Pulmonary vascular and right ventricular dysfunction in adult critical care: current and emerging options for management: a systematic literature review

Management of Crashing Patients with Pulmonary Hypertension

Critically ill patients with pulmonary hypertension (PH) often seem well, but they can decompensate dramatically in a short time. PH has several causes, classes, and complications; but the natural progression eventually leads to right ventricular failure, which can be extraordinarily difficult to manage. The purpose of this review is to discuss the causes, signs, and symptoms of PH as well as its management strategies and emergent complications. Treatment options are often limited, so it is imperative that the emergency department physician can recognize and manage these patients in a timely fashion.

A rare cause of postoperative hypotension

A 62-year-old woman presented with a 3-month history of abdominal distension and decreased exercise tolerance. A chest radiograph showed a probable left pleural effusion (Fig 1). A CT scan of the abdomen revealed a solid ovarian mass with omental caking and a large volume of ascites; there was also confirmation of a left pleural effusion. Three days before surgery a CT pulmonary angiogram (CTPA) showed no evidence of pulmonary thromboembolism (PTE). The patient had some improvement in her symptoms after paracentesis and thoracentesis with drainage of 2,000 mL and 250 mL of fluid, respectively. She underwent total abdominal hysterectomy, bilateral oophorectomy, and partial sigmoid resection with an estimated blood loss of 850 mL. During the operation, she received 5 L of crystalloid and required phenylephrine at 40 to 80 μg/min to maintain a mean arterial pressure > 65 mm Hg. She was extubated after surgery, but immediately after extubation, she became markedly hypotensive and hypoxemic with a BP of 50/20 mm Hg and an oxygen saturation of 70%. An ECG showed T-wave inversions from V1 to V5 and an S1Q3T3 pattern (Fig 2). A bedside echocardiogram showed an enlarged right ventricle (RV), septal dyskinesia, and obliteration of the left ventricle, all consistent with systolic and diastolic RV overload (Fig 3).

Management of Right Heart Failure in the Intensive Care Unit

Right heart failure is a clinical syndrome of various causes that commonly involves failure of the right ventricle (RV). The hemodynamic hallmark of the syndrome is increasing central venous pressure and worsening cardiac output with a rising RV end-diastolic pressure. When dealing with RV failure, clinicians must assess and optimize the intravascular volume state, support RV contractility, and address any pathologic elevations of afterload so that systemic perfusion is preserved. Despite these measures, there may still be a need to offer rescue interventions to the failing RV in carefully selected patients.

Hybrid ECMO for a patient in respiratory failure developing cardiac insufficiency

A 45-year-old patient in lung failure treated with veno-venous extracorporeal membrane oxygenation (VV ECMO) developed subsequent right heart failure and required cardiac support.

We present a method of upgrading a VV ECMO to a hybrid system for simultaneous support for respiratory and cardiac failure.

Banding the Right Ventricular Assist Device Outflow Conduit: Is It Really Necessary With Current Devices?

Implantable left ventricular assist devices (LVADs) have been adapted clinically for right-sided mechanical circulatory support (RVAD). Previous studies on RVAD support have established the benefits of outflow cannula restriction and rotational speed reduction, and recent literature has focused on assessing either the degree of outflow cannula restriction required to simulate left-sided afterload, or the limitation of RVAD rotational speeds. Anecdotally, the utility of outflow cannula restriction has been questioned, with suggestion that banding may be unnecessary and may be replaced simply by varying the outflow conduit length. Furthermore, many patients have a high pulmonary vascular resistance (PVR) at the time of ventricular assist device (VAD) insertion that reduces with pulmonary vascular bed remodeling. It is therefore important to assess the potential changes in flow through an RVAD as PVR changes. In this in vitro study, we observed the use of dual HeartWare HVAD devices (HeartWare Inc., Framingham, MA, USA) in biventricular support (BiVAD) configuration. We assessed the pumps' ability to maintain hemodynamic stability with and without banding; and with varying outflow cannulae length (20, 40, and 60 cm). Increased length of the outflow conduit was found to produce significantly increased afterload to the device, but this was not found to be necessary to maintain the device within the manufacturer's recommended operational parameters under a simulated normal physiological setting of mild and severe right ventricular (RV) failure. We hypothesize that 40 cm of outflow conduit, laid down along the diaphragm and then up over the RV to reach the pulmonary trunk, will generate sufficient resistance to maintain normal pump function.

