REDISCOVER International Guidelines on the Perioperative Care of Surgical Patients With Borderline-resectable and Locally Advanced Pancreatic Cancer

OBJECTIVE

The REDISCOVER consensus conference aimed at developing and validate guidelines on the perioperative care of patients with borderline resectable (BR-) and locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC).

SUMMARY BACKGROUND DATA

Coupled with improvements in chemotherapy and radiation, the contemporary approach to pancreatic surgery supports resection of BR-PDAC and, to a lesser extent, LA-PDAC. Guidelines outlining the selection and perioperative care for these patients are lacking.

METHODS

The Scottish Intercollegiate Guidelines Network (SIGN) methodology was used to develop the REDISCOVER guidelines and create recommendations. The Delphi approach was used to reach consensus (agreement ≥80%) among experts. Recommendations were approved after a debate and vote among international experts in pancreatic surgery and pancreatic cancer management. A Validation Committee used the AGREE II-GRS tool to assess the methodological quality of the guidelines. Moreover, an independent multidisciplinary advisory group revised the statements to ensure adherence to non-surgical guidelines.

RESULTS

Overall, 34 recommendations were created targeting centralization, training, staging, patient selection for surgery, possibility of surgery in uncommon scenarios, timing of surgery, avoidance of vascular reconstruction, details of vascular resection/reconstruction, arterial divestment, frozen section histology of perivascular tissue, extent of lymphadenectomy, anticoagulation prophylaxis and role of minimally invasive surgery. The level of evidence was however low for 29 of 34 clinical questions. Participants agreed that the most conducive mean to promptly advance our understanding in this field is to establish an international registry addressing this patient population ( https://rediscover.unipi.it/ ).

CONCLUSIONS

The REDISCOVER guidelines provide clinical recommendations pertaining to pancreatectomy with vascular resection for patients with BR- and LA-PDAC, and serve as the basis of a new international registry for this patient population.

Salivary lactate and 8-isoprostaglandin F2α as potential non-invasive biomarkers for monitoring heart failure: a pilot study

Heart failure (HF) is a cardiovascular disease affecting about 26 million people worldwide costing about $100 billons per year. HF activates several compensatory mechanisms and neurohormonal systems, so we hypothesized that the concomitant monitoring of a panel of potential biomarkers related to such conditions might help predicting HF evolution. Saliva analysis by point-of-care devices is expected to become an innovative and powerful monitoring approach since the chemical composition of saliva mirrors that of blood. The aims of this study were (i) to develop an innovative procedure combining MEPS with UHPLC-MS/MS for the simultaneous determination of 8-isoprostaglandin F_2α and cortisol in saliva and (ii) to monitor lactate, uric acid, TNF-α, cortisol, α-amylase and 8-isoprostaglandin F_2α concentrations in stimulated saliva samples collected from 44 HF patients during their hospitalisation due to acute HF. Limit of detection of 10 pg/mL, satisfactory recovery (95–110%), and good intra- and inter-day precisions (RSD ≤ 10%) were obtained for 8-isoprostaglandin F_2α and cortisol. Salivary lactate and 8-isoprostaglandin F_2α were strongly correlated with NT-proBNP. Most patients (about 70%) showed a significant decrease (a factor of 3 at least) of both lactate and 8-isoprostaglandin F_2α levels at discharge, suggesting a relationship between salivary levels and improved clinical conditions during hospitalization.

4180Expression profile of microRNAs in cardiac tissue from pediatric patients with heart failure (HF) supported by Ventricular Assist Device and their involvement in pathophysiological mechanisms of HF

Background

Ventricular Assist Device (VAD) has been increasingly used as bridge to transplantation for the treatment both of adult and pediatric patients with end-stage Heart Failure (HF). Several studies reported that VAD support could affect cardiac molecular mechanisms, including miRNA expression, in HF adult patients. However, little is known about the miRNA profile in pediatric HF patients supported by VAD.

Purpose

Aim of this study was to evaluate the effects of VAD support on expression profile of miRNAs in cardiac tissue from pediatric patients with HF, and to enrich the analysis by an in silico exploration of their potential functions and pathways.

Methods

Cardiac biopsies from HF children collected at the time of VAD implant [8 HF children; 57±33 (mean±SD) months; 2 males; 14.2±13.5 weight; 29±8 LVEF%] and at the time of heart transplantation after 155±33 days of VAD support [5 children; 90±46 months; 4 males; 30±15.8 weight; 38±3.9 LVEF%] were used for profiling miRNA expression by Next Generation Sequencing (NGS). Bioinformatic analyses were performed to identify the differentially expressed miRNAs in cardiac tissues after VAD support, to elucidate their potential functions (Gene Ontology), and to predict their target genes (miRWalk database).

Results

We identified two upregulated miRNAs (miR-29b-1-5p, miR-338-3p) and four downregulated miRNAs (miR-199a-5p, miR-199b-5p, miR-19a-3p, miR-1246) after VAD support. Gene enrichment analysis identified heart development/function, apoptosis and metabolism as main process modulated by the selected miRNAs (Fig A). Moreover, twenty genes were selected as putative miRNA targets involved in the pathophysiology of HF (Fig B).

Conclusion

In summary, the results of the present study suggest that modification of six miRNAs in cardiac tissue from HF children after VAD support may be involved in the regulation of several pathophysiological mechanisms underlying HF, thus providing novel perspectives for future researches.

Determination of volatile organic compounds in exhaled breath of heart failure patients by needle trap micro-extraction coupled with gas chromatography-tandem mass spectrometry

The analytical performances of needle trap micro-extraction (NTME) coupled with gas chromatography-tandem mass spectrometry were evaluated by analyzing a mixture of twenty-two representative breath volatile organic compounds (VOCs) belonging to different chemical classes (i.e. hydrocarbons, ketones, aldehydes, aromatics and sulfurs). NTME is an emerging technique that guarantees detection limits in the pptv range by pre-concentrating low volumes of sample, and it is particularly suitable for breath analysis. For most VOCs, detection limits between 20 and 500 pptv were obtained by pre-concentrating 25 ml of a humidified standard gas mixture at a flow rate of 15 ml min^-1. For all compounds, inter- and intra-day precisions were always below 15%, confirming the reliability of the method. The procedure was successfully applied to the analysis of exhaled breath samples collected from forty heart failure (HF) patients during their stay in the University Hospital of Pisa. The majority of patients (about 80%) showed a significant decrease of breath acetone levels (a factor of 3 or higher) at discharge compared to admission (acute phase) in correspondence to the improved clinical conditions during hospitalization, thus making this compound eligible as a biomarker of HF exacerbation.

