Joachim Schöllhorn

3D blood flow characteristics in the carotid artery bifurcation assessed by flow-sensitive 4D MRI at 3T

To determine three‐dimensional (3D) blood flow patterns in the carotid bifurcation, 10 healthy volunteers and nine patients with internal carotid artery (ICA) stenosis ≥50% were examined by flow‐sensitive 4D MRI at 3T. Absolute and mean blood velocities, pulsatility index (PI), and resistance index (RI) were measured in the common carotid arteries (CCAs) by duplex sonography (DS) and compared with flow‐sensitive 4D MRI. Furthermore, 3D MRI blood flow patterns in the carotid bifurcation of volunteers and patients before and after recanalization were graded by two independent readers. Blood flow velocities measured by MRI were 31–39% lower than in DS. However, PI and RI differed by only 13–16%. Rating of 3D flow characteristics in the ICA revealed consistent patterns for filling and helical flow in volunteers. In patients with ICA stenosis, 3D blood flow visualization was successfully employed to detect markedly altered filling and helical flow patterns (forward‐moving spiral flow) in the ICA bulb and to evaluate the effect of revascularization, which restored filling and helical flow. Our results demonstrate the feasibility of flow‐sensitive 4D MRI for the quantification and 3D visualization of physiological and pathological flow patterns in the carotid artery bifurcation. Magn Reson Med 61:65–74, 2009.

Minimal-invasive, video-assisted vein harvesting for cardiac and vascular surgical procedures.

Harvesting of the saphenous vein is a routine procedure in coronary and peripheral vascular surgery. It is usually performed using a continuous long skin incision. Minor complications are reported in up to 24% (hematoma, wound dehiscence, infection, pain) and major problems necessitating surgical interventions (bleeding, abscess) in less than 1%. These complications lead to a prolonged hospital stay. To reduce these complications we have used a new endoscopic, video-assisted technique in 17 patients. Harvesting of the total length of the saphenous vein is possible with only one 2-3 cm long incision proximally the knee joint. We conclude that this technique is safe, may reduce the morbidity of saphenous vein harvesting and is associated with a perfect cosmetic result.

An approach towards molecular imaging of activated platelets allows imaging of symptomatic human carotid plaques in a new model of a tissue flow chamber

The development of magnetic resonance imaging (MRI) contrast agents targeting epitopes in atherosclerosis is of general interest. In particular, early detection of activated platelets as key players in plaque rupture could provide improved triage of patients. However, so far the efficiency of contrast agents targeting human pathologies can only be examined in animal experiments, which do not necessarily reflect human in vivo conditions. We therefore describe application of a contrast agent targeting activated human platelets in an MRI tissue flow chamber, allowing detection and characterization of contrast agent binding. Microparticles of iron oxide (MPIO) were conjugated to an antibody targeting ligand-induced binding sites (LIBS) on the activated platelet glycoprotein IIb/IIIa-receptor or to control antibody, resulting in LIBS-MPIO or control-MPIO contrast agent. Human endarterectomy specimens from patients with acute stroke or transient ischemic attack were imaged ex vivo before and after contrast agent perfusion using a 9.4 T MRI system. Specimens were measured under static (n = 18) or flow conditions (n = 18) in a specially designed flow chamber setup, simulating physiological conditions in a stenosed vessel. A significant MPIO-induced negative contrast was achieved in MRI by LIBS-MPIO in specimens under static and flow conditions (LIBS-MPIO vs control-MPIO: p < 0.01), and the location of LIBS-MPIO binding corresponded well between histology and MRI (p < 0.05). The number of MPIOs per platelet area on endarterectomy specimens in histology was significantly higher with LIBS-MPIO (p < 0.001). Furthermore, the intensity of contrast agent binding and signal change showed the potential to reflect the severity of clinical symptoms. LIBS-MPIO allows the detection of activated platelets on the surface of symptomatic atherosclerotic human plaques using molecular MRI. Furthermore, the MRI tissue flow chamber setup described could help to evaluate binding properties of contrast agents, and might therefore be an interesting tool for contrast agent development from animal experiments towards clinical application.

Aortic Valve Annuloplasty: New Single Suture Technique

Reconstruction strategies for aortic valve insufficiency in the presence of aortic annulus dilatation are usually surgically challenging. We demonstrate a simple, modified Taylor technique of downsizing and stabilization of the aortic annulus using a single internal base suture. Since April 2011, 22 consecutive patients have undergone safe aortic valve annuloplasty. No reoperations for aortic valve insufficiency and no deaths occurred.

