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Biomedical subjects

R Foale

Publications and source records attributed to R Foale.

At least 19 recordsLinked to original sources
PubMed2006

Dobutamine-induced hyperaemia inversely correlates with coronary artery stenosis severity and highlights dissociation between myocardial blood flow and oxygen consumption.

OBJECTIVES: To compare the relationship between dobutamine myocardial blood flow (MBF), rate-pressure product (RPP) and stenosis severity in patients with coronary artery disease (CAD). METHODS: 27 patients with single-vessel CAD were allocated to three groups based on stenosis severity: group 1, 50-69% (n = 9); group 2, 70-89% (n = 9); and group 3, >or= 90% (n = 9). Nine normal volunteers served as controls. Resting and dobutamine MBF were measured by positron emission tomography in the territory subtended by the stenosis (Isc) and remote myocardium (Rem). Mean left ventricular MBF was used for controls. RESULTS: In group 1, mean dobutamine MBF-Isc (2.48 (SD 0.48 ml/min/g)) and dobutamine MBF-Rem (2.70 (0.50) ml/min/g, NS) were comparable. In groups 2 and 3, dobutamine MBF-Isc (1.91 (0.44) and 1.22 (0.21) ml/min/g) was significantly lower than dobutamine MBF-Rem (2.27 (0.28) and 1.98 (0.25) ml/min/g, p < 0.02 and p < 0.005, respectively). An inverse relation between dobutamine MBF and stenosis severity existed both in Isc (r = 0.79, p < 0.001) and in Rem territories (r = 0.71, p < 0.001). For any given RPP, dobutamine MBF was greater in controls than in Rem (p < 0.05), which in turn was greater than in Isc (p < 0.05). CONCLUSION: Dobutamine MBF inversely correlated with stenosis severity and achieved significant flow heterogeneity for coronary stenoses > 70%. Dobutamine MBF and RPP were dissociated in both Isc and Rem segments in patients compared with controls.

Aged↗
PubMed2004

A multi-centre randomised controlled trial of minimally invasive direct coronary bypass grafting versus percutaneous transluminal coronary angioplasty with stenting for proximal stenosis of the left anterior descending coronary artery.

OBJECTIVES: To compare the clinical- and cost-effectiveness of minimally invasive direct coronary artery bypass grafting (MIDCAB) and percutaneous transluminal coronary angioplasty (PTCA) with or without stenting in patients with single-vessel disease of the left anterior descending coronary artery (LAD). DESIGN: Multi-centre randomised trial without blinding. The computer-generated sequence of randomised assignments was stratified by centre, allocated participants in blocks and was concealed using a centralised telephone facility. SETTING: Four tertiary cardiothoracic surgery centres in England. PARTICIPANTS: Patients with ischaemic heart disease with at least 50% proximal stenosis of the LAD, suitable for either PTCA or MIDCAB, and with no significant disease in another vessel. INTERVENTIONS: Patients randomised to PTCA had local anaesthetic and underwent PTCA according to the method preferred by the operator carrying out the procedure. Patients randomised to MIDCAB had general anaesthetic. The chest was opened through an 8-10-cm left anterior thoracotomy. The ribs were retracted and the left internal thoracic artery (LITA) harvested. The pericardium was opened in the line of the LAD to confirm the feasibility of operation. The distal LITA was anastomosed end-to-side to an arteriotomy in the LAD. All operators were experienced in carrying out MIDCAB. MAIN OUTCOME MEASURES: The primary outcome measure was survival free from cardiac-related events. Relevant events were death, myocardial infarction, repeat coronary revascularisation and recurrence of symptomatic angina or clinical signs of ischaemia during an exercise tolerance test at annual follow-up. Secondary outcome measures were complications, functional outcome, disease-specific and generic quality of life, health and social services resource use and their costs. RESULTS: A total of 12,828 consecutive patients undergoing an angiogram were logged at participating centres from November 1999 to December 2001. Of the 1091 patients with proximal stenosis of the LAD, 127 were eligible and consented to take part; 100 were randomised and the remaining 27 consented to follow-up. All randomised participants were included in an intention-to-treat analysis of survival free from cardiac-related events, which found a non-significant benefit from MIDCAB. Cumulative hazard rates at 12 months were estimated to be 7.1 and 9.2% for MIDCAB and PTCA, respectively. There were no important differences between MIDCAB and PTCA with respect to angina symptoms or disease-specific or generic quality of life. The total NHS procedure costs were 1648 British pounds and 946 British pounds for MIDCAB and PTCA, respectively. The costs of resources used during 1 year of follow-up were 1033 British pounds and 843 British pounds, respectively. CONCLUSIONS: The study found no evidence that MIDCAB was more effective than PTCA. The procedure costs of MIDCAB were observed to be considerably higher than those of PTCA. Given these findings, it is unlikely that MIDCAB represents a cost-effective use of resources in the reference population. Recent advances in cardiac surgery mean that surgeons now tend to carry out off-pump bypass grafting via a sternotomy instead of MIDCAB. At the same time, cardiologists are treating more patients with multi-vessel disease by PTCA. Future primary research should focus on this comparison. Other small trials of PTCA versus MIDCAB have now finished and a more conclusive answer to the original objective could be provided by a systematic review.

