Giedrius Davidavicius

Fractional Flow Reserve for the Assessment of Nonculprit Coronary Artery Stenoses in Patients With Acute Myocardial Infarction

OBJECTIVES We investigated the reliability of fractional flow reserve (FFR) of nonculprit coronary stenoses during percutaneous coronary intervention (PCI) in acute myocardial infarction. BACKGROUND Assessing the hemodynamic severity of the nonculprit coronary artery stenoses at the acute phase of a myocardial infarction could improve risk stratification and shorten the diagnostic work-up. METHODS One hundred one patients undergoing PCI for an acute myocardial infarction (n = 75 with ST-segment elevation myocardial infarction [STEMI], and n = 26 with non-ST-segment elevation myocardial infarction) were prospectively recruited. The FFR measurements in 112 nonculprit stenoses were obtained immediately after PCI of the culprit stenosis and were repeated 35 ± 4 days later. In addition, left ventricular ejection fraction, quantitative coronary angiographic measurements of the nonculprit stenoses, Thrombolysis In Myocardial Infarction (TIMI) flow, corrected TIMI frame count (cTFC), and the index of microcirculatory resistance (n = 14) of the nonculprit vessels were assessed in the acute phase and at control angiogram. RESULTS The FFR value of the nonculprit stenoses did not change between the acute and follow-up (0.77 ± 0.13 vs. 0.77 ± 0.13, respectively, p = NS). In only 2 patients, the FFR value was higher than 0.8 at the acute phase and lower than 0.75 at follow-up. The TIMI flow, cTFC, percentage diameter stenosis, minimum lumen diameter, and index of microcirculatory resistance did not change. Left ventricular ejection fraction increased significantly in patients with STEMI (from 54 ± 13% to 57 ± 13%, p = 0.03). CONCLUSIONS During the acute phase of acute coronary syndromes, the severity of nonculprit coronary artery stenoses can reliably be assessed by FFR. This allows a decision about the need for additional revascularization and might contribute to a better risk stratification.

Translesional Pressure Gradients to Predict Blood Pressure Response After Renal Artery Stenting in Patients With Renovascular Hypertension

Background—In previous studies on the effect of renal stenting on arterial hypertension, patients were selected mainly on the basis of angiographic parameters of the renal artery stenosis. The aim of the present study was to evaluate whether translesional pressure gradients could identify the patients with renal artery stenosis who might benefit from stenting. Methods and Results—A total of 53 consecutive hypertensive patients with unilateral RAS scheduled for renal artery intervention were recruited. Transstenotic pressure gradients were measured at baseline and during maximal hyperemia, before renal artery stenting. Twenty-four-hour ambulatory blood pressure measurements were performed in all patients before and 3 months after the intervention. Average reductions in systolic blood pressure and diastolic blood pressure at follow-up were −20±30 mm Hg and −2±12 mm Hg, respectively. At multivariate analysis, dopamine-induced mean gradient was the only independent predictor of the variations of both systolic blood pressure (regression coefficient=−4.03, standard error=1.11; P<0.001) and diastolic blood pressure (regression coefficient=−3.11, standard error=1.20; P=0.009). Patients who showed a decline in systolic blood pressure from the baseline value >20 mm Hg were considered as “responders.” The optimal cutoff for identification of “responders” was a dopamine-induced mean gradient ≥20 mm Hg (area under the curve, 0.77; 95% confidence interval, 0.64 to 0.90; P=0.001). Conclusions—A dopamine-induced mean pressure gradient of ≥20 mm Hg is highly predictive of arterial hypertension improvement after renal stenting, and therefore this measurement is useful for appropriate selection of patients with arterial hypertension.

Periprocedural and Short-Term Outcomes of Transfemoral Transcatheter Aortic Valve Implantation With the Sapien XT as Compared With the Edwards Sapien Valve

