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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

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.

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.

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.

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.

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.

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.

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 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

Background and Objectives Microvascular function is a useful predictor of left ventricular functional changes in patients with ST-segment elevation myocardial infarction (STEMI). We evaluated the usefulness of the hyperemic microvascular resistance index (hMVRI) for predicting long-term major adverse cardiovascular events (MACEs) in patients with STEMI assessed immediately after primary percutaneous coronary intervention (PCI). Subjects and Methods hMVRI were evaluated in 145 patients with first acute STEMI treated with primary PCI using an intracoronary Doppler wire. hMVRI was defined as the ratio of mean aortic pressure over hyperemic averaged peak velocity of infarct-related artery. Major adverse cardiovascular events (MACEs) included cardiac death and re-hospitalization for congestive heart failure. Results During the mean follow-up of 85±43 months, MACEs occurred in 17.2% of patients. Using a receiver-operating characteristics analysis, hMVRI >2.82 mm Hg·cm-1·sec (sensitivity: 87%; specificity: 69%; and area under curve: 0.818) was the best cut-off values for predicting future cardiac events. The Cox proportional hazard analysis showed that hMVRI was an independent predictor for long-term MACEs (hazard ratio 1.741, 95% confidence interval 1.348-2.264, p2.82 mm Hg·cm-1·sec (p

We investigated the influence of pneumoperitoneum#(PP) and postural change under inhalation anesthesia with isoflurane, which is routinely used in dogs, on the cardiovascular and respiratory systems. As test animals, 6 adult beagles were used. To induce anesthesia, atropine, butorphanol and propofol were intravenously injected. Anesthesia was maintained with 1.3 MAC (1.7%) isoflurane. The following were the experiment conditions: I:E ratio, 1:1.9; tidal air exchange, 20 ml/kg; and ventilation frequency, 14 times/min. Respiration was regulated so that the PaCO2 was approximately 35 to 40 mmHg before the start of the experiment. PP with CO2 (intraperitoneal pressure 15 mmHg) and a postural change (15°C) was performed during the experiment. As parameters of circulatory kinetics, heart rate (HR), mean aortic pressure (MAP), mean pulmonary arterial pressure (MPAP), central venous pressure (CVP), femoral venous pressure (FVP) and cardiac output (CO) were measured. As parameters of respiratory kinetics, airway pressure (PAW) and blood gas (BG) were measured. There were significant increases in HR, MAP, MPAP, CVP, FVP, CO, PAW and PaCO2 after PP in the horizontal position. There were significant increases in CVP, FVP, PAW and PaCO2 after PP in the Trendelenburg position. There were significant increases in the MPAP, CVP, FVP, PAW and PaCO2 after PP in the inverse Trendelenburg position. There was a significant difference in FVP after PP between the Trendelenburg position and inverse Trendelenburg position. The results of this experiment suggest that appropriate anesthesia control, such as changing the ventilation conditions after PP, is required for laparoscopic surgery under inhalation anesthesia with isoflurane.

A 69-year-old female with a history of hypertension and coronary artery disease presented with progressive exertional dyspnoea. Echocardiography revealed severe aortic stenosis with a mean aortic pressure gradient of 61 mmHg and an aortic valve area of 0.6 cm2. Surgical aortic valve replacement was aborted due to an unexpected porcelain aorta identified during exploratory pericardiotomy and transcatheter aortic valve replacement (TAVR) was considered. Extensive horseshoe calcifications and small diameters (from 4.2 to 5.6 mm) of the bilateral iliofemoral arteries and small left subclavian artery diameter (5.3 mm) precluded the transfemoral and trans-subclavian access. A direct aortic approach was prohibited due to the porcelain aorta. The right and left carotid arteries measured 6.6 and 6.8 mm, respectively, smaller than the 7.5 mm recommended for transcarotid access. Thus, …

