Outcomes of pulmonary endarterectomy for treatment of extreme thromboembolic pulmonary hypertension

Unilateral Chronic Thromboembolic Pulmonary Disease: Do Patients Benefit From Thromboendarterectomy? Case Series From Three CTEPH Centres

BACKGROUND

Unilateral chronic thromboembolism pulmonary disease (CTEPD) is very rare. There is limited information on the safety and efficacy of pulmonary endarterectomy (PEA) in this population. This study investigated the effectiveness of PEA in this unique disease.

METHODS

This multicentre study included patients with unilateral CTEPD from three referral centres in the United States, Turkey, and Iran. The patients' demographic information, 6-minute walk test distance (6MWD), New York Heart Association (NYHA) functional class, and haemodynamics were evaluated.

RESULT

Of the 1,031 patients who had undergone PEA, 39 patients (3.7%) had pure unilateral involvement, of whom 28 were female (71.8%). There was a significant improvement in the mean pulmonary artery pressure (mPAP, 26 mmHg vs 21 mmHg; p=0.011) and pulmonary vascular resistance (PVR, 202 vs 136 dynes∗sec1∗cm-5; p=0.014). There was also a significant improvement in NYHA functional class (p<0.001) and 6MWD (360 vs 409 m; p<0.001). In the nine patients with normal haemodynamic parameters at rest, there was no significant change in median 6MWD (448.5 vs 449 m; p=0.208), mPAP (19 mmHg vs 16.5 mmHg; p=0.397), and PVR (129 vs 84.5 dynes∗sec1∗cm-5; p=0.128). The most common postoperative complication was ipsilateral pleural effusion. One patient needed extracorporeal membrane oxygenation support. No patient died within the 1-year follow up.

CONCLUSION

Pulmonary endarterectomy is a safe and effective procedure for improving the symptoms and haemodynamic parameters of patients with unilateral CTEPH. Symptomatic patients with unilateral chronic thromboembolic disease are suitable for PEA.

Perioperative extracorporeal membrane oxygenation support for pulmonary endarterectomy: A 17-year experience from the UK national cohort

BACKGROUND

Pulmonary endarterectomy (PEA) is the guideline-recommended treatment for patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, some patients develop severe cardiopulmonary compromise before surgery, intraoperatively, or early postoperatively. This may result from advanced CTEPH, reperfusion pulmonary edema, massive endobronchial bleeding, or right ventricular (RV) failure secondary to residual pulmonary hypertension. Conventional cardiorespiratory support is ineffective when these complications are severe. Since 2005, we used extracorporeal membrane oxygenation (ECMO) as a rescue therapy for this group. We review our experience with ECMO support in these patients.

METHODS

This study was a retrospective analysis of patients who received perioperative ECMO for PEA from a single national center from August 2005 to July 2022. Data were prospectively collected.

RESULTS

One hundred and ten patients (4.7%) had extreme cardiorespiratory compromise requiring perioperative ECMO. Nine were established on ECMO before PEA. Of those who received ECMO postoperatively, 39 were for refractory reperfusion lung injury, 20 for RV failure, 31 for endobronchial bleeding, and the remaining 11 were for "other" reasons, such as cardiopulmonary resuscitation following late tamponade and aspiration pneumonitis. Sixty-two (56.4%) were successfully weaned from ECMO. Fifty-seven patients left the hospital alive, giving a salvage rate of 51.8%. Distal disease (Jamieson Type III) and significant residual pulmonary hypertension were also predictors of mortality on ECMO support. Overall, 5- and 10-year survival in patients who were discharged alive following ECMO support was 73.9% (SE: 6.1%) and 58.2% (SE: 9.5%), respectively.

CONCLUSIONS

Perioperative ECMO support has an appropriate role as rescue therapy for this group. Over 50% survived to hospital discharge. These patients had satisfactory longer-term survival.

Role of Surgical and Medical Management of Chronic Thromboembolic Pulmonary Hypertension: A Systematic Review

Chronic thromboembolic pulmonary hypertension (CTEPH) is underdiagnosed and has recently surfaced as one of the leading triggers of severe pulmonary hypertension. This disease process is described by structural changes of pulmonary arteries such as fibrous stenosis, complete obliteration, or the presence of a resistant intraluminal thrombus, resulting in increased pulmonary resistance and eventually progressing to right-sided heart failure. Hence, this study aims to describe the current treatments for CTEPH and their efficacy in hemodynamic improvement and prevention of recurring thromboembolic episodes in patients. This systematic review promptly follows the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. On February 13, 2022, our team searched through the following databases: PubMed, ProQuest, and ScienceDirect. The following keywords were used across all databases: CTEPH AND Pulmonary Endarterectomy (PEA), CTEPH AND Balloon Pulmonary Angioplasty (BPA), and CTEPH AND Medical Therapy OR Anticoagulation therapy. Twenty-nine thousand eighty-nine articles on current management techniques (PEA, Balloon angioplasty, anticoagulants) were selected, analyzed, and reviewed with each other. We found 19 articles concerning PEA, 15 concerning BPA, and six regarding anticoagulants. Most papers showed high success rates and promising evidence of PEA and anticoagulants as a post-operative regimen. BPA was the least preferred but is still reputable in patients unfit for invasive techniques. CTEPH is a condition presenting with either fibrous stenosis, complete obliteration of the artery, or a clogged thrombus. Recent studies have shown three techniques that physicians have used to treat CTEPH: balloon-pulmonary angioplasty, PEA, and medical management with anticoagulants. PEA followed by anticoagulants is preferred to balloon pulmonary angioplasties. CTEPH is an ongoing topic in research; as it continues to be researched, we hope to see more management techniques available.

Distribution of thrombus predicts severe reperfusion pulmonary edema after pulmonary endarterectomy

OBJECTIVES

Patients underwent pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH). This study aimed to investigate the effect of thrombus distribution on the occurrence of severe reperfusion pulmonary edema (RPE) and identify specific parameters for predicting severe RPE.

METHODS

Patients with CTEPH who underwent PEA surgery were retrospectively analyzed. The thrombus in pulmonary arteries were evaluated through computed tomography pulmonary angiography. Based on presence of prolonged artificial ventilation, extracorporeal membrane oxygenation required, or perioperative death due to RPE, the patients were divided into the severe RPE and without severe RPE groups.

