Robert J. Brewer

Gastrointestinal bleeding with the HeartMate II left ventricular assist device.

BACKGROUND Continuous flow left ventricular assist devices (CF-LVADs) have yielded improved outcomes compared with pulsatile flow devices for patients on long-term support. However, significant rates of gastrointestinal bleeding (GIB) have been observed during CF-LVAD support. METHODS From March 2006 through March 2011, 86 patients with chronic heart failure underwent implantation of a CF-LVAD (HeartMate II; Thoratec Corp., Pleasanton, CA). Records were reviewed to determine the prevalence of post-implant GIB, location of the bleeding site and associated morbidity and mortality. Uni- and multivariate analyses were conducted to identify independent predictors of GIB. RESULTS GIB occurred in 19 patients (22.1%) with a duration of support that ranged from 5 to 456 days. Sources of GIB included small bowel and rectum in 6 patients each, large bowel in 2 patients and stomach in 1 patient. No definite source was identified in 4 patients. There were no deaths referable to GIB. Recurrent GIB occurred in 4 patients. History of a GIB prior to LVAD implant was the only variable significantly different between patients with and without post-implant GIB (21.1% vs 10.4%, p = 0.016), and was the only independent predictor of GIB (OR = 2.24, 95% CI 2.121 to 2.435, p = 0.004). CONCLUSIONS Gastrointestinal bleeding is a frequent source of morbidity for patients on HeartMate II LVAD support but does not significantly impact survival. As implantation of CF-LVADs with non-pulsatile flow gains popularity for both bridge-to-transplant and destination therapy, a better understanding of the pathophysiology of GIB in these patients will be needed for minimizing this complication.

Impact of continuous-flow left ventricular assist device support on right ventricular function

BACKGROUND Continuous-flow (CF) pumps have yielded improvements in short- and long-term survival and quality of life, and have reduced the number of left ventricular assist device (LVAD)-related complications. However, their ability to unload the right ventricle (RV) and improve RV function has not been as clearly defined. We evaluated the short- and mid-term effects of CF-LVADs on central venous pressure (CVP), pulmonary artery pressures (PAP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI), RV ejection fraction (RVEF), RV end-diastolic dimension (RVEDD), RV stroke work index (RVSWI), tricuspid annular plane systolic excursion (TAPSE) and severity of tricuspid regurgitation (TR). METHODS From March 2006 through June 2012, 130 patients with chronic heart failure underwent implantation of a CF-LVAD (122 HeartMate II and 8 HeartWare devices) as a bridge to transplant (n = 76) or as destination therapy (n = 54). Patients with pre-operative long-term LVADs (n = 4) and patients who underwent concomitant tricuspid valve repairs during their LVAD implant (n = 21) were excluded from the analysis. Echocardiograms and right heart catheterizations of the remaining 105 patients were reviewed pre-operatively and at 1 and 6 months post-LVAD implantation. RESULTS At 1 month post-LVAD implantation, CVP decreased from 12.4 ± 5.9 mm Hg to 8.7 ± 4.5 mm Hg (p < 0.001), systolic PAP decreased from 52.3 ± 14.1 mm Hg to 36.8 ± 11.3 mm Hg (p < 0.001), PCWP decreased from 23.0 ± 9.4 mm Hg to 12.9 ± 8.0 mm Hg (p < 0.001), CI index increased from 1.8 ± 0.5 liters/min m2 to 2.4 ± 0.5 liters/min m2 (p < 0.001), RVEF increased from 33.1 ± 4.9% to 40.4 ± 6.2% (p < 0.001), RVEDD decreased from 36 mm to 31 mm (p = 0.020), RVSWI improved from 408.6 ± 144.6 mm Hg ml m2 to 614.4 ± 196.2 mm Hg ml m2 (p < 0.001), and mean TAPSE increased from 1.1 ± 0.4 cm to 1.9 ± 0.4 cm (p = 0.004). Similarly, qualitative RV function on echocardiography improved from 57.1% moderately or severely reduced pre-operatively to 38.1% at 1 month (p = 0.008). Severity of TR decreased from 11.4% moderate or severe pre-operatively to 4.8% at 1 month (p < 0.001). These improvements were maintained at 6 months post-LVAD. CONCLUSIONS CF-LVAD support significantly decreased CVP and RVEDD, with concomitant improvement in RV function, as measured by increases in RVEF, RVSWI and TAPSE, as well as improvements in the qualitative echocardiographic appearance of RV contractility and a reduction in TR.