OBJECTIVES The aim of this study was to analyze the short-term outcomes after transcatheter aortic valve implantation with the Edwards Sapien THV (ESV), compared with the Sapien XT THV (SXT) (Edwards Lifesciences, Irvine, California). BACKGROUND The SXT has been recently commercialized in Europe, but there are no studies analyzing the efficacy and safety of SXT, compared with ESV. METHODS All consecutive patients (n = 120) who underwent transcatheter aortic valve implantation in our center via the transfemoral approach with either ESV (n = 66) or SXT (n = 54). Valve Academic Research Consortium endpoints were used. RESULTS Mean age was 80 ± 8 years, and mean Logistic-European System for Cardiac Operative Risk Evaluation was 24.9 ± 17.0. The ilio-femoral artery minimal lumen diameter was smaller in patients treated with the SXT (7.27 ± 1.09 mm vs. 7.94 ± 1.08 mm, p = 0.002). Device success was high in both groups (96.3% vs. 92.4%, p = 0.45). Major vascular events were 3-fold lower in the SXT group (11.1% vs. 33.3%, relative risk: 0.40, 95% confidence interval: 0.28 to 0.57; p = 0.004). Life-threatening and major bleeding events were not significantly different between groups (18.5% vs. 27.3% and 35.2% vs. 40.9%, respectively). The SXT group had a lower 30-day Valve Academic Research Consortium combined safety endpoint (20.4% vs. 45.5%; relative risk: 0.44, 95% confidence interval: 0.24 to 0.80; p = 0.004). The 30-day mortality was 1.7% (n = 2). At 30 days, mean transaortic gradient was approximately 10 mm Hg in both groups and the aortic regurgitation was mild-to-moderate in 70.2% of SXT and 76.3% of ESV. CONCLUSIONS The new SXT valve has the same short-term performance as the ESV but seems to be associated with a lower risk of major vascular complications and thus has a broader clinical application.

Quantitative assessment of coronary microvascular function in patients with and without epicardial atherosclerosis

AIMS: The influence of atherosclerosis and its risk factors on coronary microvascular function remain unclear as current methods of assessing microvascular function do not specifically test the microcirculation in isolation. We examined the influence of epicardial vessel atherosclerosis on coronary microvascular function using the index of myocardial resistance (IMR). METHODS AND RESULTS: IMR (a measure of microvascular function) and fractional flow reserve (FFR, a measure of the epicardial compartment) were measured in 143 coronary arteries (116 patients). Fifteen patients (22 arteries, mean age 48+/-16 years) had no clinical evidence of atherosclerosis (control group). One hundred and one patients (121 arteries, mean age 63+/-11 years) had established atherosclerosis and multiple cardiovascular risk factors (atheroma group). Mean IMR in the control group (19+/-5, range 8-28) was significantly lower than in the atheroma group (25+/-13, range 6-75) (P

Hybrid Revascularization Strategy A Pilot Study on the Association of Robotically Enhanced Minimally Invasive Direct Coronary Artery Bypass Surgery and Fractional Flow Reserve-Guided Percutaneous Coronary Intervention

Background—Robotically enhanced minimally invasive direct coronary artery bypass (RE-MIDCAB) graft of the left internal mammary artery to the left anterior descending coronary artery (LAD) and/or the first diagonal branch might be the least traumatic surgical revascularization approach available so far. When combined with fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) in the non-LAD vessels, this “hybrid” strategy takes advantage of the survival benefit conferred by the internal mammary artery graft to the LAD while providing the patients with a truly minimally invasive, functionally complete revascularization. Methods and Results—Twenty patients with multivessel disease were selected to undergo combined PCI and RE-MIDCAB because they had a lesion amenable to PCI in the right and/or the left circumflex coronary artery and a lesion in the LAD and/or the first diagonal branch that was considered less than ideal for PCI. PCI was actually performed only when FFR was <0.80 (“provisional PCI”). In 7 stenoses, FFR was >0.80 and the planned PCI was not performed. Surgery was performed before provisional PCI in 6 cases. An angiogram was obtained in all patients before discharge, and a complete clinical follow-up including a stress test was obtained in all patients after a mean of 12 months. There were no significant intraoperative complications, conversions to cardiopulmonary bypass, or reinterventions for bleeding. At early control angiogram, 2 moderate stenoses just proximal to anastomosis were observed, both with normal run-off. After 12 months there were no objective signs of ischemia at stress testing. After an average follow-up of 19±10 months there were no deaths, myocardial infarctions, or repeat revascularizations. Conclusion—A hybrid strategy combining FFR-guided PCI and RE-MIDCAB seems safe and provides selected patients with a functionally complete revascularization with minimal surgical trauma and excellent clinical outcomes.

The accordion phenomenon

A 65 year old man, with a history of non-insulin dependent diabetes, arterial hypertension, hyperlipidaemia, and coronary artery bypass graft surgery, presented with crescendo angina. Salient features on angiography include a normal left ventricular function (ejection fraction 82%), occlusion of the mid left anterior descending (LAD) artery, a 70% proximal stenosis in the first marginal, …

Development of cloud services for patient-specific simulations of blood flows through aortic valves

The paper presents the development of cloud software services for patient-specific computational analysis of blood flows through the aortic valve on a private university cloud. The main focus is on the software service level at the top of the provided computational platform. Blood flow through the aortic valve was considered as a pilot application of the OpenStack cloud infrastructure. A modelling software environment based on ANSYS Fluent was developed as a software service (SaaS) for the numerical analysis of low flow, low pressure gradient aortic stenosis. Segmentation software services were designed to deal with the patient-specific issues of the computational analysis. User-friendly management tools were developed using Apache jclouds API to enhance the management of OpenStack cloud infrastructure and to increase the accessibility of the required software. The performance of the cloud infrastructure was assessed by testing CPU, memory bandwidth, disk I/O and the developed software service for medical computations. The performance measured on Xen hardware virtual machines, KVM virtual machines and Docker containers were compared with the performance obtained by using the native hardware.

