A standardized definition for right ventricular failure in cardiac surgery patients

Continuous Right Ventricular Pressure Monitoring in Cardiac Surgery

OBJECTIVE

Right ventricular (RV) dysfunction in cardiac surgery can lead to RV failure, which is associated with increased morbidity and mortality. Abnormal RV function can be identified using RV pressure monitoring. The primary objective of the study is to determine the proportion of patients with abnormal RV early to end-diastole diastolic pressure gradient (RVDPG) and abnormal RV end-diastolic pressure (RVEDP) before initiation and after cardiopulmonary bypass (CPB) separation. The secondary objective is to evaluate if RVDPG before CPB initiation is associated with difficult and complex separation from CPB, RV dysfunction, and failure at the end of cardiac surgery.

DESIGN

Prospective study.

SETTING

Tertiary care cardiac institute.

PARTICIPANTS

Cardiac surgical patients.

INTERVENTION

Cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

Automated electronic quantification of RVDPG and RVEDP were obtained. Hemodynamic measurements were correlated with cardiac and extracardiac parameters from transesophageal echocardiography and postoperative complications. Abnormal RVDPG was present in 80% of the patients (n = 105) at baseline, with a mean RVEDP of 14.2 ± 3.9 mmHg. Patients experienced an RVDPG > 4 mmHg for a median duration of 50.2% of the intraoperative period before CPB initiation and 60.6% after CPB separation. A total of 46 (43.8%) patients had difficult/complex separation from CPB, 18 (38.3%) patients had RV dysfunction, and 8 (17%) had RV failure. Abnormal RVDPG before CPB was not associated with postoperative outcome.

CONCLUSION

Elevated RVDPG and RVEDP are common in cardiac surgery. RVDPG and RVEDP before CPB initiation are not associated with RV dysfunction and failure but can be used to diagnose them.

Possible role of QRS duration in the right ventricle as a perioperative monitoring parameter for right ventricular function: a prospective cohort analysis in robotic mitral valve surgery

Background

The clinical importance of the right ventricle (RV) has recently been recognized; however, assessing its function during cardiac surgery remains challenging owing to its complex anatomy. A temporary transvenous pacing catheter is a useful tool in the small surgical field of minimally invasive cardiac surgery, and an electrocardiogram recorded through the catheter is composed of the direct electrophysiological activity of the RV. Therefore, we hypothesized that QRS duration in the RV (QRSRV) could be a useful monitoring parameter for perioperative RV function.

Methods

We conducted a prospective cohort analysis involving adult patients undergoing robotic mitral valve repair. A bipolar pacing catheter was inserted using x-ray fluoroscopy, and the QRSRV duration was assessed at four time points: preoperative baseline, during one-lung ventilation, after weaning from cardiopulmonary bypass, and before the end of surgery. At the same time points, right ventricular fractional area change (RVFAC) measured by transesophageal echocardiography and QRS duration at V5 lead of the body surface electrocardiogram (QRSV5) were also evaluated.

Results

In the 94 patients analyzed, QRSRV duration was significantly prolonged during robotic mitral valve repair (p = 0.0009), whereas no significant intraoperative changes in RVFAC were observed (p = 0.2). By contrast, QRSV5 duration was significantly shortened during surgery (p < 0.00001). Multilinear regression showed a significant correlation of QRSRV duration with RVFAC (p = 0.00006), but not with central venous pressure (p = 0.9), or left ventricular ejection fraction (p = 0.3). When patients were divided into two groups by postoperative QRSRV > 100 or ≤100 ms, 25 patients (26.6%) exhibited the prolonged QRSRV duration, and the mean increase in the postoperative QRSRV from preoperative baseline was 12 ms (p = 0.001), which was only 0.6 ms in patients with QRSRV ≤ 100 ms (p = 0.6). Cox regression analysis showed that prolonged postoperative QRSRV duration was the only significant parameter associated with a longer ICU stay after surgery (p = 0.02; hazard ratio, 0.55).

Conclusion

Our data suggest that QRSRV duration is a useful parameter for monitoring the RV during cardiac surgery, possibly better than a commonly used echocardiographic parameter, RVFAC. An electrophysiological assessment by QRSRV duration could be a practical tool for the complex anatomy of the RV, especially with limited modalities in perioperative settings.