Background Quantitative assessment of post-transcatheter aortic valve replacement (TAVR) aortic regurgitation (AR) remains challenging. We developed patient-specific anatomical models with pulsatile flow circuit and investigated factors associated with AR after TAVR. Methods Based on pre-procedural computed tomography (CT) data of the six patients who underwent transfemoral TAVR using a 23-mm SAPIEN XT, anatomically and mechanically equivalent aortic valve models were developed. Forward flow and heart rate of each patient in two days after TAVR were duplicated under mean aortic pressure of 80 mm Hg. Paravalvular leakage (PVL) volume in basal and additional conditions was measured for each model using an electromagnetic flow sensor. Incompletely apposed tract between the transcatheter and aortic valves was examined using a micro-CT. Results PVL volume in each patient-specific model was consistent with each patient's PVL grade, and was affected by hemodynamic conditions. PVL and total regurgitation volume increased with the mean aortic pressure, whereas closing volume did not change. In contrast, closing volume increased proportionately with heart rate, but PVL did not change. The minimal cross-sectional gap had a positive correlation with the PVL volumes (r = 0.89, P = 0.02). The gap areas typically occurred in the vicinity of the bulky calcified nodules under the native commissure. Conclusions PVL volume, which could be affected by hemodynamic conditions, was significantly associated with the minimal cross-sectional gap area between the aortic annulus and the stent frame. These data may improve our understanding of the mechanism of the occurrence of post-TAVR PVL.

The late gestation fetal ECG (fECG) has traditionally been difficult to characterize due to the low fECG signal relative to high maternal noise. Although new technologies have improved the feasibility of its acquisition and separation, little is known about its development in late gestation, a period in which the fetal heart undergoes extensive maturational changes. Here, we describe a method for the chronic implantation of radiotelemetry devices into late gestation ovine fetuses to characterize parameters of the fECG following surgery, throughout late gestation, and in the perinatal period. We found no significant changes in mean aortic pressure (MAP), heart rate (HR), or ECG in the 5 days following implantation; however, HR decreased in the first 24 h following the end of surgery, with associated increases in RR, PR, and QRS intervals. Over the last 14 days of fetal life, fetal MAP significantly increased, and HR significantly decreased, as expected. MAP and HR increased as labor progressed. Although there were no significant changes over time in the ECG during late gestation, the duration of the PR interval initially decreased and then increased as birth approached. These results indicate that although critical maturational changes occur in the late gestation fetal myocardium, the mechanisms that control the cardiac conduction are relatively mature in late gestation. The study demonstrates that radiotelemetry can be successfully used to assess fetal cardiac function, in particular conduction, through the process of labor and delivery, and may therefore be a useful tool for study of peripartum cardiac events.

Background Assessment of pressure recovery adjusted indexed aortic valve area (AVAi) – energy loss index (ELI) – has been shown of prognostic interest for patients with asymptomatic and/or mild aortic stenosis (AS), but limited data are available in the setting of low gradient aortic stenosis (LG-AS). Purpose We hypothesized that among patients with LG-AS and preserved left ventricular ejection fraction (LVEF), reclassification of AS severity as moderate by pressure recovery adjusted indexed aortic valve area (AVAi) may identify a subgroup of patients with a better outcome. Methods A total of 379 patients with LG-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. Results One hundred and forty eight patients (39%) were reclassified as moderate AS by ELI. Reclassification as moderate AS was independently associated with absence of coronary artery disease, decreased body surface area, normal flow status, and decreased left ventricular mass index (all P Fig. 1 ). 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.