MAIN RESULTS

Among the 77 patients (29 women), 16 (20.8%) patients developed severe RPE. The right major pulmonary artery (RPA) (0.64[0.58, 0.73] vs 0.58[0.49, 0.64]; p = 0.008) and pulmonary artery trunk (PAT) thrombus ratios (0.48[0.44, 0.61] vs 0.42[0.39, 0.50]; p = 0.009) (the PAT ratio is expressed as the sum of the right middle lobe clot burden and right lower lobe clot burden divided by the total clot burden multiplied by 100) of the severe RPE group was significantly higher than that of the without severe RPE group. Receiver operator characteristics curve identified a PAT ratio of 43.4% as the threshold with areas under the curve = 0.71(95%CI 0.582; 0.841) for the development of severe RPE (sensitivity 0.875, specificity 0.541). The logistic regression analysis demonstrated that age, period from symptom onset to PEA, NT-pro BNP, preoperative mPAP, preoperative PVR, RPA ratio, and PAT ratio were associated with the development of severe RPE. Multivariable logistic regression analysis revealed PAT ratio (odds ratio = 10.2; 95% confidence interval 1.87, 55.53, P = 0.007) and period from symptom onset to PEA (OR = 1.01; 95% CI = 1.00-1.02, P = 0.015) as independent risk factors for the development of severe RPE.

CONCLUSIONS

The thrombus distribution could be a key factor in the severity of RPE. PAT ratio and medical history could predict the development of severe RPE.

RC time (resistance × compliance) is related to residual symptom after pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension

Background

Right ventricular (RV) afterload is widely assessed by pulmonary vascular resistance (PVR). However, RV afterload is underestimated because PVR does not account for the pulsatile load. The pulsatile load is often evaluated by pulmonary arterial compliance (PAC). The RC (resistance-compliance) time, which is calculated from the product of PVR and PAC, is considered to remain constant under medical therapy. However, little is known on how RC time is affected by invasive therapy in chronic thromboembolic pulmonary hypertension (CTEPH). This study aimed to evaluate change of RC time in patients underwent pulmonary endarterectomy (PEA). Furthermore, we investigated the clinical relevance of RC time.

Methods

We reviewed consecutive 50 patients except for death case underwent PEA. Baseline clinical parameters including RC time before performing PEA and follow-up were evaluated. Patients was classified as decrease or non-decrease according to change of RC time. Furthermore, we classified patients into a NYHA I group who had no symptom after treatment and a residual symptom group in order to investigate the relationship of RC time to residual symptoms.

Results

RC time was significantly decreased after PEA (0.54 ± 0.16 to 0.45 ± 0.12 sec, p < 0.001). Residual symptom after PEA of Decrease group were significantly better than that of Non-decrease group in RC time (12 patients, 40% vs. 11 patients, 78.6%, p < 0.02). Furthermore, multivariate analysis revealed that only RC time after PEA was independently associated with residual symptom (OR 1.026, 95% CI 1.005–1.048; p = 0.017).

Conclusions

RC time was decreased after PEA, and might be a possible indicator for predicting PEA success.

Pulmonary endarterectomy in severe chronic thromboembolic pulmonary hypertension: the Toronto experience

BACKGROUND

Pulmonary endarterectomy (PEA) in severe chronic thromboembolic pulmonary hypertension (CTEPH) is associated with higher risks. However, recent evidence suggests that these risks may be mitigated with the use of extracorporeal membrane oxygenation (ECMO).

METHODS

We performed a retrospective analysis of 401 consecutive patients undergoing PEA at the Toronto General Hospital between August 2005 and March 2020. Patients with severe CTEPH defined by pulmonary vascular resistance (PVR) >1,000 dynes.s.cm-5 at the time of diagnosis were compared to those with PVR <1,000 dynes.s.cm-5.

RESULTS

The New York Heart Association (NYHA) functional class, brain natriuretic peptide (BNP) and 6-minute walk distance were worse in patients with PVR >1,000 dynes.s.cm-5. A greater proportion of patients with PVR >1,000 dynes.s.cm-5 was treated with targeted pulmonary hypertension (PH) medical therapy (38% vs. 18%, P<0.001) and initiated on inotropic support (7% vs. 0.3%, P<0.001) before PEA. Since 2014, the ECMO utilization rate increased in patients with PVR >1,000 dynes.s.cm-5 compared to those with PVR <1,000 dynes.s.cm-5 (18% vs. 3.1%, P<0.001). The hospital mortality in patients with PVR >1,000 dynes.s.cm-5 decreased from 10.3% in 2005-2013 to 1.6% in 2014-2020 (P=0.05), while the hospital mortality in patients with PVR <1,000 dynes.s.cm-5 remained stable (1.2% in 2005-2013 vs. 2.7% in 2014-2020, P=0.4). The overall survival reached 84% at 10 years in patients with PVR >1,000 dynes.s.cm-5 compared to 78% in patients with PVR <1,000 dynes.s.cm-5 (P=0.7).

CONCLUSIONS

The early and long-term results of PEA in patients with severe CTEPH are excellent despite greater postoperative risks. ECMO as a bridge to recovery after PEA can be useful in patients with severe CTEPH.

May-Thurner Anatomy in Patients With Chronic Thromboembolic Pulmonary Hypertension: An Important Clinical Association

OBJECTIVES

The aim of this study was to investigate the incidence of May-Thurner anatomy (MTA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) and identify its predictors.

BACKGROUND

MTA is an anatomical variant characterized by compression of left common iliac vein by the overlying right iliac artery. Over time, this leads to venous intimal scarring, blood flow stasis, and the development of deep vein thrombosis (DVT). DVT is a known risk factor for the development of CTEPH. The prevalence of this anatomical variation in patients with CTEPH is unknown.

METHODS

A retrospective chart review was conducted in patients referred to Temple University Hospital's cardiac catheterization laboratory for the evaluation of CTEPH between January 2016 and June 2020. Among these patients, those who underwent invasive venography were evaluated for the presence of angiographic MTA. Multivariate regression was used to identify factors associated with presence of MTA.

