Recent Submissions

  • Surveillance for moderate-sized thoracic aortic aneurysms: Equality is the goal

    Acharya, Metesh; Mariscalco, Giovanni (2022-04)
    Comprehensive clinical and imaging-based surveillance represents a fundamental aspect in the management of thoracic aortic aneurysms (TAAs), affording the opportunity to identify intermediate-sized TAAs before the onset of worrying symptoms or devastating acute aortic dissection/rupture. Currently, size-based indices are favored as the major determinants driving patient selection for surgery, as supported by aortic guidelines, although it is recognized that smaller subthreshold TAAs may still confer substantial risks. Prophylactic aortic surgery can be offered within set timeframes at dedicated aortic centers with excellent outcomes, to mitigate the threat of acute aortic complications associated with a repeatedly deferred intervention. In this commentary, we discuss a recent article from the Journal of Cardiac Surgery that highlights important socioeconomic disparities in TAA surveillance and follow-up.
  • Neuroprotective strategies in acute aortic dissection: an analysis of the UK National Adult Cardiac Surgical Audit

    Mariscalco, Giovanni (2021-12)
    Objectives: The risk of brain injury following surgery for type A aortic dissection (TAAD) remains substantial and no consensus has still been reached on which neuroprotective technique should be preferred. We aimed to investigate the association between neuroprotective strategies and clinical outcomes following TAAD repair. Methods: Using the UK National Adult Cardiac Surgical Audit, we identified 1929 patients undergoing surgery for TAAD (2011-2018). Deep hypothermic circulatory arrest (DHCA) only, unilateral (uACP), bilateral antegrade cerebral perfusion (bACP) and retrograde cerebral perfusion were used in 830, 117, 760 and 222 patients, respectively. The primary end point was a composite of death and/or cerebrovascular accident (CVA). Generalized linear mixed model was used to adjust the effect of neuroprotective strategies for other confounders. Results: The use of bACP was associated with longer circulatory arrest (CA) compared to other strategies. There was a trend towards lower incidence of death and/or CVA using uACP only for shorter CA. In particular, primary end point rate was 27.7% overall and 26.5%, 12.5%, 28.0% and 22.9% for CA <30 min and 28.6%, 30.4%, 33.3% and 33.0% for CA ≥30 min with DHCA only, uACP, bACP and retrograde cerebral perfusion, respectively. The use of DHCA only was associated with five-fold [odds ratio (OR) 5.35, 95% confidence interval (CI) 1.36-21.02] and two-fold (OR 1.77, 95% CI 1.01-3.09) increased risk of death and/or CVA compared to uACP and bACP, respectively, but the effect of uACP was significantly associated with CA duration (hazard ratio 0.97, 95% CI 0.94-0.99; P = 0.04). Conclusions: In TAAD repair, the use of uACP and bACP was associated with a lower adjusted risk of death and/or CVA when compared to DHCA. uACP can offer some advantage but only for a shorter CA duration.
  • Prevalence and disease spectrum of extracoronary arterial abnormalities in spontaneous coronary artery dissection