Balloon atrial septostomy: a weapon to challenge right heart failure after cardiac surgery

Right heart failure is a common complication after cardiac surgery, and its mortality remains high. The medical management and veno-arterial extracorporeal membrane oxygenation has shown significant improvement in the majority of cases. However, a minority of patients may still require long-term mechanical circulatory support or heart transplantation. Balloon atrial septostomy is a new method for the prevention and treatment of right heart failure, which may avoid the patient's dependence on mechanical circulatory support. We used this method to try to treat patients with right heart failure after cardiac surgery, and all received good benefits. Therefore, we selected several representative cases to report, in order to guide other qualified cardiac surgeons to carry out relevant clinical practice.

Preoperative right ventricular strain as an early predictor of perioperative cardiac failure in patients undergoing mitral surgery: An exploratory study

Objectives

This study's primary purpose was to demonstrate the correlation of preoperative right ventricular free-wall longitudinal strain (RVFWLS) and pre-/postsurgical variation in strain (delta strain) with the clinical and echocardiographic diagnosis of right ventricular dysfunction. Its secondary purpose was to determine the correlation of RVFWLS and delta strain with length of stay (LOS) in the intensive care unit (ICU), ventilation days, trend of natriuretic peptide test. (NT-proBNP) and lactate in the first 48 h, incidence of acute renal failure, and 28-day mortality.

Design

Prospective observational study.

Setting

Cardio-thoracic and Vascular Anaesthesia Department and ICU of the University Hospital Integrated Trust of Verona.

Participants

Patients scheduled for mitral surgery.

Interventions

None.

Measurements and Main Results

All clinical and transoesophageal echocardiographic (TEE) parameters were collected at baseline, before surgery (T1) and at admission in the ICU postsurgery (T2). During the postoperative period, the clinical and echocardiographic diagnoses of right, left, or biventricular dysfunction were evaluated. TEE parameters were evaluated by a cardiologist offline. The patients were divided into two subgroups according to the development of any type of ventricular dysfunction. No statistically significant differences emerged between the two groups. According to a logistic regression model, a T1-RVFWLS value of -15% appeared to predict biventricular dysfunction (sensitivity: 100%; specificity: 91.3%). No correlation between T1- or T2-RVFWLS and creatinine, hours of ventilation or ICU LOS was found.

Conclusions

Our study introduces a new parameter that could be used in perioperative evaluations to identify patients at risk of postoperative biventricular dysfunction.

Isoproterenol improves hemodynamics and right ventricle-pulmonary artery coupling after heart transplantation

Right ventricular failure (RVF) is a major cause of early mortality after heart transplantation (HT). Isoproterenol (Iso) has chronotropic, inotropic, and vasodilatory properties, which might improve right ventricle function in this setting. We aimed to investigate the hemodynamic effects of isoproterenol on patients with post-HT RVF. We conducted a 1-yr retrospective observational study including patients receiving isoproterenol (Iso) and dobutamine for early RVF after HT. A comprehensive multiparametric hemodynamic evaluation was performed successively three times: no isoproterenol, low doses: 0.025 µg/kg/min, and high doses: 0.05 µg/kg/min (henceforth, respectively, called no Iso, low Iso, and high Iso). From June 2022 to June 2023, 25 patients, median [interquartile range (IQR) 25-75] age 54 [38-61] yr, were included. Before isoproterenol was introduced, all patients received dobutamine, and 15 (60%) were on venoarterial extracorporeal membrane oxygenation (VA-ECMO). Isoproterenol significantly increased heart rate from 84 [77-99] (no Iso) to 91 [88-106] (low Iso) and 102 [90-122] beats/min (high Iso, P < 0.001). Similarly, cardiac index rose from 2.3 [1.4-3.1] to 2.7 [1.8-3.4] and 3 [1.9-3.7] L/min/m2 (P < 0.001) with a concomitant increase in indexed stroke volume (28 [17-34] to 31 [20-34] and 33 [23-35] mL/m2, P < 0.05). Effective pulmonary arterial elastance and pressures were not modified by isoproterenol. Pulmonary vascular resistance (PVR) tended to decrease from 2.9 [1.4-3.6] to 2.3 [1.3-3.5] wood units (WU), P = 0.06. Right ventricular ejection fraction/systolic pulmonary artery pressure (sPAP) evaluating right ventricle-pulmonary artery (RV-PA) coupling increased after isoproterenol from 0.8 to 0.9 and 1%·mmHg-1 (P = 0.001). In conclusion, in post-HT RVF, isoproterenol exhibits chronotropic and inotropic effects, thereby improving RV-PA coupling and resulting in a clinically relevant increase in the cardiac index.NEW & NOTEWORTHY This study offers a detailed and comprehensive hemodynamic investigation at the bedside, illustrating the favorable impact of isoproterenol on right ventricular-pulmonary arterial coupling and global hemodynamics. It elucidates the physiological effects of an underused inotropic strategy in a critical clinical scenario. By enhancing cardiac hemodynamics, isoproterenol has the potential to expedite right ventricular recovery and mitigate primary graft dysfunction, thereby reducing the duration of mechanical support and intensive care unit stay posttransplantation.

