Myocardial Reserve Research Articles

Dynamic assessment of left ventricular coupling and myocardial reserve in patients with cardiogenic shock.

Pulmonary artery catheter haemodynamics are associated with improved survival in cardiogenic shock (CS). We investigated the utility of aortic pulsatility index (API) and cardiac power output (CPO) as surrogates for left ventricular (LV) coupling and myocardial reserve, respectively, in patients with CS undergoing dynamic assessment after a milrinone bolus. Patients with SCAI Stage C CS underwent a milrinone drug study (50 mcg/kg bolus infused over 10 min) to assess inotropic response. Haemodynamic measurements were obtained at baseline and following the bolus. Aortic pulsatility index and CPO were used to risk-stratify patients with the incidence of LV assist device (LVAD), orthotopic heart transplantation (OHT), or death at 1 year as the primary composite endpoint. Two hundred and twenty-four patients in SCAI Stage C CS underwent haemodynamics prior to milrinone bolus, and 117 patients had low baseline API < 1.45. Of the 117 patients, 88 had a final API < 2.2 after milrinone load, consistent with LV decoupling, in which 73% met the composite endpoint. The remaining 29 patients had a final API ≥ 2.2 consistent with LV recoupling, and only 55% met the composite endpoint (P = 0.046). Of the 117 patients, 40 patients had low myocardial reserve (final CPO < 0.77 W), in which 78% met the composite endpoint. Of the 77 patients who demonstrated myocardial reserve (final CPO ≥ 0.77 W), only 64% met the composite endpoint (P = 0.039). The use of API and CPO in a dynamic assessment after provocative testing led to improved risk stratification in patients with SCAI Stage C CS for clinical outcomes including LVAD, OHT, or death at 1 year.

Association of cardiac mechanical dyssynchrony indices with data of dynamic single-photon emission computed tomography of the myocardium: the role of the time interval between the stress test and recording

Introduction. According to ECG-synchronized myocardial perfusion imaging (MPI) mechanical dyssynchrony (MD) is a sensitive marker of impaired myocardial perfusion. However, its direct comparison with indicators of myocardial blood flow reserve (MFR) according to single-photon emission computed tomography (SPECT) was not carried out. Traditional MPI protocols imply a long gap between stress test and image acquisition, during which stress-induced changes may pass. It is potentially possible to reduce the time interval down to 5 minutes.Aim: To investigate the relationship between early and delayed MD indices and the data of MFR by means of SPECT.Material and Methods. The study included 20 patients with suspected coronary heart disease, preserved left ventricular ejection fraction (&gt; 55%) and without obstructive coronary artery lesions (&lt; 50%) according to multislice computed coronary angiography. All patients underwent dynamic SPECT (dSPECT) according to a two-day rest/stress protocol. Gated MPI was performed 60 minutes after radiopharmaceutical administration. Myocardial blood flow and reserve, as well as phase histogram standard deviation (PSD, degree) and phase histogram bandwidth (HBW, degree) from 5 minutes after radiopharmaceutical administration were obtained from the dSPECT data by postprocessing. Perfusion data as well as MD indices (PSD, HBW) were obtained from delayed images. Based on dSPECT data, patients were divided into 2 groups: with preserved (MFR ≥ 2.0) and reduced (MFR &lt; 2.0) myocardial blood flow reserve.Results. Correlation analysis showed that MD indices on stress test in early scan had a stronger association with MFR (PSD ρ = –0.68, p &lt; 0.001; HBW ρ = –0.68, p = 0.001) compared to those in delayed scan (PSD ρ = –0.38, p = 0.019; HBW ρ = –0.44, p = 0.005). According to multivariate regression analysis, PSD on stress test at early scan was the only independent predictor of reduced MFR (OR 1.29 (1.1; 1.53)). Stress PSD &gt; 22° obtained at early scanning had a sensitivity of 81% and specificity of 87% (AUC = 0.86, p &lt; 0.001) in predicting of reduced MFR.Conclusion. Left ventricular mechanical dyssynchrony indices obtained by early post-stress gated MPI have a stronger association with myocardial blood flow reserve indices.

The Influence of Kinetic Models and Attenuation Correction on Cadmium-Zinc-Telluride Single-Photon Emission Computed Tomography (CZT SPECT)-Derived Myocardial Blood Flow and Reserve: Correlation with Invasive Angiography Data.

