In vivo tebuconazole administration impairs heart electrical function and facilitates the occurrence of dobutamine-induced arrhythmias: involvement of reactive oxygen species

Tebuconazole (TEB), a widely used pesticide in agriculture to combat fungal infections, is commonly detected in global food, potable water, groundwater, and human urine samples. Despite its known in vivo toxicity, its impact on heart function remains unclear. In a 28-day study on male Wistar rats (approximately 100 g), administering 10 mg/kg/day TEB or a vehicle (control) revealed no effect on body weight gain or heart weight, but an increase in the infarct area in TEB-treated animals. Notably, TEB induced time-dependent changes in in vivo electrocardiograms, particularly prolonging the QT interval after 28 days of administration. Isolated left ventricular cardiomyocytes exposed to TEB exhibited lengthened action potentials and reduced transient outward potassium current. TEB also increased reactive oxygen species (ROS) production in these cardiomyocytes, a phenomenon reversed by N-acetylcysteine (NAC). Furthermore, TEB-treated animals, when subjected to an in vivo dobutamine (Dob) and caffeine (Caf) challenge, displayed heightened susceptibility to severe arrhythmias, a phenotype prevented by NAC. In conclusion, TEB at the no observed adverse effect level (NOAEL) dose adversely affects heart electrical function, increases arrhythmic susceptibility, partially through ROS overproduction, and this phenotype is reversible by scavenging ROS with NAC.

The epidemiology of postoperative dobutamine and phosphodiesterase inhibitors after adult elective cardiac surgery and its impact on the length of hospital stay: a post hoc analysis from the multicenter retrospective observational study

The optimal administration of inotrope after cardiac surgery is unknown. This study aimed to investigate the impact of postoperative inotrope on clinical outcomes in adult elective cardiac surgery patients. Data from the Blood Pressure and Relative Optimal Target after Heart Surgery in Epidemiologic Registry study were analyzed, employing propensity score considering the hospital of admission. The primary outcome was the length of hospital stay evaluated using quantile regression. Secondary outcomes were kidney injury progression, renal replacement therapy, atrial fibrillation, mortality, mechanical ventilation duration, and length of intensive care unit (ICU) stay. Among 870 patients from 14 ICUs in Japan, 535 received inotropes within 24 h of ICU admission, with usage rates ranging from 40 to 100% among facilities. After propensity score matching, 218 patients were included in each group. The inotrope group had a significantly longer hospital stay compared to the control group (16 days vs. 14 days; median difference 1.78 [95% confidence interval [CI] 0.31-3.24]; p = 0.018). However, no significant differences were observed in the secondary outcomes, except for mechanical ventilation duration. The results of the sensitivity analysis using a mixed-effects quantile regression analysis considering the hospital of admission for length of hospital stay in the original cohort were consistent with the results of the propensity analyses (median difference in days, 2.35 [95% CI, 0.35-4.36]; p = 0.022). The use of inotropes within 24 h of ICU admission in adult elective cardiac surgery patients was associated with an extended hospitalization period of approximately 2 days, without offering any prognostic benefit. Clinical trial registration: UMIN-CTR, https://www.umin.ac.jp/ctr/index-j.htm , UMIN000037074.

Anaesthesia-related morbidity associated with recumbent, low-field magnetic resonance imaging of horses

CASE HISTORY

Medical records from 2009 to 2021 from a private equine referral hospital in Rochester, NH, USA were analysed for cases that underwent general anaesthesia for low-field MRI of the distal limb. These were used to determine peri-anaesthetic morbidity and mortality.

CLINICAL FINDINGS AND OUTCOME

Two hundred and forty-three anaesthetic episodes were recorded in horses undergoing low-field MRI. The peri-anaesthetic complication rate prior to discharge was 6.2% (15/243). No patients experienced a fatal complication. Ninety two of the 243 patients had multiple sites imaged, 90/243 received pre-anaesthetic dantrolene, 134/243 received intra-anaesthetic dobutamine, and 15/243 were positioned in dorsal recumbency. Complications included: abdominal discomfort ("colic"; 9/243), myopathy (4/243), hyphaema (1/243) and carpal fracture (1/243). At the time of discharge, 14/15 complications had resolved. Of 135 horses for which data were available 55 became hypotensive during the procedure (lowest mean arterial pressure < 65 mmHg). Median body weight was 553 (min 363, max 771) kg. Horses were anaesthetised for a median of 150 (min 45, max 210) minutes. There was no evidence of an association between higher body weight (p = 0.051) or longer duration of anaesthesia (p = 0.421) and development of an anaesthetic complication. For categorical variables (dantrolene administration pre-anaesthesia, dobutamine administration during anaesthesia, hypotension (mean < 65 mmHg) during anaesthesia, dorsal vs. lateral recumbency, and imaging of single vs. multiple sites), the 95% CI for the OR included 1, indicating a lack of effect of the variable on the odds of complication.

CLINICAL RELEVANCE

The cases included in this series suggest that low-field MRI under general anaesthesia is a viable option for diagnostic imaging in otherwise healthy horses. Complications occur, but most resolve before discharge.

Dobutamine Stress Cardiovascular Magnetic Resonance Derived 2-Dimension Feature Tracking Strain Analysis in Pediatric Population with Anomalous Aortic Origin of Right Coronary Artery

Anomalous aortic origin of right coronary artery (AAORCA) is associated with myocardial ischemia and sudden cardiac arrest/death. Risk stratification remains challenging and relies upon provocative test results. This study describes the utility of dobutamine stress cardiovascular magnetic resonance (DSCMR) and potential benefit of strain analysis in children with AAORCA. All patients less than 21 years of age with AAORCA who underwent DSCMR between July 2018 and December 2022 were included. Visual wall motion abnormalities (VWMA) at rest and during protocolized increments of dobutamine infusion were assessed. Regional and global left ventricular circumferential (GCS) and radial (GRS) strain using 2-dimension Feature tracking (2D-FT) analysis (cvi42, Circle Cardiovascular Imaging Inc.) were calculated at rest and peak response. Of the total 54 DSCMR studies performed in 51 children with median age (IQR) of 13.5 (11-15) years, FT analysis was reliably performed in 52 (96%) studies. None had VWMA. The absolute change in GCS and GRS from rest to peak dobutamine stress was 4% (1-6%) and 11% (4-18%), respectively. There was no significant difference in GCS and GRS in patients with exertional symptoms vs no/non-exertional symptoms as well as between those considered to be high-risk vs low-risk anatomical features. DSCMR-derived 2D-FT strain analysis is feasible to assess myocardial deformation in children with AAORCA and may enhance this method of provocative testing. Although there were no statically significant differences in GCS and GRS values between high and low-risk subgroups, the absolute change in GCS between rest and peak stress is diminished when compared to normal adult reports.

Independent predictors of true positivity of positive myocardial perfusion imaging

OBJECTIVE: The primary aim of the present study was to determine the success of single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) in detecting critical coronary artery disease (CAD) as identified by invasive coronary angiography (ICA), as well as to compare the positive predictive values (PPV) of different stress methods. Our secondary aim was to investigate demographic, laboratory, electrocardiographic, and echocardiographic variables that could predict true positive results. PATIENTS AND METHODS: The study was conducted with 317 consecutive patients. Exercise, dipyridamole, adenosine, or dobutamine were used as stress methods. According to the results of ICA, patients with and without critical CAD were divided into two groups and compared statistically. The independent predictors of true positive results of positive SPECT-MPI were determined using univariate and multivariate logistic regression analysis (MLRA). RESULTS: Among the patients, 129 (40.7%) were found to have critical CAD (+) and 188 (50.3%) critical CAD (-). The PPVs of different stress methods were similar. Age, diabetes, and monocyte to HDL ratio (MHR) were found to be independent predictors of critical CAD in MLRA (p<0.005, p=0.002, and p<0.005, respectively). ROC curve analysis revealed 81.4% sensitivity and 47.3% specificity (AUC: 0.683) at a cut-off of 57 for age and 72.1% sensitivity and 54.3% specificity (AUC: 0.649) for MHR at a cut-off of 9.7. CONCLUSIONS: The true positivity rate of SPECT-MPI is low. Moreover, this rate is much lower for women. The PPVs of different stress methods are similar. Age, presence of diabetes, and MHR ratio are independent predictors for true positive results of SPECT-MPI.

