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PubMed1990

Distal embolization during mechanical thrombolysis: rotational thrombectomy vs. balloon angioplasty.

To determine the incidence and extent of distal embolization during percutaneous transluminal balloon angioplasty (PTA) and rotational thrombectomy (PRT), we collected, filtered, and weighed the distal effluent of acute thrombotically occluded canine arteries following mechanical thrombolysis. PRT (n = 11) and PTA (n = 10) were equally effective in recanalizing occluded vessels (91% vs. 90%) and reduced percent diameter stenosis to a similar degree (97 +/- 6% to 8 +/- 11% and 100 +/- 0% to 17 +/- 23%, respectively). Distal embolization following mechanical intervention was observed in 10 of 10 and 8 of 9 arteries recanalized with PRT and PTA, respectively. The mean weights of collected emboli were similar between the two groups (18 +/- 24 mg vs. 37 +/- 79 mg, PRT vs. PTA, P = NS), although the range of size and weight of thromboemboli was larger in the PTA group (0-206 mg vs. 2-51 mg, PRT). Angiographically defined residual thrombus was significantly less frequent in arteries recanalized with PRT as compared with PTA (10% vs. 55%, P = 0.03). In summary, PRT and PTA are equally effective in recanalizing acutely occluded canine arteries and result in similar reductions in percent diameter stenosis. Each intervention results in distal embolization of thrombi. PRT is associated with a reduced incidence of angiographically evident residual thrombus at the site of arterial injury and may avoid embolization of large fragments occasionally produced by PTA. Thus PRT may serve as a useful alternative to coronary angioplasty during acute myocardial infarction.

Angioplasty, Balloon↗
PubMed1979

Reformation of gap and tight junctions in regenerating liver after cholestasis.

Morphometric analysis of the alterations in interhepatocyte junctions induced by bile duct ligation revealed that after 48 h, during which time the serum bilirubin increased 6 to 8 fold, the membrane area occupied by gap junctions on the apico-lateral and medio-lateral sides decreased from 3.6% in controls to 0.02% in the ligated group. The strands of the zonulae occludentes were reduced in number and showed increased discontinuities. Within 45 min of recanalization of the common bile duct, clusters of particles appeared within and adjacent to the tight junctional areas or in the lateral hepatocyte membrane. Subsequently, the particle aggregations localized in the apico-lateral membrane areas increased in number and size becoming finally indistinguishable from those of controls within 96 h after the onset of recanalization. The zonulae occludentes also rearranged and reestablished their original structure during this period. The serum bilirubin fell to normal within 24 h of recanalization. It is concluded that metabolic and ultrastructural restitution associated with the recanalization of the ligated bile duct have no strict temporal correlation to one another. These studies provide further evidence that alterations in gap and tight junctions induced by pathological processes, e.g. during bile duct ligation, are completely reversible when regeneration occurs.

Animals↗
PubMed1982

[Fibrinolytic therapy of lower limb deep vein thrombosis with urokinase (author's transl)].

In 81 patients with deep vein thrombosis of the lower limb, urokinase therapy was performed in combination with heparin according to a new regimen at higher dosages. When urokinase was administered at an initial maintenance dosage of 1,000-2,000 IU/kg/h (loading dose 150,000-250,000 IU), phlebographically documented complete or partial recanalization could be observed in 68% of the cases. The higher dosage schedule induced a more pronounced deobliteration especially in treatment of iliac vein thromboses (67% recanalization) in comparison to the lower dosage regimen (only 43% recanalization). Nearly comparable therapeutic results could be achieved in therapy of popliteal or saphenous vein thromboses. The data suggest that the higher dosage schedule examined here is indicated in treatment of extensive and large volume thromboses. The dosage of urokinase was further adjusted to attain a reduction of fibrinogen to 50-100 mg/dl. The concentration should not fall below 50 mg/dl. Therapy with urokinase proved practicable. Serious side effects did not occur. 8.6% of the patients showed hematuria and 6% a decrease of the Hb by more than 2 g/dl. The high proportion of older thromboses and the only low rate of recanalization (23%) in these cases suggest the necessity of an early commencement of fibrinolyses in therapy of deep vein thrombosis.

Anticoagulants↗
PubMedDate not supplied

Intravenous and local intraarterial tissue-plasminogen activator in a rabbit model of acute thromboembolic stroke: angiographic comparison.

