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Biomedical subjects

A Rickards

Publications and source records attributed to A Rickards.

16 recordsLinked to original sources
PubMed1992

Angiographic restenosis after successful Wallstent stent implantation: an analysis of risk predictors.

Follow-up angiographic study was performed in 86 patients after initially successful Wallstent stent (Medinvent, Lausanne, Switzerland) implantation between April 1986 and October 1990. The stent angiographic restenosis rate was 16% at a mean of 8 months after stenting despite the inclusion of a substantial number of patients at high risk of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Of a total 15 variables analyzed, only suboptimal stent placement was found to be a significant predictor of stent restenosis. Age; gender; baseline New York Heart Association functional class; previous PTCA; indication for stenting; left ventricular ejection fraction; preangioplasty and immediate postangioplasty diameter stenosis severity; stented vessel site, lesional morphology; number, diameter, and length of stents implanted; and the interval between stenting and follow-up angiographic restudy were not significant risk factors of stent restenosis. Our study suggests that intracoronary stent implantation with the Wallstent may be a useful and promising adjunctive option after PTCA, particularly in patients at high risk of restenosis after PTCA. However, because of the significantly enhanced risk of restenosis after suboptimal stent implantation, we strongly recommend the selection and placement of Wallstent stents that adequately cover the entire length of the dilated coronary segment.

Adult↗
PubMed1989

Transvenous ablation of atrioventricular conduction with a low energy power source.

A power source modified to increase voltage delivery and minimise arcing (for a given energy) was used for transvenous ablation of atrioventricular conduction to control refractory supraventricular arrhythmias in 14 patients. Twelve had atrial fibrillation or flutter, one had atrioventricular nodal reentry tachycardia, and the other had permanent junctional reentry tachycardia. Despite treatment with 5-7 (median 6) antiarrhythmic drugs symptoms had persisted in all the patients. Cathodal discharges of 0.5-39.5 J were delivered to the distal electrode (in one case in parallel with the middle electrode). In all patients shocks produced complete atrioventricular block; this was permanent in eleven (79%). Four patients required a second procedure. In one patient, only a transient atrioventricular block could be produced and catheter ablation with a conventional power source also failed. In the other two atrioventricular conduction was modified such that previously ineffective treatment produced satisfactory control of heart rate. The cumulative energy delivered to those in whom permanent complete heart block resulted ranged from 3.6 to 97.8 (mean 38.3) J with a mean of three shocks (range 1-7) delivered per patient. During follow up of 1-28 (mean 14) months 11 patients remained in complete heart block and free of arrhythmia.

Aged↗
PubMed1988

Lack of effect of warfarin on the restenosis rate or on clinical outcome after balloon coronary angioplasty.

Between September 1985 and April 1987, 110 consecutive patients who had successful coronary angioplasty were included in a randomised prospective controlled evaluation of the effects of warfarin on restenosis. The warfarin (n = 56) and the control (n = 54) groups were not different in terms of age, sex, previous coronary bypass surgery or coronary balloon angioplasty, severity of symptoms, and frequency of multivessel disease or of total coronary occlusions. Warfarin was started on the day of the procedure and the dosage was adjusted to maintain the thromboplastin international normalised ratio greater than or equal to 2.5. One hundred and five (96%) of the patients were given verapamil and other antianginal drugs were prescribed as needed. Low molecular weight dextran and heparin were given during the procedure and heparin was continued for 24 hours in all patients. One hundred and eight (98%) of patients were followed up clinically after a median of five months (range 1-20). Eighty five (77%) had follow up angiography at five months. In the warfarin group symptoms improved in 46 (85%) patients by at least 1 angina class and 31 (57%) were symptom free; the exercise test remained positive in 20 (36%) patients and the angiographic restenosis rate was 25% per lesion and 29% per patient. There were no major bleeding complications. In the control group 46 (85%) patients were improved by at least 1 angina class and 31 (57%) were symptom free; the exercise test was positive in 11 (21%) patients and the angiographic restenosis rate was 33% per lesion and 37% per patient. Although the incidence of angiographic restenosis tended to be lower with warfarin, none of these differences was significant. These data suggest that the combination of verapamil and warfarin, in the absence of aspirin, is not significantly better than verapamil alone in preventing symptom recurrence or angiographic restenosis after coronary angioplasty.

Adult↗
PubMed1987

Outcome in infants of birth weight 500 to 999 g: a continuing regional study of 5-year-old survivors.