RESULTS

A total of 193 patients with CTEPH were referred for pulmonary angiography, of whom 148 patients underwent invasive venography. MTA was identified in 44 patients (29.7%). Factors associated with the presence of MTA were lower extremity DVT (odds ratio: 3.5; 95% confidence interval: 1.58-7.8; P = 0.002), and left lower extremity post-thrombotic syndrome (odds ratio: 2.0; 95% confidence interval: 0.98-4.1; P = 0.05). Patients with MTA were more likely to undergo pulmonary thromboendarterectomy than patients without MTA (79.5% vs 58.7%; P = 0.015).

CONCLUSIONS

MTA is very common in patients with CTEPH. History of lower extremity DVT and or left lower extremity post-thrombotic syndrome was associated with the presence of MTA.

Experience with pulmonary endarterectomy: Lessons learned across 17 years

BACKGROUND

Pulmonary endarterectomy is potential curative therapy for chronic thromboembolic pulmonary hypertension patients. Here, we present our experience with pulmonary endarterectomy spanning 17 years and detail our management strategy.

METHODS

This is a single-centre retrospective study conducted on chronic thromboembolic pulmonary hypertension patients who underwent pulmonary endarterectomy at our centre across 17 years.

RESULTS

Between 2004 and 2020, 591 patients underwent pulmonary endarterectomy. Amongst them 429 (72.4%) were males with a male to female ratio of 2.6:1, the median age was 38 (range, 14-73) years. The median length of hospital stay was 11 days (IQR, 8-16). Extra corporeal membranous oxygenation was used in 82 (13.9%) patients during/after surgery, out of whom 28 (34.1%) survived. There were 70 (11.8%) in-hospital deaths. Female gender (p < 0.01), pulmonary artery systolic pressure >100 mmHg (p < 0.05) and use of extra corporeal membrane oxygenation (p < 0.001) were significant risk factors for in-hospital mortality. The mortality in the first period (2004-2012) was 15.7% which reduced to 9.1% in the later period (2013-2020). The reduction in mortality rate was 42% (p < 0.05). Following pulmonary endarterectomy, there was a significant reduction in pulmonary artery systolic pressure (86.68 ± 24.38 vs. 39.71 ± 13.13 mmHg; p < 0.001) and improvement in median walk distance as measured by 6-min walk test on follow-up (300 vs. 450 meters; p < 0.001). The median duration of follow-up was 8 months (inter-quartile range: 2-24).

CONCLUSIONS

pulmonary endarterectomy has a learning curve, high pulmonary vascular resistance alone is not a contraindication for surgery. Patients following surgery have improved survival and quality of life.

Raising the bar to ultradisciplinary collaborations in management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is an underdiagnosed and potentially fatal subgroup of pulmonary hypertension, if left untreated. Clinical signs include exertional dyspnea and non-specific symptoms. Diagnosis requires multimodality imaging and heart catheterization. Pulmonary endarterectomy, an open heart surgery, is the gold standard treatment of choice in selected patients in specialized centers. Targeted medical therapy and balloon pulmonary angioplasty can be effective in high-risk patients with significant comorbidities, distal pulmonary vascular obstructions, or recurrent/persistent pulmonary hypertension after pulmonary endarterectomy. Currently, there is a limited number of data regarding novel coronavirus-2019 infection in patients with chronic thromboembolic pulmonary hypertension and the changing spectrum of the disease during the pandemic. Challenging times during this outbreak due to healthcare crisis and relatively higher case-fatality rates require convergence; that is an ultradisciplinary collaboration, which crosses disciplinary and sectorial boundaries to develop integrated knowledge and new paradigms. Management strategies for the "new normal" such as virtual care, preparedness for further threats, redesigned standards and working conditions, reevaluation of specific recommendations, and online collaborations for optimal decisions for chronic thromboembolic pulmonary hypertension patients may change the poor outcomes.

Correlation Between Perfusion Abnormalities Extent in Ventilation/Perfusion SPECT/CT with Hemodynamic Parameters in Patients with Chronic Thromboembolic Pulmonary Hypertension

Objectives

Chronic thromboembolic pulmonary hypertension (CTEPH) is a type of pulmonary hypertension with persistent pulmonary vascular obstruction and exercise intolerance, which may benefit from pulmonary endarterectomy (PEA). Ventilation/perfusion (V/Q) scan is the preferred screening test of CTEPH, which can be used to assess the anatomical extent of the disease. This study aimed to analyze the correlation between the extent of mismatched Q defects in V/Q single photon emission computed tomography/computed tomography (SPECT/CT) with preoperative clinical and hemodynamic parameters in patients with CTEPH.

Methods

A total of 102 patients with CTEPH prior to PEA having V/Q SPECT/CT scans were retrospectively reviewed. Age, gender, New York Heart Association classification, intraoperative right-sided heart catheterization (mPAP and PVR), and 6-minute walk test (6MWT) findings were obtained from clinical records of patients.

Results

Linear regression analysis showed a significant but weak correlation between the preoperative mPAP and PVR with the extent of mismatched Q defects in V/Q SPECT/CT (rs=0.09474 with p=0.0016 and rs=0.045 with p=0.045, respectively). No significant correlation was found between 6MWT and extent of mismatched Q defects in V/Q SPECT/CT (p>0.05).

Conclusion

A quantitative assessment of Q defects on V/Q SPECT/CT might provide information about hemodynamic parameters in patients with CTEPH.

The extent of enlarged bronchial arteries is not correlated with the development of reperfusion pulmonary edema after pulmonary endarterectomy in patients with chronic thromboembolic pulmonary hypertension

This study investigated whether dilated bronchial arteries are associated with reperfusion pulmonary edema in patients with chronic thromboembolic pulmonary hypertension. Results showed that the extent of enlarged bronchial arteries was not associated with the development of reperfusion pulmonary edema, whereas the residual pulmonary hypertension had a significant association.

