Accuracy of visible retinal emboli for the detection of cardioembolic lesions requiring anticoagulation or cardiac surgery. Retinal Emboli of Cardiac Origin Study Group

AIM

To determine the accuracy of visible retinal emboli as a diagnostic "test" for the likelihood of receiving anticoagulation or cardiac surgery based on the results of transthoracic echocardiography, in the setting of acute retinal arterial occlusion.

METHODS

A multicentre retrospective diagnostic study at Kingston Eye Centre, Queen's University, Kingston, Ontario; Wills Eye Hospital, Philadelphia; Ottawa Eye Institute, Ottawa, Ontario; and the Halifax Infirmary, Halifax, Nova Scotia of 104 patients with both embolic and nonembolic acute retinal arterial obstruction who underwent transthoracic echocardiography was performed, to determine the accuracy of visible retinal emboli as a diagnostic "test" for anticoagulation or cardiac surgery. Anticoagulation or surgical intervention on the basis of abnormalities was detected solely through the technology of transthoracic echocardiography.

RESULTS

41 patients had visible retinal emboli (calcific, cholesterol, or fibrin). The remaining 63 had no evidence of embolic disease. The sensitivity of emboli for the likelihood of a patient receiving anticoagulation or cardiac surgery was 50%. The specificity, positive predictive value, and negative predictive value were 62%, 15%, and 90%, respectively. The likelihood ratio (LR = 1.31) obtained given the presence of a visible retinal embolus was neither clinically nor statistically significant (LR+ve = 1.31; 95% CI (0.91, 3.16)). This likelihood ratio, when applied to a patient with a pretest probability of 50%, results in a post-test probability of 56.7%.

CONCLUSIONS

These results demonstrate that the presence of a visible retinal embolus should not be the sole determinant of whether to order transthoracic echocardiography, as the likelihood ratio for a patient receiving anticoagulation or cardiac surgery, given the presence of a visible retinal embolus was only 1.31.

A comparison of recombinant urokinase with vascular surgery as initial treatment for acute arterial occlusion of the legs. Thrombolysis or Peripheral Arterial Surgery (TOPAS) Investigators

BACKGROUND

Recent controlled trials suggest that thrombolytic therapy may be an effective initial treatment for acute arterial occlusion of the legs. A major potential benefit of initial thrombolytic therapy is that limb ischemia can be managed with less invasive interventions.

METHODS

In this randomized, multicenter trial conducted at 113 North American and European sites, we compared vascular surgery (e.g., thrombectomy or bypass surgery) with thrombolysis by catheter-directed intraarterial recombinant urokinase; all patients (272 per group) had had acute arterial obstruction of the legs for 14 days or less. Infusions were limited to a period of 48 hours (mean [+/-SE], 24.4+/-0.86), after which lesions were corrected by surgery or angioplasty if needed. The primary end point was the amputation-free survival rate at six months.

RESULTS

Final angiograms, which were available for 246 patients treated with urokinase, revealed recanalization in 196 (79.7 percent) and complete dissolution of thrombus in 167 (67.9 percent). Both treatment groups had similar significant improvements in mean ankle-brachial blood-pressure index. Amputation-free survival rates in the urokinase group were 71.8 percent at six months and 65.0 percent at one year, as compared with respective rates of 74.8 percent and 69.9 percent in the surgery group; the 95 percent confidence intervals for the differences were -10.5 to 4.5 percentage points at six months (P=0.43) and -12.9 to 3.1 percentage points at one year (P=0.23). At six months the surgery group had undergone 551 open operative procedures (excluding amputations), as compared with 315 in the thrombolysis group. Major hemorrhage occurred in 32 patients in the urokinase group (12.5 percent) as compared with 14 patients in the surgery group (5.5 percent) (P= 0.005). There were four episodes of intracranial hemorrhage in the urokinase group (1.6 percent), one of which was fatal. By contrast, there were no episodes of intracranial hemorrhage in the surgery group.

CONCLUSIONS

Despite its association with a higher frequency of hemorrhagic complications, intraarterial infusion of urokinase reduced the need for open surgical procedures, with no significantly increased risk of amputation or death.

