Low Systemic Vascular Resistance Research Articles

Diastolic shock index: a novel prognostic parameter unveiling insights into vasodilatory cardiogenic shock

Abstract Introduction Systemic vasodilation is an increasingly acknowledged feature in cardiogenic shock (CS), defining a subset of patients with low systemic vascular resistances and higher vasopressor requirements. While a diastolic shock index (DSI) above 2.0 predicts vasoplegia and mortality in septic shock, its cut-off and prognostic significance in CS remain unclear. Our study aimed to characterize vasoplegia in CS using the DSI and assess its impact on prognosis. Methods Single-center retrospective cohort study on Cardiac Intensive Care Unit (CICU) admissions for CS from January 2017 to October 2023. Data included patient variables, CS features, vasoactive drugs, mechanical circulatory support, and 30-day mortality. DSI (heart rate (HR) to invasive diastolic blood pressure (DBP) ratio) impact on 30-day all-cause mortality was assessed with univariate Cox regression. Optimal DSI cut-off for adverse outcomes was determined through ROC curve analysis, and survival based on this cut-off was analyzed using Kaplan-Meier curves. Results 185 patients (mean age 59 ± 12 years, 63% male) were included. Acute myocardial infarction-related CS (47%) and heart failure-related CS (29%) were predominant. According to SCAI classification, 86% were class C, 22% class D, and 4% class E, with 26% experiencing previous cardiac arrest. Median Vasoactive-Inotropic Score (VIS) was 48 (IQR 21-85), and 25% used mechanical circulatory support. At admission, median HR was 105 bpm (IQR 90-125), DBP was 60 mmHg (IQR 55-65), and DSI was 1.71 (IQR 1.31-2.18). Thirty-day all-cause mortality was 36% (n=67), with median time to death of 4 days (IQR 1-10). DSI at 30 days predicted mortality (OR 1.42, 95%CI 1.06-1.91, p=0.020). DSI showed fair discriminative power for 30-day mortality (C-Statistic 0.60, 95% CI 0.51-0.68, p=0.031) with a cut-off of 2.2. Patients with DSI >2.2 exhibited heightened likelihood of prior cardiac arrest (38% vs. 20%, p=0.032), and higher serum lactate (5.5 vs. 3.9 mmol/L, p=0.008), and serum creatinine (2.64 vs. 1.88 mg/dL, p=0.003) at admission. Despite higher VIS at 48 hours (120±136 vs. 65±93.9, p=0.04), MCS need did not significantly differ. This group had superior 30-day mortality risk (log-rank p=0.011). Conclusion In our cohort, the admission Diastolic Shock Index (DSI) emerged as a promising identifier for CS vasoplegic patients and was a predictor of a higher risk for mortality. A DSI above 2.2 identified a subset of patients with previous cardiac arrest and higher lactate levels, enlightening possible risk factors associated with vasoplegia. Further studies are warranted to establish the robustness of this novel prognostic parameter in CS patients and its therapeutic implications.

Pathophysiologic Vasodilation in Cardiogenic Shock and Its Impact on Mortality.

Cardiogenic shock (CS) mortality remains near 40%. In addition to inadequate cardiac output, patients with severe CS may exhibit vasodilation. We aimed to examine the prevalence and consequences of vasodilation in CS. We analyzed all patients hospitalized at a CS referral center who were diagnosed with CS stages B to E and did not have concurrent sepsis or recent cardiac surgery. Vasodilation was defined by lower systemic vascular resistance (SVR), higher norepinephrine equivalent dose, or a blunted SVR response to pressors. Threshold SVR values were determined by their relation to 14-day mortality in spline models. The primary outcome was death within 14 days of CS onset in multivariable-adjusted Cox models. This study included 713 patients with a mean age of 60 years and 27% females; 14-day mortality was 28%, and 38% were vasodilated. The median SVR was 1308 dynes•s•cm-5 (interquartile range, 870-1652), median norepinephrine equivalent was 0.11 µg/kg per minute (interquartile range, 0-0.2), and 28% had a blunted pressor response. Each 100-dynes•s•cm-5 decrease in SVR below 800 was associated with 20% higher mortality (adjusted hazard ratio, 1.23; P=0.004). Each 0.1-µg/kg per minute increase in norepinephrine equivalent dose was associated with 15% higher mortality (adjusted hazard ratio, 1.12; P<0.001). A blunted pressor response was associated with a nearly 2-fold mortality increase (adjusted hazard ratio, 1.74; P=0.003). Pathophysiologic vasodilation is prevalent in CS and independently associated with an increased risk of death. CS vasodilation can be identified by SVR <800 dynes•s•cm-5, high doses of pressors, or a blunted SVR response to pressors. Additional studies exploring mechanisms and treatments for CS vasodilation are needed.

