Hassan Nemeh

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.

Left ventricular reverse remodeling with a continuous flow left ventricular assist device measured by left ventricular end-diastolic dimensions and severity of mitral regurgitation.

Pulsatile flow left ventricular assist devices (LVADs) maximally unload the left ventricle (LV), leading to reverse remodeling of the myopathic LV that manifests as decreased LV end-diastolic dimension (LVEDD) and decreased severity of mitral regurgitation (MR). There is a paucity of data, however, regarding the ability of continuous flow (CF) pumps to adequately decompress the LV to induce similar reverse remodeling. We sought to evaluate the effects of CF-LVADs on LV reverse remodeling. From March 2006 through July 2011, one hundred patients with chronic heart failure underwent implantation of CF-LVAD (93 HeartMate II LVADs and seven HeartWare LVADs) as bridge-to-transplant (n = 68) and destination therapies (n = 32). Echocardiograms and right heart catheterizations were reviewed preoperatively and at 1 and 6 months post-LVAD implantation. Mean age was 52.1 ± 12.1 years; etiology of heart failure was ischemic cardiomyopathy in 34 patients and nonischemic dilated cardiomyopathy in 66 patients. Median LVAD support time was 378.3 days; 371.5 days for patients who received bridge-to-transplant therapy and 422.2 days for patients who underwent destination therapy. Left ventricular end-diastolic dimension significantly decreased at 1 month post-LVAD implantation from 71.6 ± 12.4 to 58.3 ± 13.8 mm (p < 0.001). Severity of MR also significantly decreased from 76.0% of patients having moderate or severe MR preoperatively to 8.0% with moderate or severe MR at 1 month post-LVAD (p < 0.001). These reductions were maintained at 6 months. These data demonstrate the ability of a CF-LVAD to significantly decompress the LV, leading to significant reductions in LVEDD and severity of MR. This reverse remodeling was apparent in the early postoperative period and was sustained at 6 months. Further studies are warranted to investigate whether this correlates with clinical LV recovery.

Lessons learned from 150 continuous-flow left ventricular assist devices: a single institutional 7 year experience.

Continuous-flow (CF) left ventricular assist devices (LVADs) have become the standard of care for patients with advanced heart failure refractory to optimal medical therapy. The goal of this study was to review our 7 year single institutional experience with CF LVADs. Mean age was 50.4 + 12.5 (17–69) years for bridge-to-transplantation (BTT) patients and 57.6 + 10.4 (31–81) years for destination therapy (DT) patients (p < 0.001). Overall, 38 patients (26%) were female and 58 (41%) were African American. Etiology of heart failure was ischemic in 54 patients (37%) and nonischemic in 93 patients (63%). Overall survival at 30 days, 6 months, 12 months, and 2 years was 93%, 89%, 84%, and 81%, respectively. Gastrointestinal bleeding (GIB) was the most common complication (24%), followed by stroke (18%), right ventricular (RV) failure (18%), ventilator-dependent respiratory failure (10%), reoperation for bleeding (10%), and driveline infection (9%). These data demonstrate excellent survival with low mortality for both BTT and DT patients on long-term LVAD support. However, for LVAD therapy to become the gold standard for long-term treatment of end-stage heart failure and a plausible alternative to heart transplantation, we need to continue to improve the incidence of frequent postoperative complications, such as RV failure, driveline infections, strokes, and GIB.

Sex-specific outcomes in patients receiving continuous-flow left ventricular devices as a bridge to transplantation or destination therapy.

