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Biomedical subjects

X Jeanrenaud

Publications and source records attributed to X Jeanrenaud.

36 records · Page 2Linked to original sources
PubMed1996

Surgical prophylaxis of recurrent stroke in patients with patent foramen ovale: a pilot study.

Prevention of recurrent stroke in adults with patent foramen ovale represents a therapeutic challenge. Antiplatelet or anticoagulant treatment is widely introduced, but its exact indication is not known. In this pilot study, eight men and three women with previous ischemic cerebral events underwent direct surgical closure of the patent foramen ovale. Mean age was 39.4 (from 30 to 58) years. No coexisting cause of stroke was found after extensive investigations, including blood and coagulation tests, echocardiography, 24-hour three-lead electrocardiographic monitoring, extracranial and transcranial Doppler ultrasonography, and cerebral angiography. Criteria for operation also included at least two of the following: atrial septal aneurysm, multiple cerebral infarcts, a history of multiple cerebral events, and Valsalva strain before stroke. Before operation, one patient had two shunts (1 patent foramen ovale, 1 intrapulmonary shunt). No intraoperative or postoperative complications occurred, but a few hours after operation transient arrhythmias developed in two patients without atrial fibrillation, hemodynamic instability, or embolism. During a median follow-up of 12.2 months, no patient had recurrent stroke. All patients prospectively underwent brain magnetic resonance imaging and contrast echocardiography with simultaneous transcranial Doppler ultrasonography. A residual right-to-left interatrial shunt, smaller than the preoperative one, was observed in only one patient, whereas no lesion was seen on magnetic resonance imaging. Our study suggests that surgical closure of patent foramen ovale in patients with presumed paradoxic embolism is safe, with no recurrent stroke in the first year of follow-up. Further studies are needed to evaluate the long-term prognosis of patients with versus without operation and to define the role of operation as an alternative to prolonged antithrombotic treatment.

Adult↗
PubMed1996

Stroke recurrence in patients with patent foramen ovale: the Lausanne Study. Lausanne Stroke with Paradoxal Embolism Study Group.

Patent foramen ovale (PFO) is more common in patients with stroke than in matched controls, but the stroke mechanism and late prognosis are not well known. We studied features, coexisting causes, and recurrences of stroke in 140 consecutive patients (mean age 44 +/- 14 years) with stroke and PFO admitted to a population-based primary-care center. We selected the patients from 340 patients (41%) aged < or = 60 years with acute stroke. The initial event was brain infarction in 118 patients (84%) and TIA in 22 (16%). Intracranial embolic occlusions were present on angiography or transcranial Doppler in most patients admitted within 12 hours of onset, whereas a venous source was clinically apparent in only six patients (5.5%). Pulmonary embolism, Valsalva maneuver at onset, and coagulation abnormalities were rare, but one-fourth of the patients had an interatrial septum aneurysm (ISA) that coexisted with PFO. An alternative cause of stroke was present in only 22 patients (16%), usually cardiac (atrial fibrillation, severe mitral valve prolapse, akinetic left ventricular segment). During a mean follow-up of 3 years, the stroke or death rate was 2.4% per year, but only eight patients had a recurrent infarct (1.9% per year). This low rate of recurrence contrasted with the severity of initial stroke, which left disabling sequelae in one-half the patients. Multivariate analysis showed that interatrial communication, a history of recent migraine, posterior cerebral artery territory infarct, and a coexisting cause of stroke were associated with recurrence, whereas ISA and treatment type (coagulant or antiaggregant therapy, surgical closure of PFO) were not. However, given the low number of events, these findings must be taken with caution. In conclusion, our study shows that stroke associated with PFO with or without ISA is not commonly due to a coexisting cause of stroke. It is usually embolic, although a definite source cannot often be demonstrated. The presenting stroke is often severe, but recurrence is uncommon. The demonstration of factors associated with a higher risk of recurrence in subgroups of patients is critical for the long-term management of these patients.

