The Forgotten Valve: Isolated Severe Tricuspid Valve Stenosis [Case Study]
This case study was originally published in the Circulation journal.
A 67-year-old white man with a history of coronary artery disease status, post–3-vessel coronary artery bypass grafting (13 years earlier), and ischemic heart disease, presented with fatigue and dyspnea on exertion for six months. He had undergone chronic resynchronization therapy defibrillator placement nine months before. He denied any weight gain, paroxysmal nocturnal dyspnea, orthopnea, or lower extremity edema. On physical examination, jugular venous pressure was elevated at 12 cm H2O with prominent a and v waves and positive hepatojugular reflux. He had a grade II/VI systolic ejection murmur at the right upper sternal border and a I/IV holosystolic murmur at the right lower sternal border. His lungs were clear to auscultation, and he had no lower extremity edema.
ECG demonstrated sinus rhythm at a ventricular rate of 90 beats/min. The pulmonary function test and overnight oximetry were within normal limits. The treadmill exercise test was notable for cardiac limitation with peak VO2 of 14.5 mL·kg–1·min–1 (56 percent predicted) and abnormal pulmonary response with high VE/VCO2 and decrease in oxygen saturation to 85 percent with exercise from 94 percent at rest. Transthoracic echocardiogram was notable for severe tricuspid valve stenosis (TS) (diastolic mean gradient 7 mm Hg at a heart rate of 86 beats/min) with mild regurgitation (Figure 1).
Valve morphology was difficult to ascertain owing to a device lead. There was leftward displacement of an atrial septal aneurysm consistent with elevated right atrial mean pressures. Otherwise, right ventricular size was normal with borderline decreased systolic function and an estimated right ventricular systolic pressure of 31 mm Hg with normal left ventricular size and a calculated ejection fraction of 49 percent. Transesophageal echocardiogram demonstrated an atrial septal aneurysm with a large patent foramen ovale resulting in a significant right-to-left shunt at rest (Figure 2). Unfortunately, the tricuspid and pulmonary valve leaflets were not well visualized.
He was further evaluated with left and right heart catheterization, which was notable for elevated mean right atrial pressures at rest and exercise, 5 mm Hg and 19 mm Hg, respectively. There was diastolic transtricuspid gradient of 5 mm Hg at rest, rising to 14 mm Hg with exercise (Figure 3), consistent with TS. His pulmonary artery pressure and pulmonary capillary wedge pressure were normal at rest and during exercise. Infusion of agitated saline during exercise revealed robust right-to-left shunting across the interatrial septum with concomitant decrease in arterial oxygen saturation from 92 percent at rest to 88 percent with exercise.
Given these findings, the patient was taken to the operating room for redo thoracotomy. On such, the large patent foramen ovale and septal aneurysm were visualized, and a severely stenotic tricuspid valve (reported orifice size about the tip of a small finger), as well, with a nonadherent pacemaker lead across the valve. He underwent tricuspid valve replacement with the use of a 33-mm Hancock bioprosthesis and closure of patent foramen ovale without complication. Gross examination of the valve in the pathology laboratory revealed markedly abnormal valvular tissue, characterized by abnormal leaflet thickening with mild to moderate fibrotic fusion of both the valvular and subvalvular apparati (Figure 4). These features, in combination, were suggestive of a postinflammatory process.
The patient had a rare presentation of dyspnea on exertion related to hypoxemia with activity in the setting of severe TS and persistent right-to-left shunt from coexistent patent foramen ovale. During exercise, there was an isolated right atrial pressure rise leading to a significant right-to-left atrial pressure gradient and, hence, right-to-left shunt. Given the shunt physiology, the patient did not sense a relief of symptoms with oxygen therapy. After the operation, his symptoms resolved substantially.
Tricuspid valve stenosis is an uncommon clinical entity that can be seen in the setting of rheumatic heart disease, carcinoid syndrome, metabolic or enzymatic abnormalities, or infective endocarditis. There are few reported cases of pacemaker-mediated TS caused by various mechanisms, including focal tricuspid valve leaflet fibrosis from laceration or perforation and fusion of looped leads with the tricuspid valve apparatus. The main treatment for symptomatic severe TS is interventional. Tricuspid valve surgery is preferable over balloon commissurotomy because the latter can create or worsen tricuspid regurgitation. The pathological findings were consistent with postinflammatory disease, which in a single-center study was observed in 92 percent of pathological specimens of severe TS. However, the exact etiology of isolated severe TS due to postinflammatory disease remains unclear as in our patient.
Authors: Mohammed Al-Hijji, M.D., Jae Yoon Park, M.D., Abdallah El Sabbagh, M.D., Muhammad Amin, M.D., Ph.D., Joseph Maleszewski, M.D., and Daniel Borgeson, M.D.