Acute right ventricular dysfunction: real-time management with echocardiography

In critically ill patients, the right ventricle is susceptible to dysfunction due to increased afterload, decreased contractility, or alterations in preload. With the increased use of point-of-care ultrasonography and a decline in the use of pulmonary artery catheters, echocardiography can be the ideal tool for evaluation and to guide hemodynamic and respiratory therapy. We review the epidemiology of right ventricular failure in critically ill patients; echocardiographic parameters for evaluating the right ventricle; and the impact of mechanical ventilation, fluid therapy, and vasoactive infusions on the right ventricle. Finally, we summarize the principles of management in the context of right ventricular dysfunction and provide recommendations for echocardiography-guided management.

Pulmonary Hypertension in the Intensive Care Unit

Pulmonary hypertension occurs as the result of disease processes increasing pressure within the pulmonary circulation, eventually leading to right ventricular failure. Patients may become critically ill from complications of pulmonary hypertension and right ventricular failure or may develop pulmonary hypertension as the result of critical illness. Diagnostic testing should evaluate for common causes such as left heart failure, hypoxemic lung disease and pulmonary embolism. Relatively few patients with pulmonary hypertension encountered in clinical practice require specific pharmacologic treatment of pulmonary hypertension targeting the pulmonary vasculature. Management of right ventricular failure involves optimization of preload, maintenance of systemic blood pressure and augmentation of inotropy to restore systemic perfusion. Selected patients may require pharmacologic therapy to reduce right ventricular afterload by directly targeting the pulmonary vasculature, but only after excluding elevated left heart filling pressures and confirming increased pulmonary vascular resistance. Critically-ill patients with pulmonary hypertension remain at high risk of adverse outcomes, requiring a diligent and thoughtful approach to diagnosis and treatment.

Predictors of Prolonged Hemodynamic Compromise After Valve Deployment During Transcatheter Aortic Valve Implantation

OBJECTIVE

To identify the risk factors of prolonged hemodynamic compromise caused by rapid pacing for valve deployment during transcatheter aortic valve implantation.

DESIGN

A retrospective study.

SETTING

Academic hospital.

PARTICIPANTS

Forty-seven patients with severe aortic stenosis who underwent transcatheter aortic valve implantation.

INTERVENTIONS

The time after the end of rapid pacing until systolic arterial pressure and SvO2 recovery (systolic arterial pressure>90 mmHg and SvO2>65%) was defined as "the hemodynamic recovery time" and was measured from online anesthetic charts. The total study population was divided into 2 groups according to the recovery time (third quartile in all patients; 33 and 14 patients in the early and delayed recovery groups, respectively). Subsequently, the factors associated with prolonged hemodynamic compromise after rapid pacing for valve deployment were identified by univariate and multivariate analyses.

MEASUREMENTS AND MAIN RESULTS

Multivariate analysis identified left ventricular end-diastolic diameter (odds ratio, 0.774; 95% confidence interval, 0.608-0.915) and SvO2 (odds ratio, 0.748; 95% confidence interval, 0.590-0.868) as independent factors associated with prolonged hemodynamic compromise after rapid pacing for valve deployment.

CONCLUSIONS

SvO2 and left ventricular end-diastolic diameter were found to be significant independent predictors of prolonged hemodynamic compromise immediately after rapid pacing for valve deployment during transcatheter aortic valve implantation.

Management of acute right ventricular failure in the intensive care unit

Right ventricular (RV) failure occurs when the RV fails to maintain enough blood flow through the pulmonary circulation to achieve adequate left ventricular filling. This can occur suddenly in a previously healthy heart due to massive pulmonary embolism or right-sided myocardial infarction, but many cases encountered in the intensive care unit involve worsening of compensated RV failure in the setting of chronic heart and lung disease. Management of RV failure is directed at optimizing right-sided filling pressures and reducing afterload. Due to a lower level of vascular tone, vasoactive medications have less salient effects on reducing vascular resistance in the pulmonary than in the systemic circulation. Successful management requires reversal of any conditions that heighten pulmonary vascular tone and the use of selective pulmonary vasodilators at doses that do not induce systemic hypotension or worsening of oxygenation. Systemic systolic arterial pressure should be kept close to RV systolic pressure to maintain RV perfusion. When these efforts fail, the judicious use of inotropic agents may help improve RV contractility enough to maintain cardiac output. Extracorporeal life support is increasingly being used to support patients with acute RV failure who fail to respond to medical management while the underlying cause of their RV failure is addressed.