ALM Resuscitation With Brain and Multiorgan Protection for Far-Forward Operations: Survival at Hypotensive Pressures.

Non-compressible torso hemorrhagic (NCTH) shock is the leading cause of potentially survivable trauma on the battlefield. New hypotensive drug therapies are urgently required to resuscitate and protect the heart and brain following NCTH. Our aim was to examine the strengths and limitations of permissive hypotension and discuss the development of small-volume adenosine, lidocaine, and Mg2+ (ALM) fluid resuscitation in rats and pigs. For review of permissive hypotension, a literature search was performed from inception up to November 2023 using PubMed, Cochrane, and Embase databases, with inclusion of animal studies, clinical trials and reviews with military and clinical relevance. For the preclinical study, adult female pigs underwent laparoscopic liver resection. After 30 minutes of bleeding, animals were resuscitated with 4 mL/kg 3% NaCl ± ALM bolus followed 60 minutes later with 4 h 3 mL/kg/h 0.9% NaCl ± ALM drip (n = 10 per group), then blood transfusion. Mean arterial pressure (MAP) and cardiac output (CO) were continuously measured via a left ventricular pressure catheter and pulmonary artery catheter, respectively. Systemic vascular resistance (SVR) was calculated using the formula: 80 × (MAP - CVP)/CI. Oxygen delivery was calculated as the product of CO and arterial oxygen content. Targeting a MAP of ∼50 mmHg can be harmful or beneficial, depending on how CO and SVR are regulated. A theoretical example shows that for the same MAP of 50 mmHg, a higher CO and lower SVR can lead to a nearly 2-fold increase in O2 supply. We further show that in animal models of NCTH, 3% NaCl ALM bolus and 0.9% NaCl ALM drip induce a hypotensive, high flow, vasodilatory state with maintained tissue O2 supply and neuroprotection. ALM therapy increases survival by resuscitating the heart, reducing internal bleeding by correcting coagulopathy, and decreasing secondary injury. In rat and pig models of NCTH, small-volume ALM therapy resuscitates at hypotensive pressures by increasing CO and reducing SVR. This strategy is associated with heart and brain protection and maintained tissue O2 delivery. Translational studies are required to determine reproducibility and optimal component dosing. ALM therapy may find wide utility in prehospital and far-forward military environments.

Signs of Hemolysis Predict Mortality and Ventilator Associated Pneumonia in Severe Acute Respiratory Distress Syndrome Patients Undergoing Veno-Venous Extracorporeal Membrane Oxygenation.

Cell-free hemoglobin (CFH) is used to detect hemolysis and was recently suggested to trigger acute lung injury. However, its role has not been elucidated in severe acute respiratory distress syndrome (ARDS) patients undergoing extracorporeal membrane oxygenation (ECMO). We investigated the association of carboxyhemoglobin (COHb) and haptoglobin-two indirect markers of hemolysis-with mortality in critically ill patients undergoing veno-venous ECMO (VV-ECMO) with adjusted and longitudinal models (primary aim). Secondary aims included assessment of association between COHb and haptoglobin with the development of ventilator-associated pneumonia (VAP) and with hemodynamics. We retrospectively collected physiological, laboratory biomarkers, and outcome data in 147 patients undergoing VV-ECMO for severe ARDS. Forty-seven patients (32%) died in the intensive care unit (ICU). Average levels of COHb and haptoglobin were higher and lower, respectively, in patients who died. Higher haptoglobin was associated with lower pulmonary (PVR) and systemic vascular resistance, whereas higher COHb was associated with higher PVR. Carboxyhemoglobin was an independent predictor of VAP. Both haptoglobin and COHb independently predicted ICU mortality. In summary, indirect signs of hemolysis including COHb and haptoglobin are associated with modulation of vascular tone, VAP, and ICU mortality in respiratory ECMO. These findings suggest that CFH may be a mechanism of injury in this patient population.

Electrophysiology of Human iPSC-derived Vascular Smooth Muscle Cells and Cell-autonomous Consequences of Cantú Syndrome Mutations.

