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.

A modified perfusion protocol for pulmonary endarterectomy in a patient with a hematologic malignancy treated with a tyrosine kinase inhibitor

Tyrosine kinase inhibitors (TKI) are known to be highly effective in the treatment of various cancers with kinase-domain mutations such as chronic myelogenous leukemia. However, they have important side effects such as increased vascular permeability and pulmonary hypertension. In patients undergoing pulmonary endarterectomy with deep hypothermic circulatory arrest, these side effects may exacerbate postoperative complications such as reperfusion edema and persistent pulmonary hypertension. We report on a simple modification of the perfusion strategy to increase intravascular oncotic pressure by retrograde autologous priming and the addition of packed cells and albumin in a patient treated with a TKI.

Chronic thromboembolic pulmonary hypertension: a review

Chronic thromboembolic pulmonary hypertension (CTEPH) is a unique form of pulmonary hypertension resulting from obstruction of the pulmonary artery by fibrotic thromboembolic material, usually initiated by recurrent or incomplete resolution of pulmonary embolism. This distinct form of pulmonary hypertension is classified under Group 4 of the World Health Organization classification. Further investigations are usually initiated, with transthoracic echocardiography followed by right heart catheterisation and pulmonary angiography as the gold standard. Definitive treatment is usually in the form of surgical pulmonary endarterectomy. Inoperable CTEPH is medically treated with pharmacological agents such as phosphodiesterase Type 5 inhibitors, endothelin receptor antagonists, soluble guanylate cyclase stimulators and prostacyclin. Recent developments have made balloon pulmonary angioplasty a viable option as well.

Time trends of pulmonary endarterectomy in patients with chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is considered as a rare but severe complication after acute pulmonary embolism and is potentially curable by pulmonary endarterectomy. We aimed to evaluate, over an 11-year period, time trends of in-hospital outcomes of pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension patients and to investigate predictors of the in-hospital course. We analyzed data on the characteristics, comorbidities, treatments, and in-hospital outcomes for all chronic thromboembolic pulmonary hypertension patients treated with pulmonary endarterectomy in the German nationwide inpatient sample between 2006 and 2016. Overall, 1398 inpatients were included. Annual number of pulmonary endarterectomy increased from 67 in 2006 to 194 in 2016 (P < 0.001), in parallel with a significant decrease of in-hospital mortality (10.9% in 2008 to 1.5% in 2016; P < 0.001). Patients' characteristics shifted slightly toward older age and higher prevalence of chronic renal insufficiency and obesity over time, whereas duration of hospital stay decreased over time. Independent predictors of in-hospital mortality were age (OR 1.03 (95%CI: 1.01-1.05); P = 0.001), right heart failure (2.55 (1.37-4.76); P = 0.003), in-hospital complications such as ischemic stroke (6.87 (1.06-44.70); P = 0.044) and bleeding events like hemopneumothorax (24.93 (6.18-100.57); P < 0.001). Annual pulmonary endarterectomy volumes per center below 10 annual procedures were associated with higher rates of adverse in-hospital outcomes. Annual numbers of chronic thromboembolic pulmonary hypertension patients treated with pulmonary endarterectomy increased markedly in Germany between 2006 and 2016, in parallel with a decrease of in-hospital mortality. Our findings suggest that perioperative management of pulmonary endarterectomy, institutional experience, and patient selection is crucial and has improved over time.

Chronic Thromboembolic Pulmonary Hypertension: JACC Focus Seminar

Chronic thromboembolic pulmonary hypertension (CTEPH) is the result of pulmonary arterial obstruction by organized thrombotic material stemming from incompletely resolved acute pulmonary embolism. The exact incidence of CTEPH is unknown but appears to approximate 2.3% among survivors of acute pulmonary embolism. Although ventilation/perfusion scintigraphy has been supplanted by computed tomographic pulmonary angiography in the diagnostic approach to acute pulmonary embolism, it has a major role in the evaluation of patients with suspected CTEPH, the presence of mismatched segmental defects being consistent with the diagnosis. Diagnostic confirmation of CTEPH is provided by digital subtraction pulmonary angiography, preferably performed at a center familiar with the procedure and its interpretation. Operability assessment is then undertaken to determine if the patient is a candidate for potentially curative pulmonary endarterectomy surgery. When pulmonary endarterectomy is not an option, pulmonary arterial hypertension-targeted pharmacotherapy and balloon pulmonary angioplasty represent potential therapeutic alternatives.