(1) Background: The objective of this study was to determine the optimal post-processing model for dynamic cadmium-zinc-telluride single-photon emission computed tomography (CZT-SPECT). (2) Methods: A total of 235 patients who underwent diagnostic invasive coronary angiography within three months of the SPECT and those who had coronary computed tomography angiography (CCTA) before SPECT (within 3 months) were enrolled in this study. Each SPECT study was processed to obtain global and regional stress myocardial blood flow (sMBF), rest-MBF (rMBF), myocardial flow reserve (MFR) and flow difference (FD) estimates obtained with 1-tissue-compartment (1TCM) and net retention (NR) modes, both with and without attenuation correction. (3) Results: The use of AC led to significantly higher sMBF, rMBF and DF values obtained by 1TCM compared those values derived by 1TCM with NAC; the lowest values of stress MBF and rest MBF were obtained by 1TCM_NAC. The resting flow, MFR and DF were significantly (p < 0.005) higher in the AC model than in NAC. All quantitative variables were significantly (p < 0.05) higher in NR_NAC than in the 1TC_NAC model. Finally, sMBF, rMBF and FD showed significantly (p < 0.05) higher values by using 1TMC_AC compared to NR_AC. (4) Conclusions: We suggested that 1-compartment and net retention models correctly reflect coronary microcirculation and can be used for clinical practice for evaluating quantitative myocardial perfusion by dynamic SPECT. Attenuation correction is an important step in post-processing dynamic SPECT data, which increases the consistency and diagnostic accuracy of models.

An interventional sheep model of severe aortic valve stenosis hemodynamics for the evaluation of alterations in coronary physiology and microvascular function.

We aimed to develop a large animal model of subcoronary aortic stenosis (AS) to study intracoronary and microcirculatory hemodynamics. A total of three surgical techniques inducing AS were evaluated in 12 sheep. Suturing the leaflets together around a dilator (n = 2) did not result in severe AS. Suturing of a pericardial patch with a variable opening just below the aortic valve (n = 5) created an AS which was poorly tolerated if the aortic valve area (AVA) was too small (0.38-1.02 cm2), but was feasible with an AVA of 1.2 cm2. However, standardization of aortic regurgitation (AR) with this technique is difficult. Therefore, we opted for implantation of an undersized AV-bioprosthesis with narrowing sutures on the leaflets (n = 5). Overall, five sheep survived the immediate postoperative period of which three had severe AS (one patch and two bioprostheses). The surviving sheep with severe AS developed left ventricular hypertrophy and signs of increased filling-pressures. Intracoronary assessment of physiological indices in these AS sheep pointed toward the development of functional microvascular dysfunction, with a significant increase in coronary resting flow and hyperemic coronary resistance, resulting in a significantly higher index of microvascular resistance (IMR) and lower myocardial resistance reserve (MRR). Microscopic analysis showed myocardial hypertrophy and signs of fibrosis without evidence of capillary rarefaction. In a large animal model of AS, microvascular changes are characterized by increased resting coronary flow and hyperemic coronary resistance resulting in increased IMR and decreased MRR. These physiological changes can influence the interpretation of regularly used coronary indices.NEW & NOTEWORTHY In an animal model of aortic valve stenosis (AS), coronary physiological changes are characterized by increased resting coronary flow and hyperemic coronary resistance. These changes can impact coronary indices frequently used to assess concomitant coronary artery disease (CAD). At this point, the best way to assess and treat CAD in AS remains unclear. Our data suggest that fractional flow reserve may underestimate CAD, and nonhyperemic pressure ratios may overestimate CAD severity before aortic valve replacement.

Coronary Flow Reserve and Myocardial Resistance Reserve Changes After Transcatheter Aortic Valve Implantation in Aortic Stenosis

