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This study presents electrical modelling of the arterial system to understand the effect of adrenaline on the aortae and small arteries in terms of their resistance and compliance. There is no categorical documentation in the current literature on the precise locations of arterial resistance (R) and compliance (C) in vasculature. Knowledge of their exact locations in the arterial tree enables re-assessment of the differential action of vasoactive drugs on resistance versus compliance vessels once we resolve beat-to-beat changes in R and C in response to these drugs. Isolated goat aortae and small arteries were perfused with a pulsatile pump and lumen pressures were recorded before and after addition of adrenaline. Equivalent electrical models were simulated, and biological data was compared against the electrical equivalents to derive interpretations. In the aortae, systolic pressure increased, diastolic pressure decreased, pulse pressure increased (P = .018); but the mean pressure remained the same (P = .357). Whereas in small artery, vasoconstriction caused an increase in systolic, diastolic, and mean pressures (P = .028). Simulations allow us to infer that vasoconstriction in the aorta leads to a reduction in compliance, but an increase in resistance if any, is not sufficient to alter the mean aortic pressure. Whereas vasoconstriction in small arteries increases resistance, but a decrease in compliance, if any, does not affect any of the pressure parameters measured. The presented study is first of its kind to give experimental evidence that large arteries and aorta are the only compliance vessels and small arteries are the only resistance vessels.

BACKGROUND The VentriFlo® True Pulse Pump (VentriFlo, Inc, Pelham, NH, USA) is a new pulsatile blood pump intended for use during short-term circulatory support. The purpose of this study was to evaluate the feasibility of the VentriFlo and compare it to a conventional centrifugal pump (ROTAFLOW, Getinge, Gothenberg, Sweden) in acute pig experiments. METHODS Pigs (40-45 kg) were supported by cardiopulmonary bypass (CPB) with the VentriFlo (n = 9) or ROTAFLOW (n = 5) for 6 h. Both VentriFlo and ROTAFLOW circuits utilized standard CPB components. We evaluated hemodynamics, blood chemistry, gas analysis, plasma hemoglobin, and microcirculation at the groin skin with computer-assisted video microscopy (Optilia, Sollentuna, Sweden). RESULTS Pigs were successfully supported by CPB for 6 h without any pump-related complications in either group. The VentriFlo delivered an average stroke volume of 29.2 ± 4.8 ml. VentriFlo delivered significantly higher pulse pressure (29.1 ± 7.2 mm Hg vs. 4.4 ± 7.0 mm Hg, p

OBJECTIVES The objective of this in vitro study was to compare Doppler versus catheter transvalvular pressure gradients (TPG) in third generations balloon-expandable (BE) versus self-expanding (SE) transcatheter heart valves (THV). BACKGROUND TPG is a key parameter to assess and follow valve hemodynamic function following transcatheter aortic valve implantation (TAVI). It remains uncertain and debated whether, and to which extent, TPGs differ according to the type of THV, that is, BE versus SE and to the method used for TPG measurement, that is, Doppler echocardiography versus cardiac catheterization. METHODS The CoreValve EVOLUT PRO 26 mm and the SAPIEN 3 23 mm THVs were tested in a left heart simulator using a 21 mm aortic annulus under following conditions: heart rate: 70 bpm, mean aortic pressure: 100 mmHg, stroke volume: 30, 70 and 100 ml. Mean TPGs were measured by continuous-wave Doppler and by micro-tip pressure catheters positioned in the left ventricle and at 50 mm downstream to the tip of the THV leaflets. RESULTS Doppler TPGs (9.5 ± 3.9 mmHg) were on average 40.5 ± 13.9% higher (p

Artificial organs 46(1), 71-82 (2022). doi:10.1111/aor.14042, Published by Wiley-Blackwell, Oxford [u.a.]

Background This study evaluated the mechanism of decline in coronary pressure from the proximal to the distal part of the coronary arteries in the left anterior descending (LAD) versus the right coronary artery (RCA) from the insight of coronary hemodynamics using wave intensity analysis (WIA). Methods Twelve patients with angiographically normal LAD and RCA were prospectively enrolled. Distal coronary pressure, mean aortic pressure, and average peak velocity were measured at 4 different positions: 9, 6, 3, and 0 cm distal from each coronary ostium. Results The distal-to-proximal coronary pressure ratio during maximum hyperemia gradually decreased in proportion to the distance from the ostium (0.92±0.03 and 0.98±0.03 at 9 cm distal to the LAD and RCA ostium). WIA showed the dominant forward-traveling compression wave gradually decreased and the backward-traveling suction wave gradually decreased in proportion to the decrease in coronary pressure through the length of the non-diseased LAD but not the RCA. Conclusions The pushing wave and suction wave intensities on WIA were diminished in proportion to the distance from the ostium of the LAD despite the wave intensity not changing across the length of the RCA, which may lead to gradual intracoronary pressure drop in the angiographically normal LAD.

Background This study evaluated the early and intermediate-term clinical and hemodynamic results after implant of the Medtronic 3F (Minneapolis, MN) stentless aortic valve. Methods Between March 2007 and August 2015, 226 consecutive patients affected by aortic valve disease received a 3F valve at our unit by a single surgeon. The valve in 30 patients was included in a tubular prosthesis for a Bentall procedure. Size ranged between 21 and 29, age at operation was 74.17 ± 8.58 years, mean logistic European System for Cardiac Operative Risk Evaluation was 9.73 ± 6.00, and 51.3% of patients received a concomitant procedure. For isolated valve replacement, mean extracorporeal circulation time was 92 ± 17 minutes, and cross-clamp time was 73 ± 11 minutes. Follow-up was 100% complete and was a mean of 63 ± 2.4 months (range, 6-138 months). Primary end points were early and late mortality, freedom from endocarditis, freedom from structural valve deterioration, and freedom from valve-related reoperation. Results Early mortality after isolated aortic valve replacement was 1.7%. Of the 59 (25.3%) late overall deaths, 15 (6.6%) were cardiac-related, and survival rate was 93% at 10 years. At follow-up, 97% of patients were in New York Heart Association class I or II. Actuarial freedom from reoperation due to structural deterioration was 100% at 5 years and 96% at 10 years. Freedom from endocarditis at 10 years was 97%. Mean aortic pressure gradient measured by echocardiography was 11.5 mm Hg at hospital discharge and 10.4 mm Hg at the last follow-up. Conclusions The 3F valve is a user-friendly third-generation stentless aortic prosthesis with proven durability and remarkable hemodynamic performance preserved over time. The 3F is particularly useful in cases of expected patient/prosthesis mismatch

BACKGROUND Based on coronary angiography and mean aortic pressure, a specially designed computational flow dynamics (CFD) method is proposed to determine contrast fractional flow reserve (cFFR) without using invasive pressure wire. This substudy assessed diagnostic performance of coronary angiography-derived cFFR in catheterization laboratory, based on a previous multicenter trial for online assessment of coronary angiography-derived FFR (caFFR). METHODS Patients with diagnosis of stable angina pectoris or unstable angina pectoris were enrolled in six centers. Wire-based FFR was measured in coronary arteries with 30-90% diameter stenosis. Offline angiography-derived cFFR was computed in blinded fashion against the wire-based FFR and caFFR at an independent core laboratory. RESULTS A total of 330 patients were enrolled to fulfill inclusion/exclusion criteria from June 26 to December 18, 2018. Offline angiography-derived cFFR and wire-based FFR results were compared in 328 interrogated vessels. The statistical analysis showed the highest diagnostic accuracy of 89.0 and 86.6% for angiography-derived cFFR with a cutoff value of 0.94 and 0.93 against the wire-based FFR with a cutoff value of 0.80 and 0.75, respectively. The corresponding sensitivity and specificity were 92.2 and 87.3% for the cutoff value of 0.94 and 80.0 and 88.4% for the cutoff value of 0.93, which are similar to those against the caFFR. The receiver-operating curve has area under the curve of 0.951 and 0.972 for the wire-based FFR with the cutoff value of 0.80 and 0.75, respectively. CONCLUSIONS Coronary angiography-derived cFFR showed higher accuracy, sensitivity, and specificity against wired-based FFR and caFFR. Hence, angiography-derived cFFR could enhance the hemodynamic assessment of coronary lesions.

