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Journal of the American College of Cardiology 10/2012; · 14.16 Impact Factor
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ABSTRACT: Current methods for hypercoagulability panel testing require large blood volumes and long turn-around testing times. A novel microfluidic platform has been designed to perform automated multiplexed hypercoagulability panel testing at near patient, utilizing only a single droplet of blood sample. We test the hypothesis that this novel platform could be utilized to perform specific multiplexed ELISA-based hypercoagulability panel testing for antithrombin III, protein C, protein S and factor VIII antigens, as well as anticardiolipin/human anti-β2-glycoprotein-1 IgG antibodies - on blood samples. Sandwich ELISA was modified by utilizing magnetic beads coated with specific antibodies as the solid phase using florescence readout. Percentage recovery was calculated using four-parameter logistic curves. On-chip ELISA with single factors was compared with multiplex factor ELISA for known concentrations of sample. Blood samples were analyzed on-chip and compared with traditional bench-top assays. Time for multiplexed performance of hypercoagulability panel ELISA on-chip with controls is 72 min. Recovery rates (range 80-120%) for known concentrations of specific factors was not significantly different when assays were performed using a single factor vs. multiplex factor analysis. Assay results were not significantly different between individual assays performed either on bench-top or on-chip with patient blood and/or plasma. Utilizing a novel digital microfluidic platform, we demonstrate the feasibility of automated hypercoagulability panel testing on small volume of plasma and whole blood patient samples with high fidelity. Further investigation is required to test the application of this novel technology at point-of-care clinical settings.
Blood coagulation & fibrinolysis: an international journal in haemostasis and thrombosis 09/2012; · 1.25 Impact Factor
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ABSTRACT: Annuloplasty for functional tricuspid regurgitation may sometimes be ineffective because of chamber dilation and valve tethering. This study compared a novel technique, right ventricle (RV)-papillary muscle approximation, with annuloplasty in experimentally-produced tricuspid regurgitation.
RVs of isolated porcine hearts (n = 10) were statically pressurized, which led to RV dilation and central tricuspid regurgitation. Regurgitant flow was measured with a saline solution-filled column. The head of the anterior papillary muscle was approximated to 4 points on the ventricular septum. Next, a prosthetic ring was implanted, and then RV-papillary muscle approximation was combined. Tricuspid annular dimension, RV geometry, and tricuspid valve tethering were analyzed with 3-dimensional echocardiography.
Tricuspid regurgitation (2270 ± 186 mL/min) was reduced by RV-papillary muscle approximation alone (214 ± 45 mL/min; P < .05) more than by annuloplasty alone (724 ± 166 mL/min; P < .05). Combined RV-papillary muscle approximation and annuloplasty resulted in the least regurgitation (80 ± 39 mL/min). RV-papillary muscle approximation reduced tricuspid septolateral diameter (25%; P < .05), and annular area (23%; P < .05), as did annuloplasty. RV-papillary muscle approximation also reduced RV sphericity index (33%; P < .05) and tricuspid tethering height (54%; P < .05), whereas annuloplasty did not. Direction of RV-papillary muscle approximation did not independently affect outcomes.
This ex vivo study suggests that RV-papillary muscle approximation potentially repairs tricuspid regurgitation better than annuloplasty by improving ventricular sphericity and valve tethering as well as annular dimension.
The Journal of thoracic and cardiovascular surgery 02/2012; 144(1):235-42. · 3.41 Impact Factor
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ABSTRACT: The most common reason for late surgical reintervention after repair of complete atrioventricular canal defects is the development of left atrioventricular valve regurgitation. We sought to determine the changes in left atrioventricular valve geometry after surgical repair that may predispose to regurgitation.
Atrioventricular valve measurements were obtained by 2-dimensional echocardiography at 3 different time points (preoperative, early postoperative, and midterm postoperative [6-12 months]). Left atrioventricular valve annulus area and left ventricular volume were calculated; vena contracta of the regurgitant jet orifice was measured. All measurements were normalized relative to an appropriate power of body surface area.
