Duncan S. Dymond

Left ventricular aneurysm and congestive heart failure: value of exercise stress and isosorbide dinitrate in predicting hemodynamic results of aneurysmectomy.

In 12 patients with left ventricular aneurysm and chronic congestive heart failure, left ventricular functional reserve was assessed from the hemodynamic response to exercise stress after administration of isosorbide dinitrate. Two to 23 months (mean 8.6 months) after left ventricular aneurysmectomy hemodynamic measurements were made with the patient at rest and during exercise and were analyzed with respect to preoperative data. Left ventricular aneurysmectomy reduced mean left ventricular filling pressure from 25 to 17 mm Hg at rest (p < 0.02) and from 39 to 32 mm Hg during exercise (p < 0.05). There was no significant change in mean stroke volume index at rest or during exercise. Changes in resting and exercise hemodynamic indexes of left ventricular function produced by aneurysmectomy were inversely related to preoperative left ventricular function. Hence, hemodynamic status was less likely to improve In patients with good preoperative left ventricular function. Similarly, resting and exercise values for left ventricular function tended to improve in patients with reduced ejection fraction of the contractile section of the left ventricle. Left ventricular aneurysmectomy was generally effective in reducing left ventricular filling pressure but failed to achieve clinically important improvement in left ventricular performance during exercise. In patients with chronic congestive heart failure, left Ventricular aneurysmectomy should be performed only after careful assessment of preoperative left ventricular functional reserve.

High-risk coronary angioplasty with elective intra-aortic balloon pump support

Percutaneous transluminal coronary angioplasty was attempted with elective percutaneous intra-aortic balloon pump support in 21 patients (mean age 60 years, range 40-82; 18 males) with unstable angina (n = 2), multivessel coronary disease requiring multivessel angioplasty (n = 2), severe left ventricular dysfunction (ejection fraction 10-30%; n = 16) or ventricular fibrillation at diagnostic angiography (n = 1). Fourteen patients had 3-vessel disease (1 with vein grafts also diseased), 6 had 2-vessel disease and 1 had isolated left anterior descending disease. Twenty-five procedures were performed (one in 18 patients, two in 2 patients and three in one patient) on 42 lesions in 34 vessels/grafts. There was no angioplasty-related death. Successful dilatation was achieved in 38/42 lesions (90%) in 21/25 procedures (84%) without major complication. Three procedures were complicated: one by major coronary dissection without sequelae, one by haemodynamic deterioration due to distal occlusion and one by an unstable residual stenosis in the attempted vessel necessitating urgent bypass surgery. The only complication related to the intra-aortic balloon pump was local haematoma in 2 patients. In conclusion, elective intra-aortic balloon pump support may be safely used to stabilise high-risk patients undergoing coronary angioplasty, leading to a satisfactory primary success rate.

Effect on prognosis of abolition of exercise-induced painless myocardial ischemia by medical therapy☆

During exercise radionuclide ventriculography, many patients with coronary artery disease exhibit painless myocardial ischemia defined as an abnormal left ventricular ejection fraction response without accompanying angina. To see if complete suppression of such exercise-induced painless ischemia by anti-ischemic medication implies a better prognosis in medically treated coronary artery disease, 34 patients underwent repeat testing at 4 weeks receiving regular conventional therapy that rendered angina no worse than class I. With such therapy, painless ischemia was abolished in 12 patients (group I) and persisted in 22 (65%, group II). Both groups were similar in age, number of diseased vessels, proportion with previous myocardial infarction, exercise ejection fraction, and degree of exercise-induced painless ischemia at baseline. At 9 months, adverse events had occurred in 11 patients (2 patients with myocardial infarction, 4 with unstable angina, 2 with angioplasty and 3 with bypass surgery). Only 1 of 12 patients (8%) in group I had experienced events compared with 10 of 22 (45%) in group II (chi-square, 5.4; p less than 0.025; 95% confidence interval, 12 to 61%). Thus, the relative risk of adverse events in patients whose painless ischemia was abolished was only 18% of that in patients in whom it was persistent. These results suggest that (1) the abolition of exercise-induced painless ischemia by conventional symptom-dictated medical therapy confers a better short-term prognosis in medically treated coronary artery disease, and (2) therapeutic efficacy may need to be assessed by titration against ischemia and not against angina.

