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Biomedical subjects

R Balcon

Publications and source records attributed to R Balcon.

At least 37 records · Page 2Linked to original sources
PubMed1989

Phase and amplitude analysis of exercise digital left ventriculograms in patients with coronary disease.

Phase and amplitude analysis was applied to intravenous digital left ventriculograms to avoid the artefacts associated with image subtraction. Eight controls and 40 patients with known coronary artery disease underwent digital left ventriculography before and after a symptom limited supine bicycle exercise test. The resultant images were subjected to phase and amplitude analyses. In the control group there was no deterioration in left ventricular wall motion after exercise. In 30 of the 40 patients there was a deterioration in wall motion on exercise. This group contained all eight patients with three vessel disease and 12 of the 17 patients with two vessel disease. Ten patients showed no change in wall motion--five with one vessel disease and five with two vessel disease. Phase and amplitude analysis of digital left ventriculograms is a method of detecting exercise induced myocardial ischaemia that may help in the assessment of patients with coronary artery disease.

Coronary Disease↗
PubMed1989

Protective effect of collateral vessels during coronary angioplasty.

To assess the potential protective role of collateral vessels 27 patients undergoing angioplasty of the left anterior descending coronary artery were studied by intravenous digital subtraction left ventriculography. Fifteen patients had no collateral vessels (group 1) and 12 had some degree of collateral supply (group 2). During balloon inflation ST segment elevation in group 1 (4.9 mm) was significantly greater than that in group 2 (0.9 mm). Similarly the reduction in left ventricular ejection fraction was significantly greater in group 1 (24%) than in group 2 (12%). Both the size of ST segment elevation and the fall in ejection fraction correlated inversely with the extent of the collateral supply (r = -0.680 and r = -0.446 respectively). During balloon occlusion of the anterior descending coronary artery the percentage shortening of the anterior and apical segments fell in both groups but apical shortening fell to a lesser extent in group 2. An additional reduction in anterobasal contraction was confined to group 1. Electrocardiographic and ventriculographic manifestations of ischaemia produced by balloon inflation during angioplasty are less pronounced when collateral vessels are present. This suggests that the collateral circulation can protect myocardium at risk of ischaemia after coronary occlusion.

Angina Pectoris↗
PubMed1989

Patterns of coronary artery disease in post-infarction ventricular septal rupture.

Cardiac angiography was reviewed in 91 patients with post-infarction ventricular septal rupture. The results were compared with those of 123 stable survivors who had a positive submaximal exercise test early after infarction. Anterior infarction and occlusion of the infarct vessel were more common in those with ventricular septal rupture than in the comparison group. In the group with ventricular septal rupture there was more left ventricular damage, with aneurysm formation in two thirds, and coronary angiography showed more single than triple vessel disease. In the comparison group there was more triple vessel disease than single vessel disease. Angiographically demonstrable collaterals to the infarct territory were not seen or only very faintly seen in 82% of those with septal rupture. Well developed collaterals were seen in two thirds of the comparison group. These patterns of coronary disease suggest that ventricular septal rupture is more likely in patients with coronary occlusion and little or no collateral support to the infarct territory.

Collateral Circulation↗
PubMed1988

Assessment of left ventricular performance during percutaneous transluminal coronary angioplasty: a study by intravenous digital subtraction ventriculography.

Left ventricular performance during percutaneous transluminal coronary angioplasty was assessed in 52 patients by intravenous digital subtraction ventriculography. After injection of contrast into the right atrium ventriculograms were obtained before and during balloon inflation. In 37 patients they were also obtained after the procedure. A 12 lead electrocardiogram was monitored throughout. During balloon inflation the left ventricular ejection fraction fell (from 73% to 57%) in all but one patient; the decreases in patients with single vessel or multivessel disease were similar. The fall in left ventricular ejection fraction during percutaneous transluminal coronary angioplasty of the left anterior descending artery (19%) was significantly greater than that during balloon inflation in the right coronary (10%) or circumflex (8%) coronary arteries. It also reduced anterobasal, anterior, and apical segmental shortening while right coronary percutaneous transluminal coronary angioplasty affected inferior and apical segments. In 33 (63%) patients the ST segment was altered during balloon inflation. The fall in left ventricular ejection fraction correlated significantly with the magnitude of both ST segment elevation (r = 0.637) and ST depression (r = 0.396). Left ventricular ejection fraction and regional wall motion returned to baseline values after the procedure. Balloon inflation during percutaneous transluminal coronary angioplasty produces considerable abnormalities of global and regional left ventricular performance and this indicates the presence of myocardial ischaemia, which may not be apparent on electrocardiographic monitoring. Intravenous digital subtraction ventriculography is useful for monitoring left ventricular performance during controlled episodes of coronary occlusion produced by balloon inflation.

Adult↗
PubMed1988

Long term clinical outcome of coronary surgery and assessment of the benefit obtained with postoperative aspirin and dipyridamole.

