Opportunities for shared decision-making about major surgery with high-risk patients: a multi-method qualitative study.

BACKGROUND: Little is known about the opportunities for shared decision-making when older high-risk patients are offered major surgery. This study examines how, when, and why clinicians and patients can share decision-making about major surgery. METHODS: This was a multi-method qualitative study, combining video recordings of preoperative consultations, interviews, and focus groups (33 patients, 19 relatives, 36 clinicians), with observations and documentary analysis in clinics in five hospitals in the UK undertaking major orthopaedic, colorectal, and/or cardiac surgery. RESULTS: Three opportunities for shared decision-making about major surgery were identified. Resolution-focused consultations (cardiac/colorectal) resulted in a single agreed preferred option related to a potentially life-threatening problem, with limited opportunities for shared decision-making. Evaluative and deliberative consultations offered more opportunity. The former focused on assessing the likelihood of benefits of surgery for a presenting problem that was not a threat to life for the patient (e.g., orthopaedic consultations) and the latter (largely colorectal) involved discussion of a range of options while also considering significant comorbidities and patient preferences. The extent to which opportunities for shared decision-making were available, and taken up by surgeons, was influenced by the nature of the presenting problem, clinical pathway, and patient trajectory. CONCLUSIONS: Decisions about major surgery were not always shared between patients and doctors. The nature of the presenting problem, comorbidities, clinical pathways, and patient trajectories all informed the type of consultation and opportunities for sharing decision-making. Our findings have implications for clinicians, with shared decision-making about major surgery most feasible when the focus is on life-enhancing treatment.

Early and long-term outcomes of conventional and valve-sparing aortic root replacement.

OBJECTIVE: To determine the early and long-term outcomes of conventional aortic root (ARR) and valve-sparing root replacement (VSRR) using a standard perioperative and operative approach. METHODS: We present prospectively collected data of 609 consecutive patients undergoing elective and urgent aortic root surgery (470 ARR, 139 VSRR) between 2006 and 2020. Primary outcomes were operative mortality and incidence of postoperative complications. Secondary outcomes were long-term survival and requirement for reintervention. Median follow-up was 7.6 years (range 0.5-14.5). RESULTS: 189 patients (31%) had bicuspid aortic valves and 17 (6.9%) underwent redo procedures. Median cross-clamp time was 88 (range 54-208) min with cardiopulmonary bypass of 108 (range 75-296) min. In-hospital mortality was 10 (1.6%), with transient ischaemic attacks/strokes occurring in 1.1%. In-hospital mortality for VSRR was 0.7%. 12 patients (2.0%) required a resternotomy for bleeding and 14 (2.3%) received haemofiltration. Intensive care unit and hospital stay were 1.7 and 7.0 days, respectively. During follow-up, redo surgery for native aortic valve replacement was required in 1.4% of the VSRR group. Overall survival was 95.1% at 3 years, 93.1% at 5 years, 91.2% at 7 years and 88.6% at 10 years. CONCLUSIONS: ARR and VSRR can be performed with low mortality and morbidity as well as a low rate of reintervention during the period of long-term follow-up, if performed by an experienced team with a consistent perioperative approach. This series provides contemporary evidence to balance the risks of aortic aneurysms and their rupture at diameters of <5.5 cm against the risks and benefits of surgery.

Relationship between indexed aortic area and aortic diameter in bicuspid aortic valve aortopathy: A retrospective cohort study.