Transesophageal echocardiography for perioperative management in thoracic surgery

PURPOSE OF REVIEW

Perioperative transesophageal echocardiography (TEE) is most often employed during cardiac surgery. This review will summarize some of the recent findings relevant to TEE utilization during thoracic surgical procedures.

RECENT FINDINGS

Hemodynamic monitoring is a key component of goal-directed fluid therapy, which is also becoming more common for management of thoracic surgical procedures. Although usually not required for the anesthetic management of common thoracic surgeries, TEE is frequently used during lung transplantation and pulmonary thromboendarterectomy. Few clinical studies support current practice patterns, and most recommendations are based on expert opinion.

SUMMARY

Currently, routine use of TEE in thoracic surgery is often limited to specific high-risk patients and/or procedures. As in other perioperative settings, TEE may be utilized to elucidate the reasons for acute hemodynamic instability without apparent cause. Contraindications to TEE apply and have to be taken into consideration before performing a TEE on a thoracic surgical patient.

Anticoagulation management during pulmonary endarterectomy with cardiopulmonary bypass and deep hypothermic circulatory arrest

INTRODUCTION

Pulmonary endarterectomy requires cardiopulmonary bypass and deep hypothermic circulatory arrest, which may prolong the activated clotting time. We investigated whether activated clotting time-guided anticoagulation under these circumstances suppresses hemostatic activation.

METHODS

Individual heparin sensitivity was determined by the heparin dose-response test, and anticoagulation was monitored by the activated clotting time and heparin concentration. Perioperative hemostasis was evaluated by thromboelastometry, platelet aggregation, and several plasma coagulation markers.

RESULTS

Eighteen patients were included in this study. During cooling, tube-based activated clotting time increased from 719 (95% confidence interval = 566-872 seconds) to 1,273 (95% confidence interval = 1,136-1,410 seconds; p < 0.01) and the cartridge-based activated clotting time increased from 693 (95% confidence interval = 590-796 seconds) to 883 (95% confidence interval = 806-960 seconds; p < 0.01), while thrombin-antithrombin showed an eightfold increase. The heparin concentration showed a slightly declining trend during cardiopulmonary bypass. After protamine administration (protamine-to-heparin bolus ratio of 0.82 (0.71-0.90)), more than half of the patients showed an intrinsically activated coagulation test and intrinsically activated coagulation test without heparin effect clotting time >240 seconds. Platelet aggregation through activation of the P2Y12 (adenosine diphosphate test) and thrombin receptor (thrombin receptor activating peptide-6 test) decreased (both -33%) and PF4 levels almost doubled (from 48 (95% confidence interval = 42-53 ng/mL) to 77 (95% confidence interval = 71-82 ng/mL); p < 0.01) between weaning from cardiopulmonary bypass and 3 minutes after protamine administration.

CONCLUSION

This study shows a wide variation in individual heparin sensitivity in patients undergoing pulmonary endarterectomy with deep hypothermic circulatory arrest. Although activated clotting time-guided anticoagulation management may underestimate the level of anticoagulation and consequently result in a less profound inhibition of hemostatic activation, this study lacked power to detect adverse outcomes.

[Use of extracorporeal membrane oxygenation for pulmonary haemorrhage after pulmonary endarterectomy]

Pulmonary haemorrhage is one of the most severe complications of pulmonary endarterectomy. To the most effective methods of combating this potentially fatal complication belongs extracorporeal membrane oxygenation (ECMO). In this article we describe a clinical case report regarding intraoperative use of central veno-arterial ECMO for pulmonary haemorrhage following thromboendarterectomy from the pulmonary arteries. According to the data of some authors, long-term ECMO support (for more than 4 days) may lead to such severe consequences as rethrombosis of pulmonary arteries and impairment of cerebral circulation. In our case we managed to avoid such complications, taking into consideration that the duration of ECMO amounted to 21 days. Resulting from the carried out comprehensive therapeutic measures by the time of discharge from hospital, a significant decrease in pulmonary artery pressure was achieved, with events of residual pulmonary hypertension.

