Salutary Effects of the PULVAD, a Novel Implantable Counterpulsation Assist Device, on Cardiac Mechanoenergetics.

The Pressure Unloading Left Ventricular Assist Vevice (PULVAD) is a novel implantable counterpulsation LVAD, designed to provide ventricular unloading with augmentation of LV performance and retention of pulsatility. We assessed the effects of the PULVAD on hemodynamics and LV mechanoenergetics in seven farm pigs with acute ischemic heart failure. The PULVAD was implanted in the thorax and was connected to the ascending aorta. The PULVAD was pneumatically driven by a standard intra-aortic balloon pump console and was electrocardiogram-synchronized to provide LV pressure unloading along with diastolic aortic pressure augmentation. Hemodynamics, indices of LV mechanoenergetics, and coronary blood flow were measured without and after brief PULVAD support. PULVAD support decreased LV afterload and improved LV mechanical performance (increased ejection fraction, stroke volume, cardiac output and maximum elastance). The PULVAD concurrently reduced LV energy consumption (decreased stroke work and pressure-volume area) and optimized LV energetic performance (improved the ratio of stroke work to pressure-volume area). PULVAD support increased mean coronary blood flow, through dramatic augmentation of diastolic blood flow. In conclusion, the PULVAD unloads the failing LV, optimizes LV mechanoenergetics, and augments coronary blood flow. These salutary effects of short-term PULVAD support provide the foundation for long-term testing.

Pharmacologic inhibition of the mitochondrial Na+/Ca2+ exchanger protects against ventricular arrhythmias in a porcine model of ischemia-reperfusion.

BACKGROUND: The mitochondrial Na+/Ca2+ exchanger (mNCX) has been implicated in the pathogenesis of arrhythmogenicity and myocardial reperfusion injury, rendering its inhibition a potential therapeutic strategy. We examined the effects of CGP-37157, a selective mNCX inhibitor, on arrhythmogenesis, infarct size (IS), and no reflow area (NRA) in a porcine model of ischemia-reperfusion. METHODS: Forty pigs underwent myocardial ischemia for 60 minutes, followed by 2 hours of reperfusion. Animals were randomized to receive intracoronary infusion of 0.02 mg/kg CGP-37157 or vehicle, either before ischemia (n=17) or before reperfusion (n=17). Animals were monitored for arrhythmias. Myocardial area at risk (AR), IS, and NRA were measured by histopathology. RESULTS: AR, NRA, and IS were comparable between groups. Administration of CGP-37157 before ischemia resulted in the following: (a) suppression of ventricular tachyarrhythmias (events/pig: 1.5±1.1 vs 3.5±1.9, p=0.014), (b) easier cardioversion of ventricular tachyarrhythmias (defibrillations required for cardioversion of each episode: 2.6±2.3 vs 6.2±2.1, p=0.006), and (c) decreased maximal depression of the J point (0.75±0.27 mm vs 1.75±0.82 mm, p=0.007), compared to controls. Administration of CGP-37157 before reperfusion expedited ST-segment resolution; complete ST-segment resolution within 30 minutes of reperfusion was observed in 7/8 CGP-37157-treated animals versus 1/9 controls (p=0.003). CONCLUSIONS: In a porcine model of myocardial infarction, intracoronary administration of CGP-37157 did not decrease IS or NRA. However, it suppressed ventricular arrhythmias, decreased depression of the J point during ischemia and expedited ST-segment resolution after reperfusion. These findings motivate further investigation of pharmacologic mNCX inhibition as a potential therapeutic strategy to suppress arrhythmias in the injured heart.

Loop diuretics for chronic heart failure: a foe in disguise of a friend?