BACKGROUND: Aortic dissection is a life-threatening complication of bicuspid aortic valve (BAV)-associated aortopathy. In these populations, whilst prophylactic replacement of proximal thoracic aortic aneurysms (TAAs) is generally recommended at threshold diameters ≥5.5 cm, dissection may occur in smaller aortas. An alternative size-based parameter, the cross-sectional aortic area/patient height ratio (indexed aortic area, IAA), correlates with increased dissection risk at abnormal values > 10 cm2/m. We sought to assess the utility of the IAA in identifying at-risk BAV-associated TAAs with abnormal IAA, albeit with sub-threshold aortic diameter. MATERIALS AND METHODS: We retrospectively identified 69 patients with BAV-associated TAAs who underwent surgical repair between 2010 and 2016. Aortic diameter was measured on pre-operative imaging, and IAA calculated, at the mid-sinus of Valsalva, sino-tubular junction and mid-ascending aorta for each patient. We determined proportions of aneurysms with IAA >10 cm2/m, median IAAs corresponding to aortic diameters <4.0 cm, 4.0-4.5 cm, 4.5-5.0 cm, 5.0-5.5 cm and >5.5 cm, and median aortic diameters corresponding to an abnormal IAA. RESULTS: 50.9%, 12.5% and 64.6% of aneurysms at the sinus of Valsalva, sino-tubular junction and mid-ascending aorta, respectively, had an abnormal IAA. 51.9% and 88.9% of patients with aortic diameter 4.5-5.0 cm and 5.0-5.5 cm, respectively, had an abnormal IAA. In aneurysms with abnormal IAA involving the sinus of Valsalva, sino-tubular junction, and mid-ascending aorta, median aortic diameters were 4.98 cm, 5.04 cm and 5.11 cm, respectively. Overall, 57/72 (79.2%) at-risk aneurysms with IAA >10 cm2/m had diameters smaller than the 5.5 cm guideline cut-off for surgical intervention. CONCLUSION: Significant proportions of BAV-associated TAAs are at increased risk of aortic dissection attending an IAA >10 cm2/m, whilst not fulfilling the size criteria indicating aortic surgery in contemporary guidelines. Further analysis of IAA in larger BAV cohorts is necessary to clarify its role in patient selection and optimal timing for prophylactic aortic replacement.

Effect of losartan on performance and physiological responses to exercise at high altitude (5035 m).

OBJECTIVE: Altitude-related and exercise-related elevations in blood pressure (BP) increase the likelihood of developing pulmonary hypertension and high-altitude illness during high-altitude sojourn. This study examined the antihypertensive effect and potential exercise benefit of the angiotensin II receptor antagonist losartan when taken at altitude. METHODS: Twenty participants, paired for age and ACE genotype status, completed a double-blinded, randomised study, where participants took either losartan (100 mg/day) or placebo for 21 days prior to arrival at 5035 m (Whymper Hut, Mt Chimborazo, Ecuador). Participants completed a maximal exercise test on a supine cycle ergometer at sea level (4 weeks prior) and within 48 hours of arrival to 5035 m (10-day ascent). Power output, beat-to-beat BP, oxygen saturation (SpO2) and heart rate (HR) were recorded during exercise, with resting BP collected from daily medicals during ascent. Before and immediately following exercise at 5035 m, extravascular lung water prevalence was assessed with ultrasound (quantified via B-line count). RESULTS: At altitude, peak power was reduced relative to sea level (p<0.01) in both groups (losartan vs placebo: down 100±29 vs 91±28 W, p=0.55), while SpO2 (70±6 vs 70±5%, p=0.96) and HR (146±21 vs 149±24 bpm, p=0.78) were similar between groups at peak power, as was the increase in systolic BP from rest to peak power (up 80±37 vs 69±33 mm Hg, p=0.56). Exercise increased B-line count (p<0.05), but not differently between groups (up 5±5 vs 8±10, p=0.44). CONCLUSION: Losartan had no observable effect on resting or exercising BP, exercise-induced symptomology of pulmonary hypertension or performance at 5035 m.

Understanding decision making about major surgery: protocol for a qualitative study of shared decision making by high-risk patients and their clinical teams.

INTRODUCTION: Surgical treatments are being offered to more patients than ever before, and increasingly to high-risk patients (typically multimorbid and over 75). Shared decision making is seen as essential practice. However, little is currently known about what 'good' shared decision making involves nor how it applies in the context of surgery for high-risk patients. This new study aims to identify how high-risk patients, their families and clinical teams negotiate decision making for major surgery. METHODS AND ANALYSIS: Focusing on major joint replacement, colorectal and cardiac surgery, we use qualitative methods to explore how patients, their families and clinicians negotiate decision making (including interactional, communicative and informational aspects and the extent to which these are perceived as shared) and reflect back on the decisions they made. Phase 1 involves video recording 15 decision making encounters about major surgery between patients, their carers/families and clinicians; followed by up to 90 interviews (with the same patient, carer and clinician participants) immediately after a decision has been made and again 3-6 months later. Phase 2 involves focus groups with a wider group of (up to 90) patients and (up to 30) clinicians to test out emerging findings and inform development of shared decision making scenarios (3-5 summary descriptions of how decisions are made). ETHICS AND DISSEMINATION: The study forms the first part in a 6-year programme of research, Optimising Shared decision-makIng for high-RIsk major Surgery (OSIRIS). Ethical challenges around involving patients at a challenging time in their lives will be overseen by the programme steering committee, which includes strong patient representation and a lay chair. In addition to academic outputs, we will produce a typology of decision making scenarios for major surgery to feed back to patients, professionals and service providers and inform subsequent work in the OSIRIS programme.

