[Short-term results of video-assisted lung cancer surgery in octogenarians]

INTRODUCTION

Due to an increase in life expectancy, onco-pulmonologists and thoracic surgeons are more frequently faced with octogenarian patients with lung cancer. In this age group, treatment modalities may need to be revised because of the increasing presence of comorbidities. Surgery remains the reference treatment for early stage disease, but mortality rates and postoperative complications are higher in this group of patients. One of the solutions to reduce the operative risk would be to develop videoassisted thoracoscopic pulmonary resection surgery. The aim of this study was to evaluate the results of this form of lung cancer surgery in octogenarians.

METHODS

All patients 80 years old or more who underwent videoassisted lung cancer surgery from 2014 to 2018 at Lyon University Hospital were included. Wedge resections and diagnostic procedures were excluded.

RESULTS

Nineteen patients (13 men, 6 women) were included. The median age was 82 years old. All patients had undergone videoassisted lobectomy. Three patients required conversion to thoracotomy (15.8%). All patients underwent complete resection (R0). One patient had N1 lymph node involvement, all others were N0. The postoperative complication rate was 68.4%, the majority of which were grade II of the Clavien classification. Perioperative mortality was 5.3%.

CONCLUSIONS

Videoassisted lung cancer resection in a selected population of octogenarians is associated with satisfactory short-term results. It is reasonable to favour minimally invasive techniques in this population, even if the proof of their superiority has not yet been firmly established.

Blood CD9+ B cell, a biomarker of bronchiolitis obliterans syndrome after lung transplantation

Bronchiolitis obliterans syndrome is the main limitation for long-term survival after lung transplantation. Some specific B cell populations are associated with long-term graft acceptance. We aimed to monitor the B cell profile during early development of bronchiolitis obliterans syndrome after lung transplantation. The B cell longitudinal profile was analyzed in peripheral blood mononuclear cells from patients with bronchiolitis obliterans syndrome and patients who remained stable over 3 years of follow-up. CD24^hi CD38^hi transitional B cells were increased in stable patients only, and reached a peak 24 months after transplantation, whereas they remained unchanged in patients who developed a bronchiolitis obliterans syndrome. These CD24^hi CD38^hi transitional B cells specifically secrete IL-10 and express CD9. Thus, patients with a total CD9⁺ B cell frequency below 6.6% displayed significantly higher incidence of bronchiolitis obliterans syndrome (AUC = 0.836, PPV = 0.75, NPV = 1). These data are the first to associate IL-10-secreting CD24^hi CD38^hi transitional B cells expressing CD9 with better allograft outcome in lung transplant recipients. CD9-expressing B cells appear as a contributor to a favorable environment essential for the maintenance of long-term stable graft function and as a new predictive biomarker of bronchiolitis obliterans syndrome-free survival.

Atrial fibrillation is associated with hypermethylation in human left atrium, and treatment with decitabine reduces atrial tachyarrhythmias in spontaneously hypertensive rats

Atrial fibrillation (AF) is the most common cardiac arrhythmia. As the molecular mechanisms underlying the pathology are largely unknown, this cardiac arrhythmia remains difficult to treat. To identify specific molecular actors involved in AF, we have performed a transcriptomic analysis on left atrium (LA) from patients with valvular heart disease with or without AF. We showed that 1627 genes had altered basal expression level in LA tissue of AF patients compared with the control group. The significantly enriched gene ontology biological process "anatomical structure morphogenesis" contained the highest number of genes in line with changes in structure that occur when the human heart remodels following AF development (ie, LA dilatation and interstitial fibrosis). We then focused the study on Pitx2 (paired-like homeodomain 2), being the most altered transcription factor in LA from AF patients and from which compelling evidence have indicated that its reduced expression can be considered as a marker for the disease. In addition, its expression was inversely correlated with LA size. We demonstrated that AF is associated with Pitx2 promoter hypermethylation both in humans and arrhythmic aging spontaneously hypertensive rats. Chronic administration of a DNA methylation inhibitor (ie, 5-Aza-2'-deoxycitidine) improved ECG arrhythmic profiles and superoxide dismutase activities and reduced fibrosis in the left ventricle of spontaneously hypertensive rats. Taken together, these data support the notion that AF is associated with epigenetic changes in LA and provide a proof-of-concept that hypomethylating agents have to be considered in the treatment of atrial arrhythmias.

[Indications of lung transplantation: Patients selection, timing of listing, and choice of procedure]

Lung transplantation (LT) is now considered as an excellent treatment option for selected patients with end-stage pulmonary diseases, such as COPD, cystic fibrosis, idiopathic pulmonary fibrosis, and pulmonary arterial hypertension. The 2 goals of LT are to provide a survival benefit and to improve quality of life. The 3-step decision process leading to LT is discussed in this review. The first step is the selection of candidates, which requires a careful examination in order to check absolute and relative contraindications. The second step is the timing of listing for LT; it requires the knowledge of disease-specific prognostic factors available in international guidelines, and discussed in this paper. The third step is the choice of procedure: indications of heart-lung, single-lung, and bilateral-lung transplantation are described. In conclusion, this document provides guidelines to help pulmonologists in the referral and selection processes of candidates for transplantation in order to optimize the outcome of LT.

