In vivo fluid dynamics of the Ventura interatrial shunt device in patients with heart failure.

AIMS: Interatrial shunts are under evaluation as a treatment for heart failure (HF); however, their in vivo flow performance has not been quantitatively studied. We aimed to investigate the fluid dynamics properties of the 0.51 cm orifice diameter Ventura shunt and assess its lumen integrity with serial transesophageal echocardiography (TEE). METHODS AND RESULTS: Computational fluid dynamics (CFD) and bench flow tests were used to establish the flow-pressure relationship of the shunt. Open-label patients from the RELIEVE-HF trial underwent TEE at shunt implant and at 6 and 12 month follow-up. Shunt effective diameter (Deff) was derived from the vena contracta, and flow was determined by the continuity equation. CFD and bench studies independently validated that the shunt's discharge coefficient was 0.88 to 0.89. The device was successfully implanted in all 97 enrolled patients; mean age was 70 ± 11 years, 97% were NYHA class III, and 51% had LVEF ≤40%. Patency was confirmed in all instances, except for one stenotic shunt at 6 months. Deff remained unchanged from baseline at 12 months (0.47 ± 0.01 cm, P = 0.376), as did the trans-shunt mean pressure gradient (5.1 ± 3.9 mmHg, P = 0.316) and flow (1137 ± 463 mL/min, P = 0.384). TEE measured flow versus pressure closely correlated (R2 ≥ 0.98) with a fluid dynamics model. At 12 months, the pulmonary/systemic flow Qp/Qs ratio was 1.22 ± 0.12. CONCLUSIONS: When implanted in patients with advanced HF, this small interatrial shunt demonstrated predictable and durable patency and performance.

Interatrial shunt therapy in advanced heart failure: Outcomes from the open-label cohort of the RELIEVE-HF trial.

AIMS: Heart failure (HF) outcomes remain poor despite optimal guideline-directed medical therapy (GDMT). We assessed safety, effectiveness, and transthoracic echocardiographic (TTE) outcomes during the 12 months after Ventura shunt implantation in the RELIEVE-HF open-label roll-in cohort. METHODS AND RESULTS: Eligibility required symptomatic HF despite optimal GDMT with ≥1 HF hospitalization in the prior year or elevated natriuretic peptides. The safety endpoint was device-related major adverse cardiovascular or neurological events at 30 days, compared to a prespecified performance goal. Effectiveness evaluations included the Kansas City Cardiomyopathy Questionnaire (KCCQ) at baseline, 1, 3, 6, and 12 months and TTE at baseline and 12 months. Overall, 97 patients were enrolled and implanted at 64 sites. Average age was 70 ± 11 years, 97% were in New York Heart Association class III, and half had left ventricular ejection fraction (LVEF) ≤40%. The safety endpoint was achieved (event rate 0%, p < 0.001). KCCQ overall summary score was improved by 12-16 points at all follow-up timepoints (all p < 0.004), with similar outcomes in patients with reduced and preserved LVEF. At 12 months, left ventricular end-systolic and end-diastolic volumes were reduced (p = 0.020 and p = 0.038, respectively), LVEF improved (p = 0.009), right ventricular end-systolic and end-diastolic areas were reduced (p = 0.001 and p = 0.030, respectively), and right ventricular fractional area change (p < 0.001) and tricuspid annular plane systolic excursion (p < 0.001) improved. CONCLUSION: Interatrial shunting with the Ventura device was safe and resulted in favourable clinical effects in patients with HF, regardless of LVEF. Improvements of left and right ventricular structure and function were consistent with reverse myocardial remodelling. These results would support the potential of this shunt device as a treatment for HF.

Interatrial Shunting for Heart Failure: Early and Late Results From the First-in-Human Experience With the V-Wave System.

