Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but life-threatening form of pulmonary hypertension (PH) that results from unresolved pulmonary emboli leading to organized fibrotic obstructions in the pulmonary arteries, ultimately causing progressive elevation of pulmonary vascular resistance and right heart failure if untreated. ^[1] Pulmonary endarterectomy (PEA) remains the treatment of choice and potentially curative surgical intervention for eligible patients with CTEPH. ^[2]  First successfully performed in the 1960s, PEA has evolved into a highly specialized procedure requiring cardiopulmonary bypass and deep hypothermic circulatory arrest to safely remove obstructive thromboembolic material from the pulmonary arterial bed. ^[3,4]

Pulmonary Endarterectomy has significantly improved survival and quality of life in patients with operable CTEPH, with perioperative mortality rates declining to less than 5% in experienced centers. ^[5]  The University of California, San Diego (UCSD) pioneered modern PEA techniques and has reported long-term survival rates exceeding 85% at 3 years and 70% at 10 years post-surgery. ^[6] The primary goal of the procedure is to restore pulmonary vascular patency and reduce right ventricular afterload, thereby improving cardiac output and reversing symptoms of right-sided heart failure. ^[7]

Proper patient selection is important to the success of PEA. Candidates must have surgically accessible thromboembolic lesions, primarily in the main, lobar, or segmental pulmonary arteries. ^[8] Preoperative assessment includes right heart catheterization, ventilation-perfusion scanning, computed tomography pulmonary angiography, and pulmonary angiography to determine the location and extent of disease. ^[9] A multidisciplinary CTEPH team—comprising pulmonologists, cardiologists, radiologists, anesthesiologists, and cardiothoracic surgeons—is essential for optimal perioperative management and outcome. ^[10]

Despite the curative potential of PEA, a subset of patients is deemed inoperable due to distal microvascular disease or comorbid conditions. For these individuals, emerging therapies such as balloon pulmonary angioplasty (BPA) and targeted pulmonary vasodilators (e.g., Riociguat) offer alternative or adjunctive treatment strategies. ^[2,9] Nevertheless, PEA remains the gold standard for patients with proximal obstructive lesions and adequate cardiopulmonary reserve.

Understanding the evolving role, surgical challenges, and postoperative management strategies of PEA is equally important. Advances in surgical techniques, intraoperative monitoring, and postoperative care have significantly contributed to favorable outcomes. However, ongoing challenges such as persistent pulmonary hypertension post-PEA and identification of borderline operable cases highlight the need for continued research and innovation in this field. ^{[1, 5]}

 Figure 1: Specimen of bilateral pulmonary endarterectomy

It was a retrospective study conducted at our department. Data of patients who underwent pulmonary endarterectomy operation from August 2022 to August 2025 were retrieved retrospectively from the department database. A total of 7 patients' data were collected. 6 months follow up data was collected

In this retrospective observational series, seven male patients underwent pulmonary endarterectomy (PEA) to treat chronic thromboembolic pulmonary hypertension (CTEPH). Patient demographics and baseline characteristics revealed varied clinical backgrounds. One patient had a prior failed catheter-directed thrombus aspiration (October 2024), and one had right lower limb deep vein thrombosis (DVT). One patient had varicose veins with hypothyroidism, and another two were receiving antitubercular therapy for active tuberculosis. Six patients had isolated CTEPH, and one had an associated right atrial mass.

Functional status at baseline, assessed by the New York Heart Association (NYHA) classification, showed four patients in Class II, two in Class III, and one in Class IV. Preoperative oxygen saturation (SpO₂) ranged from 80% to 97%, reflecting varying degrees of hypoxemia. Postoperatively, SpO₂ improved in all patients, ranging from 85% to 98%.

Preoperative echocardiographic parameters demonstrated right ventricular dysfunction, with tricuspid annular plane systolic excursion (TAPSE) ranging from 10 mm to 18 mm. Severe tricuspid regurgitation (TR) was present in five patients, moderate and mild in one. Postoperative transesophageal echocardiography (TEE) revealed improvement; two patients had mild TR, five had moderate TR; none had severe TR.

Hemodynamic assessments revealed elevated preoperative central venous pressure (CVP), ranging from 12 to 35 mmHg. Postoperative CVP values ranged from 11 to 21 mmHg. Right ventricular (RV) systolic/diastolic pressures decreased from a preoperative range of 40/19 to 56/22 mmHg to postoperative values between 34/14 and 50/22 mmHg. Right ventricular systolic pressure (RVSP) by echocardiography also showed substantial improvement: preoperative values ranged from 22 to 115 mmHg, while at six months postoperatively (n=6), values ranged from 20 to 52 mmHg. Percentage reductions in RVSP ranged from 9% to 79%, indicating variable but clinically significant reductions in RV afterload.

