Robert Ponlot

Haemostasis disorders in open heart surgery with extracorporeal circulation. Importance of the platelet function and the heparin neutralization.

Abstract. The main haemostasis changes observed in a screening study performed in 40 patients who underwent an open heart surgery with extracorporeal circulation (ECC) are: a significant drop in platelet count from the onset of the ECC to the third postoperative day, a decrease of platelet retention and aggregation during ECC with an 8‐day persistently increased heparin‐neutralizing activity in plasma but not in serum, a moderate decrease of plasma factors I, II, VII‐X, X and XIII and a more important drop in factor V which disappears 24 h after ECC, a transitory increase of fibrinolysis during ECC and the lack of FDP elevation in the serum. These disorders require a very good neutralization of the heparin used during ECC. The ratio protamine/heparin can be established by a titration clotting time test. Protamine chloride seems to be more efficacious and to act more quickly than protamine sulfate for the neutralization. An overload in protamine can enhance the hemostatic, biological and clinical disorders. The preventive administration of platelet concentrate immediately after the heparin neutralization contributes to reduce the bleeding disorders related to the quantitative and qualitative platelet defects.

Haemostasis Disorders in Open Heart Surgery with Extracorporeal Circulation

The main haemostasis changes observed in a screening study performed in 40 patients who underwent an open heart surgery with extracorporeal circulation (ECC) are : a significant drop in platelet count from the onset of the ECC to the third postoperative day, a decrease of platelet retention and aggregation during ECC with an 8-day persistently increased heparin-neutralizing activity in plasma but not in serum, a moderate decrease of plasma factors I, 11, VII-X, X and XI11 and a more important drop in factor V which disappears 24 h after ECC, a transitory increase of fibrinolysis during ECC and the lack of FDP elevation in the serum. These disorders require a very good neutralization of the heparin used during ECC. The ratio protamine/heparin can be established by a titration clotting time test. Protamine chloride seems to be more efficacious and to act more quickly than protamine sulfate for the neutralization. An overload in protamine can enhance the hemostatic, biological and clinical disorders. The preventive administration of platelet concentrate immediately after the heparin neutralization contributes to reduce the bleeding disorders related to the quantitative and qualitative platelet defects.

Orthotopic heart transplantation in situs inversus.

The case of a successful orthotopic heart transplantation for complete situs inversus with double-inlet left ventricle and anomalies of the systemic venous return is reported. A piece of aortic homograft and a composite conduit made of the recipient right atrium and pericardium were used to connect, respectively, the left superior vena cava and the hepatic veins to the right-sided atrium of the donor heart.

Perigraft seroma following axillofemoral bypass: report of three cases.

One hundred and twenty-three axillofemoral or bifemoral bypasses were performed in the Department of Cardiovascular and Thoracic Surgery of the Catholic University of Louvain, Belgium between 1975 and 1986. Three cases of perigraft seroma were noted. A polytetrafluoroethylene (PTFE) graft had been inserted in all three cases. In one case, the seroma recurred rapidly after surgical drainage. The two others were not drained. In all three cases appearance remained unchanged throughout the observation period. The three bypasses are patent at 5, 14 and 24 months. Observation is advocated for this complication especially in high risk patients.

Morphology and fibrinolytic activity of canine autogenous mesothelium used as venous substitute

SummaryAutogenous mesothelium was used as venous substitute in ten dogs. Patches of mesothelium of three different origins were grafted into the anterior wall of the common iliac veins (CIV): peritoneum taken from and including the posterior rectus sheath (PRS), simple peritoneum (P) and mesentery (M). Animals were killed after 2, 4, 8, and 16 days and after 3 months. The segments of CIV, including the patches, were removed for study.On light microscopy, the PRS grafts showed a normal mesothelium but marked submesothelial fibrosis. The M and P grafts showed normal mesothelium and only mild fibrous thickening. On scanning electron microscopy, there was a perfect continuity of the mesothelial cells and the normal endothelium at the suture line. In the center of the graft, the cells had become elongated along the axis of blood flow. Fibrinolytic activity (FA) was measured by a standardized fibrin plate technique and quantitated in tissue activator units per gram of tissue (TAU/g). The mean FA of iliac vein specimens was 1101.7 ± 133.3TAU/g (mean±SEM). The mean FA determined before grafting for each kind of mesothelium was the following: PRS = 418.8±26.9TAU/g; P = 873.0±107.1TAU/g; M = 1142.3 ± 91.4TAU/g where only PRS showed values significantly lower than iliac vein mean FA (P < 0.001). Postoperatively, the mesothelial FA, after an initial reduction, increased on day 4 and reached values significantly higher than the control values (1445.7±204.1TAU/g tissue vs 853.1±62.3 TAU/g tissue;P < 0.001).The morphologic adaptation and the maintained fibrinolytic activity of mesothelial cells in the venous system suggest that they can replace endothelium.

