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PubMed1989

Angioplasty and stenting of completely occluded iliac arteries.

Percutaneous angioplasty and placement of balloon-expandable intraluminal stents were performed in 12 iliac occlusions in 12 patients. Indications were limb salvage in seven and claudication in five. After successful stenting, ankle-brachial indexes improved by 0.15 or more in 11 of 12 patients (mean increase, 0.40), transstenotic pressure gradients decreased to less than 5 mm Hg (mean, 0.58 mm Hg) in all patients, and improvement in clinical grade was seen in all patients. At follow-up at 1-14 months (median, 6 months), ankle-brachial indexes were stable (mean, 0.95), and clinical grades were unchanged in all patients. Complications occurred in two patients; both experienced distal embolization, and one, who was receiving corticosteroid therapy, also suffered stent thrombosis. Local surgical embolectomy was successful in both patients, and the thrombosed stent was recanalized with urokinase. This early experience suggests that stenting may play an important role in the management of iliac occlusions, especially in poor surgical candidates.

Adult↗
PubMed1988

Acute pulmonary embolism: diagnostic value of digital subtraction angiography.

Digital subtraction angiography (DSA) performed via a peripheral vein was compared prospectively with selective conventional pulmonary angiography (CPA) in 54 patients suspected of having pulmonary embolism (PE). All patients also underwent ascending venography. In contrast to the conventional pulmonary angiograms, all of which were considered satisfactory, 13 of 54 digital subtraction angiograms (24%) were technically unsatisfactory. The interpretable digital subtraction angiograms had 81% sensitivity and 64% specificity. With DSA, one cannot exclude the diagnosis of PE on the basis of normal angiograms (27% false-positive results) as one can with perfusion scanning. On the other hand, DSA showed good sensitivity (94%) in medium to major PE. Therefore it may be the technique of choice in the screening of life-threatening PE for which curative emergency treatment with thrombolytic agents or embolectomy is often necessary.

Acute Disease↗
PubMed1990

Fibrinolytic therapy for upper-extremity arterial occlusions.

Acute upper-extremity arterial occlusion may be due to embolic phenomena or de novo thrombosis. If the occlusion is left untreated, claudication or ischemia necessitating amputation can occur. Operative Fogarty-balloon embolectomy has been the treatment of choice for this entity. In a 6-year period the authors used fibrinolysis on nine occasions in eight patients to treat acute upper-extremity arterial occlusions. Concomitant balloon angioplasty was helpful in four cases. Success, defined as a normal hand with at least one artery that was continuously patent to the wrist, was achieved in all patients. A single significant groin hematoma was seen. Neither stroke nor death occurred in any case, and no amputations were necessary. Local transcatheter intraarterial administration of urokinase can be considered a first-line treatment for brachial artery embolus and other causes of acute upper-extremity arterial occlusion.

Adult↗
PubMed1991

Clot-trapper device for transjugular thrombectomy from the inferior vena cava.

The clot-trapper device for transjugular thrombectomy was used in 10 dogs with acute thrombosis and two dogs with chronic thrombosis. In eight of these animals, the clots were trapped with the clot-trapper device, then a mechanical thrombectomy device was used to destroy the clots. In 10 animals, including eight with in vitro thrombi and two with in situ thrombi, thrombi were efficiently trapped with the clot-trapper device. In two animals, pulmonary embolism occurred because of a discrepancy between the diameter of the inferior vena cava and the diameter of the bag opening. After increasing the size of the loop to match the diameter of the inferior vena cava, trapping of all thrombi was possible in both experiments (acute and chronic thrombosis). The clot-trapper device, in conjunction with an embolectomy balloon catheter and/or a mechanical thrombectomy device, facilitates the removal of thrombi from the inferior vena cava and iliac veins.

Animals↗
PubMed1995

Thrombolysis of lower extremity embolic occlusions: a study of the results of the STAR Registry.