Aortic valve stenosis (AS) induces an alteration in hemodynamic conditions that are responsible for coronary microvasculature impairment. Relief of AS by transcatheter aortic valve implantation (TAVI) is expected to improve the coronary artery hemodynamic. We aimed to assess the midterm effects of TAVI in coronary flow reserve (CFR) and myocardial resistance reserve (MRR) by a continuous intracoronary thermodilution technique. At-rest and hyperemic coronary flow was measured by a continuous thermodilution technique in 23 patients with AS and compared with that in 17 matched controls, and repeated 6 ± 3 months after TAVI in 11 of the patients with AS. In patients with AS, absolute coronary flow at rest was significantly greater, and absolute resistance at rest was significantly less, than in controls (p <0.01 for both), causing less CFR and MRR (1.73 ± 0.4 vs 2.85 ± 1.1, p <0.01 and 1.95 ± 0.4 vs 3.22 ± 1.4, p <0.01, respectively). TAVI implantation yielded a significant 35% increase in CFR (p >0.01) and a 39% increase in MRR (p <0.01) driven by absolute coronary flow at rest reduction (p = 0.03). In patients with AS, CFR and MRR determined by continuous thermodilution are significantly impaired. At 6-month follow-up, TAVI improves these indexes and partially relieves the pathophysiologic alterations, leading to a partial restoration of CFR and MRR.

Kiosk 11R-TA-08 - The Breathing-induced Myocardial Oxygenation Reserve as a Marker for Vascular Function in Metabolic Syndrome

Kiosk 11R-TA-08 - The Breathing-induced Myocardial Oxygenation Reserve as a Marker for Vascular Function in Metabolic Syndrome

Coronary vascular function in females with history of hypertensive disorders of pregnancy an oxygenation-sensitive cardiovascular magnetic resonance imaging study

Abstract Background Hypertensive disorders of pregnancy (HDP), including gestational hypertension and preeclampsia, have been associated with increased risk for cardiovascular disease decades after HDP pregnancy. HDP is thought to unmask pre-existing cardiovascular risk in the mother; and in addition HDP triggers a cascade of inflammatory and oxidative stress which leads to vascular endothelial dysfunction and abnormalities in cardiac structure and function evident early post-partum that may persist sub-clinically. Oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) is an emerging approach that can identify dynamic changes of myocardial oxygenation as a marker for coronary vascular function. The objective of this study was to assess coronary vascular function in females with history of HDP using OS-CMR. Methods We analyzed data from two short axis OS-CMR slices in 20 females with history of HDP, including gestational hypertension, preeclampsia and HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets) and 20 healthy controls with history of normal pregnancy acquired on a 1.5T MRI scanner. Images were analyzed using a prototype tissue oxygenation module. The images were normalized for signal intensity to both ventricular blood pools. We used both traditional statistics and feature selection machine learning algorithms to select for predictive biomarkers in the dataset. Finally, we used a random forest classifier model for disease classification. We report area under the receiver operating curve (AUROC) as a metric for diagnostic accuracy. Results Global breathing-induced myocardial oxygenation reserve (B-MORE) of the mid left ventricular slice was significantly reduced in HDP females (-1.6 ± 14.8) when compared to healthy controls (11.3 ± 17.2, p=0.03), when normalized to ventricular blood pools (Figure 1A). Our feature selection algorithm selected the signal intensity during end-systole normalized to the series as the most predictive biomarker. Our model, which integrated data from &amp;gt;3,300 discrete data points per participant, correctly differentiated healthy controls from women with HDP history with a 90% ± 3% AUROC accuracy, indicating high sensitivity and specificity (Figure 1B). Conclusion Compared to healthy controls, females with history of HDP have abnormal coronary vascular function, as shown by reduced myocardial oxygenation on OS-CMR. Combining advanced machine learning approaches can further enhance the potential application of OS-CMR to risk stratify females with adverse pregnancy outcomes susceptible to future cardiovascular disease.

Abstract 13332: Assessment of Myocardial Oxygenation Response to Vasoactive Breathing Maneuvers in Patients With Repaired Dextro-Transposition of the Great Arteries an OS-CMR Study

