BACKGROUND Induction of general anaesthesia has many potential triggers for peri-operative myocardial ischaemia including the acute disturbance of blood gases that frequently follows alterations in breathing and ventilation patterns. Free-breathing oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) imaging may provide the opportunity to continuously quantify the impact of such triggers on myocardial oxygenation. OBJECTIVE To investigate the impact of breathing patterns that simulate induction of general anaesthesia on myocardial oxygenation in awake healthy adults using continuous OS-CMR imaging. DESIGN Prospective observational study. SETTING Single-centre university hospital. Recruitment from August 2020 to January 2022. PARTICIPANTS Thirty-two healthy volunteers younger than 45 years old were recruited. Data were analysed from n = 29 (69% male individuals). INTERVENTION Participants performed a simulated induction breathing manoeuvre consisting of 2.5 min paced breathing with a respiration rate of 14 breaths per minute, followed by 5 deep breaths, then apnoea for up to 60s inside a magnetic resonance imaging scanner (MRI). Cardiac images were acquired with the traditional OS-CMR sequence (OS bh-cine ), which requires apnoea for acquisition and with two free-breathing OS-CMR sequences: a high-resolution single-shot sequence (OS fb-ss ) and a real-time cine sequence (OS fb-rtcine ). MAIN OUTCOME MEASURES Myocardial oxygenation response at the end of the paced breathing period and at the 30 s timepoint during the subsequent apnoea, reflecting the time of successful intubation in a clinical setting. RESULTS The paced breathing followed by five deep breaths significantly reduced myocardial oxygenation, which was observed with all three techniques (OS bh-cine −6.0 ± 2.6%, OS fb-ss −12.0 ± 5.9%, OS fb-rtcine −5.4 ± 7.0%, all P < 0.05). The subsequent vasodilating stimulus of apnoea then significantly increased myocardial oxygenation (OS bh-cine 6.8 ± 3.1%, OS fb-ss 8.4 ± 5.6%, OS fb-rtcine 15.7 ± 10.0%, all P < 0.01). The free-breathing sequences were reproducible and were not inferior to the original sequence for any stage. CONCLUSION Breathing manoeuvres simulating induction of general anaesthesia cause dynamic alterations of myocardial oxygenation in young volunteers, which can be quantified continuously with free-breathing OS-CMR. Introducing these new imaging techniques into peri-operative studies may throw new light into the mechanisms of peri-operative perturbations of myocardial tissue oxygenation and ischaemia. VISUAL_ABSTRACT http://links.lww.com/EJA/A922

IntroductionAlthough oxygen is the most widely used drug in medicine, clinical practice and formal recommendations regarding oxygen administration during general anaesthesia (GA) remain inconsistent. Oxygen has potent vasoconstrictive properties which may also act on coronary vasculature. In patients with coronary artery disease (CAD), a population at increased risk for perioperative cardiac complications, hyperoxic vasoconstriction may potentially trigger myocardial ischaemia. One of the most sensitive and earliest markers of myocardial ischaemia is myocardial systolic dysfunction, which can be assessed by myocardial deformation analysis from transoesophageal echocardiography (TOE) cine loops, also known as strain. While strain has been traditionally mainly investigated in longitudinal orientation, more recent data also appreciate the role of circumferential strain analysis in short-axis images. We investigated whether global circumferential strain (GCS) analysis detects any effects on systolic function when marked hyperoxia is induced by use of FIO2=0.8 in anaesthetised CAD patients.MethodsFor this randomized, controlled crossover clinical trial, 106 CAD patients scheduled for elective coronary artery bypass graft surgery were prospectively recruited. After induction of general anaesthesia and prior to surgical incision, FIO2 was first titrated to either a normoxaemic (FIO2=0.3, SpO2 95-98%) or a hyperoxic state (FIO2=0.8). Thereafter, three left ventricular short axis cine loops (basal, mid-ventricular, apical) were acquired with TOE. The opposite FIO2 level was then targeted and a second set of TOE images loops in the identical views was acquired. Subendocardial GCS of the left ventricle was quantified by a blinded reader and compared between FIO2 levels (figures 1 and 2). Independently, the burden of CAD was calculated by counting the number of myocardial segments (AHA 16-segment model) perfused by vessels with angiographically defined stenoses.ResultsPatients were aged 66 (44-81) years, 87% male. The majority (59%) had 3-vessel disease, with 33% presenting with 2-vessel disease and 8% with single-vessel disease. Overall, GCS significantly worsened from -26.0±6.9% at normoxaemia to -25.5±7.2% at hyperoxia (p=0.042, n=98). Regression analysis indicated that patients with better GCS at normoxaemia (r=-0.312, p=0.002), and those with fewer myocardial segments subtended to coronary stenoses (r=-0.246, p=0.015) showed poorer GCS at hyperoxia.DiscussionLV systolic function of anaesthetised CAD patients as assessed by GCS analysis was, in general, better when inspired oxygen concentration was titrated to 30%. Nevertheless, patients with more myocardium at ischaemic risk and/or worse strain at normoxaemia showed better GCS at hyperoxic conditions. Consequently, for support of their LV function under GA, patients with CAD may benefit from individualized FIO2 titration based on the known amount of myocardium at risk and on their normoxaemic GCS.

