Validation of renal artery dimensions measured by magnetic resonance angiography in patients referred for renal sympathetic denervation.

RATIONALE AND OBJECTIVES: Magnetic resonance angiography (MRA) is a well-established modality for the assessment of renal artery stenosis. Using dedicated quantitative analyses, MRA can become a useful tool for assessing renal artery dimensions in patients referred for renal sympathetic denervation (RDN) and for providing accurate measurements of vascular response after RDN. The purpose of this study was to test the reproducibility of a novel MRA quantitative imaging tool and to validate these measurements against intravascular ultrasound (IVUS). MATERIALS AND METHODS: In nine patients referred for renal denervation, renal artery dimensions were measured. Bland-Altman analysis was used to assess the intraobserver and interobserver reproducibility. RESULTS: Mean lumen diameter was 5.8 ± 0.7 mm, with a very good intraobserver and interobserver variability of 0.7% (reproducibility: bias, 0 mm; standard deviation [SD], 0.1 mm) and 1.2% (bias, 0 mm; SD, 0.1 mm), respectively. Mean total lumen volume was 1035.3 ± 403.6 mm(3) with good intraobserver and interobserver variability of 2.9% (bias, -9.7 mm(3); SD, 34.0 mm(3)) and 2.8% (bias, -11.4 mm(3); SD, 42.4 mm(3)). The correlation (Pearson R) between mean lumen diameter measured with MRA and IVUS was 0.750 (P = .002). CONCLUSIONS: Using a novel MRA quantitative imaging tool, renal artery dimensions can be measured with good reproducibility and accuracy. MRA-derived diameters and volumes correlated well with IVUS measurements.

Multimodality Intra-Arterial Imaging Assessment of the Vascular Trauma Induced by Balloon-Based and Nonballoon-Based Renal Denervation Systems.

BACKGROUND: Renal denervation is a new treatment considered for several possible indications. As new systems are introduced, the incidence of acute renal artery wall injury with relation to the denervation method is unknown. We investigated the acute repercussion of renal denervation on the renal arteries of patients treated with balloon-based and nonballoon-based denervation systems by quantitative angiography, intravascular ultrasound, and optical coherence tomography (OCT). METHODS AND RESULTS: Twenty-five patients (50 renal arteries) underwent bilateral renal denervation with 5 different systems, 3 of which balloon-based (Paradise [n=5], Oneshot [n=6], and Vessix V2 [n=5)]) and 2 nonballoon-based (Symplicity [n=6] and EnligHTN [n=3]). Analysis included quantitative angiography and morphometric intravascular ultrasound measurements pre and post procedure and assessment of vascular trauma (dissection, edema, or thrombus) by OCT after denervation. A significant reduction in lumen size by quantitative angiography and intravascular ultrasound was observed in nonballoon denervation but not in balloon denervation. By postdenervation OCT, dissection was seen in 14 arteries (32.6%). The percentage of frames with dissection was higher in balloon-based denervation catheters. Thrombus and edema were detected in 35 (81.4%) and 32 (74.4%) arteries, respectively. In arteries treated with balloon-based denervation that had dissection by OCT, the balloon/artery ratio was higher (1.24 [1.17-1.32] versus 1.10 [1.04-1.18]; P<0.01). CONCLUSIONS: A varying extent of vascular injury was observed after renal denervation in all systems; however, different patterns were identified in balloon-based and in nonballoon-based denervation systems. In balloon denervation, the presence of dissections by OCT was associated with a higher balloon/artery ratio.

Usefulness of the SYNTAX score to predict "no reflow" in patients treated with primary percutaneous coronary intervention for ST-segment elevation myocardial infarction.

The no-reflow phenomenon has been shown to have a significant effect on clinical outcomes in patients with acute ST-segment elevation myocardial infarction. Angiographic features incorporated in the SYNTAX Score (SXScore) obtained on diagnostic angiography during primary percutaneous coronary intervention (PPCI) may be associated with the occurrence of myocardial no-reflow. The aim of this study was to assess the ability of the SXScore to predict no-reflow during PPCI. The SXScore was applied to 669 consecutive patients presenting with acute ST-segment elevation myocardial infarction from November 2006 to February 2008. Angiographic analysis of the PPCI procedure was used to determine no-reflow. The median SXScore was 16 (range 9.5 to 23). No-reflow occurred in 77 patients (12%). On univariate logistic regression analysis, the SXScore showed a strong association (for each 10-unit increase in SXScore, odds ratio 1.42, 95% confidence interval 1.16 to 1.76, p <0.001). On multivariate logistic regression in a model including clinical variables, SXScore was an independent predictor of no-reflow (odds ratio 1.29, 95% confidence interval 1.02 to 1.63, p <0.001). Classification and regression tree analysis identified SXScore >21 as the best cutoff, with patients having double the risk for no-reflow compared to those with SXScore ≤21 (events 9% vs 18%, p = 0.006). In conclusion, the SXScore obtained in the diagnostic phase of PPCI for acute ST-segment elevation myocardial infarction can identify patients at risk for developing no-reflow.

Value of the SYNTAX score in patients treated by primary percutaneous coronary intervention for acute ST-elevation myocardial infarction: The MI SYNTAXscore study.

AIMS: The aims of this study were to evaluate the SYNTAX score (SXscore) calculated at 2 stages during a primary percutaneous intervention (PPCI), that is, SXscore I (diagnostic) and SXscore II (postwiring), and assess its additional value to standard clinical risk scores in acute myocardial infarction. METHODS AND RESULTS: SXscores I and II were applied to 736 consecutive acute ST-elevation myocardial infarction patients referred for PPCI between November 2006 and February 2008. SXscore changed significantly before (I: 16, interquartile range 9.5-23) and after wiring (II: 11, interquartile range 6-19), P < .001. Kaplan-Meier methods were used to compare the primary end point major adverse coronary events (MACE; composite of repeat MI, target vessel revascularization [TVR], and mortality) and secondary end point mortality at 1.5 years in tertiles of SXscore I and SXscore II. Major adverse coronary event was highest in the higher SXscore I tertile (11% vs 15% vs 23%, log-rank <0.01), driven primarily by increased rate of mortality (9% vs 11% vs 17%, log-rank 0.02). Major adverse coronary event was also highest in SXscore II tertile, by a combination of increased mortality and also TVR (TVR rate 2% vs 3% vs 9%, log-rank <0.01). Predictive Cox regression models for mortality and MACE were significantly and similarly improved by the addition of either SXscore I or SXscore II (hazard ratio 1.63, 95% CI 1.18-2.26, P < .01 for MACE) with respective c indices of 0.61 and 0.63 for MACE and 0.60 and 0.61 for mortality. CONCLUSIONS: SXscore during PPCI is a useful tool that provides additional risk stratification to known risk factors of long-term mortality and MACE in patients with ST-elevation myocardial infarction.