Graphical Abstract

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Safety of Levosimendan in Pediatric Patients: An Up-to-Date Systematic Review

BACKGROUND

The potential risks associated with the use of levosimendan in the pediatric population has not been systematically evaluated. This study aimed to review the available evidence regarding the safety of this treatment.

METHODS

Bio Med Central, PubMed, Embase, and the Cochrane Central Register of clinical trials were searched for studies describing levosimendan administration in the pediatric population in any setting. Relevant studies were independently screened, selected, and their data extracted by two investigators. The authors excluded: reviews, meta-analyses, as well as basic research and trials involving patients >18 years old. The primary outcome was the number and the type of adverse side effects reported during levosimendan administration.

RESULTS

The updated systematic review included 48 studies, enrolling a total of 1,271 pediatric patients who received levosimendan as treatment (790 patients in the 11 studies that reported side effects). The primary adverse effects of levosimendan administration were hypotension and cardiac arrhythmias, particularly tachycardia. Hypotension occurred in approximately 28.9% of patients, while arrhythmia occurred in about 12.3% of patients. Meta analysis of RCTs revealed a rate of all-cause mortality of 2.0% (8 out of 385) in the levosimendan group compared to 3.9% (15 out of 378) in the control group (dobutamine, milrinone or placebo) (risk ratio [RR] = 0.55; 95% confidence interval [CI] = 0.25-1.21; P = 0.14; I2 = 0%) CONCLUSIONS: Hypotension and cardiac arrhythmia are the most reported side effects of levosimendan in pediatric patients. However, adverse events remain underreported, especially in randomized trials.

Hemofiltration Improves Blood Perfusate Conditions Leading to Improved Ex Situ Heart Perfusion

The aim was to optimize the perfusate composition by including a hemofiltrator to the PhysioHeartplatform for ex situ heart perfusion of porcine slaughterhouse hearts. Fourteen hearts were harvested from Dutch Landrace pigs and slaughtered for human consumption. All hearts were preserved for 4 hours using static cold storage before reperfusion for 4 hours on the PhysioHeart platform. Seven hearts were assigned to the hemofiltration group, where a hemofiltrator was added to the perfusion circuit, while the control group did not receive hemofiltration. In the hemofiltration group, the perfusion fluid was filtrated for 1 hour with a flow of 1 L/hour before reperfusion. After mounting the heart, hemofiltration was maintained at 1 L/hour, and cardiac function and blood samples were analyzed at multiple time points. Preserved cardiac function was defined as a cardiac output >3.0 L/min with a mean aortic pressure >60 mm Hg and a left atrial pressure <15 mm Hg. Hemofiltration resulted in a significantly reduced potassium concentration at all time points ( p < 0.001), while sodium levels remained at baseline values ( p < 0.004). Furthermore, creatinine and ammonia levels decreased over time. Functional assessment demonstrated a reduced left atrial pressure ( p < 0.04) and a reduction of the required dobutamine dose to support myocardial function ( p < 0.003) in the hemofiltration group. Preserved cardiac function did not differ between groups. Hemofiltration results in an improved biochemical composition of the whole blood perfusate and preserves cardiac function better during normothermic perfusion based on a reduced left atrial pressure (LAP) and dobutamine requirement to support function.

Anesthetic management of children with medically refractory pulmonary hypertension undergoing surgical Potts shunt

INTRODUCTION

Pulmonary hypertension in children is associated with high rates of adverse events under anesthesia. In children who have failed medical therapy, a posttricuspid shunt such as a Potts shunt can offload the right ventricle and possibly delay or replace the need for lung transplantation. Intraoperative management of this procedure, during which an anastomosis between the pulmonary artery and the descending aorta is created, is complex and requires a deep understanding of the pathophysiology of acute and chronic right ventricular failure. This retrospective case review describes the intraoperative management of children undergoing surgical creation of a Potts shunt at a single center.

METHODS

A retrospective case review of all patients under the age of 18 who underwent Potts shunt between April 2013 and June 2022. Medical records were examined, and clinical data of demographics, intraoperative vital signs, anesthetic management, and postoperative outcomes were extracted.

RESULTS

Twenty-nine children with medically refractory pulmonary hypertension underwent surgical Potts shunts with a median age of 12 years (range 4 months to 17.4 years). Nineteen Potts shunts (65%) were placed via thoracotomy and 10 (35%) were placed via median sternotomy with use of cardiopulmonary bypass. Ketamine was the most frequently utilized induction agent (17 out of 29, 59%), and the majority of patients were initiated on vasopressin prior to intubation (20 out of 29, 69%). Additional inotropic support with epinephrine (45%), milrinone (28%), norepinephrine (17%), and dobutamine (14%) was used prior to shunt placement. Following opening of the Potts shunt, hemodynamic support was continued with vasopressin (66%), epinephrine (62%), milrinone (59%), dobutamine (14%), and norepinephrine (10%). Major intraoperative complications included severe hypoxemia (21 out of 29, 72%) and hypotension requiring boluses of epinephrine (10 out of 29, 34.5%) but no patient suffered intraoperative cardiac arrest. There were four in-hospital mortalities.

DISCUSSION

A Potts shunt offers another palliative option for children with medically refractory pulmonary hypertension. General anesthesia in these children carries high risk for pulmonary hypertensive crises. Anesthesiologists must understand underlying physiological mechanisms responsble for acute hemodynaic decompensation during acute pulmonary hypertneisve crises. Severe physiological perturbations imposed by thoracic surgery and use of cardiopulmonay bypass can be mitigated by aggresive heodynamic support of ventricle function and maintainence of systemic vascular resistance. Early use of vasopressin, before or immidiately after anesthesia induction, in combination with other inotropes is a useful agent during the perioperative care of thes. Early use of vasopressin during anesthesia induction, and aggressive inotropic support of right ventricular function can help mitigate effects of induction and intubation, single-lung ventilation, and cardiopulmonary bypass.

CONCLUSIONS

Our single center expereince shows that the Potts shunt surgery, despite high short-term mortaility, may offer another option for palliation in children with medically refractory pulmonary hypertension.

Donor noradrenaline use is associated with better allograft survival in recipients of pancreas transplantation

INTRODUCTION

Outcomes following pancreas transplantation are suboptimal and better donor selection is required to improve this. Vasoactive drugs (VaD) are commonly used to correct the abnormal haemodynamics of organ donors in intensive care units. VaDs can differentially affect insulin secretion positively (dobutamine) or negatively (noradrenaline). The hypothesis was that some VaDs might induce beta-cell stress or rest and therefore impact pancreas transplant outcomes. The aim of the study was to assess relationships between VaD use and pancreas transplant graft survival.

METHODS

Data from the UK Transplant Registry on all pancreas transplants performed between 2004 and 2016 with complete follow-up data were included. Univariable- and multivariable-adjusted Cox regression analyses determined risks of graft failure associated with VaD use.

