Ernst Schneider

Prospective 12-Year Follow-up Study of Clinical and Hemodynamic Sequelae After Deep Vein Thrombosis in Low-Risk Patients (Zürich Study)

BACKGROUND No prospective study of the long-term sequelae of more than 10 years after acute deep vein thrombosis exists so far. Therefore, 58 low-risk patients with DVT were included in a prospective study to evaluate the natural history of postthrombotic syndrome. METHODS AND RESULTS Clinical and hemodynamic examinations were performed at the time of admission; after 3, 6, and 12 months; after the 2nd, 3rd, 4th, 5th years; and finally after the 12th year. All patients received heparin initially and oral anticoagulants subsequently. After 12 years, 64% of the patients exhibited normal findings. Mild skin changes were found in 28%, marked trophic changes in 5%, and only one venous ulcer occurred. Regular use of compression stockings was reported by 54% of the patients with multilevel thrombosis. Although mean maximum venous outflow was significantly reduced from the acute event to 12 years later (P<.003) compared with the contralateral leg, a significant (P<.05) improvement was observed 6 months later. Recanalization of calf vein thrombosis was detected by Doppler sonography after 3 months. Sixty-four percent of the multilevel thromboses were recanalized completely or in part after 1 year; in 69%, valvular incompetence was found. CONCLUSIONS In contrast to earlier reports, this prospective study up to 12 years after deep vein thrombosis demonstrates a low incidence of postthrombotic syndrome by administration of oral anticoagulants and regular compression therapy. However, the adverse clinical event rate (mortality 14%) and a recurrence rate of 24% show that the prognosis after deep vein thrombosis does not appear favorable even in low-risk patients.

Acute mesenteric ischemia caused by spontaneous isolated dissection of the superior mesenteric artery: treatment by percutaneous stent placement

Abstract. Spontaneous and isolated dissection of the superior mesenteric artery is a rare and often fatal event which has been successfully treated by surgery in several reported cases. We present a patient with acute mesenteric ischemia due to superior mesenteric artery dissection who was successfully treated by percutaneous endovascular placement of a Wallstent.

Magnetic Resonance Angiography Versus Duplex Sonography for Diagnosing Renovascular Disease

Noninvasive testing for renovascular disease is required to identify patients who may benefit from revascularization procedures without exposing an unnecessary amount of patients to the risks of catheter angiography. All available methods of diagnosing renal artery stenosis have significant limitations. We compared a new technique, contrast-enhanced magnetic resonance angiography, with an established technique, duplex ultrasonography, for the detection of renal artery stenosis using catheter angiography as the standard of reference. Eighty-nine patients with clinically suspected renovascular disease underwent duplex renal scanning and contrast-enhanced magnetic resonance angiography. Sixty of these also underwent catheter angiography. All studies were interpreted for the presence of renal artery stenosis blinded to the results of the other imaging modalities. For detection of hemodynamically significant (>/=60% diameter reduction) main renal artery stenosis, sensitivity and specificity were 90% and 86%, respectively, for magnetic resonance angiography and 81% and 87% for duplex sonography. Most false readings involved differential grading of stenoses detected with all 3 techniques. When patients with fibromuscular dysplasia were excluded from the analysis, the sensitivity of magnetic resonance angiography increased to 97%, with a negative predictive value of 98%. Magnetic resonance angiography detected 96% and duplex 5% of accessory renal arteries seen at catheter angiography. Contrast-enhanced magnetic resonance angiography is a useful technique for diagnosing atherosclerotic renovascular disease. It overcomes the major limitations of duplex renal scanning. However, duplex has the advantage of providing hemodynamic information and appears better suited for the assessment of patients with suspected fibromuscular dysplasia.