Early complete recanalization in internal carotid artery embolism treated with high-dose t-PA: a sequential angiographic study in a novel model of embolism in rats

Complete early recanalization rate of human internal carotid artery embolic occlusion treated with thrombolytic drugs is low. To study factors related with this difficulty to recanalize we have developed a novel model of rat ica embolism using a fragment of human embolus. In 50 male Wistar rats the ica was embolized through the external carotid artery with a fragment of an embolus obtained from a human embolectomy passed through a catheter of 0.8 mm diameter. Recanalization was assessed by sequential angiograms from 15 to 120 min after embolization. Reperfusion was classified according to TIMI grades. Emboli of either 1 (group 1) or 2 mm (group 2) in length were cut. In group 1, four groups of nine animals each were treated, 15 min after embolization, with i.v. t-PA at doses of 1 mg/kg, 10 mg/kg and 20 mg/kg or saline. In group 2 there was one control group of seven animals treated with saline and another of seven animals treated with 10 mg/kg t-PA. Complete recanalization (TIMI grade 3) within the first 30 min was present in two animals treated with 10 and 20 mg/kg. Complete recanalization within the first 60 min was present in 0% of controls and animals treated with 1 mg/kg and in 44% of the 10 and 20 mg/kg groups (P<0.05 in chi-square test). Incomplete recanalization (TIMI grades 0, 1 and 2) occurred in 33%. In group 2 total recanalization occurred in 1/7 controls and in 3/7 animals receiving 10 mg/kg of t-PA. Early (60 min) complete i.v. t-PA induced internal carotid artery embolic recanalization is low with standard doses and increases moderately when high doses are used. Further increases in the dose do not improve recanalization rate, which is not clearly influenced by embolus size. Complete recanalization within 30 min, the period after which infarction develops in the rat, is uncommon in our model.

Successful intraarterial thrombolysis of an ischemic limb four days after laparoscopic cholecystectomy

Intraarterial thrombolysis is usually contraindicated after abdominal surgery because of the risk of bleeding. However, it is a highly effective treatment for embolic acute limb ischemia, particularly for clearing the distal vessels. We report a case in which intraarterial thrombolysis was safely used 4 days after laparoscopic cholecystectomy in a patient with an acutely ischemic leg due to embolus.

Aortic valve stenosis as a cause of major systemic embolism--a case report

This is the first documented case of a patient suffering from embolic occlusion of the left brachial artery caused by a large embolus growing on a lesion of a stenosed calcified aortic valve. Supported by their own additional observations the authors suggest that severe calcified aortic valve stenosis should be considered as an indication for anticoagulation in the period before surgical valve replacement.

Vascular complications of thoracic outlet syndrome

Vascular complications of thoracic outlet syndrome are uncommon but may result in significant long-term disability. This report documents a retrospective review of 17 such patients. Ten patients presented with acute onset of upper extremity swelling and axillosubclavian vein thrombosis. One patient presented with chronic, intermittent arm swelling and subclavian vein stenosis. Three patients presented with acute symptoms of upper extremity emboli, and three presented with chronic arm claudication. Cervical ribs were discovered in four patients with arterial symptoms and in no patients with venous symptoms. All ten patients with acute venous thrombosis underwent successful thrombolysis, with venous stenosis uncovered in 8. Thrombolysis was also performed for two patients with arterial emboli. All 17 patients underwent surgical decompression of the thoracic outlet, 16 via a supraclavicular approach and one via a transaxillary approach. One subclavian arteriotomy with endarterectomy and one resection of a subclavian artery aneurysm were performed at the time of decompression. Repeat venography after decompression demonstrated persistent venous stenosis in one patient that was treated with balloon angioplasty and stenting. After a mean of 22 months' follow-up, 12 patients had no residual symptoms, and 5 had experienced significant improvement of symptoms. In conclusion, a combined approach of thrombolysis and surgical decompression of the thoracic outlet provides a salutary outcome in a majority of patients.