Assessing Right Ventricular Function in the Perioperative Setting, Part II: What About Catheters?

An-depth assessment of right ventricular function is important in a many perioperative settings. After exploring 2-dimensional echo-based evaluation, other proposed monitoring modalities are discussed. Pressure-based methods of right ventricular appraisal is discussed. Flow-based assessment is reviewed. An overview of the state of current right ventricular 3-dimensional echocardiography and its potential to construct clinical pressure-volume loops in conjunction with pressure measurements is provided. An overview of right ventricular assessment modalities that do not rely on 2-dimensional echocardiography is discussed. Tailored selection of monitoring modalities can be of great benefit for the perioperative physician. Integrating modalities offers optimal estimations of right ventricular function.

Perioperative anesthesia management for pulmonary endarterectomy: Adopting an established European Protocol for the Asian Population

Background

Anesthesia for pulmonary endarterectomy (PEA) has always been one of the challenges of anesthesia. As one of the leading cardiothoracic institutions in Southeast Asia, our hospital has vast interest in this subject. A local multidisciplinary team was deployed to an expert center in the United Kingdom (UK), and the experience was then integrated to the care of our patients. We present a case series of ten patients undergoing anesthesia for PEA, a first for our institution, and discuss techniques as well as potential complications.

Methods

Patients with chronic thromboembolic pulmonary hypertension were reviewed by a multidisciplinary team, and those who were suitable for surgical intervention subsequently underwent PEA. A total of ten patients were identified and operated on. The perioperative management and conduction of anesthesia for all patients followed a protocol adapted from the expert center in the UK, with revisions to cater to our Asian population.

Results

In the ten patients operated on, eight of them were successfully extubated on the first postoperative day. Apart from one incident of prolonged ventilator usage due to reperfusion lung injury and pneumonia, there were no major respiratory or hemodynamic complications. Certainly, six of the ten patients developed subdural hemorrhage after the commencement of enoxaparin, although none of them sustained any permanent neurological deficits.

Conclusion

We have demonstrated that with careful planning and a well-outlined protocol, anesthesia for PEA in an Asian population can be achieved with favorable outcomes. Further fine-tuning of the protocol is still required based on local expertise.

Atrial arrhythmias after pulmonary thromboendarterectomy

BACKGROUND AND OBJECTIVES

Atrial arrhythmias (AAs) are common after cardiac surgeries including pulmonary thromboendarterectomy (PTE). This study was done to identify patients at highest risk of developing post-PTE AA and their length of stay (LOS).

METHODS

We reviewed 521 consecutive patients referred to University of California San Diego (UCSD) for PTE and examined their demographics as well as their baseline pulmonary hemodynamics to determine risk factors for AA.

RESULTS

Overall, 24.2% of patients developed an AA after PTE. Patients who developed AA had a significantly longer Intensive Care Unit (ICU) LOS (median: 5 vs 3 days, P < 0.001) and postoperative LOS (median: 14 vs 9 days; P < 0.001). Patients who developed AA were more frequently male (63.2% male, P = 0.003), older (mean age 60.8 vs 50.7 years, P < 0.001), had a prior history of atrial fibrillation (80.2% of those who developed AA) and were more likely to have undergone concomitant Coronary Artery Bypass Graft (12.7% vs 6.6%, P = 0.028). Compared to those who did not develop AA, the cardiopulmonary bypass time was longer among those who developed AA (261.6 vs 253.8 minutes, P = 0.027). In a multivariate logistic regression model, the preoperative variables that predicted AA were age (odds ratio [OR], 1.058 per year, 95% confidence interval [CI]: 1.038-1.078), male sex (OR, 1.68, 95% CI: 1.06-2.64), prior AA (OR, 2.52, 95% CI: 1.23-5.15) and baseline right atrial pressure (OR, 1.039 per mm Hg, 95% CI: 1.000-1.079). While mortality rates were similar, patients who developed AA had more bleeding complications and more postoperative delirium.

CONCLUSIONS

AA is common after PTE surgery. The strongest risk factors for AA after PTE included the previous history of AA, age and male sex. Development of AA was associated with longer lengths of stay and more postoperative complications.