    Adair, William; Chan, Nathan; Kotecha, Deevia; Kandiyil, Neghal; Parke, Kelly; Premawardhana, Diluka; Sajitha, Averachan; Wormleighton, Joanne; Samani, Nilesh; McCann, Gerry; et al. (2022)
    Importance: Spontaneous coronary artery dissection (SCAD) has been associated with fibromuscular dysplasia (FMD) and other extracoronary arterial abnormalities. However, the prevalence, severity, and clinical relevance of these abnormalities remain unclear. Objective: To assess the prevalence and spectrum of FMD and other extracoronary arterial abnormalities in patients with SCAD vs controls. Design, setting, and participants: This case series included 173 patients with angiographically confirmed SCAD enrolled between January 1, 2015, and December 31, 2019. Imaging of extracoronary arterial beds was performed by magnetic resonance angiography (MRA). Forty-one healthy individuals were recruited to serve as controls for blinded interpretation of MRA findings. Patients were recruited from the UK national SCAD registry, which enrolls throughout the UK by referral from the primary care physician or patient self-referral through an online portal. Participants attended the national SCAD referral center for assessment and MRA. Exposures: Both patients with SCAD and healthy controls underwent head-to-pelvis MRA (median time between SCAD event and MRA, 1 [IQR, 1-3] year). Main outcome and measures: The diagnosis of FMD, arterial dissections, and aneurysms was established according to the International FMD Consensus. Arterial tortuosity was assessed both qualitatively (presence or absence of an S curve) and quantitatively (number of curves ≥45%; tortuosity index). Results: Of the 173 patients with SCAD, 167 were women (96.5%); mean (SD) age at diagnosis was 44.5 (7.9) years. The prevalence of FMD was 31.8% (55 patients); 16 patients (29.1% of patients with FMD) had involvement of multiple vascular beds. Thirteen patients (7.5%) had extracoronary aneurysms and 3 patients (1.7%) had dissections. The prevalence and degree of arterial tortuosity were similar in patients and controls. In 43 patients imaged with both computed tomographic angiography and MRA, the identification of clinically significant remote arteriopathies was similar. Over a median 5-year follow-up, there were 2 noncardiovascular-associated deaths and 35 recurrent myocardial infarctions, but there were no primary extracoronary vascular events. Conclusions and relevance: In this case series with blinded analysis of patients with SCAD, severe multivessel FMD, aneurysms, and dissections were infrequent. The findings of this study suggest that, although brain-to-pelvis imaging allows detection of remote arteriopathies that may require follow-up, extracoronary vascular events appear to be rare.
  • Outcomes following PCI in CABG candidates during the COVID-19 pandemic: The prospective multicentre UK-ReVasc registry

    Kite, Thomas; Ladwiniec, Andrew; Siddique, Laraib; Gershlick, Anthony (2022)
    Objectives: To describe outcomes following percutaneous coronary intervention (PCI) in patients who would usually have undergone coronary artery bypass grafting (CABG). Background: In the United Kingdom, cardiac surgery for coronary artery disease (CAD) was dramatically reduced during the first wave of the COVID-19 pandemic. Many patients with "surgical disease" instead underwent PCI. Methods: Between 1 March 2020 and 31 July 2020, 215 patients with recognized "surgical" CAD who underwent PCI were enrolled in the prospective UK-ReVasc Registry (ReVR). 30-day major cardiovascular event outcomes were collected. Findings in ReVR patients were directly compared to reference PCI and isolated CABG pre-COVID-19 data from British Cardiovascular Intervention Society (BCIS) and National Cardiac Audit Programme (NCAP) databases. Results: ReVR patients had higher incidence of diabetes (34.4% vs 26.4%, P = .008), multi-vessel disease with left main stem disease (51.4% vs 3.0%, P < .001) and left anterior descending artery involvement (94.8% vs 67.2%, P < .001) compared to BCIS data. SYNTAX Score in ReVR was high (mean 28.0). Increased use of transradial access (93.3% vs 88.6%, P = .03), intracoronary imaging (43.6% vs 14.4%, P < .001) and calcium modification (23.6% vs 3.5%, P < .001) was observed. No difference in in-hospital mortality was demonstrated compared to PCI and CABG data (ReVR 1.4% vs BCIS 0.7%, P = .19; vs NCAP 1.0%, P = .48). Inpatient stay was half compared to CABG (3.0 vs 6.0 days). Low-event rates in ReVR were maintained to 30-day follow-up. Conclusions: PCI undertaken using contemporary techniques produces excellent short-term results in patients who would be otherwise CABG candidates. Longer-term follow-up is essential to determine whether these outcomes are maintained over time.
  • Role of hypothermia in adult cardiac surgery patients: a systematic review and meta-analysis