Aged↗
PubMed2002

Anal sac adenocarcinoma in a Siamese cat.

A 12-year-old male neutered Siamese cat presented with a history of inappetance and lethargy and an enlarged left anal sac. The anal sac was surgically excised and histopathology confirmed the diagnosis of anal sac adenocarcinoma. Perianal tumours are rare in the cat and anal sac adenocarcinoma has not been previously reported. This is in contrast to the dog where anal sac adenocarcinoma is a well recognised albeit uncommon tumour.

Adenocarcinoma↗
PubMed2001

Cardiac investigation and intervention prior to thoraco-abdominal aneurysm repair: coronary angiography in 35 patients.

OBJECTIVE: retrospective studies indicate a high risk of cardiac events in patients undergoing thoraco-abdominal aneurysm repair. We aimed to determine the prevalence of coronary disease in these patients, define the role of non-invasive cardiac testing and assess the short-term outcome of coronary re-vascularisation. DESIGN: a prospective cohort study of consecutive patients referred to a single surgeon. MATERIALS AND METHODS: forty patients recruited over 16 months (Type I, 6; II, 11; III, 8; IV, 15). Dobutamine stress echocardiography, coronary angiography and coronary re-vascularisation (PTCA or CABG) were performed according to a pragmatic protocol. Main outcome measures were the prevalence of coronary artery disease, sensitivity and specificity of clinical assessment and non-invasive cardiac testing, and adverse events associated with coronary investigation and intervention. RESULTS: seven patients (17.5%) were stratified as having high perioperative cardiac risk. The majority of patients (23, 57.5%) had no cardiac risk factor other than the operation type. Five patients (12.5%) had inducible ischaemia on non-invasive testing. Fourteen patients (40%) had haemodynamically significant coronary artery stenoses, of whom 12 (34%) underwent coronary revascularisation. Dobutamine stress echocardiography demonstrated 100% specificity and 71% sensitivity for the detection of significant coronary artery lesions. Coronary re-vascularisation by three-vessel bypass grafting was complicated by non-fatal stroke in one patient. Thirty-five patients (87.5%) proceeded to aneurysm repair. No patient who had been adequately investigated suffered a cardiac complication. CONCLUSIONS: the 40% prevalence of coronary artery disease in these patients is comparable to that of other patients undergoing arterial surgery. Non-invasive testing proved beneficial, both in screening low-risk patients and planning intervention in patients at higher risk. An aggressive approach to intervention was associated with an acceptable complication rate and favourable short-term outcome.

Adult↗
PubMed2000

Ethnic and gender differences in electrocardiographic QT length and QT dispersion in hypertensive subjects.