Non-cardiac surgery in patients on long-term left ventricular assist device support

BACKGROUND An increasing number of patients on left ventricular assist device (LVAD) support are requiring non-cardiac surgical (NCS) procedures. We reviewed our experience with the management of patients on continuous flow (CF) LVAD support undergoing NCS. METHODS From March 2006 through March 2011, 86 patients with chronic heart failure underwent implantation of a HeartMate II (Thoratec Corp, Pleasanton, CA) LVAD. Clinical records of these patients were reviewed to identify patients who underwent NCS while on LVAD support, with a focus on peri-operative death, bleeding, thrombosis, and device malfunction, as well as management of pre-operative anti-coagulation. RESULTS While on CF-LVAD support, 20 patients underwent 25 NCSs, comprising 13 major and 12 minor procedures. Operations were performed electively in 22 and as emergencies in 3. No peri-operative deaths, thromboembolic complications, or device malfunctions occurred. The incidence of bleeding requiring transfusion of packed red blood cells was 36.0%, including 25% of patients undergoing minor NCSs and 46.2% undergoing major NCSs (p = 0.004). All bleeding complications occurred in patients on both warfarin and aspirin pre-operatively. The only significant differences between patients who did and did not require transfusion were pre-operative warfarin use and significantly higher pre-operative international normalized ratio in the transfused group (1.9 ± 0.4 vs 1.4 ± 0.3; p = 0.008). CONCLUSIONS Non-cardiac operations can be performed safely in patients with CF-LVADs. It may possible to reduce peri-operative bleeding by lowering pre-operative anti-coagulation goals, especially before major surgery. However, additional analysis is required to determine if this can be performed safely.

Stroke while on long-term left ventricular assist device support: incidence, outcome, and predictors.

Development of stroke while on left ventricular assist device (LVAD) support can be a source of significant morbidity and mortality. From March 2006 through November 2011, one hundred patients with chronic heart failure underwent implantation of a HeartMate II (HM II) LVAD (Thoratec Corp.) as a bridge to transplant (BTT; n = 65) or destination therapy (DT; n = 35). Records were reviewed to determine the prevalence and type of postimplant stroke, anatomic cerebral location of strokes, and associated morbidity and mortality. Cox multivariate logistic regression analysis was conducted to identify independent predictors of postoperative stroke. Strokes occurred in 12 patients (12.0%): four embolic and eight hemorrhagic. Median duration of support at the time of stroke was 281.0 days for embolic strokes and 380.5 days for hemorrhagic strokes (p = 0.028). Stroke patients had a significantly higher incidence of diabetes (66.7% vs. 40.9%; p = 0.024), history of preimplant stroke (16.7% vs. 4.5%; p = 0.046), and aortic cross-clamping with cardioplegic arrest during their LVAD implant (50.0% vs. 20.2%; p = 0.034) compared with patients without postoperative strokes. Mean international normalized ratio (INR) at the time of stroke was subtherapeutic in all four patients with embolic strokes (mean: 1.5 ± 0.1 IU; range 1.3–1.6 IU) and supratherapeutic in four of eight patients with hemorrhagic strokes (mean: 3.2 ± 2.2 IU, range: 1.4–7.0 IU; p = 0.024). There was a 25.0% 30 day mortality after stroke. Diabetes (odds ratio [OR] 6.36; p = 0.029), aortic cross-clamping with cardioplegic arrest (OR 4.75; p = 0.025), duration of LVAD support (OR 1.00; p = 0.008), and INR (OR 4.42; p = 0.020) were independent predictors of stroke in multivariate analysis with a trend toward significance for history of stroke (OR 6.25; p = 0.075). Stroke represented an important source of morbidity and mortality for patients on HM II LVAD support. As long-term device therapy continues to gain popularity for both BTT and DT, a better understanding of the predictors of stroke, more strict control of postoperative anticoagulation, and the establishment of a risk stratification model may aid in minimizing its occurrence.