PURPOSE: To evaluate thrombolysis as primary therapy for lower extremity embolic occlusions. MATERIALS AND METHODS: Forty-five of 306 consecutive cases of lower extremity arterial occlusions treated with urokinase and registered in the Society of Cardiovascular and Interventional Radiology Transluminal Angioplasty and Revascularization Registry were believed on the basis of clinical and angiographic findings to be due to emboli. RESULTS: Comorbidity included atrial fibrillation in 50%, previous myocardial infarction in 40%, and a cerebrovascular event in 35%. Thirty-two (71%) limbs were viable, 12 (27%) were threatened, and one had irreversible ischemia. Mean symptom duration was 8.6 days. Average occlusion length was 17 cm. The distribution of emboli was 4% aortoiliac, 65% femoropopliteal, 24% tibial, and 7% graft. Major complications occurred in eight of 45 patients (18%). The technical success rate was 69%, with a 1- and 2-year primary patency of 79% for initially successful intraarterial thrombolyses. CONCLUSION: Thrombolysis of embolic occlusions is successful in most cases. Limb salvage and survival rates are similar to historical reports for surgical embolectomy.

Adult↗
PubMed1997

Superior mesenteric arterial embolism: local fibrinolytic treatment with urokinase.

PURPOSE: To evaluate the efficacy of intraarterial urokinase in the treatment of superior mesenteric arterial (SMA) embolism. MATERIALS AND METHODS: Within 3 years, 10 patients (six men, four women; aged 62-82 years) with angiographically proved SMA emboli were selected on the basis of absence of peritoneal signs of intestinal necrosis at physical examination and normal abdominal plain radiographs to undergo local lysis with urokinase. RESULTS: The procedure was performed without complications in all 10 patients. The embolus was successfully lysed in nine patients (90%). Clinical success was achieved in seven patients (70%); however, in one patient laparotomy was required to confirm the clinical finding. None of these patients had recurrent embolism or postischemic intestinal stenosis during follow-up (mean, 11.2 months). The three remaining patients (30%) underwent laparotomy subsequent to failure of intraarterial treatment with urokinase. CONCLUSION: Fibrinolytic treatment with urokinase may be an effective alternative to surgical embolectomy in patients with SMA embolism without clinical or radiologic signs of intestinal infarction. In this small series, abatement of abdominal pain in the 1st hour of fibrinolytic treatment was the best indicator of clinical success. Pain persisted in patients with intestinal infarction.

Aged↗
PubMed1999

In vitro effectiveness study of three hydrodynamic thrombectomy devices.

PURPOSE: To determine the in vitro efficacy of three hydrodynamic thrombectomy devices. MATERIALS AND METHODS: Thrombectomy of clots was performed with three thrombectomy devices (Angiojet [AJ], Possis Medical, Minneapolis, Minn; Hydrolyser [HL] Cordis Europe, Roden, the Netherlands; and the Shredding Embolectomy Thrombectomy [SET] catheter, HP-Medica, Augsburg, Germany) in a flow model. RESULTS: Mean thrombectomy time ranged from 10.22 seconds (HL) to 37.73 seconds (AJ with guide wire). For the AJ and HL, the use of guide wires prolonged thrombectomy time (P < .01). The AJ with and without a guide wire and the HL with a 0.018-inch guide wire worked isovolumetrically, whereas the mean ratio of applied saline and aspirated fluid for the other devices was different from 1, ranging from 0.54 to 0.72. Mean embolus weight with the AJ alone (56.44 mg) was significantly higher than that with the SET catheter alone (3.15 mg) and with a guide wire (1.31 mg, P < .01 for both) and the HL alone (3.9 mg, P < .05), as was the embolus weight with the HL with a 0.018-inch guide wire (66.5 mg) compared with the SET catheter with and without a guide wire (P < .01), AJ with a guide wire (22.33 mg, P < .05), the HL alone (P < .01), and the HL with a 0.025-inch guide wire (24.86 mg, P < .05). CONCLUSION: The devices showed performance differences. The SET catheter alone and with a guide wire and the HL may bear an increased risk of procedure-related anemia. In clinical applications, hydrodynamic thrombectomy might substantially reduce the need for thrombolytic therapy.

