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Biomedical subjects

J M Frapier

Publications and source records attributed to J M Frapier.

At least 19 recordsLinked to original sources

[Surgery of ventricular tachycardia in post-infarction left ventricular aneurysm].

The treatment of post-infarction ventricular tachycardias with antiarrhythmic drug therapy, implantable automatic defibrillators, radiofrequency ablation, also includes different surgical procedures such as endocardial resection of the infarct scar, encircling endocardial ventriculotomy and endocardial cryoablation or thermoexclusion by laser. These procedures may be extensive or limited, guided or not by preoperative mapping. The aim of this review of the literature is to update our knowledge of these different surgical techniques and to define their indications.

Cryosurgery↗

Recurrence of postoperative aortic fistulas: is there an ideal method of prevention? A case report.

There are very few cases in English literature of recurrent postoperative aortic fistulas (RPAFs). These are neo-communications between the aortic bloodstream and the lumen of contiguous organs which occur after unpredictable periods from surgical treatment of a previous fistula. The supradiaphragmatic aorta may fistulize into the airways, pulmonary circulation, oesophagus, and cardiac chambers; the infradiaphragmatic aorta into the intestine, stomach, and vena cava. According to the etiology, aortic fistulas are categorized as postoperative (or secondary) and spontaneous (or primary), and RPAF may be considered a subgroup of secondary fistulas. They may recur even more times in the same patient, hence the role of prevention is of the utmost importance. The simultaneous respect of different surgical principles is crucial to make the risk of recurrence less likely. Surgical treatment represents a real challenge due to the emergency conditions and redo nature of operations. Mortality rate is very high. In this article, we describe a case of recurrent aorto-duodenal communication, we discuss the principles of prevention both for the supra and infradiaphragmatic aorta, we introduce some modifications to the classic categorization and we present the first RPAF literature review.

Aorta, Abdominal↗

[Cardiac surgery in the octogenarian: what risks for what benefits?].

About 1 to 8% of patients referred for cardiac surgery in industrialised countries are octogenarians. Hospital mortality is high and depends on age, type of surgery and other predictors of death which are female gender, left congestive heart failure, history of myocardial infarction, chronic obstructive lung disease, renal insufficiency, carotid and others vascular diseases. Morbidity is also very high. Besides supraventricular arrhythmias, respiratory failure is the main cause (20 to 30%) of morbidity, followed by cerebrovascular accident and renal failure. Due to this high rate of postoperative events, the length of stay is significantly increased. At follow-up however, excellent functional status and survival rate is afforded by the operative procedure. The main problem remains the selection of patients in order to improve results.

Age Factors↗

Simple surgical technique to prevent direct secondary aortoenteric fistulas.

To prevent direct secondary aortoenteric fistulas, a devastating complication of abdominal aortic surgery, we describe here a rapid, very easy to perform and no cost operating technique. A part about 4 cm long of the vascular prosthesis was cut to obtain a partial tailored ring which was passed through the prosthesis. After the anastomosis was realized, the tailored ring was hitched up to totally cover proximal anastomosis and prevent direct contact between aorto-prosthetic anastomosis and the bowel.

Aortic Aneurysm, Abdominal↗

[Extracorporeal circulation: an extraordinary tool that is not just for cardiac surgeons].

Extracorporeal circulation (ECC) is not only used for open heart surgery. There are also other surgical and medical applications. ECC can be used for encephalic arteries surgery to induce hypothermia and maximally protect the brain. Femoro-femoral ECC may be needful for urgent traumatologic surgery of the supra-aortic trunci. Intracranial aneurysm repair can occasionally necessitate deep hypothermia and circulatory arrest with ECC. Renal cell carcinomas may metastasize to the right atrium and surgery with ECC is mandatory for complete excision. Some reports in the literature mention use of ECC for hepatic surgery of intra-hepatic aneurysms. With acute peripheral ischemia, metabolites in the affected limb can be washed out with good results. Medical indications for ECC are numerous with pulmonary assistance as one of the foremost when mechanical ventilation failed. Homogeneous and rapid rewarming of hypothermic patients can be achieved with ECC. Finally, some groups have reported the use of ECC to administer chemotherapy in limb melanoma.

Cardiac Surgical Procedures↗

Cyclosporin A increases basal intracellular calcium and calcium responses to endothelin and vasopressin in human coronary myocytes.

Cyclosporin A (CsA) is a widely used immunosuppressive agent with severe side effects including hypertension. Here, we investigated the effects of CsA on intracellular free calcium ([Ca(2+)](i)) and the mechanisms involved in vasoconstriction in cultured human coronary myocytes. We used the Fura-2 technique for Ca(2+) imaging. Acute application of CsA at therapeutic concentrations (0.1-10 micromol/l) had no effect. Chronic exposure to CsA (1 micromol/l) for 24 h induced a small (20 nmol/l) but highly significant increase of basal [Ca(2+)](i) and enhanced the occurrence of spontaneous Ca(2+) oscillations. Endothelin- and vasopressin-induced rises of [Ca(2+)](i) were also enhanced. The demonstration that CsA increases basal [Ca(2+)](i) in addition to its impact on agonist receptor stimulation is of major importance for new therapeutic approaches.

