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Biomedical subjects

P Sergeant

Publications and source records attributed to P Sergeant.

At least 55 records · Page 3Linked to original sources
PubMed1990

Internal mammary artery: methods of use and their effect on survival after coronary bypass surgery.

Hazard analysis of total and cardiac mortality after isolated primary coronary artery surgery was performed using univariate and multivariate methods with special emphasis on the importance of the use and method of use of the internal mammary artery (IMA) as a bypass graft. The clinical data of 5880 consecutive patients were studied. The sum of the real follow-up periods studied was 27,948 years. The hazard of total and cardiac mortality could be defined in three-phase parametric models with an early, a constant and a late phase. The total survival was 82% +/- 1% at 10 years and 59% +/- 3.6% at 15 years. The construction of a single IMA distal graft (using left or right IMA) had a positive influence on the hazard (P = 0.0004) in the late phase after surgery with a high estimate (-1.6). The cardiac survival was 89% +/- 0.8% at 10 years and 74% +/- 3.5% at 15 years. The use of the left IMA had a positive influence (P = 0.001) in the late phase after surgery with a very high estimate (-2.3). The generated simulation of the total survival of a median patient with an IMA graft is 97% at 5 years and 94% at 10 years; for a median patient without an IMA graft, it is 97% at 5 years and 88% at 10 years. If a patient has other risk factors reducing his life expectancy, the influence can be dissipated because of lower survival rates at 5 years after surgery, when the effect of the IMA becomes most apparent.(ABSTRACT TRUNCATED AT 250 WORDS)

Belgium↗
PubMed1987

The value of ejection fraction as a predictor of early and late survival following aortocoronary bypass surgery in patients with moderate to severe depression of the left ventricular function.

Predictability analysis of early and late survival of coronary bypass patients with reduced left ventricular function was performed using stepwise logistic regression based on preoperative and operative data. The total perioperative mortality was 3.4% and the total actuarial survival of the whole group at 42 months was 87.7%. Thirty preoperative and operative parameters of 149 patients were entered into a first mathematical model. Four parameters were selected as a consequence: ejection fraction, anginal class, obesity, septal infarct. A prediction model based on these parameters, gave a correct prediction of the operative outcome in 99.3% of the patients. However due to the only five perioperative deaths, this model should be interpreted with caution. The accuracy of ejection fraction alone was 97.3%, the sensitivity was 100% but the specificity was only 20%. The same parameters of 97 patients were entered into a second mathematical model. Four parameters were selected in this case: ejection fraction, NYHA functional classification, septal infarct, anterior infarct. A second prediction model, based on these parameters, gave a correct prediction of the late outcome at 24 months in 93.8% of the patients. The accuracy of the discrimination on the basis of ejection fraction alone was 89.7%, its sensitivity was 96.5% but its specificity was only 41.7%. Ejection fraction was the best predictor out of the studied variables but due to its low specificity not good enough as a sole parameter.

Adult↗
PubMed1987

Emergency coronary bypass grafting for evolving myocardial infarction. Effects on infarct size and left ventricular function.

Emergency aorta-coronary bypass grafting was performed early in the course of evolving myocardial infarction in 48 patients. The time interval between the onset of symptoms and reperfusion was 169 +/- 80 minutes. Quantitative assessment of postoperative thallium 201 myocardial scans in 19 patients revealed a significant salvage of myocardium after surgical reperfusion: The size of the residual infarction was less than 50% of that in a matched, medically treated, prospective control group (n = 39) (p less than 0.05). Postoperative equilibrium-gated radionuclide blood pool studies (technetium 99m) showed an enhanced recovery of regional and global ejection fraction after operation as compared to after medical treatment (p less than 0.05). Ultrastructural evaluation of biopsy specimens obtained during the operation delineated subendocardial necrosis in the majority of cases (72%), but subepicardial necrosis was found in only 6% of instances. Q-wave abnormalities were observed on the postoperative electrocardiogram in 50% of cases. Operative mortality was 0% in low-risk patients (i.e., hemodynamically stable condition, n = 26) and 18% in high-risk patients (i.e., cardiogenic shock including total electromechanical dysfunction, n = 22). Survival rate at 18 months was 92% +/- 4%, and 95% +/- 4% of the survivors were event free. It is concluded that early surgical reperfusion of evolving myocardial infarction limits infarct size significantly, enhances functional recovery, and may be a lifesaving operation in patients having cardiogenic shock associated with unsuccessful resuscitation.