Cantú syndrome (CS), a multisystem disease with a complex cardiovascular phenotype, is caused by gain-of-function (GoF) variants in the Kir6.1/SUR2 subunits of ATP-sensitive potassium (KATP) channels and is characterized by low systemic vascular resistance, as well as tortuous, dilated, vessels, and decreased pulse-wave velocity. Thus, CS vascular dysfunction is multifactorial, with both hypomyotonic and hyperelastic components. To dissect whether such complexities arise cell autonomously within vascular smooth muscle cells (VSMCs) or as secondary responses to the pathophysiological milieu, we assessed electrical properties and gene expression in human induced pluripotent stem cell-derived VSMCs (hiPSC-VSMCs), differentiated from control and CS patient-derived hiPSCs, and in native mouse control and CS VSMCs. Whole-cell voltage clamp of isolated aortic and mesenteric arterial VSMCs isolated from wild-type (WT) and Kir6.1[V65M] (CS) mice revealed no clear differences in voltage-gated K+ (Kv) or Ca2+ currents. Kv and Ca2+ currents were also not different between validated hiPSC-VSMCs differentiated from control and CS patient-derived hiPSCs. While pinacidil-sensitive KATP currents in control hiPSC-VSMCs were similar to those in WT mouse VSMCs, they were considerably larger in CS hiPSC-VSMCs. Under current-clamp conditions, CS hiPSC-VSMCs were also hyperpolarized, consistent with increased basal K conductance and providing an explanation for decreased tone and decreased vascular resistance in CS. Increased compliance was observed in isolated CS mouse aortae and was associated with increased elastin mRNA expression. This was consistent with higher levels of elastin mRNA in CS hiPSC-VSMCs and suggesting that the hyperelastic component of CS vasculopathy is a cell-autonomous consequence of vascular KATP GoF. The results show that hiPSC-VSMCs reiterate expression of the same major ion currents as primary VSMCs, validating the use of these cells to study vascular disease. Results in hiPSC-VSMCs derived from CS patient cells suggest that both the hypomyotonic and hyperelastic components of CS vasculopathy are cell-autonomous phenomena driven by KATP overactivity within VSMCs .

Short-Chain Fatty Acid Butyrate Is an Inotropic Agent With Vasorelaxant and Cardioprotective Properties.

The heart can metabolize the microbiota-derived short-chain fatty acid butyrate. Butyrate may have beneficial effects in heart failure, but the underlying mechanisms are unknown. We tested the hypothesis that butyrate elevates cardiac output by mechanisms involving direct stimulation of cardiac contractility and vasorelaxation in rats. We examined the effects of butyrate on (1) invivo hemodynamics using parallel echocardiographic and invasive blood pressure measurements, (2) isolated perfused hearts in Langendorff systems under physiological conditions and after ischemia and reperfusion, and (3) isolated coronary arteries mounted in isometric wire myographs. We tested Na-butyrate added to injection solutions or physiological buffers and compared its effects with equimolar doses of NaCl. Butyrate at plasma concentrations of 0.56 mM increased cardiac output by 48.8±14.9%, stroke volume by 38.5±12.1%, and left ventricular ejection fraction by 39.6±6.2%, and lowered systemic vascular resistance by 33.5±6.4% without affecting blood pressure or heart rate invivo. In the range between 0.1 and 5 mM, butyrate increased left ventricular systolic pressure by up to 23.7±3.4% in isolated perfused hearts and by 9.4±2.9% following ischemia and reperfusion, while reducing myocardial infarct size by 81.7±16.9%. Butyrate relaxed isolated coronary septal arteries concentration dependently with an EC50=0.57 mM (95% CI, 0.23-1.44). We conclude that butyrate elevates cardiac output through mechanisms involving increased cardiac contractility and vasorelaxation. This effect of butyrate was not associated with adverse myocardial injury in damaged hearts exposed to ischemia and reperfusion.

