Repeat thrombolysis for acute myocardial infarction.

BACKGROUND: Thrombolysis is still the first line of treatment for acute myocardial infarction in the United Kingdom. In a significant proportion of these patients thrombolytic therapy fails to restore patency of the occluded artery or is followed by early re-infarction. The best management of this group of patients is not clear although repeat doses of thrombolysis are commonly administered especially in the district general hospitals that do not have access to invasive facilities. We performed a retrospective clinical study to determine the outcome of repeat thrombolysis for acute myocardial infarction in patients with failed initial thrombolysis or early re-infarction. METHODS: Ninety-two patients who received two or more doses of thrombolysis for acute myocardial infarction were compared with 98 contemporary similar patients who received only one dose of thrombolysis. Case notes of all patients were examined for retrospective analysis. Main outcome measures were death, heart failure and need for in-hospital revascularization. RESULTS: Compared to the group thrombolysed once, in the rethrombolysed group there were significantly more deaths at 30 days (p=0.0016), more heart failure (with lower mean ejection fraction), more cardiac arrests as well as more frequent coronary angiography and percutaneous coronary interventions (PCIs). The incidence of haemorrhage in the two groups did not differ. CONCLUSIONS: The need for repeat thrombolysis identifies a group of patients with a high risk of early complications. Although repeat thrombolysis is safe, these patients then need close monitoring with a view to early intervention. For such patients admitted to district general hospitals without interventional facilities early referral to a tertiary center should be considered.

The heart failure revascularisation trial (HEART): rationale, design and methodology.

BACKGROUND: Most patients with heart failure due to left ventricular systolic dysfunction (LVSD) secondary to coronary artery disease (CAD) have evidence of myocardium in jeopardy (reversible ischaemia and/or stunning hibernation). It is not known whether revascularisation in such cases is safe or beneficial. AIMS: To determine whether revascularisation will improve the survival of patients with LVSD and heart failure secondary to CAD and myocardium in jeopardy. METHODS: This is a randomised controlled trial comparing revascularisation or not, in addition to optimal medical therapy with ACE inhibitors, beta-blockers, aldosterone antagonists and an anti-thrombotic agent. Patients must have heart failure requiring treatment with diuretics, a left ventricular ejection fraction <35% and evidence of coronary disease. Myocardial viability and ischaemia are assessed by a broad range of techniques including stress echocardiography and nuclear imaging. All imaging tests are reviewed in core laboratories to ensure uniform reporting. Any conventional revascularisation technique is permitted. The primary outcome measure is all cause mortality. Symptoms, quality of life and health economic issues will also be explored. Assuming an annual mortality of 10% in the control group and allowing for substantial cross-over rates, a study of 800 patients followed for 5 years has 80% power with an alpha of 0.05 (two-sided) to show a 25% reduction in mortality with revascularisation. RESULTS: At the time of writing 180 patients have been screened for inclusion, 111 have consented to participate and 70 have been randomised. The results of viability testing are awaited in 22 patients. Twenty-six patients had been investigated for myocardial viability and/or by angiography prior to consent, as part of the routine practice in that cardiology department. Of 68 patients who have completed assessment only after consent, 47 (69%) were included. The principal reason for drop-out between consent and randomisation was lack of evidence of myocardial ischaemia or hibernation. CONCLUSION: The HEART trial will help to determine whether investigation of myocardial ischaemia and/or viability with a view to revascularisation should become part of the routine care of patients with heart failure due to LVSD and CAD.

Does cardiologist- or radiographer-operated fluoroscopy and image acquisition influence optimization of patient radiation exposure during routine coronary angiography?

