Five-box thoracoscopic maze based on the Gemini-S bipolar ablation device to treat atrial fibrillation.

Thoracoscopic atrial fibrillation ablation seeks to replicate the electrophysiological effects of more invasive, open surgical procedures. The authors present a lesion concept that includes isolation of the pulmonary veins, the left atrial posterior wall, and the superior vena cava, respectively, lines to inhibit perimitral and periauricular flutter circuits, and left atrial appendage closure. All lesions are tested for bidirectional block.

Outcome of medical therapy, repeat intervention, and mitral valve surgery after failed MitraClip therapy.

OBJECTIVES: Optimal treatment for residual mitral regurgitation (MR) after MitraClip failure is not clearly defined. We report our clinical experience and discuss treatment options. METHODS: Between January 2013 and January 2018, 37 patients (75 ± 8.9 years, 46% male) were admitted for symptomatic MR (grade 3.1 ± 0.47) diagnosed after previous MitraClip therapy. Clinical outcome of these patients, who underwent medical therapy alone (n = 8, M-group), repeat MitraClip therapy (n = 8, reMC group), or mitral valve surgery (n = 21, S-group) for residual MR, were retrospectively analyzed. RESULTS: Thirty-day survival was 88% (M-group), 100% (reMC-group), and 76% (S-group). The rate of discharge to home was 88% in the reMC-group, better than 38% in the M-group (p = 0.051) and 19% in the S-group (p < 0.001). Perioperative non-survivors in the S-group had high surgical risk with median logistic EuroSCORE of 64.6% (interquartile range 57.4%-87.0%); all died from low cardiac output syndrome or multiple organ failure. The main MR pathologies resulted from leaflet tear and tethering in the M-group, tethering in the reMC-group, and degenerative valve and leaflet tear in the S-group. Kaplan-Meier analysis of overall survival at 1 year showed better outcome for patients in the reMC-group (50%, 95% CI 15.2-77.5%) and S-group (47.6%, 95% CI 25.7-66.7%), as compared to those in the M-group (12.5%, 95% CI 0.70-42.3%) (log-rank test p = 0.108 and p = 0.167, respectively). CONCLUSION: Medical therapy alone after failed MitraClip therapy resulted in poor 1-year prognosis. In patients without extremely high surgical risk, repeat MitraClip therapy, or surgical revision MIGHT BE CONSIDERED depending on valve pathology and cardiac comorbidities.

EuroSCORE-predicted mortality and surgical judgment for interventional aortic valve replacement.

BACKGROUND AND AIM OF THE STUDY: Transcatheter aortic valve implantation (TAVI) is used as an alternative to conventional surgery in high-risk patients. The EuroSCORE quantifies the risk, and patients are selected for this procedure if their predicted mortality is high. The study aim was to evaluate the risk discrimination and calibration of the EuroSCORE, as well as the surgical judgment that is used when selecting the aortic valve replacement (AVR) approach. METHODS: Between 2003 and 2006, a total of 2757 patients underwent isolated, open AVR. The EuroSCORE was compared to the observed in-hospital mortality. A survey among surgeons assessed the relevance of patient-specific factors towards the approach of TAVI versus open AVR. RESULTS: Survivors of AVR had a lower additive EuroSCORE than non-survivors (7.2 +/- 3.34 versus 12.0 +/- 3.34; p < 0.001). The EuroSCORE demonstrated reasonable risk stratification (c-statistic 0.843, p < 0.001). However, none of the 67 non-survivors was correctly predicted (Hosmer-Lemeshow test; p < 0.001), and most patients with a high EuroSCORE survived AVR. The actual mortality was 2.8% as compared to a EuroSCORE-predicted mortality of 12.5 +/- 14.2% (p < 0.001). This poor calibration was worse with higher EuroSCOREs (Cusum test; p < 0.001). Surgeons identified a porcelain aorta as the only factor that warranted TAVI. Most EuroSCORE variables had either no relevance for treatment selection, or prompted open AVR. CONCLUSION: Patient selection for TAVI cannot be based on the EuroSCORE, because it lacks discrimination and center-specific calibration. Thus, individual, surgical judgment that weighs institutional expertise for high-risk patients against a possible reduction of mortality by using interventional techniques, is recommended.

