St Jude Medical Inc Research Articles

PO-693-05 REMOVAL OF A CHRONICALLY-IMPLANTED LEADLESS VENTRICULAR PACEMAKER AFTER 9-YEARS USING A HIGHLY TORQUE RETRIEVAL CATHETER A CASE REPORT

Leadless cardiac pacemakers (LPs) are an effective and safe alternative to transvenous pacemakers for single-chamber ventricular pacing. However, the feasibility of retrieving and replacing chronically implanted LPs is not well understood. We report a case of LP retrieval and replacement of a 9-year chronically implanted Nanostim LP. N/A An 84 year old woman had a Nanostim LP (St Jude Medical Inc) implanted in December 2012, with good pacing parameters: threshold 0.5 V at 0.4 ms, impedance 500 Ohm, R-wave amplitude 7.5 mV. The parameters remained stable over time until the most recent clinic visit (early November 2021), when interrogation failed - indicating battery end-of-life. One month later, she underwent LP retrieval. Fluoroscopy revealed significant swinging movement of the LP docking button - suggestive that success of retrieval was likely. After femoral venous access, with fluoroscopy + ICE guidance, we used a tri-loop snare LP retrieval catheter (Abbott Inc) designed to be engage the LP in a highly torque-responsive manner. After confirming coaxial alignment between the snare and the docking button, the snare was closed, and locked around the docking button on the proximal end of the LP. After closing the snare, the retrieval catheter was docked with the LP. The protective sleeve was then advanced over the LP to assist with the coaxial alignment between the retrieval catheter docking cap and the LP. Thereafter, the retrieval catheter was rotated counterclockwise to allow the LP to unscrew from the myocardium. After less than 2 minutes, the tri-Loop retrieval catheter snared the docking cap, and the soft protective sleeve was easily advanced over the LP. After two full rotations, and in less then 2 minutes, the LP was released from the RV wall. The explanted LP device had limited adherent tissue ingrowth. During the same procedure, a new LP (Aveir VR; Abbott Inc.) was implanted: acute threshold 1 V/0.4, Impedance 630 ohm and R wave amplitude 9 mV. This case report demonstrates the feasibility of retrieval of even long-term chronically-implanted LPs after 9 years duration. Successful retrieval seems to be related to the combination of i) identifying swinging motion of the LP with fluoroscopy, plus ii) the high torque-responsiveness of the retrieval catheter.

Outcomes after mechanical aortic valve replacement in children and young adults with congenital heart disease

ObjectivesThere are little recent data on the outcomes of mechanical aortic valve replacement (AVR) in children and young adults with congenital aortic valve disease. We sought to review the survival and associated thromboembolic or bleeding complications after mechanical AVR at a single center. MethodsData were retrospectively collected for 121 patients undergoing prosthetic AVR from 2000 to 2014. Kaplan-Meier estimates and Cox proportional hazards were employed. ResultsMedian age at AVR was 16 years (interquartile range, 12-22.8 years). The valves implanted were the St Jude valve (St Jude Medical Inc, St Paul, Minn) in 79 patients (62%), the On-X valve (On-X Life Technologies Inc, Austin, Tex) in 45 patients (35%), and CarboMedics (Sorin SpA, Milan, Italy) in 3 patients (2.4%). Median valve size was 23 mm (range, 21-25 mm). There were 5 early deaths (3.9%). Median follow-up was 5 years (range, 1.6-9.2 years; 600 patient-years). There were 14 deaths during follow-up. Survival was 90.6% ± 2.8% at 1 year, 85.4% ± 3.7% at 5 years, and 81.5% ± 4.5% at 10 years. Freedom from aortic valve reoperation was 98% ± 1.4% at 1 and 5 years, 91.5% ± 3.9% at 7 years, and 78.4% ± 6.9% at 10 years and at latest follow-up. Univariable analysis identified younger age, lower weight, and use of a 16-mm CarboMedics valve as predictors of reoperation. Valve sizes of 16 or 17 mm have a significantly higher risk of reoperation compared with larger valves (log-rank test, P < .001). At multivariable analysis, only younger age was a significant independent predictor of reoperation (hazard ratio, 0.84; 95% confidence interval, 0.71-0.99; P = .038). All patients were treated with warfarin to a goal international normalized ratio of 2.0 to 3.0. Four patients (3.1%; 0.66% per patient-year) had thromboembolic complications, and 5 patients (3.9%; 0.83% per patient-year) had bleeding events during follow-up. ConclusionsMechanical AVR in patients with congenital heart disease has excellent short- and midterm outcomes. Younger age was an independent predictor of reoperation.