Long-term using continuous flow ventricular assist devices could trigger complications associated with diminished pulsatility, such as valve insufficiency and gastrointestinal bleeding. One feasible solution is to produce pulsatile flow assist with speed regulation in continuous flow ventricular assist devices. A third-generation blood pump with pulsatile operation control algorithm was first characterized alone under pulsatile mode at various speeds, amplitudes, and waveforms. The pump was then incorporated in a Mock circulation system to evaluate in vitro hemodynamic effects when using continuous and different pulsatile operations. Pulsatility was evaluated by surplus hemodynamic energy. Results showed that pulsatile operations provided sufficient hemodynamic assistance and increased pulsatility of the circulatory system (53% increment), the mean aortic pressure (65% increment), and cardiac output (27% increment). The pulsatility of the system under pulsatile operation support was increased 147% compared with continuous operation support. The hemodynamic performance of pulsatile operations is susceptible to phase shifts, which could be a tacking angle for physiological control optimization. This study found third-generation blood pumps using different pulsatile operations for ventricular assistance promising.

Rotary left ventricular assist devices (LVAD) have emerged as a long-term treatment option for patients with advanced heart failure. LVADs need to maintain sufficient physiological perfusion while avoiding left ventricular myocardial damage due to suction at the LVAD inlet. To achieve these objectives, a control algorithm that utilizes a calculated suction index from measured pump flow (SIMPF) is proposed. This algorithm maintained a reference, user-defined SIMPF value, and was evaluated using an in silico model of the human circulatory system coupled to an axial or mixed flow LVAD with 5–10% uniformly distributed measurement noise added to flow sensors. Efficacy of the SIMPF algorithm was compared to a constant pump speed control strategy currently used clinically, and control algorithms proposed in the literature including differential pump speed control, left ventricular end-diastolic pressure control, mean aortic pressure control, and differential pressure control during (1) rest and exercise states, (2) rapid, eight-fold augmentation of pulmonary vascular resistance for (1), and (3) rapid change in physiologic states between rest and exercise. Maintaining SIMPF simultaneously provided sufficient physiological perfusion and avoided ventricular suction. Performance of the SIMPF algorithm was superior to the compared control strategies for both types of LVAD, demonstrating pump independence of the SIMPF algorithm.

The benefit of TAVI in cancer patients is currently unclear. The purpose of this study is to investigate prognostic impact of cancer status (active cancer or previous cancer) in severe aortic stenosis (AS) patients undergoing transcatheter aortic valve implantation (TAVI). Consecutive TAVI patients in the Heart Center Bonn were enrolled and we stratified the patients into three groups: current cancer (active cancer), non-current cancer (previous cancer), or no cancer. The primary outcome was all-cause death within a 5-year follow-up. We evaluated mean aortic pressure gradient (mPG) values following TAVI (baseline mPG) and at the final follow-up (follow-up mPG). In total, 1568 TAVI patients were eligible and 298 patients (19.0%) had active or previous cancer. At the 5-year follow-up, cancer patients had a significantly worse prognosis than non-cancer patients (log rank, P

Aims We hypothesized that among patients with low-gradient severe aortic stenosis (AS) and preserved left ventricular ejection fraction (LVEF), reclassification of AS severity as moderate by pressure recovery adjusted indexed aortic valve area (AVAi) = energy loss index (ELI), may identify a subgroup of patients with a better outcome. Methods and results Three hundred and seventy-nine patients with low-gradient AS (defined by AVAi ≤ 0.6 cm2/m2 and mean aortic pressure gradient 0.6 cm2/m2. Cardiac events [cardiac mortality and/or need for aortic valve replacement (AVR)] during follow-up were studied. One hundred and forty-eight patients (39%) were reclassified as moderate AS by ELI. Reclassification as moderate AS was independently associated with decreased body surface area, normal flow status, decreased left ventricular mass index, and left atrial volume index (all P Conclusion In patients with low-gradient severe AS and preserved LVEF, calculation of ELI permits to reclassify almost 40% of patients as having moderate AS. These reclassified patients have a considerable reduction of the risk of cardiac events during follow-up. Calculation of ELI is useful for decision-making in patients with low-gradient severe AS and preserved ejection fraction.

Degenerative aortic valve stenosis is an inflammatory process that resembles atherosclerosis. Neutrophils release their DNA upon activation and form neutrophil extracellular traps (NETs), which are present on degenerated aortic valves. NETs correlate with pressure gradients in severe aortic stenosis. Transcatheter aortic valve replacement (TAVR) is an established treatment option for aortic valve stenosis. Bioprosthetic valve deterioration promoted by inflammatory, fibrotic and thrombotic processes limits outcome. Deoxyribonuclease is a natural counter mechanism to degrade DNA in circulation. In the present observational study, we investigated plasma levels of double-stranded DNA, deoxyribonuclease activity and outcome after TAVR. 345 consecutive patients undergoing TAVR and 100 healthy reference controls were studied. Double-stranded DNA was measured by fluorescence assays in plasma obtained at baseline and after TAVR. Deoxyribonuclease activity was measured at baseline using single radial enzyme diffusion assays. Follow-up was performed at 12 months, and mean aortic pressure gradient and survival were evaluated. Receiver operating characteristic, Kaplan-Meier curves and Cox regression models were calculated. Baseline double-stranded DNA in plasma was significantly higher compared to healthy controls, was increased at 3 and 7 days after TAVR, and declined thereafter. Baseline deoxyribonuclease activity was decreased compared to healthy controls. Interestingly, low deoxyribonuclease activity correlated with higher C-reactive protein and higher mean transaortic gradient after 12 months. Finally, deoxyribonuclease activity was a strong independent predictor of outcome 12 months after TAVR. Deoxyribonuclease activity is a potential biomarker for risk stratification after TAVR. Pathomechanisms of bioprosthetic valve deterioration involving extracellular DNA and deoxyribonuclease merit investigation.

Although the left coronary artery (LCA) has a flow profile in that most blood flow occurs during diastole rather than systole, the right coronary artery (RCA) has a flow pattern that is less diastolic dominant. This study assessed whether coronary pressure waveforms distal to stenoses with the same fractional flow reserve (FFR) was the same between the LCA and RCA. A total of 347 vessels from 318 patients who underwent FFR measurements were included. Conventional FFR was calculated as the ratio of the mean coronary distal pressure (Pd) to the mean aortic pressure (Pa) at maximal hyperemia. The pressure drop ratios in systole (PDRsystole) and diastole (PDRdiastole) were calculated as the sum of (Pa minus Pd) divided by the sum of Pa at the intracoronary diastolic and systolic pressure phases, respectively. Analysis of covariance of the regression line of correlation between conventional FFR and PDRsystole revealed that the slope was significantly greater in the RCA than in the left anterior descending artery (LAD) and left circumflex artery (LCX) (−0.765, −0.578, and −0.589, p

Vasoconstriction in small arteries and arterioles is known to increase resistance to flow, while vasoconstriction in large arteries and aorta is known to decrease their compliance. Besides this general understanding, there is no systematic documentation on what happens to small artery compliance and large artery resistance during vasoconstriction and the corresponding alterations in vascular pressure. The aim of the study is to assess the effect of adrenaline on goat aortae and small arteries in terms of resistance and compliance.Isolated goat aortae and small arteries were perfused with a pulsatile pump and lumen pressure was recorded before and after addition of adrenaline. In the aortae, systolic pressure increased, diastolic pressure decreased, pulse pressure increased (p = 0.018, WSR); but the mean pressure remained the same (p = 0.357, WSR). Small artery vasoconstriction caused an increase in systolic, diastolic and mean pressures (p = 0.028, WSR). Using length, radius, and thickness data from the tissues and the tubes of the experimental set-up, electrical models were simulated to understand the biological data. The simulations allow us to infer that vasoconstriction in aorta leads to a reduction in compliance, but an increase in resistance if any, is not sufficient to change the mean aortic pressure. On the other hand, vasoconstriction in small arteries increases resistance, but a decrease in compliance if any, does not affect any of the four pressure parameters measured. Vasoconstriction in aorta decreases compliance and therefore increases pulse pressure but does not change resistance significantly enough to alter mean pressure.Key Points SummaryThe main aim of the study is to understand where exactly resistance (R) and compliance (C) components of the vasculature occur. There is no definitive evidence for the effect of large artery vasoconstriction on resistance and hence the mean arterial pressure.The manuscript presents biological experiments studying the pressure response of goat aorta and small arteries to adrenaline (invitro) and the interpretations using equivalent electrical models.The study shows that in aorta and large arteries, vasoconstriction does not lead to a reduction in lumen diameter sufficient to cause a rise in resistance and mean pressure as compared to small arteries.Knowledge of exact location of R and C in the arterial tree enables re-assessment of the differential action of vasoactive drugs on resistance versus compliance vessels once we resolve beat-to-beat R and C changes in response to a drug. This way antihypertensive therapy can be tailored to address the specific cause of the type of hypertension.