The aim of early thrombolytic therapy in acute stroke is to obtain early recanalization of occluded cerebral arteries and prevent or reduce irreversible ischemic brain damage. In this study, Seldinger technique and digital subtraction angiography were used to verify thromboembolic occlusion of the common carotid artery by an autologous 12-hour-old thrombus in 28 rabbits. Thirty minutes after embolization, 2 mg/kg of recombinant tissue-plasminogen activator (rt-PA) was delivered intravenously by way of the femoral vein in group A (n = 8) and through a local intraarterial infusion in group B (n = 8). Twelve control animals received an equivalent volume of saline intravenously (group C, n = 6) or by local intra-arterial infusion (group D, n = 6). A comparison of posttreatment angiographs of the treatment groups and the control groups was used to demonstrate reperfusion induced by thrombolytic therapy. None of the control animals showed any evidence of recanalization. Both intravenously (group A) and intra-arterially (group B) treated animals achieved 100% recanalization, although the average time to recanalization was significantly longer in group A (P = .01; 123.7 vs 82.5 min). These results suggest that local intra-arterial administration of rt-PA within 30 minutes produces more rapid reperfusion compared with the intravenous route. Further studies and additional treatments are needed to widen the therapeutic window and decrease hemorrhagic side effects.

Angiography, Digital Subtraction↗
PubMed1998

[Clinical results of acute closing aortic dissection].

The therapeutic outcomes of 43 patients with acute closing aortic dissection treated during the past 10 years were evaluated. The patients consisted of 30 men and 13 women with a mean age of 65 +/- 9 years. Ten were classified as Stanford type A, and the remaining 33 as type B. During follow-up (6 to 120 months; average 55 months), recanalization and an enlarged ulcer-like projection (ULP) were observed in 5 and 2 type a patients. Although recanalization was not observed in type B patients, enlarged ULP was observed in 10 of them, in 6 of whom developed aneurysm. During the follow-up period, ULP was observed at 30 sites in 26 patients. Monitoring the change in ULP over time showed that the ascending and the proximal descending aorta frequently tended to be enlarged and progressed to aorta frequently tended to be enlarged and progressed to aneurysm. Surgery was performed in 3 patients with recanalization, 5 with enlarged ULP, and 3 with atheroscloerotic aortic aneurysm. Although one patient died of cerebral complications, the other 10 patients showed favorable postsurgical courses. Among 8 patients who died, the actuarial survival rate was favorable, being 96, 91 and 83% at 1, 3 and 5 years. However, the survival rate free from complications related to aortic dissection, defined as rupture, ercanalization, enlarged ULP and aneurysmal change, was 78, 58 and 54% at 1, 3 and 5 years, indicating that aortic dissection-related complications are likely to develop within 3 years. This being the case, conservative therapy may be selected for closing aortic dissection when there are no serious complications in the acute phase. However, closely following patients with diagnostic imaging techniques is essential as there may be complications such as recanalization or enlarged ULP. Such complications should be surgically treated because they may affect long-term prognosis.

Aged↗
PubMed2007

Endovascular treatment of intracranial aneurysms with matrix coils: immediate posttreatment results, clinical outcome and follow-up.

INTRODUCTION: Endovascular aneurysm repair with coils has become a safe and effective alternative to surgical clipping. Efforts have been made to create coils that will facilitate aneurysm healing and reduce recurrence. The purpose of this study was to review the safety and durability of our aneurysm treatment using Matrix coils. METHODS: A total of 39 aneurysms in 38 patients, aged 30 to 77 years, were treated using Matrix coils in 42 procedures. Two procedures were unsuccessful, and 12 were done using only Matrix coils. Aneurysm volume, packing density and percentage length of Matrix coils were calculated. The treatment results, procedural complication rate and clinical outcome were analyzed. Follow-up examinations were available for 34 procedures with a mean follow-up of 4.9 months (maximum 13.5 months). RESULTS: Angiographic results were similar to those following the use of platinum coils, with complete occlusion or a residual neck in 82.5% of procedures. Six procedures (14%) were complicated with platelet aggregation. Recanalization occurred in 32% of the patients. Nine patients (26%) had major recanalization and were retreated. One patient had a re-bleed 5 months after the treatment resulting in severe disability. The mean packing density of 39.2% in the recanalized aneurysms was similar to that in the nonrecanalized group. CONCLUSION: In our series, treatment with Matrix coils had a complication rate similar to that reported with platinum coils. However, we had a higher percentage of major recanalizations requiring retreatment. We believe that the absorption of the polymer contributes to the failure of formation of a stable scar within the aneurysm.

