[Support of damaged heart with the Impella pump]

Temporary mechanical circulatory support is increasingly used, particularly in patients with cardiogenic shock or during high-risk percutaneous coronary interventions. In the last five years there have been numerous developments in this field. Experience has been gained from usage of temporary heart pumps, and new pumps have arrived on the market. Until recently, the intra-aortal balloon pump was the standard treatment for patients with cardiogenic shock; however, results from the latest research into the effectiveness of this pump have rendered it less popular. An alternative modality is the Impella system. Since 2012, usage of a heart pump in cardiogenic shock treatment is reimbursed by healthcare insurers in the Netherlands. Recently, the FDA approved the Impella system for said indication.

Extracorporeal life support during cardiac arrest and cardiogenic shock: a systematic review and meta-analysis

Purpose

Veno-arterial extracorporeal life support (ECLS) is increasingly used in patients during cardiac arrest and cardiogenic shock, to support both cardiac and pulmonary function. We performed a systematic review and meta-analysis of cohort studies comparing mortality in patients treated with and without ECLS support in the setting of refractory cardiac arrest and cardiogenic shock complicating acute myocardial infarction.

Methods

We systematically searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials and the publisher subset of PubMed updated to December 2015. Thirteen studies were included of which nine included cardiac arrest patients (n = 3098) and four included patients with cardiogenic shock after acute myocardial infarction (n = 235). Data were pooled by a Mantel-Haenzel random effects model and heterogeneity was examined by the I² statistic.

Results

In cardiac arrest, the use of ECLS was associated with an absolute increase of 30 days survival of 13 % compared with patients in which ECLS was not used [95 % CI 6–20 %; p < 0.001; number needed to treat (NNT) 7.7] and a higher rate of favourable neurological outcome at 30 days (absolute risk difference 14 %; 95 % CI 7–20 %; p < 0.0001; NNT 7.1). Propensity matched analysis, including 5 studies and 438 patients (219 in both groups), showed similar results. In cardiogenic shock, ECLS showed a 33 % higher 30-day survival compared with IABP (95 % CI, 14–52 %; p < 0.001; NNT 13) but no difference when compared with TandemHeart/Impella (−3 %; 95 % CI −21 to 14 %; p = 0.70; NNH 33).

Conclusions

In cardiac arrest, the use of ECLS was associated with an increased survival rate as well as an increase in favourable neurological outcome. In the setting of cardiogenic shock there was an increased survival with ECLS compared with IABP.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-016-4536-8) contains supplementary material, which is available to authorized users.

Helium ventilation for treatment of post-cardiac arrest syndrome: A safety and feasibility study

AIM

Besides supportive care, the only recommended treatment for comatose patients after cardiac arrest is target temperature management. Helium reduces ischaemic injury in animal models, and might ameliorate neurological injury in patients after cardiac arrest. As no studies exist on the use of helium in patients after cardiac arrest we investigated whether this is safe and feasible.

METHODS

The study was an open-label single arm intervention study in a mixed-bed academic intensive care unit. We included 25 patients admitted after circulatory arrest, with a presenting rhythm of ventricular fibrillation or pulseless tachycardia, return of spontaneous circulation within 30min and who were treated with hypothermia. Helium was administrated in a 1:1 mix with oxygen for 3h. A safety committee reviewed all ventilation problems, complications and causes of mortality.

RESULTS

Helium ventilation was started 4:59±0:52 (mean±SD)h after circulatory arrest. In one patient, helium ventilation was discontinued prematurely due to oxygenation problems. This was caused by pre-existing pulmonary oedema, and imposed limitations to PEEP and FiO2 by the study protocol, rather than the use of helium ventilation. Sixteen (64%) patients had a favourable neurological outcome.

CONCLUSIONS

We found that helium ventilation is feasible and can be used safely in patients treated with hypothermia after cardiac arrest. No adverse events related to the use of helium occurred during the three hours of administration.