Loop diuretics are recommended for relieving symptoms and signs of congestion in patients with chronic heart failure and are administered to more than 80% of them. However, several of their effects have not systematically been studied. Numerous cohort and four interventional studies have addressed the effect of diuretics on renal function; apart from one prospective study, which showed that diuretics withdrawal is accompanied by increase in some markers of early-detected renal injury, all others converge to the conclusion that diuretics receipt, especially in high doses is associated with increased rates of renal dysfunction. Although a long standing perception has attributed a beneficial effect to diuretics in the setting of chronic heart failure, many cohort studies support that their use, especially in high doses is associated with adverse outcome. Several studies have used propensity scores in order to match diuretic and non-diuretic receiving patients; their results reinforce the notion that diuretics use and high diuretics dose are true risk factors and not disease severity markers, as some have suggested. One small, randomized study has demonstrated that diuretics decrease is feasible and safe and accompanied by a better prognosis. In conclusion, until elegantly designed, randomized trials, powered for clinical endpoints answer the unsettled issues in the field, the use of diuretics in chronic heart failure will remain subject to physicians' preferences and biases and not evidence based.

Arteriovenous renal replacement therapy in end-stage left-sided heart failure patients has a detrimental effect on patients with impaired right ventricular function.

OBJECTIVE: Chronic intermittent renal replacement therapy(RRT) is an alternate method of decongestion for patients presenting with diuretic-resistant, end-stage heart failure(HF) and cardiorenal syndrome. The optimal method of vascular access has not been confirmed. This study investigated the 6-month outcomes of patients with end-stage HF after the creation of arteriovenous communications (AVC) compared with other means of RRT. METHODS: We treated 40 patients with chronic, intermittent, ambulatory RRT, of whom 15 (37.5%; Group A) underwent creation of AVC, and 25 (62.5%; Group B) received intraperitoneal (n=6) or internal jugular catheters (n=19) with the goal of achieving body weight stabilization and relief from congestion. RESULTS: The characteristics of the two groups were similar. According to Cox regression analysis, the 6-month rate of death or re-hospitalization for HF was significantly higher in Group A (73%) than in Group B (44%); hazard ratio (HR): 2.58; 95% confidence interval (CI) 1.2-6.2; P=0.02. Over a 6-month follow-up, the cumulative survival was significantly shorter (P=0.03) in Group A (13.8±10 weeks) than in Group B (20.7±7 weeks). In the 15 patients who received AVC, the only independent predictor of adverse outcome at 6 months was serum total bilirubin concentration (HR 2.5; 95% CI 1.1-5.7, p=0.02), whereas in the 25 patients who underwent other means of RRT, pulmonary vascular resistance (PVR) was identified as a risk factor for hospitalization or death at 1-year follow-up (HR 1.26; 95% CI 1.1-1.57, p=0.04). CONCLUSION: In patients with end-stage HF, the creation of AVC for intermittent RRT was followed by a significant increase in morbidity and mortality in comparison to the safe and effective placement of permanent central venous catheters. Patients with elevated PVR seem to comprise a group at high risk for adverse outcomes after central catheter insertion.

Innate heart regeneration: endogenous cellular sources and exogenous therapeutic amplification.

INTRODUCTION: The -once viewed as heretical- concept of the adult mammalian heart as a dynamic organ capable of endogenous regeneration has recently gained traction. However, estimated rates of myocyte turnover vary wildly and the underlying mechanisms of cardiac plasticity remain controversial. It is still unclear whether the adult mammalian heart gives birth to new myocytes through proliferation of resident myocytes, through cardiomyogenic differentiation of endogenous progenitors or through both mechanisms. AREAS COVERED: In this review, the authors discuss the cellular origins of postnatal mammalian cardiomyogenesis and touch upon therapeutic strategies that could potentially amplify innate cardiac regeneration. EXPERT OPINION: The adult mammalian heart harbors a limited but detectable capacity for spontaneous endogenous regeneration. During normal aging, proliferation of pre-existing cardiomyocytes is the dominant mechanism for generation of new cardiomyocytes. Following myocardial injury, myocyte proliferation increases modestly, but differentiation of endogenous progenitor cells appears to also contribute to cardiomyogenesis (although agreement on the latter point is not universal). Since cardiomyocyte deficiency underlies almost all types of heart disease, development of therapeutic strategies that amplify endogenous regeneration to a clinically-meaningful degree is of utmost importance.