BACKGROUND: Prolonged QT intervals and/or increased QT dispersion (QTd) are associated with various pathological conditions and predict death in healthy individuals. Among hypertensives, QTd correlates with blood pressure (BP) and left ventricular mass index (LVMI) and QT intervals are prolonged in those with left ventricular hypertrophy (LVH). In normotensives, heart-rate corrected QT length (QTc) is longer in females than males, but QTd is greater in males than females. There are few data comparing QT parameters between different ethnic groups and none specifically in hypertensives. Among normotensives, compared with whites, QTc is reported to be shorter in African-Americans and longer in Chinese. We looked for ethnic and gender differences in QT parameters in hypertensive subjects. METHODS: Untreated hypertensives were selected from a Hypertension Clinic database. Black and white subjects were matched for age, sex, BP and LVMI. Male and female subjects were matched for age, race, BP and the presence or absence of echocardiographic LVH. Maximum QT intervals (QTm), rate-corrected maximum QT intervals (QTc) and QT dispersion (QTd) were measured or calculated from ECGs. Data are presented as mean +/- s.d. Differences in QT parameters were sought between groups using Student's t-tests. RESULTS: No ethnic or gender differences in QT parameters achieved statistical significance. However there was a tendency for QTm and QTc to be prolonged in blacks compared with whites (443 +/- 52 vs 421 +/- 47; P = 0.08 and 480 +/- 65 vs 463 +/- 40: P = 0.24 respectively), and for QTc to be prolonged in females compared with males (479 +/- 52 vs 461 +/- 45 ms; P= 0.13). CONCLUSION: In small groups of matched hypertensives, no ethnic or gender differences in QT parameters achieved statistical significance. However, similar to findings in normotensives, QTc tended to be longer in hypertensive females than males. In hypertensives, we failed to confirm the finding that QTc is shorter in blacks than whites, as seen in US normotensives. Whether this represents a difference between hypertensives and normotensives, or between US and UK blacks requires further investigation. Whether the prognostic significance of QT parameters in hypertensives differs between different gender and ethnic groups needs to be established from prospective studies. Journal of Human Hypertension (2000) 14, 403-405

Adult↗
PubMed2000

Limitation of coronary reserve after successful angioplasty is prevented by oral pretreatment with an alpha1-adrenergic antagonist.

Coronary vasoconstriction that occurs after percutaneous transluminal coronary angioplasty (PTCA) is abolished by intracoronary phentolamine. An impairment of coronary vasodilator reserve (CVR) has been observed < or = 7 days after successful PTCA. To ascertain whether pretreatment with the alpha1-adrenergic receptor blocker doxazosin could prevent the limitation of CVR after PTCA, we carried out a randomised, double-blind, controlled study on 26 patients with significant (> 75%) single vessel disease undergoing PTCA. Twelve patients received doxazosin 4 mg daily in addition to their standard treatment, while 14 patients received matching placebo, starting 11 days before PTCA. Myocardial blood flow (MBF) at baseline and after i.v. dipyridamole (0.56 mg/kg) was measured within 5 days after PTCA using positron emission tomography (PET) with oxygen-15-labelled water. Angioplasty was successful in all patients with a residual stenosis < or = 35%. At PET scanning, hemodynamic parameters were comparable in the two groups. In the territory subtended by the dilated artery, CVR was significantly higher in patients treated with doxazosin compared with those receiving placebo (2.78 +/- 0.1.21 vs. 1.95 +/- 0.68; p < 0.01). Conversely, CVR in the remote territories subtended by angiographically normal arteries was similar in the two groups (2.53 +/- 0.92 and 2.48 +/- 0.80, respectively; p = NS). Treatment with oral doxazosin in addition to standard antianginal therapy can prevent the impairment of CVR frequently observed despite successful PTCA.

Administration, Oral↗
PubMed2000

Persistent but reversible coronary microvascular dysfunction after bypass grafting.