Objectives Small Aortic Annulus (AA) is big issue during Aortic Valve Replacement (AVR) necessitating replacement of inappropriate-sized prostheses especially during Double Valve Replacement (DVR). Despite that small aortic valve prostheses can lead to Prosthesis-Patient Mismatch (PPM), there remains reluctance to perform aortic root enlargement (ARE) procedures fearing from morbidity and mortality. We evaluate clinical and echocardiographic outcomes in patients with small AA undergoing DVR. Methods The study included 100 consecutive patients underwent DVR for combined rheumatic aortic and mitral valve diseases, between June 2016 and November 2020. Only (50) patients had ARE with DVR. ARE was performed using an autologous or bovine pericardium or Dacron patch by Nick′s or Manouguian procedures. The estimated post-operative end-points were mortality, effective orifice areas (EOA), mean aortic pressure gradient and valve-related complications. The least post-operative follow-up period was 6 months. Results The study included 30 male and 70 female patients with mean age of 45 ± 10 years, body surface area (BSA) of 1.6 ± 0.50 m2, aortic annulus diameter was 20 ± 0.4 mm, EOAi was 0.80 ± 0.50 cm2/m2, and aortic mean gradient (PG) 80 ± 40 mm Hg. During follow-up period, there was a mild paravalvular leak (1%) with, (1%) heart block, and residual mean PG on prosthetic aortic valve with all cases of DVR alone. Conclusion Enlargement of aortic root by Nick′s or Manouguian technique is safe and effective in patients with small aortic annulus undergoing double valve replacements.

Study Objectives: The objective of this study is to assess the feasibility of using a disposable pressure transducer to obtain mean aortic pressure (MAP) during CPR and placement of resuscitative endovascular balloon occlusion of the aorta (REBOA) within an emergency medicine (EM)-initiated multi-disciplinary protocol in non-traumatic out-of-hospital cardiac arrest (OHCA) Methods: During medical cardiac arrest obtaining a MAP >55 mmHg has been associated with greater survivorship Use of an arterial line and monitor requires calibration which may demand additional personnel resources during management of a cardiac arrest A disposable pressure transducer (Centurion Compass® Pressure Monitor) is able to detect and display mean aortic pressure within seconds of placement onto an arterial line We are conducting a single-arm early feasibility study of REBOA initiated in the emergency department (ED) for OHCA using an Food and Drug Administration (FDA) investigational device approval with an exception from informed consent During this study we are evaluating the feasibility of using disposable pressure transducers to determine MAP during CPR and REBOA placement Our goal is to enroll 20 patients as part of this feasibility study Results: Two of the initial twenty patients were enrolled between January and February 2020, with a temporary pause in enrollment due to the COVID pandemic from March to July 2020 A disposable pressure transducer was used to obtain continuous MAPs in both patients Our initial patient was a 77-year-old man who presented in refractory ventricular fibrillation and we were able to obtain pre- and post- REBOA inflation MAPs After inflation of the aortic balloon, investigators noted immediate improvements in mean aortic pressure (MAP) (37 to 50 mmHg) The second patient, a 63-year-old man, underwent successful REBOA placement with similar improvements in MAP (22 to 50 mmHg) Investigators were also able to identify large differences in MAPs generated between individuals performing CPR, noting MAPs between 34 and 50 between multiple CPR providers despite visually adequate chest depth compressions Conclusion: The use of disposable pressure transducers during CPR and REBOA in OHCA to rapidly obtain MAP may be feasible Further, use of these transducers may assist in guiding CPR to achieve target MAPs during cardiac arrest More research is needed to determine what impact a targeted MAP has on patient outcomes, and whether or not it correlates with changes in end-tidal carbon dioxide (ETCO2)

The use of fractional flow reserve (FFR) in guiding revascularisation improves patient outcomes and has been well-established in clinical guidelines. Despite this, the uptake of FFR has been limited, likely attributable to the perceived increase in procedural time and use of hyperaemic agents that can cause patient discomfort. This has led to the development of instantaneous wave-free ratio (iFR), an alternative non-hyperaemic pressure ratio (NHPR). Since its inception, the use of iFR has been supported by an increasing body of evidence and is now guideline recommended. More recently, other commercially available NHPRs including diastolic hyperaemia-free ratio and resting full-cycle ratio have emerged. Studies have demonstrated that these indices, in addition to mean distal coronary artery pressure to mean aortic pressure ratio, are mathematically analogous (with specific nuances) to iFR. Additionally, there is increasing data demonstrating the equivalent diagnostic performance of alternative NHPRs in comparison with iFR and FFR. These NHPRs are now integral within most current pressure wire systems and are commonly available in the catheter laboratory. It is therefore key to understand the fundamental differences and evidence for NHPRs to guide appropriate clinical decision-making.

Background Bioprosthesis has been increasingly implanted for the treatment of transvalvular disease across the world. A new Dafodil™ pericardial bioprosthesis (Meril Life Sciences Pvt. Ltd., India) recently approved by Conformité Européenne (CE) is a tri-leaflet, stented, bovine valve. The purpose of Dafodil-1 first-in-human trial was to evaluate clinical safety and performance (including hemodynamic parameters) of the Dafodil pericardial bioprosthesis in patients who underwent aortic or mitral valve replacement. Methods This prospective, multicenter clinical trial enrolled 60 patients (Aortic: 30 patients; Mitral: 30 patients) from seven sites across India. Safety endpoints were early (≤30 days) and late (> 30 days) mortality and valve-related morbidity. The performance endpoints were hemodynamic performance, improvement in NYHA functional class, and change in the quality of life using SF-12v1 health survey. Results From July 2017 to July 2018, 60 patients underwent implantation of the Dafodil pericardial bioprosthesis. Post-operatively, NYHA functional class significantly improved in all the patients (Aortic: 90% NYHA class-I and 10% NYHA class-II; Mitral: 96.55% NYHA class-I and 3.45% NYHA class-II; P 2 effective orifice area (EOA)] pre-operatively to 14.49 ± 6.58 mmHg (EOA: 1.85 ± 0.27 cm2) at 12-month. Overall, the mitral mean pressure gradient and EOA were 4.41 ± 1.69 mmHg and 2.67 ± 0.48 cm2, respectively, at 12-month. Significant improvement (P Conclusions The clinical safety and performance of the Dafodil pericardial bioprosthesis were favourable at 12-month. Moreover, a study with a larger patient population and longer follow-up is warranted to further assess the device. Trial registration Dafodil-1 trial has been prospectively registered on 10/07/2017 under Clinical Trial Registry-India (http://www.ctri.nic.in). (Registration number: CTRI/2017/07/009008).

