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Biomedical subjects

R Jenni

Publications and source records attributed to R Jenni.

At least 73 records · Page 4Linked to original sources
PubMed1999

Outcome of pregnancy in women with congenital shunt lesions.

OBJECTIVE: To evaluate the outcome of pregnancy in women with congenital shunt lesions. SETTING: Retrospective study in a tertiary care centre. METHODS: Pregnancy history was obtained by a standardised questionnaire and medical records were reviewed. PATIENTS: 175 women were identified, at a mean (SD) age of 42 (14) years. Pregnancies occurred in 126 women: 50 with an atrial septal defect, 22 with a ventricular septal defect, 22 with an atrioventricular septal defect, 19 with tetralogy of Fallot, and 13 with other complex shunt lesions. RESULTS: 309 pregnancies were reported by 126 woman (2.5 (1.6) pregnancies per woman). The shortening fraction of the systemic ventricle was 40 (8)%, and 98% were in New York Heart Association class I-II at last follow up. Spontaneous abortions occurred in 17% of pregnancies (abortion rate, 0.4 (0.9) per woman). Gestational age of the 241 newborn infants was 8.8 (0.8) months. There were no maternal deaths related to pregnancy. Pre-eclampsia and embolic events were observed in 1.3% and 0.6%, respectively of all pregnancies. Women with complex shunt lesions more often underwent caesarean section (70% v 15-30%, p = 0.005) and gave birth to smaller babies for equivalent gestation (2577 (671) g v 3016 (572) to 3207 (610) g, p < 0.05). The recurrence risk of congenital heart disease was 2.5%. CONCLUSIONS: The outcome of pregnancy is favourable in women with congenital shunt lesions if their functional class and their systolic ventricular function are good. Such patients can be reassured.

Abortion, Spontaneous↗
PubMed1999

Pregnancy after atrial repair for transposition of the great arteries.

OBJECTIVE: To investigate the risk of pregnancy in patients with transposition of the great arteries (TGA) who have undergone atrial repair. DESIGN: Retrospective analysis (1962-94) of 342 TGA patients who underwent atrial repair. Of 231 known late survivors, 48 were women over 18 years old who were interviewed about possible reproductive plans and previous pregnancies. As a control, comparison was made with data of 57 500 women (mean age 26 years) obtained from the Swiss Statistical Bank in Bern. RESULTS: Mean follow up was 13.7 years; 66% remained asymptomatic, 29% had mild to moderate cardiac symptoms, and 5% suffered from severe cardiac symptoms (New York Heart Association grade III-IV). Thirty six of the 48 women wished to bear children and, to date, there have been 10 live births, two spontaneous first trimester abortions, and one induced abortion at 16 weeks. During pregnancy there was one case of cardiac deterioration and two cases of pneumonia. There was no evidence of congenital heart disease in the children. CONCLUSIONS: In this relatively small series the completion of pregnancy in women with TGA who had undergone atrial repair and who had normal functional cardiac status was uncomplicated

Abortion, Spontaneous↗
PubMed1999

Long term follow up of prosthetic valve endocarditis: what characteristics identify patients who were treated successfully with antibiotics alone?

