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Biomedical subjects

J M De Smet

Publications and source records attributed to J M De Smet.

At least 19 recordsLinked to original sources

[The heart surgery department].

The initial development of cardiac surgery at Erasme Hospital was closely related to the achievements in thoracic organ transplantation, with numerous synergies between other clinical and research units of the Faculty of Medicine. New advances in biology and biotechnology have met the challenges of modern cardiology, in the fields of advanced heart failure, refractory angina, rhythm disturbances or minimally invasive surgery. Fundamental aspects of clinical practice have been the subject of laboratory investigations, resulting in fruitful interactions and promising scientific outlooks.

Belgium↗

Conversion from ministernotomy to full sternotomy in aortic valve replacement.

Conversion (C) from ministernotomy (M.S.) to full sternotomy was necessary in 5% of the cases in a series of 100 patients consecutively operated for Aortic Valve Replacement (A.V.R.) Analysis of the demographics and surgical techniques indicate older age, aortic fragility, diffuse coronary disease, chronic renal failure and left vent insertion as contributing factors. Despite increased operative blood losses, extra-corporeal circulation (E.C.C.) times, intensive care unit (I.C.U.) stay and hospital stay, no mortality was observed in the conversion group, as compared to 4.2% mortality in the total ministernotomy (MS) population. Preoperative patients selection, avoidance of technical pitfalls, and knowledge of alternative surgical measures are suggested to further decrease the incidence of conversions.

Aged↗

[Extensive intramural hematoma of the thoracic aorta].

A[TRACE;del] 53-year-old hypertensive patient presenting with acute chest pain was found to have an intramural haematoma (IMH) of both ascending and descending aorta associated with a 6 cm ascending fusiform aortic aneurysm. Six weeks of antihypertensive treatment allowed complete resolution of the intramural haematoma of the descending aorta. Limited surgical repair of the ascending aorta by Gore-Tex graft prosthesis interposition was then performed. The patient was in good health with a one-year follow-up.

Aortic Dissection↗

[Role of transesophageal echocardiography in the diagnosis of pulmonary embolism].

The authors report a 72 year-old woman presenting with severe shock after ilio-femoral artery bypass surgery. The transesophageal echocardiography allowed the diagnosis of an unsuspected massive right pulmonary artery embolism. This case emphasizes the role of this procedure for the early bedside diagnosis of massive pulmonary embolism, especially in critically ill patients who require urgent therapeutic interventions.

Aged↗

Candida albicans septic thrombosis of the right atrium is associated with a central venous catheter.

Right atrial thrombus formation is a rare complication of central venous catheterization in adults. Infection of this thrombus is exceptional. A case of a right atrial thrombus associated with Candida albicans infection is described. Surgical thrombectomy, withdrawal of the catheter, and long-term antiinfectious therapy seem the only appropriate treatment. The literature on this unusual condition is reviewed.

Amphotericin B↗

Prevotella bivia as an unusual cause of endocarditis.

A case of monomicrobial endocarditis due to Prevotella bivia in a 60-year-old man without previous cardiac lesions is reported. The extremely indolent course with multiple systemic emboli as the only clinical manifestation occurring at least seven months before diagnosis and the persistently negative blood cultures were remarkable features of this case. The incidence, clinical characteristics, treatment and outcome of published cases of infective endocarditis due to anaerobic bacteria are briefly reviewed.

Bacteroides↗

Nature of pulmonary hypertension in congestive heart failure. Effects of cardiac transplantation.