Digital thermography complements Laser Speckle Contrast Imaging for the diagnosis of quantified severe mesenteric traction syndrome — A prospective cohort study

IntroductionThe diagnosis of severe mesenteric traction syndrome (MTS) is based on assessing the developed degree of facial flushing. Only one validated objective diagnostic method, Laser Speckle Contrast Imaging (LSCI), exists. However, this method is sensitive to distance, motion, and angulation. Digital thermography is known to correlate well with LSCI without the same limitations, but has never been tested in relation to MTS. This study aimed to examine the thermographic changes during the development of severe MTS and to calculate a cut-off value for identifying severe MTS. MethodsA prospective cohort study was performed on patients planned for open esophagectomy and pancreatic surgery from March 2021 to April 2022. All patients underwent continuous measurement on their forehead using LSCI and digital thermography during the first hour of surgery. The validated LSCI cut-off value was used to grade the severity of MTS. Blood samples and hemodynamics were collected at predefined time points. ResultsFifty-seven patients were included. Patients developing severe MTS had increased facial skin temperature 15 min (p = 0.002) and 30 min into surgery (p < 0.001). A cut-off value for identifying severe MTS using thermography was identified (35.55 °C, p < 0.001). Patients identified as developing severe MTS using this cut-off value had a higher level of prostacyclin (p = 0.001) and lower systemic vascular resistance (p < 0.001) 15 min into surgery, as compared with patients not developing severe MTS. ConclusionThis study shows that digital thermography may complement LSCI in the objective identification of severe MTS.

The “Preeclampsia and Hypertension Target Treatment” study: a multicenter prospective study to evaluate the effectiveness of the antihypertensive therapy based on maternal hemodynamic findings

Despite major advances in the pharmacologic treatment of hypertension in the nonpregnant population, treatments for hypertension in pregnancy have remained largely unchanged over the years. There is recent evidence that a more adequate control of maternal blood pressure is achieved when the first given antihypertensive drug is able to correct the underlying hemodynamic disorder of the mother besides normalizing the blood pressure values. This study aimed to compare the blood pressure control in women receiving an appropriate or inappropriate antihypertensive therapy following the baseline hemodynamic findings. This was a prospective multicenter study that included a population of women with de novo diagnosis of hypertensive disorders of pregnancy. A noninvasive assessment of the following maternal parameters was performed on hospital admission via Ultrasound Cardiac Output Monitor before any antihypertensive therapy was given: cardiac output, heart rate, systemic vascular resistance, and stroke volume. The clinician who prescribed the antihypertensive therapy was blinded to the hemodynamic evaluation and used as first-line treatment a vasodilator (nifedipine or alpha methyldopa) or a beta-blocker (labetalol) based on his preferences or on the local protocols. The first-line pharmacologic treatment was retrospectively considered hemodynamically appropriate in either of the following circumstances: (1) women with a hypodynamic profile (defined as low cardiac output [≤5 L/min] and/or high systemic vascular resistance [≥1300 dynes/second/cm2]) who were administered oral nifedipine or alpha methyldopa and (2) women with a hyperdynamic profile (defined as normal or high cardiac output [>5 L/min] and/or low systemic vascular resistances [<1300 dynes/second/cm2]) who were administered oral labetalol. The primary outcome of the study was to compare the occurrence of severe hypertension between women treated with a hemodynamically appropriate therapy and women treated with an inappropriate therapy. A total of 152 women with hypertensive disorders of pregnancy were included in the final analysis. Most women displayed a hypodynamic profile (114 [75.0%]) and received a hemodynamically appropriate treatment (116 [76.3%]). The occurrence of severe hypertension before delivery was significantly lower in the group receiving an appropriate therapy than in the group receiving an inappropriately treated (6.0% vs 19.4%, respectively; P=.02). Moreover, the number of women who achieved target values of blood pressure within 48 to 72 hours from the treatment start was higher in the group who received an appropriate treatment than in the group who received an inappropriate treatment (70.7% vs 50.0%, respectively; P=.02). In pregnant individuals with de novo hypertensive disorders of pregnancy, a lower occurrence of severe hypertension was observed when the first-line antihypertensive agent was tailored to the correct maternal hemodynamic profile.

Treatment of refractory shock with vitamin B12 : A narrative review.

High-dose vitamin B12 is a potential treatment for patients with vasodilatory shock that is refractory to other therapies. Vasodilatory shock is characterized by low blood pressure and low systemic vascular resistance. Nitric oxide and hydrogen sulfide, two potential targets of high-dose vitamin B12 given as hydroxocobalamin, facilitate this syndrome. This review explores the relationship between high-dose vitamin B12 and hemodynamic outcomes in adults with vasodilatory shock and provides an update on the literature since a 2019 review on this topic. A literature search of studies published in the past 5 years was conducted in the CINAHL, PubMed, Cochrane, and EMBASE databases in May 2023. After assessing for eligibility, eight studies met this review's inclusion criteria. Seven of the eight studies reported decreased vasopressor requirements for part or all of the study samples after receiving a hydroxocobalamin infusion. However, not all patients responded to hydroxocobalamin. These findings are limited by patient selection and differences in the timing of vasopressor requirement and blood pressure outcome assessments. The current evidence is promising as to whether vitamin B12 , given as a hydroxocobalamin infusion, may improve hemodynamic outcomes in vasodilatory shock, but the evidence is of low quality. The use of hydroxocobalamin to treat refractory, vasodilatory shock remains investigative. Larger randomized controlled trials are required to elucidate the role of vitamin B12 in treating refractory, vasodilatory shock, including in conjunction with other alternative therapies such as methylene blue and corticosteroids.