[Electromyostimulation (EMS) in cardiac patients. Will EMS training be helpful in secondary prevention?]. / Elektromyostimulation (EMS) bei kardiologischen Patienten. Wird das EMS-Training bedeutsam für die Sekundärprävention?

BACKGROUND: Current guidelines concerning the treatment of patients with chronic congestive heart failure (CHF) include ergospirometry-directed dynamic exercises on a daily basis. Several prospective, randomized trials have confirmed its positive influence on clinical symptoms and prognosis of the disease. Patients with stable coronary artery disease (CAD) can benefit from a 27% reduction of mortality, as shown in meta-analyses of several studies. By contrast, patients with CHF have traditionally been discouraged from physical activities, which may have had detrimental consequences. They became even less able to participate in daily activities that in turn hastened the disease-driven atrophies of skeletal muscles. On the other hand, well-adjusted endurance training at 50-70% of maximum oxygen uptake was shown to improve overall fitness. In a recent metaanalysis, the mortality of patients with CHF was reduced by 35% by sports, and the rate of hospitalizations dropped by 28%. It is a well-perceived clinical problem that successful treatment is not possible without intensive guidance and a close therapeutic relationship. Being left in their routine situation and circumstances, the majority of patients cannot cope with the day-to-day challenge of an independent, active lifestyle. Among the primary reasons not to sustain physical activity are mental, psychological or social barriers. PATIENTS AND METHODS: The authors have begun, in a cohort of patients with CHF, a prospective pilot study to investigate the impact of, and attitude to, electromyostimulation (EMS). Unique features of this treatment include its passive nature that remains independent of mental attitude. RESULTS: An up to 96% increase of peak oxygen uptake at the anaerobic threshold could be shown (pre- vs. posttraining phase, VO(2at) 19.39 [+/- 5.3] ml/kg vs. 24.25 [+/- 6.34] ml/kg). The diastolic blood pressure decreased significantly. A 14% gain in muscle volume was observed, while overall body weight remained unchanged. All patients kept up the training until the conclusion of the study and found their overall fitness to be considerably improved. CONCLUSION: The results may indicate the enormous potential of EMS for the treatment of patients within the cardiologic arena, especially those with CHF.

Left-thoracoscopic Convergent ablation for atrial fibrillation.

Epicardial Convergent ablation followed by endocardial touch-up and an additional ablation may be superior to catheter-based interventions in patients with persistent atrial fibrillation. We sought to extend the epicardial lesion set by changing the standard subxiphoid thoracotomy to a left-lateral, totally thoracoscopic approach. This tutorial depicts a closed-chest, beating-heart procedure, including ablation of the left atrial posterior wall, the left atrial dome, and the left pulmonary veins. The left atrial appendage is closed using an epicardial occlusion device.

Outcome comparison of mitral valve surgery and MitraClip therapy in patients with severely reduced left ventricular dysfunction.