Surgical and Percutaneous Interventions for Chronic Thromboembolic Pulmonary Hypertension

The treatment of chronic thromboembolic pulmonary hypertension has expanded considerably. The ability to endarterectomize chronic thromboembolic material, the availability of pulmonary hypertension medical therapy to treat inoperable chronic thromboembolic pulmonary hypertension and/or residual pulmonary hypertension, and the rebirth of pulmonary balloon angioplasty have changed the management landscape. Patient selection requires a multidisciplinary evaluation at an experienced center. What is inoperable chronic thromboembolic pulmonary hypertension to one group may be operable chronic thromboembolic pulmonary hypertension to another. The ultimate challenge then becomes which intervention provides the optimal long-term outcome for any individual patient.

Chronic Thromboembolic Pulmonary Hypertension: Evolving Therapeutic Approaches for Operable and Inoperable Disease

Chronic thromboembolic pulmonary hypertension (CTEPH), a rare consequence of an acute pulmonary embolism, is a disease that is underdiagnosed, and surgical pulmonary thromboendarterectomy (PTE) remains the preferred therapy. However, determination of operability is multifactorial and can be challenging. There is growing excitement for the percutaneous treatment of inoperable CTEPH with data from multiple centers around the world showing the clinical feasibility of balloon pulmonary angioplasty. Riociguat remains the only approved medical therapy for CTEPH patients deemed inoperable or with persistent pulmonary hypertension after PTE. We recommend that expert multidisciplinary CTEPH teams be developed at individual institutions. Additionally, optimal and standardized techniques for balloon pulmonary angioplasty need to be developed along with dedicated interventional equipment and appropriate training standards. In the meantime, the percutaneous revascularization option is appropriate for patients deemed inoperable in combination with targeted medical therapy, or those who have failed to benefit from surgery.

Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is associated with several risk factors but is most frequently seen as a rare consequence of an acute pulmonary embolism. Surgical pulmonary thromboendarterectomy (PTE) is potentially curative for CTEPH with the best outcomes seen for the treatment of primarily proximal, accessible lobar or segmental disease. For surgically inoperable patients, percutaneous balloon pulmonary angioplasty (BPA) is feasible and has good short- to mid-term efficacy outcomes. This review focuses on the technique and outcomes associated with BPA which has emerged as a new therapeutic option for CTEPH.

Measurement of extravascular lung water to diagnose severe reperfusion lung injury following pulmonary endarterectomy: a prospective cohort clinical validation study

The measurement of extravascular lung water is a relatively new technology which has not yet been well validated as a clinically useful tool. We studied its utility in patients undergoing pulmonary endarterectomy as they frequently suffer reperfusion lung injury and associated oedematous lungs. Such patients are therefore ideal for evaluating this new monitor. We performed a prospective observational cohort study during which extravascular lung water index measurements were taken before and immediately after surgery and postoperatively in intensive care. Data were analysed for 57 patients; 21 patients (37%) experienced severe reperfusion lung injury. The first extravascular lung water index measurement after cardiopulmonary bypass failed to predict severe reperfusion lung injury, area under the receiver operating characteristic curve 0.59 (95%CI 0.44–0.74). On intensive care, extravascular lung water index correlated most strongly at 36 h, area under the receiver operating characteristic curve 0.90 (95%CI 0.80–1.00). Peri‐operative extravascular lung water index is not a useful measure to predict severe reperfusion lung injury after pulmonary endarterectomy, however, it does allow monitoring and measurement during the postoperative period. This study implies that extravascular lung water index can be used to directly assess pulmonary fluid overload and that monitoring patients by measuring extravascular lung water index during their intensive care stay is useful and correlates with their clinical course. This may allow directed, pre‐empted therapy to attenuate the effects and improve patient outcomes and should prompt further studies.

Involvement of pulmonary arteriopathy in the development and severity of reperfusion pulmonary edema after pulmonary endarterectomy

Reperfusion pulmonary edema (RPE) is a common complication after pulmonary endarterectomy (PEA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, the precise mechanisms underlying the development of RPE remain unclear. To evaluate the effects of pulmonary vasculopathy on RPE, the severity of the pulmonary arteriopathies and venopathies of lung tissues biopsied during PEA were pathologically quantified in 33 CTEPH patients. The severity of RPE was classified from grade 0 (no RPE) to 4 (death due to RPE) based on the arterial oxygen tension/inspiratory oxygen fraction (P/F ratio) and necessity of respiratory management. Among the 33 patients (27 women; mean age = 63.3 years), 17 (51.5%) patients developed RPE. The severity of pulmonary arteriopathy (obstruction ratio) correlated with the grade of RPE (r = 0.576, P = 0.0005). The obstruction ratio also correlated with the P/F ratio (r = −0.543, P = 0.001) and the perioperative mean pulmonary arterial pressure (r = 0.445, P = 0.009). Multivariate logistic regression analysis revealed that the obstruction ratio was a significant independent determinant for the development of RPE (odds ratio = 15.7; 95% confidence interval = 2.29–108.00, P = 0.005). In conclusion, pulmonary arteriopathy could be a determinant of the development and severity of RPE after PEA.

Case series of seven women with uterine fibroids associated with venous thromboembolism and chronic thromboembolic disease

Uterine fibroids have been described as an associate to acute venous thromboembolism (VTE), with case reports showing an association between large uterine fibroids, acute deep venous thrombosis (DVT), and acute pulmonary embolism (PE). However, there is little known about the association or causation between uterine fibroids, chronic thromboembolic disease (CTED), and chronic thromboembolic pulmonary hypertension (CTEPH). We report on six women with uterine fibroids and CTEPH, as well as one woman with CTED, all of whom presented with exertional dyspnea, lower extremity swelling, and in the cases of CTEPH, clinical, echocardiographic, and hemodynamic evidence of pulmonary hypertension and right heart failure. Compression of the pelvic veins by fibroids was directly observed with invasive venography or contrast-enhanced computed tomography in five cases. All seven women underwent pulmonary thromboendarterectomy (PTE) followed by marked improvement in functional, clinical, and hemodynamic status.

Sequential Hybrid Therapy With Pulmonary Endarterectomy and Additional Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension

Background

Residual symptoms after pulmonary endarterectomy (PEA) remain as the clinical issues to be solved. Additional balloon pulmonary angioplasty (BPA) after PEA showed its efficacy with symptoms in a case series, although long‐term spontaneous recovery of exercise ability after PEA was also reported. However, no studies have validated the clinical efficacy of additional BPA by directly comparing PEA with and without BPA. The aim of this study was to retrospectively evaluate the efficacy of additional BPA as a sequential hybrid therapy for chronic thromboembolic pulmonary hypertension after PEA.