RESULTS

In 2,183 pancreas transplants, VaDs were used in the following numbers of donors: dobutamine 76 (3.5%), dopamine 84 (3.8%), adrenaline 161 (7.4%), noradrenaline 1,589 (72.8%) and vasopressin 1,219 (55.8%). In multivariable models, adjusted for covariates and the co-administration of other VaDs, noradrenaline use (vs non-use) was a strong predictor of better graft survival (hazard ratio [95% confidence interval] 0.77 [0.64-0.94], p = 0.01).

CONCLUSIONS

Noradrenaline use was associated with better graft survival in models adjusted for donor and recipient variables - this may be related to inhibition of pancreatic insulin secretion initiating pancreatic beta-cell 'rest'. Further research is required to replicate these findings and establish whether relationships are causal. Identification of alternative methods of inducing beta-cell rest could be valuable in improving graft outcomes.

Are Potential Differences Influenced by Phenylephrine or Dobutamine?

OBJECTIVES

To investigate the agreement between continuous noninvasive blood pressure measurement with the ClearSight system (cNIBP-CS) and standard intermittent noninvasive blood pressure measurement (iNIBP) in patients with peripheral arterial disease (PAD). Additionally, the influence of vasoactive medication on potential measurement differences was assessed.

DESIGN

A secondary analysis of a randomized controlled trial.

SETTING

At a university hospital.

PARTICIPANTS

Thirty-four patients with PAD undergoing percutaneous transluminal angioplasty of the lower limbs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Continuous noninvasive blood pressures were measured with the "ClearSight" system and compared to standard iNIBPs. Bland-Altman analysis revealed a mean bias of 13 mmHg (±15) between cNIBP-CS and iNIBP, with 95% limits of agreement (LOA) ranging from -17 to 42 mmHg. When comparing both medication groups, a similar mean bias was found for phenylephrine and dobutamine (12 mmHg [±13] and 13 mmHg [±13], respectively).

CONCLUSION

In this study, in patients with PAD, cNIBP-CS showed an underestimation of blood pressure compared to iNIBP in phenylephrine- and dobutamine-treated patients. Compared to previous studies, a larger bias and wider 95% LOA were found.

Stress imaging in patients with a Fontan circulation: A systematic review

INTRODUCTION

The aims of this study were to provide an overview of the cardiac stress response in Fontan patients and of the use, safety and clinical value of stress imaging in Fontan patients.

METHODS

Studies evaluating cardiac function using stress imaging in Fontan patients published up until 12 December 2021 were included in this review.

RESULTS

From 1603 potential studies, 32 studies met the inclusion criteria. In total, stress imaging tests of 728 Fontan patients were included. Cardiac function was most often measured using physical stress (61%), all other studies used dobutamine-induced stress. Stroke volume (SV) increased in most studies (71%), mean SV at rest ranged from 27 mL/m2 to 60 mL/m2 versus 27 mL/m2 to 101 mL/m2 during stress, and increased with an average of 4%. Ejection fraction increased in almost all studies, whereas both end-systolic volume and end-diastolic volume decreased during stress. Higher heart rates were obtained with physical stress (82-180) compared to dobutamine induced stress (73-128). Compared to controls, increases in heartrate and SV were lower and end-diastolic volume decreased abnormally in 75% of reporting studies. No major adverse events were reported. Poorer cardiac stress response was related to decreased exercise capacity and higher risk for long-term (adverse) outcomes in Fontan patients.

DISCUSSION

Cardiac stress response in Fontan patients differs from healthy subjects, reflected by lower increases in heart rate, diminished preload and decreased cardiac output, especially during higher levels of exercise. Stress imaging is safe, however the added clinical value needs to be investigated in more detail.

Successful Treatment of Sepsis-Induced Cardiomyopathy with Intra-Aortic Balloon Pumping: A Case Report and Literature Review

BACKGROUND Sepsis-induced cardiomyopathy is cardiac dysfunction in sepsis that sometimes results in reduced cardiac output. Inotropic agents are recommended in patients with sepsis and cardiac dysfunction. Here, we present a case of sepsis-induced cardiomyopathy that was resistant to inotropes and was successfully treated with intra-aortic balloon pumping (IABP). We also reviewed the literature on similar cases of sepsis-induced cardiomyopathy treated with IABP. CASE REPORT A 40-year-old woman with fever and hypotension was admitted to a university hospital. Laboratory test results showed elevated inflammatory markers and cardiac markers, such as creatinine kinase-MB and troponin T. Echocardiography revealed severe left ventricular hypokinesis, and cardiac monitoring revealed a low cardiac output. The patient received antimicrobials, vasopressors, and dobutamine; however, her circulatory status did not respond to these treatments. IABP was introduced 7 h after admission and dramatically increased her blood pressure and cardiac output, resulting in the reduction of vasopressor and dobutamine doses. The patient survived without any IABP-related complications. The literature review of 11 cases of sepsis-induced cardiomyopathy treated with IABP shows consistent results with the presented case in terms of positive effects of IABP on circulatory status and cardiac function, resulting in a reduction of inotropes. CONCLUSIONS Some sepsis-induced cardiomyopathy cases with reduced left ventricular function may not respond to inotropes. IABP would be a treatment option for these patients because of its positive effects on cardiac and circulatory functions.

Successful echocardiography-guided medical management of severe early post-implant right ventricular failure in a patient with left ventricular assist device support: a case report

BACKGROUND

Post-implant right heart failure (RHF) has been recognized as a crucial prognostic factor in patients receiving left ventricular assist devices (LVADs), and its management has long attracted attention from cardiologists and surgeons.

CASE PRESENTATION

This report described an 18-year-old female with acutely deteriorating heart failure due to dilated cardiomyopathy who underwent paracorporeal pulsatile-flow LVAD and developed early post-implant RHF. At postoperative day (POD) six, she was almost asymptomatic at rest on 2.5 mg/kg/min of dobutamine; however, the echocardiogram, performed as part of the daily postoperative care, revealed a severely enlarged right ventricle with a decompressed left ventricle, implying the development of post-implant RHF. Bolus infusion of saline and reduction of pump flow (6.0 L/min to 3.0 L/min) led to normalization of both ventricular shapes in 30 s, suggesting that RHF could be managed without surgical interventions. Milrinone was started on POD six, followed by sildenafil administration on POD seven. Fluid balance was strictly adjusted under the close observation of daily echocardiograms. Milrinone and dobutamine were discontinued on PODs 18 and 21, respectively. The patient was listed for a heart transplant on POD 40. Despite reduced right ventricular function (right ventricular stroke work index of 182.34 mmHg*ml/m- 2, body surface area 1.5 m2), she was successfully converted to implantable LVAD on POD 44 with no recurrence of post-implant RHF thereafter for four years.

CONCLUSIONS

In post-implant RHF management, early detection, together with proper and prompt medical management, is crucial to avoiding any surgical intervention. Close observation of daily echocardiograms might be helpful in detecting subclinical RHF and is useful for post-implant medical management.