Critical Care of Patients After Pulmonary Thromboendarterectomy

Pulmonary thromboendarterectomy (PTE) remains the only curative surgery for patients with chronic thromboembolic pulmonary hypertension (CTEPH). Postoperative intensive care unit care challenges providers with unique disease physiology, operative sequelae, and the potential for detrimental complications. Central concerns in patients with CTEPH immediately after PTE relate to neurologic, pulmonary, hemodynamic, and hematologic aspects. Institutional experience in critical care for the CTEPH population, a multidisciplinary team approach, patient risk assessment, and integration of current concepts in critical care determine outcomes after PTE surgery. In this review, the authors will focus on specific aspects unique to this population, with integration of current available evidence and future directions. The goal of this review is to provide the cardiac anesthesiologist and intensivist with a comprehensive understanding of postoperative physiology, potential complications, and contemporary intensive care unit management immediately after pulmonary endarterectomy.

Methods of Pharmacological Treatment of Chronic Thromboembolic Pulmonary Hypertension Current Approaches to the Patients Management

In this paper we have discussed epidemiology, pathogenesis, and approaches to treatment of chronic thromboembolic pulmonary hypertension (CTEPH). CTEPH is a unique potentially curable form of pulmonary hypertension. The gold standard of CTEPH treatment is pulmonary thromboendarterectomy. However, about 40% of patients with CTEPH are inoperable due to distal surgically inaccessible lesions of the pulmonary vasculature, severe hemodynamic impairments, or other contraindications. In addition, nearly half of patients have persistent or recurrent pulmonary hypertension following surgery. Current guidelines support the use of pharmacotherapy in these patients. In the article we have presented results of main clinical studies of targeted drugs therapy (endothelin receptor antagonists, prostanoids, phosphodiesterase type 5 inhibitors, soluble guanylate cyclase stimulators) of patients with CTEPH. The only drug that has demonstrated robust clinical efficacy in terms of improvment hemodynamic parameters, exercise capacity and patients' quality of life is the stimulator of the soluble guanylate cyclase riociguat. The efficacy and safety of riociguat have been investigated in short-term and long-term studies with follow-up up to 6 years. Results of these studies have constituted the basis forits approval by the regulatory authorities of more than 50 countries for the treatment of inoperable CTEPH and persistent or recurrent CTEPH after pulmonary thromboendarterectomy. In the European Union, USA and many other countries, riociguat is the only pharmacological agent approved for these indications.

Pulmonary Artery Catheter Placement Aided by Transesophageal Echocardiography versus Pressure Waveform Transduction

OBJECTIVE

To compare pulmonary artery catheter (PAC) placement by transesophageal echocardiography combined with pressure waveform transduction versus the traditional technique of pressure waveform transduction alone.

DESIGN

A prospective, randomized trial.

SETTING

Single university hospital.

PARTICIPANTS

Forty-eight patients with chronic thromboembolic pulmonary hypertension (CTEPH) scheduled for pulmonary thromboendarterectomy.

INTERVENTIONS

PACs were placed in 48 patients with CTEPH scheduled for pulmonary thromboendarterectomy by either a combined approach (eg, transesophageal echocardiography [TEE] and pressure waveform transduction) or by pressure waveform transduction alone.

MEASUREMENTS AND MAIN RESULTS

Successful placement of the PAC via a combined technique or pressure waveform transduction alone was timed, number of attempts recorded, and final location noted. The final location of the pressure waveform-guided catheters was the proximal right pulmonary artery in 6 of 24 cases (25%), whereas the combined method resulted in successful placement in the proximal right pulmonary artery in 24 of 24 cases (100%). The pressure waveform technique resulted in a mean time to placement and mean number of attempts of 74 seconds and 1.70 attempts, respectively. The combined approach resulted in a mean time to placement and mean number of attempts of 89 seconds and 1.79 attempts, respectively. The combined method resulted in placement in the proximal right pulmonary artery significantly more often than the pressure-only method but did not reduce significantly the number of attempts or time required to place the catheter successfully. Additionally, among those cases that required more than 1 attempt or manipulation, there was no difference in the time to successful placement or the number of attempts required for successful placement.

