Zied Ltaief

Bio: Zied Ltaief is an academic researcher from University of Lausanne. The author has contributed to research in topics: Medicine & Anesthesia. The author has an hindex of 2, co-authored 5 publications receiving 12 citations.

Use of oscillometric devices in atrial fibrillation: a comparison of three devices and invasive blood pressure measurement.

Abstract: Background: The use of automated (oscillometric) blood pressure (BP) devices is not validated in atrial fibrillation (AF) patients.Objectives: To assess the reliability of three oscillometric BP de...

Therapeutic anticoagulation to prevent thrombosis, coagulopathy, and mortality in severe COVID‐19: The Swiss COVID‐HEP randomized clinical trial

Abstract: Hospitalized patients with COVID‐19 suffered initially from high rates of venous thromboembolism (VTE), with possible associations between therapeutic anticoagulation and better clinical outcomes in observational studies.

Hyperoxia during extracorporeal cardiopulmonary resuscitation for refractory cardiac arrest is associated with severe circulatory failure and increased mortality.

Abstract: BACKGROUND High levels of arterial oxygen pressures (PaO2) have been associated with increased mortality in extracorporeal cardiopulmonary resuscitation (ECPR), but there is limited information regarding possible mechanisms linking hyperoxia and death in this setting, notably with respect to its hemodynamic consequences. We aimed therefore at evaluating a possible association between PaO2, circulatory failure and death during ECPR. METHODS We retrospectively analyzed 44 consecutive cardiac arrest (CA) patients treated with ECPR to determine the association between the mean PaO2 over the first 24 h, arterial blood pressure, vasopressor and intravenous fluid therapies, mortality, and cause of deaths. RESULTS Eleven patients (25%) survived to hospital discharge. The main causes of death were refractory circulatory shock (46%) and neurological damage (24%). Compared to survivors, non survivors had significantly higher mean 24 h PaO2 (306 ± 121 mmHg vs 164 ± 53 mmHg, p < 0.001), lower mean blood pressure and higher requirements in vasopressors and fluids, but displayed similar pulse pressure during the first 24 h (an index of native cardiac recovery). The mean 24 h PaO2 was significantly and positively correlated with the severity of hypotension and the intensity of vasoactive therapies. Patients dying from circulatory failure died after a median of 17 h, compared to a median of 58 h for patients dying from a neurological cause. Patients dying from neurological cause had better preserved blood pressure and lower vasopressor requirements. CONCLUSION In conclusion, hyperoxia is associated with increased mortality during ECPR, possibly by promoting circulatory collapse or delayed neurological damage.

Pathophysiology and clinical implications of the veno-arterial PCO2 gap.

Abstract: Circulatory shock is common among patients admitted to the intensive care unit and, despite improved medical management, remains associated with a high mortality rate. Under these circumstances, tissue perfusion and cellular oxygenation are commonly assessed by blood lactate and venous oxygen saturation (SvO2). Venous-to-arterial difference in CO2 partial pressure (Pv-aCO2 gap) is another parameter, which can easily be obtained (through simultaneous sampling of central or mixed venous and arterial blood) and appears to have prognostic abilities in several types of shock. The Pv-aCO2 gap can provide insight into the adequacy of cardiac output relative to oxygen consumption and represents a link between the macro- and microcirculation. Correct interpretation of the Pv-aCO2 gap at the bedside, however, requires an understanding of CO2 physiology and of elements modulating the relationship between CO2 content and its partial pressure (Haldane effect, acidosis, anemia...). In this chapter, we review the physiological basis underlying CO2 production, transport and blood content, as well as the clinical implications of an increased Pv-aCO2 gap. We review the evidence linking Pv-aCO2 gap to clinical outcomes and, finally, we propose algorithms guiding the interpretation of Pv-aCO2 in different types of dysoxia.

