Christian Landou

PLASMINOGEN ACTIVATOR INHIBITOR IN PLASMA: RISK FACTOR FOR RECURRENT MYOCARDIAL INFARCTION

Measurements of haemostatic function and metabolic and angiographic indices of risk were included in a prospective cohort study of variables predictive of recurrences within 3 years in 109 unselected men with a first myocardial infarction (MI) before the age of 45. In the course of follow-up, 16 patients had at least one reinfarction (fatal recurrences in 9 and nonfatal in 7) and 1 died suddenly. High plasma concentrations of the fast-acting plasminogen activator inhibitor were independently related to reinfarction along with dyslipoproteinaemia involving VLDL and HDL, poor left ventricular performance, and multiple-vessel coronary artery disease. Besides being independently associated with reinfarction in the present population, high triglyceride levels were possibly connected with a predisposition to thrombosis through a coexisting high level of plasminogen activator inhibitor. The data indicate that reduced fibrinolytic capacity due to increased plasma levels of the plasminogen activator inhibitor predisposes to reinfarction in a complex interplay with atherogenic factors, multiple coronary lesions, and compromised left ventricular function.

Minimum heart rate and coronary atherosclerosis: Independent relations to global severity and rate of progression of angiographic lesions in men with myocardial infarction at a young age

The relations of hemodynamic factors, plasma fibrinogen concentration, serum lipoprotein levels, and clinical risk indicators to coronary atherosclerosis were studied in 56 men who had survived a first myocardial infarction before the age of 45 years and who subsequently underwent two coronary angiographies with an intervening time interval of 4 to 7 years. Presence, severity, and rate of progression of both diffuse lesions and distinct stenoses were determined by means of separate classification systems in 15 proximal coronary arterial segments. High minimum heart rate measured during a 24-hour period in connection with the reangiography was associated with progression of both diffuse lesions and distinct stenoses. High minimum heart rate also correlated positively with angiographic scores of global severity of diffuse atherosclerosis and stenoses. Progression of disease was predicted independently by minimum heart rate and low-density lipoprotein/high-density lipoprotein ratio, whereas lipoprotein A, fibrinogen levels, hypertension, smoking, and beta-adrenergic receptor blockade treatment did not discriminate between patients with and without progression.

Early and Late Patency of Aortocoronary Vein Grafts

Early patency (two weeks) of 331 aortocoronary vein grafts was 89%. Late patency (one year) of 122 restudied grafts was 80%. A cumulative one year patency of 72% was calculated. Patency was similar for SV grafts, sutured distal to stenosis and segmental obstruction. Early patency was significantly decreased when the peroperative graft blood flow was 20 ml/min or less or the diameter of the recipient coronary artery was smaller than 1.5 mm. Cumulative one year patency was lower in symptomatic patients (54%) than in those who underwent consecutive reevaluation (80%). There was a trend towards improved patency rates for graft anastomosed to the left anterior descending coronary artery and grafts without pre-existing pathological changes. Patient parameters, such as at operation, sex, smoking habits, hypertension, lipid abnormalities, diabetes, previous myocardial infarction or depressed left ventricular function, had no bearing on patency. Graft failure occurring, despite refined surgical technique, is usually due to pathological changes of the vein graft per se or the recipient coronary artery and its vascular bed.

ANGIOGRAPHIC CHANGES IN INTERNAL MAMMARY ARTERY AND SAPHENOUS VEIN GRAFTS, TWO WEEKS, ONE YEAR AND FIVE YEARS AFTER CORONARY BYPASS SURGERY

Coronary angiography was performed two weeks after coronary bypass surgery on 112/121 consecutive operative survivors (93%), on 97/119 one-year survivors (82%) and on 79/108 five-year survivors (73%). Occlusions of the grafts were uncommon after the first year. The cumulative five-year patency, calculated with the actuarial method, was 89% for internal mammary artery (IMA) grafts and 77% for aortocoronary saphenous vein (SV) grafts. Almost 70% of the SV grafts exhibited a 15-50% reduced diameter after one year and 10% showed progressive narrowing at five years. Diffuse luminal narrowing did not predict graft failure. The incidence of localized narrowings present at two weeks after surgery was, however, significantly higher among SV grafts, which occluded within one year, than among those patent after five years. In 5% of the IMA grafts the diameter was reduced 15-80% after five years. This was related either to obstruction at the anastomotic site or to low-grade proximal coronary stenosis. No less than 12% of the IMA grafts increased 20-50% in diameter as an adaptation to good distal runoff.