Extracorporeal Membrane Oxygenation for Septic Shock in Adults and Children: A Narrative Review.

Refractory septic shock is associated with a high risk of death. Circulatory support in the form of veno-arterial extracorporeal membrane oxygenation (VA ECMO) may function as a bridge to recovery, allowing for the treatment of the source of the sepsis. Whilst VA ECMO has been accepted as the means of hemodynamic support for children, in adults, single center observational studies show survival rates of only 70-90% for hypodynamic septic shock. The use of VA ECMO for circulatory support in hyperdynamic septic shock with preserved cardiac output or when applied late during cardio-pulmonary resuscitation is not recommended. With unresolving septic shock and a loss of ventriculo-arterial coupling, stress cardiomyopathy often develops. If the cardiac index (CI) approaches subnormal levels (CI < 2.5 L/min m-2) that do not match low systemic vascular resistance with a resulting loss of vital systemic perfusion pressure, VA ECMO support should be considered. A further decrease to the level of cardiogenic shock (CI < 1.8 L/min m-2) should be regarded as an indication for VA ECMO insertion. For patients who maintain a normal-to-high CI as part of their refractory vasoparalysis, VA ECMO support is justified in children and possibly in patients with a low body mass index. Extracorporeal support for septic shock should be limited to high-volume ECMO centers.

Temporary Mechanical Circulatory Support in Sepsis-Associated Cardiogenic Shock With and Without Acute Myocardial Infarction

To describe the current use and outcomes of temporary mechanical circulatory support (MCS) in patients with sepsis-associated cardiogenic shocks with and without acute myocardial infarction (AMI) in the United States. Retrospective cohort study. The National Inpatient Sample database from 2017 to 2019. Adult patients with sepsis-associated cardiogenic shock with and without AMI. Temporary MCSs, including intra-aortic balloon pump (IABP), percutaneous left ventricular assist device (pLVAD), and extracorporeal membrane oxygenation (ECMO). Multivariate logistic regression analyses adjusting for patient characteristics, organ failures, and socioeconomic status. Although the uses of IABP and pLVAD were associated with significantly lower odds of in-hospital mortality in patients with sepsis-associated cardiogenic shock (IABP: adjusted odds ratio [aOR] 0.57, 95% CI 0.44-0.73, p < .001; pLVAD: aOR 0.66, 95% CI 0.45-0.98, p=.037), ECMO was not (aOR 1.51, 95% CI 0.93-2.45, p=0.096). In the subgroup with AMI, temporary MCSs were not associated with significantly lower or higher odds of in-hospital mortality. In the subgroup without AMI, IABP was associated with significantly lower odds of in-hospital mortality (aOR 0.43, 95% CI 0.28-0.65, p < 0.001). Although temporary MCS is deemed to be a feasible option in sepsis-associated cardiogenic shock, the selection of the right patients whose shock is driven mainly by cardiogenic shock rather than septic shock, as represented by low cardiac output and high systemic vascular resistance, plays a critical role in the feasibility of this approach in the absence of clinical trials.

