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Biomedical subjects

I Hutton

Publications and source records attributed to I Hutton.

At least 37 records · Page 2Linked to original sources
PubMed1988

Thrombin and plasmin activity in coronary artery disease.

Basal plasmin and thrombin activity in plasma were assessed by radioimmunoassay of the fibrinogen derivatives containing the sequence B beta 15-42 and of fibrinopeptide A respectively in a cross sectional controlled study of men with coronary artery disease. Compared with healthy controls (n = 33) men with angiographically defined coronary artery disease (n = 98) had a modest but significant increase in concentrations of fibrinopeptide A, indicating an activated coagulation system. Concentrations of B beta 15-42 were similar in those with coronary artery disease and in the controls. The enhanced thrombin activity in coronary artery disease is in keeping with current evidence suggesting an association between coronary artery disease and a hypercoagulable state.

Adult↗
PubMed1987

The detection of coronary artery disease: a comparison of exercise thallium imaging and exercise equilibrium radionuclide ventriculography.

This study compared the accuracy of rest and exercise gated equilibrium technetium ventriculography with exercise thallium imaging in 50 consecutive male patients undergoing routine coronary angiography for the evaluation of chest pain. No patients were excluded on the basis of prior myocardial infarction, nature of angiographically defined coronary disease or symptoms. Antianginal therapy was continued in all patients. Eight patients had normal coronary arteries, 9 had single vessel, disease, 20 had double vessel disease and 13 had triple vessel disease. Sixteen patients had previously documented myocardial infarction. Using exercise radionuclide ventriculography, 34 patients with coronary disease were detected resulting in a sensitivity of 81%; 6 patients with normal coronary arteries had normal scans, a specificity of 75%, with a predictive accuracy of 80%. In comparison, thallium imaging detected 42 patients with coronary disease resulting in a sensitivity of 100%. Six patients with normal coronary arteries had normal thallium images resulting in a specificity of 75% and a predictive accuracy of 96%. These results suggest that exercise thallium imaging is a more accurate investigation than exercise equilibrium radio-nuclide ventriculography and is the investigation of choice in the noninvasive detection of coronary artery disease.

Adult↗
PubMed1987

Failure of gallium-67 citrate imaging to diagnose post-myocardial infarction (Dressler's) syndrome.

Gallium-67 scanning has been suggested as a means of diagnosing post-pericardiotomy syndrome. We have assessed the value of thoracic gallium scanning in patients with the post-myocardial infarction (Dressler's) syndrome, which is thought to have a similar pathogenesis. In five patients in whom the diagnosis was established by currently available means, 67Ga scans performed during active pericarditis showed no significant uptake in any case. No subject was receiving steroids but all were taking non-steroid anti-inflammatory drugs at the time of scanning. It is not clear why there should be differences in gallium uptake between the two conditions, but we conclude that 67Ga thoracic scanning is of no value in the management of patients with Dressler's syndrome.

Diagnosis, Differential↗
PubMed1987

Gated thallium scintigraphy in patients with coronary artery disease: an improved planar imaging technique.

The use of thallium scanning in the assessment of myocardial perfusion is well established. However, myocardial contraction leads to significant blurring of standard static images. By using electrocardiographic gating and a high sensitivity collimator, multiple view gated scans can be acquired prior to thallium redistribution. Reporting of these images on cine loop display in 100 consecutive patients undergoing coronary arteriography and 14 volunteers results in improved visual assessment of regional myocardial perfusion (with reduced interobserver variability) and, in addition, yields useful and accurate information on left ventricular function. The combination of better assessment of perfusion and information on wall motion results in improved detection of patients with significant coronary disease with no loss of specificity when compared with static images. Predictive accuracy improves from 85% to 94% with gated imaging. Gated thallium scanning could be readily applied in most centres using thallium at no extra cost and with improved predictive accuracy in the non-invasive detection of significant coronary disease.

Coronary Disease↗
PubMed1987

A comparison of intravenous elantan and frusemide in patients with chronic cardiac failure.

Opiates and loop diuretics are the mainstay of treatment of acute pulmonary oedema, but it is now recognized that immediate response to intravenous loop diuretics is acute vasoconstriction with impaired cardiac performance. It therefore seemed appropriate to compare the effects of intravenous isosorbide 5-mononitrate and frusemide on systemic and coronary haemodynamics in a group of patients with chronic cardiac failure at cardiac catheterization. Intra-arterial blood pressure was recorded from the ascending aorta, pulmonary capillary wedge pressure and cardiac output were measured using a Swan-Ganz thermodilution catheter. Coronary venous blood flow was measured using a thermodilution technique and A-V oxygen difference across the myocardium was obtained from simultaneous blood sampling in the aorta and coronary sinus. Absolute myocardial nutrient blood flow was measured using a 133Xe clearance technique. Frusemide in a dosage of 0.5 mg/kg given intravenously provoked acute vasoconstriction with falls in cardiac output and stroke volume. Pulmonary capillary wedge pressure was unchanged in the first 60 min after administration of frusemide. Isosorbide 5-mononitrate in a dosage of 15 mg intravenously, significantly reduced the pulmonary capillary wedge pressure within 5 min, and with the subsequent fall in systolic arterial blood pressure, cardiac output was maintained. These results suggest that intravenous isosorbide 5-mononitrate could well be of value in the immediate management of the patient with acute pulmonary oedema.

