Development of our TAVI protocol for emergency initiation of cardiopulmonary bypass

All transcatheter aortic valve implantation (TAVI) cases are done in our hybrid operating room with a multidisciplinary team and a primed cardiopulmonary bypass (CPB) circuit on pump stand-by. We decided that we would resuscitate all patients undergoing a TAVI procedure via a transfemoral, transapical or transaortic approach, if required. Perfusion plays an essential role in providing rescue CPB for patient salvage when catastrophic complications occur. To coordinate the multidisciplinary effort, we have developed a written safety checklist that assigns a pre-determined role for team members for the rapid sequence initiation of CPB. Although many TAVI patients are not candidates for conventional aortic valve replacements, we feel strongly that rescue CPB should be offered to all TAVI patients to allow the correction of potentially reversible complications. This protocol is included in every surgical "Time Out" involving a TAVI procedure (Figure 1). The protocol has led to rapid and safe CPB initiation in less than five minutes of cardiac arrest. It has also led to a coordinated and consistent team, with pre-specified roles and improved communication. We discuss a case series of four TAVI patients who required emergent use of CPB. The first few cases did not have a written protocol. The experience from these cases led to the development of our protocol. We identified a lack of coordination, wasted movements, unnecessary delayed resuscitation and overall chaos, each of which was targeted for correction with the protocol. We will discuss the merits of the protocol in two recent TAVI cases which required emergent CPB.

Que Fatores Determinam os Níveis de Atividade Física após Programa de Reabilitação Cardíaca?

Introduction: The Cardiac Rehabilitation Programs have gained tremendous importance in the prevention of cardiovascular disease and it’s a challenge to ensure the practice of regular exercise during and after the supervised program. The aim of this study was to determine the factors that influence the physical activity habits at 12 months after the Cardiac Rehabilitation Program.Material and Methods: Prospective study, including 580 patients with ischemic heart disease who were consecutively oriented for Cardiac Rehabilitation Program at Cardiovascular Prevention and Rehabilitation Unit of Centro Hospitalar do Porto, between January 2008 and June 2011. Physical activity levels were measured with International Physical Activity Questionnaire which was calculated at the beginning of the program, 3 and 12 months later. The following variables were chosen and tested as potential determinants of physical activity habits of 12 months after program: age; sex; modifiable risk factors; functional capacity (achieved in treadmill stress test); laboratory analysis (HbA1c, lipid profile, C-Reactive Protein and Brain Natriuretic Peptide). A linear regression analysis was carried to identify the significant determinants and to find the best model adjustment.Results: Advanced age, female gender, functional capacity and low levels of physical activity prior to the Cardiac Rehabilitation Program, as well as a weak evolution of the International Physical Activity Questionnaire during the program were the best univariable predictors of a less favourable evolution of the International Physical Activity Questionnaire during 12 months of follow-up. A multivariable linear regression analysis showed that the best explanatory model included age, gender and evolution of the International Physical Activity Questionnaire during the supervised program (R2 Adj. = 0.318; f = 60.62, p < 0.001).Conclusion: The identification of certain subgroups of patients with lower tendency toward physical activity is beneficial to enable timely and individualized strategies to maximize the therapeutic and preventive potential of the Cardiac Rehabilitation Programs.

Soil microstructure and organic matter: keys for chlordecone sequestration

Past applications of chlordecone, a persistent organochlorine pesticide, have resulted in diffuse pollution of agricultural soils, and these have become sources of contamination of cultivated crops as well as terrestrial and marine ecosystems. Chlordecone is a very stable and recalcitrant molecule, mainly present in the solid phase, and has a strong affinity for organic matter. To prevent consumer and ecosystem exposure, factors that influence chlordecone migration in the environment need to be evaluated. In this study, we measured the impact of incorporating compost on chlordecone sequestration in andosols as a possible way to reduce plant contamination. We first characterized the transfer of chlordecone from soil to plants (radish, cucumber, and lettuce). Two months after incorporation of the compost, soil-plant transfers were reduced by a factor of 1.9-15 depending on the crop. Our results showed that adding compost modified the fractal microstructure of allophane clays thus favoring chlordecone retention in andosols. The complex structure of allophane and the associated low accessibility are important characteristics governing the fate of chlordecone. These results support our proposal for an alternative strategy that is quite the opposite of total soil decontamination: chlordecone sequestration.

