Midterm outcomes of venovenous extracorporeal membrane oxygenation as a bridge to lung transplantation: Comparison with nonbridged recipients.

OBJECTIVES: Venovenous extracorporeal membrane oxygenation (VV-ECMO) is increasingly being used in acutely deteriorating patients with end-stage lung disease as a bridge to transplantation (BTT). It can allow critically ill recipients to remain eligible for lung transplants (LTx) while reducing pretransplant deconditioning. We analyzed early- and midterm postoperative outcomes of patients on VV-ECMO as a BTT and the impact of preoperative VV-ECMO on posttransplant survival outcomes. METHODS: All consecutive LTx performed at our institution between January 2012 and December 2018 were analyzed. After matching, BTT patients were compared with nonbridged LTx recipients. RESULTS: Out of 297 transplanted patients, 21 (7.1%) were placed on VV-ECMO as a BTT. After matching, we observed similar 30-day mortality between BTT and non-BTT patients (4.6% vs. 6.6%, p = .083) despite a higher incidence of early postoperative complications (need for ECMO, delayed chest closure, and acute kidney injury). Furthermore, preoperative VV-ECMO did not appear associated with 30-day or 1-year mortality in both frequentist and Bayesian analysis (odds ratio [OR]: 0.35, 95% confidence interval: 0.03-3.49, p = .369; OR: 0.27, 95% credible interval: 0.01-3.82, p = 84.7%, respectively). In sensitivity analysis, both subgroups were similar in respect to 30-day (7.8% vs. 6.5%, p = .048) and 1-year mortality (12.5% vs. 18%, p = .154). CONCLUSIONS: Patients with acute refractory respiratory failure while waiting for LTx represent a high-risk cohort of patients. VV-ECMO as a BTT is a reasonable strategy in adult patients with acceptable operative mortality and 1-year survival comparable to non-BTT patients.

Cardiac Energetics in Patients With Aortic Stenosis and Preserved Versus Reduced Ejection Fraction.

BACKGROUND: Why some but not all patients with severe aortic stenosis (SevAS) develop otherwise unexplained reduced systolic function is unclear. We investigate the hypothesis that reduced creatine kinase (CK) capacity and flux is associated with this transition. METHODS: We recruited 102 participants to 5 groups: moderate aortic stenosis (ModAS) (n=13), SevAS, left ventricular (LV) ejection fraction ≥55% (SevAS-preserved ejection fraction, n=37), SevAS, LV ejection fraction <55% (SevAS-reduced ejection fraction, n=15), healthy volunteers with nonhypertrophied hearts with normal systolic function (normal healthy volunteer, n=30), and patients with nonhypertrophied, non-pressure-loaded hearts with normal systolic function undergoing cardiac surgery and donating LV biopsy (non-pressure-loaded heart biopsy, n=7). All underwent cardiac magnetic resonance imaging and 31P magnetic resonance spectroscopy for myocardial energetics. LV biopsies (AS and non-pressure-loaded heart biopsy) were analyzed for CK total activity, CK isoforms, citrate synthase activity, and total creatine. Mitochondria-sarcomere diffusion distances were calculated by using serial block-face scanning electron microscopy. RESULTS: In the absence of failure, CK flux was lower in the presence of AS (by 32%, P=0.04), driven primarily by reduction in phosphocreatine/ATP (by 17%, P<0.001), with CK kf unchanged (P=0.46). Although lowest in the SevAS-reduced ejection fraction group, CK flux was not different from the SevAS-preserved ejection fraction group (P>0.99). Accompanying the fall in CK flux, total CK and citrate synthase activities and the absolute activities of mitochondrial-type CK and CK-MM isoforms were also lower (P<0.02, all analyses). Median mitochondria-sarcomere diffusion distances correlated well with CK total activity (r=0.86, P=0.003). CONCLUSIONS: Total CK capacity is reduced in SevAS, with median values lowest in those with systolic failure, consistent with reduced energy supply reserve. Despite this, in vivo magnetic resonance spectroscopy measures of resting CK flux suggest that ATP delivery is reduced earlier, at the moderate AS stage, where LV function remains preserved. These findings show that significant energetic impairment is already established in moderate AS and suggest that a fall in CK flux is not by itself a necessary cause of transition to systolic failure. However, because ATP demands increase with AS severity, this could increase susceptibility to systolic failure. As such, targeting CK capacity and flux may be a therapeutic strategy to prevent and treat systolic failure in AS.

