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Four patients with atherosclerotic disease were found to have a recanalized coronary arterial thrombus on angiography. The functional significance of this finding varied. In 2 cases, flow (judged by collaterals) was insignificant in spite of the recanalization. In the other 2, collateral supply had been shown to be absent during the initial stage of thrombosis. In one case, recanalization was confirmed pathologically.
Percutaneous recanalization of femoropopliteal artery occlusions (1-21 cm; median, 8 cm) was attempted in 50 patients. A 2.2-mm-diameter contact probe catheter connected to a continuous-wave neodymium yttrium aluminum garnet (Nd:YAG) laser was used. The laser was activated (15 W, 1-second pulses) only if too much resistance was met. Balloon angioplasty was performed after successful traversal of the occlusion. Primary success was achieved in 40 of 50 patients (80%). In 20 cases, recanalization was achieved mechanically (cold group). In the other 20 cases, recanalization was achieved with the help of laser irradiation (hot group: 15-405 J; median, 90 J). Except for the length of the obstruction (longer in the cold group), the two groups did not differ in baseline characteristics. Neither the length of the occlusion nor the duration of symptoms correlated with failure or success or with the delivered laser energy. Cold and hot groups did not differ with regard to functional improvement and angiographic patency at 3 and 12 months (94% +/- 4). Thus, brief laser activation doubled the cold primary success rate, but the major action of the laser contact probe is mechanical remodeling of the obstruction.
PURPOSE: To evaluate the long-term results of recanalization of occluded iliac arteries with local low-dose thrombolysis, angioplasty, and, if necessary, stent implantation. MATERIALS AND METHODS: Forty-seven patients with acute or chronic occlusions of the common or external iliac artery, or both, underwent local low-dose thrombolysis (n = 47), percutaneous transluminal angioplasty (PTA) (with balloon dilation [n = 43] and rotational angioplasty [n = 30] in the patients in whom a retrograde recanalization was performed), and, if needed, intravascular stent placement (n = 18). Follow-up lasted 3-53 (mean, 21) months. RESULTS: The primary recanalization rate was 98% (46 of 47). The mean ankle-brachial index increased from 0.33 to 0.81 within 14 days after treatment and was 0.76 at the most recent follow-up. Two early (< 14 days) and two late reocclusions (after 24 and 30 months) occurred; one restenosis detected with duplex sonography and angiography was observed after 19 months. CONCLUSION: This therapy represents a true alternative to vascular surgery and a first-line treatment for acute or chronically occluded iliac arteries.
PURPOSE: To determine the patency of Wallstents placed across the venous anastomosis of prosthetic bridge grafts after percutaneous graft recanalization. MATERIALS AND METHODS: Wallstents were placed across 26 lesions at the venous anastomosis of polytetrafluoroethylene (PTFE) grafts in 25 patients (11 men, 14 women; age range, 29-83 years; mean age, 65.4 years) after pulse-spray pharmacomechanical thrombolysis. Indications for stent deployment included acute angioplasty failure, rapid restenosis, and vessel perforation. RESULTS: The initial success rate was 100%. The mean primary graft patency rates (+/- standard error) at 3 and 6 months were 34% +/- 9 and 27% +/- 9, respectively. Secondary patency rates were 77% +/- 8 at 3 months, 72% +/- 9 at 6 months, and 50% +/- 10 at 12 months. Eight of the 26 grafts continued to be used for hemodialysis at the end of follow-up. CONCLUSION: After angioplasty failure or vessel perforation, Wallstent placement at the venous anastomosis of recanalized PTFE grafts can salvage hemodialysis access function. The results of this study indicate that the 1-year secondary patency rate of these grafts is 50%, which approaches the reported rates of patency after balloon dilation as part of percutaneous graft recanalization.
