SEPT 1, 1990

patient had a prolonged acute episode which did not respond to repeated 3-litre plasma exchanges over 10 days. Cyclophosphamide 50 mg daily was therefore added to the daily plasmaphereses. The platelet count returned to normal after 10 days, and the dose of cyclophosphamide was reduced after 6 months to 50 mg on alternate days. She has now been in full clinical and haematological remission for 580 days. The pathogenesis of chronic relapsing TTP in adults is uncertain' but may involve autoimmune mechanisms. 2 Immunosuppressive therapy, including prednisolone, azathioprine, and vincristine/" has been effective in some patients and, in a single case of acute TTP, cyclophosphamide combined with splenectomy has been reported to be therapeutic.' In our patient low-dose cyclophosphamide appears to have induced a sustained remission, suggesting it may have a valuable prophylactic role in patients with chronic TTP who have frequent relapses despite conventional therapy. Department of Haematology. University College and Middlesex School of Medicine. London Wl N 8AA. UK




1. Byrnes JJ, Moake JL. 'Thrombotic thrombocytopenic purpura and the haemolyticuraemic syndrome: evolving concepts of pathogenesis and therapy. Clin Haematol

1985; 15: 41}-42.

2. Moake JL, Rudy CK, Troll JH, ct aI. Therapy of chronic relapsing thrombotic thrombocytopenic purpura with prednisone and azathioprine. AmJ Hernatol 1985; 20: 73-79. 3. Gutterman LA, Stevenson TD. Treannent of thrombotic thrombocytopenic purpura

with vincristine. JAMA 1982; 247: I43}-36. 4. Wallach HW, Oren ME, Herskowitz A. Treatment of thrombotic thrombocytopenic purpura with plasma infusion and cyclophosphamide. S()Uth M ed J 1979; 72: 1346-47.

Transcatheter closure of atrial septal defects SIR,-Transcatheter closure of congenital heart defects is done only at a few centres.' The most frequent congenital heart anomaly, atrial septal defect (ASD), is especially amenable to interventional cardiology. We report a new technique for transcatheter ASD closure. We constructed a device consisting of two self-opening umbrellas that are introduced separately along a long guidewire (fig 1). A patch of homologous pericardium is sewn on the male umbrella. This patch is obtained, prepared, and preserved by the method used for aortic-valve homografts. 2 To ensure that the device is centered, compressed 'Ivalon' is placed between the two umbrellas; this swells on contact with blood. A 0·016 inch guidewire 400 em long is advanced from the right femoral vein through the ASD, left atrium, left ventricle, and into the aorta where it is caught and brought out through the left femoral artery with the snare technique.' A catheter is advanced, in a retrograde direction, transarterially over this wire into the left atrium. The male umbrella with the pericardial patch is placed in a 14F 'Teflon' sheath and introduced transvenously over the long guidewire into the left atrium, where it is expanded. A 15 mm piece of ivalon is then passed along the wire through the same sheath into the left atrium. The female umbrella is then pushed into the right

Fig l-ASD device on the guidewire showing pericardial patch on male umbrella (right). compressed ivalon (centre). and female umbrella (left) ,

Fig 2-Diagram showing positioning of device across ASD . Central body of male umbrella is guided by wire into central ivalon channel. NT = nylon thread.

atrium and expanded (fig 2). A metal ball on the guidewire is used to pull the male umbrella from the left atrial side, while the two-channel pusher catheter brings the female umbrella to the male umbrella along the guidewire. Additionally, a nylon thread is attached via the second pusher channel to the female umbrella and ensures manoeuvrability of this umbrella before closure. By this means the two umbrellas interlock at the level of the ASD, compressing the ivalon between them. Since the central body of the male umbrella is passed into the central ivalon channel, the ivalon keeps the umbrella close to the centre of the ASD (fig 2). The arms of the interlocked umbrellas press on the atrial septal wall, firmly fixing the device. The position of the device is confirmed by direct left atrial contrast medium injection before removal of the guidewire through the left femoral artery (fig 3). Once the device is stable the nylon thread is also removed through the pusher catheter and left atriography is again done. This teclmique was used to close an 18-mmASD in a 58-year-old woman with a pulmonary/systemic ratio of 2'3/1 and a pulmonary arterial pressure of 56/17 mm Hg (mean pressure 32). An Inoue balloon' was used to measure the ASD before the procedure. Two umbrellas (diameter 35 mm) and a 25 mm pericardial patch closed the defect completely, leaving no residual shunt. The procedure lasted 117 min. The patient was discharged on the third day. Anticoagulants were given systemically. At three months' followup fluoroscopy and two-'dimensional echocardiography showed a

Fig 3-Selective left atriography after positioning of device and before removal of guidewire. LA= left atrium. RA = right atrium.

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stable position and a good centring of the device. The patient reported symptomatic improvement. This procedure has since been successful in another patient.

Cardiovascular Centre Dedinje,

Beograd, Yugoslavia




in young healthy people, often trained athletes. In such individuals, hypervagotonia may manifest as arrhytlunia, including sinus arrhytlunia, atrioventricular block, or escape idioventricular rhythm as seen here. This case suggests that 24-h Holter monitoring rather than a single ECG should be done when screening very athletic volunteers in drug safety studies. Such precautions would much reduce the risk that ECG abnormalities are falsely attributed to investigational compounds.

*Present address: University of Ottawa Heart Institute, Cardiology Department, Onawa Civic Hospital, Ottawa, Ontario, Canada KI Y 4E9.

J. Lock JE, Cockerham JT, Keane JF, Finley JP, Wakely PE, Fellows KE. Transcatheter umbrella closure of congenital hean defects. Circulation 1987; 75: 59>-99. 2. Collis LJ, Clarke DB, Smith AR. d'Abreu's practice of cardiothoracic surgery. London: Edward Arnold, 1976: 457-{i() 3. Babic UU, Dorms G, Pejcic P, et a1. Percutaneous mitral valvuloplasty: retrograde, transarterial double-balloon technique utilizing the transseptal approach. Cathet Cadi

Transcatheter closure of atrial septal defects.

566 THE LANCET SEPT 1, 1990 patient had a prolonged acute episode which did not respond to repeated 3-litre plasma exchanges over 10 days. Cyclopho...
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