Pulmonary hypertension associated with congestive heart failure carries a risk of right ventricular failure after cardiac transplantation. Few data, however, are available on the hemodynamic behavior of the pulmonary circulation in these patients. We therefore studied mean pulmonary artery pressure minus left atrial pressure (estimated by pulmonary artery occluded pressure) versus cardiac output relationships in 20 patients with congestive heart failure evaluated for orthotopic cardiac transplantation, and we repeated this study either within the first 3 days postoperatively (n = 10) or 1 month postoperatively (n = 11). Cardiac output was increased by physical exercise or (in the early postoperative period) by an infusion of dobutamine. Reversibility of pulmonary hypertension was tested by an infusion of prostaglandin E1. At preoperative evaluation, the extrapolated pressure intercept of pulmonary vascular pressure:flow plots was negative in 10 of the patients, suggesting active exercise-induced pulmonary vasoconstriction. In the other 10 patients, the extrapolated pressure intercept was positive, suggesting that an increased closing pressure contributed to pulmonary hypertension. However, transplantation was constantly associated with proportional decreases of pulmonary artery pressure and left atrial pressure. On the other hand, pulmonary vascular pressure:flow plots were displaced to equal or lower pressures and to higher flows by prostaglandin E1 before as well as after transplantation. We conclude that in patients with congestive heart failure evaluated for cardiac transplantation, an increased pulmonary venous pressure more than a reversible increase in closing pressure determines the severity of pulmonary hypertension.

Adolescent↗

Administration of nebivolol after coronary artery bypass in patients with altered left ventricular function.

This prospective, double-blind study used invasive monitoring and echo-Doppler techniques to compare the hemodynamic effects of nebivolol, a new beta 1-selective beta-blocking agent with those of atenolol in patients recovering from coronary artery bypass grafting surgery. Five milligrams nebivolol and 50 mg atenolol equally decreased heart rate (HR) and blood pressure (BP) but, nebivolol, in contrast to atenolol, caused no decrease in stroke index (SI), cardiac index (CI), and right ventricular ejection fraction (RVEF). These differences appeared to be related in part to different peripheral effects of the two agents because nebivolol administration was associated with a reduction in systemic vascular resistance (SVR). After < or = 10 days of treatment, acceleration of aortic flow velocity increased and isovolumic relaxation time decreased with nebivolol but not with atenolol treatment. Both drugs were equally well tolerated. Therefore, nebivolol shares most of its effects with classical beta 1-blockers but is devoid of the potentially harmful effects on cardiac output (CO) and peripheral resistance.

Adrenergic beta-1 Receptor Antagonists↗

PEEP inhibits hypoxic pulmonary vasoconstriction in dogs.

The effects of an increase in alveolar pressure on hypoxic pulmonary vasoconstriction (HPV) have been reported variably. We therefore studied the effects of positive end-expiratory pressure (PEEP) on pulmonary hemodynamics in 13 pentobarbital-anesthetized dogs ventilated alternately in hyperoxia [inspired O2 fraction (FIO2) 0.4] and in hypoxia (FIO2 0.1). In this intact animal model, HPV was defined as the gradient between hypoxic and hyperoxic transmural (tm) mean pulmonary arterial pressure [Ppa(tm)] at any level of cardiac index (Q). Ppa(tm)/Q plots were constructed with mean transmural left atrial pressure [Pla(tm)] kept constant at approximately 6 mmHg (n = 5 dogs), and Ppa(tm)/PEEP plots were constructed with Q kept constant approximately 2.8 l.min-1.m-2 and Pla(tm) kept constant approximately 8 mmHg (n = 8 dogs). Q was manipulated using a femoral arteriovenous bypass and a balloon catheter in the inferior vena cava. Pla(tm) was held constant by a balloon catheter placed by left thoracotomy in the left atrium. Increasing PEEP, from 0 to 12 Torr by 2-Torr increments, at constant Q and Pla(tm), increased Ppa(tm) from 14 +/- 1 (SE) to 19 +/- 1 mmHg in hyperoxia but did not affect Ppa(tm) (from 22 +/- 2 to 23 +/- 1 mmHg) in hypoxia. Both hypoxia and PEEP, at constant Pla(tm), increased Ppa(tm) over the whole range of Q studied, from 1 to 5 l/min, but more at the highest than at the lowest Q and without change in extrapolated pressure intercepts. Adding PEEP to hypoxia did not affect Ppa(tm) at all levels of Q.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Estimating left ventricular filling pressure during positive end-expiratory pressure in humans.