Bypass-Perforation durch Stentimplantation: Komplikationsmanagement. Ein Fallbericht

We describe a case-report on an perforation of an aorto-coronary venous bypass-graft, a complication induced by a stent implantation. Perforations of coronary arteries are rare, however, for interventional cardiologists well-known complications. This case report is of special interest (1) because the perforation did not occur in a coronary artery but rather in an eight year old venous bypass graft and (2) because the perforation was induced by a stent-implantation. In addition, this case-report describes in great detail the management of vessel perforation: several invasive methods contributed to minimize pericardial effusion and to stabilize the patient until surgical revision could be performed. Bei einem 70jährigen Patienten mit koronarer Dreigefäßerkrankung und Zustand nach ACB-Operation 1989 zeigte die diagnostische Kerzkatheteruntersuchung eine filiforme Ostiumstenose des Lambda-Bypasses (R. circumflexus und R. marginalis) sowie eine filiforme Stenose des RIVA-Bypasses unmittelbar vor der peripheren Anastomose. Der ACD-Bypass war verschlossen. Während die Stenose des Lambda-Bypasses problemlos mit gutem Primärresultat mit einem Stent versorgt werden kann, kommt es beim Versuch, die filiforme Stenose des RIVA-ACB zu dilatieren bzw. einen Stent zu implantieren, zu der seltenen vital bedrohlichen Bypass-Perforation mit einer sich rasch entwickelnden Herzbeutel-Tamponade. Wegen sofortigem Blutdruckabfall mit schwerster Schmerzsymptomatik wird sofort ein Autoperfusionskatheter im Bereich der Perforationsstelle positioniert, worauf sich die hämodynamische Situation stabilisiert. Ein Abdichten durch mehrfaches Aufblasen und Ablassen des Perfusionsballons war nicht möglich, so daß dieser entfaltet im Gefäß belassen wird. Dennoch kommt es im weiteren Verlauf zu einer Herzbeuteltamponade. Der abgekapselte Perikarderguß wird an atypischer Stelle (intercostal) erfolgreich punktiert. Über einen Perikard-Pigtail-Katheter werden in der nächsten Stunde ca. sieben Liter Blut entnommen und retransfundiert. Da der kardiologisch interventionelle Weg zwar die Situation stabilisiert, das Problem des Abdichtens der Perforationsstelle jedoch nicht lösen kann, fällt die Entscheidung zur Operation. Mittels linksthorakaler Thoraktomie werden sämtliche Blutkoagel ausgeräumt, trotz sorgfältigster Inspektion kann jedoch keine Blutungsquelle ausfindig gemacht werden. Somit muß von einem Spontanverschluß der Perforationsstelle durch Thrombusbildung ausgegangen werden. Eine Kontrollangiographie eine Woche später zeigte ein gutes Resultat sowohl am Lambda-Bypass als auch am Venen-Bypass auf den RIVA ohne Extravasat oder Nachweis der ehemaligen Perforationsstelle. Der Patient konnte in beschwerdefreiem Zustand nach Hause entlassen werden.

DIE METHODE DER MINIMALINVASIVEN, ENDOSKOPISCHEN, VIDEOASSISTIERTEN VENENENTNAHME

Despite all efforts to find alternative bypass material, there is still a need for arterial grafts for autologous saphenous vein grafts in coronary or peripheral bypass surgery. Harvesting of the saphenous vein is usually performed with a continuous or with interrupted skin incisions. Severe wound complications occur in 1–3% while minor complications occur frequently in up to 43%. We developed an endoscopic harvesting technique using a single 2–3 cm skin incision. Endoscopic vein harvesting was performed in 218 patients undergoing coronary bypass surgery. Severe wound complications did not occur. One hematoma and three seroma were noted. According to our experience, we employ the endoscopic harvesting as a routine procedure especially in patients with a higher risk of wound complications. Trotz aller Bemühungen, ein alternatives Bypassmaterial zu finden, bleibt die autologe Vene das geeignetste Material, von arteriellen Grafts abgesehen, für die koronare und periphere Bypasschirurgie. Sie wird im allgemeinen durch eine kontinuierliche Hautinzision im Subkutangewebe freipräpariert. Zu schwereren Wundheilungsstörungen kommt es in 1–3% der Fälle, leichtere Wundheilungsstörungen kommen mit bis zu 43% wesentlich häufiger vor. Wir entwickelten ein Entnahmeverfahren, durch das die Vena saphena magna durch nur einen 2–3 cm langen Schnitt mittels einer endoskopischen Technik entnommen werden kann. Bei 218 Patienten, die sich einer Bypassoperation unterzogen, entnahmen wir die Vena saphena magna endoskopisch. Schwere Wundheilungsstörungen kamen nicht vor. Ein nicht revisionspflichtiges Hämatom und drei Serome traten postoperativ auf. Aufgrund unserer Erfahrungen benutzen wir die endoskopische Venenentnahme als Routineverfahren bevorzugt bei Patienten, die ein erhöhtes Risiko für Wundheilungsstörungen haben.