Three hundred and twenty patients originally entered into a randomised study to assess the effect of aspirin and dipyridamole on the patency of coronary bypass grafts one year after operation were clinically reassessed a mean of 6.6 years (range 4.3-8.6) after operation. Patients were recruited between 1978 and 1982 after the present policy of total revascularisation had been adopted. During the follow up period there were 25 deaths of which 17 were due to cardiac causes (average annual cardiac mortality 0.8%). Of 280 patients available for contact, 250 (89.3%) attended an outpatient interview. Ninety four (37.6%) patients complained of recurrent angina but in only 23 (9.2%) was this severe. Two hundred and eleven (84.4%) of the 250 patients underwent exercise stress testing. There were 73 (34.6%) abnormal tests of which 52 were in the group of 94 patients with recurrent angina. Myocardial infarction occurred in nine of the 250 patients during the follow up period. Twenty six patients (10.4%) had reinvestigation for symptoms. This group had a graft occlusion rate of 52%. Half these patients have required reoperation and 20 of 22 occluded or severely stenosed grafts were replaced. In only two instances were vein grafts inserted into vessels with new disease. Half of the original group were given aspirin (330 mg three times a day) plus dipyridamole (75 mg three times a day). Of the 250 patients interviewed, 122 took aspirin and dipyridamole from the second postoperative day for a mean of 25 months, with warfarin for three months. The other 128 patients took placebo for a mean of 23 months together with warfarin for three months. This long term treatment with aspirin plus dipyridamole conferred no significant benefit for all clinical outcomes measured at a mean of 6.6 years.

Angina Pectoris↗
PubMed1988

The current place of coronary angioplasty.

The number of coronary angioplasty procedures performed worldwide has risen exponentially during the last decade partially reflecting a wider scope for the technique. This article reviews the present indications for coronary angioplasty.

Age Factors↗
PubMed1987

Ventricular septal rupture complicating myocardial infarction: is earlier surgery justified?

Fifty-five consecutive cases of ventricular septal rupture following myocardial infarction were reviewed in order to ascertain clinical and haemodynamic determinants of in-hospital mortality. Factors associated with a poor prognosis included clinical evidence of a poor haemodynamic state or biochemical evidence of impaired renal function. Twenty-six patients managed before 1982 (group 1) were then compared with 29 managed subsequently (group 2) when a policy of earlier surgical intervention had been adopted. Patients in group 2 were more haemodynamically compromised and had greater impairment of renal function. The surgical mortality in group 1 was 3 of 18 patients (17%) which was not significantly different from that in group 2 (7 of 22 patients, 32%). Earlier surgical intervention in ventricular septal rupture is frequently undertaken in critically ill patients whose prognosis is poor. However their surgical risk is not significantly increased and such an approach can therefore be justified as it may salvage some patients who otherwise would not survive.

Adult↗
PubMed1987

What proportion of patients with myocardial infarction are suitable for thrombolysis?

Four hundred and three patients were considered for entry into a trial of intravenous streptokinase in suspected myocardial infarction. Three hundred and sixty seven (91%) were excluded. Two hundred and sixty (65%) did not meet the inclusion criteria and 45 of the remaining 143 (35%) patients had contraindications to thrombolysis. This left 98 (24%) patients who were suitable for thrombolysis and 42 of them were over 70 years, the upper age limit. Thus according to this trial protocol 56 (14%) patients were eligible for recruitment; 36 (9%) patients were finally randomised. These data suggest that treatment with intravenous streptokinase may be applicable to only a small proportion of patients with myocardial infarction.

Adult↗
PubMed1986

Outcome of early surgery after coronary angioplasty.

Nineteen of 69 patients undergoing coronary angioplasty required immediate coronary surgery after the procedure. Six of these operations were planned as a result of angioplasty that failed without producing any complication. The remaining 13 cases were operated upon because complications occurred during angioplasty. These were coronary artery dissection in four, occlusion in five, continuing severe spasm in two, tamponade in one, and in one other detachment of a guidewire tip. In these 13 cases the vessel in which angioplasty had been attempted was the left anterior descending coronary artery in eight, the right in four, and the circumflex artery in one. This distribution was no different from that in the 56 patients without complications. There was one early postoperative death due to extensive anterior myocardial infarction, and there was electrocardiographic evidence of new infarction in three other patients. A mean of 16 months postoperatively, 16 of the 18 surviving patients had no cardiac symptoms, while angina had improved in the remaining two. Sixteen of the 18 patients had nuclear left ventricular angiography after a mean of 27 months. When the results of this investigation were compared with the left ventricular cineangiograms performed before angioplasty was attempted only two patients showed evidence of a new left ventricular wall motion abnormality. Prompt operation after complications of angioplasty is usually successful with good symptomatic relief and without left ventricular damage. The incidence of complications requiring operation, however, was high in this group of patients, most of whom had single vessel coronary artery disease.

