Current State of the Surgical Treatment of Atrial Fibrillation

Surgery of atrial fibrillation (AF) was first described in 1991 by James Cox in what was named the Cox-Maze procedure, and over the years it has been considered the gold-standard treatment, with best results in maintaining sinus rhythm in the long term. Nevertheless, the complexity and aggressivity of the first techniques of cut-and-sew limited the application of this procedure, and few centers were dedicated to AF surgery. In the past years, however, new devices able to ablate atrial tissue with cryotherapy, radiofrequency, or ultrasounds have facilitated this operation. In the mid-term, other energy devices with laser or microwave have been abandoned due to a lack of consistency in getting transmural lesions in a consistent and reproducible manner. Additionally, better knowledge of the physiopathology of AF, with the importance of triggering zones around the pulmonary veins, has started new minimally invasive techniques to approach paroxysmal and persistent AF patients through thoracoscopy

Less invasive aortic valve surgery: rationale and technique

The unquestionable aims for a less invasive operations are less morbidity, less discomfort, and a reduced hospital stay through an operation which proves equally durable to the conventional approach. Such an operation must be carried out without further risk to the patient or increased difficulty for the surgeon. Whilst most definitions of less invasive coronary surgery include the phrase without cardiopulmonary bypass, this is clearly not yet possible in valve surgery. In valve surgery, the definition of less invasive relates only to the size of incision and rate of recovery. As a result of the discussions during the Heart Lab International Workshop on video-assisted heart surgery in Zürich, October 22-25, 1998, the following conclusions emerged. The partial upper sternotomy with J- or L- shaped extension to the right is the preferred approach for minimally invasive aortic valve surgery. Other methods which sacrify the internal thoracic arteries, open pleural cavities or predispose to long hernia are less satisfactory. A detailed description of the technique proposed is given and its indications and contraindications are discusse

Cadaver donation: structural integrity of pulmonary homografts harvested 48 h post mortem in the juvenile ovine model

Published ArticleAbstract Cryopreserved pulmonary homograft (CPH) implantation remains the gold standard for reconstruction of the right ventricular outflow tract (RVOT). Harvesting homografts\24-h post mortem is the international norm, thereby largely excluding cadaveric donors. This study examines the structural integrity and stability of ovine pulmonary homografts harvested after a 48-h post mortem period, cryopreserved and then implanted for up to 180 days. Fifteen ovine pulmonary homografts were harvested 48-h post mortem and cryopreserved. Five CPH served as a control group (group 1; n = 5). CPH were implanted in the RVOT of juvenile sheep and explanted after 14 days (group 2; n = 5) and 180 days (group 3; n = 5). Leaflet integrity was evaluated by strength analysis, using tensile strength (TS), Young’s modulus (YM) and thermal denaturation temperature (Td), and morphology, including haematoxylin and eosin (H&E), Picrosirius red staining, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and von Kossa stains. Echocardiography confirmed normal function in all implants. In explants, no reduction in TS, YM or Td could be demonstrated and H&E showed mostly acellular leaflet tissue with no difference on Picrosirius red. TEM demonstrated consistent collagen disruption after cryopreservation in all three groups, with no morphological deterioration during the study period. von Kossa stains showed mild calcification in group 3. No deterioration of structural integrity could be demonstrated using strength or morphological evaluations between the controls and implant groups over the study period. Extending the post mortem harvesting time of homografts beyond 24 h did not appear to negatively affect the long-term performance of such transplanted valves in this study

Historical Overview of Vascular Allograft Transplantation

There is a mix of therapeutic options for revascularisation in vascular surgery. The authors performed a literature review on the evolution of vascular allograft transplantation and its use and acceptance by vascular surgeons. This review exposed three stages: the first stage involved preliminary experimentation; the second stage was a decline in use due to long-term complications, and the third stage is its current use in special indications subject to a thorough analysis. There are few indications for the use of vascular allografts in clinical guidelines. However, there are publications of long series of case studies with variable results reflecting international use of the procedure. There is a current trend that favours its use with limited and individualised indications

Pulmonary Thrombosis or Embolism in a Large Cohort of Hospitalized Patients With Covid-19