    Abbasciano, Riccardo; Koulouroudias, Marinos; Chad, Thomas; Murphy, Gavin (2022)
    Objective: To review studies that assessed systemic hypothermia as an organ protection strategy in adults undergoing cardiac surgery with cardiopulmonary bypass. Design: A systematic review and meta-analysis. Setting and participants: Randomized controlled trials, irrespective of blinding, language, publication status, and date of publication, were identified by searching the Cochrane Central register of Controlled Trials, MEDLINE, and Embase until November 2020. Risk of bias assessment was performed according to Cochrane methodology. Treatment effects were expressed as risk ratios and 95% confidence intervals. Heterogeneity was expressed as I2. Interventions: Systemic hypothermia. Measurements and main results: Forty-eight trials enrolling 6,690 patients were included in the analysis. Methodologic quality of the studies included was low, mostly due to insufficient allocation concealment or blinding. Random-effects meta-analysis did not resolve uncertainty as to the risks and benefits for hypothermia versus normothermia for key primary and secondary outcomes, including mortality (1.21, 0.94 to 1.56, I2 = 0%) and brain injury (0.87, 0.67 to 1.14, I2 = 0%). Sensitivity analyses restricted to trials at low risk of important bias demonstrated higher mortality with hypothermia (1.70, 1.05 to 2.75, I2 = 0%), with little or no treatment effect on brain injury (1.01, 0.69 to 1.49, I2 = 0%). There was no interaction between cardioplegia temperature and the effects of cardiopulmonary bypass temperature on outcomes. There was insufficient evidence to assess the effects of hypothermia in noncoronary artery bypass graft surgery. Conclusion: The existing evidence for an organ-protective effect of hypothermia in adult cardiac surgery is of low quality and inconsistent.
  • Acute shear stress and vein graft disease

    McQueen, Liam; Ladak, Shameem; Zakkar, Mustafa (2022)
    The long saphenous vein is commonly used in cardiac surgery to bypass occluded coronary arteries. Its use is complicated by late stenosis and occlusion due to the development of intimal hyperplasia. It is accepted that intimal hyperplasia is a multifactorial inflammatory process that starts immediately after surgery. The role of acute changes in haemodynamic conditions when the vein is implanted into arterial circulation, especially shear stress, is not fully appreciated. This review provides an overview of intimal hyperplasia and the effect of acute shear stress changes on the activation of pro-inflammatory mediators.
  • The role of the ADVanced Organ Support (ADVOS) system in critically ill patients with multiple organ failure

    Acharya, Metesh (2022)
    Background: Multi-organ failure characterized by acute kidney injury, liver dysfunction, and respiratory failure is a complex condition associated with high mortality, for which multiple individual support devices may be simultaneously required. This review aims to appraise the current evidence for the ADVanced Organ Support (ADVOS) system, a novel device integrating liver, lung, and kidney support with blood detoxification. Methods: We performed a literature review of the PubMed database to identify human and animal studies evaluating the ADVOS system. Results: In porcine models of acute liver injury and small clinical studies in humans, ADVOS significantly enhanced the elimination of water-soluble and protein-bound toxins and metabolites, including creatinine, ammonia, blood urea nitrogen, and lactate. Cardiovascular parameters (mean arterial pressure, cerebral perfusion pressure, and cardiac index) and renal function were improved. ADVOS clears carbon dioxide (CO2 ) effectively with rapid correction of pH abnormalities, achieving normalization of CO2 , and bicarbonate levels. In patients with COVID-19 infection, ADVOS enables rapid correction of acid-base disturbance and respiratory acidosis. ADVOS therapy reduces mortality in multi-organ failure and has been shown to be safe with minimal adverse events. Conclusions: From the small observational studies analyzed, ADVOS demonstrates excellent detoxification of water-soluble and protein-bound substances. In particular, ADVOS permits the correction of metabolic and respiratory acidosis through the fluid-based direct removal of acid and CO2 . ADVOS is associated with significant improvements in hemodynamic and biochemical parameters, a trend toward improved survival in multi-organ failure, and is well-tolerated. Larger randomized trials are now necessary to further validate these encouraging results.
  • Gene and metabolite expression dependence on body mass index in human myocardium