Atrial function can be assessed using advancing cardiovascular magnetic resonance (CMR) post-processing methods: atrial feature tracking (FT) strain analysis or a long-axis shortening (LAS) technique. This study aimed to first compare the two FT and LAS techniques in healthy individuals and cardiovascular patients and then investigated how left (LA) and right atrial (RA) measurements are related to the severity of diastolic dysfunction or atrial fibrillation. Sixty healthy controls and 90 cardiovascular disease patients with coronary artery disease, heart failure, or atrial fibrillation, underwent CMR. LA and RA were analyzed for standard volumetry as well as for myocardial deformation using FT and LAS for the different functional phases (reservoir, conduit, booster). Additionally, ventricular shortening and valve excursion measurements were assessed with the LAS module. The measurements for each of the LA and RA phases were correlated (p < 0.05) between the two approaches, with the highest correlation coefficients occurring in the reservoir phase (LA: r = 0.83, p < 0.01, RA: r = 0.66, p < 0.01). Both methods demonstrated reduced LA (FT: 26 ± 13 • Assessing right and left atrial function with CMR feature tracking or long-axis shortening techniques yields similar measurements and could potentially be used interchangeably based on the software capabilities of individual sites. • Atrial deformation and/or long-axis shortening allow for early detection of subtle atrial myopathy in diastolic dysfunction, even when atrial enlargement is not yet apparent. • Using a CMR-based analysis to understand the individual atrial-ventricular interaction in addition to tissue characteristics allows for a comprehensive interrogation of all four heart chambers. In patients, this could add clinically meaningful information and potentially allow for optimal therapies to be chosen to better target the dysfunction.

IntroductionThe cardiovascular system is vulnerable to effects associated with induction of general anaesthesia (GA). Novel free-breathing cardiovascular magnetic resonance (CMR) techniques can now image rapid fluctuations in tissue oxygenation and wall function of the myocardium beat-by-beat. This provides an excellent temporal resolution to spatially map myocardial oxygenation changes. We present interim findings from an innovative study applying oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) imaging to investigate the dynamics of myocardial oxygenation and function during the induction of GA in patients with and without coronary artery disease (CAD).MethodsFour patients without cardiovascular risk factors (no-CAD) scheduled for elective orthopaedic surgery (ASA-PS class I or II), and one patient with documented single-vessel CAD scheduled for elective minimally invasive direct coronary artery bypass surgery (ASA-PS class III) underwent GA induction inside an MRI scanner. OS-CMR imaging was applied continuously from the awake state throughout the entire induction process and for 10 minutes of anaesthesia maintenance, after which patients were transferred to their scheduled surgery. Changes in myocardial oxygenation were calculated in comparison to the awake state (%-change from baseline OS-CMR signal intensity). From these same images, myocardial function was quantified in a circumferential orientation using feature tracking strain analysis.ResultsFirst with pre-oxygenation (14 breaths/min paced breathing / FiO2=1.0), petCO2 (No-CAD:27±1mmHg, CAD:26mmHg) and myocardial oxygenation (No-CAD:-8.6±1.6% CAD:-8.8%) decreased in all patients. However, while the No-CAD patients showed an increase in myocardial contractility (strain:-16.3±1.1% to -17.5±11.7%), strain worsened during this phase in the CAD patient (-19.1% to -15.8%). With administration of sufentanil, breathing slowed with subsequent normalisation of petCO2 (No-CAD:37±2mmHg, CAD:35mmHg), myocardial oxygenation (no-CAD:2.4±4.1%, CAD:0.5%) and a partial recovery in strain (No-CAD:-15.1±0.3%, CAD:-16.8%). After propofol and rocuronium administration, manual bag ventilation led to another decrease in petCO2 (no-CAD:23±3mmHg, CAD:20mmHg), a decrease in myocardial oxygenation (No-CAD:-5.2±3.0, CAD:-11.0%), no change in strain in heart-healthy patients (-16.4±0.7%) but a decline in ventricular function in the CAD patient (strain=-15.0%). During maintenance (ventilation rate adjusted to target petCO2 35-40mmHg / FiO2=0.4) longer phases of myocardial de-oxygenation (OS-CMR<0%) were observed until 8.7±0.8min after intubation in the no-CAD patients, and until 8.5min in the CAD patient, respectively. By 10min after intubation, myocardial oxygenation had normalized to baseline levels but strain remained reduced (No-CAD:-14.0±10.5, CAD:-11.7%), likely due to direct cardio-depressant effects of sevoflurane. In the CAD patient, co-localized myocardial oxygenation and strain abnormalities were especially pronounced in the myocardial subtended to a haemodynamically significant stenosis, while No-CAD patients exhibited homogenous changes in the myocardium.DiscussionInterim results demonstrate that in the first study to ever use OS-CMR to monitor the heart during GA induction, complex fluctuations of myocardial oxygenation and function occur in patients with and without CAD. The patient with single-vessel CAD exhibited regional deoxygenation co-localized with myocardial strain deterioration in the territory at risk, indicative of inducible regional myocardial ischaemia. Implementation of advanced imaging in an anaesthesia research setting allows us to investigate how the heart responds to potential perioperative triggers of inducible ischaemia and may further advance the practice of anaesthesia for cardiac risk populations.