Acute effects of levosimendan in experimental models of right ventricular hypertrophy and failure

Pulmonary arterial hypertension (PAH) is a fatal disease, and the ultimate cause of death is right ventricular (RV) failure. In this study, we investigated the acute hemodynamic effects of levosimendan in two rat models of RV hypertrophy and failure. Wistar rats were randomized to receive sham surgery (n = 8), pulmonary trunk banding (PTB; n = 8), or monocrotaline injection (MCT; n = 7). RV function was evaluated at baseline and after injection of placebo and two concentrations of levosimendan (12 and 60 μg/kg) using magnetic resonance imaging, echocardiography, and invasive pressure recordings. PTB and MCT injection caused hypertrophy, dilatation, and failure of the RV compared with sham surgery. Levosimendan increased RV end systolic pressure (sham surgery: 16.0% ± 3.8% [P = 0.0038]; MCT: 9.9% ± 3.1% [P = 0.018]; PTB: 24.5% ± 3.3% [P = 0.0001]; mean ± SEM) compared with placebo. Levosimendan markedly increased RV stroke volume (SV) in the MCT group (29.1% ± 8.3%; P = 0.012), did not change RV SV in the PTB group (0.4% ± 4.5%; P = 0.93), and decreased RV SV in the sham surgery group (-10.9% ± 3.7%; P = 0.020). Nitroprusside, which was used to mimic the systemic arterial vasodilator action of levosimendan, did not influence RV function. These data demonstrate that levosimendan acutely improves the failing right heart in a MCT model of PAH and that the mechanism involves a direct acute positive inotropic effect on the hypertrophic and failing RV of the rat.

Hydraulic and hemodynamic performance of a minimally invasive intra-arterial right ventricular assist device

Right ventricular assistance is still in the early phase of development compared to left ventricular assist device (LVAD) technology. In order to provide flexible pulmonary support and potentially reduce the known complications, we propose a minimally invasive right ventricular assist device (MIRVAD), located in the pulmonary artery (PA) and operating in series with the right ventricle (RV). The MIRVAD is an intra-arterial rotary blood pump containing a single axial impeller, which is not enclosed by a rigid housing but stent-fixed within the vessel. The impeller geometry has been designed with the assistance of analytical methods and computational fluid dynamics (CFD). The hydraulic performance of the impeller was evaluated experimentally with a customized test setup using blood synthetic medium (HES). The blade-tip clearance (BTC) was varied between 0.25-4.25 mm to evaluate the effect of different PA sizes on impeller performance. Furthermore, the Langrangian particle-tracking method was used to estimate the level of hemolysis and generate numerical blood damage indexes.The impeller design generated 25.6 mmHg for flow rates of 5 lpm at a speed of 6,000 rpm at the baseline condition, capable of providing sufficient support for the RV. The BTC presented a significant effect on the static pressure generation and the efficiency, but the operational range is suitable for most vessel sizes. The numerical results demonstrated a low risk of blood damage at the design point (mean Lagrangian damage index 2.6*10(-7)). The preliminary results have encouraged further impeller optimization and development of the MIRVAD.

Perioperative management of pulmonary hypertension during lung transplantation (a lesson for other anaesthesia settings)

Patients with pulmonary hypertension are some of the most challenging for an anaesthesiologist to manage. Pulmonary hypertension in patients undergoing surgical procedures is associated with high morbidity and mortality due to right ventricular failure, arrhythmias and ischaemia leading to haemodynamic instability. Lung transplantation is the only therapeutic option for end-stage lung disease. Patients undergoing lung transplantation present a variety of challenges for anaesthesia team, but pulmonary hypertension remains the most important. The purpose of this article is to review the anaesthetic management of pulmonary hypertension during lung transplantation, with particular emphasis on the choice of anaesthesia, pulmonary vasodilator therapy, inotropic and vasopressor therapy, and the most recent intraoperative monitoring recommendations to optimize patient care.

Current clinical management of pulmonary arterial hypertension

During the past 2 decades, there has been a tremendous evolution in the evaluation and care of patients with pulmonary arterial hypertension (PAH). The introduction of targeted PAH therapy consisting of prostacyclin and its analogs, endothelin antagonists, phosphodiesterase-5 inhibitors, and now a soluble guanylate cyclase activator have increased therapeutic options and potentially reduced morbidity and mortality; yet, none of the current therapies have been curative. Current clinical management of PAH has become more complex given the focus on early diagnosis, an increased number of available therapeutics within each mechanistic class, and the emergence of clinically challenging scenarios such as perioperative care. Efforts to standardize the clinical care of patients with PAH have led to the formation of multidisciplinary PAH tertiary care programs that strive to offer medical care based on peer-reviewed evidence-based, and expert consensus guidelines. Furthermore, these tertiary PAH centers often support clinical and basic science research programs to gain novel insights into the pathogenesis of PAH with the goal to improve the clinical management of this devastating disease. In this article, we discuss the clinical approach and management of PAH from the perspective of a single US-based academic institution. We provide an overview of currently available clinical guidelines and offer some insight into how we approach current controversies in clinical management of certain patient subsets. We conclude with an overview of our program structure and a perspective on research and the role of a tertiary PAH center in contributing new knowledge to the field.