Aged↗
PubMed1985

Randomised placebo controlled trial of aspirin and dipyridamole in the prevention of coronary vein graft occlusion.

Treatment with the combination of aspirin and dipyridamole is believed to reduce the incidence of coronary vein graft occlusion. A double blind randomised controlled trial was carried out in which aspirin 990 mg and dipyridamole 225 mg daily or placebo were added to the routine postoperative management (warfarin for three months) of 320 patients undergoing coronary bypass grafting. The trial treatment was given for 12 months, after which the results were assessed by coronary and graft angiography. The two randomised groups, each of 160 patients, were comparable in age, sex, symptomatic state, angiographic findings, and operative procedure. Repeat coronary arteriography was carried out on 266 patients, 133 in each group. All grafts and distal anastomoses were patent in 68% (91/133) of the placebo patients and in 75% (100/133) of those receiving active treatment. Overall graft patency was 87% (306/352) and 89% (342/385) respectively. Retrospective subgroup analysis showed patency rates of 72% (26/36) and 78% (39/50) of grafts to vessels requiring preliminary endarterectomy, and 80% (36/45) and 91% (40/44) of distal anastomoses to vessels measured at operation to have a diameter of less than or equal to 1 mm. None of these differences was significant at the 5% level. Thus in this group of patients with high graft patency rates, treatment with aspirin and dipyridamole conferred no appreciable advantage.

Adult↗
PubMed1984

Prognostic significance of coronary angiography.

In the London Chest Hospital coronary artery study, patients without coronary artery disease involving the main trunks or with an isolated single main vessel lesion had an annual mortality rate of 1.5%. Many of these were asymptomatic when investigated but may have previously suffered angina or myocardial infarction. The data further suggested that even in asymptomatic subjects, mild coronary artery disease is associated with an annual mortality of 0.9%. Its presence therefore is a powerful risk factor for further manifestations of disease and should preclude unrestricted certification to fly.

Aerospace Medicine↗
PubMed1984

Correlation of angiographic and surgical findings in distal coronary branches.

In 60 consecutive patients undergoing vein graft surgery the angiographic appearances of the coronary vessels were compared with those of the vessels at operation. On the basis of lumen diameter at the potential sites for grafting it was possible to predict with reasonable accuracy from examination of the angiogram which vessels were large enough to be grafted. Angiographic predictive accuracy was 82% and was similar both for vessels which filled normally and for those which filled by collaterals. The predictive value of the angiographic assessment was similar for branches thought to be too small (predictive value 74%) and for those considered sufficiently large (predictive value 85%) to receive a vein graft. Disease of the vessel walls was found at surgery (66% of coronary branches examined) more frequently than was predicted from the angiographic appearances (33%). Previous necropsy studies have found a high prevalence of coronary atheroma in the population, yet normal angiographic appearances in the coronary arteries are not uncommon in patients undergoing investigation for suspected coronary disease. The present study showed that atheroma may be present in coronary vessels without encroaching into the vessel lumen, so that it is not evident on the angiogram. Coronary atheroma is thus present more often and is more widely distributed in the coronary tree than is indicated by coronary angiography.

Arteriosclerosis↗
PubMed1984

Correlation of heart rate/ST slope and coronary angiographic findings.

The heart rate/ST slope was evaluated in 49 patients undergoing routine investigation for possible coronary artery disease. The slope correctly predicted the absence of any 75% stenoses in the seven patients to whom this applied; it was, however, correct for only four of 30 with one stenosis, one of 10 with two, and neither of the patients with three. Distinct slope ranges were not found, and the previously published ranges said to be specific for no significant stenosis and one, two, and three vessel disease were not.

Adult↗
PubMed1984

Comparison of Hexabrix 320 and Conray 420 for left ventriculography in patients with coronary artery disease.

We compared Hexabrix 320 (580 mOsm kg-1) with Conray 420 (2500 mOsm kg-1) for left ventriculography using a prospective randomised double-blind protocol. One hundred consecutive patients with suspected coronary disease were assigned to Hexabrix (52) or Conray (48) for left ventriculography (dose 10 ml m-2 BSA; flow rate 12 ml s-1). Thirteen patients found Hexabrix unpleasant compared with 24 receiving Conray; overall the feelings of warmth and discomfort were less with Hexabrix than Conray (p less than 0.01 and p less than 0.02 respectively). The incidence of nausea, vomiting, and hypersensitivity was similar. Angiographic quality was better with Conray than with Hexabrix (p less than 0.05). Average changes in heart rate and systolic pressure were similar, though there was greater variation in systolic pressure change after Conray (p less than 0.025). End diastolic pressure increased more after Conray than after Hexabrix (p less than 0.05). These slight advantages of Hexabrix over Conray may be valuable in patients requiring multiple angiograms or in those with impaired cardiac function, but do not justify its use for routine angiography.

Adult↗