Patrick von Samson

Percutaneous Edge-to-edge Repair of Tricuspid Regurgitation in Congenitally Corrected Transposition of the Great Arteries

A 62-year-old woman presented with shortness of breath and NYHA III. Severe heart failure was due to reduced systolic function. The woman reported of lung edema at two times. Computed tomography scan and magnetic resonance imaging showed a congenitally corrected transposition of the great arteries (CC-TGA). Echocardiographic findings revealed a high grade tricuspid regurgitation. For treatment of the tricuspid regurgitation, we used a percutaneous approach. The Evalve MitraClip(®) system has demonstrated feasibility and safety in the treatment of mitral regurgitation. Three months after successful tricuspid valve clipping, the patient is fine and NYHA score is reduced to grade I.

Comparison of protein with DNA therapy for chronic myocardial ischemia using fibroblast growth factor-2

OBJECTIVE Treatment of coronary disease by growth factors has become an increasingly used strategy for otherwise untreatable patients and is subject to a number of clinical studies. The aim is to stimulate the development of a sufficient collateral circulation and hereby to rescue cardiac function. The objective of our study was to compare the effectiveness of fibroblast growth factor-2 (FGF-2) as protein and as naked plasmid DNA in a porcine model of chronic myocardial ischemia. MATERIALS AND METHODS A severe stenosis of the left anterior descending artery (LAD) artery was created in healthy pigs. After 1 week, perfusion and regional and global contractility was assessed at baseline at rest and under stress. Afterwards, recombinant FGF-2 (n=6) or naked plasmid DNA encoding FGF-2 (n=7) was intramyocardially injected into the LAD territory. Control animals were left untreated (n=5). After 3 months, the animals were re-examined and underwent immunohistologic analysis. One animal received an Enhanced Green Fluorescent Protein plasmid. RESULTS Plasmid-dependent protein synthesis was present in cardiomyocytes. FGF-2 protein as well as plasmid injections resulted in an increased number of capillaries and of arterioles compared with untreated ischemia. The improvement of the regional myocardial blood flow by FGF-2 plasmid therapy at rest might however indicate the effectiveness of the DNA application for the induction of a collateral circulation. A benefit from FGF-2 plasmid therapy was revealed with regard to regional contractility. Systemic hemodynamics were partially improved following plasFGF-2 treatment. CONCLUSIONS In this porcine model of chronic myocardial ischemia, intramyocardial injection of FGF-2 plasmid was more effective than of FGF-2 protein in improving regional perfusion and contractility compared to untreated ischemia.

Transmyocardial laser revascularization combined with vascular endothelial growth factor121 (VEGF121) gene therapy for chronic myocardial ischemia – do the effects really add up?

OBJECTIVE Different therapy strategies for coronary disease in conventionally untreatable patients have been developed, among them transmyocardial laser revascularization (TMLR) and the application of growth factors. The objective of our study was to determine whether a combined therapy of TMLR with a vascular endothelial growth factor(121) (VEGF(121)) plasmid is able to stimulate the development of sufficient collateral circulation and hereby to preserve cardiac function. MATERIALS AND METHODS A severe stenosis of the left anterior descending artery was created in healthy pigs. After 1 week, perfusion and regional contractility were assessed at baseline. Afterwards, the ischemic area was treated with TMLR (n=8), intramyocardial injection of naked plasmid DNA encoding VEGF(121) (n=7), or both (n=7). Control animals were left untreated (n=8). After 3 months, the animals were re-examined and underwent immunohistological analysis. RESULTS The number of capillaries increased only after injection of VEGF(121) plasmid alone compared to untreated ischemia and to the other therapy groups, whereas the number of arterioles was higher following TMLR treatment alone or in combination with VEGF(121) than it was in the case in untreated ischemic animals. However, only combined VEGF(121)+TLMR therapy resulted in an improvement in regional myocardial blood flow in comparison with 1 week ischemia, indicating the efficient development of collateral circulation. In contrast, better regional contractility compared to the 1-week baseline, as well as restoration of the pre-ischemic values, were achieved by both VEGF(121) and combined VEGF(121)+TLMR therapies. CONCLUSIONS This study of chronic myocardial ischemia with a porcine model indicates a synergistic action of TMLR and VEGF(121) gene therapy. Combined treatment alone achieved an increase of regional myocardial perfusion, which accompanied arteriogenesis and corresponded with the restoration of regional function.

Microperfusion enhancement after TMLR in chronically ischemic porcine hearts.