BACKGROUND: Invasive assessment of coronary physiology (IACP) offers important prognostic insights in ST-segment elevation myocardial infarction (STEMI) but the dynamics of coronary recovery are poorly understood. OBJECTIVES: This study sought to examine the evolution of coronary flow reserve (CFR), index of microcirculatory resistance (IMR), ratio of distal coronary pressure (Pd) to mean aortic pressure (Pa), and fractional flow reserve (FFR) in patients undergoing primary percutaneous coronary intervention (PPCI). METHODS: 82 patients with STEMI underwent IACP at PPCI. Repeat IACP was performed in 61 patients (74%) at day 1 and in 46 patients (56%) at 6 months. Contrast-enhanced cardiac magnetic resonance imaging (CMR) was performed in 45 patients (55%) at day 1 and in 41 patients (50%) at 6 months. Changes in IACP were compared between patients with and without microvascular obstruction (MVO) on CMR. RESULTS: MVO was present in 21 of 45 patients (47%). Patients with MVO had lower CFR at PPCI and day 1 (p < 0.05) and a trend toward higher IMR values (p = 0.07). At 6 months, CFR and IMR were not significantly different between the groups. Baseline flow and Pd/Pa remained stable over time but FFR reduced significantly between PPCI and 6 months (p = 0.008); this reduction was mainly observed in patients with MVO (p = 0.006) but not in those without MVO (p = 0.21). CONCLUSIONS: In PPCI-treated patients with STEMI, coronary microcirculation begins to recover within 24 h and recovery progresses further by 6 months. FFR significantly reduces from baseline to 6 months. The presence of MVO indicates a highly dysfunctional microcirculation.

Using the intrinsic optical properties of collagen and elastin, two-photon microscopy was applied to evaluate the three-dimensional (3D) macromolecular structural development of the mouse thoracic aorta from birth to 60 days old. Baseline development was established in the Scavenger Receptor Class B Type I-Deficient, Hypomorphic Apolipoprotein ER61 (SR-BI KO/ApoeR61h/h) mouse in preparation for modeling atherosclerosis. Precise dissection enabled direct observation of the artery wall in situ. En-face, optical sectioning of the aorta provided a novel assessment of the macromolecular structural development. During aortic development, the undulating lamellar elastin layers compressed consistent with the increases in mean aortic pressure with age. In parallel, a net increase in overall wall thickness ( p

Although prior studies showed mean aortic valve pressure gradient (mAoVpg) dramatically drops in patients with severe aortic stenosis following Transcatheter Aortic Valve Replacement (TAVR) with different valve types; it is not well known if this drop in mAoVpg is sustained through the years after

Background Aortic valve replacement (AVR) remains the gold standard treatment for symptomatic severe aortic stenosis (AS). For the past 10 years, transcatheter aortic valve implantation (TAVI) has been applied in patients with high surgical mortality and morbidity risks. The preliminary results of our TAVI patients are presented in this study. Methods Ten high-risk patients with severe AS, for AVR, were referred and accepted for TAVI in the 6 month period from May 2010 to October 2010. The patient age, logistic EuroSCORE, femoral arterial diameter, aorta annulus size, aorta valve area (AVA), mean aortic pressure gradient (MPG), as well as coronary angiography results were all collected. Six patients were treated via the transapical approach in March 2010, whereas the other four were treated with the transfemoral approach, according to their femoral artery diameter and arterial quality. This study focuses on the immediate, 1 month, 3 month, and 1 year results of TAVI. Results The average age of the 10 patients receiving TAVI was 81.5 years. The mean calculated EuroSCORE was 28.3 ± 7.9%. The mean AVA was 0.61 ± 0.19 cm 2 . The MPG was 48 ± 16 mmHg. The surgical technical success achieved 100%. There was no reported moderate to severe postoperative paravalvular aortic regurgitation, permanent complete atrioventricular block, major access site complication, or embolic stroke. Chronic renal failure, which necessitated permanent hemodialysis, developed in 10% of the patients. One acute myocardial infarction and one case of pneumonia developed postoperatively. The AVA was increased by 251%, whereas the MPG was decreased by 80% at the 3 month follow-up. The 30-day mortality rate was 10%. The all-cause 1-year mortality rate was 20%. Conclusion This new technique and device requires greater caution and needs more practice to accumulate sufficient experience. The studied patients were very fragile, due to old age and multiple comorbidities. Our results are similar to findings of multicenter trials. With careful patient screening and selection, TAVI can be a promising treatment for high-risk severe AS patients.