Continuous internal counterpulsation as a bridge to recovery in acute and chronic heart failure.

Cardiac recovery from cardiogenic shock (CS) and end-stage chronic heart failure (HF) remains an often insurmountable therapeutic challenge. The counterpulsation technique exerts numerous beneficial effects on systemic hemodynamics and left ventricular mechanoenergetics, rendering it attractive for promoting myocardial recovery in both acute and chronic HF. Although a recent clinical trial has questioned the clinical effectiveness of short-term hemodynamic support with intra-aortic balloon pump (IABP, the main representative of the counterpulsation technique) in CS complicating myocardial infarction, the issue remains open to further investigation. Moreover, preliminary data suggest that long-term IABP support in patients with end-stage HF is safe and may mediate recovery of left- or/and right-sided cardiac function, facilitating long-term weaning from mechanical support or enabling the application of other permanent, life-saving solutions. The potential of long-term counterpulsation could possibly be enhanced by implementation of novel, fully implantable counterpulsation devices.

Allogeneic cardiosphere-derived cells for myocardial regeneration: current progress and recent results.

Early-phase clinical testing of autologous cardiosphere-derived cells (CDCs) has yielded intriguing results, consistent with therapeutic myocardial regeneration. However, autologous therapy is associated with significant technical, timing, economic and logistic constraints, prompting researchers to explore the potential of allogeneic CDC therapy. CDCs exhibit a favorable immunologic antigenic profile and are hypoimmunogenic in vitro. Preclinical studies in immunologically mismatched animals demonstrate that allogeneic CDC transplantation without immunosuppression is safe and produces sustained functional and structural benefits through stimulation of endogenous regenerative pathways. Currently, allogeneic human CDCs are being tested clinically in the ALLSTAR and DYNAMIC trials. Potential establishment of clinical safety and efficacy of allogeneic CDCs combined with generation of highly standardized, 'off-the-shelf' allogeneic cellular products would facilitate broad clinical adoption of cell therapy.

Late-onset right ventricular dysfunction after mechanical support by a continuous-flow left ventricular assist device.

BACKGROUND: Right heart failure (RHF) is a serious post-operative complication of left ventricular assist device (LVAD) implantation, with significant morbidity and mortality. Many clinical, hemodynamic and laboratory variables have been shown to have prognostic value for appearance of RHF. We sought to investigate the incidence of new-onset right ventricular dysfunction (RVD) complicating the long-term use of LVADs. METHODS: We retrospectively examined all patients supported with a continuous-flow LVAD for >1 year at our center. RESULTS: Twenty patients (mean age 54 ± 10 years, 95% men, 60% with ischemic cardiomyopathy, left ventricular ejection fraction 22 ± 6%, pulmonary capillary wedge pressure 23.5 ± 7.5 mm Hg, brain natriuretic peptide [BNP] 1,566 ± 1,536 pg/ml, serum creatinine 1.6 ± 0.64 mg/dl, furosemide dose 643 ± 410 mg/day) underwent long-term mechanical support as destination therapy support with a continuous-flow LVAD (HeartMate II) at our center. During follow-up (1,219 ± 692 days), 9 patients (45%) manifested symptoms and signs of RVD (increase in right atrial pressure [RAP], BNP and daily furosemide dose compared with the early post-operative period). In these patients, RAP was increased by 6.6 ± 2.6 mm Hg and BNP by 526 ± 477 pg/ml, whereas furosemide dose increased by 145 ± 119 mg. The mean and median times of RVD onset were 2.3 ± 1.5 and 2.1 years, respectively, after LVAD implantation (range 0.4 to 4.8 years). Four of these patients (44.4%) demonstrated further deterioration of RV function and died 73 ± 106 days (median 25 days, range 9 to 231 days) after first manifestation of RVD. Comparisons of baseline variables regarding medical history and clinical status did not demonstrate significant differences between the patients with or without RVD, including parameters related to RV function at the time of implantation. CONCLUSIONS: Late-onset RVD is a complication of LVAD support, which can manifest several months to years from device implantation. This complication has significant adverse implications with regard to patient outcome. Prognostic factors need to be identified to follow and treat high-risk patients more efficiently.