A knowledge graph-based analytical model for mining clinical value of drug stress echocardiography for diagnosis, risk stratification and prognostic evaluation of coronary artery disease

The three major techniques for clinically diagnosing coronary heart disease, including angina associated with myocardial ischemia, are coronary angiography, myocardial perfusion imaging, and drug stress echocardiography. Compared to the first two methods, which are invasive or involve the use of radionuclides, drug stress echocardiography is increasingly used in clinical practice due to its non-invasive, low-risk, and controllable nature, and wide applicability. We developed a novel methodology to demonstrate knowledge graph-based efficacy analysis of drug stress echocardiography as a complement to traditional meta-analysis. By measuring coronary flow reserve (CFR), we discovered that regional ventricular wall abnormalities (RVWA) and drug-loaded cardiac ultrasound can be used to detect coronary artery disease. Additionally, drug-loaded cardiac ultrasound can be used to identify areas of cardiac ischemia, stratify risks, and determine prognosis. Furthermore, adenosine stress echocardiography(ASE) can determine atypical symptoms of coronary heart disease with associated cardiac events through CFR and related quantitative indices for risk stratification. Using a knowledge graph-based approach, we investigated the positive and negative effects of three drugs - Dipyridamole, Dobutamine, and Adenosine - for coronary artery disease analysis. Our findings show that Adenosine has the highest positive effect and the lowest negative effect among the three drugs. Due to its minimal and controlled side effects, and high sensitivity for diagnosing coronary microcirculation disorders and multiple lesions, adenosine is frequently used in clinical practice.

The use of peripherally inserted central catheter reduced the incidence of phlebitis in heart failure patients: A randomized trial

BACKGROUND

During decompensated heart failure, the use of intravenous inotropes can be necessary. With peripheral venous access, prolonged inotrope infusion can cause phlebitis. However, traditional central venous catheters have possible complications. Peripherally inserted central catheters (PICCs) may be an alternative to traditional catheters.

AIM

Our objective was to compare the incidence of phlebitis between patients with PICC and those with peripheral venous access catheter indwelling.

METHODS

In a randomized clinical trial, the patients were randomized to PICC and control groups, with 40 patients in each group. The inclusion criteria were hospitalized patients with advanced heart failure, ejection fraction of <0.45, and platelet count of >50,000/mm3 and current use of continuous intravenous infusion of dobutamine. The patients were randomly assigned to receive a PICC or keep their peripheral venous access. The primary end point was the occurrence of phlebitis.

RESULTS

The PICC and control groups included 40 patients each. The median age was 61.5 years; ejection fraction, 0.24; and dobutamine dose, 7.73 µg/(kg min). Phlebitis occurred in 1 patient (2.5%) in the PICC group and in 38 patients (95.0%) in the control group, with an odds ratio of 0.10% (95% confidence interval: 0.01%-1.60%, p < 0.001).

CONCLUSION

In conclusion, in severe heart failure patients who received intravenous dobutamine, PICC use reduced the incidence of phlebitis when compared to patients with peripheral venous access. Therefore, the PICC use should considered over peripheral venous access for prolonged intravenous therapy in heart failure patients.

Preoperative Levosimendan Administration in Heart Transplant Patients with Severe Hepatic and Renal Impairment: A Retrospective Study

BACKGROUND

The cardio-renal syndrome and hepatic impairment play a critical role in end-stage heart failure (HF). Levosimendan is an effective inotropic agent used to maintain cardiac output similar to classic cardiotonic like dobutamine/dopamine. This current research aims to investigate the clinical outcomes of levosimendan and dobutamine/dopamine in Chinese heart transplant awaiting patients with severe hepatic or renal impairment.

METHODS

We performed a retrospective analysis of 568 heart transplant awaiting individuals with severe hepatic or renal impairment who treated with levosimendan or dobutamine/dopamine in our institution between January 2015 and December 2020. Univariate Cox proportional hazard models and Kaplan-Meier survival curves were applied. The primary endpoint was defined as death included inhospital mortality and the mortality at 30 days, 90 days, 180 days and 1 year after heart transplantation.

RESULTS

There were no significant differences in mortality rate at 30, 90, 180 days and 1 years after heart transplantation between the levosimendan and non-levosimendan groups, or between subgroups of patients with severe hepatic impairment or renal impairment. The results were consistent before and after propensity score matching.

CONCLUSIONS

In the population with advanced heart failure awaiting heart transplantation, levosimendan did not increase short- or long-term mortality rates after surgery compared to dobutamine/dopamine, regardless of their hepatic or renal function. Severe hepatic or renal impairment were not necessarily considered a contraindication for levosimendan in these patients.

Efficacy of Co-Medications in Patients with Alcoholic Liver Disease

BACKGROUND

Alcoholic liver disease (ALD) is still increasing and leads to acute liver injury but also liver cirrhosis and subsequent complications such as liver failure or hepatocellular carcinoma (HCC). As most patients fail to achieve alcohol abstinence, it is essential to identify alternative treatment options in order to improve the outcome of ALD patients.

METHODS

Evaluating two large cohorts of patients with ALD from the USA and Korea with a total of 12,006 patients, we investigated the effect on survival of aspirin, metformin, metoprolol, dopamine, and dobutamine drugs in patients with ALD between 2000 and 2020. Patient data were obtained through the "The Observational Health Data Sciences and Informatics consortium," an open-source, multi-stakeholder, and interdisciplinary collaborative effort.

RESULTS

The use of aspirin (p = 0.000, p = 0.000), metoprolol (p = 0.002, p = 0.000), and metformin (p = 0.000, p = 0.000) confers a survival benefit for both AUSOM- and NY-treated cohorts. Need of catecholamines dobutamine (p = 0.000, p = 0.000) and dopamine (p = 0.000, p = 0.000) was strongly indicative of poor survival. β-Blocker treatment with metoprolol (p = 0.128, p = 0.196) or carvedilol (p = 0.520, p = 0.679) was not shown to be protective in any of the female subgroups.

CONCLUSION

Overall, our data fill a large gap in long-term, real-world data on patients with ALD, confirming an impact of metformin, acetylsalicylic acid, and β-blockers on ALD patient's survival. However, gender and ethnic background lead to diverse efficacy in those patients.

Evaluation of blood pressure response during dobutamine stress echocardiography in patients without cardiovascular diseases

Dobutamine stress echocardiography (DSE) is a diagnostic tool for determining coronary artery disease. Considering hypotension and hypertension as important complications of DSE, we aimed to evaluate the blood pressure (BP) responses during DSE. Patients without known cardiovascular diseases who underwent DSE were included. We excluded patients who had hypertension, diabetes mellitus, a known history of cardiovascular diseases, and those taking vasoactive medications. Systolic (SBP) and diastolic (DBP) blood pressure were recorded at baseline and peak stress. We included 688 patients with an age of 57.9 ± 12.01 years. During DSE, SBP (+19.72 ± 26.51 mm Hg, p < 0.001), DBP (+5.52 ± 17.35 mm Hg, p < 0.001), and HR (+54.05 ± 22.45 bpm, p < 0.001) significantly increased from baseline to peak stress. The normal cut-off value was measured between 101-210 mm Hg for SBP and 50-121 mm Hg for DBP. According to this normal cutoff, 11 (1.3%) and 30 (4.4%) patients had hypotensive and hypertensive SBP and 15 (2.2%) and 21 (3.1%) patients had hypotensive and hypertensive DBP, respectively. The hypotensive response was correlated with baseline SBP (r = 0.6, p = 0.001) and atropine (r = -2.18, p = 0.043), and the hypertensive response was correlated with baseline SBP (r = 0.048, p < 0.001). Baseline BP and atropine consumption were the independent variables associated with the outside-the-normal range of blood pressure responses.