Cost-Effectiveness of Implantable Pulmonary Artery Pressure Monitoring in Chronic Heart Failure

ObjectivesThis study aimed to evaluate the cost-effectiveness of the CardioMEMS (CardioMEMS Heart Failure System, St Jude Medical Inc, Atlanta, Georgia) device in patients with chronic heart failure. BackgroundThe CardioMEMS device, an implantable pulmonary artery pressure monitor, was shown to reduce hospitalizations for heart failure and improve quality of life in the CHAMPION (CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients) trial. MethodsWe developed a Markov model to determine the hospitalization, survival, quality of life, cost, and incremental cost-effectiveness ratio of CardioMEMS implantation compared with usual care among a CHAMPION trial cohort of patients with heart failure. We obtained event rates and utilities from published trial data; we used costs from literature estimates and Medicare reimbursement data. We performed subgroup analyses of preserved and reduced ejection fraction and an exploratory analysis in a lower-risk cohort on the basis of the CHARM (Candesartan in Heart failure: Reduction in Mortality and Morbidity) trials. ResultsCardioMEMS reduced lifetime hospitalizations (2.18 vs. 3.12), increased quality-adjusted life-years (QALYs) (2.74 vs. 2.46), and increased costs ($176,648 vs. $156,569), thus yielding a cost of $71,462 per QALY gained and $48,054 per life-year gained. The cost per QALY gained was $82,301 in patients with reduced ejection fraction and $47,768 in those with preserved ejection fraction. In the lower-risk CHARM cohort, the device would need to reduce hospitalizations for heart failure by 41% to cost <$100,000 per QALY gained. The cost-effectiveness was most sensitive to the device’s durability. ConclusionsIn populations similar to that of the CHAMPION trial, the CardioMEMS device is cost-effective if the trial effectiveness is sustained over long periods. Post-marketing surveillance data on durability will further clarify its value.

The effect of postoperative medical treatment on left ventricular mass regression after aortic valve replacement

The study objective was to analyze factors associated with left ventricular mass regression in patients undergoing aortic valve replacement with a newer bioprosthesis, the Trifecta valve pericardial bioprosthesis (St Jude Medical Inc, St Paul, Minn). A total of 444 patients underwent aortic valve replacement with the Trifecta bioprosthesis from 2007 to 2009 at 6 US institutions. The clinical and echocardiographic data of 200 of these patients who had left ventricular hypertrophy and follow-up studies 1 year postoperatively were reviewed and compared to analyze factors affecting left ventricular mass regression. Mean (standard deviation) age of the 200 study patients was 73 (9) years, 66% were men, and 92% had pure or predominant aortic valve stenosis. Complete left ventricular mass regression was observed in 102 patients (51%) by 1 year postoperatively. In univariate analysis, male sex, implantation of larger valves, larger left ventricular end-diastolic volume, and beta-blocker or calcium-channel blocker treatment at dismissal were significantly associated with complete mass regression. In the multivariate model, odds ratios (95% confidence intervals) indicated that male sex (3.38 [1.39-8.26]) and beta-blocker or calcium-channel blocker treatment at dismissal (3.41 [1.40-8.34]) were associated with increased probability of complete left ventricular mass regression. Patients with higher preoperative systolic blood pressure were less likely to have complete left ventricular mass regression (0.98 [0.97-0.99]). Among patients with left ventricular hypertrophy, postoperative treatment with beta-blockers or calcium-channel blockers may enhance mass regression. This highlights the need for close medical follow-up after operation. Labeled valve size was not predictive of left ventricular mass regression.

Suture technique does not affect hemodynamic performance of the small supra-annular Trifecta bioprosthesis

The study objective was to evaluate whether aortic valve replacement with the Trifecta valve (St Jude Medical Inc, St Paul, Minn) using simple sutures produces better hemodynamic performance than valve replacement with noneverting pledget-reinforced sutures. We analyzed prospectively acquired 1-year hemodynamic data of patients with small aortic annulus sizes who were enrolled in a multicenter trial of the Trifecta aortic valve bioprosthesis and underwent aortic valve replacement with a 19-mm or 21-mm bioprosthesis between August 2007 and November 2009. We compared preoperative clinical information and 1-year postoperative hemodynamic data for noneverting pledget-reinforced sutures (group 1) versus everting mattress sutures or simple sutures (group 2). A total of 346 patients underwent aortic valve replacement: 269 in group 1 and 77 in group 2. Preoperative demographic characteristics for the 2 groups were similar. For groups 1 and 2, the mean gradient was 10.4±4.7 mm Hg and 11.1±4.4 mm Hg for 19-mm valves, respectively, and 8.4±3.5 mm Hg and 8.8±3.6 mm Hg for 21-mm valves, respectively; the effective orifice area was 1.40 cm2 and 1.25 cm2 for 19-mm valves, respectively, and 1.57 cm2 and 1.50 cm2 for 21-mm valves, respectively. The rate of severe prosthesis-patient mismatch (indexed effective orifice area≤0.65 cm2/m2) was 18.6% (n=11) and 25% (n=6) for 19-mm valves, respectively, and 10.9% (n=20) and 16.3% (n=8) for 21-mm valves, respectively. The suture method did not affect hemodynamic performance of supra-annular bioprostheses in patients with small aortic annulus sizes. Choice of suture technique should be determined by surgeon experience and local anatomic features.