During 1979 and 1980, 351 infants of birth weight 500 to 999 g were born in the State of Victoria: 89 (25.4%) survived to the age of 2 years corrected for prematurity, and 83 were fully assessed by a multidisciplinary team; partial data were obtained on the remainder. At the age of 5 years, corrected for prematurity, 85/89 (96%) were evaluated by a multidisciplinary team, although not all children could be fully evaluated by the psychologists. Reports were available for another three children; one child was untraced. Of the survivors able to be classified at 5 years, 59/82 (72%) had no functional handicap. Functional handicaps was severe in 16 (19%), moderate in four (5%), and mild in three (4%). Functional handicaps were present in 50% (8/16) of outborn survivors compared with the 23% (15/66) for the inborn survivors (P = 0.02). Cerebral palsy was diagnosed in eight children at 5 years and in 12 children at 2 years. The diagnosis was stable for the children not ambulant at 2 years; five of seven 2-year-old children with mild cerebral palsy had "outgrown" the diagnosis by 5 years, but ataxic cerebral palsy was not identified in one child until 5 years. Six children were blind; four had severe sensorineural or mixed deafness, one more than at 2 years. Of 82 children assessed according to identical criteria for functional handicap at both 2 and 5 years, 52 (63%) remained in the same category at 5 years, three (4%) were judged to be more severely handicapped, and 27 (33%) were less severely handicapped. The 2-year evaluation of extremely low birth weight children often proved to be unduly pessimistic, for many showed improvement or recovery from functional handicaps and impairments by 5 years of age.

Australia↗
PubMed1987

Coronary balloon angioplasty for elderly patients with severe angina.

From February 1983 to December 1986, 65 angioplasty procedures were attempted in 51 patients aged 65 or more. All had angina refractory to medical treatment and 89% of procedures were performed in patients in Canadian Cardiovascular Society angina class III or IV. Sixty eight per cent of patients had multivessel disease. Angioplasty was attempted on a single vessel in 52 instances (80%) and on multiple vessels in 13 (20%). The initial success rate was 75% for stenosis and 44% for occlusion. No attempt was made to treat all visible lesions in every case. At least one major complication occurred in 6.2% of the procedures: Q wave infarction in 4.6%, emergency surgery in 4.6%, and death in 4.6%. After a median follow up of four months (range 1-31) 37% of the patients in whom the procedure was initially successful were asymptomatic and 76% were improved by at least one Canadian Cardiovascular Society angina class. Angiographic restenosis occurred in 28% of treated lesions and 39% of patients had at least one recurrent stenosis. Among the patients with an initially successful procedure, 11% needed surgical revascularisation during the follow up period compared with 50% of those with a failed angioplasty. Balloon coronary angioplasty can be an effective form of treatment for the relief of severe angina in elderly patients.

Aged↗
PubMed1986

Relationship of growth and psychoneurologic status of 2-year-old children of birthweight 500-999 g.

There were 257 liveborn infants of birthweight 500-999 g born in one tertiary centre in the 5 1/4 years commencing January 1977; 86 (33.5%) survived to 2 years of age, corrected for prematurity and 83/86 (96.5%) were fully assessed. The prevalence of cerebral palsy was 10/83 (12%) and 17/83 (20%) had a major impairment. The distribution of weights and heights for 2-year-old boys and girls was significantly lower than for the standard population, as was the head circumference distribution for boys; the distribution of the Mental Developmental Index (Bayley Scales) was not related to the head circumference or body weight at two years or to head-circumference/bodyweight or height ratios. At birth measurements of weight, length and head circumference were under the 3rd percentile for 13/86 (15%), 9/86 (10.5%) and 9/86 (10.5%) respectively. By 2 years of age, weight, length and head circumference were under the 3rd percentile in 23/83 (27.7%), 26/83 (31.3%) and 4/83 (4.8%) respectively. 12 children who were SGA at birth were fully assessed at 2 years; the group of 6, who continued with poor postnatal weight gains (under the 3rd percentile) had the highest rate of major impairment but included were the only extremely SGA twins and the only two major malformations in the study. We found no association of other health problems or unfavourable social factors with poor postnatal growth or impaired outcome.

Blindness↗
PubMed1979

Influence of preoperative left ventricular function on results of homograft replacement of the aortic valve for aortic stenosis.

