Background— Operative mortality after left ventricular assist device (LVAD) implantation is heavily influenced by patient selection and the technical difficulty of surgery. However, how we treat our patients and LVAD setting may affect the patient outcome beyond this period. We postulated that the presence of echocardiographic variables 1 month after surgery suggesting appropriate degree of LV unloading and an adequate forward flow would be important in determining clinical outcomes after the initial successful LVAD implantation. Methods and Results— We retrospectively analyzed various variables in echocardiographic examinations performed 30 days after LVAD implant in 76 consecutive patients receiving continuous flow device for their association with a compound end point (90-day mortality, readmission for heart failure, or New York Heart Association class III or higher at the end of the 90-day period). The echocardiographic associations examined included estimated LVAD flow, with and without native LV contribution, interventricular septal position, the status of aortic valve opening, an estimated left atrial pressure (ELAP), the mitral flow E-wave deceleration time, and the ratio of deceleration time to E-wave velocity (mitral deceleration index [MDI]). Four patients died during the 30- to 90-day period, 6 patients were readmitted for heart failure, and 25 patients were considered to have New York Heart Association class III or higher at the end of the 90-day period. Variables associated with adverse outcome included increased ELAP (odds ratio, 1.30 [1.16–1.48]; P <0.0001), MDI <2 ms/[cm/s] (odds ratio, 4.4 implantation [1.22–18]; P =0.02) and decreased tricuspid lateral annulus velocity (odds ratio, 0.70 implantation [0.48–0.95]; P =0.02). A leftward deviation of interventricular septum was associated with a worse outcome (odds ratio, 3.03 implantation [1.21–13.3]; P =0.01). Conclusions— Mortality and heart failure after LVAD surgery appear to be predominantly determined by echocardiographic evidence of inefficient unloading of the left ventricle and persistence of right ventricular dysfunction. Increased estimated LA pressure and short MDI are associated with worse mid term outcome. Leftward deviation of the septum is associated with worse outcome as well.
Left Ventricular Assist Device Therapy in Patients With Restrictive and Hypertrophic Cardiomyopathy
Background— Left ventricular assist device (LVAD) is being increasingly used in patients with end-stage dilated and ischemic cardiomyopathy. There have been no clinical trials addressing the use of LVAD therapy in patients with end-stage heart failure caused by restrictive (RCM) or hypertrophic cardiomyopathy (HCM). The purpose of this study was therefore to analyze the outcome of LVAD therapy in these patients. Methods and Results— Eighty-three patients received continuous axial flow LVAD (Heart mate II, Thoratec, Pleasanton, CA) from February 2007 to May 2010 at our institution. We analyzed the baseline characteristics and surgical and long-term impact of LVAD therapy in 8 patients with RCM or HCM and compared their outcomes with the 75 patients with dilated and ischemic cardiomyopathy. Compared with patients with ischemic or dilated cardiomyopathy, patients with RCM and HCM have significantly smaller left ventricular end-diastolic dimensions (52.5±6 mm versus 68.6±8 mm; P <0.0001) and increased thickness of septal (16 [12, 19] mm versus 10[8.5, 11] mm, P =0.0003) and higher left ventricular ejection fraction (21 [20, 36]% versus 17 [15, 22]%; P =0.0009). We found no difference in early mortality (12.5% versus 9.3%, P =0.57) or length of hospital stay (11 [8, 45] days versus 18.5 [12.2, 27.7] days; P =0.51) between the 2 groups. The right atrial pressure was higher (18 [15, 20] mm Hg versus 12 [9, 15] mm Hg, P =0.03), and pump flow was lower (4.3 [3.8, 4.5] L versus 5.2 [4.7, 5.5] L, P =0.001) after LVAD implantation in patients with RCM and HCM. Central venous catheter related infections were more common in patients with RCM and HCM (87.5% versus 44.5%, P =0.006). There was no difference in the total number of blood units transfused. Median (min, max) follow-up duration after LVAD implantation was 166 [1, 1044] days. The 1-year actuarial survival rate was not different between the 2 groups (87.5% [95% confidence interval, 52.9% to 97.8%] versus 73.2 [95% confidence interval, 60% to 85%]; P =0.77). Conclusions— Our preliminary data show that patients with end-stage heart failure caused by RCM or HCM may benefit from continuous axial flow LVAD therapy. This small study suggests that mortality is comparable with those patients who have dilated or ischemic cardiomyopathy, but right heart failure, prolonged inotropic use, and central venous catheter infections are more common in patients with RCM and HCM who were treated with LVAD. Because of the small numbers the differences should be interpreted cautiously, and prospective clinical trials would be required to recommend this therapy for these patients as bridge to transplantation or destination treatment.