The St Jude Medical Trifecta aortic pericardial valve: Results from a global, multicenter, prospective clinical study

The St Jude Medical Inc (St Paul, Minn) Trifecta valve is a novel aortic biological prosthesis that incorporates several design features, including a true supra-annular sewing cuff, a stent design that maximizes valve hemodynamics while minimizing leaflet stresses, and an ethanol-based anticalcification technology. This study establishes the safety and early clinical and hemodynamic performance of the Trifecta valve. The Trifecta bioprosthesis was implanted in 1014 eligible patients between 2007 and 2009 at 31 centers. The mean age of the population was 72.5 ± 9.0 years, of whom 650 (64.1%) were male and 364 (35.9%) were female. Eighty-two subjects (8.1%) had undergone previous open surgery. Indications for aortic valve replacement surgery included stenosis in 556 patients (54.8%), regurgitation in 61 patients (6.0%), and mixed pathology in 397 patients (39.2%). The overall follow-up included 844.3 late patient-years. Early (≤ 30 day) mortality occurred in 18 patients (1.8%), and there were 23 late (≥ 31 days) deaths yielding a linearized mortality rate of 2.72% per late patient-year. There were 27 early thromboembolic events, including 8 (0.8%) strokes, 17 (1.7%) reversible neurologic events, and 2 (0.2%) systemic embolic events. There were no instances of early valve thrombosis, endocarditis, or clinically significant hemolysis. There were 16 late thromboembolic events (linearized rate of 1.90% per year of follow-up), including 4 strokes and 12 reversible neurologic events. In total, there were 5 late valve explants, including 1 structural deterioration and 4 prosthetic valve endocarditis cases. Overall, freedom from valve explant was 99.4% at 2 years. At the time of discharge, average mean gradients ranged from 9.3 to 4.1 mm Hg and effective orifice area ranged from 1.58 to 2.50 cm(2) for valve sizes 19 to 29 mm, respectively. The St Jude Medical Trifecta valve is a unique pericardial bioprosthesis with design elements that provide excellent hemodynamic performance while providing ease of implantation. Long-term follow-up continues to confirm the promising results of this innovative bioprosthesis.

In vitro comparison of different mechanical prostheses suitable for replacement of the systemic atrioventricular valve in children

The aim of the present study was to compare the hydrodynamics of 4 different mechanical prostheses fitting the atrioventricular annulus in children. We tested different inverted aortic prostheses with a prosthesis-annulus relationship in the mitral chamber of the Sheffield pulse duplicator (Department of Medical Physics and Clinical Engineering, Royal Hallamshire Hospital, Sheffield, UK), analyzed by comparing the prosthetic housing diameter and the predicted annulus diameter based on body surface area (0.8 and 1 m(2) corresponding to an annulus diameter of 18.8-20.2 mm). The On-X 19 (On-X Life Technologies, Inc, Austin, Tex), SJM Regent 19 (St Jude Medical Inc, St Paul, Minn), Sorin Overline 18 (Sorin Biomedica, Saluggia, Italy), and Medtronic Advantage Supra 19 (Medtronic Inc, Minneapolis, Minn) valves with a housing diameter of 19 to 20 mm were hydrodynamically compared. The tests were carried out at increasing pulse rate of 72, 80, 100, and 120 beats/min for a stroke volume of 20 and 30 mL. Therefore, cardiac output ranged from 1.44 to 3.6 L/min. Regardless of the pulse rate and stroke volume, the Medtronic Advantage Supra valve showed the highest mean diastolic pressure difference at each cardiac output (P<.05). The mean gradients were significantly lower for the Sorin Overline valve regardless of the cardiac output, stroke volume, and pulse rate (P<.05). The effective orifice areas observed followed exactly the same behavior: the lowest for the Medtronic Advantage Supra valve and the highest for the Sorin Overline valve. The Sorin Overline valve showed the highest closure volumes (P<.05), and the On-X prosthesis showed the highest leakage volumes (P<.05). The Sorin Overline valve had the highest total regurgitant volume (P<.05), and the Medtronic Advantage Supra valve had the lowest total regurgitant volume (P<.05). The On-X valve showed the highest total energy loss regardless of the pulse rate at 20 mL of stroke volume, which was comparable to the SJM Regent and Sorin Overline valves at increased stroke volume. The Medtronic Advantage Supra valve showed the lowest total energy loss regardless of cardiac outputs (P<.05). This hydrodynamic evaluation model allowed us to compare the efficiency of currently available valve prostheses suitable for atrioventricular replacement in children. Among these prostheses, the Sorin Overline valve showed the best diastolic performance. On the other hand, for total energy loss, the Medtronic Advantage Supra valve demonstrated excellent performance.