The Right Ventricle in COVID-19

Abstract: Infection with the novel severe acute respiratory coronavirus-2 (SARS-CoV2) results in COVID-19, a disease primarily affecting the respiratory system to provoke a spectrum of clinical manifestations, the most severe being acute respiratory distress syndrome (ARDS). A significant proportion of COVID-19 patients also develop various cardiac complications, among which dysfunction of the right ventricle (RV) appears particularly common, especially in severe forms of the disease, and which is associated with a dismal prognosis. Echocardiographic studies indeed reveal right ventricular dysfunction in up to 40% of patients, a proportion even greater when the RV is explored with strain imaging echocardiography. The pathophysiological mechanisms of RV dysfunction in COVID-19 include processes increasing the pulmonary vascular hydraulic load and others reducing RV contractility, which precipitate the acute uncoupling of the RV with the pulmonary circulation. Understanding these mechanisms provides the fundamental basis for the adequate therapeutic management of RV dysfunction, which incorporates protective mechanical ventilation, the prevention and treatment of pulmonary vasoconstriction and thrombotic complications, as well as the appropriate management of RV preload and contractility. This comprehensive review provides a detailed update of the evidence of RV dysfunction in COVID-19, its pathophysiological mechanisms, and its therapy.

Accuracy of automated blood pressure measurements in the presence of atrial fibrillation: systematic review and meta-analysis.

Abstract: Atrial fibrillation (AF) affects ~3% of the general population and is twice as common with hypertension. Validation protocols for automated sphygmomanometers exclude people with AF, raising concerns over accuracy of hypertension diagnosis or management, using out-of-office blood pressure (BP) monitoring, in the presence of AF. Some devices include algorithms to detect AF; a feature open to misinterpretation as offering accurate BP measurement with AF. We undertook this review to explore accuracy of automated devices, with or without AF detection, for measuring BP. We searched Medline and Embase to October 2018 for studies comparing automated BP measurement devices to a standard mercury sphygmomanometer contemporaneously. Data were extracted by two reviewers. Mean BP differences between devices and mercury were calculated, where not reported and compared; meta-analyses were undertaken where possible. We included 13 studies reporting 14 devices. Mean systolic and diastolic BP differences from mercury ranged from −3.1 to + 6.1/−4.6 to +9.0 mmHg. Considerable heterogeneity existed between devices (I2: 80 to 90%). Devices with AF detection algorithms appeared no more accurate for BP measurement with AF than other devices. A previous review concluded that oscillometric devices are accurate for systolic but not diastolic BP measurement in AF. The present findings do not support that conclusion. Due to heterogeneity between devices, they should be evaluated on individual performance. We found no evidence that devices with AF detection measure BP more accurately in AF than other devices. More home or ambulatory automated BP monitors require validation in populations with AF.

Blood pressure measurement in atrial fibrillation: review and meta-analysis of evidence on accuracy and clinical relevance.

Abstract: Atrial fibrillation (AF) often coexists with hypertension in the elderly and multiplies the risk of stroke and death. Blood pressure (BP) measurement in patients with AF is difficult and uncertain and has been a classic exclusion criterion in hypertension clinical trials leading to limited research data. This article reviews the evidence on the accuracy of BP measurement in AF performed using different methods (office, ambulatory, home) and devices (auscultatory, oscillometric) and its clinical relevance in predicting cardiovascular damage. The current evidence suggests the following: (i) Interobserver and intra-observer variation in auscultatory BP measurement is increased in AF because of increased beat-to-beat BP variability and triplicate measurement is required; (ii) Data from validation studies of automated electronic BP monitors in AF are limited and methodologically heterogeneous and suggest reasonable accuracy in measuring SBP and a small yet consistent overestimation of DBP; (iii) 24-h ambulatory BP monitoring is feasible in AF, with similar proportion of errors as in individuals without AF; (iv) both auscultatory and automated oscillometric BP measurements appear to be clinically relevant in AF, providing similar associations with intra-arterial BP measurements and with indices of preclinical cardiac damage as in patients without AF, and predict cardiovascular events and death; (v) Screening for AF in the elderly using an AF-specific algorithm during routine automated office, home or ambulatory BP measurement has high diagnostic accuracy. In conclusion, in AF patients, BP measurement is important, reliable, and clinically relevant and should not be neglected in clinical research and in practice.

2020 Consensus Statement of the Taiwan Hypertension Society and the Taiwan Society of Cardiology on Home Blood Pressure Monitoring for the Management of Arterial Hypertension.