The operator of radiation exposure during coronary angiography varies between different centres. The purpose of this study was to explore whether radiation dose was lower during cardiologist- or radiographer-controlled radiation exposure and to determine if the grade of cardiologist performing angiography influenced radiation dose. Patients were randomly allocated either to cardiologist- or radiographer-controlled radiation exposure during coronary angiography. Screening time and radiation dose during fluoroscopy and image acquisition, measured by dose-area product meter, were recorded. Mean radiation dose during cardiologist-controlled radiation exposure (n=176) of 15.6 Gy cm(2) (95% confidence interval (CI), 14.4-16.8) was significantly lower than that produced by the radiographer-controlled group (n=192) of 17.3 Gy cm(2) (95% CI, 16.2-18.6) (p<0.044). There was no significant difference in screening times produced by the two groups of radiation exposure operators. The difference in radiation dose produced by the two operator groups was principally owing to exposure produced at image acquisition. Irrespective of radiation exposure operator, consultant cardiologists produced significantly lower screening times and radiation doses compared with registrars. During routine coronary angiography, radiographer-controlled radiation exposure does not reduce screening time or radiation dose. Senior cardiologists produce the lowest radiation doses during coronary angiography when they are responsible for radiation exposure.

Femoral complications and bed rest duration after coronary arteriography.

This randomized study using a pneumatic compression device found no significant difference in the femoral complication rate between 4 and 6 hours of bed rest after Judkin's coronary arteriography. The positive implications for the organization of an efficient service in busy tertiary centers include reduced patient discomfort, earlier ambulation and discharge, efficient staff deployment, and enhanced throughput.

Feasibility, accuracy and safety of magnetic resonance imaging in acute aortic dissection.

Magnetic resonance imaging (MRI) is the most accurate method of defining the morphology and haemodynamic features of thoracic aortic dissection. However, because of doubts about its safety in acute situations, its use has so far been confined to imaging chronic dissections. We present a prospective study of 50 patients thought clinically to have acute thoracic aortic dissection in which a rapid diagnosis was made by MRI.

Coronary artery disease in identical twins.

Coronary angiography in a pair of identical twins is described. Despite similarities in coronary risk factors, major differences were seen in both the anatomy and the degree of coronary disease.

Variant angina in thyrotoxicosis.

Thyrotoxicosis may exacerbate angina pectoris in patients with coronary artery disease but angina also occurs in thyrotoxic patients with normal coronary arteries. Four female severely thyrotoxic patients presented with apparent angina pectoris as a manifestation of their thyrotoxicosis. Two of them had transiently abnormal ECGs during pain. Treatment for thyrotoxicosis immediately stopped the chest pain, which did not recur. All patients had negative exercise ECGs, and one had a normal coronary angiogram. The possible mechanisms to explain this phenomenon are discussed. Coronary artery spasm has been demonstrated in thyrotoxic patients previously and may explain the features in these patients. An alternative hypothesis is that myocardial metabolism is fundamentally changed by thyrotoxicosis. We would recommend that thyroid function assessment should be considered in young female patients with atypical angina.

Changes in myocardial echo amplitude during reversible ischaemia in humans.