Errata: Patients with Moderate Non-Culprit Coronary Lesions of Recent Acute Coronary Syndrome: A Comparison of Fractional Flow Reserve and Dobutamine Stress Echocardiography

An error appeared in the article entitled "Patients with Moderate Non-Culprit Coronary Lesions of Recent Acute Coronary Syndrome: A Comparison of Fractional Flow Reserve and Dobutamine Stress Echocardiography" by Abdelkrim Ahres, Balázs Jablonkai, Ágnes Schrancz, Zsuzsanna Balogh, Andrea Kenessey, Tamás Baranyai, Ágnes Őze, Zsolt Szigeti, Gábor Rubóczky, Béla Nagybaczoni, Astrid Apor, Judit Simon, Bálint Szilveszter, Márton Kolossváry, Béla Merkely, Pál Maurovich-Horvat, and Péter Andrássy (Vol. 62 No.5, 952-961, 2021). The affiliation of the first author on page 952 should be replaced by the following.

Incremental value of 18F-FDG cardiac PET imaging over dobutamine stress echocardiography in predicting myocardial ischemia in patients with suspected coronary artery disease

BACKGROUND

To assess the incremental value of 18F-fluorodeoxyglucose (FDG) cardiac positron emission tomography (PET) over dobutamine stress echocardiography (DSE) in predicting myocardial ischemia in patients with suspected coronary artery disease (CAD).

METHODS

Forty-one patients with suspected CAD underwent within 7 days apart rest-stress cardiac PET with 82Rb and DSE followed by cardiac 18F-FDG PET imaging. 18F-FDG images were scored on a 0 (no discernible uptake) to 2 (intense uptake) scale. Logistic regression analysis was performed to identify predictors of stress-induced ischemia. The incremental value of 18F-FDG PET over DSE in detecting ischemia at 82Rb PET cardiac imaging was assessed by the likelihood ratio chi-square and net reclassification index.

RESULTS

On 82Rb-PET imaging, myocardial ischemia (ischemic total perfusion defect ≥ 5%) was detected in 20 (49%) patients. Inducible ischemia was found in 22 (54%) patients on DSE (biphasic or worsening response pattern in ≥ 1 segment) and in 21 (51%) patients on 18F-FDG PET (uptake score of 2 in ≥ 1 segment). 18F-FDG PET resulted as statistically significant predictor of ischemia on 82Rb-PET. The addition of 18F-FDG PET to DSE increased the likelihood of ischemia on 82Rb-PET (P < .05). 18F-FDG PET was able to reclassify the probability of stress-induced myocardial ischemia on both patient and vessel analyses.

CONCLUSION

18F-FDG PET performed after dobutamine stress test may provide incremental value to DSE in the evaluation of myocardial ischemia. These results suggest that stress-induced myocardial ischemia can be imaged directly using 18F-FDG PET after dobutamine stress test.

Prognostic implication of myocardial perfusion and contractile reserve in end-stage renal disease: A direct comparison of myocardial perfusion scintigraphy and dobutamine stress echocardiography

BACKGROUND

We aimed to compare the prognostic value of myocardial perfusion scintigraphy (MPS) and dobutamine stress echocardiography (DSE) in patients with end-stage renal disease (ESRD) without known coronary artery disease.

METHODS

Two-hundred twenty-nine ESRD patients who applied for kidney transplantation at our centre were prospectively evaluated by MPS and DSE. The primary endpoint was a composite of myocardial infarction (MI) or all-cause mortality. The secondary endpoint included MI or coronary revascularization (CR) not triggered by MPS or DSE at baseline.

RESULTS

MPS detected reversible ischemia in 31 patients (13.5%) and fixed perfusion defects in 13 (5.7%) patients. DSE discovered stress-induced wall motion abnormalities (WMAs) in 28 (12.2%) and at rest in 18 (7.9%) patients. MPS and DSE results agreed in 85.6% regarding reversible defects (κ = 0.358; P < .001) and in 90.8% regarding fixed defects (κ = 0.275; P < .001). Coronary angiography detected relevant stenosis > 50% in only 15 of 38 patients (39.5%) with pathological findings in MPS and/or DSE. At a median follow-up of 8 years and 10 months, the primary endpoint occurred in 70 patients (30.6%) and the secondary endpoint in 24 patients (10.5%). The adjusted Cox hazard ratios (HRs) for the primary endpoint were 1.77 (95% CI 1.02-3.08; P = .043) for perfusion defects in MPS and 1.36 (95% CI 0.78-2.37; P = ns) for WMA in DSE. The secondary endpoint was significantly correlated with the findings of both modalities, MPS (HR 3.21; 95% CI 1.35-7.61; P = .008) and DSE (HR 2.67; 95% CI 1.15-6.20; P = .022).

CONCLUSION

Perfusion defects in MPS are a stronger determinant of all-cause mortality, MI and the need for future CR compared with WMAs in DSE. Given the complementary functional information provided by MPS vs DSE, results are sometimes contradictory, which may indicate differences in the underlying pathophysiology.

French Scorpionism (Mainland and Oversea Territories): Narrative Review of Scorpion Species, Scorpion Venom, and Envenoming Management

Sixty-seven scorpion species have been described in France and its territories, where they have been found to be heterogeneously distributed. Indeed, only one species can be found on Réunion Island, while 38 species exist in French Guiana. The number of stings is also heterogenous, with up to 90 stings per 100,000 inhabitants occurring annually. Scorpion species can frequently be determined through simple visual factors, including species of medical importance (i.e., Buthus, Centruroides and Tityus). Scorpion venom is composed of local enzymes and peptides with a cysteine-stabilized α/β motif (NaTxs, Ktxs, Calcines), which allow for venom diffusion and the prey's incapacitation, respectively. Harmful scorpion species are limited to Centruroides pococki in the French West Indies, which can induce severe envenoming, and the Tityus obscurus and Tityus silvestris in French Guiana, which can cause fatalities in children and can induce severe envenoming, respectively. Envenomation by one of these scorpions requires hospital monitoring as long as systemic symptoms persist. Typical management includes the use of a lidocaine patch, pain killers, and local antiseptic. In the case of heart failure, the use of dobutamine can improve survival, and pregnant women must consult an obstetrician because of the elevated risk of preterm birth or stillbirth. France does not have scorpion antivenom, as scorpion stings are generally not fatal.

Combination Immunosuppressive Therapy for Giant Cell Myocarditis

A 60-year-old woman with a history of hypothyroidism was referred to our hospital for shortness of breath and a left ventricular ejection fraction (LVEF) of 13%, which required continuous dobutamine injection with intra-aortic balloon pump support. An endomyocardial biopsy obtained from the right ventricle revealed an infiltration of giant cells and eosinophils, indicating giant cell myocarditis. In addition to heart failure treatment, combined immunotherapy with steroids, tacrolimus, and intravenous immunoglobulin was administered. Transthoracic echocardiography demonstrated a dramatic improvement in the LVEF after this therapy, and the patient was discharged home without symptoms on day 72.

Neurogenic stunned myocardium resulting from surgical brainstem handling during resection of paediatric recurrent medulloblastoma-a possible brain heart interaction

BACKGROUND

Neurogenic stunned myocardium (NSM) is characterised by an acute onset cardiac dysfunction following an acute neurological insult which mimics acute coronary syndrome.

CASE DETAILS

A 12-year-old male child was admitted to the neuro-intensive care unit (NICU) following midline suboccipital craniotomy and resection of recurrent medulloblastoma. Postoperatively, in NICU, he developed tachycardia and hypotension, which was unresponsive to fluid challenge requiring norepinephrine infusion. Intraoperatively, during tumour resection from the dorsal medulla, episodes of hypertension and bradycardia were observed. Intraoperative blood loss was adequately managed with a stable hemodynamic profile without postoperative anaemia. An electrocardiogram showed sinus tachycardia with T wave inversion, and blood investigation revealed elevated cardiac troponin T levels. Point of care ultrasound (POCUS) of heart and lung showed features of NSM. Infusion dobutamine was added to achieve a target mean arterial pressure of 65 mm Hg with concomitant furosemide infusion and fluid restriction. Daily POCUS assessment of cardiac contractility and volume status was done. The patient was weaned from vasoactive drugs and ventilator following improvement of cardiac function and was discharged from NICU after 17 days.