Late Thrombotic Malfunction of the Björk–Shiley Tilting Disc Valve in the Tricuspid Position. Principles for Recognition and Management

Among 52 consecutive patients surviving tricuspid valve replacement with the Björk-Shiley tilting disc valve, follow-up extends between 1/2-9 years, mean 4.9 years. Four patients suffered thrombotic obstruction of their tricuspid prosthesis on 8 occasions, an incidence of 3.2%/year. Ebsteins anomaly and deficient anticoagulation were identified as likely contributory factors, but the complication remained unexplained in 2/8 instances. Thrombotic malfunction of the tricuspid prosthesis seems to constitute a relatively benign clinical entity with mild manifestations and diagnostic possibilities by non-invasive methods. Relief by means of thrombolytic treatment in the form of streptokinase (Kabikinase) (4) or replacement of the clotted prosthesis (4) involved neither disabling complications nor mortality. Our clinical observations and experimental studies suggest that thrombolytic therapy is effective, provided that prosthetic malfunction is due to a recent red clot, whereas encapsulation of the prosthetic disc by organized white-grey pannus necessitates re-operation. Streptokinase treatment should be attempted before surgery, but it is hardly meaningful to proceed for more than 24 hours. Restored prosthetic function within this time limit indicates the likely resolution of a red clot.

Indications for the Internal Mammary Artery Graft

Experience of 285 internal mammary artery (IMA) grafts inserted during a five-year period disclosed an operative mortality of 1.5% when patients with associated procedures were excluded. Two of nine patients undergoing concomitant intracardiac surgery died within one month. Thus the overall operative mortality was 2.1%. Preoperative IMA graft blood flow was significantly less than that through comparable aortocoronary saphenous vein grafts. Early IMA graft patency (two weeks) was 95% and the cumulative late patency (one year) was 91%. Early patency for IMA grafts with peroperative flow less than 20 ml was 70%. None of these grafts were occluded at late follow-up. Sixteen occluded IMA grafts were related to technical problems (six grafts), inadequate graft size (five), extensive disease of the recipient coronary artery (four) and to overestimated proximal stenosis with large competitive flow enhancing early graft failure (one graft). Retrograde filing of the IMA when contrast was injected into the recipient coronary artery, was observed in 7 patients (3%). Probable causes were proximal stenosis of the graft, small sized IMA with inadequate antegrade flow and overestimated proximal coronary obstruction. Prerequisites for performing optimal IMA grafting need pre- and peroperative caution. A good calibre IMA without proximal obstructions must be available. The technique of dissecting and handling the vessel and performing anastomosis must be careful. The recipient coronary artery should be selected with consideration in order to avoid unfavourable demand-supply ratios. The IMA is most suitable for low-flow situations supplying a small amount fo myocardium distal to a high-grade coronary obstruction.

Coronary endarterectomy—angiographic and clinical results

Of 75 patients who underwent coronary endarterectomy, 16% had left main stem stenosis, 4% one-vessel, 27% two-vessel and 53% three-vessel disease. On average 2.9 grafts per patient were inserted, in conjunction with 82 manual endarterectomies (38 right coronary, 35 left anterior descending, 9 circumflex branches). In 68/75 cases (91%) the endarterectomy was not preplanned and in 39 cases (52%) greater than or equal to 3 cm of the atherosclerotic core was removed. All four early deaths (5%) followed endarterectomy of LAD. Acute perioperative myocardial infarction was confirmed in 19% and probable in further 8%. At angiography 1-139 (median 25) months postoperatively, all three internal mammary artery grafts and 19/34 saphenous vein grafts (56%) to endarterectomized vessels were patent, though in 4 of the 19, the coronary artery was occluded distal to the anastomosis. In addition 17/18 conventional internal mammary artery (94%) and 48/59 conventional saphenous vein grafts (81%) were patent. The vein graft patency rate was not significantly influenced by postoperative anticoagulant therapy, but was significantly increased among patients with relief of angina: 44% reported freedom from angina and 92% at least some relief after a median of 3 years. The 5-year and 10-year survival rates were 85% and 68%. Despite the increased risk, endarterectomy can be recommended for severely diseased major coronary arteries.