[What factors determine the levels of physical activity after cardiac rehabilitation program?]

INTRODUCTION

The Cardiac Rehabilitation Programs have gained tremendous importance in the prevention of cardiovascular disease and it's a challenge to ensure the practice of regular exercise during and after the supervised program. The aim of this study was to determine the factors that influence the physical activity habits at 12 months after the Cardiac Rehabilitation Program.

MATERIAL AND METHODS

Prospective study, including 580 patients with ischemic heart disease who were consecutively oriented for Cardiac Rehabilitation Program at Cardiovascular Prevention and Rehabilitation Unit of Centro Hospitalar do Porto, between January 2008 and June 2011. Physical activity levels were measured with International Physical Activity Questionnaire which was calculated at the beginning of the program, 3 and 12 months later. The following variables were chosen and tested as potential determinants of physical activity habits of 12 months after program: age; sex; modifiable risk factors; functional capacity (achieved in treadmill stress test); laboratory analysis (HbA1c, lipid profile, C-Reactive Protein and Brain Natriuretic Peptide). A linear regression analysis was carried to identify the significant determinants and to find the best model adjustment.

RESULTS

Advanced age, female gender, functional capacity and low levels of physical activity prior to the Cardiac Rehabilitation Program, as well as a weak evolution of the International Physical Activity Questionnaire during the program were the best univariable predictors of a less favourable evolution of the International Physical Activity Questionnaire during 12 months of follow-up. A multivariable linear regression analysis showed that the best explanatory model included age, gender and evolution of the International Physical Activity Questionnaire during the supervised program (R2 Adj. = 0.318; f = 60.62, p < 0.001).

CONCLUSION

The identification of certain subgroups of patients with lower tendency toward physical activity is beneficial to enable timely and individualized strategies to maximize the therapeutic and preventive potential of the Cardiac Rehabilitation Programs.

Exposure to Cr(VI) induces organ dependent MSI in two loci related with photophosphorylation and with glutamine metabolism

Chromium (Cr), as a mutagenic agent in plants, has received less attention than other metal pollutants. To understand if Cr induces microsatellite instability (MSI), Pisum sativum seedlings were exposed for 28 days to different concentrations of Cr(VI) up to 2000mgL(-1), and the genetic instability of ten microsatellites (SSRs) was analyzed. In plants exposed to Cr(VI) up to 1000mg L(-1), MSI was never observed. However, roots exposed to 2000mgL(-1) displayed MSI in two of the loci analyzed, corresponding to a mutation rate of 8.3%. SSR2 (inserted in the locus for plastid photosystem I 24kDa light harvesting protein) and SSR6 (inserted in the locus for P. sativum glutamine synthetase) from Cr(VI)-treated roots presented alleles with, respectively, less 6bp and more 3bp than the corresponding controls. This report demonstrates that: (a) SSRs technique is sensitive to detect Cr-induced mutagenicity in plants, being Cr-induced-MSI dose and organ dependent (roots are more sensitive); (b) two Cr-sensitive loci are related with thylakoid photophosphorylation and with glutamine synthetase, respectively; (c) despite MSI is induced by Cr(VI), it only occurs in plants exposed to concentrations higher than 1000mgL(-1) (values rarely found in real scenarios). Considering these data, we also discuss the known functional changes induced by Cr(VI) in photosynthesis and in glutamine synthetase activity.

Comparison of visual and refractive results of Toric Implantable Collamer Lens with bioptics for myopic astigmatism

PURPOSE

To compare visual and refractive results of Toric Implantable Collamer Lens (TICL) and bioptics (ICL plus excimer corneal surgery) to treat myopic astigmatism.

