PAH in Congenital Heart Disease: Challenges and Advances

Additionally, the diagnostic evaluation is not as straightforward as for typical PAH owing to the abnormal anatomy of these patients. Right ventricular dysfunction is very common, even when PH is not present. Likewise, physical examination and laboratory features may be different than in patients with other forms of PAH, creating further diagnostic challenges. Right heart catheterization also [presents] challenges, both technically and from a data utility perspective. For example, typically we estimate a patient’s cardiac output using thermodilution methods. In many cases, due to intracardiac shunting, thermodilution estimates are not applicable. In patients with complex physiology, it can be difficult to obtain accurate pulmonary arterial and vein saturations to determine cardiac output and the relative pulmonary:systemic flows.

Finally, even accurate data are not always straightforward with respect to how one should interpret pressures (eg, in patients with a Fontan). In these situations, we use a multidisciplinary approach to determine the best diagnosis and the utility of treatment for most patients. Once a diagnosis is made, the data regarding the treatment of PAH are limited to fairly small patient samples. Frequently, we are forced to extrapolate the available data to physiologic or anatomic situations that are not expressly included in many trials. In other cases, surgical or nonpharmacologic remedies may alleviate or improve PH —for example, balloon angiography in patients with pulmonic stenosis. Part of what I find so fascinating about treating these patients is that each one is truly unique.

Cardiology Advisor:Has the mortality rate decreased in this patient group?

Dr Chaisson: I am not sure [whether] the mortality rate related to PH-congenital heart disease has improved significantly or not. What I do know is that patients with PH-congenital heart disease have more favorable outcomes compared with those with non-PH congenital heart disease. This is true even when patients have systemic PA pressures or persistent cyanosis from shunting. My suspicion is that patients today are doing better than [the patients] 20 years ago, but not specifically because of better PH pharmacologic options, but because of improved surgical techniques, improved catheter-based diagnostic and therapeutic techniques, and improved modalities to treat patient comorbidities that may cause PH, such as continuous positive pressure ventilation in concomitant scoliosis. The problem with severe scoliosis is that it causes restrictive lung disease, which can lead to nocturnal hypoventilation and consequent hypercarbia. Continuous positive pressure ventilation is used to prevent hypercarbic respiratory failure.

Cardiology Advisor:How should cardiologists and pulmonologists work together to better monitor these patients?

Dr Chaisson: We have a large adult congenital heart disease referral center and a very tight working relationship with our pediatric and adult congenital heart disease colleagues. The key to a great working relationship is to identify a pulmonologist who has [an] interest in congenital heart disease to see these patients and to maintain close lines of communication. I have several patients who are referred for PH and, upon evaluation, are noted to have congenital heart disease. I have a point of contact to refer these patients, and communication is easy in this regard.

Because most patients with congenital heart disease have had a cardiologist for most of their lives, it is most often that cardiologists are the front line for screening and detection of PH related to congenital heart disease. Our institution’s approach to improving management of PH-congenital heart disease is to have a single point of referral between cardiology and pulmonary medicine. When this occurs, potential cases can be triaged and vetted between teams to determine whether it is prudent for cardiology or pulmonary or both to see the patient.

Cardiology Advisor: Can you share an example of such a case from your own practice?

Dr Chaisson: One example of a great working relationship was with a patient who had a Fontan and a progressive, chronic wheeze. Our adult congenital heart disease cardiologist suspected this was related to declining Fontan status and referred her to me for evaluation of PH-congenital heart disease. If this was present, several invasive options were being mulled, including surgical revision of her shunts.

However, after seeing her, I identified that the patient had severe seasonal allergies with focal areas of wheezing and obstruction on her pulmonary function testing. We were able to treat the patient for asthma with improvement in her symptoms. Today that patient is doing fairly well, and although she may need a Fontan revision or other surgical procedure at some point, our close working relationship was able to improve her quality of life and avoid an unnecessary surgery for now.

References

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2. Gilboa SM, Devine OJ, Kucik JE, et al. Congenital heart defects in the United States: estimating the magnitude of the affected population in 2010. Circulation. 2016;134(2):101-109.
3. Brida M, Gatzoulis MA. Pulmonary arterial hypertension in adult congenital heart disease [published online May 2, 2018]. Heart. doi:10.1136/heartjnl-2017-312106
4. McLaughlin VV, Presberg KW, Doyle RL, et al. Prognosis of pulmonary arterial hypertension: ACCP evidence-based clinical practice guidelines. CHEST. 2004;126(1 Suppl):78S-92S.
5. Agnoletti G, Gala S, Ferroni F, et al. Endothelin inhibitors lower pulmonary vascular resistance and improve functional capacity in patients with Fontan circulation. J Thorac Cardiovasc Surg. 2017;153(6):1468-1475.
6. Hebert A, Mikkelsen UR, Thilen U, et al. Bosentan improves exercise capacity in adolescents and adults after Fontan operation: the TEMPO (Treatment With Endothelin Receptor Antagonist in Fontan Patients, a Randomized, Placebo-Controlled, Double-Blind Study Measuring Peak Oxygen Consumption) study. Circulation. 2014;130(23):2021-2030.

This article originally appeared on The Cardiology Advisor