OBJECTIVE The purpose of this study was to determine the effect of transmyocardial laser revascularization (TMLR) on myocardial perfusion and function in chronically ischemic myocardium. METHODS In the first operation a stenosis of the left anterior descending artery was created in 20 open-chest anesthetized pigs to implement this ischemic model. In contrast, four pigs served as controls (thoracotomy only). Seven days later (2nd operation), all animals were studied at baseline by analyzing different parameters of perfusion (radioactive microspheres), function, and intramyocardial pressure. Afterwards, pigs who received a left anterior descending artery stenosis were randomized into one of three groups: animals in laser group 1 (n=7) received one and in laser group 2 (n=7) two laser channels per cm(2) in the left anterior descending artery territory. Animals of the ischemic group (n=6) underwent the same procedures without transmyocardial laser revascularization. Three months later, the animals were re-studied (3rd operation) and additional analysis of histochemistry and myocardial water content was performed. RESULTS Regional myocardial blood flow (RMBF) in laser group 2 revealed statistically higher RMBF values compared to the ischemic group (0.39+/-0.13 versus 0.14+/-0.12 ml/min/g; P=0.043), after 3 months, whereas the absolute RMBF had not increased compared to the 1-week baseline values. Left ventricular stroke work index (LVSWI) at rest and under stress did not show any improvement compared to the initial values in all study groups (P=ns). Nevertheless, laser group 1 demonstrated relatively higher LVSWI(max) values compared to the ischemic (1.33+/-0.19 versus 0.93+/-0.16 mJ/kg; P=0.03) and laser group 2 (1.33+/-0.19 versus 1.02+/-0.15; P=0.024). Regional contractility of laser groups 1 and 2 recovered after 3 months (which had deteriorated shortly after transmyocardial laser revascularization) and increased under stress (100% versus 144.33+/-46.42, P=0.029 and 100% versus 116.26+/-21.06, P=0.034; respectively). In contrast, the corresponding ischemic group values were not different from initial values (P=ns). CONCLUSIONS This model of chronic regional ischemia demonstrates that CO(2)-laser revascularization significantly improves microperfusion and regional function, whereas the overall perfusion and global LV function is unchanged.

Surgical Technique of Lower Lobe Lung Transplantation

Among patients with end-stage lung disease awaiting lung transplantation, pediatric and small adult patients have a significantly lower chance of getting size-matched pulmonary grafts in time because of the severe scarcity of small donors. It is our strategy to perform lobar lung transplantations in small recipients with restrictive pulmonary disease once their clinical status demands urgent transplantation. Here we describe our surgical technique and discuss the benefits and risks of this procedure.

Evaluation of the indirect revascularization method after 3 months chronic myocardial ischemia

OBJECTIVE The long-term effectiveness of transmyocardial laser revascularization (TMLR) was evaluated in the setting of a severe left anterior descending artery (LAD) stenosis. METHODS To employ the chronic ischemic model, pigs underwent three operative procedures over a 13-week period. In the first operation, an operative stenosis of the LAD was created. One week later, the animals were studied at baseline by analyzing different parameters of perfusion (microspheres), function and ECG changes. Afterwards, pigs were randomized into one of three different experimental groups: animals in laser group 1 received one laser channel (n=9) and laser group 2 two channels per cm(2) (n=6) in the LAD territory (using a CO(2)-laser). Animals of the ischemic group (n=12) underwent the same procedures without TMLR-treatment. Twelve weeks later, the animals were re-studied (third operation) and killed. Additional analysis of myocardial water content and histochemistry was performed. RESULTS Chronic myocardial ischemia and regional myocardial blood flow (RMBF) in laser group 2 revealed relatively higher RMBF values compared with the ischemic group (P=0.015), after 3 months, but no absolute improvement of perfusion at rest compared with baseline was observed in all experimental groups. Left ventricular stroke work index (LVSWI) at rest and under stress did not show any improvement compared with initial values in all study groups (P not significant). However, laser group 1 demonstrated relatively higher LVSWI(max) values in comparison with the ischemic group (P=0.013) as did laser group 2 (P=0.017). Regional contractility of the laser groups recovered after 3 months (which was deteriorated shortly after TMLR, P<0.001) and increased under stress compared with baseline (laser 1: P=0.015, laser 2: P=0.017). In contrast, the ischemic group did not show any difference from initial values (P not significant). The lased pigs of group 2 were less prone to intractable ventricular fibrillation (P=0.036 vs. ischemic group), and showed a significant smaller area of necrosis in the area at risk (P=0.012 vs. ischemic group). CONCLUSIONS This model of chronic regional ischemia demonstrates that CO(2)-laser revascularization significantly ameliorates microperfusion and regional contractility, and diminishes the incidence of ventricular fibrillation and necrosis in the area at risk. However, it does not change the overall perfusion and global LV function.

