Noninvasive pulmonary transit time: A new parameter for general cardiac performance.

Area of Science:

• Cardiology
• Medical Imaging
• Ultrasound Technology

Background:

• Pulmonary transit time (PTT) using contrast-enhanced ultrasound (CEUS) is a novel method for evaluating cardiac function.
• PTT measures the contrast agent's transit time from the right to the left ventricle based on indicator dilution principles.
• This study investigated PTT as a measure of general cardiac performance in patients eligible for cardiac resynchronization therapy (CRT).

Purpose of the Study:

• To assess the hypothesis that PTT is a valid indicator of general cardiac performance.
• To evaluate the correlation of PTT with established measures of cardiac function and patient well-being.
• To determine the utility of CEUS-derived PTT in patients undergoing evaluation for CRT.

Main Methods:

• The study included 94 heart failure patients (NYHA class II-IV, LVEF≤35%, QRS≥120 ms) referred for CRT.
• Contrast-enhanced ultrasound (CEUS) was used to measure PTT, with normalized PTT (nPTT) calculated to adjust for heart rate.
• Correlations were analyzed between nPTT and cardiac parameters, NT-proBNP levels, and quality of life scores, stratified by rhythm and NYHA class.

Main Results:

• Normalized PTT (nPTT) showed significant correlations with left ventricular parameters (r=-.487), right ventricular parameters (r=-.282), NT-proBNP (r=0.475), and quality of life (r=0.364).
• Stronger correlations were observed in patients with a sinus rhythm.
• The study population comprised 94 patients, with a mean age of 70±8.9 years.

Conclusions:

• CEUS-derived PTT and nPTT demonstrate fair correlations with systolic and diastolic function, NT-pro-BNP levels, and quality of life.
• CEUS-derived PTT is a noninvasive, easily obtainable, bedside measure.
• PTT shows potential as a future tool for assessing general cardiac performance.