Maximilian Kreibich

Aneurysms of the Pulmonary Artery

Pulmonary artery (PA) aneurysms (PAAs) are rare and infrequently diagnosed. Deterling and Clagett1 discovered 8 cases of PAAs in 109 571 consecutive postmortem examinations. PAAs generally occurred in a younger age group than aortic aneurysms with an equal sex incidence.2 Eighty-nine percent of all PAAs were located in the main PA, whereas only 11% were located in the pulmonary branches.3 When affecting the PA branches, PAAs in the left PA were more common than in the right PA.1 An aneurysm is defined as a focal dilatation of a blood vessel involving all 3 layers of the vessel wall. Pseudoaneurysms, on the other hand, do not involve all layers of the arterial wall but possess a higher risk of rupture. In computed tomography, the upper limit for adults of the main PA diameter is 29 mm, and the upper limit of the interlobar PA is 17 mm.4 Therefore, Nguyen et al5 describe a PAA as a focal dilatation of the PA beyond its maximal normal caliber. In contrast, Brown and Plotnick6 define a PAA as a PA with a diameter exceeding 40 mm, distinguishing between an ectasia of the PA and a true PAA. However, both definitions do not relate the PAA threshold to body dimensions or to the diameters of other vessels. In our center, the upper limit of the main PA diameter (29 mm) was defined as a PAA. In case of a PAA in children, the PAA size was compared with the normal values according to the method of Kampmann et al.7 In high-risk patients, the diameter of the PAA was indexed to the body weight according to patients presenting with an aneurysm of the aorta. Various origins of PAA have been described, allowing us to differentiate among congenital causes, …

Technical details making aortic arch replacement a safe procedure using the Thoraflex™ Hybrid prosthesis

Summary The development of new devices to improve treatment and to explore new indications that have not yet been adequately addressed is a natural consequence of the clinical demand for solutions to as yet unmet needs. The frozen elephant trunk technique was one of the major steps within the last 15 years to improve on existing treatments as well as to explore new indications. The goal of this article is to provide technical details about advances in implantation techniques for the treatment of acute and chronic thoracic aortic pathological conditions.

The frozen elephant trunk technique for the treatment of acute complicated Type B aortic dissection

OBJECTIVES Our goal was to report our preliminary results in patients with acute complicated Type B aortic dissection without a suitable landing zone for primary thoracic endovascular aortic repair who were treated with the frozen elephant trunk (FET) technique. METHODS Within a 25-month period, 14 patients with acute complicated Type B aortic dissection underwent surgical repair using the FET technique. The reasons to perform the FET procedure were an ectatic ascending aorta/arch in 6 patients and the lack of an adequate landing zone in 8 patients. RESULTS No deaths were observed. A non-disabling stroke occurred in 2 patients. Symptomatic spinal cord injury was not observed. The closure of the primary entry tear was successfully achieved in all patients. In 3 patients, a secondary distal thoracic endovascular aortic repair extension was performed during the same hospital stay. The median follow-up period was 6 ± 5 months. CONCLUSIONS The FET technique is an attractive method for the repair of acute complicated Type B aortic dissection without a suitable landing zone for primary thoracic endovascular aortic repair. It should be considered as an alternative in patients who are at high risk for retrograde Type A aortic dissection, in patients with an unfavourable anatomy or in patients with connective tissue disease.

The nitric oxide donor, S-nitroso human serum albumin, as an adjunct to HTK-N cardioplegia improves protection during cardioplegic arrest after myocardial infarction in rats