SPECT for risk stratification in patients with advanced liver disease

BackgroundPatients with advanced liver disease (ALD) have unique hemodynamics including high resting cardiac output and low systemic vascular resistance which may reduce the sensitivity of pharmacological myocardial perfusion imaging (MPI). MPI is frequently ordered for patients with ALD if liver transplantation is being considered. Because of the limited data on effectiveness of MPI in the ALD population, we conducted this cohort study focused on cardiac outcomes after pharmacological MPI. MethodsWe conducted a cohort study comparing normal versus abnormal MPI among 454 patients with ALD between 1/1/2011 and 06/01/2021 at a single tertiarycare academic medical center. Abnormal MPI was defined as summed stress score > 2 on LVEF < 40 %. The primary outcome was to compare the frequency of major adverse cardiovascular events (MACEs) among ALD patients with and without abnormal MPI. Secondary outcome included individual components of MACE analyzed by chi square. Kaplan-Meier survival curves and a logistic-regression model of associations with MACE were also performed. ResultsIn this cohort, 58 patients were observed to have an abnormal MPI. Baseline characteristics between the groups were similar, except prior coronary disease, which was more common among the abnormal MPI group (risk ratio 2.07, 95 % confidence interval 1.30–3.30, P = 0.003). MACE was more common in the group with abnormal MPI (n = 24, 41.4 % versus normal MPI n = 104, 26.3 %, P < .001). No difference in MACE was observed when stratified by liver disease type. In the logistic regression model, diabetes mellitus, stage 3 chronic kidney disease, and summed stress score >2 were retained as being associated with MACE. ConclusionsOur data suggest that MPI remains an effective test for identifying ALD patients at higher risk of mortality and cardiac events. Further study is needed to understand whether a strategy of routine MPI for liver transplant candidates effectively improves long term survival.

Ketone body 3-hydroxybutyrate elevates cardiac output through peripheral vasorelaxation and enhanced cardiac contractility

The ketone body 3-hydroxybutyrate (3-OHB) increases cardiac output and myocardial perfusion without affecting blood pressure in humans, but the cardiovascular sites of action remain obscure. Here, we test the hypothesis in rats that 3-OHB acts directly on the heart to increase cardiac contractility and directly on blood vessels to lower systemic vascular resistance. We investigate effects of 3-OHB on (a) in vivo hemodynamics using echocardiography and invasive blood pressure measurements, (b) isolated perfused hearts in Langendorff systems, and (c) isolated arteries and veins in isometric myographs. We compare Na-3-OHB to equimolar NaCl added to physiological buffers or injection solutions. At plasma concentrations of 2–4 mM in vivo, 3-OHB increases cardiac output (by 28.3±7.8%), stroke volume (by 22.4±6.0%), left ventricular ejection fraction (by 13.3±4.6%), and arterial dP/dtmax (by 31.9±11.2%) and lowers systemic vascular resistance (by 30.6±11.2%) without substantially affecting heart rate or blood pressure. Applied to isolated perfused hearts at 3–10 mM, 3-OHB increases left ventricular developed pressure by up to 26.3±7.4 mmHg and coronary perfusion by up to 20.2±9.5%. Beginning at 1–3 mM, 3-OHB relaxes isolated coronary (EC50=12.4 mM), cerebral, femoral, mesenteric, and renal arteries as well as brachial, femoral, and mesenteric veins by up to 60% of pre-contraction within the pathophysiological concentration range. Of the two enantiomers that constitute racemic 3-OHB, D-3-OHB dominates endogenously; but tested separately, the enantiomers induce similar vasorelaxation. We conclude that increased cardiac contractility and generalized systemic vasorelaxation can explain the elevated cardiac output during 3-OHB administration. These actions strengthen the therapeutic rationale for 3-OHB in heart failure management.

Incidence of Intraoperative Vasoplegic Syndrome in Lung Transplantation

Severe hypotension and low systemic vascular resistance in the setting of adequate cardiac output, known as "vasoplegic syndrome" (VS), is a physiologic disturbance reported in 9% to 44% of cardiac surgery patients. Although this phenomenon is well-documented in cardiac surgery, there are few studies on its occurrence in lung transplantation. The goal of this study was to characterize the incidence of VS in lung transplantation, as well as identify associated risk factors and outcomes. Retrospective study of single and bilateral lung transplants from April 2013 to September 2021. The study was conducted at an academic hospital. Patients ≥18 years of age who underwent lung transplantation. None. The authors defined VS as mean arterial pressure <65 mmHg, cardiac index ≥2.2 L/min/m2, and ≥30 minutes of vasopressor administration after organ reperfusion. The association between VS and risk factors or outcomes was assessed using t tests, Mann-Whitney U, and chi-square tests. The authors ran multivariate logistic regression models to determine factors independently associated with VS. The incidence of VS was 13.9% (CI 10.4%-18.4%). In the multivariate model, male sex (odds ratio 2.85, CI 1.07-7.58, p=0.04) and cystic fibrosis (odds ratio 5.76, CI 1.43-23.09, p=0.01) were associated with VS. The incidence of VS in lung transplantation is comparable to that of cardiac surgery. Interestingly, male sex and cystic fibrosis are strong risk factors. Identifying lung transplant recipients at increased risk of VS may be crucial to anticipating intraoperative complications.