Background There are no current recommendations for oxygen titration in patients with stable coronary artery disease. This study investigates the effect of iatrogenic hyperoxia on cardiac function in patients with coronary artery disease undergoing general anaesthesia. Methods Patients scheduled for elective coronary artery bypass graft surgery were prospectively recruited into this randomised crossover clinical trial. All patients were exposed to inspired oxygen fractions of 0.3 (normoxaemia) and 0.8 (hyperoxia) in randomised order. A transoesophageal echocardiographic imaging protocol was performed during each exposure. Primary analysis investigated changes in 3D peak strain, whereas secondary analyses investigated other systolic and diastolic responses. Results There was no statistical difference in systolic function between normoxaemia and hyperoxia. However, the response in systolic function to hyperoxia was dependent on ventricular function at normoxaemia. Patients with a normoxaemic left ventricular (LV) global longitudinal strain (GLS) poorer than the derived cut-off (>-15.4%) improved with hyperoxia (P<0.01), whereas in patients with normoxaemic LV-GLS <-15.4%, LV-GLS worsened with transition to hyperoxia (P<0.01). The same was seen for right ventricular GLS with a cut-off at -24.1%. Diastolic function worsened during hyperoxia indicated by a significant increase of averaged E/e ' (8.6 [2.6]. vs 8.2 [2.4], P=0.01) and E/A ratio (1.4 (0.4) vs 1.3 (0.4), P=0.01). Conclusions Although the response of biventricular systolic variables is dependent on systolic function at normoxaemia, diastolic function consistently worsens under hyperoxia. In coronary artery disease, intraoperative strain analysis may offer guidance for oxygen titration.

Editor—In patients with cardiac disease, induction of general anaesthesia is a vulnerable phase, and it bears many potential triggers for provoking myocardial ischaemia. It involves changes in respiration, medications, tracheal intubation and initiation of positive-pressure ventilation, all of which can lead to rapid fluctuations in haemodynamics and arterial blood gases, with potential shifts in the myocardial oxygen supply–demand balance. 1 Priebe H.-J. Triggers of perioperative myocardial ischaemia and infarction. Br J Anaesth. 2004; 93: 9-20 Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar Perioperatively, the majority of myocardial injury can be attributed to oxygen-supply mismatch, 2 Puelacher C. Gualandro D.M. Glarner N. et al. Long-term outcomes of perioperative myocardial infarction/injury after non-cardiac surgery. Eur Heart J. 2023; : ehac798 Google Scholar which is often clinically silent yet one of the first stages of the ischaemic cascade. 3 Rafiudeen R. Barlis P. White H.D. van Gaal W. Type 2 MI and myocardial injury in the era of high-sensitivity troponin. Eur Cardiol Rev. 2022; 17: e03 Crossref PubMed Scopus (4) Google Scholar To our knowledge, the time course of myocardial oxygenation during induction of general anaesthesia has not been studied.