The effect of coronary artery bypass grafting (CABG) on absolute myocardial blood flow (MBF) has not been investigated previously. MBF (ml. min(-1). g(-1)) was measured at rest and during hyperemia (0.56 mg/kg iv dipyridamole) using H(2)(15)O and positron emission tomography in eight patients with three-vessel disease before surgery and 1 and 6 mo after full revascularization. Baseline MBF was 0.87 +/- 0.12 preoperatively and 1.04 +/- 0.14 and 0.95 +/- 0.13 at 1 and 6 mo after CABG, respectively (P < 0.05, 6 mo vs. preoperatively). Hyperemic MBF was 1.36 +/- 0.28 preoperatively and increased to 1.98 +/- 0.50 and 2.45 +/- 0.64 at 1 and 6 mo after CABG, respectively (P < 0.01, 6 mo vs. preoperatively). Coronary vasodilator reserve (hyperemic/baseline MBF) increased from 1.59 +/- 0.40 preoperatively to 1.93 +/- 0.13 and 2.57 +/- 0.49 at 1 and 6 mo, respectively (P < 0.05, 6 mo vs. preoperatively). Minimal (dipyridamole) coronary resistance (mmHg. min. g(-1). ml(-1)) fell progressively from 59.37 +/- 14.56 before surgery to a nadir of 35. 76 +/- 10.12 at 6 mo after CABG (P < 0.01 vs. preoperatively). The results of the present study confirm that CABG improves coronary vasodilator reserve progressively as a result of reduction in minimal coronary resistance. These data suggest persistent microvascular dysfunction that recovers slowly after surgery.

Adult↗
PubMed2000

Effects of 7 years of growth hormone replacement therapy in hypopituitary adults.

Short-term studies of GH replacement in adult hypopituitarism have usually demonstrated beneficial effects on body composition and circulating lipids, with neutral or occasionally adverse effects on glucose tolerance. Fasting hyperinsulinemia has been reported. GH effects on cardiac function have been variable. The effects of long-term GH therapy, taking into account the consequences of increasing age, are not fully known. Thirty-three hypopituitary, initially middle-aged adults were studied over a 7-yr period; 12 patients took GH therapy (mean, 0.7 mg daily) continuously (group A); 11 took GH for only 6-18 months, a minimum of 5 yr previously (group B); and 10 patients never received GH therapy (group C). Other pituitary replacement was maintained. Effects on anthropometry, body composition (by bioimpedance analysis, total body potassium, and dual energy x-ray absorptiometry), circulating lipids, glucose and insulin concentrations, cardiac 2-dimensional and Doppler echocardiography, and exercise tolerance were assessed before and after the treatment period. Continuous GH therapy had no significant effect on body weight, but it prevented the increase in waist circumference and waist to hip ratio that occurred in the patients without GH substitution (waist to hip ratio, group A, 0.87+/-0.08 at baseline, 0.85+/-0.09 at 7 yr; group B, 0.89+/-0.11 at baseline, 0.94+/-0.11 at 7 yr; P < 0.005 for GH effect; group C, 0.87+/-0.10 at baseline, 0.92+/-0.10 at 7 yr; P < 0.005 for GH effect). A GH-induced decrease in subscapular skinfold thickness was also observed. By bioimpedance analysis, GH therapy caused an increase in total body water and fat-free mass, and a decrease in the percent body fat. Although changes occurred with time in all groups, no significant additional GH therapy effects were observed on glucose tolerance, insulin concentrations, lipid levels, cardiac dimensions, echocardiographic diastolic function, or exercise tolerance. In conclusion, prolonged GH substitution in middle-aged hypopituitary adults causes a sustained improvement in body composition. Other benefits, e.g. on lipid levels and exercise tolerance, were not apparent at 7 yr when comparisons were made with GH-untreated hypopituitary controls. Potentially adverse effects on glucose tolerance and insulinemia did not develop with prolonged GH therapy.