OBJECTIVES: This was a first-in-human study to assess the feasibility, safety, and exploratory efficacy of interatrial shunting for treating high-risk heart failure (HF) in patients with reduced and preserved ejection fraction. METHODS: A single-arm open-label study of patients with New York Heart Association functional class III or IV HF on optimal therapy was performed at 6 centers. The V-Wave shunt, an hourglass-shaped implant containing a 1-way bioprosthetic valve, was implanted by transseptal catheterization. Clinical, functional, echocardiographic, and hemodynamic evaluations were performed at baseline, 3 and 12 months, and annually (clinical follow-up) thereafter (median follow-up 28 months; interquartile range: 21 to 31 months). RESULTS: A total of 38 patients were enrolled (30 with HF with reduced ejection fraction and 8 with HF with preserved ejection fraction; mean age 66 ± 9 years; 97% and 3% in New York Heart Association functional classes III and IV, respectively), and the shunt device was successfully implanted in all cases without periprocedural mortality. The rate of major device- or procedure-related complications during the first 12 months was 2.6% (periprocedural cardiac tamponade in 1 patient). At 3- and 12-month follow-up, there were improvements in New York Heart Association functional class (classes I and II in 78% and 60% of patients, respectively), quality of life (improvements ≥5 points in 74% and 73% of patients, respectively), and 6-min walk distance (mean increases of 41 ± 63 m and 28 ± 83 m, respectively) (p < 0.02 for all, data available for 36 patients), without changes in objective measures of left- or right-sided function. All shunts were patent at 3 months, but 5 of 36 (14%) had occluded, and another 13 of 36 (36%) were stenotic at the valve by 12 months. Patients with widely patent shunts had lower long-term rates of death, left ventricular assist device placement or heart transplantation (p = 0.001), and HF hospitalization (p = 0.008), along with a reduction of pulmonary capillary wedge pressure (from 23.3 ± 5.4 mm Hg at baseline to 18.0 ± 4.0 mm Hg at 12 months; p = 0.011). CONCLUSIONS: Interatrial shunting with the V-Wave system was feasible and safe in patients with HF with reduced and preserved ejection fraction. Improvements in clinical and functional status were observed early and at 12 months despite attenuation of shunt patency in one-half of the patients. Patients with preserved shunt patency tended to maintain clinical benefit during longer term follow-up. Device modification that improves the durability of patency is likely worthwhile before confirmation of these findings in a randomized trial.

Unidirectional left-to-right interatrial shunting for treatment of patients with heart failure with reduced ejection fraction: a safety and proof-of-principle cohort study.

BACKGROUND: In patients with heart failure, interventions to reduce elevated left atrial pressure improve symptoms and reduce the risk of hospital admission. We aimed to assess the safety and potential efficacy of therapeutic left-to-right interatrial shunting in patients with heart failure with reduced ejection fraction. METHODS: We did this proof-of-principle cohort study at one centre in Canada. Patients (aged ≥18 years) with New York Heart Association (NYHA) class III chronic heart failure with reduced ejection fraction were enrolled under the Canadian special access programme. Shunt implants were done after transseptal catheterisation with transoesophageal echocardiographic guidance under general anaesthesia. Patients had clinical and echocardiography evaluations at baseline and months 1 and 3 after shunt implantation. FINDINGS: Between Oct 10, 2013, and March 27, 2015, we enrolled ten patients. The device was successfully implanted in all patients; no device-related or procedural adverse events occurred during follow-up. Transoesophageal echocardiography at 1 month showed that all shunts were patent, with no thrombosis or migration. From baseline to 3 month follow-up, we recorded improvements in NYHA classification (from class III to class II in seven [78%] of nine patients, from class III to class I in one [11%] patient, and no change in one [11%] patient; p=0·0004); quality of life, as assessed by the Duke Activity Status Index (from a mean score of 13 [SD 6·2] to 24·8 [12·9]; p=0·016) and the Kansas City Cardiomyopathy Questionnaire (from a mean score of 44·3 [SD 9·8] to 79·1 [13·0]; p=0·0001); and 6 min walk test distance (from a mean of 244 m [SD 112] to 318 m [134]; p=0·016). Pulmonary capillary wedge pressure was reduced from a mean of 23 mm Hg (SD 5) at baseline to 17 mm Hg (8) at 3 months (p=0·035), with no changes in right atrial pressure, pulmonary arterial pressure, or pulmonary resistance. No patient was admitted to hospital for worsening heart failure. One (10%) patient was admitted to hospital with gastrointestinal bleeding at month 1; one (10%) patient died after incessant ventricular tachycardia storm, which led to terminal heart failure 2 months post-procedure. INTERPRETATION: This first-in-man experience with an implanted left-to-right interatrial shunt demonstrates initial safety and early beneficial clinical and haemodynamic outcomes in patients with heart failure with reduced ejection fraction. Further large-scale randomised studies are warranted. FUNDING: V-Wave.