[Long-term results of lung cancer surgery in octogenarians]

INTRODUCTION

This retrospective study was undertaken to evaluate late results of lung cancer surgery in octogenerians.

METHODS

All patients 80years old or more who underwent a lung resection for cancer from 2000 to 2010 at Lyon University Hospital were included. No patients were treated with video-assisted surgery. Wedge resections were excluded.

RESULTS

Sixty-three patients (42 men, 21 women) were operated. The median age was 82years. Operative mortality was 4.7%. The rate of perioperative complications was 49%. The late survival was 34% at 5years. Five-year survival by nodal involvement was N0, 36%; N1, 29%; N2 20%, P<0.05. Patients with a squamous cell carcinoma (24) had a better long-term survival than patients with an adenocarcinoma (30), 33% and 25% respectively at 5years, P<0.05. The rate of recurrence was 33.9%.

CONCLUSIONS

Surgical treatment of lung cancer in selected population of octogenerians is associated with satisfactory early and long-term results. Survival is influenced by nodal involvement and by the pathologic type of the cancer.

Management of emerging multidrug-resistant tuberculosis in a low-prevalence setting

Multidrug-resistant (MDR) tuberculosis (TB) is an emerging concern in communities with a low TB prevalence and a high standard of public health. Twenty-three consecutive adult MDR TB patients who were treated at our institution between 2007 and 2013 were reviewed for demographic characteristics and anti-TB treatment management, which included surgical procedures and long-term patient follow-up. This report of our experience emphasizes the need for an individualized approach as MDR TB brings mycobacterial disease management to a higher level of expertise, and for a balance to be found between international current guidelines and patient-tailored treatment strategies.

[Management of tracheobronchial ruptures]

We report the case of a 25-year-old man who suffered a severe trauma with a complete rupture and separation of the right main bronchus. The patient presented on the scene with respiratory distress and severe hypoxemia. At the admission in the trauma resuscitation unit, the CT scan and fiberoptic examination confirmed the diagnosis of right main bronchus rupture. Selective fiberoptic intubation of the left main bronchus was done and the patient was sent to the operating theater for urgent thoracotomy. During thoracotomy, profound arterial oxygen desaturation requested the right main bronchus being intubated by the surgeon under the control of view and separate lung ventilation, until the end of the bronchus suture. Surgery allowed the patient to survive. He was then discharged alive from the hospital at day 36. Severe tracheobronchial rupture may be rapidly associated with major respiratory distress and severe hypoxemia that necessitate specialised care in referring centre. Initial orientation of these patients appears to be as important that airway and hypoxemia management.

Dorsalis pedis artery pseudoaneurysm: an uncommon cause of soft tissue mass of the dorsal foot in children

Pseudoaneurysm of the dorsalis pedis artery is an extremely rare entity with only 3 pediatric cases previously presented in the English literature. We describe a new case and discuss the clinical presentation and surgical management. A 6-year-old boy was referred to our clinic because of a pulsatile tumor of the right dorsal foot increasing in size. A focused history found a low grade trauma to the dorsal foot one year previously. Magnetic resonance imaging revealed a pseudoaneurysm of the DPA. Resection of the pseudoaneurysm was completed without complications. Pseudoaneurysm of the DPA is a very uncommon cause of soft tissue mass of the dorsal foot. It can appear after low grade trauma. Treatment is surgical.

Metachronous single lung transplantation after contralateral pneumonectomy. A ''big'' challenge?

Single lung transplantation for cystic fibrosis is an uncommon therapy. Contralateral pneumonectomy is, in these cases, rarely done before transplantation. Herein, we report the case of a single lung transplantation in a patient who had previously a contralateral pneumonectomy.

FDG-PET improves tumour detection in patients with paraneoplastic neurological syndromes

To determine the usefulness of [18F]fluorodeoxyglucose (FDG) whole body FDG-PET in the diagnosis of tumours in patients with paraneoplastic neurological syndromes (PNS), we prospectively studied 20 patients with paraneoplastic antibodies in whom conventional imaging gave negative or inconclusive results for the presence of tumour. All 20 patients had neurological manifestations compatible with PNS and well-characterized paraneoplastic antibodies (12 anti-Hu, one anti-Hu and anti-CV2, one anti-CV2, four anti-Yo, one anti-Ri and one anti-amphiphysin). The mean delay between the onset of neurological symptoms and FDG-PET was 10 months (range 1-54). In these 20 patients, abnormal uptake was demonstrated in 18 patients, with some patients having abnormal signal in several areas. We observed abnormal uptake in the mediastinum (13 cases), lung (two cases), breast (two cases), parotid gland (one case), or the cervical, supraclavicular or axillary lymph nodes (seven cases). Following FDG-PET, the histological diagnosis of the tumour was made in 14 patients (small cell lung carcinoma in eight cases, breast adenocarcinoma in two, lung adenocarcinoma in two, axillary metastasis of ovary carcinoma in one, and malignant thymoma in one). Two other patients with abnormal FDG uptake showed radiological evidence of lung cancer, but a histological diagnosis could not be obtained. In two other patients, initial FDG-PET showed abnormal FDG uptake that was not confirmed a few months later by repeat FDG-PET. In the two patients with negative FDG-PET, peritoneal carcinomatosis was diagnosed in one and no tumour was found in the other. In our series, the sensitivity of FDG-PET for tumour detection was >83% demonstrating a clear role of this technique in the management of patients with PNS. However, in our series, the specificity of FDG uptake was only 25% due to unexplained abnormal FDG uptake in three patients and in abnormal FDG uptake due to a benign tumour in one patient. Over the study period, we saw 73 other patients with PNS and paraneoplastic antibodies. A tumour was demonstrated in 71 out of 73 by conventional techniques. Since false-positive and false-negative results are possible with FDG-PET and in most patients with PNS, the tumour is demonstrated by conventional techniques, we believe that FDG-PET should be reserved, at the moment, for patients with well-defined PNS antibodies when conventional imaging fails to identify a tumour or when lesions are difficult to biopsy.