Vasoplegic Syndrome and Anaesthesia: A Narrative Review.

Vasoplegic syndrome (VS) is defined as low systemic vascular resistance, normal or high cardiac output, and resistant hypotension unresponsive to vasopressor agents and intravenous volume. VS is a frequently encountered complication in cardiovascular and transplantation surgery, burns, trauma, pancreatitis, and sepsis. The basis of the pathophysiology is associated with an imbalance of vasodilator and vasoconstrictive structure in vascular smooth muscle cells and is highly complex. The pathogenesis of VS has several mechanisms, including overproduction of iNO, stimulation of ATP-dependent K+ channels and NF-κB, and vasopressin receptor 1A (V1A-receptor) down-regulation. Available treatments involve volume and inotropes administration, vasopressin, methylene blue, hydroxocobalamin, Ca++, vitamin C, and thiamine, and should also restore vascular tone and improve vasoplegia. Other treatments could include angiotensin II, corticosteroids, NF-κB inhibitor, ATP-dependent K+ channel blocker, indigo carmine, and hyperbaric oxygen therapy. Despite modern advances in treatment, the mortality rate is still 30-50%. It is challenging for an anaesthesiologist to consider this syndrome's diagnosis and manage its treatment. Our review aims to review the diagnosis, predisposing factors, pathophysiology, treatment, and anaesthesia approach of VS during anaesthesia and to suggest a treatment algorithm.

Causes and prognosis analysis of hyperdynamic left ventricular ejection fraction in intensive care unit patients with sepsis

To analyze the causes of hyperdynamic left ventricular ejection fraction (LVEF) in sepsis patients in the intensive care unit (ICU) and its impact on prognosis. A retrospective cohort study was conducted. The clinical data of 273 sepsis patients admitted to the department of critical care medicine of the Affiliated People's Hospital of Jiangsu University from January 2018 to October 2021 were collected including gender, age, severity score, comorbidities, source of infection, vital signs, transthoracic echocardiographic (TTE) parameters, fluid intake and output, vasoactive drug dose, therapeutic measures and prognostic indicators. The patients were divided into normal LVEF group (LVEF 0.55-0.70), low LVEF group (LVEF < 0.55) and hyperdynamic LVEF group (LVEF > 0.70) according to the TTE examination results within 7 days of ICU admission. The clinical indicators among the three groups were compared and analyzed, and multivariate Logistic regression analysis was used to screen risk factors for the development of hyperdynamic LVEF in patients with sepsis. Spearman correlation analysis was used to determine the correlation between the mortality of different types of LVEF and clinical variables. Among 273 patients, 20 patients with severe valvular or cardiomyopathy at admission and those who did not completed cardiac ultrasound within 7 days of ICU admission were excluded. A total of 253 patients were finally enrolled, including 169 patients in the normal LVEF group, 40 patients in the low LVEF group, and 44 patients in the hyperdynamic LVEF group. There were statistically significant differences in age, sequential organ failure assessment (SOFA) score, central venous pressure (CVP), heart rate (HR), oxygenation index (PaO2/FiO2), blood lactate (Lac), urine output, vasoactive drug dose, ratio of hypertension, ischemic heart disease, chronic liver disease, cancer, invasive mechanical ventilation and renal replacement therapy (RRT), and incidence of septic shock among the different types of LVEF groups. TTE results analysis showed that the hyperdynamic LVEF group had higher stroke volume (SV) and cardiac index (CI) than those in the normal LVEF and low LVEF groups, lower systemic vascular resistance (SVR) than that in the normal LVEF and low LVEF groups, and an increased E/A ratio. The 90-day mortality in the hyperdynamic LVEF group was significantly higher than that in the normal LVEF and low LVEF groups [59.1% (26/44) vs. 24.9% (42/169), 32.5% (13/40), both P < 0.05]. Multivariate Logistic regression analysis showed that chronic liver disease [odds ratio (OR) = 1.712, 95% confidence interval (95%CI) was 0.912-3.234, P < 0.001], cancer (OR = 2.784, 95%CI was 1.296-6.151, P < 0.001), HR (OR = 1.026, 95%CI was 1.014-1.038, P < 0.001), vasoactive drug dose (OR = 1.133, 95%CI was 1.009-1.291, P < 0.001), and invasive mechanical ventilation (OR = 2.141, 95%CI was 1.285-3.651, P < 0.001) were independent factors for hyperdynamic LVEF in ICU sepsis patients. Correlation analysis showed that the mortality of hyperdynamic LVEF, normal LVEF and low LVEF patients was positively correlated with vasoactive drug dose (r value was 0.251, 0.361, 0.289, respectively, all P < 0.001). The mortality of the hyperdynamic LVEF patients was negatively correlated with SVR (r = -0.545, P < 0.001). Chronic liver disease, cancer, HR, vasoactive drugs dose, and invasive mechanical ventilation are independent risk factors for hyperdynamic LVEF in patients with sepsis. Hyperdynamic LVEF is positively associated with mortality in sepsis patients, which may be due to the the decrease of SVR caused by septic vascular paralysis.