Rationale and Design of the Left Atrial Pressure Monitoring to Optimize Heart Failure Therapy Study (LAPTOP-HF).

BACKGROUND: Daily measurements of left atrial pressure (LAP) may be useful for guiding adjustments in medical therapy that prevent clinical decompensation in patients with severe heart failure (HF). STUDY DESIGN: LAPTOP-HF is a prospective, multicenter, randomized, controlled clinical trial in ambulatory patients with advanced heart failure in which the safety and clinical effectiveness of a physician-directed patient self-management therapeutic strategy based on LAP measured twice daily by means of an implantable sensor will be compared with a control group receiving optimal medical therapy. The trial will enroll up to 730 patients with New York Heart Association functional class III symptoms and either a hospitalization for HF during the previous 12 months or an elevated B-type natriuretic peptide level, regardless of ejection fraction, at up to 75 investigational centers. Randomization to the treatment group or control group will be at a 1:1 ratio in 3 strata based on the ejection fraction (EF > or ≤35%) and the presence of a de novo CRT device indication. SUMMARY: LAPTOP-HF will provide essential information about the role of implantable LAP monitoring in conjunction with a new HF treatment paradigm across the spectrum of HF patients.

Thoracic impedance measures tissue characteristics in the vicinity of the electrodes, not intervening lung water: implications for heart failure monitoring.

The rationale for intrathoracic impedance (Z) detection of worsening heart failure (HF) presupposes that changes in Z reflect changes in pulmonary congestion, but is confounded by poor specificity in clinical trials. We therefore tested the hypothesis that Z is primarily affected by tissue/water content in proximity to electrodes rather than by lung water distribution between electrodes through the use of a new computational model for deriving the near-field impedance contributions from the various electrodes. Six sheep were implanted with a left atrial pressure (LAP) monitor and a cardiac resynchronization therapy device which measured Z from six vectors comprising of five electrodes. The vector-based Z was modelled as the summation of the near-field impedances of the two electrodes forming the vector. During volume expansion an acute increase in LAP resulted in simultaneous reductions in the near-field impedances of the intra-cardiac electrodes, while the subcutaneous electrode showed several hours of lag (all p<0.001). In contrast, during the simulated formation of device-pocket edema (induced by fluid injection) the near-field impedance of the subcutaneous electrode had an instantaneous response, while the intra-cardiac electrodes had a minimal inconsistent response. This study suggests that the primary contribution to the vector based Z is from the tissue/water in proximity to the individual electrodes. This novel finding may help explain the limited utility of Z for detecting worsening HF.

Effects of AV delay and VV delay on left atrial pressure and waveform in ambulant heart failure patients: insights into CRT optimization.

BACKGROUND: We hypothesized that left atrial pressure (LAP) obtained by a permanent implantable sensor is sensitive to changes in cardiac resynchronization therapy (CRT) settings and could guide CRT optimization to improve the response rate. We investigated the effect of CRT optimization on LAP and its waveform parameters in ambulant heart failure (HF) patients. METHODS: CRT optimization was performed in eight ambulant HF patients, using echocardiography as reference. LAP waveform was acquired at each of eight atrioventricular (AV) intervals and five inter-ventricular (VV) intervals. Selected waveform parameters were also evaluated for their sensitivity to CRT changes and agreement with echocardiography-guided optimal settings. RESULTS: Optimal AV and VV intervals varied considerably between patients. All patients exhibited significant changes in waveform morphology with AV optimization. Optimal AV delay determined from echocardiography ranged between 140 ms and 225 ms. Mean LAP tended to be lower at optimal setting 14 ± 3 mmHg compared to shorter (<100 ms) or longer (>160 ms) AV settings (P = 0.16). There were clear trends to smaller peak a-wave (P = 0.11) and gentler positive a-slope (P = 0.15) and positive v-slope (P = 0.09) with longer AV delays. Mean LAP and negative v-wave slope correlated well with echo-guided optimal setting, r = 0.91 (P = 0.001) and 0.79 (P = 0.03), respectively. No significant effects on LAP or waveform were seen during VV optimization. CONCLUSIONS: LAP and its waveform changes considerably with AV optimization. There is good agreement between echo-guided optimal setting and LAP. LAP could provide an objective guide to CRT optimization. (Clinical Trial Registry information: URL: http://www.clinicaltrials.gov. Unique Identifier: NCT00632372).