Bilateral internal thoracic artery harvesting under robotic video-assistance

BACKGROUND

Following upon the recent development of minimally invasive coronary robotic surgery, we set out to evaluate the feasibility of bilateral internal mammary artery (IMA) harvesting using the voice-controlled AESOP 2000 video assisted robot.

METHODS

The robot is placed on the right side of the patient. The left IMA is first totally video-harvested, with the arm of the robot crossing over the patient to reach the left chest. The voice-controlled movement of the arm allows the surgeon to obtain the best video image of the artery. After completion of the dissection, the arm is positioned on the right part of the chest. The right IMA is then harvested using the same technique.

RESULTS

Two patients underwent harvest of a bilateral IMA using this technique. The time of dissection was 52 min and 86 min, respectively.

CONCLUSION

This technique allows a more precise, faster, tremor-free dissection, as compared to a conventional thoracoscopic harvesting.

Role of matrix metalloproteinases in blood flow-induced arterial enlargement: interaction with NO

Tears in the internal elastic lamina (IEL) can be observed after chronic increases in arterial blood flow, suggesting a potential role for matrix metalloproteinases (MMPs) in flow-induced vascular remodeling. We undertook to study this phenomenon by constructing an arteriovenous fistula (AVF) between the left common carotid artery (CCA) and the external jugular vein in rabbits. The diameter of the flow-loaded left CCA increased by 13.6+/-1.8% by day 3 after construction of the AVF compared with the right CCA (n=4, P:<0.01) and by 40.7+/-7.5% by day-15 (n=10, P:<0.0001). Increased CCA diameter also coincided with IEL fragmentation. Three days after construction of the AVF, gelatin zymography of protein extracts from left CCAs of untreated rabbits showed a significant increase in the 62-kDa (active MMP-2) activity and the appearance of a lytic band at 92 kDa (pro-MMP-9). In further experiments, MMP activity was inhibited by treatment with doxycycline (DOX) or BB-94, a specific MMP inhibitor. The increase in the 62-kDa gelatinolytic band was abolished in DOX- and BB-94-treated rabbits. The 92-kDa gelatinolytic band was also reduced in DOX-treated animals. Furthermore, both increased left CCA diameter and IEL fragmentation were abolished in DOX- and BB-94-treated rabbits. To evaluate whether nitric oxide was involved in blood flow-induced MMP activation, the rabbits were treated with N:(G)-nitro-L-arginine methyl ester to inhibit nitric oxide synthesis. MMP activities were significantly decreased in the left CCAs of N:(G)-nitro-L-arginine methyl ester-treated animals. Hence, blood flow-induced MMP activation is critical in flow-induced vascular enlargement and IEL fragmentation, and blood flow-induced nitric oxide participates in MMP activation.

Better preservation of endothelial function and decreased activation of the fetal renin-angiotensin pathway with the use of pulsatile flow during experimental fetal bypass

OBJECTIVE

Pulsatile flow was shown to overcome the progressive rise in peripheral and placental vascular resistances observed during steady-flow bypass, this rise being counteracted by inhibition of nitric oxide synthase. This study quantifies the release of endothelial vasoactive substances during a 60-minute in utero model of fetal bypass.

METHODS

Fetuses were randomly allocated into 1 of 2 groups (steady flow, n = 8, or pulsatile flow, n = 13) and subjected to bypass through central cannulation and perfusion with either a centrifugal or pulsatile (125 beats x min(-1)) blood pump.