Antioxidant and inflammatory biomarkers for the identification of prodromal Parkinson's disease

OBJECTIVES

We explored the role of oxidative stress and inflammatory molecules as potential Parkinson (PD) biomarkers and correlated biological with non-motor abnormalities (olfactory impairment and dysautonomia), in patients with idiopathic REM behavior disorder (iRBD) (prodromal PD) and established PD.

METHODS

We recruited 11 iRBD and 15 patients with idiopathic PD (Hohen&Yahr 1-3, on L-DOPA and dopamine agonists combination therapy) and 12 age- and sex-matched controls (CTRL). We measured total olfactory score (TOS), autonomic function [deep breathing (DB), lying to standing (LS) and Valsalva manoeuvre (VM) ratios], blood reduced glutathione (Br-GSH), oxidative stress and inflammatory markers (neopterin).

RESULTS

Anosmia was similarly prevalent in iRBD (36%) and PD (33%) patients, but absent in CTRL. Orthostatic hypotension was more common among iRBD (73%) and PD (60%) than in CTRL (25%). By univariable ordinal logistic regression, TOS, Br-GSH, LS and VM ratio worsened from CTRL to iRBD and PD groups. Only reduced Br-GSH levels (p=0.037, OR=0.994; 95%CI 0.988-1.000) were independently associated to PD. TOS correlated with Br-GSH (R=0.34, p=0.037), VM ratio (R=0.43, p=0.015), and neopterin (rho=0.39, p=0.016).

CONCLUSIONS

Reduced systemic antioxidant capacity is found in prodromal and overt PD and may represent, in association with olfactory loss and cardiovascular dysautonomia, a useful biomarker for an integrative, early diagnosis of PD.

A dynamic control algorithm based on physiological parameters and wearable interfaces for adaptive ventricular assist devices

In this work we present an innovative algorithm for the dynamic control of ventricular assist devices (VADs), based on the acquisition of continuous physiological and functional parameters such as heart rate, blood oxygenation, temperature, and patient movements. Such parameters are acquired by wearable devices (MagIC & Winpack) and sensors implanted close to the VAD. The aim of the proposed algorithm is to dynamically control the hydraulic power of the VAD as a function of the detected parameters, patient's activity and emotional status. In this way, the cardiac dynamics regulated by the proposed autoregulation control algorithm for sensorized VADs, thus providing new therapy approaches for heart failure.

Hemodynamic Effects of Ventricular Assist Device Implantation on Norwood, Glenn, and Fontan Circulation: A Simulation Study

The growing population of failing single-ventricle (SV) patients might benefit from ventricular assist device (VAD) support as a bridge to heart transplantation. However, the documented experience is limited to isolated case reports. Considering the complex and different physiopathology of Norwood, Glenn, and Fontan patients and the lack of established experience, the aim of this work is to realize and test a lumped parameter model of the cardiovascular system able to simulate SV hemodynamics and VAD implantation effects to support clinical decision. Hemodynamic and echocardiographic data of 30 SV patients (10 Norwood, 10 Glenn, and 10 Fontan) were retrospectively collected and used to simulate patients' baseline. Then, the effects of VAD implantation were simulated. Simulation results suggest that the implantation of VAD: (i) increases the cardiac output and the mean arterial systemic pressure in all the three palliation conditions (Norwood 77.2 and 19.7%, Glenn 38.6 and 32.2%, and Fontan 17.2 and 14.2%); (ii) decreases the SV external work (Norwood 55%, Glenn 35.6%, and Fontan 41%); (iii) decreases the pressure pulsatility index (Norwood 65.2%, Glenn 81.3%, and Fontan 64.8%); (iv) increases the pulmonary arterial pressure in particular in the Norwood circulation (Norwood 39.7%, Glenn 12.1% and Fontan 3%); and (v) decreases the atrial pressure (Norwood 2%, Glenn 10.6%, and Fontan 8.6%). Finally, the VAD work is lower in the Norwood circulation (30.4 mL·mm Hg) in comparison with Fontan (40.3 mL·mm Hg) and to Glenn (64.5 mL·mm Hg) circulations. The use of VAD in SV physiology could be helpful to bridge patients to heart transplantations by increasing the CO and unloading the SV with a decrement of the atrial pressure and the SV external work. The regulation of the pulmonary flow is challenging because the Pap is increased by the presence of VAD. The hemodynamic changes are different in the different SV palliation step. The use of numerical models could be helpful to support patient and VAD selection to optimize the clinical outcome.

An autoregulation unit for enabling adaptive control of sensorized left ventricular assist device

This paper describes an integrated system for facing heart failures (HF) in an innovative way. Existing left ventricular assist devices (LVAD or VAD) are usually devoted to blood pumping without the possibility to adapt the speed to patient conditions during everyday activities. This is essentially due to the lack of sensorization, bulkiness, and the need of relying on device-specific controllers with reduced computing ability for the existing ventricular assist systems. In this work, an innovative integrated and portable device, the ARU, is presented for enhancing VADs applicability as a long-term solution to HF. The ARU is an universal device able to fulfill with the needs of sensorized VADs in terms of data storing, continuous monitoring, autoregulation and adaptation to patient condition changes during daily activities. The ARU is able to wirelessly interface wearable devices for offering additional monitoring features from remote. The ARU functionalities on bench have been tested by the interfacing with a sensorized VAD platform in order to prove the feasibility of the approach. Experiments of local and remote VAD speed changes and autoregulation algorithms have been successfully tested showing response time of 1 s.