Prolonged intra-aortic balloon pump support in biventricular heart failure induces right ventricular reverse remodeling.

BACKGROUND: Right ventricular dysfunction is associated with high morbidity and mortality in candidates for left ventricular assist device (LVAD) implantation or cardiac transplantation. METHODS: We examined the effects of prolonged intra-aortic balloon pump (IABP) support on right ventricular, renal and hepatic functions in patients presenting with end-stage heart failure. RESULTS: Between March 2008 and June 2013, fifteen patients (mean age = 49.5 years; 14 men) with end-stage systolic heart failure (HF), contraindications for any life saving procedure (conventional cardiac surgery, heart transplantation, LVAD implantation) and right ventricular dysfunction were supported with the IABP. The patients remained on IABP support for a mean of 73 ± 50 days (median 72, range of 13-155). We measured the echocardiographic and hemodynamic changes in right ventricular function, and the changes in serum creatinine and bilirubin concentrations before and during IABP support. Mean right atrial pressure decreased from 12.7 ± 6.5 to 3.8 ± 3.3 (P < 0.001) and pulmonary artery pressure decreased from 35.7 ± 10.6 to 25 ± 8.4 mmHg (P = 0.001), while cardiac index increased from 1.5 ± 0.4 to 2.2 ± 0.7 l/m(2)/min (P = 0.003) and right ventricular stroke work index from 485 ± 228 to 688 ± 237 mmHg × ml/m(2) (P = 0.043). Right ventricular end-diastolic diameter decreased from 34.0 ± 6.5 mm to 27.8 ± 6.2 mm (P < 0.001) and tricuspid annular systolic tissue Doppler velocity increased from 9.6 ± 2.4 cm/s to 11.1 ± 2.3 cm/s (P = 0.029). Serum creatinine and bilirubin decreased from 2.1 ± 1.3 to 1.4 ± 0.6 mg/dl and 2.0 ± 1.0 to 0.9 ± 0.5 mg/dl, respectively (P = 0.002 and P < 0.001, respectively). CONCLUSIONS: Prolonged IABP support of patients presenting with end-stage heart failure and right ventricular dysfunction induced significant improvement in right ventricular and peripheral organ function.

High furosemide dose has detrimental effects on survival of patients with stable heart failure.

INTRODUCTION: High doses of furosemide for heart failure (HF) have been correlated with an increased mortality, though whether they are a marker of disease severity or an independent predictor is unknown. We hypothesized that, in patients presenting with stable HF, the likelihood of long-term major adverse clinical events is increased by higher furosemide doses. METHODS: We retrospectively recorded the doses of furosemide prescribed to 173 consecutive, clinically stable patients during a first ambulatory HF department visit. The low-dose group included 103 patients treated with 80 mg and the high-dose group included 70 patients treated with >80 mg of furosemide daily. Proportional hazard regression analyses were performed with single and multiple variables in search of correlates of long-term adverse clinical events. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated. RESULTS: The baseline characteristics of the 2 groups were similar, except for estimated glomerular filtration rate, which was higher in the low- than the high-dose group (72.9 ± 19.4 vs. 60.8 ± 22.0 mL/min/ m2, p<0.001). The 3-year survival free from the composite endpoint was significantly higher in the lowdose group than in the high-dose group (93.1% vs. 60.0%, p<0.001). By multiple variable analysis, highdose furosemide was an independent predictor of an adverse outcome at 3 years (adjusted HR: 15.25; 95% CI:1.06-219.39, p=0.045). The incidence of deterioration of renal function and episodes of hypokalemia during follow up was also higher in the high furosemide dose (73.2% vs. 48.3, p=0.003, and 43.1% vs. 6.5%, p<0.001, respectively). CONCLUSIONS: High doses of furosemide administered in order to stabilize HF patients and continued thereafter are associated with an adverse clinical outcome.