RESULTS

Lactate concentration was high, starting at fetal exteriorization and increasing during fetal preparation in the 2 groups. Once bypass was established, the rise was significant only in the steady-flow group. Plasma nitric oxide metabolites, similar before bypass, reached higher levels during pulsatile flow at the end of bypass (99+/-9 vs. 82+/-23 micromol x L(-1); P =.037). Levels of urinary nitric oxide metabolites were significantly higher in the pulsatile-flow than in the steady-flow group (764+/-143 vs. 508+/-240 micromol x L(-1); P =.005). Plasma cyclic guanosine monophosphate levels increased after 30 minutes of bypass in the pulsatile-flow group (25+/-18 vs. 12+/-8 pmol x mL(-1); P =.004), and urinary cyclic guanosine monophosphate excretion was higher in the pulsatile-flow group (517+/-450 vs. 118+/-78 pmol x mL(-1); P =.024). Plasma endothelin-1 levels increased in the 2 groups and were higher in the steady-flow group at 30 minutes (27+/-5 vs. 23+/-2 pg x mL(-1); P =.04) and 60 minutes of bypass (39+/-7 vs 32 +/- 6 pg x mL(-1); P =.04). Plasma renin concentration increased significantly during bypass only in the steady-flow group (26+/-10 vs. 57+/-42 in ng A1 x mL(-1) x h(-1); P =.04).

CONCLUSIONS

Improved placental and peripheral perfusion during fetal pulsatile-flow bypass may be mediated by preservation of fetal/maternal endothelial nitric oxide biosynthetic mechanisms and/or decreased activation of the fetal renin-angiotensin pathway.

Long-term results of sleeve lobectomy for lung cancer

OBJECTIVE

Sleeve lobectomy is a lung saving procedure indicated for central tumors for which the alternative is a pneumonectomy. Current controversies relate to the safety of the procedure and adequacy as a cancer operation. The aim of the study is to analyze long-term survival after sleeve lobectomy, particularly in relation with nodal status and histological type. The incidence and patterns of recurrences were reviewed.

METHODS

From 1972 to 1998, 184 patients (male 152, female 32) underwent sleeve resection for lung cancer. The mean age was 60+/-10 years (11-78 years), and the indications for operation were a central tumor (79%), peripheral tumor with nodal involvement (13%) and compromised pulmonary function (8%). The histological type was predominantly squamous (n=125, 68%), followed by non-squamous (n=50, 27%) and carcinoid tumors (n=9, 5%). Resection was complete in 161 patients (87%).

RESULTS

The operative mortality was 1.6% (n=3). Follow-up was complete for the remaining 181 patients (mean, 5.7 years; range, 1 month-26 years). The survival at 5 and 10 years of all patients was 52 and 33%, respectively. Theses rates for patients with N0 status (n=97) were 63 and 48%, and 48 and 27% for those with N1 status (n=68; N0 vs. N1, P<0.05). An 8% survival rate was observed with N2 status (n=19) at 5 years, with no survivors after 7 years of follow-up. The 5 and 10 year survival was 56 and 34% for squamous carcinoma vs. 33 and 22% for non-squamous carcinoma (P<0.05). These rates were 58 and 38% for complete resection vs. 11 and 6% for incomplete resection at 5 and 10 years, respectively (P<0.05). Local recurrences occurred in 22% of cases, and the prevalence was statistically different between patients with N0 disease (14%) and N1 disease (23%; P=0.03), but not between N1 and N2 disease (42%; P=0.2). When local and distant recurrence were pooled together, the differences were highly significant between N0 (22%) and N1 (41%) disease (P=0.007), and between N0 and N2 (63%) disease (P=0.0002), but not between N1 and N2 disease (P=0.09).

CONCLUSION

Sleeve lobectomy is a safe and effective therapy for patients with resectable lung cancer. The presence of N1 and N2 disease, or of non-squamous carcinoma significantly worsen the prognosis.

The left retro-aortic brachiocephalic vein: morphologic data and diagnostic ultrasound in 27 cases

A left retro-aortic brachiocephalic vein is a rare anatomic entity. A retrospective study was made of 5218 congenital cardiopathies treated between 1982 and 1998 in a medico-surgical department of paediatric cardiology. A left retro-aortic brachiocephalic vein was demonstrated in 27 patients, i.e. an incidence of 0.5%. The chief cardiopathy in these patients was a tetralogy of Fallot in 25 cases (93%). Among these 25 cases of Fallot's tetralogy the aortic arch was rightsided in 19 cases (70%). The paraclinical diagnosis of this anomaly was facilitated by ultrasonography, provided it was sought for. In this series 6 cases (22%) were discovered during surgery without previous ultrasound diagnosis. The embryological origin of the left retro-aortic brachiocephalic v. differs from that of the venous trunk in its classical anatomic form. It derives from the inferior (but not superior) transverse plexuses, connecting the two anterior cardinal veins. One of the main consequences of this anomaly is its possible confusion with other vascular structures, particularly the right pulmonary artery. Such confusion may give rise to inappropriate surgical procedures. The differential diagnosis is facilitated by the use of the Doppler: the venous flow is biphasic and regulated by respiration, whereas the Doppler recording from a pulmonary artery is that of a characteristic systolic arterial flow.

Video-assisted tricuspid valve surgery: a new surgical option in endocarditis on pacemaker

A patient presenting with a pacemaker lead infection and tricuspid regurgitation underwent a minimally invasive video-assisted tricuspid valve replacement. The valve was approached through a right anterior mini thoracotomy. Under thoracoscopic vision and peripheral cardiopulmonary bypass, a catheter was placed on the ascending aorta for antegrade cardioplegia delivery. A transthoracic aortic cross-clamp was introduced through the third right intercostal space. Tricuspid valve replacement added to the pacemaker leads ablation was exclusively performed under thoracoscopic vision, providing an excellent video-image in this reduced operative field. After 22 months of follow up, the patient is asymptomatic, the echocardiography showing a normally functioning valve.

