Understanding Longitudinal Changes in Pulmonary Vascular Resistance After Left Ventricular Assist Device Implantation

BACKGROUND

Elevated pulmonary vascular resistance (PVR) is common in patients with advanced heart failure. PVR generally improves after left ventricular assist device (LVAD) implantation, but the rate of decrease has not been quantified and the patient characteristics most strongly associated with this improvement are unknown.

METHODS AND RESULTS

We analyzed 1581 patients from the Interagency Registry for Mechanically Assisted Circulatory Support registry who received a primary continuous-flow LVAD, had a baseline PVR of ≥3 Wood units (WU), and had PVR measured at least once postoperatively. Multivariable linear mixed effects modeling was used to evaluate independent associations between postoperative PVR and patient characteristics. PVR decreased by 1.53 WU (95% confidence interval [CI] 1.27-1.79 WU) per month in the first 3 months postoperatively, and by 0.066 WU (95% CI 0.060-0.070 WU) per month thereafter. Severe mitral regurgitation at any time during follow-up was associated with a 1.29 WU (95% CI 1.05-1.52 WU) higher PVR relative to absence of mitral regurgitation at that time. In a cross-sectional analysis, 15%-25% of patients had persistently elevated PVR of ≥3 WU at any given time within 36 months after LVAD implantation.

CONCLUSION

The PVR tends to decrease rapidly early after implantation, and only more gradually thereafter. Residual mitral regurgitation may be an important contributor to elevated postoperative PVR. Future research is needed to understand the implications of elevated PVR after LVAD implantation and the optimal strategies for prevention and treatment.

Hemodynamic effects of standard versus larger-capacity intraaortic balloon counterpulsation pumps

OBJECTIVE

Several recent trials have examined the clinical utility of intraaortic balloon counterpulsation pumps (IABPs) in cardiogenic shock and acute coronary syndromes. More recently, a larger-capacity 50 cc IABP was introduced into practice. No data comparing the hemodynamic effects of the 40 cc vs 50 cc IABP exist. Our aim was to explore the hemodynamic effects of the 50 cc IABP in real-world clinical practice.

METHODS

Demographic, hemodynamic, and laboratory data were retrospectively examined in 26 consecutive subjects treated with a 50 cc IABP and compared with 26 patients receiving a 40 cc IABP between 2012 and 2013. IABP tracings were analyzed within 24 hours of implantation in all patients. Pulmonary artery catheter data were available before and after IABP implantation in 20 subjects.

RESULTS

Baseline demographics, including body surface area, were similar between groups. Compared with the 40 cc IABP group, 50 cc IABP recipients showed higher augmented diastolic blood pressure, greater systolic unloading, and a larger reduction in pulmonary capillary occlusion pressure (PCOP). Percent diastolic augmentation was higher among 50 cc IABP recipients. Only 58% of subjects achieved <10 mm Hg of systolic unloading in the 40 cc group compared with 27% in the 50 cc group. For both the 40 cc and 50 cc IABPs, the magnitude of systolic unloading correlated inversely with PCOP and directly with the magnitude of diastolic augmentation.

CONCLUSION

In real-world practice, greater systolic unloading and diastolic augmentation were observed among 50 cc vs 40 cc IABP recipients. Future trials evaluating the clinical utility of the 50 cc IABP are required.

First report of a left ventricular assist device infection caused by Staphylococcus schleiferi subspecies coagulans: a coagulase-positive organism

Staphylococcus schleiferi subspecies coagulans is often misclassified as S. aureus given the production of a pseudocoagulase turning the tube coagulase test positive. It is therefore infrequently reported in the literature. We describe the first case of S. schleiferi subspecies coagulans left ventricular assist device infection in a patient awaiting heart transplantation.

Effects of a percutaneous mechanical circulatory support device for medically refractory right ventricular failure

BACKGROUND

Medically refractory right ventricular failure (MR-RVF) is associated with high in-hospital mortality and is managed with surgical assist devices, atrial septostomy, or extracorporeal membrane oxygenation. This study explored the hemodynamic effect associated with a percutaneous RV support device (pRVSD) for MR-RVF.