AIMS: The aim of this study was to compare the outcomes of surgical mitral valve repair or replacement (sMVR) and percutaneous edge-to-edge repair using MitraClip (pMVR) in patients with severe left ventricular dysfunction affected by functional mitral regurgitation (FMR). METHODS AND RESULTS: We retrospectively identified 132 patients with left ventricular ejection fraction (LVEF) â‰¦ 30% submitted to sMVR (n = 47) or pMVR (n = 85) for FMR at our centre from January 2013 to December 2017. To adjust for baseline imbalances, we used a propensity score matching by age, logistic EuroSCORE, and left ventricular end-systolic volume. After being matched, MitraClip therapy showed lower perioperative mortality and rate of complications yet increased residual mitral regurgitation (MR) grade than did surgery (0.2 ± 0.50 in sMVR vs. 1.3 ± 0.88 in pMVR, P < 0.0001). According to stratified multivariate Cox model analysis, residual MR severity was an independent risk factor for cardiac death [hazard ratio (HR), 2.81; 95% confidence interval [CI], 1.44-5.48, P = 0.0025] and re-hospitalization for heart failure (HR, 3.07; 95% CI, 1.50-6.29, P = 0.0022) at 1 year follow-up. Stratified multivariable Cox regression analysis at 3 years identified pMVR as risk factor for cardiac death (HR, 0.19; 95% CI, 0.040-0.86, P = 0.031) and re-hospitalization for heart failure (HR, 0.28; 95% CI, 0.077-0.99, P = 0.048). CONCLUSIONS: In patients with FMR and LVEF ≤ 30%, MitraClip therapy resulted in lower perioperative complications and mortality than sMVR. However, surgically treated patients who survived the perioperative stage had less residual MR and experienced lower rates of re-hospitalization for heart failure at 1 year and lower cardiac mortality at 1 and 3 years of follow-up than did patients undergoing pMVR.

Surgical removal of occluder devices: complications and pitfalls.

Interventional closures of atrial septal defects (ASDs) and paravalvular leaks represent attractive treatment options to prevent surgical procedures. Nevertheless, a small number of complications or pitfalls remain after interventional closure of ASDs or paravalvular leaks that require surgical therapy. We report on 3 cases in which surgery was necessary after attempts to close a paravalvular leak. A mechanical valve prosthesis in the mitral position was explanted from a 73-year-old man because of increasing hemolysis and restriction of the motion of one leaflet by the occluder device. A 21-year-old woman with 3 previous surgeries for truncus arteriosus communis type 1 developed paravalvular leakage after replacements of the pulmonary and aortic valves. Although aortic insufficiency was reduced to grade I by placing 2 Amplatzer occluders, significant hemolysis developed. A 24-year-old woman had previously undergone 3 cardiac surgeries (commissurotomy at the age of 5 years for aortic stenosis, followed by aortic valve replacements at 13 and 14 years of age). The patient developed severe hemolysis after interventional closure. A redo aortic valve replacement was performed for the fourth time. As in the previous 2 cases, the surgery for this challenging case and the postoperative course went well. We also present 6 cases in which the occluder was explanted because of dislocation, thrombus formation, irritation of the aortic root, or systemic allergic reaction to the percutaneous occluder after initial closure of the ASD. The intra- and postoperative courses were uneventful in all cases. In summary, surgery for complications or pitfalls after interventional closure of paravalvular leaks or ASDs is challenging and carries a high risk in cases of paravalvular leaks. Nevertheless, the outcomes of the presented cases were uneventful. In the future, the development of a more suitable device technology may improve the results of interventional procedures, especially in cases of paravalvular leaks.

Patient self-monitoring of prosthetic heart valve function.