METHODS

Eighty-one eyes underwent TICL implantation and 83 eyes were treated with bioptics (corneal ablation was performed between 1.5 and 6 months after ICL implantation). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, adverse events, safety, and efficacy were evaluated 12 months postoperatively.

RESULTS

At 12 months postoperatively, the mean spherical equivalent was -0.15 ± 0.36 diopters (D) in the TICL group and -0.08 ± 0.26 D in the bioptics group (p = 0.099). Sixty-six (81.5 %) and 78 (94.0 %) eyes were within ±0.50 D for TICL and bioptics groups, respectively. The mean Snellen UDVA was not statistically different between both procedures (p = 0.909); 53 (65.4 %) and 54 (65.1 %) eyes achieved at least 20/25 or better in TICL and bioptics groups, respectively. No eye had lost more than two lines of CDVA, and 32.1 % of eyes (26/81) in the TICL group and 57.8 % of eyes (48/83) in the bioptics group had better postoperative UDVA than preoperative CDVA (p < 0.001). Safety was not statistically different between groups (p = 0.464) while efficacy was significantly higher in the bioptics group (p = 0.000). Two eyes with a TICL were treated to correct TICL decentration.

CONCLUSIONS

Bioptics showed slightly better outcomes in some clinical measures such as uncorrected visual acuity, efficacy, and refractive predictability. TICL implantation shows reliable results similar to bioptics. A single procedure with TICL implantation might be preferred, eliminating the inherent risks of laser treatments and the risks of a second surgical procedure.

Clinical and biochemical outcomes for additive mesenteric and lower body perfusion during hypothermic circulatory arrest for complex total aortic arch replacement surgery

Surgical repair of transverse aortic arch aneurysms frequently employ hypothermia and antegrade cerebral perfusion as protective strategies during circulatory arrest. However, prolonged mesenteric and lower limb ischemia can lead to significant lactic acidosis and end organ dysfunction, which remains a significant cause of post-operative morbidity and mortality. We report our experience with additive warm mesenteric and lower body perfusion (1-3 L/min, 30°C) in addition to continuous cerebral and myocardial perfusion in 5 patients who underwent total aortic arch replacement with trifurcated head vessel re-implantation and distal elephant trunk reconstruction. Concomitant surgical procedures included re-operations (2), aortic root operations (2), coronary artery bypass (2) and descending thoracic aortic replacement (1). Serum lactate levels demonstrated a rapid decline from a peak 9.9±2.6 post circulatory arrest to 3.4±2.0 in the intensive care unit (ICU). The lowest serum bicarbonate levels were 19.3±3.5 mmol/L, intra-operatively, which normalized to 28.4±2.4 mmol/L on return to the ICU. The lowest pH levels were 7.25±0.10, corrected to 7.43±0.04 on return to the ICU. Mean cardiopulmonary bypass and aortic cross-clamp times were 361±104 and 253±85 minutes, respectively. Mean cerebral and lower body circulatory arrest times were 0 (0) and 50±35 minutes, respectively. The mean time required for systemic rewarming was 95±66 minutes. There were no in-hospital mortalities and no patient experienced any neurological, mesenteric, renal or lower limb ischemic complications. Two patients required mechanical ventilation >24 hours, and one patient returned for reoperation for bleeding. Median intensive care unit and total hospital lengths of stay were 5 and 16 days, respectively. Our results suggest early serum lactate clearance, normalization of acidosis, and metabolic recovery when utilizing a simultaneous cerebral perfusion and warm body protection strategy for complex aortic arch surgery. This additive perfusion strategy may attenuate visceral and lower body ischemia that normally develops during periods of deep hypothermic circulatory arrest.

Long-term evaluation of the central vault after phakic Collamer® lens (ICL) implantation using OCT

PURPOSE

The aim of this work is to evaluate the changes in the central vault after using implantable Collamer® lenses (ICL) to correct myopia.