Effect of extracorporeal CO2 removal on right ventricular and hemodynamic parameters in a patient with acute respiratory distress syndrome

We present a female patient with severe acute respiratory distress syndrome (ARDS) necessitating intubation and mechanical ventilation on the intensive care unit (ICU). High ventilatory pressures were needed because of hypoxia and severe hypercapnia with respiratory acidosis, resulting in right ventricular dysfunction with impaired haemodynamic stability. A veno-venous extracorporeal CO2 removal (ECCO2R) circuit was initiated, effectively eliminating carbon dioxide while improving oxygenation and enabling a reduction in applied ventilatory pressures. We noted a marked improvement of right ventricular function with restoration of haemodynamic stability. Within one week, the patient was weaned from both ECCO2R and mechanical ventilation. Besides providing adequate gas exchange, extracorporeal assist devices may be helpful in ameliorating right ventricular dysfunction during ARDS.

Low tidal volume ventilation ameliorates left ventricular dysfunction in mechanically ventilated rats following LPS-induced lung injury

Background

High tidal volume ventilation has shown to cause ventilator-induced lung injury (VILI), possibly contributing to concomitant extrapulmonary organ dysfunction. The present study examined whether left ventricular (LV) function is dependent on tidal volume size and whether this effect is augmented during lipopolysaccharide(LPS)-induced lung injury.

Methods

Twenty male Wistar rats were sedated, paralyzed and then randomized in four groups receiving mechanical ventilation with tidal volumes of 6 ml/kg or 19 ml/kg with or without intrapulmonary administration of LPS. A conductance catheter was placed in the left ventricle to generate pressure-volume loops, which were also obtained within a few seconds of vena cava occlusion to obtain relatively load-independent LV systolic and diastolic function parameters. The end-systolic elastance / effective arterial elastance (Ees/Ea) ratio was used as the primary parameter of LV systolic function with the end-diastolic elastance (Eed) as primary LV diastolic function.

Results

Ees/Ea decreased over time in rats receiving LPS (p = 0.045) and high tidal volume ventilation (p = 0.007), with a lower Ees/Ea in the rats with high tidal volume ventilation plus LPS compared to the other groups (p < 0.001). Eed increased over time in all groups except for the rats receiving low tidal volume ventilation without LPS (p = 0.223). A significant interaction (p < 0.001) was found between tidal ventilation and LPS for Ees/Ea and Eed, and all rats receiving high tidal volume ventilation plus LPS died before the end of the experiment.

Conclusions

Low tidal volume ventilation ameliorated LV systolic and diastolic dysfunction while preventing death following LPS-induced lung injury in mechanically ventilated rats. Our data advocates the use of low tidal volumes, not only to avoid VILI, but to avert ventilator-induced myocardial dysfunction as well.

Impact of Positive End-Expiratory Pressure on Thermodilution-Derived Right Ventricular Parameters in Mechanically Ventilated Critically Ill Patients

OBJECTIVES

To examine the effect of positive end-expiratory pressure (PEEP) on right ventricular stroke volume variation (SVV), with possible implications for the number and timing of pulmonary artery catheter thermodilution measurements.

DESIGN

Prospective, clinical pilot study.

SETTING

Academic medical center.

PARTICIPANTS

Patients who underwent volume-controlled mechanical ventilation and had a pulmonary artery catheter.

INTERVENTION

PEEP was increased from 5-to-10 cmH2O and from 10-to-15 cmH2O with 10-minute intervals, with similar decreases in PEEP, from 15-to-10 cmH2O and 10-to-5 cmH2O.

MEASUREMENTS AND MAIN RESULTS

In 15 patients, right ventricular parameters were measured using thermodilution at 10% intervals of the ventilatory cycle at each PEEP level with a rapid-response thermistor. Mean right ventricular stroke volume and end-diastolic volume declined during incremental PEEP and normalized on return to 5 cmH2O PEEP (p = 0.01 and p = 0.001, respectively). Right ventricular SVV remained unaltered by changes in PEEP (p = 0.26), regardless of incremental PEEP (p = 0.15) or decreased PEEP (p = 0.12). The coefficients of variation in the ventilatory cycle of all other thermodilution-derived right ventricular parameters also were unaffected by changes in PEEP.