IntroductionPatients with coronary artery disease (CAD) undergoing general anesthesia are at risk of perioperative complications. Hyperoxia is a known coronary vasoconstrictor. However, it is also a pulmonary vasodilator, reducing right ventricular afterload. Thus, there may be competing effects of hyperoxia on right ventricular function. In this study we investigated the effects of hyperoxia and normoxia on right ventricular (RV) function assessed by 3D transesophageal echocardiography (TEE) during general anesthesia in CAD patients before elective coronary artery bypass graft surgery.MethodsIn this randomized clinical trial study participants (n=106) were prospectively recruited using a crossover design. In anesthetized patients the fraction of inspired oxygen (FiO2) was titrated to a normoxic state (FiO2=0.3) and a hyperoxic state (FiO2=0.8). At both states TEE images were acquired to assess RV ejection fraction (RVEF) and global longitudinal free-wall strain (RVGLS).ResultsThere was no difference between normoxia and hyperoxia in RVEF (46±6% vs. 45±8, p=0.504) nor in RVGLS (-22.4±4.8 vs. -21.9±4.3, p=0.352). However, RV function improved and worsened in some patients. ROC analysis (Figure A) shows that RVGLS at normoxia can better predict, which patients will worsen with excess oxygen. With a cut-off of -20% for RVGLS (Sensitivity: 87%, Specificity: 49%), it was demonstrated that hyperoxia was beneficial for patients with a poor strain at normoxia (>-20%) but detrimental for those with normal strain at normoxia (<-20%, Figure B), while RVEF with a cut-off of 40% (Sens: 88%, Spec: 33%) was unable to predict this response (Figure C.).ConclusionIn CAD patients undergoing general anaesthesia, hyperoxia has heterogenous effects on the RV and the potential detrimental effects of hyperoxia were best predicted by RVGLS. Intraoperative strain analysis might be a tool to target oxygen levels based on individual needs.

IntroductionIn patients with chronic coronary syndromes, hyperventilation followed by apnea has been shown to unmask myocardium susceptible to inducible deoxygenation. The aim of this study was to assess whether such a provoked response is co-localized with myocardial dysfunction.MethodsA group of twenty-six CAD patients with a defined stenosis (quantitative coronary angiography > 50%) underwent a cardiovascular magnetic resonance (CMR) exam prior to revascularization. Healthy volunteers older than 50 years served as controls (n = 12). Participants hyperventilated for 60s followed by brief apnea. Oxygenation-sensitive images were analyzed for changes in myocardial oxygenation and strain.ResultsIn healthy subjects, hyperventilation resulted in global myocardial deoxygenation (-10.2 ± 8.2%, p < 0.001) and augmented peak circumferential systolic strain (-3.3 ± 1.6%, p < 0.001). At the end of apnea, myocardial signal intensity had increased (+9.1 ± 5.3%, p < 0.001) and strain had normalized to baseline. CAD patients had a similar global oxygenation response to hyperventilation (−5.8 ± 9.6%, p = 0.085) but showed no change in peak strain from their resting state (-1.3 ± 1.6%), which was significantly attenuated in comparison the strain response observed in controls (p = 0.008). With apnea, the CAD patients showed an attenuated global oxygenation response to apnea compared to controls (+2.7 ± 6.2%, p < 0.001). This was accompanied by a significant depression of peak strain (3.0 ± 1.7%, p < 0.001), which also differed from the control response (p = 0.025). Regional analysis demonstrated that post-stenotic myocardium was most susceptible to de-oxygenation and systolic strain abnormalities during respiratory maneuvers. CMR measures at rest were unable to discriminate post-stenotic territory (p > 0.05), yet this was significant for both myocardial oxygenation [area under the curve (AUC): 0.88, p > 0.001] and peak strain (AUC: 0.73, p = 0.023) measured with apnea. A combined analysis of myocardial oxygenation and peak strain resulted in an incrementally higher AUC of 0.91, p < 0.001 than strain alone.ConclusionIn myocardium of patients with chronic coronary syndromes and primarily intermediate coronary stenoses, cine oxygenation-sensitive CMR can identify an impaired vascular and functional response to a vasoactive breathing maneuver stimulus indicative of inducible ischemia.