METHODS

Between 2008 and 2010, 9 patients with MR-RVF, defined as cardiogenic shock despite maximal medical therapy, were treated with a pRVSD. Medical records were reviewed for demographics, hemodynamic and laboratory data, and details of pRVSD implantation.

RESULTS

MR-RVF was due to severe sepsis in 1 patient (11.1%), post-cardiotomy syndrome in 2 (22.2%), and acute inferior wall myocardial infarction (IWMI) in 6 (66.7%). Five patients underwent right internal jugular-to-femoral cannulation, and 4 required bifemoral cannulation. No intra-procedural deaths or major vascular complications requiring surgical or peripheral intervention occurred. Time from admission to pRVSD implantation was 2.9 ± 3.3 days, with an average of 6516 ± 698 rotations/min, providing flow at 3.3 ± 0.4 liters/min. Mean duration of pRVSD activation was 3.1 ± 1.8 days. Compared with pre-procedural values, mean arterial pressure (57 ± 7 vs 75 ± 19 mm Hg, p < 0.05), right atrial pressure (22 ± 3 vs 15 ± 6 mm Hg, p < 0.05), cardiac index (1.5 ± 0.4 vs 2.3 ± 0.5 liters/min/m(2), p < 0.05), mixed venous oxygen saturation (40 ± 14 vs 58 ± 4 percent, p < 0.05), and RV stroke work (3.4 ± 3.9 vs 9.7 ± 6.8 g · m/beat, p < 0.05) improved significantly within 24 hours of pRVSD implantation. In-hospital mortality was 44% (n = 4). Time from admission to pRVSD placement was lower in patients who survived to hospital discharge (0.9 ± 0.8 days) vs non-survivors (4.8 ± 3.5 days; p = 0.04). All survivors presented with IWMI.

CONCLUSION

Use of a pRVSD for MR-RVF is feasible and associated with improved hemodynamics. Algorithms promoting earlier pRVSD use in MR-RVF warrant further investigation.

Thyroid nodule and thyroid cancer management pre- and post-cardiac transplantation

Thyroid nodules are common in the adult population. Widespread use of sensitive imaging studies often leads to their incidental discovery. Recent guidelines recommend thyroid-stimulating hormone determination and ultrasonography during initial nodule evaluation. Fine-needle aspiration is often performed to detect malignancy. However, the management of thyroid nodules in cardiac transplantation patients has not been directly addressed by recent guidelines. Confounding medications such as amiodarone and anti-coagulants present a management dilemma. The timing of fine-needle aspiration is crucial because (1) malignancy diagnosed pre-operatively usually precludes organ transplantation, and (2) patients undergoing solid-organ transplantation are at increased risk of developing de novo malignancies, including thyroid. With the rising incidence of thyroid cancer, donor-related malignancy will likely become a more prominent issue. This review addresses thyroid nodule management in the cardiac transplant population and provides recommendations for organ donation and transplantation in donors and recipients with thyroid cancer.

A cost-saving strategy for inpatient management of advanced decompensated heart failure patients: the Cardiomyopathy Unit

BACKGROUND

This article analyzes the relative costs and revenues of the Tufts Medical Center Cardiomyopathy Unit (CMU), a recent innovation for grouping and managing advanced decompensated heart failure patients.

METHODS AND RESULTS

We selected a retrospective sample of all patients with the primary diagnosis of heart failure, primary procedure of pulmonary artery catheterization, and with no other hospitalization procedures, admitted to Tufts Medical Center between 2000 and 2006. Regression models were used to estimate the cost for the intervention group and controls. Propensity analysis was used to test for selection bias in the comparison groups. We identified 114 hospitalizations meeting these criteria. Patients in the CMU group were well-balanced compared with controls with respect to demographic and clinical variables. Estimated direct medical costs for CMU and control groups were $11,817 (95% CI $7678-$16,106) and $17,236 (95% CI $11,199-$23,493), respectively. A similar pattern of cost differentials was displayed among propensity-matched sample groups. Net revenue was $12,609 (95% CI $9578-$16,845) and $15,627 (95% CI $11,871-$20,877) in the CMU and control groups, respectively.