CONCLUSIONS

This study showed that increases in PEEP did not affect right ventricular SVV in critically ill patients undergoing mechanical ventilation despite reductions in mean right ventricular stroke volume and end-diastolic volume. This could be explained by cyclic counteracting changes in right ventricular preloading and afterloading during the ventilatory cycle, independent of PEEP. Changes in PEEP did not affect the number and timing of pulmonary artery catheter thermodilution measurements.

Plasma-derived human C1-esterase inhibitor does not prevent mechanical ventilation-induced pulmonary complement activation in a rat model of Streptococcus pneumoniae pneumonia

Mechanical ventilation has the potential to cause lung injury, and the role of complement activation herein is uncertain. We hypothesized that inhibition of the complement cascade by administration of plasma-derived human C1-esterase inhibitor (C1-INH) prevents ventilation-induced pulmonary complement activation, and as such attenuates lung inflammation and lung injury in a rat model of Streptococcus pneumoniae pneumonia. Forty hours after intratracheal challenge with S. pneumoniae causing pneumonia rats were subjected to ventilation with lower tidal volumes and positive end-expiratory pressure (PEEP) or high tidal volumes without PEEP, after an intravenous bolus of C1-INH (200 U/kg) or placebo (saline). After 4 h of ventilation blood, broncho-alveolar lavage fluid and lung tissue were collected. Non-ventilated rats with S. pneumoniae pneumonia served as controls. While ventilation with lower tidal volumes and PEEP slightly amplified pneumonia-induced complement activation in the lungs, ventilation with higher tidal volumes without PEEP augmented local complement activation more strongly. Systemic pre-treatment with C1-INH, however, failed to alter ventilation-induced complement activation with both ventilation strategies. In accordance, lung inflammation and lung injury were not affected by pre-treatment with C1-INH, neither in rats ventilated with lower tidal volumes and PEEP, nor rats ventilated with high tidal volumes without PEEP. Ventilation augments pulmonary complement activation in a rat model of S. pneumoniae pneumonia. Systemic administration of C1-INH, however, does not attenuate ventilation-induced complement activation, lung inflammation, and lung injury.

Pulse pressure variation does not reflect stroke volume variation in mechanically ventilated rats with lipopolysaccharide-induced pneumonia

1. The present study examined the relationship between centrally measured stroke volume variation (SVV) and peripherally derived pulse pressure variation (PPV) in the setting of increased total arterial compliance (CA rt ). 2. Ten male Wistar rats were anaesthetized, paralysed and mechanically ventilated before being randomized to receive intrapulmonary lipopolysaccharide (LPS) or no LPS. Pulse pressure (PP) was derived from the left carotid artery, whereas stroke volume (SV) was measured directly in the left ventricle. Values of SVV and PPV were calculated over three breaths. Balloon inflation of a catheter positioned in the inferior vena cava was used, for a maximum of 30 s, to decrease preload while the SVV and PPV measurements were repeated. Values of CA rt were calculated as SV/PP. 3. Intrapulmonary LPS increased CA rt and SV. Values of SVV and PPV increased in both LPS-treated and untreated rats during balloon inflation. There was a correlation between SVV and PPV in untreated rats before (r = 0.55; P = 0.005) and during (r = 0.69; P < 0.001) occlusion of the vena cava. There was no such correlation in LPS-treated rats either before (r = -0.08; P = 0.70) or during (r = 0.36; P = 0.08) vena cava occlusion. 4. In conclusion, under normovolaemic and hypovolaemic conditions, PPV does not reflect SVV during an increase in CA rt following LPS-induced pneumonia in mechanically ventilated rats. Our data caution against their interchangeability in human sepsis.

Conventional hemodynamic resuscitation may fail to optimize tissue perfusion: an observational study on the effects of dobutamine, enoximone, and norepinephrine in patients with acute myocardial infarction complicated by cardiogenic shock

AIM

To investigate the effects of inotropic agents on parameters of tissue perfusion in patients with cardiogenic shock.