[Renal artery embolism treated by selective intra-arterial infusion of tissue plasminogen activator: report of 2 cases]

Two cases of renal artery embolism treated by selective intra-arterial infusion of tissue plasminogen activator (t-PA) are reported. A 74-year-old woman with atrial fibrillation presented with left flank pain of 54-hour duration. Selective renal angiography revealed embolic obstruction of multiple segmental arteries in the left kidney. She was treated by one-shot intra-arterial t-PA infusion (8,000,000 units) and intravenous heparinization (25,000 units/3 days). Although fibrinolysis was successful except for most distal arterial branches, complete recovery of renal function was not obtained. A 66-year-old man presented with complete obstruction of left main renal artery. He had hyperthyroidism and atrial fibrillation. At 75 hours after onset of left flank pain, he was treated by one-shot intra-arterial t-PA infusion (18,000,000 units) and intravenous heparinization (4,000 units/24 hours). His renal function was recovered completely. Selective intraarterial t-PA infusion is considered an effective treatment for renal artery embolism.

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.

Bilateral macular holes resulting from septic embolization

PURPOSE

To report a previously undescribed cause of bilateral macular hole formation.

METHOD

Case report.

RESULTS

Septic emboli were noted at the center of the macula in both eyes of a 32-year-old man with acute bacterial endocarditis. Bilateral full-thickness macular holes later developed at the site of these retinal lesions.

CONCLUSION

This case represents the first report of fundus lesions in septicemia resulting in full-thickness macular hole formation.

Long-term results after surgery for acute mesenteric ischemia

BACKGROUND

Acute mesenteric ischemia is associated with high mortality rates, and little is known about the long-term prognosis of patients after initially successful surgical intervention.

METHODS

Ninety patients were treated by vascular reconstruction or bowel resection, or both, between 1972 and 1993. The overall mortality was 66%. The outcomes and rehabilitational statuses of those 31 patients who were discharged from the hospital were analyzed retrospectively. Anticoagulation consisted of vitamin K antagonists in patients with venous thrombosis and arterial embolism or inhibition of thrombocyte aggregation in patients with arterial thrombosis and nonocclusive mesenteric ischemia.

RESULTS

In 31 patients discharged from the hospital venous thrombosis, arterial embolism, arterial thrombosis, and nonocclusive disease occurred in 19, 5, 5, and 2 patients, respectively. The 2- and 5-year survival rates were 70% and 50% and mainly related to cardiovascular comorbidity and malignant disease. Only one patient died after a recurrent attack of arterial mesenteric thrombosis. Twenty percent of the patients suffered from chronic short bowel syndrome after extensive bowel resection, but none required permanent parenteral nutrition.

CONCLUSIONS

Under appropriate anticoagulation there is a remarkably low risk of recurrent mesenteric ischemia. The impaired life expectancy of long-surviving patients is mainly due to cardiovascular comorbidity and malignancies.

Free-floating thrombus and embolic risk in patients with angiographically confirmed proximal deep venous thrombosis. A prospective study

BACKGROUND

A free-floating thrombus (FFT) is often considered to be a risk factor for pulmonary embolism (PE), despite adequate anticoagulation therapy, in patients with proximal deep venous thrombosis.

METHODS

Ninety-five patients underwent prospective assessment according to the presence (FFT group [n = 62]) or absence (occlusive thrombus group [n = 28]) of an FFT. On day 1, color venous duplex scanning, venography (reference method), perfusion lung scanning, and, if results of the lung scan were abnormal, pulmonary angiography were performed. On day 10 (range, days 9-11), the lung scan was repeated, as well as pulmonary angiography if the lung scan demonstrated impairment. A 3-month clinical follow-up visit was scheduled. Five patients were retrospectively excluded from analysis for uncertain diagnosis of FFT. Patients were treated with intravenous unfractionated heparin sodium adjusted for activated partial thromboplastin time (n = 1) or subcutaneous low-molecular-weight heparin (n = 89) (nadroparin calcium, 225 Institut Choay factor Xa inhibitory units per kilogram for 12 hours). Warfarin sodium therapy was initiated on day 3 (range, days 2-4).

RESULTS

Both groups were well-matched according to age, sex, risk factors, and delay from onset of symptoms to treatment. Positive and negative predictive values of color venous duplex scanning for the diagnosis of an FFT were 91% and 55%, respectively. On admission, PE prevalence was 64% in the FFT group (40 of 62 patients) and 50% in the occlusive thrombus group (14 of 28 patients) (P = .19). Two patients were excluded on follow-up analysis (range, days 9-11) for preventive vena cava filtering (due to major bleeding in 1 and cholecystectomy in the other); the recurrent rate of PE was 3.3% in the FFT group (2 of 61 patients) and 3.7% in the occlusive thrombus group (1 of 27 patients). No symptomatic recurrent PE occurred between day 10 (range, days 9-11) and 3 months. Four patients died of evolutive neoplasm after hospital discharge.