Patient-prosthesis mismatch in the mitral position affects midterm survival and functional status

The definition and incidence of patient-prosthesis mismatch (PPM) in the mitral position are unclear. To determine the impact of PPM on late survival and functional status after mitral valve replacement with a mechanical valve. Between 1992 and 2005, 714 patients (mean [± SD] age 60±10 years) underwent valve replacement with either St Jude (St Jude Medical Inc, USA) (n=295) or Carbomedics (Sulzer Carbomedics Inc, USA) (n=419) valves. There were 52 concomitant procedures (50 tricuspid annuloplasties, 25 foramen oval closures and 20 radiofrequency mazes). The mean clinical follow-up period was 4.4±3.3 years. The severity of PPM was established with cut-off values for an indexed effective orifice area (EOAi) of lower than 1.2 cm(2)⁄m(2), lower than 1.3 cm(2)⁄m(2) and lower than 1.4 cm(2)⁄m(2). Parametric and nonparametric tests were used to determine predictors of outcome. The prevalence of PPM was 3.7%, 10.1% and 23.5% when considering values of lower than 1.2 cm(2)⁄m(2), lower than 1.3 cm(2)⁄m(2) and lower than 1.4 cm(2)⁄m(2), respectively. When considering functional improvement, patients with an EOAi of 1.4 cm(2)⁄m(2) or greater had a better outcome than those with an EOAi of lower than 1.4 cm(2)⁄m(2) (OR 1.98; P=0.03). When building a Cox-proportional hazard model, PPM with an EOAi of less than 1.3 cm(2)⁄m(2) was an independent predictive factor for midterm survival (HR 2.24, P=0.007). Other factors affecting survival were age (HR 1.039), preoperative New York Heart Association class (HR 1.96) and body surface area (HR 0.31). In a large cohort of patients undergoing mitral valve replacement with mechanical prostheses, PPM defined as an EOAi of lower than 1.3 cm(2)⁄m(2) significantly decreased midterm survival. This level of PPM was observed in 10.2% of patients. Patients with an EOAi of 1.4 cm(2)⁄m(2) or greater had greater improvement of their functional status.

Implantable Sensors for Heart Failure

Heart failure (HF) affects more than 5 million Americans, and acute decompensated heart failure (ADHF) has emerged as the leading cause of hospitalization among people over the age of 65 years.1 Importantly, HF is a leading public health concern, and hospitalization expenses related to management of ADHF impose a substantial financial burden on the health care system. Additionally, readmission rates after hospitalization for ADHF may be as high as 50% at 6 months,2 and insights from the ADHERE registry suggest that a majority of patients admitted with ADHF have a history of heart failure.1 These data demonstrate that the majority of patients admitted with ADHF are known to the medical system and to medical providers, thereby creating an opportunity for upstream strategies that may be capable of detecting early HF destabilization and implementing therapies to restabilize the patient and avert hospitalization. The anticipated changes in the health care system—with a focus on bundled payments for disease management—will necessitate robust disease management programs to optimize therapy and minimize recurrent admissions once patients have been diagnosed with HF. Perhaps even more importantly, averting repeat episodes of ADHF is likely to have a stabilizing effect on the progression of HF and may improve long-term morbidity and mortality. The transition from chronic HF to ADHF involves perturbations in multiple intersecting processes including neurohormonal circuits, inflammatory mediators, cardiorenal interactions, and myocardial performance. Concurrently, derangements in comorbid illnesses such as coronary disease, atrial and ventricular arrhythmias, and hypertension also contribute to the pathophysiology of ADHF.3 Ultimately, these multiple pathways lead to an elevation in ventricular filling pressures and signs of vascular congestion, which, in concert with symptoms from impaired cardiac output, lead to the clinical constellation of ADHF. This pathophysiologic paradigm highlights multiple opportunities for detecting early changes in the processes that …