Experimental integration of Autoregulation Unit for left ventricular assist devices in a cardiovascular hybrid simulator

In this paper, an Autoregulation Unit (ARU) for left ventricular sensorized assist devices (LVAD) has been used with a cardiovascular hybrid simulator mimicking physiological and pathological patient conditions. The functionalities of the ARU have been demonstrating for the successful receiving and visualization of system parameters, sending of commands for LVAD speed changes, and enabling of the autonomous flow control algorithm. Experiments of speed changes and autoregulation are reported, showing the feasibility of the approach for both local and remote control of a LVAD.

Inflammation blood and tissue factors of plaque growth in an experimental model evidenced by a systems approach

Purpose: The multifactorial pathogenesis of coronary atherosclerotic lesion formation has been investigated in a swine model of high cholesterol diet induced atherogenesis and data processed by a systems approach.

Methods: Farm pigs were fed on standard or high cholesterol diet of 8 and 16 weeks duration. Plasma assessment of total cholesterol, HDL, LDL, and ELISA of some cytokines and ICAM-1 were performed on baseline and end-diet samples. Segments of the right coronary artery were incubated for 24 h in serum-free medium to collect secreted proteins and their expression analyzed by mass spectrometry. Data of plasma and tissue factors were processed by a statistical systems inference approach: both histologic parameters of coronary intimal thickness (IT) and of lesion area (LA) were chosen as dependent variables (coronary atherosclerotic burden).

Results: Relations among plasma adhesion molecules, cytokines, lipoproteins, tissue proteins and histology indexes were integrated in a model regression scheme. Bayesian model averaging (BMA) variable selection was chosen as a method to identify relevant factors associated to atherosclerotic burden: TNFα was identified as an associated plasma marker, oxLDL and HDL as relevant lipoproteins; macrophage function related antioxidant Catalase enzyme, lysosome associated Cathepsin D, S100-A10, and Transforming growth factor-beta-induced protein ig-h3 were identified and selected as associated to atherogenesis outcome.

Conclusions: The results of this systems approach are consistent with the hypothesis that, in high cholesterol diet-induced experimental atherogenesis, the interaction between plasma cytokines, lipoproteins and artery-specific proteins, influences lesion initiation and growth. In particular, some macrophage function related proteins are found significantly and positively associated to atherosclerotic burden, suggesting a novel molecular framework into the atherogenesis-inflammatory disorder.

Adverse event prediction in patients with left ventricular assist devices

This work presents the Treatment Tool, which is a component of the Specialist's Decision Support Framework (SDSS) of the SensorART platform. The SensorART platform focuses on the management of heart failure (HF) patients, which are treated with implantable, left ventricular assist devices (LVADs). SDSS supports the specialists on various decisions regarding patients with LVADs including decisions on the best treatment strategy, suggestion of the most appropriate candidates for LVAD weaning, configuration of the pump speed settings, while also provides data analysis tools for new knowledge extraction. The Treatment Tool is a web-based component and its functionality includes the calculation of several acknowledged risk scores along with the adverse events appearance prediction for treatment assessment.

Post-operative elimination of sevoflurane anesthetic and hexafluoroisopropanol metabolite in exhaled breath: pharmacokinetic models for assessing liver function

Sevoflurane (SEV), a commonly used anesthetic agent for invasive surgery, is directly eliminated via exhaled breath and indirectly by metabolic conversion to inorganic fluoride and hexafluoroisopropanol (HFIP), which is also eliminated in the breath. We studied the post-operative elimination of SEV and HFIP of six patients that had undergone a variety of surgeries lasting between 2.5 to 8.5 h using exhaled breath analysis. A classical three compartments pharmacokinetic model developed for the study of environmental contaminants was fitted to the breath data. We found that SEV kinetic behavior following surgery (for up to six days) is consistent across all subjects whereas the production and elimination of HFIP varies to some extent. We developed subject specific parameters for HFIP metabolism and interpreted the differences in the context of timing and dose of anesthesia, type of surgery, and specific host factors. We propose methods for assessing individual patient liver function using SEV as a probe molecule for assessing efficiency of liver metabolism to HFIP. This work is valuable not only for the clinical study of metabolism recovery, but potentially also for the study of the interaction of other manufactured and environmental compounds with human systems biology in controlled exposure and observational studies.

Automated knowledge-based fuzzy models generation for weaning of patients receiving ventricular assist device (VAD) therapy

The SensorART project focus on the management of heart failure (HF) patients which are treated with implantable ventricular assist devices (VADs). This work presents the way that crisp models are transformed into fuzzy in the weaning module, which is one of the core modules of the specialist's decision support system (DSS) in SensorART. The weaning module is a DSS that supports the medical expert on the weaning and remove VAD from the patient decision. Weaning module has been developed following a "mixture of experts" philosophy, with the experts being fuzzy knowledge-based models, automatically generated from initial crisp knowledge-based set of rules and criteria for weaning.

Knowledge Editor and execution engine development for optimal ventricular assist device weaning

In this work, the weaning module of the SensorART specialist decision support system (SDSS) is presented. SensorART focuses on the treatment of patients suffering from end-stage heart failure (HF). The use of a ventricular assist device (VAD) is the main treatment for HF patients. However in certain cases, myocardial function recovers and VADs can be explanted after the patient is weaned. In that framework an efficient module is developed responsible for the selection of the most suitable candidates for VAD weaning. In this study we describe all technical specifications concerning its two main sub-modules of the weaning module, of the Clinical Knowledge Editor and the Knowledge Execution Engine.

A new technique for total hepatectomy in the pig for testing liver support devices

BACKGROUND

A large animal model of total hepatectomy is suitable to test the efficacy of any system designed to support patients in hepatic coma. The models previously described in the pig entail a significant degree of surgical trauma, which might alter the evolution of the ensuring hepatic failure and compromise the reproducibility of the model.

METHODS

Twenty-eight pigs underwent a total hepatectomy according to a new technique. A model was considered satisfactory when it required no blood transfusions and when hematologic and hemodynamic parameters determined before, during, and until 4 hours after hepatectomy showed no significant variations. Moreover, to revive the pattern of hepatic coma produced in the anhepatic model, 7 pigs were monitored until brain death occurred.

