Alexander Liu

Dr. Alexander Liu

orcid

Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 May 2025 in Biomedicines
Verified
Journal Article
Open access
PDF file
SMSamuel Malomo
Samuel Malomo
TOThomas Oswald
Thomas Oswald
TAThomas Alway
Thomas Alway
SHStanislav Hadjivassilev
Stanislav Hadjivassilev
SCSteve Coombs
Steve Coombs
ALAlexander Liu
Alexander Liu
Background: Sepsis survivors are at risk of developing myocardial infarction and heart failure. It remains unclear whether coronary artery disease (CAD) is a major contributor to the development of these complications. This study sought to characterize the burden and distribution of significant CAD in sepsis survivors. Methods: Sepsis survivors who underwent computed tomography coronary angiography (CTCA) or invasive coronary angiography (ICA) in a UK tertiary cardiac center for suspected ischemic heart disease were retrospectively studied. Results: Of the 30 sepsis survivors (age 57 ± 12 years; 50% males), 21 patients underwent CTCA and 9 patients underwent ICA a median 39 days [IQR 12–152] from the sepsis episode. Eight patients (~27%) had angiographically significant CAD (n = 6 severe [>70%] stenosis; n = 2 moderate [50–70%] stenosis). The CT coronary calcium score was higher in patients with significant CAD compared to patients without significant CAD (638 [368–1015] vs. 4 [1–72]; p < 0.001). Of the 8 patients with significant CAD, 3 patients had LV systolic dysfunction (38%) on echocardiography and 8/21 (38%) patients without significant CAD had LV systolic dysfunction (p = 1.00). Long-term adverse complications (all-cause mortality and/or heart failure hospitalization) occurred 3/8 (38%) patients with significant CAD and 4/22 (18%) patients without significant CAD (p = 0.345). Conclusions: A minority of sepsis survivors have significant CAD. The presence of significant CAD cannot fully explain the occurrence of post-sepsis LV systolic dysfunction and adverse outcomes. The ischemic and non-ischemic mechanisms underlying post-sepsis cardiovascular disease require further investigation.

13 January 2024 in Biomedicines
Verified
Journal Article
Open access
PDF file
ALAlexander Liu
Alexander Liu
LPLaura C. Price
Laura C. Price
RSRakesh Sharma
Rakesh Sharma
AWAthol U Wells
Athol U Wells
VKVasileios Kouranos
Vasileios Kouranos
In patients with sarcoidosis, the development of pulmonary hypertension is associated with significant morbidity and mortality. The global prevalence of sarcoidosis-associated pulmonary hypertension (SAPH) reportedly ranges between 2.9% and 20% of sarcoidosis patients. Multiple factors may contribute to the development of SAPH, including advanced parenchymal lung disease, severe systolic and/or diastolic left ventricular dysfunction, veno-occlusive or thromboembolic disease, as well as extrinsic factors such as pulmonary vascular compression from enlarged lymph nodes, anemia, and liver disease. Early diagnosis of SAPH is important but rarely achieved primarily due to insufficiently accurate screening strategies, which rely entirely on non-invasive tests and clinical assessment. The definitive diagnosis of SAPH requires right heart catheterization (RHC), with transthoracic echocardiography as the recommended gatekeeper to RHC according to current guidelines. A 6-min walk test (6MWT) had the greatest prognostic value in SAPH patients based on recent registry outcomes, while advanced lung disease determined using a reduced DLCO (<35% predicted) was associated with reduced transplant-free survival in pre-capillary SAPH. Clinical management involves the identification and treatment of the underlying mechanism. Pulmonary vasodilators are useful in several scenarios, especially when a pulmonary vascular phenotype predominates. End-stage SAPH may warrant consideration for lung transplantation, which remains a high-risk option. Multi-centered randomized controlled trials are required to develop existing therapies further and improve the prognosis of SAPH patients.