Blood Pressure↗
PubMed1987

Calcium channel blocker and isosorbide 5-mononitrate in the management of chronic cardiac failure.

In the management of the patient with chronic cardiac failure, the combination of an arteriolar vasodilator and venodilator should be beneficial. 8 patients with NYHA grade III-IV chronic cardiac failure were studied following placebo, after 4 weeks' therapy with the arteriolar vasodilator felodipine, and with the combination of felodipine and oral isosorbide 5-mononitrate. Haemodynamic measurements were made at rest and during dynamic exercise at an individual, fixed, near maximal workload. Ejection fraction (EF) was obtained by gated radionuclide ventriculography. At rest, heart rate was unchanged 73 +/- 6 at control, 72 +/- 4 with felodipine and 74 +/- 4 beats/min with the addition of isosorbide 5-mononitrate. Mean arterial pressure fell from 98 +/- 5 to 84 +/- 4 (p less than 0.02) and 84 +/- 3 mm Hg (p less than 0.02) with nitrate. Cardiac index increased from 2.2 +/- 0.1 to 2.5 +/- 0.2 litres/min/m2 with felodipine and further to 2.6 +/- 0.2 litres/min/m2 (p less than 0.02) with nitrate. Exercise tachycardia and mean arterial pressure were not significantly affected by therapy. Cardiac index increased on exercise from 4.4 +/- 0.3 to 4.8 +/- 0.3 litres/min/m2 with felodipine and 4.9 +/- 0.3 litres/min/m2 (p less than 0.05) with the addition of nitrate. Stroke volume index increased from 35.4 +/- 4 to 40.8 +/- 4 beats/min/m2 and further to 41.0 +/- 4 beats/min/m2 (p less than 0.05) and EF from 14 +/- 3 to 18 +/- 3% with nitrate. In conclusion, in patients with chronic cardiac failure, treatment with a calcium channel blocker produced sustained haemodynamic improvement, particularly on exercise, and combination with nitrate produced further benefit.

Chronic Disease↗
PubMed1987

Severity of coronary artery disease and basal fibrinolysis.

Basal venous blood levels of several components of the fibrinolytic enzyme system (plasminogen activator, plasminogen, fibrin degradation products, alpha 2-antiplasmin, and alpha 2-macroglobulin) were measured in 100 white men with angiographically defined coronary artery disease. The tests of fibrinolysis were not related to the severity of coronary artery disease, as indicated either by the number of vessels involved or by a coronary score system. Fibrinogen levels, however, did show a modest association with the extent of coronary atheroma (r = 0.21, p less than 0.05). Triglyceride levels were associated with the inhibitors of fibrinolysis: positively with alpha 2-antiplasmin (r = 0.31, p less than 0.005) and negatively with alpha 2-macroglobulin (r = -0.25, p less than 0.05). The alpha 2-antiplasmin levels were significantly elevated in patients with hypertriglyceridaemia. Neither smoking nor beta-blockade had any effect on the tests of fibrinolysis. This study adds support to the association of plasma fibrinogen with ischaemic heart disease.

Adult↗
PubMed1987

Transpulmonary angiotensin II formation in patients with chronic stable cor pulmonale.

The activity of the renin-angiotensin (RA) system and the ability of the lungs to generate angiotensin II (AII) were studied in 11 patients with stable cor pulmonale and respiratory failure caused by chronic obstructive bronchitis and emphysema. Angiotensin I concentrations (18.7 +/- 8.3 pmol/L) were normal, and transpulmonary AII formation rates (TRAIIFR) (14.2 +/- 18.1 pmol/min) were not significantly different from those recorded in nonedematous cardiac subjects (19.9 +/- 20.1 pmol/min), matched for sex, age, and diuretic therapy. The main determinant of TPAIIFR was the mixed venous AI concentration. Administration of oxygen for 30 min led to a small increase in TPAIIFR in the majority of patients. This increase could not be accounted for by changes in mixed venous AI. There was no correlation between serum angiotensin-converting enzyme levels and either the TPAIIFR or the systemic arterial AII concentrations.

Aged↗
PubMed1987

Ultrafiltration in diuretic-resistant cardiac failure.

Ultrafiltration was performed in 13 patients with diuretic-resistant cardiac failure. All patients had severely distressing peripheral edema and ultrafiltration was successfully completed in 12 patients, all of whom sustained symptomatic improvement. The volume of fluid removed ranged from 3.7 to 23 L, mean 11.8 L. Weight reduction produced by ultrafiltration continued over the following week, indicating an improved response to diuretic therapy. Ultrafiltration is an effective therapeutic intervention in the management of a small but well-defined group of patients with diuretic-resistant cardiac failure.