Three patients received preoperative pulmonary vasodilator therapy, which was continued postoperatively in the same subset. Surgical intervention included standard bilateral PEA (n=6) and PEA with concomitant right atrial mass excision (n=1). Cardiopulmonary bypass (CPB) duration ranged from 140 to 254 minutes. Aortic cross-clamp (ACC) times (n=6) ranged from 65 to 190 minutes. Total circulatory arrest (TCA) durations ranged between 20 and 59 minutes, with most patients undergoing multiple short TCA cycles. Custodial cardioplegia was administered in six patients, and Del Nido cardioplegia was used in one.

ICU stay ranged from 2 to 19 days, and total hospital stay varied between 6 and 25 days. One patient experienced a fatal pulmonary haemorrhage on postoperative day 2, while the remaining six patients had uncomplicated recoveries. At six months, the cohort demonstrated significant improvements in oxygenation and RV hemodynamics, supporting the efficacy of PEA in managing advanced CTEPH.

Table: 1. Comparison of pre-operative & post-operative parameters.

(TAPSE - Tricuspid Annular Plane Systolic Excursion, RVSP- Right ventricular Systolic pressure)

Table: 2. Intraoperative  & post operative data

(CPB - Cardiopulmonary Bypass , ACC- Aortic cross clamp, TCA- Total circulatory arrest, ICU- Intensive care unit)

In our study 7 male patients were operated for pulmonary endartectomy with male : female ratio of 7:0. It is found to be 2.6 :1 in study done by  Shetty V et al. ^[21] In our observational series of seven male patients undergoing pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH), we observed substantial clinical improvement in functional status, oxygenation, and right ventricular (RV) hemodynamics, consistent with previously published reports. Kim et al. (2022) reported that PEA led to significant reductions in mean pulmonary artery pressure (mPAP) and right ventricular systolic pressure (RVSP), aligning with our findings, where RVSP reductions ranged from 9% to 79% postoperatively. ^[11] Similarly, Cannon et al. (2020) documented RV function recovery post-PEA, highlighting TAPSE improvement and reduced tricuspid regurgitation, which parallels our postoperative echocardiographic findings of TR downgrading from severe to mild/moderate in all patients. ^[12] In terms of surgical complexity, Madani et al. (2015) emphasized the importance of deep hypothermic circulatory arrest (DHCA) with short TCA cycles, comparable to our use of multiple short cycles (20–27 minutes). ^[13] Our ACC and CPB durations also align with the ranges reported by Wang et al. (2021), who noted average CPB times of 180–250 minutes and ACC times around 120–180 minutes in bilateral PEA. ^[14]

Regarding outcomes, our 14% in-hospital mortality (1/7) is comparable to international benchmarks. Mayer et al. (2019) found in-hospital mortality to be 5–15% in early series, decreasing with centre experience. ^[15] study done by Ignatov G  reported to have pulmonary hemorrhage 1 in 11 patients with  incidence of 9% which is comparable to our sudy with incidence of 14.28%. ^[22] With  experience , centers have reported the incidence between 0.5-2%. [21]. Taniguchi et al. (2018) also reported improvement in NYHA class postoperatively, with most patients improving by at least one class. This mirrors our cohort, where all surviving patients improved from baseline NYHA II–IV to better functional capacity. ^[16] Our patients had significant improvement in SpO₂ postoperatively (85–98%) compared to preoperative values (80–97%), supporting the observations of Jenkins et al. (2016), who demonstrated oxygenation improvements and enhanced exercise tolerance post-PEA. ^[17]

The use of preoperative vasodilator therapy in three of our patients did not adversely affect postoperative outcomes, as supported by findings by Darocha et al. (2019), who advocated cautious continuation in selected patients without operability delay. ^[18] One of our patients required concomitant resection of a right atrial mass, similar to the complex surgical cases described by Bonderman et al. (2014), which showed acceptable outcomes with additional procedures when required. ^[19] Finally, our long-term follow-up demonstrated stable hemodynamic recovery and symptom relief, consistent with the 6-month and 1-year outcomes reported in the international CTEPH registry by Pepke-Zaba et al. (2011), affirming the long-term benefits of PEA in advanced CTEPH. ^[20]

Pulmonary endarterectomy (PEA) remains the definitive treatment for chronic thromboembolic pulmonary hypertension (CTEPH), offering a potential cure by directly removing obstructive thromboembolic material from the pulmonary arteries. This complex surgical procedure, performed under deep hypothermic circulatory arrest, significantly improves pulmonary hemodynamics, right ventricular function, exercise capacity, and overall survival. With advancements in surgical techniques, surgeon experience, perioperative care, and patient selection, the procedure has shown excellent long-term outcomes, especially at experienced centers. Despite its inherent risks, PEA offers substantial clinical and prognostic benefits and should be considered the treatment of choice in eligible CTEPH patients. Multidisciplinary evaluation remains critical to optimize outcomes and identify candidates who may alternatively benefit from balloon pulmonary angioplasty or targeted medical therapy.

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