Combined exercise radionuclide and hemodynamic evaluation of left ventricular aneurysmectomy

Twelve patients were studied by rest and exercise radionuclide ventriculography following left ventricular aneurysmectomy (LVA). Left ventricular filling pressure (LVFP) was also measured. Nine patients had been studied pre-LVA at rest and exercise before and after isosorbide dinitrate (ISDN). Resting ejection fraction (LVEF) improved after LVA (p less than 0.25), but exercise LVEF did not. End-diastolic volume (EDV) and resting LVFP also fell after LVA (p less than 0.25 for EDV, p less than 0.05 for LVFP) and although exercise LVFP fell (p less than 0.02), the values were abnormal in all patients. Ejection fraction of contractile segment (EFCS) from the resting radionuclide study pre-LVA was related to resting LVEF post-LVA (r = 0.71 p less than 0.02), although postoperative LVEF could not be predicted from preoperative EFCS in individual patients. Deterioration in LVEF and LVFP from rest to exercise post-LVA occurred both in patients with single-vessel occlusion and in those with multivessel coronary disease, irrespective of whether or not revascularization had been performed. Thus LVA is effective in improving resting ventricular function; exercise performance may remain abnormal even in patients without residual coronary disease.

Detection of postinfarction left ventricular aneurysms by first pass radionuclide ventriculography using a multicrystal gamma camera.

Eighteen patients with a history of previous anterior myocardial infarction and suspected left ventricular aneurysms were studied both by contrast left ventriculography and by first pass radionuclide ventriculography using Technetium99m and a computerised multicrystal gamma camera. The radionuclide study successfully identified all 14 patients with aneurysms and all 4 with diffusely hypo-kinetic ventricles. Ejection fraction calculated from the change in radioactive counts in the left ventricle correlated well with that calculated from the area-length method from the contrast angiogram (r = 0.83). Ventricular volumes calculated from the area-length formula for both contrast and radionuclide angiograms correlated closely (r = 0.85 and r = 0.89 for end-systolic and end-diastolic volumes, respectively). In the patients with aneurysms, there was a close correlation between the extent of akinesis, as assessed by the two methods (r = 0.94). The ability of the radionuclide ventriculogram to provide accurate information on global and segmental ventricular function, and to differentiate between segmental and diffuse ventricular dysfunction, enables the method to act as a screening procedure in the investigation of patients with suspected left ventricular aneurysms.

Temporal evolution of changes in left ventricular function induced by cold pressor stimulation. An assessment with radionuclide angiography and gold 195m.

The evolutionary changes in left ventricular function induced by cold pressor stimulation were investigated at 90 second intervals by rapid sequential first pass radionuclide angiography using the short half life tracer gold 195m. The results in 12 subjects with normal coronary arteries were compared with those in 12 patients with coronary artery disease. Left ventricular ejection fraction fell significantly from resting values in both groups after 1 minute of cold pressor, but only in patients with coronary disease was the significant fall maintained at 2.5 and 4 minutes. In both groups, the maximum decrease in ejection fraction occurred after 1 minute, whereas the maximum rise in systolic blood pressure occurred after 2.5 minutes. New abnormalities of regional ventricular function developed in 10 normal subjects after 1 minute of cold, with a total of 12 new abnormal segments. Only two such segments were seen at the later stages of imaging. Twenty one new segments developed after 1 minute in the coronary disease group, and 13 segments remained abnormal after 4 minutes. Three patients, two of whom had left main stem stenoses, showed persistent abnormalities of ventricular function after 2 minutes of recovery from cold stimulation. Thus left ventricular function changes rapidly during a period of cold stimulation in both those without and those with coronary disease. When the cold pressor test is used with multiple gated equilibrium imaging, the timing of imaging may be crucial to the results and interpretation of the test. The discordance between functional changes and rise in blood pressure is further evidence that alterations in afterload are not solely responsible for cold induced abnormalities.

Exercise testing without interruption of medication for refining the selection of mildly symptomatic patients for prognostic coronary angiography.

OBJECTIVE--To examine how exercise testing on background medical treatment affects the ability of the test to predict prognostically important patterns of coronary anatomy in patients with a high clinical probability of coronary artery disease but who are well controlled on medication. DESIGN--Prospective study. SETTING--Regional cardiothoracic centre and referring district general hospital. PATIENTS--84 patients with a history of typical angina or definite myocardial infarction and mild symptoms who had been placed on the waiting list for prognostic angiography. INTERVENTION--Maximal exercise electrocardiography and radionuclide ventriculography performed off and on medication, followed by angiography within three months. MAIN OUTCOME MEASURE--Prognostically important coronary artery disease for which early surgery might be recommended purely on prognostic grounds, irrespective of symptoms. RESULTS--Coronary artery disease was present in 71/84 (85%) patients; in 28/84 (33%) patients this was prognostically important. When the result was strongly positive, the predictive accuracy for prognostically important disease was 0.46 off and 0.62 on medication for the exercise electrocardiogram and 0.71 off and 0.82 on medication for exercise radionuclide ventriculography. The likelihood ratio was 1.00 off and 1.36 on medication for exercise electrocardiography and 2.54 off and 10.5 on medication for exercise radionuclide ventriculography. In stepwise logistic regression, the test identified as the strongest predictor of prognostically important disease was exercise radionuclide ventriculography on medication for which the improvement chi 2 was 28 (p < 0.0001). With the regression model, the probability of important disease is 92% if exercise radionuclide ventriculography on medication is at least strongly positive, compared with 16% if the result is normal or just positive. CONCLUSION--In patients likely to have coronary disease, exercise testing should be performed without interruption of medication to optimise its ability to identify those with prognostically important disease, and to help to avoid unnecessary or premature angiography in those who are well controlled on medical treatment.