During the past 2 decades, the dynamic nature of valvular heart disease has become a recognized phenomenon. Changes in loading conditions, heart rate, and ventricular contractility that occur with exercise can alter the physiological effects of valvular disease.1,2 Disparity between resting evaluation of valve dysfunction and patient symptoms is not uncommon. Stress echocardiography (SE) has emerged as a modality able to provide new diagnostic information by identifying dynamic changes in the severity of valve stenosis on exertion responsible for symptoms and evaluate the severity of valve disease in altered flow states.3 This review seeks to review critically the existing evidence base, identify new emerging prognostic markers, evaluate their role in clinical practice, and identify future directions for research. The clinical scenarios where SE aids diagnosis and has prognostic value include the evaluation of asymptomatic severe aortic stenosis (AS), low-flow (LF), low-gradient (LG) AS, and moderate AS with symptoms (Table). View this table: Table. Clinical Use of Stress Echocardiography in Stenotic Valvular Heart Disease The prognosis of patients with symptomatic, severe AS is dismal.4 The prognosis for those who are asymptomatic is more favorable with a

To avoid aggressive fluid resuscitation during hemorrhagic shock, fluid resuscitation is best guided by a specific measurement of tissue perfusion. We investigated whether fluid resuscitation guided by sublingual PCO2 would reduce the amount of resuscitation fluid without compromising the outcomes of hemorrhagic shock. Ten male domestic pigs weighing between 34 and 37 kg were used. Forty-five percent of estimated blood volume was removed during an interval of 1 h. The animals were then randomized to receive fluid resuscitation based on either sublingual PCO2 or blood pressure (BP). In the sublingual PCO2-guided group, resuscitation was initiated when sublingual PCO2 exceeded 70 Torr and stopped when it decreased to 50 Torr. In the BP-guided group, resuscitation was initiated when mean aortic pressure decreased to 60 mmHg and stopped when it increased to 90 mmHg. First, Ringer's lactate solution (RLS) of 30 mL kg was administered; subsequently, the shed blood was transfused if sublingual PCO2 remained greater than 50 Torr in the sublingual PCO2-guided group or mean aortic pressure was less than 90 mmHg in the BP-guided group. All the animals were monitored for 4 h and observed for an additional 68 h. In the sublingual PCO2-guided group, fluid resuscitation was required in only 40% of the animals. In addition, a significantly lower volume of RLS (170 ± 239 mL, P = 0.005 vs. BP-guided group) was administered without the need for blood infusion in this group. However, in the BP-guided group, all the animals required a significantly larger volume of fluid (955 ± 381 mL), including both RLS and blood. There were no differences in postresuscitation tissue microcirculation, myocardial and neurologic function, and 72-h survival between groups. During hemorrhagic shock, fluid resuscitation guided by sublingual PCO2 significantly reduced the amount of resuscitation fluid without compromising the outcomes of hemorrhagic shock.

Background The aim of this study was to investigate the impact of varying hemodynamic conditions on fractional flow reserve (ratio of pressure distal [P d ] and proximal [P a ] to stenosis under hyperemia) in an in vitro setting. Failure to achieve maximal hyperemia and the choice of hyperemic agents may have differential effects on coronary hemodynamics and, consequently, on the determination of fractional flow reserve. Methods and Results An in vitro flow system was developed to experimentally model the physiological coronary circulation as flow‐dependent stenosis resistance in series with variable downstream resistance. Five idealized models with 30% to 70% diameter stenosis severity were fabricated using VeroClear rigid material in an Objet260 Connex printer. Mean aortic pressure was maintained at 7 levels (60–140 mm Hg) from hypotension to hypertension using a needle valve that mimicked adjustable microcirculatory resistance. A range of physiological flow rates was applied by a steady flow pump and titrated by a flow sensor. The pressure drop and the pressure ratio (P d /P a ) were assessed for the 7 levels of aortic pressure and differing flow rates. The in vitro experimental data were coupled with pressure–flow relationships from clinical data for populations with and without myocardial infarction, respectively, to evaluate fractional flow reserve. The curve for pressure ratio and flow rate demonstrated a quadratic relationship with a decreasing slope. The absolute decrease in fractional flow reserve in the group without myocardial infarction (with myocardial infarction) was on the order of 0.03 (0.02), 0.05 (0.02), 0.07 (0.05), 0.17 (0.13) and 0.20 (0.24), respectively, for 30%, 40%, 50%, 60%, and 70% diameter stenosis, for an increase in aortic pressure from 60 to 140 mm Hg. Conclusions The fractional flow reserve value, an index of physiological stenosis significance, was observed to decrease with increasing aortic pressure for a given stenosis in this idealized in vitro experiment for vascular groups with and without myocardial infarction.