Equipment Design↗
PubMed2004

Perivascular gene transfer of NADPH oxidase inhibitor suppresses angioplasty-induced neointimal proliferation of rat carotid artery.

Vascular stretch induces NADPH oxidase-derived superoxide anion (O2-), which has been implicated in hypertrophy and cell proliferation. We hypothesized that targeted delivery of an NADPH oxidase inhibitor to the adventitia would reduce stretch-induced vascular O2- and attenuate neointima formation. We designed a novel replication-deficient adenovirus containing a fibroblast-active promoter driving expression of NADPH oxidase inhibitory sequence gp91ds (Ad-PDGFbetaR-gp91ds/eGFP). 1) We characterized the specificity of this promoter using pPDGFbetaR-luciferase by showing induction of luciferase in cultured rat aortic fibroblasts but not in vascular smooth muscle cells. 2) Using RT-PCR, we observed expression of gp91ds and the reporter gene in fibroblasts after infection with Ad-PDGFbetaR-gp91ds/eGFP. 3) Using Ad-CMV-eGFP as a control, we delivered Ad-PDGFbetaR-gp91ds/eGFP to the adventitia of the rat common carotid artery (CCA). Immunohistochemistry confirmed localized delivery of the inhibitor to the adventitia. After CCAs were injured with an embolectomy catheter, we observed a significant increase in neointima-to-media area ratio in control CCAs, which was significantly attenuated in CCAs treated with the gp91ds-expressing virus. In a second group of rats, we detected a 10-fold increase in distension-stimulated O2-, which was significantly reduced in CCAs infected with gp91ds-expressing virus. These data demonstrate that localized adventitial delivery of an NADPH oxidase inhibitor is effective in reducing overall vascular O2- and neointima formation, suggesting that adventitial NADPH oxidase plays a functional role in development of neointimal hyperplasia.

Angioplasty, Balloon↗
PubMed1994

Increased SMC proliferation after endothelial injury in hyperinsulinemic obese Zucker rats.

The long-term effect of long-lasting hyperinsulinemia on aortic smooth muscle cell (SMC) proliferation after endothelial injury was investigated using the obese Zucker rat model, which is characterized especially by early spontaneous development of hyperinsulinemia and insulin resistance. SMC proliferation was provoked by the passage of an embolectomy catheter with a tightly inflated balloon and was assessed by measuring the incorporation of [3H]thymidine in the DNA of intima-media layers. Compared with controls, the SMC mitotic activity was not significantly increased from day 2 to day 7 after injury, but from day 14 to day 30 after endothelial denudation, SMC proliferation was significantly less decreased in obese than in lean rats [on day 14, DNA synthesis = 107 +/- 18 counts.min-1.micrograms DNA-1 in lean and 345 +/- 44 counts.min-1.micrograms DNA-1 in obese rats (P = 0.003); and on day 30, DNA synthesis = 74 +/- 18 counts.min-1.micrograms DNA-1 in lean and 133 +/- 19 counts.min-1.micrograms DNA-1 in obese rats (P = 0.0055)]. As a result, the intima-media DNA content was higher in obese than in lean rats on day 14 and even more so on day 30, suggesting a higher amount of SMCs in the intima-media. Moreover, on day 30, the aortic thickening, as measured by a histomorphometric technique, was much higher in obese than in lean rats. This difference was entirely due to an increase in SMC content of the intima, mainly resulting from a dramatic increment in the number of nuclei and nuclear number density.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1999

Responses of simultaneously recorded respiratory-related medullary neurons to stimulation of multiple sensory modalities.