Dabigatran etexilate as second-line therapy in patients with a left ventricular assist device.

INTRODUCTION: Administration of anticoagulation is mandatory in patients with left ventricular assist devices (LVADs). Vitamin K antagonists require regular monitoring and dosage adjustment. Dabigatran administered in a standard dose twice daily is more convenient and achieves a stable anticoagulant effect, but its effectiveness and safety in patients with LVADs has not been investigated. The objective of the present study was to evaluate whether dabigatran can be used safely as a second-line anticoagulation option in patients with a HeartMate II (HMII) LVAD. METHODS: The study population consisted of 7 consecutive patients with end-stage heart failure who underwent HMII implantation and sequentially received acenocoumarol and dabigatran. Occurrence of stroke, systematic embolism, device thrombosis and major or life-threatening bleeding were included in the analysis. An acute decrease in plasma hemoglobin >2 g/dL or a need for transfusion of at least 2 units of packed red blood cells (PRBC) was defined as major bleeding, while an acute decrease in plasma hemoglobin >5 g/dL, fatal, symptomatic intracranial bleed, need for transfusion of at least 4 units PRBC, or association with hypotension requiring the use of intravenous inotropic agents or surgical intervention was defined as life-threatening bleeding. RESULTS: The duration of follow up was 1564 ± 292 days. Patients received acenocoumarol for 855 ± 246 days, followed by dabigatran for 708 ± 368 days. The rates of thromboembolic events were similar under dabigatran and acenocoumarol treatment: strokes, 0.094 vs. 0 /patient-year, p=0.36; systemic embolism, no event in either group; and device thrombosis, 0.053 vs. 0.258 events/patient-year, p=0.19, respectively. Compared to an adjusted acenocoumarol dose, the standard dabigatran dose resulted in similar rates of life-threatening bleeding, but significantly lower rates of major bleeding (0.18 vs. 0.27 bleeds/patient-years, p=0.76, and 0.047 vs. 0.547, p<0.001, for dabigatran and acenocoumarol, respectively). CONCLUSIONS: The safe and effective use of dabigatran as a second-line anticoagulation therapy in patients with HMII seems feasible. However, these data must be confirmed in a randomized study.

Outpatient management of chronic heart failure.

INTRODUCTION: Heart failure (HF) treatment attracts a share of intensive research because of its poor HF prognosis. In the past decades, the prognosis of HF has improved considerably, mainly as a consequence of the progress that has been made in the pharmacological management of HF. AREAS COVERED: This article reviews the outpatient pharmacological management of chronic HF due to left ventricular systolic dysfunction and offers recommendations on the use of various drugs. In addition, the present article attempts to provide practical therapeutic algorithms based on current clinical strategies. EXPERT OPINION: Continued research directed toward identifying factors associated with high pharmacotherapy guideline adherence and understanding of variants that influence response to drugs will hopefully halt or reverse the major pathophysiological mechanisms involved in this syndrome.

Red blood cell distribution width is a significant prognostic marker in advanced heart failure, independent of hemoglobin levels.