Peri-operative fever and LVAD: SIRS or impaired right ventricular strain?

BACKGROUND

An inflammatory milieu after left ventricular assist device (LVAD) implantation is associated with multi-organ dysfunction and pre-operative heightened inflammatory state is associated with right ventricular failure after LVAD implantation.

METHODS

We performed a retrospective analysis of 30 LVAD patients in our institution within the last 2 years for the development of fever and compared them to 30 non-LVAD open-heart surgery patients.

RESULTS

Our results suggest that patients undergoing LVAD implantation are more likely to develop fever in the immediate post-operative period compared to other open-heart surgeries. This is independent of pharmacological treatment, age, or ethnical background. Females and obese patients were more likely to develop fever.

CONCLUSION

Patients with right ventricular dysfunction, as demonstrated by elevated central venous pressure (CVP), had the strongest correlation with fever development. These results pose the question if there is a systemic inflammatory response-like phenomenon driven by increased right ventricular dysfunction.

Perioperative management of the vulnerable and failing right ventricle

Under recognition combined with suboptimal management of right ventricular (RV) dysfunction and failure is associated with significant perioperative morbidity and mortality. The contemporary perioperative team must be prepared with an approach for early recognition and prompt treatment. In this review, a consensus-proposed scoring system is described to provide a pragmatic approach for expeditious decision-making for these complex patients with a vulnerable RV. Importantly, this proposed scoring system incorporates the context of the planned surgical intervention. Further, as the operating room (OR) represents a unique environment where patients are susceptible to numerous insults, a practical approach to anesthetic management and monitoring both in the OR and in the intensive care unit is detailed. Lastly, an escalating approach to the management of RV failure and options for mechanical circulatory support is provided.

Epidemiology of perioperative RV dysfunction: risk factors, incidence, and clinical implications

In this edition of the journal, the Perioperative Quality Initiative (POQI) present three manuscripts describing the physiology, assessment, and management of right ventricular dysfunction (RVD) as pertains to the perioperative setting. This narrative review seeks to provide context for these manuscripts, discussing the epidemiology of perioperative RVD focussing on definition, risk factors, and clinical implications. Throughout the perioperative period, there are many potential risk factors/insults predisposing to perioperative RVD including pre-existing RVD, fluid overload, myocardial ischaemia, pulmonary embolism, lung injury, mechanical ventilation, hypoxia and hypercarbia, lung resection, medullary reaming and cement implantation, cardiac surgery, cardiopulmonary bypass, heart and lung transplantation, and left ventricular assist device implantation. There has however been little systematic attempt to quantify the incidence of perioperative RVD. What limited data exists has assessed perioperative RVD using echocardiography, cardiovascular magnetic resonance, and pulmonary artery catheterisation but is beset by challenges resulting from the inconsistencies in RVD definitions. Alongside differences in patient and surgical risk profile, this leads to wide variation in the incidence estimate. Data concerning the clinical implications of perioperative RVD is even more scarce, though there is evidence to suggest RVD is associated with atrial arrhythmias and prolonged length of critical care stay following thoracic surgery, increased need for inotropic support in revision orthopaedic surgery, and increased critical care requirement and mortality following cardiac surgery. Acute manifestations of RVD result from low cardiac output or systemic venous congestion, which are non-specific to the diagnosis of RVD. As such, RVD is easily overlooked, and the relative contribution of RV dysfunction to postoperative morbidity is likely to be underestimated.We applaud the POQI group for highlighting this important condition. There is undoubtedly a need for further study of the RV in the perioperative period in addition to solutions for perioperative risk prediction and management strategies. There is much to understand, study, and trial in this area, but importantly for our patients, we are increasingly recognising the importance of these uncertainties.

