Injection rate: a factor in contrast reactions.
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Biomedical subjects
Publications and source records attributed to G G Hartnell.
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Balloon aortic valvoplasty is used in some patients with aortic valve stenosis who are unsuitable for aortic valve replacement. Complications associated with the retrograde approach can be avoided using an antegrade approach which has been less widely described. Experience of these two methods is reported and aspects of the differences in technique are emphasized. Aortic valvoplasty was attempted in 21 patients with severe aortic valve stenosis (mean gradient 65 mmHg). A significant reduction in gradient was achieved in 20 (mean reduction 59% transeptal group [four patients], 50% retrograde group [16 patients]) with symptomatic improvement in 18 patients which was maintained at follow-up (mean interval of 5.2 months, range 1-17 months) in 8/15 patients. There were only two significant, resolvable early complications and increases in aortic regurgitation were not seen. There were six late deaths but three patients improved sufficiently to undergo successful aortic valve replacement. Aortic valvoplasty provides good palliation of symptoms. In patients who are unsuitable for the retrograde approach the antegrade, transeptal approach is a satisfactory and effective alternative.
The chest radiographs of 600 consecutive patients undergoing insertion of a permanent cardiac pacemaker were reviewed to determine the incidence and nature of abnormalities present. Abnormalities were detected on the chest radiographs of 131 patients (21.8%). Unsatisfactory electrode tip position and other features related to the electrode wire were commonest (14.4%). Complications related to the lungs and pleura were present in 5.5%, and those related to the generator and pouch least frequent (1.9%). Complications occurred more frequently following installation of a replacement system (48.3%) compared to new systems (17.2%). Important complications not initially detected included pneumothorax (8/15) and poor electrode loop (26/27). Chest radiographs following permanent cardiac pacing frequently demonstrate significant abnormalities whose detection is improved by awareness of their incidence and nature.
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Conventional arteriography is the investigation of choice in patients with critical ischaemia to select the site for the distal anastomosis of a femorodistal bypass. Several arteriographic scoring systems have been devised in an attempt to quantify the run-off. More recently Pulse Generated Run-off and intraoperative peripheral resistance measurements have been proposed as better predictors of early graft patency. Eighty-eight consecutive femorodistal bypass grafts were studied using Pulse Generated Run-off (PGR), conventional and intra-arterial digital subtraction arteriography (DSA) and peripheral resistance measurement. Three widely used arteriographic scoring systems were used to grade the arteriographic run-off. There were significant correlations between the scoring systems and the measured peripheral resistance, although PGR correlated better with peripheral resistance than arteriography (rs = -0.59, P less than 0.001). Intra-arterial DSA improved the correlation between the arteriogram scoring systems and the measured peripheral resistance in the distal popliteal artery, but not in single calf vessels. In contrast, PGR correlated much better with peripheral resistance in single calf vessels (rs = -0.82, P less than 0.001). We recommend that selection for femorodistal reconstruction be based on a combination of intra-arterial DSA and PGR. PGR will identify patent distal calf vessels not seen on arteriography and determine their continuity with the pedal arch, two features which are essential prerequisites for successful femorodistal bypass.
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A retrospective review of patients with coronary angiography was undertaken to establish the incidence of ventricular fibrillation and other serious arrhythmias and to identify possible causative factors, in particular whether the use of non-ionic contrast medium increased the risk of a serious arrhythmia. Out of 3660 patients reviewed there were 10 cases of ventricular fibrillation. In all cases, there were identifiable technical factors thought to have accounted for the arrhythmia. There were no cases of ventricular fibrillation complicating a technically satisfactory injection of ionic or non-ionic contrast medium. There was no significant difference in the incidence of serious arrhythmias between patients given ionic and those given non-ionic contrast medium.
Twenty-eight pulmonary arteriovenous malformations in six patients were treated with coil embolization. The technique of embolization and the precautions taken to avoid complications are described. All patients had good relief of their symptoms and an improvement in arterial oxygenation. The observed complications were minor and our technique has now been modified to avoid these.
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Digital subtraction angiography (DSA) was used in the investigation, by dynamic cavernosography, of 35 men with acquired erectile impotence. The benefits of using DSA included shorter examination times, lower contrast medium dosage and better definition of abnormal veins. In particular deep crural veins are more clearly seen than in conventional studies and these may be of more importance than was previously thought.
Recent advances in the understanding of the causes of impotence have led to the recognition of various treatable physical causes. Some of these causes are related to vascular abnormalities which have necessitated the development of new imaging techniques. These now allow more precise diagnosis and the development of more appropriate surgical and radiological treatment.
Patients with pulmonary arteriovenous malformations (PAVMs) are at risk from a number of serious complications. The development of transcatheter embolization techniques now allows these patients to be effectively treated without the need for major open chest surgery.
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Conventional ultrasound is unreliable in detecting narrowing of the visceral arteries. Two cases are reported in which duplex Doppler ultrasound correctly identified severe narrowing of the celiac artery. Doppler ultrasound promises to be more accurate than conventional ultrasound in the diagnosis of visceral ischemia and may help to identify those patients who may require angiography.