Although current guidelines generally recommend watchful waiting strategy for patients with asymptomatic severe aortic stenosis until symptoms develop, early surgery for asymptomatic aortic stenosis remains controversial. This study aimed to compare the outcomes of early surgery versus conservative strategy for patients with asymptomatic severe aortic stenosis.MEDLINE and EMBASE were searched through February 2020 to identify clinical trials that investigated early surgery and conservative strategy for patients with asymptomatic severe aortic stenosis. From each study, we extracted the hazard ratio of all-cause mortality and cardiovascular mortality. Subgroup analyses were conducted by dividing into severe aortic stenosis (peak aortic jet velocity ≥4.0 m/s, mean aortic pressure gradient ≥40 mm Hg, or aortic valve area ≤1.0 cmOne randomized controlled trial and 7 observational studies were identified. Pooled analyses demonstrated that all-cause mortality and cardiovascular mortality for early surgery were significantly lower compared with conservative strategy (hazard ratio, 0.49; 95% confidence interval, 0.36-0.68; P .0001, hazard ratio, 0.42; 95% confidence interval, 0.22-0.82; P = .01, respectively). Subgroup analyses showed significant reduction for early surgery in all-cause mortality (severe aortic stenosis: hazard ratio, 0.52; 95% confidence interval, 0.35-0.78; P = .001, very severe aortic stenosis: hazard ratio, 0.38; 95% confidence interval, 0.17-0.85; P = .02).We demonstrated that early surgery was associated with significant reduction in all-cause and cardiovascular mortality in patients with severe aortic stenosis. Further randomized trials are warranted to confirm our findings.

Transcatheter aortic valves provide superior systolic hemodynamic performance in terms of valvular pressure gradient and effective orifice area compared with equivalent size surgical bioprostheses. However, in depth investigation of the flow field structures is of interest to examine the flow field characteristics and provide experimental evidence necessary for validation of computational models. The goal of this study was to compare flow field characteristics of the three most commonly used transcatheter and surgical valves using phase-locked particle image velocimetry (PIV). 26-mm Edwards SAPIEN 3, 26-mm Medtronic CoreValve, and 25-mm Carpentier-Edwards PERIMOUNT Magna were examined in a pulse duplicator with input parameters matching ISO-5840, that is, heart rate of 70 beats/min, cardiac output of 5 L/min, and mean aortic pressure of 100 mm Hg. A 2D PIV system was used to obtain flow velocity and viscous shear stress fields during the entire cardiac cycle. In vitro testing showed that the mean transvalvular pressure gradient was lowest for SAPIEN 3, followed by CoreValve, and PERIMOUNT Magna surgical bioprosthesis. In addition, the viscous shear stress magnitude within the jet boundary layer was higher in PERIMOUNT Magna than CoreValve and SAPIEN 3 at the peak of the flow. However, the measured shear stress values were below the known threshold for platelet activation and red blood damage. Therefore, shear-induced platelet activation is unlikely to take place during systole in the three bioprosthetic heart valves. The PIV measurements can be used for verification and validation of computational simulations.

Background: Global longitudinal strain (GLS) has incremental value in assessing left ventricular (LV) function in severe aortic stenosis and is related to clinical outcome after transcatheter aortic valve replacement (TAVR). We sought to identify relevant echocardiographic predictors of GLS improvement and myocardial function recovery after TAVR. Methods: We analyzed baseline and 12-month follow-up echocardiograms for LV strain analysis from 123 patients who underwent at Emory University Hospital with the Edwards SAPIEN valve between 7/2007 and 7/2013. Results: At baseline, 61 had reduced LV ejection fraction (LVEF) ≤50% (rEF), and 80 had preserved LVEF >50% (pEF). Higher baseline mean pressure gradient (MPG) and aortic peak velocity (AV Vmax) predicted myocardial function recovery defined as ≥20% improvement in global longitudinal strain (r = 0.29, p

Aim. Analysis of features of diurnal blood pressure profile (DBPP), arterial stiffness and left ventricular (LV) structure and function in patients with arterial hypertension (AH) and impaired glucose metabolism. Materials and methods. The study included 220 patients with AH: 30 - without impaired glucose metabolism, 160 with prediabetes, and 30 patients with type 2 diabetes mellitus (DM). Prediabetes were determined by the results of an oral glucose tolerance test. 24-hour blood pressure monitoring were conducted, the main parameters of arterial stiffness and central aortic pressure (CAP) were examined using the BPLab Vasotens complex of OOO "Petr Telegin" (Russia). Echocardiography using a tissue doppler was performed on a Siemens ACUSON X 300 ultrasound device (Korea). Results. It was established that in patients with AH and impaired glucose metabolism the main parameters of DBPP, arterial stiffness, CAP and LV structure and function were comparable. In patients with AH and prediabetes were recorded increased levels of systolic and pulsatile blood pressure in the brachial artery and aorta, high mean aortic pressure within 24 hours, the level of diastolic blood pressure in the brachial artery and aorta during the night, morning rise of systolic blood pressure speed, "pressure load" mainly at night, than in patients with isolated AH. The pathological type of the "non-dipper" curve was detected 2.5 times more often in patients with type 2 DM and prediabetes than in patients with AH without impaired glucose metabolism. In patients with AH and prediabetes the pulse wave velocity, the augmentation index in the brachial artery and aorta characterizing the stiffness of the vessel wall and LV structure and function was significantly higher than in patients without impaired glucose metabolism. Concentric LV hypertrophy was registered 3.3 times more often than in patients without impaired glucose metabolism, and LV diastolic dysfunction with violation of its relaxation was revealed in 100% of cases. Conclusion. In patients with AH and prediabetes, the pathological changes in the parameters of DBPP, arterial stiffness and LV structure and function were comparable with those with AH and type 2 DM, and were more pronounced than in patients without impaired glucose metabolism.

Purpose The Left Atrial Assist Device (LAAD) is a novel device in development for mechanical circulatory assistance in patients who have heart failure with preserved ejection fraction (HFpEF). The device is implantable in the mitral position and delivers blood from the left atrium to the left ventricle. We report our results of the first LAAD in vivo implantation to assess the operational performance. Methods The LAAD was implanted in calves (n=4; mean weight 78.9 kg) using cardiopulmonary bypass (CPB) support through a left atrial incision. Horizontal mattress sutures were placed circumferentially around the mitral annulus and through the LAAD sewing ring (diameter 29 mm, Fig. 1a). Various pump-operating conditions, including mean pump speeds ranging from 3,600 to 6,000 rpm, were evaluated after the CPB was weaned, and the hemodynamics for each pump setting were recorded. Results The LAAD responded to all control inputs and ran as expected during the experiment. The cardiac output and mean aortic pressure increased (from 5.3 to 6.0 L/min, and from 69 to 77 mm Hg, respectively) by increasing the pump speed from 3,600 to 4,400 rpm, while the mean left atrial pressure decreased (from 15.1 to 8.3 mm Hg). These parameters stayed the same at pump speeds of 4,400 to 5,200 rpm. The left ventricular end-diastolic pressure, central venous pressure and heart rate remained stable at speeds ranging from 3,600 to 5,200 rpm. Suction events were occasionally observed at speeds over 4,400 rpm, mainly because of the small size of the left atrium. The epicardial echocardiography showed good positioning of the LAADs, with no evidence of obstruction of the left ventricular outflow tracts (Fig. 1b). Conclusion The implantation of the LAADs in calves was successful, and the pump showed intended improvement of the hemodynamics in the normal calf hearts. Additional studies are underway to evaluate the pump performance under diastolic heart failure conditions.

BACKGROUND Transcatheter heart valve thrombosis (THV-t) and endocarditis (THV-e) are relevant complications after transcatheter aortic valve implantation (TAVI). Transcatheter heart valve (THV) dysfunction definition is mostly based on Doppler (stenosis/regurgitation) without considering leaflets characteristics. PURPOSE To evaluate the additional diagnostic value of leaflets echocardiographic features over Doppler when prosthetic valve complication is suspected. METHODS Among 621 post-TAVI patients, 128 cases with probable valve complication were identified. THV-t was finally diagnosed in 13 patients (10%) and THV-e in 8 (6%), while the remaining 107 (84%) had no definitive diagnosis of thrombosis/endocarditis (THV-no). We analyzed at 2 time points (baseline and follow-up) both traditional Doppler parameters and leaflets morpho-functional features. RESULTS Both Doppler and leaflets parameters showed high sensitivity (sensitivity 92%) and low specificity (ranging from specificity 32% to 74%) in detecting THV-t. Interestingly, the combination of mean aortic pressure gradient ≥20 mm Hg and leaflet thickening significantly improved the specificity of echocardiography for diagnosis of THV thrombosis (specificity 94%). On the other hand, echocardiographic diagnosis of THV endocarditis remained limited by very low sensitivity despite showing high specificity. CONCLUSIONS The combination of Doppler and leaflets parameters can improve the echocardiographic diagnosis of THV thrombosis in post-TAVI patients with suspicious symptoms, via a significant increase in the overall test specificity. This would potentially allow more rational gatekeeping to more expensive/invasive diagnostic examinations (eg, CT scan) or therapeutic trials (eg, unnecessary anticoagulation).

