Investigations Measurement of Vessel Diameter During Angioplasty: Are We Accurately Performing This Task? Loay Salman,* Roberto I. Vazquez-Padron,* Hector Castro,* Mauricio Monrroy,* Yehia Abdelwahed,* Abid Rizvi,* Donna Merrill,† and Arif Asif† *Interventional Nephrology, University of Miami Miller School of Medicine, Miami, Florida, and †Division of Nephrology and Hypertension, Albany Medical College, Albany, New York
ABSTRACT Vessel diameter is objectively measured by a lead ruler positioned in the fluoroscopic field and software calibration during angioplasty. We conducted a prospective study to evaluate the accuracy of lead ruler determination of vessel diameter. Chronic hemodialysis patients undergoing an angioplasty procedure were included in this study (n = 37). Vessel diameter was determined by calibrating the fluoroscopy machine to a ruler with lead markers placed in the fluoroscopic field. The same calibration was used to measure the fully effaced angioplasty balloon in its intravascular location. We compared the measured balloon diameter with the actual (manufacturer’s) diameter. The approximate depth of the ruler
from the measured vessel was also determined. Angioplasty balloons appeared 13.75–40.83% (mean 25.8% 7.015) smaller than the actual size of the balloon (p < 0.0001) when measured using a calibrated fluoroscopic machine. There was a tendency toward the fact that the bigger the distance between the ruler and the vessel (that contained the angioplasty balloon), the more likely the technique underestimated the size of the angioplasty balloon. Lead ruler method underestimates the diameter of the vessel. Recognizing such a discrepancy is important when determining the size of an angioplasty balloon or endovascular stent.
Vessel diameter during an angioplasty procedure is frequently measured by visual inspection. The subjective evaluation relies heavily upon the operator’s experience. A lead ruler placed in the fluoroscopic field and software calibration to determine vessel diameter is an objective assessment and provides a more accurate determination of the diameter by removing any conjectures of optical assessment. However, a major predicament of this approach is the fact that an x-ray beam appreciates the size of an objective differently at various depths. Traditionally, a ruler with lead markers is placed in the fluoroscopic screen adjacent to the patient’s arm that has the arteriovenous access. The lead marker is used to calibrate the fluoroscopic machine for further measurements. Measured vessel diameter not only provides a guide for selecting the balloon size but also determines the size of other tools such as endovascular stents and intravascular coils. However, an x-ray beam appreciates the size of an object differently at various depths. Scientifically,
the most accurate reference for the machine is a control that is located at the same horizontal level as the vascular structure that is being measured. This study investigates the discrepancy of vessel diameter determination when the calibration tool (lead ruler) is place on the operating table (i.e., not in the same horizontal level as the vessel that is being measured). Methods Thirty-seven chronic hemodialysis patients undergoing an angioplasty procedure were included in this study. Vessel diameter was determined by calibrating the fluoroscopy machine to a ruler (with lead markers) placed in the fluoroscopic field. An angioplasty balloon was chosen for angioplasty based on this assessment. The same calibration was used to measure the fully effaced angioplasty balloon in its intravascular position. We compared the measured balloon diameter with the actual (manufacturer’s) diameter. We selected high pressure and noncompliant angioplasty balloons (Conquest angioplasty dilatation catheter and Atlas angioplasty dilatation catheter, BARD Peripheral Vascular, Inc; Phoenix, AZ). Consecutive cases where the balloon has reached a full effacement
Address correspondence to: Loay Salman, MD, Associate Professor of Medicine, Director, Interventional Nephrology, University of Miami Miller School of Medicine, Miami, FL, e-mail: [email protected] Seminars in Dialysis—Vol 27, No 4 (July–August) 2014 pp. E38–E41 DOI: 10.1111/sdi.12164 © 2013 Wiley Periodicals, Inc. E38
E39
MEASUREMENT OF VESSEL DIAMETER DURING ANGIOPLASTY
inside the vessel were used for this analysis. The approximate depth of the ruler from the vessel (that was being measured) was determined to assess the impact of two objects not being in the same horizontal plane during measurements. This was performed by measuring the distance from the surface of the operating table or the arm rest (where the lead ruler had been placed) to the approximate level of the vessel that was undergoing angioplasty in the upper extremity or the thoracic cage (Fig. 1). Balloon measurement was performed at multiple levels and twice by two different operators to reduce operator-dependent error. The value obtained was labeled “measured diameter”. The manufacturer’s balloon diameter was referred to as the “actual diameter”. Local institutional review board approval was obtained for this study. All study procedures were carried out in accordance with the Declaration of Helsinki regarding research involving human subjects. The summary statistics of the patient’s age as well as all other continuous variables were reported as mean standard deviation (SD). Comparison of continuous variables was performed using paired