Actuarial Analysis↗
PubMed1986

How predictable is the postoperative work resumption after aortocoronary bypass surgery?

The number of aortocoronary bypass procedures increased at the Cardiovascular Surgery Department of the University Hospital in Leuven (Belgium) from 12 patients in 1971 to 650 patients in 1983. A similar evolution took place in the other existing Belgian cardiovascular centers and new departments were created to fill this need. The financial burden of the direct hospital costs of these procedures on the National Health Care program is considerable. The postoperative work-resumption will restore the patient's social dignity, it can increase the patient's personal income and thus decrease the indirect costs such as workmen's compensation; it will therefore improve the cost effectiveness of coronary surgery so that it can be offered to the numerous patients who need it for their survival or for the improvement of their quality of life. Studies about the employment status before and after aortocoronary surgery, as published from other centers, can not be projected on the Belgian situation due to the difference in population cohorts, laws regulating the working conditions, the national unemployment ratio and disability compensations. With this in mind, a study of the preoperative and postoperative employment and its predictability was undertaken.

Adult↗
PubMed1986

Nifedipine as an adjunct to St. Thomas' Hospital cardioplegia. A double-blind, placebo-controlled, randomized clinical trial.

The cardioprotective effect of the addition of the slow calcium-channel blocker nifedipine to cardioplegic solution was tested in two double-blind placebo controlled randomized studies. The first study included 24 patients undergoing aortic-coronary bypass grafting, and the second included 24 patients undergoing aortic valve replacement. Nifedipine at a dose of 200 micrograms/L or placebo was added to St. Thomas' Hospital cardioplegic solution. The following markers of ischemia were used: adenosine triphosphate and its catabolites, creatine phosphate and inorganic phosphate, determined in transmural left ventricular biopsy specimens taken before, at the end of, and after aortic cross-clamping; hemodynamic recovery 15 minutes after cessation of cardiopulmonary bypass; clinical outcome in terms of the incidence of arrhythmias, low cardiac output, positive inotropic support immediately after operation, and follow-up at 15 months. The main difference between the two studies was that myocardial temperature during cross-clamping remained constant at 14 degrees C in coronary bypass grafting but increased to 25 degrees C in valve operations despite the application of the same amounts of cardioplegic solutions. This lower temperature resulted in better preservation of high-energy phosphates in coronary bypass operations as compared to the placebo group having valve replacement operations. According to analysis of variance, a drug effect could be demonstrated only in the aortic valve replacement study: Accumulation of breakdown products of the adenine nucleotide pool was less in the nifedipine group than in the placebo group (p less than 0.05). Adenosine triphosphate decreased only to 84% in the nifedipine group and to 72% in the placebo group. Despite this adenosine triphosphate-sparing effect, weaning from cardiopulmonary bypass was more difficult in the nifedipine group. Left ventricular stroke work index 15 minutes after bypass was decreased to 72% of the prebypass value in the nifedipine group (t test, p less than 0.01) and only to 86% in the placebo group (p = NS). In contrast, after the patients were admitted to the intensive care unit, the incidence of low cardiac output tended to be lower in the nifedipine group than in the placebo group: 33% versus 58% (p = NS). In conclusion, ischemia-induced degradation of nucleotides as it occurs when myocardial cooling is inadequate can be prevented by the addition of nifedipine to the St. Thomas' Hospital cardioplegic solution. This effect, however, is not associated with an improved clinical outcome.