Aim: to evaluate the data of the central aortic pressure and arterial stiffness during the daily monitoring procedure in postmenopausal women with osteoporosis. Methods: 79 postmenopausal women (age from 57 to 78) were examined. All patients were divided into two groups: the first group consisted of 36 women with osteoporosis, the second group consisted of 43 women – control group. A daily monitoring of central aortic pressure and arterial stiffness were performed all women by the apparatus BPLab v.3.2. Results: increase of the mean daily of systolic, diastolic and mean aortic pressure was found out in women with osteoporosis. The main data of arterial stiffness (PWV, ASI, AASI, PPA) were higher in this group of women. The direct correlation between the data of central aortic blood pressure, arterial stiffness and presence of osteoporotic fractures and their number, as well as indicators of absolute ten-year risk of osteoporotic fractures and hip fracture was revealed. Pathological profiles of systolic pressure in aortae were more frequent in patients with osteoporosis. The type of hyperdispers was predominant. Conclusions: the results obtained may indicate a possible relationship between cardiovascular diseases and osteoporosis.

The technology of 3D-printing has allowed the production of entirely soft pumps with complex chamber geometries. We used this technique to develop a completely soft pneumatically driven total artificial heart from silicone elastomers and evaluated its performance on a hybrid mock circulation. The goal of this study is to present an innovative concept of a soft total artificial heart (sTAH). Using the form of a human heart, we designed a sTAH, which consists of only two ventricles and produced it using a 3D-printing, lost-wax casting technique. The diastolic properties of the sTAH were defined and the performance of the sTAH was evaluated on a hybrid mock circulation under various physiological conditions. The sTAH achieved a blood flow of 2.2 L/min against a systemic vascular resistance of 1.11 mm Hg s/mL (afterload), when operated at 80 bpm. At the same time, the mean pulmonary venous pressure (preload) was fixed at 10 mm Hg. Furthermore, an aortic pulse pressure of 35 mm Hg was measured, with a mean aortic pressure of 48 mm Hg. The sTAH generated physiologically shaped signals of blood flow and pressures by mimicking the movement of a real heart. The preliminary results of this study show a promising potential of the soft pumps in heart replacements. Further work, focused on increasing blood flow and in turn aortic pressure is required.

In this study, we developed a trans-valve left ventricular assist device (LVAD) that unites a rear-impeller axial-flow blood pump (AFBP) and a polymer membrane valve placed at the aortic valve position. The diameter and length of the rear impeller AFBP was 12 and 63 mm, respectively. The polymer membrane valve was similar to the jelly-fish valve consisting of a valve leaflet made of silicone rubber (thickness 0.5 mm), valve ring (diameter: 25 mm), and valve spokes. The trans-valve LVAD was examined in a mock circulation. An implantable pulsatile flow (PF) VAD was connected to an atrial reservoir to simulate the left ventricle (LV), and the Hall valve was worn in the inflow port, and the trans-valve LVAD was placed in the outflow port as an outflow valve. When the motor rotational speed increased to 26 400 rpm, the mean aortic flow increased from 4.2 to 5.3 L/min, mean aortic pressure increased from 83.4 to 100 mm Hg, and mean motor current of the implantable PF VAD decreased from 1.18 to 0.94 A (unloading effect on LV -21%). The energy equivalent pressure increased from 85.2 to 102 mm Hg, and surplus hemodynamic energy (SHE) decreased by -15.4% from the baseline. In conclusion, the trans-valve LVAD has an advantage of preserving pulsatility without any complicated mechanism and is a novel and promising LV support device.

Mean aortic pressure (MAP) is a major determinant of perfusion in all organs systems. The ability to forecast MAP would enhance the ability of physicians to estimate prognosis of the patient and assist in early detection of hemodynamic instability. However, forecasting MAP is challenging because the blood pressure (BP) time series is noisy and can be highly non-stationary. The aim of this study was to forecast the mean aortic pressure five minutes in advance, using the 25 Hz time series data of previous five minutes as input. We provide a benchmark study of different deep learning models for BP forecasting. We investigate a left ventricular dwelling transvalvular micro-axial device, the Impella, in patients undergoing high-risk percutaneous intervention. The Impella provides hemodynamic support, thus aiding in native heart function recovery. It is also equipped with pressure sensors to capture high frequency MAP measurements at origin, instead of peripherally. Our dataset and the clinical application is novel in the BP forecasting field. We performed a comprehensive study on time series with increasing, decreasing, and stationary trends. The experiments show that recurrent neural networks with Legendre Memory Unit achieve the best performance with an overall forecasting error of 1.8 mmHg.

The clinical management of patients with low gradient severe aortic stenosis (LG-SAS) and preserved left ventricular ejection fraction (LVEF) remains challenging owing to their heterogeneity. The aim to this study was to evaluate the relation between an ejection dynamic parameter linked to AS severity and outcome, the ratio of acceleration time (AT) to ejection time (ET), in a cohort of patients with LG-SAS and preserved LVEF. Three hundred and fifty-six patients with LG-AS (defined by AVA ≤1 cm² and/or AVAi ≤0.6 cm²/m² and mean aortic pressure gradient40 mm Hg) and preserved LVEF ≥50% were studied. The relation between AT/ET and all-cause and cardiac mortality during follow-up was studied. Median follow-up was 41 months (interquartile range, 35 to 47 months). Median AT/ET was 0.32 (interquartile range, 0.29 to 0.36). The 5-year estimates of all-cause and cardiac mortality were respectively 57 ± 7%, 36 ± 7% for patients with AT/ET0.36 versus 43 ± 4%, 16 ± 3% for patients with AT/ET ≤0.36 (p = 0.024 and p0.001, respectively). After adjustment on known predictors of outcome including aortic valve replacement used as a time-dependent covariate, there was a significant increase in all-cause mortality risk for patients with AT/ET0.36 (adjusted hazard ratio 2.04 [95% confidence interval, 1.32 to 3.13]; p = 0.001) and cardiac mortality risk (adjusted hazard ratio 2.89 [95% confidence interval, 1.54 to 5.43]; p0.001) compared with patients with AT/ET ≤0.36. The association of AT/ET0.36 and all-cause or cardiac mortality risk was consistent in subgroups of patients with LG-SAS and preserved EF. In conclusion, an AT/ET ratio of more than 0.36 is an independent predictor of mortality in patients with LG-SAS and preserved EF.

This study was to evaluate the prognostic significance of low gradient severe aortic stenosis (LG SAS) and preserved left ventricular ejection fraction (LVEF) with the integration of echocardiographic and clinical data.The study included 172 patients with LG SAS (AVAi ≤ 0.6 cmLF/LG SAS had significantly smaller AVAi, lower SVi, a higher prevalence of atrial fibrillation (28% vs 12% P = .01) and diabetes (47% vs 27% P = .007) and lower 3-year cumulative survival than NF/LG SAS. Multivariable analysis showed that dyspnea, renal dysfunction (CI 1.42-3.99, P .01), left atrial diameter, and SVi were independently associated with an increased risk for all-cause mortality. Aortic valve intervention (AVI) improved survival in LF/LG SAS (68% vs 48%, P .05) in comparison with medical management (HR: 4.20, CI: 1.12-15.76, P = .03), but only modestly in NF/LG SAS (75% vs 65% P .05).Outcome of LG SAS was independently associated with clinical characteristics. AVI likely improved outcome of LF/LG SAS who had high-risk clinical characteristics and unfavorable echocardiographic findings.