Pulmonary arterial hypertension in pregnancy

Pulmonary hypertension is a medical condition characterized by elevated pulmonary arterial pressure and secondary right heart failure. Pulmonary arterial hypertension is a subset of pulmonary hypertension, which is characterized by an underlying disorder of the pulmonary arterial vasculature. Pulmonary hypertension can also occur secondarily to structural cardiac disease, autoimmune disorders, and toxic exposures. Although pregnancies affected by pulmonary hypertension and pulmonary arterial hypertension are rare, the pathophysiology exacerbated by pregnancy confers both high maternal and fetal mortality and morbidity. In light of new treatment modalities and the use of a multidisciplinary approach to care, maternal outcomes may be improving.

CRITICAL CARE ECHO ROUNDS: Haemodynamic instability

The use of echocardiography, whilst well established in cardiology, is a relatively new concept in critical care medicine. However, in recent years echocardiography's potential as both a diagnostic tool and a form of advanced monitoring in the critically ill patient has been increasingly recognised. In this series of Critical Care Echo Rounds, we explore the role of echocardiography in critical illness, beginning here with haemodynamic instability. We discuss the pathophysiology of the shock state, the techniques available to manage haemodynamic compromise, and the unique role which echocardiography plays in this complex process.

Perioperative management of the patient with pulmonary hypertension

Patients with pulmonary hypertension are at increased risk for perioperative morbidity and mortality. Elective surgery is generally discouraged in this patient population; however, there are times when surgery is deemed necessary. Currently, there are no guidelines for the preoperative risk assessment or perioperative management of subjects with pulmonary hypertension. The majority of the literature evaluating perioperative risk factors and mortality rates is observational and includes subjects with multiple etiologies of pulmonary hypertension. Subjects with pulmonary arterial hypertension, also referred to as World Health Organization group I pulmonary hypertension, and particularly those receiving pulmonary arterial hypertension-specific therapy may be at increased risk. Perioperative management of these patients requires a solid understanding and careful consideration of the hemodynamic effects of anesthetic agents, positive pressure ventilation and volume shifts associated with surgery in order to prevent acute right ventricular failure. We reviewed the most recent data regarding perioperative morbidity and mortality for subjects with pulmonary hypertension in an effort to better guide preoperative risk assessment and perioperative management by a multidisciplinary team.

[Management of patients with pulmonary hypertension]

Due to the increased survival of patients with pulmonary hypertension, even non-cardiac anesthesiologists will see these patients more frequently for anesthesia. The hemodynamic goal in the perioperative period is to avoid an increase in pulmonary vascular resistance (PVR) and to reduce a possibly pre-existing elevated PVR. Acute increases of chronically elevated PVR may result from hypoxia, hypercapnia, acidosis, hypothermia, elevated sympathetic output and also release of endogenous or application of exogenous pulmonary vasoconstrictors. Early recognition and treatment of these changes might be life saving in these patients. Drug interventions to perioperatively reduce PVR include administration of pulmonary vasodilators, such as oxygen, prostacyclines (epoprostenol, iloprost), phosphodiesterase III (milrinone) and V (sildenafil) inhibitors, as well as nitrates and nitric oxide. Along with the concept of selective pulmonary vasodilation inhalative administration of pulmonary vasodilators has benefits compared to intravenous administration. New therapeutic strategies, such as inhalational iloprost, inhalational milrinone and intravenous sildenafil can be introduced without significant technical support even in smaller departments.

Anaesthetic consideration during laparoscopic bilateral simultaneous nephrectomy

STUDY OBJECTIVE:

To assess outcome from anaesthesia during laparoscopic bilateral simultaneous nephrectomy.

DESIGN:

Retrospective study.

MEASUREMENTS:

Preoperative Hb%, serum potassium, coagulation profile electrocardiography (ECG) changes, 2D Echography, x-ray chest, haemodynamic changes, end-tidal carbon dioxide (EtCO₂), fluid management and postoperative analgesia.

RESULTS:

The mean age was 24.75 ± 14.35 years. The mean duration of surgery was 120 ± 80 minutes. The Hb%, serum creatinine and serum potassium were 9.4 ± 1.04%, 6.79 ± 4.91 meq/L and 3.61 ± 0.51 meq/L, respectively. Pulse rate mean blood pressure and EtCO₂ were recorded after creation of pneumoperitoneum and at 15, 30, 45 and after exsufflation of pneumoperitoneum. After pneumoperitoneum, there was increase in pulse rate, systolic blood pressure, diastolic blood pressure and EtCO₂. After 30 minutes and throughout the surgery, these variables remained stable. Four patients required nitroglycerine infusion for intraoperative hypertention. Only one patient required packed cell volume (PCV) transfusion and total intravenous fluid was 1 ± 0.5 L. At the time of exsufflation, there was decrease in pulse rate, systolic and diastolic blood pressure and EtCO₂.