Effects of different annuloplasty rings on anterior mitral leaflet dimensions

To assess the effects of annuloplasty rings on anterior mitral leaflet dimensions. Sixteen radiopaque markers were sutured evenly spaced over the surface of the anterior mitral leaflet in 57 sheep. The following rings were implanted in a releasable fashion: size 28-mm Cosgrove-Edwards band (Edwards Lifesciences, Irvine, Calif) (n = 11), rigid saddle-shaped annuloplasty ring (St Jude Medical Inc, St Paul, Minn) (n = 12), Carpentier-Edwards Physio (Edwards Lifesciences) (n = 12), IMR-ETlogix (Edwards Lifesciences) (n = 10), and GeoForm (Edwards Lifesciences) (n = 12). Under acute open chest conditions, 4-dimensional marker coordinates were measured using biplane videofluoroscopy with the annuloplasty ring inserted and after annuloplasty ring release. Septal-lateral and commissure-commissure dimensions were calculated from opposing marker pairs on the septal-lateral and commissure-commissure aspect of the anterior mitral leaflet at end diastole and end systole. To assess changes in anterior mitral leaflet shape, a "planarity index" was assessed by calculating the root mean square values as distances of the 16 anterior mitral leaflet markers to a best fit anterior mitral leaflet plane at end systole. At end diastole, anterior mitral leaflet septal-lateral and commissure-commissure dimensions did not change with the Cosgrove ring compared with control, whereas the rigid saddle-shaped annuloplasty ring and Physio, IMR-ETlogix, and GeoForm rings reduced anterior mitral leaflet commissure-commissure but not septal-lateral anterior mitral leaflet dimensions. At end systole, the septal-lateral anterior mitral leaflet dimension was smaller with the IMR-ETlogix and GeoForm rings, but did not change with the Cosgrove ring, rigid saddle-shaped annuloplasty ring, and Physio ring. Anterior mitral leaflet shape was unchanged in all 5 groups. With no changes in anterior mitral leaflet planarity, the 4 complete, rigid rings (rigid saddle-shaped annuloplasty ring, Physio, IMR-ETlogix, and GeoForm) reduced the anterior mitral leaflet commissure-commissure dimension at end diastole. The IMR-ETlogix and GeoForm rings decreased the septal-lateral anterior mitral leaflet dimension at end systole, probably as the result of inherent disproportionate downsizing. These changes in anterior mitral leaflet geometry could perturb the stress patterns, which in theory may affect repair durability.

A novel running annuloplasty suture technique for robotically assisted mitral valve repair

FIGURE 1. Schematic diagram of running annuloplasty suture technique. A, Fir at the mid-portion of the annulus and the tail is tied to the first suture. C, Second s tied to the second suture. From the Department of Thoracic and Cardiovascular Surgery and Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio. Disclosures: Dr Mihaljevic is a consultant for Intuitive Surgical Inc (Sunnyvale, Calif), St Jude Medical Inc (St Paul, Minn), and Edwards Lifesciences (Irvine, Calif). Dr Gillinov is a consultant for Edwards Lifesciences and St Jude Medical, receives research support from St Jude Medical and Medtronic (Minneapolis, Minn), and has equity in Viacor (Wilmington, Mass). Received for publication Nov 24, 2009; accepted for publication Dec 7, 2009; available ahead of print March 2, 2010. Address for reprints: Tomislav Mihaljevic, MD, Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44125 (E-mail: mihaljt@ccf.org). J Thorac Cardiovasc Surg 2010;139:1343-4 0022-5223/$36.00 Copyright 2010 by The American Association for Thoracic Surgery doi:10.1016/j.jtcvs.2009.12.023

Evaluation of a new left atrial retractor for minimally invasive mitral valve surgery

FIGURE 1. The MitraXs (St Jude Medical Inc, Minneapolis, Minn) is a self-supporting atrial retractor. A, In deployed position with 1 overmoduled pivoting rivet that makes its conical shape self-expanding and auto-adjusting. B, In rolled and compressed position, with triangular tab protruding out of the cylinder, which makes introduction into the left atrium easy. CLINICAL SUMMARY The MitraXs retractor is a pattern-cut polymer sheet that once deployed and secured by a pivoting rivet generates a conical volume (Figure 1). The device is a self-expanding, auto-adjusting, single-use left atrial retractor that does not require a supporting arm. The retractor has 2 sizes (A and B) according to valve diameter and 2 lengths (regular or ‘‘ þ’’) according to atrium depth to accommodate anatomic variations. The introduction and deployment of the MitraXs device are key points. After the folding step, the MitraXs device is rolled and compressed from a conical shape to a cylinder with a reduced diameter creating a protruding triangular tab (Figure 1). By using a locking forceps, theMitraXs device is introduced via a minithoracotomy and an atriotomy, the tab with the rivet at the top loading the atrial septum first; then, with a clockwise rotation of a half turn, the device is progressively pushed into the left atrium in a screwing movement. When the MitraXs device is completely engaged in the left atrium, centered on the valve, with the rivet down in the posterior position, the forceps is released and the retractor deploys back into an optimal conical shape, working as an ‘‘expander’’ and maintaining the left atriumwide open in a symmetric manner. The effectiveness of the MitraXs device was evaluated in 62 patients who consecutively underwent MIMVS during a 20-month period at the Louis Pradel Hospital. There