CONCLUSION

NSM results from the excessive release of catecholamines following stimulation of trigger zones in the brain. To date, a handful of cases of pediatric NSM following primary brain tumour are reported where hydrocephalus resulted in trigger zone activation. In this presented case, direct brain stem stimulation during tumour resection might have triggered NSM. Irrespective of the cause, timely diagnosis and execution of supportive management in our patient resulted in a positive outcome.

Adverse right ventricular remodelling, function, and stress responses in obesity: insights from cardiovascular magnetic resonance

AIMS

We aimed to determine the effect of increasing body weight upon right ventricular (RV) volumes, energetics, systolic function, and stress responses using cardiovascular magnetic resonance (CMR).

METHODS AND RESULTS

We first determined the effects of World Health Organization class III obesity [body mass index (BMI) > 40 kg/m2, n = 54] vs. healthy weight (BMI < 25 kg/m2, n = 49) upon RV volumes, energetics and systolic function using CMR. In less severe obesity (BMI 35 ± 5 kg/m2, n = 18) and healthy weight controls (BMI 21 ± 1 kg/m2, n = 9), we next performed CMR before and during dobutamine to evaluate RV stress response. A subgroup undergoing bariatric surgery (n = 37) were rescanned at median 1 year to determine the effects of weight loss. When compared with healthy weight, class III obesity was associated with adverse RV remodelling (17% RV end-diastolic volume increase, P < 0.0001), impaired cardiac energetics (19% phosphocreatine to adenosine triphosphate ratio reduction, P < 0.001), and reduction in RV ejection fraction (by 3%, P = 0.01), which was related to impaired energetics (R = 0.3, P = 0.04). Participants with less severe obesity had impaired RV diastolic filling at rest and blunted RV systolic and diastolic responses to dobutamine compared with healthy weight. Surgical weight loss (34 ± 15 kg weight loss) was associated with improvement in RV end-diastolic volume (by 8%, P = 0.006) and systolic function (by 2%, P = 0.03).

CONCLUSION

Increasing body weight is associated with significant alterations in RV volumes, energetic, systolic function, and stress responses. Adverse RV modelling is mitigated with weight loss. Randomized trials are needed to determine whether intentional weight loss improves symptoms and outcomes in patients with obesity and heart failure.

The Role of Stress Echocardiography in Valvular Heart Disease

Purpose of Review

Stress echocardiography is recommended in valvular heart disease when there is a mismatch between resting transthoracic echocardiography findings and symptoms during activities of daily living. We describe the current methodology and the evidence supporting these applications.

Recent Findings

The comprehensive stress echo assessment includes valve function (gradients and regurgitation), left ventricular global systolic and diastolic function, left atrial volume, pulmonary congestion, pulmonary arterial pressure, and right ventricular function, integrated with blood pressure response with cuff sphygmomanometer, chronotropic reserve with heart rate, and symptoms.

Summary

Recent guidelines recommend the evaluation of asymptomatic severe or symptomatic non-severe mitral regurgitation or stenosis with exercise stress and suspected low-flow, low-gradient severe aortic stenosis with reduced ejection fraction with low dose (up to 20 mcg, without atropine) dobutamine stress. Prospective, large-scale studies based on a comprehensive protocol (ABCDE +) capturing the multiplicity of clinical phenotypes are needed to support stress echo-driven treatment strategies.

Dobutamine stress PET/CT for assessment of hemodynamic significance of coronary myocardial bridges

Myocardial bridges are common and often benign, but can cause hemodynamically significant obstruction of blood flow with stress. Dobutamine stress positron emission tomography/computed tomography (PET/CT) is a powerful tool for non-invasively assessing for ischemia. We present a case of using dobutamine stress PET/CT to determine the significance of a myocardial bridge.

Diagnostic performance of dobutamine stress echocardiography: A South African experience

Dobutamine stress echocardiography (DSE) is a well-established modality for the diagnosis of coronary artery disease, but there are no reported diagnostic data in southern Africa. Objectives. To compare the safety, sensitivity and specificity of a South African (SA) DSE programme with larger, international series. Methods. All patients undergoing DSE from 2019 to 2021 at a single SA centre were included. A new wall motion abnormality (≥2 segments) signified inducible ischaemia. Results. A total of 106 patients (mean (standard deviation) age 61 (11) years, 68% male) were analysed. Six patients (6%) experienced chest pain during DSE and 4 (4%) developed an atrial arrhythmia. The sensitivity and specificity for epicardial coronary stenosis were 77% and 74%, respectively, changing to 82% and 72% when excluding those who had previous coronary artery bypass surgery. Conclusion. The sensitivity, specificity and safety of an SA DSE programme were comparable to international series. A DSE programme is feasible in a resource-constrained environment.

Severe Aortic Stenosis: More Than an Imaging Diagnosis

The definition of severe aortic stenosis has undergone significant change casting a wider net to avoid missing patients who could benefit from valve replacement. The presence or absence of symptoms remains the key decision-making element; however, individuals presently undergoing evaluation are older, more likely asymptomatic, and have lower gradients. Due to numerous potential measurement errors, attention to detail when performing diagnostic testing and understanding their limitations are necessary to render appropriate treatment. Exercise testing adds useful information for individuals with severe aortic stenosis felt to be asymptomatic. Dobutamine echocardiography, in low flow-low gradient aortic stenosis, distinguishes between a myopathic and valvular cause of left ventricular dysfunction. Evaluation of patients when normotensive minimizes measurement errors. The amount of aortic valve calcification adds useful information when the degree of aortic stenosis is uncertain. A good history and physical integrated with high-quality imaging data allows for appropriate clinical treatment decisions for patients with aortic stenosis. The goal is simultaneously to provide aortic valve replacement for patients in need while avoiding overdiagnosis and performance of unnecessary procedures.

Non-invasive capnodynamic mixed venous oxygen saturation during major changes in oxygen delivery

Mixed venous oxygen saturation (SvO₂) is an important variable in anesthesia and intensive care but currently requires pulmonary artery catheterization. Recently, non-invasive determination of SvO₂ (Capno-SvO₂) using capnodynamics has shown good agreement against CO-oximetry in an animal model of modest hemodynamic changes. The purpose of the current study was to validate Capno-SvO₂ against CO-oximetry during major alterations in oxygen delivery. Furthermore, evaluating fiberoptic SvO₂ for its response to the same challenges. Eleven mechanically ventilated pigs were exposed to oxygen delivery changes: increased inhaled oxygen concentration, hemorrhage, crystalloid and blood transfusion, preload reduction and dobutamine infusion. Capno-SvO₂ and fiberoptic SvO₂ recordings were made in parallel with CO-oximetry. Respiratory quotient, needed for capnodynamic SvO₂, was measured by analysis of mixed expired gases. Agreement of absolute values between CO-oximetry and Capno-SvO₂ and fiberoptic SvO₂ respectively, was assessed using Bland–Altman plots. Ability of Capno- SvO₂ and fiberoptic SvO₂ to detect change compared to CO-oximetry was assessed using concordance analysis. The interventions caused significant hemodynamic variations. Bias between Capno-SvO₂ and CO-oximetry was + 3% points (95% limits of agreements – 7 to + 13). Bias between fiberoptic SvO₂ and CO-oximetry was + 1% point, (95% limits of agreements − 7 to + 9). Concordance rate for Capno-SvO₂ and fiberoptic SvO₂ vs. CO-oximetry was 98% and 93%, respectively. Capno-SvO₂ generates absolute values close to CO-oximetry. The performance of Capno-SvO₂ vs. CO-oximetry was comparable to the performance of fiberoptic SvO₂ vs. CO-oximetry. Capno-SvO₂ appears to be a promising tool for non-invasive SvO₂ monitoring.