BackgroundPerioperative myocardial ischemia is associated with increased morbidity and mortality. General anesthesia (GA) bears many possible triggers for myocardial ischemia including acute blood gas changes. While cardiovascular magnetic resonance (CMR) is not feasible in an everyday intra-operative setting, its ability to measure myocardial oxygenation using oxygen-sensitive (OS) imaging provides a novel possibility to quantify tissue ischemia during the induction of GA in a research setting. However, OS-CMR is acquired during a breath-hold to reduce chest motion and requires up to 10s per image, and hence is not ideal for continuous monitoring. Thus, we optimized two free breathing OS-CMR sequence variants that acquire images every heartbeat to measure rapid changes in myocardial oxygenation. We aimed to compare these new sequences in an awake healthy control population performing voluntary hyperventilation and apnea. The intent of this analysis is to develop and validate this new CMR sequence for future studies implementing OS-CMR to measure myocardial oxygenation during GA.MethodsTwenty awake healthy participants underwent a CMR study and performed two breathing protocols. First a maneuver representing anesthesia pre-induction protocols was performed with paced breathing at 15bpm for 150s followed by 5 deep breaths and then apnea. Controls were then asked to perform a rapid paced maneuver consisting of 60s of deep hyperventilation at 30bpm for 60s, followed by a second apnea phase. During the procedure images were acquired with the original breath-hold (BH) OS-CMR sequence, the new free-breathing single shot (SS-FB) and real-time (RT-FB) sequences. The first is a single-shot variant that only acquires one image in diastole at a high resolution of 1.5mm2. The second is a real-time variant, that acquires 20 frames per second thus providing functional information throughout the cardiac cycle as well, but at a spatial resolution of 3mm2. Myocardial oxygenation was statistically compared at baseline, post hyperventilation which is a vasoconstricting stimulus, and at the 30s timepoint in apnea that is known to induce vasodilation.ResultsFor the first breathing pacing protocol representing GA induction, hyperventilation significantly reduced myocardial oxygenation with all three sequences (SS-FB: -12.1±10.6%, p<0.001, RT-FB: -8.0 ±4.0% p<0.001, BH: -4.2±3.7% p<0.001) and apnea resulted in a rise in myocardial oxygenation (SS-FB: 6.2±7.3% p=0.002, RT-FB: 11.8±4.1% p<0.001, BH: 6.9±5.7% p<0.001). With the rapid pacing maneuver similar results were observed with hyperventilation (SS-FB: -4.4±8.2% p=0.047, RT-FB: -7.0±1.8% p<0.001, BH: -4.3±6.2% p=0.008) and apnea (SS-FB: 9.2±6.5% p=<0.001, RT-FB: 9.1±2.1% p<0.001, BH: 4.5±5.0% p=0.001). The new SS-FB and RT-FB sequences were not inferior to the known gold standard BH sequence for any stage.ConclusionIn awake controls, alterations in myocardial oxygenation through hyperventilation and apnea can be observed with the novel free-breathing OS-CMR sequences. It is now warranted to implement these new techniques in future studies investigating peri-operative imaging of myocardial ischemia. Perioperative myocardial ischemia is associated with increased morbidity and mortality. General anesthesia (GA) bears many possible triggers for myocardial ischemia including acute blood gas changes. While cardiovascular magnetic resonance (CMR) is not feasible in an everyday intra-operative setting, its ability to measure myocardial oxygenation using oxygen-sensitive (OS) imaging provides a novel possibility to quantify tissue ischemia during the induction of GA in a research setting. However, OS-CMR is acquired during a breath-hold to reduce chest motion and requires up to 10s per image, and hence is not ideal for continuous monitoring. Thus, we optimized two free breathing OS-CMR sequence variants that acquire images every heartbeat to measure rapid changes in myocardial oxygenation. We aimed to compare these new sequences in an awake healthy control population performing voluntary hyperventilation and apnea. The intent of this analysis is to develop and validate this new CMR sequence for future studies implementing OS-CMR to measure myocardial oxygenation during GA. Twenty awake healthy participants underwent a CMR study and performed two breathing protocols. First a maneuver representing anesthesia pre-induction protocols was performed with paced breathing at 15bpm for 150s followed by 5 deep breaths and then apnea. Controls were then asked to perform a rapid paced maneuver consisting of 60s of deep hyperventilation at 30bpm for 60s, followed by a second apnea phase. During the procedure images were acquired with the original breath-hold (BH) OS-CMR sequence, the new free-breathing single shot (SS-FB) and real-time (RT-FB) sequences. The first is a single-shot variant that only acquires one image in diastole at a high resolution of 1.5mm2. The second is a real-time variant, that acquires 20 frames per second thus providing functional information throughout the cardiac cycle as well, but at a spatial resolution of 3mm2. Myocardial oxygenation was statistically compared at baseline, post hyperventilation which is a vasoconstricting stimulus, and at the 30s timepoint in apnea that is known to induce vasodilation. For the first breathing pacing protocol representing GA induction, hyperventilation significantly reduced myocardial oxygenation with all three sequences (SS-FB: -12.1±10.6%, p<0.001, RT-FB: -8.0 ±4.0% p<0.001, BH: -4.2±3.7% p<0.001) and apnea resulted in a rise in myocardial oxygenation (SS-FB: 6.2±7.3% p=0.002, RT-FB: 11.8±4.1% p<0.001, BH: 6.9±5.7% p<0.001). With the rapid pacing maneuver similar results were observed with hyperventilation (SS-FB: -4.4±8.2% p=0.047, RT-FB: -7.0±1.8% p<0.001, BH: -4.3±6.2% p=0.008) and apnea (SS-FB: 9.2±6.5% p=<0.001, RT-FB: 9.1±2.1% p<0.001, BH: 4.5±5.0% p=0.001). The new SS-FB and RT-FB sequences were not inferior to the known gold standard BH sequence for any stage. In awake controls, alterations in myocardial oxygenation through hyperventilation and apnea can be observed with the novel free-breathing OS-CMR sequences. It is now warranted to implement these new techniques in future studies investigating peri-operative imaging of myocardial ischemia.

