Aortic Valved Homograft Degeneration: Surgical or Transcatheter Approach for Repeat Aortic Valve Replacement?

OBJECTIVES: Aortic valved allografts (homografts) have been used alternatively to mechanical or biological valve prostheses in expectation of better durability; however, homograft valves do degenerate, and redo procedures have proven challenging due to heavy wall calcification. The aim of the study was to compare the outcome of open surgical (SAVR) and transcatheter aortic valve replacement (TAVR) in degenerated homografts. METHODS: Between 1993 and 2022, 81 patients underwent repeat aortic valve procedures having previously received an aortic homograft. The redo had become necessary due to regurgitation in 85% and stenosis in 15%. Sixty-five percent underwent open surgery, 35% TAVR. RESULTS: Isolated SAVR was possible in 79% and root procedures were necessary in 21%. TAVR was performed in 79% via transfemoral and 21% via transapical access. Median prosthetic valve size was 23 (22.3-23.2) mm in the SAVR and 26 (25.2-26.9) in the TAVR group.30-day mortality was 0% in the TAVR and 7% in the SAVR group (p=n.s.). TAVR showed a significantly better outcome concerning prolonged ventilation (0 vs. 21%, p=0.013) as well as ICU (1 vs. 2 days; p<0.001) and in-hospital stay (10.5 vs. 13 days; p=0.028). 5-year survival was statistically comparable between groups and no severe leakage was observed. CONCLUSIONS: SAVR following structural homograft degeneration shows acceptable results, but the perioperative risk remains substantial and poorly predictable. TAVR presents a reasonable and more easily accessible alternative and is associated with good short- and midterm results. In the absence of relevant contraindications, TAVR is presently the preferred treatment option for these patients at our center.

Case Report: Incidental finding of an atresia of the inferior vena cava-a challenge for cardiac surgery.

Inferior vena cava atresia is a rare and usually asymptomatic condition. However, when these patients undergo cardiac surgery, it can present an unexpected and challenging situation for the surgeon. Specifically, adequate venous drainage during cardiopulmonary bypass (CPB) is a critical issue here and may require an extension of cannulation strategies. Adequate preoperative diagnostics, ideally with imaging modalities such as CT angiography or MRI, are required for optimal surgical planning. Here, we describe a rare case of thoracic ascending aortic aneurysm with concomitant inferior vena cava atresia that was successfully operated on. With adequate preoperative planning, we were able to perform an operation without unforeseen complications with standard initialization of CPB.

Visceral and renal malperfusion syndromes in acute aortic dissection type A: the fate of the branch vessel.

BACKGROUND: Malperfusion in acute aortic dissection is not uncommonly observed and associated with a highly significant increase in mortality and morbidity. Of the various malperfusion syndromes, visceral and renal involvement is the most challenging in terms of correct and timely diagnosis as well as the choice of management strategy. The aim of this study was to identify the pathology and associated fate of each visceral and renal vessel in acute type A dissections. METHODS: Over a 12-year period, 167 consecutive patients with acute dissection type A extending into the thoracoabdominal aorta were included and radiographic images analyzed with a focus on individual branch vessel pathology and dependent organ perfusion. RESULTS: Sixty-five patients (39%) were diagnosed with radiological signs of malperfusion on the CT Images. Of those, 20% expired during the hospital stay, compared to 8% without malperfusion. The left renal artery was the most frequently affected by dissection (31%) or false lumen supply (28%). False lumen perfusion was more often associated with manifest malperfusion than an extension of the dissection flap into the branch vessel. During the study period, there was no preference of surgical procedure treating the malperfusion. CONCLUSIONS: Malperfusion of the visceral/renal branches of a dissected aorta represents a manifest indicator for postoperative mortality and morbidity. Neither clinical outcome, nor the fate of individual vessels can reliably be predicted prior to proximal reconstruction and thus, surgical strategy cannot generally be defined alone by radiological findings.

Bridging patients in cardiogenic shock with a paracorporeal pulsatile biventricular assist device to heart transplantation-a single-centre experience.

OBJECTIVES: We evaluated the outcome of patients in cardiogenic shock receiving a paracorporeal pulsatile biventricular assist device as a bridge to transplantation. METHODS: We performed a retrospective single-centre analysis of all patients who received a Berlin Heart Excor® at our institution between 2004 and 2019. RESULTS: A total of 97 patients (90 adults, 7 paediatric) were analysed. Eighty-four patients were in Interagency Registry for Mechanically Assisted Circulatory Support level 1 (80 adults, 4 paediatric). Diagnoses were dilated cardiomyopathy (n = 41), ischaemic cardiomyopathy (n = 17) or myocardial infarction (n = 4), myocarditis (n = 15), restrictive cardiomyopathy (n = 2), graft failure after heart transplant (n = 7), postcardiotomy heart failure (n = 5), postpartum cardiomyopathy (n = 3), congenital heart disease (n = 1), valvular cardiomyopathy (n = 1) and toxic cardiomyopathy (n = 1). All patients were in biventricular heart failure and had secondary organ dysfunction. The mean duration of support was 63 days (0-487 days). There was a significant decrease in creatinine values after assist device implantation (from 1.83 ± 0.79 to 1.12 ± 0.67 mg/dl, P = 0.001) as well as a decrease in bilirubin values (from 3.94 ± 4.58 to 2.65 ± 3.61 mg/dl, P = 0.084). Cerebral stroke occurred in 16 patients, bleeding in 15 and infection in 13 patients. Forty-eight patients died on support, while 49 patients could be successfully bridged to transplantation. Thirty-day survival and 1-year survival were 70.1% and 41.2%, respectively. CONCLUSIONS: A pulsatile biventricular assist device is a reasonable therapeutic option in cardiogenic shock, when immediate high cardiac output is necessary to rescue the already impaired kidney and liver function of the patient.