Introduction: Long-term outcomes of patients with repaired Dextro-transposition of the great arteries (D-TGA) by arterial switch operation (ASO) are excellent. However, studies have suggested impaired myocardial blood flow reserve. Oxygen-sensitive cardiac magnetic resonance (OS-CMR) with vasoactive breathing maneuvers (BM) offers a contrast-free tool for evaluating myocardial oxygenation. Hypothesis: Evaluate myocardial oxygenation reserve and microvascular function in repaired D-TGA post-ASO using OS-CMR with BM. Methods: In this single-center study, we analyzed OS-CMR images (basal and mid-left ventricular slices) of 9 D-TGA post-ASO patients (mean age 29 ±6.52yrs, 33.3% females) and 10 healthy participants (mean age 33 ±8.9 yrs, 40% females) who completed the BM. The BM consisted of free breathing, then hyperventilation, causing vasoconstriction, then breath hold, causing vasodilatation. End-systolic OS-CMR signal intensity (SI) was measured at baseline, after hyperventilation (closest to 0 sec of breath hold), and at closest to 30 sec of breath hold. Changes in SI (ΔSI) in % were calculated in response to the different periods and compared using independent samples t-test. Results: In the D-TGA cohort, the coronary response to hyperventilation was abnormal compared to healthy subjects (5.8±19.9% vs -15.1±13.3%, p=0.01). No difference was observed in ΔSI% during breath hold (mean TGA:3.0±10.5% vs mean healthy:5.7±6%, p=0.5). No differences were observed in mid-slices for either period. Conclusions: Our findings suggest patients with D-TGA may have an impaired vasoconstrictor response to a hyperventilation maneuver. Further studies should explore the associated pathophysiology and potential impact on clinical management.

Abstract 16374: Perm1 Regulates Mitochondrial Energetics Through O-Glcnacylation in Cardiomyocytes

O-GlcNAcylation is a post-translational modification of proteins that plays an important role in cellular homeostasis and stress responses. Two enzymes regulate O-GlcNAcylation: O-GlcNAc transferase (OGT) that adds O-GlcNAc to proteins; O-GlcNAcase (OGA) that removes O-GlcNAc from proteins. While O-GlcNAcylation is necessary to respond to ischemia/reperfusion injury, chronic activation of O-GlcNAcylation in the heart has adverse effects, and excessive O-GlcNAcylation leads to the development of heart failure. However, there is currently no therapy for heart failure that targets O-GlcNAcylation. Perm1 is a striated muscle-specific regulator of mitochondrial bioenergetics. We previously demonstrated that Perm1-knockout mice exhibit reduced cardiac function and myocardial energy reserve, in association with excessive O-GlcNAcylation and upregulation of OGT. Here, we hypothesized that Perm1 maintains mitochondrial energetics by suppressing O-GlcNAcylation. We found that adenovirus-mediated overexpression of Perm1 in cardiomyocytes significantly decreased O-GlcNAcylation (Figure 1A-B) and increased the basal and maximal respiration and ATP production rates as compared with control in Cell Mito Stress Test using a Seahorse 96x flux analyzer (orange vs. green, Figure 1C-D). Furthermore, the increased levels of O-GlcNAcylated proteins (215% of control, p&lt;0.05) via silencing OGA (si-OGA) in cardiomyocytes significantly decreased the basal and maximal respiration capacity and ATP production rates as compared with control (green vs. purple, Figure 1C-D), all which were completely rescued by Perm1 overexpression (blue, Figure 1C-D). These results suggest that Perm1 positively regulates mitochondrial energetics, in part, via suppressing O-GlcNAcylation and that Perm1 might be a new therapeutic target of heart failure that maintains mitochondrial function through preventing excessive O-GlcNAcylation under pathological stress.

Use of Mechanical Circulatory Support in Complex High-risk Percutaneous Coronary Intervention: A Review of Current Evidence

With advances in devices and techniques of percutaneous coronary intervention (PCI), interventional cardiologists are managing patients with coronary artery disease of increasing complexity. For patients with prohibitive operative risk or who refuse bypass surgery, PCI may provide a reasonable alternative. Procedural haemodynamic stress often poses a significant challenge and is poorly tolerated in patients with reduced myocardial reserve, such as those with advanced heart failure or extreme frailty. The emergence of new mechanical circulatory support (MCS) devices has made PCI a more viable option for these high-risk patients. In this article, the authors review the existing evidence on the use of MCS in non-emergency complex and high-risk PCI, the optimal timing of initiating MCS and barriers to MCS use.