[Chest wall tumors. Report of 17 cases]

The aim of this work was to evaluate the different approaches to surgical repair of the thoracic wall and to discuss technical indications. From June 1987 to June 1997, we cared for 17 patients, 14 males (82.3%) and 3 females (17.7%) with parietal neoplasia. All patients underwent a preoperative respiratory work-up to identify tumoral extension. In 6 patients, the morphology and location of the tumor led to CT-guided transthoracic needle aspiration. Tumoral excision in 14 patients (82.3%) included wide resection of osteomuscular structures. Reconstruction of the thoracic wall associated myoplasty in all cases. A prosthesis was installed in 5 cases and a rib transposition in 2. Pathology examination of the surgical specimen revealed 13 primary tumors (76.5%) and 4 secondary tumors (23.5%) CT-guided transthoracic needle aspiration confirmed the diagnosis in 82.2% of the cases. Twelve patients (70.5%) were alive and recurrence free at 85.6 +/- 40 months after surgery. Five patients died (29.5%) 12.2 +/- 10.1 months after surgery. There was one case of prosthesis infection (5.8%). The appropriate choice of the surgical technique and repair materials gave satisfactory oncological, esthetic and functional results independently of the extent of the parietal defect.

Techniques of pneumonectomy. Completion pneumonectomy

Completion pneumonectomy refers to an operation intended to remove what is left of a lung partially resected during previous surgery. Completion pneumonectomy is a technically demanding procedure, which carries an increased operative mortality and morbidity. If the planning and the surgical technique are done meticulously, the good prospect for long-term survival justifies the higher risk.

Physiologic consequences of pneumonectomy. Consequences on the pulmonary function

When pneumonectomy is done in children, there is some speculation that lung growth occurs. In the adult population, volume response is incomplete and attributable to alveolar distention rather than multiplication. Stretch is widely regarded as the initial stimulus for compensatory growth. The authors review data pertaining to the physiology of the various adjustments that occur after pneumonectomy gathered both from observations on human response and from experimental findings in animals. Mechanisms and mediators of this adaptive response are discussed.

Long-term clinical and hemodynamic evaluation of porcine valved conduits implanted from the right ventricle to the pulmonary artery

OBJECTIVE

This retrospective study was initiated to evaluate the long-term results of valved prosthetic conduits implanted in the right ventricular outflow tract in patients with complex ventricular-pulmonary discontinuity.

METHODS

A cohort of 103 patients out of 127 (24 early deaths, 19%) operated on between 1973 and 1996 with porcine valved conduits was available for evaluation, with a follow-up ranging from 1 to 21.6 years (mean follow-up 8.4 +/- 6 years). A total of 74 hemodynamic studies were performed after the operation, 50 patients having undergone at least 1 cardiac catheterization during the follow-up period.

RESULTS

There were 16 late deaths, and the actuarial survivals, including early mortality, were 72.9% +/- 4% at 5 years, 63.1% +/- 5% at 10 years, and 58.2% +/- 5% at 15 years, at which time 20 patients were still available for review and exposed to the risk of dying. The mean peak systolic gradient across the right ventricular outflow tract was plotted as a function of time, showing a gradual increase and a significant step-up after the eighth year, from 43 +/- 36 to 69 +/- 19 mm Hg (P < .005). Reoperation was required for progressive conduit obstruction between 1.1 and 17.7 years after implantation (mean 7.4 +/- 4.8 years) in 25 patients (24%, 70% CL 15%-33%), with generally very few symptoms, or for residual ventricular septal defect in 3 patients. Freedom from reoperation was 79.5% +/- 5% at 10 years and 65.8% +/- 7% at 15 years.

CONCLUSIONS

Porcine conduits may represent a valuable alternative to biologic substitutes with similar long-term results. Given the few symptoms, progressive conduit stenosis after the eighth postoperative year imposes a yearly noninvasive patient evaluation during the follow-up.

Effects of various flow types on maternal hemodynamics during fetal bypass: is there nitric oxide release during pulsatile perfusion?

OBJECTIVE

This study investigates the role of various flow conditions on maternal hemodynamics during fetal cardiopulmonary bypass.

METHODS

Normothermic fetal bypass was conducted under pulsatile, or steady flow, for a 60-minute period. Fetal lamb preparations were randomly assigned to 1 of the 3 groups: steady flow (n=7), pulsatile flow (n=7), or pulsatile blocked flow bypass (n=7), where fetuses were perfused with Nomega-nitro-L-arginine after the first 30 minutes of pulsatile flow to assess the potential role of endothelial autacoids.