OBJECTIVE: This study investigated the changes in regional myocardial ultrasonic backscatter, measured as myocardial echo amplitude, that occur during reversible myocardial ischaemia in humans. DESIGN: Left anterior descending coronary angioplasty was used to produce reversible myocardial ischaemia in human subjects. Regional myocardial echo amplitude was studied in the interventricular septum and left ventricular posterior free wall before, during, and after coronary occlusion with the angioplasty balloon. Wall motion analysis of the left ventricle was performed from simultaneous cross sectional echocardiographic imaging. Patients were studied prospectively. PATIENTS: Six patients (mean age 56 (SD 11), range 46 to 69 years) with single vessel, left anterior descending coronary artery stenoses, were investigated during elective coronary angioplasty. A total of 11 balloon inflations were studied. SETTING: All patient studies were performed at Harefield Hospital. Echo amplitude analysis was performed at the Royal Brompton Hospital. INTERVENTIONS: Angioplasty was performed by the usual procedure at Harefield Hospital for elective coronary angioplasty. All routine medication including beta blockers and calcium antagonists were continued. Inflation pressures were up to 12 atm (1212 kPa) and mean inflation time ranged from 30 to 120 (86 (31)) s. In four studies the first inflation was examined, in three the second, in two the third, and in one each the fourth and fifth inflations. Echo amplitude and cross sectional echo-cardiographic studies were recorded with a 3.5 MHz Advanced Technology Laboratories (ATL) (720A/8736 series) mechanical sector scanner and an ATL Mark III (860-1 series) echocardiograph system with 45 dB logarithmic grey scale compression. MAIN OUTCOME MEASURES: Regional echo amplitude was examined in four regions of the left ventricle--namely, the basal and mid-septum, and basal and mid-posterior wall. Consecutive end diastolic and end systolic frames were analysed and cyclic variation was determined as the difference between the level of echo amplitude at end diastole and at end systole. Measurements were made before balloon inflation, at peak inflation, and after balloon deflation. Regional wall motion and systolic wall thickening were analysed qualitatively. RESULTS: Before balloon inflation, cyclic variation in echo amplitude was noted in all regions (basal septum, 2.4 (SD 1.1) dB; mid-septum, 2.5 (1.1) dB; basal posterior wall, 3.3 (2.1) dB; mid-posterior wall, 3.9 (1.6) dB). During balloon inflation there was a significant fall in cyclic variation to 0.4 (0.9) dB (p < 0.0002) in the mid-septum. This was predominantly owing to an increase in end systolic echo amplitude from 5.4 (2.0) dB to 9.3 (1.9) dB (p < or = 0.01). This was associated with the development of severe hypokinesis or akinesis in the mid-septum. No significant changes in echo amplitude occurred in the three other regions examined. Changes were completely reversed after balloon deflation. CONCLUSIONS: These results suggest a causal relation between occlusion of the supplying coronary artery and blunting of myocardial echo amplitude cyclic variation. It is suggested that balloon occlusion produced myocardial ischaemia. The resultant impairment of myocardial contraction then caused a blunting of cyclic variation in echo amplitude. The results of this study provide further data about the ability of quantitative studies of ultrasonic backscatter to identify alterations in the myocardium during injury.

Deterioration in left ventricular performance during early coronary angioplasty after thrombolysis. Evidence for myocardial salvage.

To investigate the effects of controlled coronary artery reocclusion after successful thrombolysis, we studied 15 patients during early elective angioplasty of the patent infarct-related artery. Eight patients underwent left anterior descending artery dilation, and the other 7 had right coronary artery dilation. In 13 cases, ST-segment elevation developed during balloon occlusion. In all 15 cases, intravenous digital subtraction left ventriculography during balloon inflation showed that the ejection fraction decreased at least 5% (mean decrease, from 60% to 47%), despite preexisting Q waves overlying the infarct territory in 5 patients. Balloon inflation resulted in decreased apical segmental shortening in all 8 patients who underwent left anterior descending artery dilation; likewise, balloon inflation produced impairment of inferior-wall contraction in all 7 patients who had right coronary artery dilation. In this setting, a deterioration in left ventricular performance indicates that the restoration of coronary patency with thrombolysis has resulted in myocardial salvage. In patients with Q waves, such deterioration suggests that this electrocardiographic abnormality does not necessarily indicate a completed infarction.

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.

Significance of "reciprocal" ST segment depression: left ventriculographic observations during left anterior descending coronary angioplasty.

To evaluate the significance of "reciprocal" ST segment depression resulting from coronary occlusion, 27 patients with single vessel coronary disease were studied with intravenous digital subtraction left ventriculography before and during angioplasty of the left anterior descending coronary artery. During balloon inflation, 13 patients developed inferior lead ST depression in addition to anterior lead ST elevation (Group 1), whereas the remaining 14 patients did not (Group 2). The degree of anterior lead ST elevation in Group 1 (5 mm) was greater than that in Group 2 (1.5 mm, p less than 0.001) as was the reduction in left ventricular ejection fraction (24% versus 13%, respectively; p less than 0.02). Anterior and apical regional shortening decreased in both groups similarly, but an additional decrease in anterobasal shortening was confined to Group 1 (from 38% to 21%; p less than 0.002). Despite the presence of inferior lead ST depression in Group 1, inferior regional shortening did not change and inferobasal contraction was enhanced (from 4% to 29%; p less than 0.01). Inferior lead ST segment depression during anterior descending coronary angioplasty reflects a greater degree of anterior wall ischemia. The concurrent preservation of inferior wall contraction and the augmentation of infero-basal shortening confirm that this electrocardiographic feature is a "reciprocal" phenomenon rather than a manifestation of remote ischemia.

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.

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.

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.