CONCLUSIONS

No higher risk for PE was observed in patients with free-floating proximal deep venous thrombosis; anticoagulant therapy should prevent recurrent PE in such patients.

[Treatment of peripheral arterial embolisms. Our case series and review of the literature]

Acute arterial obstruction of the limbs represents one of the most frequent events in Emergency Surgery. In 95% of the cases, the cause has to be searched in embolus parting from the heart in patients with rheumatic or fibrillary disease. Currently the two therapeutic methods used for peripheral arterial obstruction are thrombolytic therapy and surgical dysobstruction using Fogarty's catheter. The Authors compare the two methods on the basis of their experience in 129 cases underlying how the thrombolytic therapy (Urokinase, Streptokinase) should be instituted in the early hours from presentation of symptoms, otherwise, the possibility of revascularization will heavily drop. Better results are obtained by positioning a catheter under radiologic guide for intra-arterial infusion. The Authors also believe that up-to-date the surgical approach with Fogarty's catheter represents one of the best procedures, either for its feasibility of for the costs of the thrombolytic therapy. Furthermore, the thrombolysis may be not complete, and account for possible haemorrhagic complications.

Matas Lecture. Heparin--controversies and misconceptions

The previous dogmas regarding heparin therapy are currently being challenged. It is apparent that the experimental work on which guidelines for heparin therapy are based do not necessarily have any relevance clinically. Once clotting has been initiated, there are multiple factors that result in a relative refractory response to heparin anticoagulation. In addition, it is now apparent that heparin's effect cannot be accurately monitored with current tests of anticoagulation. Most importantly, the risk of bleeding does not correlate with heparin levels but with clinical risk factors and to the presence or absence of functioning platelets. For this reason, sufficient heparin should be given initially to ensure that clotting is under control. If this is not done, all of the risk of heparin anticoagulation is assumed with none of the benefit. Life-threatening clotting conditions require high doses of heparin, equivalent to those required for cardiopulmonary bypass. Even though there is no good laboratory test available to ascertain the adequacy of anticoagulation, assessment of the clinical response is sufficient. When heparin levels are adequate, clinical improvement is evident as manifest by decreased pain and improvement in well-being, cardiac function, and/or collateral flow.

Neuroprotective properties of a protein kinase inhibitor against ischaemia-induced neuronal damage in rats and gerbils

1. The neuroprotective properties of fasudil (HA1077), a novel protein kinase inhibitor, were evaluated in two animal models of cerebral ischaemia: transient bilateral carotid artery occlusion in Mongolian gerbils and cerebral microembolization in rats. 2. The cytoprotective effect of fasudil on delayed neuronal death in gerbils was compared with the effects of nimodipine, a calcium channel antagonist and ozagrel, a thromboxane A2 synthetase inhibitor. The average of the neuronal cell density in the ischaemic control group was 17.8 +/- 2.1 cells mm-1, whereas fasudil (30 mg kg-1) significantly diminished the loss of CA1 neurones with the average of the neuronal cell density of 101.0 +/- 22.0 cells mm-1; nimodipine (10 mg kg-1) and ozagrel (30 mg kg-1) did not significantly protect against the ischaemia-induced neuronal loss. 3. In the rat model, the effects of fasudil on the histological and neurological consequences of cerebral microembolization produced via the injection of microspheres were examined. Twenty-four hours after the injection of microspheres into the internal carotid artery, all animals in the control group showed typical symptoms of stroke. Neurological function was significantly improved in the fasudil-treated animals. In the controls, the infarcted area in a cortical slice selected to include the hippocampal area was 0.25 +/- 0.01 cm2 (mean +/- s.e.mean) (43.9 +/- 2.4% of cortical section of the half hemisphere); the difference was significant compared to the mean area of 32.7 +/- 2.8 and 21.5 +/- 4.8% observed in rats treated with fasudil (3, 10 mg kg-1), respectively. Fasudil (10 mg kg-1) significantly suppressed the increased water content in ischaemic brain tissues (saline-treated rats, 82.4 +/- 0.2% vs fasudil-treated rats, 81.0 +/- 0.4%). 4. These results suggest that: (i) various protein kinases are involved in the pathogenesis of ischaemic injury; and (ii) the inhibition of protein kinases may be efficacious in preventing neuronal death, thus improving neurological function in the brain damage associated with ischaemic stroke.