14 April 2025 in Diagnostics
Verified
Journal Article
Open access
PDF file
SMSamuel Malomo
Samuel Malomo
TOThomas Oswald
Thomas Oswald
ESEdward Edward Stephenson
Edward Edward Stephenson
AYAnthony Yip
Anthony Yip
TAThomas Alway
Thomas Alway
ALAlexander Liu
Alexander Liu
Background: Post-sepsis cardiomyopathy is associated with an increased risk of adverse cardiovascular outcomes. It remains poorly understood, which limits therapeutic development. This study characterised post-sepsis cardiomyopathy using cardiovascular magnetic resonance (CMR) imaging. Methods: Patients admitted with acute sepsis and suspected cardiac injury or heart failure who subsequently (47 days [IQR: 22–122]) underwent CMR at a UK tertiary cardiac centre were included. Age- and gender-matched controls (n = 16) were also included. Subjects underwent CMR at 1.5 Tesla with cines, native T1- and T2-mapping, and late gadolinium enhancement (LGE) imaging. Results: Of the 22 post-sepsis patients (age 50 ± 13 years; 64% males), 13 patients (59%) had left ventricular (LV) dilatation. Patients had significantly elevated left ventricular (LV) end-diastolic and end-systolic volume indices compared to controls (p = 0.011 and p = 0.013, respectively). Eleven patients (50%) had LV systolic dysfunction (ejection fraction < 50%), most of whom (8/11) had non-ischaemic patterns of LGE (n = 7 mid-wall; n = 1 mid-wall/patchy). In the eleven patients with preserved LV systolic function (ejection fraction ≥ 50%), three patients (27%) had significant LGE (n = 1 mid-wall; n = 1 subepicardial/mid-wall; n = 1 patchy). Compared to controls, patients had elevated septal native myocardial T1 values (p < 0.001) but similar septal native myocardial T2 values (p = 0.090), suggesting the presence of myocardial fibrosis without significant oedema. Conclusions: Post-sepsis cardiomyopathy is characterised by LV dilatation, systolic dysfunction, and myocardial fibrosis in a non-ischaemic distribution. Significant myocardial oedema is not prominent several weeks post-recovery. Further work is needed to test these findings on a multi-centre basis and to develop novel therapies for post-sepsis cardiomyopathy.

27 February 2025 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
SFSami Fouda
Sami Fouda
RGRebecca Godfrey
Rebecca Godfrey
CPChristopher Pavitt
Christopher Pavitt
TAThomas Alway
Thomas Alway
SCSteve Coombs
Steve Coombs
ALAlexander Liu
Alexander Liu
Cardiac sarcoidosis (CS) and inherited cardiomyopathies (inherited CM) are associated with advanced heart failure, cardiac conduction defects, ventricular arrhythmias and sudden cardiac death. Both conditions can have similar clinical presentations. Differentiating between the two disease cohorts is important in delivering specific management to patients, such as immunosuppressive therapy for CS patients and genetic screening for inherited CM. In this review, we examined the existing evidence on the overlap between CS and common inherited CM, such as hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, restrictive cardiomyopathy and dilated cardiomyopathy. In patients where both CS and inherited CM were implicated, CS tended to be diagnosed much later, often when patients presented with complications warranting a workup or cardiac histological confirmation. CS can masquerade as an inherited CM, leading to delays in the instigation of CS therapy. Confirmed dual pathology overlap between inherited CM and CS is rarer. Advanced cardiac imaging, such as cardiovascular magnetic resonance, plays an important role in the clinical workup of both CS and inherited CM. However, findings on cardiac imaging alone often cannot differentiate between the two conditions. Definitive differentiation between CS and inherited CM requires both clinical experience and, at times, a myocardial biopsy.