CONCLUSION:

Because of advancement in anaesthetic agents and muscle relaxant, there is safe outcome from anaesthesia during laparoscopic bilateral simultaneous nephrectomy.

Age dependency of vasopressin pulmonary vasodilatory effect in rats

BACKGROUND

Vasopressin is a systemic vasoconstrictor. Its pulmonary vasodilatory effect is controversial, and limited data are available on its use in neonates with pulmonary hypertension. Hypothesizing that the vasopressin-induced pulmonary vasodilation is developmentally regulated, we evaluated its pulmonary and systemic arterial response in newborn and adult rats.

METHODS

Vessels were mounted on a wire myograph, and the vasopressin-induced changes in vasomotor tone measured. The vessel- and age-dependent differences in vasopressin V1a and V2 receptors' expression were evaluated by western blotting.

RESULTS

Vasopressin induced a dose-dependent increase in mesenteric arterial tone at both ages, but of greater magnitude in adult vessels (P < 0.01). At lower concentrations, vasopressin induced pulmonary vasodilation in adult vessels and vasoconstriction in newborn arteries. The adult vasopressin-induced pulmonary vasodilation was inhibited by ibuprofen, suggesting that the response is prostaglandin mediated. Pulmonary tissue V1a receptor protein expression was higher in adult, when compared with newborn arteries (P < 0.01). The adult vessels V1a expression predominated in the pulmonary arteries, and V2 was only detected in mesenteric arteries.

CONCLUSION

The vasopressin-induced pulmonary vasodilation is absent in newborn rats likely due to the lower tissue V1a expression early in life. These animal data challenge the therapeutic use of vasopressin in neonatal pulmonary hypertension.

Milrinone relaxes pulmonary veins in guinea pigs and humans

Introduction

The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH). However, its action on pulmonary veins (PVs) is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs) and humans.

Material and Methods

Precision-cut lung slices (PCLS) were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ET_A-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL).

Results

In the IPL (GP), milrinone (10 µM) lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP), milrinone relaxed naïve and pre-constricted PVs (120%) and this relaxation was attenuated by inhibition of protein kinase G (KT 5823), adenyl cyclase (SQ 22536) and protein kinase A (KT 5720), but not by inhibition of NO-synthesis (L-NAME). In addition, milrinone-induced relaxation was dependent on the activation of K_ATP-, BK_Ca²⁺- and K_v-channels. Human PVs also relaxed to milrinone (121%), however only if pre-constricted.

Discussion

Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on K_ATP-, BK_Ca²⁺- and K_v-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.

Inotropic agents and vasodilator strategies for acute myocardial infarction complicated by cardiogenic shock or low cardiac output syndrome

BACKGROUND

The recently published German-Austrian S3 Guideline for the treatment of infarct related cardiogenic shock (CS) revealed a lack of evidence for all recommended therapeutic measures.

OBJECTIVES

To determine the effects in terms of efficacy, efficiency and safety of cardiac care with inotropic agents and vasodilator strategies versus placebo or against each other for haemodynamic stabilisation following surgical treatment, interventional therapy (angioplasty, stent implantation) and conservative treatment (that is no revascularization) on mortality and morbidity in patients with acute myocardial infarction (AMI) complicated by CS or low cardiac output syndrome (LCOS).

SEARCH METHODS

We searched CENTRAL, MEDLINE (Ovid), EMBASE (Ovid) and ISI Web of Science, registers of ongoing trials and proceedings of conferences in January 2013. Reference lists were scanned and experts in the field were contacted to obtain further information. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials in patients with AMI complicated by CS or LCOS.

DATA COLLECTION AND ANALYSIS

Data collection and analysis were performed according to the published protocol. All trials were analysed individually. Hazard ratios (HRs) and odds ratios with 95% confidence intervals (CI) were extracted but not pooled because of high heterogeneity between the control group interventions.

MAIN RESULTS

Four eligible, very small studies were identified from a total of 4065 references. Three trials with high overall risk of bias compared levosimendan to standard treatment (enoximone or dobutamine) or placebo. Data from a total of 63 participants were included in our comparisons, 31 were treated with levosimendan and 32 served as controls. Levosimendan showed an imprecise survival benefit in comparison with enoximone based on a very small trial with 32 participants (HR 0.33; 95% CI 0.11 to 0.97). Results from the other similarly small trials were too imprecise to provide any meaningful information about the effect of levosimendan in comparison with dobutamine or placebo. Only small differences in haemodynamics, length of hospital stay and the frequency of major adverse cardiac events or adverse events overall were found between study groups.Only one small randomised controlled trial with three participants was found for vasodilator strategies (nitric oxide gas versus placebo) in AMI complicated by CS or LCOS. This study was too small to draw any conclusions on the effects on our key outcomes.