OBJECTIVE: To identify predictors for the safe use of antibiotic treatment without reoperation in patients with prosthetic valve endocarditis. SETTING: Retrospective study in a tertiary care centre. SUBJECTS AND DESIGN: All 49 episodes of definite prosthetic valve endocarditis (Duke criteria) diagnosed at one institution between 1980 to 1997 were analysed. Ten episodes (20%) were treated with antibiotics only (antibiotic group) and 39 episodes (80%) with combined antibiotic and surgical treatment (surgery group). The analysis included detailed study of hospital records and data on long term follow up which were obtained in all patients by a questionnaire or telephone contact with physician or patient. The length of follow up (mean (SD)) was 41 (32) months in the antibiotic group and 45 (24) months in the surgery group (NS). Long term survival was estimated by the Kaplan-Meier method and compared by the log-rank test. RESULTS: There was no significant difference in age, history of previous endocarditis, number of previous heart operations, vegetations, emboli, type of prosthesis, or percentage of early prosthetic valve endocarditis and positive blood cultures between the two groups. In the antibiotic group, there were more enterococcal (50%; p = 0.005) and in the surgery group more staphylococcal infections (55%; p = 0.048). Annular abscesses (p < 0. 0001) and aortoventricular dehiscence (p = 0.02) were more common in the surgery group. No patient in the antibiotic group had heart failure. Long term follow up showed no significant difference between the surgery and antibiotic groups regarding late mortality (14% v 18%) and five year rates of recurrent endocarditis (14% v 16%), event related mortality (14% v 3%, log-rank test), and the need for reoperation (14% v 19%; log-rank test). The only patient with conservatively treated staphylococcal prosthetic valve endocarditis died after reoperation for recurrence. CONCLUSIONS: Haemodynamically stable patients with non-staphylococcal prosthetic valve endocarditis who are carefully supervised can be treated with antibiotics alone without an increased rate of reinfection, reoperation, or death.

Adolescent↗
PubMed1999

Optimized performance of the Abiomed BVS 5000: adjustment of the pump height based on Doppler control of the flow pattern.

The Abiomed BVS 5000 is an automatic volume-driven paracorporeal pulsatile assist device providing left, right or biventricular support. The paracorporeal position allows optical adjustment of filling volumes of the device, which determines the output of the system. A procedure to adjust for maximal stable flow has not yet been established. In vitro measurements have been performed to assess the flow and pressure characteristics of the Abiomed BVS 5000 by raising the preload in 5 mmHg steps before running the system. Doppler probes were placed at the inflow and outflow lines of the pump. After setting the afterload at 80 mmHg the assist device was started. Two measurements were performed to find optimal flow (based on Doppler control and optical adjustment). (1) By Doppler control a stable flow pattern was found at a preload of 25 mmHg with a mean atrial pressure of 5 mmHg and a mean flow of 5.3 +/- 0.7 l/min (mean +/- standard deviation) at the inflow and outflow sites (the console flow was 4.8 +/- 0.4 l/min with a frequency of 61.8 +/- 2.0 l/min). (2) Optical adjustment of the pump height gave rise to a preload of 35 mmHg where we recorded a maximal atrial pressure of 107 +/- 5.8 mmHg, a maximal retrograde flow of -4.3 +/- 1.2 l/min at the inflow and -1.2 +/- 0.4 l/min at the outflow site. The mean flow at the inflow and outflow sites was 5.1 +/- 0.5 l/min (the console flow was 4.6 +/- 0.3 l/min with a frequency of 59.6 +/- 2.6 Hz). At an initial afterload of 60 and 40 mmHg the system showed the same qualitative behaviour, but the results were less accurate. Optical adjustment of the pump height may result in an atrioventricular valve insufficiency with undetected retrograde flow and high atrial pressures. We conclude that a Doppler flow probe must be placed at the inflow site to guarantee maximal stable flow.

Equipment Design↗
PubMed1998

[Echocardiography: indications].

Echocardiography is the most important non-invasive test for many cardiovascular diseases. Morphologic and haemodynamic evaluation can be performed in a short time. In this review we will discuss the most common and the most important indications for an echocardiographic assessment. A detailed list for a quick reference is included at the end.

Echocardiography↗
PubMed1998

Sequence of the putative alanine racemase operon in Staphylococcus aureus: insertional interruption of this operon reduces D-alanine substitution of lipoteichoic acid and autolysis.

A gene cluster comprising the alanine racemase gene alr was identified 5' to the sigB operon in Staphylococcus aureus. It is flanked upstream by four ORFs of which one shows similarity to the dpj gene of Escherichia coli, and downstream by two ORFs of which the last shows similarity to the E. coli pemK gene. Preliminary data suggest that the seven ORFs orf1-orf2-orf3-dpj-alr-orf6-pemK may form an operon. Disruption of the proposed operon by insertional mutagenesis leads to a drastic loss in the d-alanine (d-Ala) substitution of lipoteichoic acid and to delayed autolysis, without affecting the d-Ala substitution of the wall teichoic acid.