Reports on sex-related outcomes in left ventricular assist device (LVAD) patients are conflicting. In addition, females have been underrepresented in most multicenter randomized controlled trials for mechanical circulatory support (MCS). The objective of our study was to analyze our experience implanting 130 continuous-flow LVADs and to determine the impact of sex on survival. We identified 130 patients who underwent implantation of a continuous-flow LVAD at our institution. Patients were stratified into two groups based on sex. Variables were compared using two-sided t-tests, &khgr;2 tests, Cox proportional hazards models, and log-rank tests to determine whether there was a difference between the two groups and if sex was a significant independent predictor of outcome. Of the 130 patients, 35 were females and 95 were males. Female patients had worse pre-LVAD cardiac output and cardiac index and were more likely to be on MCS at the time of implantation. Male patients had worse renal function. Survival was analogous for both cohorts with 30 day, 6 month, 1 year, and 2 year survivals of 97%, 90.8%, 90.8%, and 84.3%, respectively, for female patients versus 94.7%, 87.9%, 78.4%, and 72.8%, respectively, for male patients. The incidence of other LVAD-related complications was also similar in both groups. Gender did not predict postoperative mortality on univariate analysis. Contrary to most published reports, female and male LVAD patients have similar postoperative and midterm survival, length of hospital stay, readmission rates, and postoperative complications. It appears that females have gained more benefit from newer generation devices compared to males.

Short and long term outcomes of 200 patients supported by continuous-flow left ventricular assist devices

AIM To study the institutional experience over 8 years with 200 continuous-flow (CF) - left ventricular assist devices (LVAD). METHODS We evaluated our institutions LVAD database and analyzed all patients who received a CF LVAD as a bridge to transplant (BTT) or destination therapy from March 2006 until June 2014. We identified 200 patients, of which 179 were implanted with a HeartMate II device (Thoratec Corp., Pleasanton, CA) and 21 received a Heartware HVAD (HeartWare Inc., Framingham, MA). RESULTS The mean age of our LVAD recipients was 59.3 years (range 17-81), 76% (152/200) were males, and 49% were implanted for the indication of BTT. The survival rate for our LVAD patients at 30 d, 6 mo, 12 mo, 2 years, 3 years, and 4 years was 94%, 86%, 78%, 71%, 62% and 45% respectively. The mean duration of LVAD support was 581 d (range 2-2595 d). Gastrointestinal bleeding (was the most common adverse event (43/200, 21%), followed by right ventricular failure (38/200, 19%), stroke (31/200, 15%), re exploration for bleeding (31/200, 15%), ventilator dependent respiratory failure (19/200, 9%) and pneumonia (15/200, 7%). Our driveline infection rate was 7%. Pump thrombosis occurred in 6% of patients. Device exchanged was needed in 6% of patients. On multivariate analysis, preoperative liver dysfunction, ventilator dependent respiratory failure, tracheostomy and right ventricular failure requiring right ventricular assist device support were significant predictors of post LVAD survival. CONCLUSION Short and long term survival for patients on LVAD support are excellent, although outcomes still remain inferior compared to heart transplantation. The incidence of driveline infections, pump thrombosis and pump exchange have declined significantly in recent years.

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.

Mitral Valve Repair without Cardiopulmonary Bypass or Atriotomy Using the Coapsys Device: Device Design and Implantation Procedure in Canine Functional Mitral Regurgitation Model

BACKGROUND Myocor developed a unique system, the Coapsys annuloplasty system, to treat functional mitral regurgitation (MR) without cardiopulmonary bypass (CPB). This study was conducted to test the feasibility of the Coapsys implantation procedure in a canine functional MR model. METHODS Functional MR with heart failure was induced in 9 dogs by rapid ventricular pacing (230 beats/min for 30 +/- 4 days). The Coapsys device, which consists of anterior and posterior epicardial pads connected by a subvalvular chord, was then surgically implanted. Under epicardial echocardiographic guidance, we placed the Coapsys device across the left ventricular chamber using the delivery instrument and needle assembly. We sized the Coapsys device by drawing the posterior leaflet and annulus toward the anterior leaflet with the sizing instrument. Final device size was selected when MR was minimized or eliminated as assessed by 2-dimensional color Doppler echocardiography. RESULTS In all cases, we successfully implanted the Coapsys device without CPB or atriotomy. MR was reduced an average of 2 grades. No adverse events, such as hemodynamic compromise or structural valve damage, were noted. CONCLUSION Coapsys device implantation was feasible and safe on a beating canine heart. All accessory tools used for device implantation were found useful.

Outcomes of patients with right ventricular failure on milrinone after left ventricular assist device implantation.