How Would I Treat My Own Chronic Thromboembolic Pulmonary Hypertension in the Perioperative Period?

Chronic thromboembolic pulmonary hypertension (CTEPH) results from an incomplete resolution of acute pulmonary embolism, leading to occlusive organized thrombi, vascular remodeling, and associated microvasculopathy with pulmonary hypertension (PH). A definitive CTEPH diagnosis requires PH confirmation by right-heart catheterization and evidence of chronic thromboembolic pulmonary disease on imaging studies. Surgical removal of the organized fibrotic material by pulmonary endarterectomy (PEA) under deep hypothermic circulatory arrest represents the treatment of choice. One-third of patients with CTEPH are not deemed suitable for surgical treatment, and medical therapy or interventional balloon pulmonary angioplasty presents alternative treatment options. Pulmonary endarterectomy in patients with technically operable disease significantly improves symptoms, functional capacity, hemodynamics, and quality of life. Perioperative mortality is <2.5% in expert centers where a CTEPH multidisciplinary team optimizes patient selection and ensures the best preoperative optimization according to individualized risk assessment. Despite adequate pulmonary artery clearance, patients might be prone to perioperative complications, such as right ventricular maladaptation, airway bleeding, or pulmonary reperfusion injury. These complications can be treated conventionally, but extracorporeal membrane oxygenation has been included in their management recently. Patients with residual PH post-PEA should be considered for medical or percutaneous interventional therapy.

The Roles of Venopulmonary Arterial Extracorporeal Membrane Oxygenation

OBJECTIVES

Concise definitive review of the use of venopulmonary arterial extracorporeal membrane oxygenation (V-PA ECMO) support in patients with cardiopulmonary failure.

DATA SOURCES

Original investigations identified through a PubMed search with search terms "percutaneous right ventricular assist device," "oxy-RVAD," "V-PA ECMO," and "veno-pulmonary arterial ECMO" were reviewed and evaluated for relevance.

STUDY SELECTION

Studies that included more than three patients supported with V-PA ECMO were included.

DATA EXTRACTION

Clinically relevant data from included studies, including patient-important outcomes, were summarized and discussed.

DATA SYNTHESIS

We identified four groups of patients where V-PA ECMO has been studied: acute respiratory distress syndrome, right ventricular dysfunction after left ventricular assist device placement, bridge to lung transplantation, and pulmonary embolism. Most identified works are small, single center, and retrospective in nature, precluding definitive conclusions regarding the efficacy of V-PA ECMO. There have been no clinical trials evaluating the efficacy of V-PA ECMO for any indication.

CONCLUSIONS

V-PA ECMO is a promising form of extracorporeal support for patients with right ventricular dysfunction. Future work should focus on identifying the optimal timing and populations for the use of V-PA ECMO.

Inhaled Pulmonary Vasodilators for the Treatment of Right Ventricular Failure in Cardio-Thoracic Surgery: Is One Better than the Others?

Right ventricular failure (RFV) is a potential complication following cardio-thoracic surgery, with an incidence ranging from 0.1% to 30%. The increase in pulmonary vascular resistance (PVR) is one of the main triggers of perioperative RVF. Inhaled pulmonary vasodilators (IPVs) can reduce PVR and improve right ventricular function with minimal systemic effects. This narrative review aims to assess the efficacy of inhaled nitric oxide and inhaled prostacyclins for the treatment of perioperative RVF. The literature, although statistically limited, supports the clinical similarity between them. However, it failed to demonstrate a clear benefit from the pre-emptive use of inhaled nitric oxide in patients undergoing left ventricular assist device implantation or early administration during heart-lung transplants. Additional concerns are related to cost safety and IPV use in pathologies associated with pulmonary venous congestion. The largest ongoing randomized controlled trial on adults (INSPIRE-FLO) is addressing whether inhaled Epoprostenol and inhaled nitric oxide are similar in preventing RVF after heart transplants and left ventricular assist device placement, and whether they are similar in preventing primary graft dysfunction after lung transplants. The preliminary analysis supports their equivalence. Several key points may be achieved by the present narrative review. When RVF occurs in the setting of elevated PVR, IPV should be the preferred initial treatment and they should be preventively used in patients at high risk of postoperative RVF. If severe refractory postoperative RVF occurs, IPVs should be combined with complementary pharmacology (inotropes and inodilators). If unsuccessful, right ventricular mechanical support should be established.