Routine Stent Bridging to the Supraaortic Vessels in Aortic Arch Replacement: 10-Year-Experience.

BACKGROUND: The supraaortic vessel anastomosis stent bridging (SAVSTEB) technique simplifies the reattachment of the supraaortic vessels in aortic arch surgery; however, follow-up data are limited. The study aimed to investigate the stent-related performance and complications. METHODS: Between February 2009 and September 2020, 112 patients underwent total arch replacement with a tetrabranched graft and using the SAVSTEB technique. Mean age was 59.3±12.7 years, and male gender prevailed. Nineteen percent of these patients had acute aortic dissection extending into the supraaortic vessels, 12% had chronically dissected vessels, and 70% had unaffected vessels. The left subclavian artery, left common carotid artery, and innominate artery were bridged in 88%, 75%, and 2%, respectively, and an aberrant right subclavian artery was bridged in 2%. RESULTS: Total stent experience was 341 stent-years, and stent patency was found in 98%. Technical success was achieved in all but 1 case. One percent of patients had major stent thrombosis requiring reintervention. Minor stent thrombosis was found in 2%. No endoleak was found, and the number of new-onset dissections distal to the stent was 4%. Freedom from stent-related events was estimated at 89.1% ± 0.5% at 3 years. The stroke rate was 10%, with the highest incidence among nondissected vessels. The vertebral artery was overstented in 15%, and 2% of these cases were associated radiographically with stroke. CONCLUSIONS: SAVSTEB is a comparatively simple, safe, and efficacious technique to create the anastomosis between tetrabranched arch grafts and the supraaortic arteries in the short and intermediate term. Bleeding from the anastomoses, kinking, and scar-associated stenosis are negligible; however, vertebral overstenting remains a critical technical issue.

Time is of the essence: where can we improve care in acute aortic dissection?

OBJECTIVES: In acute aortic dissection type A various components of the diagnostic and logistic pathways may affect the time to definitive treatment. This study aimed to characterize these components and to identify factors delaying the optimal management within our institutional referral network. METHODS: Between January 2017 and January 2020, 96 consecutive patients with classical aortic dissection type A were admitted (28%) or referred (72%) to our tertiary care centre and analysed retrospectively. Data are presented as medians (25th-75th quartile). RESULTS: Median age was 66 years (56-74), 63% were male. Most of the patients were primarily admitted to a cardiology department (40%), whereas about a fourth were admitted to departments for internal medicine (26%) and general surgery (27%). The median interval from the onset of symptoms to hospital admission was 2.1 (1-4.4) h. From admission to confirmed diagnosis it took 2.1 (0.6-9.5) h and the median interval from confirmed diagnosis to admission at our specialized tertiary care aortic centre was 1.5 (0.9-2.4) h. Following admission to our centre, 1.1 (0.5-1.9) h passed until the induction of anaesthesia and 0.8 (0.0-1.1) h until the start of surgery. The total interval from the onset of symptoms to the start of surgery was 7.6 h (5.1-12.3). CONCLUSIONS: The marked variability of the time from symptoms to diagnosis at any medical facility demonstrates the importance of awareness in the optimization of the treatment of acute aortic dissection type A.

Aortic Arch Hybrid Repair: Stent-Bridging of the Supra-Aortic Vessel Anastomoses (SAVSTEB).

The reattachment of the supra-aortic vessels during hybrid arch repair using a branched prosthesis is time consuming and sometimes technically challenging. Here, we describe the surgical technique of bridging the end-to-end anastomoses between the graft branches and the supra-aortic vessels by self-expanding covered stents to reduce suturing time, avoid anastomotic bleeding, enhance true lumen remodeling, and improve vessel alignment to the hybrid graft.

A multi-sensor RSS spatial sensing-based robust stochastic optimization algorithm for enhanced wireless tethering.

The reliability of wireless communication in a network of mobile wireless robot nodes depends on the received radio signal strength (RSS). When the robot nodes are deployed in hostile environments with ionizing radiations (such as in some scientific facilities), there is a possibility that some electronic components may fail randomly (due to radiation effects), which causes problems in wireless connectivity. The objective of this paper is to maximize robot mission capabilities by maximizing the wireless network capacity and to reduce the risk of communication failure. Thus, in this paper, we consider a multi-node wireless tethering structure called the "server-relay-client" framework that uses (multiple) relay nodes in between a server and a client node. We propose a robust stochastic optimization (RSO) algorithm using a multi-sensor-based RSS sampling method at the relay nodes to efficiently improve and balance the RSS between the source and client nodes to improve the network capacity and to provide redundant networking abilities. We use pre-processing techniques, such as exponential moving averaging and spatial averaging filters on the RSS data for smoothing. We apply a receiver spatial diversity concept and employ a position controller on the relay node using a stochastic gradient ascent method for self-positioning the relay node to achieve the RSS balancing task. The effectiveness of the proposed solution is validated by extensive simulations and field experiments in CERN facilities. For the field trials, we used a youBot mobile robot platform as the relay node, and two stand-alone Raspberry Pi computers as the client and server nodes. The algorithm has been proven to be robust to noise in the radio signals and to work effectively even under non-line-of-sight conditions.