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Biomedical subjects

Shakeel A Qureshi

Publications and source records attributed to Shakeel A Qureshi.

13 recordsLinked to original sources

Coronary arterial fistulas.

A coronary arterial fistula is a connection between one or more of the coronary arteries and a cardiac chamber or great vessel. This is a rare defect and usually occurs in isolation. Its exact incidence is unknown. The majority of these fistulas are congenital in origin although they may occasionally be detected after cardiac surgery. They do not usually cause symptoms or complications in the first two decades, especially when small. After this age, the frequency of both symptoms and complications increases. Complications include 'steal' from the adjacent myocardium, thrombosis and embolism, cardiac failure, atrial fibrillation, rupture, endocarditis/endarteritis and arrhythmias. Thrombosis within the fistula is rare but may cause acute myocardial infarction, paroxysmal atrial fibrillation and ventricular arrhythmias. Spontaneous rupture of the aneurysmal fistula causing haemopericardium has also been reported. The main differential diagnosis is patent arterial duct, although other congenital arteriovenous shunts need to be excluded. Whilst two-dimensional echocardiography helps to differentiate between the different shunts, coronary angiography is the main diagnostic tool for the delineation of the anatomy. Surgery was the traditional method of treatment but nowadays catheter closure is recommended using a variety of closure devices, such as coils, or other devices. With the catheter technique, the results are excellent with infrequent complications.

Arterio-Arterial Fistula↗

Covered Cheatham-platinum stents for aortic coarctation: early and intermediate-term results.

OBJECTIVES: This study sought to evaluate the use of covered Cheatham-platinum (CP) stents in the treatment of aortic coarctation (CoA). BACKGROUND: Aortic aneurysms and stent fractures have been encountered after surgical and transcatheter treatment for CoA. Covered stents have previously been used in the treatment of abdominal and thoracic aneurysms in adults. We implanted covered CP stents as a rescue treatment in patients with CoA aneurysms or previous stent-related complications and in patients at risk of developing complications because of complex CoA anatomy or advanced age. METHODS: Thirty-three covered CP stents were implanted in 30 patients; 16 patients had had previous procedures. The remaining patients had complex or near-atretic CoA. RESULTS: The mean patient age and weight were 28 (+/-17.5) years (range 8 to 65 years), and 62 (+/-13) kg (range 28 to 86 kg), respectively. The systolic gradient across the CoA decreased from a mean (+/-SD) of 36 +/- 20 mm Hg before to a mean of 4 +/- 4 mm Hg after the procedure (p < 0.0001), and the diameter of the CoA increased from 6.4 +/- 3.8 mm to 17.1 +/- 3.1 mm (p < 0.0001). The follow-up period was up to 40 months (mean, 11 months). All stents were patent and in good position on computed tomography or magnetic resonance imaging performed three to six months later. In 43% of the patients antihypertensive medication was either decreased or stopped. CONCLUSIONS: Covered CP stents may be used as the therapy of choice in patients with complications after CoA repairs, whereas they provide a safe alternative to conventional stenting in patients with severe and complex CoA lesions or advanced age.

Adolescent↗

Catheterization in neonates with pulmonary atresia with intact ventricular septum.

Cardiac catheterization is infrequently required in babies with pulmonary atresia with intact ventricular septum. The main indications are to decide on the best form of treatment, the options being determined by the right ventricular as well as infundibular morphology and the presence of right-ventricle dependent coronary circulation. In most cases, an interventional approach is appropriate. This can consist of radiofrequency or laser perforation of the atretic pulmonary valve, combined with balloon dilation. In some patients, additional stenting of the arterial duct may be needed.

Cardiac Catheterization↗

A system for real-time XMR guided cardiovascular intervention.

The hybrid magnetic resonance (MR)/X-ray suite (XMR) is a recently introduced imaging solution that provides new possibilities for guidance of cardiovascular catheterization procedures. We have previously described and validated a technique based on optical tracking to register MR and X-ray images obtained from the sliding table XMR configuration. The aim of our recent work was to extend our technique by providing an improved calibration stage, real-time guidance during cardiovascular catheterization procedures, and further off-line analysis for mapping cardiac electrical data to patient anatomy. Specially designed optical trackers and a dedicated calibration object have resulted in a single calibration step that can be efficiently checked and updated before each procedure. An X-ray distortion model has been implemented that allows for distortion correction for arbitrary c-arm orientations. During procedures, the guidance system provides a real-time combined MR/X-ray image display consisting of live X-ray images with registered recently acquired MR derived anatomy. It is also possible to reconstruct the location of catheters seen during X-ray imaging in the MR derived patient anatomy. We have applied our registration technique to 13 cardiovascular catheterization procedures. Our system has been used for the real-time guidance of ten radiofrequency ablations and one aortic stent implantation. We demonstrate the real-time guidance using two exemplar cases. In a further two cases we show how off-line analysis of registered image data, acquired during electrophysiology study procedures, has been used to map cardiac electrical measurements to patient anatomy for two different types of mapping catheters. The cardiologists that have used the guidance system suggest that real-time XMR guidance could have substantial value in difficult interventional and electrophysiological procedures, potentially reducing procedure time and delivered radiation dose. Also, the ability to map measured electrical data to patient specific anatomy provides improved visualization and a path to investigation of cardiac electromechanical models.