Adult↗
PubMed1985

Emergency bypass surgery: late effects on size of infarction and ventricular function.

Using thallium myocardial scintigraphy and radionuclide ventriculography, we assessed size of infarction and left ventricular function at late follow-up (greater than 2 months) in 13 patients who underwent emergency coronary artery bypass surgery (ECABS) during evolving myocardial infarction and in 26 controls who received conventional treatment for acute infarction. Thallium scans were quantitatively analyzed. The thallium defect, expressed as a numerical value in arbitrary units, was smaller after early revascularization (within 4 hr of the onset of symptoms, n = 10) than in the controls: 397 +/- 232 vs 2779 +/- 972 for anterior infarction (p less than .001) and 475 +/- 511 vs 1454 +/- 960 for inferior infarction (p less than .05). The patients undergoing revascularization late (4 to 5 hr after the onset of symptoms, n = 3) had thallium defects comparable to those in the controls. Regional ejection fraction of the involved left ventricular segment was higher after early revascularization (41 +/- 9% vs 21 +/- 8% for anterior infarction, p less than .005; 67 +/- 14% vs 51 +/- 11% for inferior infarction, p less than .01). Global ejection fraction was higher after early revascularization in patients with anterior infarction (57 +/- 10% vs 37 +/- 9%, p less than 0.02), but not in those with inferior infarction (60 +/- 11% vs 54 +/- 8%, p greater than .05). After late revascularization, regional and global ejection fraction were comparable to those in controls. In selected patients, early reperfusion of acutely ischemic myocardium by ECABS can limit size of infarction and preserve left ventricular function, but time constraints may be severe.

Adult↗
PubMed1984

Multivariate analysis of angiographic, histologic, and electrocardiographic data in patients with coronary heart disease.

In 61 consecutive patients undergoing aortocoronary bypass grafting, angiographic and electrocardiographic (ECG) changes were studied. Histologic delineation of myocardium was obtained by analysis of transmural biopsy specimens acquired at the time of surgery. The use of principal-component analysis revealed three definite groups of patients. Group I comprised patients with histologic findings associated with severe left anterior descending coronary artery (LAD) stenosis, without abnormal wall motion or ejection fraction. ECG abnormalities were limited to ST changes. Group II comprised patients with severe myocardial cell degeneration with only modest fibrosis associated with severe LAD stenosis and severely impaired wall motion. The incidence of infarction on the ECG was low. Group III patients had important myocardial cell degeneration with severe fibrosis associated with severe LAD stenosis, severely depressed wall motion, and significantly impaired ejection fraction. In this group there was a high incidence of infarction apparent on the ECG. Postoperative follow-up (24 months) showed a total survival of 94.4% in group I, 92.8% in group II, and only 72.7% in group III. This identification of subtypes of coronary artery disease seems to be helpful in estimating patient prognosis after coronary surgery.

Adult↗
PubMed1984

Intermittent aortic cross-clamping versus St. Thomas' Hospital cardioplegia in extensive aorta-coronary bypass grafting. A randomized clinical study.