Methods and Results

Among 44 patients with chronic thromboembolic pulmonary hypertension, 20 patients had residual symptoms after PEA. Of those, 10 patients underwent additional BPA (hybrid group) and were compared with the other 10 patients, who were followed up without BPA (PEA group). The period from PEA to additional BPA was 7.3±2.3 months. In hybrid group, mean pulmonary arterial pressure was significantly improved by PEA (40.6±1.8 to 26.9±3.1 mm Hg, P=0.001) and improved further (to 16.7±1.8 mm Hg, P=0.002) with additional BPA, which resulted in remarkable improvement in World Health Organization (WHO) functional class (pre‐ to post‐BPA: class I/II/III/IV, 0/5/4/1 to 7/3/0/0; P<0.001). Compared with the PEA group at follow‐up, the hybrid group achieved better mean pulmonary arterial pressure (18.7±1.7 versus 30.2±3.2 mm Hg, P=0.008), WHO functional class (class I/II/III/IV, 7/3/0/0 versus 0/8/2/0; P=0.001), and 6‐minute walking distance (429±38 versus 319±22 m, P=0.028).

Conclusions

A sequential hybrid strategy improved residual symptoms and exercise capacity compared with single‐PEA therapy.

Haemodynamic effects of riociguat in inoperable/recurrent chronic thromboembolic pulmonary hypertension

OBJECTIVE

We compared the haemodynamic effects of riociguat in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) or persistent/recurrent CTEPH after pulmonary endarterectomy in the Chronic Thromboembolic Pulmonary Hypertension Soluble Guanylate Cyclase-Stimulator Trial 1 study.

METHODS

Patients with inoperable or persistent/recurrent CTEPH (n=261; mean± SD age 59±14 years; 66% women) were randomised to riociguat (up to 2.5 mg three times daily) or placebo. Haemodynamic parameters were assessed at baseline and week 16.

RESULTS

Riociguat decreased pulmonary vascular resistance (PVR) in inoperable (n=189; least-squares mean difference: -285 dyn s/cm5 (95% CI -357 to -213); p<0.0001) and persistent/recurrent (n=72; -131 dyn s/cm5 (95% CI -214 to -48); p=0.0025) patients. Cardiac index improved in inoperable patients by a least-squares mean difference of +0.6 L/min/m2 (95% CI 0.4 to 0.7; p<0.0001), while in persistent/recurrent patients the change was +0.2 L/min/m2 (95% CI -0.1 to 0.5; p=0.17). Mean pulmonary artery pressure decreased in inoperable and persistent/recurrent patients(-4.7 mm Hg (95% CI -6.9 to -2.6; p<0.0001 and -4.8 mm Hg (-8.2 to -1.5; p=0.0055), respectively). For all patients, changes in 6 min walk distance correlated with changes in PVR (r=-0.29 (95% CI -0.41 to -0.17); p<0.0001) and cardiac index (r=0.23 (95% CI 0.10 to 0.35); p=0.0004).

CONCLUSIONS

Riociguat improved haemodynamics in patients with inoperable CTEPH or persistent/recurrent CTEPH.

TRIAL REGISTRATION NUMBER

NCT00855465.

[5-year surgical results in patients with chronic postembolic pulmonary hypertension]

AIM

To evaluate 5-year results of surgical treatment of patients with chronic postembolic pulmonary hypertension.

MATERIAL AND METHODS

170 patients with chronic postembolic pulmonary hypertension underwent pulmonary thrombendarterectomy. Mean age was 48±21.5 years. The operation was carried out using standard technique with hypothermia and circulatory arrest. We have analyzed clinical and functional status of 47 patients (23 males) prior to surgery and in long-term postoperative period (5-6 years). Distance of 6-minute walk test, mean pulmonary artery pressure and vascular resistance according to right heart catheterization, RV ejection fraction and volumes according to echocardiography, pulmonary artery diameter according to CT-angiography were analyzed.

RESULTS

In remote postoperative period average distance of 6-minute walk test was increased by 2.8 times compared with initial values. Right heart catheterization revealed reduction of the average pulmonary pressure from 54.04±23.35 to 25.16±15.41 mmHg and vascular resistance from 539.66±120.59 dyn·sec·cm^-5 to 101.39±89.20 dyn·sec·cm^-5. Echocardiography showed increase of RV EF from 36±2.3 to 51.8±4.1% and decrease of RV end-diastolic volume from 109.4±39.2 to 39.1±6.8 ml. According CT-angiography there was decrease of pulmonary trunk diameter from 35.10±5.25 to 30.30±8.65 mm.

CONCLUSION

Our 5-year data show that pulmonary thrombendarterectomy has high long-term effectiveness in patients with proximal form of chronic postembolic pulmonary hypertension.

Pulmonary endarterectomy outputs in chronic thromboembolic pulmonary hypertension

BACKGROUND AND OBJECTIVE

Pulmonary thromboendarterectomy surgery is the treatment of choice for patients with chronic thromboembolic pulmonary hypertension; extremely high pulmonary vascular resistance constitutes a risk factor for hospital mortality. The objective of this study was to analyze the immediate and long-term results of the surgical treatment of chronic thromboembolic pulmonary hypertension in patients with very severe pulmonary hypertension.

MATERIAL AND METHODS

Since February 1996, we performed 160 pulmonary thromboendarterectomies. We divided the patient population in 2 groups: group 1, which included 40 patients with pulmonary vascular resistance≥1090dyn/sec/cm^-5, and group 2, which included the remaining 120 patients.

RESULTS

Hospital mortality (15 vs. 2.5%), reperfusion pulmonary edema (33 vs. 14%) and heart failure (23 vs. 3.3%) were all higher in group 1; however, after one year of follow-up, there were no significant differences in the clinical, hemodynamic and echocardiographic conditions of both groups. Survival rate after 5 years was 77% in group 1 and 92% in group 2 (P=.033). After the learning curve including the 46 first patients, there was no difference in hospital mortality (3.8 vs. 2.3%) or survival rate after 5 years (96.2% in group 1 and 96.2% in group 2).