Reduction in driveline infection rates: Results from the HeartMate II Multicenter Driveline Silicone Skin Interface (SSI) Registry

BACKGROUND During left ventricular assist device implantation, a surgical tunneling technique to keep the entire driveline (DL) velour portion in the subcutaneous tunnel, resulting in a silicone-skin interface (SSI) at the exit site, has been adopted by many centers. To assess long-term freedom from DL infection associated with this technique, a multicenter SSI registry was initiated. It was hypothesized that the modified tunneling technique is associated with at least 50% reduction in DL infection at 1 year post-implant compared with the velour-to-skin method used in the HeartMate II (HMII) Destination Therapy (DT) trial. METHODS SSI is a retrospective and prospective registry of patients who have received the HMII device. Results are reported from the retrospective cohort, which consists of 200 patients who were implanted during the period 2009-2012 with the SSI tunneling method and on HMII support for at least 10 months at the time of enrollment. The prevalence and incidence of DL infection after left ventricular assist device implantation in the SSI retrospective cohort were determined and compared with a control group of 201 patients also on HMII support for at least 10 months from the HMII DT clinical trial who were implanted during the period 2007-2009 using the traditional method in which a small section of the velour portion of the DL was externalized. RESULTS The 1-year and 2-year prevalence rates of DL infection were 9% and 19% in the SSI patient group compared with 23% and 35% in the control group (hazard ratio 0.49, 95% confidence interval 0.33-0.73, p < 0.001). The event-per-patient year was 0.11 and 0.22 for the SSI and control groups, respectively (p < 0.001). Based on a multivariate analysis, age and DL exit side were the only independent variables associated with DL infection. Effects of management changes over the eras were not studied and could have contributed to the findings. CONCLUSIONS These results suggest that leaving the entire DL velour portion below the skin is associated with 50% reduction in DL infection compared with results from the HMII DT trial.

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.

Extremes of body mass index do not impact mid-term survival after continuous-flow left ventricular assist device implantation

BACKGROUND Extremes of body mass index (BMI) are often considered contraindications to use of a left ventricular assist device (LVAD), but data regarding outcomes across the spectrum of BMI are limited. We sought to assess the association of BMI with survival and major morbidity after continuous-flow (CF) LVAD implantation. METHODS Patients (n = 896) enrolled in the HeartMate II LVAD bridge-to-transplantation and destination therapy trials were divided into 4 BMI groups: underweight (<18.5 kg/m(2)); normal (18.5 kg/m(2) ≤ BMI < 30 kg/m(2)); obese (30 kg/m(2) ≤ BMI < 35 kg/m(2)); and extremely obese (≥35 kg/m(2)). The association of BMI with survival was tested using Kaplan-Meier analysis and proportional hazards regression. Major adverse events were compared using Poissons regression and chi-square tests. RESULTS At implantation, 48 (5%) patients were underweight, 596 (67%) normal weight, 164 (18%) obese and 88 (10%) extremely obese. BMI extremes were associated with differences in creatinine, albumin, age, central venous pressure and etiology. BMI was not associated with survival in the univariate analysis (p = 0.83) or in adjusted models (extremely obese: hazard ratio [HR] 1.29, p = 0.231; obese: HR 0.94, p = 0.723; underweight: HR 1.23, p = 0.452). Underweight patients were more likely to have bleeding events (p < 0.001), whereas extremely obese patients had higher rates of device-related infection (p = 0.041) and rehospitalization (p = 0.014). CONCLUSIONS Overall survival in patients receiving CF LVAD is similar across BMI categories. Carefully selected patients at both extremes of BMI have good mid-term survival after LVAD and should be considered for LVAD implantation relative to overall risk profile.