AUTHORS' CONCLUSIONS

At present there are no robust and convincing data to support a distinct inotropic or vasodilator drug based therapy as a superior solution to reduce mortality in haemodynamically unstable patients with CS or low cardiac output complicating AMI.

Acute right heart syndrome in the critically ill patient

Acute right heart syndrome is a sudden deterioration in right ventricular performance, resulting in right ventricular failure and confers significant in-hospital morbidity and mortality. In critically ill patients, the syndrome is often undiagnosed and untreated, as these patients do not usually exhibit the common clinical manifestations of the condition, making the diagnosis challenging for the intensivist. In this narrative review we focus on the pathophysiology of acute right heart syndrome, in critical illness, diagnostic modalities used to assess right ventricular function and management of acute right heart syndrome, including mechanical ventilation strategies and circulatory support.

Pulmonary Arterial Hypertension in Intensive Care Unit

For the intensive care unit (ICU) physician, the diagnosis of pulmonary arterial hypertension (PAH) is difficult as it can easily be confounded with other forms of pulmonary hypertension (PH). The key issue is that PAH is a form of PH. On the opposite, PH does not automatically imply PAH. Pulmonary arterial hypertension must be differentiated from other causes of PH that are frequently seen in ICU. It was recently emphasized that pulmonary veno-occlusive disease (PVOD) must be differentiated from PH and PAH. The prognosis of PAH was consistently improved in the ten past years by introduction of selective pulmonary vasodilators and management by highly specialized medical teams. In ICU patients, PAH remains a severe disease with a high mortality rate. When PAH is suspected, a systematic diagnosis approach is of particular importance in order to rapidly eliminate left cardiac, thromboembolic and pulmonary causes of PH. Left cardiac disease is the most common cause of PH. Early recognition of PAH allows a rapid introduction of selective pulmonary vasodilators that can improve outcome. Idiopathic PAH is the most frequent cause but it can also be associated with scleroderma, HIV infection, anorexigen toxicity, thyroid disease, cirrhosis. Pulmonary vasodilators should be only a part of a general management including treatment of triggering factors, optimization of fluid balance, decrease of RV afterload by using pulmonary vasodilators while maintaining cardiac output and mean arterial pressure. The early contact of PH referral center or specialized physician is of particular importance.

[Nitrid oxide, levosimendan and sildenafile in a patient with right ventricle dysfunction and severe pulmonary hypertension after cardiac surgery]

Pulmonary hypertension (PHT) and the resulting right ventricle dysfunction are important risk factors in patients who undergo cardiac surgery. The treatment of PHT and right ventricle dysfunction should be focused on maintaining the correct right ventricle after load, improving right ventricle function and reducing the right ventricle pre-load and therefore reducing pulmonary vascular resistance by means of vasodilators. A combined therapy of vasodilators and medicines which have different mechanisms of action, is becoming an option for the treatment of PHT. We present a 65 year old woman that suffered from mitral regurgitation, aortic valve disease, tricuspid and ascending aortic dilation with 115mmHg of pulmonary artery pressure (by ultrasound evaluation). The patient was operated on of mitral, aortic valve and tricuspid plastia and proximal aortic artery plastia as well. Previosly to surgery the patient suffered right ventricle dysfunction and PHT and was treated with nitric oxide, intravenous sildenafil and levosimendan. Subsequent evolution was satisfactory, PHT being controlled, without arterial hypotension nor respiratory alterations.

Management of pulmonary arterial hypertension during pregnancy: a retrospective, multicenter experience

BACKGROUND

Pulmonary arterial hypertension (PAH) is a rare disease with a predilection for young women that is associated with right ventricular failure and premature death. PAH can complicate pregnancy with hemodynamic instability or sudden death during parturition and postpartum. Our aim was to examine the impact of PAH on pregnancy outcomes in the modern era.

METHODS

We conducted a retrospective evaluation of pregnant patients with PAH managed between 1999 and 2009 at five US medical centers. Patient demographics, medical therapies, hemodynamic measurements, manner of delivery, anesthetic administration, and outcomes were assessed.

RESULTS

Among 18 patients with PAH, 12 continued pregnancy and six underwent pregnancy termination. Right ventricular systolic pressure in patients managed to parturition was 82 ± 5 mm Hg and in patients with pregnancy termination was 90 ± 16 mm Hg. Six patients underwent pregnancy termination at mean gestational age of 13 ± 1.0 weeks with no maternal deaths or complications. Twelve patients elected to continue their pregnancy and were hospitalized at 29 ± 1.4 weeks. PAH-specific therapy was administered to nine (75%) at time of delivery consisting of sildenafil, IV prostanoids, or combination therapy. All parturients underwent Cesarean section at 34 weeks with one in-hospital death and one additional death 2 months postpartum for maternal mortality of 16.7%.