Fibromuscular Hyperplasia: Extension of the Disease and Therapeutic Outcome

92 patients with fibromuscular hyperplasia (FMH) seen at the University Hospital Zurich were studied. Renovascular FMH was the most frequent manifestation of the disease (89%). FMH of the cerebral arteries was seen in 26%. The intestinal and subclavian arteries were involved in 9% each and the iliac arteries in 5% of the patients. In 2 patients each FMH of the abdominal aorta or the coronary arteries, respectively, was found. 26% of the patients had systemic disease with involvement of 2 or more arteries. Half of the patients with bilateral renovascular disease showed additional extrarenal FMH. All patients with renovascular FMH were hypertensive (mean blood pressure 194 +/- 34/119 +/- 18 mm Hg). Surgery, percutaneous transluminal angioplasty (PTA) and medical therapy were equally effective in controlling blood pressure. The cure rates were 52% in patients undergoing surgery and 50% in those treated with PTA. The complication rate, however, was higher with surgery (11%) than with PTA (3%). 62% of the patients treated medically were normotensive. Major side effects occurred in 4.8%. The outcome of curative interventions (surgery or PTA) was influenced by the extension of FMH. In unilateral disease the cure rate was significantly higher (62%) than in systemic FMH (28%; p less than 0.03). Patients with strict bilateral disease were cured in 50%. We conclude: (a) PTA seems to be the treatment of choice in renovascular FMH because of a high cure and a low complication rate and (b) the outcome of curative interventions seems markedly influenced by the extension of FMH in these patients.

Long-term experience in percutaneous transluminal dilatation of renal artery stenosis

Percutaneous transluminal dilatation was attempted in 65 patients with renovascular hypertension. In five cases (8 percent), percutaneous transluminal dilatation could not be performed for technical reasons. In the remaining 60 patients (35 with atherosclerotic stenosis and 25 with fibromuscular dysplasia), both mean systolic and diastolic pressure fell immediately after percutaneous transluminal dilatation and remained significantly lower for a period of up to five years. Cure rates after a mean control period of 21.6 months were higher in patients with fibromuscular dysplasia (50 percent) than in those with atherosclerotic stenosis (29 percent). Improvement of blood pressure was observed in 32 percent of patients with fibromuscular dysplasia and in 48 percent of patients with atherosclerotic stenosis. Follow-up angiography in 33 cases showed occlusion of the dilated artery in two patients and recurrence of slight renal artery stenosis in nine patients. Successful redilatation could be performed in five of these cases. Furthermore, renal vein renin determinations were only of limited diagnostic or prognostic value. These results document the good long-term effect of percutaneous transluminal dilatation in patients with renal artery stenosis. Percutaneous transluminal dilatation should, therefore, be the favored procedure in patients with renovascular hypertension.

Femoro-popliteal artery thrombolysis with intra-arterial infusion of recombinant tissue-type plasminogen activator--report of a pilot trial

Recombinant tissue-type plasminogen activator (rt-PA) was infused at a rate of 10 mg/h into 50 thrombosed femoral and popliteal arteries. Patency was restored in 43 but a secondary angioplasty led to 2 reocclusions and in 3 patients early rethrombosis occurred. A favourable clinical result was thus obtained in 38 patients (76%). Thirteen bleeding complications occurred in 10 patients, mainly haematomas at puncture sites. One patient required blood transfusion for gastro-intestinal bleeding from a previously unknown ulcer. The angiographic recanalisation rate in 16 patients who received a slower infusion of rt-PA (5 or 3 mg/h) was 94% and the clinical success rate in this series was 81%. However, the incidence of bleeding complications was not decreased by the slower infusion rate. The data obtained confirm the feasibility of rt-PA thrombolysis in peripheral arterial thrombosis and warrant a comparative study with streptokinase.

Can MR Measurement of Renal Artery Flow and Renal Volume Predict the Outcome of Percutaneous Transluminal Renal Angioplasty

AbstractPurpose: Predicting therapeutic benefit from percutaneous transluminal renal angioplasty (PTRA) in patients with renal artery stenosis (RAS) remains difficult. This study investigates whether magnetic resonance (MR)-based renal artery flow measurements relative to renal parenchymal volume can predict clinical outcome following PTRA. Methods: The data on 23 patients (13 men, 10 women; age range 47–82 years, mean age 64 years) were analyzed. The indication for treatment was hypertension (n = 18) or renal insufficiency (n = 5). Thirty-four cases of RAS were identified: bilateral disease was manifest in 11 and unilateral disease in 12 patients. The MR imaging protocol included a breath-hold, cardiac-gated cine phase-contrast sequence for renal flow measurement and a fast multiplanar spoiled gradient-echo sequence for renal volume measurement. MR measurements were performed on the day prior to and the day following PTRA. Clinical success was defined as (a) a reduction in diastolic blood pressure > 15% or (b) a reduction in serum creatinine > 20%. Kidneys were categorized as normal volume or low volume. A renal flow index (RFI) was calculated by dividing the renal flow (ml/min) by the renal volume (cm3). Results: Clinical success was observed in 11 patients. Twelve patients did not benefit from angioplasty. Normal kidney volume was seen in 10 of 11 responders and in 8 of 12 nonresponders, resulting in a sensitivity of 91%, specificity of 33%, a positive predictive value (PPV) of 56% and a negative predictive value (NPV) of 80%. A RFI below a threshold of 1.5 ml/min/cm3 predicted successful outcome with 100% sensitivity, 33% specificity, 58% PPV, and 100% NPV. The combination of normal renal volume and a RFI below 1.5 ml/min/cm3 identified PTRA responders with a sensitivity of 91%, a specificity of 67%, a PPV of 71%, and a NPV of 89%. PTRA resulted in a greater increase in renal flow in responders compared with nonresponders (p < 0.001).Conclusion: A combination of cine phase-contrast MR renal flow and parenchymal volume measurements enables identification of patients benefiting from PTRA with a high sensitivity and NPV, but only moderate specificity and PPV.