The impact of COVID-19 pandemic on aortic valve surgical service: a single centre experience.

BACKGROUND: The coronavirus-disease 2019 (COVID-19) pandemic imposed an unprecedented burden on the provision of cardiac surgical services. The reallocation of workforce and resources necessitated the postponement of elective operations in this cohort of high-risk patients. We investigated the impact of this outbreak on the aortic valve surgery activity at a single two-site centre in the United Kingdom. METHODS: Data were extracted from the local surgical database, including the demographics, clinical characteristics, and outcomes of patients operated on from March 2020 to May 2020 with only one of the two sites resuming operative activity and compared with the respective 2019 period. A similar comparison was conducted with the period between June 2020 and August 2020, when operative activity was restored at both institutional sites. The experience of centres world-wide was invoked to assess the efficiency of our services. RESULTS: There was an initial 38.2% reduction in the total number of operations with a 70% reduction in elective cases, compared with a 159% increase in urgent and emergency operations. The attendant surgical risk was significantly higher [median Euroscore II was 2.7 [1.9-5.2] in 2020 versus 2.1 [0.9-3.7] in 2019 (p = 0.005)] but neither 30-day survival nor freedom from major post-operative complications (re-sternotomy for bleeding/tamponade, transient ischemic attack/stroke, renal replacement therapy) was compromised (p > 0.05 for all comparisons). Recommencement of activity at both institutional sites conferred a surgical volume within 17% of the pre-COVID-19 era. CONCLUSIONS: Our institution managed to offer a considerable volume of aortic valve surgical activity over the first COVID-19 outbreak to a cohort of higher-risk patients, without compromising post-operative outcomes. A backlog of elective cases is expected to develop, the accommodation of which after surgical activity normalisation will be crucial to monitor.

Localized rest and stress human cardiac creatine kinase reaction kinetics at 3 T.

Changes in the kinetics of the creatine kinase (CK) shuttle are sensitive markers of cardiac energetics but are typically measured at rest and in the prone position. This study aims to measure CK kinetics during pharmacological stress at 3 T, with measurement in the supine position. A shorter "stressed saturation transfer" (StreST) extension to the triple repetition time saturation transfer (TRiST) method is proposed. We assess scanning in a supine position and validate the MR measurement against biopsy assay of CK activity. We report normal ranges of stress CK forward rate (kfCK ) for healthy volunteers and obese patients. TRiST measures kfCK in 40 min at 3 T. StreST extends the previously developed TRiST to also make a further kfCK measurement during <20 min of dobutamine stress. We test our TRiST implementation in skeletal muscle and myocardium in both prone and supine positions. We evaluate StreST in the myocardium of six healthy volunteers and 34 obese subjects. We validated MR-measured kfCK against biopsy assays of CK activity. TRiST kfCK values matched literature values in skeletal muscle (kfCK  = 0.25 ± 0.03 s-1 vs 0.27 ± 0.03 s-1 ) and myocardium when measured in the prone position (0.32 ± 0.15 s-1 ), but a significant difference was found for TRiST kfCK measured supine (0.24 ± 0.12 s-1 ). This difference was because of different respiratory- and cardiac-motion-induced B0 changes in the two positions. Using supine TRiST, cardiac kfCK values for normal-weight subjects were 0.15 ± 0.09 s-1 at rest and 0.17 ± 0.15 s-1 during stress. For obese subjects, kfCK was 0.16 ± 0.07 s-1 at rest and 0.17 ± 0.10 s-1 during stress. Rest myocardial kfCK and CK activity from LV biopsies of the same subjects correlated (R = 0.43, p = 0.03). We present an independent implementation of TRiST on the Siemens platform using a commercially available coil. Our extended StreST protocol enables cardiac kfCK to be measured during dobutamine-induced stress in the supine position.

