Cardiovascular tissue banking activity during SARS-CoV-2 pandemic: evolution of national protocols and Lombardy experience.

The worldwide pandemic outbreak due to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has created unprecedented challenges for public health services. Lombardy, region of the Northern Italy, has been the first area in the Western world whose organs and tissues procurement programs have had to face the virus pandemic emergency. We retrospectively collected and analyzed data about cardiovascular tissues (CT) in 2019 and in 2020. We aimed to describe the rapid evolution of SARS-CoV-2 regulation laws for tissue donor's selection and harvesting from February 2020 until January 2021. As expected the number of CT donors in 2020 was significantly lower than those of 2019 (66 vs. 99, p value 0.02). The total number of CT collected from donors have been 254 in 2019 and 206 in 2020 (p 0.28). Femoral arteries were the most required vascular tissues (55.5% in 2019 and 40% in 2020). Fifty-five and forty-eight pulmonary valves were implanted in 2019 and 2020, respectively. No differences were found for the types of CT requests between the 2 years. The median age of receivers of vascular tissues was 69.6 ± 14.6 years in the 2019 and 63.3 ± 14.9 years in 2020 (p < 0.01). The median age of receivers of pulmonary and aortic valves did not differ between the 2 years (9.32 ± 11.49 vs. 8.36 ± 10.66 and 48.67 ± 27.19 vs. 37.14 ± 31.97 respectively). Despite the dramatically reduction of donors, the number of CT collected has not decreased significantly and so far the CT distribution rate is comparable to those of 2019.

Submillisievert CT angiography for carotid arteries using wide array CT scanner and latest iterative reconstruction algorithm in comparison with previous generations technologies: Feasibility and diagnostic accuracy.

OBJECTIVES: To assess evaluability and diagnostic accuracy of a low dose CT angiography (CTA) protocol for carotid arteries using latest Iterative Reconstruction (IR) algorithm in comparison with standard 100 kVp protocol using previous generation CT and IR. MATERIALS AND METHODS: 105 patients, referred for CTA of the carotid arteries were prospectively enrolled in our study and underwent CTA with 80 kVp and latest IR algorithm (group 1). Data were retrospectively compared with 100 consecutive patients with similar examination indications that had previously undergone CTA of carotid arteries with a standard 100 kVp protocol and a first generation IR algorithm (group 2). Image quality was evaluated with a 4-point Likert-scale. For each exam CT number, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) at level of common carotid artery (CCA), internal carotid artery (ICA) and at level of Circle of Willis and Effective Dose (ED) were evaluated. 62 Group 1 patients underwent a clinically indicated DSA and results were compared with CTA. RESULTS: No exams reported as not diagnostic. The overall mean CT number value of all arterial segments was above 450 HU in both groups. Significant lower noise, and higher SNR and CNR values were found in group 1 in comparison with group 2 despite the use of 80 kVp. In 62-group 1 patients studied by DSA, CTA showed in a segment-based analysis a sensitivity, negative predictive value and accuracy of 100%, 100% and 99% respectively. Mean ED in group 1 was 0.54 ±â€¯0.1 mSv with a dose reduction up to 86%. CONCLUSIONS: CTA for carotid arteries using latest IR algorithm allows to perform exams with submillisievert radiation exposure maintaining good image quality, overall evaluability and diagnostic accuracy.

Residual antibiotics in decontaminated human cardiovascular tissues intended for transplantation and risk of falsely negative microbiological analyses.

We investigated the presence of antibiotics in cryopreserved cardiovascular tissues and cryopreservation media, after tissue decontamination with antibiotic cocktails, and the impact of antibiotic residues on standard tissue bank microbiological analyses. Sixteen cardiovascular tissues were decontaminated with bank-prepared cocktails and cryopreserved by two different tissue banks according to their standard operating procedures. Before and after decontamination, samples underwent microbiological analysis by standard tissue bank methods. Cryopreserved samples were tested again with and without the removal of antibiotic residues using a RESEP tube, after thawing. Presence of antibiotics in tissue homogenates and processing liquids was determined by a modified agar diffusion test. All cryopreserved tissue homogenates and cryopreservation media induced important inhibition zones on both Staphylococcus aureus- and Pseudomonas aeruginosa-seeded plates, immediately after thawing and at the end of the sterility test. The RESEP tube treatment markedly reduced or totally eliminated the antimicrobial activity of tested tissues and media. Based on standard tissue bank analysis, 50% of tissues were found positive for bacteria and/or fungi, before decontamination and 2 out of 16 tested samples (13%) still contained microorganisms after decontamination. After thawing, none of the 16 cryopreserved samples resulted positive with direct inoculum method. When the same samples were tested after removal of antibiotic residues, 8 out of 16 (50%) were contaminated. Antibiotic residues present in tissue allografts and processing liquids after decontamination may mask microbial contamination during microbiological analysis performed with standard tissue bank methods, thus resulting in false negatives.