Comparative pathology of an implantable left atrial pressure sensor.

A left atrial pressure (LAP) monitoring system was developed for guiding the management of patients with heart failure. The LAP sensor is implanted into the left atrium via transseptal catheterization and affixed to the interatrial septum by nitinol anchors. The long-term safety of permanent implantation of the LAP sensor in patients was evaluated based on the comparative pathology in animals. Tissue specimens of the LAP sensor from 7 patients, 49 canines, and 14 ovine were examined for thrombosis and tissue overgrowth. Implant duration ranged from 22 to 1,686 days. Gross examination showed minimal-to-moderate tissue overgrowth with no evidence of migration, erosion, or perforation. There was no excessive host-to-device reaction or active thrombogenesis in any of the subjects that followed the antithrombotic therapy protocol. Micro-computed tomography scanning confirmed the structural integrity of the device. Low vacuum scanning electron microscopy and histology showed neoendocardial tissue overgrowth with no inflammation or fibrin. The pathology of both animal models was found to closely approximate the pathology in humans and favorably supports the long-term safety of the device.

An implantable left atrial pressure sensor lead designed for percutaneous extraction using standard techniques.

BACKGROUND: An implantable left atrial pressure (LAP) monitoring system for guiding the management of patients with advanced heart failure has the potential to require extraction, particularly in the setting of infection. The LAP sensor lead was designed to be suitable for ease of percutaneous extraction using standard techniques for extracting pacemaker and defibrillator leads. The clinical experience, to date, with percutaneous extraction of the LAP sensor lead is presented. METHODS: A total of 82 patients underwent successful implantation of the LAP sensor lead using transseptal catheterization. Five patients of the 82 patients during a cumulative follow-up period of 267 patient-years (median of 2.9 years/patient) underwent percutaneous extraction using manual traction with a locking stylet and/or an excimer laser sheath to bore through adhesions. The distal fixation anchors of the LAP sensor lead are designed to fold forward during extraction so that the sensor module can easily separate from the interatrial septum. RESULTS: Percutaneous extraction of the LAP sensor lead was accomplished successfully in all five patients with no embolic events, vascular tears, perforations, or other complications requiring surgical intervention. Manual traction alone was sufficient to detach the LAP sensor lead from the interatrial septum in all cases. Use of the excimer laser sheath was needed in selected cases to bore through scar tissue within the venous insertion site, but not within the heart. CONCLUSIONS: The extraction of the LAP sensor lead was accomplished safely using standard techniques and equipment for percutaneously extracting pacemaker and defibrillator leads.

Serial Doppler echocardiography and tissue Doppler imaging in the detection of elevated directly measured left atrial pressure in ambulant subjects with chronic heart failure.

OBJECTIVES: This study sought to determine the accuracy of Doppler echocardiography and tissue Doppler imaging (TDI) measurements in detecting elevated left atrial pressure (LAP) in ambulant subjects with chronic heart failure using directly measured LAP as the reference. BACKGROUND: Echocardiographic indexes including the ratio of transmitral to annular early diastolic velocities (E/e') may identify raised invasively measured left ventricular filling pressures when tested in cross-sectional studies in some populations. The accuracy of these indexes when measured sequentially remains untested. We determined the accuracy of Doppler echocardiography and TDI measurements in detecting elevated directly measured LAP in ambulant subjects with stable chronic heart failure. METHODS: Fifteen patients with New York Heart Association functional class II to III heart failure and a permanently implanted direct LAP monitoring device underwent serial echocardiography. Simultaneous resting mean LAP, Doppler mitral inflow, mitral annular TDI, and pulmonary venous inflow velocities were obtained on each occasion. Receiver-operator characteristic curve analysis was used to compare the accuracy of the Doppler variables to detect an elevated device LAP ≥15 and ≥20 mm Hg. RESULTS: The patients (13 men, mean age: 71 years, mean left ventricular ejection fraction: 32 ± 12%) underwent 60 simultaneous echocardiographic studies and LAP measurements with a median of 4 (1 to 7) studies per patient. Mean LAP was 16.9 (range 5 to 39 mm Hg) at echocardiography (n = 60). E/e' had the greatest accuracy for detection of LAP ≥15 mm Hg with an area beneath the receiver-operator characteristic curve >0.9. In comparison, area under the curve for mitral E velocity and mitral E/A were 0.77 and 0.76, respectively (p < 0.008 vs. E/e' medial and average). CONCLUSIONS: Single and serial measurements of mitral inflow and mitral annular TDI velocities (E/e') can reliably detect raised directly measured LAP in ambulant subjects with compensated chronic heart failure. (Hemodynamically Guided Home Self-Therapy in Severe Heart Failure Patients [HOMEOSTASIS]; NCT00547729).