Dual isotope stress testing in congenital atresia of left coronary ostium. Applications before and after surgical treatment.

A 38-year-old women presented with an 11-year history of angina pectoris. Coronary arteriography disclosed a large right coronary artery which filled the entire left coronary tree retrogradely. The left main coronary artery ended blindly and was not connected to the aortic root. There were no atherosclerotic lesions in any vessel. Exercise thallium-20l scintigrams showed a perfusion defect in the anterior region of the left ventricle and exercise first pass radionuclide ventriculography showed anterior hypokinesis of the left ventricle with an ejection fraction of 54 per cent, compared with 60 per cent at rest. An aortocoronary saphenous vein graft was constructed to the left coronary artery. Four months after operation the patient is free from symptoms. Repeat thallium scintigrams were normal. Exercise radionuclide ventriculography after operation disclosed no wall motion abnormality, and ejection fraction on exercise was 70 per cent. The mechanism of angina in this patient is unclear but may have been related to the abnormal timing of delivery of blood to the left ventricular myocardium. Dual radionuclide stress testing showed abnormalities after operation. This non-invasive approach may be useful in the assessment of the physiological significance of coronary anomalies and of the value of corrective surgery.

Platelet IIb/IIIa antagonists followed by delayed stent implantation. A new treatment for vein graft lesions containing massive thrombus

The percutaneous treatment of saphenous vein graft lesions containing angiographically massive thrombus is associated with a high risk of distal embolisation and no-reflow. The optimal management for these lesions remains unclear and a challenge to the interventional cardiologist. Five cases are described in whom the risks of percutaneous angioplasty were felt to be excessive owing to a high thrombus load. Each case was treated with a bolus and infusion of abciximab (ReoPro; Eli Lilly—a platelet glycoprotein IIb/IIIa receptor antagonist) at least 24 hours before further angiography. Repeat angiography of the culprit vein graft, following treatment with abciximab alone, demonstrated a major reduction in the thrombus score and the presence of TIMI 3 flow in each case. Immediately following repeat angiography, angioplasty with stent insertion was performed successfully with no distal embolisation or no-reflow phenomenon. This staged approach, with abciximab used alone to reduce thrombus load, is a new treatment for vein graft lesions containing massive thrombus.

The clinical validation of gold-195m: A new short half-life radiopharmaceutical for rapid, sequential, first pass angiocardiography in patients

With technetium-99m radiopharmaceuticals, first pass radionuclide angiocardiography is of limited use for multiple intervention studies because of the large radiation burden imposed on the patients. A portable mercury-195m/gold-195m generator has been developed capable of producing 17 to 20 mCi aliquots of the short half-life (30.5 seconds) gold-195m in less than 0.5 ml of generator eluate. Safety of the eluate has been established both in the experimental animal and in human beings. Fifteen patients underwent two first pass radionuclide angiograms with gold-195m, followed by a standard technetium-99m study. There was a close correlation between the left ventricular ejection fraction measured from gold and technetium studies (correlation coefficient [r] = 0.99, standard error of the estimate [SEE] 3.1%). Interobserver and sequential reproducibility of gold studies were excellent (mean variability ± standard deviation [SD]2.0 ± 2.9 and 0.6 ± 2.7%, respectively). Statistical reliability of the gold studies, as assessed from the observed left ventricular end-diastolic counts, matched that of technetium studies, and similarly, the images obtained from the two radiopharmaceuticals were identical. Residual count rates 5 minutes after first pass acquisition with gold were 480 ± 140 counts/s in the whole field of view, and 50 ± 30 counts/s over the left ventricle, these values being less than 1% of the residual counts after technetium. Accurate, reproducible, high count-rate first pass studies are obtainable with gold-195m, with a markedly reduced radiation exposure to the patients. It is now possible to perform rapid sequential first pass cardiac imaging studies without the constraints of an unacceptable high radiation burden.