A classification system for pulmonary artery catheters

Flow-directed, balloon-tipped pulmonary artery catheters allow measuring cardiac output and other haemodynamic variables including intracardiac pressures. We propose classifying pulmonary artery catheters by generations and specifying additional measurement modalities. Based on the method used to measure cardiac output, pulmonary artery catheters can be classified into three generations: first-generation using intermittent pulmonary artery thermodilution; second-generation using a thermal filament for automated pulmonary artery thermodilution; and third-generation combining thermal filament-based automated pulmonary artery thermodilution and pulmonary artery pulse wave analysis. Each of these pulmonary artery catheter generations can include additional measurements, such as continuous mixed venous oxygen saturation, right ventricular ejection fraction and end-diastolic volume, and right ventricular pressure. This classification should help define indications for pulmonary artery catheters in clinical practice and research.

Right Heart Failure in the Intensive Care Unit: Etiology, Pathogenesis, Diagnosis, and Treatment

Right heart (RH) failure carries a high rate of morbidity and mortality. Patients who present with RH failure often exhibit complex aberrant cardio-pulmonary physiology with varying presentations. The treatment of RH failure almost always requires care and management from an intensivist. Treatment options for RH failure patients continue to evolve rapidly with multiple options available, including different pharmacotherapies and mechanical circulatory support devices that target various components of the RH circulatory system. An understanding of the normal RH circulatory physiology, treatment, and support options for the RH failure patients is necessary for all intensivists to improve outcomes. The purpose of this review is to provide clinical guidance on the diagnosis and management of RH failure within the intensive care unit setting, and to highlight the different pathophysiological manifestations of RH failure, its hemodynamics, and treatment options available at the disposal of the intensivist.

Perioperative Right Ventricular Dysfunction and Abnormalities of the Tricuspid Valve Apparatus in Patients Undergoing Cardiac Surgery

Right ventricular (RV) dysfunction frequently occurs after cardiac surgery and is linked to adverse postoperative outcomes, including mortality, reintubation, stroke, and prolonged ICU stays. While various criteria using echocardiography and hemodynamic parameters have been proposed, a consensus remains elusive. Distinctive RV anatomical features include its thin wall, which presents a triangular shape in a lateral view and a crescent shape in a cross-sectional view. Principal causes of RV dysfunction after cardiac surgery encompass ischemic reperfusion injury, prolonged ischemic time, choice of cardioplegia and its administration, cardiopulmonary bypass weaning characteristics, and preoperative risk factors. Post-left ventricular assist device (LVAD) implantation RV dysfunction is common but often transient, with a favorable prognosis upon resolution. There is an ongoing debate regarding the benefits of concomitant surgical repair of the RV in the presence of regurgitation. According to the literature, the gold standard techniques for assessing RV function are cardiac magnetic resonance imaging and hemodynamic assessment using thermodilution. Echocardiography is widely favored for perioperative RV function evaluation due to its accessibility, reproducibility, non-invasiveness, and cost-effectiveness. Although other techniques exist for RV function assessment, they are less common in clinical practice. Clinical management strategies focus on early detection and include intravenous drugs (inotropes and vasodilators), inhalation drugs (pulmonary vasodilators), ventilator strategies, volume management, and mechanical support. Bridging research gaps in this field is crucial to improving clinical outcomes associated with RV dysfunction in the near future.

[Anatomy-physiology considerations for cardiogenic shock with right ventricular involvement]

Since the discovery of right ventricular infarction, interest in the characteristics of the right ventricle has been increasing. Right ventricular function is now known to be a predictor of mortality in different settings. The right ventricle is a low-pressure, high-compliance, high-volume chamber. To carry out its normal function, it is coupled to the pulmonary circulation and the left ventricle. In the face of acute changes in pressure, volume overload and ischemia, it dilates to adapt to its new load. Its manifestation may be ventricular dysfunction and/or failure that will progress to cardiogenic shock due to right ventricular involvement. Various entities may be the cause of acute dysfunction: right ventricular infarction (alterations in contractility due to ischemia) and high-risk pulmonary thromboembolism (increased afterload). Both share a similar ventricular pathophysiology and high mortality without treatment. Understanding anatomy and physiology, dysfunction and acute ventricular failure are important to define a convenient diagnosis and treatment oriented towards pathophysiology. In this first part, the anatomy and physiology, acute right ventricular dysfunction/failure and cardiogenic shock are taken into consideration, from the perspective of these two entities. In another paper, treatment aimed at cardiogenic shock due to right ventricular involvement will be reviewed.