OBJECTIVES Currently available cardioplegic solutions provide excellent protection in patients with normal surgical risk; in high-risk patients, however, such as in emergency coronary artery bypass surgery, there is still room for improvement. As most of the cardioplegic solutions primarily protect myocytes, the addition of substances for protection of the endothelium might improve their protective potential. The nitric oxide donor, S-nitroso human serum albumin (S-NO-HSA), which has been shown to prevent endothelial nitric oxide synthase uncoupling, was added to the newly developed histidine-tryptophan-ketoglutarat (HTK-N) cardioplegia in an isolated heart perfusion system after subjecting rats to acute myocardial infarction (MI) and reperfusion. METHODS In male Sprague-Dawley rats, acute MI was induced by ligation for 1 h of the anterior descending coronary artery. After 2 h of in vivo reperfusion hearts were evaluated on an isolated erythrocyte-perfused working heart model. Cold ischaemia (4°C) for 60 min was followed by 45 min of reperfusion. Cardiac arrest was induced either with HTK (n = 10), HTK-N (n = 10) or HTK-N + S-NO-HSA (n = 10). In one group (HTK-N + S-NO-HSA plus in vivo S-NO-HSA; n = 9) an additional in vivo infusion of S-NO-HSA was performed. RESULTS Post-ischaemic recovery of cardiac output (HTK: 77 ± 4%, HTK-N: 86 ± 7%, HTK-N + S-NO-HSA: 101 ± 5%, in vivo S-NO-HSA: 93 ± 8%), external heart work (HTK: 79 ± 5%, HTK-N: 83 ± 3%, HTK-N + S-NO-HSA: 101 ± 8%, in vivo S-NO-HSA: 109 ± 13%), coronary flow (HTK: 77 ± 4%, HTK-N: 94 ± 6%, HTK-N + S-NO-HSA: 118 ± 15%, in vivo S-NO-HSA: 113 ± 3.17%) [HTK-N + S-NO-HSA vs HTK P < 0.001; HTK-N + S-NO-HSA vs HTK-N P < 0.05] and left atrial diastolic pressure (HTK: 122 ± 31%, HTK-N: 159 ± 43%, HTK-N + S-NO-HSA: 88 ± 30, in vivo S-NO-HSA: 62 ± 10%) [HTK-N + S-NO-HSA vs HTK P < 0.05; in vivo S-NO-HSA vs HTK-N P < 0.05] were significantly improved in both S-NO-HSA-treated groups compared with HTK and HTK-N, respectively. This was accompanied by better preservation of high-energy phosphates (adenosine triphosphate; energy charge) and ultrastructural integrity on transmission electron microscopy. However, no additional benefit of in vivo S-NO-HSA infusion was observed. CONCLUSIONS Addition of the NO donor, S-NO-HSA refines the concept of HTK-N cardioplegia in improving post-ischaemic myocardial perfusion. HTK-N with S-NO-HSA is a possible therapeutic option for patients who have to be operated on for acute MI.

Anatomic feasibility of an endovascular valve–carrying conduit for the treatment of type A aortic dissection

Objective: The study objective was to screen patients with acute type A aortic dissection for anatomic feasibility of ascending aortic endovascular treatment with a valve‐carrying conduit. Methods: High‐quality computed tomography scans of 167 patients were available for screening. Aortic dimensions were measured using multiplanar reconstruction in the plane perpendicular to the manually corrected aortic center line. The simulated stent‐graft 10‐mm–long landing zones were measured starting at the sinotubular junction (proximal landing zone) and ending at the brachiocephalic trunk (distal landing zone). Exclusion criterion was an entry within the aortic root or the landing zone. Results: In 113 patients (68%), the entry was in a coverable zone in the ascending aorta with sufficient proximal and distal landing zone or in more distal aortic segments. In these patients, the median distance between the proximal and distal landing zone was 89.1 (first quartile: 80.0 mm; third quartile: 101.2 mm) and the median diameter difference was 5.0 mm (2.0; 10.1) (12.3 [4.9; 23.0] %). The diameter difference was less than 2 mm in 32 patients (28%), between 6 mm and 10 mm in 20 patients (18%), between 10 mm and 14 mm in 11 patients (10%), and 14 mm or greater in 10 patients (9%). Conclusions: Two thirds of all patients who present with type A dissections are potential candidates for treatment with endovascular valve–carrying conduits, but most patients would require tapered stent‐grafts. Graphical abstract Figure. No caption available.

Pimobendan in Chronic Right Heart Failure in a Left Ventricular Assist Device Patient

We report the case of a 76-year-old patient who developed chronic right heart failure 1 year after left ventricular assist device implantation due to ischemic cardiomyopathy. Initial recompensation was achieved through dobutamin, sildenafil, and levosimendan treatment. Yet, discharge was successful only after the off-label use of the oral calcium sensitizer pimobendan. Ten months after discharge, the patient presents with no clinical signs of right heart failure and significantly improved right heart function without any impairment in quality of life.