Mutual Regulation of Epicardial Adipose Tissue and Myocardial Redox State by PPAR-γ/Adiponectin Signalling.

RATIONALE: Adiponectin has anti-inflammatory effects in experimental models, but its role in the regulation of myocardial redox state in humans is unknown. Although adiponectin is released from epicardial adipose tissue (EpAT), it is unclear whether it exerts any paracrine effects on the human myocardium. OBJECTIVE: To explore the cross talk between EpAT-derived adiponectin and myocardial redox state in the human heart. METHODS AND RESULTS: EpAT and atrial myocardium were obtained from 306 patients undergoing coronary artery bypass grafting. Functional genetic polymorphisms that increase ADIPOQ expression (encoding adiponectin) led to reduced myocardial nicotinamide adenine dinucleotide phosphate oxidase-derived O2 (-), whereas circulating adiponectin and ADIPOQ expression in EpAT were associated with elevated myocardial O2 (-). In human atrial tissue, we demonstrated that adiponectin suppresses myocardial nicotinamide adenine dinucleotide phosphate oxidase activity, by preventing AMP kinase-mediated translocation of Rac1 and p47(phox) from the cytosol to the membranes. Induction of O2 (-) production in H9C2 cardiac myocytes led to the release of a transferable factor able to induce peroxisome proliferator-activated receptor-γ-mediated upregulation of ADIPOQ expression in cocultured EpAT. Using a NOX2 transgenic mouse and a pig model of rapid atrial pacing, we found that oxidation products (such as 4-hydroxynonenal) released from the heart trigger peroxisome proliferator-activated receptor-γ-mediated upregulation of ADIPOQ in EpAT. CONCLUSIONS: We demonstrate for the first time in humans that adiponectin directly decreases myocardial nicotinamide adenine dinucleotide phosphate oxidase activity via endocrine or paracrine effects. Adiponectin expression in EpAT is controlled by paracrine effects of oxidation products released from the heart. These effects constitute a novel defense mechanism of the heart against myocardial oxidative stress.

Predictive value of telomere length on outcome following acute myocardial infarction: evidence for contrasting effects of vascular vs. blood oxidative stress.

AIMS: Experimental evidence suggests that telomere length (TL) is shortened by oxidative DNA damage, reflecting biological aging. We explore the value of blood (BTL) and vascular TL (VTL) as biomarkers of systemic/vascular oxidative stress in humans and test the clinical predictive value of BTL in acute myocardial infarction (AMI). METHODS AND RESULTS: In a prospective cohort of 290 patients surviving recent AMI, BTL measured on admission was a strong predictor of all-cause [hazard ratio (HR) [95% confidence interval (CI)]: 3.21 [1.46-7.06], P = 0.004] and cardiovascular mortality (HR [95% CI]: 3.96 [1.65-9.53], P = 0.002) 1 year after AMI (for comparisons of short vs. long BTL, as defined by a T/S ratio cut-off of 0.916, calculated using receiver operating characteristic analysis; P adjusted for age and other predictors). To explore the biological meaning of these findings, BTL was quantified in 727 consecutive patients undergoing coronary artery bypass grafting (CABG), and superoxide (O2.-) was measured in peripheral blood mononuclear cells (PBMNC). VTL/vascular O2.- were quantified in saphenous vein (SV) and mammary artery (IMA) segments. Patients were genotyped for functional genetic polymorphisms in P22ph°x (activating NADPH-oxidases) and vascular smooth muscle cells (VSMC) selected by genotype were cultured from vascular tissue. Short BTL was associated with high O2.- in PBMNC (P = 0.04) but not in vessels, whereas VTL was related to O2.- in IMA (ρ = -0.49, P = 0.004) and SV (ρ = -0.52, P = 0.01). Angiotensin II (AngII) incubation of VSMC (30 days), as a means of stimulating NADPH-oxidases, increased O2.- and reduced TL in carriers of the high-responsiveness P22ph°x alleles (P = 0.007). CONCLUSION: BTL predicts cardiovascular outcomes post-AMI, independently of age, whereas VTL is a tissue-specific (rather than a global) biomarker of vascular oxidative stress. The lack of a strong association between BTL and VTL reveals the importance of systemic vs. vascular factors in determining clinical outcomes after AMI.