Purpose The aim of this study was to investigate the effects of the combination of chest compressions and interposed abdominal compressions (IAC-CPR) in a swine model of ventricular fibrillation (VF). Methods Twenty healthy female Landrace-Large White pigs were the study subjects. At the end of the eighth minute of VF, animals in the control group (Group A) received chest compressions at a rate of 100/min, while animals in the experimental group received chest compressions and simultaneous interposed abdominal compressions (CC-IAC – Group B), both at a rate of 100/min. The primary end point of the experiment was return of spontaneous circulation (ROSC). Secondary outcomes were 48-h survival rate and 48-h neurologic outcome. Results Six animals (60%) from Group A and 9 animals (90%) from Group B achieved ROSC (P=.121). There was a statistically significant difference in systolic aortic pressure, mean aortic pressure, right atrial pressures, and end-tidal carbon dioxide (ETCO 2 ) between the two groups during the first cycle of CPR, while during the second cycle, diastolic aortic pressure was significantly higher in Group B. Coronary perfusion pressure (CPP) values in group B were significantly higher compared with those in Group A during the first and second cycle of CPR. Neurologic examination was statistically significantly better in Group B (75.00±10.00 vs. 90.00±10.00, P=.037). Conclusion ROSC did not differ statistically significant in the IAC-CPR compared to the CPR group only, while CPP was significantly higher in IAC-CPR–treated animals.

Elevated central venous pressure is a major cause of morbidity and mortality after the Fontan operation. The difference between mean circulatory filling pressure and central venous pressure, a driving force of venous return, is important in determining dynamic changes in central venous pressure in response to changes in ventricular properties or loading conditions. Thus, noninvasive central venous pressure and mean circulatory filling pressure estimation may contribute to optimal management in patients undergoing the Fontan operation. We tested the hypothesis that central venous pressure and mean circulatory filling pressure in those undergoing the Fontan operation can be simply estimated using peripheral venous pressure and arm equilibrium pressure, respectively.This study included 30 patients after the Fontan operation who underwent cardiac catheterization (median 8.6, 3.4-42 years). Peripheral venous pressure was measured at the peripheral vein in the upper extremities. Mean circulatory filling pressure was calculated by the changes of arterial pressure and central venous pressure during the Valsalva maneuver. Arm equilibrium pressure was measured as equilibrated venous pressure by rapidly inflating a blood pressure cuff to 200 mm Hg.Central venous pressure and peripheral venous pressure were highly correlated (central venous pressure = 1.6 + 0.68 × peripheral venous pressure, R = 0.86, P .0001). Stepwise multivariable regression analysis showed that only peripheral venous pressure was a significant determinant of central venous pressure. Central venous pressure was accurately estimated using regression after volume loading by contrast injection (R = 0.82, P .0001). In addition, arm equilibrium pressure measurements were highly reproducible and robustly reflected invasively measured mean circulatory filling pressure (mean circulatory filling pressure = 9.1 + 0.63 × arm equilibrium pressure, R = 0.88, P .0001).Central venous pressure and mean circulatory filling pressure can be noninvasively estimated by peripheral venous pressure and arm equilibrium pressure, respectively. This should help clarify unidentified Fontan pathophysiology and the mechanisms of Fontan failure progression, thereby helping construct effective tailor-made approaches to prevent Fontan failure.