Alanine↗
PubMed1998

Prognosis of medically treated patients referred for cardiac transplantation.

OBJECTIVES: To assess prognosis and factors influencing survival of transplant candidates in whom continued medial therapy was recommended in comparison to that of immediately listed patients. METHODS: Retrospective analysis of clinical, echocardiographic and hemodynamic data as related to survival or listing for transplantation of medically treated transplant candidates. PATIENTS: 160 patients considered 'too well' for cardiac transplantation and 133 patients immediately listed for transplantation. RESULTS: Forty-one of the medically treated patients deteriorated clinically and were listed after 10.7+/-12.3 months after initial evaluation. Mid-term prognosis (2 years) of patients never listed was comparable to that of immediately listed patients (74% vs. 70%) but long-term prognosis (5 years) was worse (41% vs. 54%, p<0.001). Cardiothoracic ratio and pulmonary capillary wedge pressure were independent predictors of survival (multivariate analysis) in patients whose NYHA class and physical working capacity improved and cardiothoracic ratio decreased significantly after adjustment of medical therapy. CONCLUSIONS: Mid-term prognosis of selected patients considered 'too well' for transplantation is comparable to patients immediately listed. Lower left ventricular filling pressures, smaller hearts on chest X-ray on initial evaluation, and improvement of symptoms during follow up may identify a subgroup of patients who do well on optimized therapy.

Actuarial Analysis↗
PubMed1998

Position control of intravascular Doppler guidewire: concept of a tracking indicator and its clinical implications.

Intracoronary Doppler ultrasound guidewires (DGW) utilize a wide ultrasound beam combined with a measurement of the spectral peak velocity to estimate the spatial peak velocity within a blood vessel. However, the spectral peak velocity may underestimate the true spatial peak velocity if the DGW is not properly positioned. The purpose of this study was to find a Doppler-derived parameter that would aid in the optimal positioning of the DGW within the vessel lumen. We studied the relationship between the time-averaged, spectral-peak velocity (APV) and the normalized first Doppler moment (M1/M0) to develop a DGW position indicator and demonstrate its clinical utility. In vitro, heparinized, human whole blood with a hematocrit of 45% was directed from a reservoir via a roller pump into four serially connected straight silicone tubes of known diameter (2.5, 3.0, 3.5, 4.0 mm). A DGW was inserted into the tubes where simultaneous APV and M1/M0 measurements were obtained for flow rates ranging from 49 to 316 ml/min. Optimal positioning of the DGW was identified at the position where maximum APV and M1/M0 were obtained. With optimal positioning the correlation between APV and M1/M0 was good (APV = 1.62 M1/M0 + 5.0; R2 = 0.98). Importantly, this correlation showed no dependence on the tube diameter. In vivo, in four patients APV and M1/M0 measurements were obtained in 16 coronary artery segments in one left anterior descending, two circumflex, and two right coronary arteries. In 10 vessel segments, there was no discrepancy between the measured and expected M1/M0 after positioning the DGW with help of the Doppler signal quality only. In six vessel segments, repeat DGW positioning using M1/M0 was necessary, yielding an average increase of APV of 20% (7-38%). We conclude that DGW positioning can be optimized using the correlation between APV and M1/M0 as a reference. For any given APV value, there is a corresponding expected value for M1/M0 under the condition of optimal positioning. Any discrepancy between the measured and expected values for M1/M0 then indicates suboptimal positioning.

Blood Flow Velocity↗
PubMed1998

Impact of Doppler guidewire size and flow rates on intravascular velocity profiles.