Background: The pathophysiology of heart failure with preserved ejection fraction is not well understood, but evidence strongly suggests involvement of microvascular dysfunction. We studied the myocardial oxygenation reserve as a direct marker of coronary vascular function and its relation to myocardial deformation and tissue characteristics by cardiovascular magnetic resonance (CMR). Methods: In a dual-center case-control study, patients with heart failure and preserved ejection fraction (>50%) and healthy controls older than 50 years underwent quantitative CMR for ventricular volumes and functional assessment with feature tracking, as well as tissue characterization (T1, T2, extracellular volume). Coronary vascular function was measured by oxygenation-sensitive (OS)–CMR of the myocardial oxygenation response to a vasoactive breathing maneuver. Results: Twenty-nine patients completed the CMR exam. Compared with cutoffs derived from 12 control subjects, circumferential peak strain was attenuated in 97% of patients. Native T1 was elevated in 93%, extracellular volume was elevated in 83%. Sixty-six percent of patients revealed either regional or global myocardial edema, defined by an increased myocardial T2. An attenuated global myocardial oxygenation reserve (<4.4%) was observed in 96% of the patients (1.7±3.9% versus 9.1±5.3% in controls, P <0.001). This was correlated with septal wall thickness (r=−0.54, P =0.003), edema (myocardial T2; β=−0.26% oxygenation-sensitive/ms [95% CI, −0.49 to −0.03], P =0.029), and reduced diastolic strain rate (β=1.50% oxygenation-sensitive/s -1 [95% CI, 0.06–2.90], P =0.042). Conclusions: In patients with clinical heart failure with preserved ejection fraction, vascular dysfunction as measured by an attenuated myocardial oxygenation reserve is associated with myocardial edema, a thicker septum, and diastolic dysfunction. A quantitative comprehensive CMR exam including oxygenation-sensitive–CMR allows for comprehensive imaging-based phenotyping of heart failure with preserved ejection fraction.

Red blood cell salvage plays an important role in reducing the use of allogeneic blood transfusion during cardiac surgery. While there is consensus as to the benefit of employing cell salvage systems, there are no clear recommendations on the anticoagulant used for salvaged blood. In eight patients undergoing elective cardiac surgery at our university hospital's cardiovascular center, the authors describe hemodynamic effects of salvaged autologous blood transfusion when either unfractionated heparin or acid citrate dextrose formula A was used as the anticoagulant. Mean arterial pressure, heart rate, central venous pressure and acid-base status of the autologous red blood cell concentrate were compared between patients receiving autologous blood anticoagulated with acid citrate dextrose formula A versus unfractionated heparin. A clinically relevant decrease in mean arterial pressure (median change, - 19 mmHg [min -29; max -1] and marked acidosis [group median <6.30 [<6.30; 6.49] was observed in group acid citrate dextrose formula A. Acid citrate dextrose formula A anticoagulant for autologous red blood cell salvage has the potential to cause major adverse hemodynamic events during free-flowing re-transfusion of autologous red blood cell concentrate. Acute ionized hypocalcemia and acidemia may ensue from residual citrate in the supernatant of red blood cell concentrate reconstituted in unbuffered saline.