The Impact of Shunt Type on Palliative Outcomes in Neonates and Infants With Diminished Pulmonary Blood Flow

We analyzed early and intermediate outcomes in cyanotic neonates (n = 43) and infants (n = 26) requiring palliation with either a modified Blalock-Taussig shunt (MBT) or a central aortopulmonary shunt (CAP). Between 1995 and 2009, 69 consecutive patients underwent an MBT (n = 42) or CAP (n = 27) for tetralogy of Fallot (n = 21), pulmonary atresia (n = 25), severe pulmonary valve stenosis (n = 22), and 2-stage repair of transposition of the great arteries (n = 1). The groups were similar with regard to age, weight, pulmonary artery diameter, and preoperative saturations. Postoperative mortality was 3 after CAP (11.1%) versus 1 after MBT (2.4%; P = .0203). Shunt size/weight index was comparable for both groups. MBTs had shorter surgical times (P = .002), required less inotropes (inotropic index, 103 ± 18 vs 889 ± 199; P = .0069), less blood product transfusions (P = .01), and had shorter duration of ventilation (P = .026) and intensive care unit (ICU) stay (P = .042). Children with MBTs had higher saturations at hospital discharge (P = .018). Prior to complete repair, 2 patients with a CAP and 10 patients after an MBT needed pulmonary artery dilation or stent implantation (P = .23). At the time of complete repair and shunt takedown, 3 MBT patients needed surgical patch augmentation of the pulmonary artery. The MBT is a safer and more expeditious operation and more frequently avoids cardiopulmonary bypass. Patients require less inotropes, blood products, and ICU time but may require more interventional therapy to treat pulmonary artery stenosis in the interval to complete repair. Surgical treatment of shunt-related pulmonary artery distortion may be addressed at the time of complete repair.

Transgenic and transmural revascularization: regional myocardial tissue pressure during chronic ischemia

Channel patency and a cavito-myocardial pressure gradient are prerequisites for one potential mechanism of transmyocardial laser revascularization (TMLR), namely indirect (non-coronary) myocardial perfusion. We assessed the effect of TMLR combined with vascular endothelial growth factor (VEGF) on the myocardial tissue pressure (MTP) in chronic ischemia questioning firstly, whether transmural pressure allows perfusion of laser channels, and secondly, whether additional application of VEGF improves channel patency. One week after creation of an operative left anterior descending artery stenosis (2nd operation), pigs were designated to untreated ischemia (n=7), TMLR (n=8) or TMLR+VEGF-cDNA (2 mg intramyocardially, n=6). MTP and left ventricular pressure (LVP) were recorded simultaneously in the endo-, mid-, and epimyocardium before and after stenosis (1st operation), before and after therapy (2nd operation), and 12 weeks later (3rd operation). Myocardial samples were subjected to immunohistochemistry. Endo- and epimyocardial MTP exceeded LVP in all groups throughout the study, whereas midmyocardial MTP was constantly below LVP (P<0.05). Immediately after combined TMLR+VEGF, the endo-MTP decreased from 246.5+/-44.2 to 176.7+/-20.7 mmHg (P=0.043), remaining higher than LVP. After 12 weeks, it increased to 225.6+/-31.8 mmHg (P=0.04), but did not reach baseline values (P=0.04). Histological examination revealed occluded channels with surrounding vascular proliferation in both treatment groups. Additional VEGF-cDNA application in the vicinity of TMLR channels does not improve long-term patency. Direct blood flow from the cavity into the myocardium is impossible due to the high endomyocardial pressure. This limitation might be overcome by implantation of endomyocardial stents.