Direct left atrial pressure monitoring in severe heart failure: long-term sensor performance.

We report the stability, accuracy, and development history of a new left atrial pressure (LAP) sensing system in ambulatory heart failure (HF) patients. A total of 84 patients with advanced HF underwent percutaneous transseptal implantation of the pressure sensor. Quarterly noninvasive calibration by modified Valsalva maneuver was achieved in all patients, and 96.5% of calibration sessions were successful with a reproducibility of 1.2 mmHg. Absolute sensor drift was maximal after 3 months at 4.7 mmHg (95% CI, 3.2-6.2 mmHg) and remained stable through 48 months. LAP was highly correlated with simultaneous pulmonary wedge pressure at 3 and 12 months (r = 0.98, average difference of 0.8 ± 4.0 mmHg). Freedom from device failure was 95% (n = 37) at 2 years and 88% (n = 12) at 4 years. Causes of failure were identified and mitigated with 100% freedom from device failure and less severe anomalies in the last 41 consecutive patients (p = 0.005). Accurate and reliable LAP measurement using a chronic implanted monitoring system is safe and feasible in patients with advanced heart failure.

Monitoring of heart failure: comparison of left atrial pressure with intrathoracic impedance and natriuretic peptide measurements in an experimental model of ovine heart failure.

Monitoring of HF (heart failure) with intracardiac pressure, intrathoracic impedance and/or natriuretic peptide levels has been advocated. We aimed to investigate possible differences in the response patterns of each of these monitoring modalities during HF decompensation that may have an impact on the potential for early therapeutic intervention. Six sheep were implanted with a LAP (left atrial pressure) sensor and a CRT-D (cardiac resynchronization therapy defibrillator) capable of monitoring impedance along six lead configuration vectors. An estimate of ALAP (LAP from admittance) was determined by linear regression. HF was induced by rapid ventricular pacing at 180 and 220 bpm (beats/min) for a week each, followed by a third week with daily pacing suspensions for increasing durations (1-5 h). Incremental pacing induced progressively severe HF reflected in increases in LAP (5.9 ± 0.4 to 24.5 ± 1.6 mmHg) and plasma atrial (20 ± 3 to 197 ± 36 pmol/l) and B-type natriuretic peptide (3.7 ± 0.7 to 32.7 ± 5.4 pmol/l) (all P<0.001) levels. All impedance vectors decreased in proportion to HF severity (all P<0.001), with the LVring (left ventricular)-case vector correlating best with LAP (r2=0.63, P<0.001). Natriuretic peptides closely paralleled rapid acute changes in LAP during alterations in pacing (P<0.001), whereas impedance changes were delayed relative to LAP. ALAP exhibited good agreement with LAP. In summary, impedance measured with an LV lead correlates significantly with changes in LAP, but exhibits a delayed response to acute alterations. Natriuretic peptides respond rapidly to acute LAP changes. Direct LAP, impedance and natriuretic peptide measurements all show promise as early indicators of worsening HF. ALAP provides an estimate of LAP that may be clinically useful.

Physician-directed patient self-management of left atrial pressure in advanced chronic heart failure.