Myxoma-Syndrom : eine benigne Erkrankung mit malignem Krankheitsverlauf

Zwischen 1986 und 1995 erkrankte eine heute 36jährige Frau wiederholt an Vorhofmyxomen, die zweimal typischerweise im linken und einmal im rechten Vorhof lokalisiert waren. 1986 stellte sich die Patientin erstmalig mit den Zeichen einer zerebralen Ischämie in der neurologischen Kinik vor. Nachdem das erste symptomlose Tumorrezidiv bei einer Routinekontrolle diagnostiziert werden konnte, erlitt sie neun Jahre später im Rahmen des dritten Myxomwachstums eine Lungenembolie. Die zusätzlich positive Familienanamnese für Herztumoren, eine auffällige Hautpigmentierung und ein Schilddrüsenadenom vervollständigten das Krankheitsbild eines “Myxoma-Syndroms”. Im Vergleich zu Patienten mit einer “sporadischen Myxomerkrankung” sind die Patienten mit “Myxoma-Syndrom” jünger (mittleres Alter 56 vs 25 Jahre), haben eine Lentiginosis (68%) und haben häufig eine positive Familienanamnese für Herztumoren (25%). Die Myxome weisen atypische Lokalisationen auf (85% Atrium, 15% Ventrikel, je 50% solitär und multilokulär) und haben in den ersten fünf Jabren eine hohe Rezidivrate (18%). Da die klinischen Zeichen kardialer Tumoren häufig sehr unspezifisch sind, bleibt es häufig den bildgebenden Verfahren vorbehalten, die Diagnose eines Herztumors zu stellen. Hierbei spielt die transösophageale Echokardiographie eine besondere Rolle, die in diesem Fallbericht hervorgehoben wird. We are reporting on a 36 year-old woman who presented with recurrent cardiac myxomas over a period of nine years. Two of the tumors typically originated in the left atrium and one in the right atrium. Tumor embolization was the presenting symptom twice, leading to reversible cerebral ischemia and minor pulmonary embolism, respectively. The third tumor remained asymptomatic and was detected during routine echocardiographic examination. Based on a positive family history of cardiac tumors, a facially pronounced hyperpigmentation of the skin and the presence of a thyroid adenoma, the diagnosis of a “myxoma syndrome” was established. Patients with “myxoma syndrome” are generally younger than their counterparts with “sporadic myxoma” (mean age at diagnosis 25 vs. 56 years) and have a high frequency of unusual skin freckling (68%). Familial clustering of cardiac myxomas is also frequent (25%). The tumors may be located in any of the cardiac chambers (87% in the atrias, 13% in the ventricles, 50% at multiple sites simultaneously) and have relatively high (18%) 5-year recurrence rate after surgical excision. Since the clinical signs of cardiac tumors are non-specific, diagnosis essentially relies on cardiac imaging by echocardiography, computer tomography, or angiography. The superiority of transesophageal echocardiography is emphasized in this report.

A retrospective audit of long-term lower limb complications following leg vein harvesting for coronary artery bypass grafting

We would like to congratulate Dr Garland and colleagues for their important and honest paper concerning the incidence of lower limb complications following leg vein harvesting for coronary artery bypass grafting (CABG) [1]. They have described clearly the high incidence of wound infections, numbness, pain and unilateral leg swelling after conventional vein harvesting for CABG. In addition, the authors could not confirm the previously reported association to risk factors by other groups, such as diabetes or peripheral vascular disease. Garland et al. [1] also point to the fact that most of the wound infections occur following hospital discharge and are associated with a high rate of postoperative antibiotic use. The rate of wound infection after vein harvesting is even higher in patients with vascular operations (17–44%) [2]. Even though arterial conduits are increasingly used, at least one vein is still harvested in the majority of CABG procedures worldwide. Given the good shortand long-term results of surgical revascularization for patients with coronary artery disease, problems at the leg vein harvesting site are often the major complaint of the patients after these procedures. Major efforts are being undertaken to reduce the size of the chest incision (half sternotomy, lateral thoracotomy, usage of ports), even though the complication rate from a sternal incision is relatively low. Therefore, every effort should be undertaken to reduce the complications from the conventional vein harvesting procedures, which are described by Garland et al. [1]. With the current availability of the minimally invasive, endoscopic vein harvesting procedure, a solution to this postoperative complication seems to be realistic. The authors have pointed to this technique in their report and have also listed potential drawbacks of this method, such as increased harvest time, additional expense and potential for vein trauma [1]. Our group [3,4] as well as many others have shown the significant advantages of this technique as compared to the conventional procedure in terms of wound infections, neuropathy, pain, swelling as well as patient comfort and satisfaction. We are using this method for 7 years and this has resulted in an almost complete disappearance of any leg wound complications. Currently all veins in all patients are harvested with this method with a very low rate of contraindications. Our group has developed a non-disposable, minimal-invasive, endoscopic harvesting system (Vein harvesting system Freiburg, Storz Co., Tuttlingen, Germany) which needs only one 3–4 cm, horizontal skin incision medially above the knee for harvesting the entire saphenous vein from the ankle to the groin. Harvest time is no longer prolonged as compared to the conventional method and is sometimes even faster. The learning curve is approximately 2 months and this method is now performed by all surgical assistants after their 2nd or 3rd year of training. The costs are reduced to the one-time purchase of the endoscopic system. The vein harvesting system is nondisposable. The potential for endothelial trauma has been addressed by us as well as by others [5]. There has been no report of any additional damage to the vein endothelium as compared to the conventional technique. In summary, minimally-invasive endoscopic vein harvesting is able to reduce significantly the well known and by Garland et al. reported complications of vein harvesting and should be used routinely. Garland and co-workers are to be congratulated for their study and for emphasizing again the importance of this aspect of CABG.