Authors: Jeremy Friedman, MD, Robert Wong, MD, Michael Goulet, MD - Cedars-Sinai Medical Center
A 16-year-old male with a history of Tetralogy of Fallot repair with a transannular patch as an infant presents for transcatheter pulmonary valve replacement (TPVR). He has severe pulmonary valve regurgitation with a right ventricular end diastolic volume index of (RVEDVI) of 180 ml/m2, and worsening exercise tolerance. After deployment of the transcatheter pulmonary valve, regional wall motion abnormalities are immediately noted on transesophageal echocardiogram. Which of the following is the most likely cause?
EXPLANATION
Pulmonary valve regurgitation is expected after a Tetralogy of Fallot (TOF) repair with a transannular patch. Long-standing pulmonary valve regurgitation can cause right ventricular (RV) volume overload and dilation. These changes can lead to RV systolic and diastolic dysfunction, RV remodeling, arrhythmias, and exercise intolerance. Pulmonary valve replacement (surgical or percutaneous) is recommended for relief of symptoms in patients with repaired TOF and moderate or greater pulmonary regurgitation (PR) with cardiovascular symptoms not otherwise explained.
The following are the AHA/ACC criteria for pulmonary valve replacement (PVR) in patients with a TOF repair with PR1:
Moderate or severe PR (typically defined as regurgitant fraction >25%) PLUS any two of the following:
1. Cardiovascular symptoms that are not otherwise explained
2. Mild or moderate RV or LV dysfunction
3. Severe RV dilation: RVEDVI of ≥160 mL/m2, OR right ventricular end systolic volume index (RVESVI) ≥ 80 mL/m2, OR right ventricular end diastolic volume (RVEDV) ≥ 2x left ventricular end diastolic volume (LVEDV)
4. Right ventricular systolic pressure (RVSP) ≥ 2/3 systemic pressure
5. Progressive reduction in objective exercise tolerance
Cardiac MRI is a useful tool to quantify RV size and function, pulmonary valve function, pulmonary artery anatomy, and any left heart abnormalities, while cardiac CT is required to evaluate suitable RVOT anatomy for a transcatheter pulmonary valve.
Coronary artery (CA) compression is a well-known complication of TPVR. Congenital and postoperative abnormalities in CA anatomy are seen not only in TOF patients, but also in other patients with conotruncal abnormalities. Even with normal CA anatomy, rotation or anterior displacement of the aorta, surgical reimplantation of CAs, or a dilated pulmonary artery can place the patient at risk for CA compression depending on the relative location of the RVOT.
Coronary artery compression is a life-threatening complication. Because of this possibility, it is crucial for the interventionalist to perform coronary angiography with a simultaneous balloon test of the RVOT prior to pulmonary valve deployment2. This maneuver allows the interventionalist to see, prior to valve deployment, if the transcatheter valve will compress any of the coronary arteries leading to myocardial ischemia and wall motion abnormalities on echocardiography.
A multi-center study by Morray et al looked at 404 patients (median age 18 years) who underwent cardiac catheterization for potential TPVR. CA compression occurred in 5% of patients during test balloon angiography. Patients with TOF and TGA were at highest risk for CA compression. Following successful test balloon angiography and subsequent TPVR, no patient developed clinically significant CA compression2.
Other complications of TPVR include native pulmonary artery or RVOT conduit rupture and ventricular arrhythmias3,4. Risk factors for rupture include heavy calcifications of the conduit or RVOT homograft valve. A contained rupture may be controlled with a covered stent, but a noncontained rupture may be a surgical emergency. Intraoperative or postoperative ventricular arrhythmias may occur due to the interaction between the device and the native RVOT tissue.
In the scenario described above, the correct answer is C) coronary artery compression. Regional wall motion abnormalities are most likely caused by coronary artery compression from the new transcatheter pulmonary valve. There is no note of a PA rupture on imaging or acute right ventricular failure which would lead to global ventricular dysfunction on transesophageal echocardiogram.
REFERENCES
1. Stout, KK, Daniels CJ, Aboulhosn JA, et al. 2018 AHA/ACC guideline for the management of adults with congenital heart disease: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019; 139:e698-e800.
2. Morray, BH, McElhinney DB, Cheatham JP et al. Risk of coronary artery compression among patients referred for transcatheter pulmonary valve implantation. Circulation: Cardiovascular Interventions. 2013; 6:535-542.
3. Mueller AS, McDonald DM, Singh HS, Ginns JN. Heart failure in adult congenital heart disease: Tetralogy of Fallot. Heart Failure Reviews. 2020; 25:583-598.
4. Boudjemline Y, Malekzadeh-Milani S, Patel M et al. “Predictors and outcomes of right ventricular outflow tract conduit rupture during percutaneous pulmonary valve implantation: A multicentre study.” EuroIntervention. 2016; 11:1053-1062.