Aged↗
PubMed1986

Comparison of Doppler ultrasound velocity measurements with pressure differences across bioprosthetic valves in a pulsatile flow model.

Continuous wave Doppler ultrasound was used in vitro to assess the pressure differences across four different cardiac bioprosthetic valves in a pulsatile flow test apparatus. Valves were tested under four different flow conditions. Pressure differences were calculated from the maximum flow velocity measured by Doppler ultrasound and correlated well with the pressure differences measured directly in the flow model (r = 0.98). Thus Doppler ultrasound can accurately measure pressure differences across bioprosthetic valves in vitro.

Bioprosthesis↗
PubMed1986

Felodipine in ventricular dysfunction.

The systemic and coronary haemodynamic effects of felodipine were evaluated at rest and during stress induced atrial pacing in fourteen patients with chronic cardiac failure, secondary to coronary heart disease. Felodipine was an effective arteriolar vasodilator producing increases in cardiac index from 2.6 +/- 0.1 to 3.5 +/- 0.2 l min-1 m-2 (P less than 0.001) and stroke volume 35.3 +/- 2.7 to 41.4 +/- 2.4 ml beat-1 m-2 (P less than 0.002). Coronary venous flow also increased significantly (126 +/- 8 to 168 +/- 13 ml min-1) (P less than 0.005) and this did not appear to be accompanied by an increase in myocardial oxygen usage, as myocardial oxygen consumption was essentially unchanged. When the myocardium was stressed by atrial pacing the increase in cardiac output and stroke volume was maintained--25% and 23%, respectively (P less than 0.01). These results suggest that felodipine may well have a significant role in the management of patients with congestive cardiac failure.

Adult↗
PubMed1986

Ultrafiltration in the management of refractory congestive heart failure.

Ultrafiltration was performed in nine patients with congestive cardiac failure that was refractory to conventional medical treatment. A mean of 12 X 7 litres of fluid was removed, and there was a sustained symptomatic improvement in all patients. Weight loss continued after ultrafiltration and a sustained increase in serum sodium concentration was also noted. A transient fall in right atrial pressure was seen only at four hours after ultrafiltration. No adverse haemodynamic effects were seen four and eighteen hours after fluid removal. Intracardiac dimensions measured by echocardiography remained unchanged. Ultrafiltration can be used to relieve symptoms in patients with refractory congestive heart failure and gross oedema.

Blood Pressure↗
PubMed1986

Non-invasive assessment by Doppler ultrasound of 155 patients with bioprosthetic valves: a comparison of the Wessex porcine, low profile Ionescu-Shiley, and Hancock pericardial bioprostheses.

One hundred and fifty five patients with 167 bioprosthetic valves (68 Wessex porcine, 54 Hancock pericardial, and 45 low profile Ionescu-Shiley pericardial valves) were studied by Doppler ultrasound. Valve gradients were calculated from the mitral and aortic flow velocities by the modified Bernoulli equation. Mean mitral gradients were significantly smaller across the Ionescu-Shiley valves than across the Wessex porcine or Hancock pericardial valves. Mitral pressure half time was, however, significantly longer in the Hancock pericardial than in the Wessex porcine or Ionescu-Shiley valves. No significant differences were seen among the groups of aortic bioprostheses, though the comparable size of Wessex porcine valves showed significantly higher gradients. Bioprosthetic regurgitation was detected in 13 of 103 mitral and 11 of 59 aortic valves, though it was suspected clinically in only 12 mitral and six aortic bioprostheses. Doppler ultrasound is a repeatable non-invasive method of acquiring haemodynamic information in vivo from a variety of bioprostheses and it can detect bioprosthetic regurgitation at an early stage.

Adult↗
PubMed1986

Bedside hemodynamic monitoring in the management of acute cardiac patients.

Hemodynamic monitoring was performed in 100 acutely ill patients admitted to a Coronary Care Unit, 72 of whom had sustained an acute myocardial infarction (AMI). In patients with AMI, the initial pulmonary capillary wedge (PCW) pressure was related to prognosis, with a mortality of 68% in those with elevated pressures. The mean PCW pressure was 25 mmHg in those who died as compared with 17 mmHg (p less than 0.01) in the survivors. Cardiac catheterization confirmed the clinical impression of high risk in the majority of cases but also identified those in whom the clinical signs were misleading; 9 of those with AMI (12.5%) had high PCW pressures in the absence of clinical or radiological heart failure. The diagnosis of serious hemodynamic complications of AMI (right ventricular infarction, ventricular septal defect, and mitral regurgitation) was established in 14 cases (19%). There were no serious complications related to catheterization, and we conclude that pulmonary artery catheterization is safe and of clinical value in acutely ill cardiac patients.

Adult↗
PubMed1986

An unusual presentation of variant angina.

A previously well 46-year-old man presented with ventricular fibrillation as an initial complication of Prinzmetals variant angina. Coronary angiography subsequently demonstrated normal coronary arteries.

Angina Pectoris, Variant↗