Стан толерантності до фізичного навантаження та характеристика міокардіальних резервів у дітей, які перенесли COVID-19

Assessment of the state of exercise tolerance (ET) after the transfer of COVID-19 is necessary to determine the long-term consequences of the coronavirus disease. Purpose - to assess the state of ET and analyze changes in myocardial reserve indicators in children who have experienced COVID-19 of varying degrees of severity. Materials and methods. 155 school-age children took part in the study. 120 children with a confirmed diagnosis of COVID-19 in the anamnesis and a period after COVID-19 of more than 12 weeks (main group) and 35 healthy children who did not suffer from COVID-19 (control group). The Group I (n=49) included children who contracted mild COVID-19; the Group II (n=40) - children who suffered from COVID-19 of moderate severity, the Group III (n=31) - children who contracted COVID-19 with a severe course. General clinical, instrumental (cycle ergometry), and statistical research methods were used. Results. In the main group, the average value of maximum oxygen consumption (VO2max) was 26.86±6.69 ml/kg/min, and in the control group - 38.29±5.54 ml/kg/min (p&lt;0.001). The analysis of this indicator in the Groups I, II, and III showed that transferred COVID-19 affects the level of ET in boys regardless of the severity of COVID-19 (p&lt;0.01). In girls, reduced ET was determined in the case of moderate and severe course of COVID-19. The analysis of myocardial reserves indicators showed that among children who fell ill with COVID-19, the worst indicators were observed in the Groups II and III (p&lt;0.01). Conclusions. Transmitted COVID-19 affects the state of ET and indicators of myocardial reserves in children in the period more than 12 weeks after COVID-19. The level of changes in the state of ET, values of the cardiac and vascular component of physical load support, and myocardial reserves depend on the degree of severity of the transferred COVID-19, which is confirmed by correlations of varying strength between these indicators and the degree of severity of COVID-19. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Cardiovascular impact of near complete estrogen deprivation in premenopausal women with breast cancer: The CROWN study

Survival with operable breast cancer has improved markedly in recent decades, however, treatment-related cardiovascular toxicities threaten to offset these gains. Ovarian function suppression paired with aromatase inhibition, for premenopausal women with hormone receptor (HR)-positive breast cancer, is a newer widely adopted therapy with the potential for significant long-term cardiovascular toxicity. Abrupt estrogen deprivation for non-cancer reasons is associated with accelerated coronary artery disease. Women with breast cancer treated with aromatase inhibition in addition to ovarian function suppression experience a dual hit with regards to estrogen exposure. The CaRdiac Outcomes With Near-complete estrogen deprivation (CROWN) study seeks to understand the early, subclinical natural history of cardiovascular compromise in young women undergoing near-complete estrogen deprivation (NCED) therapy. It is critical to understand the early subclinical development of cardiovascular disease to identify a window for therapeutic intervention before overt cardiovascular events occur. This three-site regional study (Atrium Health Wake Forest, Duke, and Virginia Commonwealth University) uses serial stress cardiac magnetic resonance (CMR) imaging and cardiac computed tomography angiography (CCTA) obtained during the initial two years of NCED therapy to study myocardial prefusion reserve (MPR), large cardiovascular vessel changes, left ventricular function, and other cardiovascular parameters. The CROWN cohort will consist of 90 premenopausal women with breast cancer, 67 with HR-positive disease receiving NCED and 23 comparators with HR-negative disease. Participants will undergo three annual CMR scans and two CCTA scans during the two-year study period. After initial activation hurdles, accrual has been brisk, and the study is expected to complete accrual in December 2024. Efforts are in place to encourage participant retention with the study primary outcome, change in MPR between the two groups, to be reported in 2026-2027. The results of this study will enable premenopausal women with breast cancer to balance the health burdens of cancer at a young age and treatment-related cardiovascular morbidity. Finally, the tools developed here can be utilized to study cardiovascular risk across a range of cancer types and cancer therapies with the ultimate goals of both developing generalizable risk stratification tools as well as validating interventions which prevent overt cardiovascular compromise.

Triple Vessel Coronary Artery Disease Needs a Consistent Definition for Management Guidelines

For over forty years, coronary artery bypass grafting (CABG) has been recommended to patients with triple vessel disease (TVD) with the aim of providing a survival benefit compared to medical therapy. Generally, the survival benefit of CABG is determined by (a) the volume of myocardium at risk of infarction according to the extent of coronary artery disease (CAD), (b) the impairment of coronary flow reserve according to severity of coronary stenoses, severity of symptoms, or objective evidence of regional ischemia, and (c) the impairment of myocardial reserve according to left ventricular function and viability. The most frequently used index of survival benefit is the extent of CAD as described by the terms of the left main coronary stenosis and TVD. However, TVD has been inconsistently defined in randomised controlled trials. Furthermore, international guidelines do not provide a specific definition of TVD. This impacts a substantially sized and high-risk population. Here, we argue that the definition of TVD should include diseases in the major artery in each of the three coronary territories in order to estimate the survival benefit provided by CABG.