Adolescent↗

[Chronic constrictive pericarditis in African children: report of a case].

The chronic constrictive pericarditis is a rare affection, with multiple etiologies and concerning especially the adult. We report a case of chronic constrictive pericarditis in an African child in whom no etiology was found. A review of the literature raises the characteristics of chronic constrictive pericarditis for a better therapeutic management.

Africa, Eastern↗

[Results of coronary artery surgery in octogenarians].

Over an 11 year period from January 1990 to December 2000, 3282 patients underwent isolated or combined surgical myocardial revascularisation. In this group, 42 were aged 80 or over (maximum 87 years), 1.3% of the total patient population. The mean age of this subgroup was 81.8 +/- 1.75 years) with a male predominance (61.9%). All patients were autonomous and considered to be in good general and psychological health. Preoperative coronary angiography showed 33.3% of left main stem lesions either alone or associated with a right coronary lesion. The ejection fraction was over 50% in 78.6% of cases. Saphenous vein grafts were used in all but 5 patients who also had left internal mammary artery grafts. Thirteen patients (31%) underwent combined valvular surgery (11 aortic and 2 mitral valve) and 2 patients underwent combined vascular surgery. Three patients were operated as an emergency. A total of 5 patients died in the first 30 postoperative days, a hospital mortality of 11.9%. There were 2 postoperative hemiplegias and 2 cases of renal failure which were aggravated in the postoperative period. The other patients were discharged from hospital with a satisfactory cardiac and functional status. The global mortality was 14% at 3 years and 18% at 5 years. The main bad prognostic factor for survival was the association of aortic valve surgery. In selected octogenarians in good general and psychological health without severe co-morbid conditions, surgical myocardial revascularisation may be considered with an acceptable operative risk.

Aged↗

Postoperative exercise tolerance after aortic valve replacement by small-size prosthesis: functional consequence of small-size aortic prosthesis.

OBJECTIVES: The objective of this study was to determine whether a small-size valve prosthesis contributes to exercise intolerance, as assessed by VO2 measurement during an exhaustive cycle ergometer exercise. BACKGROUND: The determinants of exercise capacity after mechanical aortic replacement are not well known. The selection of small valve sizes has, however, been described as an independent predictor of exercise intolerance as assessed by exercise duration. Maximal oxygen uptake (VO2max) is a good index of exercise tolerance. METHODS: Fourteen patients were eligible, with a mean age of 62 +/- 6 years. Before surgery, the mean left ventricular ejection fraction (LVEF) was 73 +/- 8%. Two valve types with small diameter (19 to 21 mm) were used: Medtronic Hall and St Jude Medical. A healthy sedentary control group (n = 14) paired for age, weight and size was constituted. After one year of follow-up, cardiorespiratory tests were performed. In addition, the gradients through the prostheses were determined by continuous pulse Doppler at rest and immediately after the cardiorespiratory test. RESULTS The exercise tolerance was not significantly different between the control group and patient group: VO2 peak (21.7 vs. 20.4 ml/kg/min; p = 0.42), workloads (115 vs. 93 W; p = 0.13) and ventilatory parameters were similar. The mean and peak gradients at rest and during exercise were not correlated with VO2max. CONCLUSIONS: Valve replacement by small aortic prosthesis does not seem to be a factor of exercise intolerance as assessed by VO2max in patients without LVEF dysfunction before surgery.

Aged↗

Vertebral artery surgery with cardiopulmonary bypass and deep hypothermia.

Deep hypothermia was proposed to prevent neuronal ischemia and stroke during surgical procedures on arteries that supply the brain, especially with extended occlusive lesions on both internal carotid arteries. The interest of this therapeutic option is still under discussion, even in the case of combined cardiac and cerebrovascular surgery. We report the case of a 53-year-old male who was admitted to our institution for symptomatic vertebrobasilar insufficiency. Angiography showed a thrombosis of both internal carotid arteries, stenosis of both external carotid arteries, and a tight proximal stenosis of a dominant right vertebral artery. Endarterectomy and angioplasty of the origin of the right external carotid artery was done first to increase the blood supply to the brain via collateral arteries connecting the extra- and intracranial networks. Six weeks after this, a right-sided vertebral-to-carotid artery anastomosis was performed during cardiopulmonary bypass (CPB)-induced deep hypothermia for optimal neuronal protection, with good results. However, early thrombosis of the right vertebral artery requiring reintervention in normothermia, without any stroke, indicate that deep hypothermia was unnecessary in this case, probably because of the previous natural and surgical development of collateral circulation. However, there was no means of predicting this in a reliable manner before the procedure and deep hypothermia appeared a safe technique for neuronal protection without any specific postoperative complications.

