Peroperative measurements of blood flow and pressure in occlusion and/or stenosis of the subclavian artery and the brachiocephalic trunk.

Preoperative haemodynamic studies were performed in 60 out of 64 patients operated upon for occlusive disease of the subclavian artery. The pressure differences over the occlusive lesion were recorded in 53 patients. Blood flow was studied in 56 patients with the aid of electromagnetic flowmetry. The average mean pressure difference was 30 mmHg in 6 patients with occlusion of the brachiocephalic trunk and 20 mmHg in 20 patients with left subclavian artery occlusion. In 3 patients with right subclavian occlusion it was 17 mmHg. The highest individual mean pressure differences were found in patients with multiple occlusive lesions in extracranial cephalic arteries. Stenoses of the brachiocephalic trunk and the subclavian arteries in general caused a lower average mean pressure difference than the occlusions. Vertebral blood flow in cases of occlusion of the proximal part of the subclavian artery was usually reversed.

Regional cerebral blood flow and vertebral angiography at rest and in connection with arm work in patients with the "subclavian steal phenomenon".

Vascular anatomy and haemodynamics of the vertebro-basilar system were investigated by means of vertebral angiography as well as rCBF measurements using the 133Xenon clearance method in 12 patients with occlusive disease of the subclavian artery. Prior to the investigation, the occlusive lesions had been demonstrated by aortocervical angiography, which in 9 out of 12 patients showed reversed vertebral blood flow at rest. All selective vertebral angiographies and rCBF measurements were performed at rest and in connection with graded arm exercise. Patients with the subclavian steal phenomenon were found to have a slightly reduced rCBF. After arm exercise, the intracranial flow velocity of contrast medium in the cerebral vessels remained unchanged, while the velocity of the reversed flow of contrast medium in the vertebral artery was increased. Regional cerebral blood flow in the vertebro-basilar system increased during arm exercise, the average increase being about 16%. The augmentation of flow is probably due to activation of neuronal processes within the brain. The magnitude of these flow alterations in healthy individuals is unknown.

Thrombolytic treatment with i.v. brinase of advanced arterial obliterative disease of the limbs.

The material includes 17 patients suffering from different degrees of chronic peripheral arterial disease (11 chronic patients stage III and IV, two patients with acute arterial occlusion, and four patients stage II). Presence and extent of arterial occlusion was ascertained by initial arteriography. In twelve of the patients amputation had been considered. The patients were treated by a series of i.v. infusions of brinase, a proteolytic enzyme from Aspergillus oryzae. The brinase inhibitor capacity in plasma was determined by the azocollagen technique. Dosage of brinase was calculated to retain a rest-inhibitor capacity in order to avoid free proteolytic activity. In five patients the enzyme was also given preoperatively by intra-arterial instillation prior to a series of i.v. brinase infusions. Thirteen patients showed clinical improvement after brinase treatment. The condition of two patients remained unchanged, and in two patients amputation could not be avoided. In fourteen patients the treatment results were followed by measurement of peripheral systolic blood pressure. In ten patients obvious increase of the peripheral systolic blood pressure was observed. Cutaneous microcirculation was studied in seven patients by i.v. sequential fluorescein angiography and signs of improved microcirculation (appearance time, intensity and/or extent of fluorescence) were found in all examined patients. One patient with acute arterial occlusion of the right leg with obstruction of blood flow from the external iliac artery showed complete disobliteration after a series of i.v. brinase infusions. Bleeding complications associated with brinase treatment were not observed in the material. In three patients brinase treatment was discontinued because of complications (2 brinase, 1 heparin).

Dosage of i.v. brinase in man based on brinase inhibitor capacity and coagulation studies.

In 17 patients a total of 148 brinase infusions were given. All patients but two had anticoagulant treatment (dicoumarol or heparin) during the brinase series. Dosage of brinase was based on determination of brinase inhibitor capacity in plasma (azocollagen technique) prior to infusion of the enzyme. Iv infusion of brinase lowered inhibitors in plasma. Good correlation was found between expected lowering and measured inhibitor values after brinase infusion. The stipulated safety margin for brinase inhibitor capacity could be maintained. alpha 1-antitrypsin showed irregular changes and alpha 2-macroglobulin values were decreased by iv infusions of brinase. Fibrinogen values were somewhat lowered after iv brinase infusion. Values for fibrinogen degradation products increased and the ethanol gelation test became positive. Thrombotest values were lowered and the activated partial thromboplastin time was prolonged in patients receiving dicoumarol and iv heparin respectively. Changes in other coagulation parameters were insignificant. In two patients transient renal failure was recorded, laboratory data indicated intravascular coagulation as a possible cause. None of these two patients were on anticoagulant treatment. One patient developed a haematoma of the forefoot during massive iv heparin treatment during a series of iv infusions of brinase. Bleeding complications due to brinase treatment were not observed.

Oscillography and digital pulse plethysmography in occlusive disease of the subclavian artery and the brachiocephalic trunk. A pre- and postoperative study.

Patients with occlusive disease of the subclavian artery or brachiocephalic trunk were examined by oscillography (17 cases) and digital pulse plethysmography (19 cases) before and after reconstruction of the occluded vessel. Before surgery the oscillographic amplitudes were significantly lower on the occluded than the contralateral arm, with no difference between the registration levels. Shape analysis of the digital pulse curve recordings gave significant differences in all variables, between the occluded and the contralateral arm, inclination time and RAMP25 being most sensitive. Idential studies repeated up to 6 months after surgery demonstrated a marked increase in oscillometric amplitudes at all levels on the operated side. In the digital pulse-curve recordings the greatest improvement was found in inclination time and RAMP25.

The influence of arm ischaemia and arm hyperaemia on subclavian and vertebral artery blood flow in patients with occlusive disease of the subclavian artery and the brachiocephalic trunk. A peroperative study.

A peroperative study of blood flow and flow direction was performed in series of patients with occlusive disease of the subclavian artery. Particular attention was focused on the flow variations caused by arm ischaemia and postischaemic hyperaemia and on the effect of injection of a vasodilator into the distal subclavian artery. The effect on blood flow and flow direction was measured with the aid of an electromagnetic flowmeter. During arm ischaemia induced by an inflated cuff on the arm, the subclavian flow diminished, as did the vertebral artery flow when it was retrograde. If the vertebral artery flow was anterograde, it increased during arm ischaemia. The postischaemic hyperaemia caused an increase of the subclavian flow and of reversed vertebral flow. If the vertebral flow was anterograde, it diminished during the postischaemic hyperaemia. Similar findings were obtained with intra-arterial injection of a vasodilator. The large amount of blood flow passing through the vertebral artery, as well as the flow variations caused by reactive arm hyperaemia, emphasize the role of this artery as a collateral vessel to the upper limb in cases of the subclavian steal phenomenon.