Natural history and clinical effect of aortic valve regurgitation after left ventricular assist device implantation

ObjectivesAortic valve regurgitation reduces left ventricular assist device mechanical efficiency. Evidence has also suggested that left ventricular assist device implantation can induce or exacerbate aortic valve regurgitation. However, this has not been compared with aortic valve regurgitation progression in a nonsurgical end-stage heart failure population. Furthermore, its clinical effect is unclear. We sought to characterize the development and progression of aortic valve regurgitation in left ventricular assist device recipients and to identify its clinical effect.MethodsA review of all consecutive patients who received an intracorporeal left ventricular assist device at Duke University Medical Center from January 2004 to January 2011 was conducted. Cases of previous or concomitant aortic valve surgery were excluded. Data from the remaining implants (n = 184) and a control group of contemporaneous nonsurgical patients with end-stage heart failure (n = 132) were analyzed. Serial transthoracic echocardiography was used to characterize aortic valve regurgitation as a function of time.ResultsLeft ventricular assist device implantation was associated with worsening aortic valve regurgitation, defined as an increase in aortic valve regurgitation grade, relative to the nonsurgical patients with end-stage heart failure (P < .0001). The recipients of continuous flow left ventricular assist devices were more likely than recipients of pulsatile left ventricular assist devices to develop worsening aortic valve regurgitation (P = .0348). Moderate or severe aortic valve regurgitation developed in 21 left ventricular assist device recipients; this was unrelated to the type of device implanted (continuous vs pulsatile; P = .754) or aortic valve regurgitation grade before left ventricular assist device implantation (P = .42). Five patients developed severe aortic valve regurgitation; all of whom underwent aortic valve procedures.ConclusionsNative aortic valve regurgitation developed and/or progressed after left ventricular assist device implantation, with this effect being more pronounced in continuous flow left ventricular assist device recipients. However, the preoperative aortic valve regurgitation grade failed to correlate with the development of substantial aortic valve regurgitation after left ventricular assist device implantation. After left ventricular assist device implantation, aortic valve regurgitation had a small, but discernible, clinical effect, with some patients developing severe aortic valve regurgitation and requiring aortic valve procedures. These data have implications for the long-term management of left ventricular assist device recipients, in particular as the durability of implantable continuous flow left ventricular assist device therapy improves

Reproducibility of left atrial ablation with high-intensity focused ultrasound energy in a calf model

ObjectiveAchieving transmural tissue ablation might be necessary for successful treatment of atrial fibrillation. The purpose of this study was to evaluate the reproducibility of transmural left atrial ablation using a high-intensity focused ultrasound energy system in a calf model.MethodsNine heparinized bovines underwent a beating-heart left atrial ablation with a single application of the high-intensity focused ultrasound device. All animals were acutely killed, and the left atrium was fixed in formalin. Protocolized histological sections (5 μm) were obtained throughout each lesion and prepared with Masson trichrome and hematoxylin and eosin staining. Measurements were performed on a total of 359 slides from the 9 lesions. In addition, fresh left atrial tissues from 18 unused human donor hearts that did not meet the criteria for cardiac transplantation were measured at the site where the high-intensity focused ultrasound device is normally applied.ResultsCalf left atrial thickness ranged between 2.5 and 20.1 mm, with a mean of 9.10 mm. High-intensity focused ultrasound ablation consistently produced a 100% transmural lesion in left atrial thickness up to 6 mm. In addition, a transmural lesion was observed in 91% of tissues that were up to 10 mm thick and in 85% that were up to 15 mm thick. Human left atrial thickness ranged between 1.2 to 6 mm, with a mean of 3.7 mm.ConclusionsCalf left atrial thickness in this study was greater than human left atrial thickness. Human left atrial thickness is generally less than 6 mm, and in this range high-intensity focused ultrasound ablation achieved 100% transmurality. These histological results might correlate with a high success rate of atrial fibrillation ablation by using the high-intensity focused ultrasound system