We present the case of a patient with infective endocarditis anesthetized for replacement of severely regurgitant aortic valve. Intraoperative transesophageal echocardiography revealed a new diagnosis of severe secondary mitral regurgitation. After aortic valve replacement and tricuspid valve repair, severe mitral regurgitation resolved rapidly without any intervention. In multivalvular disease, instant spontaneous resolution of secondary mitral regurgitation is possible after surgical correction of an aortic regurgitation causing left ventricular volume overload.

Perioperative visual loss is a rare but severe complication after surgery in prone position. One of several mechanisms is direct ophthalmic compression. This can be avoided through optimal positioning and padding of the head, but position and integrity of the eyes need to be checked at regular intervals. We describe the use of a conventional video laryngoscope during vascular surgery in prone position as a simple solution for intermittent monitoring of external integrity of the eyes and size of the pupils. This requires no additional material and allows documentation of the findings. Our method might reduce complications and improve patient outcome.

Transcatheter mitral valve implantation is an emerging technology for the treatment of inoperable or high-risk patients with symptomatic severe mitral regurgitation. Known technical issues are obstruction of the left ventricular outflow tract, paravalvular leakage, and hemolysis. We report a case of valve retensioning successfully resolving paravalvular leakage and hemolysis. (Level of Difficulty: Intermediate.)

BACKGROUND:Supplemental oxygen (O2) is used routinely during anesthesia. In the treatment of acute myocardial infarction, it has been established that hyperoxia is to be avoided, whereas information on benefit and risk of hyperoxia in patients with stable coronary artery disease (CAD) remain scarce, especially in the setting of general anesthesia. This study will compare the immediate effects of normoxemia and hyperoxia on cardiac function, with a primary focus on changes in peak longitudinal left-ventricular strain, in anesthetized stable chronic CAD patients using peri-operative transesophageal echocardiography (TEE). METHODS:A single-center randomized cross-over clinical trial will be conducted, enrolling 106 patients undergoing elective coronary artery bypass graft surgery. After the induction of anesthesia and prior to the start of surgery, cardiac function will be assessed by 2D and 3D TEE. Images will be acquired at two different oxygen states for each patient in randomized order. The fraction of inspired oxygen (FIO2) will be titrated to a normoxemic state (oxygen saturation of 95-98%) and adjusted to a hyperoxic state (FIO2 = 0.8). TEE images will be analyzed in a blinded manner for standard cardiac function and strain parameters. CONCLUSION:By using myocardial strain assessed by TEE, early and subtle signs of biventricular systolic and diastolic dysfunction can be promptly measured intraoperatively prior to the onset of severe signs of ischemia. The results may help anesthesiologists to better understand the effects of FIO2 on cardiac function and potentially tailor oxygen therapy to patients with CAD undergoing general anesthesia.

BACKGROUND:Extracorporeal cardiopulmonary resuscitation has become a recommended treatment option for patients with severe hypothermia with cardiac arrest. Minimal invasive extracorporeal circulation (MiECC) may offer advantages over the current standard extracorporeal membrane oxygenation (ECMO).METHODS:Retrospective cohort analysis of hospital database for patients with accidental hypothermia and extracorporeal rewarming with MiECC admitted between 2010 and 2019.RESULTS:Overall, six of 17 patients survived to hospital discharge. Eleven patients suffered accidental hypothermia in an alpine and six in an urban setting. Sixteen patients arrived at the hospital under ongoing cardiopulmonary resuscitation (CPR). CPR time was 90 minutes (0-150). Four patients survived from an alpine setting and two from an urban setting with CPR duration of 90 minutes (0-150) and 85 minutes (25-100), respectively. Asphyctic patients tended to have lower survival (one of seven patients). Two patients of six with major trauma survived.CONCLUSION:MiECC for extracorporeal rewarming from severe accidental hypothermia is a feasible alternative to ECMO, with comparable survival rates.