CONCLUSIONS

The inpatient CMU may offer a lower cost and higher contribution margin alternative for the management of advanced heart failure patients requiring hemodynamic monitoring without other major inpatient procedures.

Influence of donor cocaine use on outcome after cardiac transplantation: analysis of the United Network for Organ Sharing Thoracic Registry

Heart transplantation from donors with a history of cocaine abuse remains controversial. Therefore, we examined the consequence of donor cocaine-use history on all-cause mortality and the development of coronary artery disease after heart transplantation. Using the United Network for Organ Sharing Thoracic Registry we identified 9,217 first-time heart-only adult transplant recipients between January 1999 and December 2003, and then divided this cohort into sub-groups based on the reported history of donor cocaine use. Multivariate analysis revealed no difference in mortality or development of coronary artery disease at 1 and 5 years between transplant recipients who received an organ from donors with a history of cocaine use when compared with donors having no history of cocaine use.

Current Treatment Options for CHF Management: Focus on the Renin-Angiotensin-Aldosterone System

Heart failure (HF) is highly prevalent in our society and its incidence is increasing in concert with the growing aged population. Experimental and clinical studies have consistently shown that HF is ameliorated by inhibition of the renin-angiotensin-aldosterone system (RAAS). Acknowledging that heightened activation of the RAAS contributes significantly to HF progression has led to the development of pharmacologic antagonists of RAAS components that have greatly improved both symptoms and prognosis of patients suffering from this syndrome. Angiotensin-converting enzyme (ACE) inhibitors represent the first developed agents that block the production of angiotensin II, and have been shown to be effective across a broad spectrum of patients with HF, including those with asymptomatic left ventricular dysfunction to overt HF. Initiation of ACE inhibitors prior to the onset of symptoms in those with left ventricular systolic dysfunction, and as early as feasible following a myocardial infarction, has been shown to reduce mortality and the development of overt HF in several clinical trials. Clinical data also support the use of angiotensin II receptor antagonists as an alternative to ACE inhibitors in patients who are allergic to, or intolerant of, ACE inhibitors. Agents that antagonize aldosterone via blockade of mineralocorticoid receptors improve clinical outcomes in patients with advanced HF or those with reduced ejection fraction and HF following an acute myocardial infarction. Maximally inhibiting the RAAS, in conjunction with other neurohormonal systems (eg, the sympathetic nervous system by b-adrenergic blockade), leads to improved clinical outcomes in HF, a highly prevalent and costly disease in our society.

Ventricular Assist Device Therapy Normalizes Inducible Nitric Oxide Synthase Expression and Reduces Cardiomyocyte Apoptosis in the Failing Human Heart

OBJECTIVES

We examined the effect of mechanical unloading with ventricular assist device (VAD) therapy on myocardial inducible nitric oxide synthase (iNOS) expression and cardiomyocyte apoptosis in patients with end-stage heart failure (HF).

BACKGROUND

Despite advances in medical therapy, HF continues to be a progressive and ultimately fatal disorder. High levels of iNOS expression are present in the myocardium of failing hearts, suggesting a potential role for iNOS in HF progression.

METHODS

Inducible NOS protein expression was analyzed by Western blotting and cardiomyocyte apoptosis by terminal deoxynucleotidyltransferase dUTP nick end-labeling (TUNEL) in myocardial samples from failing hearts. Included in these analyses were tissues from 9 patients at the time of transplantation (HF-transplant group), 10 patients at the time of VAD insertion (pre-VAD group), and 11 patients undergoing transplant after VAD support (post-VAD group). Seven control samples were obtained at autopsy.

