[Pelvic and leg vein thrombosis in azygous and hemi-azygous vein continuity syndrome and complete agenesis of the inferior vena cava]. / Becken- und Beinvenenthrombose bei Vena azygos- und Vena hemiazygos-Kontinuitätssyndrom und kompletter Agenesie der Vena cava inferior.

A patient with a complete agenesis of the inferior vena cava is presented. In this rare anomaly the blood of the pelvic veins is drained through the dilated venae lumbales, vena azygos and vena hemiazygos into the superior vena cava. The malformation was detected within the scope diagnostics of deep vein thrombosis. The diagnosis was made by sonography, computed tomography and magnetic resonance angiography.

[Angiography during interventional procedures with carbon dioxide (CO2) (carbo-angiography) in patients with increased contrast media risk]. / Interventionsbegleitende Angiographie mit Kohlendioxid (CO2) (Carboangiographie) bei Patienten mit erhöhtem Kontrastmittelrisiko.

Within the last 18 months we examined 130 patients with known complications or contraindications using iodinated contrast media for angiography by using carbon dioxide as contrast agent in digital subtraction angiography technique. These were diagnostic pelvis-leg angiographies (n = 106) with simultaneous consecutive interventional radiologic therapy in 68 cases. In 19 dialysis access fistulas 11 angioplasties were performed in the same session. In 5 cases of renal allografts no interventional radiologic therapy was necessary. For CO2 application an electronic controlled special injector was used. Carbon dioxide has a number of advantages: no adverse reactions, nonallergenic and can be used several times without increasing risks and is cost-saving. CO2 angiography is a sensitive method, for detection vessel wall processes below the diaphragm. It can replace conventional angiography.

[Carbon dioxide as an alternative contrast medium in peripheral angiography]. / Kohlendioxid als alternatives Kontrastmittel für die periphere Angiographie.

A closed gas pressure pistol was used in 50 patient CO2 angiography as a supplementary method to conventional injection with liquid contrast medium. These were diagnostic pelvis-leg angiographies (n = 36), therapeutic angiographies (n = 8), haemodialysis fistulas (n = 3), suspected stenosis of a renal transplant artery (n = 1) and suspected renal artery stenosis (n = 1). 246 renal angiography series were performed with CO2. Dosages varied in accordance with the imaged vascular area between 10 ccm;(shunt imaging) and up to 100 cm3 (pelvis-leg angiography), at pressures between 400 mbar in case of haemodialysis fistulas up to 2000 mbar in the pelvis-leg area. Short-term feeling of fullness and even nausea were accompanying symptoms in 4 patients. The image quality was slightly inferior to that of conventional contrast medium images due to an elevated signal-to-noise ratio. Injector-monitored CO2 angiographies enabled imaging of the distal aorta or of peripheral vascular sections, imaging of the upper extremity and presentation of kidney transplants in patients with a relative or absolute contraindication to iodised contrast media.

[Determinants of arterial embolism with special reference to atheromatous changes of the thoracic aorta]. / Determinanten arterieller Embolien unter besonderer Berücksichtigung atheromatöster Veränderungen der thorakalen Aorta.

Potential sources of arterial embolism were evaluated with special emphasis on aortic atheromatosis in patients who underwent transesophageal echocardiography for various clinical reasons. Among 375 patients, 166 had suffered from cerebrovascular disease or peripheral embolism and 209 were free from symptoms of embolism. Univariate analysis revealed that atheromatosis of the aortic arch and descending aorta as well as cardiac thrombi, aneurysms of the interatrial septum and arterial hypertension were significantly more common in patients who had a history of embolism or ischemic stroke. In a stepwise multiple regression analysis, aortic arch atheromatosis (odds ratio 1.7, 95% CI 1.1-2.6), cardiac thrombi (odds ratio 4.1, 95% CI 1.7-9.8), atrial septal aneurysm (odds ratio 3.0, 95% CI 1.2-7.8) and arterial hypertension (odds ratio 1.8, 95% CI 1.1-3.0) were determined as independent predictors of embolic symptoms. We conclude that atheromatous lesions of the aortic arch are an independent risk factor for arterial embolism and ischemic stroke among other well known sources of embolism.

[Doppler ultrasound monitoring during vascular interventions]. / Dopplerultraschallmonitoring während Gefässintervention.

Doppler ultrasound examination as diagnostic device in angiology yields only discontinuous information on flow velocities in vessels during insonation with hand-held probes. Continuous insonation and therefore determination of flow velocities in arteries are necessary to evaluate flow disturbances and changes of flow velocities during radiologic invasive interventions, i.e. implantation of stents, during percutaneous transluminal angioplasty therapy or local lysis. This modification of Doppler ultrasound examination is already used in neurosurgery for permanent monitoring of flow velocities in large brain vessels in one or both hemispheres during therapy. In our institute we developed a probe holder device to fix a miniature Doppler ultrasound probe (8-MHZ pulsed-wave probe) on the skin surface. Therefore continuous insonation during the manipulations is easy to realize. Information about complications such as occlusions, thrombi, emboli and changes in flow velocity is immediately present on the screen. We have monitored 40 patients during radiologic interventional therapy in arteries of the lower limb. Complications during the interventions were detected immediately and could be corrected.