CONCLUSION

TEE guidance during PAC insertion was hypothesized to result in a higher success rate, precise placement, and shorter times to placement. One hundred percent of the PACs inserted with TEE guidance were positioned successfully in the proximal right pulmonary artery, which is the institutional preference. Although the combined technique resulted in greater precision, the clinical significance of this is unknown. The time to placement benefit was not confirmed by this study.

The changing landscape of chronic thromboembolic pulmonary hypertension management

For patients with chronic thromboembolic pulmonary hypertension (CTEPH), the current standard of care involves surgical removal of fibro-thrombotic obstructions by pulmonary endarterectomy. While this approach has excellent outcomes, significant proportions of patients are not eligible for surgery or suffer from persistent/recurrent pulmonary hypertension after the procedure. The availability of balloon pulmonary angioplasty and the approval of the first medical therapy for use in CTEPH have significantly improved the outlook for patients ineligible for pulmonary endarterectomy. In this comprehensive review, we discuss the latest developments in the rapidly evolving field of CTEPH. These include improvements in imaging modalities and advances in surgical and interventional techniques, which have broadened the range of patients who may benefit from such procedures. The efficacy and safety of targeted medical therapies in CTEPH patients are also discussed, particularly the encouraging data from the recent MERIT-1 trial, which demonstrated the beneficial impact of using macitentan to treat patients with inoperable CTEPH, including those on background therapy. As the treatment options for CTEPH improve, hybrid management involving more than one intervention in the same patient may become a viable option in the near future.

Management of CTEPH is evolving rapidly, leading to improved patient outcomeshttp://ow.ly/rHrt30gUQWX

International survey on the perioperative management of pulmonary endarterectomy: the perfusion perspective

Introduction:

Pulmonary endarterectomy (PEA) is the most effective treatment available for chronic thromboembolic pulmonary hypertension (CTEPH). Patient selection, surgical technique and perioperative management have improved patient outcomes, which are traditionally linked to surgical and center experience. However, optimal perfusion care has not been well defined. The goal of the international survey was to better characterize the contemporary perfusion management of PEA and highlight similarities and controversies.

Method:

The combined caseload of 15 participating centers was 5,066 cases. Topics queried included materials and types of cardiopulmonary bypass (CPB) equipment, choice of prime, fluid management, deep hypothermia strategy, temperature management, treatment of acid-base abnormalities and intraoperative hematocrit as well as anticoagulation management for heparin-induced thrombocytopenia.

Conclusion:

Our assessment could provide a base for further advancement and may help design future studies to elucidate the impact of perfusion in this challenging field.

Pulmonary Artery Catheter Placement Using Transesophageal Echocardiography

OBJECTIVE

To assess the feasibility of pulmonary artery catheter placement using transesophageal echocardiography inclusive of a description of the technique.

DESIGN

A prospective, proof-of-concept study.

SETTING

Single university hospital.

PARTICIPANTS

Twenty patients with chronic thromboembolic pulmonary hypertension scheduled for pulmonary thromboendarterectomy.

INTERVENTIONS

Pulmonary artery catheters were placed in 20 patients solely by transesophageal echocardiographic guidance.

MEASUREMENTS AND MAIN RESULTS

Placement of the pulmonary artery catheter in the pulmonary artery with transesophageal echocardiography guidance in fewer than 10 minutes was considered successful placement. The time to placement was measured from advancement of the pulmonary artery catheter in the superior vena cava (20 cm) to a final location at the junction of the right pulmonary artery and main pulmonary artery. All 20 pulmonary artery catheters were placed successfully using transesophageal echocardiography guidance and the median time to placement was 43 seconds. In 9 of the 20 patients (45%), the catheter was placed successfully on the first attempt without any adjustments. However, in 9 others (45%), the catheter required manipulation under transesophageal echocardiography vision. In 3 patients (15%), the pulmonary artery catheter was observed to be coiled in the right atrium and in 1 instance (5%) manipulation of the catheter in the right ventricle was required to enter the outflow tract.

CONCLUSIONS

Transesophageal echocardiography is a viable adjunctive method to conventional pressure waveform placement of pulmonary artery catheters in potentially difficult patients.