Late acute thrombotic occlusion after endovascular brachytherapy and stenting of femoropopliteal arteries

OBJECTIVES The aim of this article is to underline the importance of this complication after endovascular brachytherapy (EVBT) and intravascular stenting of the femoropopliteal arteries occurring in a running randomized trial. BACKGROUND Endovascular brachytherapy has been proposed as a promising treatment modality to reduce restenosis after angioplasty. However, the phenomenon of late acute thrombotic occlusion (LATO) in patients receiving EVBT after stenting is of major concern. METHODS In an ongoing prospective multicenter trial, patients were randomized to undergo EVBT (iridium 192; 14 Gy at a depth of the radius of the vessel +2 mm) after percutaneous recanalization of femoropopliteal obstructions. Of the 204 patients who completed the six months follow-up, 94 were randomized to EVBT. RESULTS Late acute thrombotic occlusion occurred exclusively in 6 of 22 patients (27%) receiving EVBT after intravascular stenting and always in concomitance with reduction of antithrombotic drug prevention (clopidogrel). Conversely, none of the 13 patients with stents and without EVBT (0%; p < 0.05) and none of the 72 patients (0%; p < 0.01) undergoing EVBT after simple balloon angioplasty presented LATO. CONCLUSIONS Late thrombotic occlusion occurs not only in patients undergoing EVBT after percutaneous coronary recanalization but also after stenting of the femoropopliteal arteries and may compromise the benefits of endovascular radiation. The fact that all our cases with LATO occurred concomitantly with stopping clopidogrel may indicate a possible rebound mechanism. An intensive and prolonged antithrombotic prevention is probably indicated in these patients.

Immediate and long-term outcome of upper extremity balloon angioplasty in giant cell arteritis.

Purpose: To review the immediate and long-term results of subclavian, axillary, and brachial artery balloon angioplasty (PTA) in giant cell arteritis (GCA). Case Reports: Four patients (3 men; mean age 65±8.9 years) with upper limb claudication due to GCA underwent PTA for 2 stenoses and 1 occlusion of the subclavian artery, 6 stenoses and 2 occlusions of the axillary artery, and 2 stenoses of the brachial artery. Patients received steroids prior to the intervention, and steroid treatment was continued for at least 2 years. All procedures were performed successfully with no residual stenosis. At follow-up after 2 years (n=2), 5 years (n = 1), and 10 years (n = 1), no significant recurrent stenoses were detected by duplex scanning. Conclusions: PTA is a safe and effective therapy for stenotic lesions and occlusions of the upper limb arteries due to GCA. The long-term results seem to benefit from postprocedural therapy with steroids and aspirin.

Cure and Improvement of Renovascular Hypertension after Percutaneous Transluminal Angioplasty of Renal Artery Stenosis

In the present study we report our long-term experience in 82 patients with renovascular hypertension (48 with atherosclerotic stenosis, 34 with fibromuscular dysplasia) who were followed up for a mean observation period of 23.6 months after percutaneous transluminal angioplasty (PTA) of renal artery stenosis. Our results show a highly significant decrease in mean systolic and diastolic blood pressure. Cure rates were slightly higher in patients with fibromuscular dysplasia (41% cured, 47% improved) than in those with atherosclerosis (23% cured, 54% improved). Kidney function significantly improved in patients with cure, remained stable in those with improvement and worsened in cases classified as unimproved. These results document the good long-term effect of PTA on blood pressure and kidney function in patients with renal artery stenosis.