Splenic T1-mapping: a novel quantitative method for assessing adenosine stress adequacy for cardiovascular magnetic resonance.

BACKGROUND: Perfusion cardiovascular magnetic resonance (CMR) performed with inadequate adenosine stress leads to false-negative results and suboptimal clinical management. The recently proposed marker of adequate stress, the "splenic switch-off" sign, detects splenic blood flow attenuation during stress perfusion (spleen appears dark), but can only be assessed after gadolinium first-pass, when it is too late to optimize the stress response. Reduction in splenic blood volume during adenosine stress is expected to shorten native splenic T1, which may predict splenic switch-off without the need for gadolinium. METHODS: Two-hundred and twelve subjects underwent adenosine stress CMR: 1.5 T (n = 104; 75 patients, 29 healthy controls); 3 T (n = 108; 86 patients, 22 healthy controls). Native T1spleen was assessed using heart-rate-independent ShMOLLI prototype sequence at rest and during adenosine stress (140 µg/kg/min, 4 min, IV) in 3 short-axis slices (basal, mid-ventricular, apical). This was compared with changes in peak splenic perfusion signal intensity (ΔSIspleen) and the "splenic switch-off" sign on conventional stress/rest gadolinium perfusion imaging. T1spleen values were obtained blinded to perfusion ΔSIspleen, both were derived using regions of interest carefully placed to avoid artefacts and partial-volume effects. RESULTS: Normal resting splenic T1 values were 1102 ± 66 ms (1.5 T) and 1352 ± 114 ms (3 T), slightly higher than in patients (1083 ± 59 ms, p = 0.04; 1295 ± 105 ms, p = 0.01, respectively). T1spleen decreased significantly during adenosine stress (mean ΔT1spleen ~ -40 ms), independent of field strength, age, gender, and cardiovascular diseases. While ΔT1spleen correlated strongly with ΔSIspleen (rho = 0.70, p < 0.0001); neither indices showed significant correlations with conventional hemodynamic markers (rate pressure product) during stress. By ROC analysis, a ΔT1spleen threshold of ≥ -30 ms during stress predicted the "splenic switch-off" sign (AUC 0.90, p < 0.0001) with sensitivity (90%), specificity (88%), accuracy (90%), PPV (98%), NPV (42%). CONCLUSIONS: Adenosine stress and rest splenic T1-mapping is a novel method for assessing stress responses, independent of conventional hemodynamic parameters. It enables prediction of the visual "splenic switch-off" sign without the need for gadolinium, and correlates well to changes in splenic signal intensity during stress/rest perfusion imaging. ΔT1spleen holds promise to facilitate optimization of stress responses before gadolinium first-pass perfusion CMR.

Mortality in patients treated with extended duration dual antiplatelet therapy after drug-eluting stent implantation: a pairwise and Bayesian network meta-analysis of randomised trials.