RESULTS

Twenty-five pigs (89%) underwent a smooth total hepatectomy with minimal variations of the selected parameters. They constituted a highly homogeneous group. Survival of the 7 pigs, followed up until brain death occurred, ranged from 625 to 1595 minutes (mean 1013.57 minutes). The animals remained stable until a few hours before brain death, an event heralded by a final sharp increase of the serum ammonia level and by a well-evident decline of both arterial pressure and liver-dependent clotting factors.

CONCLUSIONS

This technique of total hepatectomy allows the construction of a reproducible model of anhepaty suitable to test the efficacy of any system conceived to temporarily replace hepatic functions.

Detection of perfusion defects during coronary occlusion and myocardial reperfusion after thrombolysis by intravenous administration of the echo-enhancing agent BR1

The purpose of this study was to detect myocardial perfusion defects as a result of coronary occlusion and myocardial reperfusion after thrombolysis with intravenous (i.v.) administration of the echo contrast agent BR1 (Bracco Research, Switzerland), which consists of microbubbles (median diameter 2.5 microm) containing sulfur exafluoride in a phospholipidic shell. To generate a coronary thrombosis, a copper coil was advanced into the left circumflex coronary artery in eight anesthetized dogs with opened chest cavities. Coronary occlusion occurred 18 +/- 10 minutes after the insertion of the coil and was documented both by an electromagnetic flow meter (as zero blood flow) and by radiolabeled microspheres (as myocardial perfusion defect). After 2 hours of occlusion, streptokinase was infused i.v.; reperfusion was documented by both the flow-meter and microspheres. Left ventricular cavity enhancement was apparent after all contrast injections. Peak cavity intensity did not increase with dose and was not affected by signal processing (suggesting signal saturation), whereas the duration of contrast effect significantly increased with the dose (from 26 +/- 16 to 147 +/- 74 seconds). Myocardial contrast intensity also increased after contrast (from 15 +/- 12 to 21 +/- 18 gray level/pixel, p < 0.001). Contrast echo detected myocardial perfusion defects (corresponding to 17% +/- 11% of LV cross-sectional area) in all the injections performed during coronary occlusion and detected myocardial reperfusion with a sensitivity of 50% versus microspheres. The extent of perfusion defects by contrast echo showed a good correlation with microspheres (r = 0.73). Myocardial reperfusion was not detected by changes in heart rate, aortic pressure, pulmonary arterial pressure, cardiac output, left ventricular fractional area change, or wall-motion score index. Hemodynamic parameters were not affected by contrast injections. Thus, the i.v. administration of BR1 allows us to accurately detect myocardial perfusion defects during coronary occlusion and, to a lesser extent, myocardial reperfusion after thrombolysis.

Hierarchical structure of personality in patients with acute myocardial infarction

The personalities in coronary heart disease have often been investigated using the Sixteen Personality Factor Questionnaire (16 PF) of Cattell. The aims of this study were to verify the third-order factor structure of 16 PF and to assess the third-order factors in a group of patients with acute myocardial infarction as compared with a group of normal subjects. The primary 16 factor scores of the over-all population of infarcted patients and normal subjects were factored and the results rotated obliquely (dquart solution) to produce nine second-order factors. In a second step the nine second-order factors extracted were processed again by factor analysis and the third-order structure was achieved. The five third-order factors obtained were named Inhibition (α), Internal Feeling (β), Maladaptation (γ), Self-concern and Control (δ), plus an Unidentified Factor (ε). The patients with acute myocardial infarction were significantly different from normal subjects in scores on α, β, γ, and δ. The profile analysis of these four third-order psychological variables differentiated the two groups. In conclusion, the patients with acute myocardial infarction are characterized by difficulties in communication, emotional expression, and adaptation to stress and by a tendency to strong self-control and poor attention to their internal feelings.

Surgical research in orthotopic liver transplantation: experiences in the pig model

Since the very beginning of liver transplantation in humans, research in animals has had close relationship with clinical practice. Results obtained in animals have been transferred to the clinics and problems borne in the clinics have been addressed again in animals for to be answered clearly. In this review the authors report their experience of transplantation in the pig model and discuss the significance of a team cooperation in the laboratory as a preparatory step for clinical practice.

Cattell's 16 PF and PSY inventory: relationship between personality traits and behavioral responses in patients with acute myocardial infarction

The aim of this study was to investigate the relationships between personality and behavioral responses in patients with acute myocardial infarction. In a first step, a new instrument (PSY Inventory) for assessment of six behavioral characteristics (Sense of Responsibility, Energy and Competitiveness, Obsessive Behavior, Anger and Hostility, Stress-related Disturbances, Time Urgency) was developed by using factor analysis on intercorrelations of responses from 524 subjects of the general population. Internal consistency reliability for each of the PSY subscales was estimated by Cronbach alpha coefficients. In a second step, the PSY Inventory was administered with the Cattell 16 PF Questionnaire to 838 patients affected by acute myocardial infarction. Significant correlations although relatively low in magnitude for PSY Inventory subscales and certain scales of the Cattell 16 PF were found. With factor analysis on 22 variables (including the six PSY Inventory subscales and the 16 scales of the Cattell 16 PF), five second-order factors were identified, namely, Extraversion, Neurotic Anxiety, Superego Strength, Pathemia, and Neurotic Hostility. While a Pathemia Factor (characterized by sensitivity, imagination, and self-sufficiency) was factorially independent of scales of the PSY Inventory, Extraversion, Neurotic Anxiety, Superego Strength, and Neurotic Hostility Factors were composed of the PSY Inventory scales and Cattell 16 PF scales combined. These relationships would reflect the concordance of internal constructs for behavioral measures of the PSY Inventory and those of personality traits of the 16 PF Questionnaire in patients with acute myocardial infarction.

