Chronic Thromboembolic Pulmonary Hypertension Program

By Gustavo Heresi, MD, and Nicholas Smedira, MD

Pulmonary hypertension due to unresolved pulmonary emboli that narrow elastic pulmonary arteries is known as chronic thromboembolic pulmonary hypertension (CTEPH). This condition is frequently missed as the etiology of dyspnea on exertion or pulmonary hypertension. However, CTEPH is particularly important to diagnose, as it is the only form of pulmonary hypertension that can be potentially cured with a complex surgical procedure called pulmonary thromboendarterectomy (PTE, also known as pulmonary endarterectomy or PEA).

Screening for CTEPH

The incidence of CTEPH after an acute pulmonary embolism has been reported to be as low as 0.57 percent and as high as 8.8 percent. One of the most cited studies reported an incidence of 3.8 percent within two years. This translates as one patient developing CTEPH out of every 25 who survive an acute pulmonary embolism. A known thrombophilic condition is observed in only a minority of patients, usually antiphospholipid syndrome.

Furthermore, 25 to 50 percent of patients with CTEPH do not have a history of previous pulmonary embolism. Thus, we recommend that all patients with persistent dyspnea after an acute pulmonary embolism, as well as those with pulmonary hypertension of unclear etiology, be evaluated for CTEPH.

Figure 1.

Screening Options

The screening test of choice is the ventilation/perfusion (VQ) scan, as it has the highest sensitivity for the diagnosis of CTEPH. A normal VQ scan excludes this diagnosis. An abnormal result, usually one or more mismatched segmental or larger perfusion defects, should prompt further evaluation. While advances in CT pulmonary angiography have increased its ability to detect CTEPH, the VQ scan is preferred, given the simplicity of the VQ’s interpretation, and the difficulty in recognizing chronic thromboembolic lesions on CT.

Conventional digital subtraction pulmonary angiography remains the gold standard for CTEPH confirmation and operative planning (Figure 2). Once a diagnosis of CTEPH is established, an assessment of operability is the next step, as PTE surgery offers the potential for cure.

Figure 2.

Treatment Options

Operability assessment is complex and highly dependent on the experience and expertise of the CTEPH team. Factors that are considered include the thrombotic burden, the degree of hemodynamic compromise and the patient’s comorbidities. Pulmonary hypertension-targeted medical therapy is only indicated for patients considered not to be surgical candidates.

Multispecialty Team

Cleveland Clinic has a multidisciplinary team dedicated to the evaluation and treatment of CTEPH patients. The CTEPH program team includes clinicians specializing in pulmonary medicine, cardiothoracic surgery, nuclear medicine, chest radiology, interventional radiology, cardiovascular medicine, and anesthesiology. Our team is evaluating the role of novel imaging techniques, such as single photon emission computed tomography VQ scintigraphy and dual-energy CT scan, which allow for the assessment of pulmonary perfusion, and emerging therapeutic options such as balloon pulmonary angioplasty.

Figure 3.

Proven Results

Over the past 20 years, a total of 150 PTE surgeries have been performed at Cleveland Clinic. Between 1995 and 2010, operative mortality was 11.6 percent. Between 2011 and 2014, volumes doubled and the operative mortality came down to 4.7 percent, a rate comparable to current published literature. With the 2015 surgical volume at the time of writing, in-hospital mortality is down to 3.9 percent.

Hemodynamics Before and After PTE (N = 64) 2011 – 2014

PAP = pulmonary artery pressure, CI = cardiac index, PVR = pulmonary vascular resistance

For the 64 patients who underwent PTE between 2011 and 2014, hemodynamic data show normalization of pulmonary vascular resistance with resultant reduction in pulmonary artery pressure and cardiac index.

Not only are hemodynamic results remarkable and operative mortality low, but long-term outcomes are excellent, with a five-year survival rate of 87.4 percent, compared with 63.3 percent for patients treated with medical therapies.

Figure 4.

Dr. Heresi, Medical Director of the Pulmonary Thromboendarterectomy Program in the Respiratory Institute, can be reached at 216.636.5327 or heresig@ccf.org. Dr. Smedira, a cardiothoracic surgeon, can be reached at 216.445.7052 or smedirn@ccf.org.