Background Quantitative flow ratio ( QFR ), a novel functional angiography technique, computes fractional flow reserve ( FFR ) without pressure wires or adenosine. We investigated interindividual variations in the adenosine‐induced hemodynamics during FFR assessment and their influence on QFR diagnostic performance. Methods and Results Patients with coronary stenoses who underwent intracoronary pressure and flow assessment were analyzed. Adenosine‐induced hemodynamics during FFR measurement were determined by the percentage change in mean aortic pressure (%ΔPa) and the resistive reserve ratio ( RRR ). The diagnostic performance of QFR was evaluated and compared in each tertile of %ΔPa and RRR using FFR as reference. A total of 294 vessels (245 patients) were analyzed. Mean FFR was 0.80±0.11. Individuals showed a wide variation in the adenosine response in terms of %ΔPa (ranging from −75% to 43%; median, −9% [interquartile range, −3% to −17%]) and the RRR (ranging from 0.45 to 20.15; median, 3.1 [interquartile range, 2.1–4.9]). No significant differences for diagnostic efficiency of QFR were found between tertiles of %ΔPa (area under the curve for the receiver‐operating characteristic analysis, 0.950 in tertile 1, 0.929 in tertile 2, and 0.910 in tertile 3; P =0.270) or between tertiles of the RRR (area under the curve for the receiver‐operating characteristic analysis, 0.909 in tertile 1, 0.923 in tertile 2, and 0.959 in tertile 3; P =0.167). The classification agreement between QFR and FFR was not significantly modified by %ΔPa (tertile 1, 89%; tertile 2, 87%; and tertile 3, 86%; P =0.827) or by the RRR (tertile 1, 86%; tertile 2, 85%; and tertile 3, 91%; P =0.398). Conclusions Patients undergoing FFR assessment show large interindividual variations in the magnitude of adenosine‐induced hemodynamics. However, such variations do not affect the diagnostic performance of QFR in assessing the functional relevance of observed stenoses.

Objective: Continuous Flow Left Ventricular Assist Devices (CFLVAD) are circulatory support devices that are implanted in patients with end-stage heart failure. We developed a novel control algorithm for CFLVAD to maintain physiologic perfusion while avoiding ventricular suction using only the intrinsic pump measurement of pump speed and without utilizing model-based estimation. Methods: The controller objective is to maintain a differential pump speed setpoint. A mathematical model of the circulatory system coupled with a model of a CFLVAD was used to test the control algorithm in silico . Robustness and efficacy were evaluated by comparing the proposed control algorithm to constant speed control, differential pump pressure control, mean aortic pressure control, and ventricular end diastolic pressure control during (1) rest and exercise conditions, (2) a rapid eight-fold increase in pulmonary vascular resistance under rest and exercise, (3) transitions from rest to exercise, and exercise to rest, (4) safe mode during left ventricular asystole, and (5) RPM measurement noise of 1% to 10% for (1) to (4). Results and conclusion: The control algorithm provided adequate perfusion while preventing ventricular suction for all test conditions. Performance did not deteriorate significantly with pump speed measurement noise of up to 6%. The safe mode successfully detected asystole and maintained adequate perfusion to sustain life even when the differential pump speed was low. Significance: Maintaining a constant differential pump speed can simultaneously achieve physiologic perfusion and suction prevention without needing unreliable, direct measurements of flow or pressure, or complex parameter or model-based estimation techniques.

BACKGROUND: Impairment of coronary flow is usually evaluated by considering the ratio of two measurements. Fractional flow reserve (FFR) estimates impact on an epicardial artery by taking mean post-stenotic pressure divided by mean aortic pressure, both obtained during adenosine induced hyperemia. Coronary flow reserve (CFR) compares hyperemic flow or velocity with the baseline situation, also as a ratio. As severity of underlying pathology may differ for men and women, we investigate the impact of these differences on relevant metrics.METHODS: As sex associated differences may cancel out in a ratio, this weakness of a ratio can be compensated by analyzing the intrinsic companion (C) and consider polar coordinates. Thus, besides the familiar ratio based metrics, we also analyze FFRC and CFRC. Outcomes of in silico studies are employed to extrapolate actual patient data and predict consequences. For FFR 129 patients (38 women) were invasively studied using pressure wires. CFR was measured noninvasively for the left anterior descending coronary artery by recording ultrasound based Doppler velocity in 114 individuals (28 women).RESULTS: The FFR can be identified as an indicator of the pressure gradient over the stenosis (R=-0.90), while FFRC differs for men compared to women (P=0.04) and correlates (R=0.93) with post-stenotic driving pressure. CFR shows a difference for men versus women (P=0.04) and is best associated with hyperemic flow (R=0.64), whereas CFRC relates to hyperemia recruited velocity (R=0.97). Simulation studies show that FFR may differ for both sexes when considering elderly.CONCLUSIONS: Analysis of ratios require inclusion of the companion, and sex-specific differences deserve attention.

The aim of this study was to explore the relationship between the tricuspid annular plane systolic excursion/pulmonary arterial systolic pressure (TAPSE/PASP) ratio and model for end-stage liver disease (MELD) score in patients with advanced heart failure.A total of 103 patients with advanced heart failure evaluated for candidacy for heart transplantation were included in this study. TAPSE was measured by M‑mode echocardiography and cardiac catheterization was performed. TAPSE/ PASP ratio and MELD score were calculated.The median age of patients was 49 (40.5-54) years and the majority were male (92%). The percentage of patients with ischemic cardiomyopathy was 40%. The mean value of the group's MELD score was 10 ± 3.3 and the median value of TAPSE/PASP 0.24 (0.18-0.34). There was a moderate negative correlation between TAPSE/PASP and MELD score (r: -0.38, p 0.001). Right atrial pressure (RAP) and left ventricular end-diastolic pressure (LVEDP) were also negatively correlated with TAPSE/PASP (correlation coefficients were r: -0.562 and r: -0.575, respectively). In patients with a lower TAPSE/PASP ratio, MELD score, LVEDP and RAP were higher and tricuspid regurgitation was more severe, but there were no significant differences between cardiac output (CO) and mean aortic pressure (mean BP). The presence of ischemia was found to be an independent predictor for lower values of TAPSE/PASP.The lower TAPSE/PASP obtained on echocardiography may be a sign of the multi-organ failure defined as a high MELD score in patients with advanced heart failure.EINLEITUNG: Ziel dieser Studie war es, die Beziehung zwischen dem TAPSE/PASP-Verhältnis („tricuspid annular plane systolic excursion“/systolischer Pulmonalarteriendruck) und dem Model-for-end-stage-liver-disease(MELD)-Score bei Patienten mit fortgeschrittener Herzinsuffizienz zu untersuchen.Die Studie schloss insgesamt 103 Patienten mit fortgeschrittener Herzinsuffizienz ein, deren Anwartschaft auf eine Herztransplantation geprüft wurde. Die TAPSE wurde mithilfe der M‑Modus-Echokardiographie gemessen, und es erfolgte eine Herzkatheterisierung. Das TAPSE/PASP-Verhältnis und der MELD-Score wurden berechnet.Die Patienten hatten ein medianes Alter von 49 (40,5–54) Jahren und waren mehrheitlich männlich (92 %). Der Anteil der Patienten mit ischämischer Kardiomyopathie betrug 40 %. Der Mittelwert des MELD-Scores lag in der Gruppe bei 10 ± 3,3 und der Mittelwert des TAPSE/PASP-Verhältnisses bei 0,24 (0,18–0,34). Es fand sich eine mäßige negative Korrelation zwischen TAPSE/PASP und MELD-Score (r: −0,38, p 0,001). Der rechtsatriale (RA) Druck und der linksventrikuläre enddiastolische Druck (LVEDP) korrelierten ebenfalls negativ mit TAPSE/PASP (Korrelationskoeffizienten r: −0,562 bzw. r: −0,575). Bei Patienten mit einem niedrigeren TAPSE/PASP-Verhältnis waren MELD-Score, LVEDP und RA-Druck höher und die Trikuspidalklappeninsuffizienz schwerwiegender, es bestanden aber keine signifikanten Unterschiede in Bezug auf Herzzeitvolumen und mittleren Aortendruck (mittlerer Blutdruck). Eine bestehende Ischämie zeigte sich als unabhängiger Prädiktor für niedrige TAPSE/PASP-Werte.Das erniedrigte TAPSE/PASP-Verhältnis, wie es in der Echokardiographie ermittelt wurde, könnte ein Zeichen des Multiorganversagens, definiert als hoher MELD-Score, bei Patienten mit fortgeschrittener Herzinsuffizienz sein.