In the critically ill, accurate measurements of left ventricular (LV) filling pressure using pulmonary artery occlusion pressure (Ppao) are important for diagnostic and therapeutic purposes. In patients receiving positive end-expiratory pressure (PEEP), Ppao may not reflect LV filling pressure because of elevated pericardial pressure (Ppc). It has been proposed that in humans, Ppc and right atrial pressure (PRA) are equal, so that referencing Ppao to PRA may improve the assessment of LV filling pressure when Ppc is elevated. Similarly, it has also been shown in the dog that nadir Ppao immediately after airway disconnection from PEEP (nadir Ppao), accurately reflects LV filling pressure when LV filling pressure is greater than or equal to 10 mm Hg. We examined methods of estimating LV filling pressure using Ppao measurements under conditions in which increases in Ppc were the primary determinants of differences in the two measurements. Using left atrial pressure (PLA) relative to Ppc, called transmural PLA (PLAtm), as LV filling pressure, we compared the accuracy of Ppao, nadir Ppao, and Ppao relative to PRA to reflect PLAtm in 15 postoperative cardiac surgery patients in whom an air-filled pericardial balloon catheter and a left atrial catheter were inserted during surgery. PEEP was sequentially increased from zero to 15 cm H2O. We found that PRA always exceeded Ppc (p less than 0.01) and increased less with PEEP than did Ppc (p less than 0.05). At less than or equal to 5 cm H2O PEEP, both Ppao and nadir Ppao were similar to each other and to PLAtm.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

A survey of nine years heart transplantation at Erasme Hospital, University of Brussels.

Between March 1982 and March 1991, 225 heart transplantations (HTx) have been performed in 220 patients suffering end stage cardiac disease. Thirteen percent were females and 87% were males. Age range was from 5 to 68 years. The underlying cardiac disease was ischemic cardiopathy in 51.5%, congestive dilated cardiomyopathy in 42%, valvular cardiomyopathy in 3.5%, toxic myocarditis (post-adriamycin) in 1.5% and chronic rejection in 2.5% (retransplantation). Selection of the recipients was done following the currently well established criteria also taking into account the absolute major contraindications for HTx. Due to the still increasing demand of donor organs, currently donor age has been extended up to 50 years for male and 55 years for female donors. One quarter of the grafts were harvested on site in our institution, two other quarters were harvested somewhere else in Belgium and the last quarter provided by other countries cooperating with Eurotransplant. All patients have undergone orthotopic cardiac transplantation using the standard Lower and Shumway technique. Immunosuppression protocols have changed four times throughout the years. Nevertheless all were based on the use of Ciclosporine variously combined with other current immunosuppressive drugs. Rejection monitoring relied on routine endocardiac biopsy and was diagnosed according to the Billingham criteria. The in-hospital mortality is currently 11%. Infection, early right heart graft failure and acute rejection were the leading causes of death. The major causes of early morbidity were several curable infections, reversible rejection episodes, transient acute renal failure and controllable arterial hypertension. Among the survivors followed for at least one month up to nine years, half of late mortality was caused by chronic rejection followed by infection, sudden death, metabolic disorders, stroke and malignancy. Late morbidity involves cases of mild coronary graft diseases, biological renal insufficiency, some degree of arterial hypertension, dislipidemia. Current actuarial survival rate is 87% at one year, 76% at 5 years up to 9 years. Our experience confirms that HTx represents today and effective therapy for selected patients suffering end stage cardiac disease.

Actuarial Analysis↗

Inhibition of hypoxic pulmonary vasoconstriction by increased left atrial pressure in dogs.