This study was designed in order to assess whether the Iwasaki-Hayashi (IH) catheter can be fixed to the uterine cervix easily and successfully during transcervical fallopian tube recanalization (T-FTR) with fluoroscopic guidance, to try T-FTR in special cases, and to investigate the success rate. The study included 21 infertile women with tubal obstruction, diagnosed by hysterosalpingography examined at least twice to exclude tubal spasm. Using the IH catheter, which proved to be very useful, higher therapeutic efficacy could be obtained. A patient with unilateral proximal tubal obstruction became pregnant following natural fertilization in the fallopian tube which had been recanalized by T-FTR. The success rate of recanalization, the pregnancy rate and the take-home-baby rate were 95.2%/patient, 19.0 and 19.0%, respectively.
BACKGROUND: In the event of early failure of standard extracranial-intracranial arterial bypass, elective but prompt revision surgery is generally attempted under the assumption that early occlusion is permanent. However, little is known about the occurrence of spontaneous revascularization. OBJECTIVE: To estimate the frequency and time course of spontaneous recanalization in primary extracranial-intracranial arterial bypass occlusion and re-evaluate diagnostic and therapeutic options facing spontaneous development. METHODS AND RESULTS: In a retrospective analysis 176 patients with standard superficial temporal artery/middle cerebral artery bypass were included. Twenty-three patients had primary bypass occlusion. In 7 cases spontaneous recanalization was observed. Follow-up of these cases is presented. CONCLUSIONS: Early bypass occlusion has a high incidence of spontaneous recanalization within the first year. In stable patients the first choice may be noninvasive follow-up and postponing revision operation.
41 dogs were subjected to percutaneous arterial embolization of branches or the main trunk of the renal artery with or without prior injury to the kidney. 8 materials were used: homologous blood clot, muscle, fat, fascia, barium sulfate, plain catgut, gelfoam and polyvinyl alcohol (Ivalon). From the angiographic investigation over a relatively long period, it was observed that complete recanalization of the embolized vessels occurred only with blood clot and gelfoam; partial recanalization, with muscle fat and plain catgut; and no recanalization at all with fat, barium sulfate and Ivalon.
BACKGROUND: Coronary collaterals are essential to maintain myocardial function in chronic total coronary occlusions (TCOs). The aim of the present study was to assess the collateral circulation in TCOs before coronary angioplasty and to determine the recruitable collateral perfusion after recanalization by use of intracoronary Doppler flow velocimetry. METHODS AND RESULTS: In 21 patients with TCOs (duration >4 weeks), Doppler recordings of basal collateral flow were obtained before the first balloon inflation. Angioplasty was performed with stent implantation in all lesions. At the end of the procedure, recruitable collateral flow was measured during a repeat balloon inflation. The collateral flow index (CFI) was calculated from the velocity integral during the occlusion/velocity integral of antegrade flow. In 17 of 21 patients, angiography was repeated after 24 hours, and CFI was reassessed. Average peak velocity of collateral flow was 10.9+/-5.6 cm/s with a predominantly systolic flow (diastolic/systolic velocity ratio <0.5) compared with antegrade flow (diastolic/systolic velocity ratio >1.5). After recanalization, the average peak velocity of recruitable collateral flow dropped by >50% to 4.7+/-2.5 cm/s. CFI fell from 0.48+/-0.25 to 0.21+/-0.16 (P:<0.001). There was no further change of CFI during the following 24 hours. CFI was higher in patients with preserved regional ventricular function than in those with akinetic myocardium (0.57+/-0.23 versus 0.38+/-0.12, P:<0.05). CONCLUSIONS: Collateral circulation in TCO provided 50% of antegrade coronary flow. A considerable fraction of collateral flow was immediately lost after recanalization, indicating that TCO may not remain protected from future ischemic events by a well-developed collateral function.