The aim of the work was to evaluate the hydrodynamic characteristics of the heart valve bioprosthesis «UniLine», intended for prosthetics of the aortic valve. Materials and methods . In the contest three prostheses «UniLine» with a size of 21, 23, 25 mm, intended for clinical use. The evaluation of the hydrodynamic parameters was carried out in a Vivitro pulsating flow setup (Vivitro Labs, Canada) simulating the operation of the «left» half of the heart. Estimated hydrodynamic function of all prostheses when creating the physiological mode of operation of the unit - impact volume = 70 ml, minute volume = 5 l/min, mean aortic pressure = 100 mmHg. Results . The average trans-prosthetic gradient was 5,4-15,5 mmHg.; the maximum trans-prosthetic gradient was 11,9-25,2 mmHg; effective orifice area 1,38-2,15 cm2; regurgitation fraction 1,5-3,905%; productivity index, calculated from the inner orifice diameter 47,4-68,5%. Conclusion . Bioprostheses «UniLine», intended for aortic position, demonstrated satisfactory hydrodynamic in vitro characteristics, comparable with existing world analogues. The existing design has the potential to increase hydrodynamic efficiency, but requires advanced approaches and methods, such as FSI, for its implementation.

Objectives The aim of this study was to explore the effect of one stenosis in a daughter artery on the fractional flow reserve (FFR) of another stenosis parallels in side branch. Background: The impact of one stenosis on the FFR of another parallel stenosis has not been evaluated. Methods: The proximal segments of the left anterior descending (LAD) and left circumflex (LCX) arteries were exposed and encircled with a Teflon pledget complex in seven swine (55–70 kg). Five degrees of stenosis (to approximate angiographic diameter stenoses of 0%, 25%, 50%, 75%, and 100%) were made by tightening the pledgets. FFR was evaluated simultaneously in the LAD and the LCX with two pressure wires in each coronary artery. A mixed-effects linear model was used to evaluate the association between the FFR values. Results: A total of 115 paired FFR values were obtained. The FFR of the LAD and LCX were not significantly associated with each other (F = 0.237 and P = 0.627 for the LCX FFR to predict the LAD FFR; F = 0.541 and P = 0.463 for the LAD FFR to predict the LCX FFR). Conclusions: The individual FFR values of each parallel stenosis in the LAD and the LCX were not significantly influenced by each other. This relationship was independent of the mean aortic pressure and heart rate. © 2016 Wiley Periodicals, Inc.

Objectives This study sought to assess the impact of a wide range of mean right atrial pressure (P ra ) on fractional flow reserve (FFR) measurements. Background FFR invasively assesses the ischemic potential of coronary stenoses. FFR is calculated as the ratio of mean distal coronary pressure (P d ) to mean aortic pressure (P a ) during maximal hyperemia. The P ra is considered to have little impact if it is within normal range, so it is neglected in the formula. Methods In 1,676 stenoses of 1,235 patients undergoing left-right heart catheterization for ischemic (642 [52%]) or valvular heart disease (593 [48%]), the authors compared the FFR values calculated without accounting for P ra (FFR= P d /P a ) to the corresponding myocardial fractional flow reserve (FFR myo ) values accounting for P ra (FFR myo = P d − P ra /P a − P ra ). Results The median P ra was 7 (interquartile range [IQR]: 5 to 10) mm Hg with a maximum of 27 mm Hg. The correlation and agreement between FFR and FFR myo was excellent (R 2 = 0.987; slope 1.096 ± 0.003). The median FFR (0.85; IQR: 0.78 to 0.91) was slightly but statistically significantly higher than the median FFR myo (0.83; IQR: 0.76 to 0.90; p myo ≤0.80 in 110 (9%) stenoses. No FFR value above 0.80 provided an FFR myo ≤0.75. Conclusions The difference between FFR and FFR myo was minimal even in patients with markedly increased P ra . FFR values above the gray zone (i.e., >0.80) did not yield values below the gray zone (i.e., ≤0.75) in any case, which suggests that the impact of right atrial pressure on FFR measurement is indeed negligible.

Background Risk assessment of patients with low-gradient severe aortic stenosis (LG-SAS) despite preserved left ventricular ejection fraction (LVEF) remains challenging. Purpose To evaluate the relationship between the Dimensionless Index (DI) – the ratio of the left ventricular outflow tract (LVOT) time-velocity integral to that of the aortic valve jet – and mortality in patients with LG-SAS and preserved LVEF. Methods In total, 755 patients with LG-SAS (defined by AVA ≤ 1 cm2 and/or AVAi ≤ 0.6 cm2/m2 and mean aortic pressure gradient 35 mL/m2 (normal flow [NF]). Results After adjustment for age, gender, body mass index, Charlson Comorbidity Index, history of hypertension, documented coronary artery disease, history of atrial fibrillation, AS-related symptoms, LVEF, indexed LV ventricular mass, aortic valve area (AVA), and aortic valve replacement (AVR) as a time dependent covariate, patients with LG-LF and DI Fig. 1 ). Conclusion Among patients with LG severe AS and preserved LVEF, decreased DI

Objective Rotary blood pumps (RBP) are long-term mechanical circulatory support devices that support a failing heart by pumping blood. Ventricular collapse and suction, which can lead to myocardial damage and arrhythmias, is a significant risk factor during RBP support. The RBP also needs to maintain pump flow to match perfusion demand over a wide range of physiologic conditions. We have developed a novel sensorless control algorithm to maintain physiologic perfusion while avoiding ventricular suction, using a suction index (SI) extracted from the intrinsic pump speed measurements. Methods The objective of the proposed control algorithm is to maintain an SI setpoint. Using nonlinear mathematical models of a human circulatory system and a RBP, efficacy and robustness of the proposed algorithm with 2% RPM measurement were tested in-silico by comparing it to differential pump speed control, differential pump pressure control, constant speed control, and mean aortic pressure control during (1) rest and exercise conditions, (2) a rapid eight-fold increase in pulmonary vascular resistance for rest and exercise, and (3) transition from exercise to rest. Results The proposed control algorithm provided physiologic perfusion while simultaneously preventing ventricular suction for all test conditions. The performance of the proposed control algorithm was superior to other tested control strategies in avoiding suction. Conclusion Maintaining a reference SI effectively provided physiologic perfusion and prevented ventricular suction. Significance The proposed SI control approach can meet physiologic circulatory demand and avoid suction in RBP without requiring the use of unreliable pressure or flow sensors or a pump model.

Objectives. To examine the influence of hydrostatic pressure on fractional flow reserve (FFR) in vivo.Background. Systematic differences in FFR values have been observed previously in the left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA). It has been suggested that as the hydrostatic pressure variations caused by the height differences between the catheter tip (mean aortic pressure (Pa)) and pressure-wire sensor (mean distal intracoronary pressure (Pd)) are small, intracoronary pressure need not be corrected.Methods. Resting Pd/Pa and FFR values in 23 patients (27 lesions) were measured and compared in supine and prone positions. These values were corrected by hydrostatic pressure influenced by height levels and compared. Height differences between Pa and Pd were calculated using coronary computed tomography angiographies.Results. In LAD, resting Pd/Pa and FFR values were significantly higher in the prone position than in the supine position (0.97 ± 0.05 vs 0.89 ± 0.04,P<0.001(resting Pd/Pa); 0.81 ± 0.09 vs 0.72 ± 0.07,P<0.001(FFR)). Conversely, in LCX and RCA, these values were significantly lower in the prone position (LCX: 0.93 ± 0.03 vs 0.98 ± 0.03,P<0.001(resting Pd/Pa); 0.84 ± 0.05 vs 0.89 ± 0.04,P<0.001(FFR); RCA: 0.91 ± 0.04 vs 0.98 ± 0.03,P=0.005(resting Pd/Pa); 0.78 ± 0.07 vs 0.84 ± 0.07,P=0.019(FFR)). FFR values corrected by hydrostatic pressure showed good correlations in the supine and prone positions (R2 = 0.948 in LAD;R2 = 0.942 in LCX;R2 = 0.928 in RCA).Conclusions. Hydrostatic pressure variations due to height levels influence intracoronary pressure measurements and largely affect resting Pd/Pa and FFR, which might have caused systematic differences in FFR values between the anterior and posterior coronary territories.