The second-order factor structure of Cattell's 16 PF in patients with coronary heart disease

The second-order factor structure of the 16 Personality Factor Questionnaire (16 PF) was validated on a sample of 940 patients hospitalized for coronary heart disease. The purpose of this investigation was the evaluation of second-order factor structure, already confirmed for normal subjects, of a selected pathological population. With factor analyses, oblique promax rotation, five second-order factors were identified, namely, Anxiety, Extraversion, Pathemia, Control, and an unidentified factor. These results were compared with those of Cattell's and Krug's studies. As a high congruence coefficient was shown, a good replication of Cattell's originally published second-order factors was achieved.

[Personality and acute myocardial infarction: distinctive traits]

AIM OF THE STUDY

Aim of this study is to evaluate the presence of peculiar personality traits in patients with acute myocardial infarction as compared with normal subjects.

METHODS

The Sixteen Personality Factor Questionnaire (16 PF) by Cattell (D form) is administered to 654 patients (558 males, 96 females) hospitalized for acute myocardial infarction in 16 coronary care units and to 398 normal subjects (261 males, 137 females). The diagnosis of myocardial infarction is made according to the presence of at least two of the following criteria: prolonged chest pain, elevation of CPK and CPKMB (twice the upper normal values), Q wave on the electrocardiogram. The normality of the control group is assured by specific exclusion criteria (cardiac or psychiatric disease, metabolic and endocrine disease, continued therapeutic treatment for any organic disease, or continued assumption of hypnotic and/or anxiolytic drugs).

RESULTS

In comparison with the control group, infarcted males result significantly different for factors C, N, Q1, Q4 (p < 0.001), for factors B, O (p < 0.01) and A, H, I (p < 0.05). Females with myocardial infarction differ significantly for factors C, O and I (p < 0.05). Four second-order factors is obtained from Cattell's 16 PF by factorial analysis: QI (anxiety), QII (extroversion), QIII (sensitivity), QIV (superego strength). The infarcted population shows statistically significant differences compared with controls: infarcted males show higher QI (p < 0.001) and lower QII and QIII (p < 0.05) while infarcted females have higher QI (p < 0.05).

CONCLUSIONS

These differences confirm that peculiar personality traits can be found in patients with acute myocardial infarction. In particular, infarcted males are emotionally unstable, anxious, rigid and depressed, and have problems in communication with others; infarcted females differ from the normal population for being emotionally unstable, anxious and for having a less flexible mental disposition. The higher anxiety level in patients with acute myocardial infarction may be related to the neuroticism that, in other studies, has been often found to be associated with cardiovascular disease. In conclusion, with respect to the normal population, patients with acute myocardial infarction appear to be anxious introverts, with conflictual personality.

Intracoronary air-filled albumin microspheres for myocardial blood flow measurement

OBJECTIVES

The aim of this study was to explore the possibility of quantifying coronary blood flow by myocardial contrast echocardiography with air-filled serum albumin microspheres (Albunex).

BACKGROUND

Air-filled albumin microspheres have been proposed as an intravascular tracer for the study of myocardial perfusion by contrast echocardiography.

METHODS

In six anesthetized open chest dogs, the left circumflex coronary artery was cannulated and perfused by a roller pump with blood from the femoral artery. Both air-filled albumin microspheres (0.4 ml, 2 x 10(8) spheres/ml) and technetium-99m-labeled albumin were injected as a bolus into the coronary cannula at baseline and after treatment with dipyridamole (0.56 mg/kg body weight intravenously for 4 min). Two-dimensional echographic images of the left ventricular short axis were digitized to generate myocardial time-intensity curves; myocardial radioactivity was measured by an external detector to generate radionuclide time-activity curves.

RESULTS

After dipyridamole, left circumflex coronary artery blood flow (as measured by both the pump and an electromagnetic flow meter) significantly increased (from 1.06 +/- 0.28 to 3.61 +/- 1.43 ml/min per g of myocardium). Peak intensity and rise time of contrast echo curves were able to differentiate baseline myocardial perfusion from coronary hyperemia but did not show any significant correlation with coronary blood flow. A weak inverse correlation with coronary blood flow was provided by myocardial mean transit time of air-filled albumin microspheres (r = 0.33). Conversely, a close inverse correlation with coronary blood flow was obtained by myocardial mean transit time of technetium-99m-labeled albumin (r = 0.95). Myocardial transit time of air-filled albumin microspheres (1.95 +/- 0.60 s) was also markedly shorter than that of labeled albumin (5.35 +/- 3.43 s, p < 0.001) and the measurements were less reproducible.

CONCLUSIONS

In this experimental study, coronary blood flow was not adequately quantified by myocardial contrast echocardiography with intracoronary injection of air-filled albumin microspheres.

Myocardial washout of sonicated iopamidol does not reflect the transmural distribution of coronary blood flow

It has been shown in previous studies that myocardial contrast echocardiography provides quantitative information on coronary blood flow. However, the ability of contrast echo to assess the transmural (endo/epicardial) distribution of blood flow is still debated. To test this hypothesis, the left circumflex coronary arteries of six anaesthetized open-chested dogs were cannulated and perfused with blood from the femoral artery. At different rates of coronary blood flow, during adenosine-induced coronary vasodilation, sonicated iopamidol and radionuclide labelled microspheres were injected into the coronary cannula, immediately proximal to a mixing chamber. Two-D echo images were digitized and myocardial time-intensity curves were obtained for the endocardial, mid- and epicardial layers. A good correlation existed between contrast washout of the entire ventricular wall and coronary flow (r = 0.85). However, the washout rate from the endo-, mid- and epicardial layers showed weak correlations with corresponding regional blood flows measured by microspheres (r = 0.56, 0.71 and 0.58, respectively). No significant relationship was found between the endo/epicardial washout ratio and the corresponding flow ratio by microspheres. Thus, measurement of the transmural distribution of coronary blood flow by myocardial contrast echocardiography remains an elusive goal.

Effects of coronary blood flow on myocardial grey level amplitude in two dimensional echocardiography: an experimental study

OBJECTIVE

The aims were: (1) to evaluate whether differences in absolute and cyclic echocardiographic image amplitude exist in different layers (subendocardium and subepicardium) and regions (septal, anterior, lateral, inferior wall) of the canine left ventricle; (2) to assess the dependence of these variables upon local variations of coronary blood flow.