Hypoxia is not the primary mechanism contributing to exercise-induced proteinuria.

INTRODUCTION: Proteinuria increases at altitude and with exercise, potentially as a result of hypoxia. Using urinary alpha-1 acid glycoprotein (α1-AGP) levels as a sensitive marker of proteinuria, we examined the impact of relative hypoxia due to high altitude and blood pressure-lowering medication on post-exercise proteinuria. METHODS: Twenty individuals were pair-matched for sex, age and ACE genotype. They completed maximal exercise tests once at sea level and twice at altitude (5035 m). Losartan (100 mg/day; angiotensin-receptor blocker) and placebo were randomly assigned within each pair 21 days before ascent. The first altitude exercise test was completed within 24-48 hours of arrival (each pair within ~1 hour). Acetazolamide (125 mg two times per day) was administrated immediately after this test for 48 hours until the second altitude exercise test. RESULTS: With placebo, post-exercise α1-AGP levels were similar at sea level and altitude. Odds ratio (OR) for increased resting α1-AGP at altitude versus sea level was greater without losartan (2.16 times greater). At altitude, OR for reduced post-exercise α1-AGP (58% lower) was higher with losartan than placebo (2.25 times greater, p=0.059) despite similar pulse oximetry (SpO2) (p=0.95) between groups. Acetazolamide reduced post-exercise proteinuria by approximately threefold (9.3±9.7 vs 3.6±6.0 µg/min; p=0.025) although changes were not correlated (r=-0.10) with significant improvements in SpO2 (69.1%±4.5% vs 75.8%±3.8%; p=0.001). DISCUSSION: Profound systemic hypoxia imposed by altitude does not result in greater post-exercise proteinuria than sea level. Losartan and acetazolamide may attenuate post-exercise proteinuria, however further research is warranted.

Does the Aortic Annulus Dilate After Aortic Root Remodeling?

BACKGROUND: The 2 main techniques of valve-sparing aortic root replacement (VSRR) are remodeling and reimplantation. There is concern that the aortic annulus, which is not stabilized in remodeling technique, may dilate over time and cause aortic regurgitation. Our aim was to assess whether the aortic annulus dilates after VSRR with remodeling technique without aortic annuloplasty. METHODS: Data on patients undergoing elective or urgent VSRR remodeling technique between 2005 and 2018 were collected. Patients undergoing arch and emergency surgery for acute type A aortic dissection were excluded. Preoperative aortic annulus diameter was measured by transthoracic echocardiography, and this was compared with the annulus diameter measured from the most recently available transthoracic echocardiography. The requirement for reintervention during follow-up was recorded. RESULTS: Between 2005 and 2018, 98 patients underwent VSRR. Sixty-six (67.3%) had Marfan syndrome or Loeys-Dietz syndrome. Median age was 60 (interquartile range, 18-68) years and 71 (72.4%) were men. Median cross-clamp and cardiopulmonary bypass times were 122 (interquartile range, 104-164) minutes and 138 (interquartile range, 121-198) minutes, respectively. Median intensive care unit and hospital stay were 1 day and 6 days, respectively. No patients suffered perioperative stroke. There was no in-hospital mortality. At median follow-up of 7.1 years (interquartile range, 5-129 months), mean postoperative annular diameter was 25.7 mm, from 24.2 mm preoperatively (P = .403). One patient required aortic valve replacement during follow-up. Freedom from moderate or severe aortic regurgitation was 97%. CONCLUSIONS: There was no significant aortic annular dilatation in selected patients undergoing remodeling VSRR. Our data do not support routine use of annuloplasty in patients with annular diameter less than or equal to 25 mm.

A diver's guide to subaquatic envenomation in the Mediterranean.