Aortic valve leaflet glycosaminoglycans composition and modification in severe chronic valve regurgitation.

BACKGROUND AND AIM OF THE STUDY: The surgical segments of aortic valve leaflets from patients with severe chronic aortic regurgitation were analyzed (by percentage and structure) for their content of complex polysaccharides and glycosaminoglycans (GAGs), and compared with control segments. METHODS: The GAG, hyaluronic acid (HA), chondroitin sulfate (CS) and dermatan sulfate (DS) and disaccharide contents were determined in segments (leaflet, root attachment region and belly) of aortic valve leaflets (non-coronary, left coronary and right coronary) using a multi-analytical approach. RESULTS: The aortic valve leaflets showed the presence of HA and CS/DS, with an overall charge density of -0.51-0.55. The CS/DS polymers showed a 4-sulfated/6-sulfated ratio of -0.70-0.77 in the belly, and -1.60-1.72 in commissure parts (-/+124%). The total amount of GAGs was -1.60-2.40 microg/mg of tissue. A significant increase in sulfated GAGs was observed in all valve parts in patients suffering from severe aortic insufficiency, as well as an increase in the 4-sulfated/6-sulfated ratio in the leaflet belly (-/+102%). CONCLUSION: It is speculated that differences in 4-sulfated/6-sulfated ratio determined in the belly and leaflet attachment region-commissure parts of the leaflets may correlate with the tensile or compressive loading of normal aortic valve regions. At the same time, it may be assumed that the increase in sulfated GAGs and 4-sulfated/6-sulfated ratio in the leaflet belly of valves taken from patients suffering severe aortic insufficiency was consistent with an altered matrix microstructure capable of influencing the hydration of these pathological tissues, and of conditioning their mechanical weakness.

Establishing a procedure for dimethyl sulfoxide removal from cardiovascular allografts: a quantitative study.

The success of allotransplants is critically dependent on both tissue viability and efficient removal of potentially toxic cryopreservants. In this study we analysed the dimethyl sulphoxide (Me2SO) content of cardiovascular tissue samples stored in tissue banks and optimized a washing protocol to be used before surgical implant. We compared the Me2SO content of heart valves, arteries and veins and quantitatively determined by HPLC the washing kinetics of each group of tissue samples under strictly controlled conditions using an industrial washing medium (BASE). Our results showed that heart valves and arteries have significantly slower Me2SO release kinetics than veins. Approximately 20 % of the initial content of cryopreservant could still be detected in the valves and arterial tissue after 15 min of continuous washing. Conversely, veins were almost completely cleared of the cryoprotectant under the same conditions. We propose a washing protocol consisting of two sequential washing with BASE for a total of 25 min for valves and arteries and 15 min for veins. In our hands, this protocol reliably ensures the removal of more than 95 % of the initial Me2SO content.

Heart valve engineering: decellularized aortic homograft seeded with human cardiac stromal cells.

BACKGROUND AND AIM OF THE STUDY: The adult human heart contains a cardiac mesenchymal stromal cell (CStC) population with residual cardiovascular plasticity. The study aim was to investigate the ability of CStCs to populate decellularized aortic homograft leaflets, without mechanical stimulation. METHODS: The ability of CStCs to acquire valve endothelial and interstitial cell phenotypes was tested using in vitro assays. First, trypsin-decellularized aortic leaflets were seeded with CStCs under static conditions; tissue section analyses were then performed before and after decellularization, and at 10, 20, and 30 days after reseeding. RESULTS: Following in vitro treatment, the CStCs differentiated along the endothelial lineage, as shown by their capacity to uptake acetylated low-density lipoprotein and to secrete the pro-angiogenic factor, vascular endothelial growth factor. After seeding, CStCs were able to adhere to the leaflet surface, rescuing up to the 90% of the original cell density and expressing the mature endothelial marker, von Willebrandt factor. The CStC supernatants were also positive for matrix metalloprotease-2 (MMP-2), which confirmed the ability of these cells to penetrate within the leaflet structure; this also suggested that CStCs, once engrafted, would contribute to the extracellular matrix turnover. Accordingly, although at a lower efficiency, CStC repopulation was also evident in the inner portions of the leaflet. CONCLUSION: Seeded CStCs were able to reconstitute, without mechanical stimulation, an endothelial-like layer and to partially infiltrate decellularized homograft leaflets. Hence, CStCs appear to be a potentially useful cell type for engineered heart valves.