Twenty-five-year outcomes after multiple internal thoracic artery bypass

ObjectiveCoronary artery bypass grafting with multiple internal thoracic artery grafts is currently controversial. This study assessed single institutional outcomes with multiple internal thoracic artery grafting for guidance with future clinical decisions.MethodsIn 19,482 patients undergoing multivessel coronary artery bypass grafting (1984-2009), baseline characteristics were recorded in a prospective databank, and follow-up was obtained by questionnaires, phone contact, or National Death Index. Outcomes examined were subsequent myocardial infarction, percutaneous coronary intervention, reoperative coronary artery bypass grafting, all-cause death, and a composite of the 4. Three groups were defined: (1) no internal thoracic artery graft (1874/19,482 or 9%); (2) single internal thoracic artery grafts and adjunctive venous conduits (single internal thoracic artery; 16,881/19,482 or 87%); and (3) multiple internal thoracic artery grafts (728/19,482 or 4%). Multivariable Cox modeling adjusted for differences in baseline characteristics, and comparisons were performed using area under the curve analysis.ResultsDifferences in baseline characteristics for the no internal thoracic artery graft, single internal thoracic artery, and multiple internal thoracic artery groups were as follows: median age 66, 64, and 59 years, respectively; congestive heart failure 22%, 18%, and 13%, respectively; ejection fraction 0.50, 0.52, and 0.51, respectively; reoperation 10%, 3%, and 7%, respectively; diabetes 27%, 30%, and 15%, respectively; and female gender 33%, 28%, and 20%, respectively. No differences existed in the median number of diseased vessels (3, 3, and 3, respectively) or number of grafts per patient (3, 3, and 3, respectively). Composite outcome improved with increasing internal thoracic artery grafts, whether assessing unadjusted or risk-adjusted data. Compared with no internal thoracic artery graft, the adjusted hazard ratio was 0.79 (confidence interval, 0.74-0.83) for single internal thoracic artery grafting and 0.70 (confidence interval, 0.62-0.80) for multiple internal thoracic artery grafting (both P < .001), reducing risk by 21% and 30%, respectively.ConclusionsThis study confirms improved patient outcomes with multiple internal thoracic artery grafting, achieving half again as much benefit as single internal thoracic artery grafting alone. The data suggest that increasing application of multiple internal thoracic artery grafting should be encouraged to mitigate the inherent risks and costs of long-term cardiac events

Outcomes After Implantable Left Ventricular Assist Device Replacement Procedures

As the duration of support increases for patients with continuous flow left ventricular assist devices (LVADs), device replacement may still be necessary for a variety of indications. Outcomes after replacement LVAD surgeries have not been extensively described, and whether these patients experience outcomes similar to primary LVAD implant patients remains unclear. From 2003 to 2012, 342 consecutive implantable LVAD procedures took place at a single institution, of which 201 were considered destination therapy. Within this larger group, 30 patients underwent 35 replacement procedures. The three major indications for replacement LVAD procedures were mechanical/electrical failure (57%), hemolysis/thrombosis (29%), and infection (14%). Propensity matching using preoperative characteristics was used to generate a primary implant control group to determine the impact of the replacement status on outcomes. Thirty-day and 1-year survival after LVAD replacement was 90% and 48%, respectively. Survival outcomes were worse for patients undergoing device replacement compared with the matched primary cohort (p = 0.03). The need for transfusion and the incidence of postoperative right ventricular and renal dysfunction were similar between the two groups, as was length of hospitalization. There was no difference between the rates of postoperative infection or stroke. Emergent replacement procedures had a higher mortality than those done nonemergently. Given these findings, earlier timing for replacement, temporary stabilization with an extracorporeal device, and use of a nonsternotomy surgical approach should be investigated as strategies to improve outcomes

Early Experience with a Novel Cannulation Strategy for Left Ventricular Decompression during Nonpostcardiotomy Venoarterial ECMO

Advances in technology for the delivery of venoarterial extracorporeal membrane oxygenation (VA-ECMO) have allowed for its expanded utilization in the treatment of patients with advanced cardiogenic shock, particularly through the use of peripheral cannulation strategies. However, peripheral VA-ECMO continues to be hampered by several major limitations including inadequate decompression of the left ventricle, lower limb ischemia, and the inability to mobilize patients. Here, we present a case series of three patients who were treated with a hybrid peripheral-central cannulation strategy accompanied by direct decompression of the left ventricle through a right anterior mini-thoracotomy. This novel approach ameliorates several of the current limitations to peripheral VA-ECMO therapy and thereby holds potential for improving outcomes in VA-ECMO patients

Heart Transplantation Survival and the Use of Traumatically Brain-Injured Donors: UNOS Registry Propensity-Matched Analysis