BACKGROUND AND AIM OF THE STUDY: Prosthetic heart valve dysfunction impacts on morbidity and quality of life. Although the diagnosis can be made by imaging studies, clinical symptoms commonly precede the diagnostic work-up. The ThromboCheck device analyzes the sound frequency spectra of valve motion, and alterations due to valve dysfunction are observed before overt clinical symptoms develop. The study aim was to determine if the ThromboCheck can be used to monitor the prosthetic valve function of patients at home. METHODS: Between 2003 and 2007, a total of 541 prosthetic heart valve recipients was prospectively enrolled into a double-blind, multi-center study. ThromboCheck devices were used to evaluate the sound frequency phenomena of valve motion. If the sound frequency spectra deviated from baseline, alarm signals were returned to the medical center via telephone, and these prompted evaluation by fluoroscopy and echocardiography. The clinical follow up included questionnaires at regular intervals. RESULTS: The cumulative observation period exceeded 748 patient-years, with a median follow up of 25.2 months per patient (range: 1 to 36 months). Almost all patients used the device at least two to three times per week to evaluate valve function, and the vast majority found it easy to operate. About 135,000 codes were returned to the study centers for further analysis; of these codes, 30 (0.0002%) were alarm signals. On 29 of the 30 occasions, prosthetic valve dysfunction was confirmed by fluoroscopy and echocardiography, yielding positive predictive values and specificities of 97% and 100%, respectively. There was no clinical event in the absence of a ThromboCheck alarm signal. Thrombolysis or increased warfarin-based anticoagulation quickly restored the initial sound frequency spectrum of the prosthetic valve in 16 patients. Another 13 patients were surgically revised; their prosthetic valves revealed significant thrombi upon replacement. By using the ThromboCheck device as part of a surveillance system, 79% of the patients felt safer with regards to prosthetic valve dysfunction. CONCLUSION: Analysis of sound frequency spectra by the ThromboCheck identified prosthetic heart valve dysfunction before clinical symptoms developed, and promoted early therapy. The restoration of valve function normalized the frequency spectra, which may be utilized to guide treatment. These results justify further efforts to introduce the analysis of sound phenomena into routine clinical care after prosthetic valve implantation.

Chronic hydrocephalus-induced changes in cerebral blood flow: mediation through cardiac effects.

Decreased cerebral blood flow (CBF) in hydrocephalus is believed to be related to increased intracranial pressure (ICP), vascular compression as the result of enlarged ventricles, or impaired metabolic activity. Little attention has been given to the relationship between cardiac function and systemic blood flow in chronic hydrocephalus (CH). Using an experimental model of chronic obstructive hydrocephalus developed in our laboratory, we investigated the relationship between the duration and severity of hydrocephalus and cardiac output (CO), CBF, myocardial tissue perfusion (MTP), and peripheral blood flow (PBF). Blood flow measures were obtained using the microsphere injection method under controlled hemodynamic conditions in experimental CH (n=23) and surgical control (n=8) canines at baseline and at 2, 4, 8, 12, and 16 weeks. Cardiac output measures were made using the Swan-Ganz thermodilution method. Intracranial compliance (ICC) via cerebrospinal fluid (CSF) bolus removal and infusion, and oxygen delivery in CSF and prefrontal cortex (PFC) were also investigated. We observed an initial surgical effect relating to 30% CO reduction and approximately 50% decrease in CBF, MTP, and PBF in both groups 2 weeks postoperatively, which recovered in control animals but continued to decline further in CH animals at 16 weeks. Cerebral blood flow, which was positively correlated with CO (P=0.028), showed no significant relationship with either CSF volume or pressure. Decreased CBF correlated with oxygen deprivation in PFC (P=0.006). Cardiac output was inversely related with ventriculomegaly (P=0.019), but did not correlate with ICP. Decreased CO corresponded to increased ICC, as measured by CSF infusion (P=0.04). Our results suggest that CH may have more of an influence on CO and CBF in the chronic stage than in the early condition, which was dominated by surgical effect. The cause of this late deterioration of cardiac function in hydrocephalus is uncertain, but may reflect cardiac regulation secondary to physiologic response or brain injury. The relationship between cardiac function and CBF should be considered in the pathophysiology and clinical treatment of CH.

Experimental study of new diagnostic system for coronary artery disease using coronary transit index.