Adult↗
PubMed1996

Prognosis after stroke followed by surgical closure of patent foramen ovale: a prospective follow-up study with brain MRI and simultaneous transesophageal and transcranial Doppler ultrasound.

BACKGROUND: The risk of stroke and the long-term prognosis of recurrent strokes in young patients with patent foramen ovale (PFO) are not well known. For this reason, the treatment of these patients remains empirical. An alternative treatment to prolonged antithrombotic therapy may be surgical closure of the PFO. METHODS: Thirty patients (20 men and 10 women) with stroke and PFO were prospectively selected among 138 patients with stroke and PFO for a study of surgical closure of PFO at our center. Eligible patients were < 60 years old, had negative results of a systematic search for another cause of stroke (first criterion), and met two of the four following criteria: (1) recurrent clinical cerebrovascular events or multiple ischemic lesions on brain MR, (2) PFO associated with an atrial septal aneurysm, (3) > 50 microbubbles counted in the left atrium on contrast transesophageal echocardiography (TEE), and (4) Valsalva maneuver or cough preceding the stroke. Patients selected in this manner for surgery were considered to be a subgroup with a higher risk of stroke recurrence. RESULTS: All patients had a direct suture of PFO while under cardiopulmonary bypass without recorded early or delayed significant complication. All patients underwent a new brain MRI and TEE simultaneous with transcranial Doppler ultrasonography after contrast injection at 8 +/- 3 months after surgery. After a mean follow-up of 2 years without antithrombotic treatment, no recurrent cerebrovascular event (stroke or transient ischemic attack [TIA]) and no new lesion on MRI had developed. Postoperative contrast TEE and transcranial Doppler ultrasonography showed that two patients had residual interatrial right-to-left shunting, although much smaller than before surgery, associated with single versus double continuous suture. CONCLUSIONS: Our study of 30 selected stroke patients with surgical suture of PFO showed a stroke recurrence rate of 0% and no significant complication. Residual right-to-left shunting may be avoided by double continuous suture of the PFO. In the absence of controlled studies to guide individual therapeutic decisions, our findings show that PFO closure can be done safely and may be considered to avoid recurrence in selected patients with long life expectancy and presumed paradoxic embolism.

Adult↗
PubMed1996

Doppler echocardiographic assessment of the new ATS medical prosthetic valve in the aortic position.

Advancing The Standard (ATS) Medical (ATS Medical Inc., Minneapolis, MN) is a new mechanical bileaflet valve, composed of pyrolitic carbon. The aim of this study was to define in a blinded manner the Doppler echocardiographic characteristics of normally functioning ATS Medical prostheses with respect to their size. Forty consecutive patients (29 men, mean age 58 +/- 13 years), clinically stable, and without evidence of valve dysfunction, were studied from 1993 to 1995. Doppler echocardiography was performed at least 3 months after valve replacement with ATS Medical valves (5 n degrees 21, 8 n degrees 23, 12 n degrees 25, 10 n degrees 27, 5 n degrees 29). Maximum and mean transprosthetic pressure gradients were calculated by the simplified Bernoulli equation. Functional valve surface area was assessed by the continuity equation using the external diameter of the prostheses to calculate the subaortic surface area. The Doppler velocity index was obtained by the ratio of subaortic and transaortic velocities and the performance index was calculated dividing the effective orifice area by the actual orifice area. For the most commonly used aortic valve (25 mm), the maximum pressure gradient was 17 +/- 8 mmHg, the mean gradient 11 +/- 4 mmHg, the functional surface area 2.2 +/- 0.4 cm2, the Doppler velocity index 0.44 +/- 0.07, and the performance index 0.68 +/- 0.11. This study provides the normal range for Doppler hemodynamic characteristics of the various sizes of the ATS valve.

Adult↗
PubMed1995

[Cardiac pacemaker for the treatment of obstructive hypertrophic cardiomyopathy, a concept which is gaining ground].