Myocardial preservation was assessed in 72 patients undergoing extensive myocardial revascularization. The patients were allocated at random to three surgical techniques: Group 1, intermittent aortic cross-clamping at 32 degrees C; Group 2, intermittent aortic cross-clamping at 25 degrees C; and Group 3, St. Thomas' Hospital cardioplegia. As intraoperative markers of ischemic damage, adenosine triphosphate, creatine phosphate, and glycogen contents were determined in transmural left ventricular biopsy specimens taken at the beginning and at the end of cardiopulmonary bypass. Ultrastructure was studied in a similar pair of biopsy specimens. Release of myocardium-specific creatine kinase isoenzyme was determined intraoperatively and postoperatively. Functional recovery was assessed before and after weaning from cardiopulmonary bypass. The incidence of low cardiac output, myocardial infarction, and rhythm disturbances was compared between groups. Finally, actuarial survival and event-free curves were studied after 18 months' follow-up. The results show a better preservation of high-energy phosphates, glycogen, and ultrastructure in the cardioplegia group as compared to the two cross-clamp groups. However, severe myocardial damage was never observed. Release of MB creatine kinase isoenzyme was the same in all three groups. Functional recovery of the hearts immediately after cessation of cardiopulmonary bypass was better in the cardioplegia group, but the incidence of rhythm disturbances (atrioventricular conduction problems) was higher in the cardioplegia group than in the other two groups (p less than 0.05). Clinical outcome in terms of incidence of perioperative infarction, survival, and event-free follow-up was not different between groups. It is concluded that both techniques (aortic cross-clamping at 32 degrees C or 25 degrees C and St. Thomas' Hospital cardioplegia) offer good myocardial protection in extensive aorta-coronary bypass operations. St. Thomas' cardioplegia, however, in contrast to intermittent aortic cross-clamping, prevents the onset of ischemia-induced deterioration of cardiac metabolism, i.e., destruction of the adenine nucleotide pool.

Adenosine Triphosphate↗
PubMedDate not supplied

Cardiac perforation after Kirschner wire migration.

A case report is described in which a patient developed cardiac tamponade after migration of a Kirschner wire, used for fixation of a luxated sternoclavicular joint, through the pericardium and into the pulmonary artery.

Bone Wires↗
PubMedDate not supplied

Combined myocardial and cerebral revascularization. A ten year experience.

We report on the results of combined carotid endarterectomy and coronary artery bypass grafting in 82 patients. Vascular pathology was severe in these cases: 94% of patients had extensive multivessel coronary artery disease, 29% had unstable angina, 30% had severe left main stem stenosis and all patients had hemodynamically significant stenosis of at least one carotid artery, 13% had an additional occlusion of the contralateral internal or common carotid artery and 26% had severe bilateral carotid artery stenosis. The carotid lesion was asymptomatic in 64% of cases, 24% of the patients experienced previous transient cerebral ischemia and 12% of the patients had a history of completed stroke. Hospital mortality was 7.3%. Neurological deficit occurred in 7.3% but functional impairment was not permanent. Late results have been obtained for 76 survivors at a mean postoperative interval of 29 months. Five year life table survival rate was 86%. Follow-up showed that 3 patients (4%) have died and that 3 patients (4%) experienced a late neurologic event (one TIA; two strokes) but none of these events involved the cerebral cortex on the side of the carotid endarterectomy. The cumulative 5 year stroke free survival rate is 91%. We conclude that combined carotid endarterectomy and coronary artery bypass grafting can be done with an acceptable mortality rate in these critically ill patients and that the postoperative incidence of neurological events is low.

Adult↗
PubMedDate not supplied

The sequential internal mammary artery graft. Long term results of a consecutive series of 364 patients.

Sequential, bilateral and free mammary grafts are employed in the current operative treatment of coronary pathology to maximize the benefit of the enhanced long-term patency of the internal mammary graft. This study reports the early and late results of a consecutive series of 364 patients in whom an internal mammary artery jumpgraft was performed. The total perioperative mortality was 1.6%, the cardiac perioperative mortality 1.0%. The perioperative infarct rate was 2.5%; the infarct rate in the mammary outflow field 1.4%. The total survival at 90 months (operative mortality included) was 92.2%, the cardiac survival at 90 months was 95.8% and the event-free group of the operative survivors was 85.2% at 90 months. The mammary artery jumpgraft can be performed without additional risk to the patient, it has a very good late result and it should be standard tool in the current coronary surgery technique. It is essential in coronary redo surgery and in patients after bilateral saphenectomy.

Female↗
PubMedDate not supplied

Is the outcome of coronary artery bypass graft surgery predictable in patients with severe ventricular function impairment?