INTRODUCTION: Between 40,000 and 50,000 divers and swimmers are envenomated each year and diving as a hobby is becoming increasingly popular. In the Mediterranean, envenomation is most often by Weever fish, Scorpion fish and jellyfish but coral and sea urchins may also be venomous. ENVENOMATION: Most stings cause local inflammation, oedema and pain. The severity of pain varies with the venom and the amount injected. In severe cases, stings may be life-threatening due to cardiogenic or anaphylactic shock or penetration of vital structures. MANAGEMENT: Most cases of envenomation are preventable with a combination of measures including the avoidance of contact through good buoyancy control, the wearing of body-suits, and by maintaining visual awareness. Immediate management is to return to the surface, elevate and wash the site of injury. Immersion in hot water followed by simple analgesics for pain relief has been shown to be more effective than other methods. More severe cases should be identified by symptoms including confusion and heavy bleeding and referred to qualified medical care. CONCLUSION: Envenomation by subaquatic species is common and preventable yet the dissemination of the appropriate knowledge is limited. This knowledge summary provides pertinent information aimed at divers in preventing and managing such injuries.

The influence of prolonged intensive care stay on quality of life, recovery, and clinical outcomes following cardiac surgery: A prospective cohort study.

OBJECTIVE: To examine the influence of prolonged intensive care unit (ICU) stay on quality of life and recovery following cardiac surgery. METHODS: Quality of life was assessed using the Short Form 36 Health Survey (SF36). The Postoperative Quality of Recovery Scale was used to assess quality of recovery, disability, and cognition after ICU discharge over 12 months' follow-up. Prolonged ICU stay was defined as ≥3 postoperative days. Mortality and major adverse cardiac and cerebrovascular events were recorded up to 12 months. RESULTS: For quality of life, the physical component improved over time in both groups (P < .01 for both groups), as did the mental component (P < .01 for both groups). The long ICU group had lower physical and mental components over time (both P values < .01), but by 12 months the values were similar. The overall quality of recovery was lower for the long ICU group (P < .01). Likewise, we found higher rates of recovery in the normal ICU group than in the long ICU group in terms of emotive recovery (P < .01), activities of daily living (P < .01), and cognitive recovery (P = .03) but no differences in terms of physiologic (P = .91), nociceptive (P = .89), and satisfaction with anesthetic care (P = .91). Major adverse cardiac and cerebrovascular events (P < .01), 30-day mortality (P < .01), and length of ward stay (P < .01) were all higher with prolonged ICU stay. CONCLUSIONS: Patients with prolonged ICU stay have lower quality of life scores; however, they achieve similar midterm quality of recovery, but with reduced survival, increased major adverse cardiac and cerebrovascular events, and longer hospital length of stay.

Fate of the Aortic Arch Following Surgery on the Aortic Root and Ascending Aorta in Bicuspid Aortic Valve.

BACKGROUND: Recent guidelines support more aggressive surgery for aneurysms of the ascending aorta and root in patients with bicuspid aortic valve. However, the fate of the arch after surgery of the root and ascending aorta is unknown. We set out to assess outcomes following root and ascending aortic surgery and subsequent growth of the arch. METHODS: Between 2005 and 2016, 536 consecutive patients underwent surgery for aneurysm of the root and ascending aorta; 168 had bicuspid aortic valve. Patients with dissection were excluded. Arch diameter was measured before and after surgery, at 6 months and then annually. RESULTS: Of 168 patients, 127 (75.6%) had aortic root replacement and 41 (24.4%) had ascending replacement. Mean age was 57 ± 12.8 years, 82.7% were men, and 5 operations were performed during pregnancy. There was 1 (0.6%) hospital death. One (0.6%) patient had a stroke and 1 (0.6%) had resternotomy for bleeding. Median intensive care unit and hospital stays were 1 and 6 days, respectively. Follow-up was complete for 94% at a median of 5.9 years (range, 1 to 139 months). Aortic arch diameter was 2.9 cm preoperatively and 3.0 cm at follow-up. There was 97% freedom from reoperation and none of the patients required surgery on the arch. CONCLUSIONS: Prophylactic arch replacement during aortic root and ascending aortic surgery in patients with bicuspid aortic valve is not supported. Our data do not support long-term surveillance of the rest of the aorta in this population.

Analysis of aortic area/height ratio in patients with thoracic aortic aneurysm and Type A dissection.