METHODS

This cohort study included 133 eyes; mean spherical equivalent -9.47 ± 3.71 diopters (D) (range: -2.75 to -22.25 D) who underwent ICL V4 implantation. Besides a complete ophthalmologic examination, the central vaulting was measured with Visante OCT and evaluated between different periods of follow-up (1 week, 1, 3, and 6 months, and yearly postoperatively). Post-operative time ranged from 6 to 73 months.

RESULTS

Within the first 6 months, the mean central vaulting dropped from 510 ± 238 μm (range 100 to 940 μm) to 439 ± 231 μm (range 90 to 910) a significant decrease by 71 ± 58 μm (range -170 to 30 μm) (p = 0.028) with a trend to a lower reduction after this period. After 36 month from ICL implantation, this variation tends to be smaller with the majority of the eyes having a mean decrease smaller than 2 μm per month. Initial vault (Spearman Rho = -0.237, p = 0.006) was the factor more significantly associated with decrease in vault; eyes presenting a reduction in vault >100 μm had an average initial vault that was 141 μm and 184 μm higher than eyes with no change or with increase in vault over time, respectively.

CONCLUSIONS

This study shows a continuous reduction of central vault over time. The reduction is highest during the first 6 months and tends to be lower and slow down over time. The decrease of vaulting was more pronounced in eyes with larger initial vaulting.

Clinical evaluation of the IOPen® in a glaucomatous population

The aim of this study was to evaluate the level of agreement of measurements of intraocular pressure (IOP) taken by a rebound tonometer (IOPen®), in comparison to a reference Goldmann applanation tonometer (GAT) in a glaucomatous population. Both eyes from 60 patients were assessed with the two tonometers, the induction tonometry was performed first by an experienced optometrist, and the GAT by an ophthalmologist. In this study, statistically significant differences were found when comparing the IOPen® tonometer with the GAT tonometer (p < 0.001), mean differences were -4.81 ± 4.31 and -4.76 ± 5.76 mmHg (mean ± S.D.) for the right eye and left eye respectively These values represent an underestimation in the present population by the IOPen® when compared with the GAT. Frequency distribution of differences demonstrated that in more than 71.6% of the measurements the IOP readings differed by more than 3 mmHg between the two tonometers. These results suggest that IOPen® should be used with great caution in the determination of IOP.

Comparison of the IOPen and iCare rebound tonometers with the Goldmann tonometer in a normal population

This study proposes to evaluate the level of accuracy of intraocular pressure (IOP) measurements of a second generation rebound tonometer (IOPen, taking as references the Goldmann Applanation Tonometer (GAT) and the iCare rebound tonometer. The right eyes of 101 consecutive clinical patients were assessed with the three tonometers. The IOPen and iCare measurements were taken by two different optometrists and the GAT by an ophthalmologist. In this study, statistically significant differences were found when comparing the IOPen tonometer with the other two tonometers (p < 0.001). The IOPen underestimated the IOP value when compared to the GAT and the iCare (mean differences were 2.94 +/- 4.65 mmHg and 3.20 +/- 4.72 mmHg (mean +/- S.D.), respectively). The frequency distribution of differences demonstrated that in more than 55% of measurements the IOP readings differed by more than 3 mmHg between the IOPen and the GAT. Based on the present population study, these results suggest that IOPen measurements should be interpreted with caution.

Fast advection of magnetic fields by hot electrons

Experiments where a laser-generated proton beam is used to probe the megagauss strength self-generated magnetic fields from a nanosecond laser interaction with an aluminum target are presented. At intensities of 10(15)   W  cm(-2) and under conditions of significant fast electron production and strong heat fluxes, the electron mean-free-path is long compared with the temperature gradient scale length and hence nonlocal transport is important for the dynamics of the magnetic field in the plasma. The hot electron flux transports self-generated magnetic fields away from the focal region through the Nernst effect [A. Nishiguchi, Phys. Rev. Lett. 53, 262 (1984)] at significantly higher velocities than the fluid velocity. Two-dimensional implicit Vlasov-Fokker-Planck modeling shows that the Nernst effect allows advection and self-generation transports magnetic fields at significantly faster than the ion fluid velocity, v(N)/c(s)≈10.