This study addresses the hypothesis that multiple afferent systems share elements of a distributed brain stem network that modulates the respiratory motor pattern. Data were collected from 18 decerebrate, bilaterally vagotomized, paralyzed, artificially ventilated cats. Up to 28 neurons distributed in the rostral and caudal ventral respiratory group, nucleus tractus solitarius, and raphe obscurus were recorded simultaneously with microelectrode arrays. Phases of the respiratory cycle and inspiratory drive were assessed from integrated efferent phrenic nerve activity. Carotid chemoreceptors were stimulated by injection of CO2-saturated saline solution via the external carotid artery. Baroreceptors were stimulated by increased blood pressure secondary to inflation of an embolectomy catheter in the descending aorta. Cutaneous nociceptors were stimulated by pinching a footpad. Four hundred seventy-four neurons were tested for respiratory modulated firing rates and responses; 403 neurons were tested with stimulation of all 3 modalities. Chemoreceptor stimulation and pinch, perturbations that tend to increase respiratory drive, caused similar responses in 52 neurons; 28 responded oppositely. Chemoreceptor and baroreceptor stimulation resulted in similar primary responses in 45 neurons; 48 responded oppositely. Similar responses to baroreceptor stimulation and pinch were recorded for 38 neurons; opposite effects were measured in 26 neurons. Among simultaneously recorded neurons, distinct combinations of firing rate changes were evoked in response to stimulation of the different modalities. The results show a functional convergence of information from carotid chemoreceptors, baroreceptors, and cutaneous nociceptors on respiratory-modulated neurons distributed in the medulla. The data are consistent with the hypothesis that brain stem neurons have overlapping memberships in multifunctional groups that influence the respiratory motor pattern.

Animals↗
PubMed1998

New perspectives for treatment of pulmonary embolism.

Subcutaneous low-molecular-weight heparins (LMWHs) have been shown to be as safe and effective as intravenous unfractionated heparin (UFH) for the initial treatment of patients with deep vein thrombosis and acute symptomatic pulmonary embolism. In comparison with UFH, LMWHs have a longer half-life, greater bioavailability and more predictable antithrombotic effect when administered in fixed doses, thus obviating the need for laboratory monitoring. It is therefore feasible that LMWH preparations may replace UFH for the treatment of pulmonary embolism in the future. It is recommended that LMWH should be administered for 5-10 days and should overlap with oral anticoagulant therapy by at least 4 days. Surgical pulmonary embolectomy should only be considered in patients with life-threatening pulmonary embolism who have failed to respond during the first 3 h of thrombolytic therapy. The systematic use of vena cava filters is not recommended in patients presumed to be at high risk for pulmonary embolism.

Anticoagulants↗
PubMed2000

Successful interventional treatment of renal insufficiency caused by renal artery pseudoaneurysm with concomitant arteriovenous fistula.

Asymptomatic arteriovenous fistulae and pseudoaneurysms are common after renal biopsy. We present a patient with a single kidney and symptomatic pseudoaneurysm of the renal artery with concomitant arteriovenous fistula as a rare complication following surgical embolectomy. The patient developed renal insufficiency because of a significant degree of vascular steal caused by the fistula. Dialysis was performed for more than 6 months until the fistula was diagnosed. The fistula and the pseudoaneurysm were successfully treated by superselective arterial embolization with metallic coils. Renal function improved within the next 2 weeks and no further dialysis was necessary.

Aneurysm, False↗
PubMed2004

Inward remodeling of the rabbit aorta is blocked by the matrix metalloproteinase inhibitor doxycycline.