IMR is useful for assessing the microvascular dysfunction after primary percutaneous coronary intervention (PCI). It remains unknown whether index of microcirculatory resistance (IMR) reflects the functional outcome in patients with anterior myocardial infarction (AMI) with or without microvascular obstruction (MO).This study was performed to evaluate the clinical value of the IMR for assessing myocardial injury and predicting microvascular functional recovery in patients with AMI undergoing primary PCI. We enrolled 34 patients with first anterior AMI. After successful primary PCI, the mean distal coronary artery pressure (P(a)), coronary wedge pressure (P(cw)), mean aortic pressure (P(a)), mean transit time (T(mn)), and IMR (P(d)* hyperemic T(mn)) were measured. The presence and extent of MO were measured using cardiac magnetic resonance image (MRI). All patients underwent follow-up echocardiography after 6 months. We divided the patients into two groups according to the existence of MO (present; n = 16, absent; n = 18) on MRI. The extent of MO correlated with IMR (r = 0.754; P < 0.001), P(cw) (r = 0.404; P = 0.031), and P(cw)/P(d) of infarct-related arteries (r = 0.502; P = 0.016). The IMR was significantly correlated with the ΔRegional wall motion score index (r = -0.61, P < 0.01) and ΔLeft ventricular ejection fraction (r = -0.52, P < 0.01), implying a higher IMR is associated with worse functional improvement. Therefore, Intracoronary wedge pressures and IMR, as parameters for specific and quantitative assessment of coronary microvascular dysfunction, are reliable on-site predictors of short-term myocardial viability and Left ventricle functional recovery in patients undergoing primary PCI for AMI.

Objectives The aim of this study was to assess the validity of measuring fractional flow reserve (FFR) of the left main (LM) coronary artery in the setting of concomitant left anterior descending (LAD) or left circumflex (LCX) stenoses. Background The theoretical impact of a stenosis in the LAD on the FFR assessment of intermediate LM disease with the pressure wire in an unobstructed LCX is currently unknown. Methods A previously validated in vitro model of the coronary circulation was used to create a fixed intermediate stenosis of the LM and a variable downstream LAD or LCX stenosis. The true LM FFR (FFRLM true), with no concomitant downstream disease, was compared to the apparent LM FFR (FFRLM apparent), with concomitant downstream disease measured with different degrees of LAD or LCX disease. Additionally, an equation based on a resistors model was derived to predict the effect of downstream stenosis on LM FFR (FFRLM predicted). Results In the setting of isolated moderate LM disease (FFR 0.72 ± 0.08), mild to moderate proximal LAD or LCX lesions did not significantly affect LM FFR. Lesions with a composite FFR (LM + downstream disease) ≥0.65 resulted in an FFRLM apparent that was not significantly different from FFRLM true (0.76 ± 0.06 vs. 0.76 ± 0.05, p = 0.124). Our equation for FFRLM predicted accurately modeled the effects of concomitant disease (r = 0.95, p Conclusions These data suggest that in the presence of proximal mild to moderate LAD or LCX disease, LM FFR can be reliably measured with the pressure wire placed in the uninvolved epicardial artery.

