A new rotational thrombectomy catheter: system design and first clinical experiences.

PURPOSE: To describe a new catheter for the percutaneous mechanical removal of fresh and organized thrombi, and to assess its efficacy and safety in vitro and in vivo. METHODS: The catheter consists of a coated stainless steel spiral that rotates at 40,000 rpm over a guidewire inside the whole length of an 8 Fr, single-lumen, polyurethane catheter, driving a dual-blade cutting crown. Abraded occlusion material is sucked into the catheter head through distal side holes and transported by the spiral into a reservoir at the proximal end. The efficacy of the device was tested in arterial models and fresh bovine carotid arteries (n = 72). In a clinical pilot study 10 patients (8 women, 2 men; mean age 70.6 +/- 10.1 years) with occlusions of the superficial femoral artery (2-12 cm, mean 5.8 cm), not older than 4 weeks, underwent thrombectomy with the new catheter. RESULTS: In arterial models and bovine cadaver arteries the catheter completely removed fresh thrombi. Occlusion material of higher consistency was cut into particles of 100-500 micron and transported outside. Thrombectomy was successful and vessel patency restored in all 10 patients. The ankle/brachial pressure index significantly (p < 0.0005) increased from 0.41 +/- 0. 18 before intervention to 0.88 +/- 0.15 after 48 hr and to 0.84 +/- 0.20 after 3 months. Two reocclusions occurred within 14 days after the intervention. CONCLUSION: Thrombectomy with the new device appears to be feasible and safe in patients with acute and subacute occlusions of the femoropopliteal artery.

Influence of variability of interpretation of contrast venography for screening of postoperative deep venous thrombosis on the results of a thromboprophylactic study.

To assess interobserver variability of venography for screening for postoperative deep venous thrombosis (DVT), we used 185 bilateral ascending contrast venograms (366 lower limbs) which were performed using the long-leg film technique, in the frame of a trial of the efficacy of two low-molecular-weight-heparin fractions (initial evaluation). These venograms were submitted in a multicenter setting to three further readers who performed a serial scoring as DVT, no DVT or non-evaluable. DVTs were diagnosed in 78, 55 and 59/366 limbs (initial evaluation: 58). The proximal locations of DVTs were 16, 9 and 16 (initial evaluation: 15) and the non evaluable limbs 3, 5 and 18 (initial evaluation: 0). Apparent pairwise agreement between the three readers ranged from 87 to 90% (true coefficient of agreement Kappa 0.63-0.70). It ranged from 89 to 93% (Kappa 0.63-0.74) for the comparison between the readers and the initial evaluation. This considerable degree of disagreement among experienced readers should be taken into account in calculating sample sizes in prospective thromboprophylactic studies. Indeed, one of the two prophylactic regimens proved to be significantly (p = 0.012, p = 0.031, p = 0.049) or non-significantly (p = 0.073) superior to the other one depending upon the reading of venograms.

Venography of the lower limbs. Pitfalls of the diagnostic standard. The ETTT Trial Investigators.

RATIONALE AND OBJECTIVES: Phlebography is considered the diagnostic standard for suspected deep venous thrombosis. The authors studied the inter-observer variability of phlebogram interpretation in the setting of a multicenter therapeutic trial of the thrombolytic agent alteplase. METHODS: The interpretation of 31 pairs of venograms (before and after thrombolytic therapy) was studied by comparing the quantitative Marder's scores which were computed by three experts and the qualitative assessment of phlebographic changes induced by thrombolysis by the panel of experts and by the investigators. RESULTS: Although the scores of the three experts correlated fairly well (r = .67-.82; P < .001), they differed significantly from each other (P < .0001). Substantial differences also were found between local (by investigators) qualitative evaluation of the venographic changes induced by the treatment and central evaluation by the panel of experts (coefficient of agreement kappa = 0.19), local assessment being significantly more optimistic (P = .002) than central judgment. CONCLUSION: Significant differences were observed between assessment of changes in venographic scores after thrombolytic treatment both among three expert radiologists, and between the panel of experts and the local investigators of the multicenter trial. This observation points to the need for an a priori definition of well-characterized decision criteria to allow a valid interpretation of the effects of the therapeutic intervention.

Thrombosis of the popliteal vein.

Among 3,307 consecutive patients (3,556 legs) with deep venous thrombosis, 54 (1.5%) showed an isolated thrombus of the popliteal vein on phlebography. The majority of those had a history of "effort" or long lasting flexion during air or bus travel. Forty-four percent suffered from pulmonary embolism as the first sign of deep venous thrombosis. Functional phlebography demonstrated the primary site of thrombosis at folds forming in the vein wall at flexion. In order to further elucidate the pathogenetic mechanism, 158 popliteal veins were examined phlebographically in different functional states revealing age-related characteristic wall patterns of rings and folds in flexion causing transient impairment of flow. Complementary morphological studies of 120 popliteal veins during autopsy showed a transverse rippling of the vein wall caused by intimal fibrosis and partial atrophy of the media corresponding to the phlebographic findings. It is concluded that microtrauma during effort in combination with impaired venous backflow and fibrotic transformation of the venous wall can lead to thrombus formation in the popliteal vein.