Evozierte Potentiale in der Aortenchirurgie

ZusammenfassungEinleitungDieser Artikel beschreibt das Anlegen von Elektroden, die der Überprüfung der neurophysiologischen Funktionsfähigkeit des Rückenmarks bei Operationen an der thorakalen und thorakoabdominellen Aorta dienen.MethodenDas intraoperative Monitoringverfahren umfasst die Aufzeichnung sowohl somatosensorisch evozierter Potentiale (SSEP) als auch motorisch evozierter Potentiale nach transkranieller elektrischer Stimulation (tcMEP). Für die Messung der tcMEP werden die Stimulationsnadeln mittels subkutaner Elektroden an Position C3 und C4 entsprechend des 10–20–Systems für EEGAufzeichnungen angebracht. Die tcMEP werden von beiden Seiten des M. tibialis anterior sowie M. gastrocnemius abgenommen. Die SSEPElektroden werden lateral und kaudal am Malleolus medialis fixiert, um den N. tibialis zu stimulieren. Der Stimulus wiederum wird durch Elektroden aufgezeichnet, die auf der Kopfhaut innerhalb der Region des sensorischen Kortex befestigt sind.ErgebnisseDas Anlegen der Elektroden kann leicht erlernt und ohne größere Schwierigkeiten durchgeführt werden. Sind die Elektroden einmal angebracht, erlauben sie eine schnelle Beurteilung und Interpretation der aktuellen Rückenmarksfunktion. Externe Störfaktoren (z.B. unzureichende Impedanz, mangelhafte Elektrodenfixierung, Interferenzen mit medizinisch–technischem Gerät) können schnell identifiziert werden und ermöglichen eine Differenzierung zwischen physiologischen und pathologischen neurologischen Potentialantworten.SchlussfolgerungTcMEP und SSEP ermöglichen eine adäquate, direkte und zuverlässige intraoperative Beurteilung der Rückenmarksfunktion. Gleichzeitig versetzen sie einerseits das Neuromonitoring– Team in die Lage, eine drohende Ischämie zu diagnostizieren und erlauben andererseits dem Chirurg, eine adäquate und rechtzeitige Gegenmaßnahme einzuleiten. Die neurophysiologische Monitoring– Messtechnik stellt für das Operationsteam eine Möglichkeit dar, neurologische Aspekte in den Fokus chirurgischer Eingriffe an der thorakalen und thorakoabdominellen Aorta zu integrieren.SummaryBackgroundThe article exemplifies a procedure concerning the intraoperative neurophysiological placement technique of electrodes to control the spinal cord function during thoracoabdominal aortic aneurysm repair.MethodsIntraoperative monitoring is performed by motor–evoked myogenic potentials after transcranial electric stimulation (tcMEP) and somatosensory–evoked potentials (SSEP). In tcMEP, the stimulating percutaneous needle electrodes are placed at C3 and C4 according to the 10–20 system for EEG–recordings. TcMEP are recorded from the anterior tibial and gastrocnemius muscles on both sides. The SSEP electrodes are located laterally and caudally onto the malleolus medialis in order to stimulate the tibial nerve. The stimulus is documented via electrodes attached to the scalp within the sensory cortex region.ResultsThe application method of the electrodes is both easy to understand and without further difficulties to perform. Once attached, the electrodes provide quick assessment and interpretation of spinal cord function. The identification of external sources of disturbance during the monitoring (e.g. insufficient impedance, unfavorable electrode positioning, and technical interferences caused by medical equipment) enables the supervisor to differentiate between normal and abnormal neurological responses.ConclusionTcMEP and SSEP allow an adequate, direct, and reliable intraoperative assessment of spinal cord function, enabling the surgeon to diagnose an impending ischemia and act accordingly. This measurement technique provides the surgical team with a means for integrating neurological aspects in thoracoabdominal aneurysm repair into the surgical focus.

Pulmonary metastasectomy for thyroid cancer as salvage therapy for radioactive iodine-refractory metastases

OBJECTIVES Distant metastasis arising from thyroid cancer is rare but has been associated with significantly reduced long-term survival, especially when refractory to radioactive iodine ablation. We provide one of the largest studies worldwide reporting the outcome after salvage pulmonary metastasectomy for this entity, aiming to identify prognostic factors and to analyse surgical indication. METHODS We retrospectively analysed the medical records of 43 patients who had undergone pulmonary metastasectomy for radioactive iodine-refractory thyroid cancer from 1985 to 2016. RESULTS The median follow-up period was 77 (95% confidence interval 41-113) months. Twenty-three (53%) patients were alive at the time of analysis. The majority of tumours were follicular thyroid cancer by histology, with 23% identified as Hurthle cell subtype. Five- and 10-year disease-specific (DS) survival was 84% and 59%, respectively. Thirty-one (72%) patients underwent R0-resection with a 5- and 10-year DS survival of 100% and 77%, respectively. This was significantly reduced to 62% and 22% (P = 0.013) in case of incomplete resection, respectively. Ten years after R0-metastasectomy, 17 (55%) patients were recurrence-free. Systematic mediastinal lymphadenectomy was performed in 16 (37%) patients and was associated with improved long-term DS survival (10 years 88% vs 46%, P = 0.034). Moreover, a reduction of > 80% in serum thyroglobulin levels post-metastasectomy correlates with better long-term DS survival (10 years 81% vs 36%, P = 0.007). CONCLUSIONS Pulmonary metastasectomy is associated with good survival for selected patients with radioactive iodine-refractory metastases of differentiated thyroid cancer, especially if R0-resection can be achieved. Moreover, it is worth considering whether a significant reduction of tumour load, as indicated by thyroglobulin serum levels, seems possible.