Comparison of coronary flow reserve feasibility in different stress echocardiography protocols: dobutamine, dipyridamole, exercise, and rapid pacing

INTRODUCTION

Coronary Flow Velocity Reserve (CFVR) assessment may improve diagnostic and prognostic value of stress echocardiography (SE).

OBJECTIVES

To compare the feasibility of CFVR assessment in the left anterior descending (LAD) artery in four types of SE: dobutamine (DOB), dipyridamole (DIP), rapid pacing (PAC) and bicycle exercise (EXE).

PATIENTS AND METHODS

We subjected 369 patients, mean (SD) age: 67 (11) to SE with DOB (n = 230), DIP (n = 73), PAC (n = 22) or EXE (n = 44). CFVR was measured as the ratio of peak diastolic coronary flow velocity (CFV) during exercise, pharmacological stress or pacing and peak diastolic CFV at rest in distal or mid LAD.

RESULTS

The feasibility was excellent during PAC (100%), DOB (95%) and DIP (95%) and lower during EXE (73%, P < 0.01 vs other groups). In multivariable analysis the EXE protocol was a predictor of LAD flow loss during SE, with OR = 7.89 (95% CI 2.17 - 31.33), P = 0.002. CFVR was lower with PAC 1.7 (1.4 - 2.0) as compared to DOB 2.1 (1.7 - 2.5), DIP 2.1 (1.8 - 2.5) and EXE 2.0 (1.7 - 2.3), P < 0.05 for all.

CONCLUSIONS

CFVR in LAD can be obtained during all forms of SE, but the feasibility is significantly higher with PAC and pharmacological tests as compared to EXE, which was identified in our study as the independent predictor of the loss of LAD flow recording at the peak of stress test.

Dobutamine stress cardiac MRI is safe and feasible in pediatric patients with anomalous aortic origin of a coronary artery (AAOCA)

BACKGROUND

Risk stratification in anomalous aortic origin of a coronary artery (AAOCA) is challenged by the lack of a reliable method to detect myocardial ischemia. We prospectively studied the safety and feasibility of Dobutamine stress-cardiac magnetic resonance (DSCMR), a test with excellent performance in adults, in pediatric patients with AAOCA.

METHODS

Consecutive DSCMR from 06/2014-12/2019 in patients≤20 years old with AAOCA were included. Hemodynamic response and major/minor events were recorded. Image quality and spatial/temporal resolution were evaluated. Rest and stress first-pass perfusion and wall motion abnormalities (WMA) were assessed. Inter-observer agreement was assessed using kappa coefficient.

RESULTS

A total of 224 DSCMR were performed in 182 patients with AAOCA at a median age of 14 years (IQR 12, 16) and median weight of 58.0 kg (IQR 43.3, 73.0). Examinations were completed in 221/224 (98.9%), all studies were diagnostic. Heart rate and blood pressure increased significantly from baseline (p < 0.001). No patient had major events and 28 (12.5%) had minor events. Inducible hypoperfusion was noted in 31/221 (14%), associated with WMA in 13/31 (42%). Inter-observer agreement for inducible hypoperfusion was very good (Κ = 0.87). Asymptomatic patients with inducible hypoperfusion are considered high-risk and those with a negative test are of standard risk.

CONCLUSIONS

DSCMR is feasible in pediatric patients with AAOCA to assess for inducible hypoperfusion and WMA. It can be performed safely with low incidence of major/minor events. Thus, DSCMR is potentially a valuable test for detection of myocardial ischemia and helpful in the management of this patient population.

Comparison of myocardial blood flow and flow reserve with dobutamine and dipyridamole stress using rubidium-82 positron emission tomography

BACKGROUND

The objective of this study was to compare the hyperemic myocardial blood flow (MBF) and myocardial flow reserve (MFR) obtained with dobutamine to those of dipyridamole in patients referred for myocardial perfusion imaging (MPI) using 82Rb positron emission tomography.

METHODS

One hundred and fifty-six patients who underwent a 82Rb PET MPI study with dobutamine stress were included. A matching cohort of patients who underwent a 82Rb PET MPI study with dipyridamole stress was created, accounting for sex, age, history of coronary artery disease (CAD), prior revascularization, CAD risk factors, body mass index, and MPI interpretation.

RESULTS

Global rest MBF (median [interquartile range] 0.84 [0.64-1.00] vs 0.69 [0.59-0.85]), stress MBF (2.36 [1.73-3.08] vs 1.66 [1.25-2.06]), MFR (2.75 [2.19-3.64] vs 2.29 [1.78-2.84]), and corrected MFR (2.85 [2.14-3.64] vs 2.20 [1.65-2.75]) were all significantly higher (P < 0.0001) in the dobutamine cohort compared to the dipyridamole cohort.

CONCLUSION

The results of this study suggest that dobutamine produces higher MBF compared to dipyridamole in a representative population referred to nuclear cardiology laboratories.

Aortic acceleration as a noninvasive index of left ventricular contractility in the mouse

The maximum value of the first derivative of the invasively measured left ventricular (LV) pressure (+ dP/dtmax or P') is often used to quantify LV contractility, which in mice is limited to a single terminal study. Thus, determination of P' in mouse longitudinal/serial studies requires a group of mice at each desired time point resulting in "pseudo" serial measurements. Alternatively, a noninvasive surrogate for P' will allow for repeated measurements on the same group of mice, thereby minimizing physiological variability and requiring fewer animals. In this study we evaluated aortic acceleration and other parameters of aortic flow velocity as noninvasive indices of LV contractility in mice. We simultaneously measured LV pressure invasively with an intravascular pressure catheter and aortic flow velocity noninvasively with a pulsed Doppler probe in mice, at baseline and after the administration of the positive inotrope, dobutamine. Regression analysis of P' versus peak aortic velocity (vp), peak velocity squared/rise time (vp2/T), peak (+ dvp/dt or v'p) and mean (+ dvm/dt or v'm) aortic acceleration showed a high degree of association (P' versus: vp, r2 = 0.77; vp2/T, r2 = 0.86; v'p, r2 = 0.80; and v'm, r2 = 0.89). The results suggest that mean or peak aortic acceleration or the other parameters may be used as a noninvasive index of LV contractility.

Quantitative blood flow evaluation of vasodilation-stress compared with dobutamine-stress in patients with end-stage liver disease using 82Rb PET/CT

BACKGROUND

Our aim was to determine if end-stage liver disease (ESLD) is associated with an attenuated response to vasodilator-stress or dobutamine-stress using 82Rb-PET MPI with blood flow quantification.

METHODS AND RESULTS

Pre-liver transplant patients who had a normal dipyridamole-stress (n = 27) or dobutamine-stress (n = 26) 82Rb PET/CT MPI study with no identifiable coronary artery calcium were identified retrospectively and compared to a prospectively identified low-risk of liver disease dipyridamole-stress control group (n = 20). The dipyridamole-stress liver disease group had a lower myocardial flow reserve (MFR) (1.89 ± 0.79) than the control group (2.79 ± 0.96, P < .05). The dobutamine-stress group had a higher MFR than both other groups (3.69 ± 1.49, P < .05). A moderate negative correlation between MELD score and MFR was demonstrated for the dipyridamole-stress liver disease group (r = - 0.473, P < .05). This correlation was not observed for the dobutamine-stress liver disease group (r = - 0.253, P = .21). The liver failure group as a whole (n = 53) had a higher resting myocardial blood flow (0.97 ± 0.33 mL/min/g) than the control group (0.82 ± 0.26, P < .05).