RESULTS

Maternal oximetry and pressures remained unchanged throughout the procedure. Under fetal pulsatile flow, maternal cardiac output increased after 20 minutes of bypass and remained significantly higher than under steady flow at minute 30 (8.8+/-0.7 L x min(-1) vs 5.9+/-0.5 L x min(-1), P=.02). Maternal cardiac output in the pulsatile group also remained higher than in both steady and pulsatile blocked flow groups, reaching respectively 8.7+/-0.9 L x min(-1) vs 5.8+/-0.4 L x min(-1) (P=.02) and 5.9+/-0.3 L min(-1) (P=.01) at minute 60. Maternal systemic vascular resistances were significantly lower under pulsatile than under steady flow after 30 minutes and until the end of bypass (respectively, 9.1+/-0.6 IU vs 12.7+/-1.1 IU, P=.02 and 8.9+/-0.5 IU vs 12.9+/-1.2 IU, P=.01). Infusion of Nomega-nitro-L-arginine was followed by an increase in systemic vascular resistances from 9.3+/-0.7 IU, similar to that of the pulsatile group, to 13.5+/-1 IU at 60 minutes, similar to that of the steady flow group.

CONCLUSIONS

Maternal hemodynamic changes observed under fetal pulsatile flow are counteracted after infusion of Nomega-nitro-L-arginine, suggesting nitric oxide release from the fetoplacental unit under pulsatile fetal flow conditions.

Experimental right ventricle to pulmonary artery discontinuity: outcome of polyurethane valved conduits

OBJECTIVE

The ideal substitute for the treatment of ventricle-pulmonary artery discontinuity remains a topic of controversy, because of calcifications and degeneration of biologic substitutes leading to subsequent reoperations. Because polyurethane valves used in ventricular assist devices show a satisfactory biocompatibility, the aim of this study was to evaluate a valved conduit composed of a Dacron graft incorporating a trileaflet 25 mm polyurethane valve.

METHODS

The conduit was implanted between the right ventricle and the main pulmonary artery in adult sheep, with ligation of the proximal pulmonary artery. The animals received no medications. Serial hemodynamic data were collected at the time of implantation and at postoperative intervals of 6 and 12 months.

RESULTS

The peak pressure gradient across the valve increased significantly between implantation (0.17 +/- 5.6 mm Hg) and 6 months after operation (7.3 +/- 3 mm Hg, p = 0.0007) and remained stable thereafter (6.7 +/- 3 mm Hg at 12 months), whereas the cardiac output remained unchanged (4.6 +/- 0.6 L/min at implantation, 4 +/- 0.6 L/min at 6 months, and 3.9 +/- 1.1 L/min at 12 months). At the completion of the study, valve samples were processed and vapor coated with carbon for microscopic examination. There was one instance of nonadherent thrombus formation inside a cusp but no structural failures. The other valves were free of calcium deposits and no significant amounts of phosphorus could be detected by scanning electron microscopy and energy dispersive spectrometry.

CONCLUSIONS

These data demonstrate the good hemodynamic performance, low thrombogenicity, and acceptable durability of the polyurethane valves implanted in the right side of the heart in a chronic sheep model.

Mechanical versus biological isolated aortic valvular replacement after the age of 70: equivalent long-term results

OBJECTIVE

In order to evaluate the long-term outcome of valvular substitutes in the elderly, we retrospectively analyzed two comparative groups of patients consecutively operated on by the same team for an isolated valvular aortic replacement using either a mechanical or a pericardial prosthesis.

METHODS

From 1982 to 1996, 206 patients over 70 years (mean 76.5+/-4.4) underwent an isolated aortic valvular replacement using either a St. Jude Medical (Group I, n = 93) or a Mitroflow (Group II, n= 113) prosthesis depending on the surgeon's preference at the time of surgery. Both groups matched for the following pre-operative variables: sex ratio, type of aortic valve disease, NYHA status, cardiac rhythm, mean pulmonary arterial pressure, left ventricular end-diastolic pressure, LV-AO gradient, cardiac index and ejection fraction.

RESULTS

Given an early mortality rate of 6.4% in Group I and 4.4% in Group II (NS), follow-up (mean 4.4+/-3.7 years in Group I and 5.3+/-3.1 years in Group II) was 100% complete. Actuarial survival was 69.9+/-6 and 70.2+/-4.6% at 5 years for Group I and Group II, respectively, and 49.6+/-7.7 vs. 51.4+/-6.3% at 10 years (NS). Freedom from valve-related death was 86.5+/-4.8% in Group I vs. 82.7+/-4% in Group II at 5 years (NS) and 66.7+/-8.7 vs. 66.3+/-7% at 10 years (NS). There were no anticoagulant-related deaths or severe accidents in Group 1. A secondary valvular replacement was necessary in 4 patients in Group II vs. none in Group I.

CONCLUSION

The study shows a similar late survival in both groups, with a strikingly low incidence of anticoagulant-related deaths in this population. Given a higher rate of reoperation after biological valve replacement, the use of mechanical valve in this aging population seems to be a valid option.