13 December 2024 in Hearts
Verified
Journal Article
Open access
PDF file
SFSami Fouda
Sami Fouda
RHRobert Hammond
Robert Hammond
PDPeter Donnelly
Peter Donnelly
ACAnthony Coates
Anthony Coates
ALAlexander Liu
Alexander Liu
Coronavirus disease 19 (COVID-19) is responsible for one of the worst pandemics in human history. The causative virus, the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), can invade host cells in multiple organs by binding the angiotensin-converting enzyme (ACE) II expressed on the cell surface. Once inside the host cell, viral replication takes place, leading to cellular disruption and the release of signal molecules that are recognised by the innate immune system. Innate immunity activation leads to the release of proinflammatory cytokines and primes the adaptive immune system. The proinflammatory environment defends against further viral entry and replication. SARS-CoV-2 infection is thought to lead to myocardial injury through several mechanisms. Firstly, direct viral-mediated cellular invasion of cardiomyocytes has been shown in in vitro and histological studies, which is related to cellular injury. Secondly, the proinflammatory state during COVID-19 can lead to myocardial injury and the release of protein remnants of the cardiac contractile machinery. Thirdly, the hypercoagulable state of COVID-19 is associated with thromboembolism of coronary arteries and/or other vascular systems. COVID-19 patients can also develop heart failure; however, the underlying mechanism is much less well-characterised than for myocardial injury. Several questions remain regarding COVID-19-related heart failure, including its potential reversibility, the role of anti-viral medications in its prevention, and the mechanisms underlying heart failure pathogenesis in long COVID-19. Further work is required to improve our understanding of the mechanism of cardiac sequelae in COVID-19, which may enable us to target SARS-CoV-2 and protect patients against longer-lasting cardiovascular complications.

Verified
Journal Article
Open access
PDF file
TOThomas Oswald
Thomas Oswald
SMSamuel Malomo
Samuel Malomo
TAThomas Alway
Thomas Alway
SHStanislav Hadjivassilev
Stanislav Hadjivassilev
SCSteve Coombs
Steve Coombs
ALAlexander Liu
Alexander Liu
Background: Sepsis survivors can develop left ventricular systolic dysfunction (LVSD) and heart failure. These patients are often treated with guideline-directed medical therapy (GDMT) known to be effective in patients with non-sepsis-related heart failure. This study sought to assess the use of GDMT on sepsis survivors with LVSD. Methods: Sepsis survivors with suspected myocardial injury and/or heart failure diagnosed with LVSD in a UK cardiac centre were retrospectively studied. Clinical and transthoracic echocardiography (TTE) data were recorded and analysed. Results: Of the 25 sepsis survivors (age 56 ± 11 years; 52% males), 11 (44%) had LVSD (LVEF < 50%). LV end-diastolic internal diameter (LVIDd) was similar between patients with vs. without LVSD (5.2 ± 0.8 cm vs. 4.7 ± 0.8 cm; p = 0.214). Patients with LVSD had significantly greater LV end-systolic internal diameter (LVIDs) than those without LVSD (4.0 ± 1.2 cm vs. 2.8 ± 0.6 cm; p = 0.027). Tricuspid annular plane systolic excursion (TAPSE) was similar between the two groups (2.1 ± 0.5 cm vs. 2.2 ± 0.6 cm; p = 0.910). Of the 11 patients with LVSD, nine patients underwent repeat TTE scans after 6 months [IQR 3–9], most of whom were taking GDMT. The majority (8/9) of these patients demonstrated LV systolic functional recovery (>5% LVEF increase; mean LVEF improvement 16 ± 11%) after GDMT. Reductions were seen in LVIDd (5.3 ± 0.8 cm to 5.0 ± 0.7 cm) and LVIDs (4.1 ± 1.2 cm to 3.7 ± 0.8 cm) after GDMT, though these changes did not reach statistical significance (both p > 0.05). Conclusions: GDMT appears beneficial in sepsis survivors with LV dysfunction. This finding should be validated on a larger and multi-centre basis to further affirm the value of medical therapy in post-sepsis heart failure.