Background: The differential effects of rapid cardiac pacing on small and large vessels have not been well-established. The objective of this study was to investigate the effect of pacing-induced acute tachycardia on hemodynamics and arterial stiffness. Methods: The pressure and flow waves in ascending aorta and femoral artery of six domestic swine were recorded simultaneously at baseline and heart rates (HR) of 135 and 155 beats per minutes (bpm) and analyzed by the models of Windkessel and Womersley types. Accordingly, the flow waves were simultaneously measured at carotid and femoral arteries to quantify aortic pulse wave velocity (PWV). The arterial distensibility was identified in small branches of coronary, carotid and femoral arteries with diameters of 300–600 μm by ex vivo experiments. Results: The rapid pacing in HR up to 135 bpm reduced the total arterial compliance, stroke volume, systemic pulse pressure, and central systolic pressure by 36 ± 17, 38 ± 26, 29 ± 16, and 23 ± 12%, respectively, despite no statistical difference of mean aortic pressure, cardiac output, peripheral resistance, and vascular flow patterns. The pacing also resulted in a decrease of distensibility of small muscular arteries, but an increase of aortic distensibility. Pacing from 135 to 155 bpm had negligible effects on systemic and local hemodynamics and arterial stiffness. Conclusions: There is an acute mismatch in the response of aorta and small arteries to pacing from basal HR to 135 bpm, which may have important pathological implications under chronic tachycardia conditions.

Background We investigated whether and to what extent stenosis of predominant collateral donor artery (PCDA) affects coronary collateral flow in relation to blood pressure (BP) in type 2 diabetic patients with chronic total occlusion (CTO). Methods Collateral flow index (CFI) as derived from intracoronary pressure distal to occluded segment and mean aortic pressure in 220 type 2 diabetic patients and 220 propensity score matched non-diabetic controls undergoing percutaneous coronary intervention for CTO. The severity of PCDA stenosis was graded according to lumen diameter narrowing. Results CFI decreased stepwise from mild to severe stenosis of the PCDA and was lower in diabetic patients with moderate or severe PCDA stenosis than in non-diabetic controls (0.36 ± 0.10 vs. 0.45 ± 0.08, P

AIMS In this study we aimed to test the hypothesis that left ventricular (LV) afterload reduction in severe aortic valve stenosis (AS) by transcatheter aortic valve implantation (TAVI) acutely improves coronary haemodynamics. METHODS AND RESULTS This was a prospective, pathophysiologic study in 40 patients with severe AS undergoing TAVI. Endpoints were determined invasively immediately before and after TAVI without altering coronary stenotic lesions if present. Myocardial hyperaemia was induced by intravenous adenosine. The primary study endpoints were coronary flow reserve (thermodilution-derived CFR), and fractional flow reserve (FFR). The secondary study endpoint was coronary collateral flow index (CFI) as obtained during a one-minute coronary balloon occlusion. CFR was 1.9±0.9 before TAVI and 2.0±1.0 after TAVI (p=0.72). FFR was 0.90±0.08 before TAVI and 0.93±0.08 after TAVI (p=0.0021). The TAVI-induced increase in FFR was related to a significant decrease in hyperaemic mean aortic pressure from 71±16 mmHg before TAVI to 67±15 mmHg after TAVI (p=0.0099). Hyperaemic CFI increased from 0.127±0.083 before to 0.146±0.090 after TAVI (p=0.0508). CONCLUSIONS CFR appears not to be acutely affected by LV afterload reduction among patients with severe AS in response to TAVI. However, it acutely improves FFR; this occurs via lowering of mean aortic pressure. Hyperaemic coronary collateral flow index tends to augment in response to TAVI.

The intraindividual variability and association of human collateral functional supply to different arterial regions is unknown. The primary study end point was collateral flow index (CFI) as obtained in the coronary artery (CA), renal artery (RA), left superficial femoral artery (SFA), and left subclavian artery (SCA) of the same individual. CFI is the ratio between simultaneously recorded mean arterial occlusive pressure divided by mean aortic pressure both subtracted by mean central venous pressure. In 100 patients admitted for diagnostic coronary angiography, CFI was assessed in 3 arterial regions (CA, RA, and SFA), 13 patients underwent CFI measurements in all 4 territories. By quantitative coronary angiography, 82 patients had a stenosis

Hemorrhage is a frequent event in hospital and prehospital settings. The aim of the present study was to investigate whether centhaquin improves 24-h survival and reduces the total volume of required fluids in an established model of swine hemorrhagic shock.Twenty-five pigs were instrumented and subjected to hemorrhagic shock. The animals were randomly allocated in two experimental groups, the control (vehicle) (n = 10) and the centhaquin groups (0.015 mg/kg, n = 10); all animals received lactated Ringer solution in the resuscitation phase until their mean arterial pressure reached 90% of the baseline. A sham group (n = 5) was added a posteriori to mimic the hemodynamic profile of the centhaquin group.A statistically significant difference was observed in the time required for the three groups to reach their target mean aortic pressure, 36.88 ± 3.26 min for the control group versus 9.40 ± 1.01 min for the sham group and 7.10 ± 0.97 min for the centhaquin group (P 0.001). The total amount of fluids in the control and the sham groups was significantly higher when compared with that of the centhaquin-treated animals (P 0.001). All 10 animals in the centhaquin group survived for 24 h, whereas only three animals survived in the control group and one animal in the sham group (P = 0.002).Centhaquin 0.015 mg/kg administered in the fluid resuscitation phase resulted in lower volume of fluids and better survival compared with control and sham-operated animals.

Active disturbance rejection control (ADRC) has gained popularity because it requires little knowledge about the system to be controlled, has the inherent disturbance rejection ability, and is easy to tune and implement in practical systems. In this paper, the authors compared the performance of an ADRC and an adaptive controller for an artificial blood pump for end-stage congestive heart failure patients using only the feedback signal of pump differential pressure. The purpose of the control system was to provide sufficient perfusion when the patients' circulation system goes through different pathological and activity variations. Because the mean arterial pressure is equal to the total peripheral flow times the total peripheral resistance, this goal was converted to an expression of making the mean aortic pressure track a reference signal. The simulation results demonstrated that the performance of the ADRC is comparable to that of the adaptive controller with the saving of modeling and computational effort and fewer design parameters: total peripheral flow and mean aortic pressure with ADRC fall within the normal physiological ranges in activity variation (rest to exercise) and in pathological variation (left ventricular strength variation), similar to those values of adaptive controller. An Active Disturbance Rejection Controller was developed for a rotary blood pump.The performance of ADRC was studied in activity and pathology variation.ADRC was easy to design and tune.ADRC demonstrated robust performance with excellent disturbance rejection.

We have advocated an axial flow blood pump called "valvo pump" that is implanted at the aortic valve position, and we have developed axial flow blood pumps to realize the concept of the valvo pump. The latest model of the axial flow blood pump mainly consists of a stator, a directly driven impeller, and a hydrodynamic bearing. The axial flow blood pump has a diameter of 33 mm and length of 74 mm, and the length of anatomical occupation is 33 mm. The axial flow blood pump is anastomosed to the aorta with polytetrafluoroethylene (PTFE) cuffs worn on the inflow and outflow ports. Dp-Q curves of the axial flow blood pump are flatter than those of ordinary axial flow pumps, and pump outflow of 5 L/min was obtained against a pressure difference of 50 mm Hg at a rotational speed of 9000 rpm in vitro. The axial flow blood pump was installed in a goat by anastomosing with the thoracic descending aorta using PTFE cuffs, and it was rotated at a rotational speed of 8000 rpm. Unlike in case of the ventricular assistance in parallel with the natural heart, pulsatilities of aortic pressure and aortic flow were preserved even when the pump was on, and mean aortic flow was increased by 1.5 L/min with increase in mean aortic pressure of 30 mm Hg. In conclusion, circulatory assistance in series with the natural heart using the axial flow blood pump was able to improve hemodynamic pulsatility, and it would contribute to improvement of end-organ circulation. .