To further explore the mechanism of hypoxic pulmonary vasoconstriction, we studied the mean pulmonary arterial pressure (Ppa)/left atrial pressure (Pla) relationship at fixed cardiac index (Q) and the Ppa/Q relationship at several levels of fixed Pla in pentobarbital sodium-anesthetized dogs ventilated alternately in hyperoxia [fraction of inspired O2 (FIO2) 0.4 or 1.0] and in hypoxia (FIO2 0.1). In all experimental conditions, Ppa/Q plots were linear with extrapolated pressure intercepts (Pi) not significantly different from Pla. Hypoxia increased the slope of Ppa/Q plots and did not affect Pi. In hyperoxia, increasing Pla (3 to 26 mmHg) induced approximately equal increases in Ppa at fixed Q and shifted Ppa/Q plots toward higher pressures in a parallel manner. In hypoxia, increasing Pla (4 to 25 mmHg) did not affect Ppa at fixed Q until Pla exceeded 16 mmHg and shifted Ppa/Q plots toward higher pressures with a decrease in slope. Consequently, the hypoxia-induced increases in Ppa at constant Q and constant Pla were attenuated at higher Pla. Thus, in anesthetized dogs, hypoxia increases the slope of Ppa/Q plots without affecting Pi at fixed Pla, and an increase in Pla inhibits hypoxic pulmonary vasoconstriction. These results can be explained without invoking a hypoxia-induced Starling resistor mechanism in the pulmonary circulation.

Animals↗

[Traumatic rupture of the isthmus of the thoracic aorta (midterm results in a series of 15 cases)].

The authors present a series of 15 cases of traumatic disruption of the aortic isthmus. There were 9 cases of acute rupture and 6 of chronic rupture. All the patients have been operated on. Different technics was used to protect the viscera during aortic cross-clamping, partial E.C.C. in 9 cases, clamp-repair technic in 4 cases and a GOTT shunt in 2 cases. 4 patients died in the first thirty days (3 acute and 1 chronic). 2 cases of paraplegia was observed. All the patients have been reviewed after a mean follow-up of 36 months and remain well but one who is still paraplegic. Surgical repair is mandatory in acute and aortic disruption with a great attention to the associated injuries.

Accidents, Traffic↗

Absence of cardio-depressant effects of CGP 17582 B, a new beta-blocking agent, in patients after coronary surgery.

The hemodynamic effects of CGP 17582 B, a new cardio-selective beta-blocking agent with moderate intrinsic sympathomimetic activity and minimal effects on myocardial contractility, were studied in patients after cardiac surgery for coronary artery bypass graft. Each patient had been treated preoperatively with beta-blocking agents and had a cineangiographic left ventricular ejection fraction between 40 and 60%. Fourteen patients were randomized to receive either 10 mg of propranolol or 50 mg of CGP 17582 B orally. Both drugs resulted in a significant and a similar decrease in heart rate. However, this was associated with a significant decrease in stroke volume after propranolol but not after CGP 17582 B, so that cardiac output significantly decreased only after propranolol. Thermodilution right ventricular ejection fraction significantly decreased after propranolol but not after CGP 17582 B. Each drug was well tolerated during the 10 following days and the recovery was uneventful in each patient. These results indicate that CGP 17582 B is a promising beta-blocking agent susceptible to reduce heart rate without altering cardiovascular function after cardiac surgery.

Adrenergic beta-Antagonists↗

[Functional non-invasive cardio-respiratory evaluation a month and a year after orthotopic heart transplantation].

Cardio-respiratory stress tests of 14 patients, performed one month and one year after orthotopic heart transplant, are compared in order to demonstrate the functional and metabolic improvements of their adaptation to stress. At maximal stress, we note a 33 p. cent increase of the oxygen consumption (p 0.001), an 11 p. cent increase of the heart rate (p 0.025) and an 18 p. cent increase of the systolic arterial pressure (p 0.005). Respiratory quotients and respiratory equivalent for oxygen are significantly lower (p 0.008) while there was no significant variation of ventilation/minute, respiratory rate, and the normal capacity. At the sub-maximal level, the only significant differences observed are the decrease of the respiratory quotient (p 0.01), the ventilation/minute (p 0.025), the respiratory equivalent for oxygen (p 0.005) and the respiratory rate (p 0.03). The improvement of the physical condition observed in heart transplants seems related to a better peripheral adaptation to stress (lower respiratory quotients, reflection of the decreased demand on anaerobic metabolism) permitting a lesser demand on the ventilatory response to stress.

Adult↗