BACKGROUND: Despite recent studies, the optimum duration of dual antiplatelet therapy (DAPT) after coronary drug-eluting stent placement remains uncertain. We performed a meta-analysis with several analytical approaches to investigate mortality and other clinical outcomes with different DAPT strategies. METHODS: We searched Medline, Embase, Cochrane databases, and proceedings of international meetings on Nov 20, 2014, for randomised controlled trials comparing different DAPT durations after drug-eluting stent implantation. We extracted study design, inclusion and exclusion criteria, sample characteristics, and clinical outcomes. DAPT duration was categorised in each study as shorter versus longer, and as 6 months or shorter versus 1 year versus longer than 1 year. Analyses were done by both frequentist and Bayesian approaches. FINDINGS: We identified ten trials published between Dec 16, 2011, and Nov 16, 2014, including 31,666 randomly assigned patients. By frequentist pairwise meta-analysis, shorter DAPT was associated with significantly lower all-cause mortality compared with longer DAPT (HR 0·82, 95% CI 0·69-0·98; p=0·02; number needed to treat [NNT]=325), with no significant heterogeneity apparent across trials. The reduced mortality with shorter compared with longer DAPT was attributable to lower non-cardiac mortality (0·67, 0·51-0·89; p=0·006; NNT=347), with similar cardiac mortality (0·93, 0·73-1·17; p=0.52). Shorter DAPT was also associated with a lower risk of major bleeding, but a higher risk of myocardial infarction and stent thrombosis. We noted similar results in a Bayesian framework with non-informative priors. By network meta-analysis, patients treated with 6-month or shorter DAPT and 1-year DAPT had higher risk of myocardial infarction and stent thrombosis but lower risk of mortality compared with patients treated with DAPT for longer than 1 year. Patients treated with DAPT for 6 months or shorter had similar rates of mortality, myocardial infarction, and stent thrombosis, but lower rates of major bleeding than did patients treated with 1-year DAPT. INTERPRETATION: Although treatment with DAPT beyond 1 year after drug-eluting stent implantation reduces myocardial infarction and stent thrombosis, it is associated with increased mortality because of an increased risk of non-cardiovascular mortality not offset by a reduction in cardiac mortality. FUNDING: None.

Mitral Valve Diverticulum Presenting with Severe Mitral Stenosis: Case Report.

The case is presented of a non-infectious anterior mitral valve leaflet diverticulum, which appeared as symptomatic mitral stenosis. Unlike previous reports, there was no histological myxomatous degeneration of the valve. To the authors' knowledge, this is the first time a mitral valve diverticulum resulting in severe mitral stenosis has been reported in the literature.

Reciprocal effects of systemic inflammation and brain natriuretic peptide on adiponectin biosynthesis in adipose tissue of patients with ischemic heart disease.

OBJECTIVE: To explore the role of systemic inflammation in the regulation of adiponectin levels in patients with ischemic heart disease. APPROACH AND RESULTS: In a cross-sectional study of 575 subjects, serum adiponectin was compared between healthy subjects, patients with coronary artery disease with no/mild/severe heart failure (HF), and patients with nonischemic HF. Adiponectin expression and release from femoral, subcutaneous and thoracic adipose tissue was determined in 258 additional patients with coronary artery bypass grafting. Responsiveness of the various human adipose tissue depots to interleukin-6, tumor necrosis factor-α, and brain natriuretic peptide (BNP) was examined by using ex vivo models of human fat. The effects of inducible low-grade inflammation were tested by using the model of Salmonella typhi vaccine-induced inflammation in healthy individuals. In the cross-sectional study, HF strikingly increased adiponectin levels. Plasma BNP was the strongest predictor of circulating adiponectin and its release from all adipose tissue depots in patients with coronary artery bypass grafting, even in the absence of HF. Femoral AT was the depot with the least macrophages infiltration and the largest adipocyte cell size and the only responsive to systemic and ex vivo proinflammatory stimulation (effect reversible by BNP). Low-grade inflammation reduced circulating adiponectin levels, while circulating BNP remained unchanged. CONCLUSIONS: This study demonstrates the regional variability in the responsiveness of human adipose tissue to systemic inflammation and suggests that BNP (not systemic inflammation) is the main driver of circulating adiponectin in patients with advanced atherosclerosis even in the absence of HF. Any interpretation of circulating adiponectin as a biomarker should take into account the underlying disease state, background inflammation, and BNP levels.

Type A aortic dissection after nonaortic cardiac surgery.