Constrictive arterial remodeling accounts for a significant proportion of lumen loss in atherosclerotic progression and postangioplasty stenosis. Recent research suggests that constrictive remodeling is mediated by turnover of the extracellular matrix. We hypothesized that remodeling could be attenuated by treatment with the safe, effective matrix metalloproteinase (MMP) inhibitor doxycycline. Female rabbit abdominal aortas were denuded using a 4-Fr balloon embolectomy catheter, and reinjured 3 weeks later. Treatment with 30 mg/kg/day doxycycline was begun the day before the second injury. At 6 weeks after injury, lumen area measured 13.1 +/- 1.2 mm(2) in controls compared to 17.5 +/- 1.6 mm(2) in doxycycline-treated rabbits (p = 0.05). At 4 days after injury, MMP-2 activity was increased compared to uninjured controls, but doxycycline treatment reduced MMP-2 activity. Doxycycline treatment also inhibited fibrillar collagen deposition in the intima by 87% as detected by polarized light microscopy. Doxycycline was an effective inhibitor of constrictive arterial remodeling in the rabbit aorta. Treatment reduced MMP activity and attenuated the deposition of extracellular matrix particularly in the intima.

Angioplasty, Balloon↗
PubMed1989

Changing electrocardiographic findings in pulmonary embolism in relation to vascular obstruction.

Electrocardiographic (ECG) findings in 87 consecutive patients with from minor to massive pulmonary embolism are presented. ECG changes suggestive of acute right ventricular strain defined as the occurrence of complete (c) or incomplete (inc) right bundle branch block (RBBB), an SIQIIITIII pattern, inverted T waves in the second and third precordial leads and/or an increase in the frontal QRS axis of 20 degrees C or more were found in 71 patients (82%). The prevalence of c and inc RBBB and the increase in frontal QRS axis correlated with the extent of embolization (angiographic or scintigraphic score), while the appearance of the SIQIIITIII pattern did not. No patient with a vascular obstruction of two thirds or more had an ECG free of signs of right ventricular strain. In 9 of 11 embolectomized patients with c RBBB, c RBBB disappeared within 24 h postoperatively. Among patients with an embolization of 45% or more, those with c RBBB had a shorter symptom duration, fewer embolic episodes and a lower pulmonary artery pressure than those without c RBBB. As ECG abnormalities were transient and changing in nature, serial ECG recordings are recommended. Pronounced ECG signs of right ventricular strain should, as they may reflect both massive and short-lasting vascular obstruction, arouse the suspicion of pulmonary embolism suitable for embolectomy.

Adolescent↗
PubMedDate not supplied

Floating right heart thrombi and pulmonary embolism: diagnosis, outcome and therapeutic management.

The aim of this study was to analyze clinical and echographic findings and to assess therapeutic management in 14 floating right atrial thrombi diagnosed with systematic echocardiography in 200 consecutive patients with proven pulmonary embolism. Auscultatory findings were abnormal in 7 cases, 4 of them showing signs of tricuspid obstruction. Echocardiography displayed a mobile ovoid, polycyclic or worm-like right atrial mass, always associated with signs of cor pulmonale. Four patients (29%) died, 2 of them before any treatment could be started. Regarding the remaining 10 patients with favorable outcome, surgical embolectomy was carried out in 7. Our data suggest that echocardiographic examination is necessary in all suspected pulmonary embolisms and has to be done quickly for emergency treatment in patients with floating right atrial thrombus.

Adult↗
PubMed1992

Structural changes and recovery of function after arterial injury.

Repair and remodeling processes initiated by arterial injury are thought to be critical in the pathogenesis of important vascular disorders. However, how these processes are related to specific types of injury is not well defined. Consequently, we compared arterial responses to several types of injury. Segments of rabbit carotid arteries were injured by intraluminal passage of an inflated embolectomy catheter, by hyperdistending the arteries with sterile saline, or by flushing them briefly with Triton X-100. Ballooning and Triton treatment removed the endothelium while imposing hyperdistending or nonhyperdistending injury on the vessel media. Hyperdistension with sterile saline caused medial injury but only transient and focal endothelial denudation. All modes of injury caused medial damage that was repaired within 2-7 days as assessed by vessel wall DNA content and synthesis and by capacity to contract. In addition, ballooned arteries recovered their capacity to exhibit diameter reductions induced by decreased blood flow once the endothelium had regenerated. The two injuries that caused endothelial denudation, ballooning and Triton treatment, resulted in equal intimal thickening after 6 weeks despite lower short- and long-term rates of cell replication after Triton-induced injury. Only ballooning resulted in chronic turnover of intimal smooth muscle cells after injury. No neointimal proliferation followed hyperdistension with saline despite significant medial injury. These latter findings suggest that even severe medial injury does not lead to intimal proliferation in the absence of endothelial denudation.