METHODS

In six anaesthetised open chest dogs the circumflex coronary artery was cannulated and perfused by a roller pump with blood from their own femoral artery. Maximum coronary vasodilatation was obtained by continuous adenosine infusion. The absolute values and the transmural distribution of coronary blood flow were measured by radionuclide labelled microspheres. Echo images were obtained in short axis view by a commercially available electronic sector scanner with a 5.0 MHz transducer directly placed on the epicardial surface of the right ventricle, and digitised off-line into a matrix of 256 x 256 pixels with 25% grey level per pixel. The average grey level was calculated for each region of interest.

RESULTS

In 32 different conditions, circumflex flow ranged from 0.80 to 12.89 ml.min-1.g-1 and the endocardial/epicardial ratio of flow from 0.53 to 1.73. In the circumflex region (subjected to flow changes) segmental amplitude varied from 76(SD 20) (end diastole) to 56(18) (end systole), p < 0.001. In all regions, a consistent cyclic variation was found, ranging from 9(14) to 28(16)%. For all levels of flow, subendocardial and subepicardial regions showed similar values of both absolute amplitude and cyclic variation. No significant relationship was found between transmural distribution of blood flow and either segmental amplitude (r = 0.26) or cyclic variation (r = 0.04).

CONCLUSIONS

(1) a consistent cyclic grey level variation is present in all regions of the canine left ventricle, but subendocardial and subepicardial layers show similar values of both absolute amplitude and cyclic variation; (2) in the absence of severe underperfusion and echocardiographically detectable dyssynergy, absolute amplitude and cyclic variation are totally unrelated to changes in coronary blood flow.

Myocardial washout of sonicated iopamidol reflects coronary blood flow in the absence of autoregulation

OBJECTIVES

The aim of the study was to evaluate the relation between measurements derived from myocardial contrast echocardiography and coronary blood flow.

BACKGROUND

Contrast echocardiography has the potential for measuring blood flow.

METHODS

In six open chest anesthetized dogs, the left circumflex coronary artery was cannulated and perfused with blood drawn from the left femoral artery. While adenosine was infused into the circuit, circumflex flow was generated by a calibrated roller pump to the point of abolishing coronary autoregulation. At each of 25 levels of coronary blood flow, paired bolus injections of sonicated iopamidol were performed proximal to a mixing chamber. The perfused area of the left circumflex coronary artery was labeled by radioactive microspheres injected into the perfusion line. Two-dimensional echocardiographic images of the left ventricular short axis were digitized off-line, and myocardial videodensity was measured in the area perfused by the left circumflex coronary artery to generate time-intensity curves.

RESULTS

The washout slope of curves showed a good correlation with coronary blood flow, ranging from 0.5 to 12.5 ml/min per g of tissue. This correlation was good both in individual dogs (correlation coefficient [r] ranging from 0.78 to 0.96) and in the group of animals as a whole (r = 0.85). Washout slope also showed a good correlation with coronary diastolic pressure (r = 0.80), which ranged from 23 to 114 mm Hg, suggesting a possible primary effect of pressure on contrast washout. However, coronary blood flow appeared to be a stronger predictor of washout slope (partial F = 26.5, p < 0.001) than did perfusion pressure (partial F = 5.9, p < 0.05 by multiple regression). The injection to injection variability in myocardial washout slope appeared to be high (24%). The gamma variate fitting of curves did not improve the correlation with coronary flow (r = 0.78).

CONCLUSIONS

Myocardial washout of sonicated iopamidol reflects coronary blood flow in a model in which coronary autoregulation is abolished.

Influence of selective autonomic decentralization on myocardial deoxyglucose uptake initiated by cardio-cardiac reflexes

The aim of this study was to evaluate the effect of autonomic reflexes as initiated by stimulation of the right recurrent cardiopulmonary nerve afferent axons on myocardial deoxyglucose uptake and to determine how such uptake can be modified by selective neural ablation. The afferent axon in the right recurrent cardiopulmonary nerve was stimulated 30 s/min for 1 h in five anesthetized open-chest dogs in which 14-C labeled deoxyglucose was i.v. injected at the beginning of the stimulation period. Three additional sham-operated dogs served as neurally intact controls. Concentrations of label and glucose were measured in plasma. Regional myocardial deoxyglucose concentration was measured by quantitative autoradiography, following the calibration of plasma samples autoradiographic density by beta counting. Stimulation of right recurrent cardiopulmonary nerve afferent axons in the intact nervous system preparation did not significantly enhance deoxyglucose uptake as compared to neurally intact controls. When the right cervical vagosympathetic complex was cut a similar uptake was observed. Following decentralization of the right stellate ganglion, uptake was markedly reduced, as well as when the right cervical vagosympathetic was cut and the right stellate ganglion decentralized.

CONCLUSIONS

Activation of afferent axons from cardiopulmonary receptors does not alter myocardial deoxyglucose uptake. Reduction in uptake occurs following unilateral stellate ganglion decentralization.

[A mathematical model of the vascular architecture and of the distribution of resistances in the coronary tree]

The architecture and resistance distribution of the coronary arteriolar tree downstream 100 mu diameter vessels are still largely unknown, due to technical difficulties in direct visualization. In this study we propose a mathematical model of the architecture and the single vessel resistance distribution of terminal arteriolar vasculature in the beating dog heart, based on the analysis of embolization-induced changes of total coronary resistance. Coronary embolization was performed by injecting several boluses of 15 mu (6 cases) and 25 mu (6 cases) plastic microspheres into the maximally vasodilated (adenosine infusion) left circumflex artery of the open chest dog. The relation between the number of plastic beads progressively injected to embolize 15 mu and 25 mu vessels and the resulting increase in total coronary resistance (occlusion function) was obtained in each experiment. If we consider a binary symmetric vascular tree with i) equal resistance for vessels of the same branching order and ii) optimal ratio between resistance of parent and daughter vessels at all branching sites, the simulation of embolization in such a system shows that the occlusion function of the terminal vessels N in the linear portion between 0 and N/2 occluded vessels has a slope S' which is 5.6 times lower than the slope S" between N/2 and 3/4 N occluded vessels and 3.6 times lower than the S' of the occlusion function of the preterminal vessels. The occlusion function in our experiments has a ratio S"/S' close to that predicted by the model and a ratio between the S' of the 25 mu and that of 15 mu experiments equal to 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional myocardial deoxyglucose uptake following electrical stimulation of canine efferent sympathetic cardiopulmonary nerves

OBJECTIVE

The aim was to study the effect of stimulating individual acutely decentralised cardiopulmonary nerves on myocardial uptake of deoxyglucose.