From January 2000 to January 2008, 101 patients with complete atrioventricular canal repair were included. Left atrioventricular valve annulus was noted to remodel from an elliptical shape to a circular shape after surgery. Left atrioventricular valve annulus area increased early postoperatively (systole: 4.1 ± 0.2 cm(2)/m(2) vs 6.1 ± 0.3 cm(2)/m(2), P < .001; diastole: 7.2 ± 0.4 cm(2)/m(2) vs 10.0 ± 0.5 cm(2)/m(2), P < .001, pre- vs postoperative, respectively). This increase was sustained in the midterm postoperative period (systole: 6.1 ± 0.3 cm(2)/m(2), P = .85, vs diastole: 10.0 ± 0.4 cm(2)/m(2), P = .78, early vs midterm postoperative). Left ventricular volume increased in the early and midterm postoperative periods compared with preoperative (systole: 16.9 ± 1.2 mL/m(2) vs 26.2 ± 1.7 mL/m(2), P < .001; diastole: 35.0 ± 2.4 mL/m(2) vs 52.5 ± 3.2 mL/m(2), P < .001).
Complete atrioventricular canal repair leads to left atrioventricular valve annular shape change with increased area and circular shape. The change in left atrioventricular valve annulus shape appeared to be mainly due to increased circumference in the posterior free wall of the annulus. These findings may provide a mechanism for the progression of central regurgitation seen after complete atrioventricular canal repair and a potential solution.
The Journal of thoracic and cardiovascular surgery 11/2011; 143(5):1117-24. · 3.41 Impact Factor
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Victor Bautista-Hernandez,
Mark Scheurer,
Ravi Thiagarajan,
Joshua Salvin,
Frank A Pigula,
Sitaram Emani,
Francis Fynn-Thompson, Hugo Loyola,
Jared Schiff,
Pedro J del Nido,
Emile A Bacha
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ABSTRACT: This study aimed to evaluate clinical outcomes including hemodynamics, right ventricle (RV) function, and tricuspid valve (TV) function in patients with hypoplastic left heart syndrome (HLHS) at midterm after completion of staged palliation based on the source of pulmonary blood flow provided at stage 1. The records of all patients with HLHS who completed Fontan palliation between 2001 and 2007 were retrospectively reviewed. The outcome variables were RV dysfunction, TV, and neo-atrioventricular (neo-AV) regurgitation (from latest echocardiogram), cardiac index (CI), pulmonary vascular resistance (PVR), pulmonary artery pressure (PAp), and right ventricular end-diastolic pressure (RVEDp) (from latest catheterization). Clinical status was obtained from medical records and by contact with the referring cardiologist if necessary. Of 118 patients undergoing a Fontan for HLHS, 116 had a fenestrated lateral tunnel and 2 had an extracardiac conduit. At the time of stage 1 palliation, 36 patients had a right ventricle-to-pulmonary artery (RV-PA) conduit, and 82 patients had a modified Blalock-Taussig shunt (mBTS). All the patients except one who died of sepsis on extracorporeal membrane oxygenation (ECMO) survived the Fontan operation and were discharged home. At a mean follow-up post-Fontan period of 28.4 months (range, 0.16-95.3 months), three patients had died (2 on the transplantation list and 1 from pulmonary vein stenosis), and one patient had the Fontan circulation taken down. No patient had a heart transplantation. A follow-up echocardiogram was performed for 115 patients (after a mean of 15.6 months for RV-PA and 32.1 months for BTS), and 66 patients underwent a post-Fontan catheterization (after a mean of 15.8 months for RV-PA and 29.3 months for BTS). The hemodynamic results for RV-PA conduit versus BTS were a CI of 3.4 ± 0.8 versus 3.4 ± 1.2, a PVR of 1.8 ± 0.7 versus 1.7 ± 0.8, a PAp of 14.3 ± 3.1 versus 14.2 ± 4.5, and an RVEDp of 7.1 ± 3.3 versus 8.9 ± 5.3. No statistically significant differences were found between shunt types regarding survival or degree of RV dysfunction or in terms of neo-AV regurgitation, CI, PVR, PAp, RVEDp, or rhythm problems. Patients in the BTS group required more tricuspid valvuloplasties and had more tricuspid regurgitation at follow-up evaluation. The patients in the RV-PA group had more PA interventions. In conclusion, the contemporary results after Fontan palliation for HLHS were excellent. At the midterm follow-up evaluation, outcomes and hemodynamic data were similar between shunt types. However, the patients in the BTS group exhibited more tricuspid regurgitation, and the patients in the RV-PA group had increased pulmonary artery interventions.