BACKGROUND: Previous studies suggest that management of ambulatory hemodynamics may improve outcomes in chronic heart failure. We conducted a prospective, observational, first-in-human study of a physician-directed patient self-management system targeting left atrial pressure. METHODS AND RESULTS: Forty patients with reduced or preserved left ventricular ejection fraction and a history of New York Heart Association class III or IV heart failure and acute decompensation were implanted with an investigational left atrial pressure monitor, and readings were acquired twice daily. For the first 3 months, patients and clinicians were blinded as to these readings, and treatment continued per usual clinical assessment. Thereafter, left atrial pressure and individualized therapy instructions guided by these pressures were disclosed to the patient. Event-free survival was determined over a median follow-up of 25 months (range 3 to 38 months). Survival without decompensation was 61% at 3 years, and events tended to be less frequent after the first 3 months (hazard ratio 0.16 [95% confidence interval 0.04 to 0.68], P=0.012). Mean daily left atrial pressure fell from 17.6 mm Hg (95% confidence interval 15.8 to 19.4 mm Hg) in the first 3 months to 14.8 mm Hg (95% confidence interval 13.0 to 16.6 mm Hg; P=0.003) during pressure-guided therapy. The frequency of elevated readings (>25 mm Hg) was reduced by 67% (P<0.001). There were improvements in New York Heart Association class (-0.7+/-0.8, P<0.001) and left ventricular ejection fraction (7+/-10%, P<0.001). Doses of angiotensin-converting enzyme/angiotensin-receptor blockers and beta-blockers were uptitrated by 37% (P<0.001) and 40% (P<0.001), respectively, whereas doses of loop diuretics fell by 27% (P=0.15). CONCLUSIONS: Physician-directed patient self-management of left atrial pressure has the potential to improve hemodynamics, symptoms, and outcomes in advanced heart failure. Clinical Trial Registration Information- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00547729.

Direct left atrial pressure monitoring in ambulatory heart failure patients: initial experience with a new permanent implantable device.

BACKGROUND: We describe the first human experience with a permanently implantable, direct left atrial pressure (LAP) monitoring system in ambulatory patients with chronic heart failure. METHODS AND RESULTS: Eight patients with established heart failure and at least 1 heart failure hospitalization or unplanned visit for parenteral therapy in the last year underwent device implantation under fluoroscopic guidance. All subjects received aspirin 150 mg and clopidogrel 75 mg daily. Subjects measured LAP twice daily and attended a clinic regularly for data upload and device calibration. Right heart catheterization was performed at the time of device implantation and at 12 weeks. The device was implanted in all subjects with no procedural complications. At the 12-week follow-up, 87% of device LAP measurements were within +/-5 mm Hg of simultaneous pulmonary capillary wedge pressure readings over a wide range of pressures (1.6 to 71 mm Hg). Net drift corrected by calibration was -0.2+/-1.9 mm Hg/mo. During short-term follow-up, there were no device-related complications or systemic emboli. There were no deaths, no unplanned heart failure clinic visits, and no admissions for heart failure. CONCLUSIONS: Ambulatory monitoring of direct LAP with a new implantable device was well tolerated, feasible, and accurate at a short-term follow-up. Further follow-up and investigation are warranted to evaluate the clinical utility of LAP monitoring in patients with heart failure.

Pimecrolimus and dual pimecrolimus-paclitaxel eluting stents decrease neointimal proliferation in a porcine model.

OBJECTIVES AND BACKGROUND: The purpose of this study was to determine the effectiveness and vascular response of a pimecrolimus drug eluting stent and a combination (pimecrolimus + paclitaxel) stent as compared with bare metal controls in the porcine coronary model. METHODS AND RESULTS: In the first phase of the study, cobalt chromium stents were loaded with an erodible polymer and either a slow release or a fast release formulation of pimecrolimus. Thirty stents (metal, n = 10; pimecrolimus slow, n = 10; pimecrolimus fast, n = 10) were implanted in the coronary arteries of 10 pigs. At 30 days, neointimal proliferation and inflammation were both significantly less in the pimecrolimus fast release group as compared with the bare metal controls. Endothelialization was complete and equal in all three groups of stents. In the second phase of the study, stents were loaded with an erodible polymer with alternating reservoirs of paclitaxel and pimecrolimus. Twenty stents (8 control stents and 12 dual stents) were implanted in the coronary arteries of seven pigs. At 30 days, neointimal proliferation was significantly less in the dual drug group as compared with the bare metal controls. Endothelialization was complete in both groups of stents, suggesting complete healing of the arteries. CONCLUSIONS: In a 30-day porcine stent model, pimecrolimus inhibits neointimal proliferation as compared with bare metal stents. Also, the proof of concept of a dual drug eluting stent was established showing both safety and efficacy.

Noninvasive calibration of cardiac pressure transducers in patients with heart failure: an aid to implantable hemodynamic monitoring and therapeutic guidance.