METHODS

In 17 open chest anaesthetised dogs the efferent axons of individual decentralised cardiopulmonary nerves were stimulated intermittently throughout 1 h while haemodynamic variables were measured. Tritiated 2-deoxyglucose was injected intravenously at the beginning of stimulation. Atropine was given when a cardiopulmonary nerve with efferent parasympathetic axons was studied. Distribution of label was detected using a multiwire proportional chamber. It was compared to blood concentration of deoxyglucose to permit quantitative mapping of regional myocardial uptake during the stimulation of each nerve.

RESULTS

Neural stimulation of most of sympathetic efferent cardiopulmonary nerves increased deoxyglucose uptake in all myocardial tissue. Uptake was greatest in the left ventricle, less in the right ventricle, and least in the left and right atria. Regional myocardial uptake was also observed following individual cardiopulmonary nerve stimulation. Some nerves caused greater uptake than others. Cardiopulmonary nerves which are known to enhance inotropism when stimulated induced little increase of deoxyglucose uptake, whereas other nerves known to exert little positive inotropic effect induced considerable uptake. There was no correlation between haemodynamic changes and deoxyglucose uptake.

CONCLUSIONS

It appears that (1) efferent sympathetic axons in one cardiopulmonary nerve can preferentially increase deoxyglucose uptake in specific regions of the myocardium and (2) the mechanisms responsible for enhancement of glucose uptake may differ from those responsible for inotropic responses.

Beta-receptor subtypes in the canine coronary circulation

The principal difficulty in determining the subtype of coronary vascular beta-receptors in vivo is to avoid the local metabolic coronary vasodilation that occurs secondary to activation of myocardial beta-receptors. Therefore, a nonbeating cardiac preparation without chronotropic or inotropic effects is needed. In this study, the coronary circulation was perfused at constant pressure in closed-chest chloralose-anesthetized dogs. The increase in coronary blood flow due to intracoronary injections of the combined beta 1- and beta 2-agonist isoproterenol was determined during prolonged asystoles after the cessation of cardiac pacing in atrioventricular heart-blocked animals. Both beta 1-selective (practolol and L 650,744) and beta 2-selective (ICI 118,551) antagonists blocked isoproterenol-induced coronary vasodilation. In contrast, isoproterenol vasodilation in the femoral circulation was blocked by beta 2- but not by beta 1-selective antagonists. In conclusion, both beta 1- and beta 2-receptors in coronary resistance vessels are stimulated by isoproterenol to produce vasodilation during prolonged asystoles, when cardiac chronotropic and inotropic effects are absent.

Transmural redistribution of coronary resistance during embolization: a clue to intramyocardial small artery architecture

The aim of this study is to assess vascular architecture and the single vessel resistance distribution of the subepicardial (epi) and subendocardial (endo) layers of the left ventricular wall. For this purpose, coronary embolization was performed by injecting three boluses of 25 microns plastic microspheres into the maximally vasodilated left circumflex artery of six dogs; transmural blood flow was assessed by 15-microns radioactive microspheres. A branching tree model of the intramyocardial small artery system--whose general characteristics were described in a previous study (Pelosi et al., 1987, Microvasc. Res. 34, 318-335)--was developed and its parameters were tested against the increase in epi and endo coronary resistance observed during embolization. Embolization produced a significantly greater increase in epi resistance after each bolus injection (from 10.3 +/- 1.1 to 195.6 +/- 32.5 mm Hg/ml/min/g after the last bolus, P less than 0.001) as compared to endo resistance (from 10.3 +/- 2.0 to 56.5 +/- 8.2 mm Hg/ml/min/g after the last bolus, P less than 0.001); as a consequence, the epi/endo resistance ratio increased from 1.09 +/- 0.11 to 1.50 +/- 0.13, 2.48 +/- 0.51, and 3.66 +/- 0.42 (P less than 0.05 for all embolizing injections). The experimental relation (occlusion function) between the number of embolizing beads injected and the epi and endo resistance values was used to define the parameters of the epi and endo branching tree model. Assuming that the embolizing microspheres lodge in vessels of similar resistance (that is similar diameter and length) in the two layers, the experimental results indicate that the intramyocardial small artery system can be depicted as a symmetric dichotomous branching tree with twofold more terminal vessels in the endo than in the epi.

Coronary effects of adenosine in conscious man

Adenosine has been reported to play an important role in several cardiac functions, including the regulation of total and regional myocardial perfusion. This hypothesis is based on extensive investigations in animal models, but very limited information is available on the cardiovascular actions of adenosine in conscious man and the effects of the intracoronary administration of adenosine are unknown. The purpose of this study was to measure total and regional coronary blood flow after bolus injections of 0.1, 0.5, 1.0, and 2.5 mg of adenosine into the left anterior descending coronary branch. A three-thermistor thermodilution catheter was advanced into the coronary sinus to measure simultaneously the great cardiac vein flow and the coronary sinus flow. Six patients with normal coronary angiograms and normal ventricular function completed the study. Intracoronary injections of adenosine were free from significant adverse effect and caused a dose-related increase of great cardiac vein flow. A linear relation was found between flow increment and the log of adenosine dose (y = 18.929x + 74.84, r2 = 0.951). The highest flow, measured after the maximal dose, was almost three times greater than control flow (155 +/- 2 vs 58 +/- 3 ml min-1, P less than 0.001). We also observed a flow response in the territory not directly exposed to adenosine, as indicated by a marked increase of coronary sinus blood flow that was linearly related to the adenosine dose (y = 29.113x = 112.635, r2 = 0.98). These preliminary observations suggest: (1) Intracoronary injections of adenosine in conscious man can be performed without significant adverse effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional and global biventricular function during dipyridamole stress testing