OBJECTIVES: Noninvasive cardiac imaging techniques have had an increasing role in the diagnosis of coronary artery disease. However, these techniques are not widely available as a tool in the office setting. The purpose of this study was to provide an accurate assessment of coronary artery disease for screening purposes using Coronary Transit Index (CTI) assessment with small, high-resolution gamma cameras. METHODS: Total coronary blood flow was measured with ultrasonic flow probes placed around the left anterior descending coronary artery, left circumflex coronary artery, and right coronary artery in a total of 33 conditions in 5 healthy mongrel dogs. The coronary blood flow was reduced stepwise with vascular occluders placed around the coronary arteries. The procedure for obtaining CTI included 4 parts: 1) The animal was injected intravenously with a bolus of a radioactive tracer (2.5-5.0 mCi of (99m)Tc-DTPA); 2) Dedicated gamma sensors monitored the passage of the injected bolus; 3) Time-activity curves were measured at the left ventricle with and without its wall; 4) The ratio of the washout rates of the 2 curves determined the CTI. RESULTS: Coronary Transit Index was successfully obtained from the left ventricle. The coronary blood flows measured by flow probes were well correlated with the regional myocardial blood flow. The percentage of the baseline value of the total coronary blood flow had the highest correlation (R=0.807, p<0.0001) with the Coronary Transit Index. CONCLUSIONS: These data indicated that a new diagnostic system using CTI successfully identified reduced coronary blood flow.

Transmural distribution of myocardial blood perfusion and phasic coronary blood flow pattern in a canine model of acute ischemia.

BACKGROUND: Although several investigators have analyzed coronary artery blood flow under various conditions, almost all these studies have measured only some branches of the left anterior descending (LAD), left circumflex (LCX), or right coronary (RCA) artery. METHODS: In a canine model of acute ischemia (n = 5), we simultaneously assessed (a) regional myocardial blood perfusion using microspheres and (b) phasic coronary blood flow patterns as measured by three epicardial flow probes placed around the LAD, LCX, and RCA. RESULTS: The results from this study indicated that the LAD supplies blood to the epicardial (r = 0.687, p<0.0001), midwall (r = 0.556, p = 0.0021), and endocardial layers (r = 0.666, p = 0.0001) of the LAD area; the LCX supplies the midwall (r = 0.514, p = 0.0051) and endocardial layer (r = 0.621, p = 0.0004) of the LCX area, antero-lateral papillary muscle (r = 0.548, p = 0.0025), and postero-medial papillary muscle (r = 0.641, p = 0.0002), especially during the diastolic phase; and the RCA supplies the right ventricular apex (r=0.559, p=0.0020), left atrium (r = 0.618, p = 0.0005), right atrium (r = 0.471, p = 0.0114), and postero-medial papillary muscle (r = 0.486, p = 0.0088), especially during the systolic phase. CONCLUSIONS: These results are potentially relevant to understanding the physiology of myocardial blood perfusion and to improving treatment of acute myocardial ischemia and infarction.

Reduction of mitral regurgitation using the Coapsys device: a novel ex vivo method using excised recipients' hearts.

The purpose of this study was to evaluate the ex vivo effects of the Coapsys device upon functional mitral regurgitation (MR) in human hearts. We used seven excised hearts from patients who underwent cardiac transplantation. All patients had functional MR of grade 2 or greater associated with dilated (n = 3) or ischemic (n = 4) cardiomyopathy. After the aortic valve was removed, the left ventricle was pressurized from the aorta with saline at a constant pressure. The degree of MR was then subjectively graded from the opened left atrium (from 0 to 4). The last three studies included volumetric measurements of MR. By tightening the device, the mean MR grade was reduced from 3.3 +/- 0.8 to 1.1 +/- 0.4 (p = 0.0002). In the quantitative analysis, mean regurgitation volume was reduced from 1,108 +/- 1,134 ml/min to 236 +/- 89 ml/min (p = not significant). The mitral annular septal-lateral dimension decreased from 2.0 +/- 0.3 cm to 1.6 +/- 0.5 (p = 0.043). The Coapsys device reduced functional MR in the ex vivo study using excised dilated hearts.

The Coapsys device to treat functional mitral regurgitation: in vivo long-term canine study.