METHODS AND RESULTS

Thirty patients with cardiogenic shock were included. Patients received dobutamine, enoximone, or norepinephrine. We performed hemodynamic measurements at baseline and after titration of the inotropic agent until cardiac index (CI) ≥ 2.5 L.min-1.m(-2) or mixed-venous oxygen saturation (SvO2) ≥ 70% (dobutamine or enoximone), and mean arterial pressure (MAP) ≥ 70 mmHg (norepinephrine). As parameters of tissue perfusion, we measured central-peripheral temperature gradient (delta-T) and sublingual perfused capillary density (PCD). All patients reached predefined therapeutic targets. The inotropes did not significantly change delta-T. Dobutamine did not change PCD. Enoximone increased PCD (9.1 [8.9-10.2] vs. 11.4 [8.4-13.9] mm.mm(-2); p<0.05), and norepinephrine tended to decrease PCD (9.8 [8.5-11.9] vs. 8.8 [8.2-9.6] mm.mm-2, p = 0.08). Fifteen patients (50%) died within 30 days after admission. Patients who had low final PCD (≤ 10.3 mm.mm-2; 64%) were more likely to die than patients who had preserved PCD (>10.3 mm.mm(-2); mortality 72% vs. 17%, p = 0.003).

CONCLUSION

This study demonstrates the effects of commonly used inotropic agents on parameters of tissue perfusion in patients with cardiogenic shock. Despite hemodynamic optimization, tissue perfusion was not sufficiently restored in most patients. In these patients, mortality was high. Interventions directed at improving microcirculation may eventually help bridging the gap between improved hemodynamics and dismal patient outcome in cardiogenic shock.

Mechanical circulatory support with the Impella 5.0 device for postcardiotomy cardiogenic shock: a three-center experience

AIM

Postcardiotomy cardiogenic shock (PCCS) is associated with high mortality rates, despite full conventional treatment. Although the results of treatment with surgically implantable ventricular assist devices have been encouraging, the invasiveness of this treatment limits its applicability. Several less invasive devices have been developed, including the Impella system. The objective of this study was to describe our three-center experience with the Impella 5.0 device in the setting of PCCS.

METHODS

From January 2004 through December 2010, a total of 46 patients were diagnosed with treatment-refractory PCCS and treated with the Impella 5.0 percutaneous left ventricular assist device at three european heart centers. Baseline and follow-up characteristics were collected retrospectively and entered into a dedicated database.

RESULTS

Within the study cohort of 46 patients, mean logistic and additive EuroSCORES were 24 ± 19 and 10 ± 4. The majority of patients underwent coronary artery bypass grafting (48%) or combined surgery (33%). Half of all patients had been treated with an intra-aortic balloon pump before 5.0-implantation, 1 patient had been treated with an Impella 2.5 device. All patients were on mechanical ventilation and intravenous inotropes. The Kaplan-Meier estimate of overall 30-day survival was 39.5%.

CONCLUSION

Thirty-day survival rates for patients with PCCS, refractory to aggressive conventional treatment and treated with the Impella 5.0 device, are comparable to those reported in studies evaluating surgically implantable VADs, whereas the Impella system is much less invasive. Therefore, mechanical circulatory support with the Impella 5.0 device is a suitable treatment modality for patients with severe PCCS.

Haemodynamic monitoring of morbidly obese intensive care unit patients

Because of technical and practical difficulties in relation to increased body size, haemodynamic monitoring of morbidly obese critically ill patients (i.e. body mass index &#8805;40 kg÷m2) may be challenging. Obese and non-obese patients are not so different with respect to haemodynamic monitoring and goals. The critical care physician, however, should be aware of the basic principles of the monitoring tools used. The theoretical assumptions and calculations of these tools could be invalid because of the high body weight and fat distribution. Although the method of assessing haemodynamic data may be more complex in morbidly obese patients, its interpretation should not be different from that in non-obese patients. Indeed, when indexed for body surface area or (predicted) lean body mass, reliable haemodynamic data are comparable etween obese and non-obese individuals.

IgM antibodies against apoptotic cells and phosphorylcholine in patients with acute myocardial infarction in relation to infarct size and inflammatory response

BACKGROUND

Natural IgM antibodies, and anti-phosphorylcholine IgM (anti-PC IgM) in particular, may modulate the pathogenesis of acute myocardial infarction (AMI).

OBJECTIVES

An exploratory study was conducted to evaluate the hypothesis that circulating anti-PC IgM and IgM binding to damaged cells increases the infarct size and post-infarct inflammatory response in patients with AMI.