CONCLUSIONS

Pulmonary thromboendarterectomy is linked to significantly higher morbidity and mortality rates in patients with severe chronic thromboembolic pulmonary hypertension. Nevertheless, these patients benefit the same from the procedure in the mid-/long-term. In our experience, after the learning curve, this surgery is safe in severe pulmonary hypertension and no level of pulmonary vascular resistance should be an absolute counter-indication for this surgery.

Guanylate cyclase stimulators for pulmonary hypertension

BACKGROUND

Pulmonary hypertension is a condition of complex aetiology that culminates in right heart failure and early death. Soluble guanylate cyclase (sGC) stimulators are a promising class of agents that have recently gained approval for use.

OBJECTIVES

To evaluate the efficacy of sGC stimulators in pulmonary hypertension.

SEARCH METHODS

We searched CENTRAL (Cochrane Central Register of Controlled Trials), MEDLINE, EMBASE and the reference lists of articles. Searches are current as of 12 February 2016.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) involving participants with pulmonary hypertension of all ages, severities and durations of treatment.

DATA COLLECTION AND ANALYSIS

AW, MS and RW independently selected studies, assessed evidence quality and extracted data. This process was overseen by RT and SG. All included studies were sponsored by the drug manufacturer.

MAIN RESULTS

Five trials involving 962 participants are included in this review. All trials were of relatively short duration (< 16 weeks). Due to the heterogenous aetiology of pulmonary hypertension in participants, results are best considered according to each pulmonary hypertension subtype.Pooled analysis shows a mean difference (MD) increase in six-minute walking distance (6MWD) of 30.13 metres (95% CI 5.29 to 54.96; participants = 659; studies = 3). On subgroup analysis, for pulmonary arterial hypertension (PAH) there was no effect noted (6MWD; MD 11.91 metres, 95% CI -44.92 to 68.75; participants = 398; studies = 2), and in chronic thromboembolic pulmonary hypertension (CTEPH) sGC stimulators improved 6MWD by an MD of 45 metres (95% CI 23.87 to 66.13; participants = 261; studies = 1). Data for left heart disease-associated PH was not available for pooling. Importantly, when participants receiving phosphodiesterase inhibitors were excluded, sGC stimulators increased 6MWD by a MD of 36 metres in PAH. The second primary outcome, mortality, showed no change on pooled analysis against placebo (Peto odds ratio (OR) 0.57, 95% CI 0.18 to 1.80).Pooled secondary outcomes include an increase in World Health Organization (WHO) functional class (OR 1.53, 95% CI 0.87 to 2.72; participants = 858; studies = 4), no effect on clinical worsening (OR 0.45, 95% CI 0.17 to 1.14; participants = 842; studies = 3), and a reduction in mean pulmonary artery pressure (MD -2.77 mmHg, 95% CI -4.96 to -0.58; participants = 744; studies = 5). There was no significant difference in serious adverse events on pooled analysis (OR 1.12, 95% CI 0.66 to 1.90; participants = 818; studies = 5) or when analysed at PAH (MD -3.50, 95% CI -5.54 to -1.46; participants = 344; studies = 1), left heart disease associated subgroups (OR 1.56, 95% CI 0.78 to 3.13; participants = 159; studies = 2) or CTEPH subgroups (OR 1.29, 95% CI 0.65 to 2.56; participants = 261; studies = 1).It is important to consider the results for PAH in the context of a person who is not also receiving a phosphodiesterase-V inhibitor, a contra-indication to sGC stimulator use. It should also be noted that CTEPH results are applicable to inoperable or recurrent CTEPH only.Evidence was rated according to the GRADE scoring system. One outcome was considered high quality, two were moderate, and eight were of low or very low quality, meaning that for many of the outcomes the true effect could differ substantially from our estimate. There were only minor concerns regarding the risk of bias in these trials, all being RCTs largely following the original protocol. Most trials employed an intention-to-treat analysis.

AUTHORS' CONCLUSIONS

sGC stimulators improve pulmonary artery pressures in people with PAH (who are treatment naive or receiving a prostanoid or endothelin antagonist) or those with recurrent or inoperable CTEPH. In these settings this can be achieved without notable complication. However, sGC stimulators should not be taken by people also receiving phosphodiestase-V inhibitors or nitrates due to the risks of hypotension, and there is currently no evidence supporting their use in pulmonary hypertension associated with left heart disease. There is no evidence supporting their use in children. These conclusions are based on data with limitations, including unavailable data from two of the trials.

Severity of pulmonary hypertension and obesity are not associated with worse functional outcomes after pulmonary thromboendarterectomy

Predictors of functional outcomes in patients with chronic thromboembolic pulmonary hypertension (CTEPH) undergoing pulmonary thromboendarterectomy (PTE) are important to identify preoperatively. We hypothesized that baseline severity of pulmonary hypertension and obesity would not be associated with 6-month functional outcomes after PTE. Clinical and hemodynamic data were collected on consecutive patients undergoing PTE from 2008 to 2014. Patients were stratified according to baseline pulmonary vascular resistance (PVR) and body mass index (BMI). Six-minute walk distance (6MWD), New York Heart Association functional class (FC), and echocardiography were assessed in each group at baseline and 6 months after PTE. Regression analyses were performed to evaluate for associations between functional outcomes and baseline PVR and BMI. Forty-two patients underwent PTE and had 6-month follow up data. In comparisons of patients with high and low baseline PVR, the baseline characteristics, distribution of disease, 6MWD, and FC were similar. Postoperative hemodynamics for both groups were similar. At 6 months, both groups achieved improvements in FC, and there were no between-group differences in the change in 6MWD or FC. In comparisons of obese and nonobese patients, perioperative and FC improvement were similar; however, obese patients achieved a greater improvement in 6MWD than nonobese patients (P = 0.04). In conclusion, our data suggest that baseline severity of CTEPH and obesity were not associated with worse functional outcome. Further studies are needed to confirm these results, as these findings could have implications for patient selection for PTE.