Coronary blood flow velocity measurements by conventional intravascular catheter-based Doppler devices are well known to be affected by catheter size. Moreover, it is of clinical importance that the assessment of maximum vasodilator capacity, i.e., the coronary reserve, might be considerably affected by a shape change of the velocity profile under hyperemia. Therefore, the present in vitro study aimed to assess the impact of a small-size Doppler guidewire on the velocity profiles interrogated in tubes with diameters corresponding to the epicardial coronary arteries at clinically relevant flow rates. A 0.014" guidewire was inserted into four serially connected silicone tubes of known diameter, which were perfused with discarded human whole blood by means of a roller pump. In order to determine the effect of the Doppler guidewire on the velocity profile antegrade and retrograde perfusion were carried out in each vessel segment. Vm, the true mean velocity, was calculated from the time collected flow divided by the corresponding vessel cross-sectional area. Average peak velocity (APV) measurements were obtained by pulling back the Doppler device across each of the four vessel segments with given flow rates ranging from 1.14-5.88 ml/s in antegrade and retrograde direction. The shape factor of the recorded velocity profile (fp) is defined as vm/APV and is generally assumed to be close to 0.5. Antegrade perfusion: APV = 1.63 vm + 5.35 (R2 = 0.98); fp = 0.001 vm + 0.51. Retrograde perfusion: APV = 1.71 vm + 3.33 (R2 = 0.98); fp = 0.001 vm + 0.52. Due to the constant relationship between APV and vm, velocity profiles within vessels of epicardial coronary artery size are not substantially disturbed by the presence of the Doppler guidewire. The slight, but significant increase of experimental fp with increasing flow is at variance with the theoretically expected fp values.

Blood Flow Velocity↗
PubMed1998

Teichoic acid content in different lineages of Staphylococcus aureus NCTC8325.

A series of mec transformants of Staphylococcus aureus strain NCTC8325 were analysed for alterations in wall teichoic acid and lipoteichoic acid. Although the methicillin resistance determinant alters the autolytic behaviour of S. aureus, it had no effects on the cellular content, chain length, and alanine substitution of the lipoteichoic acid, or on the wall teichoic acid content and composition. However, independently of the presence or absence of the methicillin resistance determinant, level of methicillin resistance, or autolytic behaviour, a correlation was found between a 25% reduced cell wall phosphate content and either loss of prophages phi11 and 13 or a 30-kb deletion in the chomosmal SmaI-F fragment adjacent to the prophage &phi;11 attachment site.

Acetylglucosamine↗
PubMed1998

[Cor triatriatum dexter of an adult].

Cor triatriatum dexter is a rare congenital malformation in which a membrane divides the right atrium into two chambers. The membrane represents a persistence of the right sinus venosus valve (RSV). Normally the RSV regresses between the 9th and 15th week of gestation, as the cephalic portion forms the crista terminalis and the caudal portion develops into the Eustachian and Thebesian valve. Any failure in the regression process may result in remnants of RSV as a simple muscle bar, a Chiari-network or a fenestrated or unfenestrated membrane (cor triatriatum dexter). We describe a patient with cor triatriatum dexter in whom diagnosis was made several years after successful valvulotomy procedure for severe congenital valvular pulmonary stenosis.

Adult↗
PubMed1998

Inflammatory aneurysm of the ascending aorta.

The gold standard to clarify an acute pathology of the ascending aorta is transesophageal echocardiography or contrast-enhanced computed tomography. Neither of these methods led to the correct finding in our case of an inflammatory aneurysm of the ascending aorta. Both assessments resulted in the diagnosis of an acute dissection of the ascending aorta.

Aortic Dissection↗
PubMed1998

Long-term follow-up in hypertrophic obstructive cardiomyopathy after septal myectomy.