Haemodynamics during maximal exercise after coronary bypass surgery

Fifty patients underwent an objective measurement of physical working capacity by means of a multistage test of maximally tolerated exertion before and after coronary bypass surgery; 29 patients also had haemodynamic measurements during maximal exercise before and after coronary bypass surgery. The patients were divided into 3 groups according to the degree of revascularisation: adequate (n = 20), partial (n = 17), or none (n = 13). Adequate revascularisation induces a large increase in physical working capacity because of an increased maximal heart rate and maximal cardiac output; stroke volume during maximal exercise and ejection fraction at rest were not modified, suggesting no major changes in left ventricular function. After unsuccessful coronary bypass surgery, the physical working capacity was unchanged despite an increased maximal heart rate; maximal cardiac output was unchanged and stroke volume during maximal exercise was significantly lower. These undesirable results are often associated with perioperative myocardial infarction and are attended by a decreased ejection fraction at rest; these data suggest an impaired left ventricular function after unsuccessful coronary bypass surgery. The results of partial revascularisation are intermediate but appear to be determined by the incidence of partial graft failure which is also often associated with perioperative myocardial infarction. From individual changes in data collected during maximal exercise testing, it is often impossible to predict the degree of revascularisation.

Experimental Inferior Caval Replacement with Mesothelium

Thrombo-resistance of mesothelial grafts was evaluated by replacing the inferior vena cava in 16 dogs. In 10 dogs, treated by antiplatelet aggregation agents, uniform graft thrombosis happened within 15 days. In six other dogs, the addition of an arterio-venous fistula produced conditions of flow (1385 ± 178 ml/min; mean ± s.e.m.) and velocity (17.1 ± 4.5 cm/s) closer to human values and markedly improved the patency rates (four patent over six up to 6 months P < 0.02). Light microscopy and scanning electron microscopy studies performed on the patent grafts showed well preserved mesothelial cells. Mesothelial fibrinolytic activity was 1160 ± 257 tissue activator units/g tissue before and 846 ± 142 activator units/g tissue after implantation (P = n.s.). Prostaglandin synthesis by native mesothelium was respectively 252 ± 103 and 7 ± 3 pg/ml/mg wet tissue/min for 6-keto-PGF1α and TXB2. The synthesis was reduced for 6-keto-PGF1α in the patent grafts but unaltered for TXB2, This work puts forward the suggestion that mesothelium is a promising venous substitute in conditions of high flow.

Traumatic Rupture of the Thoracic Aorta - a Report of 27 Operated Cases

Twenty-seven cases of traumatic rupture of the thoracic aorta have been operated on in the cardiovascular and thoracic surgery unit at the Catholic University of Louvain: 10 acute ruptures and 17 chronic false aneurysms. The disproportion between the two groups indicates that the acute pathology tends to remain unrecognized, probably because of major associated injuries that can mask the aortic rupture at the time of trauma. To increase the number of cases of acute traumatic rupture of the aorta successfully diagnosed, the diagnosis should be suspected and a routine aortography should be done in every patient who has sustained a high-speed deceleration injury.

Restenosis After Carotid Endarterectomy

Fifty endarterectomies of the internal carotid artery have been performed on 43 patients from March, 1984, to December, 1985. There were no perioperative or hospital deaths. The permeability of the operated vessel was confirmed by Doppler or angiography in every case. All patients received aspirin 100 mg/day and dipyridamole 400 mg/day post operatively and all were examined for follow-up. Routine Doppler examination of the carotid artery was performed at frequent intervals. At long-term follow-up, 4 patients had died. None of these deaths could be linked to a neurologic deficit. Three restenoses due to intimal hyperplasia were discovered at follow-up between the eighth and twelfth months. The three re stenoses were successfully reoperated. Because the risk of carotid artery restenosis appears to be real, routine fol low-up with Doppler examination is required. Suspicion of restenosis is an indi cation for control angiography. If restenosis is severe, a reoperation is warranted.

The Bronchial Carcinoid Adenoma - a Clinical, Radiological and Anatomopathological Study of 25 Operated Patients

SummaryThe goal of this retrospective study is to compare the results of 25 operated cases of bronchial carcinoid adenoma with those published in the literature. If the epidemiological, clinical, laboratory and follow-up results are comparable, our study identifies two unusual aspects of the radiological findings (volume doubling time, cupula sign).In addition, our results confirm the difficulty of a pre-operative anatomopathological diagnosis of the carcinoid tumour, as well as the mediocre contribution of the percutaneous needle aspiration biopsy in peripheral cases.In view of the relatively high number of falsepositive diagnoses of anaplastic small-cell carcinoma in our series, the possibility of an exploratory thoracotomy must be considered.