Objective: We set out to analyze the incidence and predictive factors of pulmonary embolism (PE) in hospitalized patients with Covid-19. Methods: We prospectively collected data from all consecutive patients with laboratory-confirmed Covid-19 admitted to the Hospital de la Santa Creu i Sant Pau, a university hospital in Barcelona, between March 9 and April 15, 2020. Patients with suspected PE, according to standardized guidelines, underwent CT pulmonary angiography (CTPA). Results: A total of 1,275 patients with Covid-19 were admitted to hospital. CTPA was performed on 76 inpatients, and a diagnosis of PE was made in 32 (2.6% [95%CI 1.7-3.5%]). Patients with PE were older, and they exhibited lower PaO:FiO ratios and higher levels of D-dimer and C-reactive protein (CRP). They more often required admission to ICU and mechanical ventilation, and they often had longer hospital stays, although in-hospital mortality was no greater than in patients without PE. High CRP and D-dimer levels at admission (≥150 mg/L and ≥1,000 ng/ml, respectively) and a peak D-dimer ≥6,000 ng/ml during hospital stay were independent factors associated with PE. Prophylactic low molecular weight heparin did not appear to prevent PE. Increased CRP levels correlated with increased D-dimer levels and both correlated with a lower PaO:FiO. Conclusions: The 2.6% incidence of PE in Covid-19 hospitalized patients is clearly high. Higher doses of thromboprophylaxis may be required to prevent PE, particularly in patients at increased risk, such as those with high levels of CRP and D-dimer at admission. These findings should be validated in future studies

Recomendações sobre revascularização do miocárdio

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Quantum and classical confinement of resonant states in a trilayer graphene Fabry-Pérot interferometer

The advent of few-layer graphene has given rise to a new family of two-dimensional systems with emergent electronic properties governed by relativistic quantum mechanics. The multiple carbon sublattices endow the electronic wavefunctions with pseudospin, a lattice analogue of the relativistic electron spin, whereas the multilayer structure leads to electric-field-effect tunable electronic bands. Here we use these properties to realize giant conductance oscillations in ballistic trilayer graphene Fabry-Pérot interferometers, which result from phase coherent transport through resonant bound states beneath an electrostatic barrier. We confine these states by selectively decoupling them from the leads, resulting in transport via non-resonant states and suppression of the giant oscillations. The confinement is achieved both classically, by manipulating quasiparticle momenta with a magnetic field, and quantum mechanically, by locally varying the pseudospin character of the carrier wavefunctions. Our results illustrate the unique potential of trilayer graphene as a versatile platform for electron optics and pseudospintronics.United States. Office of Naval Research (GATE MURI)National Science Foundation (U.S.) (Career Award DMR-0845287)Conselho Nacional de Pesquisas (Brazil

Quantum and classical confinement of resonant states in a trilayer graphene Fabry-Pérot interferometer

The advent of few-layer graphene has given rise to a new family of two-dimensional systems with emergent electronic properties governed by relativistic quantum mechanics. The multiple carbon sublattices endow the electronic wavefunctions with pseudospin, a lattice analogue of the relativistic electron spin, whereas the multilayer structure leads to electric-field-effect tunable electronic bands. Here we use these properties to realize giant conductance oscillations in ballistic trilayer graphene Fabry-Pérot interferometers, which result from phase coherent transport through resonant bound states beneath an electrostatic barrier. We confine these states by selectively decoupling them from the leads, resulting in transport via non-resonant states and suppression of the giant oscillations. The confinement is achieved both classically, by manipulating quasiparticle momenta with a magnetic field, and quantum mechanically, by locally varying the pseudospin character of the carrier wavefunctions. Our results illustrate the unique potential of trilayer graphene as a versatile platform for electron optics and pseudospintronics.United States. Office of Naval Research (GATE MURI)National Science Foundation (U.S.) (Career Award DMR-0845287)Conselho Nacional de Pesquisas (Brazil

Global unmet needs in cardiac surgery

More than 6 billion people live outside industrialized countries and have insufficient access to cardiac surgery. Given the recently confirmed high prevailing mortality for rheumatic heart disease in many of these countries together with increasing numbers of patients needing interventions for lifestyle diseases due to an accelerating epidemiological transition, a significant need for cardiac surgery could be assumed. Yet, need estimates were largely based on extrapolated screening studies while true service levels remained unknown. A multi-author effort representing 16 high-, middle-, and low-income countries was undertaken to narrow the need assessment for cardiac surgery including rheumatic and lifestyle cardiac diseases as well as congenital heart disease on the basis of existing data deduction. Actual levels of cardiac surgery were determined in each of these countries on the basis of questionnaires, national databases, or annual reports of national societies. Need estimates range from 200 operations per million in low-income countries that are nonendemic for rheumatic heart disease to >1,000 operations per million in high-income countries representing the end of the epidemiological transition. Actually provided levels of cardiac surgery range from 0.5 per million in the assessed low- and lower-middle income countries (average 107 ± 113 per million; representing a population of 1.6 billion) to 500 in the upper-middle-income countries (average 270 ± 163 per million representing a population of 1.9 billion). By combining need estimates with the assessment of de facto provided levels of cardiac surgery, it emerged that a significant degree of underdelivery of often lifesaving open heart surgery does not only prevail in low-income countries but is also disturbingly high in middle-income countries