Three-dimensional bipolar voltage map demonstrating electrical activity of a single muscle bundle along the cavotricuspid isthmus

Ablation of the cavotricupsid isthmus (CTI) for the prevention of atrial flutter has traditionally been guided anatomically (1). Recently, an atrial electrogram (EGM) voltage-guided approach was described (2,3). It has been hypothesized that muscle bundles in the CTI are predominantly responsible for conduction through this area, and targeted ablation of those muscle bundles is an efficient and effective means to achieve bidirectional conduction block across the CTI. The muscle bundles can be identified by the highest-amplitude local atrial bipolar EGM recorded along any given ‘line’ between the tricuspid annulus and the inferior vena cava. A voltage map of the CTI bipolar atrial EGM was generated with a 4 mm, steerable irrigated-tip ablation catheter (Cool Path; St Jude Medical Inc, USA) during CTI-dependent atrial flutter (cycle length 243 ms) using a three-dimensional mapping system (NavX; St Jude Medical Inc). Figure 1 shows a caudal left anterior oblique view of the three-dimensional bipolar voltage map. A discrete line of high voltages was seen, demonstrating electrical activity of a single muscle bundle along the CTI. Figure 1) Three-dimensional bipolar voltage map (caudal left anterior oblique veiw). A discrete line of high voltages (purple colour, arrows) is seen, demonstrating electrical activity of a single muscle bundle along the cavotricuspid isthmus. The voltages corresponding ... In voltage maps, the voltages corresponding to the colour codes are indicated on the colour bar. Voltages higher than 1.8 mV (set arbitrarily) are shown in purple. The lowest voltages are shown in red. In the present voltage map, the region of the His potential was indicated by red dots. A duodecapolar catheter was in the right atrium, the ablation catheter was in the inferior vena cava and a reference catheter was in the coronary sinus. Visualization of the high-voltage area of the CTI with endocardial voltage mapping supports the muscle bundle hypothesis and helps with the understanding of the voltage-guided ablation approach for CTI-dependent atrial flutter.

Abstract 4646: Visually-Guided Ablation of the Pulmonary Venous Antrum Using a Compliant Balloon Catheter

Introduction: During AF ablation, placing contiguous point ablations to electrically isolate the PVs can be technically challenging. While balloon ablation catheters (BACs) using various energy sources can facilitate this procedure, they are limited by the relatively distal nature of the level of isolation; the PV antra remain largely un-ablated. This report details the in vivo evaluation of a compliant BAC with 1) the capability for endoscopic real-time visualization of the target tissue, and 2) an adjustable short arc of light energy for ablation. Methods: In 3 normal pigs, transseptal access was achieved followed by placement of a deflectable sheath and the BAC (Cardiofocus Inc). Once in position, a 30° arc of laser energy (980 nm) was manipulated to create an isolating antral lesion set. PV isolation was confirmed using a circular mapping catheter. The level of isolation was also visualized by high-density electroanatomical mapping (NavX, St Jude Medical Inc). Results: The BAC was able to conform to the PV antra (Fig-A/B ); a 3D reconstruction of the BAC while in position is shown in Fig C . Circumferential endoscopic contact was observed for all 4 PVs targeted for ablation (3-RSPVs, 1-LSPV). Electrical PV isolation was achieved for all 4 PVs. The level of RSPV (arrow) isolation is seen on the voltage maps at baseline (Fig D ), post-partial ablation (Fig E ) and post-isolation (Fig F ); shown are PA views. There was no PV stenosis, thrombus formation or atrial perforation. Pathological examination confirmed the lesions to be both transmural and antral in location. Conclusions: The PV antra can be targeted for ablation using this visually-guided compliant balloon ablation system.

Acute rupture of both papillary muscles after aortic valve replacement for infective endocarditis

Acute rupture of both papillary muscles after aortic valve replacement for infective endocarditis

A prospective randomized comparison of the Medtronic Advantage Supra and St Jude Medical Regent mechanical heart valves in the aortic position: Is there an additional benefit of supra-annular valve positioning?