The effect of preoperative left ventricular function on early and late prognosis was assessed in 103 patients with aortic stenosis who underwent left ventricular cineangiography before homograft replacement of the aortic valve. The patients were separated into two groups: Group A (58 patients) with an ejection fraction of 0.46 or more and Group B (45 patients) with an ejection fraction of 0.45 or less. The two groups were compared with respect to clinical and hemodynamic data as well as operative result. There was poor correlation between clinical data and left ventricular function. In Group A there were three early deaths (5.2 percent) and three late deaths (5.2 percent) compared with no early and six late deaths (13.3 percent) in Group B during the follow-up period of 12 to 102 months (mean 43 months). Most patients in Group B showed considerable symptomatic improvement but less than that observed in Group A. Forty-two patients (13 in Group A and 29 in Group B) underwent repeat cardiac catheterization and coronary angiography. Improvement in left ventricular function as assessed by radial analysis of segmental wall motion and ejection fraction was observed in 20 of the 29 patients in Group B. Failure of left ventricular function to improve was associated with additional coronary artery disease in the majority of patients. It is concluded that poor left ventricular function does not increase the risk of aortic valve replacement for aortic stenosis and that improvement in left ventricular function can be expected in the majority of patients.

Adolescent↗
PubMed1979

Influence of preoperative left ventricular function on results of homograft replacement of the aortic valve for aortic regurgitation.

The effect of preoperative left ventricular function on eraly and late prognosis was assessed in 69 patients with aortic regurgitation who underwent homograft replacement of the aortic valve. Patients were divided into two groups: Group A (38 patients) had an ejection fraction of 0.46 or more and Group B (31 patients) had an ejection fraction of 0.45 or less. Clinical data, hemodynamic data, and operative results were compared in the two groups. In Group A there was one early death (2.6%) and there were two late deaths (5.3%) compared to two early deaths (6.5%) and seven late deaths (22.6%) in Group B during a follow-up period of 13 to 98 months (mean, 49 months). Actuarial analysis showed a 94% survival at 6 years in Group A compared to 80% in Group B. Twenty-four patients were reinvestigated by repeat cardiac catheterization and coronary angiography at a mean time of 38 months following valve replacement. Left ventricular function was assessed by computerized quantitative radial analysis of segmental wall motion. Improvement in left ventricular function occurred in eight of the 14 patients reinvestigated in Group B, and appeared to be closely related to the etiology of the initial valve lesion. Despite the higher mortality rate in patients with poor left ventricular function, most derived considerable benefit from operation.

Adolescent↗
PubMed1977

The assessment of regional abnormalities of the left ventricle by angiography.

A method of regional wall motion analysis of left ventricular cineangiograms which does not make assumptions about ventricular geometry is described. The technique measures the movement of the ventricular perimeter in relation to the geometric center of gravity of the endsystolic frame expressing movement as a change in radical length. 10 control patinets each with 3 left ventricular cineangiograms, comprise the group for definition of normal values of movement and permit estimations of reproducibility within and across patient groups. Isolated examples of abnormal wall motion are shown.

Adult↗
PubMed1976

Transposition of the great arteries: logical anatomical arterial correction.

In a 20-month-old child with classic transposition of the great arteries the pulmonary artery, coronary arteries, and aorta were successfully retransposed at arterial level. It was difficult to reimplant the coronary arteries in the dilated pulmonary artery root without damaging the attachments of the valve cusps, and it may be better to divide the pulmonary artery first to avoid this hazard. Retransposition at arterial level will not be suitable for all patients with transposition of the great arteries, and many questions about long-term outcome remain to be answered.

Aorta, Thoracic↗
PubMed1976

Hemodynamic effects of verapamil and practolol in man.

The hemodynamic effects of verapamil and practolol were investigated in a group of 10 selected patients (7 with coronary artery disease) undergoing cardiac catherization. The drugs were given i.v. in a dose of 0.1 mg/kg, alone or in combination, before and after controling the heart rate by atrial pacing. Measured hemodynamic parameters included aortic and left ventricular pressure and its first derivative, cardiac output, and echocardiographically derived left ventricular dimensions. Each drug given individually caused minor hemodynamic changes, but the combination of practolol and verapamil when the heart rate was fixed by atrial pacing invaribly caused a reduction in LV dp/dt max which was independent of preload and afterload. It is concluded that both drugs have a mildly negative inotropic effect when administered at this dose intravenously to patients with normal or mildly impaired left ventricular function. The myocardial depression was more apparent when practolol preceded verpamil. Caution must be exercised when using these drugs in combination in patients with impaired myocardial function.

Adult↗