[Coarctation of the aorta and its surgical treatment]

Coarctation or isthmic stenosis of the aorta is defined as an abnormal obstruction situated at the junction of the aortic arch and the descending aorta near the site of ligamentus arteriosus. It is a common malformation representing 5 to 7.5% of all congenital heart diseases. Coarctation of the aorta is 2 to 3 times commoner in boys than in girls. Two clinical forms may be distinguished: asymptomatic isolated coarctation of childhood, the surgical treatment of which was first performed by Crafoord in 1944, and coarctation of the neonate and infant associated in over 2/3 of cases with other cardiovascular malformations, especially tubular hypoplasia of the aortic arch. The surgical correction of isolated coarctation is best performed between 6 months and 1 year of age in other to limit the incidence of residual hypertension. A modified Crafoord technique decreases the risk of restenosis and enables treatment of associated hypoplasia of the aortic arch in the same surgical procedure.

Flow-induced release of endothelium-derived relaxing factor during pulsatile bypass: experimental study in the fetal lamb

OBJECTIVE

This study was initiated to test the hypothesis that fetal hemodynamic changes observed under pulsatile flow bypass might be related to the release of endothelium-derived relaxing factor through oscillating shear stress.

METHODS

Normothermic bypass was instituted in utero in 21 preterm fetal lambs for a 1-hour period through the right atrium and main pulmonary artery. Ultrasonic flowmeters were positioned around the descending aorta and the umbilical artery. The circuit consisted of an oxygenator and a pump set to either continuous flow (n = 7) or pulsatile flow (n = 7) and adjusted to maintain a fetal main arterial pressure of 50 mm Hg. In seven other animals, endothelium-derived relaxing factor was blocked by a continuous infusion of N omega-nitro-L-arginine after 30 minutes of pulsatile flow.

RESULTS

During the first 30 minutes of bypass, pump flows were significantly lower in the continuous-flow group than in the pulsatile-flow or blocked-flow groups (respectively, 612 +/- 144, 907 +/- 153 and 987 +/- 228 ml/min), with similar changes in aortic and umbilical flows. Systemic vascular resistances were significantly lower in the pulsatile-flow and blocked-flow groups than in the continuous-flow group (550 +/- 106 vs 821 +/- 212 dynes/sec/cm-5). However, after blockade of endothelium-derived relaxing factor, resistances increased gradually in the blocked-flow group to reach the level of that of the continuous-flow group at the end of bypass (943 +/- 77 vs 556 +/- 143 dynes/sec/cm-5 in the pulsatile-flow group).

CONCLUSIONS

Blockade of endothelium-derived relaxing factor after 30 minutes of pulsatile flow returns fetal hemodynamics to continuous flow conditions. The specific inhibitor of endothelium-derived relaxing factor used in this experiment suggests that nitric oxide may be released by fetal endothelium during pulsatile bypass.

Malignant neoplasms following cardiac transplantation

OBJECTIVE

Malignancies have long been recognized as a complication of long lasting immunosuppressive therapy. We reviewed our experience to investigate the incidence and the spectrum of non cutaneous de novo malignant neoplasms.

METHODS

Between March 1987 and March 1996, 296 patients underwent 303 cardiac transplantation in our service. The population at risk consists of all patients surviving more than 1 month after transplantation, leading to a total of 267 patients. A triple-immunosuppressive therapy was employed. Moderate doses of antilymphocyte globulin was used as an induction immunotherapy.

RESULTS

Neoplasms developed in 18 (6.7%) of the 267 patients at risk. Seventeen patients were male. Mean age was 56 +/- 7 years. Fourteen patients (78%) reported a significant smoking history. Mean interval between transplantation and clinical diagnosis was 36 months. Lung neoplasms (especially adenocarcinoma) were the most commonly encountered tumors (11 of 268 patients, 4.1%). Three Non-Hodgkins' Lymphoma (NHL) were identified (1.1%). No Kaposi's sarcoma were diagnosed. Mean survival after a diagnostic of tumor was 11.7 months.

CONCLUSIONS

The incidence of NHL is low in our transplant recipients. Conversely, we observed a high incidence of lung neoplasms (especially adenocarcinoma) which can be correlated with a heavy cigarette use in the study population.

[Left ventricular assistance by postoperative mechanical devices in neonates]

Circulatory assistance in children and neonates has not been extensively reported. It poses specific problems related mainly to miniaturisation of systems. The authors report three cases of left ventricular assistance with the Biomedicus centrifugal pump followed by functional recovery in neonates operated for d-transposition of the great arteries. The assistance was installed by cannulation of the left atrial appendage and the ascending aorta, the canules being connected to the Biomedicus pump. The duration of assistance was 53, 116 and 120 hours respectively. The beginning of left ventricular recovery was observed after 24, 48 and 70 hours of assistance and the patients were weaned of assistance under stable haemodynamic conditions. One of the major problems during the period of assistance is decoagulation, 2 out of 3 patients requiring removal of thrombi during the first 12 hours of assistance. On the other hand, no cases of systemic embolism or thrombosis in the pump itself were observed. Decoagulation was maintained by continuous intravenous heparin with an initial dosage of 5 U/kg/h adapted to the activated cephalin time and anti Xa levels measured every 6 hours. No infectious complication was observed and the sternal wound healed satisfactorily despite systematic delayed closure of the thorax. The quality of results requires cooperation of a surgical infrastructure used to techniques of circulatory assistance, a well equipped neonatal intensive care unit and a permanently accessible laboratory for monitoring coagulation status.