RESULTS

Low or undetectable levels of iNOS were present in controls (0.005 +/- 0.002). The HF-transplant and pre-VAD myocardial specimens exhibited a marked increase in iNOS expression (1.48 +/- 0.34 and 1.29 +/- 0.26, respectively; p < 0.01 for both vs. controls). The increase in iNOS expression was reversed in the post-VAD group (0.36 +/- 0.16; p < 0.01 vs. HF-transplant and pre-VAD groups). The rate of TUNEL-positive cardiomyocytes was high in the pre-VAD group and significantly lower in the post-VAD group (0.64 +/- 0.15% in pre-VAD group and 0.16 +/- 0.07% in post-VAD group; p < 0.01). The iNOS levels correlated significantly with cardiomyocyte apoptosis (r = 0.66, p < 0.01).

CONCLUSIONS

Therapy with VAD normalizes iNOS expression in association with diminished cardiomyocyte apoptosis in the failing heart. Further work is required to define whether a causal relationship exists between iNOS and cardiomyocyte apoptosis.

The effect of recipient cytokine gene polymorphism on cardiac transplantation outcome

We determined the association between clinical outcomes after heart transplantation and gene polymorphism in five cytokines (tumor necrosis factor-alpha, transforming growth factor (TGF)-beta, interleukin-10, interleukin-6, and interferon-gamma) reported to influence expression in vitro. Ninety-five patients were studied. Cytokine genotyping was performed by sequence specific priming polymerase chain reaction. Clinical outcomes studied in the first posttransplant year included: (1) documented viral, bacterial, or fungal infection; (2) cytomegalovirus infection; (3) acute cellular rejection (International Society for Heart and Lung Transplantation > or = grade IIIA); (4) time to first rejection episode; and (5) the development of allograft vasculopathy. Patients with the TGF-beta genotype 10 T/T 25 G/G or 10 T/C 25 G/G had a longer time to first rejection (median time to first rejection episode 321 days) than those with the TGF-beta genotype 10C/C 25 G/C or 10 C/C 25 C/C (median time to first rejection 88 days). There was a trend toward a higher frequency of the tumor necrosis factor-alpha genotype -308 G/A or A/A in patients without infection (19/59, 32%) as compared with patients with infection (5/31, 16%). In both cases, these differences failed to reach significance when adjusted for multiple comparisons. No other significant association was found with clinical outcomes and polymorphisms in the five cytokine genes studied in this population.

Blood cyst of the mitral valve apparatus in a woman with a history of orthotopic liver transplantation

Blood cysts within the heart are rare findings in adults. We describe a case of a woman with a history of orthotopic liver transplantation who presented for an echocardiogram to evaluate a potential source of cerebrovascular embolism. A cystic mass attached to the submitral valve apparatus was identified by transthoracic and confirmed by transesophageal echocardiography. Surgical exploration and pathologic examination confirmed the mass to be a blood cyst attached to the chordal apparatus of the posterior papillary muscle. This case report highlights the use of echocardiography in diagnosing intracardiac blood cysts.

Comparison of survival and other complications after heart transplantation in patients taking amiodarone before surgery versus those not taking amiodarone

Concern exists regarding preoperative amiodarone use and complications occurring after heart transplantation (HT). During a 10-year period of performing HT, we found that patients treated with amiodarone before undergoing HT had decreased overall survival, required longer periods of ventilatory support, and were at increased risk for significant bleeding complications. These findings raise further concern about the use of amiodarone treatment in patients with heart failure before undergoing HT.

Preferences for treatment outcomes in patients with heart failure: symptoms versus survival

BACKGROUND

Patient preferences for congestive heart failure therapy outcomes may vary depending on the goals of improving symptoms versus survival, but this has not been extensively investigated. Our objective was to analyze patient preferences for congestive heart failure therapy outcomes based on the goals of symptom versus survival improvement.