Perioperative extracorporeal membrane oxygenation bridging in patients undergoing pulmonary endarterectomy

OBJECTIVES

Chronic thromboembolic pulmonary hypertension is the only curable form of pulmonary arterial hypertension. Pulmonary endarterectomy (PEA) has been established as the treatment of choice in these patients producing very satisfying results. Some patients develop severe cardiorespiratory decompensation before PEA or during weaning from cardiopulmonary bypass. This might be due to acute reperfusion oedema and/or right ventricular failure caused by residual hypertension. Extracorporeal membrane oxygenation (ECMO) support has been established as a bridging therapy in cardiorespiratory failure. At our department, we used peripheral veno-arterial ECMO in patients deteriorating before PEA and in patients where weaning from cardiopulmonary bypass was not possible.

METHODS

We conducted a retrospective analysis of all the patients undergoing PEA who needed pre- and/or postoperative veno-arterial ECMO support. Outcomes including survival, morbidity and haemodynamic improvement were compared between patients surviving and non-surviving after ECMO support. Further, we analysed survival and risk factors of patients requiring ECMO versus patients without ECMO support.

RESULTS

Between January 2001 and March 2013, a total of 161 patients underwent PEA at our institution. Thirty-one patients (19.3%) required support with peripheral veno-arterial ECMO, either both, pre- and postoperatively (n = 2), or only postoperatively (n = 29). Twenty-eight patients received ECMO directly in the theatre and 1 patient received ECMO at the ICU after successful weaning from cardiopulmonary bypass after PEA. Twenty-eight patients (90.3%) were successfully weaned from ECMO and 20 patients left the hospital alive giving a salvage rate of 64.5%. For those not requiring ECMO support, in-house mortality was 3.1% (n = 4). In the 3 patients where weaning from ECMO was not possible, lung transplantation was performed as a rescue therapy. Long-term survival in the patients requiring ECMO who survived was worse than survival in the non-ECMO patient group. The only significant risk factor for the use of ECMO was a pulmonary vascular resistance higher than 1000 dynes cm s(-5).

CONCLUSIONS

Pre- and postoperative ECMO bridging in patients undergoing PEA is a feasible option to stabilize patients in a critical pre- and/or postoperative situation and to improve outcome in these patients who would otherwise probably not survive the procedure.

Developments in pulmonary arterial hypertension-targeted therapy for chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease characterised by the presence of organised chronic thromboembolic material occluding the proximal pulmonary arteries and a vasculopathy in the distal pulmonary arterial tree. Pulmonary endarterectomy (PEA) is a potential cure for many patients with CTEPH. However, PEA is not suitable for patients with a significant distal distribution of chronic thromboembolic material or with significant comorbidities. Also, a proportion of patients are left with residual CTEPH post PEA. Until recently, pulmonary arterial hypertension-targeted therapies have been used off licence to treat patients with inoperable or residual CTEPH. The CHEST1 study investigated the use of riociguat and was the first randomised controlled trial to show efficacy in inoperable or residual CTEPH. In this review, we explore the pathophysiology of CTEPH and review the current trial evidence for pulmonary arterial hypertension-targeted therapies. We also include a discussion of physiological considerations that require further investigation.

Pulmonary thromboendarterectomy in 106 patients with chronic thromboembolic pulmonary hypertension

INTRODUCTION

Pulmonary thromboendarterectomy is the treatment of choice in chronic thromboembolic pulmonary hypertension. We report our experience with this technique.

METHODS

Between February 1996 and June 2014, we performed 106 pulmonary thromboendarterectomies. Patient population, morbidity and mortality and the long-term results of this technique (survival, functional improvement and resolution of pulmonary hypertension) are described.

RESULTS

Subjects' mean age was 53±14 years. A total of 89% were WHO functional class III-IV, presurgery mean pulmonary pressure was 49±13mmHg and mean pulmonary vascular resistance was 831±364 dynes.s.cm(-5). In-hospital mortality was 6.6%. The most important post-operative morbidity was reperfusion pulmonary injury, in 20% of patients; this was an independent risk factor (p=0.015) for hospital mortality. With a 31-month median follow-up (interquartile range: 50), 3- and 5-year survival was 90 and 84%. At 1 year, 91% were WHO functional class I-II; mean pulmonary pressure (27±11mmHg) and pulmonary vascular resistance (275±218 dynes.s.cm(-5)) were significantly lower (p<0.05) than before the intervention. Although residual pulmonary hypertension was detected in 14 patients, their survival at 3 and 5 years was 91 and 73%, respectively.

CONCLUSIONS

Pulmonary thromboendarterectomy offers excellent results in chronic thromboembolic pulmonary hypertension. Long-term survival is good, functional capacity improves, and pulmonary hypertension is resolved in most patients.

Pulmonary Endarterectomy

Chronic thromboembolic pulmonary hypertension (CTEPH) results from recurrent or incomplete resolution of pulmonary embolism. CTEPH is much more common than generally appreciated. Although pulmonary embolism (PE) affects a large number of Americans, chronic pulmonary thromboembolic hypertension remains underdiagnosed. It is imperative that all patients with pulmonary hypertension (PH) be screened for the presence of CTEPH since this form of PH is potentially curable with pulmonary endarterectomy (PEA) surgery. The success of this procedure depends greatly on the collaboration of a multidisciplinary team approach that includes pulmonary medicine, cardiothoracic surgery, and cardiac anesthesiology. This review, based on the experience of more than 3000 pulmonary endarterectomy surgeries, is divided into 2 parts. Part I focuses on the clinical history and pathophysiology, diagnostic workup, and intraoperative echocardiography. Part II focuses on the surgical approach, anesthetic management, postoperative care, and complications.

Pulmonary Endarterectomy

Chronic thromboembolic pulmonary hypertension (CTEPH) results from recurrent or incomplete resolution of pulmonary embolism. CTEPH is much more common than generally appreciated. Although pulmonary embolism (PE) affects a large number of Americans, chronic pulmonary hypertension (PH) remains underdiagnosed. It is imperative that all patients with PH be screened for the presence of CTEPH since this form of PH is potentially curable with pulmonary thromboendarterectomy (PTE) surgery. The success of this procedure depends greatly on the collaboration of a multidisciplinary team approach that includes pulmonary medicine, cardiothoracic surgery, and cardiac anesthesiology. This review, based on the experience of more than 3000 pulmonary endarterectomy surgeries, is divided into 2 parts. Part I focuses on the clinical history and pathophysiology, diagnostic workup, and intraoperative echocardiography. Part II focuses on the surgical approach, anesthetic management, postoperative care, and complications.