Animals↗
PubMed1992

In vivo effect of insulin on the acute proliferative response of the rat aorta to injury.

The objective of our study was to investigate the effect of hyperinsulinemia associated with either euglycemia, hypoglycemia, or hyperglycemia on the short-term mitotic activity of arterial smooth muscle cells (SMCs) after aortic injury. The proliferative reaction of arterial SMCs was provoked by the passage of an embolectomy catheter with a tightly inflated balloon. DNA synthesis was measured as DNA specific activity after incubation of the aorta in a medium containing 3[H]thymidine. Unrestrained rats were rendered hyperinsulinemic (4-7 nM versus 0.3 nM in controls) immediately after aortic injury by insulin infusion (10 units/day) and either euglycemic (about 5.6 mM), hyperglycemic (14-17 mM), or hypoglycemic (about 2.8 mM) by adjusting the flow rate of hypertonic glucose (30% wt/vol) that was infused simultaneously. The infusion was performed via a catheter inserted into the jugular vein and lasted 2 or 4 days after the aortic injury. After the injury, SMC mitotic activity was dramatically increased on day 2 in control rats with deendothelialized aortas and declined between days 2 and 4. In euglycemic-hyperinsulinemic and hyperglycemic-hyperinsulinemic rats, SMC proliferation showed the same pattern as in controls. At no time was a significant difference observed among the three groups of rats. In hypoglycemic-hyperinsulinemic rats, SMC mitotic activity increased to a lesser extent than in controls on day 2 after deendothelialization. These data indicate that hyperinsulinemia with or without hyperglycemia does not stimulate the early stages of arterial SMC proliferation in the rat although a long-lasting effect of hyperinsulinemia cannot be excluded.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Prolonged activation of prothrombin on the vascular wall after arterial injury.

This study was designed to characterize the relative roles of bound Xa/Va and thrombin activity in vascular wall procoagulant activity after balloon-induced injury and the extent to which intravenous aspirin and heparin attenuate procoagulant activity associated with the vascular wall. Abdominal aortic injury was induced in rabbits by overinflation and multiple passages ofa 4F embolectomy catheter. Rabbits were killed 15 minutes or 4, 8, 24, 48, 72, 96, or 120 hours after injury. Aortic segments were incubated ex vivo to define bound procoagulant activity. Thrombin activity bound to the aorta was detected by 4 hours after injury and was most marked over the first 24 hours, as estimated by increases in concentration of fibrinopeptide A during incubation of segments with recalcified barium-adsorbed plasma or activity against the thrombin-synthetic substrate S-2238. Based on comparison with purified human thrombin incubated under the same conditions, a maximum of 0.04 to 0.1 nmol/L per square centimeter of thrombin activity was associated with the vascular wall during the first 24 hours and remained detectable for 72 hours. In contrast, bound Xa/Va complex activity to injured segments was detected within 15 minutes and induced activation of prothrombin added to recalcified barium-adsorbed plasma incubated with injured segments for 96 hours. Aspirin (15 mg/kg) administered 30 minutes before injury attenuated 111In-platelet deposition at 4 hours by 67%, with an associated decrease in bound Xa/Va and thrombin activity at 15 minutes and 4 hours. However, intravenous heparin did not attenuate bound Xa/Va activity at 15 minutes or thrombin activity at 15 minutes and 4 hours. Platelet-dependent bound Xa/Va activity occurs rapidly after arterial injury and may promote thrombin elaboration for up to 96 hours. Bound thrombin activity and de novo thrombin elaboration on the vascular wall may play an important role in the progression of thrombosis and vascular wall remodeling.

Animals↗