BACKGROUND: Controversy exists about the choice of treatment for patients with hypertrophic obstructive cardiomyopathy. The purpose of this study was to evaluate clinical and echocardiographic long-term results in patients with hypertrophic obstructive cardiomyopathy after septal myectomy and to determine predictors of event-free survival in these patients. METHODS: Between 1965 and 1995, 110 consecutive patients 2 to 66 years old (mean age, 37 +/- 15 years) with an invasively measured left ventricular outflow tract gradient of 86 +/- 39 mm Hg (81 +/- 42 mm Hg by Doppler echocardiography) underwent either septal myectomy only (n = 87) or myectomy combined with additional procedures (n = 23). Mean follow-up was 11.7 +/- 7.5 years. Predictors of late events were calculated using multivariate Cox regression analysis. RESULTS: The perioperative mortality rate was 3.6% (n = 4). The cumulative survival rate at 5, 10, and 15 years was 93%, 80%, and 72%, respectively, and symptom-free survival, 77%, 50%, and 33%, respectively. Predictors of late death were New York Heart Association class III or IV (p < 0.05), congestive heart failure (p < 0.05) and additional procedures (p < 0.05). The left ventricular outflow tract gradient was nearly eliminated in all patients, the left atrial dimension decreased significantly during the early years, and left ventricular dilatation occurred late in 17 patients. CONCLUSIONS: Septal myectomy is associated with a low perioperative mortality and a high late survival rate (72% at 15 years' follow-up). Septal myectomy is still an excellent modality in the treatment strategy for symptomatic patients with hypertrophic obstructive cardiomyopathy.

Adolescent↗
PubMed1998

Cardiac risk after mediastinal irradiation for Hodgkin's disease.

PURPOSE: To evaluate the risk of cardiac lesions after conventionally fractionated irradiation (Rt) of the mediastine with or without chemotherapy (Ct) in patients with Hodgkin's disease (HD) and to relate them to known cardiovascular risk factors. PATIENTS AND METHODS: Between 1964 and 1992, 352 (total group) patients with HD were treated with curative intention using Rt with or without Ct including the mediastine and had a follow-up of at least 1 year. More than 96% of the patients had a complete follow-up. One hundred forty-four patients (64% of the living patients, heart study group) have regular follow-up in our department and had a special heart examination including rest and exercise ECG, echocardiography and myocardial perfusion scintigraphy (112 patients). Doses per fraction in the anterior heart region were between 1.3 and 2.1 Gy. Total doses were between 30.0 and 42.0 Gy in 93% of cases. The mean length of follow-up was 11.2 years (range 1.0-31.5 years). Other cardiovascular risk factors evaluated were body mass index, blood pressure, smoking history, diabetes mellitus, hypercholesterolemia and history of coronary artery disease before Rt. RESULTS: In the total group, the risk of fatal cardiac ischemic events and/or of sudden unexpected death was significantly higher than expected with a relative risk of 4.2 for myocardial infarction and 6.7 for myocardial infarction or sudden death. In female patients and in patients without other cardiovascular risk factors, the risk of fatal or non-fatal ischemic cardiac events was not significantly different from the expected value. In the subgroup with no cardiovascular risk factors and treatment without Ct, there was no ischemic or other major cardiac event. Echocardiography showed valvular thickenings in a large amount of the patients (the cumulative risk after 30-year follow-up was above 60%) but mostly without hemodynamic disturbance. In patients without hypertension and without coronary artery disease, findings of perfusion scintigraphy and echocardiographic evaluation of systolic and diastolic function were normal. Treatment with Ct was not a significant risk factor for cardiac events but the number of patients whose treatment included adriamycin and with a follow-up exceeding 10 years is to low for a definitive evaluation. CONCLUSIONS: In patients without the usual cardiovascular risk factors (smoking, hypertension, obesity, hypercholesterolemia, diabetes mellitus) the risk of serious cardiac lesions after conventionally fractionated irradiation of the mediastinum with an intermediate total dose between 30 and 40 Gy is low. Also the cardiac risk of the combination of this irradiation with Ct including adriamycin with a total dose between 200 and 300 mg/m2 seems low but further long-term observation is necessary.

Adolescent↗
PubMed1998

Echogenic structures in the left atrioventricular groove: diagnostic pitfalls.

A variety of echogenic structures that can be detected by echocardiography in the left atrioventricular groove are best seen in the parasternal long-axis view and can be missed if not carefully looked for. Normal anatomic structures or variants can be seen, for example, dilated coronary sinus, persistent left superior vena cava, or lipomatous tissue. Degenerative or inflammatory processes of the mitral annulus (calcification of the mitral annulus, mitral annular abscess) and aneurysms of the left circumflex coronary artery or of the descending aorta can depict pathologic structures. Hiatal hernia and tumors can be found as well.

Aortic Aneurysm, Thoracic↗