t-test. The p-value was considered significant if
ABSTRACT Vessel diameter is objectively measured by a lead ruler positioned in the fluoroscopic field and software calibration during angioplasty. We conducted a prospective study to evaluate the accuracy of lead ruler determination of vessel diameter. Chronic hemodialysis patients undergoing an angioplasty procedure were included in this study (n = 37). Vessel diameter was determined by calibrating the fluoroscopy machine to a ruler with lead markers placed in the fluoroscopic field. The same calibration was used to measure the fully effaced angioplasty balloon in its intravascular location. We compared the measured balloon diameter with the actual (manufacturer’s) diameter. The approximate depth of the ruler
from the measured vessel was also determined. Angioplasty balloons appeared 13.75–40.83% (mean 25.8% 7.015) smaller than the actual size of the balloon (p < 0.0001) when measured using a calibrated fluoroscopic machine. There was a tendency toward the fact that the bigger the distance between the ruler and the vessel (that contained the angioplasty balloon), the more likely the technique underestimated the size of the angioplasty balloon. Lead ruler method underestimates the diameter of the vessel. Recognizing such a discrepancy is important when determining the size of an angioplasty balloon or endovascular stent.
Vessel diameter during an angioplasty procedure is frequently measured by visual inspection. The subjective evaluation relies heavily upon the operator’s experience. A lead ruler placed in the fluoroscopic field and software calibration to determine vessel diameter is an objective assessment and provides a more accurate determination of the diameter by removing any conjectures of optical assessment. However, a major predicament of this approach is the fact that an x-ray beam appreciates the size of an objective differently at various depths. Traditionally, a ruler with lead markers is placed in the fluoroscopic screen adjacent to the patient’s arm that has the arteriovenous access. The lead marker is used to calibrate the fluoroscopic machine for further measurements. Measured vessel diameter not only provides a guide for selecting the balloon size but also determines the size of other tools such as endovascular stents and intravascular coils. However, an x-ray beam appreciates the size of an object differently at various depths. Scientifically,
the most accurate reference for the machine is a control that is located at the same horizontal level as the vascular structure that is being measured. This study investigates the discrepancy of vessel diameter determination when the calibration tool (lead ruler) is place on the operating table (i.e., not in the same horizontal level as the vessel that is being measured). Methods Thirty-seven chronic hemodialysis patients undergoing an angioplasty procedure were included in this study. Vessel diameter was determined by calibrating the fluoroscopy machine to a ruler (with lead markers) placed in the fluoroscopic field. An angioplasty balloon was chosen for angioplasty based on this assessment. The same calibration was used to measure the fully effaced angioplasty balloon in its intravascular position. We compared the measured balloon diameter with the actual (manufacturer’s) diameter. We selected high pressure and noncompliant angioplasty balloons (Conquest angioplasty dilatation catheter and Atlas angioplasty dilatation catheter, BARD Peripheral Vascular, Inc; Phoenix, AZ). Consecutive cases where the balloon has reached a full effacement
Address correspondence to: Loay Salman, MD, Associate Professor of Medicine, Director, Interventional Nephrology, University of Miami Miller School of Medicine, Miami, FL, e-mail: [email protected] Seminars in Dialysis—Vol 27, No 4 (July–August) 2014 pp. E38–E41 DOI: 10.1111/sdi.12164 © 2013 Wiley Periodicals, Inc. E38
E39
MEASUREMENT OF VESSEL DIAMETER DURING ANGIOPLASTY
inside the vessel were used for this analysis. The approximate depth of the ruler from the vessel (that was being measured) was determined to assess the impact of two objects not being in the same horizontal plane during measurements. This was performed by measuring the distance from the surface of the operating table or the arm rest (where the lead ruler had been placed) to the approximate level of the vessel that was undergoing angioplasty in the upper extremity or the thoracic cage (Fig. 1). Balloon measurement was performed at multiple levels and twice by two different operators to reduce operator-dependent error. The value obtained was labeled “measured diameter”. The manufacturer’s balloon diameter was referred to as the “actual diameter”. Local institutional review board approval was obtained for this study. All study procedures were carried out in accordance with the Declaration of Helsinki regarding research involving human subjects. The summary statistics of the patient’s age as well as all other continuous variables were reported as mean standard deviation (SD). Comparison of continuous variables was performed using paired
t-test. The p-value was considered significant if