Controlled laser irradiation was used to recanalize atherosclerotic stenoses in vivo and in vitro. In 15 rabbits with atherosclerotic arteries a catheter was positioned in the distal aorta for angiographic examination and as a guide for a small silica optical fiber. Both Nd-YAG and argon lasers were used for recanalization with varying power and duration. As determined by angiographic studies the severity of iliofemoral stenoses in eight 15 arteries decreased from 78 +/- 18% to 32 +/- 11% (mean +/- SD). In one additional artery the stenosis improved from 45% to 25%, but this was associated with perforation. The other six arteries were perforated (two after fiber manipulation, four after laser discharge) without obvious improvement in severity of stenosis. No angiographic loss of distal circulation was noted. To better define tissue- laser interactions in the live-rabbits, lasing of 15 totally occluded atherosclerotic rabbit arterial segments in vitro was done while the optical fiber was advanced or fixed. When the fiber was fixed, serial sections showed that the new lumen was flame shaped. The width and depth of the lumen increased with increasing laser energy. When the fiber was advanced, histologic examination showed a smooth cylindrical vascular channel with limited lateral tissue damage. This study demonstrated that lasers can recanalize atherosclerotic stenoses in a live animal preparation; however, arterial perforation remains a problem.
BACKGROUND: DSPA (Desmodus salivary plasminogen activator) is a new thrombolytic agent corresponding to a natural plasminogen activator discovered in the saliva of the vampire bat Desmodus rotundus. Compared with tissue plasminogen activator (TPA), DSPA, produced in a recombinant cell line, is more fibrin cofactor dependent than TPA. METHODS AND RESULTS: The thrombolytic properties of DSPA and TPA were compared in a canine model of copper coil-induced coronary thrombosis. All dogs received heparin 200 IU/kg IV and SC. Whereas controls did not reperfuse within 180 minutes (none of six), intravenous bolus administration of DSPA at 25, 50, and 100 micrograms/kg resulted in a 100% incidence (6 of 6) of recanalization within 37, 23, and 18 minutes, respectively. TPA at 63 and 125 micrograms/kg reopened the coronaries in 33% (two of six) and 50% (three of six) of cases within 40 minutes. Eighty-three percent (5 of 6) of the arteries were still patent 3 hours after 50 and 100 micrograms/kg DSPA, whereas only 20% (one of five) of all coronaries originally recanalized with both doses of TPA were still open at 3 hours. Plasma levels of alpha 2-antiplasmin decreased significantly only with 125 micrograms/kg TPA. The clearance of DSPA (2.3 to 3.5 mL.min-1.kg-1) was lower compared with TPA (11.4 to 20 mL.min-1.kg-1) due to a prolonged terminal half-life. CONCLUSIONS: In a canine coronary thrombosis model, DSPA exhibited higher potency and recanalized coronary arteries faster and with a lower incidence of reocclusion than TPA. Its properties may translate into a higher efficacy in patients compared with available thrombolytic agents. The long half-life of DSPA may allow for single bolus administration in the treatment of acute myocardial infarction.
Transplantation of blood-derived circulating progenitor cells (CPC) has been shown to improve myocardial regeneration after myocardial infarction. It remains unclear whether CPC transplantation exerts beneficial effects also in patients with chronic myocardial ischemia. We initiated a randomized, double-blind, placebo-controlled study evaluating the impact of intracoronary infusion of CPCs on coronary vasomotion and left ventricular (LV) function in patients after recanalization of chronic coronary total occlusion (CTO). After recanalization of CTO, 26 patients (age, 63+/-2 years; LV ejection fraction, 53+/-2%) were randomly assigned to the treatment (intracoronary transplantation of CPCs) or control group. Coronary flow reserve in response to adenosine (2.4 mg/min) was measured in the target vessel at the beginning of the study and after 3 months. LV function and infarct size were assessed by MRI and metabolism by 18F deoxyglucose positron emission tomography. CPC application resulted in an increase in coronary flow reserve by 43% from 2.3+/-0.3 to 3.3+/-0.5 (P<0.05 versus beginning and control). At 3 months, the number of hibernating segments in the target region (from 2.9+/-0.6 to 2.0+/-0.6 segments, P<0.05 versus beginning and control) had declined in the treatment group, whereas no significant changes were observed in the control group. MRI revealed a reduction in infarct size by 16% and an increase in LV ejection fraction by 14% in the treatment group (from 51.7+/-3.7 to 58.9+/-3.2%; P<0.05 versus beginning and control) because of an augmented wall motion in the target region. Hence, intracoronary transplantation of CPCs after recanalization of CTO results in an improvement of macro- and microvascular function and contributes to the recruitment of hibernating myocardium.