CONCLUSIONS

Compared with earlier reports, maternal morbidity and mortality among pregnant women with PAH was reduced, yet maternal complications remain significant and patients should continue to be counseled to avoid pregnancy.

[Intensive care management of critically ill adults with congenital heart disease]

Due to improvements in cardiac surgery and perioperative care the number of adults with congenital heart disease is continuously growing. The perioperative and intensive care management of these patients is a challenge due to the variety of pathologies and surgical options as well as the complex pathophysiology. Many patients develop organ dysfunction with time and many require multiple cardiac operations as well as non-cardiac interventions during adulthood. While these patients are best treated in dedicated tertiary centers that provide a multidisciplinary expertise, basic knowledge of this population is important for everyone involved in acute medical care. This review will discuss some general aspects of adults with congenital heart disease such as pulmonary hypertension, Eisenmenger syndrome, cyanosis, pregnancy and perioperative care, with a special focus on the management of critically ill patients.

Massive pulmonary embolism

Massive pulmonary embolism (PE) is a potentially lethal condition, with death usually caused by right ventricular (RV) failure and cardiogenic shock. Systemic thrombolysis (unless contraindicated) is recommended as the first-line treatment of massive PE to decrease the thromboembolic burden on the RV and increase pulmonary perfusion. Surgical pulmonary embolectomy or catheter-directed thrombectomy should be considered in patients with contraindications to fibrinolysis, or those with persistent hemodynamic compromise or RV dysfunction despite fibrinolytic therapy. Critical care management predominantly involves supporting the RV, by optimizing preload, RV contractility, and coronary perfusion pressure and minimizing afterload. Despite these interventions, mortality remains high.

Assessment of changes in cardiac index and fluid responsiveness: a comparison of Nexfin and transpulmonary thermodilution

BACKGROUND

The Nexfin device uses non-invasive photoplethysmography to monitor cardiac output and respiratory variations in pulse pressure and stroke volume. The aim of this study was to compare rapid changes in cardiac index after fluid challenge between Nexfin and bolus transpulmonary thermodilution and the ability to predict fluid responsiveness of dynamic indices given by Nexfin.

METHODS

Simultaneous comparative cardiac index were collected from transpulmonary thermodilution and Nexfin before and after fluid challenge in 45 patients following conventional cardiac surgery. Correlations, Bland-Altman analyses and percentage errors were calculated. Pulse pressure variations and stroke volume variations before fluid challenge were collected to assess their discrimination in predicting fluid responsiveness.

RESULTS

Eight (18%) patients were excluded. A weak positive relationship was found between rapid changes in cardiac index after fluid challenge given by both technologies (n = 37, r = 0.39, P = 0.019). Bias, precision and limits of agreements were 0.20 l/min/m(2) (95% confidence interval (CI) 0.02-0.40), 0.57 l/min/m(2) and ± 1.12 l/min/m(2) before fluid challenge, and 0.01 l/min/m(2) (95% CI -0.24 to 0.26), 0.74 l/min/m(2) and ± 1.45 l/min/m(2) after fluid challenge. Percentage errors between Nexfin and transpulmonary thermodilution were 55% and 58% before and after fluid challenge, respectively. Pulse pressure variations and stroke volume variations given by Nexfin were not discriminant to predict fluid responsiveness: areas under receiver operating characteristics curves 0.57 (95% CI 0.40-0.73) and 0.50 (0.33-0.67), respectively.

CONCLUSIONS

The Nexfin cannot be used to measure rapid changes in cardiac index following fluid challenge and to predict fluid responsiveness after cardiac surgery.

Forgotten driving forces in right heart failure (Part II): experimental study

BACKGROUND

Cardiac-assist devices for right ventricular failure remain controversial with poor results. This study evaluated a pulsatile cardiac-assist device in an acute right ventricular failure model vs. current therapies.