The aim of this prospective randomized trial was to evaluate the impact of complete supraannular positioning of mechanical aortic bileaflet valves. Between April of 2004 and November of 2006, 80 patients underwent aortic valve replacement with the complete supraannular Medtronic Advantage Supra (n = 40) (Medtronic Inc, Minneapolis, Minn) or the intra-supraannular St Jude Medical Regent (n = 40) prosthesis (St Jude Medical Inc, St Paul, Minn). Before randomization and valve sizing for both valve types, the aortic tissue annulus diameter was determined by Hegar dilator. Transthoracic echocardiography data were obtained early postoperatively and at 6 months, including stress echocardiography. By grouping the data on the basis of a patient's tissue annulus diameter, no significant difference of either valve was detected with regard to mean pressure gradient and effective orifice area index at rest. Effective orifice area index ranged from 0.95 +/- 0.32 cm(2)/m(2) to 1.27 +/- 0.33 cm(2)/m(2) in the Advantage Supra group and from 0.98 +/- 0.36 cm(2)/m(2) to 1.26 +/- 0.37 cm(2)/m(2) in the Regent group. During exercise, mean pressure gradients increased from 11.9 +/- 4.9 mm Hg to 19.1 +/- 7.2 mm Hg in the Advantage Supra group and from 9.6 +/- 4.0 to 16.4 mm Hg +/- 7.3 mm Hg in the Regent group. A marked left ventricular mass regression across all annulus sizes was noted in both groups (P < .001). Sizing for both valve types showed that in 26.3%, the completely supraannular valve design allows the implantation of a 1 size larger valve in label than the corresponding intra-supraannular valve. By grouping the data on the basis of a patient's tissue annulus diameter, no significant superiority of either prosthesis was detected with regard to left ventricular mass regression, effective orifice area index, and mean pressure gradient during rest and exercise. We conclude that there is no additional benefit of supraannular valve positioning.

Biofilm formation on pyrolytic carbon heart valves: Influence of surface free energy, roughness, and bacterial species

The aim of this study was to analyze the interaction of surface free energy and roughness characteristics of different pyrolytic carbon heart valves with three bacterial species on biofilm formation. Three pyrolytic carbon heart valves (St Jude Medical [St Jude Medical Inc, Minneapolis, Minn], Sulzer Carbomedics [CarboMedics Inc, Austin, Tex], and MedicalCV [Medical Incorporated, Inver Grove Heights, Minn]) were tested. Roughness was measured by interferential microscopy and surface free energy by contact angle technique. To obtain a biofilm, prostheses were inserted into a bioreactor with Staphylococcus aureus P209, Staphylococcus epidermidis RP62A, or Pseudomonas aeruginosa PAO1. Adhesion was quantified by counting sessile bacteria. Morphologic characteristics of biofilms were evaluated with scanning electron microscopy. Roughness analysis revealed significant differences between the MedicalCV (35.18 +/- 4.43 nm) valve and St Jude Medical (11.03 +/- 3.11 nm; P < .0001) and Sulzer Carbomedics (8.80 +/- 1.10 nm; P < .0001) valves. Analysis of surface free energy revealed a higher level for the MedicalCV valve (41.03 mJ x m(-2)) than for both the Sulzer Carbomedics (38.93 mJ x m(-2)) and St Jude Medical (31.51 mJ . m(-2)) models. These results showed a correlation between surface free energy and bacterial adhesion for S epidermidis and P aeruginosa species. Regardless of the support, we observed significant adhesion differences for the three bacterial species. S aureus was the most adherent species, S epidermidis was the least, and P aeruginosa was intermediate. Our results suggest that adhesion of S epidermidis and P aeruginosa are dependent on pyrolytic carbon surface free energy and roughness, although S aureus adhesion appears to be independent of these factors. Improvement of pyrolytic carbon physicochemical properties thus could lead to a reduction in valvular prosthetic infections.

A new mechanical connector for distal coronary artery anastomoses in coronary artery bypass grafting: A randomized, controlled study

A new mechanical anastomotic device was evaluated, aiming at its future use in minimally invasive techniques or limited access surgery in patients undergoing coronary artery bypass grafting. Between April and December 2002, a total of 60 patients scheduled for elective multivessel bypass grafting were randomly assigned. One vein graft-coronary artery anastomosis per patient was either performed with the St Jude Medical ATG coronary connector system (n = 30; St Jude Medical Inc, St Paul, Minn) or hand sewn (n = 30). Selective coronary angiography or coronary magnetic resonance imaging of the studied graft and vessel was included in the 6-month follow-up. Twenty-eight of the connectors were successfully implanted. Two patients were excluded from the study because of conversion to hand-sewn anastomoses. Six connector-made anastomoses were bleeding at the anastomotic site. At the time of follow-up (190 postoperative days), all control anastomoses and grafts were patent, whereas 26% of the connector anastomoses were occluded. One graft in each group was patent but with stenosis. The St Jude Medical ATG coronary connector system for distal anastomoses represents a new concept for sutureless anastomoses in cardiac surgery. This randomized, controlled study shows lower graft patency for anastomoses performed with the connector than for hand-sewn control anastomoses. It illustrates the importance of controlled studies when evaluating new technical equipment in medicine.