BACKGROUND AND PURPOSE: In thrombolytic therapy for acute ischemic stroke, it is essential to obtain rapid thrombolysis before ischemic neuronal injury occurs. To develop a new technique of thrombolysis for acute ischemic stroke, the effect of transcranially applied ultrasound (TUS) on thrombolysis was examined. METHODS: An occlusion model of rabbit femoral artery was produced with thrombin after establishment of stenotic flow and endothelial damage. After stable occlusion was confirmed, monteplase (mtPA) was administered intravenously, and ultrasound (490 kHz, 0.13 W/cm2) was applied through a piece of temporal bone (TUS group; n=9). The control group received mtPA alone (tissue plasminogen activator [tPA] group; n=12). To verify the efficacy of TUS, femoral artery flow was measured during the procedure. RESULTS: The recanalization ratio was 16.7% (2 of 12) in the tPA group and 66.7% (6 of 9) in the TUS group. The recanalization ratio in the TUS group was higher than that in the tPA group (P=0.03). Patency flow ratio, which was defined as recanalization flow divided by baseline flow, of the TUS group (44.6+/-13.9%) was significantly greater than that of the tPA group (9.9+/-6.8%) at 60 minutes (P=0.025). Patency flow ratio became higher in the TUS group than in the tPA group between 20 and 30 minutes from the start of thrombolysis. CONCLUSIONS: Low-frequency and low-intensity TUS enhanced thrombolysis by mtPA in a rabbit femoral artery occlusion model. This technique should be clinically useful for thrombolysis in acute ischemic stroke.
BACKGROUND AND PURPOSE: Endovascular treatment can improve the outcome of patients treated for ruptured intracranial aneurysms as compared with surgical clipping, but angiographic recurrences are frequent. Endothelial denudation before coil embolization may prevent recanalization and improve results of endovascular treatment. METHODS: We compared angiographic and pathological results 3 months after coil occlusion of paired canine arteries (n=16), with or without previous denudation of the endothelial lining using an endovascular device. The technique was then used to denude the neck of carotid venous pouch bifurcation aneurysms before coil embolization in 8 dogs, and the angiographic evolution at 12 weeks was compared with 7 control aneurysms treated by coiling only. Qualitative scoring systems were used to compare angiographic results with time and neointimal coverage at the neck of aneurysm after necropsy. The evolution of angiographic scores was analyzed using Wilcoxon signed rank tests whereas angiographic and neointimal scores of the 2 groups were compared using the Mann-Whitney test. RESULTS: All arteries embolized with platinum coils recanalized, whereas most arteries (12/16 or 75%) denuded before coil embolization remained occluded at 3 and 12 weeks (P<0.001). Aneurysms treated with coils without previous denudation tended to recur, with angiographic scores significantly worse at 12 weeks as compared with T(0) (P=0.015). Median angiographic and neointimal scores were significantly better at 12 weeks with endothelial denudation (P=0.011 and 0.026, respectively). CONCLUSIONS: Endothelial denudation can prevent recanalization after coil embolization.
BACKGROUND: Patients with isolated middle cerebral artery (MCA) and tandem MCA/internal carotid artery (ICA) obstruction have similar presenting symptoms and stroke severity. We aimed to investigate early recanalization of MCA and clinical outcomes in patients with tandem ICA/MCA obstructions and isolated MCA occlusion. METHODS: Patients with MCA occlusion on pretreatment transcranial Doppler were treated with intravenous tissue plasminogen activator. ICA lesions were detected with carotid duplex. Early neurological improvement (ENI) was defined by reduction of National Institutes of Health Stroke Scale (NIHSS) > or =10 points or total NIHSS < or =3 points. Good outcome at 3 months was a modified Rankin score of < or =2. RESULTS: Among 104 patients, 31% had tandem lesions and 69% had isolated MCA occlusions. Complete recanalization rate was 39% in isolated MCA occlusion group and 9% in tandem group (P=0.002). ENI at 24 hours occurred in 46% of the isolated MCA occlusion group and in 25% of the tandem group (P=0.045). Good outcome was achieved by 30% and 39% respective patients (NS). CONCLUSIONS: The tandem lesion group showed lower early recanalization rate and ENI rate than the isolated MCA occlusion group. Despite this, good outcomes were similar in both groups.