This study assesses the relation between regional ventricular performance (using 2-dimensional echocardiography) and global systolic and diastolic indexes of biventricular myocardial function (using hemodynamic monitoring) during dipyridamole stress testing. Simultaneous 2-dimensional echocardiographic and biventricular hemodynamic monitoring during dipyridamole infusion (0.56 mg/kg over 4 minutes) was performed in 19 patients. All patients had a normal resting function. Eleven of the 19 patients had a positive echocardiography test (new wall motion dyssynergy with dipyridamole) and they formed group 1. Eight patients had a negative echocardiography test (group 2). During baseline conditions, no significant differences were found in the 2 groups: rate pressure product (107 +/- 16 vs 108 +/- 13 mm Hg x beats/min x 1/100), positive left ventricular (LV) dP/dt (1,950 +/- 473 vs 2,262 +/- 430 mm Hg/s), negative LV dP/dt (-2,069 +/- 620 vs -2,205 +/- 245), LV end-diastolic pressure (8.2 +/- 4.4 vs 9.6 +/- 4.0 mm Hg), right ventricular positive dP/dt (368 +/- 133 vs 400 +/- 190 mm Hg/s) and negative dP/dt (-281 +/- 89 vs -383 +/- 147). At peak dipyridamole, the 2 groups were different for LV end-diastolic pressure (20 +/- 10 vs 8 +/- 5 mm Hg, p less than 0.01), LV positive dP/dt (2,100 +/- 688 vs 3,013 +/- 851 mm Hg/s, p less than 0.01) and negative dP/dt (-1,868 +/- 518 vs -2,564 +/- 272, p less than 0.01). At peak ischemia, LV positive dP/dt increased slightly, but not significantly, while negative dP/dt decreased significantly (p less than 0.01) in comparison with resting values.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationships between cardiac pain and objective markers of transient myocardial ischemia

Cardiac pain is a key symptom for diagnosis of myocardial ischemia in man, even if a minority of transient myocardial ischemic episodes are painful. A multiparametric monitoring approach - associating non-invasive and invasive monitoring techniques during transient myocardial ischemia with and without pain - allows to achieve a clinical diagnosis and obtain information about the pathophysiology of the anginal syndrome.

Persistence of subendocardial perfusion after subtotal coronary embolisation

The effects of acute subtotal embolisation of small coronary arteries on regional coronary flow and vasodilator reserve were investigated in seven open chest dogs. Unlabelled plastic microspheres (26(2) micron in diameter) were injected as boluses of 200,000-400,000 microspheres into the circumflex artery. Embolisation was repeated until reactive hyperaemia was totally abolished, which occurred after the injection of 62,000(4000) microspheres per gram. Intracoronary adenosine was then infused for 20 min at 1.2 mg.min-1. Regional myocardial blood flow was measured by radioactive microspheres under control conditions, after coronary embolisation, and during adenosine infusion. Coronary blood flow (0.98(0.07) ml.min-1.g-1) was reduced to 0.66(0.08) ml.min-1.g-1 after embolisation (p less than 0.005) when reactive hyperaemia was practically abolished. Embolisation reduced epicardial flow from 0.93(0.08) to 0.40(0.09) ml.min-1.g-1 (p less than 0.001), whereas endocardial flow was unchanged (1.03(0.11) vs 0.92(0.14) ml.min-1.g-1; NS); as a consequence, the endocardial to epicardial flow ratio increased from the control value of 1.11(0.06) to 2.31(0.35) (p less than 0.005). Adenosine infusion increased coronary blood flow from 0.66(0.08) to 1.66(0.41) ml.min-1.g-1 (p less than 0.05). Endocardial blood flow increased more than epicardial blood flow, leading to a further increase in the endocardial to epicardial flow ratio (3.79(0.13); p less than 0.05). Thus it is concluded that (a) embolisation of small arteries abolishes the reactive hyperaemic response to transient coronary occlusion; (b) microembolisation predominantly reduces subepicardial perfusion; and (c) adenosine administration may increase total and regional flow after subtotal occlusion of coronary small arteries.

Small artery occlusion: a theoretical approach to the definition of coronary architecture and resistance by a branching tree model

The aim of this study was to evaluate the theoretical possibility of assessing the architecture of the coronary small artery circulation in vivo by the analysis of the increments in the total resistance of the vascular system caused by the progressive occlusion of the terminal vessels as would be possible in animal experiments by microsphere embolization. Different distributions of the resistance values of all the vessels have been obtained in branching tree models by means of only two parameters: (a) the resistance ratio between daughter and parent vessels at each branching site (KO); and (b) the resistance ratio between the two daughter vessels at each branching site (KV). Simulation of branching tree occlusion has been performed under two main conditions of resistance distribution: (1) symmetric resistance distribution, characterized by equal KO values at each branching site of the same level and by KV = 1, that is, equal resistance values for the vessel of the same level; and (2) asymmetric resistance distribution in dichotomous branching trees, wherein all the vessels may have different values of resistance; the variability in these values has however been restricted on the basis of physiological considerations. The analysis of the function of the total resistance vs the number of occluded vessels, obtained by a simulated progressive occlusion of the terminal vessels in these two systems, gives the following results: (1) in a symmetric branching tree, discontinuities are present in the occlusion function which permit identification of both the architecture and the resistance value of each single vessel of any unknown vascular tree; and (2) in the asymmetric model, the function does not allow a direct definition of the branching architecture and the values of resistance of each vessel; however, also in this case, any branching tree can be analyzed by means of a nonlinear optimization procedure which produces an equivalent symmetric branching tree. We conclude that, theoretically, the analysis of the occlusion function represents a valuable indirect approach to the quantitative study of the coronary microcirculation as well as of other vascular districts under steady flow conditions.