endarterectomy in asymptomatic good-risk patients performed by a surgeon whose surgical morbidity and mortality rate is less than 3% are as follows. (1) Proven: none. (As this statement went to press, the National Institute of Neurological Disorders and Stroke issued a clinical advisory stating that the Institute has halted the Asymptomatic Carotid Atherosclerosis Study (ACAS) because of a clear benefit in favor of surgery for patients with carotid stenosis > or = 60% as measured by diameter reduction. When the ACAS report is published, this indication will be recategorized as proven. (2) acceptable but not proven: stenosis > 75% by linear diameter; (3) uncertain; stenosis > 75% in a high-risk patient/surgeon (surgical morbidity and mortality rate > 3%), combined carotid/coronary operations, or ulcerative lesions without hemodynamically significant stenosis; (4) proven inappropriate: operations with a combined stroke morbidity and mortality > 5%.

Forward-looking intravascular ultrasonography: in vitro imaging of normal and atherosclerotic human arteries.

Inadequate guidance of angioplasty devices limits the endoluminal treatment of high grade atherosclerotic stenoses and total occlusions. Conventional intraluminal ultrasound systems (IVUS) enable lateral cross-sectional imaging of tomographic sections of the vessel wall, but do not offer imaging in front of the catheter. This study describes our initial experience with a forward-looking intravascular ultrasound (FL-IVUS) system (Echoeye, EchoCath, Inc., Princeton, NJ). The acoustic beam from a 25.5 MHz piezoelectric transducer on a 7.5 Fr catheter is mechanically rotated in a forward-looking spiral fashion at 300 cycles/second. Sixty-four axially aligned, cross-sectional, real time images are obtained from a truncated, 60 degree conical volume located 5 to 10 mm from the catheter tip. Luminal dimensions (n = 51) of human cadaveric femoral arteries (cast in agar and submerged in saline) measured by the FL-IVUS were compared to histologic cross-sections of the vessel with a correlation of r = 0.92. FL-IVUS accurately imaged the narrowing lumen in front of total occlusions and the geometry at vessel branches, and identified the location of lesions and the shape and morphology of vessel wall thickness. The 7.5 Fr FL-IVUS over-estimated luminal dimensions in vessels larger than 5 mm. We conclude that FL-IVUS imaging shows promise as a new, accurate method for identifying and characterizing high grade atherosclerotic stenoses and total occlusions, and expands the current capabilities of conventional IVUS systems.

Stenting of proximal venous obstructions to maintain hemodialysis access.

PURPOSE: The purpose of the study was to evaluate the efficacy of stenting central venous obstructions in patients dependent on hemodialysis to preserve or restore central venous patency and allow for continued hemodialysis from the affected side. METHODS: Twenty-five self-expanding (17) and balloon-expandable (8) stainless steel stents were deployed in 19 patients with end-stage renal disease and central venous stenosis or occlusion. Nineteen lesions were treated: 11 subclavian and eight innominate. Twenty-two stents were initially implanted. RESULTS: Stent deployment was successful in all cases and immediately remedied the underlying cause of venous hypertension. Follow-up at up to 17 months revealed three deaths from unrelated causes, one occlusion at 3.25 months, and three restenoses at 16 days, 2.5 and 5 months, respectively, with successful implantation of three additional stents for a primary central patency rate of 68% (+/- 14%) and secondary central patency rate of 93% (+/- 7%). CONCLUSIONS: Stenting of subclavian and innominate venous stenoses and occlusions effectively corrected the underlying lesions responsible for disturbed hemodynamics and, in most cases, prolonged available hemodialysis access from the affected side. Stents seem to be valuable adjuncts in the management of failing hemodialysis access due to central venous stenosis or occlusion.

Transcutaneous ultrasonography can be used to guide and monitor balloon angioplasty.

PURPOSE: Percutaneous balloon angioplasty is an accepted technique for the treatment of short segmental stenoses of the iliac and superficial femoral arteries. Some surgeons have not embraced this technique because of lack of training, unfamiliarity with radiologic equipment, or poor-quality fluoroscopy equipment in the operating room. A new technique, ultrasound-directed balloon angioplasty, enables the vascular surgeon to guide the catheter and evaluate the progress of the procedure without the use of radiographic imaging. METHODS: The new catheter is integrated externally into a standard duplex scanner. A spherical brass bead positioned on the catheter shaft in the middle of the balloon is covered with a piezoelectric material. This omnidirectional receiver is connected through a wire to a catheter interface system, which allows the exact position of the balloon to be represented on the screen of a duplex unit. The catheter is advanced under visual control with use of the scanner. RESULTS: The system has been used to perform balloon angioplasty on 21 lesions (16 superficial femoral, 3 iliac, 2 popliteal arteries) in 17 patients. Procedures in 16 patients were performed percutaneously; in an additional patient bilateral angioplasties were performed during operation. The balloon was successfully positioned in each case with use of ultrasonography alone; each procedure was confirmed by use of angiography. Angioplasty was accomplished in 16 (76%) of 21 with the ultrasound-guided catheter alone. Supplemental use of a high-pressure balloon or atherectomy device was necessary in five patients. CONCLUSIONS: This technique records physiologic and anatomic data in real time so that the progress of the angioplasty can be monitored. In three patients the inadequacy of the initial angioplasty was recognized by a persistent velocity increase but not by angiography. As a result corrective measures were taken. This new procedure allows vascular surgeons to use equipment with which they are familiar, reduces the risk of ionizing radiation and contrast nephropathy, and permits the monitoring of the angioplasty with hemodynamic parameters.

Ultrasound Guided Balloon Angioplasty: What is its Role?

A modified angioplasty catheter has been developed which can be guided-into position with duplex ultrasound. This reduces the risks of ionizing radiation and contrast agents and uses a modality familiar to the vascular surgeon. This catheter was tested successfully in a canine model for safety, accuracy and therapeutic efficacy. Following FDA approval, clinical trials in humans were initiated. This paper describes the preliminary results with use of this device in humans.

Ultrasound-guided balloon angioplasty is a new technique for vascular surgeons.

A new catheter has been developed that can be accurately and precisely positioned using duplex ultrasonography alone. A piezoelectric transducer that functions as a passive, omnidirectional receiver is attached to the mid-balloon region of an angioplasty catheter. Integration to a standard duplex imaging system allows visualization of this receiver in all planes, with the location of the receiver represented by a flashing bright arrow superimposed on the ultrasound B-mode image. This catheter was tested successfully in 10 dogs with bilateral femoral arteriovenous fistulas. With the use of duplex guidance, eight arterial and three venous stenoses were dilated and two stents were placed. Catheter placements and therapeutic outcomes predicted by ultrasound correlated with arteriographic findings. Ultrasound guidance has several advantages. It eliminates the risks associated with radiographic imaging. It also reduces patient costs and discomfort. Furthermore, procedures can be monitored continuously in real time with the collection of anatomic and physiologic data.