Systemic embolism in aortic arch atheromatosis.

The role of aortic atheromatosis as a risk factor for systemic embolism and its relationship to other potential sources of embolism was examined in 335 patients undergoing transoesophageal echocardiography for various clinical reasons. Multiple logistic regression analysis revealed a significant correlation between embolism and moderate (atheroma protruding less than 5 mm into the aortic lumen, grade 2) to complex (atheroma protruding at least 5 mm into the vessel lumen with or without mobile components, grade 3) atherosclerosis of the aortic arch. Odds ratios were 4.0 for grade 2 atheromatosis (95% CI 1.1-14.4; P < 0.05) and 9.7 for grade 3 atheromatosis (95% CI 1.5-61.0; P < 0.05). Other significant associations were found with cardiac thrombi (odds ratio 4.0, 95% CI 1.7-9.3; P < 0.005) and hypertension (odds ratio 1.8, 95% CI 1.0-3.3; P < 0.05). In a subset of 163 patients in whom results of an ultrasound examination were available, atherosclerosis of the carotid arteries was another significant marker of embolism (odds ratio 2.0, 95% CI 1.2-3.3; P < 0.01). In conclusion, aortic arch atheromatosis, which was predominantly recognized in patients with cerebrovascular events of undetermined cause, seems to carry a risk of embolism that is comparable to cardiac and carotid atherosclerosis.

[DSA with mechanically injected carbon dioxide. Animal experimental results]. / DSA mit maschinell injiziertem Kohlendioxid: Tierexperimentelle Ergebnisse.

Carbon dioxide was used as an intra-arterial contrast medium by mechanical injection in 10 pigs. 127 angiographic examinations of 114 vascular territories were carried out and 93 were successful. A mechanism providing even gas volumes was chosen to obtain reproducible volume and pressures when using a compressible medium such as gas. Gas pressure is exponentially correlated with volume and volumes of 20-50 cm3 at 1000 mbar adequate for filling various infradiaphragmatic vascular areas. In parenchymatous organs, gas filling is seen only as far as third order arteries. The reason for this is escape of gas through preexisting arteriovenous fistulae into the efferent veins.

[Carbon dioxide as an irrigation medium for percutaneous angioscopy]. / Kohlendioxid als Spülmedium für die perkutane Angioskopie.

Since technical progress has allowed the development of small and flexible endoscopes, percutaneous, transluminal angioscopy promises to be a diagnostic and therapeutic tool. Nevertheless, the main problem is to obtain a satisfactory bloodless visual field. The saline solutions used for this purpose present problems with hypervolaemia, insufficient clearance, and decreased refraction. We investigated a CO2 application system for angioscopy that allows the reproducible injection of variable quantities of gas, pressure, and injection time. In 10 pigs undergoing angioscopy, CO2 was injected through a Swan-Ganz catheter under blockade of the distal aorta. Using a bifemoral approach, the application of gas and the blocking balloon were controlled by an automatic gas injector. The CO2 was injected through the tip of the catheter with a constant flow and a variable pressure and time. The angioscopy procedures were videotaped. With small volumes of carbon dioxide (approximately 50 cm3; 1000 mbar application pressure) a column of gas can be created which, unlike liquids, completely displaces blood from the vessels and allows for several minutes a bloodless inspection of the aorta and the side branches without blood mixture. Carbon dioxide application allows safe and successful percutaneous angioscopy under optimal conditions if the quantities of gas, pressure, and injection time are adjustable. The tested gas injection device fulfills these conditions.

[Thrombotic and thromboembolic occlusions of leg arteries and bypasses. Short-term versus long-term lysis]. / Thrombotische und thrombembolische Beinarterien- und Bypassverschlüsse. Kurzzeit- versus Langzeitlyse.

Since thrombolytic therapy is less invasive than operative thrombectomy, it is often used as initial treatment for thrombotic or thrombo-embolic occlusions of lower limb arteries or by-passes. We compared four patient groups with acute and subacute occlusions: 1. 19 patients with occluded by-passes treated by rapid lysis using 15.5 (2.5-35) mg rt-PA. 2. 12 patients with by-pass occlusions treated with initial rt-PA in a dose of 6.5 (2.5-12.5) mg followed by prolonged lysis with 5.6 (2.5-10) x 10(6) units of urokinase. 3. 16 patients with arterial occlusions treated by rapid lysis with 15 (2.5-25) mg rt-PA. 4. 14 patients with arterial occlusions given 10.5 (2.5-60) mg rt-PA followed by overnight treatment with 5.9 (2.5-15) x 10(6) units of urokinase. For by-pass recanalisation, prolonged lysis overnight had a success rate of 83% (10/12) which was better than short term lysis with a success rate of 74% (14/19). Similar results were obtained in arterial occlusions with a success rate of 86% (12/14) compared with 69% (11/16). Long term lysis did, however, have significantly more complications. In about one-third of cases further procedures had to be used in addition to lytic therapy.