OBJECTIVES: Significant proportions of aortic dissections occur at aortic diameters <5.5 cm. By indexing aortic area to height and correlating with absolute aortic diameter, we sought to identify those aneurysm patients with aortic diameters <5.5 cm who do not meet current size thresholds for surgery, yet with corresponding abnormal indexed aortic areas (IAAs) >10 cm2/m, are at increased risk of aortic complications. METHODS: IAAs were calculated at 3 aortic locations in 187 aneurysm and 66 dissection patients operated on between 2010 and 2016 at our tertiary aortic centre. Proportions of patients with IAA >10 cm2/m, mean IAAs corresponding to aortic diameters <4.0 cm, 4.0-4.5 cm, 4.5-5.0 cm, 5.0-5.5 cm and >5.5 cm, and mean aortic diameters corresponding to IAAs 10-12 cm2/m, 12-14 cm2/m and >14 cm2/m were determined. RESULTS: Proportions of patients with abnormal IAAs were similar in both groups. In all, 49.1% of aneurysm patients with aortic diameters 4.5-5.0 cm, and 98.5% with aortic diameters 5.0-5.5 cm had abnormal IAAs. Out of 200 separate aneurysms with IAAs >10 cm2/m between the mid-sinus and mid-ascending aorta, 139 (69.5%) would not warrant surgery according to existing guidelines. CONCLUSIONS: Using the IAA, we identified a significant proportion of patients with thoracic aortic aneurysms who are at increased risk of aortic complications, despite current aortic guidelines not endorsing surgical intervention in this group. Our data suggests the IAA may be useful in preoperative risk evaluation and as a criterion for surgery.

Over-the-counter natural products in cardiac surgery: a case of ginseng-related massive perioperative bleeding.

We present a case of massive perioperative bleeding due to severe coagulopathy following urgent aortic and mitral valve replacement. Bleeding was persistent despite prolonged and meticulous surgical haemostasis and required high-volume blood products transfusions. No obvious cause was found to justify the severity of the coagulopathy, which was later attributed to high preoperative intake of ginseng.This case highlights the powerful activity of certain over-the-counter remedies on haemostasis, in this particular case on coagulation status. This also reminds us the paramount importance of a sound and comprehensive drug history for surgical patients.

Caudwell Xtreme Everest: A prospective study of the effects of environmental hypoxia on cognitive functioning.

BACKGROUND: The neuropsychological consequences of exposure to environmental hypobaric hypoxia (EHH) remain unclear. We thus investigated them in a large group of healthy volunteers who trekked to Mount Everest base camp (5,300 m). METHODS: A neuropsychological (NP) test battery assessing memory, language, attention, and executive function was administered to 198 participants (age 44.5±13.7 years; 60% male). These were studied at baseline (sea level), 3,500 m (Namche Bazaar), 5,300 m (Everest Base Camp) and on return to 1,300 m (Kathmandu) (attrition rate 23.7%). A comparable control group (n = 25; age 44.5±14.1 years; 60% male) for comparison with trekkers was tested at/or near sea level over an equivalent timeframe so as to account for learning effects associated with repeat testing. The Reliable Change Index (RCI) was used to calculate changes in cognition and neuropsychological function during and after exposure to EHH relative to controls. RESULTS: Overall, attention, verbal ability and executive function declined in those exposed to EHH when the performance of the control group was taken into account (RCI .05 to -.95) with decline persisting at descent. Memory and psychomotor function showed decline at highest ascent only (RCI -.08 to -.56). However, there was inter-individual variability in response: whilst NP performance declined in most, this improved in some trekkers. Cognitive decline was greater amongst older people (r = .42; p < .0001), but was otherwise not consistently associated with socio-demographic, mood, or physiological variables. CONCLUSIONS: After correcting for learning effects, attention, verbal abilities and executive functioning declined with exposure to EHH. There was considerable individual variability in the response of brain function to sustained hypoxia with some participants not showing any effects of hypoxia. This might have implications for those facing sustained hypoxia as a result of any disease.

Aortic Root Surgery: Does High Surgical Volume and a Consistent Perioperative Approach Improve Outcome?