Microvascular Dysfunction as a Possible Link Between Heart Failure and Cognitive Dysfunction.

Microvascular function in the brain and heart may play an important role in the course of patients with heart failure (HF), but its relationship with ventricular and cognitive function is not well understood. We hypothesized that microvascular function in HF is closely related to both, cardiac and cognitive function. In healthy controls and symptomatic patients with HF (New York Heart Association functional class II or III), we used oxygenation-sensitive magnetic resonance imaging during a standardized breathing maneuver to determine the cerebral oxygenation reserve and the myocardial oxygenation reserve (MORE) as markers for microvascular function. A stepwise multivariable linear regression was performed to determine the variables that best predict changes in cerebral oxygenation reserve and MORE. We also measured cognitive function using the Montreal Cognitive Assessment test. Twenty patients with HF (age 64.4±8.3 years; 50% female sex), and 21 healthy controls (age 55.0±5.1 years; 62% female sex) were included in the analysis. In patients with HF, cerebral oxygenation reserve and MORE were lower than in healthy controls (MORE, -0.1±3.3 versus 5.0±4.2, cerebral oxygenation reserve: 0.43±0.47 versus 1.21±0.60, respectively) as were Montreal Cognitive Assessment score results (HF, 23.9±3.7; healthy, 27.8±1.5; P=0.002). The Montreal Cognitive Assessment score in patients was correlated with cardiac output (r=0.55, P=0.011) and MORE (r=0.46, P=0.040). In addition to the presence of HF, significant predictors of cerebral and myocardial oxygenation reserve were cardiac output and end-diastolic volume, respectively. Our results indicate that heart failure is an independent predictor of coronary and cerebral microvascular dysfunction as defined by a reduced response to a vasodilatory breathing maneuver. This impaired response was associated with reduced cognitive function.

Амплитудные показатели ЭКГ у мужчин разного возраста при субмаксимальной физической нагрузке (на примере жителей Европейского Севера России)

The purpose of this study was to investigate the effect of submaximal physical activity (PWC170 test) on electrocardiogram (ECG) amplitude parameters in men of different ages. Materials and methods. The research involved apparently healthy men aged 20–29 (n = 27) and 40–49 (n = 27) years living in the European North of Russia. They performed a bicycle ergometer PWC170 test with incrementally increasing 3-minute loads (50, 100 and 150 W) and ECG recording in the Nehb leads. Results. A and D leads showed the most informative dynamics of ECG parameters in the subjects during the exercise test. It was mainly expressed in an increase in P wave amplitude, a decrease in T wave amplitude, a deepening of the S wave, and ST segment depression. The group of 40–49-year-old men, compared to 20–29-year-olds, was characterized by less pronounced T wave (lead D) amplitude changes at the beginning of the test, a less deep S wave (lead I), no shift in the ST segment (lead D) as well as a smaller number of parameters that showed statistically significant changes in the exercise test. ST segment (lead A) depression during the final load was twice as common in the older group of men (13 % in 20–29-year-olds and 25 % in 40–49-year-olds). Heart rate (HR) at all stages of the test, except for the last one, was lower in 40–49-year-olds; however, its more significant increase by the end of the test eliminated the statistical differences in HR at the final stage and in physical work capacity (PWC170) between the groups. The revealed differences in ECG and HR parameters may be associated with morphological changes occurring in the cardiovascular system with age, in particular, with the decrease in left ventricular function. Submaximal physical activity in men of the older age group involves a greater expenditure of myocardial reserves.

Comparison between Myocardial Glycogen Storage in CABG after Using Blood Cardioplegia versus HTK Solution