BACKGROUND: Cardiac surgery with cardiopulmonary bypass is associated with mechanical manipulation of the ascending aorta that occasionally leads to type A aortic dissection (AAD). METHODS AND RESULTS: One hundred three patients with surgical repair for AAD following nonaortic cardiac surgery were identified. With the use of logistic regression modeling, coronary artery bypass surgery (CABG), either isolated or combined with another procedure in the initial operation, was associated with significantly higher operative mortality in comparison with patients with non-CABG procedures at the time of AAD repair both for all patients (odds ratio, 2.90; 95% confidence interval, 1.09-7.72; P=0.033) and for patients with acute and chronic AAD≥30 days after the initial operation (odds ratio, 3.62; 95% confidence interval, 1.13-11.54; P=0.03). In patients who developed AAD late after the initial operation, operative mortality was highest in patients without preoperative coronary angiography and appropriate management of their native coronary artery disease and graft disease (odds ratio, 5.36; 95% confidence interval, 1.68-17.0; P=0.002). Nearly all the intimal dissection tears were located at sites of previous surgical trauma. Most of the ascending aortas that had dissected initially had a diameter≥40 mm with histological evidence of medial degeneration in resected tissue samples. CONCLUSIONS: In patients who have undergone previous cardiac surgery, preexisting aortic wall pathology contributes to AAD with typical intimal damage at sites of mechanical trauma. The operative mortality was the highest in patients with previous CABG in comparison with patients with non-CABG procedures. Preoperative coronary angiography and operative management of native coronary and graft disease were significantly associated with outcome in patients with previous CABG.

Interactions between vascular wall and perivascular adipose tissue reveal novel roles for adiponectin in the regulation of endothelial nitric oxide synthase function in human vessels.

BACKGROUND: Adiponectin is an adipokine with potentially important roles in human cardiovascular disease states. We studied the role of adiponectin in the cross-talk between adipose tissue and vascular redox state in patients with atherosclerosis. METHODS AND RESULTS: The study included 677 patients undergoing coronary artery bypass graft surgery. Endothelial function was evaluated by flow-mediated dilation of the brachial artery in vivo and by vasomotor studies in saphenous vein segments ex vivo. Vascular superoxide (O2(-)) and endothelial nitric oxide synthase (eNOS) uncoupling were quantified in saphenous vein and internal mammary artery segments. Local adiponectin gene expression and ex vivo release were quantified in perivascular (saphenous vein and internal mammary artery) subcutaneous and mesothoracic adipose tissue from 248 patients. Circulating adiponectin was independently associated with nitric oxide bioavailability and O2(-) production/eNOS uncoupling in both arteries and veins. These findings were supported by a similar association between functional polymorphisms in the adiponectin gene and vascular redox state. In contrast, local adiponectin gene expression/release in perivascular adipose tissue was positively correlated with O2(-) and eNOS uncoupling in the underlying vessels. In ex vivo experiments with human saphenous veins and internal mammary arteries, adiponectin induced Akt-mediated eNOS phosphorylation and increased tetrahydrobiopterin bioavailability, improving eNOS coupling. In ex vivo experiments with human saphenous veins/internal mammary arteries and adipose tissue, we demonstrated that peroxidation products produced in the vascular wall (ie, 4-hydroxynonenal) upregulate adiponectin gene expression in perivascular adipose tissue via a peroxisome proliferator-activated receptor-γ-dependent mechanism. CONCLUSIONS: We demonstrate for the first time that adiponectin improves the redox state in human vessels by restoring eNOS coupling, and we identify a novel role of vascular oxidative stress in the regulation of adiponectin expression in human perivascular adipose tissue.

Myocardial perfusion and oxygenation are impaired during stress in severe aortic stenosis and correlate with impaired energetics and subclinical left ventricular dysfunction.