Changes in Coronary Artery Disease Five Years After Coronary Bypass Surgery

Seventy-nine patients underwent repeat coronary angiographies five years after coronary bypass surgery. Ninety-eight of 122 inserted grafts (80%) were patent. Significant coronary obstruction (greater than 50% reduction of luminal diameter) developed in 43/79 patients (54%) and was associated with a longer duration of angina before surgery and a lower diastolic blood pressure at the five-year follow-up, but significantly related to such factors as age, sex, type of angina, previous myocardial infarction, hypertension, hyperlipaemia, diabetes or smoking. The total number of significant obstructions increased from 230 to 308 (34%). Progression of pre-existing changes to occlusion was common and the number of occlusions increased 95% in non-grafted arteries compared with 48% in grafted arteries until the five-year evaluation. Fifty-seven of 81 new significant obstructions (70%) were found in non-grafted coronary arteries. The proximal part of the right coronary artery was most commonly affected with 19/57 (33%) of these new obstructions. A significant stenosis regressed in three patients. At the five-year follow up, 74/79 patients (94%) had less symptoms than before operation and 27/79 patients (34%) were asymptomatic. Nine patients had no angina, despite non-bypassed significant obstructions. All grafts were patent in 25/27 asymptomatic patients (93%) and in 38/52 (73%) of those with angina. Two patients had no anginal symptoms, despite occluded grafts. One had sustained a myocardial infarction and the other had symptoms of left ventricular failure. Well-developed collateral vessels were observed in 15/27 asymptomatic patients (56%) and in 45/52 (87%) of those with angina. Recurrence of symptoms was related to progressive coronary disease, graft occlusions, obstruction of anastomoses, non-bypassed obstruction or combinations of these changes.

EXERCISE TOLERANCE FIVE YEARS AFTER CORONARY BYPASS SURGERY IN RELATION TO CLINICAL AND ANGIOGRAPHIC FINDINGS

Exercise on a bicycle ergometer was used to assess symptom-limited working capacity (Wsl) five years after coronary bypass surgery. Ninety-six patients were evaluated with a sitting bicycle test using 10 Watt increments of work load every minute from an initial load of 10 Watt. Ninety-three per cent had less symptoms than before surgery and 32% said they had no angina. Angina was provoked at exercise in 1/31 asymptomatic patients (3%) and in 46/65 (71%) of those with residual symptoms. The Wsl of 50-250 Watt (mean 143 Watt) in a asymptomatic patients was significant higher than 30-220 Watt (mean 105 Watt) performed by patients with residual angina. In 61 patients, exercise tests were performed before, one year and five years after the operation. Average Wsl was significantly higher after one year (127; 36 Watt) than before surgery (90; 23 Watt). but declined significantly until the five-year evaluation (113; 37 Watt). After one year 82% had a higher Wsl than prior to operation compared to 69% five years after surgery. Angiography five years after surgery revealed that 60/76 subjects (79%) had all grafts patent and 16/76 (21%) one or more grafts occluded. In spite of one or more grafts occluded. 2/16 patients (13%) were asymptomatic, whereas 25/60 (42%) with all grafts patent were free from symptoms. Average Wsl was significantly higher in patient with all grafts patent (130; 44 Watt) compared to patients with one or more grafts occluded (102; 33 Watt). It is concluded that although subjective improvement after coronary bypass surgery persisted in about 90% of the patients for five years, bicycle exercise tests show a significant decline of Wsl after the first year, but five years after surgery was still better than before the operation.

Left Ventricular Pump Function Before and After Aortocoronary Bypass Surgery

Ten patients with severe effort angina and with left ventricular dysfunction during exercise before operation underwent haemodynamic and angiographic studies in average 20 months after coronary artery bypass surgery. Five patients (50%) were completely asymptomatic after operation(group I). The other five (group II) were still limited physically because of anginal pain, although two were much improved. Pre-operatively there was no significant difference in the severity of the disease, as judged from case histories, work tests and haemodynamic and angiographic findings between the two groups. The working capacity of the patients in group II was not increased significantly post-operatively. Their coronary arteriograms revealed unsatisfactory surgical results. In two patients, one significantly stenosed vessel was not bypassed because of poor run-off. In the other three patients, one graft was closed. Left ventricular function curves showed no significant improvement of left ventricular pump function. In group I, working capacity increased significantly, all stenoses of major coronary vessels were bypassed and all grafts were patent. Left ventricular function showed an almost normal response during exercise. These findings suggest that left ventricular dysfunction due to ischaemia can be significantly improved by coronary bypass and that there is a good correlation between clinical, haemodynamic and angiographic findings.