The mechanism of aortic pulse pressure decline induced by acute rapid ventricular pacing remains incompletely understood. It has been ascribed to changes in stroke volume or aortic compliance. This becomes more complicated by the dependence of aortic compliance on the level of the mean aortic pressure as well as the aortic wall properties. To test the role of such mechanical factors, aortic pressure-diameter hemodynamics, derived from simultaneous tip-micromanometer aortic pressure recordings and high-fidelity ultrasonic intravascular aortic diameter recordings, were measured in 15 normal subjects during and after abrupt cessation of rapid ventricular pacing (up to 160 bpm). Immediately after terminating the pacing, diastolic aortic pressure declined (-9%, from 87.4 +/- 1.2 to 79.5 +/- 1.7 mmHg, P0.0001) while systolic aortic pressure increased (+19%, from 109.5 +/- 1.6 to 130.1 +/- 2.8 mmHg, P0.0001). Thus, pulse pressure increased from 22.1 +/- 2.2 to 50.6 +/- 3.1 mmHg, P0.0001. To quantify systolic and diastolic aortic pressure differences we compared the first postpaced beat (a) and the last paced beat (b). To estimate what the aortic pressure would have been for the paced beats had the aortic diameter differences due to the different heart rate not occurred we calculated the theoretical pressure of the paced beat P(b) = E(b). D(a), where E(b) was the instantaneous aortic elastance of the paced beat and D(a) was the aortic diameter for the postpaced beat. The corrected pressure difference was then calculated by the following: DeltaP(cor) = (D(a). E(b)) - P(a). It was found that systolic DeltaP(cor) was 25% of systolic DeltaP(raw) and diastolic DeltaP(cor) was 89% of diastolic DeltaP(raw). DeltaP(raw) was the pressure difference between paced and spontaneous beat measured from the raw data. DeltaP(cor) indicates the portion of DeltaP(raw) that results from a change in aortic stiffness as a consequence of viscous behavior or aorto-ventricular coupling. These data indicate that the majority of diastolic pressure decline after pacing was terminated, may reflect a change in aortic stiffness while the majority of systolic pressure rise, and may be attributable to differences in hemodynamics alone.

The basal features of the coronary circulation, including coronary reserve, were assessed in 12 nonrejecting heart transplant recipients and compared to similar data obtained in 10 innervated subjects. Coronary sinus blood flow (CSBF) was determined by thermodilution, and coronary reserve was measured as the increment in flow after maximal coronary vasodilatation induced by 10 mg intracoronary papaverine. Heart rate and mean aortic pressure were significantly higher in the transplanted group. Basally, transplanted patients showed lower coronary resistance (0.65 ± 0.12 vs 0.90 ± 0.24 mmHg/ml/minute,p

Assessment of the functional significance of left anterior descending coronary artery (LAD) stenosis of intermediate severity (50%-70% diameter stenosis) is challenging. The aim of this study was to compare the value of noninvasive coronary flow reserve (CFR) with that of invasive fractional flow reserve (FFR) in the setting of LAD stenosis of angiographic intermediate severity.Fifty stable consecutive patients (mean age, 63 ± 13 years; 11 women; mean left ventricular ejection fraction, 61 ± 10%) with angiographic proximal LAD stenoses of intermediate severity (55.5 ± 5% diameter stenosis on quantitative coronary angiography), no previous anterior myocardial infarction, and various vascular risk factors were prospectively studied. They underwent FFR assessment with intracoronary bolus adenosine (150 μg), and CFR assessment using intravenous adenosine (140 μg/kg/min over 2 min) in the distal part of the LAD on the same day in nearly all patients. CFR was defined as hyperemic peak diastolic LAD flow velocity divided by baseline flow velocity (normal value2), and FFR was defined as distal pressure divided by mean aortic pressure during maximal hyperemia (normal value0.8).The mean FFR and CFR were 0.84 ± 0.07 and 2.7 ± 0.75, respectively, in the whole population. Concordant results between FFR and CFR were seen in 44 patients (88%) and discordant results in six patients (12%). There was a significant correlation between CFR and FFR (r = 0.59, P.01). A better correlation was found between FFR and percentage LAD diameter stenosis, and lesion length (all P values.05), than between CFR and the same anatomic markers of stenosis severity (all P values = NS). The sensitivity, specificity, and positive and negative predictive values of CFR2 to detect a nonsignificant lesion defined by normal FFR were 95%, 69%, 90%, and 82%, respectively.In patients with LAD stenosis of intermediate severity, discordant results between noninvasive CFR and FFR were not unusual, and the anatomic determinants of the stenosis were better correlated to FFR than to CFR. However, CFR, which is a global evaluation of the coronary tree, has very high sensitivity to detect a nonsignificant lesion, despite the high prevalence of vascular risk factors.