BACKGROUND: Left ventricular (LV) hypertrophy in aortic stenosis (AS) is characterized by reduced myocardial perfusion reserve due to coronary microvascular dysfunction. However, whether this hypoperfusion leads to tissue deoxygenation is unknown. We aimed to assess myocardial oxygenation in severe AS without obstructive coronary artery disease, and to investigate its association with myocardial energetics and function. METHODS: Twenty-eight patients with isolated severe AS and 15 controls underwent cardiovascular magnetic resonance (CMR) for assessment of perfusion (myocardial perfusion reserve index-MPRI) and oxygenation (blood-oxygen level dependent-BOLD signal intensity-SI change) during adenosine stress. LV circumferential strain and phosphocreatine/adenosine triphosphate (PCr/ATP) ratios were assessed using tagging CMR and 31P MR spectroscopy, respectively. RESULTS: AS patients had reduced MPRI (1.1 ± 0.3 vs. controls 1.7 ± 0.3, p < 0.001) and BOLD SI change during stress (5.1 ± 8.9% vs. controls 18.2 ± 10.1%, p = 0.001), as well as reduced PCr/ATP (1.45 ± 0.21 vs. 2.00 ± 0.25, p < 0.001) and LV strain (-16.4 ± 2.7% vs. controls -21.3 ± 1.9%, p < 0.001). Both perfusion reserve and oxygenation showed positive correlations with energetics and LV strain. Furthermore, impaired energetics correlated with reduced strain. Eight months post aortic valve replacement (AVR) (n = 14), perfusion (MPRI 1.6 ± 0.5), oxygenation (BOLD SI change 15.6 ± 7.0%), energetics (PCr/ATP 1.86 ± 0.48) and circumferential strain (-19.4 ± 2.5%) improved significantly. CONCLUSIONS: Severe AS is characterized by impaired perfusion reserve and oxygenation which are related to the degree of derangement in energetics and associated LV dysfunction. These changes are reversible on relief of pressure overload and hypertrophy regression. Strategies aimed at improving oxygen demand-supply balance to preserve myocardial energetics and LV function are promising future therapies.

Study protocol for a cross-sectional online survey investigating patient preferences and experiences of waiting for elective cardiac surgery.

INTRODUCTION: Being on a waiting list for elective (planned) cardiac surgery can be physically and psychologically challenging for patients. Research suggests that stress associated with waiting for surgery is dependent on different individual and contextual factors. However, most data on patients' experiences of waiting for surgery and preferences for waiting list management derives from non-cardiac clinical populations. The aim of the current study is to explore patients' experiences of being on a waiting list for elective cardiac surgery, and their views on how the waiting experience could be improved in the future. This work will inform the patient management strategy during the waiting period for surgery across the four major hospitals in London directly involved in this study, and potentially beyond by transferring learning to other services. METHODS AND ANALYSIS: This is a mixed-methods study that will collect quantitative and qualitative data using a cross-sectional online survey. Patients who are on waiting lists for elective surgery across four major cardiac surgery departments in London hospitals, and are at least 18 years old, will be invited by their healthcare team via text message or letter to complete the survey. The target sample size of non-randomly selected participants will be 268. Bivariable and multivariable regression models will be used to assess associations between survey items measuring the impact of the cardiac condition on specific life domains (eg, daily activities, social and family relationships, hobbies, sexual life), anxiety and depression symptoms as measured by the Patient Health Questionnaire-4 and survey items evaluating experiences of health services. Data on experience and preferences for improvements to the waiting experience will be analysed with qualitative content analysis using an inductive approach. ETHICS AND DISSEMINATION: This study was reviewed and granted ethical approval by the East of England-East Cambridge Research Ethics Committee. Findings from this study will be disseminated through peer-reviewed journals, a research website and social media and with an online event engaging patients, members of the public, healthcare professionals and other relevant stakeholders. TRIAL REGISTRATION NUMB: NCT05996640.

High levels of circulating epinephrine trigger apical cardiodepression in a ß2-adrenergic receptor/Gi-dependent manner: a new model of Takotsubo cardiomyopathy.