[Systemic venous thrombolysis with rt-PA in arterial embolism of the legs in the elderly]

Lower limb arterial embolism with blockage of a proximal artery is still a significant use of mortality, especially in elderly subjects. The excellent results achieved in acute myocardial infarction by the use of recombinant tissue plasminogen activator (rt-PA) have prompted us to apply this agent systemically i.v. in elderly patients with probably cardiogenic arterial embolism of the lower limbs. Out of 14 patients in our care, 9 have been submitted to this treatment after careful selection, and in 7 total or partial recanalization of the vessel has been achieved thus saving the limb involved. It can therefore be concluded, even on the basis of the small number of cases, that in selected cases thrombolytic management is possible, while avoiding the hemorrhagic complications attending arterial thrombolysis. This treatment can be applied in hospitals lacking the resources of angiographic diagnostics. The mechanism of action of rt-PA is such that at the doses administered critical changes of blood clotting parameters are not to be feared. Venous systemic thrombolysis can be performed mainly in elderly subjects whose precarious conditions may be upset by manoeuvres involving bleeding, sophisticated diagnostic or surgery.

Peripheral arterial occlusions: local low-dose thrombolytic therapy with recombinant tissue-type plasminogen activator (rt-PA)

OBJECTIVE

To study the efficacy and risks of local thrombolytic therapy of peripheral arterial occlusions using rt-PA.

DESIGN

This open study was performed in one clinic in Munich, Germany.

METHODS

288 patients suffering from occlusions of the lower limb arteries were subjected to 336 treatments performed with a permanently controlled technique. In a short pilot study 10mg rt-PA/h were administered for 5 h but in the majority of the cases only 2.5mg/h were administered for a maximum of 5 h. The average total dose of rt-PA was 2.97mg and the average time for lysis was 78 min.

RESULTS

43 (84.3%) out of 51 embolic occlusions and 168 (71.5%) out of 235 thrombotic occlusions were recanalised with a cumulative patency of 95% and 79.7% respectively after 2 years. One systemic bleeding occurred in the pilot study with 10mg rt-PA/h whereas with the 2.5mg/h dosage no systemic bleeding or embolism occurred in the 315 treatments. There were no deaths during hospitalisation. Six major and two forefoot amputations were necessary. Thirteen patients required a bypass operation and one an embolectomy. The advantages of our controlled technique are: short duration of treatment, small doses of activating agent, an accurately directed pathway with the possibility of dilating stenoses during the same session, no danger of systemic bleeding or embolism and, therefore, good prospects of success with minimal risk.

CONCLUSION

The use of rt-PA for local lysis substitutes the inadequate tissue activator available for effective spontaneous lysis and is, therefore, almost physiological. The effect of a very low dose of rt-PA was as good as that of higher doses.

Intra-arterial fibrinolytic treatment for mesenteric arterial embolus: a case report

The diagnosis of mesenteric ischemia is based on acute clinical awareness of the condition and confirmed by angiography or laparotomy. The standard treatment is abdominal exploration with resection of the gangrenous segment of the bowel or embolectomy of the superior mesentery artery, or both. Alternative treatment such as intra-arterial thrombolysis may be considered in selected patients. A 66-year-old man with a history of atrial fibrillation presented with abdominal pain. Angiography documented an embolus in both the ileocolic artery and a branch of the right renal artery. The patient was treated with selective intra-arterial infusion of streptokinase. The abdominal pain resolved. Repeat angiography showed lysis of both emboli.

Thrombolytic therapy of right heart emboli-in-transit

Currently, no consensus exists for the appropriate treatment of echocardiographically diagnosed mobile right heart masses giving rise to a high suspicion of migrant thromboembolism in patients with pulmonary embolism. This may lead to unnecessary delay in the implementation of the most appropriate treatment for these patients. Several earlier studies have supported the beneficial role of thrombolytic therapy. We report on an additional two patients with mobile right heart thromboemboli, refractory to systemic anticoagulation, who recovered quickly after initiation of thrombolytic therapy.