Considerations on the Management of Acute Postoperative Ischemia After Cardiac Surgery: A Scientific Statement From the American Heart Association

Acute postoperative myocardial ischemia (PMI) after cardiac surgery is an infrequent event that can evolve rapidly and become a potentially life-threatening complication. Multiple factors are associated with acute PMI after cardiac surgery and may vary by the type of surgical procedure performed. Although the criteria defining nonprocedural myocardial ischemia are well established, there are no universally accepted criteria for the diagnosis of acute PMI. In addition, current evidence on the management of acute PMI after cardiac surgery is sparse and generally of low methodological quality. Once acute PMI is suspected, prompt diagnosis and treatment are imperative, and options range from conservative strategies to percutaneous coronary intervention and redo coronary artery bypass grafting. In this document, a multidisciplinary group including experts in cardiac surgery, cardiology, anesthesiology, and postoperative care summarizes the existing evidence on diagnosis and treatment of acute PMI and provides clinical guidance.

Management of Acute Right Ventricular Failure

PURPOSE OF REVIEW

Acute right ventricular failure (RVF) is a frequent condition associated with high morbidity and mortality. This review aims to provide a current overview of the pathophysiology, presentation, and comprehensive management of acute RVF.

RECENT FINDINGS

Acute RVF is a common disease with a pathophysiology that is not completely understood. There is renewed interest in the right ventricle (RV). Some advances have been principally made in chronic right ventricular failure (e.g., pulmonary hypertension). Due to a lack of precise definition and diagnostic tools, acute RVF is poorly studied. Few advances have been made in this field. Acute RVF is a complex, frequent, and life-threatening condition with several etiologies. Transthoracic echocardiography (TTE) is the key diagnostic tool in search of the etiology. Management includes transfer to an expert center and admission to the intensive care unit (ICU) in most severe cases, etiological treatment, and general measures for RVF.

Monitoring of Levosimendan Administration in Patients with Pulmonary Hypertension Undergoing Cardiac Surgery and Effect of Two Different Dosing Schemes on Hemodynamic and Echocardiographic Parameters

INTRODUCTION

The perioperative management of patients with pulmonary hypertension (PH) undergoing cardiac surgery represents one of the most challenging clinical scenarios. This fact mainly depends on the relationship existing between PH and right ventricular failure (RVF). Levosimendan (LS) is an inodilator that might be an effective agent in the treatment of PH and RVF. The aim of this study was to examine the impact of the duration of cardiopulmonary bypass (CPB) on the therapeutic drug monitoring of LS and to evaluate the effect of preemptive administration of LS on perioperative hemodynamic and echocardiographic parameters in cardiac surgical patients with preexisting PH.

MATERIALS AND METHODS

In this study, LS was administered in adult patients undergoing cardiac surgery before CPB in order to prevent exacerbation of preexisting PH and subsequent right ventricular dysfunction. Thirty cardiac surgical patients with preoperatively confirmed PH were randomized to receive either 6 μg/kg or 12 μg/kg of LS after the induction of anesthesia. The plasma concentration of LS was measured after CPB. In this study, a low sample volume was used combined with a simple sample preparation protocol. The plasma sample was extracted by protein precipitation and evaporated; then, the analyte was reconstituted and detected using specific and sensitive bioanalytical liquid chromatography with mass spectrometry (LC-MS/MS) methodology. The clinical, hemodynamic, and echocardiographic parameters were registered and evaluated before and after the administration of the drug.

RESULTS

A fast bioanalytical LC-MS/MS methodology (a run time of 5.5 min) was developed for the simultaneous determination of LS and OR-1896, its main metabolite in human plasma. The LC-MS/MS method was linear over a range of 0.1-50 ng/mL for LS and 1-50 ng/mL for its metabolite OR-1896. Measured plasma concentrations of LS were inversely related to the duration of CPB. LS administration before CPB during cardiac surgery was effective in reducing pulmonary artery pressure and improving hemodynamic parameters after CPB, with a more pronounced and durable effect of the drug at the dose of 12 μg/kg. Additionally, administration of LS at a dose of 12 μg/kg in cardiac surgical patients with PH before CPB improved right ventricular function.

CONCLUSION

LS administration decreases pulmonary artery pressure and may improve right ventricular function in patients with PH undergoing cardiac surgery.