Cumulative radiation exposure during thoracic endovascular aneurysm repair and subsequent follow-up.

OBJECTIVES: Thoracic endovascular aneurysm repair (TEVAR) is an appealing alternative to the standard surgical approach, but requires rigorous radiological follow-up. The cumulative radiation exposure (RE) of patients undergoing TEVAR-including pre-operative workup, the procedure and subsequent follow-up computed tomography (CT) imaging-has not previously been investigated. METHODS: From August 2003 to February 2011, 48 patients underwent TEVAR at our institution. Mean age was 66 ± 11 years, with 10 patients (21%) aged <60 years. Forty-one (85%) patients were male; 7 (15%) had urgent/emergent operation; 21 (44%) had undergone previous aortic surgery. Mean aortic diameter was 7.3 ± 2.1 cm. Intra-operative screening time and RE were reviewed, and typical institutional thoracic CT scan RE was calculated (17.8 mSv). Life expectancy of an age- and sex-matched population was estimated to assess the cumulative RE from recurrent CT follow-up. RESULTS: The average screening time was 15.7 ± 11.4 min, with an RE of 11.3 ± 9 mSv. Obese patients had significantly higher RE during TEVAR (Pearson's coefficient = 0.388, P = 0.019). The RE dropped from 14.9 ± 9.4 mSv to 8.6 ± 7.9 mSv (P = 0.033) after a hybrid suite was established. Our institutional TEVAR protocol involves one pre-operative thoracoabdominal CT scan and three follow-up thoracic CT scans for the first year, with a yearly evaluation thereafter. The life expectancy of an age- and sex-matched population was 17 years. A patient adhering to our surveillance protocol would be subjected to an overall exposure of 89 mSv at 1 year and 161 mSv at 5 years, with a projected lifetime RE >350 mSv. CONCLUSIONS: A 2-year RE exceeding the threshold of 100 mSv with a life expectancy >15 years can be estimated to lead to a lifetime risk increase in radiation-induced leukaemia and solid-tumour cancer >2.7%. The risks of cumulative RE especially in younger and/or obese patients must be balanced with the expected morbidity and mortality reduction in TEVAR versus traditional open repair, and the anticipated benefits of recurrent radiographic imaging.

Vascular homograft use in a femoropopliteal rare bacterial infection bypass.

We report on a patient with a femoropopliteal bypass infected by Kytococcus sedentarius. Treatment consisted of resection of the infected prosthesis with homograft substitution and antibiotic therapy started postoperatively. At 6 months followup, the patient showed no signs of infection and results of laboratory findings were normal.

Recurrent pericardial effusion after cardiac surgery: the use of colchicine after recalcitrant conventional therapy.

Pericardial effusion represents a common postoperative complication in cardiac surgery. Nonetheless, it can be resistant to conventional therapy leading to prolonged in-hospital stay and worsening of clinical conditions. Recent literature shows that colchicine therapy should be useful in the treatment of recurrent post surgical pericardial effusion. Hereby we report the case of a patient with postsurgical recurrent effusion treated with colchicine, and a review of literature concerning the use of this old drug.

Transcatheter aortic valve replacement: a dog bone-shaped balloon technique.

We report a new technique of the partially and sequentially gonflage of the transcatheter balloon valve, the so called dog bone shaped technique, which allowed us to approach the aortic root by inflating the valve balloon in two different times, stabilizing the heart and deplacing the valve.

Incidental detection of a giant ductus arteriosus aneurysm by low-dose multidetector computed tomography in an asymptomatic adult.