Anastomosis, Surgical↗

[Is atypical sodium current related to arterial pathophysiology?].

Primary cultured human coronary myocytes, derived from patients with end-stage heart failure (NYHA, classes III and IV) caused by an ischemic disease and undergoing heart transplantation, express a voltage-gated tetrodotoxin-sensitive sodium current (INa). This current has atypical electrophysiological and pharmacological properties and regulates intracellular sodium ([Na+]i) and calcium ([Ca2+]i). Our work is aimed at identifying its role and regulation of expression during pathophysiology. We currently investigate whether INa is expressed in vascular smooth muscles cells (VSMCs) isolated from either healthy or diseased (atheromatous) arteries in human and, in parallel, in pig, rabbit and rat. Cells were enzymatically isolated, primary cultured and macroscopic INa were recorded using the whole cell patch clamp technique. We found that INa is expressed in VSMCs grown from human aortic (90%; n = 48) and pulmonary (44%; n = 16) arteries and in the human aortic cell line HAVSMC (94%; n = 27). INa was also detected in pig coronary (60%; n = 25) and rabbit aortic (47%; n = 15) VSMCs, but not in rat aortic myocytes (n = 30). These different INa were activated at similar range of potentials (approximately -45 mV), had similar sensitivity to tetrodotoxin (IC50 around 5 nM) and similar density (2 to 4 pA/pF). Their expression was related to cell dedifferentiation in vitro. However, INa was observed more frequently in human myocytes derived from diseased arteries (ischemic cardiopathy) than in those derived from healthy tissues (dilated cardiopathy). In conclusion, INa may contribute to increase the basal arterial contractility and play a role in pathological situations including hypertension.

Action Potentials↗

Aspergillus flavus mitral valve endocarditis after lung abscess.

A 16-year-old male with bone marrow failure due to chemotherapy for recurrent acute lymphoblastic leukemia developed an abscess in the lower lobe of the left lung draining through a bronchogastric fistula, as well as mitral valve endocarditis with large vegetations. After a course of antifungal therapy, the left lobe was removed and the fistula closed. The mitral valve was then replaced, after a failed attempt at valve repair, by a mechanical, double-leaflet prosthesis. Microscopy of the lung and heart specimens disclosed hyphae. Cultures of both specimens on Sabouraud's medium recovered a fungus, which was identified by culturing on Czapek's medium as Aspergillus flavus. Despite further antifungal therapy, fatal embolism developed. The emboli contained the same A. flavus as the valve and lung specimens. This case confirms the grim prognosis of primary Aspergillus endocarditis in immunocompromised patients, and suggests that delayed surgical treatment and the presence of another focus of Aspergillus infection may increase the risk of death.

Adolescent↗

Regulation of Ca2+ homeostasis by atypical Na+ currents in cultured human coronary myocytes.

Primary cultured human coronary myocytes (HCMs) derived from ischemic human hearts express an atypical voltage-gated tetrodotoxin (TTX)-sensitive sodium current (I(Na)). The whole-cell patch-clamp technique was used to study the properties of I(Na) in HCMs. The variations of intracellular calcium ([Ca2+]i) and sodium ([Na+]i) were monitored in non-voltage-clamped cells loaded with Fura-2 or benzofuran isophthalate, respectively, using microspectrofluorimetry. The activation and steady-state inactivation properties of I(Na) determined a "window" current between -50 and -10 mV suggestive of a steady-state Na+ influx at the cell resting membrane potential. Consistent with this hypothesis, the resting [Na+]i was decreased by TTX (1 micromol/L). In contrast, it was increased by Na+ channel agonists that also promoted a large rise in [Ca2+]i. Veratridine (10 micromol/L), toxin V from Anemonia sulcata (0.1 micromol/L), and N-bromoacetamide (300 micromol/L) increased [Ca2+]i by 7- to 15-fold. This increase was prevented by prior application of TTX or lidocaine (10 micromol/L) and by the use of Na(+)-free or Ca(2+)-free external solutions. The Ca(2+)-channel antagonist nicardipine (5 micromol/L) blocked the effect of veratridine on [Ca2+]i only partially. The residual component disappeared when external Na+ was replaced by Li+ known to block the Na+/Ca2+ exchanger. The resting [Ca2+]i was decreased by TTX in some cells. In conclusion, I(Na) regulates [Ca2+]i in primary cultured HCMs. This regulation, effective at baseline, involves a tonic control of Ca2+ influx via depolarization-gated Ca2+ channels and, to a lesser extent, via a Na+/Ca2+ exchanger working in the reverse mode.

Adult↗

Malignant ventricular arrhythmias revealing anomalous origin of the left coronary artery from the pulmonary artery in two adults.

We report two cases of anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA), revealed by malignant ventricular arrhythmias in adult patients. A two coronary system was re-established in both patients, and cryotherapy was performed on one of the patients who, in addition, presented ventricular aneurysm triggering ventricular tachycardia.

Adult↗