Regulation of Circulating Progenitor Cells in Left Ventricular Dysfunction
Background— Reductions in numbers of circulating progenitor cells (CD34+ cell subsets) have been demonstrated in patients at risk for, or in the presence of, cardiovascular disease. The mediators of these reductions remain undefined. To determine whether neurohumoral factors might regulate circulating CD34+ cell subsets in vivo, we studied complementary canine models of left ventricular (LV) dysfunction. Methods and Results— A pacing model of severe LV dysfunction and a hypertensive renal wrap model in which dogs were randomized to receive deoxycorticosterone acetate (DOCA) were studied. Circulating CD34+ cell subsets including hematopoietic precursor cells (HPCs: CD34+/CD45 dim /VEGFR2−) and endothelial progenitor cells (EPCs: CD34+/CD45−/VEGFR2+) were quantified. Additionally, the effect of mineralocorticoid excess on circulating progenitor cells in normal dogs was studied. The majority of circulating CD34+ cells expressed CD45dimly and did not express VEGFR2, consistent with an HPC phenotype. HPCs were decreased in response to pacing, and this decrease correlated with plasma aldosterone levels (Spearman rank correlation=−0.67, P =0.03). In the hypertensive renal wrap model, administration of DOCA resulted in decreased HPCs. No changes were seen in EPCs in either model. Normal dogs treated with DOCA exhibited a decrease in HPCs in peripheral blood but not bone marrow associated with decreased telomerase activity. Conclusions— This is the first study to demonstrate that mineralocorticoid excess, either endogenous or exogenous, results in reduction in HPCs. These data suggest that mineralocorticoids may induce accelerated senescence of progenitor cells, leading to their reduced survival and decline in numbers.
Caveat Medicus! Pulmonary Hypertension in the Elderly: A Word of Caution
Abstract Heart failure with preserved ejection fraction (HFpEF) is a common but under-recognized cause of pulmonary hypertension (PH), particularly among the elderly. While elevated pulmonary artery pressures are clearly associated with increased mortality in HFpEF, it remains unknown whether or how pulmonary vascular disease in HFpEF should be treated. This case emphasizes the importance of maintaining a high index of suspicion for HFpEF in elderly patients presenting with PH and illustrates potential hazards associated with selective pulmonary vasodilation in this growing population.
Carotid Repair Using Autologous Adipose-Derived Endothelial Cells
Background and Purpose— Adipose tissue is an abundant source of endothelial cells as well as stem and progenitor cells which can develop an endothelial phenotype. It has been demonstrated that these cells have distinct angiogenic properties in vitro and in vivo. However, whether these cells have the capacity to directly improve large vessel form and function after vascular injury remains unknown. To define whether delivery of adipose-derived endothelial cells (ADECs) would improve healing of injured carotid arteries, a rabbit model of acute arterial injury was used. Methods— Autologous rabbit ADECs were generated using defined culture conditions. To test the ability of ADECs to enhance carotid artery repair, cells were delivered intraarterially after acute balloon injury. Additional delivery studies were performed after functional selection of cells before delivery. Results— After rabbit omental fat harvest and digestion, a proliferative, homogenous, and distinctly endothelial population of ADECs was identified. Direct delivery of autologous ADECs resulted in marked reendothelialization 48 hours after acute vascular injury as compared to saline controls (82.2±26.9% versus 4.2±3.0% P <0.001). Delivery of ADECs that were selected for their ability to take up acetylated LDL significantly improved vasoreactivity and decreased intimal formation after vascular injury. Conclusions— Taken together, these data suggest that ADECs represent an autologous source of proliferative endothelial cells, which demonstrate the capacity to rapidly improve reendothelialization, improve vascular reactivity, and decrease intimal formation in a carotid artery injury model.