Sixty consecutive patients, with a mean ejection fraction of 31.8% underwent coronary revascularization at the K. U. Leuven (Belgium). The operative mortality was 6%. At twelve months after surgery, the total actuarial survival was 90.0%, at twenty four months the total survival was down to 77.9%. All the preoperative data were entered into a mathematical model and using the stepwise logistic regression method, the predictability of death at 18 months postoperatively was analyzed. Using only the ejection fraction the accuracy of the prediction was 83.3%, the sensitivity 36.4% and the specificity 93.9%. Combining ejection fraction and NYHA functional classification before surgery the accuracy increased to 91.7%, the sensitivity to 72.7% and the specificity to 95.9%. Ejection fraction alone is a poor predictor of late death with only 36.4% sensitivity, but combining it with other parameters it is possible to construct a formula predicting death at 18 months with an accuracy of 91.7%.

Actuarial Analysis↗
PubMedDate not supplied

Time constraints in the emergency coronary bypass surgery for acute evolving myocardial infarction.

Fourty four patients underwent emergency coronary grafting for evolving myocardial infarction. All patients but one had undergone coronary angiography before the new infarction, 50% were in cardiogenic shock or under cardiopulmonary resuscitation. The mean time interval between the onset symptoms and opening of the bypass to the threatened area was 171 minutes. The operative mortality was 6.8%. At 30 months after surgery, the cardiac actuarial survival was 93.2%, the angina free group 94.2% of the operative survivors. Infarct size and regional ejection fraction of these patients at late follow-up were compared to those of controls treated conventionally for acute infarction. The thallium defects were smaller and the regional ejection fraction of the involved segment was higher after early surgery (less than 3 hours ischemia) than in controls. In the late surgery group the thallium defects and the regional ejection fractions were similar. Ultrastructural studies on biopsy samples taken from the center of the threatened area show reversible changes in the early surgery group but irreversible mitochondrial damage and cell membrane rupture in the late surgery group. Biochemical analysis of similar cardiac biopsies shows recovery after one hour empty beating reperfusion but only in the early surgery group. Our results suggest that coronary surgery can be beneficial to the patient with an evolving myocardial infarction, if the clinical situation does not permit intracoronary thrombolysis. However, one hour reperfusion of the empty beating heart before weaning off bypass is essential. The time constraints for both emergency surgery or thrombolysis are similar.

Adult↗
PubMedDate not supplied

Surgical treatment of acute, massive lung embolism. Results and follow-up.

Between 1970 and 1984 the diagnosis of acute, massive lung embolism was made 30 times in our department. In 29 patients the clinical diagnosis was correct and a Trendelenburg operation under extra-corporeal circulation was performed. In 18 cases there was an operation in the immediate preoperative course. In 1 case there was a combination of operation and the use of contraceptives. 3 cases were immobilized by a plaster of Paris cast. In 4 cases the use of oral contraceptives and in 3 patients the history of chronic recurrent lung embolism were evident. The mean immobilisation time was 15 days. In 24 cases the diagnosis was made only on the base of the clinical anamnesis, and examination, E.C.G. and chest radiography. In 4 cases angiography and in 1 patient the scintigraphy confirmed the diagnosis. Preoperatively 28 patients were in severe shock. One patient was operated electively. 14 patients needed external cardiac massage. In all cases clots were found in the left pulmonary artery, 28 in the right pulmonary artery, in 3 cases clots in the right atrium, 3 in the right ventricle and three in the inferior caval vein. Nine De Weese caval vein clips were inserted and one Mobin-Uddin filter. Postoperatively 18 patients were alive and well without sequelae. Two patients developed a cerebro-vascular accident (CVA) with one complete recovery. Ten patients died. Postoperative treatment consisted of I.V. heparin administration immediately after surgery and 6 months of oral anticoagulants. Except for chronic recurrent lung embolism the pulmonary function tests were excellent postoperatively without recurrence of the disease.

Acute Disease↗