The endovascular repair of the aortic arch using a double branched prosthesis

The last decade has substantially broadened treatment options for patients with thoracic aortic pathology involving the aortic arch. Traditionally, treatment of aortic arch pathology was a domain of open cardiac surgery. The advent of combined vascular and endovascular procedures opened a new field thereby enabling treatment in previously operated and in less fit patients. As a subsequent technological leap, branched arch endografts became available and are currently gaining acceptance in the community. However, current suitability is limited to specific anatomical conditions. When these are respected, early results are very encouraging. Nevertheless, long-term results have to be awaited.

Endovascular treatment of acute Type A aortic dissection—the Endo Bentall approach

Outcome after classical surgical repair of acute Type A aortic dissection has steadily improved over the years and several modifications in cannulation and perfusion added to this achievement. However, subgroups remain where results of classical surgical repair still have room for improvement, particularly patients with severe preoperative malperfusion as well as elderly patients with a limited physiological reserve. So far, only small case series or case reports have been published on the endovascular treatment of dissected ascending aortas. However, a tube alone is not sufficient to fix the entire complex underlying problem in the vast majority of patients with acute Type A aortic dissection. In addition, these published reports are either due to a favorable anatomy or due to very localized disease processes, which are the exception and not the rule. The concept of an endovascular valve-carrying conduit may significantly increase the number of patients suitable for endovascular therapy and it may soon be common practice.

Spontaneous leakage of the Thoraflex™ frozen elephant trunk prosthesis

We report 2 cases of spontaneous, unexpected leakage of the stent graft portion of the Thoraflex (Vascutek, Inchinnan, UK) frozen elephant trunk prosthesis that occurred during second stage surgical thoraco-abdominal aortic replacement. When the descending aortas including the distal portion of the frozen elephant trunk grafts were clamped, spontaneous leakage occurred in the proximal, untouched stent graft portion. This brief communication highlights the previously unreported potential risk of spontaneous leakage through the stent graft portion of the frozen elephant trunk prosthesis during a second stage repair of the thoraco-abdominal aorta.

True-lumen and false-lumen diameter changes in the downstream aorta after frozen elephant trunk implantation

OBJECTIVES To evaluate early and mid-term clinical outcomes and to assess the potential of the frozen elephant trunk technique to induce remodelling of downstream aortic segments in acute and chronic thoracic aortic dissections. METHODS Over a 4-year period, 65 patients (48 men, aged 61 ± 12 years) underwent total aortic arch replacement using the frozen elephant trunk technique for acute (n = 31) and chronic (n = 34) thoracic aortic dissections at our institution. We assessed diameter changes at 3 levels: the L1 segment at the stent graft level; the L2 segment at the thoraco-abdominal transition level and the L3 segment at the coeliac trunk level. True-lumen (TL) and false-lumen (FL) diameter changes were assessed at each level. RESULTS Fifty-six percent of patients had already undergone previous aortic or cardiac surgery. In-hospital mortality was 6%. Symptomatic spinal cord injury was not observed in this series. During a mean follow-up of 12 ± 12 months, late death was observed in 6% of patients. Aortic reinterventions in downstream aortic segments were performed in 28% at a mean of 394 ± 385 days. TL expansion and FL shrinkage were measured in all segments and were observed at each level. This effect was the most pronounced at the level of the stent graft in patients with chronic aortic dissection, TL diameter increased from 15 ± 17 mm before surgery to 28 ± 2 mm (P = 0.001) after 2 years, and the FL diameter decreased from 40 ± 11 mm before surgery to 32 ± 17 mm (P = 0.026). CONCLUSIONS The frozen elephant trunk technique is associated with an excellent clinical outcome in a complex cohort of patients, and also effectively induces remodelling in downstream aortic segments in acute and chronic thoracic aortic dissections. The need for secondary interventions in downstream segments, which mainly depends on the extent of the underlying disease process, remains substantial. Further studies are required to assess the long-term outcome of this approach.