Adult↗
PubMedDate not supplied

A new porcine sponge material for temporary embolization: an experimental short-term pilot study in swine.

PURPOSE: To evaluate the safety and efficacy of a porcine-derived gelfoam, Curaspon, for the temporary occlusion of the visceral arteries. METHODS: Curaspon was used for the selective embolization of segmentary hepatic, unilateral polar renal, and single lumbar arteries of 10 pigs under general anesthesia. Sequential angiographic checks were carried out and the pigs killed between 3 days and 2 weeks later. Macroscopic and microscopic studies using standard techniques were used to evaluate the immediate efficacy of embolization, duration of and completeness of recanalization on angiography, macroscopic appearance of target-organ ischemia, and microscopic analysis of inflammatory reaction. RESULTS: Immediate arterial occlusion was obtained in all cases. Renal arteries showed a total recanalization in 63% of cases on day 7 and 100% on day 14. Total hepatic recanalization was obtained in 100% of animals on day 7. All lumbar arteries were recanalized on day 14. Microscopic analysis in the kidney revealed a mild inflammatory reaction and a progressive lysis of the Curaspon (87% of samples at day 3 showed a persistence of Curaspon and 5% at day 14). In some cases, localized and partial destruction of the arterial wall was visualized. In the liver the same patterns were observed but resolved more completely and more rapidly. CONCLUSIONS: Curaspon is an efficient material for the temporary occlusion of visceral and parietal arteries in pigs. However, arterial aneurysms were observed and a relationship of these with the material cannot be excluded.

Animals↗
PubMed1999

Embryogenesis of pancreaticobiliary maljunction inferred from development of duodenal atresia.

The embryogenesis of pancreaticobiliary maljunction is inferred from the embryogenesis of duodenal atresia. The epithelial cells of the duodenum begin to proliferate and completely plug the lumen, but a process of vacuolation recanalizes the duodenum. Recanalization of the common duct frequently appears with two lumina and openings into the duodenum with two orifices. These two major canals create a narrow segment of the duodenum and this narrow zone is the area in the duodenum that is most prone to faulty recanalization and atresia formation. A bifid biliary system inserts at blind upper and lower pouches of the duodenum, and the common bile duct inserts in a Y fashion. The common bile duct inserts at the stenotic segment, and the end result is a T-shaped formation in patients with duodenal stenosis. During the development of the bile duct, abnormal fusion may occur between the bile duct and branches of the right ventral pancreatic duct. The site in the bile duct where a branch of the pancreatic duct joins is likely to develop atresia due to disturbance of the recanalization process, as seen in duodenal atresia. Severe impairment of vacuolation causes divided atretic bile duct at the site where the pancreatic duct inserts in a Y-fashion into the upper and lower bile duct. Moderate impairment of vacuolation causes a stenosis at the site where the pancreatic duct inserts in a T-shape, with a moderate dilatation of the bile duct.

Choledochal Cyst↗
PubMed1984

Percutaneous transluminal coronary angioplasty in acute myocardial infarction.

Percutaneous transluminal coronary angioplasty (PTCA) has, in general, been restricted to therapy for patients with angina pectoris. Thrombolytic therapy and guide wire recanalization have been used to recanalize coronary arteries in patients with evolving myocardial infarction. Recently we and others have examined the use of PTCA to recanalize the acutely occluded artery associated with the early evolving phase of myocardial infarction. PTCA was performed as definitive therapy in eight patients with acute myocardial infarction. Seven of these had totally occluded arteries to the region of infarct. The infarct-related artery was open within 20 minutes in each of these cases. PTCA recanalization resulted in evidence for reperfusion in each case. Residual stenoses either were not present or were minimal. The procedure was well tolerated. These preliminary results suggest that PTCA may be a reasonable alternative to intracoronary thrombolytic therapy in certain patients with acute evolving myocardial infarction.

Adult↗
PubMed1983

Coronary reperfusion and Bezold-Jarisch reflex (bradycardia and hypotension).