“Our complication rates are lower than theirs”: Statistical critique of heart valve comparisons

Objectives: From the widely differing complication rates published for every heart valve, is it possible to determine a true rate for each valve and to compare the rates of two different valves? We investigated this question for the two most popular bileaflet valves. Methods: Aortic valve data were abstracted from 14 St Jude Medical (St Jude Medical Inc, Minneapolis, Minn; 33,125 patient-y) and 11 Carbomedics (Sulzer Carbomedics Inc, Austin, Tex; 19,141 patient-y) series, and mitral valve data were abstracted from 11 St Jude Medical (21,553 patient-y) and 8 Carbomedics (8368 patient-y) series. Regression analysis was used to accommodate heterogeneity among rates with the same valve model, to estimate hazard ratios and 95% confidence intervals for the valve model effect, and to incorporate other series-level risk factors. Results: Most of the complication rates with both valve models exhibited significant heterogeneity. For thromboembolism and bleeding, the relative risks for valve model were not significantly different from unity. Valve thrombosis rates exhibited less heterogeneity: the Carbomedics valve had a lower rate in the aortic position (hazard ratio 0.2, 95% confidence interval 0.1-0.6) and a higher rate in the mitral position (hazard ratio 1.9, 95% confidence interval 1.0-3.8). Conclusions: Unlike simple weighted averages of valve complication rates, regression methods can incorporate heterogeneity related to center effects and allow for inclusion of other risk factors. Thromboembolism and bleeding rates were not significantly different with St Jude Medical and Carbomedics valves. Valve thrombosis appeared to differ between the two valves, but the absolute differences in rates were small. Because of the variability among rates with the same valve, statistical comparisons must be interpreted cautiously.J Thorac Cardiovasc Surg 2003;125:290-300

Microflow fields in the hinge region of the CarboMedics bileaflet mechanical heart valve design

Objective: The design of bileaflet mechanical heart valves includes some degree of leakage flow on valve closure for the reverse flow to wash the hinge and pivot region of the valve. It is believed that this reverse flow helps to prevent areas of stasis and inhibit microthrombus formation. However, the magnitude of this retrograde flow may also give rise to unacceptable levels of blood element damage and lead to platelet activation or hemolysis as a result of the increased flow velocities through the hinge region. The purpose of this study was to evaluate the hinge flow dynamics of a 23-mm CarboMedics bileaflet mechanical valve (Sulzer CarboMedics Inc, Austin, Tex) and then to compare the results with those of the St Jude Medical 23-mm Regent (St Jude Medical Inc, Minneapolis, Minn) and Medtronic Parallel (Medtronic, Inc, Minneapolis, Minn) valves studied earlier. This comparison allows new insight into the microflow fields within the hinge region of the CarboMedics bileaflet mechanical valve, which have not been previously assessed during its clinical history. Methods: Two-dimensional laser Doppler velocimetry was used to measure the velocity and turbulent shear stress fields in the hinge regions. To conduct these measurements, exact dimensional models of the bileaflet hinge regions were cast or machined from transparent plastic materials. The experiment was conducted in a pulsatile flow loop with measurements taken at different levels within the pivot and hinge regions. Results: In the 23-mm CarboMedics valve hinge, the phase-averaged forward velocity obtained at the flat level and levels of 190 μm and 390 μm above flat and 1 mm below flat were 0.54 m/s, 0.77 m/s, 0.3 m/s, and 1.0 m/s, respectively. Corresponding values of the peak phase-averaged leakage velocities were 3.17 m/s, 2.91 m/s, 2.52 m/s, and 0.5 m/s, respectively. Corresponding turbulent shear stresses were 5510 dyne/cm2, 5640 dyne/cm2, 4380 dyne/cm2, and 4810 dyne/cm2, respectively. Conclusions: The hinge flow dynamics of the CarboMedics bileaflet design lie somewhere in between those of the St Jude Medical and the Medtronic Parallel valve designs. The fluid dynamics of the investigated valve were found to be similar to those of the St Jude Medical valves, although with slightly higher leakage velocities and turbulent shear stresses. This discrepancy may be a result of the sharper corners associated with the hinge design of the CarboMedics valve. It could also be due to the incremental enlargement of the internal orifice area of the St Jude Medical Regent design.J Thorac Cardiovasc Surg 2002;124:561-74