Outcome of Medically Versus Surgically Treated Patients With Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is an ominous disease leading to progressive right heart failure. Selected patients can be treated by pulmonary endarterectomy (PEA). We assessed long-term clinical outcome of patients with CTEPH who underwent PEA and patients who remained on medical treatment alone. A total of 112 consecutive patients with CTEPH referred between 1998 and 2008 to one center were followed for a mean of 35 (range 0-128) months after diagnosis. All the patients had advanced pulmonary hypertension at baseline. The operated group had higher World Health Organization functional class compared to the nonoperated group. No other differences in hemodynamic, echocardiographic, or biochemical parameters were observed at baseline. Despite the perioperative mortality rate of 9.1%, patients who underwent PEA had significantly lower long-term mortality compared to nonoperated patients (12.7% vs 34.8%; P = .003), and PEA survivors showed sustained clinical improvement. All efforts should be undertaken to perform PEA in all patients with operable CTEPH.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a disease with high mortality and few treatment options. This article reviews the epidemiology of CTEPH and identifies risk factors for its development. The pathobiology and the progression from thromboembolic events to chronically increased right-sided pressures are discussed. The diagnosis and assessment of CTEPH requires several modalities and the role of these is detailed. The pre-operative evaluation assesses peri-operative risk and determines the likelihood of benefit from PTE. Pulmonary thromboendarterectomy (PTE) remains the treatment of choice in appropriate patients. Nonsurgical therapies for CTEPH may provide benefit in patients who cannot be offered surgery.

Riociguat for the treatment of chronic thromboembolic pulmonary hypertension

BACKGROUND

Riociguat, a member of a new class of compounds (soluble guanylate cyclase stimulators), has been shown in previous clinical studies to be beneficial in the treatment of chronic thromboembolic pulmonary hypertension.

METHODS

In this phase 3, multicenter, randomized, double-blind, placebo-controlled study, we randomly assigned 261 patients with inoperable chronic thromboembolic pulmonary hypertension or persistent or recurrent pulmonary hypertension after pulmonary endarterectomy to receive placebo or riociguat. The primary end point was the change from baseline to the end of week 16 in the distance walked in 6 minutes. Secondary end points included changes from baseline in pulmonary vascular resistance, N-terminal pro-brain natriuretic peptide (NT-proBNP) level, World Health Organization (WHO) functional class, time to clinical worsening, Borg dyspnea score, quality-of-life variables, and safety.

RESULTS

By week 16, the 6-minute walk distance had increased by a mean of 39 m in the riociguat group, as compared with a mean decrease of 6 m in the placebo group (least-squares mean difference, 46 m; 95% confidence interval [CI], 25 to 67; P<0.001). Pulmonary vascular resistance decreased by 226 dyn·sec·cm(-5) in the riociguat group and increased by 23 dyn·sec·cm(-5) in the placebo group (least-squares mean difference, -246 dyn·sec·cm(-5); 95% CI, -303 to -190; P<0.001). Riociguat was also associated with significant improvements in the NT-proBNP level (P<0.001) and WHO functional class (P=0.003). The most common serious adverse events were right ventricular failure (in 3% of patients in each group) and syncope (in 2% of the riociguat group and in 3% of the placebo group).

CONCLUSIONS

Riociguat significantly improved exercise capacity and pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension. (Funded by Bayer HealthCare; CHEST-1 and CHEST-2 ClinicalTrials.gov numbers, NCT00855465 and NCT00910429, respectively.)

Clinical outcomes of thromboendarterectomy for chronic thromboembolic pulmonary hypertension: 12-year experience

BACKGROUND

We present our 12-year experience of pulmonary thromboendarterectomy in patients with chronic thromboembolic pulmonary hypertension.

MATERIALS AND METHODS

Between January 1999 and March 2011, 16 patients underwent pulmonary thromboendarterectomy. Eleven patients (69%) were classified as functional class III or IV based on the New York Heart Association (NYHA) classification. Seven patients had a history of inferior vena cava filter insertion, and 5 patients showed coagulation disorders. Pulmonary thromboendarterectomy was performed during total circulatory arrest with deep hypothermia in 14 patients.

RESULTS

In-hospital mortality and late death occurred in 2 patients (12.5%) and 1 patient (6.3%), respectively. Extracorporeal membrane oxygenation support was required in 4 patients who developed severe hypoxemia after surgery. Thirteen of the 14 survivors have been followed up for 54 months (range, 2 to 141 months). The pulmonary arterial systolic pressure and cardiothoracic ratio on chest radiography was significantly decreased after surgery (76±26 mmHg vs. 41±17 mmHg, p=0.001; 55%±8% vs. 48%±3%, p=0.003). Tricuspid regurgitation was reduced from 2.1±1.1 to 0.7±0.6 (p=0.007), and the NYHA functional class was also improved to I or II in 13 patients (81%). These symptomatic and hemodynamic improvements maintained during the late follow-up period.

CONCLUSION

Pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension shows good clinical outcomes with acceptable early and long term mortality.

Evaluation of patients with chronic thromboembolic pulmonary hypertension for pulmonary endarterectomy

Pulmonary hypertension as a result of chronic thromboembolic disease (CTEPH) is potentially curable with pulmonary endarterectomy surgery. Consequently, correctly diagnosing patients with this type of pulmonary hypertension and evaluating these patients with the goal of establishing their candidacy for surgical intervention is of utmost importance. And as advancements in surgical techniques have allowed successful resection of segmental-level chronic thromboembolic disease, the number of CTEPH patients that are deemed suitable surgical candidates has expanded, making it even more important that the evaluation be conducted with greater precision. This article will review a diagnostic approach to patients with suspected chronic thromboembolic disease with an emphasis on the criteria considered in selecting patients for pulmonary endarterectomy surgery.