This study reports the occurrence of bradycardia and hypotension (Bezold-Jarisch reflex) induced by myocardial reperfusion. Among 92 patients undergoing interventional catheterization for intracoronary thrombolysis in an early phase of acute myocardial infarction, left anterior descending, right coronary, and left circumflex (LC) arteries were identified as the "infarct vessel" in 44, 41, and 7 cases, respectively. The Bezold-Jarisch reflex occurred in 15 of 23 patients (65%) after right coronary recanalization and in 1 of 34 patients after left anterior descending recanalization. The reflex also was observed in 4 (22%) of 18 patients with nonoccluded or nonrecanalized right coronary arteries. The average time from onset of symptoms to right recanalization was significantly shorter (p less than 0.01) among patients in whom the reflex did not develop. Atropine, postural changes, or temporary pacing, or all 3, were generally sufficient to control symptoms. The findings of this study are substantially parallel to those reported by others and confirm that reperfusion of the inferoposterior myocardium is capable of stimulating a cardioinhibitory reflex. Follow-up data available in 15 patients with occluded and recanalized right coronary arteries indicate that the occurrence of the Bezold-Jarisch reflex after reperfusion is not a reliable predictor of myocardial salvage.

Aged↗
PubMed1985

Intracoronary thrombolytic therapy in acute myocardial infarction: a prospective, randomized, controlled trial.

A prospective, randomized trial was designed to assess the efficacy of intracoronary thrombolytic therapy with streptokinase (STK) in acute myocardial infarction. Sixty-four patients with acute myocardial infarction were randomized within 6 hours of onset of symptoms to 1 of 3 groups. Sixteen patients were treated by conventional means (control group). Nineteen patients underwent coronary arteriography and received corticosteroids and intracoronary and intravenous nitroglycerin (NTG group). Twenty-nine patients received management identical to that of the NTG group, with the addition of intracoronary STK therapy (STK group). Recanalization was demonstrated in 21 of 29 patients (72%) in the STK group. Global and regional ejection fraction (EF) was determined by radionuclide ventriculography before any intervention and 7 to 10 days later. No significant improvement in global EF was achieved in the control and NTG groups. In STK patients as a group, global EF did not increase significantly; however, in patients recanalized with STK, EF improved from 42 +/- 17% to 49 +/- 16% (p = 0.023). All groups showed wide variability of response. Improvement in global EF of more than 5% was noted in 44% of patients recanalized with STK. When subgrouped on the basis of initial global EF of 45% or less or more than 45%, only patients recanalized with STK with an initial EF of 45% or less had an improved global EF (from 30 +/- 10% to 42 +/- 10%, p = 0.015).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Electrical thermal angioplasty: catheter design features, in vitro tissue ablation studies and in vivo experimental findings.

A prototype electrical thermal tip catheter has been developed for ablation of atherosclerotic plaques. The operating principle is based on establishing an electric arc between a central electrode and the inside of an enclosing metallic tip to convert electrical energy to thermal energy. The metal tip catheter can be heated rapidly and boils water in a saline bath with less than 1 W of power. In vitro studies, using human atherosclerotic aortic segments, demonstrated that effective tissue ablation required more power in saline than in air (more than 9 W vs less than 1 W). The rate of tissue ablation varied with the amount of power delivered and the catheter tip pressure against tissue. In a saline field, 2-mm thickness aortic wall segments were consistently perforated in 3 seconds when 15 W of power and 20 g/mm2 of pressure were applied. Using an atherosclerotic rabbit, in vivo electrical thermal angioplasty (3 W of power for 10-second treatment sequences) was performed in obstructed iliofemoral vessels after mechanical recanalization was attempted. Of the 7 vessels that were more than 50% narrowed (compared with contiguous normal vessel diameter), mechanical recanalization was effective in only 1, but thermal angioplasty resulting in an increased lumen diameter was successful in 6 others. The recanalized segments were 8 to 10 cm; gross morphologic and histologic examination of recanalized vessels demonstrated little or no thermal injury. In addition, significant cholesterol-laden plaques remained in the vessel lumen, which appeared to have been compressed and displaced laterally.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1989

Optimal criteria for rapid detection of myocardial reperfusion by creatine kinase MM isoforms in the presence of residual high grade coronary stenosis.