    Roman, Marius; Zakkar, Mustafa; Joel-David, Lathishia; Kumar, Tracy; Murphy, Gavin (2022)
    We hypothesized that body mass index (BMI) dependent changes in myocardial gene expression and energy-related metabolites underlie the biphasic association between BMI and mortality (the obesity paradox) in cardiac surgery. We performed transcriptome profiling and measured a panel of 144 metabolites in 53 and 55, respectively, myocardial biopsies from a cohort of sixty-six adult patients undergoing coronary artery bypass grafting (registration: NCT02908009). The initial analysis identified 239 transcripts with biphasic BMI dependence. 120 displayed u-shape and 119 n-shape expression patterns. The identified local minima or maxima peaked at BMI 28-29. Based on these results and to best fit the WHO classification, we grouped the patients into three groups: BMI < 25, 25 ≤ BMI ≤ 32, and BMI > 32. The analysis indicated that protein translation-related pathways were downregulated in 25 ≤ BMI ≤ 32 compared with BMI < 25 patients. Muscle contraction transcripts were upregulated in 25 ≤ BMI ≤ 32 patients, and cholesterol synthesis and innate immunity transcripts were upregulated in the BMI > 32 group. Transcripts involved in translation, muscle contraction and lipid metabolism also formed distinct correlation networks with biphasic dependence on BMI. Metabolite analysis identified acylcarnitines and ribose-5-phosphate increasing in the BMI > 32 group and α-ketoglutarate increasing in the BMI < 25 group. Molecular differences in the myocardium mirror the biphasic relationship between BMI and mortality.
  • Coronary artery bypass grafting in patients with high risk of bleeding

    Mariscalco, Giovanni (2022)
    Background: Postoperative bleeding after cardiac surgery is associated with increased morbidity and mortality. We tested the hypothesis that patients with a preoperatively estimated high risk of severe perioperative bleeding may have impaired early outcome after on-pump versus off-pump coronary artery bypass grafting (CABG). Method: Data from 7,352 consecutive patients who underwent isolated CABG from January 2015 to May 2017 were included in the multicentre European Coronary Artery Bypass Grafting registry. The postoperative bleeding risk was estimated using the WILL-BLEED risk score. Of all included patients, 3,548 had an increased risk of severe perioperative bleeding (defined as a WILL-BLEED score ≥4) and were the subjects of this analysis. We compared the early outcomes between patients who underwent on-pump or off-pump CABG using a multivariate mixed model for risk-adjusted analysis. Results: Off-pump surgery was performed in 721 patients (20.3%). On-pump patients received more packed red blood cell units (on-pump: 1.41 [95% confidence interval {CI} 0.99-1.86]; off-pump: 0.86 [95% CI 0.64-1.08]; p<0.001), had a longer stay in the intensive care unit (on-pump: 4.4 [95% CI 3.6-8.1] days; off-pump: 3.2 [95% CI 2.0-4.4] days; p=0.049), and a higher rate of postoperative atrial fibrillation (on-pump: 46.5% [95% CI 34.9-58.1]; off-pump: 31.3% [95% CI 21.7-40.9]; p=0.025). Furthermore, on-pump patients showed a trend towards a higher rate of postoperative stroke (on-pump: 2.4% [95% CI 0.9-4.1]; off-pump: 1.1 [95% CI 0.2-2.7]; p=0.094). Conclusion: Our data suggest that in patients with an increased risk of bleeding, the use of cardiopulmonary bypass is associated with higher morbidity. These patients may benefit from off-pump surgery if complete revascularisation can be ensured.
  • Artificial intelligence for stepwise diagnosis and monitoring of COVID-19