Pacing reduces the sub-aortic pressure gradient in hypertrophic obstructive cardiomyopathy. This phenomenon was described long ago but only recently, with the development of sophisticated pacemakers, has it become possible to use pacemakers for the long term treatment of this disease. The acute hemodynamic improvement with pacemaker treatment is well documented. The reason for this acute and chronic improvement is of multiple origin. Pacing modulates the activation sequence of the left ventricle, reduces contractility, reduces subaortic flow velocities, influences mitral valve movement and leads to remodeling of the ventricle in the long term. All these factors together explain the clinical and hemodynamic improvement in patients suffering from hypertrophic obstructive cardiomyopathy.

Aorta, Thoracic↗
PubMed1995

Cardiac perforation after surgical repair of pectus excavatum.

Five days after surgical repair of pectus excavatum, this 7-year-old boy had a right-sided Kirschner wire protruding beneath the skin. The wire was repositioned blindly. Severe congestive heart failure developed. Surgical exploration showed a pierced right atrium, a torn septal leaflet of the tricuspid valve and noncoronary aortic cusp, and a large traumatic ventricular septal defect. The outcome and the indications and possible complications of surgery are discussed.

Bone Wires↗
PubMed1994

Coronary angioplasty in octogenarians: immediate and long-term results and comparison with a younger population.

The safety and efficacy of percutaneous transluminal coronary angioplasty (PTCA) was examined in a group of 91 octogenarians during 133 consecutive procedures and compared to the younger part of our PTCA population (3,443 procedures) during an 8-year study period. Most octogenarians presented with refractory or unstable angina pectoris and multivessel involvement, but had normal left ventricular function. The angiographic success rate was 84%. Technical failure was observed in 12% of cases and complications in 14%. Two early procedure related deaths were observed. Restenosis was estimated at 24%. The proportion surviving and the proportion without cardiac event estimated by the Kaplan-Meier method at 2 years were 0.89 and 0.60, respectively. In comparison to the younger population, the immediate angiographic success was lower as a result of a higher incidence of technical failure (P less than 0.05). Otherwise, no difference in terms of restenosis or overall related complication rate was noted (P greater than 0.1). It is concluded that PTCA is an efficient and safe therapeutic option for octogenarians with severe or refractory angina pectoris. Technical failure is more frequently observed than in younger patients and explains a lower immediate angiographic success. Nevertheless, at 2-years follow-up, a large majority of patients are alive and asymptomatic.

Age Factors↗
PubMed1994

[Cardiac pacing in obstructive hypertrophic cardiomyopathies].

Up until recently, the first-line treatment of obstructive hypertrophic cardiomyopathy was pharmacological and surgical in refractory cases. However, the immediate beneficial effect of a cardiac pacing on infra-aortic obstruction has been known for many years. The development of sophisticated two-chamber pacemakers and their use in patients with obstructive hypertrophic cardiomyopathy has confirmed their beneficial effect both in terms of haemodynamic and clinical parameters. There appears to be many reasons for this advantageous effect and only some of them have been elucidated, including alteration of the activation sequence of the left ventricle secondary to apical ectopic electrical activation and reduction of the contact time of the mitral valve with the proximal septum and, in the long term, ventricular remodelling secondary to release of the outflow obstruction. The increasing number of publications reporting a beneficial effect of two-chamber pacemakers in these patients justifies consideration of this approach in all patients refractory to drug therapy.

Cardiac Pacing, Artificial↗
PubMed1993

Initial experience with a new balloon-on-a-wire catheter: the Bijou.

This paper presents our initial experience with a new low-profile balloon "on-a-wire" catheter, the Bijou. The concept of this balloon is to provide an additional side lumen with the advantages of (1) the ability to measure pressure gradient, (2) the possibility of drug infusion, and (3) the ability to advance a steerable guidewire through this side lumen. The balloon has been tested in 15 patients; 14 underwent an elective procedure for stable angina pectoris (with 2 cases of restenosis) and one an emergency angioplasty in a case of acute myocardial infarction. The stenosis was located on the left anterior descending artery in 11 procedures, on the right in 3, on a marginal branch in 2, on the circumflex and a saphenous vein graft in 1. All stenoses could be dilated successfully (residual stenosis < 25%). The transstenotic pressure gradient felt from 49 +/- 13 mmHg to 7 +/- 4 mm Hg after angioplasty. Except for an uncomplicated dissection in 3 patients, no other complication was noted. With this new catheter, the double-lumen configuration adds the advantages of an "over-the-wire" to an "on-a-wire" system.