MATERIAL AND METHODS

Plasma IgM binding to apoptotic cells (anti-apop IgM) and anti-PC IgM levels were compared in plasma samples from 50 patients with AMI and 46 healthy controls after correction for hemodilution. The cumulative release of cardiac markers LDH (lactate dehydrogenase), CK or CK-MB in human myocardium at 48 hours was used as an indication of infarct size. The circulating levels of mediators such as activated complement, C-reactive protein (CRP), interleukin-6 (IL6), interleukin-8 (IL8) and secretory phospholipase A2 (sPLA2) were used to assess the post-infarct inflammatory response. Patients with low (< median) and high (> median) levels of anti-apop IgM or anti-PC IgM were compared regarding infarct size and post-infarct inflammatory response. An electrocardiographical scoring system (Selvester score) was used to asses myocardial infarct size in patients with a first AMI (n = 24).

RESULTS

AMI patients demonstrated lower levels of anti-PC IgM on admission (p < 0.01) and at 48 hours (p < 0.001) when compared to the healthy controls, whereas anti-apop IgM levels were comparable to control levels. In patients with a first infarct, patients with levels of anti-PC IgM above the median demonstrated larger electrocardiographic infarct sizes (p = 0.04) and a more pronounced response of the acute phase protein sPLA2 (p = 0.06), with a similar post-infarct course of LDH, CK and CK-MB.

CONCLUSIONS

These findings suggest that anti-PC IgM plasma levels may participatie in amplifying the inflammatory response of the ischemic heart and contribute to infarct size. However, the levels of anti-PC IgM in patients with AMI in this study do not show a significant effect on cardiac markers LDH, CK and CK-MB. Hence, conclusive evidence is not provided by this limited cohort.

Left-sided native valve Staphylococcus aureus endocarditis

Despite improved diagnostic tools and expanded treatment options, left-sided native valve endocarditis caused by Staphylococcus aureus infection remains a serious and destructive disease. The high morbidity and mortality, however, can be reduced by early recognition, correct diagnosis, and appropriate treatment. In the following article, we discuss the clinical presentation, diagnostic workup and treatment of infective endocarditis, thereby reviewing the current guidelines. Blood cultures and echocardiography are the cornerstones of diagnosis in identifying infective endocarditis but are no substitute for clinical judgement. The modified Duke criteria may facilitate the diagnostic process, but clinical evaluation remains crucial.

[The Impella system for mechanical support and myocardial recovery]

Mechanical circulatory support has become an increasingly important therapeutic option in the field of cardiology, both with regard to treatment of patients in cardiogenic shock and protection against haemodynamic instability during high-risk percutaneous coronary intervention (PCI). The intra-aortic balloon pump (IABP) is the current standard treatment for mechanical circulatory support. However, its efficacy seems limited, both in acute and elective settings. The Impella system is a new technique which may be a suitable alternative to IABP treatment. The Impella is a small micro-axial, catheter-mounted cardiac pump, which is inserted through the femoral artery. Safety and efficacy of Impella treatment have been demonstrated during elective high-risk PCI. In the setting of cardiogenic shock, mechanical support with the Impella may lead to partial recovery of left ventricular function, especially when Impella treatment is applied according to a carefully designed pre-specified protocol..

Intra-operative assessment of human pulmonary alveoli in vivo using Sidestream Dark Field imaging: a feasibility study

BACKGROUND

In vivo videomicroscopy has been used for years to visualize subpleural alveoli in animal studies. This has led to a better understanding of alveolar physiology. We tested the hypothesis whether a novel handheld videomicroscope could be used for intraoperative detection of alveoli in surgical patients during mechanical ventilation.

MATERIAL/METHODS

Using Sidestream Dark Field imaging, we observed 6 patients (3 adults and 3 children) who underwent elective cardiac surgery. In each patient, the tip of the microscope was placed on the visceral pleural surface of the left upper pulmonary lobe after weaning from cardiopulmonary bypass. The acquired images were converted into digital signals and captured on a computer.