Abstract Background Inadequate myocardial protection in long ischaemic periods followed by reperfusion is an issue of concern in cardiac surgery. Cardioplegic solutions improve the tolerance to ischaemia and reperfusion by preserving myocardial energy reserves, preventing osmotic and electrolyte imbalances and buffering acidosis. Objective This somewhat surprising given the high number of procedures performed worldwide with this cardioplegic solution. As such, the purpose of this study was to assess the safety of the HTK solution when compared with our standard blood cardioplegia in coronary artery bypass graft operations via assessment of myocardial glycogen storage. Patients and Methods This was a retrospective, convenient, non- randomized study conducted on 40 consecutive patients who underwent isolated elective CABG at department of cardiothoracic surgery at Ain Shams University Hospitals. The aim of the study was to compare early outcomes of Custodiol versus blood cardioplegia in coronary artery bypass graft surgery via assessment of glycogen storage in myocarduim via assessment of myocardial glycogen storage. at Ain Shams University Hospitals. Results There was no statistically significant difference between the two groups of myocardial glycogen storage post-operative. Conclusion There was statistically significant difference between the pre and post-operative in both custodial and blood cardioplegia. There was no statistically significant difference between the two groups of myocardial protection in mortality and morbidity. Custodiol cardioplegia is an easy technique and simple without need of preparation or repeated administration.

Functional reserve and contractile phenotype of atrial myocardium from patients with atrial remodeling without and with atrial fibrillation.

Atrial contractility and functional reserve in atrial remodeling (AR) without (AR/-AF) or with atrial fibrillation (AR/+AF) are not well characterized. In this study, functional measurements were performed in right atrial muscle strips (n = 71) obtained from patients (N = 22) undergoing routine cardiac surgery with either no AR [left atrial (LA) diameter < 40 mm and no history of AF (hAF)], AR/-AF (LA diameter ≥ 40 mm, no hAF), or AR/+AF (hAF and LA diameter ≥ 40 mm or LAEF < 45%). AR/-AF and AR/+AF were associated with a prolongation of half-time-to-peak (HTTP, P < 0.001) and time-to-peak (TTP) contraction (P < 0.01) when compared with no AR. This effect was seen at baseline and during β-adrenergic stimulation with isoproterenol (Iso). Early relaxation assessed by half-relaxation time (HRT) was prolonged in AR/-AF (P = 0.03) but not in AR/+AF when compared with no AR at baseline, but this delay in relaxation in AR/-AF was attenuated with Iso. Late relaxation (τ) did not differ between AR/-AF and no AR but was consistently shorter in AR/+AF than no AR before (P = 0.04) and during Iso (P = 0.01), indicating accelerated late relaxation in AR/+AF. Relative force increase during Iso was higher (P = 0.01) and more dispersed (P = 0.047) in patients with AR/+AF. Relative adrenergic response was unaltered in the myocardium of patients with AR/-AF and AR/+AF. In conclusion, AR/-AF and AR/+AF are associated with changes in myocardial inotropic reserve and contractility. The changes are particularly pronounced in patients with AR/+AF, suggesting that the progression from AR/-AF to AR/+AF is associated with progressive alterations in atrial function that may contribute to arrhythmogenesis.NEW & NOTEWORTHY Mechanical alterations in atrial remodeling without (AR/-AF) and with atrial fibrillation (AR/+AF) have not been studied in detail in human atrial tissue preparations. To our knowledge, this is the first study to compare the mechanical phenotype and inotropic reserve in human atrial myocardial preparations from patients with no atrial remodeling, AR/-AF, and AR/+AF. We identify specific patterns of contractile dysfunction and heterogeneity for both, AR/-AF and AR/+AF, indicating the progression of atrial disease.

Splenic switch-off in regadenoson 82Rb-PET myocardial perfusion imaging: assessment of clinical utility

BackgroundSplenic switch-off (SSO) is a phenomenon describing a decrease in splenic radiotracer uptake after vasodilatory stress. We aimed to assess the diagnostic utility of regadenoson-induced SSO. MethodsWe included consecutive patients who had clinically indicated Regadenoson Rb-82 PET-MPI for suspected CAD. This derivation cohort (no perfusion defects and myocardial flow reserves (MFR) ≥ 2) was used to calculate the splenic response ratio (SRR). The validation cohort was defined as patients who underwent both PET-MPI studies and invasive coronary angiography (ICA). ResultsThe derivation cohort (n = 100, 57.4 ± 11.6 years, 77% female) showed a decrease in splenic uptake from rest to stress (79.9 ± 16.8 kBq⋅mL vs 69.1 ± 16.2 kBq⋅mL, P < .001). From the validation cohort (n = 315, 66.3 ± 10.4 years, 67% male), 28% (via SRR = 0.88) and 15% (visually) were classified as splenic non-responders. MFR was lower in non-responders (SRR; 1.55 ± 0.65 vs 1.76 ± 0.78, P = .02 and visually; 1.18 ± 0.33 vs 1.79 ± 0.77, P < .001). Based on ICA, non-responders were more likely to note obstructive epicardial disease with normal PET scans especially in patients with MFR < 1.5 (SRR; 61% vs 34% P = .05 and visually; 68% vs 33%, P = .01). ConclusionLack of splenic response based on visual or quantitative assessment of SSO may be used to identify an inadequate vasodilatory response.

