J E Wright

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.

Reoperation for angina after previous aortocoronary bypass surgery.

A retrospective study was carried out of the outcome of 102 patients who underwent a second operation for myocardial revascularisation, necessitated by persistence or recurrence of intractable angina after their first coronary bypass procedures. Operative mortality was 2%. During follow up of the survivors (mean interval 36.4 months) five died, two after further operation, and five underwent further surgery. Sixty eight patients reported an improvement in their symptoms, 57 of whom claimed to have little or no angina. Less favourable results were recorded for those patients reviewed with longer follow up. No useful indicators of prognosis were identified. The problem of angina in patients who have already received bypass grafts is likely to increase as more revascularisation surgery is performed. Reoperation offers a reasonable prospect of helping some of these patients, but not all will be suitable. Their long term prognosis remains uncertain.

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.

Reoperation for recurrent angina.

Forty patients with persistent or recurrent angina after an aortocoronary bypass procedure underwent a second operation. The cause of recurrent angina, defined by angiography, was thought to be isolated graft failure in 13 patients, progression of disease in ungrafted vessels in 4, incomplete revascularisation in 2, and stenoses distal to patent grafts in 1. More than one factor was responsible in 20 patients. There was 1 early postoperative death and 3 perioperative myocardial infarctions. Thirty-four patients have been followed for more than 3 months (4 to 63 months). Of these, 17 had previously bypassed vessels regrafted and 5 are sympton free, 4 have mild angina, and 8 have severe angina. Ten patients had previously ungrafted vessels grafted and 4 are sympton free, 3 have mild angina, 2 have severe angina, and 1 is limited by breathlessness. Seven patients had a combined procedure and 4 are sympton free, 1 has mild angina, and 2 have severe angina. Reoperation can be carried out safely but the results are less satisfactory than for a primary procedure.

Results of surgical repair for dissection of the ascending aorta.

Between 1970 and 1986, 40 patients had surgical treatment for dissection of the ascending aorta at the London Chest Hospital. The overall hospital mortality was 27.5%. Preoperative renal impairment and age greater than or equal to 60 years were both associated with a significantly increased hospital mortality. In the long term one patient was lost to follow up. There have been two late deaths among the remaining 28 patients (mean follow up 4.4 years). The functional state of the survivors is good, with only three having any cardiac disability.

Clinical experience with left main coronary artery stenosis.

We report the clinical features and the results of investigation and surgery in 20 patients with significant left main coronary artery stenosis. All had moderate to severe angina; 8 had pain at rest. Three had dyspnoea as a major symptom. The electrocardiogram was abnormal in 17, with evidence of previous myocardial infarction in 10. Of the 11 patients exercised, 8 developed chest pain. Nine patients had a normal left ventriculogram. At coronary angiography all patients had major disease elsewhere in addition to the left main coronary artery stenosis. There were no deaths or major complications associated with this investigation. One patient was unsuitable for surgery because of diffuse left ventricular hypokinesia, one had a fatal myocardial infarction while awaiting operation, and there was one preoperative death. Sixteen of the 17 surgical survivors are free from angina. There has been a significant improvement in the maximum exercise capacity in the 10 patients who had pre- and postoperative exercise tests.

Surgical treatment of postinfarction left ventricular aneurysm in 32 patients

Thirty-two patients with large postinfarction left ventricular aneurysms shown at operation to consist of fibrous tissue are reported. All had angina and/or breathlessness, and none had a history of embolism. Thirty were correctly diagnosed by left ventricular cineangiography. Two of the 3 patients with inferior and 1 with an anterior aneurysm had associated ventricular septal defects, and 3 patients with an anterior aneurysm had mitral regurgitation. All had major coronary arterial lesions and 68 per cent had double or triple vessel disease. The aneurysm was excised in all patients; in 15 this was combined with saphenous vein bypass grafting of coronary arteries supplying surviving myocardium, in 3 with closure of a ventricular septal defect, and in 3 with mitral annuloplasty or replacement. Operative mortality was 6-2 per cent, and 79 per cent of the survivors are asymptomatic with average follow-up period of 18 months after operation.

Evaluation by exercise testing and atrial pacing of results of aorto-coronary bypass surgery.

The results are reported of investigation and surgery in 1O9 patients with angina pectoris who have undergone aorto-coronary bypass surgery. There were 7 hospital and no late deaths. Of5opatientsfollowedfor more than 6 months, 36 became symptomfree and afurther 12 improved. This clinical improvement was accompanied by significant increase in exercise performance which was related to the preoperative state of the left ventricle. Thirty-three patients were catheterized postoperatively and in this group also clinical improvement correlated well with the results of exercise and pacing tests. Of 52 grafts, 43 (83%) were patent and there was a close association between evidence of revascularization and clinical result.

Cardiac pain at rest. Management and follow-up of 100 consecutive cases.

One hundred consecutive patients, admitted to the coronary care unit with cardiac pain at rest but no evidence of recent myocardial infarction have been followed up for nine to 26 (mean 14) months. They were treated initially with bed rest, beta-adrenergic blockade, and nitrates. In 54 patients pain subsided within 24 hours. Coronary angiography was carried out in 46. Thirty-five had coronary artery lesions and three had spasm in normal coronary arteries. One had hypertrophic cardiomyopathy and seven had normal findings. Seventeen patients with previous angina and severe coronary disease were operated on, with one death and one perioperative infarction; two died late, 12 were symptom free, and two had angina. Seven of 18 patients treated medically had recurrent angina and underwent operation. Of the 11 unoperated patients, one died, three had angina, and seven were symptom free. Two of the eight patients who were not catheterised developed infarction, four had angina, and three were symptom free. Recurrent pain continued for more than 24 hours in 46 patients, and all underwent angiography. Forty-three had coronary artery disease and 34 underwent early bypass surgery; there were two operative deaths and three perioperative infarctions. Twenty-six symptom free at follow-up. Of the nine unoperated patients with coronary disease, four developed infarction, two were operated on for recurrent angina, two were symptom free, and one had mild angina. Optimal management of patients with pain at rest can be determined only with knowledge of the coronary artery anatomy and of left ventricular function. Many respond initially to intensive medical treatment and coronary angiography can be performed electively. In those with continuing pain, urgent angiography is required and can be done safely.

Results of aortocoronary bypass operations. Follow-up in 343 patients.

Three hundred and forty-three patients who had aortocoronary bypass graft operations for disabling angina were followed up for from 6 months to 5 years (average 2 years). 80 per cent had multiple grafts and 20 per cent had additional endarterectomy. The overall mortality within one month of operation was 5 per cent, and in those who had vein graft procedures only was 4 per cent. 11 per cent had a postoperative myocardial infarction (6% perioperative) and there were 3 per cent late deaths. At 3 years 90 per cent are surviving. 80 per cent are asymptomatic without treatment. The mean angina grade was 0.3 at the latest follow-up, compared with 2.5 before operation; maximum exercise tolerance was also significantly improved (P less than 0.001). When angina recurred, it did so in 80 per cent of the cases within 12 months of operation and was usually attributable to inadequate revascularisation. Ventricular function as assessed by preoperative ventriculography was the factor most clearly related to survival rate and the early excellent results of coronary bypass operations seem to be maintained up to 5 years. It is, therefore, reasonable to continue to advise operation if only for relief of angina.