RESULTS

Although cardiac motion artifacts were present, visceral pleural microvascular blood flow could be observed in adults and infants. In infants, sub-pleural cavities (alveoli) were observed. These alveoli were remarkably similar in dimension and structure to those identified previously as true alveoli in animal studies. Quantification of these alveoli demonstrated that mean alveolar diameter, perimeter and area increased with age among the investigated infants (all parameters p<0.001).

CONCLUSIONS

High-quality images of visceral pleural microvessels as well as subpleural cavities, reflecting superficial alveoli, could be obtained in infants. These findings create the opportunity to begin human intervention studies, which should investigate alveolar dynamics during mechanical ventilation in cardio-thoracic surgery in more detail.

Usefulness of intra-aortic balloon pump counterpulsation in patients with cardiogenic shock from acute myocardial infarction

Although intra-aortic balloon pump (IABP) counterpulsation is increasingly being used for the treatment of patients with cardiogenic shock from acute myocardial infarction, data on the long-term outcomes are lacking. The aim of the present study was to evaluate the 30-day and long-term mortality and to identify predictors for 30-day and long-term all-cause mortality of patients with acute myocardial infarction complicated by cardiogenic shock who were treated with IABP. From January 1990 to June 2004, 300 consecutive patients treated with IABP were included. The mean age of the study population was 61 +/- 11 years, and 79% of the patients were men. The survival rate until IABP removal after successful hemodynamic stabilization was 70% (n = 211). The overall cumulative 30-day survival rate was 58%. The 30-day mortality rate decreased over time from 52% in 1990 to 1994 to 36% in 2000 to 2004 (p for trend <0.05). Follow-up ranged from 0 to 15 years. In patients who survived until IABP removal, the cumulative 1-, 5-, and 10-year survival rate was 69%, 58%, and 36%, respectively. The adjusted predictors of long-term mortality were arrhythmias during the intensive cardiac care unit stay (hazard ratio [HR] 1.8, 95% confidence interval [CI] 1.2 to 2.9) and renal failure during the intensive cardiac care unit stay (HR 2.5, 95% CI 1.3 to 5.1). After adjustment, treatment with primary percutaneous coronary intervention (HR 0.5, 95% CI 0.3 to 0.9) and coronary artery bypass grafting (HR 0.4, 95% CI 0.2 to 0.8) were associated with lower long-term mortality. In conclusion, in patients with acute myocardial infarction complicated by cardiogenic shock treated with IABP, the 30-day survival improved with time and an encouraging number of patients survived in the long term.

Dose-dependent benefit of nitroglycerin on microcirculation of patients with severe heart failure

INTRODUCTION

Microcirculatory abnormalities are frequently observed in patients with severe heart failure and correlate to worse outcomes. We tested the hypothesis that nitroglycerin dose-dependently improves perfusion in severe heart failure and that this could be monitored by measuring central-peripheral temperature gradient and with Sidestream Dark Field imaging of the sublingual mucosa.

METHODS

A dose-response study was performed in 17 patients with cardiogenic shock (n = 9) or end-stage chronic heart failure (n = 8) admitted to Erasmus University Medical Center. We did hemodynamic measurements at baseline and during increasing infusion rates of nitroglycerin (up to a maximum dose of 133 microg min(-1)). As parameters of tissue perfusion, we measured central-peripheral temperature gradient (delta-T) and sublingual perfused capillary density (PCD).

RESULTS

Nitroglycerin dose-dependently decreased mean arterial pressure (p < 0.001) and cardiac filling pressures (both central venous pressure (CVP) and pulmonary capillary wedge pressure: p < 0.001). It increased cardiac index (p = 0.01). Nitroglycerin decreased delta-T (p < 0.001) and increased sublingual PCD (p < 0.001). Significant changes in delta-T and PCD occurred earlier, i.e., at a lower doses of NTG, than changes in global hemodynamics. Macrohemodynamic and microcirculatory responses to nitroglycerin infusion were consistent in patients with either cardiogenic shock or end-stage chronic heart failure. Changes in microcirculatory parameters occurred independently of changes in cardiac index.

CONCLUSIONS

Nitroglycerin dose-dependently increases tissue perfusion in patients with severe heart failure, as observed by a decrease in central-peripheral temperature gradient and an increase in sublingual perfused capillary density.