Trial Outcomes & Findings for Gadobutrol Enhanced MRA of the Renal Arteries (NCT NCT01344460)

The study was conducted at 55 study centers in 13 countries, between 16 May 2011 (first participant first visit) and 06 July 2012 (last participant last visit).

A total of 338 participants were screened, of which 317 were enrolled and 315 received the study drug. The 23 participants who did not receive the study drug included 9 screen failures and 12 premature discontinuations (10 participants withdrew consent and 2 participants for other reasons) and 2 participants never received the study drug.

Gadobutrol Enhanced MRA of the Renal Arteries

Each vascular segment was visualized using unenhanced MRA and gadobutrol-enhanced MRA, characterized by the on-site investigators, three independent blinded readers (reader 1, 2 and 3) and majority readers (the outcome determined by at least two of the blinded readers). The segments were predefined to standardize the blinded reader evaluations. A segment was assessable if it was visualized along its entire length and if any region of stenosis, was measured reliably. There were 6 segments assessed per participant (3 segments in the right renal artery and 3 segments in the left renal artery) and up to 9 segments in participants with renal transplant.

Clinically significant disease was defined as 50 to 99 percent (%) stenosis of a segment, but not occluded as assessed by the SoR. For each segment, the most severe stenosis/narrowing was identified and considered for the evaluation of clinically significant disease.

Clinically significant disease (stenosis) was defined as 50 to 99 percent (%) stenosis of a segment, but not occluded as assessed by the SoR. For each segment, the most severe stenosis/narrowing was identified and considered for the evaluation of clinically significant disease. Specificity = percentage of participants for which the imaging modalities (unenhanced or gadobutrol-enhanced) in the detection and exclusion of clinically significant stenosis.

Clinically significant disease was defined as \>50% stenosis of a segment, but not occluded as assessed by the SoR. For each segment, the most severe stenosis/narrowing was identified and considered for the evaluation of clinically significant disease. Gadobutrol minimum performance criteria was based on a stenosis of 50% calculated from the native vessel diameter.

Clinically significant disease (stenosis) was defined as \>50% stenosis of a segment, but not occluded as assessed by the SoR. For each segment, the most severe stenosis/narrowing was identified and considered for the evaluation of clinically significant disease. Gadobutrol minimum performance criteria was based on a stenosis of 50% calculated from the native vessel diameter.

The length of the left and right renal arteries were measured from the origin at the aorta to the bifurcation into the upper and lower pole arteries or the most distal point of the renal artery which could be visualized. This distal margin was the point where the diameter was still assessable. If there were more than 2 distal branches then the first large branch that was the dominant supply to a renal pole was used as the distal point.

The length of the left and right renal arteries were measured from the origin at the aorta to the bifurcation into the upper and lower pole arteries or the most distal point of the renal artery which could be visualized. This distal margin was the point where the diameter was still assessable. If there were more than 2 distal branches then the first large branch that was the dominant supply to a renal pole was used as the distal point.

The segment reduction in diameter (DIA) of greater than 10% was considered abnormal and measured. The diameter of each of these abnormal segments was measured using electronic calipers (perpendicular to the long axis of the vessel) at the point of most severe stenosis within each segment. Mean of vessel diameters was calculated by segment separately for CTA and MRA readers. For the ease of expression, the following abbreviations will be used: Diameter (DIA), Blinded Reader (BR).

Location within the right and left proximal segment was based on the point of greatest stenosis and was recorded for stenosis \>=50% as: - Within 5 mm of the aorta (or occlusion proximal to the origin of the segment); - Beyond 5 mm from the aorta.

Artifacts were collected for the MRA images on a segmental basis.

The following types of artifacts were considered: Motion artifact (including pulsatility, breathing, swallowing), venous opacification, saturation artifact (for example \[eg\], in-plane flow, turbulence, dephasing, saturation band), susceptibility artifacts (including devices, eg, stents), ringing artifact (eg, bands), bolus timing error, and other (artifact not specified above or no artifact).

The following types of artifacts were considered: Motion artifact (including pulsatility, breathing, swallowing), venous opacification, saturation artifact (for example \[eg\], in-plane flow, turbulence, dephasing, saturation band), susceptibility artifacts (including devices, eg, stents), ringing artifact (eg, bands), bolus timing error, and other (artifact not specified above or no artifact).

The following types of artifacts were considered: Motion artifact (including pulsatility, breathing, swallowing), venous opacification, saturation artifact (for example \[eg\], in-plane flow, turbulence, dephasing, saturation band), susceptibility artifacts (including devices, eg, stents), ringing artifact (eg, bands), bolus timing error, and other (artifact not specified above or no artifact).

An accessory renal artery was defined as an additional, non-dominant, renal artery typically emanating from the aorta and anastomosing distal to the proximal third, segment of that renal artery. It was recorded only as present or absent on the right and left, regardless of how many accessory renal arteries were present.

Any focal dilatation (aneurysmal dilatation) of a segment was recorded. The diameter at the widest point was measured with the electronic calipers if a dilatation was present in any segment. The number of participants with an aneurysmal dilatation in each segment (proximal, mid- and distal) in the right and the left renal arteries assessed by gadobutrol-enhanced MRA and unenhanced MRA were reported.

Any focal dilatation (aneurysmal dilatation) of a segment was recorded. The diameter at the widest point was measured with the electronic calipers if a dilatation was present in any segment. The number of participants with an aneurysmal dilatation in each segment (proximal, mid- and distal) in the right and the left renal arteries assessed by gadobutrol-enhanced MRA and unenhanced MRA were reported.

Diagnostic confidence was evaluated to determine the level of certainty that the blinded readers assigned to a diagnosis for each segment. This was defined as the degree of confidence that the information on the MRA images represented the true and complete clinical picture of a particular segment. The degree of confidence was rated on a 4-point scale: 1=Not confident; 2=Somewhat confident; 3=Confident; 4=Very confident.

A measure of diagnostic value was the reduction in the number of additional diagnostic imaging studies recommended/ordered. The clinical investigators and the blinded readers were asked if they had recommended an additional imaging study for each participant, and the data were recorded.

An additional imaging study recommended was specified from the following list: Non-contrast MRA, Contrast-enhanced MRA, CTA, Ultrasound, Digital subtraction catheter angiogram (DSCA), and Nuclear medicine study.

An additional imaging study recommended was specified from the following list: Non-contrast MRA, Contrast-enhanced MRA, CTA, Ultrasound, Digital subtraction catheter angiogram (DSCA), and Nuclear medicine study.

An additional imaging study recommended was specified from the following list: Non-contrast MRA, Contrast-enhanced MRA, CTA, Ultrasound, Digital subtraction catheter angiogram (DSCA), and Nuclear medicine study.

An additional imaging study recommended was specified from the following list: Non-contrast MRA, Contrast-enhanced MRA, CTA, Ultrasound, Digital subtraction catheter angiogram (DSCA), and Nuclear medicine study.