BACKGROUND: Takotsubo cardiomyopathy is an acute heart failure syndrome characterized by myocardial hypocontractility from the mid left ventricle to the apex. It is precipitated by extreme stress and can be triggered by intravenous catecholamine administration, particularly epinephrine. Despite its grave presentation, Takotsubo cardiomyopathy is rapidly reversible, with generally good prognosis. We hypothesized that this represents switching of epinephrine signaling through the pleiotropic ß(2)-adrenergic receptor (ß(2)AR) from canonical stimulatory G-protein-activated cardiostimulant to inhibitory G-protein-activated cardiodepressant pathways. METHODS AND RESULTS: We describe an in vivo rat model in which a high intravenous epinephrine, but not norepinephrine, bolus produces the characteristic reversible apical depression of myocardial contraction coupled with basal hypercontractility. The effect is prevented via G(i) inactivation by pertussis toxin pretreatment. ß(2)AR number and functional responses were greater in isolated apical cardiomyocytes than in basal cardiomyocytes, which confirmed the higher apical sensitivity and response to circulating epinephrine. In vitro studies demonstrated high-dose epinephrine can induce direct cardiomyocyte cardiodepression and cardioprotection in a ß(2)AR-Gi-dependent manner. Preventing epinephrine-G(i) effects increased mortality in the Takotsubo model, whereas ß-blockers that activate ß(2)AR-G(i) exacerbated the epinephrine-dependent negative inotropic effects without further deaths. In contrast, levosimendan rescued the acute cardiac dysfunction without increased mortality. CONCLUSIONS: We suggest that biased agonism of epinephrine for ß(2)AR-G(s) at low concentrations and for G(i) at high concentrations underpins the acute apical cardiodepression observed in Takotsubo cardiomyopathy, with an apical-basal gradient in ß(2)ARs explaining the differential regional responses. We suggest this epinephrine-specific ß(2)AR-G(i) signaling may have evolved as a cardioprotective strategy to limit catecholamine-induced myocardial toxicity during acute stress.

Giant proximal left anterior descending aneurysm causing multi-vessel myocardial ischaemia: the pressure is on-a case report.

Background: Giant coronary artery aneurysms are a rare cause of myocardial ischaemia. Due to the rarity and variety of presentation of these cases, no standardized investigation or treatment has been established for management. We report a case study of a giant proximal left anterior descending (LAD) coronary aneurysm causing myocardial ischaemia due to the pressure effect from the weight of the aneurysm as well as from a change in rheology from a 'steal effect' on both the LAD and left circumflex (LCx) arteries. Case summary: A 55-year-old patient presents initially with a history of angina. Initial investigation with computed tomography (CT) was suboptimal, requiring invasive diagnostic angiography, which detects a giant proximal LAD aneurysm. Subsequent investigations, with CT-fractional flow reserve (FFR) and stress echocardiography (ECHO), correlated to identify multi-vessel ischaemia resulting from the aneurysm. The patient was managed with multi-disciplinary team-led surgical resection and triple coronary artery bypass grafts with good results. Discussion: This case highlights the complexity of coronary anomalies and importance of additional functional three-dimensional imaging on top of the static computational tomography coronary angiography analysis. Together, these two complimentary investigations qualitatively enabled the assessment of anomaly with surrounding structures such that the possibility of a mass effect on the LCx artery results in a positive stress test. Furthermore, this is a novel use of CT-FFR for coronary anomalies and it demonstrated good correlation of LAD territory ischaemia between CT-FFR and the stress ECHO.

Recurrent Nonbacterial Thrombotic Endocarditis and Primary Antiphospholipid Antibody Syndrome.

In 2015, a 37-year-old man was referred for evaluation of hypertension and was found to have a mobile structure on the posterior mitral valve leaflet on echocardiography. Laboratory investigations yielded a diagnosis of primary antiphospholipid antibody syndrome (APLS). He underwent excision of the lesion and mitral valve repair. Histology confirmed the diagnosis of nonbacterial thrombotic endocarditis (NBTE). The patient was anticoagulated with warfarin up until 2018, which was substituted for rivaroxaban because of an erratic international normalised ratio. Serial echocardiography up to 2020 was unremarkable. In 2021, he presented with breathlessness and peripheral oedema. Echocardiography demonstrated large vegetation on both mitral valve leaflets. At the operation, vegetations were also evident on the left and noncoronary cusps of the aortic valve and he underwent mechanical aortic and mitral valve replacement. Histology confirmed NBTE. The case is unusual and highlights recurrent NBTE requiring re-do valve surgery.