Mechanical valve in aortic position is a valid option in children and adolescents

OBJECTIVE

The choice of a valve substitute remains a challenge in young patients, with numerous reports of early degeneration and calcification of biological valves in this age group. Therefore an assessment of the long-term results after mechanical aortic valve replacement in children was initiated.

METHODS

A retrospective study was conducted in 54 consecutive patients aged 1.1 to 17 years (mean 12.8 +/- 4 years) operated on between 1975 and 1993. Aetiology was congenital in 34 patients, rheumatic in 13, infectious in 5, and dystrophic in 2. Concomitant surgery included mitral valve replacement (10), aortic annulus enlargement (9), correction of truncus arteriosus (7), Bentall operation (2), coarctation repair (2), tricuspid valvuloplasty (2), correction of double outlet right ventricle (1), and replacement of a right ventricle to pulmonary artery conduit (1). A Bjork-Shiley valve was implanted in 14 patients, and a St Jude Medical valve in 40. All patients were given Warfarin with a monthly INR control. Follow-up was completed through questionnaires mailed to referring physicians and direct clinical examination.

RESULTS

Overall early mortality was 13% (7 cases), and 6% (2 cases) in the 32 patients operated on after 1984. Follow-up was complete in 45 survivors (2 lost to follow-up), with a total follow-up of 261 patient-years. There were 6 late deaths, 4 being cardiac and due to persistent LV dysfunction, and 2 valve-related, due respectively to major gastro-intestinal bleeding and massive thromboembolism. Linearized rates of valve thrombosis and anticoagulant-related hemorrhage were both 0.3% per patient-year. Actuarial survival rate was respectively 84.5% at 5 years and 70.2% at 10 years. Reoperation was necessary in 3 patients for recurrent LV outflow tract obstruction. One patient with severe LV dysfunction is awaiting a heart transplant.

CONCLUSION

We conclude that the longterm outcome after mechanical aortic valve replacement in children and adolescents is satisfactory and comparable to currently available reports on biological substitutes. The mandatory anticoagulant therapy is well tolerated in this age group.

Role of NO in flow-induced remodeling of the rabbit common carotid artery

Flow-induced changes in vessel caliber tend to restore baseline wall shear stress (WSS) and have been reported to be endothelium-dependent. To investigate the role of endothelium-derived nitric oxide (NO) in the adaptive increase in artery diameter in response to a chronic increase in blood flow, an arteriovenous fistula was constructed between the left common carotid artery (CCA) and the external jugular vein in 22 New Zealand White rabbits, and NO synthesis was inhibited in 14 animals by long-term administration of NG-nitro-L-arginine-methyl ester (L-NAME) in drinking water given for 4 weeks. The remaining 8 animals served as controls. Mean arterial blood pressure was not significantly altered by L-NAME treatment (91 +/- 2 in control versus 98 +/- 3 mm Hg in L-NAME-treated rabbits). Blood flow significantly increased in the left CCA in both groups but was lower in L-NAME-treated than control animals (106.1 +/- 10.7 versus 196.2 +/- 32.3 mL/min, P < .003). The diameter of the flow-loaded left CCA also increased significantly in both groups compared with the right CCA (2.15 +/- 0.12 and 2.54 +/- 0.1 mm, respectively, P < .02), but the increase was less in the L-NAME-treated than the control group (3.24 +/- 0.09 and 4.64 +/- 0.17 mm, respectively, P < .0001). The diameter of the anastomosed veins was also increased but to a much lesser degree in L-NAME-treated animals than in controls (4.14 +/- 0.29 versus 7.94 +/- 0.51 mm, P < .0001). As a result of artery enlargement, WSS was normalized in the flow-loaded left CCA of the control group (8.87 +/- 0.77 dynes/cm2) regardless of blood flow values. In L-NAME-treated animals, however, WSS was only partially regulated, the mean value being significantly increased (18.7 +/- 2.2 dynes/cm2, P < .006). Moreover, a highly significant positive correlation between WSS and blood flow was obtained in L-NAME-treated animals (r = .84, P < .0001). We also found remodeling of the artery wall, with a larger increase in the medial cross-sectional area associated with an increased number of smooth muscle cells, in the control group compared with the L-NAME-treated group (0.75 +/- 0.09 versus 0.49 +/- 0.04 mm2 and 4504 +/- 722 versus 2717 +/- 282 cells/mm2, P < .03). We conclude that NO plays a role in the increase of vessel caliber in response to chronic increase in blood flow. As yet unidentified additional metabolic processes appear to be necessary for a complete regulatory response.

Primary melanoma of the heart: case report of an association with coronary stenosis

A 63-year-old man presented with unstable angina. The coronary angiogram revealed a proximal left anterior descending artery (LAD) stenosis and an irregularity on the anterior wall of the left ventricle. Intraoperatively, a malignant melanoma, independent of the coronary stenosis, was identified and resected, and an internal mammary graft was inserted. No primary tumor was found. The patient is alive 18 months after operation, with a normal magnetic resonance imaging (MRI), which seems to be the technique of choice for following-up heart melanomas.