Aged↗
PubMed1992

Effects of dual-chamber pacing in hypertrophic obstructive cardiomyopathy.

Although attempts have been made to treat hypertrophic obstructive cardiomyopathy with right ventricular pacing, the usual treatment for those refractory to medical therapy is open heart surgery. To assess in detail the value of non-surgical therapy the effects of acute and long-term dual-chamber pacing were investigated in 13 patients with hypertrophic obstructive cardiomyopathy refractory to medical treatment. In the first part of the study, atrioventricular (AV) sequential pacing was found to reduce peak subaortic pressure gradient in 12 of the 13 patients, from 82 (SD 42) to 47 (34) mm Hg (p less than 0.002), without concomitantly reducing aortic blood pressure or cardiac output. This effect was related to AV interval. In the second part of the study, a dual-chamber pacemaker was implanted in 8 patients and programmed to the optimum AV interval for the individual (50-90 ms). Patients were followed up for up to 62 months. Pacing resulted in a significant and long-lasting reduction in severity of angina pectoris (from NYHA class 3 to 1) and dyspnoea (from NYHA class 3 to 2). Echocardiography showed no significant change in septal thickness or left ventricular contractility but there was a trend to a spontaneous decrease in obstruction. In patients with hypertrophic obstructive cardiomyopathy, synchronised and ventricular pacing at optimum AV interval for the individual reduces the intraventricular pressure gradient and improves functional tolerance. Since the effect is longlasting, such pacing should be deemed an alternative therapy to surgery in selected cases.

Adult↗
PubMed1992

[Value of physiological cardiac stimulation in the treatment of hypertrophic obstructive cardiomyopathy].

Subaortic pressure gradient in hypertrophic obstructive cardiomyopathy (HOCM) is the consequence of a dynamic obstruction of the left ventricular outflow tract linked to the presence of a hypertrophied septum. We tried to induce an altered septal motion electrically by physiologic pacing. We studied 8 patients (6 men, 2 women, mean age 60 +/- 13 years) with symptomatic HOCM, resistant to optimal drug treatment. During a hemodynamic study, dual chamber pacing significantly reduced the preexistent subaortic pressure gradient, from 69 +/- 39 to 34 +/- 26 mm Hg (p less than 0.004), without concomitant reduction of aortic pressure or cardiac output. This reduction was dependent upon a optimized AV interval. A dual chamber pacemaker (PM) was then implanted and programmed to VDD mode and optimized AV delay interval (50-90 ms), warranting full ventricular capture. The follow-up of 3 to 30 months showed a significant reduction of both angina (from NYHA class 3 to 1: p less than 0.009) and dyspnea (from 3 to 2: p less than 0.03). An echo-doppler study in 6 patients proved the persistence of the beneficial effect of the stimulation by showing a significant reappearance of the subaortic pressure gradient after switching off the PM, from 44 +/- 29 in VDD pacing mode to 77 +/- 44 mm Hg (p less than 0.02). We conclude that atrial synchronized ventricular pacing, together with an optimized AV interval, significantly reduces the outflow gradient and improves symptoms in patients with HOCM. An altered ventricular activation sequence with late septal activation is suspected to be the mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Quantitative analysis of systolic function of the right ventricule by Doppler echocardiography].