OBJECTIVE: We evaluated the capability of the Myocor Coapsys device (Myocor, Inc, Maple Grove, Minn) to reduce functional mitral regurgitation in a canine model of dilated cardiomyopathy. METHODS: Functional mitral regurgitation with heart failure was induced in 7 dogs by rapid ventricular pacing. The Coapsys device, which consists of anterior and posterior epicardial pads connected by a subvalvular chord, was then implanted. Heart failure was maintained by continued pacing for 8 weeks. Hemodynamic and echocardiographic measurements were performed at pre- and postsizing and after 8 weeks. The Coapsys subvalvular chord was cut to verify that maintenance of valve competency was due to the device. RESULTS: All implants were performed off-pump without atriotomy. Mitral regurgitation was reduced in all animals; mean mitral regurgitation grade was reduced from 2.9 +/- 0.7 to 0.7 +/- 0.8 (P =.00005) and was maintained at 0.8 +/- 0.8 after 8 weeks, without hemodynamic compromise or structural damage to the mitral valve. Mitral regurgitation returned to 3.6 +/- 0.8 (P =.102 versus presizing) after cutting the Coapsys subvalvular chord. CONCLUSION: The Coapsys device consistently and chronically reduced functional mitral regurgitation. This device is in clinical trials in the United States.

Neurohormonal response to left ventricular reconstruction surgery in ischemic cardiomyopathy.

OBJECTIVES: Activation of the neuroendocrine axis in congestive heart failure is of prognostic significance, and neurohumoral blocking therapy prolongs survival. The hypothesis that surgical reduction of left ventricular size and function decreases neuroendocrine activation is less established. We evaluated the neurohormonal response to left ventricular reconstruction surgery in ischemic cardiomyopathy. METHODS: Norepinephrine, plasma renin activity, and angiotensin II were measured in 10 patients before and 12 months after left ventricular reconstruction. In an additional 5 patients, brain natriuretric peptide was measured before and 3 months postoperatively. Three-dimensional cardiovascular imaging was used to assess ejection fraction and left ventricular end-diastolic volume index. RESULTS: Concurrent with improvements of New York Heart Association functional class (2.9 +/- 0.5 preoperatively vs 2.0 +/- 0.4 postoperatively, P <.001), ejection fraction (23.9% +/- 6.6% vs 36.2% +/- 6.2%, P <.01), and left ventricular end-diastolic volume index (140.8 +/- 33.8 mL/m(2) vs 90.6 +/- 18.3 mL/m(2), P <.01), considerable reductions were observed for median plasma profiles of norepinephrine (562.0 pg/mL vs 319.0 pg/mL, P <.05), plasma renin activity (5.75 microg/L/h vs 3.45 microg/L/h, P <.05), angiotensin II (41.0 ng/mL vs 23.0 ng/mL, P =.051), and brain natriuretric peptide (771.0 pg/mL vs 266.0 pg/mL, P <.05). The more plasma renin activity or angiotensin II decreased after left ventricular reconstruction, the higher was the increase in ejection fraction (R = -.745, P <.05 [plasma renin activity]; R = -.808, P <.05 [angiotensin II]). CONCLUSIONS: Surgical improvements of ejection fraction and left ventricular end-diastolic volume index by left ventricular reconstruction were accompanied by improvement of both the neuroendocrine activity and the functional status in patients with congestive heart failure. Whether this favorable neurohormonal response is predictive of an improved survival requires further evaluation.

Myosplint implant and shape-change procedure: intra- and peri-operative safety and feasibility.

BACKGROUND: In patients with dilated cardiomyopathy (DCM), the heart enlarges, leading to a corresponding increase in ventricular wall stress. To reduce the stress, transventricular tension members (Myosplint, Myocor, Inc.) were implanted to change the left ventricle (LV) effective radius and to reduce the LV wall stress by 20%. We conducted this study to evaluate the intra- and peri-operative safety and feasibility of LV-shape change therapy. METHODS: In 7 patients, all diagnosed with DCM, Myosplints were implanted. New York Heart Association class ranged from III-IV, and LV end-diastolic diameter ranged from 70 to 102 mm. Mitral valve regurgitation was classified as mild in 3 and moderate in 4 cases. Four patients underwent mitral valve annuloplasty. RESULTS: We observed no significant device-related complications, such as thromboembolism, bleeding, device instability, or vascular damage, at 90 days. Early indications in a small patient population demonstrate some improvements in clinical parameters. CONCLUSIONS: From this initial experience, one may conclude that placement of the Myosplint devices can be safely performed without early, significant adverse events. In patients with significant mitral valve incompetence, concomitant mitral valve repair is indicated to realize the full benefit of the procedure. This study also suggests that Myosplints can be safely implanted in combination with mitral valve repair. The long-term effect of each procedure on cardiac function and survival will require further evaluation.