INTRODUCTION: Advanced heart failure (HF) is associated with increased morbidity and mortality; traditionally used prognostic factors often fail to predict the outcome. Increased red blood cell distribution width (RDW) has recently been recognized as an important unfavorable prognostic factor in HF, independent of anemia; however, the role of RDW in patients with advanced HF has not yet been investigated. METHODS: Eighty consecutive patients with stage D heart failure, recently hospitalized for HF decompensation, were enrolled. A Cox proportional-hazard model was used to determine whether RDW was independently associated with outcome. RESULTS: At study entry, ejection fraction (EF), pulmonary capillary wedge pressure (PCWP), hemoglobin (Hb) and RDW were 25 ± 8.6%, 27.5 ± 8 mmHg, 12.5 ± 1.9 mg/dL and 18 ± 3.5% (normal <14.5%) respectively. At 6 months, 44 patients (55%) had died. In this patient population, EF (p=0.45), PCWP (p=0.106), age (p=0.54), albumin (0.678), iron (p=0.37), creatinine (p=0.432), iron deficiency defined by bone marrow aspiration (p=0.37), bilirubin (p=0.422), peak VO2 (p=0.057) and Hb (p=0.95) were not significant predictors of a worse outcome. However, RDW was a significant marker for adverse prognosis (p=0.007, HR: 1.14, CI: 1.04-1.24) and retained its prognostic significance even when corrected for Hb values (HR: 1.15, CI: 1.05-1.27, p=0.003). CONCLUSIONS: RDW is a significant prognostic factor for an adverse outcome in patients with advanced stage heart failure who have experienced recent decompensation, independent of the presence of anemia or malnutrition, and is superior to more traditionally used indices. RDW may be associated with severe disease by reflecting subtle metabolic and proinflammatory abnormalities in HF.

Current and future applications of the intra-aortic balloon pump.

PURPOSE OF REVIEW: The intra-aortic balloon pump (IABP) has been used for more than 40 years. Although recommended in a wide variety of clinical settings, most of these indications are not evidence-based. This review focuses on studies challenging these traditional indications and evaluates potentially new applications of intra-aortic counterpulsation. RECENT FINDINGS: Recent studies have failed to confirm an improvement in clinical outcomes conferred by the IABP in patients developing cardiogenic shock after acute myocardial infarction. This issue is in need of further investigations. While conflicting results of several retrospective studies and meta-analyses have been published regarding the performance of the IABP in high-risk percutaneous coronary interventions, it has recently been found to improve the long-term clinical outcomes of patients in whom it was implanted before the procedure. Small, single-center studies have reported the use of the IABP as a bridge to transplantation or candidacy for left-ventricular assist device implantation. The recently reported feasibility and safety of its insertion via the subclavian or axillary arteries will facilitate these applications. SUMMARY: The revisiting of available data and the performance of new, thoughtfully designed trials should clarify the proper indications for the IABP.

Counterpulsation: a concept with a remarkable past, an established present and a challenging future.

The intra-aortic balloon pump (IABP), which is the main representative of the counterpulsation technique, has been an invaluable tool in cardiologists' and cardiac surgeons' armamentarium for approximately half a century. The IABP confers a wide variety of vaguely understood effects on cardiac physiology and mechano-energetics. Although, the recommendations for its use are multiple, most are not substantially evidence-based. Indicatively, the results of recently performed prospective studies have put IABP's utility in the setting of post-infarction cardiogenic shock into question. However, the particular issue remains open to further research. IABP support in high-risk patients undergoing PCI is associated with favorable long-term clinical outcome. In cardiac surgery, the use of IABP in cases of peri-operative low-output syndrome, refractory angina or ischemia-related mechanical complications is a usual, but poorly justified strategy. Anecdotal cases of treatment of incessant ventricular arrhythmias, reversal of right ventricular dysfunction and partial myocardial recovery have also been reported with its use. Converging data demonstrate the potential of safe long-term IABP support as a bridge to decision making or a bridge to transplantation modality in patients with heart failure. The feasibility of IABP insertion via other than the femoral artery sites enhances this potential. Despite the fact that several other counterpulsation devices have been developed and tested overtime none has managed to substitute the IABP, which continues to be most frequently used mechanical assist device.