Analysis of isoforms of MM creatine kinase (CK) in plasma is being developed as a means for rapid detection of coronary recanalization in patients given thrombolytic agents. To determine whether flow-limiting residual stenosis typical of that seen in patients affects plasma isoform profiles, stenosis sufficient to preclude reactive hyperemia was induced in dogs before coronary occlusion, followed by recanalization in 2 h. Plasma activities of the MM CK isoform released from myocardium (MM3) and its two conversion products elaborated sequentially (MM2 and MM1) were assayed in serial samples with a rapid quantitative chromatofocusing procedure. Reperfusion in 10 dogs shortened the mean intervals (+/-SD) to the occurrence of peak MM3 activity (3.7 +/- 0.9 h), peak MM3 expressed as a percent of total CK activity (MM3%, 2.5 +/- 0.3 h) and the maximal ratio of MM3 to MM1 (2.7 +/- 0.3 h) compared with results in 10 control dogs without reperfusion. Nevertheless, the appearance of these peaks was delayed by 8% to 57% when residual stenosis was present. In contrast, the rate of increase of MM3% was delineated before the peak, was fivefold greater with recanalization (1.19 +/- 0.46 versus 0.26 +/- 0.11% min-1 in control dogs) and was not attenuated by residual stenosis. Thus, this criterion appears capable of delineating recanalization early after thrombolysis whether or not high grade residual stenosis is present.

Animals↗
PubMed1990

Early coronary reperfusion blunts the procoagulant response of plasminogen activator inhibitor-1 and von Willebrand factor in acute myocardial infarction.

The effects of early coronary recanalization on the plasma levels of two procoagulant acute phase proteins, the fastacting plasminogen activator inhibitor and von Willebrand factor, were investigated in 24 patients with myocardial infarction receiving intravenous recombinant tissue-type plasminogen activator (rt-PA) within 6 h of the onset of symptoms. Coronary angiography was performed before and 90 min after the start of rt-PA infusion. Continuous electrocardiographic recordings and 4 h plasma creatine kinase MB isoenzyme (CK MB) were performed over the first 24 h. Plasma plasminogen activator inhibitor activity, von Willebrand factor and C-reactive protein were measured before rt-PA infusion, daily for the first 3 days and after 90 days. In the entire group, plasminogen activator inhibitor activity peaked at 24 h (day 1), representing a significant increase over values at all other times (p = 0.03). von Willebrand factor was higher in the first 2 days of infarction compared with after 90 days (p = 0.001). C-reactive protein peaked on day 2, with an eightfold increase over values on admission (p = 0.001). In the 16 patients with a patent infarct-related artery at 90 min, infarct size estimated by integrated 24 h CK MB, time for ST segment elevation to decrease to half-maximum and peak C-reactive protein were reduced significantly by more than twofold compared with values in the 8 patients with an occluded artery at 90 min. The patients with early recanalization also had lower plasminogen activator inhibitor activity on day 2 (p = 0.05) and day 3 (p = 0.02) and lower 0 to 72 h averaged von Willebrand factor (p = 0.01). Thus, early coronary recanalization curtails the response of plasminogen activator inhibitor activity and von Willebrand factor to myocardial infarction, most likely by reducing the extent of ischemia and necrosis and the consequent acute phase reaction. By blunting the early postinfarction procoagulant state, prompt recanalization may reduce the risk of thromboembolic complications in the first days after myocardial infarction.

C-Reactive Protein↗
PubMed1989

Angioplasty after thrombolysis in the treatment of evolving myocardial infarction.

Potent pharmacological agents that rapidly induce coronary thrombolysis reduce morbidity and mortality from evolving myocardial infarction especially when administered early after the onset of ischemia. However, recanalization frequently unmasks residual, high-grade stenoses that can impair reflow, predispose to reocclusion, and limit salvage of myocardium. Coronary angioplasty performed immediately after recanalization induced by thrombolysis reduces the severity of stenosis and can enhance salvage. Unfortunately, complication rates are higher with emergency compared with delayed angioplasty. Thus, mechanical recanalization early after thrombolysis should be reserved for patients with signs or symptoms of recurrent ischemia or for those in whom pharmacological recanalization has failed but a large amount of myocardium remains at risk.

Angioplasty, Balloon↗
PubMed2006

ACE gene polymorphisms influence t-PA-induced brain vessel reopening following ischemic stroke.