Absorptiometry, Photon↗
PubMed1998

Evidence of left ventricular dysfunction in children with merosin-deficient congenital muscular dystrophy.

BACKGROUND: Deficiency of the sarcolemmal protein dystrophin has been linked to dilated cardiomyopathy. Some children with congenital muscular dystrophy have a deficiency of the laminin alpha2 chain of merosin, an extracellular matrix protein linked to dystrophin through a group of glycoproteins. It has been shown that deficiency in one of these glycoproteins is responsible for muscular dystrophy and dilated cardiomyopathy. Children with laminin alpha2 deficiency may be at risk for development of cardiomyopathy. METHODS AND RESULTS: We studied the cardiac function of a cohort of 16 children with congenital muscular dystrophy by using 2-dimensional echocardiography. The expression of the laminin alpha2 of merosin in the patients was determined on a skin or muscle biopsy. Two of 6 merosin-deficient children had an ejection fraction <40%. The average ejection fraction of the merosin-deficient children was 43%+/-11%, which was significantly lower than the merosin-positive children (53%+/-5%, P=.03). CONCLUSIONS: This study suggests that a deficiency of laminin alpha2 can give rise to dilated cardiomyopathy, supporting the idea that defects of dystrophin, or of associated proteins, can cause dilated cardiomyopathy in addition to muscular dystrophy.

Adolescent↗
PubMed1997

Retrieval of detached coating of a hydrophilic guidewire from the profunda femoris artery using an Amplatz gooseneck snare.

We present a case where during accidental puncture of the profunda femoris artery the plastic coating of a hydrophilic guidewire was stripped off against the bevel of a metal needle. This lay coiled in the profunda femoris artery. It was retrieved using an Amplatz gooseneck snare from an ipsilateral antegrade common femoral artery puncture.

Catheterization, Peripheral↗
PubMed1997

Listeria endocarditis: current management and patient outcome--world literature review.

This is believed to be the 58th reported case of Listeria monocytogenes infective endocarditis. Published reports worldwide were reviewed as to treatment, outcome, and prognostic features. There is controversy over whether all patients with this condition should have surgery. Moreover the best antibiotic treatment is not known, which accounts for the heterogeneity of regimens used. Listeria endocarditis has a high mortality rate (37%). This was higher in men (41% v 32%) and in patients with valve prostheses (41% v 31%), though neither observation reached statistical significance. There was no significant difference in mortality between surgical and non-surgical treatment, but untreated listeria endocarditis proved universally fatal. From the data, treatment with ampicillin is recommended, with resort to surgery in cases where the infection cannot be eradicated or where haemodynamic compromise has occurred.

Aged↗
PubMed1995

Replacement treatment with biosynthetic human growth hormone in growth hormone-deficient hypopituitary adults.

