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Coronary sinus blood flow determination by the thermodilution technique: influence of catheter position and
Insights
Coronary sinus blood flow measurements using thermodilution are sensitive to catheter position. Blood flow values vary significantly with catheter withdrawal, emphasizing the need for standardized placement in research comparing patient groups.
Area of Science:
- Cardiovascular Physiology
- Medical Instrumentation
Background:
- Accurate measurement of coronary sinus blood flow (CSBF) is crucial for assessing myocardial perfusion.
- The thermodilution technique is commonly used for CSBF measurement, but its accuracy can be affected by procedural factors.
Purpose of the Study:
- To investigate the influence of thermodilution catheter withdrawal on CSBF measurements.
- To assess the impact of normal and forced respiration on CSBF readings.
Main Methods:
- CSBF was measured using a thermodilution catheter in 41 patients.
- Catheter position was systematically varied from the great cardiac vein to the coronary sinus ostium.
- CSBF was also measured during normal and forced respiration in 16 patients.
Main Results:
- CSBF increased significantly with catheter withdrawal towards the coronary sinus ostium, with changes ranging from 23 to 68 ml/min per cm.
- Normal respiration caused minor catheter movement (<0.5 cm), while forced respiration induced greater movement (up to 2 cm).
- Both normal and forced respiration influenced CSBF readings, with greater variability during forced breathing.
Conclusions:
- Catheter position is a critical determinant of CSBF measurements obtained via thermodilution.
- Variations in catheter placement can lead to significant differences in reported CSBF values, potentially confounding comparisons between patient cohorts.
- Respiratory variations also impact CSBF measurements, particularly during forced breathing, necessitating careful consideration in study design.
Abstract:
By measuring the coronary sinus blood flow using the thermodilution technique the influence of "thermodilution catheter" withdrawal from the great cardiac vein to the ostium of the coronary sinus was investigated in 41 patients. In addition, the influence of normal and forced respiration on coronary sinus blood flow was measured in 16 of the patients. Mean great cardiac vein flow was measured to 54 +/- 25 ml X min-1. Catheter withdrawal revealed coronary sinus blood flows of 80 +/- 32, 103 +/- 35, 145 +/- 39 and 213 +/- 61 ml X min-1 when the catheter was moved by steps of 1 cm towards the coronary sinus ostium. The coronary sinus blood flow changed between 116 +/- 34 ml X min-1 and 128 +/- 41 ml X min-1 on expiration or inspiration during normal respiration, respectively, when the catheter was placed in a mid-coronary sinus position. Forced respiration changed the coronary sinus blood flow from 98 +/- 41 ml X min-1 during expiration to 196 +/- 76 ml X min-1 during inspiration. The data show that coronary sinus blood flow changes from 23 to 68 ml X min-1 per cm catheter movement, the nearer the ostium the greater the change. Therefore comparison of coronary sinus blood flow between groups of patients would be a comparison between different catheter positions. Normal respiration moves, as judged by the coronary sinus blood flow, the thermodilution catheter by less than 0.5 cm while forced respiration moves the catheter up to 2 cm within the coronary sinus.