Визначення толерантності до фізичного навантаження і резервів організму в дітей шкільного віку з ожирінням та артеріальною гіпертензією

Determining of tolerance to physical exertion (TPE) in children with various diseases is an important diagnostic aspect of modern medicine. This area helps to improve the prognostic capabilities of doctors and improve approaches to therapeutic interventions in patients with various pathologies. In pediatrics, there are limited data on the study of TPE in patients with hypertension and no data at all in children with a combination of hypertension and obesity. Purpose - to assess the level of TPE and body reserves in school-age children with obesity and arterial hypertension. Materials and methods. 112 patients aged 9-18 took part in the study. All patients were divided into four groups. The Group 1 (control) included children with normal blood pressure and normal body weight; the Group 2 included patients with arterial hypertension and normal body weight; the Group 3 - with normal arterial pressure and obesity; the Group 4 - with a combination of arterial hypertension and obesity. Results and conclusions. If patients have hypertension or obesity, a decrease in VO2max is noted, which is more pronounced when these pathologies are comorbid. Obese boys have a tendency to increase maximum systolic blood pressure during bicycle ergometry (158.2±8.4 mmHg) compared to healthy children (149.4±10.5 mmHg). The average values of maximum diastolic blood pressure during bicycle ergometry in all studied groups did not differ significantly from the average values of the control group. Obesity is accompanied by a more pronounced decrease in vascular reserves than arterial hypertension, the comorbidity of these diseases in patients is associated with the deterioration of these reserves in comparison with patients who have only one disease. The obtained results indicate a decrease in cardiac reserves when the patient has comorbidities of arterial hypertension and obesity. At the same time, the presence of only one of the named diseases in the patient is not accompanied by a significant decrease in indicators compared to the control group. In patients with arterial hypertension, a less effective use of myocardial reserves and an increased demand for myocardial oxygen during work compared to healthy children are noted. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Association of impaired myocardial flow reserve with risk factors for cardiovascular diseases in patients with nonobstructive coronary artery disease

Aim. To reveal the association between disorders of myocardial blood flow and reserve, according to dynamic single photon emission computed tomography (SPECT), with risk factors for cardiovascular diseases (CVD) in patients with nonobstructive coronary artery disease (CAD).Material and methods. The study included patients with suspected stable nonobstructive (&lt;50%) CAD. Based on the survey data, anamnesis, out- and in-patient medical records, we analyzed main CVD risk factors. All patients underwent dynamic myocardial SPECT and analysis of blood lipid profile in vitro. Depending on myocardial flow reserve (MFR), two groups were formed: 1. With reduced MFR &lt;2,0 (rMFR); 2. With normal MFR ≥2,0 (nMFR).Results. The study included 47 patients divided into 2 following groups: the rMFR group consisted of 24 patients (15 men, age 56,3±9,1 years), the nMFR group — 23 patients (13 men, age 58,4±10,7 years). There was no significant difference in prevalence of CVD risk factors in groups. However, dyslipidemia was detected more often in rMFR patients (p=0,053): 58% vs 30%, respectively. In patients with rMFR, there were significantly higher levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). Correlation analysis revealed significant negative inverse relationships between MFR values with TC (ρ=-0,36, p=0,01) and LDL-C (ρ=-0,38, p=0,009). According to univariate logistic regression, significant predictors of reduced MFR were TC (odds ratio (OR), 2,32; 95% confidence interval (CI), 1,17-4,59; p=0,01) and LDL-C (OR, 2,16; 95% CI, 1,04-4,51; p=0,04). According to a stepwise multivariate logistic regression analysis, only TC was an independent predictor of a decrease in MFR (OR, 2,32; 95% CI, 1,17-4,59; p=0,02).Conclusion. MFR, determined by dynamic SPECT, is associated with TC and LDL-C levels. TC level is an independent predictor of a decrease in MFR.