Vasoplegia: A Review.

Vasoplegia is a condition characterized by persistent low systemic vascular resistance despite a normal or high cardiac index, resulting in profound and uncontrolled vasodilation. Vasoplegia may occur due to various conditions, including cardiac failure, sepsis, and post-cardiac surgery. In the cardiac cohort, multiple risk factors for vasoplegia have been identified. Several factors contribute to the pathophysiology of this condition, and various mechanisms have been proposed, including nitric oxide, adenosine, prostanoids, endothelins, the renin-angiotensin-aldosterone system, and hydrogen sulfide. Early identification and prompt management of vasoplegia is crucial to prevent development of shock. This review expands upon the different vasopressors used in management of vasoplegia, including catecholamines such as norepinephrine, dopamine, epinephrine, phenylephrine, and other agents including vasopressin, methylene blue, angiotensin II, hydroxocobalamin, vitamin C, thiamine, and corticosteroids (ie, hydrocortisone). It also emphasizes the importance of conducting further research and making advancements in treatment regimens for vasoplegia.

Low length-for-age Z-score within 1 month after birth predicts hyperdynamic circulation at the age of 21 years in rural Malawi

Low birth weight predisposes to the development of hypertension in middle- and high-income countries. We examined the relation of early life length-for-age score (Z-score) on cardiovascular function in young adults in Malawi, a low-income country. Capture of supine, seated, and standing brachial pulse waveforms (Mobil-O-Graph) were performed in 223 females and 152 males (mean age 21 years), and analyzed according to the length-for-age Z-score tertiles during the first month of life. Plasma LDL cholesterol in young adulthood was slightly lower in the lowest versus highest tertile. Otherwise, blood hemoglobin and plasma chemistry were similar in all tertiles. Irrespective of posture, blood pressure, forward and backward wave amplitudes, and pulse wave velocity were corresponding in all tertiles. In the three postures, the lowest tertile presented with 4.5% lower systemic vascular resistance than the highest tertile (p = 0.005), and 4.4% and 5.5% higher cardiac output than the middle and highest tertiles, respectively (p < 0.01). Left cardiac work was 6.8% and 6.9% higher in the lowest tertile than in the middle and highest tertiles, respectively (p < 0.01). To conclude, in a low-income environment, low length-for-age Z-score after birth predicted hyperdynamic circulation at 21 years of age without changes in blood pressure and metabolic variables.

The Outcome of Electrical Cardioversion in Hyperthyroid Induced Atrial Fibrillation.

Hyperthyroidism is a prevalent cause of atrial fibrillation (AF). High cardiac output with low systemic vascular resistance, driven by hyperthyroidism, is associated with a rapid heartbeat, enhanced left ventricular systolic and diastolic function, and a higher incidence of supraventricular tachyarrhythmias. After returning to euthyroid status, hyperthyroidism-induced AF generally spontaneously reverts to sinus rhythm (SR), and a significant number of patients remain in chronic AF and require electrical cardioversion (ECV). After effective cardioversion, the long-term outcome of hyperthyroidism-induced persistent AF is unknown. Early ECV before the antithyroid medication should be explored for hyperthyroidism-induced AF to reduce the risk of thromboembolic consequences. The recurrence rate of AF between Hyperthyroid and Euthyroid Patients after ECV did not significantly differ. This review article compares the recurrence rate of AF as an outcome of ECV in Hyperthyroid induced atrial fibrillation.

Are There Distinct Cardiovascular Subclasses in Acute Respiratory Distress Syndrome? Maybe.

Are There Distinct Cardiovascular Subclasses in Acute Respiratory Distress Syndrome? Maybe.