There is evidence that high surgical volume and team consistency improve outcomes. Mortality of 4%-12% for aortic root surgery has been reported in the United States and UK. We aim to assess outcomes of patients undergoing aortic root surgery by a consistent, high-volume team. Data on patients undergoing elective or urgent aortic root replacement (ARR) were collected prospectively. Patients undergoing emergency surgery were excluded. A standardized perioperative approach was maintained and was achieved by delivering training to team members, including surgical trainees, anesthetic, nursing, and perfusion staff, whenever there was a change of team. Between 2005 and 2014, 344 patients underwent ARR. Median age was 59 years (18-86) and 74% were men. Procedures included ARR (biological [186; 54%] or mechanical [101; 29.4%]) and valve sparing root replacement, remodeling technique (57; 16.6%). A total of 42 patients (12.2%) underwent concomitant procedures. There were 4 (1.2%) in-hospital deaths and no incidence of stroke. In total, 3 (0.9%) required resternotomy for bleeding and 8 (2.3%) required hemofiltration. Follow-up was complete for 94% of patients with median intensive care unit and hospital stays of 1 and 6 days, respectively. Follow-up was complete for 94% of patients at a median of 5.6 years with 98% freedom from reoperation and prosthetic valve dysfunction. There was 90% freedom from aortic insufficiency at 7 years in the valve sparing root replacement, remodeling technique cohort. We have demonstrated that high surgical volume and standardized care improves outcomes in aortic root surgery. Maintaining a consistent perioperative approach ensures team members are aware and well rehearsed in their roles, thereby improving outcomes.

Predictors of Failure in Fast-Track Cardiac Surgery.

OBJECTIVES: Fast-track (FT) management of cardiac surgery patients is associated with early extubation and reduced length of intensive care unit (ICU) stay, with potential benefit of reduced hospital costs. The authors examined perioperative factors and their influence on failure of FT and what implications this failure had. DESIGN: Prospective data collection from all adult cardiac surgeries between 2011 and 2013. SETTING: Single-institution study. PARTICIPANTS: The study included 2,770 consecutive adult cardiac surgery patients. INTERVENTIONS: All participants underwent adult cardiac surgeries. Of those, 451 (16.3%) patients were selected to undergo FT management. MEASUREMENTS AND MAIN RESULTS: Failure of FT was defined as early (admission to ICU on day of surgery) or late (patients later admitted to the ICU from the ward). Univariate and multivariate regression analyses were used to identify which variables predicted FT failure. Of the 451 patients included in this study, 138 (30.6%) failed the FT, with 115 (83.3%) early failures and 23 (16.7%) late failures. Predictors of failure were reduced renal function, hypertension, age, EuroSCORE, cardiopulmonary bypass time, first lactate or base deficit after surgery (all p<0.01), and cross-clamp time (p<0.05). Multivariate analysis showed that the strongest predictor of failure was glomerular filtration rate (GFR)<65 mL/min/BSA (sensitivity, 54%; specificity, 61%; likelihood ratio, 1.39; area under receiver operating characteristics curve, 0.59; 95% confidence interval, 0.53-0.64). Median length of hospital stay was longer for the failed group (5 v 7 days, p<0.001). There were no mortalities in any of the patients selected for FT. CONCLUSIONS: A number of perioperative factors are associated with failure to FT, the strongest predictor being GFR. Failure to FT can lead to significantly longer hospital stay.

Simulation-based learning of transesophageal echocardiography in cardiothoracic surgical trainees: A prospective, randomized study.

OBJECTIVES: The Intercollegiate Surgical Curriculum now recommends that cardiac surgical trainees should be able to understand and interpret transesophageal echocardiography images. However, cardiac surgical trainees receive limited formal transesophageal echocardiography training. The objective of this study was to assess the impact of simulation-based teaching versus more traditional operating room teaching on transesophageal echocardiography knowledge in cardiac surgical trainees. METHODS: A total of 25 cardiac surgical trainees with no formal transesophageal echocardiography learning experience were randomly assigned by computer to a study group receiving simulation-based transesophageal echocardiography teaching via the Heartworks (Inventive Medical, London, UK) simulator (n = 12) or a control group receiving transesophageal echocardiography teaching during elective cardiac surgery (n = 13). Each subject undertook a video-based test composed of 20 multiple choice questions on standard transesophageal echocardiography views before and after teaching. RESULTS: There was no significant difference in the pretest scores between the 2 groups (P = .89). After transesophageal echocardiography teaching, subjects within each group demonstrated a statistically significant improvement in transesophageal echocardiography knowledge. Although the subjects within the simulation group outperformed their counterparts in the operating room teaching group in the post-test scores, this difference was not significant (P = .14). CONCLUSIONS: Despite the familiarity with transesophageal echocardiography images during surgery, subjects in the simulation group performed at least as well as those in the operating room group. Surgical trainees will benefit from formal transesophageal echocardiography teaching incorporated into their training via either learning method.