BACKGROUND AND PURPOSE: Previous reports suggest that women achieve better outcome than men after intravenous thrombolysis for ischemic stroke. Coagulation and fibrinolysis differ between sexes. These findings prompted us to investigate possible gender differences in arterial recanalization after intravenous tissue plasminogen activator (IV tPA). METHODS: We identified 100 consecutive patients who presented with acute ischemic stroke and received IV tPA within 6 hours of onset. Only patients with large artery anterior circulation strokes, as determined by MRI/MRA or CT/CTA before treatment, who had follow-up vascular study within 72 hour after treatment were included. We compared demographics, clinical features, admission medications, symptom-to-needle and treatment-to-repeat vascular imaging times, baseline National Institutes of Health Stroke Severity score, radiological and laboratory data, stroke mechanism, and outcome between the sexes. RESULTS: 39 patients met all inclusion/exclusion criteria (22 men and 17 women). The recanalization rate was significantly higher in women (94% versus 59%; P=0.02). This difference remained statistically significant after excluding patients whose strokes were attributed to internal carotid artery occlusive lesions, and when the analysis was limited to those treated within 3 hours of stroke onset. All other confounding variables did not differ significantly between the sexes. CONCLUSIONS: In our cohort, vascular occlusive lesions were more likely to recanalize in women than men in response to IV tPA. These preliminary findings need to be validated in larger prospective studies.
BACKGROUND AND PURPOSE: Recanalization rates after the intravenous (IV) recombinant tissue plasminogen activator (rt-PA) treatment have been poorly studied in acute stroke. METHODS: CT angiography was performed before IV rt-PA in all patients and digital subtraction angiography was undertaken for intra-arterial thrombolysis in cases of no improvement after rt-PA infusion. RESULTS: Forty-five patients were treated with IV rt-PA. Initial CT angiography showed relevant arterial occlusions in 35 patients. Recanalization after rt-PA therapy was demonstrated by digital subtraction angiography in 7 of the 31 patients with the occlusion on initial CT angiography: 2/16 in the internal carotid or proximal middle cerebral artery, 3/11 in the distal middle cerebral artery and 2/4 in the basilar artery occlusion. CONCLUSIONS: The early recanalization rate after IV rt-PA use was very low in cases with large proximal arterial occlusions. CT angiography before IV rt-PA may be useful for the prediction of its efficacy.
In 20 patients with acute major cerebral arterial occlusion, follow-up angiograms were obtained to inspect the occluded artery. These angiograms were compared with brain scans in the fourth week after the stroke. The angiograms revealed that frequent recanalization of the occluded arteries occurred within a week after the onset. On the other hand, brain scans showed the increased uptake of radioisotopes even in the patients with angiographically demonstrated arterial recanalization. The present study clarified that positive scans could be obtained in the patients with and without recanalization, and emphasized the diagnostic value of brain scans in the subacute or chronic stage of cerebral infarction, especially in patients with no arterial occlusion appearing on the angiograms.
Complete recanalization was achieved by intra-aortic infusion of urokinase in a case of complete occlusion of the abdominal aorta. The patient was a fifty-nine-year-old man with atrial fibrillation, hypertension, and diabetes mellitus who was admitted because of intermittent claudication and pain in both lower extremities at rest. Angiography demonstrated complete obstruction of the abdominal aorta, but the bilateral iliac arteries were visualized via collaterals. Urokinase was administered intra-aortically in a total dose of 1,200,000 U during the first day and a total dose of 960,000 U during the second day. The aorta and the iliac arteries recanalized after this treatment, and complete recanalization associated with disappearance of subjective symptoms was observed after one month of treatment with warfarin. The present case suggests the usefulness of intra-arterial infusion of urokinase for the treatment of complete occlusion of the abdominal aorta.