Aneurysm of the ductus arteriosus is a very rare congenital lesion in adults that can be associated with thromboembolism, rupture, and death. Its detection in a silent clinical phase is very important for planning appropriate treatment and avoiding potentially fatal complications. We report a case of a patent ductus arteriosus aneurysm of very large size (65.5 mm) that was incidentally discovered with low-dose (3.2 mSv) multidetector computed tomography in an asymptomatic 67-year-old man. The presence of coronary disease was also ruled out with this non-invasive imaging modality. Further evaluation with echocardiography and selective angiography confirmed the diagnosis. At surgery, the aneurysm was successfully resected via a left posterolateral thoracotomy.

A bioreactor with compliance monitoring for heart valve grafts.

The drawbacks of state-of-the-art heart valve prostheses lead researchers to explore the prospect of using tissue-engineered constructs as possible valve substitutes. It is widely accepted that the mechanical properties of the construct are improved with mechanical stimulation during in vitro growth. We designed a new dynamic bioreactor with the perspective of using decellularized valve homografts as scaffolds in order to produce tissue-engineered valve substitutes. The design guidelines were (a) compatibility with the procedures for the treatment of homografts; (b) delivery of finely controlled pulsatile pressure loads, which induce strain stimuli that may drive cells toward repopulation of and integration with the natural scaffold; and (c) monitoring the construct's biomechanical status through a comprehensive index, i.e., its compliance. The handling needs during the set-up of the homograft and the use of the bioreactor were minimized. The bioreactor and its automated control system underwent tests with a compliant phantom valve. The estimated compliances are in good agreement with the measured ones. Tests were also carried out with porcine aortic samples in order to assess the hydrodynamic and biomechanical reliability. In the future, monitoring the construct's compliance might represent a key factor in controlling the recellularization of the valve homografts, which provides awareness of the construct's biomechanical status by real-time, non-destructive, and non-invasive means.

Simultaneous quantification of 8-iso-prostaglandin-F(2alpha) and 11-dehydro thromboxane B(2) in human urine by liquid chromatography-tandem mass spectrometry.

Both F(2)-isoprostanes (8-iso-PGF(2alpha)), a well-known marker of oxidative stress, and thromboxanes A(2) (TXA(2)) are involved in atherosclerosis through LDL oxidation and platelet activation. Different aspects of the pathology can be described by 8-iso-PGF(2alpha) and TXA(2) so it is important to determine both their concentrations to monitor the disease progression and/or therapy effects. We developed a simple and sensitive method based on liquid chromatography-tandem mass spectrometry, using electrospray ionization in negative-ion mode, for the simultaneous measurement of the concentration of 8-iso-PGF(2alpha) and 11-dehydro thromboxane B(2) (11-DH-TXB(2)), a TXA(2) metabolite. This method was applied to analyze urine samples collected overnight from 15 atherosclerotic patients, with documented carotid artery sclerosis (CAS), and from 20 controls. The detection limit was 0.097pg/microL for 8-iso-PGF(2alpha) and 0.375pg/microL for 11-DH-TXB(2), with a linear range of 0.78-25pg/microL; the inter- and intraday imprecision was <5% for both metabolites. These analytes were higher in CAS (P<0.005 vs controls) and were positively correlated in patients but not in controls, even after adjustment for age and gender (r=0.60; P=0.032). This highly sensitive, precise, and rapid method allows for the simultaneous determination of 8-iso-PGF(2alpha) and 11-DH-TXB(2) in human urine samples in order to evaluate oxidative stress and platelet aggregation.

Aortic dissection complicating intraaortic balloon pumping: percutaneous management of delayed spinal cord ischemia.

Iatrogenic acute type B dissection is a rare complication of intraaortic balloon pumping. Delayed visceral and spinal cord malperfusion can occur for distal progression of the dissection or relative hypotension. Cerebrospinal fluid drainage and percutaneous balloon fenestration provide a safe and effective method for managing ischemic complications.

An occasional diagnosis of myasthenia gravis--a focus on thymus during cardiac surgery: a case report.

BACKGROUND: Myasthenia gravis, an uncommon autoimmune syndrome, is commonly associated with thymus abnormalities. Thymomatous myasthenia gravis is considered to have worst prognosis and thymectomy can reverse symptoms if precociously performed. CASE REPORT: We describe a case of a patient who underwent mitral valve repair and was found to have an occasional thymomatous mass during the surgery. A total thymectomy was performed concomitantly to the mitral valve repair. CONCLUSION: The diagnosis of thymomatous myasthenia gravis was confirmed postoperatively. Following the surgery this patient was strictly monitored and at 1-year follow-up a complete stable remission had been successfully achieved.