Preclinical readiness testing of the Arrow International CorAide left ventricular assist system.

BACKGROUND: Left ventricular assist system technologies are currently being developed as effective alternatives to cardiac transplantation. In this study, in vivo testing of the Arrow International CorAide left ventricular assist system was conducted to determine its preclinical readiness based on demonstrated system performance and biocompatibility. METHODS: Arrow International CorAide blood pump assemblies were implanted in 7 calves for 1-month (n = 4) and 3-month (n = 3) durations without the use of chronic anticoagulation therapy. Hemodynamic performance, physiologic pump control, end-organ function, and device-related adverse events were evaluated during the studies and at autopsy. RESULTS: Hemodynamics were stable in all cases with a mean pump flow of 4.1 +/- 0.8 L/min and a mean arterial pressure of 101 +/- 4 mm Hg. In all calves, renal and hepatic function remained normal with no incidence of hemolysis, infection, bleeding, or embolism. The CorAide physiologic control algorithm demonstrated appropriate pump speed and flow adjustments in response to physiologically induced inputs, and the system's external electronic components demonstrated no hardware or software malfunction. All 7 cases were sacrificed electively. Autopsy revealed no sign of end-organ disease on gross and histologic examinations, and no device failure, malfunction, or mechanical wear of the pump blood-bearing surfaces was found. CONCLUSIONS: The Arrow CorAide left ventricular assist system demonstrated effective pump performance and good biocompatibility with no incidence of device-related adverse events. This system has completed its preclinical readiness testing and is approved for clinical trials in Europe in 2003.

Off-pump mitral valve repair using the Coapsys device: a pilot study in a pacing-induced mitral regurgitation model.

PURPOSE: The purpose of this study was to evaluate the ability of the Myocor Coapsys device to restore leaflet apposition and valve competency off-pump in a canine model of functional mitral regurgitation (MR). DESCRIPTION: The Coapsys device was surgically implanted in 10 dogs after MR induction by rapid ventricular pacing. The Coapsys consists of anterior and posterior epicardial pads connected by a subvalvular chord. The annular head of the posterior pad was positioned at the annular level to draw the posterior leaflet and annulus toward the anterior leaflet. Final device size was selected when MR was minimized or eliminated as assessed by color flow Doppler echocardiography. EVALUATION: All implants were placed off-pump without atriotomy, and mean MR grade was reduced from 2.9 +/- 0.7 to 0.6 +/- 0.7 (p < 0.001) acutely. No hemodynamic compromise was noted. CONCLUSIONS: The Coapsys device consistently and significantly reduced or eliminated functional MR acutely. Further study will be required to assess the chronic stability of the repair in this animal model.

Echocardiographic assessment of regional ventricular function after device-based change of left ventricular shape.

We assessed the effects of implantation of Myosplint (Myocor, Maple Grove, Minn), a device that changes left ventricular (LV) cross-sectional shape from circular to bilobar, on regional LV function. A total of 10 open-chest dogs with tachycardia-induced cardiomyopathy were studied before and after Myosplint implantation. LV cross-sectional epicardial echocardiography at the papillary muscle level was performed along with acquisition of hemodynamic data. LV normalized thickening, fractional thickening, end-diastolic thickness, and end-diastolic curvatures were calculated for 10 LV segments. Myosplint implantation did not affect LV hemodynamics, but decreased average end-diastolic curvature (P <.0001) and increased its segmental heterogeneity (P <.0001). There was no change in average fractional thickening, whereas normalized thickening increased (P =.05). In contrast, segmental heterogeneity of both normalized and fractional thickening increased (P =.02 and P =.01, respectively). Structural modeling confirmed that Myosplint implantation increases regional stress heterogeneity and curvature heterogeneity. LV cross-sectional shape markedly affects regional LV performance.