Pediatric Cardiology 02/2011; 32(2):160-6. · 1.30 Impact Factor
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ABSTRACT: Late complications of the Fontan operation represent a significant management challenge. Failing Fontan patients have two modes of presentation: impaired ventricular function (IVF) and those with preserved ventricular function (PVF) but with failing Fontan physiology (protein-losing enteropathy [PLE] and plastic bronchitis [PB]). This study evaluated whether failing Fontan patients referred for heart transplantation had a different outcome based on the mode of presentation.
The medical records of all Fontan patients evaluated for heart transplantation at a single institution from 1994 to 2008 were retrospectively reviewed. Demographic, hemodynamic, and laboratory data were collected. Patients were stratified into an IVF or PVF group by echocardiographic criteria. Descriptive statistics and Kaplan-Meier analysis were used for hypothesis testing.
Thirty-four Fontan patients were evaluated for heart transplantation. According to echo description of systolic function, 18 were categorized as IVF and 16 as PVF. The IVF group had a significantly lower cardiac index and venous oxygen saturation, and significantly higher systemic vascular resistance vs the PVF group (p < 0.05). PLE or PB was present in 13 PVF patients and none in the IVF group. Twenty patients underwent transplantation, with similar rates amongst the IVF and PVF groups. Within 1 year from evaluation, 2 IVG patients and 7 PVF patients had died (p = 0.052).
Failing Fontan patients with PVF have decreased overall survival independent of whether they underwent transplantation. This trend indicates a need to improve the management and timing for transplantation amongst this population.
The Annals of thoracic surgery 08/2009; 88(2):558-63; discussion 563-4. · 3.74 Impact Factor
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ABSTRACT: Stereoscopic vision display technology has been shown to be a useful tool in image-guided surgical interventions. However, the concept has not been applied to 3-dimensional echocardiography-guided cardiac procedures. We evaluated stereoscopic vision display as an aid for intracardiac navigation during 3-dimensional echocardiography-guided beating-heart surgery in a model of atrial septal defect closure.
An atrial septal defect (6 mm) was created in 6 pigs using 3-dimensional echocardiography guidance. The defect was then closed using a catheter-based patch delivery system, and the patch was attached with tissue mini-anchors. Stereoscopic vision was generated with a high-performance volume renderer with stereoscopic glasses. Three-dimensional echocardiography with stereoscopic vision display was compared with 3-dimensional echocardiography with standard display for guidance of surgical repair. Task performance measures for each anchor placement (N = 32 per group) were completion time, trajectory of the tip of the anchor deployment device, and accuracy of the anchor placement.
The mean time of the anchor deployment for stereoscopic vision display group was shorter by 44% compared with the standard display group: 9.7 +/- 0.9 seconds versus 17.2 +/- 0.9 seconds (P < .001). Trajectory tracking of the anchor deployment device tip demonstrated greater navigational accuracy measured by trajectory deviation: 3.8 +/- 0.7 mm versus 6.1 +/- 0.3 mm, 38% improvement (P < .01). Accuracy of anchor placement was not significantly different: 2.3 +/- 0.3 mm for the stereoscopic vision display group versus 2.3 +/- 0.3 mm for the standard display group.
Stereoscopic vision display combined with 3-dimensional echocardiography improved the visualization of 3-dimensional echocardiography ultrasound images, decreased the time required for surgical task completion, and increased the precision of instrument navigation, potentially improving the safety of beating-heart intracardiac surgical interventions.
The Journal of thoracic and cardiovascular surgery 06/2008; 135(6):1334-41. · 3.41 Impact Factor