Resultados a muy largo plazo tras la implantación de stents liberadores de fármacos en la estenosis de arteria coronaria principal izquierda no protegida: experiencia de un centro

INTRODUCTION AND OBJECTIVES Encouraging results at long-term follow-up have been reported from non-randomized registries and randomized trials following percutaneous coronary intervention with drug-eluting stent implantation for unprotected left main stenosis. However, information on very long-term (>5-year) outcomes is limited. The aim of this study was to assess the very long-term outcomes (6-years) following drug-eluting stent implantation for left main disease. METHODS All consecutive patients with unprotected left main stenosis electively treated with drug-eluting stent implantation, between March 2002 and May 2005, were analyzed according to the location of the left main lesion (distal bifurcation vs ostial/body). RESULTS The study included 149 patients: 113 with distal bifurcation and 36 with ostial/body lesion. Triple-vessel disease was significantly higher in the distal than in the ostial/body group (52.2% vs 33.2%, P=.05). At 6-years of follow-up, the cumulative major adverse cardiovascular event rate was 41.6% (45.1% distal vs 30.6% ostial/body, P=0.1), including 18.8% any death (22.1% distal vs 8.3% ostial/body, P=.08), 3.4% myocardial infarction (3.5% distal vs 2.8% ostial/body, P=1), and 15.4% target lesion revascularization (18.6% distal vs 5.6% ostial/body, P=.06). The composite of cardiac death and myocardial infarction was 10.7% (13.3% distal vs 2.8% ostial/body, P=.1) while the definite/probable stent thrombosis rate was 1.4% (all in the distal group). CONCLUSIONS At 6-year clinical follow-up, percutaneous coronary intervention with drug-eluting stent implantation for unprotected left main disease was associated with acceptable rates of cardiac death, myocardial infarction and stent thrombosis. Favorable long-term outcomes in ostial/body lesions compared to distal bifurcation lesions were confirmed at long-term clinical follow-up.

On Efficiency of Parallel Solvers for the Blood Flow through Aortic Valve

Mathematical modelling of cardiac haemodynamics presents a great challenge to the computational scientists due to numerous numerical issues and required computational resources. In this paper, we study the parallel performance of 3D simulation software for the blood flow through the aortic valve. The fluid flow problem with the open aortic valve leaflets is formulated and solved in parallel. The choice between the segregated and coupled numerical schemes is discussed and investigated. We present and compare the parallel performance results of both types of parallel solvers. We investigate their strong and weak scalability.

Retrospective analysis of single-center early and midterm results of transapical catheter‑based mitral paravalvular leak closure with a purpose-specific device

Introduction Due to the recent lack of definitions to establish the severity of paravalvular leak (PVL) and endpoints for its treatment, the effectiveness and safety of a new device for PVL closure have not been comprehensively analyzed. Aim To analyze a single center’s experience of mitral PVL closure in a surgical transapical catheter-based fashion with a purpose-specific device. Material and methods This is a retrospective cohort study of patients following transapical catheter-based mitral PVL closure with a purpose-specific device. Data were analyzed at baseline, perioperatively, at discharge, at six months and annually after the procedure. Results Nineteen patients underwent surgical transapical catheter-based mitral PVL closure with the Occlutech PLD Occluder. Mean follow-up time was 20 ±7 (range: 9–33) months. The patients’ mean age was 64 ±7 years, and 11 (58%) were male. Technical, device and individual patient success at follow-up was achieved in 18 (95%), 16 (84%) and 16 (84%) patients respectively. Median intensive therapy unit stay was one day (1–4) and mean hospital stay was 11 ±4 days. A reduction of paravalvular regurgitation to a mild or lesser degree was achieved in 18 (95%) patients. There were no strokes or myocardial infarctions at follow-up. There were no deaths at 30 days after the procedure. One (5%) patient expired due to progression of heart failure 12 months after surgery. None of the patients required immediate conversion to full sternotomy. Conclusions Surgical transapical catheter-based mitral PVL closure with the Occlutech PLD Occluder is a safe and clinically effective treatment.