METHODS AND RESULTS

This was a prospective, full-profile conjoint analysis study of individual preferences for congestive heart failure treatment outcomes. Conjoint analysis was based on ratings of 16 treatment-outcome profiles, each consisting of 4 attributes (tiredness, shortness of breath, depression, and survival) varied across 4 severity levels. Part-worths (utilities) and importance weights were calculated for each attribute to determine their relative contribution to the full-profile rating decision using standard full-profile conjoint analysis techniques. Fifty-one patients with congestive heart failure from our medical center (University of Pennsylvania Medical Center, Philadelphia, PA) and 47 age-, gender-, and race-matched control subjects were studied. Part-worths and importance weights were significantly different for shortness of breath and depression between patients and control subjects. Symptom-sensitive (n = 33) and survival-sensitive (n = 17) treatment outcome preference segments were identified within the patient group. Importance weights for symptom-sensitive versus survival-sensitive patients were as follows: tiredness 0.30+/-0.10 versus 0.16+/-0.09 (P < .01); shortness of breath 0.26+/-0.08 versus 0.21+/-0.08 (P = .07); depression 0.26+/-0.09 versus 0.19+/-0.09 (P = .01); and survival 0.18+/-0.07 versus 0.43+/-0.11 (P < .01). There were no significant predictors of which treatment outcome preference segment a patient belonged. Control subjects did not display similar preference segmentation.

CONCLUSIONS

Symptomatic congestive heart-failure patients were clustered into symptom-sensitive and survival-sensitive segments in a manner suggesting that treatment outcomes of improved symptoms were of greater importance to the majority than longer survival. A full understanding of these individual preferences may have important implications for the design of therapy for heart-failure patients.

Heart transplant center practice patterns affect access to donors and survival of patients classified as status 1 by the United Network of Organ Sharing

OBJECTIVE

To determine the effect of adult cardiac transplant center practice patterns within a single organ procurement organization on access to donors and survival for patients listed as United Network of Organ Sharing (UNOS) status 1.

METHODS

A total of 662 patients listed (January 1, 1992, through December 31, 1995) as UNOS status 1 for heart transplantation by the 4 adult cardiac transplant centers in an organ procurement organization were analyzed in a retrospective cohort study to determine differences in clinical outcomes.

RESULTS

The specific center at which an individual was listed as UNOS status 1 was a significant independent predictor of receiving a transplant (odds ratios for 3 centers vs center with highest likelihood = 0.73, 0.64, 0.35, respectively; P <. 01). Only 1 center had a significantly increased mortality rate compared with the other centers (odds ratio 2.03, P <.01).

CONCLUSION

Within a single regional organ procurement organization, cardiac transplant centers demonstrate significant variability in the likelihood of transplantation and survival for patients listed as UNOS status 1.

Histopathologic effects of radiofrequency catheter ablation in previously infarcted human myocardium

INTRODUCTION

The use of catheter-based radiofrequency (RF) ablation for the treatment of ventricular tachyarrhythmias due to previous myocardial infarction has been steadily increasing. The histopathologic changes caused by this technique are not well described in humans.

METHODS AND RESULTS

Three patients with hemodynamically tolerated ventricular tachycardias (VTs) due to previous myocardial infarction underwent endocardial mapping and catheter based RF ablation. All patients received between 5 and 11 RF lesions each of 60-second duration. One patient underwent myocardial resection of a left ventricular aneurysm 1 day following RF ablation, one expired 7 days after RF ablation, and one expired 9 months after RF ablation. None of the deaths occurred as a result of RF ablation. Pathologic specimens obtained early after RF ablation revealed areas of focal acute inflammation and fibrin deposition. Later specimens revealed several focal areas of fibrosis and granulation tissue. Specimens obtained late after RF ablation revealed a dense band of fibrosis, measuring 17 x 17 x 5 mm (1,250 mm3).

CONCLUSION

Catheter-based RF ablation of ischemic VT in humans causes lesions that initially resemble coagulation necrosis. This is followed by the development of an inflammatory infiltrate and, finally, the development of fibrosis. Repeated application of RF ablation may result in much larger lesions than have been previously reported.