MATERIALS AND METHODS

Pulmonary regurgitation was created in 12 piglets by valve avulsion and external transfixation of 2 pulmonary artery cusps suspended to the pulmonary arterial wall. The piglets were divided into 2 treatment groups: a pulsatile group P and a non-pulsatile group NP. Management started when severe right ventricular failure was observed (48.1 ± 24.5 min). In group P, pulsatile trousers driven by a pneumatic generator were pulsated intermittently at 40 beats min(-1). Group NP was treated with oral tadalafil 1 mg kg(-1), intravenous fluids, and adrenaline 0.3 μg kg(-1). After 1 h of therapy, cardiac output was significantly better in group P than group NP (1 ± 0.2 vs. 0.7 ± 0.2 L min(-1)). Mean right ventricular pressure (16 ± 6 vs. 24 ± 2 mm Hg) and pulmonary arterial pressure (22 ± 1 vs. 31 ± 2 mm Hg) were lower in group P. Vascular resistances indices were lower in group P than group NP: pulmonary resistance index was 174 ± 60 vs. 352 ± 118 dyne sec cm(-5)kg(-1); systemic resistance index was 611 ± 70 vs. 1215 ± 315 dyne sec cm(-5)kg(-1). Western-blot analysis showed higher endogenous NO synthase expression in group P pulmonary arteries.

CONCLUSIONS

The pulsatile suit can be used safely as a noninvasive cardiac-assist device in acute right ventricular failure. This represents a cost-effective nearly physiological method, suitable for adults and children.

Carbonic anhydrase IX in the prediction of right ventricular dysfunction in patients with hemodynamically stable acute pulmonary embolism

Right ventricular dysfunction (RVD) defined by echocardiography and/or by natriuretic peptides is a well-known predictor of prognosis in patients with pulmonary embolism (PE). This study investigated carbonic anhydrase IX (CA IX) levels for predicting echocardiographic RVD in patients with PE. A total of 150 normotensive patients with PE were included. The levels of CA IX, N-terminal pro-brain-type natriuretic peptide (NT-proBNP), and high-sensitive cardiac troponin T were significantly elevated in patients with PE with RVD on echocardiography. A receiver-operating characteristic curve analysis showed a value of 0.751 for CA IX, 0.714 for NT-proBNP, and 0.650 for high-sensitive troponin-T to predict RVD on echocardiography. The cutoff value to predict RVD was 32.45 pg/mL for CA IX (sensitivity: 89.3% and specificity: 51.1%). There was a significant positive correlation between the CA IX level and the systolic pulmonary arterial pressure on echocardiography (ρ = .21; P = .035). The CA IX is a significant serologic predictor of RVD in acute PE and correlates with systolic pulmonary arterial pressure.

Unexpected and fatal hemodynamic collapse during transapical transcatheter aortic valve implantation -A case report-

Although transcatheter aortic valve implantation (TAVI) is generally accepted as an alternative or promising treatment option for patients with decompensated cardiovascular disease in an inoperable or high-risk condition, severe hypotension and/or arrhythmia associated with rapid ventricular pacing still poses a challenge to many clinicians. This report describes a 79-year-old patient who experienced fatal hemodynamic collapse, which suddenly developed after a rapid ventricular pacing in spite of pre-administration of vasopressor. The procedure and anesthesia were uneventful until the first rapid ventricular pacing was applied. Following rapid ventricular pacing, his cardiovascular state was severely compromised and could not be recovered. Despite early initiation of extracorporeal membrane oxygenation device and supportive care, he died from heart failure on post-procedure day four.

Inhaled PLGA particles of prostaglandin E₁ ameliorate symptoms and progression of pulmonary hypertension at a reduced dosing frequency

This study sought to investigate the efficacy of a noninvasive and long acting polymeric particle based formulation of prostaglandin E1 (PGE1), a potent pulmonary vasodilator, in alleviating the signs of pulmonary hypertension (PH) and reversing the biochemical changes that occur in the diseased lungs. PH rats, developed by a single subcutaneous injection of monocrotaline (MCT), were treated with two types of polymeric particles of PGE1, porous and nonporous, and intratracheal or intravenous plain PGE1. For chronic studies, rats received either intratracheal porous poly(lactic-co-glycolic acid) (PLGA) particles, once- or thrice-a-day, or plain PGE1 thrice-a-day for 10 days administered intratracheally or intravenously. The influence of formulations on disease progression was studied by measuring the mean pulmonary arterial pressure (MPAP), evaluating right ventricular hypertrophy and assessing various molecular and cellular makers including the degree of muscularization, platelet aggregation, matrix metalloproteinase-2 (MMP-2), and proliferating cell nuclear antigen (PCNA). Both plain PGE1 and large porous particles of PGE1 reduced MPAP and right ventricular hypertrophy (RVH) in rats that received the treatments for 10 days. Polymeric porous particles of PGE1 produced the same effects at a reduced dosing frequency compared to plain PGE1 and caused minimal off-target effects on systemic hemodynamics. Microscopic and immunohistochemical studies revealed that porous particles of PGE1 also reduced the degree of muscularization, von Willebrand factor (vWF), and PCNA expression in the lungs of PH rats. Overall, our study suggests that PGE1 loaded inhalable particulate formulations improve PH symptoms and arrest the progression of disease at a reduced dosing frequency compared to plain PGE1.