Background-The transplantation of hearts from traumatically brain-injured (TBI) donors has been associated with inferior long-term survival in single-center analyses. However, in a more recent analysis, death caused by cerebrovascular accident was associated with worse posttransplant survival in recipients. The purpose of this study was to explore the outcomes of heart transplantation in recipients receiving donor hearts from TBI and non-TBI donors in a large national registry. Methods and Results-We performed a retrospective cohort analysis of the UNOS (United Network of Organ Sharing) Registry Organ Procurement and Transplantation Network between 2006 and 2018 for adult candidates wait-listed for isolated heart transplantation. Recipients were stratified into 2 groups, TBI and non-TBI donors. Propensity score matching was performed. Kaplan-Meier analysis was used to estimate survival posttransplant. A total of 24 894 candidates met inclusion criteria. TBI was the leading cause of death in the donor population. Recipients of TBI donor hearts (N=13 07) were younger (median age, 55 versus 57 years; P<0.001) and less likely women (21.6% versus 29.8%; P<0.001). At 10 years, the TBI group had better long-term survival compared with the non-TBI group (62.8% versus 59.9%; P<0.001). After propensity group matching, the 10-year survival was similar between groups. Conclusions-In the largest analysis of heart transplants and their survival, according to the type of donor injury (TBI versus non-TBI), we found similar survival in heart transplant recipients. Future studies should address specific subpopulations (eg, hemorrhagic stroke) in the non-TBI group to address concerns about reduced posttransplant survival.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Heparin-induced thrombocytopenia in left ventricular assist device bridge-to-transplant patients

The presence of heparin-induced thrombocytopenia (HIT) increases the risk for thromboembolic events in ventricular assist device (VAD) patients undergoing transplantation. However, cardiopulmonary bypass with alternative anticoagulants is often complicated by bleeding. Owing to this concern, we compared outcomes of HIT-positive versus control bridge-to-transplantation VAD patients; both groups were reexposed to heparin for cardiopulmonary bypass during transplant. From February 2000 to January 2006, data were reviewed on 92 consecutive adult patients who underwent VAD placement as a bridge to transplantation. Patients in whom thrombocytopenia developed after heparin exposure were tested for HIT with an enzyme-linked immunosorbent assay for antiheparin/platelet factor-4 (HPF4) antibody (GTI Diagnostics, Waukesha, Wisconsin). During VAD support, heparin was avoided in HIT-positive patients, but all patients were reexposed to heparin during transplantation. Comparisons between HIT-positive and control patients for survival and freedom from thromboembolic events were determined using the Kaplan-Meier method and log-rank test. Continuous and categorical variables were compared using the Wilcoxon rank-sum and Student t test. Twenty-four of the 92 patients (26.1%) were determined to be HIT positive by enzyme-linked immunosorbent assay. Survival to transplant was not different between the two groups. When compared with control patients, HIT-positive patients who were reexposed to heparin had a greater decrease in platelet counts immediately after transplant (postoperative days 1 to 4, p < 0.05). Despite this transient thrombocytopenia, there was no difference in posttransplant mortality or thromboembolism. Heparin-induced thrombocytopenia-positive VAD patients did not experience increased thromboembolism or mortality after heparin reexposure. In light of the risks of using heparin alternatives, heparin reexposure is a safe management strategy for HIT-positive VAD patients

Elevated Cardiac Troponin I in Preservation Solution Is Associated With Primary Graft Dysfunction

Although primary graft dysfunction (PGD) is a leading cause of mortality and morbidity early post-heart transplant, relatively little is known regarding mechanisms involved in PGD development. We examined the relationship between cardiac troponin I (cTnI) concentrations in the preservation solution from 43 heart transplant procedures and the development of PGD. Donor hearts were flushed with cold preservation solution (University of Wisconsin [UW] or Custodiol) and stored in the same solution. cTnI concentrations were measured utilizing the i-STAT System and normalized to left ventricular mass. Recipient medical records were reviewed to determine PGD according to the 2014 ISHLT consensus conference. Nineteen patients developed PGD following cardiac transplantation. For both UW and Custodiol, normalized cTnI levels were significantly increased (P = .031 and .034, respectively) for those cases that developed PGD versus no PGD. cTnI levels correlated with duration of ischemic time in the UW group, but not for the Custodiol group. Donor age and donor cTnI (obtained prior to organ procurement) did not correlate with preservation cTnI levels in either UW or Custodiol. Increased preservation solution cTnI is associated with the development of PGD suggesting preservation injury may be a dominant mechanism for the development of PGD