The imperative of reducing contrast dose in percutaneous coronary intervention

Safety and Efficacy of Minimum- or Zero-Contrast IVUS-Guided Percutaneous Coronary Interventions in Chronic Kidney Disease Patients: A Systematic Review

Conventional percutaneous coronary interventions (PCIs) frequently cause severe complications in chronic kidney disease (CKD) patients. Low-to-zero contrast intravascular ultrasound (IVUS) guided PCIs are promising alternatives in the CKD setting. We aim to systematically review up-to-date literature that have reported data and outcomes of low-to-zero contrast PCIs performed in CKD patients. We searched Embase, PubMed, and Cochrane databases for full-text articles that reported original data regarding efficacy and/or safety outcomes of IVUS-guided PCIs in patients with CKD. The quality of non-randomized trials included was assessed using the Newcastle-Ottawa scale. Six papers were included in the present systematic review: One non-randomized trial, two case series, and three case reports. Given the literature reported so far, contrast-free and IVUS-guided PCI procedures in patients with CKD appear to be safe (both in cardiac and renal outcomes) with a comparable efficacy to the conventional procedure, even in complex atherosclerotic lesions. No patient included in the mentioned studies showed renal function deterioration and did not need renal replacement therapy after the zero-contrast IVUS-guided percutaneous procedures. From a cardiovascular point of view, this technique proved to be safe in terms of cardiovascular outcomes. The undesirable consequences of conventional PCI in the CKD population might soon be effectively hampered by safer low-to-zero contrast IVUS-guided PCI procedures after a mandatory and rigorous evidence-based validation in long-awaited randomized controlled trials.

The effect of establishing pre-angiography thresholds on contrast utilization

INTRODUCTION

Contrast induced nephropathy is linked to contrast utilization and strategies for minimizing renal injury are incorporated into many laboratories that perform coronary angiography. Contrast limits have been described, below which there is minimal incremental increase in the risk of renal injury. Whether a priori acknowledgement of these limits as part of a contrast "Time-Out" reduces contrast utilization has not been established. In this study, we investigate the effect of verbalizing pre-angiography and ½ time contrast thresholds on contrast utilization and associated clinical outcomes.

METHODS

We retrospectively reviewed 5265 cases of coronary angiography (984 with contrast thresholds defined pre-procedure compared to 4281 without pre-defined contrast thresholds). There were two primary endpoints: (1) proportion of procedures that utilized an amount of contrast ≤ threshold, and (2) median difference between amount of contrast utilized and the contrast threshold. Secondary outcomes incorporated indices of renal function, and included changes in serum creatinine levels, eGFR, and CKD stage.

RESULTS

Compared to pre-"Time-Out" group, the post-"Time-Out" group had a higher proportion of procedures with contrast ≤ stated contrast threshold (88% vs 84%, P < 0.002), and a lower amount of total contrast volume (88 mL [IQR 60-136] versus 78 mL [IQR 53-119]). The post-"Time-Out" group also had a lower incidence of any increase in post-procedure serum creatinine (45% vs 36%; P = 0.04), and a larger median decrease of pre- to post-procedure eGFR (P = 0.04).

CONCLUSION

Acknowledgement of contrast threshold as part of a contrast "Time-Out" is associated with reduced overall contrast utilization, and likely minimizes risks of contrast-induced nephropathy.

A Review of Intravascular Ultrasound-based Multimodal Intravascular Imaging: The Synergistic Approach to Characterizing Vulnerable Plaques

Catheter-based intravascular imaging modalities are being developed to visualize pathologies in coronary arteries, such as high-risk vulnerable atherosclerotic plaques known as thin-cap fibroatheroma, to guide therapeutic strategy at preventing heart attacks. Mounting evidences have shown three distinctive histopathological features-the presence of a thin fibrous cap, a lipid-rich necrotic core, and numerous infiltrating macrophages-are key markers of increased vulnerability in atherosclerotic plaques. To visualize these changes, the majority of catheter-based imaging modalities used intravascular ultrasound (IVUS) as the technical foundation and integrated emerging intravascular imaging techniques to enhance the characterization of vulnerable plaques. However, no current imaging technology is the unequivocal "gold standard" for the diagnosis of vulnerable atherosclerotic plaques. Each intravascular imaging technology possesses its own unique features that yield valuable information although encumbered by inherent limitations not seen in other modalities. In this context, the aim of this review is to discuss current scientific innovations, technical challenges, and prospective strategies in the development of IVUS-based multi-modality intravascular imaging systems aimed at assessing atherosclerotic plaque vulnerability.