Factors determining post-operative readmissions after left ventricular assist device implantation

BACKGROUND In the current era of extensive healthcare reform, there has been a heightened focus on the frequency and cause for readmissions within 30 days of discharge given that readmissions are not reimbursed by most providers. The aim of our study was to determine the frequency, etiology and patterns of 30-day readmissions among recipients of continuous-flow left ventricular assist devices (LVADs) at our institution as well to determine whether there were any significant predictors of readmission. METHODS From March 2006 through June 2013, 150 patients underwent implantation of a continuous-flow LVAD at our institution. Patients were stratified into two groups based on their 30-day readmission status. A total of 12 patients died before discharge and were excluded from our analysis. Causes for 30-day readmissions and duration of hospital stay for the readmissions were recorded. Numerous pre-operative variables and post-operative complications were compared using 2-sided t-tests and chi-square tests between patients who were and were not readmitted within 30 days of their discharge after their LVAD implant. RESULTS The 30-day readmission rate was 26.1% (36 of 138), with approximately 70% of post-operative readmissions occurring within 10 days of the patients initial hospital discharge. Recurrent heart failure (12 of 36, 33.3%) and gastrointestinal bleeding (8 of 36, 22.2%) were the most common causes for 30-day readmission. The median length of stay (LOS) for readmission was 11.7 days. Thirty-day readmission did not affect short- or long-term survival. On univariate analysis, post-operative gastrointestinal bleeding (GIB) was a significant risk factor for 30-day readmissions (HR 1.4, 95% CI 0.19 to 0.99, p = 0.05), and overall length of stay was a significant factor in reducing 30-day readmission rates (HR 0.91, 95% CI 0.85 to 0.99, p = 0.02). CONCLUSIONS Our experience indicates that 30-day readmission rates after LVAD implantation remain relatively high, with most occurring within 10 days of discharge. Recurrent heart failure and GIB were the most common causes of post-operative rehospitalization. In addition, GIB during the index hospitalization was a significant predictor of 30-day readmission.

Video-Assisted Thorascopic Removal of Migratory Acupuncture Needle Causing Pneumothorax

We report the case of a 25-year-old African-American man presenting to the Henry Ford Hospital emergency department with acute dyspnea secondary to a pneumothorax resulting from a migratory acupuncture needle. The patient received acupuncture treatment approximately 5 years prior to this presentation for treatment of posttraumatic chronic right shoulder pain. Chest radiography revealed retained needles in his right shoulder girdle and a needle overlying the thoracic cage with an attendant pneumothorax. Catheter aspiration for simple pneumothorax provided immediate symptomatic relief. Video-assisted thoracoscopy was then used to remove the migratory acupuncture needle from the chest wall. The patient recovered without complication and was discharged to home.

Patients with low compared with high body mass index gain more weight after implantation of a continuous-flow left ventricular assist device

BACKGROUND Patterns of weight change after implantation of a continuous-flow left ventricular assist device (CF-LVAD) can affect transplant candidacy and may influence outcomes. We evaluated changes in weight over a 24-month period from a national LVAD clinical trial database. METHODS A retrospective analysis was performed of 896 patients enrolled into the HeartMate II Clinical trials for bridge-to-transplant and destination therapy from March 2005 to January 2009. The patients were divided into 4 groups: underweight (body mass index [BMI] <18.5 [kg/m(2)]); normal (BMI 18.5 to 29.9); obese (BMI 30 to 34.9); and extremely obese (BMI ≥ 35). Baseline BMI was compared with BMI at 6 months and 24 months after implant. BMI change >10% of baseline was considered clinically significant. RESULTS At 6 months, underweight and normal-weight patients had significant increases in BMI, with effects sustained up to 24 months (p < 0.01). Underweight patients gained weight most often, with 75% showing clinically meaningful weight gain at 24 months. Obese and extremely obese patients, in contrast, did not experience weight change over the same period. Pre-albumin levels improved from baseline to 6 months in all patients. CONCLUSIONS Underweight and normal-weight patients had an increase in BMI after LVAD implantation, and these changes persisted through 24 months. The BMIs of obese and extremely obese patients remained unchanged. Nutritional status improved in all groups.