Cerebral hemodynamics at altitude: effects of hyperventilation and acclimatization on cerebral blood flow and oxygenation.

OBJECTIVE: Alterations in cerebral blood flow (CBF) and cerebral oxygenation are implicated in altitude-associated diseases. We assessed the dynamic changes in CBF and peripheral and cerebral oxygenation engendered by ascent to altitude with partial acclimatization and hyperventilation using a combination of near-infrared spectroscopy, transcranial Doppler ultrasound, and diffuse correlation spectroscopy. METHODS: Peripheral (Spo2) and cerebral (Scto2) oxygenation, end-tidal carbon dioxide (ETCO2), and cerebral hemodynamics were studied in 12 subjects using transcranial Doppler and diffuse correlation spectroscopy (DCS) at 75 m and then 2 days and 7 days after ascending to 4559 m above sea level. After obtaining baseline measurements, subjects hyperventilated to reduce baseline ETCO2 by 50%, and a further set of measurements were obtained. RESULTS: Cerebral oxygenation and peripheral oxygenation showed a divergent response, with cerebral oxygenation decreasing at day 2 and decreasing further at day 7 at altitude, whereas peripheral oxygenation decreased on day 2 before partially rebounding on day 7. Cerebral oxygenation decreased after hyperventilation at sea level (Scto2 from 68.8% to 63.5%; P<.001), increased after hyperventilation after 2 days at altitude (Scto2 from 65.6% to 69.9%; P=.001), and did not change after hyperventilation after 7 days at altitude (Scto2 from 62.2% to 63.3%; P=.35). CONCLUSIONS: An intensification of the normal cerebral hypocapnic vasoconstrictive response occurred after partial acclimatization in the setting of divergent peripheral and cerebral oxygenation. This may help explain why hyperventilation fails to improve cerebral oxygenation after partial acclimatization as it does after initial ascent. The use of DCS is feasible at altitude and provides a direct measure of CBF indices with high temporal resolution.

Incidence and mechanisms of cerebral ischemia after transcatheter aortic valve implantation compared with surgical aortic valve replacement.

BACKGROUND: The most likely mechanisms of neurologic injury after transcatheter aortic valve implantation (TAVI) and aortic valve replacement (AVR) are cerebral embolization and hypoperfusion. We set out to determine potential mechanisms of neurologic injury after TAVI compared with AVR. METHODS: One hundred twenty-seven consecutive high-risk patients with severe aortic stenosis (AS) who underwent TAVI (n = 85) or AVR (n = 42) were studied. Transcranial Doppler ultrasound (TCD), cerebral oximetry, diffusion-weighted magnetic resonance imaging (DW-MRI) (before, 6 days, and 3 months after procedure), and neurocognitive assessment before and at 3 months were performed. RESULTS: Neurologic injury was not significantly different between TAVI and AVR at 1 (1.1% vs 2.2%, p = 0.25) and 3 months (4.7% vs 2.2%, p = 1). At 3 months, overall cognitive score was higher in AVR compared with TAVI when adjusted for baseline score; the estimated difference between groups was 0.63 (95% confidence interval 0.87% to 1.17%; p = 0.02). Cerebral embolic load was 212 (123 to 344) during AVR and 134 (76 to 244) during TAVI (p = 0.07). Cerebral oxygen desaturation during AVR (7.56 ± 2.16) was higher compared with TAVI (5.93 ± 2.47) (p < 0.01). Ischemic lesions measured by DW-MRI occurred in 76% of TAVI and 71% of AVR patients at 6 days (p = 0.69) and 63% and 39% at 3 months (p = 0.11). No significant association was found between cerebral emboli, cerebral oxygen desaturation, brain ischemic lesions, and general cognitive score. CONCLUSIONS: At 3 months follow-up, overall cognitive score was higher in AVR compared with TAVI, adjusted for baseline score. However, there was no difference in cerebral embolic load, ischemic lesions, and oxygen desaturation.