Changes in mitral annular and left ventricular dimensions and left ventricular pressure-volume relations after off-pump treatment of mitral regurgitation with the Coapsys device.

OBJECTIVE: The objective of this study was to evaluate the changes in mitral annular and left ventricular dimensions and left ventricular pressure-volume relations produced by the Myocor Coapsys device that has been developed to treat functional mitral regurgitation (MR) off-pump. METHODS: The Coapsys device, which consists of anterior and posterior epicardial pads connected by a sub-valvular chord, was implanted in seven dogs with functional MR resulting from pacing induced cardiomyopathy. The Coapsys device was then sized by drawing the posterior leaflet and annulus toward the anterior leaflet. During sizing, MR grade was assessed using color flow Doppler echocardiography. Final device size was selected when MR was eliminated or minimized. Following implantation, heart failure was maintained by continued pacing for a period of 8 weeks. Mitral annular and left ventricular dimensions and left ventricular pressure-volume relations were evaluated by two-dimensional echocardiography and a conductance catheter, respectively, at pre-sizing, post-sizing, and after 8 weeks. RESULTS: All implants were performed on beating hearts without cardiopulmonary bypass. Mean MR grade was reduced from 2.9+/-0.7 at pre-sizing to 0.7+/-0.8 at post-sizing (P<0.001), and was maintained at 0.8+/-0.8 after 8 weeks (P<0.01). The septal-lateral dimensions were significantly reduced at both mitral annular level [2.4+/-0.2 cm at pre-sizing, 1.5+/-0.3 cm at post-sizing (P<0.001) and 1.8+/-0.3 cm after 8 weeks (P<0.05)] and mid-papillary level [4.1+/-0.4 cm at pre-sizing, 2.4+/-0.2 cm at post-sizing (P<0.001) and 3.3+/-0.4 cm after 8 weeks (P<0.001)]. The end-systolic pressure-volume relation shifted leftward at post-sizing with a significantly steeper slope (P=0.03). There was a significant (P=0.03) leftward shift of the end-diastolic pressure-volume relation at post-sizing. After 8 weeks, these changes in pressure-volume relations tended to return to pre-sizing relations. CONCLUSIONS: The Coapsys device significantly reduced MR by treating both the mitral annular dilatation and the papillary muscle displacement. Despite these significant dimensional changes, the Coapsys device did not negatively affect the left ventricular pressure-volume relations.

In vivo performance and biocompatibility of the MagScrew ventricular assist device.

Currently available ventricular assist devices (VADs) have limitations in long-term durability and blood compatibility. We evaluated a prototype of a pulsatile MagScrew VAD for in vivo hemodynamic performance and biocompatibility. The device is composed of an actuator, blood pump housing, diaphragm, pusher plate, and bioprosthetic valves. Its protein-coated ("biolized") blood-contacting surface inhibits clot formation. Forces between moving parts of the actuator are transmitted magnetically, eliminating a primary source of friction and wear. The pump fills passively and is highly preload sensitive. The device was implanted into three calves for 90, 10, and 57 days, respectively. No anticoagulants were given postoperatively. The device functioned without technical problems during the entire course of each experiment, with mean device flow ranging between 5.4 and 9.0 L/min. Autopsy of the first two calves revealed no sign of embolization and clean blood-contacting surfaces of the devices. The third experiment was complicated by a prosthetic valve endocarditis with infectious embolization, and a few small depositions were found in the pump. In conclusion, the MagScrew VAD has demonstrated a high level of performance and biocompatibility in three calves studied for 10-90 days. Vigorous development is in progress to bring this device to preclinical readiness and thus provide surgeons with the VAD of choice for permanent implantation.