Abstract: To facilitate the applications of home blood pressure (HBP) monitoring in clinical settings, the Taiwan Hypertension Society and the Taiwan Society of Cardiology jointly put forward the Consensus Statement on HBP monitoring according to up-to-date scientific evidence by convening a series of expert meetings and compiling opinions from the members of these two societies. In this Consensus Statement as well as recent international guidelines for management of arterial hypertension, HBP monitoring has been implemented in diagnostic confirmation of hypertension, identification of hypertension phenotypes, guidance of anti-hypertensive treatment, and detection of hypotensive events. HBP should be obtained by repetitive measurements based on the " 722 " principle, which is referred to duplicate blood pressure readings taken per occasion, twice daily, over seven consecutive days. The " 722" principle of HBP monitoring should be applied in clinical settings, including confirmation of hypertension diagnosis, 2 weeks after adjustment of antihypertensive medications, and at least every 3 months in well-controlled hypertensive patients. A good reproducibility of HBP monitoring could be achieved by individuals carefully following the instructions before and during HBP measurement, by using validated BP devices with an upper arm cuff. Corresponding to office BP thresholds of 140/90 and 130/80 mmHg, the thresholds (or targets) of HBP are 135/85 and 130/80 mmHg, respectively. HBP-based hypertension management strategies including bedtime dosing (for uncontrolled morning hypertension), shifting to drugs with longer-acting antihypertensive effect (for uncontrolled evening hypertension), and adding another antihypertensive drug (for uncontrolled morning and evening hypertension) should be considered. Only with the support from medical caregivers, paramedical team, or tele- monitoring, HBP monitoring could reliably improve the control of hypertension.

Therapeutic anticoagulation to prevent thrombosis, coagulopathy, and mortality in severe COVID‐19: The Swiss COVID‐HEP randomized clinical trial

Abstract: Hospitalized patients with COVID‐19 suffered initially from high rates of venous thromboembolism (VTE), with possible associations between therapeutic anticoagulation and better clinical outcomes in observational studies.

2022 Guidelines of the Taiwan Society of Cardiology and the Taiwan Hypertension Society for the Management of Hypertension.

Abstract: Hypertension is the most important modifiable cause of cardiovascular (CV) disease and all-cause mortality worldwide. Despite the positive correlations between blood pressure (BP) levels and later CV events since BP levels as low as 100/60 mmHg have been reported in numerous epidemiological studies, the diagnostic criteria of hypertension and BP thresholds and targets of antihypertensive therapy have largely remained at the level of 140/90 mmHg in the past 30 years. The publication of both the SPRINT and STEP trials (comprising > 8,500 Caucasian/African and Chinese participants, respectively) provided evidence to shake this 140/90 mmHg dogma. Another dogma regarding hypertension management is the dependence on office (or clinic) BP measurements. Although standardized office BP measurements have been widely recommended and adopted in large-scale CV outcome trials, the practice of office BP measurements has never been ideal in real-world practice. Home BP monitoring (HBPM) is easy to perform, more likely to be free of environmental and/or emotional stress, feasible to document long-term BP variations, of good reproducibility and reliability, and more correlated with hypertension-mediated organ damage (HMOD) and CV events, compared to routine office BP measurements. In the 2022 Taiwan Hypertension Guidelines of the Taiwan Society of Cardiology (TSOC) and the Taiwan Hypertension Society (THS), we break these two dogmas by recommending the definition of hypertension as ≥ 130/80 mmHg and a universal BP target of < 130/80 mmHg, based on standardized HBPM obtained according to the 722 protocol. The 722 protocol refers to duplicate BP readings taken per occasion ("2"), twice daily ("2"), over seven consecutive days ("7"). To facilitate implementation of the guidelines, a series of flowcharts encompassing assessment, adjustment, and HBPM-guided hypertension management are provided. Other key messages include that: 1) lifestyle modification, summarized as the mnemonic S-ABCDE, should be applied to people with elevated BP and hypertensive patients to reduce life-time BP burden; 2) all 5 major antihypertensive drugs (angiotensin-converting enzyme inhibitors [A], angiotensin receptor blockers [A], β-blockers [B], calcium-channel blockers [C], and thiazide diuretics [D]) are recommended as first-line antihypertensive drugs; 3) initial combination therapy, preferably in a single-pill combination, is recommended for patients with BP ≥ 20/10 mmHg above targets; 4) a target hierarchy (HBPM-HMOD- ambulatory BP monitoring [ABPM]) should be considered to optimize hypertension management, which indicates reaching the HBPM target first and then keeping HMOD stable or regressed, otherwise ABPM can be arranged to guide treatment adjustment; and 5) renal denervation can be considered as an alternative BP-lowering strategy after careful clinical and imaging evaluation.