Veno-arterial ECMO for rescue of severe airway hemorrhage with rigid bronchoscopy after pulmonary artery thromboendarterectomy

Pulmonary endarterectomy (PEA) is the treatment of choice to relieve pulmonary artery obstruction in patients with chronic thromboembolic pulmonary hypertension (CTEPH). We present a patient with airway obstruction and acute respiratory failure due to large blood clots obstructing the trachea and main left bronchus. This condition was accompanied by right ventricle failure and cardiogenic shock. A venoarterial ECMO system was used for cardiopulmonary support before extracting the clots and clearing the airway by rigid bronchoscopy.

Pulmonary endarterectomy for the treatment of chronic thromboembolic pulmonary hypertension

Pulmonary endarterectomy is a curative treatment option for patients with chronic thromboembolic pulmonary hypertension (CTEPH). There is a growing body of evidence suggesting that not only patients with CTEPH but also patients with pulmonary arterial obstructions and mean pulmonary artery pressures < 25 mmHg should be offered surgery. In this review, the recent literature regarding pathophysiology, diagnostic methods, decision making by an expert CTEPH team, and surgical techniques will be summarized. Novel alternative treatment options for inoperable CTEPH patients will be discussed, i.e. targeted medical therapy and balloon pulmonary angioplasty. For the future the major task will be to define a clear selection process for the optimal treatment of the individual CTEPH patient.

Acute Pain and Analgesic Requirements After Pulmonary Endarterectomy With Deep Hypothermic Circulatory Arrest

OBJECTIVES

To assess postoperative pain intensity and the analgesic requirements in the postoperative period in patients undergoing sternotomy for pulmonary endarterectomy involving deep hypothermic circulatory arrest.

DESIGN

Retrospective cohort study.

SETTING

Single-center hospital study.

PARTICIPANTS

Patients 18 years and older undergoing sternotomy for cardiac surgery between August 2012 and August 2014.

INTERVENTIONS

No modification to usual clinical practice.

MEASUREMENTS AND MAIN RESULTS

Intraoperative opioid and steroid administration, referral to the chronic pain unit, intensive care unit pain scores, and analgesic administration in the first 48 hours after the admission to the intensive care unit were recorded. Postoperative pain was evaluated by means of a categoric verbal scale from no pain (0) to severe pain (3); this is the routine analgesic scale used in the authors' intensive care unit. A total of 200 consecutive patients undergoing pulmonary endarterectomy (PEA group) were included in the study. No patient in the PEA group received morphine during surgery. The mean (standard deviation) postoperative pain intensity score at 24 hours was 0.30 (0.54) in the PEA group. Postoperative morphine was administered in 39% of patients. No PEA patient was referred to the chronic pain unit after hospital discharge.

CONCLUSION

The total analgesic requirements and pain score of patients undergoing sternotomy for pulmonary endarterectomy with deep hypothermic circulatory arrest seemed to be low.

Pulmonary endarterectomy: the potentially curative treatment for patients with chronic thromboembolic pulmonary hypertension

Pulmonary endarterectomy (PEA) is the treatment of choice to relieve pulmonary artery obstruction in patients with chronic thromboembolic pulmonary hypertension (CTEPH). It is a complex surgical procedure with a simple principle: removal of obstructive thromboembolic material from the pulmonary arteries in order to reduce pulmonary vascular resistance, relieve pulmonary hypertension (PH) and alleviate right ventricular dysfunction. In the majority of patients there is symptomatic and prognostic benefit. However, not all patients with CTEPH are suitable for treatment with PEA. Operability assessment is not always easy, being largely subjective and based on experience. It is therefore important that all patients are referred to an experienced CTEPH centre for careful evaluation of suitability for surgery. The most common reason for inoperability is distal vasculopathy accounting for a high proportion of the vascular resistance. Surgery requires cardiopulmonary bypass and periods of deep hypothermic circulatory arrest. Complications include reperfusion lung injury and persistent PH. However, with careful patient selection, surgical technique and post-operative management, PEA is a highly effective treatment with mortality rates <5% at experienced centres. Patients who are unsuitable for surgery may be candidates for medical therapy.

A review of pulmonary endarterectomy as a CTEPH treatment, including patient assessment, risks and outcomeshttp://ow.ly/L82F7