Previous studies have grouped together both patients requiring right ventricular assist devices (RVADs) with patients requiring prolonged milrinone therapy after left ventricular assist device (LVAD) implantation. We retrospectively identified 149 patients receiving LVADs and 18 (12.1%) of which developed right ventricular (RV) failure. We then separated these patients into those requiring RVADs versus prolonged milrinone therapy. This included 10 patients who were treated with prolonged milrinone and eight patients who underwent RVAD placement. Overall, the RV failure group had worse survival compared with the non-RV failure cohort (p = 0.038). However, this was only for the subgroup of patients who required RVADs, who had a 1, 6, 12, and 24 month survival of 62.5%, 37.5%, 37.5%, and 37.5%, respectively, versus 96.8%, 92.1%, 86.7%, and 84.4% for patients without RV failure (p < 0.001). Patients treated with prolonged milrinone therapy for RV failure had similar survivals compared with patients without RV failure. In the RV failure group, age, preoperative renal failure, and previous cardiac surgery were predictors of the need for prolonged postoperative milrinone. As LVADs become a more widely used therapy for patients with refractory, end-stage heart failure, it will be important to reduce the incidence of RV failure, as it yields significant morbidity and increases cost.

Does Elective or Emergent Operative Status Influence Outcomes in Patients Undergoing Implantation of Left Ventricular Assist Devices

BACKGROUND Acuity models to predict survival after left ventricular assist device (LVAD) implantation do not include operative status as one of the calculated variables. The effect of elective versus emergent LVAD implantation on outcomes has not been examined. METHODS Patients were stratified into 2 groups based on operative status (elective versus emergent). Variables were compared to determine whether there were differences in outcomes between elective versus emergent LVAD recipients RESULTS Of the 130 patients, 59 underwent an elective procedure, whereas 71 had their LVAD implanted as an urgent/emergent operation. Patients in the urgent/emergent cohort had significantly worse preoperative hepatic and renal function and higher central venous pressures. Survival rates at 30 days, 6 months, 1 year, and 2 years were analogous for both cohorts. Patients in the emergent cohort had a higher incidence of postoperative right ventricular failure, with the requirement for short-term right ventricular support in 9.9% versus 1.7% (P = 0.054). The incidence of other LVAD-related complications, were similar in both groups. Emergency status did not predict postoperative mortality in univariate analysis. CONCLUSIONS Although patients who underwent emergent LVAD implantations had worse preoperative renal and liver function and a higher incidence of postoperative right ventricular failure, they exhibited similar midterm survival and a similar incidence of other postoperative complications.

Should left ventricular assist devices be implanted in patients seventy years of age and older: a comparative analysis.

BACKGROUND We evaluated outcomes in left ventricular assist device (LVAD) recipients aged seventy years and above and compared results to outcomes in LVAD recipients below seventy years of age. METHODS From March 2006 through June 2012, 130 patients underwent implantation of either a HeartMate II (HM II; Thoratec Corp., Pleasanton, CA) or HeartWare (HeartWare Inc., Framingham, MA) LVAD at our institution. Four patients underwent device exchanges and were excluded. Of the remaining 126 patients, 6 (4.7%) were ≥70 years of age. Patients in the age group ≥70 years were compared to the group of patients < 70 years for perioperative mortality, long-term survival and incidence of postoperative complications. RESULTS Mean age was 72.2 ± 2.3 (70-75) years for the older group and 52.8 ± 11.4 (18-69) years for the younger group (P < .001). There was no significant difference in the incidence of diabetes, hypertension, chronic renal insufficiency, dialysis, hepatic function, preoperative ventilation or previous cardiac surgery between the groups (P = NS). There was no significant difference in survival between the groups, with survival at 6 months, 1 year, and 2 years of 100%, 100% and 66.7% respectively for the older groups, versus 88.6%, 81.3% and 76.7% for the younger group (P = .634). There was no significant difference in postoperative bleeding requiring re-exploration, driveline infections, strokes, pneumonia, right ventricular failure, gastrointestinal bleeding or readmissions within thirty days (P = NS). CONCLUSIONS These data demonstrate similar short- and long-term results for the two groups of recipients of LVAD implantation. RESULTS support the use of long-term mechanical circulatory support in carefully selected elderly patients.