Cardiac Catheterization↗

Use of covered Cheatham-Platinum stents in aortic coarctation and recoarctation.

We inserted covered Cheatham-Platinum stents in 4 patients, ranging in age from 12 to 19 years, who weighed between 45 and 94 kg. All the patients had aortic coarctation, with surgical repair having been attempted previously in one, and with balloon dilation having been performed as the primary treatment in two, resulting in formation of aneurysms. The fourth patient had not received any treatment. The gradients were reduced from 10 to 40 mmHg before insertion of the stent to 0 to 5 mmHg after stenting. No complications were encountered. All the patients are well at an interval of 3 to 14 months after stenting.

Adolescent↗

Proposals for future training in interventional paediatric cardiology.

Training in all medical disciplines is currently undergoing a major overhaul. There is a move away from the old concept of training as an apprentice, towards more structured programmes of training. Proposals have recently been made to shorten higher specialist training to 3-4 years, thus producing "generalist" consultants to meet the growing need for service. Advanced subspeciality training can then be undertaken by those with the ability, and desire, to do so following the core training. In the near future, therefore, subspeciality training will need to meet the needs of those undertaking core training, and those wishing to develop a higher degree of expertise. It will have to be focused, to allow skills appropriate to the future practice to be undertaken as a consultant to be developed efficiently. We propose a new scheme for training in interventional paediatric cardiology as a template for subspeciality training. The scheme proposes training at three levels. The first level, basic training, is required of all trainees. Training for the intermediate level will be required for those proposing to carry out diagnostic cardiac catheterisation and basic intervention. Training at the advanced level will be needed by those who wish to carry out a wide range of interventional procedures. A curriculum is proposed for each level, detailing skills that must be attained. Attendance at procedures needs to be driven by the educational needs of the trainee, rather than the requirements of the service. Objective methods are suggested to allow assessment of competence. These should supersede log-books, which document only procedural numbers. Training may be needed for the trainers to ensure that teaching and assessment achieve agreed standards of excellence.

Cardiac Catheterization↗

Simultaneous treatment of native coarctation of the aorta combined with patent ductus arteriosus using a covered stent.

A 19-year-old girl with coarctation of the aorta and patent ductus arteriosus underwent simultaneous treatment of native coarctation and closure of ductus arteriosus using a covered Cheatham-Platinum stent. This technique may be used as an alternative to other forms of interventional therapy or surgery for this combination of lesions in adolescents and adults.

Abnormalities, Multiple↗

Neonatal transcatheter occlusion of a large coronary artery fistula with Amplatzer duct occluder.

A large fistula from the right coronary artery to the right atrium was diagnosed in a fetus at 22 weeks of gestation. Following delivery, the baby developed cardiac failure. The fistula was occluded at 3 weeks of age by transcatheter implantation of an Amplatzer duct occluder. Large coronary fistulas can be closed safely with a device even at this early age. Vigilance for ischemic events is required following implantation because of the rare possibility of thrombus extension proximally into the native coronary artery or spasm of the coronary artery.

Adult↗

Percutaneous insertion of the pulmonary valve.

OBJECTIVES: We report our experience of percutaneous valve insertion in pulmonary position in humans. BACKGROUND: Over the past 40 years, prosthetic conduits have been developed to surgically establish continuity between the right ventricle and the pulmonary artery. However, stenosis and insufficiency of the conduit due to valvular degeneration or panus ingrowth frequently occur, limiting patients' lifespan. Percutaneous stenting of conduits has recently emerged as a technique for delaying surgical replacement, but it creates a pulmonary regurgitation when crossing the valve. METHODS: Seven children and one adult with stenosis and/or insufficiency of the pulmonary graft underwent percutaneous implantation of a bovine jugular valve in pulmonary position. RESULTS: Percutaneous pulmonary valve (PV) replacement was successful in all patients. No complications occurred in early follow-up. Angiography, hemodynamic studies and echocardiography after the procedure showed no significant regurgitation of the implanted valve. Implantation was effective in relieving the obstruction in five patients. All patients showed improvement in their clinical status at the latest follow-up (mean 10.1 months). CONCLUSIONS: Non-surgical insertion of the PV is possible without any major complications. This new technique may have an important role in the management of conduit obstructions and pulmonary regurgitation.

Adolescent↗