OBJECTIVES: The physiological role of growth hormone in adult life has recently attracted increased interest. We have studied the clinical effects and the effects on body composition of prolonged replacement with biosynthetic human GH in a large number of hypopituitary adults. DESIGN: A randomized double blind placebo controlled trial for 6 months followed by an open trial of GH treatment for 12 months. GH daily dose was 0.04 (0.02-0.05) IU/kg s.c. PATIENTS: Forty GH deficient hypopituitary patients (19 M, 21 F; aged 19-67 years) on conventional replacement therapy were studied. MEASUREMENTS: Serum insulin like growth factor I (IGF-I), skinfold thickness, total body potassium, total body water (TBW), exercise tolerance and muscle strength, and well-being. RESULTS: During the 6-month double blind phase, two GH treated patients withdrew because of adverse events. Lean body mass (LBM) increased and percentage body fat (%BF) decreased on GH but not on placebo (P) (LBM: (GH: from 48.5 +/- 9.6 to 49.6 +/- 9.5 kg; P: from 50.9 +/- 9.2 to 50.1 +/- 9.0 kg, P < 0.05 GH vs P) and %BF (GH: from 34.7 +/- 11.4 to 34.2 +/- 10.7; P: from 37.4 +/- 7.6 to 38.7 +/- 8.1, P < 0.05 GH vs P)). TBW increased on GH (P < 0.01) but not on P. No change was observed in waist-to-hip ratio or in muscle strength. During longer-term follow-up combining the double blind and open phase components of the study, 34, 27 and 11 patients received GH for 6, 12 and 18 months respectively. Patients dropped out because of adverse events or lack of perceived benefit. Skinfold thicknesses decreased significantly at 6 and 12 months and the waist circumference at 6 months. Waist-to-hip ratio decreased significantly on GH at 12 months. LBM increased on GH treatment from 49.6 +/- 9.1 to 51.6 +/- 9.4 kg (P < 0.0006), 51.9 +/- 8.9 kg (P < 0.07) and 53.1 +/- 10.5 kg (P < 0.0001) at 6, 12 and 18 months respectively. Percentage body fat decreased on GH from 37.2 +/- 10.7 to 34.7 +/- 10.1 (P < 0.005), 35.1 +/- 12.8 (NS) and 34.5 +/- 8.6 (P < 0.04) at 6,12 and 18 months respectively. TBW also increased at 6 and 12 months of GH treatment. Exercise time increased significantly at 6, 12 and 18 months of GH treatment. Muscle strength in selected muscle groups increased significantly at 6, 12 or 18 months of GH treatment. Randomization resulted in the placebo group having a greater GHQ score (higher morbidity) than the GH group before therapy. Over the controlled phase, GHQ scores improved on placebo but not on GH and CPRS score was unchanged in either group. In the open phase, the GHQ score did not change on GH therapy but CPRS score improved at 6 and 12 months. CONCLUSIONS: Growth hormone replacement therapy in adults for 6 months increased lean body mass, total body water and exercise tolerance, and decreased body fat. Growth hormone replacement for longer than 6 months maintains the advantageous effects seen in shorter-term studies and may have additional effects on body fat distribution, muscle strength and psychological well-being.

Adult↗
PubMed1995

Cardiovascular effects of prolonged growth hormone replacement in adults.

OBJECTIVES: To study the cardiovascular effects of human growth hormone (GH) replacement therapy in adults. INTERVENTION: Biosynthetic human GH given in a daily dose of 0.04 +/- 0.01 IU kg-1 for 6-18 months in an open trial. PATIENTS: Thirty-four GH-deficient hypopituitary patients on conventional replacement therapy, aged 19-67 years and with a body mass index of 18.0-410.0 kg/m2. MEASUREMENTS: Resting blood pressure, exercise tolerance, renal function and routine blood counts were assessed every 6 months. Two-dimensional echocardiography and Doppler ultrasound scanning were performed at 0, 6 and 12 months of GH therapy. RESULTS: Exercise time increased significantly on GH from 9.37 +/- 2.64 min at the start to 10.39 +/- 2.86 min (P < 0.001), 10.90 +/- 2.48 min (P < 0.001) and 11.11 +/- 0.70 min (P < 0.001) at 6, 12 and 18 months respectively. There was no change in the heart rate or in the blood pressure at rest nor at the peak of exercise. No significant changes were observed in measures of cardiac structure (left ventricular mass index, left ventricular posterior wall thickness and interventricular septal thickness), ejection fraction nor in cardiac output. Isovolumic relaxation time, a marker of diastolic function, decreased in 24 patients after 6 months on GH (from 98.6 +/- 15.9 to 89.6 +/- 15.2 ms; P < 0.03) but it was not different from baseline in the 18 patients who were restudied at 12 months. There was no significant change in the left ventricular filling neither at 6 nor at 12 months. No significant, changes were observed in plasma electrolytes, creatinine nor in blood count on GH treatment. CONCLUSIONS: Growth hormone replacement therapy in hypopituitary adults for 6-18 months produced sustained increase in exercise tolerance but was not associated with changes in cardiac structure or systolic function.

Adult↗