Optimization of Preprocedural Full-cycle Computed Tomography in Patients Referred for Transcatheter Tricuspid Valve Repair: Test Bolus Versus Bolus Tracking

Abstract

Purpose/objectives Advancements in transcatheter mitral and tricuspid valve repair have resulted in growing demands in preprocedural computed tomography (CT) imaging. Due to the introduction of multidetector CT (MDCT), shorter acquisition times as well as high rates of heart failure and arrhythmias in this specific patient population, optimal synchronization between the passage of contrast agent and data acquisition is mandatory. There is no consensus on which acquisition technique should be used in this patient population. We aimed to optimize our preprocedural CT protocol comparing bolus tracking (BT) and test bolus (TB) techniques.
Materials and methods We performed a retrospective analysis on 151 patients referred for full-cycle MDCT evaluation for transcatheter tricuspid valve repair comparing BT with TB (BT n=75 TB n=75). Contrast-to-noise ratios (CNR) were obtained. Demographic data, laboratory, electrocardiographic, and transthoracic echocardiography/transoesophageal echocardiography parameters were collected from electronic health records. Also, the volume of contrast agent and saline chaser and radiation dose length product and milliampere seconds were collected.
Results BT and TB resulted in comparable CNR (BT: 0.47 [0.34 to 0.98]; TB: 0.51 [0.41 to 1.40]; P=0.1). BT was associated with a shorter scan duration (BT: 8.3 min [4.1 to 24.4]; TB: 13.9 min [6.2 to 41.4]; P< 0.001), less radiation in terms of dose length product (BT: 1186+/-585; TB: 1383+/-679, P=0.04), and lower total volume administration (BT: 101 mL [63 to 16]; TB: 114 mL [71 to 154]; P< 0.001). In patients with severely impaired ejection fraction (left ventricular ejection fraction [LVEF] <=35%; n=65 [TB n=31; BT n=34]) using the TB technique yielded significantly better image quality in terms of CNR (TB=0.57 [0.41 to 1.07); BT=0.41 [0.34 to 0.65]; P=0.02).
Conclusion In patients with impaired LVEF (LVEF<=35%), the TB technique yielded significantly superior image quality and may be the preferred approach in this specific patient population. BT showed advantages in terms of shorter duration, less radiation, and lower contrast agent volume.

Keywords: valvular heart disease; full cycle computed tomography; bolus tracking; test bolus; heart failure