    Ang, Keng-Leong (2022)
    Background: Main challenges for COVID-19 include the lack of a rapid diagnostic test, a suitable tool to monitor and predict a patient's clinical course and an efficient way for data sharing among multicenters. We thus developed a novel artificial intelligence system based on deep learning (DL) and federated learning (FL) for the diagnosis, monitoring, and prediction of a patient's clinical course. Methods: CT imaging derived from 6 different multicenter cohorts were used for stepwise diagnostic algorithm to diagnose COVID-19, with or without clinical data. Patients with more than 3 consecutive CT images were trained for the monitoring algorithm. FL has been applied for decentralized refinement of independently built DL models. Results: A total of 1,552,988 CT slices from 4804 patients were used. The model can diagnose COVID-19 based on CT alone with the AUC being 0.98 (95% CI 0.97-0.99), and outperforms the radiologist's assessment. We have also successfully tested the incorporation of the DL diagnostic model with the FL framework. Its auto-segmentation analyses co-related well with those by radiologists and achieved a high Dice's coefficient of 0.77. It can produce a predictive curve of a patient's clinical course if serial CT assessments are available. Interpretation: The system has high consistency in diagnosing COVID-19 based on CT, with or without clinical data. Alternatively, it can be implemented on a FL platform, which would potentially encourage the data sharing in the future. It also can produce an objective predictive curve of a patient's clinical course for visualization. Key points: • CoviDet could diagnose COVID-19 based on chest CT with high consistency; this outperformed the radiologist's assessment. Its auto-segmentation analyses co-related well with those by radiologists and could potentially monitor and predict a patient's clinical course if serial CT assessments are available. It can be integrated into the federated learning framework. • CoviDet can be used as an adjunct to aid clinicians with the CT diagnosis of COVID-19 and can potentially be used for disease monitoring; federated learning can potentially open opportunities for global collaboration.
  • Determinants of outcomes following surgery for type A acute aortic dissection: the UK National Adult Cardiac Surgical Audit

    Mariscalco, Giovanni (2021)
    Aims: Operability of type A acute aortic dissections (TAAAD) is currently based on non-standardized decision-making process, and it lacks a disease-specific risk evaluation model that can predict mortality. We investigated patient, intraoperative data, surgeon, and centre-related variables for patients who underwent TAAAD in the UK. Methods and results: We identified 4203 patients undergoing TAAAD surgery in the UK (2009-18), who were enrolled into the UK National Adult Cardiac Surgical Audit dataset. The primary outcome was operative mortality. A multivariable logistic regression analysis was performed with fast backward elimination of variables and the bootstrap-based optimism-correction was adopted to assess model performance. Variation related to hospital or surgeon effects were quantified by a generalized mixed linear model and risk-adjusted funnel plots by displaying the individual standardized mortality ratio against expected deaths. Final variables retained in the model were: age [odds ratio (OR) 1.02, 95% confidence interval (CI) 1.02-1.03; P < 0.001]; malperfusion (OR 1.79, 95% CI 1.51-2.12; P < 0.001); left ventricular ejection fraction (moderate: OR 1.40, 95% CI 1.14-1.71; P = 0.001; poor: OR 2.83, 95% CI 1.90-4.21; P < 0.001); previous cardiac surgery (OR 2.29, 95% CI 1.71-3.07; P < 0.001); preoperative mechanical ventilation (OR 2.76, 95% CI 2.00-3.80; P < 0.001); preoperative resuscitation (OR 3.36, 95% CI 1.14-9.87; P = 0.028); and concomitant coronary artery bypass grafting (OR 2.29, 95% CI 1.86-2.83; P < 0.001). We found a significant inverse relationship between surgeons but not centre annual volume with outcomes. Conclusions: Patient characteristics, intraoperative factors, cardiac centre, and high-volume surgeons are strong determinants of outcomes following TAAAD surgery. These findings may help refining clinical decision-making, supporting patient counselling and be used by policy makers for quality assurance and service provision improvement.