[Percutaneous transluminal coronary angioplasty]. / Die perkutane transluminale Koronarangioplastie.

Since its first application in a patient, PTCA has undergone a tremendous evolution: Based on growing experience and due to technical developments, indications have been markedly extended. Despite the fact that PTCA has been used in more risky situations, the primary success rate has risen and the rate of severe complications has dropped. This evolution is shown based on the Basel experience and on data from Switzerland. The problem of restenosis, however, has not been solved and remains the main problem to be looked for during follow-up of these patients.

Prevention of aortocoronary vein bypass graft occlusion: which antithrombotic treatment and for how long?

The effects of 50 mg aspirin combined with 400 mg dipyridamole were compared with those of standard anticoagulant therapy, in the prevention of aortocoronary vein bypass graft occlusion. Early graft occlusion in 249 patients, with 749 distal vein graft anastomoses, were angiographically assessed 11.5 +/- 2 days after surgery and were almost equal in both treatment groups. In half of the patients in each group, active treatment was replaced by placebo after 3 months. Repeat angiography after 1 year (360 +/- 24 days) showed that more new late graft occlusions occurred in patients with only 3 months active medication (either regimen). The incidence of major complications was significantly higher in patients treated with anticoagulants, with minor side-effects more common in the antiplatelet group. Thus, this antiplatelet drug regimen was as effective as standard anticoagulant therapy in the prevention of early and late bypass graft occlusion, but carried a significantly lower risk of severe complications. In addition, as replacement of active treatment by placebo after 3 months resulted in significantly more graft occlusions, antithrombotic treatment should be continued for at least one year after coronary artery bypass graft surgery.

[How long should antithrombotic therapy be continued following aortocoronary bypass surgery?]. / Wie lange soll die antithrombotische Therapie nach aortokoronarer Bypassoperation fortgeführt werden?

In a prospective randomized trial the effect of prolonged antithrombotic treatment with anticoagulants or antiplatelet drugs (50 mg aspirin + 400 mg dipyridamole daily) on late bypass-graft occlusion was studied. After 3 months active treatment was replaced by placebo in half of the patients. Between the angiographic checkups 2 weeks and 12 months postoperatively, 28/330 (8%) new graft occlusions had occurred on continued therapy, versus 44/319 (14%) on placebo (p = 0.03). This difference was most pronounced in individual grafts (6% vs 12%, p = 0.01), so that fewer patients with 12 months' active therapy had at least one occluded graft (22% versus 32%, p = 0.08). These findings suggest that antithrombotic treatment should not be halted 3 months after CABG surgery but should be continued for at least one year and possibly longer.

[Emergency coronary dilatation in acute myocardial infarct with contraindications to thrombolytic therapy: salvage of the myocardium by early intervention]. / Notfallmässige Koronardilatation beim akuten Myokardinfarkt mit Kontraindikation zur Lysetherapie: Rettung von Myokard durch frühe Intervention.

In 1986/87, emergency-PTCA in acute myocardial infarction was performed in 13 patients in whom thrombolysis was contraindicated. All infarct-related arteries could be opened with PTCA. Patency rate after one week was 94%. Reopening of the vessel resulted in immediate cessation of ischemic chest pain and in stable cardiac rhythm and hemodynamics. Prior cardiopulmonary resuscitation and/or cardiogenic shock did not influence short- or longterm outcome. In nine of eleven patients an improvement of left ventricular function was found after four to six months as compared to one to four weeks after PTCA. The functional result proved to be better if PTCA was performed early; PTCA within 90 minutes was associated with normal left ventricular function. Thus, PTCA is feasible as an emergency procedure in patients with acute myocardial infarction and contraindications to thrombolysis. It can salvage myocardium and improve or prevent severe infarct complications when performed early after onset of pain. Rapid hospital admission through the primary care physician importantly influences the outcome for these patients.

Trial of low-dose aspirin plus dipyridamole versus anticoagulants for prevention of aortocoronary vein graft occlusion.

In a prospective randomised trial, 249 patients who had aortocoronary vein bypass surgery were assigned either to a platelet inhibitory drug regimen or to standard anticoagulant therapy. Treatment was replaced by placebo in half of the patients in each group after 3 months. The platelet inhibitory drug regimen--very low-dose aspirin combined with dipyridamole--was as effective as standard anticoagulant therapy to prevent early and late graft occlusion. Death, myocardial infarction, and severe bleeding occurred significantly more often in patients receiving anticoagulants, whereas mild drug-related gastrointestinal and cerebral side-effects were more common in patients taking platelet inhibitory drugs. Antithrombotic treatment should be continued for at least 1 year after coronary artery bypass graft surgery.