CONCLUSION

Dipyridamole demonstrates an attenuated vasodilatory response in ESLD patients compared to a non-ESLD control group related to higher resting blood flow and comparatively reduced stress blood flow. Dobutamine does not demonstrate this effect implying it may be the preferred pharmacologic MPI stress agent for ESLD patients.

[Dobutamine speckle tracking imaging for evaluation of microvascular dysfunction in a patient with exertion dyspnea]

Microcirculatory dysfunction despite the absence of angiographically obvious significant coronary artery disease may potentially generate symptomatic myocardial ischemia; comprehensive assessment both noninvasive and invasive could prove to be of critical interest. We report the case of a 54-year old patient referred for an exertion dyspnea that proved to be caused by both micro and microvascular dysfunction. We present key elements for diagnosis, functional evaluation and management and demonstrate the potential role of speckle tracking imaging in that setting.

SPECKLE TRACKING DOBUTAMINE STRESS ECHOCARDIOGRAPHY DIAGNOSTIC ACCURACY IN PRIMARY CORONARY ARTERIES DISEASE DIAGNOSIS

OBJECTIVE

The aim of the work was to evaluate STE feasibility as DSE visualization method and its accuracy compared to coronary angiography (CAG) in the patients with moderate-tohigh coronary arteries disease (CAD) risk.

PATIENTS AND METHODS

Materials and methods: We prospectively examined 140 pts (84 (60.0%) men) with suspected CAD in order to verify diagnosis and evaluate myocardial viability and coronary reserve.

RESULTS

Results: Mean LV EF was 54.4±15.8%. All pts had normal BP and HR during the test. There were no significant hemodynamics alterations during the test. There were no significant complications during DSE - 15 (12.9%) cases of different relatively low-grade supraventricular and ventricular arrhythmia, mainly transitory without interventions. There were 116 (82.9%) positive DSE results, of which 2 (1.72%) were false-positive. In 2 (8.3%) pts with negative DSE results CAG revealed 1-vessel insignificant (50 - 70%) lesions with developed collaterals (false-negative results). According to DSE and CAG results, 96 (82.3%) pts underwent revascularization interventions - 86 (89.6%) PCI's and (10.4%) CABG surgeries. Sensitivity and specificity of DSE with STE for primary CAD diagnosis according to "golden standard" CAG results were 98.3% and 91.7%, respectively, with identical positive and negative predictive value and very high method overall accuracy (AUC = 0.98) and OR = 627.0 (p<0.0001). Sensitivity and specificity of DSE with STE for defining indications for intervention and revascularization were 97.9% and 91.7%, respectively, with high overall accuracy (AUC = 0.95; OR = 564.0, p<0.0001). Combined quantification of ΔGLS and ΔWMSI for primary CAD diagnosis showed significantly lower sensitivity 86.2% (р=0.0002) and specificity 80.4% (р=0.0064) with significantly lower integral method accuracy (AUC 0.83, р<0.0001).

CONCLUSION

Conclusions: DSE with STE as a visualization method is a safe and optimal method for ischemia diagnosis and myocardial viability and coronary reserve evaluation in the pts with CAD suspicion. Given the lower ΔGLS and ΔWMSI accuracy compared to integral DSE with STE result evaluation, as well as frequent GLS growth in significant amount of patients with definite positive test result, authors recommend evaluating integral test result rather than strain value.

Cardiac metabolic modulation upon low-carbohydrate low-protein ketogenic diet in diabetic rats studied in vivo using hyperpolarized 13 C pyruvate, butyrate and acetoacetate probes

AIM

To investigate the effects of long-term low-carbohydrate low-protein ketogenic diet (KD) on cardiac metabolism and diabetic cardiomyopathy status in lean diabetic Goto-Kakizaki (GK) rats.

MATERIALS AND METHODS

Diabetic GK rats were fed with KD for 62 weeks. Cardiac function and metabolism were assessed using magnetic resonance imaging and ¹³ C magnetic resonance spectroscopy (¹³ C-MRS), at rest and under dobutamine stress. ¹³ C-MRS was performed following injection of hyperpolarized [3-¹³ C]acetoacetate, [1-¹³ C]butyrate or [1-¹³ C]pyruvate to assess ketone body, short-chain fatty acid or glucose utilization, respectively. Protein expression and cardiomyocyte structure were determined via Western blotting and histology, respectively.

RESULTS

KD lowered blood glucose, triglyceride and insulin levels while increasing blood ketone body levels. In KD-fed diabetic rats, myocardial ketone body and glucose oxidation were lower than in chow-fed diabetic rats, while myocardial glycolysis and short-chain fatty acid oxidation were unaltered. Dobutamine stress revealed an increased cardiac preload and reduced cardiac compliance in KD-fed diabetic rats. Dobutamine-induced stimulation of myocardial glycolysis was more enhanced in KD-fed diabetic rats than in chow-fed diabetic rats, which was potentially facilitated via an upregulation in basal expression of proteins involved in glucose transport and glycolysis in the hearts of KD-fed rats. The metabolic profile induced by KD was accompanied by cardiac hypertrophy, a trend for increased myocardial lipid and collagen content, and an increased marker of oxidative stress.

CONCLUSION

KD seems to exacerbate diabetic cardiomyopathy in GK rats, which may be associated with maladaptive cardiac metabolic modulation and lipotoxicity.

Prediction of 14-year cardiovascular outcomes by dobutamine stress 99mTc-tetrofosmin myocardial perfusion SPECT in elderly patients unable to perform exercise testing

BACKGROUND

Dobutamine stress myocardial perfusion imaging (MPI) is a useful alternative for the evaluation of coronary artery disease (CAD) in elderly patients who are unable to perform an exercise stress test. However, data on the long-term prognostic value of stress MPI in elderly patients are lacking. Therefore, this study evaluated the long-term prognostic value of dobutamine stress MPI in elderly patients unable to perform an exercise test.

METHODS

The study population consisted of 247 elderly patients (mean age 71 ± 5 years) who underwent dobutamine stress single-photon emission computed tomography (SPECT) MPI. An abnormal SPECT study was defined as the presence of fixed and/or reversible perfusion defects. A summed stress score (SSS) was obtained to estimate the extent and severity of perfusion defects. End points during follow-up were all-cause mortality, cardiac mortality, and nonfatal myocardial infarction (MI).

RESULTS

During a median follow-up of 14 years (range 12-16), 168 (68%) patients died (all-cause mortality), of which 56 (23%) were due to cardiac causes. Nonfatal MI occurred in 19 (8%) patients. Kaplan-Meier survival curves showed that MPI provided optimal risk stratification in patients with normal and abnormal MPI. Multivariable analysis identified an abnormal MPI as a strong significant predictor of all-cause mortality and cardiac events. A multivariable analysis also revealed that a reversible defect and SSS were strong long-term predictors of cardiac mortality and hard cardiac events.

CONCLUSION

Dobutamine stress 99mTc-tetrofosmin SPECT provides incremental prognostic information for the prediction of long-term cardiovascular outcomes in elderly patients, unable to perform exercise testing. Dobutamine stress MPI is useful in risk classifying elderly patients.