P. Syamasundar Rao, MD and U. Subramaniam, MD
Introduction
Since the description by Gross and Hubbard in 1938,[1] surgical closure has been the conventional treatment of choice for management of Patent Ductus Arteriosus (PDA) and remained so until wider application of the trans-catheter techniques described in 1960s and 1970s by Porstmann, Rashkind and their associates,[2-5] respectively, became clinically relevant.6 A number of devices have been used for percutaneous occlusion of the PDA, as reviewed extensively elsewhere.[7-11] With all the devices used for trans-catheter closure of PDA, the size and shape of the ductus are germane in the selection of the type and size of the device to be implanted.[6,12-15][ Minimal ductal diameter (MDD), measured on aortic arch angiography, forms the basis for categorizing the ductal size (Table 1)[15] and is utilized in the selection of device size.[6,12-15] However, the selection of the patients for trans-catheter occlusion of PDA is largely based on the results of echo-Doppler studies performed during the evaluation of these patients. The objective of this study is to examine the reliability of echocardiography in estimating the angiographic MDD. While the data were collected, analyzed, and presented nearly a decade ago,[16] we have not formally published these data at that time, but believe the data are still valid and useful today, leading us to complete the paper at this time.
Study Subjects and Methods
Study Subjects
During a four-year period ending June 2006, 83 patients were brought to the cardiac catheterization laboratory with intent to close the PDA. An Amplatzer Duct Occluder was implanted across the PDA in 53 patients and Gianturco coil occlusion was performed in 15 patients. No transcatheter intervention was performed in six patients, two because of very high pulmonary vascular resistance, three because the PDAs were too large to safely trans-catheter occlude and one because the PDA was tiny. The selection of the type and size of device used was based on the principles outlined by the senior author (PSR) in prior publications.[6,12-14] Adequate two-dimensional and color Doppler echocardiographic and angiographic MDD measurement data for comparison were available in 47 of these patients. These 47 patients form the subjects for this investigation.
FIGURE 1 Selected video frame from modified parasternal short axis view (ductal view) demonstrating a Patent Ductus Arteriosus (PDA); 2-D measurement of the minimal ductal diameter (*Dist) is shown. DAo, descending aorta; PA, pulmonary artery; RVOT, right ventricular outflow tract.
FIGURE 2 Selected video frame from precordial short axis views demonstrating 2-D measurement (*3.5 mm) of the minimal ductal diameter of patent ductus arteriosus (PDA).
Methods
Echocardiograms
Two-dimensional (2-D), M-mode and Doppler (pulsed, continuous wave and color flow imaging) examination was performed in parasternal long and short axis, apical four- and two-chamber, subcostal and suprasternal notch views in a conventional manner, as described elsewhere,[17,18] with particular attention to define the size of the PDA. Parasternal short-axis or ductal views were used to measure 2-D and color Doppler MDDs. Examples of 2-D (Figures 1 and 2) and color Doppler (Figures 3 and 4) imaging of the PDAs are illustrated in Figures 1 thru 4. Measurements were recorded as shown in these figures. These echo-Doppler studies were performed two weeks to four months prior to cardiac catheterization and trans-catheter closure of PDA.
Angiocardiograms
After securing hemodynamic data during right- and left-heart catheterization in a conventional manner, selective aortic arch cine-angiograms with contrast injection via marker pigtail catheters were performed in 300 right anterior oblique and straight lateral projections. The MDD, length, and diameter of the ampulla of PDA were obtained by measuring digitally, comparing with the distance between the radiopaque markers on the catheter (Figures 5 and 6). While the MDD, length, and diameter of the ampulla of PDA were used in deciding on the type and size of the device selected for occlusion of PDA, the MDD is used for analysis in this study.
To read the full article, please go to the March 2019 Issue of CCT.