BACKGROUND: Implantable cardiac pressure monitors require assurance of calibration. This study evaluated if airway pressure responses during Valsalva maneuver (VM) can be used for calibrating intracardiac pressure transducers. METHODS AND RESULTS: Thirty-eight heart failure patients performed VMs while cardiac and airway pressures were recorded. Patients were designated as Lower (L) if baseline PCW was <20 mm Hg (n = 17); otherwise, they were categorized as Higher (H) (n = 21). VMs were repeated in 9 H patients after nitroglycerin. Procedural success was 92% and there were no complications. Differences between filling pressure and airway pressure (effective pressure) were eliminated during VM (RA(eff) = -0.9 +/- 1.3, RVED(eff) = 1.2 +/- 1.1, PCW(eff) = 2.1 +/- 2.8, and LVED(eff) = 0.9 +/- 1.6 mm Hg), and filling pressures were highly correlated with airway pressure r = 0.94. On average, group H had higher PCW(eff) and LVED(eff) than L patients by 1.8 and 2.5 mm Hg (P < or = .002), respectively, but after nitrates their responses were identical. CONCLUSION: The relationships between cardiac filling pressure and airway pressure during the Valsalva maneuver are sufficiently reliable to be considered as a new, noninvasive method for establishing the calibration of cardiac pressure sensors in patients with heart failure.

Comparison of coronary artery bypass surgery with percutaneous coronary intervention with drug-eluting stents for unprotected left main coronary artery disease.

OBJECTIVES: This study evaluated the clinical outcomes of consecutive, selected patients treated with coronary artery bypass graft (CABG) surgery or percutaneous coronary intervention (PCI) with drug-eluting stents (DES) for unprotected left main coronary artery (ULMCA) disease. BACKGROUND: Although recent data suggest that PCI with DES provides better clinical outcomes compared to bare-metal stenting for ULMCA disease, there is a paucity of data comparing PCI with DES to CABG. METHODS: Since April 2003, when DES first became available at our institution, 123 patients underwent CABG, and 50 patients underwent PCI with DES for ULMCA disease. RESULTS: High-risk patients (Parsonnet score >15) comprised 46% of the CABG group and 64% of the PCI group (p = 0.04). The 30-day major adverse cardiac and cerebrovascular event (MACCE) rate for CABG and PCI was 17% and 2% (p < 0.01), respectively. The mean follow-up was 6.7 +/- 6.2 months in the CABG group and 5.6 +/- 3.9 months in the PCI group (p = 0.26). The estimated MACCE-free survival at six months and one year was 83% and 75% in the CABG group versus 89% and 83% in the PCI group (p = 0.20). By multivariable Cox regression, Parsonnet score, diabetes, and CABG were independent predictors of MACCE. CONCLUSIONS: Despite a higher percentage of high-risk patients, PCI with DES for ULMCA disease was not associated with an increase in immediate or medium-term complications compared with CABG. Our data suggest that a randomized comparison between the two revascularization strategies for ULMCA may be warranted.

The effect of variable release kinetics on Paclitaxel efficacy from a drug eluting stent in a porcine model.

AIMS: Paclitaxel is a potent and effective inhibitor of neointimal proliferation after coronary stenting. The Conor stent loaded with Paclitaxel can be programmed with multi-parameter matrix of dose, temporal release profiles and release pathways. The aim of this study was to determine the most efficacious dose and release pattern of Paclitaxel in a porcine model and parallels the PISCES trial. METHODS: 32 farm pigs were implanted with Conor stents loaded with 10 or 30 microg of Paclitaxel with, 10 or 30 day and mural or bidirectional release patterns. Angiographic and histomorphometric analysis was -performed at 30 and 90 days. RESULTS: All doses of Paclitaxel were angiographically superior to control (P < 0.01). At 30 days, intimal thickness was similar between Pisces D4 (30 microg/10 days, bidirectional release), D5 (10 microg/30 day mural) and D6 (30 microg/30 day, mural) with D4 having the lowest intimal thickness (167+/-59 microm). There was a significant increase in the mural injury associated with D4 in comparison to all other doses (P < 0.00001). At 90 days D4 was significantly worse in comparison to Pisces D5 and D6; (P < 0.01) and Pisces D5 and D6 were similar to controls. CONCLUSIONS: 10 day release of Paclitaxel may be too short a period to inhibit neointimal proliferation after coronary stenting, or the rapid release of Paclitaxel may induce chemical injury causing secondary insult to the artery resulting in a rebound increase in intimal thickness at 90 days. These data parallel clinical findings in the PISCES trial.