[Etiology and long-term course of subclavian vein thrombosis with reference to acute therapy]. / Atiologie und Langzeitverlauf bei Subclavia-Venenthrombose unter Berücksichtigung der Akuttherapie.

Contrary to deep venous thrombosis of the lower extremity, subclavian vein thrombosis (SVT) is rather rare. Although the problem has been known for more than 100 years, the rarity of its incidence accounts for the persistent uncertainty concerning the indication and modalities of acute therapy as well as the long-term course. In the majority of 96 patients observed between 1976 and 1983 SVT was due to central venous catheter, neoplasm and thoracic outlet syndrome. 2 of 96 patients developed pulmonary embolism. 45 patients without malignancy were available for follow-up studies. Acute therapy included anticoagulation in 27, fibrinolysis in 10 and rib resection in 8 cases. The mean follow-up averaged 6.3 years and confirmed a favorable course independent of the acute therapy modality. There were none of the trophic alterations so often found in the lower extremity and no patient was unable to work as a consequence of SVT. However, minor late sequelae occurred quite frequently: slight symptoms in one third, and minor incapacity for sport in 25% of the cases. 75% of the patients showed clinical signs of stasis, such as venous bypass circulation, edema and/or cyanosis. The average post-thrombotic score (1.3 out of a possible 4) confirms the minor significance of the findings. A rather important reduction in venous backflow was found by plethysmography in 4% of the patients. We favor immediate anticoagulation, mainly to cover the risk of pulmonary embolism. This should be continued for at least 3 months in order to prevent early recurrence of thrombosis.(ABSTRACT TRUNCATED AT 250 WORDS)

[Deep venous thrombosis of the upper extremities]. / Die tiefe Venenthrombose der oberen Extremität.

Deep vein thrombosis of the upper extremity is rare. While its pathogenesis is not always evident, it often occurs in connection with tumors, thoracic outlet syndrome or intravenous catheter therapy. Acute thrombosis of the subclavian vein usually is a clinical diagnosis, but in doubtful cases diagnostic tests such as Doppler ultrasound and/or plethysmography may be useful. If necessary, verification of subclavian vein thrombosis can be done by phlebography. Considering the incidence of thromboembolic complications such as pulmonary embolism, anticoagulation is indicated in all cases of acute thrombosis. Under standard conservative treatment residual symptoms following the venous occlusion are few and the prognosis is favorable. Therefore, invasive treatment such as thrombectomy or thrombolysis should be considered only in special cases.

[Embolization of the bronchial artery in the treatment of severe lung hemorrhage in patients with cystic fibrosis]. / Bronchialarterienembolisation zur Behandlung einer schweren Lungenblutung bei Patienten mit Cystischer Fibrose.

The embolization of corresponding branches of the bronchial artery in the event of severe haemoptysis in patients with cystic fibrosis is an effective measure, well tolerated by these patients. The experience in 5 cases is reported.

[Dipyridamole and low-dose aspirin in patients with aortocoronary bypass--comparison with anticoagulation]. / Dipyridamol und niedrig dosiertes Aspirin bei Patienten mit aortokoronarem Bypass--Vergleich mit der Antikoagulation.

The effects of antiplatelet therapy (AP; dipyridamole 400 mg [beginning 2 days preoperatively] + aspirin 50 mg/day) and anticoagulation (AC) were compared prospectively in 251 patients with coronary artery bypass grafting (CABG). Two weeks postoperatively, 85.2% of AP and 81% of AC patients had all grafts patent with graft patency rates of 93.6% and 91.3% respectively (p = n.s.) Significant differences in favour of AP therapy were found in subgroups with multiple grafts and with low intraoperative graft flow. Up to 3 months postoperatively, severe complications occurred in 22 AC patients (11 bleedings) but only in 9 patients on AP therapy (p less than 0.01). Overall, AP therapy should therefore be preferred to AC in patients with CABG surgery.

Non-invasive grading of aortic regurgitation by Doppler ultrasonography.

Doppler ultrasound without concomitant echocardiographic imaging was used to grade isolated aortic regurgitation in 21 patients. The severity of aortic regurgitation was subsequently graded (from 0 to IV) angiographically. A 2 MHz continuous wave Doppler transducer was placed over the apex of the heart and the beam was aimed parallel to the mitral flow by means of acoustic guidance. Mitral pressure half time was calculated from the analogue maximum velocity tracing and it was less than or equal to 60 ms in 10 controls; 50-120 ms in five patients with grade II, 120-160 ms in nine patients with grade III, and greater than or equal to 160 ms in seven patients with grade IV aortic regurgitation. These results indicate that a semi-quantitative grading of aortic regurgitation may be obtained non-invasively with non-imaging Doppler ultrasonography in patients without concomitant mitral valve disease.