The recording of the velocity of tricuspid valve regurgitation by continuous wave Doppler enables the calculation of the instantaneous systolic pressure gradient between the right ventricle and right atrium. As right atrial pressure is relatively constant, the rate of acceleration of the regurgitant jet reflects the quality of the rise in pressure in the right ventricle in early diastole, and therefore right ventricular contractility. The authors studied 3 Doppler parameters of the rate of velocity increase of the tricuspid regurgitation; the maximum rate of acceleration (dV/dt max), the maximum derivative of the pressure (dP/dt max) and the mean rate of increase in pressure (T). The interobserver variability of these indices is low (r greater than 0.96); reproducibility is good in patients with sinus rhythm but mediocre in atrial fibrillation. The comparison of the Doppler indices with the right ventricular isotopic fraction in 26 patients with tricuspid regurgitation showed a good correlation (dV/dt max, r = 0.79, p less than 0.0001; dP/dt max, r = 0.69, p less than 0.0001; T, r = 0.60, p = 0.0012). These results show that right ventricular systolic function can be evaluated by continuous wave cardiac Doppler by recording the spectral envelope of tricuspid regurgitation.

Aged↗
PubMed1990

[Patent foramen ovale and cerebral infarct in young patients].

Over a six months' period we prospectively studied the prevalence of patent foramen ovale (PFO) in patients under 50 years of age admitted for cerebral infarction as assessed by cerebral computed tomography. The study recruited 16 patients (9 male, 7 female, mean age 39 +/- 10 years). Before the contrast study, 5 patients had other identifiable sources of stroke after neurologic investigations and 2-D echocardiography with color-Doppler, whereas 11 had no precise origin. The overall prevalence was 50% with 8 PFO demonstrated, 6 during normal breathing and two during a coughing test. All were in the sub-group of 11 patients without a predetermined source of stroke (prevalence 73%) and in 83% of patients aged under 40. In accordance with the literature, we found a high prevalence of PFO in the ischemic cerebral infarction population aged under 50 years and without another possible source of stroke; this prevalence is higher in patients under 40 years old. This observation confirms the suspicion of paradoxical embolism in these cases.

Adult↗
PubMed1990

[Study of valvular prostheses by Doppler echography].

Doppler echocardiography is a reliable non-invasive method of following up patients with prosthetic heart valves. Transthoracic M mode and two-dimensional echo allow evaluation of the movement of the mobile element of the prosthesis and of the size of the cardiac chambers. Doppler studies (transprosthetic pressure gradient, valve surface area, trans- and periprosthetic regurgitation) give an indication of the hemodynamic profile of the prosthesis. Transesophageal echocardiography is especially useful when there are abnormalities suggestive of prosthetic valve dysfunction (fever, systemic embolism, clinical symptoms, haemolysis...).

Aortic Valve↗
PubMed1984

Benign outcome in unoperated large cerebellar haemorrhage. Report of 2 cases.

We studied two patients with large cerebellar haemorrhages, who were conscious on admission and did not deteriorate during the following days. Surgical decompression was not performed and the patients regained their former level of activity, except for moderate persisting ataxia. We suggest that cerebellar haemorrhage may have a benign spontaneous outcome, more often than previously assumed from autopsy series. The main selection criteria for surgery is an impaired state of consciousness and evidence of neurological worsening. Taken alone, the size of the haemorrhage on computerized tomography is not a reliable criterion for surgery.

Aged↗
PubMed1983

Effect of an enkephalin-analogue (FK 33-824) on glucose tolerance in man.

The purpose of the present work was to study the effect of a methionine-enkephalin analogue (FK 33-824) on glucose tolerance in man. Groups of 5 to 8 normal subjects were given a 0.5 mg im injection of the drug or placebo just before a 100 g oral glucose load or a 0.5 g/kg iv glucose load. In the enkephalin analogue treated subjects, diminished insulin response to glucose was observed following the oral glucose load, with insulin values significantly lower than in the controls from time 10 to 90 min, but no corresponding change in the glucose curve. This effect was not observed when glucose was given iv in another group of 5 subjects in whom the significant blunting of the insulin response was accompanied by a significant decrease in glucose tolerance. These observations demonstrate that in man, enkephalin produces a decrease in insulin secretion in response to both oral and iv glucose loads. The absence of any marked impairment in glucose tolerance in the oral test in spite of the decreased insulin response suggests that enkephalin might have an additional effect in delaying glucose absorption.

Adult↗