Angiotensin converting enzyme (ACE) influences vessels tone and the coagulation/fibrinolysis system. The ACE gene I/D polymorphism has been linked with PAI-1 and fibrinogen levels and with Factors VII and X activities. Therefore, we aimed to test whether I/D polymorphism could be related to thrombolysis safety and efficacy. We studied strokes involving the middle cerebral artery (MCA) territory of patients who received t-PA <3 h of stroke onset. Blood samples were obtained before t-PA administration to measure fibrinogen, PAI-1, Factors VII and X. I/D polymorphism was determined by polymerase chain reaction and agarose electrophoresis. Recanalization rates were serially evaluated by Transcranial Doppler. Among 96 included patients the genotype frequency was: DD=33.3%, ID=57.3% and II=9.4%. A strong association was found between DD homozygous and successful recanalization rates (DD=69.2%, ID+II=31.6%, p=0.002 at 1 h; DD=91.3%, ID+II=51%, p=0.001 at 6 h; DD=100%, ID+II=72.3%, p=0.003 at 24 h post-t-PA administration). In fact, DD genotype was an independent predictor of recanalization (OR=4.3 95% CI 1.35-13.49, p=0.013). No relation was found between I/D polymorphism and symptomatic hemorrhagic complications (p=0.237). No association between ACE genotypes and Factor VII or Factor X activities, neither with fibrinogen or PAI-1 levels was observed. DD homozygous is strongly associated with MCA recanalization following t-PA treatment. Mechanisms of benefit remain unknown since I/D polymorphism had similar FVII and X activities and PAI-1 and fibrinogen levels in our stroke population.

Acute Disease↗
PubMed2005

Effectiveness of lipid microbubbles and ultrasound in declotting thrombosis.

The objectives of this study were to determine the effectiveness of lipid-encapsulated microbubbles and ultrasound (US) in recanalizing arteriovenous graft thrombi and the effect that tissue attenuation has on the success rate. A total of 55 thrombotic occlusions were created in four canines. The thrombosed grafts were randomly treated with two different 1-MHz US intensities, low (0.4 to 0.6 W/cm(2)) and high (10 W/cm(2)). Intragraft microbubbles were compared with intragraft saline and with the same dose of microbubbles given IV. IV microbubbles were also given both in the presence and absence of a tissue-mimicking phantom. High-intensity US (10 W/cm(2)) with intragraft microbubbles produced significantly higher patency and flow scores than did US with saline (p < 0.01). US with IV microbubbles had higher success rates in recanalizing thrombosed grafts than did US alone at all intensities. Attenuation reduced the rate at which successful recanalization occurred at both low and high intensities. US and microbubbles are capable of recanalizing acute arteriovenous graft thromboses. Higher intensities may be needed in the presence of tissue attenuation.

Acute Disease↗
PubMed1993

A scintigraphic classification of Legg-Calvé-Perthes disease.

The onset of Legg-Calvé-Perthes (LCP) disease, avascular necrosis of the proximal femoral epiphysis, frequently is clinically undetectable for months before presentation. This traditional X-ray methods of diagnosis are insensitive for the diagnosis of early LCP as well as nonspecific for the diagnosis of advanced LCP. The X-ray may remain normal for weeks to months after the onset of LCP, and other disorders (steroid osteopathy, epiphyseal dysplasia) simulate the X-ray appearance of LCP during its later stages. Localization of bone-avid radiopharmaceuticals depends principally on bone perfusion and metabolism. Bone scintigraphy is a highly sensitive and specific means of detecting changes in bone perfusion. An understanding of the vascular anatomy of the pediatric hip and its revascularization mechanisms is essential for correlating the scintigraphic findings with the stages of healing in this disorder. Revascularization of bone can occur by recanalization of existing vessels or by neovascularization through the development of new vessels. Recanalization is a rapidly occurring process (minutes to weeks), whereas neovascularization is a prolonged process (months to years). The recanalization process has a characteristic scintigraphic pattern beginning with the visualization of a "lateral column" and is associated with a good prognosis for eventual outcome in LCP. Neovascularization also has a characteristic scintigraphic appearance ("base filling" and "mushrooming"), which is associated with a poorer prognosis because of the prolonged interval required for healing, which places the femoral head at risk for complications such as fracture, collapse, and extrusion. The scintigraphic staging classification presented here, when correlated with a modified Waldenstrom X-ray staging, readily differentiates three mechanisms of revascularization. The A (allright) track scintigraphic pattern represents the recanalization process, a process of short duration and good prognosis. The B (bad) track scintigraphic pattern represents the process of neovascularization, a process of long duration and poorer prognosis. A third process also is described in which complications of the healing process (collapse, extrusion), particularly during the reabsorptive phases of bone reconstitution when the bone is weakened, can cause conversion from track A to track B. Bone scintigraphy is useful in LCP for its ability to detect the disorder in its initial stages, thus allowing earlier treatment, and to provide prognostic information that may affect therapy.

Child↗